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Sample records for cdii coii feiii

  1. Chitosan film loaded with silver nanoparticles-sorbent for solid phase extraction of Al(III), Cd(II), Cu(II), Co(II), Fe(III), Ni(II), Pb(II) and Zn(II).

    Science.gov (United States)

    Djerahov, Lubomir; Vasileva, Penka; Karadjova, Irina; Kurakalva, Rama Mohan; Aradhi, Keshav Krishna

    2016-08-20

    The present study describes the ecofriendly method for the preparation of chitosan film loaded with silver nanoparticles (CS-AgNPs) and application of this film as efficient sorbent for separation and enrichment of Al(III), Cd(II), Cu(II), Co(II), Fe(III), Ni(II), Pb(II) and Zn(II). The stable CS-AgNPs colloid was prepared by dispersing the AgNPs sol in chitosan solution at appropriate ratio and further used to obtain a cast film with very good stability under storage and good mechanical strength for easy handling in aqueous medium. The incorporation of AgNPs in the structure of CS film and interaction between the polymer matrix and nanoparticles were confirmed by UV-vis and FTIR spectroscopy. The homogeneously embedded AgNPs (average diameter 29nm, TEM analysis) were clearly observed throughout the film by SEM. The CS-AgNPs nanocomposite film shows high sorption activity toward trace metals under optimized chemical conditions. The results suggest that the CS-AgNPs nanocomposite film can be feasibly used as a novel sorbent material for solid-phase extraction of metal pollutants from surface waters.

  2. Spectral and thermodynamic properties of Ag(I), Au(III), Cd(II), Co(II), Fe(III), Hg(II), Mn(II), Ni(II), Pb(II), U(IV), and Zn(II) binding by methanobactin from Methylosinus trichosporium OB3b.

    Science.gov (United States)

    Choi, Dong W; Do, Young S; Zea, Corbin J; McEllistrem, Marcus T; Lee, Sung-W; Semrau, Jeremy D; Pohl, Nicola L; Kisting, Clint J; Scardino, Lori L; Hartsel, Scott C; Boyd, Eric S; Geesey, Gill G; Riedel, Theran P; Shafe, Peter H; Kranski, Kim A; Tritsch, John R; Antholine, William E; DiSpirito, Alan A

    2006-12-01

    Methanobactin (mb) is a novel chromopeptide that appears to function as the extracellular component of a copper acquisition system in methanotrophic bacteria. To examine this potential physiological role, and to distinguish it from iron binding siderophores, the spectral (UV-visible absorption, circular dichroism, fluorescence, and X-ray photoelectron) and thermodynamic properties of metal binding by mb were examined. In the absence of Cu(II) or Cu(I), mb will bind Ag(I), Au(III), Co(II), Cd(II), Fe(III), Hg(II), Mn(II), Ni(II), Pb(II), U(VI), or Zn(II), but not Ba(II), Ca(II), La(II), Mg(II), and Sr(II). The results suggest metals such as Ag(I), Au(III), Hg(II), Pb(II) and possibly U(VI) are bound by a mechanism similar to Cu, whereas the coordination of Co(II), Cd(II), Fe(III), Mn(II), Ni(II) and Zn(II) by mb differs from Cu(II). Consistent with its role as a copper-binding compound or chalkophore, the binding constants of all the metals examined were less than those observed with Cu(II) and copper displaced other metals except Ag(I) and Au(III) bound to mb. However, the binding of different metals by mb suggests that methanotrophic activity also may play a role in either the solubilization or immobilization of many metals in situ.

  3. Can Co(II) or Cd(II) substitute for Zn(II) in zinc fingers?

    Indian Academy of Sciences (India)

    P Rabindra Reddy; M Radhika

    2001-02-01

    Zinc finger domains consist of sequences of amino acids containing cysteine and histidine residues tetrahedrally coordinated to a zinc ion. The role of zinc in a DNA binding finger was considered purely structural due to the absence of redox chemistry in zinc. However, whether other metals e.g. Co(II) or Cd(II) can substitute Zn(II) is not settled. For an answer the detailed interaction of Co(II) and Cd(II) with cysteine methylester and histidine methylester has been investigated as a model for the zinc core in zinc fingers. The study was extended to different temperatures to evaluate the thermodynamic parameters associated with these interactions. The results suggest that zinc has a unique role.

  4. Comparative adsorption of Fe(III) and Cd(II) ions on glutaraldehyde crosslinked chitosan–coated cristobalite

    OpenAIRE

    Rahmi; Fathurrahmi; Irwansyah; Arie Purnaratrie

    2015-01-01

    In this study, chitosan was crosslinked with glutaraldehyde and coated on the surface of cristobalite through a dip and phase inversion process. The adsorbent was used in batch experiments to evaluate the adsorption of Fe(III) and Cd(II) ions. A maximum adsorption capacity was observed at a glutaraldehyde concentration in sorbent preparation of 1% (w/w). The equilibrium adsorption quantity was determined to be a function of the solution pH, initial concentration and agitation period. Langmuir...

  5. Comparative adsorption of Fe(III and Cd(II ions on glutaraldehyde crosslinked chitosan–coated cristobalite

    Directory of Open Access Journals (Sweden)

    Rahmi

    2015-12-01

    Full Text Available In this study, chitosan was crosslinked with glutaraldehyde and coated on the surface of cristobalite through a dip and phase inversion process. The adsorbent was used in batch experiments to evaluate the adsorption of Fe(III and Cd(II ions. A maximum adsorption capacity was observed at a glutaraldehyde concentration in sorbent preparation of 1% (w/w. The equilibrium adsorption quantity was determined to be a function of the solution pH, initial concentration and agitation period. Langmuir and Freundlich adsorption models were used to describe adsorption isotherms.

  6. Co(II) and Cd(II) complexes derived from heterocyclic Schiff-Bases: synthesis, structural characterisation, and biological activity.

    Science.gov (United States)

    Ahmed, Riyadh M; Yousif, Enaam I; Al-Jeboori, Mohamad J

    2013-01-01

    New monomeric cobalt and cadmium complexes with Schiff-bases, namely, N'-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]furan-2-carbohydrazide (L¹) and N'-[(E)-(3-hydroxy-4-methoxyphenyl)methylidene]thiophene-2-carbohydrazide (L²) are reported. Schiff-base ligands L¹ and L² were derived from condensation of 3-hydroxy-4-methoxybenzaldehyde (iso-vanillin) with furan-2-carboxylic acid hydrazide and thiophene-2-carboxylic acid hydrazide, respectively. Complexes of the general formula [M(L)₂]Cl₂ (where M = Co(II) or Cd(II), L = L¹ or L²) have been obtained from the reaction of the corresponding metal chloride with the ligands. The ligands and their metal complexes were characterised by spectroscopic methods (FTIR, UV-Vis, ¹H, and ¹³C NMR spectra), elemental analysis, metal content, magnetic measurement, and conductance. These studies revealed the formation of four-coordinate complexes in which the geometry about metal ion is tetrahedral. Biological activity of the ligands and their metal complexes against gram positive bacterial strain Bacillus (G+) and gram negative bacteria Pseudomonas (G-) revealed that the metal complexes become less resistive to the microbial activities as compared to the free ligands.

  7. SYNTHESIS, CHARACTERIZATION AND BI OLOGICAL ACTIVITY OF FE-III AND CO-II COMPLEXES DERIVED FROM 4-CHLORO-2-[(2-FURANYLMETHYL-AMINO]-5 SULFAMOYLBENZOIC ACID

    Directory of Open Access Journals (Sweden)

    Suman Malik

    2015-05-01

    Full Text Available The present investigation is an attempt to synth esize and characterize the ligand 4-chloro-2-[(2- furanylmethyl - amino]-5-sulfamoylbenzoic acid, and its Fe-III and Co-II complexes. The nature of bonding and the geometry of the complexes have be en deduced from elemental analysis, magnetic moment measurements and conductivity measurements. Conduc tometric titrations have suggested meta l-ligand ratio of 1:2 for both Fe(III and Co(II complexes. The ligand behaves as a bidentate with N, O donor atoms. The electronic absorption spectra and magnetic susceptibility measurements of th e complexes indicates octahedral geometry for both the complexes. IR, UV-Visible and SEM studies have been carried out to s uggest the tentative structure for the complexes. The synthesized ligand as well as their metal complexes were scree ned for diuretic activity. The results revealed that the complexes are more potent diuretic than the ligand.

  8. Electrochemical studies of DNA interaction and antimicrobial activities of MnII, FeIII, CoII and NiII Schiff base tetraazamacrocyclic complexes

    Science.gov (United States)

    Kumar, Anuj; Vashistha, Vinod Kumar; Tevatia, Prashant; Singh, Randhir

    2017-04-01

    Tetraazamacrocyclic complexes of MnII, FeIII, CoII and NiII have been synthesized by template method. These tetraazamacrocycles have been analyzed with various techniques like molar conductance, IR, UV-vis, mass spectral and cyclic voltammetric studies. On the basis of all these studies, octahedral geometry has been assigned to these tetraazamacrocyclic complexes. The DNA binding properties of these macrocyclic complexes have been investigated by electronic absorption spectra, fluorescence spectra, cyclic voltammetric and differential pulse voltammetric studies. The cyclic voltammetric data showed that ipc and ipa were effectively decreased in the presence of calf thymus DNA, which is a strong evidence for the interaction of these macrocyclic complexes with the calf thymus DNA (ct-DNA). The heterogeneous electron transfer rate constant found in the order: KCoII > KNiII > KMnII which indicates that CoII macrocyclic complex has formed a strong intercalated intermediate. The Stern-Volmer quenching constant (KSV) and voltammetric binding constant were found in the order KSV(CoII) > KSV(NiII) > KSV(MnII) and K+(CoII) > K+(NiII) > K+(MnII) which shows that CoII macrocyclic complex exhibits the high interaction affinity towards ct-DNA by the intercalation binding. Biological studies of the macrocyclic complexes compared with the standard drug like Gentamycin, have shown antibacterial activities against E. coli, P. aeruginosa, B. cereus, S. aureus and antifungal activity against C. albicans.

  9. Synthesis, characterization, DFT calculations and biological studies of Mn(II), Fe(II), Co(II) and Cd(II) complexes based on a tetradentate ONNO donor Schiff base ligand

    Science.gov (United States)

    Abdel-Rahman, Laila H.; Ismail, Nabawia M.; Ismael, Mohamed; Abu-Dief, Ahmed M.; Ahmed, Ebtehal Abdel-Hameed

    2017-04-01

    This study highlights synthesis and characterization of a tetradentate ONNO Schiff base ligand namely (1, 1‧- (pyridine-2, 3-dimethyliminomethyl) naphthalene-2, 2‧-diol) and hereafter denotes as "HNDAP″ and selected metal complexes including Mn(II), Fe(II), Co(II) and Cd(II) as a central metal. HNDAP was synthesized from 1:2 M ratio condensation of 2, 3-diaminopyridine and 2- hydroxy-1-naphthaldhyde, respectively. The stoichiometric ratios of the prepared complexes were estimated using complementary techniques such as; elemental analyses (-C, H, N), FT-IR, magnetic measurements and molar conductivity. Furthermore, their physicochemical studies were carried out using thermal TGA, DTA and kinetic-thermodynamic studies along with DFT calculations. The results of elemental analyses showed that these complexes are present in a 1:1 metal-to- ligand molar ratio. Moreover, the magnetic susceptibilities values at room temperature revealed that Mn(II), Fe(II) and Co(II) complexes are paramagnetic in nature and have an octahedral (Oh) geometry. In contrast, Cd(II) is diamagnetic and stabilizes in square planar sites. The molar conductivity measurements indicated that all complexes are nonelectrolytes in dimethyl formamide. Spectral data suggested that the ligand is as tetradentate and coordinated with Co(II) ion through two phenolic OH and two azomethine nitrogen. However, for Mn(II), Fe(II) and Cd(II) complexes, the coordination occurred through two phenolic oxygen and two azomethine nitrogen with deprotonation of OH groups. The proposed chemical structures have been validated by quantum mechanics calculations. Antimicrobial activities of both the HNDAP Schiff base ligand and its metal complexes were tested against strains of Gram (-ve) E. coli and Gram (+ve) B. subtilis and S. aureus bacteria and C. albicans, A. flavus and T. rubrum fungi. All the prepared compounds showed good results of inhibition against the selected pathogenic microorganisms. The investigated

  10. Synthesis, characterization and in vitro anticancer activity of 18-membered octaazamacrocyclic complexes of Co(II), Ni(II), Cd(II) and Sn(II)

    Science.gov (United States)

    Kareem, Abdul; Zafar, Hina; Sherwani, Asif; Mohammad, Owais; Khan, Tahir Ali

    2014-10-01

    An effective series of 18 membered octaazamacrocyclic complexes of the type [MLX2], where X = Cl or NO3 have been synthesized by template condensation reaction of oxalyl dihydrazide with dibenzoylmethane and metal salt in 2:2:1 molar ratio. The formation of macrocyclic framework, stereochemistry and their overall geometry have been characterized by various physico-chemical studies viz., elemental analysis, electron spray ionization-mass spectrometry (ESI-MS), I.R, UV-Vis, 1H NMR, 13C NMR spectroscopy, X-ray diffraction (XRD) and TGA/DTA studies. These studies suggest formation of octahedral macrocyclic complexes of Co(II), Ni(II), Cd(II) and Sn(II). The molar conductance values suggest nonelectrolytic nature for all the complexes. Thermogravimatric analysis shows that all the complexes are stable up to 600 °C. All these complexes have been tested against different human cancer cell lines i.e. human hepatocellular carcinoma (Hep3B), human cervical carcinoma (HeLa), human breast adenocarcinoma (MCF7) and normal cells (PBMC). The newly synthesized 18-membered octaazamacrocyclic complexes during in vitro anticancer evaluation, displayed moderate to good cytotoxicity on liver (Hep3B), cervical (HeLa) and breast (MCF7) cancer cell lines, respectively. The most effective anticancer cadmium complex (C34H28N10CdO10) was found to be active with IC50 values, 2.44 ± 1.500, 3.55 ± 1.600 and 4.82 ± 1.400 in micro-molar on liver, cervical and breast cancer cell lines, respectively.

  11. Chelating agent free-solid phase extraction (CAF-SPE) of Co(II), Cu(II) and Cd(II) by new nano hybrid material (ZrO{sub 2}/B{sub 2}O{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Yalcinkaya, Ozcan [Gazi University, Science Faculty, Department of Chemistry, 06500, Ankara (Turkey); Kalfa, Orhan Murat [Dumlupinar University, Science and Art Faculty, Department of Chemistry, 43100, Kuetahya (Turkey); Tuerker, Ali Rehber, E-mail: aturker@gazi.edu.tr [Gazi University, Science Faculty, Department of Chemistry, 06500, Ankara (Turkey)

    2011-11-15

    Highlights: {yields} A novel sorbent for solid phase extraction for the preconcentration of metal ions. {yields} Hybrid nano-scale ZrO{sub 2}/B{sub 2}O{sub 3} as a new SPE material. {yields} There is a no need for using any chelating agents before the preconcentration procedure. - Abstract: New nano hybrid material (ZrO{sub 2}/B{sub 2}O{sub 3}) was synthesized and applied as a sorbent for the separation and/or preconcentration of Co(II), Cu(II) and Cd(II) in water and tea leaves prior to their determination by flame atomic absorption spectrometry. Synthesized nano material was characterized by scanning electron microscope, transmission electron microscope and X-ray diffraction. The optimum conditions for the quantitative recovery of the analytes, including pH, eluent type and volume, flow rate of sample solution were examined. The effect of interfering ions was also investigated. Under the optimum conditions, adsorption isotherms and adsorption capacities have been examined. The recoveries of Co(II), Cu(II) and Cd(II) were 96 {+-} 3%, 95 {+-} 3%, 98 {+-} 4% at 95% confidence level, respectively. The analytical detection limits for Co(II), Cu(II), and Cd(II) were 3.8, 3.3, and 3.1 {mu}g L{sup -1}, respectively. The reusability and adsorption capacities (32.2 mg g{sup -1} for Co, 46.5 mg g{sup -1} for Cu and 109.9 mg g{sup -1} for Cd) of the sorbent were found as satisfactory. The accuracy of the method was confirmed by analyzing certified reference material (GBW-07605 Tea leaves) and spiked real samples. The method was applied for the determination of analytes in tap water and tea leaves.

  12. Synthesis, spectroscopic, antimicrobial and DNA cleavage studies of new Co(II), Ni(II), Cu(II), Cd(II), Zn(II) and Hg(II) complexes with naphthofuran-2-carbohydrazide Schiff base

    Science.gov (United States)

    Halli, Madappa B.; Sumathi, R. B.

    2012-08-01

    A series of Co(II), Ni(II), Cu(II), Cd(II), Zn(II) and Hg(II) complexes have been synthesized with newly synthesized Schiff base derived from naphthofuran-2-carbohydrazide and cinnamaldehyde. The elemental analyses of the complexes are confined to the stoichiometry of the type MLCl2 [M = Co(II) and Cu(II)], ML2Cl2 [M = Ni(II), Cd(II), Zn(II) and Hg(II)] respectively, where L is Schiff base ligand. Structures have been proposed from elemental analyses, IR, electronic, mass, 1H NMR, ESR spectral data, magnetic, and thermal studies. The measured low molar conductance values in DMF indicate that the complexes are non-electrolytes. Spectroscopic studies suggest coordination occurs through azomethine nitrogen and carbonyl oxygen of the ligand with the metal ions. The Schiff base and its complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Salmonella typhi) and antifungal (Aspergillus niger, Aspergillus flavus, Cladosporium and Candida albicans) activities by minimum inhibitory concentration (MIC) method. The DNA cleavage studies by agarose gel electrophoresis method was studied for all the complexes.

  13. Synthesis, spectral characterization and biological evaluation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with thiosemicarbazone ending by pyrazole and pyridyl rings

    Science.gov (United States)

    Yousef, T. A.; Abu El-Reash, G. M.; Al-Jahdali, M.; El-Rakhawy, El-Bastawesy R.

    2014-08-01

    Here we present the synthesis of the new Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes with chelating ligand (Z)-(2-((1,3-diphenyl-1H-pyrazol-4-yl)methylene) hydrazinyl)(pyridin-2-ylamino)methanethiol. All the complexes were characterized by elemental analysis, IR, 1H NMR, UV-vis, magnetic susceptibility measurements and EPR spectral studies. IR spectra of complexes showed that the ligand behaves as NN neutral bidentate, NSN mononegative tridentate and NSNN mononegative tetradentate. The electronic spectra and the magnetic measurements suggested the octahedral geometry for all complexes as well as the EPR confirmed the tetragonal distorted octahedral for Cu(II) complex. Cd(II) complex showed the highest inhibitory antioxidant activity either using ABTS method. The SOD-like activity exhibited those Cd(II) and Zn(II) complexes have strong antioxidative properties. We tested the synthesized compounds for antitumor activity and showed that the ability to kill liver (HePG2) and breast (MCF-7) cancer cells definitely.

  14. Synthesis and spectral studies of Cu(II, Ni(II, Co(II, Mn(II, Zn(II and Cd(II complexes of a new macroacyclic ligand N,N’-bis(2-benzothiazolyl-2,6-pyridinedicarboxamide

    Directory of Open Access Journals (Sweden)

    KALAGOUDA B. GUDASI

    2006-05-01

    Full Text Available A new macroacyclic amide ligand N,N’-bis(2-benzothiazolyl-2,6-pyridinedicarboxamide (BPD, formed by the condensation of 2,6-pyridinedicarbonyldichloride with 2-aminobenzothiazole, and its Cu(II, Ni(II, Co(II, Mn(II, Zn(II and Cd(II complexes were synthesized. Their structures were elucidated on the basis of elemental analyses, conductance measurements, magnetic moments, spectral (IR, NMR, UV-Visible, EPR and FAB and thermal studies. The complexes exhibit an octahedral geometry around the metal center. Conductance data of the complexes suggested them to be 1:1 electrolytes. The pentadentate behavior of the ligand was proposed on the basis of spectral studies. The X-band EPR spectra of the Cu(II and Mn(II complexes in the polycrystalline state at room (300 K and liquid nitrogen temperature (77 K were recorded and their salient features are reported.

  15. Spectroscopic and thermal degradation behavior of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes with thiopental sodium anesthesia drug

    Science.gov (United States)

    Refat, Moamen S.

    2013-04-01

    A new series of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized with thiopental sodium anesthesia drug. The elemental analyses of the complexes are confined to stoichiometry of the formulas [M(TPL)3]ṡnH2O (M = Cr(III) or Fe(III); n = 6 or 5), [M(TPL)2(H2O)2]ṡnH2O (M = Mn(II), Co(II) or Ni(II); n = 0 or 4), and [M(TPL)2] (M = Cu(II) or Zn(II); n = 2 or 0) respectively, where TPL is thiopental chelating agent. Structures have been discussed and suggested upon elemental analyses, infrared, Raman, electronic, electron spin resonance, 1H NMR spectral data and magnetic studies. The X-ray powder diffraction (XRD) was performed of metal complexes. The XRD patterns indicate crystalline nature for the complexes. The measured low molar conductance values in dimethylsulfoxide indicate that the complexes are non-electrolyte nature. Spectroscopic discussion refer that coordination take place through three types: Cdbnd N (pyrimidine moiety) nitrogen and C2sbnd S (2-thiolate group) for Cr(III), Mn(II) and Fe(III), C6dbnd O (amido group) oxygen and C2sbnd S (2-thiolate group) for Co(II) and Ni(II), and Cu(II) and Zn(II) ions coordinated via Cdbnd N (pyrimidine moiety) nitrogen, C2dbnd S (2-thiolate group) and C6dbnd O (amido group) oxygen, respectively. The thermal behavior (TG/DTG/DTA) of the complexes was studied and kinetic parameters were determined by Horowitz-Metzger and Coats-Redfern methods. The thiopental and its complexes have been screened for their antimicrobial (G+ and G-) bacteria (Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa) and fungi (Aspergillus flavus and Candida albicans) activities by minimum inhibitory concentration (MIC) method.

  16. Solid-phase extraction of Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from environmental samples by flame atomic absorption spectrometry (FAAS)

    Energy Technology Data Exchange (ETDEWEB)

    Duran, Celal [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Gundogdu, Ali [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bulut, Volkan Numan [Department of Chemistry, Giresun Faculty of Art and Science, Karadeniz Technical University, 28049 Giresun (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Art and Science, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Department of Chemistry, Faculty of Art and Science, Pamukkale University, 20020 Denizli (Turkey); Sentuerk, Hasan Basri [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Tuefekci, Mehmet [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2007-07-19

    A new method using a column packed with Amberlite XAD-2010 resin as a solid-phase extractant has been developed for the multi-element preconcentration of Mn(II), Co(II), Ni(II), Cu(II), Cd(II), and Pb(II) ions based on their complex formation with the sodium diethyldithiocarbamate (Na-DDTC) prior to flame atomic absorption spectrometric (FAAS) determinations. Metal complexes sorbed on the resin were eluted by 1 mol L{sup -1} HNO{sub 3} in acetone. Effects of the analytical conditions over the preconcentration yields of the metal ions, such as pH, quantity of Na-DDTC, eluent type, sample volume and flow rate, foreign ions etc. have been investigated. The limits of detection (LOD) of the analytes were found in the range 0.08-0.26 {mu}g L{sup -1}. The method was validated by analyzing three certified reference materials. The method has been applied for the determination of trace elements in some environmental samples.

  17. Synthesis, investigation and spectroscopic characterization of piroxicam ternary complexes of Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with glycine and DL-phenylalanine

    Science.gov (United States)

    Mohamed, Gehad G.; El-Gamel, Nadia E. A.

    2004-11-01

    The ternary piroxicam (Pir; 4-hydroxy-2-methyl- N-(2-pyridyl)-2H-1,2-benzothiazine-3-carboxamide 1,1-dioxide) complexes of Fe(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with various amino acids (AA) such as glycine (Gly) or DL-phenylalanine (PhA) were prepared and characterized by elemental analyses, molar conductance, IR, UV-Vis, magnetic moment, diffuse reflectance and X-ray powder diffraction. The UV-Vis spectra of Pir and the effect of metal chelation on the different interligand transitions are discussed in detailed manner. IR and UV-Vis spectra confirm that Pir behaves as a neutral bidentate ligand coordinated to the metal ions via the pyridine- N and carbonyl group of the amide moiety. Gly molecule acted as a uninegatively monodentate ligand and coordinate to the metal ions through its carboxylic group, in addition PhA acted as a uninegatively bidentate ligand and coordinate to the metal ions through its carboxylic and amino groups. All the chelates have octahedral geometrical structures while Cu(II)- and Zn(II)-ternary chelates with PhA have square planar geometrical structures. The molar conductance data reveal that most of these chelates are non electrolytes, while Fe(III)-Pir-Gly, Co(II)-, Ni(II)-, Cu(II)- and Zn(II)-Pir-PhA cheletes were 1:1 electrolytes. X-ray powder diffraction is used as a new tool to estimate the crystallinity of chelates as well as to elucidate their geometrical structures.

  18. Synthesis and magnetic properties of Co1-xZnxFe2O4 (x=0÷1) nanopowders by thermal decomposition of Co(II), Zn(II) and Fe(III) carboxylates

    Science.gov (United States)

    Stefanescu, Mircea; Bozdog, Marius; Muntean, Cornelia; Stefanescu, Oana; Vlase, Titus

    2015-11-01

    Nanoparticles of cobalt-zinc ferrite Co1-xZnxFe2O4 with x varying from 0 to 1.0 were prepared by a new method, the thermal decomposition of carboxylates of Fe(III), Co(II) and Zn(II). The obtained carboxylate precursor was characterized by thermal analysis and FT-IR spectroscopy. The precursor was annealed at 350, 600 and 1000 °C. It was found that the spinel cobalt-zinc ferrite was formed starting at 350 °C, but in mixture with simple oxides γ-Fe2O3, Co3O4 and ZnO. At 1000 °C Co1-xZnxFe2O4 was formed quantitatively as a single, well-crystallized phase. The saturation magnetization of the samples annealed at 1000 °C decreased significantly with increasing Zn2+ content from 83.93 emu/g (x=0) to 4.92 emu/g (x=1.0). At 350 and 600 °C the saturation magnetization had the same trend, even if there were contributions of other magnetic phases. Obtaining of spinel ferrite was evidenced by X-ray diffractometry and FT-IR spectrometry. Powder morphology was determined by scanning electron microscopy. Magnetic properties of the synthesized ferrites were investigated employing a conventional induction method.

  19. Antimicrobial, spectral, magnetic and thermal studies of Cu(II), Ni(II), Co(II), UO(2)(VI) and Fe(III) complexes of the Schiff base derived from oxalylhydrazide.

    Science.gov (United States)

    Melha, Khlood Abou

    2008-04-01

    The Schiff base ligand, oxalyl [( 2 - hydroxybenzylidene) hydrazone] [corrected].H(2)L, and its Cu(II), Ni(II), Co(II), UO(2)(VI) and Fe(III) complexes were prepared and tested as antibacterial agents. The Schiff base acts as a dibasic tetra- or hexadentate ligand with metal cations in molar ratio 1:1 or 2:1 (M:L) to yield either mono- or binuclear complexes, respectively. The ligand and its metal complexes were characterized by elemental analyses, IR, (1)H NMR, Mass, and UV-Visible spectra and the magnetic moments and electrical conductance of the complexes were also determined. For binuclear complexes, the magnetic moments are quite low compared to the calculated value for two metal ions complexes and this shows antiferromagnetic interactions between the two adjacent metal ions. The ligand and its metal complexes were tested against a Gram + ve bacteria (Staphylococcus aureus), a Gram -ve bacteria (Escherichia coli), and a fungi (Candida albicans). The tested compounds exhibited high antibacterial activities.

  20. Dinuclear Metallacycles with Single M-X-M Bridges (X = Cl(-), Br(-); M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II)): Strong Antiferromagnetic Superexchange Interactions.

    Science.gov (United States)

    Reger, Daniel L; Pascui, Andrea E; Foley, Elizabeth A; Smith, Mark D; Jezierska, Julia; Wojciechowska, Agnieszka; Stoian, Sebastian A; Ozarowski, Andrew

    2017-03-06

    A series of monochloride-bridged, dinuclear metallacycles of the general formula [M2(μ-Cl)(μ-L)2](ClO4)3 have been prepared using the third-generation, ditopic bis(pyrazolyl)methane ligands L = m-bis[bis(1-pyrazolyl)methyl]benzene (Lm), M = Cu(II), Zn(II), and L = m-bis[bis(3,5-dimethyl-1-pyrazolyl)methyl]benzene (Lm*), M = Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II). These complexes were synthesized from the direct reactions of M(ClO4)2·6H2O, MCl2, and the ligand, Lm or Lm*, in the appropriate stoichiometric amounts. Three analogous complexes of the formula [M2(μ-Cl)(μ-L)2](BF4)3, L = Lm, M = Cu(II), and L = Lm*, M = Co(II), Cu(II), were prepared from the reaction of [M2(μ-F)(μ-L)2](BF4)3 and (CH3)3SiCl. The bromide-bridged complex [Cu2(μ-Br)(μ-Lm*)2](ClO4)3 was prepared by the first method. Three acyclic complexes, [Co2(μ-Lm)μ-Cl4], [Co2(μ-Lm*)Cl4], and [Co2(μ-Lm*)Br4], were also prepared. The structures of all [M2(μ-X)(μ-L)2](3+) (X = Cl(-), Br(-)) complexes have two ditopic bis(pyrazolyl)methane ligands bridging two metals in a metallacyclic arrangement. The fifth coordination site of the distorted trigonal bipyramidal metal centers is filled by a bridging halide ligand that has an unusual linear or nearly linear M-X-M angle. The NMR spectra of [Zn2(μ-Cl)(μ-Lm*)2](ClO4)3 and especially [Cd2(μ-Cl)(μ-Lm*)2](ClO4)3 demonstrate that the metallacycle structure is maintained in solution. Solid state magnetic susceptibility data for the copper(II) compounds show very strong antiferromagnetic exchange interactions, with -J values of 536 cm(-1) for [Cu2(μ-Cl)(μ-Lm)2](ClO4)3·xCH3CN, 720 cm(-1) for [Cu2(μ-Cl)(μ-Lm*)2](ClO4)3, and 945 cm(-1) for [Cu2(μ-Br)(μ-Lm*)2](ClO4)3·2CH3CN. Smaller but still substantial antiferromagnetic interactions are observed with other first row transition metals, with -J values of 98 cm(-1) for [Ni2(μ-Cl)(μ-Lm*)2](ClO4)3, 55 cm(-1) for [Co2(μ-Cl)(μ-Lm*)2](ClO4)3, and 34 cm(-1) for [Fe2(μ-Cl)(μ-Lm*)2](ClO4

  1. Synthesis, spectral characterization, structural investigation and antimicrobial studies of mononuclear Cu(II), Ni(II), Co(II), Zn(II) and Cd(II) complexes of a new potentially hexadentate N2O4 Schiff base ligand derived from salicylaldehyde

    Science.gov (United States)

    Keypour, Hassan; Shayesteh, Maryam; Rezaeivala, Majid; Chalabian, Firoozeh; Elerman, Yalcin; Buyukgungor, Orhan

    2013-01-01

    A new potentially hexadentate N2O4 Schiff base ligand, H2L derived from condensation reaction of an aromatic diamine and salicylaldehyde, and its metal complexes were characterized by elemental analyses, IR, UV-Vis, EI-MS, 1H and 13C NMR spectra, as well as conductance measurements. It has been originated that the Schiff base ligand with Cu(II), Ni(II), Co(II), Cd(II) and Zn(II) ions form mononuclear complexes on 1:1 (metal:ligand) stoichiometry. The conductivity data confirm the non-electrolytic nature of the complexes. Also the crystal structures of the complexes [ZnL] and [CoL] have also been determined by using X-ray crystallographic technique. The Zn(II) and Co(II) complexes show a tetrahedral configuration. Electronic absorption spectra of the Cu(II) and Ni(II) complexes suggest a square-planar geometry around the central metal ion. The synthesized compounds have antibacterial activity against the three Gram-positive bacteria: Bacillus cereus, Enterococcus faecalis and Listeria monocytogenes and also against the three Gram-negative bacteria: Salmonella paraB, Citrobacter freundii and Enterobacter aerogenes. The results showed that in some cases the antibacterial activity of complexes were more than nalidixic acid and amoxicillin as standards.

  2. On the ortho-positronium quenching reactions promoted by Fe(II), Fe(III), Co(III), Ni(II), Zn(II) and Cd(II) cyanocomplexes

    Science.gov (United States)

    Fantola Lazzarini, Anna L.; Lazzarini, Ennio

    The o-Ps quenching reactions promoted in aqueous solutions by the following six cyanocomplexes: [Fe(CN) 6] 4-; [Co(CN) 6] 3-; [Zn(CN) 4] 2-; [Cd(CN) 6] 2-; [Fe(CN) 6] 3-; [Ni(CN) 4] 2- were investigated. The first four reactions probably consist in o-Ps addition across the CN bond, their rate constants at room temperature, Tr, being ⩽(0.04±0.02) × 10 9 M -1 s -1, i.e. almost at the limit of experimental errors. The rate constant of the fifth reaction, in o-Ps oxydation, at Tr is (20.3±0.4) × 10 9 M -1 s -1. The [Ni(CN) 4] 2-k value at Tr, is (0.27±0.01) × 10 9 M -1 s -1, i.e. 100 times less than the rate constants of o-Ps oxydation, but 10 times larger than those of the o-Ps addition across the CN bond. The [Ni(CN) 4] 2- reaction probably results in formation of the following positronido complex: [Ni(CN) 4Ps] 2-. However, it is worth noting that the existence of such a complex is only indirectly deduced. In fact it arises from comparison of the [Ni(CN) 4] 2- rate constant with those of the Fe(II), Zn(II), Cd(II), and Co(III) cyanocomplexes, which, like the Ni(II) cyanocomplex, do not promote o-Ps oxydation or spin exchange reactions.

  3. Synthesis and magnetic properties of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0÷1) nanopowders by thermal decomposition of Co(II), Zn(II) and Fe(III) carboxylates

    Energy Technology Data Exchange (ETDEWEB)

    Stefanescu, Mircea; Bozdog, Marius [University Politehnica Timisoara, Research Institute for Renewable Energy, 2 Piata Victoriei, 300006 Timisoara (Romania); Muntean, Cornelia, E-mail: cornelia.muntean@upt.ro [University Politehnica Timisoara, Research Institute for Renewable Energy, 2 Piata Victoriei, 300006 Timisoara (Romania); Stefanescu, Oana [University Politehnica Timisoara, Research Institute for Renewable Energy, 2 Piata Victoriei, 300006 Timisoara (Romania); Vlase, Titus [West University of Timisoara, 4 B-dul Vasile Parvan, 300223 Timisoara (Romania)

    2015-11-01

    Nanoparticles of cobalt–zinc ferrite Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} with x varying from 0 to 1.0 were prepared by a new method, the thermal decomposition of carboxylates of Fe(III), Co(II) and Zn(II). The obtained carboxylate precursor was characterized by thermal analysis and FT-IR spectroscopy. The precursor was annealed at 350, 600 and 1000 °C. It was found that the spinel cobalt–zinc ferrite was formed starting at 350 °C, but in mixture with simple oxides γ-Fe{sub 2}O{sub 3}, Co{sub 3}O{sub 4} and ZnO. At 1000 °C Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} was formed quantitatively as a single, well-crystallized phase. The saturation magnetization of the samples annealed at 1000 °C decreased significantly with increasing Zn{sup 2+} content from 83.93 emu/g (x=0) to 4.92 emu/g (x=1.0). At 350 and 600 °C the saturation magnetization had the same trend, even if there were contributions of other magnetic phases. Obtaining of spinel ferrite was evidenced by X-ray diffractometry and FT-IR spectrometry. Powder morphology was determined by scanning electron microscopy. Magnetic properties of the synthesized ferrites were investigated employing a conventional induction method. - Highlights: • We synthesized Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} nanoparticles by decomposition of metal-carboxylates. • Decomposition leads to a homogeneous mixture of high reactive amorphous metal oxides. • This new method involves a faster synthesis procedure and yields virtually 100%. • Magnetic properties of Co{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} depend on Zn content and annealing temperature.

  4. New method for the direct determination of dissolved Fe(III) concentration in acid mine waters

    Science.gov (United States)

    To, T.B.; Nordstrom, D.K.; Cunningham, K.M.; Ball, J.W.; McCleskey, R.B.

    1999-01-01

    A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II) >> Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes in Fe reduction-oxidation distribution. Complexed Fe(II) is cleanly removed using a silica-based, reversed-phase adsorbent, yielding excellent isolation of the Fe(III) complex. Iron(III) concentration is measured colorimetrically or by graphite furnace atomic absorption spectrometry (GFAAS). The method requires inexpensive commercial reagents and simple procedures that can be used in the field. Calcium(II), Ni(II), Pb(II), AI(III), Zn(II), and Cd(II) cause insignificant colorimetric interferences for most acid mine waters. Waters containing >20 mg of Cu/L could cause a colorimetric interference and should be measured by GFAAS. Cobalt(II) and Cr(III) interfere if their molar ratios to Fe(III) exceed 24 and 5, respectively. Iron(II) interferes when its concentration exceeds the capacity of the complexing ligand (14 mg/L). Because of the GFAAS elemental specificity, only Fe(II) is a potential interferent in the GFAAS technique. The method detection limit is 2 ??g/L (40 nM) using GFAAS and 20 ??g/L (0.4 ??M) by colorimetry.A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II)???Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes

  5. Cd(II) Speciation in alginate gels

    NARCIS (Netherlands)

    Davis, T.A.; Kalis, E.J.J.; Pinheiro, J.P.; Town, R.M.; Leeuwen, van H.P.

    2008-01-01

    Polysaccharides, such as those occurring in cell walls and biofilms, play an important role in metal speciation in natural aqueous systems. This work describes the speciation of Cd(II) in alginate gels chosen as a model system for biogels. The gels are formed by bridging calcium ions at junction zon

  6. Sequestration and Distribution Characteristics of Cd(II by Microcystis aeruginosa and Its Role in Colony Formation

    Directory of Open Access Journals (Sweden)

    Xiangdong Bi

    2016-01-01

    Full Text Available To investigate the sequestration and distribution characteristics of Cd(II by Microcystis aeruginosa and its role in Microcystis colony formation, M. aeruginosa was exposed to six different Cd(II concentrations for 10 days. Cd(II exposure caused hormesis in the growth of M. aeruginosa. Low concentrations of Cd(II significantly induced formation of small Microcystis colonies (P93% of Cd(II was sequestrated in the groups with lower added concentrations of Cd(II. More than 80% of the sequestrated Cd(II was bioadsorbed by bEPS. The Pearson correlation coefficients of exterior and interior factors related to colony formation of M. aeruginosa revealed that Cd(II could stimulate the production of IPS and bEPS via increasing Cd(II bioaccumulation and bioadsorption. Increased levels of cross-linking between Cd(II and bEPS stimulated algal cell aggregation, which eventually promoted the formation of Microcystis colonies.

  7. Removal of Co(II) from waste water using dry cow dung powder : a green ambrosia to soil

    Science.gov (United States)

    Bagla, Hemlata; Khilnani, Roshan

    2015-04-01

    Co(II) is one of the hazardous products found in the waste streams. The anthropogenic activities are major sources of Co(II) in our environment. Some of the well-established processes such as chemical precipitation, membrane process, liquid extraction and ion exchange have been applied as a tool for the removal of this metal ion [1]. All the above methods are not considered to be greener due to some of their shortcomings such as incomplete metal ion removal, high requirement of energy and reagents, generation of toxic sludge or other waste materials which in turn require further treatments for their cautious disposal. The present investigation entails the application of dry cow dung powder (DCP) as an indigenous, inexpensive and eco-friendly material for the removal of Co(II) from aqueous medium. DCP, is naturally available bio-organic, complex, polymorphic humified fecal matter of cow and is enriched with minerals, carbohydrates, fats, proteins, bile pigments, aliphatic-aromatic species such as 'Humic acid' (HA), Fulvic acid, Ulmic acid [2,3]. Batch biosorption experiments were conducted employing 60Co(II) as a tracer and effect of various process parameters such as pH (1-8), temperature (283-363K), amount of biosorbent (5-40 g/L), time of equilibration (0-30 min), agitation speed (0-4000 rpm), concentration of initial metal ions (0.5-20 mg/mL) and interfering effect of different organic as well as inorganic salts were studied. The Kinetic studies were carried out employing various models but the best fitting was given by Lagergren Pseudo-second order model [4] with high correlation coefficient R2 value of 0.999 and adsorption capacity of 2.31 mg/g. The thermodynamic parameters for biosorption were also evaluated which indicated spontaneous and exothermic process with high affinity of DCP for Co(II). Many naturally available materials are used for biosorption of hazardous metal pollutants, where most of them are physically or chemically modified. In this research

  8. Synthesis and characterization of a surface-grafted Cd(II) ion-imprinted polymer for selective separation of Cd(II) ion from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Li, Min [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Feng, Changgen, E-mail: cgfeng@cast.org.cn [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Li, Mingyu; Zeng, Qingxuan; Gan, Qiang [State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Yang, Haiyan [Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China)

    2015-03-30

    Highlights: • Cd(II) ion-imprinted polymer (Cd(II)-IIP) is prepared. • Cd(II)-IIP shows high stability, good selectivity and reusability. • Cd(II)-IIP can be used as a sorbent for selective removal of Cd(II) ion. - Abstract: A novel Cd(II) ion-imprinted polymer (Cd(II)-IIP) was prepared with surface imprinting technology by using cadmium chloride as a template and allyl thiourea (ATU) as a functional monomer for on-line solid-phase extraction of trace Cd(II) ion and selective separation Cd(II) ion in water samples. The Cd(II)-IIP exhibited good chemical performance and thermal stability. Kinetics studies showed that the equilibrium adsorption was achieved within 8.0 min and the adsorption process can be described by pseudo-second-order kinetic model. Compared to the Cd(II) non-imprinted polymer (Cd(II)-NIP), the Cd(II)-IIP had a higher adsorption capacity and selectivity for Cd(II) ion. The maximum adsorption capacities of the Cd(II)-IIP and Cd(II)-NIP for Cd(II) were 38.30 and 13.21 mg g{sup −1}, respectively. The relative selectivity coefficients of the adsorbent for Cd(II) in the presence of Cu{sup 2+}, Ni{sup 2+}, Co{sup 2+}, Pb{sup 2+} and Zn{sup 2+} were 2.86, 6.42, 11.50, 9.46 and 3.73, respectively. In addition, the Cd(II) ion adsorbed was easy to remove from sorbent and the Cd(II)-IIP exhibited good stability and reusability. The adsorption capacity had no obvious decrease after being used six times. The accuracy of this method was verified by the standard reference material, it was then applied for cadmium ion determination in different types of water samples.

  9. Adsorption of Cd(II) by two variable-charge soils in the presence of pectin.

    Science.gov (United States)

    Wang, Ru-Hai; Zhu, Xiao-Fang; Qian, Wei; Zhao, Min-Hua; Xu, Ren-Kou; Yu, Yuan-Chun

    2016-07-01

    Batch experiments were conducted to investigate cadmium(II) (Cd(II)) adsorption by two variable-charge soils (an Oxisol and an Ultisol) as influenced by the presence of pectin. When pectin dosage was less than 30 g kg(-1), the increase in Cd(II) adsorption with the increasing dose of pectin was greater than that when the pectin dosage was >30 g kg(-1). Although both Langmuir and Freundlich equations fitted the adsorption isotherms of Cd(II) and electrostatic adsorption data of Cd(II) by the two soils well, the Langmuir equation showed a better fit. The increase in the maximum total adsorption of Cd(II) induced by pectin was almost equal in both the soils, whereas the increase in the maximum electrostatic adsorption of Cd(II) was greater in the Oxisol than in the Ultisol because the former contained greater amounts of free Fe/Al oxides than the latter, which, in turn, led to a greater increase in the negative charge on the Oxisol. Therefore, the presence of pectin induced the increase in Cd(II) adsorption by the variable-charge soils mainly through the electrostatic mechanism. Pectin increased the adsorption of Cd(II) by the variable-charge soils and thus decreased the activity and mobility of Cd(II) in these soils.

  10. Synthesis, physicochemical characterization, DFT calculation and biological activities of Fe(III) and Co(II)-omeprazole complexes. Potential application in the Helicobacter pylori eradication

    Science.gov (United States)

    Russo, Marcos G.; Vega Hissi, Esteban G.; Rizzi, Alberto C.; Brondino, Carlos D.; Salinas Ibañez, Ángel G.; Vega, Alba E.; Silva, Humberto J.; Mercader, Roberto; Narda, Griselda E.

    2014-03-01

    The reaction between the antiulcer agent omeprazole (OMZ) with Fe(III) and Co(II) ions was studied, observing a high ability to form metal complexes. The isolated microcrystalline solid complexes were characterized by elemental analysis, X-ray powder diffraction (XRPD), Scanning Electron Microscopy (SEM), magnetic measurements, thermal study, FTIR, UV-Visible, Mössbauer, electronic paramagnetic resonance (EPR), and DFT calculations. The metal-ligand ratio for both complexes was 1:2 determined by elemental and thermal analysis. FTIR spectroscopy showed that OMZ acts as a neutral bidentate ligand through the pyridinic nitrogen of the benzimidazole ring and the oxygen atom of the sulfoxide group, forming a five-membered ring chelate. Electronic, Mössbauer, and EPR spectra together with magnetic measurements indicate a distorted octahedral geometry around the metal ions, where the coordination sphere is completed by two water molecules. SEM and XRPD were used to characterize the morphology and the crystal nature of the complexes. The most favorable conformation for the Fe(III)-OMZ and Co(II)-OMZ complexes was obtained by DFT calculations by using B3LYP/6-31G(d)&LanL2DZ//B3LYP/3-21G(d)&LanL2DZ basis set. Studies of solubility along with the antibacterial activity against Helicobacter pylori for OMZ and its Co(II) and Fe(III) complexes are also reported. Free OMZ and both metal complexes showed antibacterial activity against H. pylori. Co(II)-OMZ presented a minimal inhibitory concentration ˜32 times lower than that of OMZ and ˜65 lower than Fe(III)-OMZ, revealing its promising potential use for the treatment of gastric pathologies associated with the Gram negative bacteria. The morphological changes observed in the cell membrane of the bacteria after the incubation with the metal-complexes were also analyzed by SEM microscopy. The antimicrobial activity of the complexes was proved by the viability test.

  11. A comparative study for the sorption of Cd(II) by K-feldspar and sepiolite as soil components, and the recovery of Cd(II) using rhamnolipid biosurfactant.

    Science.gov (United States)

    Aşçi, Y; Nurbaş, M; Açikel, Y Sağ

    2008-08-01

    This study investigated the sorption characteristics and recovery of selected heavy metal Cd(II) from K-feldspar and sepiolite, representative soil components, using rhamnolipid biosurfactant. Although the proposed technique was classified as a soil bioremediation process, it can also be applied to treatment of waste waters containing Cd(II) ions with minor modifications. The effect of initial Cd(II) concentration on sorption capacity was characterized by determining the sorption isotherms. Of the four models examined, the Freundlich model showed the best fit for the sorption of Cd(II) on K-feldspar, whereas the Langmuir-model was used successfully to characterize the sorption of Cd(II) on sepiolite. Although a high Cd(II) uptake of 7.49 mmol/kg by K-feldspar was obtained, sepiolite was a superior Cd(II) accumulater, with a maximum Cd(II) uptake of 24.66 mmol Cd(II)/kg. The presence of Cd(II) in the sepiolite or K-feldspar prior to addition of the rhamnolipid generally resulted in less rhamnolipid sorption to sepiolite or K-feldspar. The maximum Cd(II) desorption efficiency by rhamnolipid from K-feldspar was substantially higher than that of sepiolite and determined to be 96% of the sorbed Cd(II), whereas only 10.1% of the sorbed Cd(II) from sepiolite was recovered by rhamnolipid solution.

  12. Experimental and theoretical approaches for Cd(II) biosorption from aqueous solution using Oryza sativa biomass.

    Science.gov (United States)

    Fawzy, Manal; Nasr, Mahmoud; Helmi, Shacker; Nagy, Heba

    2016-11-01

    Biomass of Oryza sativa (OS) was tested for the removal of Cd(II) ions from synthetic and real wastewater samples. Batch experiments were conducted to investigate the effects of operating parameters on Cd(II) biosorption. Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy were used to examine the surface characteristics of the Cd(II)-loaded biomass. The maximum removal efficiency of Cd(II) was 89.4% at optimum pH 6.0, biosorbent dose 10.0 g L(-1), initial Cd(II) 50 mg L(-1), and biosorbent particle size 0.5 mm. The applicability of Langmuir and Freundlich isotherms to the sorbent system implied the existence of both monolayer and heterogeneous surface conditions. Kinetic studies revealed that the adsorption process of Cd(II) followed the pseudo-second-order model (r2: 0.99). On the theoretical side, an adaptive neuro-fuzzy inference system (ANFIS) was applied to select the operating parameter that mostly influences the Cd(II) biosorption process. Results from ANFIS indicated that pH was the most influential parameter affecting Cd(II) removal efficiency, indicating that the biomass of OS was strongly pH sensitive. Finally, the biomass was confirmed to adsorb Cd(II) from real wastewater samples with removal efficiency close to 100%. However, feasibility studies of such systems on a large-scale application remain to be investigated.

  13. Inducing magnetic communication in caged dinuclear Co(II) systems.

    Science.gov (United States)

    Caballero-Jiménez, Judith; Habib, Fatemah; Ramírez-Rosales, Daniel; Grande-Aztatzi, Rafael; Merino, Gabriel; Korobkov, Ilia; Singh, Mukesh Kumar; Rajaraman, Gopalan; Reyes-Ortega, Yasmi; Murugesu, Muralee

    2015-05-14

    The synthesis, structural, electronic and magnetic characterization of five dinuclear Co(II) azacryptand compounds (1-5) bridged through different ions are reported. The magnetic exchange interactions, 2J values, obtained from theoretical computations show that the variation of the intermetallic angles and distances lead to antiferromagnetic behaviours. Magneto-structural correlations show a trend, where the angles Co(II)-bridge-Co(II) closer to 180° favour an increase in the superexchange pathway leading to higher AF interaction values.

  14. Concurrent nitrate and Fe(III) reduction during anaerobic biodegradation of phenols in a sandstone aquifer

    DEFF Research Database (Denmark)

    Broholm, Mette; Crouzet, C.; Arvin, Erik

    2000-01-01

    in the anaerobic microcosms were mixed nitrate and Fe(III) reducing. Nitrate and Fe(III) were apparently the dominant electron accepters at high and low nitrate concentrations, respectively. When biomass growth is taken into account, nitrate and Fe(III) reduction constituted sufficient electron acceptor capacity...

  15. A STUDY ON INTERACTION OF Cd(II) AND DIATOMACEOUS EARTH IN ADSORPTION PROCESS

    OpenAIRE

    Nuryono, Nuryono; Suyanta, Suyanta

    2010-01-01

    In this research, interaction occurring in adsorption process between Cd(II) and active site of diatomaceous earth has been studied. The study was carried out by evaluating Cd(II) adsorption on diatomaceous earth at various pHs, either for the earths without treatment, those after being heated or those treated with sulfuric acid and hydrogen chloride. Adsorption was performed by mixing diatomaceous earth, without and with treatments, and Cd(II) solution for one hour at various pHs (2 - 7), an...

  16. Sequestration and Distribution Characteristics of Cd(II) by Microcystis aeruginosa and Its Role in Colony Formation.

    Science.gov (United States)

    Bi, Xiangdong; Yan, Ran; Li, Fenxiang; Dai, Wei; Jiao, Kewei; Zhou, Qixing; Liu, Qi

    2016-01-01

    To investigate the sequestration and distribution characteristics of Cd(II) by Microcystis aeruginosa and its role in Microcystis colony formation, M. aeruginosa was exposed to six different Cd(II) concentrations for 10 days. Cd(II) exposure caused hormesis in the growth of M. aeruginosa. Low concentrations of Cd(II) significantly induced formation of small Microcystis colonies (P bEPS) contents of M. aeruginosa significantly (P 93% of Cd(II) was sequestrated in the groups with lower added concentrations of Cd(II). More than 80% of the sequestrated Cd(II) was bioadsorbed by bEPS. The Pearson correlation coefficients of exterior and interior factors related to colony formation of M. aeruginosa revealed that Cd(II) could stimulate the production of IPS and bEPS via increasing Cd(II) bioaccumulation and bioadsorption. Increased levels of cross-linking between Cd(II) and bEPS stimulated algal cell aggregation, which eventually promoted the formation of Microcystis colonies.

  17. Loading Ag nanoparticles on Cd(II) boron imidazolate framework for photocatalysis

    Science.gov (United States)

    Liu, Min; Zhang, De-Xiang; Chen, Shumei; Wen, Tian

    2016-05-01

    An amine-functionalized Cd(II) boron imidazolate framework (BIF-77) with three-dimensional open structure has been successfully synthesized, which can load Ag nanoparticles (NPs) for photocatalytic degradation of methylene blue (MB).

  18. Multicomponent isotherm for biosorption of Zn(II, CO(II and Cd(II from ternary mixture onto pretreated dried Aspergillus niger biomass

    Directory of Open Access Journals (Sweden)

    Zahra Hajahmadi

    2015-09-01

    Full Text Available In the present study, multicomponent competitive biosorption of heavy metal from aqueous solution onto pretreated dried Aspergillus niger in batch system was investigated. The adsorption data were fitted to the multicomponent Langmuir, Freundlich, Temkin and Sips equations. We used the genetic algorithm of biosorption in ternary mixture to evaluate the potential effects of each metal in the removal of other metals. In order to take both mechanisms of the cell-surface binding and intra-particle diffusion into account, an alternative model was investigated by combining the pseudo-second-order kinetics model and the intra-particle diffusion model. A model describing the process of biosorption by a single-stage batch design was developed and verified based on the Temkin isotherm model. Fundamentally, the outlook from these observations of the experiments that the pretreated dried biomass is a suitable absorbent for the removal of significant amounts of the heavy metal from the effluents of industrial wastewater is promising.

  19. Simultaneous preconcentration of Co(II), Ni(II), Cu(II), and Cd(II) from environmental samples on Amberlite XAD-2000 column and determination by FAAS

    Energy Technology Data Exchange (ETDEWEB)

    Duran, Celal [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)], E-mail: cduran@ktu.edu.tr; Senturk, Hasan Basri [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Elci, Latif [Department of Chemistry, Faculty of Arts and Sciences, Pamukkale University, 20020 Denizli (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Arts and Sciences, Erciyes University, 38039 Kayseri (Turkey); Tufekci, Mehmet [Department of Chemistry, Faculty of Arts and Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

    2009-02-15

    A new method for the preconcentration of some trace metals (Co, Ni, Cu, and Cd) as complexed with ammonium pyrrolidynedithiocarbamate (APDC) was developed using a mini-column filled with Amberlite XAD-2000 resin. Metal contents were determined by flame atomic absorption spectrometry (FAAS) after the metal complexes accumulated on the resin were eluted with 1 M HNO{sub 3} in acetone. The effects of the analytical parameters such as sample pH, quantity of complexing agent, eluent type, resin quantity, sample volume, sample flow rate, and matrix ions were investigated on the recovery of the metals from aqueous solutions. The relative standard deviation (R.S.D.) of the method was <6%. The validation of the method was confirmed using two certified reference materials (CRM TMDW-500 Drinking Water and CRM SA-C Sandy Soil C). The method was successfully applied to some stream waters and mushroom samples from Eastern Black Sea Region (Trabzon city) of Turkey.

  20. Removal of Pb(II), Cd(II) and Co(II) from aqueous solution using Garcinia mangostana L. fruit shell.

    Science.gov (United States)

    Zein, R; Suhaili, R; Earnestly, F; Indrawati; Munaf, E

    2010-09-15

    This study examines the possibility of using mangosteen shell to remove low concentrations of lead, zinc and cobalt (less than 100 mg/l) from aqueous solution. It was found that the biosorption capacities were significantly affected by solution pH, contact time and initial metal ions concentration. Un-extracted and extracted dyes of mangosteen shell were investigated. Moreover higher pH up to 5 favoring higher metal ion removal. Kinetic and isotherm experiments were carried out at the optimal pH: at pH 5.0 for lead and zinc, and at pH 4.0 for cobalt. The metal removal rates were rapid, with 90% of the total adsorption taking place within 60 min. Mangosteen shell showed the highest potential for the removal of toxic metals in aqueous solution.

  1. Simultaneous preconcentration of Co(II), Ni(II), Cu(II), and Cd(II) from environmental samples on Amberlite XAD-2000 column and determination by FAAS.

    Science.gov (United States)

    Duran, Celal; Senturk, Hasan Basri; Elci, Latif; Soylak, Mustafa; Tufekci, Mehmet

    2009-02-15

    A new method for the preconcentration of some trace metals (Co, Ni, Cu, and Cd) as complexed with ammonium pyrrolidynedithiocarbamate (APDC) was developed using a mini-column filled with Amberlite XAD-2000 resin. Metal contents were determined by flame atomic absorption spectrometry (FAAS) after the metal complexes accumulated on the resin were eluted with 1M HNO(3) in acetone. The effects of the analytical parameters such as sample pH, quantity of complexing agent, eluent type, resin quantity, sample volume, sample flow rate, and matrix ions were investigated on the recovery of the metals from aqueous solutions. The relative standard deviation (R.S.D.) of the method was <6%. The validation of the method was confirmed using two certified reference materials (CRM TMDW-500 Drinking Water and CRM SA-C Sandy Soil C). The method was successfully applied to some stream waters and mushroom samples from Eastern Black Sea Region (Trabzon city) of Turkey.

  2. Adsorption of Cd(II) and Pb(II) from aqueous solutions on activated alumina.

    Science.gov (United States)

    Naiya, Tarun Kumar; Bhattacharya, Ashim Kumar; Das, Sudip Kumar

    2009-05-01

    The ability of activated alumina as synthetic adsorbent was investigated for adsorptive removal of Cd(II) and Pb(II) ions from aqueous solutions. Various physico-chemical parameters such as pH, initial metal ion concentration, and adsorbent dosage level and equilibrium contact time were studied. The optimum solution pH for adsorption of Cd(II) and Pb(II) from aqueous solutions was found to be 5. Kinetics data were best described by pseudo-second order model. The effective particle diffusion coefficient of Cd(II) and Pb(II) are of the order of 10(-10) m(2)/s. Values of mass transfer coefficient were estimated as 4.868x10(-6) cm/s and 6.85x10(-6) cm/s for Cd(II) and Pb(II) adsorption respectively. The equilibrium adsorption data for Cd(II) and Pb(II) were better fitted to Langmuir adsorption isotherm model. The thermodynamic studies indicated that the adsorption was spontaneous and exothermic for Cd(II) adsorption and endothermic for Pb(II). The sorption energy calculated from Dubinin-Radushkevich isotherm were 11.85 kJ/mol and 11.8 kJ/mol for the adsorption of Cd(II) and Pb(II) respectively which indicated that both the adsorption processes were chemical in nature. Desorption studies were carried out using dilute mineral acids. Application studies carried out using industrial waste water samples containing Cd(II) and Pb(II) showed the suitability of activated alumina in waste water treatment plant operation.

  3. Biosorption of Cd(II) and Zn(II) by nostoc commune: isotherm and kinetics studies

    Energy Technology Data Exchange (ETDEWEB)

    Morsy, Fatthy M. [Faculty of Science, Botany Department, Assiut University, Assiut (Egypt); Hassan, Sedky H.A. [Department of Biological Environment, Kangwon National University, Kangwon-do (Korea, Republic of); Koutb, Mostafa [Faculty of Science, Botany Department, Assiut University, Assiut (Egypt); Umm Al-Qura University, Faculty of Applied Science, Biology Department, Mecca (Saudi Arabia)

    2011-07-15

    In this study, Nostoc commune (cyanobacterium) was used as an inexpensive and efficient biosorbent for Cd(II) and Zn(II) removal from aqueous solutions. The effect of various physicochemical factors on Cd(II) and Zn(II) biosorption such as pH 2.0-7.0, initial metal concentration 0.0-300 mg/L and contact time 0-120 min were studied. Optimum pH for removal of Cd(II) and Zn(II) was 6.0, while the contact time was 30 min at room temperature. The nature of biosorbent and metal ion interaction was evaluated by infrared (IR) technique. IR analysis of bacterial biomass revealed the presence of amino, carboxyl, hydroxyl, and carbonyl groups, which are responsible for biosorption of Cd(II) and Zn (II). The maximum biosorption capacities for Cd(II) and Zn(II) biosorption by N. commune calculated from Langmuir biosorption isotherm were 126.32 and 115.41 mg/g, respectively. The biosorption isotherm for two biosorbents fitted well with Freundlich isotherm than Langmuir model with correlation coefficient (r{sup 2} < 0.99). The biosorption kinetic data were fitted well with the pseudo-second-order kinetic model. Thus, this study indicated that the N. commune is an efficient biosorbent for the removal of Cd(II) and Zn(II) from aqueous solutions. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Outer cell surface components essential for Fe(III) oxide reduction by Geobacter metallireducens.

    Science.gov (United States)

    Smith, Jessica A; Lovley, Derek R; Tremblay, Pier-Luc

    2013-02-01

    Geobacter species are important Fe(III) reducers in a diversity of soils and sediments. Mechanisms for Fe(III) oxide reduction have been studied in detail in Geobacter sulfurreducens, but a number of the most thoroughly studied outer surface components of G. sulfurreducens, particularly c-type cytochromes, are not well conserved among Geobacter species. In order to identify cellular components potentially important for Fe(III) oxide reduction in Geobacter metallireducens, gene transcript abundance was compared in cells grown on Fe(III) oxide or soluble Fe(III) citrate with whole-genome microarrays. Outer-surface cytochromes were also identified. Deletion of genes for c-type cytochromes that had higher transcript abundance during growth on Fe(III) oxides and/or were detected in the outer-surface protein fraction identified six c-type cytochrome genes, that when deleted removed the capacity for Fe(III) oxide reduction. Several of the c-type cytochromes which were essential for Fe(III) oxide reduction in G. metallireducens have homologs in G. sulfurreducens that are not important for Fe(III) oxide reduction. Other genes essential for Fe(III) oxide reduction included a gene predicted to encode an NHL (Ncl-1-HT2A-Lin-41) repeat-containing protein and a gene potentially involved in pili glycosylation. Genes associated with flagellum-based motility, chemotaxis, and pili had higher transcript abundance during growth on Fe(III) oxide, consistent with the previously proposed importance of these components in Fe(III) oxide reduction. These results demonstrate that there are similarities in extracellular electron transfer between G. metallireducens and G. sulfurreducens but the outer-surface c-type cytochromes involved in Fe(III) oxide reduction are different.

  5. Synthesis, Characterization and Biological Activities of Cu(II, Co(II, Mn(II, Fe(II, and UO2(VI Complexes with a New Schiff Base Hydrazone: O-Hydroxyacetophenone-7-chloro-4-quinoline Hydrazone

    Directory of Open Access Journals (Sweden)

    Nora H. Al-Shaalan

    2011-10-01

    Full Text Available The Schiff base hydrazone ligand HL was prepared by the condensation reaction of 7-chloro-4-quinoline with o-hydroxyacetophenone. The ligand behaves either as monobasic bidentate or dibasic tridentate and contain ONN coordination sites. This was accounted for be the presence in the ligand of a phenolic azomethine and imine groups. It reacts with Cu(II, Ni(II, Co(II, Mn(II, UO2 (VI and Fe(II to form either mono- or binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, NMR, Mass, and UV-Visible spectra. The magnetic moments and electrical conductance of the complexes were also determined. The Co(II, Ni(II and UO2 (VI complexes are mononuclear and coordinated to NO sites of two ligand molecules. The Cu(II complex has a square-planar geometry distorted towards tetrahedral, the Ni(II complex is octahedral while the UO2 (VI complex has its favoured heptacoordination. The Co(II, Mn(II complexes and also other Ni(II and Fe(III complexes, which were obtained in the presence of Li(OH as deprotonating agent, are binuclear and coordinated via the NNNO sites of two ligand molecules. All the binuclear complexes have octahedral geometries and their magnetic moments are quite low compared to the calculated value for two metal ions complexes and thus antiferromagnetic interactions between the two adjacent metal ions. The ligand HL and metal complexes were tested against a strain of Gram +ve bacteria (Staphylococcus aureus, Gram −ve bacteria (Escherichia coli, and fungi (Candida albicans. The tested compounds exhibited high antibacterial activities.

  6. Synthesis, characterization and biological activities of Cu(II), Co(II), Mn(II), Fe(II), and UO2(VI) complexes with a new Schiff Base hydrazone: O-hydroxyacetophenone-7-chloro-4-quinoline hydrazone.

    Science.gov (United States)

    Al-Shaalan, Nora H

    2011-10-13

    The Schiff base hydrazone ligand HL was prepared by the condensation reaction of 7-chloro-4-quinoline with o-hydroxyacetophenone. The ligand behaves either as monobasic bidentate or dibasic tridentate and contain ONN coordination sites. This was accounted for be the presence in the ligand of a phenolic azomethine and imine groups. It reacts with Cu(II), Ni(II), Co(II), Mn(II), UO(2) (VI) and Fe(II) to form either mono- or binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, NMR, Mass, and UV-Visible spectra. The magnetic moments and electrical conductance of the complexes were also determined. The Co(II), Ni(II) and UO(2) (VI) complexes are mononuclear and coordinated to NO sites of two ligand molecules. The Cu(II) complex has a square-planar geometry distorted towards tetrahedral, the Ni(II) complex is octahedral while the UO(2) (VI) complex has its favoured heptacoordination. The Co(II), Mn(II) complexes and also other Ni(II) and Fe(III) complexes, which were obtained in the presence of Li(OH) as deprotonating agent, are binuclear and coordinated via the NNNO sites of two ligand molecules. All the binuclear complexes have octahedral geometries and their magnetic moments are quite low compared to the calculated value for two metal ions complexes and thus antiferromagnetic interactions between the two adjacent metal ions. The ligand HL and metal complexes were tested against a strain of Gram +ve bacteria (Staphylococcus aureus), Gram -ve bacteria (Escherichia coli), and fungi (Candida albicans). The tested compounds exhibited high antibacterial activities.

  7. Advanced experimental analysis of controls on microbial Fe(III) oxide reduction. First year progress report

    Energy Technology Data Exchange (ETDEWEB)

    Roden, E.E.; Urrutia, M.M.

    1997-07-01

    'The authors have made considerable progress toward a number of project objectives during the first several months of activity on the project. An exhaustive analysis was made of the growth rate and biomass yield (both derived from measurements of cell protein production) of two representative strains of Fe(III)-reducing bacteria (Shewanellaalga strain BrY and Geobactermetallireducens) growing with different forms of Fe(III) as an electron acceptor. These two fundamentally different types of Fe(III)-reducing bacteria (FeRB) showed comparable rates of Fe(III) reduction, cell growth, and biomass yield during reduction of soluble Fe(III)-citrate and solid-phase amorphous hydrous ferric oxide (HFO). Intrinsic growth rates of the two FeRB were strongly influenced by whether a soluble or a solid-phase source of Fe(III) was provided: growth rates on soluble Fe(III) were 10--20 times higher than those on solid-phase Fe(III) oxide. Intrinsic FeRB growth rates were comparable during reduction of HF0 and a synthetic crystalline Fe(III) oxide (goethite). A distinct lag phase for protein production was observed during the first several days of incubation in solid-phase Fe(III) oxide medium, even though Fe(III) reduction proceeded without any lag. No such lag between protein production and Fe(III) reduction was observed during growth with soluble Fe(III). This result suggested that protein synthesis coupled to solid-phase Fe(III) oxide reduction in batch culture requires an initial investment of energy (generated by Fe(III) reduction), which is probably needed for synthesis of materials (e.g. extracellular polysaccharides) required for attachment of the cells to oxide surfaces. This phenomenon may have important implications for modeling the growth of FeRB in subsurface sedimentary environments, where attachment and continued adhesion to solid-phase materials will be required for maintenance of Fe(III) reduction activity. Despite considerable differences in the rate and

  8. Functionalization of conducting polymer with novel Co(II) complex: Electroanalysis of ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Swati [School of Materials Science and Technology, Institute of Technology, Banaras Hindu University, Varanasi 221005 (India); Prakash, Rajiv, E-mail: rajivprakash12@yahoo.com [School of Materials Science and Technology, Institute of Technology, Banaras Hindu University, Varanasi 221005 (India)

    2010-06-15

    We report for the first time the functionalization of a conducting polymer with a metal complex in order to develop a new type of catalytic material exhibiting better electronic communication through their delocalized {pi} electrons. The Co(II) complex having hydroxyl group as functional moiety is chemically coupled with carboxyl group of polyanthranilic acid which itself is a self doped conducting polymer. The covalent linkage between Co(II) and -OH group is confirmed using UV-vis, FT-IR and NMR spectroscopic techniques. The Co(II) complex functionalized polymer does exhibit excellent redox behavior and stability with mixed properties of Co(II) complex and {pi}-conjugated polymer. The material possesses potential benefits in sensors/biosensor applications and it is demonstrated for the electroanalysis of ascorbic acid at a level of nano molar concentration.

  9. The novel approach to Cd(II) extraction by polymer inclusion membrane using TIOA as carrier

    Science.gov (United States)

    Polat, Cüneyt; Eyüpoǧlu, Volkan; Sara, Osman Nuri

    2016-04-01

    In the present study, the novel approach for the extraction of Cd(II) from acidic iodide solutions was achieved by using PVC based polymer inclusion membrane (PIM) technique containing triisooctyl amine (TIOA) as a carrier. PIMs were prepared according to the literature (1) and characterized by in aspects of thickness and surface morphology and molecular characterization. PIM composition was varied to find optimum membrane formation on Cd(II) transport. The effective parameters like thickness, plasticizer type and rate and carrier rate were investigated. Also, as a useful parameter, the concentration in the feed phase was examined to assess the effect on optimized membrane compositions. It was found that the concentration was the most useful parameter in the aqueous phase of Cd(II) transport because the remained I- in the aqueous feed phase unreacted with Cd(II). We recognize that by the time free I- concentration in the feed, the accumulation of the membrane increases and loading capacity of the membrane with CdI42- decreases because of the limited amount of carrier molecules in the PIM. As a result, it is concluded that extraction and separation of Cd(II) from simulated Ni/Cd leach solutions was carried out with higher initial mass transfer and permeation coefficients as 9,07×10-7 mol/m2s and 1,02×10-5 m/s at the optimum conditions respectively.

  10. Amylopectin-g-poly(methylacrylate-co-sodium acrylate): An efficient Cd(II) binder.

    Science.gov (United States)

    Sasmal, Dinabandhu; Kolya, Haradhan; Tripathy, Tridib

    2016-10-01

    Synthesis, characterization and Cd(II) adsorption studies of a novel biodegradable graft copolymer based on partially hydrolysed polymethylacrylate (PMA) grafted amylopectin was reported, which was prepared by first grafting of PMA chains onto the amylopectin backbone followed by partial alkaline hydrolysis. The hydrolysed graft copolymer (PHAP) was characterized by measuring saponification equivalent (SE), FTIR, (1)H NMR and (13)C NMR spectroscopy and thermal analysis (TG/DTG). The graft copolymer was biodegradable. Various operating variables affecting the metal sorption such as, amount of adsorbent, solution pH, contact time, temperature and Cd(II) solution concentration were studied which showed that the maximum adsorption of Cd(II) was found at pH 5.5, temperature 90°C, time 120min, polymer dose, 0.02g/L and initial Cd(II) concentration, 50mg/L. The adsorption data were well described by the pseudo-second-order and Langmuir isotherm model. Metal complexation studies were carried out experimentally using UV-visible, FTIR spectroscopy and theoretically using Density Functional Theory by Gaussian 09 and Gauss view 5.0 programmes which confirms a square planer geometry involving Cd(II) and COO(-) groups. Calculation of the various thermodynamic parameters was also done. The negative value of free energy change indicates the spontaneous nature of the adsorption.

  11. Esterified coir pith as an adsorbent for the removal of Co(II) from aqueous solution.

    Science.gov (United States)

    Parab, Harshala; Joshi, Shreeram; Shenoy, Niyoti; Lali, Arvind; Sarma, U S; Sudersanan, M

    2008-04-01

    Coir pith was chemically modified for the adsorption of cobalt(II) ions from aqueous solution. Chemical modification was done by esterification using succinic anhydride followed by activation with NaHCO(3) in order to improve the adsorption of Co(II). Adsorptive removal of Co(II) from aqueous solution onto modified coir pith was evaluated in batch studies under varying conditions of agitation time and metal ion concentration to assess the kinetic and equilibrium parameters. A pseudo-second-order kinetic model fitted well for the sorption of Co(II) onto modified coir pith. Sorption kinetics showed that the loading of Co(II) by this material was quite fast under ambient conditions. The Langmuir and Freundlich equilibrium isotherm models provided excellent fits for the adsorption data, with R(2) of 0.99 and 0.98, respectively. After esterification, the maximum Co(II) sorption loading Q(0); was greatly improved. It is evident that chemically modified adsorbent exhibits better Co(II) removal capability than raw adsorbent suggesting that surface modification of the adsorbent generates more adsorption sites on its solid surface for metal adsorption. A complete recovery of the adsorbed metal ions from the spent adsorbent was achieved by using 1.0N HCl.

  12. Pb(II) and Cd(II) removal from aqueous solutions by olive cake

    Energy Technology Data Exchange (ETDEWEB)

    Doyurum, Sabriye [Department of Chemistry, Faculty of Arts and Sciences, Celal Bayar University, Manisa 45140 (Turkey)]. E-mail: sabriyedoyurum@yahoo.com; Celik, Ali [Department of Chemistry, Faculty of Arts and Sciences, Celal Bayar University, Manisa 45140 (Turkey)

    2006-11-02

    The removal of heavy metals from wastewater using olive cake as an adsorbent was investigated. The effect of the contact time, pH, temperature, and concentration of adsorbate on adsorption performance of olive cake for Pb(II) and Cd(II) ions were examined by batch method. Adsorption of Pb(II) and Cd(II) in aqueous solution onto olive cake was studied in single component. After establishing the optimum conditions, elution of these ions from the adsorbent surface was also examined. The optimum sorption conditions were determined for two elements. Maximum desorption of the Pb(II) and Cd(II) ions were found to be 95.92 and 53.97% by 0.5 M HNO{sub 3} and 0.2 M HCl, respectively. The morphological analysis of the olive cake was performed by the scanning electron microscopy (SEM)

  13. Pb(II) and Cd(II) removal from aqueous solutions by olive cake.

    Science.gov (United States)

    Doyurum, Sabriye; Celik, Ali

    2006-11-02

    The removal of heavy metals from wastewater using olive cake as an adsorbent was investigated. The effect of the contact time, pH, temperature, and concentration of adsorbate on adsorption performance of olive cake for Pb(II) and Cd(II) ions were examined by batch method. Adsorption of Pb(II) and Cd(II) in aqueous solution onto olive cake was studied in single component. After establishing the optimum conditions, elution of these ions from the adsorbent surface was also examined. The optimum sorption conditions were determined for two elements. Maximum desorption of the Pb(II) and Cd(II) ions were found to be 95.92 and 53.97% by 0.5M HNO(3) and 0.2M HCl, respectively. The morphological analysis of the olive cake was performed by the scanning electron microscopy (SEM).

  14. Control of Fe(III) site occupancy on the rate and extent of microbial reduction of Fe(III) in nontronite

    Science.gov (United States)

    Jaisi, D.P.; Kukkadapu, R.K.; Eberl, D.D.; Dong, H.

    2005-01-01

    A quantitative study was performed to understand how Fe(III) site occupancy controls Fe(III) bioreduction in nontronite by Shewanella putrefaciens CN32. NAu-1 and NAu-2 were nontronites and contained Fe(III) in different structural sites with 16 and 23% total iron (w/w), respectively, with almost all iron as Fe(III). Mo??ssbauer spectroscopy showed that Fe(III) was present in the octahedral site in NAu-1 (with a small amount of goethite), but in both the tetrahedral and the octahedral sites in NAu-2. Mo??ssbauer data further showed that the octahedral Fe(III) in NAu-2 existed in at least two environments- trans (M1) and cis (M2) sites. The microbial Fe(III) reduction in NAu-1 and NAu-2 was studied in batch cultures at a nontronite concentration of 5 mg/mL in bicarbonate buffer with lactate as the electron donor. The unreduced and bioreduced nontronites were characterized by X-ray diffraction (XRD), Mo??ssbauer spectroscopy, and transmission electron microscopy (TEM). In the presence of an electron shuttle, anthraquinone-2,6-disulfonate (AQDS), the extent of bioreduction was 11%-16% for NAu-1 but 28%-32% for NAu-2. The extent of reduction in the absence of AQDS was only 5%-7% for NAu-1 but 14%-18% for NAu-2. The control experiments with heat killed cells and without cells did not show any appreciable reduction (crystal size distribution. The decrease in crystal size suggests reductive dissolution of nontronite NAu-2, which was supported by aqueous solution chemistry (i.e., aqueous Si). These data suggest that the more extensive Fe(III) bioreduction in NAu-2 was due to the presence of the tetrahedral and the trans-octahedral Fe(III), which was presumed to be more reducible. The biogenic Fe(II) was not associated with biogenic solids or in the aqueous solution. We infer that it may be either adsorbed onto surfaces of nontronite particles/bacteria or in the structure of nontronite. Furthermore, we have demonstrated that natural nontronite clays were capable of

  15. Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of Co(II)- picolinate complex

    Energy Technology Data Exchange (ETDEWEB)

    Tamer, Ömer, E-mail: omertamer@sakarya.edu.tr; Avcı, Davut; Atalay, Yusuf

    2015-11-15

    A cobalt(II) complex of picolinate was synthesized, and its structure was fully characterized by the applying of X-ray diffraction method as well as FT-IR, FT-Raman and UV–vis spectroscopies. In order to both support the experimental results and convert study to more advanced level, density functional theory calculations were performed by using B3LYP level. Single crystal X-ray structural analysis shows that cobalt(II) ion was located to the center of distorted octahedral geometry. The C=O, C=C and C=N stretching vibrations were found as highly active and strong peaks, inducing the molecular charge transfer within Co(II) complex. The small energy gap between frontier molecular orbital energies was another indicator of molecular charge transfer interactions within Co(II) complex. The nonlinear optical properties of Co(II) complex were investigated at DFT/B3LYP level, and the hypepolarizability parameter was found to be decreased due to the presence of inversion symmetry. The natural bond orbital (NBO) analysis was performed to investigate molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength for Co(II) complex. Finally, molecular electrostatic potential (MEP) and spin density distributions for Co(II) complex were evaluated. - Highlights: • Co(II) complex of picolinate was prepared. • Its FT-IR, FT-Raman and UV–vis spectra were measured. • DFT calculations were performed to support experimental results. • Small HOMO-LUMO energy gap is an indicator of molecular charge transfer. • Spin density localized on Co(II) as well as O and N atoms.

  16. Preparation, characterization of electrospun meso-hydroxylapatite nanofibers and their sorptions on Co(II)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hualin, E-mail: hlwang@hfut.edu.cn [School of Chemical Technology, Hefei University of Technology, Hefei, Anhui 230009 (China); Zhang, Peng; Ma, Xingkong; Jiang, Suwei; Huang, Yan; Zhai, Linfeng [School of Chemical Technology, Hefei University of Technology, Hefei, Anhui 230009 (China); Jiang, Shaotong [School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, Anhui 230009 (China)

    2014-01-30

    Highlights: • PVA/HA nanofibers could change into meso-HA nanofibers by calcination process. • Sorption of Co(II) on meso-HA was strongly dependent on pH and ionic strength. • Sorption kinetic data were well fitted by the pseudo-second-order rate equation. • Sorption isotherms could be well described by the Langmuir model. • Sorption process of Co(II) on meso-HA nanofibers was spontaneous and endothermic. -- Abstract: In this work, mesoporous hydroxylapatite (meso-HA) nanofibers were prepared via calcination process with polyvinyl alcohol/HA (PVA/HA) hybrid nanofibers fabricated by electrospinning technique as precursors, and the removal efficiency of meso-HA nanofibers toward Co(II) was evaluated via sorption kinetics and sorption isotherms. Furthermore, the sorption behaviors of Co(II) on meso-HA nanofibers were explored as a function of pH, ionic strength, and thermodynamic parameters. There existed hydrogen bonds between HA and PVA matrix in precursor nanofibers which could change into meso-HA nanofibers with main pore diameter at 27 nm and specific surface area at 114.26 m{sup 2}/g by calcination process. The sorption of Co(II) on meso-HA was strongly dependent on pH and ionic strength. Outer-sphere surface complexation or ion exchange was the main mechanisms of Co(II) adsorption on meso-HA at low pH, whereas inner-sphere surface complexation was the main adsorption mechanism at high pH. The sorption kinetic data were well fitted by the pseudo-second-order rate equation. The sorption isotherms could be well described by the Langmuir model. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) calculated from the temperature-dependent sorption isotherms suggested that the sorption process of Co(II) on meso-HA nanofibers was spontaneous and endothermic.

  17. Extraction of Co(II) from aqueous solution using emulsion liquid membrane.

    Science.gov (United States)

    Gasser, M S; El-Hefny, N E; Daoud, J A

    2008-03-01

    The extraction equilibrium of Co(II) from thiocyanate medium by CYANEX 923 (mixture of straight chain alkylated phosphine oxides) in cyclohexane was studied. The stoichiometry of the extraction reaction was postulated based on slope analysis method and the extraction constant Kex was calculated. The stripping percentage of Co(II) with sulphuric acid from the loaded CYANEX 923 was found to increase with the increase in acid concentration. The extraction of Co(II) from aqueous thiocyanate medium into emulsion liquid membrane using CYANEX 923 extractant was also studied. The influence of different parameters such as stirring speed, surfactant concentration, pH of the extractant phase, carrier concentration, internal phase stripping acid concentration, initial Co(II) concentration as well as temperature on the emulsion stability were investigated. The applicability of the emulsion liquid membrane (ELM) process using CYANEX 923 as extractant and SPAN 80 as surfactant for the removal and the concentration of Co(II) from thiocyanate solution was investigated. The results show that it is possible to recover 95% of cobalt in the inner phase after 10 min of contacting time with a concentration factor of 5.

  18. Enhanced removal of Cd(II) and Pb(II) by composites of mesoporous carbon stabilized alumina

    Science.gov (United States)

    Yang, Weichun; Tang, Qiongzhi; Wei, Jingmiao; Ran, Yajun; Chai, Liyuan; Wang, Haiying

    2016-04-01

    A novel adsorbent of mesoporous carbon stabilized alumina (MC/Al2O3) was synthesized through one-pot hard-templating method. The adsorption potential of MC/Al2O3 for Cd(II) and Pb(II) from aqueous solution was investigated compared with the mesoporous carbon. The results indicated the MC/Al2O3 showed excellent performance for Cd(II) and Pb(II) removal, the adsorption capacity reached 49.98 mg g-1 for Cd(II) with initial concentration of 50 mg L-1 and reached 235.57 mg g-1 for Pb(II) with initial concentration of 250 mg L-1, respectively. The kinetics data of Cd(II) adsorption demonstrated that the Cd(II) adsorption rate was fast, and the removal efficiencies with initial concentration of 10 and 50 mg L-1 can reach up 99% within 5 and 20 min, respectively. The pseudo-second-order kinetic model could describe the kinetics of Cd(II) adsorption well, indicating the chemical reaction was the rate-controlling step. The mechanism for Cd(II) and Pb(II) adsorption by MC/Al2O3 was investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectroscopy (FTIR), and the results indicated that the excellent performance for Cd(II) and Pb(II) adsorption of MC/Al2O3 was mainly attributed to its high surface area and the special functional groups of hydroxy-aluminum, hydroxyl, carboxylic through the formation of strong surface complexation or ion-exchange. It was concluded that MC/Al2O3 can be recognized as an effective adsorbent for removal of Cd(II) and Pb(II) in aqueous solution.

  19. Going wireless: Fe(III) oxide reduction without pili by Geobacter sulfurreducens strain JS-1.

    Science.gov (United States)

    Smith, Jessica A; Tremblay, Pier-Luc; Shrestha, Pravin Malla; Snoeyenbos-West, Oona L; Franks, Ashley E; Nevin, Kelly P; Lovley, Derek R

    2014-07-01

    Previous studies have suggested that the conductive pili of Geobacter sulfurreducens are essential for extracellular electron transfer to Fe(III) oxides and for optimal long-range electron transport through current-producing biofilms. The KN400 strain of G. sulfurreducens reduces poorly crystalline Fe(III) oxide more rapidly than the more extensively studied DL-1 strain. Deletion of the gene encoding PilA, the structural pilin protein, in strain KN400 inhibited Fe(III) oxide reduction. However, low rates of Fe(III) reduction were detected after extended incubation (>30 days) in the presence of Fe(III) oxide. After seven consecutive transfers, the PilA-deficient strain adapted to reduce Fe(III) oxide as fast as the wild type. Microarray, whole-genome resequencing, proteomic, and gene deletion studies indicated that this adaptation was associated with the production of larger amounts of the c-type cytochrome PgcA, which was released into the culture medium. It is proposed that the extracellular cytochrome acts as an electron shuttle, promoting electron transfer from the outer cell surface to Fe(III) oxides. The adapted PilA-deficient strain competed well with the wild-type strain when both were grown together on Fe(III) oxide. However, when 50% of the culture medium was replaced with fresh medium every 3 days, the wild-type strain outcompeted the adapted strain. A possible explanation for this is that the necessity to produce additional PgcA, to replace the PgcA being continually removed, put the adapted strain at a competitive disadvantage, similar to the apparent selection against electron shuttle-producing Fe(III) reducers in many anaerobic soils and sediments. Despite increased extracellular cytochrome production, the adapted PilA-deficient strain produced low levels of current, consistent with the concept that long-range electron transport through G. sulfurreducens biofilms is more effective via pili.

  20. Dissimilatory Fe(III) reduction by the marine microorganism Desulfuromonas acetoxidans

    Science.gov (United States)

    Roden, E.E.; Lovley, D.R.

    1993-01-01

    The ability of the marine microorganism Desulfuromonas acetoxidans to reduce Fe(III) was investigated because of its close phylogenetic relationship with the freshwater dissimilatory Fe(III) reducer Geobacter metallireducens. Washed cell suspensions of the type strain of D. acetoxidans reduced soluble Fe(III)-citrate and Fe(III) complexed with nitriloacetic acid. The c-type cytochrome(s) of D. acetoxidans was oxidized by Fe(III)- citrate and Mn(IV)-oxalate, as well as by two electron acceptors known to support growth, colloidal sulfur and malate. D. acetoxidans grew in defined anoxic, bicarbonate-buffered medium with acetate as the sole electron donor and poorly crystalline Fe(III) or Mn(IV) as the sole electron acceptor. Magnetite (Fe3O4) and siderite (FeCO3) were the major end products of Fe(III) reduction, whereas rhodochrosite (MnCO3) was the end product of Mn(IV) reduction. Ethanol, propanol, pyruvate, and butanol also served as electron donors for Fe(III) reduction. In contrast to D. acetoxidans, G. metallireducens could only grow in freshwater medium and it did not conserve energy to support growth from colloidal S0 reduction. D. acetoxidans is the first marine microorganism shown to conserve energy to support growth by coupling the complete oxidation of organic compounds to the reduction of Fe(III) or Mn(IV). Thus, D. acetoxidans provides a model enzymatic mechanism for Fe(III) or Mn(IV) oxidation of organic compounds in marine and estuarine sediments. These findings demonstrate that 16S rRNA phylogenetic analyses can suggest previously unrecognized metabolic capabilities of microorganisms.

  1. Tea Wastes Efficiency on Removal of Cd(II From Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Mehrdad Cheraghi

    2016-07-01

    Full Text Available Background & Aims of the Study: Heavy metals, such as cadmium (Cd(II, enter into the environment and cause health hazard due to their toxicity and bioaccumulation in the human body. Therefore, they must be removed from water. In recent years, much attention has been focused on the use of material residues as low-cost adsorbents for the removal of heavy metal ions from aqueous solutions. The aim of this paper is the assessment of tea wastes efficiency on removal of Cd(II from aqueous solutions. Materials and Methods: The present study was conducted in experimental scale. In this paper, tea wastes were prepared and used as an adsorbent for the removal of Cd(II ions from water. In batch tests, the effect of parameters like pH (1.0-8.0, initial metal concentration (100-800 mg L-1, contact time (15-120 min, adsorbent dose (1.0-5.0 g and temperature (25-55 °C on the adsorption process was studied. Results: The results demonstrated that the maximum percentage of Cd(II adsorption was found at pH 6.0 and the equilibrium was achieved after 60 min with 3.0 g tea wastes. The experimental isotherm data were analyzed, using the Langmuir and Freundlich models and it was found that the removal process followed the Langmuir isotherm. In addition, the adsorption kinetics followed the pseudo-second-order kinetic model. The maximum adsorption capacity calculated by Langmuir fitting was 71.4 mg g−1. Conclusion: The results suggest that tea wastes could be employed as an effective material for the removal of Cd(II ions from aqueous solutions and the maximum adsorption capacity was found to be 71.4 mg g−1.

  2. Dissimilatory Fe(III) Reduction by the Marine Microorganism Desulfuromonas acetoxidans

    OpenAIRE

    Roden, Eric E.; Lovley, Derek R.

    1993-01-01

    The ability of the marine microorganism Desulfuromonas acetoxidans to reduce Fe(III) was investigated because of its close phylogenetic relationship with the freshwater dissimilatory Fe(III) reducer Geobacter metallireducens. Washed cell suspensions of the type strain of D. acetoxidans reduced soluble Fe(III)-citrate and Fe(III) complexed with nitriloacetic acid. The c-type cytochrome(s) of D. acetoxidans was oxidized by Fe(III)-citrate and Mn(IV)-oxalate, as well as by two electron acceptors...

  3. Fe(III) solar light induced degradation of diethyl phthalate (DEP) in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Mailhot, G.; Caceres, J.; Malato, S.; Bolte, M.

    2003-07-01

    The degradation of diethyl phthalate (DEP) photoinduced by Fe(III) in aqueous solution has been investigated under solar irradiation in the CPC reactor at Plataforma Solar de Almeria. Hydroxyl radicals OH, responsible of the degradation, are formed via an intramolecular photo redox process in excited Fe(III) aqua complexes. For prolonged irradiations DEP and its photoproducts are completely mineralized due to the regeneration of the absorbing species and the continuous formation of OH radicals that confers a catalytic aspect to the process. Consequently, the degradation photoinduced by Fe(III) could be an efficient method of DEP removal from water. (Author) 28 refs.

  4. Effects of background electrolytes and ionic strength on enrichment of Cd(II) ions with magnetic graphene oxide-supported sulfanilic acid.

    Science.gov (United States)

    Hu, Xin-jiang; Liu, Yun-guo; Zeng, Guang-ming; You, Shao-hong; Wang, Hui; Hu, Xi; Guo, Yi-ming; Tan, Xiao-fei; Guo, Fang-ying

    2014-12-01

    To elucidate the influence mechanisms of background electrolytes and ionic strength on Cd(II) removal, the adsorption of Cd(II) onto magnetic graphene oxide-supported sulfanilic acid (MGO-SA) in aqueous solutions containing different types and concentrations of background electrolytes was studied. The results indicate that Cd(II) adsorption was strongly dependent on pH and could be strongly affected by background electrolytes and ionic strength. The Cd(II) removal was decreased with the presence of background electrolyte cations (Na(+), K(+), Ca(2+), Mg(2+), Mn(2+), Zn(2+), and Ni(2+)), and the divalent cations exerted more obvious influences on the Cd(II) uptake than the monovalent cations at pH 6. Both Cl(-) and NO3(-) had negative effects on Cd(II) adsorption because they can form water-soluble metal-anion complexes with Cd(II) ions. The presence of 0.01molL(-1) Na3PO4 reduced the removal percentage of Cd(II) at pH5. The Cd(II) adsorption was sensitive to changes in the concentration of NaCl, NaNO3, NaClO4, and Na3PO4. Besides, the adsorption isotherm of Cd(II) onto MGO-SA could be well described by the Freundlich model and was also influenced by the type of background electrolyte ions and the ionic strength.

  5. Sorption Characteristics of Aqueous Co(II) on Preformed Iron Ferrite Impregnated into Phenolsulphonic Formaldehyde Resin

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. J.; Kim, Y. K.

    2002-02-26

    A series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenolsulphonicformaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. The composite resin prepared by the above method shows stably high removal efficiency (maximally over 3.1 meq./gresin) to Co(II) species from wastewater in a wide range of solution pH. The wide range of applicable solution pH (i.e. pH 4.09 to 10.32) implies that the composite resin overcomes the limitations of the conventional ferrite process that is practically applicable only to alkaline conditions. It has been found that both ion exchange (by the organic resin constituent) and surface adsorption (by the inorganic adsorbent constituent) are major reaction mechanisms for removing Co(II) from wastewater, but surface precipitation results in the high sorption capacity to Co(II) beyond normal ion exchange capacity of the phenolsulphonic-formaldehyde resin. Standard enthalpy change derived from van't Hoff equation is 32.0 kJ{center_dot}mol-1 conforming to the typical range for chemisorption or ion exchange. In a wide range of equilibrium Co(II) concentration, the overall isotherm is qualitatively explained by the generalized adsorption isotherm concept proposed by McKinley. At the experimental conditions where the composite resin shows equivalent selectivity to Co(II) and other competing reagents (i.e. EDTA and Na), the ratios of Co(II) to other chemicals turn out to be 2:1 and 1:221, respectively. In addition, the selectivity of the PSF-F to Co(II) species is very high (about 72% of Co(II)-removal efficiency) even when the molar ratio of Co(II) to Ca(II) is 1:30. It is anticipated that the composite resin can also be used for column-operation with process-control by applying external magnetic field, since the rigid bead-type composite resin

  6. Tripodal phenylamine-based ligands and their CoII complexes.

    Science.gov (United States)

    Jones, Matthew B; MacBeth, Cora E

    2007-10-01

    The syntheses of two phenylamine-based ligand systems, N(o-PhNH(2))(3) and N(o-PhNHC(O)(i)Pr)(3), are reported. These ligands readily coordinate to Co(II) to form monomeric complexes. X-ray diffraction studies establish that the [N(o-PhNC(O)(i)Pr)(3)](3-) ligand stabilizes the Co(II) ion in a trigonal-monopyramidal coordination environment. The axial coordination site in this complex is accessible and, upon cyanide coordination, generates an electrochemically active species.

  7. Selection and characterization of DNA aptamers for the development of light-up biosensor to detect Cd(II).

    Science.gov (United States)

    Wang, Hongyan; Cheng, Hui; Wang, Jine; Xu, Lijun; Chen, Hongxia; Pei, Renjun

    2016-07-01

    In order to develop a facile, cost-effective and quick-testing light-up biosensor with excellent specificity for cadmium ions (Cd(II)) detection, a modified selection method based on target-induced release of strands was used to isolate aptamers of Cd (II) with high specificity. Circular Dichroism (CD) data confirmed that one of the selected aptamers underwent a distinct conformational change on addition of Cd (II). A biosensor for Cd(II) was developed based on the Cd(II)-induced release of fluorescence-labeled aptamer from complex with a quencher-labeled short complementary sequence. The sensing platform displayed a Cd(II) concentration-dependent increase of fluorescence intensity in the low micromolar range and had an excellent selectivity in the presence of various interfering metal ions. Such biosensor could potentially be used for the detection of Cd(II) in environmental samples.

  8. Release of 226Ra from uranium mill tailings by microbial Fe(III) reduction

    Science.gov (United States)

    Landa, E.R.; Phillips, E.J.P.; Lovley, D.R.

    1991-01-01

    Uranium mill tailings were anaerobically incubated in the presence of H2 with Alteromonas putrefaciens, a bacterium known to couple the oxidation of H2 and organic compounds to the reduction of Fe(III) oxides. There was a direct correlation between the extent of Fe(III) reduction and the accumulation of dissolved 226Ra. In sterile tailings in which Fe(III) was not reduced, there was negligible leaching of 226Ra. The behavior of Ba was similar to that of Ra in inoculated and sterile systems. These results demonstrate that under anaerobic conditions, microbial reduction of Fe(III) may result in the release of dissolved 226Ra from uranium mill tailings. ?? 1991.

  9. Intercalation of Coordinatively Unsaturated Fe(III) Ion within Interpenetrated Metal-Organic Framework MOF-5.

    Science.gov (United States)

    Holmberg, Rebecca J; Burns, Thomas; Greer, Samuel M; Kobera, Libor; Stoian, Sebastian A; Korobkov, Ilia; Hill, Stephen; Bryce, David L; Woo, Tom K; Murugesu, Muralee

    2016-06-01

    Coordinatively unsaturated Fe(III) metal sites were successfully incorporated into the iconic MOF-5 framework. This new structure, Fe(III) -iMOF-5, is the first example of an interpenetrated MOF linked through intercalated metal ions. Structural characterization was performed with single-crystal and powder XRD, followed by extensive analysis by spectroscopic methods and solid-state NMR, which reveals the paramagnetic ion through its interaction with the framework. EPR and Mössbauer spectroscopy confirmed that the intercalated ions were indeed Fe(III) , whereas DFT calculations were employed to ascertain the unique pentacoordinate architecture around the Fe(III) ion. Interestingly, this is also the first crystallographic evidence of pentacoordinate Zn(II) within the MOF-5 SBU. This new MOF structure displays the potential for metal-site addition as a framework connector, thus creating further opportunity for the innovative development of new MOF materials.

  10. Adsorption of Pb(II) and Cd(II) from aqueous solutions using titanate nanotubes prepared via hydrothermal method.

    Science.gov (United States)

    Xiong, Lin; Chen, Cheng; Chen, Qing; Ni, Jinren

    2011-05-30

    Titanate nanotubes (TNs) with specific surface areas of 272.31 m(2)g(-1) and pore volumes of 1.264 cm(3)g(-1) were synthesized by alkaline hydrothermal method. The TNs were investigated as adsorbents for the removal of Pb(II) and Cd(II) from aqueous solutions. The FT-IR analysis indicated that Pb(II) and Cd(II) adsorption were mainly ascribed to the hydroxyl groups in the TNs. Batch experiments were conducted by varying contact time, pH and adsorbent dosage. It was shown that the initial uptake of each metal ion was very fast in the first 5 min, and adsorption equilibrium was reached after 180 min. The adsorption of Pb(II) and Cd(II) were found to be maximum at pH in the range of 5.0-6.0. The adsorption kinetics of both metal ions followed the pseudo-second-order model. Equilibrium data were best fitted with the Langmuir isotherm model, and the maximum adsorption capacities of Pb(II) and Cd(II) were determined to be 520.83 and 238.61 mg g(-1), respectively. Moreover, more than 80% of Pb(II) and 85% of Cd(II) adsorbed onto TNs can be desorbed with 0.1M HCl after 3h. Thus, TNs were considered to be effective and promising materials for the removal of both Pb(II) and Cd(II) from wastewater.

  11. Adsorption of Co(II) by a carboxylate-functionalized polyacrylamide grafted lignocellulosics.

    Science.gov (United States)

    Shibi, I G; Anirudhan, T S

    2005-02-01

    A new adsorbent (PGBS-COOH) having carboxylate functional group at the chain end was synthesized by graft copolymerization of acrylamide onto banana stalk, BS (Musa Paradisiaca) using ferrous ammonium sulphate/H2O2 redox initiator system. The efficiency of the adsorbent in the removal of cobalt [Co(II)] from water was investigated using batch adsorption technique. The adsorbent exhibits very high adsorption potential for Co(II) and under optimum conditions more than 99% removal was achieved. The maximum adsorption capacity was observed at the pH range 6.5-9.0. The equilibrium isotherm data were analysed using three isotherm models, Langmuir, Freundlich and Scatchard, to determine the best fit equation for the sorption of Co(II) on the PGBS-COOH. A comparative study with a commercial cation exchanger, Ceralite IRC-50, having carboxylate functional group showed that PGBS-COOH is 2.8 times more effective compared to Ceralite IRC-50 at 30 degrees C. Synthetic nuclear power plant coolant water samples were also treated by the adsorbent to demonstrate its efficiency in removing Co(II) from water in the presence of other metal ions. Acid regeneration was tried for several cycles to recover the adsorbed metal ions and also to restore the sorbent to its original state.

  12. From discrete molecule, to polymer, to MOF: mapping the coordination chemistry of Cd(II) using (113)Cd solid-state NMR.

    Science.gov (United States)

    Frost, Jamie M; Kobera, Libor; Pialat, Amélie; Zhang, Yixin; Southern, Scott A; Gabidullin, Bulat; Bryce, David L; Murugesu, Muralee

    2016-08-23

    Studies of three related Cd(II) systems (a discrete [Cd(II)2] unit, a one-dimensional [Cd(II)2]n coordination polymer and a Cd(II)-based MOF) all derived from the ligand 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine, reveal an exceptionally rare example of (113)Cd-(113)Cd J coupling in the polymer that is detectable by solid-state NMR ((2)JCd-Cd = ∼65 Hz).

  13. Synthesis, characterization, biological activity and DNA cleavage studies of tridentate Schiff bases and their Co(II complexes

    Directory of Open Access Journals (Sweden)

    P. Kavitha

    2016-01-01

    Full Text Available In the present study a series of Co(II complexes of formyl chromone Schiff bases have been synthesized characterized by analytical, molar conductance, IR, electronic, magnetic susceptibility, thermal, fluorescence and powder XRD measurements and screened for various biological activities (antimicrobial, antioxidant, nematicidal, DNA cleavage and cytotoxicity. In all the Co(II complexes 1:2 metal to ligand molar ratio was obtained from analytical data. The molar conductance data confirm that all complexes are non-electrolytic in nature. Based on the electronic and magnetic data, an octahedral geometry is ascribed for all the Co(II complexes. Thermal behaviour of the synthesized complexes illustrates the general decomposition patterns of the complexes. The X-ray analysis data show that all the Co(II complexes have triclinic crystal system with different unit cell parameters. Metal complexes have greater antimicrobial activity than ligands. Antioxidant and nematicidal activities indicate that the ligands exhibit greater activity when compared to their respective Co(II complexes. All ligands and Co(II complexes of HL1 and HL2 showed considerable anticancer activity against Raw, MCF-7 and COLO 205 cell lines. All ligands and their Co(II complexes showed more pronounced DNA cleavage activity in the presence of H2O2.

  14. Enhanced removal of Cd(II) and Pb(II) by composites of mesoporous carbon stabilized alumina

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Weichun [Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Lushan South Road 932, Changsha 410017 (China); Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Lushan South Road 932, Changsha 410017 (China); Tang, Qiongzhi; Wei, Jingmiao; Ran, Yajun [Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Lushan South Road 932, Changsha 410017 (China); Chai, Liyuan [Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Lushan South Road 932, Changsha 410017 (China); Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Lushan South Road 932, Changsha 410017 (China); Wang, Haiying, E-mail: haiyw25@163.com [Department of Environmental Engineering, School of Metallurgy and Environment, Central South University, Lushan South Road 932, Changsha 410017 (China); Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution, Lushan South Road 932, Changsha 410017 (China)

    2016-04-30

    Graphical abstract: - Highlights: • Mesoporous carbon stabilized alumina was prepared by one-pot hard-templating method. • MC/Al{sub 2}O{sub 3} showed excellent performance for Cd(II) and Pb(II) adsorption. • Enhanced adsorption was due to the high surface area and special functional groups. - Abstract: A novel adsorbent of mesoporous carbon stabilized alumina (MC/Al{sub 2}O{sub 3}) was synthesized through one-pot hard-templating method. The adsorption potential of MC/Al{sub 2}O{sub 3} for Cd(II) and Pb(II) from aqueous solution was investigated compared with the mesoporous carbon. The results indicated the MC/Al{sub 2}O{sub 3} showed excellent performance for Cd(II) and Pb(II) removal, the adsorption capacity reached 49.98 mg g{sup −1} for Cd(II) with initial concentration of 50 mg L{sup −1} and reached 235.57 mg g{sup −1} for Pb(II) with initial concentration of 250 mg L{sup −1}, respectively. The kinetics data of Cd(II) adsorption demonstrated that the Cd(II) adsorption rate was fast, and the removal efficiencies with initial concentration of 10 and 50 mg L{sup −1} can reach up 99% within 5 and 20 min, respectively. The pseudo-second-order kinetic model could describe the kinetics of Cd(II) adsorption well, indicating the chemical reaction was the rate-controlling step. The mechanism for Cd(II) and Pb(II) adsorption by MC/Al{sub 2}O{sub 3} was investigated by X-ray photoelectron spectroscopy (XPS) and Fourier transformed infrared spectroscopy (FTIR), and the results indicated that the excellent performance for Cd(II) and Pb(II) adsorption of MC/Al{sub 2}O{sub 3} was mainly attributed to its high surface area and the special functional groups of hydroxy-aluminum, hydroxyl, carboxylic through the formation of strong surface complexation or ion-exchange. It was concluded that MC/Al{sub 2}O{sub 3} can be recognized as an effective adsorbent for removal of Cd(II) and Pb(II) in aqueous solution.

  15. Cd(II) removal and recovery enhancement by using acrylamide–titanium nanocomposite as an adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Ajit; Lee, Byeong-Kyu, E-mail: bklee@ulsan.ac.kr

    2014-09-15

    Graphical abstract: - Highlights: • Acrylamide doping initiated 10–20% increase in the particle size. • R-NH{sub 2}Cd{sup 2+} and Cd-O onto the nanocomposite improved Cd(II) adsorption. • Coexisting cations did not make any significant interference of Cd(II) removal. • Increased Ti nanoparticles leads to decrease in mass swelling of acrylamide. - Abstract: Acrylamide (AM) was in-situ doped into titanium during sol–gel reaction and used as an adsorbent for cadmium removal from aqueous solution. The resulting TiO{sub 2}-AM nanocomposite was characterized by particle size distribution (PSD) and thermogravimetric analysis (TGA). After cadmium adsorption, the nanocomposite was also characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and X-ray photoelectron spectroscopy (XPS) analyses. The adsorption behavior of the nanocomposite was examined by kinetic and equilibrium studies in batch conditions. The maximum cadmium binding capacity of TiO{sub 2}-AM was 322.58 mg g{sup −1} at an optimum pH of 8.0, compared to 86.95 mg g{sup −1} for nano-titanium. Cadmium sorption showed pseudo-second-order kinetics with a rate constant of 4.0 × 10{sup −4} and 9.4 × 10{sup −5} g mg{sup −1} min{sup −1} at an initial Cd(II) concentration of 100 and 500 mg L{sup −1}, respectively. Cd (II) adsorption interference of cations (Pb{sup 2+}, Cu{sup 2+}, Co{sup 2+} and Zn{sup +2}) and anions (Cl{sup −}, SO{sub 4}{sup 2−}, CO{sub 3}{sup 2−}) at pH 8 was very nominal because of favorable complex formation of Cd(II) and amide. The Cd(II) adsorption of 27% that was achieved in the fifth cycle was regenerated with 0.05 N acidic solutions.

  16. Iron Isotope Fractionations Reveal a Finite Bioavailable Fe Pool for Structural Fe(III) Reduction in Nontronite.

    Science.gov (United States)

    Shi, Bingjie; Liu, Kai; Wu, Lingling; Li, Weiqiang; Smeaton, Christina M; Beard, Brian L; Johnson, Clark M; Roden, Eric E; Van Cappellen, Philippe

    2016-08-16

    We report on stable Fe isotope fractionation during microbial and chemical reduction of structural Fe(III) in nontronite NAu-1. (56)Fe/(54)Fe fractionation factors between aqueous Fe(II) and structural Fe(III) ranged from -1.2 to +0.8‰. Microbial (Shewanella oneidensis and Geobacter sulfurreducens) and chemical (dithionite) reduction experiments revealed a two-stage process. Stage 1 was characterized by rapid reduction of a finite Fe(III) pool along the edges of the clay particles, accompanied by a limited release to solution of Fe(II), which partially adsorbed onto basal planes. Stable Fe isotope compositions revealed that electron transfer and atom exchange (ETAE) occurred between edge-bound Fe(II) and octahedral (structural) Fe(III) within the clay lattice, as well as between aqueous Fe(II) and structural Fe(III) via a transient sorbed phase. The isotopic fractionation factors decreased with increasing extent of reduction as a result of the depletion of the finite bioavailable Fe(III) pool. During stage 2, microbial reduction was inhibited while chemical reduction continued. However, further ETAE between aqueous Fe(II) and structural Fe(III) was not observed. Our results imply that the pool of bioavailable Fe(III) is restricted to structural Fe sites located near the edges of the clay particles. Blockage of ETAE distinguishes Fe(III) reduction of layered clay minerals from that of Fe oxyhydroxides, where accumulation of structural Fe(II) is much more limited.

  17. Spectroscopic properties of a series of Co(II) coordination polymers and the influence of Co(II) coordination environment on photoelectric property

    Science.gov (United States)

    Jin, Jing; Gong, Yuanyuan; Li, Lei; Han, Xiao; Meng, Qin; Liu, Yonghua; Niu, Shuyun

    2015-02-01

    Four Co(II) coordination polymers, [Co(suc)]n1, [Co(pdc)]n2, {[Co7(suc)4(OH)6(H2O)3] · 8H2O}n3, {[Co(bdc)(phen)(H2O)] · H2O}n4 (H2suc = succinic acid, H2pdc = pyridine-3,4-dicarboxylic acid, H2bdc = 1,2-benzenedicarboxylic acid, phen = 1,10-phenanthroline) were hydrothermally synthesized and characterized by X-ray single-crystal diffraction, surface photovoltage spectroscopy (SPS), electrical conductivity, thermogravimetric analysis (TG), ultraviolet visible and near-infrared absorption spectrum (UV-Vis-NIR), infrared spectrum (IR), and elemental analysis. The structural analyses indicate that the coordination numbers of the Co(II) ions are 4, 5, 6 and 6 for the polymers 1-4, respectively. And polymers 1 and 2 exhibit 3D structure formed by suc2- and pdc2- anions bridging Co(II) ions, respectively. Polymer 3 exhibits a 2D structure with suc2- anions bridging seven-nuclear [Co7(OH)6(H2O)3]3- unit and polymer 4 is a 1D structure bridged by bdc2- anions. The surface photoelectric properties of the cobalt polymers were mainly studied by SPS. The results of SPS reveal that all polymers possess certain photoelectric conversion property in the range of 300-800 nm. The influences of the structure, coordination micro-environment of central metal ion and structural dimensionality on response bands of SPS were discussed.

  18. Relative abundance of chemical forms of Cu(II) and Cd(II) on soybean roots as influenced by pH, cations and organic acids

    Science.gov (United States)

    Zhou, Qin; Liu, Zhao-Dong; Liu, Yuan; Jiang, Jun; Xu, Ren-Kou

    2016-11-01

    Little information is available on chemical forms of heavy metals on integrate plant roots. KNO3 (1 M), 0.05M EDTA at pH6 and 0.01 M HCl were used sequentially to extract the exchangeable, complexed and precipitated forms of Cu(II) and Cd(II) from soybean roots and then to investigate chemical form distribution of Cu(II) and Cd(II) on soybean roots. Cu(II) and Cd(II) adsorbed on soybean roots were mainly exchangeable form, followed by complexed form, while their precipitated forms were very low under acidic conditions. Soybean roots had a higher adsorption affinity to Cu(II) than Cd(II), leading to higher toxic of Cu(II) than Cd(II). An increase in solution pH increased negative charge on soybean and thus increased exchangeable Cu(II) and Cd(II) on the roots. Ca2+, Mg2+ and NH4+ reduced exchangeable Cu(II) and Cd(II) levels on soybean roots and these cations showed greater effects on Cd(II) than Cu(II) due to greater adsorption affinity of the roots to Cu(II) than Cd(II). L-malic and citric acids decreased exchangeable and complexed Cu(II) on soybean roots. In conclusion, Cu(II) and Cd(II) mainly existed as exchangeable and complexed forms on soybean roots. Ca2+ and Mg2+ cations and citric and L-malic acids can potentially alleviate Cu(II) and Cd(II) toxicity to plants.

  19. Bioavailability of Fe(III) in natural soils and the impact on mobility of inorganic contaminants

    Energy Technology Data Exchange (ETDEWEB)

    Kosson, David S.; Cowan, Robert M.; Young, Lily Y.; Hacherl, Eric L.; Scala, David J.

    2002-10-03

    Inorganic contaminants, such as heavy metals and radionuclides, can adhere to insoluble Fe(III) minerals resulting in decreased mobility of these contaminants through subsurface environments. Dissimilatory Fe(III)-reducing bacteria (DIRB), by reducing insoluble Fe(III) to soluble Fe(II), may enhance contaminant mobility. The Savannah River Site, South Carolina (SRS), has been subjected to both heavy metal and radionuclide contamination. The overall objective of this project is to investigate the release of inorganic contaminants such as heavy metals and radionuclides that are bound to solid phase soil Fe complexes and to elucidate the mechanisms for mobilization of these contaminants that can be associated with microbial Fe(III) reduction. This is being accomplished by (i) using uncontaminated and contaminated soils from SRS as prototype systems, (ii) evaluating the diversity of DIRBs within the samples and isolating cultures for further study, (iii) using batch microcosms to evaluate the bioavailability of Fe(III) from pure minerals and SRS soils, (iv) developing kinetic and mass transfer models that reflect the system dynamics, and (v) carrying out soil column studies to elucidate the dynamics and interactions amongst Fe(III) reduction, remineralization and contaminant mobility.

  20. Batch adsorptive removal of Fe(III, Cu(II and Zn(II ions in aqueous and aqueous organic–HCl media by Dowex HYRW2-Na Polisher resin as adsorbents

    Directory of Open Access Journals (Sweden)

    Abdul-Aleem Soliman Aboul-Magd

    2016-09-01

    Full Text Available Of the metal ions in tap, Nile, waste and sea water samples and some ores were carried out. Removal of heavy metal ions such as Fe(III, Cd(II, Zn(II, Cu(II, Mn(II, Mg(II, and Pb(II from water and wastewater is obligatory in order to avoid water pollution. Batch shaking adsorption experiments to evaluate the performance of nitric and hydrochloric acid solutions in the removal of metal ions by cation exchange resin at the same conditions for both, such as the effect of initial metal ion concentration, different proportions of some organic solvents, H+-ion concentrations and reaction temperature on the partition coefficients. The metal adsorption for the cation exchanger was found to be significant in different media for both nitric and hydrochloric acids, i.e., the adsorption up take of metal ions presented in this work is very significant depending on the characteristics of ions and on the external concentrations of solute. The presence of low ionic strength or low concentration of acids does have a significant adsorption of metal ions on ion-exchange resin. The results show that the ion exchanger could be employed for the preconcentration, separation and the determination.

  1. Microbial removal of Fe(III) impurities from clay using dissimilatory iron reducers.

    Science.gov (United States)

    Lee, E Y; Cho, K S; Ryu, H W; Chang, Y K

    1999-01-01

    Fe(III) impurities, which detract refractoriness and whiteness from porcelain and pottery, could be biologically removed from low-quality clay by indigenous dissimilatory Fe(III)-reducing microorganisms. Insoluble Fe(III) in clay particles was leached out as soluble Fe(II), and the Fe(III) reduction reaction was coupled to the oxidation of sugars such as glucose, maltose and sucrose. A maximum removal of 44-45% was obtained when the relative amount of sugar was 5% (w/w; sugar/clay). By the microbial treatment, the whiteness of the clay was increased from 63.20 to 79.64, whereas the redness was clearly decreased from 13.47 to 3.55.

  2. Stimulated anoxic biodegradation of aromatic hydrocarbons using Fe(III) ligands

    Science.gov (United States)

    Lovley, D.R.; Woodward, J.C.; Chapelle, F.H.

    1994-01-01

    Contamination of ground waters with water-soluble aromatic hydrocarbons, common components of petroleum pollution, often produces anoxic conditions under which microbial degradation of the aromatics is slow. Oxygen is often added to contaminated ground water to stimulate biodegradation, but this can be technically difficult and expensive. Insoluble Fe(III) oxides, which are generally abundant in shallow aquifers, are alternative potential oxidants, but are difficult for microorganisms to access. Here we report that adding organic ligands that bind to Fe(III) dramatically increases its bioavailability, and that in the presence of these ligands, rates of degradation of aromatic hydrocarbons in anoxic aquifer sediments are comparable to those in oxic sediments. We find that even benzene, which is notoriously refractory in the absence of oxygen, can be rapidly degraded. Our results suggest that increasing the bioavailability of Fe(III) by adding suitable ligands provides a potential alternative to oxygen addition for the bioremediation of petroleum-contaminated aquifers.Contamination of ground waters with water-soluble aromatic hydrocarbons, common components of petroleum pollution, often produces anoxic conditions under which microbial degradation of the aromatics is slow. Oxygen is often added to contaminated ground water to stimulate biodegradation, but this can be technically difficult and expensive. Insoluble Fe(III) oxides, which are generally abundant in shallow aquifers, are alternative potential oxidants, but are difficult for microorganisms to access. Here we report that adding organic ligands that bind to Fe(III) dramatically increases its bioavailability, and that in the presence of these ligands, rates of degradation of aromatic hydrocarbons in anoxic aquifer sediments are comparable to those in oxic sediments. We find that even benzene, which is notoriously refractory in the absence of oxygen, can be rapidly degraded. Our results suggest that increasing

  3. Origin of the Magnetic Anisotropy in Heptacoordinate Ni-II and Co-II Complexes

    NARCIS (Netherlands)

    Ruamps, Renaud; Batchelor, Luke J.; Maurice, Remi; Gogoi, Nayanmoni; Jimenez-Lozano, Pablo; Guihery, Nathalie; de Graaf, Coen; Barra, Anne-Laure; Sutter, Jean-Pascal; Mallah, Talal

    2013-01-01

    The nature and magnitude of the magnetic anisotropy of heptacoordinate mononuclear NiII and CoII complexes were investigated by a combination of experiment and ab initio calculations. The zero-field splitting (ZFS) parameters D of [Ni(H2DAPBH)(H2O)2](NO3)2.2?H2O (1) and [Co(H2DAPBH)(H2O)(NO3)](NO3)

  4. Molecular Underpinnings of Fe(III Oxide Reduction by Shewanella oneidensis MR-1

    Directory of Open Access Journals (Sweden)

    Liang eShi

    2012-02-01

    Full Text Available In the absence of O2 and other electron acceptors, the Gram-negative bacterium Shewanella oneidensis MR-1 can use ferric [Fe(III] (oxy(hydroxide minerals as the terminal electron acceptors for anaerobic respiration. At circumneutral pH and in the absence of strong complexing ligands, Fe(III oxides are relatively insoluble and thus are external to the bacterial cells. S. oneidensis MR-1 has evolved the machinery (i.e., metal-reducing or Mtr pathway for transferring electrons across the entire cell envelope to the surface of extracellular Fe(III oxides. The protein components identified to date for the Mtr pathway include CymA, MtrA, MtrB, MtrC and OmcA. CymA is an inner-membrane tetraheme c-type cytochrome (c-Cyt that is proposed to oxidize the quinol in the inner-membrane and transfers the released electrons to redox proteins in the periplasm. Although the periplasmic proteins receiving electrons from CymA during Fe(III oxidation have not been identified, they are believed to relay the electrons to MtrA. A decaheme c-Cyt, MtrA is thought to be embedded in the trans outer-membrane and porin-like protein MtrB. Together, MtrAB deliver the electrons across the outer-membrane to the MtrC and OmcA on the outmost bacterial surface. Functioning as terminal reductases, the outer membrane and decaheme c-Cyts MtrC and OmcA can bind the surface of Fe(III oxides and transfer electrons directly to these minerals. To increase their reaction rates, MtrC and OmcA can use the flavins secreted by S. oneidensis MR-1 cells as diffusible co-factors for reduction of Fe(III oxides. MtrC and OmcA can also serve as the terminal reductases for soluble forms of Fe(III. Although our understanding of the Mtr pathway is still far from complete, it is the best characterized microbial pathway used for extracellular electron exchange. Characterizations of the Mtr pathway have made significant contributions to the molecular understanding of microbial reduction of Fe(III oxides.

  5. Removal of Co(II) from aqueous solutions by sulfonated magnetic multi-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Juanjuan; Dong, Yunhui; Li, Jun; Min, Fanlian; Li, Yueyun [Shandong University of Technology, Zibo (China); Liu, Zhengjie [Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui (China)

    2015-11-15

    Sulfonated magnetic multi-walled carbon nanotubes (SMMWCNTs) were applied in the sorption of Co(II) from aqueous solutions. The SMMWCNTs were prepared and characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR), and X-ray diffractometer (XRD) test. A large number of influencing factors to the sorption process were investigated, such as pH, ionic strength, contact time, cations, anions, humic acid (HA), fulvic acid (FA) and temperature. The results indicated that the Co(II) sorption was strongly controlled by the pH and ionic strength. Moreover, foreign anions, such as F−, Cl{sup -} and Br{sup -}, had an obvious effect on the sorption process, which depended on the electronegativity of the anions. On the other hand, cations restrained sorption strongly, such as Mg{sup 2+} and Ca{sup 2+}. The existence of HA/FA enhanced sorption process at pH<8 while weakened at pH>8. As revealed by the sorption results, the Langmuir adsorption model was more favorable than the Freundlich adsorption model, and the pseudo-second-order model could fit the data much better than the pseudo-first-order. The thermodynamic analysis suggested that sorption was spontaneous and endothermic. What's more, the stability experiments of the SMMWCNTs showed that SMMWCNTs could maintain excellent magnetic stability and dispersion stability. Thus, this SMMWCNTs sorben was believed to be a promising material for the selective removal of Co(II) from heavy metal-containing wastewater.

  6. Magnetic anisotropy of a Co-II single ion magnet with distorted trigonal prismatic coordination

    DEFF Research Database (Denmark)

    Peng, Yan; Bodenstein, Tilmann; Fink, Karin

    2016-01-01

    The single ion magnetic properties of Co(II) are affected by the details of the coordination geometry of the ion. Here we show that a geometry close to trigonal prismatic which arises when the ligand 6,6'-((1Z)-((piperazine-1,4-diylbis(propane-3,1-diyl)) bis(azanylylidene)) bis(methanylylidene)) ......The single ion magnetic properties of Co(II) are affected by the details of the coordination geometry of the ion. Here we show that a geometry close to trigonal prismatic which arises when the ligand 6,6'-((1Z)-((piperazine-1,4-diylbis(propane-3,1-diyl)) bis(azanylylidene)) bis......(methanylylidene)) bis(2-methoxyphenol) coordinates to Co(II) does indeed lead to enhanced single-ion behaviour as has previously been predicted. Synthesis of the compound, structural information, and static as well as dynamic magnetic data are presented along with an analysis using quantum chemical ab initio...

  7. Synthesis, crystal structure and photo luminescent property of a 3D metal-organic hybrid of Cd(II) constructed by two different bridging carboxylate

    Indian Academy of Sciences (India)

    Biswajit Bhattacharya; Rajdip Dey; Debajyoti Ghoshal

    2013-05-01

    A solvothermal reaction of cadmium (II) nitrate with succinic acid and isonicotinic acid creates a novel 3D metal-organic framework, [Cd3(isonicotinate)2(suc)2] (1). Single crystal X-ray structure determination reveals that complex 1 posses two crystallographically independent Cd(II) centres. The succinate anion acts here as a heptadented ligand and binds five Cd(II) centre simultaneously. The heptacoordinated Cd(II) centres are oxo-bridged by succinate moiety and the hexacoordinated metal centres are terminally connected through four different succinate moiety to make the overall 2D sheet arrangement. In unit cell, the ratio of hexadented Cd(II) and heptadented Cd(II) is 1:2. The new compound was also characterized by luminescence spectra and compared with the luminescence spectra of the pure isonicotinic acid.

  8. Cd(II) complexes with different nuclearity and dimensionality based on 3-hydrazino-4-amino-1,2,4-triazole

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Cai-Xia; Zhang, Jian-Guo, E-mail: zjgbit@bit.edu.cn; Yin, Xin; Jin, Xin; Li, Tong; Zhang, Tong-Lai; Zhou, Zun-Ning

    2015-03-15

    A series of zero- to two-dimensional Cd(II) coordination compounds have been synthesized by the reaction of Cd(II) salts and 3-hydrazino-4-amino-1,2,4-triazole di-hydrochloride (HATr·2HCl). [CdCl{sub 2}(HATr){sub 2}] (1) and [Cd{sub 2}Cl{sub 4}(HATr){sub 2}(H{sub 2}O){sub 2}] (2) have discrete mononuclear and binuclear structures, respectively. [Cd(HATr){sub 2}(ClO{sub 4}){sub 2}]{sub n} (3) presents polymeric 1-D chain and [Cd{sub 2}(NO{sub 3}){sub 2}Cl{sub 2}(HATr){sub 2}]{sub n} (4) shows 2-D frameworks. All Cd(II) ions exhibit distorted octahedral configurations in 1–3, whilst both hexa and heptacoordinated Cd(II) are formed in 4. The HATr ligands adopt chelating coordinated mode in 1, while tri-dentate bridging–chelating mode in 2–4. The chloride ion is a mono-coordinated ligand in 1 and 2, but it bridges two adjacent metal ions in 4. Furthermore, thermal behaviors have been investigated and the results reveal that all complexes have good thermal stability. The impact sensitivity test indicates that complex 3 is sensitive to impact stimuli. - Graphical abstract: Four Cd(II) complexes based on 3-hydrazino-4-amino-1,2,4-triazole ligands exhibit diverse structures from mononuclear to 2D networks. - Highlights: • Cd(II) complexes containing 3-hydrazino-4-amino-1,2,4-triazole ligands. • Mononuclear, binuclear, 1-D and 2-D structures. • Good thermal stability. • Thermal decomposition kinetics.

  9. Adsorption and desorption of Cd(II) onto titanate nanotubes and efficient regeneration of tubular structures

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ting; Liu, Wen; Xu, Nan [Shenzhen Key Laboratory for Heavy Metal Pollution Control and Reutilization, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055 (China); Ni, Jinren, E-mail: nijinren@iee.pku.edu.cn [Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871 (China)

    2013-04-15

    Highlights: ► Satisfactory reuse of TNTs due to easy regeneration of tubular structures. ► TNTs regeneration using only 2% of NaOH needed for virgin TNTs preparation. ► Excellent regeneration attributed to steady TNTs skeleton and complex form of TNTs-OCd{sup +}OH{sup −} onto adsorbed TNTs. -- Abstract: Efficient regeneration of desorbed titanate nanotubes (TNTs) was investigated with cycled Cd(II) adsorption and desorption processes. After desorption of Cd (II) from TNTs using 0.1 M HNO{sub 3}, regeneration could be simply achieved with only 0.2 M NaOH at ambient temperature, i.e. 2% of the NaOH needed for virgin TNTs preparation at 130 °C. The regenerated TNTs displayed similar adsorption capacity of Cd(II) even after six recycles, while significant reduction could be detected for desorbed TNTs without regeneration. The virgin TNTs, absorbed TNTs, desorbed TNTs and regenerated TNTs were systematically characterized. As results, the ion-exchange mechanism with Na{sup +} in TNTs was convinced with obvious change of -TiO(ONa){sub 2} by FTIR spectroscopy. The easy recovery of the damaged tubular structures proved by TEM and XRD was ascribed to asymmetric distribution of H{sup +} and Na{sup +} on the surface side and interlayer region of TNTs. More importantly, the cost-effective regeneration was found possibly related to complex form of TNTs-OCd{sup +}OH{sup −} onto the adsorbed TNTs, which was identified with help of X-ray photoelectron spectroscopy, and further indicated due to high relevance to an unexpected mole ratio of 1:1 between exchanged Na{sup +} and absorbed Cd(II)

  10. Ternary biosorption studies of Cd(II), Cr(III) and Ni(II) on shelled Moringa oleifera seeds.

    Science.gov (United States)

    Sharma, Parul; Kumari, Pushpa; Srivastava, M M; Srivastava, Shalini

    2007-01-01

    Competitive biosorption of Cd(II), Cr(III) and Ni(II) on unmodified shelled Moringa oleifera seeds (SMOS) present in ternary mixture were compared with the single metal solution. The extent of adsorption capacity of the ternary metal ions tested on unmodified SMOS was low (10-20%) as compared to single metal ions. SMOS removed the target metal ions in the selectivity order of Cd(II) > Cr(III) > Ni(II). Sorption equilibria, calculated from adsorption data, explained favorable performance of biosorption system. Regeneration of exhausted biomass was also attempted for several cycles with a view to restore the sorbent to its original state.

  11. Influence of geochemical properties and land-use types on the microbial reduction of Fe(III) in subtropical soils.

    Science.gov (United States)

    Liu, Chengshuai; Wang, Yongkui; Li, Fangbai; Chen, Manjia; Zhai, Guangshu; Tao, Liang; Liu, Chuanping

    2014-08-01

    Microbial Fe(III) reduction significantly impacts the geochemical processes and the composition of most subsurface soils. However, up to now, the factors influencing the efficiency of Fe(III) reduction in soils have not been fully described. In this study, soil Fe(III) reduction processes related to geochemical properties and land-use types were systematically investigated using iron-rich soils. The results showed that microbial Fe(III) reduction processes were efficient and their rates varied significantly in different types of soils. Fe(III) reduction rates were 1.1-5.6 times as much in soils with glucose added as in those without glucose. Furthermore, Fe(III) reduction rates were similar in soils from the same parent materials, while they were highest in soils developed from sediments, with a mean rate of 1.87 mM per day when supplemented with glucose. In addition, the Fe(III) reduction rates, reaching 0.99 and 0.59 mM per day on average with and without glucose added, respectively, were higher in the paddy soils affected heavily by human activities than those in the forest soils (average rates of 0.38 and 0.15 mM per day when with and without glucose, respectively). All the soil weathering indices correlated linearly with Fe(III) reduction rates, even though the reduction of iron in soils with higher weathering degrees was partly inhibited by a higher soil protonation trend and fewer available iron reduction sites in the soils, which gives lower reduction rates. These results clearly illustrate that soil Fe(III) reduction rates are greatly dependent on soil geochemical properties and land-use types and help define which soil types exhibit similar degrees of Fe(III) reduction under field conditions.

  12. Kinetics of microbial Fe(III) oxyhydroxidereduction: The role of mineral properties

    NARCIS (Netherlands)

    Bonneville, Steeve

    2005-01-01

    In many soils, sediments and groundwaters, ferric iron is a major potential electron acceptor for the oxidation of organic matter. In contrast to other terminal electron acceptors (e.g. nitrate or sulfate), the concentration of Fe3+(aq), is limited by the low solubility of Fe(III) oxyhydroxides un

  13. Kinetics of microbial Fe(III) oxyhydroxide reduction : The role of mineral properties

    NARCIS (Netherlands)

    Bonneville, S.C.

    2005-01-01

    In many soils, sediments and groundwaters, ferric iron is a major potential electron acceptor for the oxidation of organic matter. In contrast to other terminal electron acceptors (e.g. nitrate or sulfate), the concentration of Fe3+(aq), is limited by the low solubility of Fe(III) oxyhydroxides unde

  14. Dissimilatory Reduction of Fe(III) and Other Electron Acceptors by a Thermus Isolate

    Energy Technology Data Exchange (ETDEWEB)

    Kieft, T. L. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States); Fredrickson, J. K. [Pacific Northwest National Lab., Richland, WA (United States); Onstott, T. C. [Princeton Univ., NJ (United States). Dept. of Geological and Geophysical Sciences; Gorby, Y. A. [Pacific Northwest National Lab., Richland, WA (United States); Kostandarithes, H. M. [Pacific Northwest National Lab., Richland, WA (United States); Bailey, T. J. [Pacific Northwest National Lab., Richland, WA (United States); Kennedy, D. W. [Pacific Northwest National Lab., Richland, WA (United States); Li, S. W. [Pacific Northwest National Lab., Richland, WA (United States); Plymale, A. E. [Pacific Northwest National Lab., Richland, WA (United States); Spadoni, C. M. [Pacific Northwest National Lab., Richland, WA (United States); Gray, M. S. [Pacific Northwest National Lab., Richland, WA (United States)

    1995-10-25

    A thermophilic bacterium that could use O{sub 2}, NO{sub 3}{sup -}, Fe(III), or S{sup o} as terminal electron acceptors for growth was isolated from groundwater sampled at 3.2 km depth in a South African gold mine. This organism, designated SA-01, clustered most closely with members of the genus Thermus, as determined by 16S rDNA gene sequence analysis. The 16S rDNA sequence of SA-01 was >98% similar to that of Thermus strain NMX2 A.1, which was previously isolated by other investigators from a thermal spring in New Mexico. Strain NMX2 A.1 was also able to reduce Fe(III) and other electron acceptors, whereas Thermus aquaticus (ATCC 25104) and Thermus filiformis (ATCC 43280) did not reduce NO{sub 3}{sup -} or Fe(III). Neither SA-01 nor NMX2 A.1 grew fermentatively, i.e., addition of an external electron acceptor was required for anaerobic growth. Thermus SA-01 reduced soluble Fe(III) complexed with citrate or nitrilotriacetic acid (NTA); however, it could only reduce relatively small quantities (0.5 mM) of hydrous ferric oxide (HFO) except when the humic acid analog 2,6-anthraquinone disulfonate (AQDS) was added as an electron shuttle, in which case 10 mM Fe(III) was reduced. Fe(III)-NTA was reduced quantitatively to Fe(II), was coupled to the oxidation of lactate, and could support growth through three consecutive transfers. Suspensions of Thermus SA-01 cells also reduced Mn(IV), Co(III)-EDTA, Cr(VI), and AQDS. Mn(IV)-oxide was reduced in the presence of either lactate or H{sub 2}. Both strains were also able to mineralize NTA to CO{sub 2} and to couple its oxidation to Fe(III) reduction and growth. The optimum temperature for growth and Fe(III) reduction by Thermus SA-01 and NMX2 A.1 is approximately 65 C; optimum pH is 6.5 to 7.0. This is the first report of a Thermus sp. being able to couple the oxidation of organic compounds to the reduction of Fe, Mn or S.

  15. Removal characteristics of Cd(II) ions from aqueous solution on ordered mesoporous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Linhang; Zhao, Haibo; Yan, Lu; Wang, Guowei; Mao, Yulin; Wang, Xin; Liu, Kai; Liu, Xiufang; Zhao, Qian; Jiang, Tingshun [Jiangsu University, Jiangsu (China)

    2015-10-15

    Ordered mesoporous carbon (CMK-3) was synthesized using SBA-15 mesoporous molecular sieve as a template and sucrose as carbon source. The materials were characterized by XRD, TEM and N2 physical adsorption technique. The resulting CMK-3 was used as adsorbent to remove Cd(II) ions from aqueous solution. The effect of pH, contact time and temperature on adsorption process was investigated in batch experiments. The results showed that the removal percentage could reach ca. 90% at the conditions of initial Cd(II) ions concentration of 20 mg/L, dose of 20mg, pH 6.5, contact time of 3h and 293K. Langmuir and Freundlich models were employed to describe the adsorption equilibrium. The kinetics data were described by the pseudo-first-order and pseudo-second-order models, respectively. The adsorption isotherm was well fitted to the Langmuir model, and the adsorption process was well described by the pseudo-second-order kinetic model.

  16. Rapid photooxidation of Sb(III) in the presence of different Fe(III) species

    Science.gov (United States)

    Kong, Linghao; He, Mengchang; Hu, Xingyun

    2016-05-01

    The toxicity and mobility of antimony (Sb) are strongly influenced by the redox processes associated with Sb. Dissolved iron (Fe) is widely distributed in the environment as different species and plays a significant role in Sb speciation. However, the mechanisms of Sb(III) oxidation in the presence of Fe have remained unclear because of the complexity of Fe and Sb speciation. In this study, the mechanisms of Sb(III) photooxidation in the presence of different Fe species were investigated systematically. The photooxidation of Sb(III) occurred over a wide pH range, from 1 to 10. Oxygen was not a predominant or crucial factor in the Sb(III) oxidation process. The mechanism of Sb(III) photooxidation varied depending on the Fe(III) species. In acidic solution (pH 1-3), dichloro radicals (radCl2-) and hydroxyl radicals (radOH) generated by the photocatalysis of FeCl2+ and FeOH2+ were the main oxidants for Sb(III) oxidation. Fe(III) gradually transformed into the colloid ferric hydroxide (CFH) and ferrihydrite in circumneutral and alkaline solutions (pH 4-10). Photooxidation of Sb(III) occurred through electron transfer from Sb(III) to Fe(III) along with the reduction of Fe(III) to Fe(II) through a ligand-to-metal charge-transfer (LMCT) process. The photocatalysis of different Fe(III) species may play an important role in the geochemical cycle of Sb(III) in surface soil and aquatic environments.

  17. Investigation on the efficiency and mechanism of Cd(II) and Pb(II) removal from aqueous solutions using MgO nanoparticles.

    Science.gov (United States)

    Xiong, Chunmei; Wang, Wei; Tan, Fatang; Luo, Fan; Chen, Jianguo; Qiao, Xueliao

    2015-12-15

    In this study, the removal of Cd(II) and Pb(II) from aqueous solutions using MgO nanoparticles prepared by a simple sol-gel method was investigated. The efficiency of Cd(II) and Pb(II) removal was examined through batch adsorption experiments. For the single adsorption of Cd(II) and Pb(II), The adsorption kinetics and isotherm data obeyed well Pseudo-second-order and Langmuir models, indicating the monolayer chemisorption of heavy metal ions. The maximum adsorption capacities calculated by Langmuir equation were 2294 mg/g for Cd(II) and 2614 mg/g for Pb(II), respectively. The adsorption process was controlled simultaneously by external mass transfer and intraparticle diffusion. In the binary system, a competitive adsorption was observed, showing preference of adsorption followed Pb(II) >Cd(II). Significantly, the elution experiments confirmed that neither Cd(II) nor Pb(II) could be greatly desorbed after water washing even for five times. XRD and XPS measurements revealed the mechanism of Cd(II) and Pb(II) removal by MgO nanoparticles was mainly involved in precipitation and adsorption on the surface of MgO, resulting from the interaction between active sites of MgO and heavy metal ions. Easy preparation, remarkable removal efficiency and firmly adsorptive ability make the MgO nanoparticles to be an efficient material in the treatment of heavy metal-contaminated water.

  18. Cd(II) complexes with different nuclearity and dimensionality based on 3-hydrazino-4-amino-1,2,4-triazole

    Science.gov (United States)

    Xu, Cai-Xia; Zhang, Jian-Guo; Yin, Xin; Jin, Xin; Li, Tong; Zhang, Tong-Lai; Zhou, Zun-Ning

    2015-03-01

    A series of zero- to two-dimensional Cd(II) coordination compounds have been synthesized by the reaction of Cd(II) salts and 3-hydrazino-4-amino-1,2,4-triazole di-hydrochloride (HATr·2HCl). [CdCl2(HATr)2] (1) and [Cd2Cl4(HATr)2(H2O)2] (2) have discrete mononuclear and binuclear structures, respectively. [Cd(HATr)2(ClO4)2]n (3) presents polymeric 1-D chain and [Cd2(NO3)2Cl2(HATr)2]n (4) shows 2-D frameworks. All Cd(II) ions exhibit distorted octahedral configurations in 1-3, whilst both hexa and heptacoordinated Cd(II) are formed in 4. The HATr ligands adopt chelating coordinated mode in 1, while tri-dentate bridging-chelating mode in 2-4. The chloride ion is a mono-coordinated ligand in 1 and 2, but it bridges two adjacent metal ions in 4. Furthermore, thermal behaviors have been investigated and the results reveal that all complexes have good thermal stability. The impact sensitivity test indicates that complex 3 is sensitive to impact stimuli.

  19. Crosslinked chitosan/polyvinyl alcohol blend beads for removal and recovery of Cd(II) from wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Mahendra; Tripathi, Bijay P. [Electro-Membrane Processes Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364002, Gujarat (India); Shahi, Vinod K., E-mail: vkshahi@csmcri.org [Electro-Membrane Processes Division, Central Salt and Marine Chemicals Research Institute, Council of Scientific and Industrial Research (CSIR), G.B. Marg, Bhavnagar 364002, Gujarat (India)

    2009-12-30

    Crosslinked chitosan/poly(vinyl alcohol) (PVA) beads were prepared by suspension of chitosan-PVA aqueous solution in a mixture of toluene and chlorobenzene. Some quantity of the water was distilled out as an azeotrope along with toluene-chlorobenzene and the droplets were chemically crosslinked by adding glutaraldehyde. The prepared crosslinked beads were characterized by FTIR, X-ray diffraction (XRD), and scanning electron microscopy (SEM). The developed beads were used as an adsorbent for the adsorption of Cd(II) from wastewater. Effect of time, temperature, pH, adsorbent dose and adsorbate concentration on the adsorption of Cd(II) were investigated in batch process and pseudo-first and pseudo-second-order kinetic models were also evaluated. The equilibrium adsorption obeyed Langmuir and Freundlich isotherms as well as the thermodynamic parameters such as {Delta}G{sup o}, {Delta}H{sup o} and {Delta}S{sup o} were calculated. From thermodynamic data, it was found that the adsorption process was endothermic and spontaneous. The maximum adsorption of Cd(II) ions was found to be 73.75% at pH 6 and indicated that developed material could be effectively utilized for the removal of Cd(II) ions from wastewater.

  20. Removal of Pb(II) and Cd(II) ions from aqueous solution by thiosemicarbazide modified chitosan.

    Science.gov (United States)

    Li, Manlin; Zhang, Zengqiang; Li, Ronghua; Wang, Jim J; Ali, Amjad

    2016-05-01

    The removal of Pb(II) and Cd(II) ions from aqueous solution by thiosemicarbazide modified chitosan (TCS) was studied in this article. The synthesized TCS was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), element analysis, N2 adsorption-desorption, scanning electron microscopy (SEM) and X-ray photoelectron spectrophotometer (XPS). Moreover, the influence of solution pH, contact time, initial heavy metal concentration, and solution temperature on the adsorption process was examined, and the adsorbent reusability and adsorption mechanisms were also studied. The results showed that TCS adsorbed greater amount of Pb(II) and Cd(II) ions than the raw chitosan. The adsorption amounts of Pb(II) and Cd(II) ions were affected by increasing solution pH and temperature. The maximum adsorption capacities of the TCS for Pb(II) and Cd(II) ions were found to be 325.2 and 257.2 mg/g, respectively. The endothermic adsorption fitted the pseudo-second-order kinetics equation and the adsorption isotherms could be well described by Langmuir model. The metal ions adsorption mechanism was concluded to be mainly dominated by complexation reaction process. The desorption study indicated that the target adsorbent was easy to be regenerated.

  1. Experimental analysis and mathematical prediction of Cd(II) removal by biosorption using support vector machines and genetic algorithms.

    Science.gov (United States)

    Hlihor, Raluca Maria; Diaconu, Mariana; Leon, Florin; Curteanu, Silvia; Tavares, Teresa; Gavrilescu, Maria

    2015-05-25

    We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R(2)>0.99. The value of the mean free energy of adsorption, E, is less than 16 kJ/mol at 25 °C, suggesting that, at low temperature, the dominant process involved in Cd(II) biosorption by dead T. viride is the chemical ion-exchange. With the temperature increasing to 40-50 °C, E values are above 16 kJ/mol, showing that the particle diffusion mechanism could play an important role in Cd(II) biosorption. The studies on T. viride growth in Cd(II) solutions and its bioaccumulation performance showed that the living biomass was able to bioaccumulate 100% Cd(II) from a 50 mg/L solution at pH 6.0. The influence of pH, biomass dosage, metal concentration, contact time and temperature on the bioremoval efficiency was evaluated to further assess the biosorption capability of the dead biosorbent. These complex influences were correlated by means of a modeling procedure consisting in data driven approach in which the principles of artificial intelligence were applied with the help of support vector machines (SVM), combined with genetic algorithms (GA). According to our data, the optimal working conditions for the removal of 98.91% Cd(II) by T. viride were found for an aqueous solution containing 26.11 mg/L Cd(II) as follows: pH 6.0, contact time of 3833 min, 8 g/L biosorbent, temperature 46.5 °C. The complete characterization of bioremoval parameters indicates that T. viride is an excellent material to treat wastewater containing low concentrations of metal.

  2. Adsorptive removal of Cd(II) and Pb(II) ions from aqueous solutions by using Turkish illitic clay.

    Science.gov (United States)

    Ozdes, Duygu; Duran, Celal; Senturk, Hasan Basri

    2011-12-01

    The ability of Turkish illitic clay (TIC) in removal of Cd(II) and Pb(II) ions from aqueous solutions has been examined in a batch adsorption process with respect to several experimental conditions including initial solution pH, contact time, initial metal ions concentration, temperature, ionic strength, and TIC concentration, etc. The characterization of TIC was performed by using FTIR, XRD and XRF techniques. The maximum uptake of Cd(II) (11.25 mg g(-1)) and Pb(II) (238.98 mg g(-1)) was observed when used 1.0 g L(-1) of TIC suspension, 50 mg L(-1) of initial Cd(II) and 250 mg L(-1) of initial Pb(II) concentration at initial pH 4.0 and contact time of 240 min at room temperature. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin Radushkevich (D-R) isotherm models. The monolayer adsorption capacity of TIC was found to be 13.09 mg g(-1) and 53.76 mg g(-1) for Cd(II) and Pb(II) ions, respectively. The kinetics of the adsorption was tested using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. The results showed that the adsorption of Cd(II) and Pb(II) ions onto TIC proceeds according to the pseudo-second-order model. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the present adsorption process was feasible, spontaneous and endothermic in the temperature range of 5-40 °C.

  3. PROSPEKTIF LEMPUNG ALAM CENGAR SEBAGAI ADSORBEN POLUTAN ANORGANIK DI DALAM AIR: KAJIAN KINETIKA ADSORPSI KATION Co(II

    Directory of Open Access Journals (Sweden)

    Muhdarina Muhdarina

    2012-02-01

    Full Text Available Kemampuan lempung alam Cengar untuk melepaskan kation Co(II dari air limbah model telah diuji dengan proses adsorpsi. Lempung alam Cengar diimpregnasi dengan larutan garam ammonium 1 molar untuk meningkatkan kemampuan adsorpsinya. Kapasitas adsorpsi kation Co(II oleh lempung Cengar yang diimpregnasi meningkat di bawah pengaruh waktu kontak dan menurun dengan temperatur. Beberapa model kinetika yaitu order-pertama pseudo, order-kedua pseudo, model Elovich dan difusi intra-partikel telah digunakan untuk mengevaluasi kinetika dan mekanisme interaksi Co(II pada lempung Cengar. Mekanisme adsorpsi Co(II-lempung Cengar mengikuti kinetika order-kedua pseudo pada waktu perolehan adsorbat maksimum 120 menit. Dengan model Elovich didapatkan adsorben lempung Cengar memiliki permukaan yang heterogen. Energi aktivasi proses adsorpsi juga dievaluasi di bawah pengaruh temperatur dan didapatkan energi aktivasi yang negatif.

  4. Sequence analysis of a few species of termites (Order: Isoptera) on the basis of partial characterization of COII gene.

    Science.gov (United States)

    Sobti, Ranbir Chander; Kumari, Mamtesh; Sharma, Vijay Lakshmi; Sodhi, Monika; Mukesh, Manishi; Shouche, Yogesh

    2009-11-01

    The present study was aimed to get the nucleotide sequences of a part of COII mitochondrial gene amplified from individuals of five species of Termites (Isoptera: Termitidae: Macrotermitinae). Four of them belonged to the genus Odontotermes (O. obesus, O. horni, O. bhagwatii and Odontotermes sp.) and one to Microtermes (M. obesi). Partial COII gene fragments were amplified by using specific primers. The sequences so obtained were characterized to calculate the frequencies of each nucleotide bases and a high A + T content was observed. The interspecific pairwise sequence divergence in Odontotermes species ranged from 6.5% to 17.1% across COII fragment. M. obesi sequence diversity ranged from 2.5 with Odontotermes sp. to 19.0% with O. bhagwatii. Phylogenetic trees drawn on the basis of distance neighbour-joining method revealed three main clades clustering all the individuals according to their genera and families.

  5. Unusual composition dependence of magnetic relaxation for Co(II)(1-x)Ni(II)(x) chain-based metal-organic frameworks.

    Science.gov (United States)

    Wang, Yan-Qin; Cheng, Ai-Ling; Liu, Pei-Pei; Gao, En-Qing

    2013-08-11

    A series of isomorphous 3D Co(II)(1-x)Ni(II)(x) MOFs based on ferromagnetic chains show SCM-type slow relaxation and the Co-rich system can exhibit a higher blocking temperature than both Co(II) and Ni(II) parent materials.

  6. Extraction of Fe(III) and U(VI) with 1-phenyl-3-methyl-4-acyl-pyrazolones-5 from aqueous solutions of different acids and complexing agents. Separation of Fe(III) from U(VI)

    Energy Technology Data Exchange (ETDEWEB)

    Okafor, E.C. (Nigeria Univ., Nsukka (Nigeria). Dept. of Pure and Industrial Chemistry); Uzoukwu, B.A. (Port Harcourt Univ. (Nigeria). Dept. of Pure and Industrial Chemistry)

    1990-01-01

    Solvent extraction behaviour of Fe(III) and U(VI) in aqueous media containing various mineral acids or complexing agents, using 4-butyryl, 4-palmitoyl and 4-trichloroacetyl derivatives of 1-phenyl-3-methyl-pyrazolone-5 in xylene as extraction reagents have been studied. The possible extraction mechanism has been investigated. Solid complexes of Fe(III) and U(VI) with the chelating agents have been isolated and analysed. Separation factors of Fe(III) and U(VI) using these chelating agents are reported and methods suggested for separation of Fe(III) from U(VI) in an aqueous medium containing 0.1 M HCl or 5x10{sup -4} M EDTA. (orig.).

  7. An unprecedented Co(II) cuboctahedron as the secondary building unit in a Co-based metal-organic framework.

    Science.gov (United States)

    Holmberg, Rebecca J; Kay, Marika; Korobkov, Ilia; Kadantsev, Eugene; Boyd, Peter G; Aharen, Tomoko; Desgreniers, Serge; Woo, Tom K; Murugesu, Muralee

    2014-05-25

    A cubic metal-organic framework with an unprecedented octanuclear secondary building unit (SBU) was isolated. The obtained SBU is composed of 8 Co(II) ions at each vertex, 6 μ4-OH groups at each face, and 12 cpt(-) ligands framing the metal core. The cuboctahedra arrange in a ubt framework topology, eliciting a highly symmetrical MOF structure. Magnetic measurements as well as DFT calculations on this crystalline MOF reveal intramolecular antiferromagnetic coupling between Co(II) ions in the octanuclear SBU.

  8. Nontronite (NAu-1) Structure Associated with Microbial Fe(III) Reduction in Various Redox Conditions

    Science.gov (United States)

    Koo, T.; Kim, S.; Kim, J.

    2011-12-01

    Shewanella oneidensis MR-1 respires the structural Fe(III) of smectite and promotes illite formation in O2-free environment (Kostka et al., 1996, Kim et al., 2004). Since S. oneidensis is a facultative iron reducing bacterium, it is crucial to understand the structural changes induced by bio-reduction of structural Fe(III) in various redox conditions. Furthermore, the changes in cation exchange capacity (CEC) of bio-reduced nontronite upon the modification of mineral structure has not been extensively studied in terms of Fe-cycling. In this present study, we reported the evolution of nontronite structure at various time points in various redox conditions and corresponding CEC upon reduction and re-oxidation. S. oneidensis MR-1 was incubated in M1 medium with Na-lactate as the electron donor and Fe in nontronite (NAu-1) as the sole electron acceptor at pH 7 in anaerobic chamber for 3 hrs, 12 hrs, 1 day, 2 days, 4 days, 7 days, 14 days, and 21 days. O2 gas bubbling was then applied to the sample at each time point for 24 hours for re-oxidation. The triplet samples at each time point for both reduction and re-oxidation experiments were prepared. The extent of Fe(III) reduction measured by 1,10-phenanthroline method (Stucki and Anderson, 1981) indicated that the structural Fe(III) was reduced up to 8.8% of total Fe(III) within 21 days. XRD data with various treatments such as air dried, glycolated and lithium-saturated showed that K-nontronite may be formed because no discrete 10-Å illite peak was observed in Li-saturated sample upon glycolation. The CEC increased from 747 meg/kg to 1145 meg/kg during Fe(III) reduction and decreased to 954 meg/kg upon re-oxidation, supporting the possible formation of K-nontronite. The direct observation by electron microscopy verified the structural changes in nontonite in various redox conditions. The long-term experiment for 6 months, is in progress in anaerobic chamber, and results will be discussed. Kim, J. W., Dong, H., Seabaugh

  9. Photochemical degradation of environmentally persistent perfluorooctanoic acid (PFOA) in the presence of Fe(III)

    Institute of Scientific and Technical Information of China (English)

    Yuan Wang; Peng Yi Zhang; Gang Pan; Hao Chen

    2008-01-01

    Environmentally persistent and bioaccumulative perfluorooctanic acid (PFOA) was difficult to be decomposed under the irradiation of 254 nm UV light. However, in the presence of 80μmol /L Fe(III), 80% of PFOA with initial concentration of 48μmol/L (20 mg/L) was effectively degraded and 47.8% of fluorine atoms in PFOA molecule were transformed into inorganic fluoride ion after 4 h reaction. Shorter chain perfluorocarboxylic acids bearing C3-C7 and fluoride ion were detected and identified by LC/MS and IC as the degradation products in the aqueous solution. It was proposed that complexes of PFOA with Fe(III) initiated degradation of PFOA irradiated with 254 nm UV light.

  10. Co(II)4, Co(II)7, and a Series of Co(II)2Ln(III) (Ln(III) = Nd(III), Sm(III), Gd(III), Tb(III), Dy(III)) Coordination Clusters: Search for Single Molecule Magnets.

    Science.gov (United States)

    Modak, Ritwik; Sikdar, Yeasin; Thuijs, Annaliese E; Christou, George; Goswami, Sanchita

    2016-10-03

    We report herein the syntheses and investigation of the magnetic properties of a Co(II)4 compound, a series of trinuclear Co(II)2Ln(III) (Ln(III) = Nd(III), Sm(III), Gd(III), Tb(III), Dy(III)) complexes, and a Co(II)7 complex. The homometallic Co(II)4 core was obtained from the reaction of Ln(NO3)3·xH2O/Co(NO3)2·6H2O/H2vab/Et3N in a 0.5:0.5:1:2 ratio in methanol. Variation in synthetic conditions was necessary to get the desired Co(II)-Ln(III) complexes. The Co(II)-Ln(III) assembly was synthesized from Ln(NO3)3·xH2O/Co(OAc)2·4H2O/H2vab/NaOMe in a 0.4:0.5:1:1 ratio in methanol. The isostructural Co(II)2Ln(III) complexes have a core structure with the general formula [Co2Ln(Hvab)4(NO3)](NO3)2·MeOH·H2O, (where H2vab = 2-[(2-hydroxymethyl-phenylimino)-methyl]-6-methoxy-phenol) with simultaneous crystallization of Co(II)7 complex in each reaction. The magnetic investigation of these complexes reveals that both homometallic complexes and four Co(II)-Ln(III) complexes (except Co(II)-Nd(III)) display behavior characteristic of single molecule magnets.

  11. Co(II Complex of Mefloquine Hydrochloride: Synthesis, Antimicrobial Potential, Antimalaria and Toxicological Activities

    Directory of Open Access Journals (Sweden)

    Adediji J. Femi

    2012-01-01

    Full Text Available Transition metal complex of Co(II with Mefloquine hydrochloride (antimalaria drug was synthesized using template method. Chemical analysis including conductivity measurements and spectroscopic studies were used to propose the geometry and mode of binding of the ligand to metal ion. From analytical data, the stoichiometry of the complex has been found to be 1:1. Infrared spectral data also suggest that the ligand (mefloquine hydrochloride behaves as a tridentate ligand with N:N:O donor sequence towards the metal ion. The complex generally showed octahedral coordinate geometry. Conductivity measurement of 10-2 mol dm-3 methanol solution of the complex indicated non-electrolytic nature of metal complex. It also revealed that the ligand anions were covalently bonded to the complex. In-vivo evaluation of antimicrobial studies of the metal complex showed greater activities when compared to the free mefloquine.The complex was screened against malarial parasites (Plasmodium yoelii nigeriensis: It was evident from the results obtained that Co(II mefloquine has highest clearance of about 80% parasitaemia reduction compared to the free mefloquine. The ligand and metal complex were screened for their toxicological activities at the dose of 0.60 mg/Kg body weight twice daily for seven days on the alkaline phosphatase (ALP, alanine aminotranferase (ALT, and aspartate aminotransferase (AST activities of rat serum, liver and kidney. Overall, it was revealed that both mefloquine and its metal complex do not showed toxicity particularly on the liver and kidney.

  12. Shewanella oneidensis MR-1-Induced Fe(III) Reduction Facilitates Roxarsone Transformation

    OpenAIRE

    2016-01-01

    Although microbial activity and associated iron (oxy)hydroxides are known in general to affect the environmental dynamics of 4-hydroxy-3-nitrobenzenearsonic acid (roxarsone), the mechanistic understanding of the underlying biophysico-chemical processes remains unclear due to limited experimental information. We studied how Shewanella oneidensis MR-1 –a widely distributed metal-reducing bacterium, in the presence of dissolved Fe(III), affects roxarsone transformations and biogeochemical cyclin...

  13. Microbial Fe(III) oxide reduction potential in Chocolate Pots hot spring, Yellowstone National Park.

    Science.gov (United States)

    Fortney, N W; He, S; Converse, B J; Beard, B L; Johnson, C M; Boyd, E S; Roden, E E

    2016-05-01

    Chocolate Pots hot springs (CP) is a unique, circumneutral pH, iron-rich, geothermal feature in Yellowstone National Park. Prior research at CP has focused on photosynthetically driven Fe(II) oxidation as a model for mineralization of microbial mats and deposition of Archean banded iron formations. However, geochemical and stable Fe isotopic data have suggested that dissimilatory microbial iron reduction (DIR) may be active within CP deposits. In this study, the potential for microbial reduction of native CP Fe(III) oxides was investigated, using a combination of cultivation dependent and independent approaches, to assess the potential involvement of DIR in Fe redox cycling and associated stable Fe isotope fractionation in the CP hot springs. Endogenous microbial communities were able to reduce native CP Fe(III) oxides, as documented by most probable number enumerations and enrichment culture studies. Enrichment cultures demonstrated sustained DIR driven by oxidation of acetate, lactate, and H2 . Inhibitor studies and molecular analyses indicate that sulfate reduction did not contribute to observed rates of DIR in the enrichment cultures through abiotic reaction pathways. Enrichment cultures produced isotopically light Fe(II) during DIR relative to the bulk solid-phase Fe(III) oxides. Pyrosequencing of 16S rRNA genes from enrichment cultures showed dominant sequences closely affiliated with Geobacter metallireducens, a mesophilic Fe(III) oxide reducer. Shotgun metagenomic analysis of enrichment cultures confirmed the presence of a dominant G. metallireducens-like population and other less dominant populations from the phylum Ignavibacteriae, which appear to be capable of DIR. Gene (protein) searches revealed the presence of heat-shock proteins that may be involved in increased thermotolerance in the organisms present in the enrichments as well as porin-cytochrome complexes previously shown to be involved in extracellular electron transport. This analysis offers

  14. Applying the Fe(III) binding property of a chemical transferrin mimetic to Ti(IV) anticancer drug design.

    Science.gov (United States)

    Parks, Timothy B; Cruz, Yahaira M; Tinoco, Arthur D

    2014-02-03

    As an endogenous serum protein binder of Ti(IV), transferrin (Tf) serves as an excellent vehicle to stabilize the hydrolysis prone metal ion and successfully transport it into cells. This transporting role is thought to be central to Ti(IV)'s anticancer function, but efforts to synthesize Ti(IV) compounds targeting transferrin have not produced a drug. Nonetheless, the Ti(IV) transferrin complex (Ti2Tf) greatly informs on a new Ti(IV)-based anticancer drug design strategy. Ti2Tf interferes with cellular uptake of Fe(III), which is particularly detrimental to cancer cells because of their higher requirement for iron. Ti(IV) compounds of chemical transferrin mimetic (cTfm) ligands were designed to facilitate Ti(IV) activity by attenuating Fe(III) intracellular levels. In having a higher affinity for Fe(III) than Ti(IV), these ligands feature the appropriate balance between stability and lability to effectively transport Ti(IV) into cancer cells, release Ti(IV) via displacement by Fe(III), and deplete the intracellular Fe(III) levels. The cTfm ligand N,N'-di(o-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED) was selected to explore the feasibility of the design strategy. Kinetic studies on the Fe(III) displacement process revealed that Ti(IV) can be transported and released into cells by HBED on a physiologically relevant time scale. Cell viability studies using A549 cancerous and MRC5 normal human lung cells and testing the cytotoxicity of HBED and its Ti(IV), Fe(III), and Ga(III) compounds demonstrate the importance of Fe(III) depletion in the proposed drug design strategy and the specificity of the strategy for Ti(IV) activity. The readily derivatized cTfm ligands demonstrate great promise for improved Ti(IV) anticancer drugs.

  15. Shewanella oneidensis MR-1-Induced Fe(III) Reduction Facilitates Roxarsone Transformation.

    Science.gov (United States)

    Chen, Guowei; Ke, Zhengchen; Liang, Tengfang; Liu, Li; Wang, Gang

    2016-01-01

    Although microbial activity and associated iron (oxy)hydroxides are known in general to affect the environmental dynamics of 4-hydroxy-3-nitrobenzenearsonic acid (roxarsone), the mechanistic understanding of the underlying biophysico-chemical processes remains unclear due to limited experimental information. We studied how Shewanella oneidensis MR-1 -a widely distributed metal-reducing bacterium, in the presence of dissolved Fe(III), affects roxarsone transformations and biogeochemical cycling in a model aqueous system. The results showed that the MR-1 strain was able to anaerobically use roxarsone as a terminal electron acceptor and to convert it to a single product, 3-amino-4-hydroxybenzene arsonic acid (AHBAA). The presence of Fe(III) stimulated roxarsone transformation via MR-1-induced Fe(III) reduction, whereby the resulting Fe(II) acted as an efficient reductant for roxarsone transformation. In addition, the subsequent secondary Fe(III)/Fe(II) mineralization created conditions for adsorption of organoarsenic compounds to the yielded precipitates and thereby led to arsenic immobilization. The study provided direct evidence of Shewanella oneidensis MR-1-induced direct and Fe(II)-associated roxarsone transformation. Quantitative estimations revealed a candidate mechanism for the early-stage environmental dynamics of roxarsone in nature, which is essential for understanding the environmental dynamics of roxarsone and successful risk assessment.

  16. Evidence for the aquatic binding of arsenate by natural organic matter-suspended Fe(III)

    Science.gov (United States)

    Ritter, K.; Aiken, G.R.; Ranville, J.F.; Bauer, M. E.; Macalady, D.L.

    2006-01-01

    Dialysis experiments with arsenate and three different NOM samples amended with Fe(III) showed evidence confirming the formation of aquatic arsenate-Fe(III)-NOM associations. A linear relationship was observed between the amount of complexed arsenate and the Fe(III) content of the NOM. The dialysis results were consistent with complex formation through ferric iron cations acting as bridges between the negatively charged arsenate and NOM functional groups and/or a more colloidal association, in which the arsenate is bound by suspended Fe(III)-NOM colloids. Sequential filtration experiments confirmed that a significant proportion of the iron present at all Fe/C ratios used in the dialysis experiments was colloidal in nature. These colloids may include larger NOM species that are coagulated by the presence of chelated Fe(III) and/or NOM-stabilized ferric (oxy)hydroxide colloids, and thus, the solution-phase arsenate-Fe(III)-NOM associations are at least partially colloidal in nature. ?? 2006 American Chemical Society.

  17. Shewanella oneidensis MR-1-Induced Fe(III) Reduction Facilitates Roxarsone Transformation

    Science.gov (United States)

    Chen, Guowei; Ke, Zhengchen; Liang, Tengfang; Liu, Li; Wang, Gang

    2016-01-01

    Although microbial activity and associated iron (oxy)hydroxides are known in general to affect the environmental dynamics of 4-hydroxy-3-nitrobenzenearsonic acid (roxarsone), the mechanistic understanding of the underlying biophysico-chemical processes remains unclear due to limited experimental information. We studied how Shewanella oneidensis MR-1 –a widely distributed metal-reducing bacterium, in the presence of dissolved Fe(III), affects roxarsone transformations and biogeochemical cycling in a model aqueous system. The results showed that the MR-1 strain was able to anaerobically use roxarsone as a terminal electron acceptor and to convert it to a single product, 3-amino-4-hydroxybenzene arsonic acid (AHBAA). The presence of Fe(III) stimulated roxarsone transformation via MR-1-induced Fe(III) reduction, whereby the resulting Fe(II) acted as an efficient reductant for roxarsone transformation. In addition, the subsequent secondary Fe(III)/Fe(II) mineralization created conditions for adsorption of organoarsenic compounds to the yielded precipitates and thereby led to arsenic immobilization. The study provided direct evidence of Shewanella oneidensis MR-1-induced direct and Fe(II)-associated roxarsone transformation. Quantitative estimations revealed a candidate mechanism for the early-stage environmental dynamics of roxarsone in nature, which is essential for understanding the environmental dynamics of roxarsone and successful risk assessment. PMID:27100323

  18. Studies on Synthetic and Natural Melanin and Its Affinity for Fe(III Ion

    Directory of Open Access Journals (Sweden)

    T. G. Costa

    2012-01-01

    Full Text Available In this work, we measured the metal-binding sites of natural and synthetic dihydroxyindole (DHI melanins and their respective interactions with Fe(III ions. Besides the two acid groups detected for the DHI system: catechol (Cat and quinone-imine (QI, acetate groups were detected in the natural oligomer by potentiometric titrations. At acidic pH values, Fe(III complexation with synthetic melanin was detected in an Fe(OH(CatH2Cat interaction. With an increase of pH, three new interactions occurred: dihydroxide diprotonated catechol, Fe(OH2(CatH2Cat−, dihydroxide monoprotonated catechol, [Fe(OH2(CatHCat]2−, and an interaction resulting from the association of one quinone-imine and a catechol group, [Fe(OH2(Qi−(CatHCat]3−. In the natural melanin system, we detected the same interactions involving catechol and quinone-imine groups but also the metal interacts with acetate group at pH values lower than 4.0. Furthermore, interactions in the synthetic system were also characterized by infrared spectroscopy by using the characteristic vibrations of catechol and quinone-imine groups. Finally, scanning electronic microscopy (SEM and energy-dispersive X-ray (EDS analysis were used to examine the differences in morphology of these two systems in the absence and presence of Fe(III ions. The mole ratio of metal and donor atoms was obtained by the EDS analysis.

  19. Fate of Cd during microbial Fe(III) mineral reduction by a novel and Cd-tolerant Geobacter species.

    Science.gov (United States)

    Muehe, E Marie; Obst, Martin; Hitchcock, Adam; Tyliszczak, Tolek; Behrens, Sebastian; Schröder, Christian; Byrne, James M; Michel, F Marc; Krämer, Ute; Kappler, Andreas

    2013-12-17

    Fe(III) (oxyhydr)oxides affect the mobility of contaminants in the environment by providing reactive surfaces for sorption. This includes the toxic metal cadmium (Cd), which prevails in agricultural soils and is taken up by crops. Fe(III)-reducing bacteria can mobilize such contaminants by Fe(III) mineral dissolution or immobilize them by sorption to or coprecipitation with secondary Fe minerals. To date, not much is known about the fate of Fe(III) mineral-associated Cd during microbial Fe(III) reduction. Here, we describe the isolation of a new Geobacter sp. strain Cd1 from a Cd-contaminated field site, where the strain accounts for 10(4) cells g(-1) dry soil. Strain Cd1 reduces the poorly crystalline Fe(III) oxyhydroxide ferrihydrite in the presence of at least up to 112 mg Cd L(-1). During initial microbial reduction of Cd-loaded ferrihydrite, sorbed Cd was mobilized. However, during continuous microbial Fe(III) reduction, Cd was immobilized by sorption to and/or coprecipitation within newly formed secondary minerals that contained Ca, Fe, and carbonate, implying the formation of an otavite-siderite-calcite (CdCO3-FeCO3-CaCO3) mixed mineral phase. Our data shows that microbially mediated turnover of Fe minerals affects the mobility of Cd in soils, potentially altering the dynamics of Cd uptake into food or phyto-remediating plants.

  20. Online spectrophotometric determination of Fe(II) and Fe(III) by flow injection combined with low pressure ion chromatography

    Science.gov (United States)

    Chen, Shujuan; Li, Nan; Zhang, Xinshen; Yang, Dongjing; Jiang, Heimei

    2015-03-01

    A simple and new low pressure ion chromatography combined with flow injection spectrophotometric procedure for determining Fe(II) and Fe(III) was established. It is based on the selective adsorption of low pressure ion chromatography column to Fe(II) and Fe(III), the online reduction reaction of Fe(III) and the reaction of Fe(II) in sodium acetate with phenanthroline, resulting in an intense orange complex with a suitable absorption at 515 nm. Various chemical (such as the concentration of colour reagent, eluant and reductive agent) and instrumental parameters (reaction coil length, reductive coil length and wavelength) were studied and were optimized. Under the optimum conditions calibration graph of Fe(II)/Fe(III) was linear in the Fe(II)/Fe(III) range of 0.040-1.0 mg/L. The detection limit of Fe(III) and Fe(II) was respectively 3.09 and 1.55 μg/L, the relative standard deviation (n = 10) of Fe(II) and Fe(III) 1.89% and 1.90% for 0.5 mg/L of Fe(II) and Fe(III) respectively. About 2.5 samples in 1 h can be analyzed. The interfering effects of various chemical species were studied. The method was successfully applied in the determination of water samples.

  1. Effect of oxidation rate and Fe(II) state on microbial nitrate-dependent Fe(III) mineral formation.

    Science.gov (United States)

    Senko, John M; Dewers, Thomas A; Krumholz, Lee R

    2005-11-01

    A nitrate-dependent Fe(II)-oxidizing bacterium was isolated and used to evaluate whether Fe(II) chemical form or oxidation rate had an effect on the mineralogy of biogenic Fe(III) (hydr)oxides resulting from nitrate-dependent Fe(II) oxidation. The isolate (designated FW33AN) had 99% 16S rRNA sequence similarity to Klebsiella oxytoca. FW33AN produced Fe(III) (hydr)oxides by oxidation of soluble Fe(II) [Fe(II)sol] or FeS under nitrate-reducing conditions. Based on X-ray diffraction (XRD) analysis, Fe(III) (hydr)oxide produced by oxidation of FeS was shown to be amorphous, while oxidation of Fe(II)sol yielded goethite. The rate of Fe(II) oxidation was then manipulated by incubating various cell concentrations of FW33AN with Fe(II)sol and nitrate. Characterization of products revealed that as Fe(II) oxidation rates slowed, a stronger goethite signal was observed by XRD and a larger proportion of Fe(III) was in the crystalline fraction. Since the mineralogy of Fe(III) (hydr)oxides may control the extent of subsequent Fe(III) reduction, the variables we identify here may have an effect on the biogeochemical cycling of Fe in anoxic ecosystems.

  2. The life cycle of iron Fe(III) oxide: impact of fungi and bacteria

    Science.gov (United States)

    Bonneville, Steeve

    2014-05-01

    Iron oxides are ubiquitous reactive constituents of soils, sediments and aquifers. They exhibit vast surface areas which bind a large array of trace metals, nutrients and organic molecules hence controlling their mobility/reactivity in the subsurface. In this context, understanding the "life cycle" of iron oxide in soils is paramount to many biogeochemical processes. Soils environments are notorious for their extreme heterogeneity and variability of chemical, physical conditions and biological agents at play. Here, we present studies investigating the role of two biological agents driving iron oxide dynamics in soils, root-associated fungi (mycorrhiza) and bacteria. Mycorrhiza filaments (hypha) grow preferentially around, and on the surface of nutrient-rich minerals, making mineral-fungi contact zones, hot-spots of chemical alteration in soils. However, because of the microscopic nature of hyphae (only ~ 5 µm wide for up to 1 mm long) and their tendency to strongly adhere to mineral surface, in situ observations of this interfacial micro-environment are scarce. In a microcosm, ectomycorrhiza (Paxillus involutus) was grown symbiotically with a pine tree (Pinus sylvestris) in the presence of freshly-cleaved biotite under humid, yet undersaturated, conditions typical of soils. Using spatially-resolved ion milling technique (FIB), transmission electron microscopy and spectroscopy (TEM/STEM-EDS), synchrotron based X-ray microscopy (STXM), we were able to quantify the speciation of Fe at the biotite-hypha interface. The results shows that substantial oxidation of biotite structural-Fe(II) into Fe(III) subdomains occurs at the contact zone between mycorrhiza and biotite. Once formed, iron(III) oxides can reductively dissolve under suboxic conditions via several abiotic and microbial pathways. In particular, they serve as terminal electron acceptors for the oxidation of organic matter by iron reducing bacteria. We aimed here to understand the role of Fe(III) mineral

  3. Mechanisms for Electron Transfer Through Pili to Fe(III) Oxide in Geobacter

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek R. [Univ. of Massachusetts, Amherst, MA (United States)

    2015-03-09

    The purpose of these studies was to aid the Department of Energy in its goal of understanding how microorganisms involved in the bioremediation of metals and radionuclides sustain their activity in the subsurface. This information is required in order to incorporate biological processes into decision making for environmental remediation and long-term stewardship of contaminated sites. The proposed research was designed to elucidate the mechanisms for electron transfer to Fe(III) oxides in Geobacter species because Geobacter species are abundant dissimilatory metal-reducing microorganisms in a diversity of sites in which uranium is undergoing natural attenuation via the reduction of soluble U(VI) to insoluble U(IV) or when this process is artificially stimulated with the addition of organic electron donors. This study investigated the novel, but highly controversial, concept that the final conduit for electron transfer to Fe(III) oxides are electrically conductive pili. The specific objectives were to: 1) further evaluate the conductivity along the pili of Geobacter sulfurreducens and related organisms; 2) determine the mechanisms for pili conductivity; and 3) investigate the role of pili in Fe(III) oxide reduction. The studies demonstrated that the pili of G. sulfurreducens are conductive along their length. Surprisingly, the pili possess a metallic-like conductivity similar to that observed in synthetic organic conducting polymers such as polyaniline. Detailed physical analysis of the pili, as well as studies in which the structure of the pili was genetically modified, demonstrated that the metallic-like conductivity of the pili could be attributed to overlapping pi-pi orbitals of aromatic amino acids. Other potential mechanisms for conductivity, such as electron hopping between cytochromes associated with the pili were definitively ruled out. Pili were also found to be essential for Fe(III) oxide reduction in G. metallireducens. Ecological studies demonstrated

  4. Microbial Fe(III) Oxide Reduction in Chocolate Pots Hot Springs, Yellowstone National Park

    Science.gov (United States)

    Fortney, N. W.; Roden, E. E.; Boyd, E. S.; Converse, B. J.

    2014-12-01

    Previous work on dissimilatory iron reduction (DIR) in Yellowstone National Park (YNP) has focused on high temperature, low pH environments where soluble Fe(III) is utilized as an electron acceptor for respiration. Much less attention has been paid to DIR in lower temperature, circumneutral pH environments, where solid phase Fe(III) oxides are the dominant forms of Fe(III). This study explored the potential for DIR in the warm (ca. 40-50°C), circumneutral pH Chocolate Pots hot springs (CP) in YNP. Most probable number (MPN) enumerations and enrichment culture studies confirmed the presence of endogenous microbial communities that reduced native CP Fe(III) oxides. Enrichment cultures demonstrated sustained DIR coupled to acetate and lactate oxidation through repeated transfers over ca. 450 days. Pyrosequencing of 16S rRNA genes indicated that the dominant organisms in the enrichments were closely affiliated with the well known Fe(III) reducer Geobacter metallireducens. Additional taxa included relatives of sulfate reducing bacterial genera Desulfohalobium and Thermodesulfovibrio; however, amendment of enrichments with molybdate, an inhibitor of sulfate reduction, suggested that sulfate reduction was not a primary metabolic pathway involved in DIR in the cultures. A metagenomic analysis of enrichment cultures is underway in anticipation of identifying genes involved in DIR in the less well-characterized dominant organisms. Current studies are aimed at interrogating the in situ microbial community at CP. Core samples were collected along the flow path (Fig. 1) and subdivided into 1 cm depth intervals for geochemical and microbiological analysis. The presence of significant quantities of Fe(II) in the solids indicated that DIR is active in situ. A parallel study investigated in vitro microbial DIR in sediments collected from three of the coring sites. DNA was extracted from samples from both studies for 16S rRNA gene and metagenomic sequencing in order to obtain a

  5. Biological Properties of Chloro-salicylidene Aniline and Its Complexes with Co(II) and Cu(II)

    OpenAIRE

    IQBAL, Javed; TIRMIZI, Syed Ahmad; Wattoo,Feroza Hamid; Imran, Muhammad

    2014-01-01

    New complexes of chloro-salicylidene aniline with Co(II) and Cu(II) were synthesised and screened for antibacterial activity against several bacterial strains, namely Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The metal complexes showed enhanced antibacterial activity compared to uncomplexed ligands.

  6. Biological Properties of Chloro-salicylidene Aniline and Its Complexes with Co(II) and Cu(II)

    OpenAIRE

    IQBAL, Javed; TIRMIZI, Syed Ahmad; Wattoo,Feroza Hamid; Imran, Muhammad

    2006-01-01

    New complexes of chloro-salicylidene aniline with Co(II) and Cu(II) were synthesised and screened for antibacterial activity against several bacterial strains, namely Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The metal complexes showed enhanced antibacterial activity compared to uncomplexed ligands.

  7. Kinetic spectrophotometric determination of Co(II ion by the oxidation of Ponceau 4R by hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    SNEZANA B. TOSIC

    2006-02-01

    Full Text Available A new, sensitive and simple kinetic method has been developed for the determination of traces of Co(II ions based on their catalytic effect in the oxidation of trisodium-2-hydroxy-1-(4-sulphonato-1-naphthylazonaphthalene-6,8-disulphonate (red artificial color Ponceau 4R by hydrogen peroxide in borate buffer. The reaction was followed spectrophotometrically by tracing the oxidation product at 478.4 nm within 1 min after the imitation of the reaction. The optimum reaction conditions are: borate buffer (pH = 10.50, Ponceau 4R (8 × 10–6 mol/dm3, H2O2 (3 × 10–2 mol/dm3 at 22 ºC. Following this procedure, Co(II can be determined with a linear calibration graph up to 1.17 ng/cm3 and a detection limit of 0.20, based on the 3s criterion. The relative error ranges between 4.80–3.25 % for the concentration interval of Co(II ions 1.76–17.61 ng/cm3. The effects of certain foreign ions the reaction rate were determined for an assessment of the selectivity of the method. The method was applied for the determination of Co(II in pharmaceutical samples.

  8. Modulation of the coordination environment: a convenient approach to tailor magnetic anisotropy in seven coordinate Co(II) complexes.

    Science.gov (United States)

    Dey, Mamon; Dutta, Snigdha; Sarma, Bipul; Deka, Ramesh Ch; Gogoi, Nayanmoni

    2016-01-14

    The possibility of controlling magnetic anisotropy by tuning contribution of second order perturbation to spin-orbit coupling through modulation of the coordination environment is investigated. Subtle variation of the coordination environment triggers a remarkable deviation in the axial zero field splitting parameter of seven coordinate Co(II) complexes.

  9. Mass spectrometry and potentiometry studies of Pb(II)-, Cd(II)- and Zn(II)-cystine complexes.

    Science.gov (United States)

    Furia, Emilia; Aiello, Donatella; Di Donna, Leonardo; Mazzotti, Fabio; Tagarelli, Antonio; Thangavel, Hariprasad; Napoli, Anna; Sindona, Giovanni

    2014-01-21

    Cd(II)-, Pb(II)- and Zn(II)-cystine complexes were investigated by potentiometric and different mass spectrometric (MS) methodologies. Laser desorption mass spectrometry has provided both the composition and structure of metal-cystine complexes according to the speciation models proposed on the basis of the potentiometric data. Detection of neutral complexes was achieved by protonation or electrochemical reduction during mass spectrometric experiments. The redox activity of metal-cystine complexes was confirmed by laser desorption and charge transfer matrix assisted laser assisted MS experiments, which allowed us to observe the formation of complexes with a reduction of cystine. The stoichiometry of Cd(II)-, Pb(II)- and Zn(II)-cystine complexes was defined by observing the isotopic pattern of the investigated compound. The results suggest that interaction occurs through the carboxylate group of the ligand.

  10. Coadsorption of Cd(II) and oxalate ions at the TiO2/electrolyte solution interface.

    Science.gov (United States)

    Janusz, W; Matysek, M

    2006-04-01

    The study of the adsorptions of cadmium and oxalate ions at the titania/electrolyte interface and the changes of the electrical double layer (edl) structure in this system are presented. The adsorption of cadmium or oxalate ions was calculated from an uptake of their concentration from the solution. The concentration of Cd(II) or oxalate ions in the solution was determined by radiotracer method. For labeling the solution 14C and 115Cd isotopes were used. Coadsorption of Cd(II) and oxalic ions was determined simultaneously. Besides, the main properties of the edl, i.e., surface charge density and zeta potential were determined by potentiometer titration and electrophoresis measurements, respectively. The adsorption of cadmium ions increases with pH increase and shifts with an increase of the initial concentration of Cd(II) ions towards higher pH values. The adsorption process causes an increase of negatively charged sites on anatase and a decrease of the zeta potential with an increase of initial concentration of these ions. The adsorption of oxalate anions at the titania/electrolyte interface proceeds through the exchange with hydroxyl groups. A decrease of pH produces an increase of adsorption of oxalate ions. The processes of anion adsorption lead to increase the number of the positively charged sites at the titania surface. However, specific adsorption of bidenate ligand as oxalate on one surface hydroxyl group may form inner sphere complexes on the metal oxide surface and may overcharge the compact part of the edl. The presence of oxalate ions in the system affects the adsorption of Cd(II) ions on TiO2, increasing the adsorption at low pH range and decreasing the adsorption at high pH range. Using adsorption as a function of pH data, some characteristic parameters of adsorption envelope were calculated.

  11. Mn(II), Co(II), Zn(II), Fe(III) and U (VI) complexes of 2-acetylpyridine 4N-(2-pyridyl) thiosemicarbazone (HAPT); structural, spectroscopic and biological studies

    Science.gov (United States)

    El-Ayaan, Usama; Youssef, Magdy M.; Al-Shihry, Shar

    2009-11-01

    The present work carried out a study on transition metal ion complexes which have been synthesized from 2-acetylpyridine 4N-(2-pyridyl) thiosemicarbazone (HAPT) 1. These complexes namely [Zn(HAPT)Cl 2] 2, [Mn (HAPT)Cl 2] 3, [Co (HAPT)Cl 2] 4, [Fe(APT)Cl 2(H 2O)] 5 and [UO 2(HAPT)(OAc) 2] 6, were characterized by elemental analysis, spectral (IR, 1H NMR and UV-vis) and magnetic moment measurements. Thermal properties and decomposition kinetics of all compounds are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters ( E, A, Δ H, Δ S and Δ G) of all thermal decomposition stages have been evaluated using Coats-Redfern equation. The biochemical studies showed that, complexes 3 and 6 have powerful and complete degradation effect on the both DNA and protein. The SOD-like activity exhibited that complex 3 has a strong antioxidative properties. The antibacterial screening demonstrated that, the free ligand (HAPT), complexes 2, 3 and 6 have the maximum and broad activities against Gram-positive and Gram-negative bacterial strains.

  12. Removal of Pb(II), Cd(II), Cu(II) and trichloroethylene from water by Nanofer ZVI.

    Science.gov (United States)

    Eglal, Mahmoud M; Ramamurthy, Amruthur S

    2015-01-01

    Zero-valent iron nanoparticle (Nanofer ZVI) is a new reagent due to its unique structure and properties. Images of scanning electron microscopy/electron dispersive spectroscopy (SEM/EDS), transmission electron microscopy and X-ray diffraction revealed that Nanofer ZVI is stable, reactive and has a unique structure. The particles exhibited a spherical shape, a chain-like structure with a particle size of 20 to 100 nm and a surface area between 25-30 m2g(-1). The time interval for particles to agglomerate and settle was between 4-6 h. SEM/EDS Images showed that particle size increased to 2 µm due to agglomeration. Investigation of adsorption and oxidation behavior of Nanofer ZVI used for the removal of Cu(II), Pb(II), Cd(II) ions and trichloroethylene (TCE) from aqueous solutions showed that the optimal pH for Pb(II), Cu(II), Cd(II) and TCE removal were 4.5 and 4.8, 5.0 and 6.5, respectively. Test data were used to form Langmuir and Freundlich isotherms. The maximum contaminant loading was estimated as 270, 170, 110, 130 mg per gram of Nanofer ZVI for Cu(II), Pb(II), Cd(II) and TCE respectively. Removal of metal ions is interpreted in terms of their hydrated ionic radii and their electronegativity. TCE oxidation followed the dechlorination pathway resulting in nonhazardous by-products.

  13. Variable primary coordination environments of Cd(II) binding to three helix bundles provide a pathway for rapid metal exchange.

    Science.gov (United States)

    Tebo, Alison G; Hemmingsen, Lars; Pecoraro, Vincent L

    2015-12-01

    Members of the ArsR/SmtB family of transcriptional repressors, such as CadC, regulate the intracellular levels of heavy metals like Cd(II), Hg(II), and Pb(II). These metal sensing proteins bind their target metals with high specificity and affinity, however, a lack of structural information about these proteins makes defining the coordination sphere of the target metal difficult. Lingering questions as to the identity of Cd(II) coordination in CadC are addressed via protein design techniques. Two designed peptides with tetrathiolate metal binding sites were prepared and characterized, revealing fast exchange between CdS3O and CdS4 coordination spheres. Correlation of (111m)Cd PAC spectroscopy and (113)Cd NMR spectroscopy suggests that Cd(II) coordinated to CadC is in fast exchange between CdS3O and CdS4 forms, which may provide a mechanism for rapid sensing of heavy metal contaminants by this regulatory protein.

  14. Adsorbent-adsorbate interactions in the adsorption of Cd(II) and Hg(II) on ozonized activated carbons.

    Science.gov (United States)

    Sánchez-Polo, M; Rivera-Utrilla, J

    2002-09-01

    The present work investigated the effect of surface oxygenated groups on the adsorption of Cd(II) and Hg(II) by activated carbon. A study was undertaken to determine the adsorption isotherms and the influence of the pH on the adsorption of each metallic ion by a series of ozonized activated carbons. In the case of Cd(II), the adsorption capacity and the affinity of the adsorbent augmented with the increase in acid-oxygenated groups on the activated carbon surface. These results imply that electrostatic-type interactions predominate in this adsorption process. The adsorption observed at solution pH values below the pH(PZC) of the carbon indicates that other forces also participate in this process. Ionic exchange between -C pi-H3O+ interaction protons and Cd(II) ions would account for these findings. In the case of Hg(II), the adsorption diminished with an increase in the degree of oxidation of the activated carbon. The presence of electron-withdrawing groups on oxidized carbons decreases the electronic density of their surface, producing a reduction in the adsorbent-adsorbate dispersion interactions and in their reductive capacity, thus decreasing the adsorption of Hg(II) on the activated carbon. At pH values above 3, the pH had no influence on the adsorption of Hg(II) by the activated carbon, confirming that electrostatic interactions do not have a determinant influence on Hg(II) adsorption.

  15. Comparison of adsorption of Cd(II and Pb(II ions on pure and chemically modified fly ashes

    Directory of Open Access Journals (Sweden)

    Sočo Eleonora

    2016-06-01

    Full Text Available The study investigates chemical modifications of coal fly ash (FA treated with HCl or NH4HCO3 or NaOH or Na2edta, based on the research conducted to examine the behaviour of Cd(II and Pb(II ions adsorbed from water solution on treated fly ash. In laboratory tests, the equilibrium and kinetics were examined applying various temperatures (293 - 333 K and pH (2 - 11 values. The maximum Cd(II and Pb(II ions adsorption capacity obtained at 293 K, pH 9 and mixing time 2 h from the Langmuir model can be grouped in the following order: FA-NaOH > FA-NH4HCO3 > FA > FA-Na2edta > FA-HCl. The morphology of fly ash grains was examined via small-angle X-ray scattering (SAXS and images of scanning electron microscope (SEM. The adsorption kinetics data were well fitted by a pseudo-second-order rate model but showed a very poor fit for the pseudofirst order model. The intra-particle model also revealed that there are two separate stages in the sorption process, i.e. the external diffusion and the inter-particle diffusion. Thermodynamics parameters such as free energy, enthalpy and entropy were also determined. A laboratory test demonstrated that the modified coal fly ash worked well for the Cd(II and Pb(II ion uptake from polluted waters.

  16. Cd(II and Pb(II complexes of the polyether ionophorous antibiotic salinomycin

    Directory of Open Access Journals (Sweden)

    Tanabe Makoto

    2011-09-01

    Full Text Available Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II ions in in vivo experiments, despite so far no Pb(II-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II and lead(II. Results New metal(II complexes of the polyether ionophorous antibiotic salinomycin with Cd(II and Pb(II ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa undergoes a reaction with heavy metal(II ions to form [Cd(Sal2(H2O2] (1 and [Pb(Sal(NO3] (2, respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock

  17. Semi-interpenetrating hybrid membranes containing ADOGEN{sup ®} 364 for Cd(II) transport from HCl media

    Energy Technology Data Exchange (ETDEWEB)

    Mora-Tamez, Lucía; Rodríguez de San Miguel, Eduardo; Briones-Guerash, Ulrich; Munguía-Acevedo, Nadia M.; Gyves, Josefina de, E-mail: degyves@unam.mx

    2014-09-15

    Graphical abstract: - Highlights: • Semi-interpenetrating hybrid membranes are used for quantitative cadmium(II) recovery. • Optimization of membrane and solutions compositions is performed. • Membranes present increased stability respect to polymer inclusion membranes. • Models for cadmium (II) extraction and transport are proposed. • Excellent selectivity for Cd(II) over Ni(II), Cu(II) and Pb(II) was achieved. - Abstract: Cd(II) transport from 1 mol dm{sup −3} HCl media was investigated across semi-interpenetrating hybrid membranes (SIHMs) that were prepared by mixing an organic matrix composed of ADOGEN{sup ®} 364 as an extracting agent, cellulose triacetate as a polymeric support and nitrophenyloctyl ether as a plasticizer with an organic/inorganic network (silane phase, SP) composed of polydimethylsiloxane and a crosslinking agent. The stripping phase used was a 10{sup −2} mol dm{sup −3} ethanesulfonic acid solution. The effects of tetraorthoethoxysilane, phenyltrimethoxysilane and N′,N′-bis[3-tri(methoxysilyl)propyl]ethylendiamine as crosslinking agents on the transport were studied. H{sub 3}PO{sub 4} was used as an acid catalyst during the SP synthesis and optimized for transport performance. Solid–liquid extraction experiments were performed to determine the model that describe the transport of Cd(II) via ADOGEN{sup ®} 364. The transport was found to be chained-carrier controlled with a percolation threshold of 0.094 mmol g{sup −1}. The selective recovery of Cd(II) was studied with respect to Ni(II), Zn(II), Cu(II), and Pb(II) at a 1:1 molar ratio, and the optimized membrane system was applied for the recovery of Cd(II) from a real sample consisting of a Ni/Cd battery with satisfactory results. Finally, stability experiments were performed using the same membrane for 14 cycles. The results obtained showed that SIHMs had excellent stability and selectivity, with permeabilities comparable to those of PIMs.

  18. Bioavailability of Fe(III) in Natural Soils and the Impact on Mobility of Inorganic Contaminants (Final Report)

    Energy Technology Data Exchange (ETDEWEB)

    Kosson, David S. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Civil and Environmental Engineering; Cowan, Robert M. [Rutgers Univ., New Brunswick, NJ (United States). Dept. of Environmental Science; Young, Lily Y. [Rutgers Univ., New Brunswick, NJ (United States). Center for Agriculture and the Environment; Hatcherl, Eric L. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Civil and Environmental Engineering; Scala, David J. [Vanderbilt Univ., Nashville, TN (United States). Dept. of Civil and Environmental Engineering

    2005-08-02

    Inorganic contaminants, such as heavy metals and radionuclides, can adhere to insoluble Fe(III) minerals resulting in decreased mobility of these contaminants through subsurface environments. Dissimilatory Fe(III)-reducing bacteria (DIRB), by reducing insoluble Fe(III) to soluble Fe(II), may enhance contaminant mobility. The Savannah River Site, South Carolina (SRS), has been subjected to both heavy metal and radionuclide contamination. The overall objective of this project is to investigate the release of inorganic contaminants such as heavy metals and radionuclides that are bound to solid phase soil Fe complexes and to elucidate the mechanisms for mobilization of these contaminants that can be associated with microbial Fe(III) reduction. This is being accomplished by (i) using uncontaminated and contaminated soils from SRS as prototype systems, (ii) evaluating the diversity of DIRBs within the samples and isolating cultures for further study, (iii) using batch microcosms to evaluate the bioavailability of Fe(III) from pure minerals and SRS soils, (iv) developing kinetic and mass transfer models that reflect the system dynamics, and (v) carrying out soil column studies to elucidate the dynamics and interactions amongst Fe(III) reduction, remineralization and contaminant mobility.

  19. The interaction of phenolic acids with Fe(III) in the presence of citrate as studied by isothermal titration calorimetry.

    Science.gov (United States)

    Yang, Senpei; Bai, Guangling; Chen, Lingli; Shen, Qun; Diao, Xianmin; Zhao, Guanghua

    2014-08-15

    Under physiological conditions, exogenous chelators such as polyphenols might interact with non-protein bound ferric complexes, such as Fe(III)-citrate. Additionally, Fe(III) and citrate are widely distributed in various fruits and vegetables which are also rich in phenolic acids. In this study, we focus on the interaction between phenolic acids (gallic acid, methyl gallate and protocatechuic acid) and Fe(III) in the presence of excessive citrate by isothermal titration calorimetry (ITC) for thermodynamic studies, and stopped-flow absorption spectrometry for fast kinetic studies. Results reveal that all of these three phenolic acids can bind to the Fe(III) with the same stoichiometry (3:1). Moreover, the binding constants of these three compounds with Fe(III) are greatly dependent on ligand structure, and are much higher than that of Fe(III)-citrate. Based on their stoichiometry and superhigh binding constants, it is most likely that these three phenolic acids can displace the citrate to bind with one iron(III) ion to form a stable octahedral geometric structure, albeit at different rates. These findings shed light on the interaction between phenolic acids and Fe(III) in the presence of citrate under either physiological conditions or in a food system.

  20. Carbon dots preparation as a fluorescent sensing platform for highly efficient detection of Fe(III) ions in biological systems.

    Science.gov (United States)

    Hamishehkar, Hamed; Ghasemzadeh, Bahar; Naseri, Abdolhossein; Salehi, Roya; Rasoulzadeh, Farzaneh

    2015-01-01

    Water-soluble carbon dots (CDs) were prepared, using a facile hydrothermal oxidation route of cyclic oligosaccharide α-CD, as carbon sources, and alkali as additives. The successful synthesis of CDs was confirmed by scanning electron microscopy (SEM), dynamic light scattering (DLS), FTIR, UV-visible absorption, and emission fluorescence. The characterizations showed that the prepared CDs are spherical and well-dispersed in water with average diameters of approximately 2 nm. These water-soluble CDs have excellent photo stability towards photo bleaching during 30 days. The obtained CDs showed a strong emission at the wavelength of 450 nm, with an optimum excitation of 360 nm. The fluorescence quenching of CDs in the presence of Fe(III) ions was used as fluorescent probes for quantifying Fe(III) ions in aqueous solution. Under optimum condition, the fluorescence intensity versus Fe(III) concentration gave a linear response, according to Stern-Volmer equation. The linearity range of the calibration curve and the limit of detection were 1.60×10(-5) to 16.6×10(-5) mol L(-1), and 6.05×10(-6) mol L(-1), respectively, which was in the range for serum analysis of Fe(III). It was concluded that the prepared CDs had a great potential as fluorescent probes for applications in analysis of Fe(III) ions in the blood serum samples, which is hardly interfered by other ions.

  1. Adsorption of Cd(II), Cu(II) and Ni(II) ions by cross-linking chitosan/rectorite nano-hybrid composite microspheres.

    Science.gov (United States)

    Zeng, Lixuan; Chen, Yufei; Zhang, Qiuyun; Guo, Xingmei; Peng, Yanni; Xiao, Huijuan; Chen, Xiaocheng; Luo, Jiwen

    2015-10-05

    Chitosan/rectorie (CTS/REC) nano-hybrid composite microsphere was prepared by changing the proportion of CTS/REC with 2:1, 3:1 and 4:1. Compared with the pure cross-linking chitosan microsphere, the nano-hybrid composite microsphere was proved to have better sorption capacity of Cd(II), Cu(II) and Ni(II), especially 2:1(CTS/REC-1). The adsorption behavior of the microsphere of Cd(II), Cu(II) and Ni(II) was investigated in single and binary metal systems. In single system, the equilibrium studies showed that the adsorption of Cd(II), Cu(II) and Ni(II) followed the Langmuir model and the pseudo-second-order kinetic model. The negative values of (ΔG) suggested that the adsorption process was spontaneous. In binary system, the combined action of the metals was found to be antagonistic and the metal sorption followed the order of Cu(II)>Cd(II)>Ni(II). The regeneration studies indicated that EDTA desorbed Cd(II), Cu(II) and Ni(II) from cross-linking microspheres better than HCl. The FT-IR and XPS spectra showed that coordination bonds were formed between Cd(II), Cu(II) and Ni(II) and the nitrogen atoms of cross-linking CTS/REC nano-hybrid composite microspheres.

  2. Synthesis and characterization of hydroxyapatite nanoparticles impregnated on apple pomace to enhanced adsorption of Pb(II), Cd(II), and Ni(II) ions from aqueous solution.

    Science.gov (United States)

    Chand, Piar; Pakade, Yogesh B

    2015-07-01

    Hydroxyapatite nanoparticles were synthesized, characterized, and impregnated onto apple pomace surface (HANP@AP) for efficient removal of Pb(II), Cd(II), and Ni(II) ions from water. HANP@AP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD), and surface area analysis. Batch sorption studies were carried out to investigate the influence of different parameters as amount of dose (g), pH, time (min), and initial concentration (mg L(-1)) on adsorption process. Experimental kinetic data followed pseudo-second-order model and equilibrium data well fitted to Langmuir adsorption model with maximum adsorption capacities of 303, 250, and 100 mg g(-1) for Pb(II), Cd(II), and Ni(II) ions, respectively. Competitive adsorption of Pb(II), Cd(II), and Ni(II) ions in presences of each other was studied to evaluate the removal efficiency of HANP@AP against multi metal-loaded water. HANP@AP was successfully applied to real industrial wastewater with 100 % removal of all three metal ions even at high concentration. HANP@AP could be recycled for four, four, and three cycles in case of Pb(II), Cd(II) and Ni(II), respectively. The study showed that HANP@AP is fast, cost effective, and environmental friendly adsorbent for removal of Pb(II), Cd(II), and Ni(II) ions from real industrial wastewater.

  3. Photochemical Formation of Fe(II) in the Aqueous Solutions of Fe(III)- Dicarboxylates

    Science.gov (United States)

    Okada, K.; Arakaki, T.

    2007-12-01

    Although there have been many studies reporting the photochemical formation of Fe(II) in various aqueous-phase such as rain, cloud waters, seawater and aerosols, the detailed formation mechanisms are not well understood. To better understand the mechanisms of Fe(II) formation, we attempted to determine the molar absorptivity and the quantum yield of Fe(II) photoformation for individual Fe(III)-dicarboxylate species. The concentrations of Fe(II) and total dissolved Fe were measured by a Ferrozine-HPLC method. The Visual MINTEQ computer program was used to calculate the equilibrium concentrations of chemical species in the solutions of Fe(III)-dicarboxylate complexes. The molar absorptivity and the product of the quantum yield and the molar absorptivity of Fe(III)- dicarboxylate complex can be analysed by UV-VIS spectrophotometer and photochemical experiments, and these experimental data were combined with the calculated equilibrium Fe(III) speciation to determine individual molar absorptivity and quantum yield of Fe(II) photoformation for a specific Fe(III)-dicarboxylate complex. Preliminary results, using an oxalate whose quantum yield has been previously reported, indicate that this approach gives lower quantum yield values in air saturated solutions than previously reported.

  4. Biogenic Fe(III) minerals lower the efficiency of iron-mineral-based commercial filter systems for arsenic removal.

    Science.gov (United States)

    Kleinert, Susanne; Muehe, Eva M; Posth, Nicole R; Dippon, Urs; Daus, Birgit; Kappler, Andreas

    2011-09-01

    Millions of people worldwide are affected by As (arsenic) contaminated groundwater. Fe(III) (oxy)hydroxides sorb As efficiently and are therefore used in water purification filters. Commercial filters containing abiogenic Fe(III) (oxy)hydroxides (GEH) showed varying As removal, and it was unclear whether Fe(II)-oxidizing bacteria influenced filter efficiency. We found up to 10(7) Fe(II)-oxidizing bacteria/g dry-weight in GEH-filters and determined the performance of filter material in the presence and absence of Fe(II)-oxidizing bacteria. GEH-material sorbed 1.7 mmol As(V)/g Fe and was ~8 times more efficient than biogenic Fe(III) minerals that sorbed only 208.3 μmol As(V)/g Fe. This was also ~5 times more efficient than a 10:1-mixture of GEH-material and biogenic Fe(III) minerals that bound 322.6 μmol As(V)/g Fe. Coprecipitation of As(V) with biogenic Fe(III) minerals removed 343.0 μmol As(V)/g Fe, while As removal by coprecipitation with biogenic minerals in the presence of GEH-material was slightly less efficient as GEH-material only and yielded 1.5 mmol As(V)/g Fe. The present study thus suggests that the formation of biogenic Fe(III) minerals lowers rather than increases As removal efficiency of the filters probably due to the repulsion of the negatively charged arsenate by the negatively charged biogenic minerals. For this reason we recommend excluding microorganisms from filters (e.g., by activated carbon filters) to maintain their high As removal capacity.

  5. Spectroscopic, thermal and antibacterial studies on Mn(II and Co(II complexes derived from thiosemicarbazone

    Directory of Open Access Journals (Sweden)

    SULEKH CHANDRA

    2009-08-01

    Full Text Available Mn(II and Co(II complexes having the general composition [M(L2X2] (where L = 2-pyridinecarboxaldehyde thiosemicarbazone, M = Mn(II and Co(II, X = Cl- and NO3- were synthesized. All the metal complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, mass, IR, EPR, electronic spectral studies and thermogravimetric analysis (TG. Based on the spectral studies, an octahedral geometry was assigned for all the complexes. Thermal studies of the compounds suggest that the complexes are more stable than the free ligand. This fact was supported by the kinetic parameters calculated using the Horowitz–Metzger (H–M and Coats–Redfern (C–R equations. The antibacterial properties of the ligand and its metal complexes were also examined and it was observed that the complexes are more potent bactericides than the free ligand.

  6. OmcB, a c-Type Polyheme Cytochrome, Involved in Fe(III) Reduction in Geobacter sulfurreducens

    OpenAIRE

    2003-01-01

    Microorganisms in the family Geobacteraceae are the predominant Fe(III)-reducing microorganisms in a variety of subsurface environments in which Fe(III) reduction is an important process, but little is known about the mechanisms for electron transport to Fe(III) in these organisms. The Geobacter sulfurreducens genome was found to contain a 10-kb chromosomal duplication consisting of two tandem three-gene clusters. The last genes of the two clusters, designated omcB and omcC, encode putative o...

  7. Preparation and studies of Co(II) and Co(III)-substituted barium ferrite prepared by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Teh, Geok Bee [Department of Bioscience and Chemistry, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 53300 Kuala Lumpur (Malaysia)]. E-mail: tehgb@mail.utar.edu.my; Nagalingam, Saravanan [Department of Bioscience and Chemistry, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, 53300 Kuala Lumpur (Malaysia); Jefferson, David A. [Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW (United Kingdom)

    2007-01-15

    The sol-gel preparative method was employed to synthesise Co(II) and Co(III)-substituted barium ferrite. This method was attempted to achieve higher homogeneity of the final product. Samples of substituted ferrites were characterised by various experimental techniques including high resolution transmission electron microscopy, X-ray diffraction analysis, magnetometry and thermal gravimetric analysis. The microstructural changes induced by such substitution are also discussed.

  8. Synthesis, structures and photocatalytic properties of two new Co(II) coordination polymers based on 5-(benzyloxy)isophthalate ligand

    Science.gov (United States)

    Li, Xia; Li, Jing; Li, Ming-Kai; Fei, Zhou

    2014-02-01

    Two new Co(II) coordination polymer, namely [Co2(L)2(H2O)]n (1) and [Co(L)(phen)(H2O)]n·xH2O (2) (H2L = 5-(benzyloxy)isophthalic acid, phen = 1,10-phenanthroline) have been hydrothermally synthesized and characterized by elemental analysis, powder X-ray diffraction, thermal analysis and single crystal X-ray analysis. The molecular structure of 1 contains two Co(II) ions, two L2- ligands and one coordinated water molecule, which further extends into a complicated 3D framework with the tails of L2- ligands filling in the hexagonal channels, and the molecular structure of 2 contains one Co(II) ions, one L2- ligands, one phen ligands, one coordinated water molecule and half of the water molecule of crystallization, which further extends into a 1D chain structure. In addition, photocatalytic investigation on compounds 1 and 2 reveals that they are active catalyst for degradation of methyl blue.

  9. Binuclear Cu(II and Co(II Complexes of Tridentate Heterocyclic Shiff Base Derived from Salicylaldehyde with 4-Aminoantipyrine

    Directory of Open Access Journals (Sweden)

    Omar Hamad Shihab Al-Obaidi

    2012-01-01

    Full Text Available New binuclear Co(II and Co(II complexes of ONO tridentate heterocyclic Schiff base derived from 4-aminoantipyrine with salicylaldehyde have been synthesized and characterized on the bases of elemental analysis, UV-Vis., FT-IR, and also by aid of molar conductivity measurements, magnetic measurements, and melting points. It has been found that the Schiff bases with Cu(II or Co(II ion forming binuclear complexes on (1 : 1 “metal : ligand” stoichiometry. The molar conductance measurements of the complexes in DMSO correspond to be nonelectrolytic nature for all prepared complexes. Distorted octahedral environment is suggested for metal complexes. A theoretical treatment of the formation of complexes in the gas phase was studied, and this was done by using the HyperChem-6 program for the molecular mechanics and semi-empirical calculations. The free ligand and its complexes have been tested for their antibacterial activities against two types of human pathogenic bacteria: the first type (Staphylococcus aureus is Gram positive and the second type (Escherichia coli is Gram negative (by using agar well diffusion method. Finally, it was found that compounds show different activity of inhibition on growth of the bacteria.

  10. Synthesis, spectroscopic, fluorescence properties and biological evaluation of novel Pd(II) and Cd(II) complexes of NOON tetradentate Schiff bases.

    Science.gov (United States)

    Ali, Omyma A M

    2014-01-01

    The solid complexes of Pd(II) and Cd(II) with N,N/bis(salicylaldehyde)4,5-dimethyl-1,2-phenylenediamine (H2L(1)), and N,N/bis(salicylaldehyde)4,5-dichloro-1,2-phenylenediamine (H2L(2)) have been synthesized and characterized by several techniques using elemental analysis (CHN), FT-IR, (1)H NMR, UV-Vis spectra and thermal analysis. Elemental analysis data proved 1:1 stoichiometry for the reported complexes while spectroscopic data indicated square planar and octahedral geometries for Pd(II) and Cd(II) complexes, respectively. The prepared ligands, Pd(II) and Cd(II) complexes exhibited intraligand (π-π(∗)) fluorescence and can potentially serve as photoactive materials. Thermal behavior of the complexes was studied and kinetic parameters were determined by Coats-Redfern method. Both the ligands and their complexes have been screened for antimicrobial activities.

  11. Synthesis, crystal structure, spectral characterization and photoluminescence property of three Cd(II) complexes with a pyrazole based Schiff-base ligand

    Science.gov (United States)

    Mandal, Susmita; Saha, Rajat; Saha, Manan; Pradhan, Rajesh; Butcher, Ray J.; Saha, Nitis Chandra

    2016-04-01

    Substituted pyrazole containing Schiff-base ligand, 5-methyl-3-formylpyrazole-N-(2‧-methylphenoxy)methyleneimine, (MPzOA), afforded three new Cd(II) complexes, [Cd(MPzOA)Cl2]2.CH3OH (I), [Cd(MPzOA)2(H2O)2](ClO4)2 (II) and [Cd(MPzOA)(H2O)(NO3)2] (III). In the reported complex species the coordination number and geometry of Cd(II) vary. In complex I and II, Cd(II) adopts six and in (III) it adopts eight coordination modes, with prismatic, octahedral and distorted dodecahedral geometry, respectively. All the complexes are characterized by IR, 1H NMR, UV-Vis spectral parameters and X-ray analyses. The complexes have 1D, 2D and 3D supramolecular frameworks formed by non-covalent interactions, like hydrogen bonding, π … π stacking, C-H … π interactions.

  12. Equilibrium and kinetic modelling of Cd(II) biosorption by algae Gelidium and agar extraction algal waste.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2006-01-01

    In this study an industrial algal waste from agar extraction has been used as an inexpensive and effective biosorbent for cadmium (II) removal from aqueous solutions. This biosorbent was compared with the algae Gelidium itself, which is the raw material for agar extraction. Equilibrium data follow both Langmuir and Redlich-Peterson models. The parameters of Langmuir equilibrium model are q(max)=18.0 mgg(-1), b=0.19 mgl(-1) and q(max)=9.7 mgg(-1), b=0.16 mgl(-1), respectively for Gelidium and the algal waste. Kinetic experiments were conducted at initial Cd(II) concentrations in the range 6-91 mgl(-1). Data were fitted to pseudo-first- and second-order Lagergren models. For an initial Cd(II) concentration of 91 mgl(-1) the parameters of the pseudo-first-order Lagergren model are k(1,ads)=0.17 and 0.87 min(-1); q(eq)=16.3 and 8.7 mgg(-1), respectively, for Gelidium and algal waste. Kinetic constants vary with the initial metal concentration. The adsorptive behaviour of biosorbent particles was modelled using a batch reactor mass transfer kinetic model. The model successfully predicts Cd(II) concentration profiles and provides significant insights on the biosorbents performance. The homogeneous diffusivity, D(h), is in the range 0.5-2.2 x10(-8) and 2.1-10.4 x10(-8)cm(2)s(-1), respectively, for Gelidium and algal waste.

  13. Tartrazine modified activated carbon for the removal of Pb(II), Cd(II) and Cr(III).

    Science.gov (United States)

    Monser, Lotfi; Adhoum, Nafaâ

    2009-01-15

    A two in one attempt for the removal of tartrazine and metal ions on activated carbon has been developed. The method was based on the modification of activated carbon with tartrazine then its application for the removal of Pb(II), Cd(II) and Cr(III) ions at different pH values. Tartrazine adsorption data were modelled using both Langmuir and Freundlich classical adsorption isotherms. The adsorption capacities qm were 121.3, 67 and 56.7mgg(-1) at initial pH values of 1.0, 6.0 and 10, respectively. The adsorption of tartrazine onto activated carbon followed second-order kinetic model. The equilibrium time was found to be 240min at pH 1.0 and 120min at pH 10 for 500mgL(-1) tartrazine concentration. A maximum removal of 85% was obtained after 1h of contact time. The presence of tartrazine as modifier enhances attractive electrostatic interactions between metal ions and carbon surface. The adsorption capacity for Pb(II), Cd(II) and Cr(III) ions has been improved with respect to non-modified carbon reaching a maximum of 140%. The adsorption capacity was found to be a pH dependent for both modified and non-modified carbon with a greater adsorption at higher pH values except for Cr(III). The enhancement percent of Pb(II), Cd(II) and Cr(III) at different pH values was varied from 28% to 140% with respect to non-modified carbon. The amount of metal ions adsorbed using static regime was 11-40% higher than that with dynamic mode. The difference between adsorption capacities could be attributed to the applied flow rate.

  14. Metal-Assisted Oxo Atom Addition to an Fe(III) Thiolate.

    Science.gov (United States)

    Villar-Acevedo, Gloria; Lugo-Mas, Priscilla; Blakely, Maike N; Rees, Julian A; Ganas, Abbie S; Hanada, Erin M; Kaminsky, Werner; Kovacs, Julie A

    2017-01-11

    Cysteinate oxygenation is intimately tied to the function of both cysteine dioxygenases (CDOs) and nitrile hydratases (NHases), and yet the mechanisms by which sulfurs are oxidized by these enzymes are unknown, in part because intermediates have yet to be observed. Herein, we report a five-coordinate bis-thiolate ligated Fe(III) complex, [Fe(III)(S2(Me2)N3(Pr,Pr))](+) (2), that reacts with oxo atom donors (PhIO, IBX-ester, and H2O2) to afford a rare example of a singly oxygenated sulfenate, [Fe(III)(η(2)-S(Me2)O)(S(Me2))N3(Pr,Pr)](+) (5), resembling both a proposed intermediate in the CDO catalytic cycle and the essential NHase Fe-S(O)(Cys114) proposed to be intimately involved in nitrile hydrolysis. Comparison of the reactivity of 2 with that of a more electron-rich, crystallographically characterized derivative, [Fe(III)S2(Me2)N(Me)N2(amide)(Pr,Pr)](-) (8), shows that oxo atom donor reactivity correlates with the metal ion's ability to bind exogenous ligands. Density functional theory calculations suggest that the mechanism of S-oxygenation does not proceed via direct attack at the thiolate sulfurs; the average spin-density on the thiolate sulfurs is approximately the same for 2 and 8, and Mulliken charges on the sulfurs of 8 are roughly twice those of 2, implying that 8 should be more susceptible to sulfur oxidation. Carboxamide-ligated 8 is shown to be unreactive towards oxo atom donors, in contrast to imine-ligated 2. Azide (N3(-)) is shown to inhibit sulfur oxidation with 2, and a green intermediate is observed, which then slowly converts to sulfenate-ligated 5. This suggests that the mechanism of sulfur oxidation involves initial coordination of the oxo atom donor to the metal ion. Whether the green intermediate is an oxo atom donor adduct, Fe-O═I-Ph, or an Fe(V)═O remains to be determined.

  15. Phylogenetics and Srf Analysis of Mitochondrial DNA COII Gene in Anopheles Species (Diptera: Culicidae

    Directory of Open Access Journals (Sweden)

    Monika Sharma

    2011-07-01

    Full Text Available Mitochondrial DNA COII gene was used to study the interspecific variation and molecular analysis among six species of genus Anopheles belonging to subgenus Cellia i.e. An. stephensi, An. culicifacies, An. maculatus, An. subpictus, An. annularis and An. splendidus. The sequence was found to be AT rich with maximum of 75.07% in An. culicifacies. The sequence analysis revealed the number of transversions to be more than transitions which is opposite of the general contention with transitions being more frequent than transversions in mitochondrial genes. However, among the Anopheles species, the maximum number of substitutions was found in An. maculatus. The phylogenetic analysis using the three methods MP, ML and NJ methods was also carried out for which Cx. quinquefasciatus was taken as outgroup. Analysis showed that An. stephensi and An. culicifacies shared a close genetic homology while An. annularis and An. splendidus made another group with identical genetic qualities. To the contrary, An. subpictus and An. maculatus had hypervariable non-homologous genomic qualities. Short tandem as well as nontandem repeats were also studied using SRF (Spectral Repeat Finder programme. The repeats were conserved in all the species except certain polymorphic repeats such as TAT and TTTAT were present in An. stephensi whereas no polymorphic repeats were present in An. subpictus. Identification of repeats is crucial to shed light on the function and structure of proteins, and explain their evolutionary past.

  16. Penicillamine-modified sensor for the voltammetric determination of Cd(II) and Pb(II) ions in natural samples.

    Science.gov (United States)

    Pérez-Ràfols, Clara; Serrano, Núria; Díaz-Cruz, José Manuel; Ariño, Cristina; Esteban, Miquel

    2015-11-01

    A new penicillamine-GCE was developed based on the immobilization of d-penicillamine on aryl diazonium salt monolayers anchored to the glassy carbon electrode (GCE) surface and it was applied for the first time to the simultaneous determination of Cd(II) and Pb(II) ions by stripping voltammetric techniques. The detection and quantification limits at levels of µg L(-1) suggest that the penicillamine-GCE could be fully suitable for the determination of the considered ions in natural samples.

  17. Heterocyclic tri-urea isocyanurate bridged groups modified periodic mesoporous organosilica synthesized for Fe(III) adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Vijay Kumar [Department of Polymer Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Department of Chemical Technology, North Maharashtra University Jalgaon-425001 (India); Division of Polymer Science and Engineering, National Chemical Laboratory, Pune-411 008 (India); Selvaraj, M. [Department of Chemical and Biomolecular Engineering, Pusan National University, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Parambadath, Surendran; Chu, Sang-Wook; Park, Sung Soo [Department of Polymer Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of); Mishra, Satyendra [Department of Chemical Technology, North Maharashtra University Jalgaon-425001 (India); Singh, Raj Pal [Division of Polymer Science and Engineering, National Chemical Laboratory, Pune-411 008 (India); Ha, Chang-Sik, E-mail: csha@pnu.edu [Department of Polymer Science and Engineering, Pusan National University, Busan 609-735 (Korea, Republic of)

    2012-10-15

    To achieve a high level of heavy metal adsorption, 1,1 Prime ,1 Double-Prime -(1,3,5-triazine-2,4,6-triyl)tris(3-(3-(triethoxysilyl)propyl)urea) (TTPU) was synthesized as a novel melamine precursor and incorporated on the silica surface of periodic mesoporous organosilica (PMO). The melamine modified PMOs (MPMOs) were synthesized under acidic conditions using TTPU, tetraethylorthosilicate (TEOS) and Pluronic P123 as a template and the modified PMOs were characterized using the relevant instrumental techniques. The characteristic materials were used as adsorbents for the adsorption of Fe(III) ions. Fe(III) adsorption studies revealed MPMO-7.5 to be a good absorbent with higher adsorption efficiency than other MPMOs. - Graphical Abstract: A new organosilica precursor, TTPU, has been successfully synthesized and characterized to incorporate on the silica surface of periodic mesoporous organosilica (PMO). The melamine modified PMOs (MPMOs), in particular, the MPMO-7.5 was found to exhibit good adsorption efficiency for Fe(III). Highlights: Black-Right-Pointing-Pointer Synthesis of new melamine modified periodic mesoporous organosilicas (MPMOs). Black-Right-Pointing-Pointer A new organosilica precursor, TTPU, has been successfully synthesized for the MPMOs. Black-Right-Pointing-Pointer The MPMOs were characterized by the relevant instrumental techniques. Black-Right-Pointing-Pointer MPMO-7.5 exhibits higher adsorption efficiency for Fe(III) ions than other MPMOs.

  18. Bacteria attenuation by iron electrocoagulation governed by interactions between bacterial phosphate groups and Fe(III) precipitates

    NARCIS (Netherlands)

    Delaire, Caroline; van Genuchten, Case M.; Amrose, Susan E.; Gadgil, Ashok J.

    2016-01-01

    Iron electrocoagulation (Fe-EC) is a low-cost process in which Fe(II) generated from an Fe(0) anode reacts with dissolved O2 to form (1) Fe(III) precipitates with an affinity for bacterial cell walls and (2) bactericidal reactive oxidants. Previous work suggests that Fe-EC is a promising treatment o

  19. A comparative study for the ion exchange of Fe(III) and Zn(II) on zeolite NaY.

    Science.gov (United States)

    Ostroski, Indianara C; Barros, Maria A S D; Silva, Edson A; Dantas, João H; Arroyo, Pedro A; Lima, Oswaldo C M

    2009-01-30

    The uptake capacity of Fe(III) and Zn(II) ions in NaY zeolite was investigated. Experiments were carried out in a fixed bed column at 30 degrees C, pH 3.5 and 4.5 for Fe(III) and Zn(II), respectively, and an average particle size of 0.180 mm. In order to minimize the diffusional resistances the influence of flow rate on the breakthrough curves at feed concentrations of 1.56 meq/L for Fe(III) and 0.844 meq/L for Zn(II) was investigated. Flow rate of the minimal resistance in the bed according to mass transfer parameter were 2.0 mL/min for iron and 8.0 mL/min for zinc ions. Freundlich and Langmuir isotherm models have been used to represent the column equilibrium data. The iron dynamic isotherm was successfully modeled by the Langmuir equation and this mathematical model described well the experimental breakthrough curves for feed concentrations from 0.1 up to 3.5 meq/L. The zinc dynamic isotherm was successfully modeled by the Freundlich equation. This equilibrium model was applied to mathematical model. Experimental breakthrough curves could be predicted. Experiments were also carried out in a batch reactor to investigate the kinetics adsorption of the ions Fe(III) and Zn(II). Langmuir kinetic model fit well both experimental data.

  20. Spectroelectrochemistry of Fe(III)- and Co(III)-mimochrome VI artificial enzymes immobilized on mesoporous ITO electrodes.

    Science.gov (United States)

    Vitale, R; Lista, L; Lau-Truong, S; Tucker, R T; Brett, M J; Limoges, B; Pavone, V; Lombardi, A; Balland, V

    2014-02-21

    UV-visible absorption spectroelectrochemistry elucidated the different redox behaviours of Fe(III)- and Co(III)-mimochrome VI artificial enzymes, adsorbed on mesoporous conductive films of ITO. The reduction of the ferric complex was rapid and reversible, while the cobaltic complex exhibited irreversible processes probably related to multiple coordination states.

  1. Condutividade da Polianilina e Poliacrilonitrila Dopadas com Fe(II e Fe(III

    Directory of Open Access Journals (Sweden)

    Yonis Fornazier Filho

    2015-01-01

    Full Text Available In this work we report O estudo da interação de íons Fe(II com a polianilina foi feito através da obtenção deste polímero na forma de salthe studies on Polyaniline Emeraldine (PANI-ES and Polyacrilonitrile (PAN doped with salt of Fe (II and Fe(III. We used the techniques of conductivity measurements with aplicação de pressão.application of pressure.  The results showed that conductivity of PANI-ES increase with pressure of range of 1.73 MPa until 20.0 MPa and PAN also increase with maximum of 6.0 mPa except to samples PAN-2-TT-FeIII and PAN-2-TTAA-FeIII.

  2. Magnetic properties of weakly exchange-coupled high spin Co(II) ions in pseudooctahedral coordination evaluated by single crystal X-band EPR spectroscopy and magnetic measurements.

    Science.gov (United States)

    Neuman, Nicolás I; Winkler, Elín; Peña, Octavio; Passeggi, Mario C G; Rizzi, Alberto C; Brondino, Carlos D

    2014-03-01

    We report single-crystal X-band EPR and magnetic measurements of the coordination polymer catena-(trans-(μ2-fumarato)tetraaquacobalt(II)), 1, and the Co(II)-doped Zn(II) analogue, 2, in different Zn:Co ratios. 1 presents two magnetically inequivalent high spin S = 3/2 Co(II) ions per unit cell, named A and B, in a distorted octahedral environment coordinated to four water oxygen atoms and trans coordinated to two carboxylic oxygen atoms from the fumarate anions, in which the Co(II) ions are linked by hydrogen bonds and fumarate molecules. Magnetic susceptibility and magnetization measurements of 1 indicate weak antiferromagnetic exchange interactions between the S = 3/2 spins of the Co(II) ions in the crystal lattice. Oriented single crystal EPR experiments of 1 and 2 were used to evaluate the molecular g-tensor and the different exchange coupling constants between the Co(II) ions, assuming an effective spin S′= 1/2. Unexpectedly, the eigenvectors of the molecular g-tensor were not lying along any preferential bond direction, indicating that, in high spin Co(II) ions in roughly octahedral geometry with approximately axial EPR signals, the presence of molecular pseudo axes in the metal site does not determine preferential directions for the molecular g-tensor. The EPR experiment and magnetic measurements, together with a theoretical analysis relating the coupling constants obtained from both techniques, allowed us to evaluate selectively the exchange coupling constant associated with hydrogen bonds that connect magnetically inequivalent Co(II) ions (|JAB(1/2)| = 0.055(2) cm(–1)) and the exchange coupling constant associated with a fumarate bridge connecting equivalent Co(II) ions (|JAA(1/2)| ≈ 0.25 (1) cm(–1)), in good agreement with the average J(3/2) value determined from magnetic measurements.

  3. Mechanisms of Sb(III) Photooxidation by the Excitation of Organic Fe(III) Complexes.

    Science.gov (United States)

    Kong, Linghao; He, Mengchang

    2016-07-05

    Organic Fe(III) complexes are widely distributed in the aqueous environment, which can efficiently generate free radicals under light illumination, playing a significant role in heavy metal speciation. However, the potential importance of the photooxidation of Sb(III) by organic Fe(III) complexes remains unclear. Therefore, the photooxidation mechanisms of Sb(III) were comprehensively investigated in Fe(III)-oxalate, Fe(III)-citrate and Fe(III)-fulvic acid (FA) solutions by kinetic measurements and modeling. Rapid photooxidation of Sb(III) was observed in an Fe(III)-oxalate solution over the pH range of 3 to 7. The addition of tert-butyl alcohol (TBA) as an ·OH scavenger quenched the Sb(III) oxidation, suggesting that ·OH is an important oxidant for Sb(III). However, the incomplete quenching of Sb(III) oxidation indicated the existence of other oxidants, presumably an Fe(IV) species in irradiated Fe(III)-oxalate solution. In acidic solutions, ·OH may be formed by the reaction of Fe(II)(C2O4) with H2O2, but a hypothetical Fe(IV) species may be generated by the reaction of Fe(II)(C2O4)2(2-) with H2O2 at higher pH. Kinetic modeling provides a quantitative explanation of the results. Evidence for the existence of ·OH and hypothetical Fe(IV) was also observed in an irradiated Fe(III)-citrate and Fe(III)-FA system. This study demonstrated an important pathway of Sb(III) oxidation in surface waters.

  4. Geochemical control of microbial Fe(III) reduction potential in wetlands: Comparison of the rhizosphere to non-rhizosphere soil

    Science.gov (United States)

    Weiss, J.V.; Emerson, D.; Megonigal, J.P.

    2004-01-01

    We compared the reactivity and microbial reduction potential of Fe(III) minerals in the rhizosphere and non-rhizosphere soil to test the hypothesis that rapid Fe(III) reduction rates in wetland soils are explained by rhizosphere processes. The rhizosphere was defined as the area immediately adjacent to a root encrusted with Fe(III)-oxides or Fe plaque, and non-rhizosphere soil was 0.5 cm from the root surface. The rhizosphere had a significantly higher percentage of poorly crystalline Fe (66??7%) than non-rhizosphere soil (23??7%); conversely, non-rhizosphere soil had a significantly higher proportion of crystalline Fe (50??7%) than the rhizosphere (18??7%, Psoil Fe(III)-oxide pool. Similarly, microbial reduction consumed 75-80% of the rhizosphere pool in 10 days compared to 30-40% of the non-rhizosphere soil pool. Differences between the two pools persisted when samples were amended with an electron-shuttling compound (AQDS), an Fe(III)-reducing bacterium (Geobacter metallireducens), and organic carbon. Thus, Fe(III)-oxide mineralogy contributed strongly to differences in the Fe(III) reduction potential of the two pools. Higher amounts of poorly crystalline Fe(III) and possibly humic substances, and a higher Fe(III) reduction potential in the rhizosphere compared to the non-rhizosphere soil, suggested the rhizosphere is a site of unusually active microbial Fe cycling. The results were consistent with previous speculation that rapid Fe cycling in wetlands is due to the activity of wetland plant roots. ?? 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.

  5. The adsorption properties of Pb(II) and Cd(II) on functionalized graphene prepared by electrolysis method

    Energy Technology Data Exchange (ETDEWEB)

    Deng Xiaojiao; Lue Lili; Li Hongwei [Key Laboratory of Polyoxometalates Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024 (China); Luo Fang, E-mail: luof746@nenu.edu.cn [Key Laboratory of Polyoxometalates Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2010-11-15

    The functionalized graphene (GNS{sup PF6}) was fabricated by simple and fast method of electrolysis with potassium hexafluorophosphate solution as electrolyte under the static potential of 15 V. The characterization results of transmission electron microscopy, atom force microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, Raman spectroscopy and thermogravimetric analysis indicate that graphite rod was completely exfoliated to graphene layer containing 30 wt.% PF{sub 6}{sup -} with the average thickness ca. 1.0 nm. Our sample of GNS{sup PF6} was developed for the removal of Pb(II) or Cd(II) ions from water, and the determined adsorption capacities are 406.6 mg/g (pH = 5.1) for Pb(II) and 73.42 mg/g (pH = 6.2) for Cd(II), which is much higher than that by our previous sample of GNS{sup C8P} and carbon nanotube. The adsorption processes reach equilibrium in just 40 min and the adsorption isotherms are described well by Langmuir and Freundlich classical isotherms models.

  6. The adsorption properties of Pb(II) and Cd(II) on functionalized graphene prepared by electrolysis method.

    Science.gov (United States)

    Deng, Xiaojiao; Lü, Lili; Li, Hongwei; Luo, Fang

    2010-11-15

    The functionalized graphene (GNS(PF6)) was fabricated by simple and fast method of electrolysis with potassium hexafluorophosphate solution as electrolyte under the static potential of 15 V. The characterization results of transmission electron microscopy, atom force microscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, Raman spectroscopy and thermogravimetric analysis indicate that graphite rod was completely exfoliated to graphene layer containing 30 wt.% PF(6)- with the average thickness ca. 1.0 nm. Our sample of GNS(PF6) was developed for the removal of Pb(II) or Cd(II) ions from water, and the determined adsorption capacities are 406.6 mg/g (pH=5.1) for Pb(II) and 73.42 mg/g (pH=6.2) for Cd(II), which is much higher than that by our previous sample of GNS(C8P) and carbon nanotube. The adsorption processes reach equilibrium in just 40 min and the adsorption isotherms are described well by Langmuir and Freundlich classical isotherms models.

  7. An Optical Biosensor from Green Fluorescent Escherichia coli for the Evaluation of Single and Combined Heavy Metal Toxicities

    Directory of Open Access Journals (Sweden)

    Dedi Futra

    2015-05-01

    Full Text Available A fluorescence-based fiber optic toxicity biosensor based on genetically modified Escherichia coli (E. coli with green fluorescent protein (GFP was developed for the evaluation of the toxicity of several hazardous heavy metal ions. The toxic metals include Cu(II, Cd(II, Pb(II, Zn(II, Cr(VI, Co(II, Ni(II, Ag(I and Fe(III. The optimum fluorescence excitation and emission wavelengths of the optical biosensor were 400 ± 2 nm and 485 ± 2 nm, respectively. Based on the toxicity observed under optimal conditions, the detection limits of Cu(II, Cd(II, Pb(II, Zn(II, Cr(VI, Co(II, Ni(II, Ag(I and Fe(III that can be detected using the toxicity biosensor were at 0.04, 0.32, 0.46, 2.80, 100, 250, 400, 720 and 2600 μg/L, respectively. The repeatability and reproducibility of the proposed biosensor were 3.5%–4.8% RSD (relative standard deviation and 3.6%–5.1% RSD (n = 8, respectively. The biosensor response was stable for at least five weeks, and demonstrated higher sensitivity towards metal toxicity evaluation when compared to a conventional Microtox assay.

  8. A double network gel as low cost and easy recycle adsorbent: Highly efficient removal of Cd(II) and Pb(II) pollutants from wastewater.

    Science.gov (United States)

    Chu, Lin; Liu, Chengbin; Zhou, Guiyin; Xu, Rui; Tang, Yanhong; Zeng, Zebing; Luo, Shenglian

    2015-12-30

    A high strength of polyving alcohol/polyacrylic acid double network gel (PVA/PAA gel) adsorbent was successfully prepared by a simple two-step method in this study. The gel adsorbent possessed the advantages of low cost and high adsorptivity for heavy metals in solution. The maximum uptake capacities of PVA/PAA gel were 194.99 mg/g for Pb(II) and 115.88 mg/g for Cd(II) inferred from the Langmuir model at 303 K. At the concentration levels of Pb(II)<150 mg/L and Cd(II)<100mg/L, the Pb(II) and Cd(II) could be completely adsorbed, showing a great potential of removing heavy metals from wastewater. Simultaneously, the PVA/PAA gel adsorbent exhibited an excellent reusability. Even in the fifth cycle, the removal efficiencies of both Pb(II) and Cd(II) remained nearly 100%. Significantly, the gel adsorbent displayed a satisfactory performance of removing heavy metals in actual industrial effluent. The results reveal that the double network gel can be considered as a potential candidate for practical application.

  9. Heavy metal/polyacid interaction. An electrochemical study of the binding of Cd(II), Pb(II) and Zn(II) to polycarboxylic and humic acids

    NARCIS (Netherlands)

    Cleven, R.F.M.J.

    1984-01-01

    Polyelectrolyte effects in the interaction of heavy metal ions with model polycarboxylic acids have been described, in order to establish the relevance of these effects in the interaction of heavy metal ions with naturally occurring humic and fulvic acids. The model systems consisted of Cd(II), Pb(I

  10. Towards the role of metal ions in the structural variability of proteins: CdII speciation of a metal ion binding loop motif

    DEFF Research Database (Denmark)

    Jancsó, Attila; Szunyogh, Dániel; Gyurcsik, Béla;

    2011-01-01

    on their structure and dynamics. The interaction with CdII was investigated by UV, synchrotron radiation CD, 1H NMR, and perturbed angular correlation (PAC) of γ-rays spectroscopy, pH-potentiometry, and molecular modelling. The peptide mainly displays characteristics of random coil in the CD spectra...

  11. Cooperative cathode electrode and in situ deposited copper for subsequent enhanced Cd(II) removal and hydrogen evolution in bioelectrochemical systems.

    Science.gov (United States)

    Wang, Qiang; Huang, Liping; Pan, Yuzhen; Zhou, Peng; Quan, Xie; Logan, Bruce E; Chen, Hongbo

    2016-01-01

    Bioelectrochemical systems (BESs) were first operated in microbial fuel cell mode for recovering Cu(II), and then shifted to microbial electrolysis cells for Cd(II) reduction on the same cathodes of titanium sheet (TS), nickel foam (NF) or carbon cloth (CC). Cu(II) reduction was similar to all materials (4.79-4.88mg/Lh) whereas CC exhibited the best Cd(II) reduction (5.86±0.25mg/Lh) and hydrogen evolution (0.35±0.07m(3)/m(3)d), followed by TS (5.27±0.43mg/Lh and 0.15±0.02m(3)/m(3)d) and NF (4.96±0.48mg/Lh and 0.80±0.07m(3)/m(3)d). These values were higher than no copper controls by factors of 2.0 and 5.0 (TS), 4.2 and 2.0 (NF), and 1.8 and 7.0 (CC). These results demonstrated cooperative cathode electrode and in situ deposited copper for subsequent enhanced Cd(II) reduction and hydrogen production in BESs, providing an alternative approach for efficiently remediating Cu(II) and Cd(II) co-contamination with simultaneous hydrogen production.

  12. Column dynamic studies and breakthrough curve analysis for Cd(II) and Cu(II) ions adsorption onto palm oil boiler mill fly ash (POFA).

    Science.gov (United States)

    Aziz, Abdul Shukor Abdul; Manaf, Latifah Abd; Man, Hasfalina Che; Kumar, Nadavala Siva

    2014-01-01

    This paper investigates the adsorption characteristics of palm oil boiler mill fly ash (POFA) derived from an agricultural waste material in removing Cd(II) and Cu(II) from aqueous solution via column studies. The performance of the study is described through the breakthrough curves concept under relevant operating conditions such as column bed depths (1, 1.5, and 2 cm) and influent metal concentrations (5, 10, and 20 mg/L). The Cd(II) and Cu(II) uptake mechanism is particularly bed depth- and concentration-dependant, favoring higher bed depth and lower influent metal concentration. The highest bed capacity of 34.91 mg Cd(II)/g and 21.93 mg Cu(II)/g of POFA was achieved at 20 mg/L of influent metal concentrations, column bed depth of 2 cm, and flow rate of 5 mL/min. The whole breakthrough curve simulation for both metal ions were best described using the Thomas and Yoon–Nelson models, but it is apparent that the initial region of the breakthrough for Cd(II) was better described using the BDST model. The results illustrate that POFA could be utilized effectively for the removal of Cd(II) and Cu(II) ions from aqueous solution in a fixed-bed column system.

  13. Structural, DFT and biological studies on Co(II) complexes of semi and thiosemicarbazide ligands derived from diketo hydrazide

    Science.gov (United States)

    Yousef, T. A.; El-Gammal, O. A.; Ahmed, Sara F.; Abu El-Reash, G. M.

    2014-11-01

    Three ligands have been prepared by addition ethanolic suspension of 2-hydrazino-2-oxo-N-phenyl-acetamide to phenyl isocyanate (H2PAPS), phenyl isothiocyanate (H2PAPT) and benzoyl isothiocyanate (H2PABT). The Co(II) chloride complexes were prepared and characterized by conventional techniques. The isolated complexes were assigned the formulaes, [Co(HPAPS)Cl(H2O)2]H2O, [Co(HPAPT)Cl]H2O and [Co(H2PABT)Cl2], respectively. The IR spectra of complexes shows that H2PAPS behaves as a mononegative tridentate via CO of hydrazide moiety and enolized CO of hydrazide moiety and CN (azomethine) group due to enolization of CO isocyanate moiety. H2PAPT behaves as mononegative tridentate via one CO of hydrazide moiety and thiol CS and NH groups and finally H2PABT behaves as neutral tetradentate via one CO of hydrazide moiety, CO of benzoyl moiety, Cdbnd S due to enolization of the second CO of hydrazide moiety and new CN (azomethine) groups. The vibrational frequencies of the IR spectra of ligands which were determined experimentally are compared with those obtained theoretically from DFT calculations. Also, the bond lengths, bond angles, HOMO, LUMO and dipole moments have been calculated. The calculated HOMO-LUMO energy gap reveals that charge transfer occurs within the ligand molecules. The calculated values of binding energies indicates the stability of metal complexes is higher that of ligand. Also, the kinetic and thermodynamic parameters for the different thermal degradation steps of the complexes were determined by Coats-Redfern and Horowitz-Metzger methods. The antibacterial activities were also tested against Bacillus subtilis and Escherichia coli bacteria. The free ligands showed a higher antibacterial effect than their Co(II) complexes except [Co(HPAPS)Cl(H2O)2]H2O which shows higher activity than corresponding ligand. The antitumor activities of the Ligands and their Co(II) complexes have been evaluated against liver (HePG2) and breast (MCF-7) cancer cells. All ligands

  14. Kinetics and Thermodynamics of Cd(II Ions Sorption on Mixed Sorbents Prepared from Olive Stone and Date Pit from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    N. Babakhouya

    2010-01-01

    Full Text Available Problem statement: The aim of this study is to remove Cd(II ions from aqueous solutions by adsorption. Mixed sorbent prepared from olive stone and date pit, an agricultural solid by-product was used as adsorbent. Approach: The adsorption experiments of Cd(II onto the mixture of olive stone and date pit were conducted at different parameters such as, percent of olive stone and date pit in the mixture, temperature, initial solution pH and initial Cd(II concentration. Adsorption isotherms were obtained at different percent of olive stone and date pit in the mixture. Results: This adsorption data was fitted with the Langmuir. Kinetic studies revealed that the initial uptake was rapid and equilibrium was established in 20 min for all the studied metals and that the data followed the pseudo-second order reaction. The thermodynamic of Cadmium sorption on the mixed sorbent follows the Langmuir model and the sorption capacity for cadmium increases when we add a small amount of olive stone at date pits (90% of date pits in mixture and 10% of olive stone and a small amount of date pits at olive stone (90% of olive stone and 10% of date pits in mixture. In addition, the thermodynamic parameters, standard free energy (ÄG°, standard enthalpy (ÄH° and standard entropy (ÄS° of the adsorption process were calculated. The sorption of Cd(II onto the mixture of olive stones and dates pit is spontaneous and presents an endothermic nature. The characteristics of the mixture were determined by the analysis of infra red spectral analysis. Conclusion: The results show that the mixture sorbent from olive stone and date pit is an alternative low-cost adsorbent for removing Cd(II.

  15. Transport, fate, and stimulating impact of silver nanoparticles on the removal of Cd(II) by Phanerochaete chrysosporium in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zuo, Yanan [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Chen, Guiqiu, E-mail: gqchen@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Zeng, Guangming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Li, Zhongwu; Yan, Ming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Chen, Anwei [College of Resources and Environment, Hunan Agricultural University, Changsha 410128 (China); Guo, Zhi; Huang, Zhenzhen; Tan, Qiong [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

    2015-03-21

    Highlights: • Appropriate concentration of AgNPs can stimulate the biological removal of Cd(II). • Added AgNPs were oxidatively dissolved and transported to the surface of fungus. • AgNPs have undergone coarsening in the process of transport. • Amino, carboxyl, hydroxyl, and other reducing groups were involved in transportion. - Abstract: Despite the knowledge about increasing discharge of silver nanoparticles (AgNPs) into wastewater and its potential toxicity to microorganisms, the interaction of AgNPs with heavy metals in the biological removal process remains poorly understood. This study focused on the effect of AgNPs (hydrodynamic diameter about 24.3 ± 0.37 nm) on the removal of cadmium (Cd(II)) by using a model white rot fungus species, Phanerochaete chrysosporium. Results showed that the biological removal capacity of Cd(II) increased with the concentration of AgNPs increasing from 0.1 mg/L to 1 mg/L. The maximum removal capacity (4.67 mg/g) was located at 1 mg/L AgNPs, and then decreased with further increasing AgNPs concentration, suggesting that an appropriate concentration of AgNPs has a stimulating effect on the removal of Cd(II) by P. chrysosporium instead of an inhibitory effect. Results of Ag{sup +} and total Ag concentrations in the solutions together with those of SEM and XRD demonstrated that added AgNPs had undergone oxidative dissolution and transported from the solution to the surface of fungal mycelia (up to 94%). FTIR spectra confirmed that amino, carboxyl, hydroxyl, and other reducing functional groups were involved in Cd(II) removal, AgNPs transportation, and the reduction of Ag{sup +} to AgNPs.

  16. Optimization of Stripping Voltammetric Sensor by a Back Propagation Artificial Neural Network for the Accurate Determination of Pb(II) in the Presence of Cd(II).

    Science.gov (United States)

    Zhao, Guo; Wang, Hui; Liu, Gang; Wang, Zhiqiang

    2016-09-21

    An easy, but effective, method has been proposed to detect and quantify the Pb(II) in the presence of Cd(II) based on a Bi/glassy carbon electrode (Bi/GCE) with the combination of a back propagation artificial neural network (BP-ANN) and square wave anodic stripping voltammetry (SWASV) without further electrode modification. The effects of Cd(II) in different concentrations on stripping responses of Pb(II) was studied. The results indicate that the presence of Cd(II) will reduce the prediction precision of a direct calibration model. Therefore, a two-input and one-output BP-ANN was built for the optimization of a stripping voltammetric sensor, which considering the combined effects of Cd(II) and Pb(II) on the SWASV detection of Pb(II) and establishing the nonlinear relationship between the stripping peak currents of Pb(II) and Cd(II) and the concentration of Pb(II). The key parameters of the BP-ANN and the factors affecting the SWASV detection of Pb(II) were optimized. The prediction performance of direct calibration model and BP-ANN model were tested with regard to the mean absolute error (MAE), root mean square error (RMSE), average relative error (ARE), and correlation coefficient. The results proved that the BP-ANN model exhibited higher prediction accuracy than the direct calibration model. Finally, a real samples analysis was performed to determine trace Pb(II) in some soil specimens with satisfactory results.

  17. Kinetic and thermodynamic studies of the Co(II) and Ni(II) ions removal from aqueous solutions by Ca-Mg phosphates.

    Science.gov (United States)

    Ivanets, A I; Srivastava, V; Kitikova, N V; Shashkova, I L; Sillanpää, M

    2017-03-01

    The aim of this work was to study the sorption kinetics and thermodynamics of Co(II) and Ni(II) from aqueous solutions by sorbents on the basis of hydrogen (PD-1) and tertiary (PD-2) Ca-Mg phosphates depending on the solution temperature and sorbents chemical composition. Kinetic studies of adsorption of Co(II) and Ni(II) ions onto samples of phosphate sorbents were performed in batch experiment at the temperatures 288, 303, 318 and 333 K. The sorbent dose was fixed at 10 g L(-1), initial pH value 2.6, and contact time varied from 5 to 600 min. The kinetics of Co(II) and Ni(II) adsorption were analyzed by using pseudo-first order, pseudo-second order and intraparticle diffusion models. Thermodynamic parameters (ΔG°, ΔH° and ΔS°) for the sorption of Co(II) and Ni(II) were determined using the Gibbs-Helmholtz equation. The calculated kinetic parameters and corresponding correlation coefficients revealed that Co(II) and Ni(II) uptake process followed the pseudo-second order rate expression. Thermodynamic studies confirmed the spontaneous and endothermic nature of removal process which indicate that sorption of Co(II) and Ni(II) ions onto both phosphate sorbents is favoured at higher temperatures and has the chemisorptive mechanism. The data thus obtained would be useful for practical application of the low cost and highly effective Ca-Mg phosphate sorbents.

  18. Synthesis and characterization of mixed ligand complexes of Zn(II) and Co(II) with amino acids: Relevance to zinc binding sites in zinc fingers

    Indian Academy of Sciences (India)

    P Rabindra Reddy; M Radhika; P Manjula

    2005-05-01

    Mixed ligand complexes of Zn(II) and Co(II) with cysteine, histidine, cysteinemethylester, and histidinemethylester have been synthesized and characterized by elemental analysis, conductivity, magnetic susceptibility measurements, and infrared, 1H NMR, TGA and FAB mass spectra. In these complexes, histidine, and histidinemethylester act as bidentate ligands involving amino and imidazole nitrogens in metal coordination. Similarly, cysteine, and cysteinemethylester also act as bidentate ligands coordinating through thiol sulphur and amino nitrogen. Tetrahedral geometry has been proposed for Zn(II) and Co(II) complexes based on experimental evidence.

  19. Single-ion-magnet behavior in a two-dimensional coordination polymer constructed from Co(II) nodes and a pyridylhydrazone derivative.

    Science.gov (United States)

    Liu, Xiangyu; Sun, Lin; Zhou, Huiliang; Cen, Peipei; Jin, Xiaoyong; Xie, Gang; Chen, Sanping; Hu, Qilin

    2015-09-21

    A novel two-dimensional (2D) coordination polymer, [Co(ppad)2]n (1), resulted from the assembly of Co(II) ions based on a versatile ligand termed N(3)-(3-pyridoyl)-3-pyridinecarboxamidrazone. Alternating/direct-current magnetic studies of compound 1 indicate that the spatially separated high-spin Co(II) ions act as single-ion magnets (SIMs). The present work represents the first case of a 2D Co(II)-based SIM composed of a monocomponent organic spacer.

  20. In situ tetrazole templated chair-like decanuclear azido-cobalt(II) SMM containing both tetra- and octa-hedral Co(II) ions.

    Science.gov (United States)

    Zhang, Yuan-Zhu; Gao, Song; Sato, Osamu

    2015-01-14

    An azido-bridged chair-like decanuclear cluster: [Co(II)10(bzp)8(Metz)2(N3)18]·4MeOH·3H2O (1, bzp = 2-benzoylpyridine and HMetz = 5-methyl-1H-tetrazole) was prepared with in situ tetrazolate anions as templates in a sealed system. 1 containing both octahedral and tetrahedral Co(II) ions exhibited slow relaxation of magnetization with an effective barrier of 26 K under an applied dc field of 1 kOe.

  1. Potentiometric Polymeric Film Sensors Based on 5,10,15-tris(4-aminophenyl Porphyrinates of Co(II and Cu(II for Analysis of Biological Liquids

    Directory of Open Access Journals (Sweden)

    Larisa Lvova

    2011-01-01

    Full Text Available Novel carbonate-selective potentiometric sensors based on 5,10,15-tris(4-aminophenyl-20-phenyl porphyrinates of Cu(II and Co(II have been developed. Ionophore functioning mechanism and possible source of carbonate sensitivity have been evolved. Potentiometric properties of Co(II- and Cu(IITATPP-based sensors were compared with common carbonate-ISEs containing trifluoroacetophenone derivatives. The analytical utility of newly developed sensors has been demonstrated by measuring the bicarbonate content in human blood plasma.

  2. Evaluation of siderite and magnetite formation in BIFs by pressure-temperature experiments of Fe(III) minerals and microbial biomass

    Science.gov (United States)

    Halama, Maximilian; Swanner, Elizabeth D.; Konhauser, Kurt O.; Kappler, Andreas

    2016-09-01

    Anoxygenic phototrophic Fe(II)-oxidizing bacteria potentially contributed to the deposition of Archean banded iron formations (BIFs), before the evolution of cyanobacterially-generated molecular oxygen (O2), by using sunlight to oxidize aqueous Fe(II) and precipitate Fe(III) (oxyhydr)oxides. Once deposited at the seafloor, diagenetic reduction of the Fe(III) (oxyhydr)oxides by heterotrophic bacteria produced secondary Fe(II)-bearing minerals, such as siderite (FeCO3) and magnetite (Fe3O4), via the oxidation of microbial organic carbon (i.e., cellular biomass). During deeper burial at temperatures above the threshold for life, thermochemical Fe(III) reduction has the potential to form BIF-like minerals. However, the role of thermochemical Fe(III) reduction of primary BIF minerals during metamorphism, and its impact on mineralogy and geochemical signatures in BIFs, is poorly understood. Consequently, we simulated the metamorphism of the precursor and diagenetic iron-rich minerals (ferrihydrite, goethite, hematite) at low-grade metamorphic conditions (170 °C, 1.2 kbar) for 14 days by using (1) mixtures of abiotically synthesized Fe(III) minerals and either microbial biomass or glucose as a proxy for biomass, and (2) using biogenic minerals formed by phototrophic Fe(II)-oxidizing bacteria. Mössbauer spectroscopy and μXRD showed that thermochemical magnetite formation was limited to samples containing ferrihydrite and glucose, or goethite and glucose. No magnetite was formed from Fe(III) minerals when microbial biomass was present as the carbon and electron sources for thermochemical Fe(III) reduction. This could be due to biomass-derived organic molecules binding to the mineral surfaces and preventing solid-state conversion to magnetite. Mössbauer spectroscopy revealed siderite contents of up to 17% after only 14 days of incubation at elevated temperature and pressure for all samples with synthetic Fe(III) minerals and biomass, whereas 6% of the initial Fe(III) was

  3. Biochar-Facilitated Reduction of Crystalline Fe(III) in Hematite

    Science.gov (United States)

    Xu, S.; Yang, Y.; Roden, E. E.; Tang, Y.; Huang, R.; Adhikari, D.

    2015-12-01

    Pyrogenic organic matter is a significant component of soil organic matter, the transformation of which may play a crucial role in the coupled redox cycles of carbon and iron. However, scant information is available for the role of pyrogenic carbon in the redox cycle of iron. Herein, we studied the influences of wheat straw-derived biochar on the microbial reduction of hematite by Shewanella oneidensis MR-1. In the presence of 10 mg/L biochar, microbial reduction of hematite was substantially accelerated by 41% to 142%. Reduction of hematite was enhanced to similar degrees by aqueous biochar with the concentration of 1-3 mg C/L. Importance of the aqueous biochar was also supported by the response of enhancement of Fe reduction to the dose of biochar particles, closely linked to the change in aqueous biochar concentration rather than the amount of total biochar particles. Microbiologically pre-reduced biochar reduced hematite abiotically, demonstrating the electron shuttling capacity of aqueous biochar for hematite reduction. On the other side, biochar particles sorbed Fe(II) and consequently decreased the accumulation of Fe(II) in solution to facilitate the reduction of hematite further. We reported for the first time the biochar-facilitated microbial reduction of crystalline Fe(III), through electron shuttling processes mediated by aqueous biochar and complexation of Fe(II) by biochar particles. Such impacted redox cycles of Fe would be important for the soil environment with relatively high content of indigenous pyrogenic carbon or substantial application of biochar.

  4. Equilibrium, thermoanalytical and spectroscopic studies to characterize phytic acid complexes with Mn(II) and Co(II)

    Energy Technology Data Exchange (ETDEWEB)

    Carli, Ligia de; Schnitzler, Egon; Rosso, Neiva Deliberali [Universidade Estadual de Ponta Grossa (UEPG), PR (Brazil). Dept. de Quimica], e-mail: ndrosso@uepg.br; Ionashiro, Massao [Universidade Estadual Paulista (UNESP), Araraquara, SP (Brazil). Inst. de Quimica; Szpoganicz, Bruno [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Quimica

    2009-07-01

    Potentiometric studies were carried out to determine the binding degree of phytic acid with Co(II) and Mn(II) ions, in the absence of dioxygen. Equilibrium constants for all major complexes formed are reported, and the results are presented in the form of distribution diagrams showing the concentrations of individual complexes as a function of pH. The formation constants of the complexes show higher values for the species in which the ligand was more deprotonated. Potentiometric data indicates that the species [MH{sub 4}L]{sup 6-}, was totally formed at pH 7.0 and the complexes were synthesized from this data. A solid state complex of Mn(II) and Co(II) with phytic acid was synthesized. Thermogravimetry, differential scanning calorimetry, and infrared spectroscopy were used to investigate and characterize the thermal behavior of these compounds. The results led to information on the composition, dehydration, thermal stability and thermal decomposition of the isolated complexes. (author)

  5. ADSORPTION CHARACTERIZATION OF CO(II IONS ONTO CHEMICALLY TREATED QUERCUS COCCIFERA SHELL: EQUILIBRIUM, KINETIC AND THERMODYNAMIC STUDIES

    Directory of Open Access Journals (Sweden)

    M. Hamdi Karaoglu

    2011-04-01

    Full Text Available Quercus coccifera shell (QCS, a relatively abundant and inexpensive material, is currently being investigated as an adsorbent to remove cobalt(II from water. Before the adsorption experiments, QCS was subjected to chemical treatment to provide maximum surface area. Then, the kinetics and adsorption mechanism of Co(II ions on QCS were studied using different parameters such as adsorbent dosage, initial concentration, temperature, contact time, and solution pH. The loaded metals could be desorbed effectively with dilute hydrochloric acid, nitric acid, and 0.1 M EDTA. The Langmuir and Freundlich models were used to describe the uptake of cobalt on QCS. The equilibrium adsorption data were better fitted to Langmuir adsorption isotherm model. The maximum adsorption capacity (qm of QCS for Co(II was 33 mg g-1. Various kinetic models were used to describe the adsorption process. The adsorption followed pseudo second-order kinetic model. The intraparticle diffusion was found to be the rate-limiting step in the adsorption process. The diffusion coefficients were calculated and found to be in the range of 3.11×10−6 to 168.78×10−6 cm2s-1. The negative DH* value indicated exothermic nature of the adsorption.

  6. A simple small size and low cost sensor based on surface plasmon resonance for selective detection of Fe(III).

    Science.gov (United States)

    Cennamo, Nunzio; Alberti, Giancarla; Pesavento, Maria; D'Agostino, Girolamo; Quattrini, Federico; Biesuz, Raffaela; Zeni, Luigi

    2014-03-07

    A simple, small size, and low cost sensor based on a Deferoxamine Self Assembled Monolayer (DFO-SAM) and Surface Plasmon Resonance (SPR) transduction, in connection with a Plastic Optical Fiber (POF), has been developed for the selective detection of Fe(III). DFO-SAM sensors based on appropriate electrochemical techniques can be frequently found in the scientific literature. In this work, we present the first example of a DFO-SAM sensor based on SPR in an optical fiber. The SPR sensing platform was realized by removing the cladding of a plastic optical fiber along half the circumference, spin coating a buffer of Microposit S1813 photoresist on the exposed core, and finally sputtering a thin gold film. The hydroxamate siderophore deferoxamine (DFO), having high binding affinity for Fe(III), is then used in its immobilized form, as self-assembled monolayer on the gold layer surface of the POF sensor. The results showed that the DFO-SAM-POF-sensor was able to sense the formation of the Fe(III)/DFO complex in the range of concentrations between 1 μm and 50 μm with a linearity range from 0 to 30 μm of Fe(III). The selectivity of the sensor was also proved by interference tests.

  7. Heterogeneous reduction of PuO₂ with Fe(II): importance of the Fe(III) reaction product.

    Science.gov (United States)

    Felmy, Andrew R; Moore, Dean A; Rosso, Kevin M; Qafoku, Odeta; Rai, Dhanpat; Buck, Edgar C; Ilton, Eugene S

    2011-05-01

    Heterogeneous reduction of actinides in higher, more soluble oxidation states to lower, more insoluble oxidation states by reductants such as Fe(II) has been the subject of intensive study for more than two decades. However, Fe(II)-induced reduction of sparingly soluble Pu(IV) to the more soluble lower oxidation state Pu(III) has been much less studied, even though such reactions can potentially increase the mobility of Pu in the subsurface. Thermodynamic calculations are presented that show how differences in the free energy of various possible solid-phase Fe(III) reaction products can greatly influence aqueous Pu(III) concentrations resulting from reduction of PuO₂(am) by Fe(II). We present the first experimental evidence that reduction of PuO₂(am) to Pu(III) by Fe(II) was enhanced when the Fe(III) mineral goethite was spiked into the reaction. The effect of goethite on reduction of Pu(IV) was demonstrated by measuring the time dependence of total aqueous Pu concentration, its oxidation state, and system pe/pH. We also re-evaluated established protocols for determining Pu(III) {[Pu(III) + Pu(IV)] - Pu(IV)} by using thenoyltrifluoroacetone (TTA) in toluene extractions; the study showed that it is important to eliminate dissolved oxygen from the TTA solutions for accurate determinations. More broadly, this study highlights the importance of the Fe(III) reaction product in actinide reduction rate and extent by Fe(II).

  8. Fe(III) shifts the mitochondria permeability transition-eliciting capacity of mangiferin to protection of organelle.

    Science.gov (United States)

    Pardo-Andreu, Gilberto L; Cavalheiro, Renata A; Dorta, Daniel J; Naal, Zeki; Delgado, René; Vercesi, Aníbal E; Curti, Carlos

    2007-02-01

    Mangiferin acts as a strong antioxidant on mitochondria. However, when in the presence of Ca(2+), mangiferin elicits mitochondrial permeability transition (MPT), as evidenced by cyclosporin A-sensitive mitochondrial swelling. We now provide evidence, by means of electrochemical and UV-visible spectroscopical analysis, that Fe(III) coordinates with mangiferin. The resulting mangiferin-Fe(III) complex does not elicit MPT and prevents MPT by scavenging reactive oxygen species. Indeed, the complex protects mitochondrial membrane protein thiols and glutathione from oxidation. Fe(III) also significantly increases the ability of mangiferin to scavenge the 2,2-diphenyl-1-picrylhydrazyl radical, as well as to display antioxidant activity toward antimycin A-induced H(2)O(2) production and t-butyl hydroperoxide-promoted membrane lipid peroxidation in mitochondria. We postulate that coordination with Fe(III) constitutes a potential protective mechanism toward the prooxidant action of mangiferin and other catechol-containing antioxidants regarding MPT induction. Potential therapeutic relevance of this finding for conditions of pathological iron overload is discussed.

  9. A Simple Small Size and Low Cost Sensor Based on Surface Plasmon Resonance for Selective Detection of Fe(III

    Directory of Open Access Journals (Sweden)

    Nunzio Cennamo

    2014-03-01

    Full Text Available A simple, small size, and low cost sensor based on a Deferoxamine Self Assembled Monolayer (DFO-SAM and Surface Plasmon Resonance (SPR transduction, in connection with a Plastic Optical Fiber (POF, has been developed for the selective detection of Fe(III. DFO-SAM sensors based on appropriate electrochemical techniques can be frequently found in the scientific literature. In this work, we present the first example of a DFO-SAM sensor based on SPR in an optical fiber. The SPR sensing platform was realized by removing the cladding of a plastic optical fiber along half the circumference, spin coating a buffer of Microposit S1813 photoresist on the exposed core, and finally sputtering a thin gold film. The hydroxamate siderophore deferoxamine (DFO, having high binding affinity for Fe(III, is then used in its immobilized form, as self-assembled monolayer on the gold layer surface of the POF sensor. The results showed that the DFO-SAM-POF-sensor was able to sense the formation of the Fe(III/DFO complex in the range of concentrations between 1 μm and 50 μm with a linearity range from 0 to 30 μm of Fe(III. The selectivity of the sensor was also proved by interference tests.

  10. Removal of Cd(II) and Pb(II) from aqueous solution using dried water hyacinth as a biosorbent.

    Science.gov (United States)

    Ibrahim, Hanan S; Ammar, Nabila S; Soylak, Mustafa; Ibrahim, Medhat

    2012-10-01

    Possible usages of dried water hyacinth as biosorbent for metal ions were investigated. A model describing the plant is presented on density functional theory DFT and verified experimentally with FTIR. The model shows that water hyacinth is a mixture of cellulose and lignin. Dried shoot and root were found as good sorbent for Cd(II) and Pb(II) at optimum dosage of 5.0 g/l and pH 5.0; equilibrium time was attained within 30-60 min. The removal using root and shoot were nearly equal and reached more than 75% for Cd and more than 90% for Pb. Finally the second-order kinetics was the applicable model. Hydrogen bonds of reactive functional groups like COOH play the key role in the removal process.

  11. Molecular cloning, sequencing, and expression analysis of cDNA encoding metalloprotein II (MP II) induced by single and combined metals (Cu(II), Cd(II)) in polychaeta Perinereis aibuhitensis.

    Science.gov (United States)

    Yang, Dazuo; Zhou, Yibing; Zhao, Huan; Zhou, Xiaoxiao; Sun, Na; Wang, Bin; Yuan, Xiutang

    2012-11-01

    We amplified and analyzed the complete cDNA of metalloprotein II (MP II) from the somatic muscle of the polychaete Perinereis aibuhitensis, the full length cDNA is 904 bp encoding 119 amino acids. The MP II cDNA sequence was subjected to BLAST searching in NCBI and was found to share high homology with hemerythrin of other worms. MP II expression of P. aibuhitensis exposed to single and combined metals (Cu(II), Cd(II)) was analyzed using real time-PCR. MP II mRNA expression increased at the start of Cu(II) exposure, then decreased and finally return to the normal level. Expression pattern of MP II under Cd(II) exposure was time- and dose-dependent. MP II expression induced by a combination of Cd(II) and Cu(II) was similar to that induced by Cd(II) alone.

  12. A novel three-dimensional CdII metal-organic framework based on [Cd6(malonate)6] metallomacrocycles with zeolite SOD (sodalite) topology: poly[ammine-μ3-malonato-cadmium(II)].

    Science.gov (United States)

    Yuan, Shuai; Liu, Mei-Jiao; Xie, Han-Yi; Xu, Meng-Zhen; Sun, Di

    2012-03-01

    A novel Cd(II) metal-organic framework, [Cd(C(3)H(2)O(4))(NH(3))](n), was synthesized by liquid diffusion conducted in the presence of ammonia. The Cd(II) atom has seven-coordinate O(6)N pentagonal-bipyramidal geometry. Six Cd(II) centers are joined by six malonate ligands to form an S(6)-symmetric [Cd(6)(malonate)(6)] metallomacrocycle, which is further extended through a side-on chelating malonate ligand to form a three-dimensional network. Topologically, each Cd(II) center is connected to four others to yield an infinite three-periodic four-coordinated SOD (sodalite) network with point symbol {4(2)·6(4)}. The overall network structure in the crystal is maintained and stabilized by the presence of N-H...O hydrogen bonds.

  13. Equilibrium and kinetic studies of Pb(II, Cd(II and Zn(II sorption by Lagenaria vulgaris shell

    Directory of Open Access Journals (Sweden)

    Mitić-Stojanović Dragana-Linda

    2012-01-01

    Full Text Available The sorption of lead, cadmium and zinc ions from aqueous solution by Lagenaria vulgaris shell biosorbent (LVB in batch system was investigated. The effect of relevant parameters such as contact time, biosorbent dosage and initial metal ions concentration was evaluated. The Pb(II, Cd(II and Zn(II sorption equilibrium (when 98% of initial metal ions were sorbed was attained within 15, 20 and 25 min, respectively. The pseudo first, pseudo-second order, Chrastil’s and intra-particle diffusion models were used to describe the kinetic data. The experimental data fitted the pseudo-second order kinetic model and intra-particle diffusion model. Removal efficiency of lead(II, cadmium(II and zinc(II ions rapidly increased with increasing biosorbent dose from 0.5 to 8.0 g dm-3. Optimal biosorbent dose was set to 4.0 g dm-3. An increase in the initial metal concentration increases the sorption capacity. The sorption data of investigated metal ions are fitted to Langmuir, Freundlich and Temkin isotherm models. Langmuir model best fitted the equilibrium data (r2 > 0.99. Maximal sorption capacities of LVB for Pb(II, Cd(II and Zn(II at 25.0±0.5°C were 0.130, 0.103 and 0.098 mM g-1, respectively. The desorption experiments showed that the LVB could be reused for six cycles with a minimum loss of the initial sorption capacity.

  14. Selective chelation of Cd(II) and Pb(II) versus Ca(II) and Zn(II) by using octadentate ligands containing pyridinecarboxylate and pyridyl pendants.

    Science.gov (United States)

    Ferreirós-Martínez, Raquel; Esteban-Gómez, David; Platas-Iglesias, Carlos; de Blas, Andrés; Rodríguez-Blas, Teresa

    2009-12-07

    Herein we report the coordination properties toward Cd(II), Pb(II), Ca(II), and Zn(II) of a new octadentate ligand (py-H(2)bcpe) based on a ethane-1,2-diamine unit containing two picolinate and two pyridyl pendants, which is structurally derived from the previous reported ligand bcpe. Potentiometric studies have been carried out to determine the protonation constants of the ligand and the stability constants of the complexes with these cations. The introduction of the pyridyl pendants in bcpe provokes a very important increase of the logK(ML) values obtained for the Pb(II) and Cd(II) complexes, while this effect is less important in the case of the Zn(II) analogue. As a result, py-bcpe shows a certain selectivity for Cd(II) and Pb(II) over Zn(II) while keeping good Pb(II)/Ca(II) and Cd(II)/Ca(II) selectivities, and the new receptor py-bcpe can be considered as a new structural framework for the design of novel Cd(II) and Pb(II) extracting agents. Likewise, the stabilities of the Cd(II) and Pb(II) complexes are higher than those of the corresponding EDTA analogues. The X-ray crystal structure of [Zn(py-bcpe)] shows hexadentate binding of the ligand to the metal ion, the coordination polyhedron being best described as a severely distorted octahedron. However, the X-ray crystal structure of the Pb(II) analogue shows octadentate binding of the ligand to the metal ion. A detailed investigation of the structure in aqueous solution of the complexes by using nuclear magnetic resonance (NMR) techniques and density functional theory (DFT) calculations (B3LYP) shows that while in the Zn(II) complex the metal ion is six-coordinated, in the Pb(II) and Ca(II) analogues the metal ions are eight-coordinated. For the Cd(II) complex, our results suggest that in solution the complex exists as a mixture of seven- and eight-coordinated species. DFT calculations performed both in the gas phase and in aqueous solution have been also used to investigate the role of the Pb(II) lone pair in

  15. Proteins involved in electron transfer to Fe(III) and Mn(IV) oxides by Geobacter sulfurreducens and Geobacter uraniireducens.

    Science.gov (United States)

    Aklujkar, M; Coppi, M V; Leang, C; Kim, B C; Chavan, M A; Perpetua, L A; Giloteaux, L; Liu, A; Holmes, D E

    2013-03-01

    Whole-genome microarray analysis of Geobacter sulfurreducens grown on insoluble Fe(III) oxide or Mn(IV) oxide versus soluble Fe(III) citrate revealed significantly different expression patterns. The most upregulated genes, omcS and omcT, encode cell-surface c-type cytochromes, OmcS being required for Fe(III) and Mn(IV) oxide reduction. Other electron transport genes upregulated on both metal oxides included genes encoding putative menaquinol : ferricytochrome c oxidoreductase complexes Cbc4 and Cbc5, periplasmic c-type cytochromes Dhc2 and PccF, outer membrane c-type cytochromes OmcC, OmcG and OmcV, multicopper oxidase OmpB, the structural components of electrically conductive pili, PilA-N and PilA-C, and enzymes that detoxify reactive oxygen/nitrogen species. Genes upregulated on Fe(III) oxide encode putative menaquinol : ferricytochrome c oxidoreductase complexes Cbc3 and Cbc6, periplasmic c-type cytochromes, including PccG and PccJ, and outer membrane c-type cytochromes, including OmcA, OmcE, OmcH, OmcL, OmcN, OmcO and OmcP. Electron transport genes upregulated on Mn(IV) oxide encode periplasmic c-type cytochromes PccR, PgcA, PpcA and PpcD, outer membrane c-type cytochromes OmaB/OmaC, OmcB and OmcZ, multicopper oxidase OmpC and menaquinone-reducing enzymes. Genetic studies indicated that MacA, OmcB, OmcF, OmcG, OmcH, OmcI, OmcJ, OmcM, OmcV and PccH, the putative Cbc5 complex subunit CbcC and the putative Cbc3 complex subunit CbcV are important for reduction of Fe(III) oxide but not essential for Mn(IV) oxide reduction. Gene expression patterns for Geobacter uraniireducens were similar. These results demonstrate that the physiology of Fe(III)-reducing bacteria differs significantly during growth on different insoluble and soluble electron acceptors and emphasize the importance of c-type cytochromes for extracellular electron transfer in G. sulfurreducens.

  16. Hydrothermal self-assembly and supercapacitive behaviors of Co(II) ion-modified graphene aerogels in H{sub 2}SO{sub 4} electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Qi [Department of Systems Engineering and Engineering Management, City University of Hong Kong, Hong Kong (China); Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Hui, K.N., E-mail: bizhui@pusan.ac.kr [School of Materials Science and Engineering, Pusan National University, San 30 Jangjeon-dong, Geumjeong-gu, Busan 609-735 (Korea, Republic of); Hui, K.S., E-mail: kshui@hanyang.ac.kr [Department of Mechanical Convergence Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Wang, Yi [Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Hong, Xiaoting [Department of Systems Engineering and Engineering Management, City University of Hong Kong, Hong Kong (China)

    2014-08-15

    Highlights: • 3D Co(II) ions modified graphene aerogels were prepared by one-step hydrothermal process. • The aerogel electrodes showed hybrid supercapacitor behaviors. • The aerogel electrodes exhibited high rate capability and long-term cycling stability. - Abstract: Reduced graphene oxide (r-GO) aerogels decorated with divalent cobalt ions were synthesized via a one-pot hydrothermal self-assembly route. The interaction of Co(II) ions with 3D r-GO aerogels was investigated by spectroscopic techniques, including Raman, attenuated total reflectance infrared, and X-ray photoelectron spectroscopies. The excellent electrochemical properties of the aerogels were confirmed by cyclic voltammetry, galvanostatic charge/discharge tests, and electrochemical impedance spectroscopy in an acid electrolyte (1 M H{sub 2}SO{sub 4}). The Co(II) ion-modified r-GO aerogels can be used as high-performance hybrid supercapacitor materials with a specific capacitance of 387.2 F g{sup –1} at 1 A g{sup –1} current density and a good cycling stability without capacity decay over 1000 cycles. The mechanical integrity enhancement of the hybrid r-GO aerogel framework and the improvement in its unique capacitive performance are attributed to the efficient interconnection produced by electro-active Co(II) ions.

  17. Synthesis, Structure, and Reactivity of Co(II) and Ni(II) PCP Pincer Borohydride Complexes

    Science.gov (United States)

    2015-01-01

    The 15e square-planar complexes [Co(PCPMe-iPr)Cl] (2a) and [Co(PCP-tBu)Cl] (2b), respectively, react readily with NaBH4 to afford complexes [Co(PCPMe-iPr)(η2-BH4)] (4a) and [Co(PCP-tBu)(η2-BH4)] (4b) in high yields, as confirmed by IR spectroscopy, X-ray crystallography, and elemental analysis. The borohydride ligand is symmetrically bound to the cobalt center in η2-fashion. These compounds are paramagnetic with effective magnetic moments of 2.0(1) and 2.1(1) μB consistent with a d7 low-spin system corresponding to one unpaired electron. None of these complexes reacted with CO2 to give formate complexes. For structural and reactivity comparisons, we prepared the analogous Ni(II) borohydride complex [Ni(PCPMe-iPr)(η2-BH4)] (5) via two different synthetic routes. One utilizes [Ni(PCPMe-iPr)Cl] (3) and NaBH4, the second one makes use of the hydride complex [Ni(PCPMe-iPr)H] (6) and BH3·THF. In both cases, 5 is obtained in high yields. In contrast to 4a and 4b, the borohydride ligand is asymmetrically bound to the nickel center but still in an η2-mode. [Ni(PCPMe-iPr)(η2-BH4)] (5) loses readily BH3 at elevated temperatures in the presence of NEt3 to form 6. Complexes 5 and 6 are both diamagnetic and were characterized by a combination of 1H, 13C{1H}, and 31P{1H} NMR, IR spectroscopy, and elemental analysis. Additionally, the structure of these compounds was established by X-ray crystallography. Complexes 5 and 6 react with CO2 to give the formate complex [Ni(PCPMe-iPr)(OC(C=O)H] (7). The extrusion of BH3 from [Co(PCPMe-iPr)(η2-BH4)] (4a) and [Ni(PCPMe-iPr)(η2-BH4)] (5) with the aid of NH3 to yield the respective hydride complexes [Co(PCPMe-iPr)H] and [Ni(PCPMe-iPr)H] (6) and BH3NH3 was investigated by DFT calculations showing that formation of the Ni hydride is thermodynamically favorable, whereas the formation of the Co(II) hydride, in agreement with the experiment, is unfavorable. The electronic structures and the bonding of the borohydride ligand in [Co

  18. Secondary ligand-directed assembly of Co(II) coordination polymers based on a pyridine carboxylate ligand

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Ke-Li; Zhang, Yi-Ping; Cai, Yi-Ni; Xu, Xiao-Wei; Feng, Yun-Long, E-mail: sky37@zjnu.cn

    2014-07-01

    To investigate the influence of hydrogen bonds and secondary ligands on the structures and properties of the resulting frameworks, five new Co(II) compounds have been synthesized by the reactions of Co(II) salts and 3,5-bis(pyridin-4-ylmethoxy)benzoic acid (HL) with four rationally selected dicarboxylic acid ligands. Without secondary ligand, we got one compound [CoL{sub 2}(H{sub 2}O){sub 2}]{sub n}·2nH{sub 2}O (1), which possesses a 1D chain structure. In the presence of ancillary ligands, namely, 1,3-adamantanedicarboxylic acid (H{sub 2}adbc), terephthalic acid (H{sub 2}tpa), thiophene-2,5-dicarboxylic acid (H{sub 2}tdc) and 1,4-benzenedithioacetic acid (H{sub 2}bdtc), four 3D structures [Co{sub 2}L{sub 2}(adbc)]{sub n}·nH{sub 2}O (2), [Co{sub 2}L{sub 2}(tpa)]{sub n} (3), [Co{sub 2}L{sub 2}(tdc)]{sub n} (4), [Co{sub 2}L{sub 2}(bdtc)(H{sub 2}O)]{sub n} (5) were obtained, respectively. It can be observed from the architectures of 1–5 that hydrogen bonds and secondary ligands both have great effects on the spatial connective fashions, resulting in the formation of various dimensional compounds. The XRPD, TGA data of title polymers and the magnetic properties for 2 and 5 have also been investigated. - Graphical abstract: The structural differences show that the ancillary ligands have great effects on the spatial connective fashions, resulting in the formation of various dimensional compounds. - Highlights: • Five new Co(II) coordination polymers have been synthesized by solvothermal reactions based on 3,5-bis(pyridin-4-ylmethoxy)benzoic acid (HL). • The long-flexible ligand (HL) is a good candidate to produce interpenetrating architectures. • The secondary dicarboxylic acid ligands play important roles in the spatial connective fashions and the formation of various dimensional compounds. • The magnetism studies show that both 2 and 5 exhibit antiferromagnetic interactions.

  19. Crystal structures and luminescence properties of two Cd(II) complexes based on 2-(1H-imidazol-1methyl)-6-methyl-1H-benzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuhong; Meng, Xiangru; Wen, Yu; Li, Peng; Ma, Lin [Zhengzhou Univ. (China). College of Chemistry and Molecular Engineering; Zhang, Qiuju [Zhengzhou Univ. (China). Clinical Testing Section

    2015-11-01

    Two new complexes, {[Cd(immb)I_2].DMF}{sub n} (1) and {[Cd_3(immb)(btc)_2]. H_2O}{sub n} (2) (immb = 2-(1H-imidazol- 1-methyl)-6-methyl-1H-benzimidazole, btc = 1,2,3-benzenetricarboxylate, DMF = dimethyl formamide), have been synthesized and characterized. Single crystal X-ray diffraction shows that 1 exhibits a chain structure constructed by immb ligands bridging Cd(II) ions. In 2, Cd(II) ions are linked by immb ligands with bridging mode and btc3- anions with the μ{sub 2}-η{sup 2}:η{sup 1} bonding pattern leading to a 2D structure. Luminescent properties have been investigated in the solid state at room temperature.

  20. Separation/preconcentration of trace Pb(II and Cd(II with 2-mercaptobenzothiazole impregnated Amberlite XAD-1180 resin and their determination by flame atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Şerife Tokalıoğlu

    2017-01-01

    Full Text Available A new chelating resin, 2-mercaptobenzothiazole loaded Amberlite XAD-1180 was prepared and used for separation and preconcentration of Cd(II and Pb(II ions prior to their determinations by flame atomic absorption spectrometry. The optimum pH for simultaneous retention of the elements and the best elution means for their simultaneous elution were 9.5 and 2 mol L−1 HNO3, respectively. The detection limits for Cd(II and Pb(II were 0.35 and 5.0 μg L−1, respectively. The accuracy of the method was confırmed both by analyzing the certified reference material (RM 8704 Buffalo river sediment and performing recovery studies.

  1. Effect of desferrioxamine B and Suwannee River fulvic acid on Fe(III) release and Cr(III) desorption from goethite

    Science.gov (United States)

    Stewart, Angela G.; Hudson-Edwards, Karen A.; Dubbin, William E.

    2016-04-01

    Siderophores are biogenic chelating ligands that facilitate the solubilisation of Fe(III) and form stable complexes with a range of contaminant metals and therefore may significantly affect their biogeochemical cycling. Desferrioxamine B (DFOB) is a trihydroxamate siderophore that acts synergistically with fulvic acid and low molecular weight organic ligands to release Fe from Fe(III) oxides. We report the results of batch dissolution experiments in which we determine the rates of Cr(III) desorption and Fe(III) release from Cr(III)-treated synthetic goethite as influenced by DFOB, by fulvic acid, and by the two compounds in combination. We observed that adsorbed Cr(III) at 3% surface coverage significantly reduced Fe(III) release from goethite for all combinations of DFOB and fulvic acid. When DFOB (270 μM) was the only ligand present, dissolved Fe(III) and Cr(III) increased approximately 1000-fold and 16-fold, respectively, as compared to the ligand-free system, a difference we attribute to the slow rate of water exchange of Cr(III). Suwannee River fulvic acid (SRFA) acts synergistically with DFOB by (i) reducing the goethite surface charge leading to increased HDFOB+ surface excess and by (ii) forming aqueous Fe(III)-SRFA species whose Fe(III) is subsequently removed by DFOB to yield aqueous Fe(III)-DFOB complexes. These observations shed new light on the synergistic relationship between DFOB and fulvic acid and reveal the mechanisms of Fe(III) acquisition available to plants and micro-organisms in Cr(III) contaminated environments.

  2. INFLUENCIA DEL pH SOBRE LA ADSORCIÓN EN CARBÓN ACTIVADO DE Cd(II Y Ni(II DESDE SOLUCIONES ACUOSAS

    Directory of Open Access Journals (Sweden)

    Paola Rodríguez

    2011-01-01

    Full Text Available La adsorción de iones Cd(II y Ni(II desde soluciones acuosas sobre carbón activado se estudia con diferentes valores de pH. La adsorción de los iones se realiza en dos condiciones de pH de la solución: en la primera el pH varía en el transcurso del proceso a medida que los iones se adsorben y en la segunda el pH se mantiene fijo durante la adsorción. Cuando no se realiza un control en el pH de la solución se observan incrementos en la concentración de los iones hidronio que alcanzan un valor máximo alrededor de pH 4, para los dos iones, y cuyos valores son de 346 mmol mL-1 para el caso de la adsorción de Cd(II y de 436 mmol mL-1 para el Ni(II. Para todos los valores de pH y las dos condiciones del proceso de adsorción se observa una mayor cantidad de Ni(II adsorbida con valores entre 0,04 y 0,42 mmol.g-1, mientras que para el Cd(II la máxima cantidad adsorbida es de 0,16 mmol.g-1. El aumento de los iones hidronio en las soluciones de Cd(II y Ni(II, en las que no se controla el valor del pH, favorece el proceso de adsorción, en tanto que al mantener un pH fijo en la solución, se obtienen adsorciones menores de los iones.

  3. Seizure modeling of Pb(II) and Cd(II) from aqueous solution by chemically modified sugarcane bagasse fly ash: isotherms, kinetics, and column study.

    Science.gov (United States)

    Shah, Bhavna; Mistry, Chirag; Shah, Ajay

    2013-04-01

    Heavy metal pollution is a common environmental problem all over the world. The purpose of the research is to examine the applicability of bagasse fly ash (BFA)-an agricultural waste of sugar industry used for the synthesis of zeolitic material. The zeolitic material are used for the uptake of Pb(II) and Cd(II) heavy metal. Bagasse fly ash is used as a native material for the synthesis of zeolitic materials by conventional hydrothermal treatment without (conventional zeolitic bagasse fly ash (CZBFA)) and with electrolyte (conventional zeolitic bagasse fly ash in electrolyte media (ECZBFA)) media. Heavy metal ions Pb(II) and Cd(II) were successfully seized from aqueous media using these synthesized zeolitic materials. In this study, the zeolitic materials were well characterized by different instrumental methods such as Brunauer-Emmett-Teller, XRF, Fourier transform infrared spectroscopy, powder X-ray diffraction, and scanning electron microscopic microphotographs. The presence of analcime, phillipsite, and zeolite P in adsorbents confirms successful conversion of native BFA into zeolitic materials. Seizure modeling of Pb(II) and Cd(II) was achieved by batch sorption experiments, isotherms, and kinetic studies. These data were used to compare and evaluate the zeolitic materials as potential sorbents for the uptake of heavy metal ions from an aqueous media. The Langmuir isotherm correlation coefficient parameters best fit the equilibrium data which indicate the physical sorption. Pseudo-second-order and intra-particle diffusion model matches best which indicates that the rate of sorption was controlled by film diffusion. The column studies were performed for the practical function of sorbents, and breakthrough curves were obtained, which revealed higher sorption capacity as compared to batch method. Synthesized zeolitic material (CZBFA and ECZBFA), a low-cost sorbent, was proven as potential sorbent for the uptake of Pb(II) and Cd(II) heavy metal ions.

  4. Kinetics of metal exchange in Cd(II) octa(4-bromophenyl)porphyrinate with d-metal salts in organic solvents

    Science.gov (United States)

    Zvezdina, S. V.; Chizhova, N. V.; Mamardashvili, N. Zh.

    2017-03-01

    The reaction of metal exchange between Cd(II) octa(4-bromophenyl)porphyrinate with CuCl2 and ZnCl2 in DMFA and DMSO is studied by means of spectrophotometry. The kinetic parameters of the metal exchange reaction are calculated, a stoichiometric reaction mechanism is proposed. The effect the natures of the solvent, salt solvate, and the chemical modification of tetrapyrrole macrocycle have on the kinetic parameters of the metal exchange reaction are revealed.

  5. Crystal structure and photoluminescence of a new two-dimensional Cd(II) coordination polymer based on 3-(carboxymethoxy)-2-naphthoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Zhi-Guo; Guo, Sheng-Nan; Miao, Jia-Qi; An, Miao [Jilin Normal Univ., College of Chemistry, Siping (China); Ministry of Education, Siping (China). Key Lab. of Preparation and Applications of Enviromental Friendly Materials

    2015-11-01

    A new Cd(II) coordination polymer, [Cd(CNA)]{sub n} (1) (H{sub 2}CNA = 3-(carboxymethoxy)-2-naphthoic acid), was hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. The crystals are monoclinic, space group P{sub 2}1/c with a = 16.9698(18), b = 7.8314(8), c = 8.9553(10) Aa, β = 100.657(2) {sup circle}, V = 1169.6(2) Aa{sup 3}, Z = 4, D{sub calcd.} = 2.03 g cm{sup -3}, μ(MoK{sub α}) = 1.9 mm{sup -1}, F(000) = 696 e, R = 0.0305, wR = 0.0784 for 172 refined parameters and 2285 data. Each CNA anion bridges three Cd(II) cations to give rise to a two-dimensional network structure. Topologically, if each CNA anion is regarded as a linker, and each Cd(II) atom considered as a 4-connected node, the structure is simplified as a 4-connected (4,4) network. The solid state photoluminescent properties of the compound were also studied at room temperature.

  6. Mechanism of Cu(II), Cd(II) and Pb(II) ions sorption from aqueous solutions by macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate)

    Science.gov (United States)

    Nastasović, Aleksandra B.; Ekmeščić, Bojana M.; Sandić, Zvjezdana P.; Ranđelović, Danijela V.; Mozetič, Miran; Vesel, Alenka; Onjia, Antonije E.

    2016-11-01

    The mechanism of Cu(II), Cd(II) and Pb(II) ions sorption from aqueous solutions by macroporous poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) (PGME) functionalized by reaction of the pendant epoxy groups with diethylene triamine (PGME-deta) was studied using X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis. Atomic force microscopy (AFM) and scanning energy-dispersive X-ray spectroscopy (SEM-EDX) were used for the determination of surface morphology of the copolymer particles. The sorption behavior of heavy metals Cu(II), Cd(II) and Pb(II) ions sorption was investigated in batch static experiments under non-competitive conditions at room temperature (298 K). The obtained results were fitted to pseudo-first order, pseudo-second order and intraparticle diffusion kinetic model. The kinetics studies showed that Cu(II), Cd(II) and Pb(II) sorption obeys the pseudo-second-order model under all investigated operating conditions with evident influence of pore diffusion.

  7. Six Zn(II) and Cd(II) coordination polymers assembled from a similar binuclear building unit: tunable structures and luminescence properties.

    Science.gov (United States)

    Zhang, Liyan; Rong, Lulu; Hu, Guoli; Jin, Suo; Jia, Wei-Guo; Liu, Ji; Yuan, Guozan

    2015-04-21

    Six Zn(ii) and Cd(ii) coordination polymers were constructed by treating a 2-substituted 8-hydroxyquinolinate ligand containing a pyridyl group with zinc or cadmium salts, and characterized by a variety of techniques. Interestingly, based on a similar binuclear Zn(ii) or Cd(ii) building unit, the supramolecular structures of the six coordination polymers () exhibit an unprecedented structural diversification due to the different choices of metal salts. and represent a novel 2D framework containing 1D infinite right- and left-handed helical chains. and are 2D coordination frameworks based on binuclear Cd(ii) building units. For and , the L ligands can bridge binuclear building units forming a 1D infinite chain. Interestingly, the adjacent Cd2O2 planes of the 1D chain in are in parallel with each other, while the dihedral angle between the two Zn2O2 planes in is 83.43°. Photoluminescence properties revealed that the six coordination polymers exhibit redshifted emission maximum compared with the free ligand HL, which can be ascribed to an increased conformational rigidity and the fabrication of coplanar binuclear building units M2L2 in . Coordination polymers also display distinct fluorescence lifetimes and quantum yields because of their different metal centers and supramolecular structures.

  8. Preparation of cross-linked magnetic chitosan-phenylthiourea resin for adsorption of Hg(II), Cd(II) and Zn(II) ions from aqueous solutions.

    Science.gov (United States)

    Monier, M; Abdel-Latif, D A

    2012-03-30

    In this study, cross-linked magnetic chitosan-phenylthiourea (CSTU) resin were prepared and characterized by means of FTIR, (1)H NMR, SEM high-angle X-ray diffraction (XRD), magnetic properties and thermogravimetric analysis (TGA). The prepared resin were used to investigate the adsorption properties of Hg(II), Cd(II) and Zn(II) metal ions in an aqueous solution. The extent of adsorption was investigated as a function of pH and the metal ion removal reached maximum at pH 5.0. Also, the kinetic and thermodynamic parameters of the adsorption process were estimated. These data indicated that the adsorption process is exothermic and followed the pseudo-second-order kinetics. Equilibrium studies showed that the data of Hg(II), Cd(II) and Zn(II) adsorption followed the Langmuir model. The maximum adsorption capacities for Hg(II), Cd(II) and Zn(II) were estimated to be 135 ± 3, 120 ± 1 and 52 ± 1 mg/g, which demonstrated the high adsorption efficiency of CSTU toward the studied metal ions.

  9. Adsorption Study of Pb(II, Cd(II, Hg(II And Cr(III Onto Calix[4]Resorcinarene Derivative

    Directory of Open Access Journals (Sweden)

    Chairil Anwar

    2016-11-01

    Full Text Available In this study, the removal of several heavy metal ions of Pb(II, Cd(II, Hg(II and Cr(III from aqueous medium via sorption process onto calix[4]resorcinarene derivative was investigated. The used adsorbent was highly oxygenated calix[4]resorcinarene namely C-4-hydroxyphenylcalix[4]resorcinarene. Several adsorption parameters were studied including pH, adsorbent dosage, interaction time as well as the kinetic studies. While the maximum removals of Pb(II, Cd(II and Hg(II were observed in pH 5, the removal of Cr(III reached the maximum value at pH 6. The optimum adsorbent dosages for Pb(II, Hg(II and Cr(III were 0.025 g, whereas that for Cd(II was 0.05 g. The kinetic data were evaluated by using three kinetic models of first order model of Santosa, pseudo-first order of Lagergren and pseudo-second order of Ho. The results showed that the adsorption of these metal ions could be well described with Ho's pseudo-first order model.

  10. Synthesis, characterization, DFT and biological studies of isatinpicolinohydrazone and its Zn(II), Cd(II) and Hg(II) complexes

    Science.gov (United States)

    El-Gammal, O. A.; Rakha, T. H.; Metwally, H. M.; Abu El-Reash, G. M.

    2014-06-01

    Isatinpicolinohydrazone (H2IPH) and its Zn(II), Cd(II) and Hg(II) complexes have been synthesized and investigated using physicochemical techniques viz. IR, 1H NMR, 13C NMR, UV-Vis spectrometric methods and magnetic moment measurements. The investigation revealed that H2IPH acts as binegative tetradentate in Zn(II), neutral tridentate in Cd(II) and as neutral bidentate towards Hg(II) complex. Octahedral geometry is proposed for all complexes. The bond length, bond angle, chemical reactivity, energy components (kcal/mol), binding energy (kcal/mol) and dipole moment (Debyes) for all the title compounds were evaluated by DFT and also MEP for the ligand is shown. Theoretical infrared intensities of H2IPH and also the theoretical electronic spectra of the ligand and its complexes were calculated. The thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. The in vitro antibacterial studies of the complexes proved them as growth inhibiting agents. The DDPH antioxidant of the compounds have been screened. Antitumor activity, carried out in vitro on human mammary gland (breast) MCF7, have shown that Hg(II) complex exhibited potent activity followed by Zn(II), Cd(II) complexes and the ligand.

  11. Mononuclear, dinuclear and 1-D polymeric complexes of Cd(II) of a pyridyl pyrazole ligand: Syntheses, crystal structures and photoluminescence studies

    Science.gov (United States)

    Das, Kinsuk; Konar, Saugata; Jana, Atanu; Barik, Anil Kumar; Roy, Sangita; Kar, Susanta Kumar

    2013-03-01

    The syntheses, crystal structures and photoluminescence properties of four new Cd(II) complexes are reported using strongly coordinating ligand 3,5-dimethyl-1-(2'-pyridyl) pyrazole (L) in presence of anionic ancillary bridging ligands as nitrite, chloride and dicyanamide. Among the complexes two (1 and 2) are monomeric, 3 is μ2 - chloro bridged dimer and the last one (4) is a mixed alternate chloro - end to end (EE) dicyanamide bridged 1D polymer. All the four complexes have been X-ray crystallographically characterized. The ligand L behaves as a potent bidentate neutral N, N donor. Geometrical diversity of Cd(II) complexes is due to no loss or gain of crystal field stability with the variation of geometry. Consequently the stability of a structure depends on steric requirements. The ligand L shows considerable fluorescence and all four complexes in methanol exhibit interesting photoluminescence properties with different emission intensities. The band maxima and fluorescence efficiency (in methanol) are found to be dependent on the coordination chromophore and structural rigidity induced by the incorporated Cd(II) ion. Among the synthesized complexes 1 exhibits the highest fluorescence intensity in methanol.

  12. Detection of mitochondrial COII DNA sequences in ant guts as a method for assessing termite predation by ants.

    Science.gov (United States)

    Fayle, Tom M; Scholtz, Olivia; Dumbrell, Alex J; Russell, Stephen; Segar, Simon T; Eggleton, Paul

    2015-01-01

    Termites and ants contribute more to animal biomass in tropical rain forests than any other single group and perform vital ecosystem functions. Although ants prey on termites, at the community level the linkage between these groups is poorly understood. Thus, assessing the distribution and specificity of ant termitophagy is of considerable interest. We describe an approach for quantifying ant-termite food webs by sequencing termite DNA (cytochrome c oxidase subunit II, COII) from ant guts and apply this to a soil-dwelling ant community from tropical rain forest in Gabon. We extracted DNA from 215 ants from 15 species. Of these, 17.2 % of individuals had termite DNA in their guts, with BLAST analysis confirming the identity of 34.1 % of these termites to family level or better. Although ant species varied in detection of termite DNA, ranging from 63 % (5/7; Camponotus sp. 1) to 0 % (0/7; Ponera sp. 1), there was no evidence (with small sample sizes) for heterogeneity in termite consumption across ant taxa, and no evidence for species-specific ant-termite predation. In all three ant species with identifiable termite DNA in multiple individuals, multiple termite species were represented. Furthermore, the two termite species that were detected on multiple occasions in ant guts were in both cases found in multiple ant species, suggesting that ant-termite food webs are not strongly compartmentalised. However, two ant species were found to consume only Anoplotermes-group termites, indicating possible predatory specialisation at a higher taxonomic level. Using a laboratory feeding test, we were able to detect termite COII sequences in ant guts up to 2 h after feeding, indicating that our method only detects recent feeding events. Our data provide tentative support for the hypothesis that unspecialised termite predation by ants is widespread and highlight the use of molecular approaches for future studies of ant-termite food webs.

  13. Detection of mitochondrial COII DNA sequences in ant guts as a method for assessing termite predation by ants.

    Directory of Open Access Journals (Sweden)

    Tom M Fayle

    Full Text Available Termites and ants contribute more to animal biomass in tropical rain forests than any other single group and perform vital ecosystem functions. Although ants prey on termites, at the community level the linkage between these groups is poorly understood. Thus, assessing the distribution and specificity of ant termitophagy is of considerable interest. We describe an approach for quantifying ant-termite food webs by sequencing termite DNA (cytochrome c oxidase subunit II, COII from ant guts and apply this to a soil-dwelling ant community from tropical rain forest in Gabon. We extracted DNA from 215 ants from 15 species. Of these, 17.2 % of individuals had termite DNA in their guts, with BLAST analysis confirming the identity of 34.1 % of these termites to family level or better. Although ant species varied in detection of termite DNA, ranging from 63 % (5/7; Camponotus sp. 1 to 0 % (0/7; Ponera sp. 1, there was no evidence (with small sample sizes for heterogeneity in termite consumption across ant taxa, and no evidence for species-specific ant-termite predation. In all three ant species with identifiable termite DNA in multiple individuals, multiple termite species were represented. Furthermore, the two termite species that were detected on multiple occasions in ant guts were in both cases found in multiple ant species, suggesting that ant-termite food webs are not strongly compartmentalised. However, two ant species were found to consume only Anoplotermes-group termites, indicating possible predatory specialisation at a higher taxonomic level. Using a laboratory feeding test, we were able to detect termite COII sequences in ant guts up to 2 h after feeding, indicating that our method only detects recent feeding events. Our data provide tentative support for the hypothesis that unspecialised termite predation by ants is widespread and highlight the use of molecular approaches for future studies of ant-termite food webs.

  14. Heterogeneous Reduction of PuO2 with Fe(II): Importance of the Fe(III) Reaction Product

    Energy Technology Data Exchange (ETDEWEB)

    Felmy, Andrew R.; Moore, Dean A.; Rosso, Kevin M.; Qafoku, Odeta; Rai, Dhanpat; Buck, Edgar C.; Ilton, Eugene S.

    2011-05-01

    Abstract Heterogeneous reduction of actinides in higher and more soluble oxidation states to lower more insoluble oxidation states by reductants such as Fe(II) has been the subject of intensive study for more than two decades. However, Fe(II)-induced reduction of sparingly soluble Pu(IV) to the more soluble lower oxidation state Pu(III) has been much less studied even though such reactions can potentially increase the mobility of Pu in the subsurface. Thermodynamic calculations are presented that show how differences in the free energy of various possible solid-phase Fe(III) reaction products can greatly influence aqueous Pu(III) concentrations resulting from reduction of PuO2(am) by Fe(II). We present the first experimental evidence that reduction of PuO2(am) to Pu(III) by Fe(II) was enhanced when the Fe(III) mineral goethite was spiked into the reaction. The effect of goethite on reduction of Pu(IV) was demonstrated by measuring the time-dependence of total aqueous Pu concentration, its oxidation state, and system pe/pH. We also re-evaluated established protocols for determining Pu(III) [(Pu(III) + Pu(IV)) - Pu(IV)] by using thenoyltrifluoroacetone (TTA) in toluene extractions; the study showed that it is important to eliminate dissolved oxygen from the TTA solutions for accurate determinations. More broadly, this study highlights the importance of the Fe(III) reaction product in actinide reduction rate and extent by Fe(II).

  15. Synthesis and Structural Studies of Cr(III, Mn(II and Fe(III Complexes of N(2-Benzimidazolylacetylacetohydrazone

    Directory of Open Access Journals (Sweden)

    G. H. Anuradha

    2011-01-01

    Full Text Available The ligand N(2-benzimidazolylacetylacetohydrazone (BAAH have been synthesized and characterized. Coordination complexes of Cr(III, Mn(II and Fe(III have been synthesized with the ligand BAAH. These complexes were characterized on the basis of analytical, conductance, thermal, magnetic data and infrared and electronic spectral data. The ligand BAAH is behaving as a neutral tridentate NNO donar employing two azomethine nitrogens (ring and side chain and carbonyl oxygen. The ligand and it's metal complexes were tested for anti microbial activity on the gram positive S. Aureus, E. coli and Proteus.

  16. Adsorption of Cd(II) and Pb(II) by in situ oxidized Fe3O4 membrane grafted on 316L porous stainless steel filter tube and its potential application for drinking water treatment.

    Science.gov (United States)

    Zhu, Mengfei; Zhu, Li; Wang, Jianlong; Yue, Tianli; Li, Ronghua; Li, Zhonghong

    2017-03-08

    Removing heavy metal ions from aqueous solutions is one of the most challenging separations. In situ oxidized Fe3O4 membranes using 316L porous stainless steel filter tube have shown great potential for removing anion Cr(VI). Here we report the performances of the in situ oxidized Fe3O4 membranes for removing two toxic cations Cd(II) and Pb(II) commonly existing in water and their potential applications for drinking water purification. The membranes exhibited high removal efficiency: 97% at pH 9.0 for Cd(II) of 1.0 mg/L initial concentration and 100% at pH 5.0-6.0 for Pb(II) of 5.0 mg/L initial concentration. The maximum adsorption capabilities were estimated at 0.800 mg/g and 2.251 mg/g respectively for Cd(II) and Pb(II) at 318 K by the Langmuir model. Results of batch tests revealed the existence of electrostatic attraction and chemisorption. XRD and FT-IR analyses indicated that the chemisorption might be the insertion of Cd(II) and Pb(II) into the Fe3O4 crystal faces of 311 and 511 to form mononuclear or binuclear coordination with O atoms of Fe-O6 groups. Competitive adsorption of Cd(II) and Pb(II) in binary solutions revealed a preferential adsorption for Pb(II). Na2EDTA solution was used to regenerate the membranes, and the maximum desorption ratio was 90.29% and 99.75% respectively for Cd(II) and Pb(II). The membranes were able to efficiently lower Cd(II) and Pb(II) concentrations to meet the drinking water standards recommended by the World Health Organization and are promising for engineering applications aimed at drinking water purification.

  17. Dissimilatory reduction of FeIII (EDTA) with microorganisms in the system of nitric oxide removal from the flue gas by metal chelate absorption

    Institute of Scientific and Technical Information of China (English)

    MA Bi-yao; LI Wei; JING Guo-hua; SHI Yao

    2004-01-01

    In the system of nitric oxide removal from the flue gas by metal chelate absorption, it is an obstacle that ferrous absorbents are easily oxidized by oxygen in the flue gas to ferric counterparts, which are not capable of binding NO. By adding iron metal or electrochemical method, FeIII (EDTA) can be reduced to FeII (EDTA). However, there are various drawbacks associated with these techniques. The dissimilatory reduction of FeIII (EDTA) with microorganisms in the system of nitric oxide removal by metal chelate absorption was investigated. Ammonium salt instead of nitrate was used as the nitrogen source, as nitrates inhibited the reduction of FeIII due to the competition between the two electron acceptors. Supplemental glucose and lactate stimulated the formation of FeII more than ethanol as the carbon sources. The microorganisms cultured at 50℃ were not very sensitive to the other experimental temperature, the reduction percentage of FeIII varied little with the temperature range of 30~50℃. Concentrated Na2CO3 solution was added to adjust the solution pH to an optimal pH range of 6~7. The overall results revealed that the dissimilatory ferric reducing microorganisms present in the mix-culture are probably neutrophilic, moderately thermophilic FeIII reducers.

  18. Effects of microbial iron reduction and oxidation on the immobilization and mobilization of copper in synthesized Fe(III) minerals and Fe-rich soils.

    Science.gov (United States)

    Hu, Chaohua; Zhang, Youchi; Zhang, Lei; Luo, Wensui

    2014-04-01

    The effects of microbial iron reduction and oxidation on the immobilization and mobilization of copper were investigated in a high concentration of sulfate with synthesized Fe(III) minerals and red earth soils rich in amorphous Fe (hydr)oxides. Batch microcosm experiments showed that red earth soil inoculated with subsurface sediments had a faster Fe(III) bioreduction rate than pure amorphous Fe(III) minerals and resulted in quicker immobilization of Cu in the aqueous fraction. Coinciding with the decrease of aqueous Cu, SO4(2-) in the inoculated red earth soil decreased acutely after incubation. The shift in the microbial community composite in the inoculated soil was analyzed through denaturing gradient gel electrophoresis. Results revealed the potential cooperative effect of microbial Fe(III) reduction and sulfate reduction on copper immobilization. After exposure to air for 144 h, more than 50% of the immobilized Cu was remobilized from the anaerobic matrices; aqueous sulfate increased significantly. Sequential extraction analysis demonstrated that the organic matter/sulfide-bound Cu increased by 52% after anaerobic incubation relative to the abiotic treatment but decreased by 32% after oxidation, indicating the generation and oxidation of Cu-sulfide coprecipitates in the inoculated red earth soil. These findings suggest that the immobilization of copper could be enhanced by mediating microbial Fe(III) reduction with sulfate reduction under anaerobic conditions. The findings have an important implication for bioremediation in Cucontaminated and Fe-rich soils, especially in acid-mine-drainage-affected sites.

  19. Enhanced abiotic and biotic contributions to dechlorination of pentachlorophenol during Fe(III) reduction by an iron-reducing bacterium Clostridium beijerinckii Z

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yan [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); He, Yan, E-mail: yhe2006@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Feng, Xiaoli [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Liang, Luyi [Experiment Teaching Center for Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Xu, Jianming, E-mail: jmxu@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Brookes, Philip C.; Wu, Jianjun [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China)

    2014-03-01

    A novel Fe(III) reducing bacterium, Clostridium beijerinckii Z, was isolated from glucose amended paddy slurries, and shown to dechlorinate pentachlorophenol (PCP). Fifty percent of added PCP was removed by C. beijerinckii Z alone, which increased to 83% in the presence of both C. beijerinckii Z and ferrihydrite after 11 days of incubation. Without C. beijerinckii Z, the surface-bound Fe(II) also abiotically dechlorinated more than 40% of the added PCP. This indicated that the biotic dechlorination by C. beijerinckii Z is a dominant process causing PCP transformation through anaerobic dechlorination, and that the dechlorination rates can be accelerated by simultaneous reduction of Fe(III). A biochemical electron transfer coupling process between sorbed Fe(II) produced by C. beijerinckii Z and reductive dehalogenation is a possible mechanism. This finding increases our knowledge of the role of Fe(III) reducing genera of Clostridium in dechlorinating halogenated organic pollutants, such as PCP, in anaerobic paddy soils. - Highlights: • A novel Fe(III) reducing bacterium Clostridium beijerinckii Z was isolated and could dechlorinate pentachlorophenol. • Anaerobic transformation of PCP by C. beijerinckii Z could be accelerated by simultaneous reduction of Fe(III). • Biochemical electron transfer coupling between Fe redox cycling and reductive dechlorination was the mechanism involved. • The finding increases our knowledge of Clostridium sp. regarding their multiple functions for dechlorinating pollutants.

  20. Fe(III) fertilization mitigating net global warming potential and greenhouse gas intensity in paddy rice-wheat rotation systems in China.

    Science.gov (United States)

    Liu, Shuwei; Zhang, Ling; Liu, Qiaohui; Zou, Jianwen

    2012-05-01

    A complete accounting of net greenhouse gas balance (NGHGB) and greenhouse gas intensity (GHGI) affected by Fe(III) fertilizer application was examined in typical annual paddy rice-winter wheat rotation cropping systems in southeast China. Annual fluxes of soil carbon dioxide (CO(2)), methane (CH(4)) and nitrous oxide (N(2)O) were measured using static chamber method, and the net ecosystem exchange of CO(2) (NEE) was determined by the difference between soil CO(2) emissions (R(H)) and net primary production (NPP). Fe(III) fertilizer application significantly decreased R(H) without adverse effects on NPP of rice and winter wheat. Fe(III) fertilizer application decreased seasonal CH(4) by 27-44%, but increased annual N(2)O by 65-100%. Overall, Fe(III) fertilizer application decreased the annual NGHGB and GHGI by 35-47% and 30-36%, respectively. High grain yield and low greenhouse gas intensity can be reconciled by Fe(III) fertilizer applied at the local recommendation rate in rice-based cropping systems.

  1. Synthesis of Imine-Naphthol Tripodal Ligand and Study of Its Coordination Behaviour towards Fe(III, Al(III, and Cr(III Metal Ions

    Directory of Open Access Journals (Sweden)

    Kirandeep Kaur

    2014-01-01

    Full Text Available A hexadentate Schiff base tripodal ligand is synthesized by the condensation of tris (2-aminoethyl amine with 2-hydroxy-1-naphthaldehyde and characterized by various spectroscopic techniques like UV-VIS, IR, NMR, MASS, and elemental analysis. The solution studies by potentiometric and spectrophotometric methods are done at 25 ± 1°C, µ=0.1 M KCl, to calculate the protonation constants of the ligand and formation constants of metal complexes formed by the ligand with Fe(III, Al(III, and Cr(III metal ions. The affinity of the ligand towards Fe(III is compared with deferiprone (a drug applied for iron intoxication and transferrin (the main Fe(III binding protein in plasma. Structural analysis of the ligand and the metal complexes was done using semiempirical PM6 method. Electronic and IR spectra are calculated by semiempirical methods and compared with experimental one.

  2. Synthesis of Imine-Naphthol Tripodal Ligand and Study of Its Coordination Behaviour towards Fe(III), Al(III), and Cr(III) Metal Ions.

    Science.gov (United States)

    Kaur, Kirandeep; Baral, Minati

    2014-01-01

    A hexadentate Schiff base tripodal ligand is synthesized by the condensation of tris (2-aminoethyl) amine with 2-hydroxy-1-naphthaldehyde and characterized by various spectroscopic techniques like UV-VIS, IR, NMR, MASS, and elemental analysis. The solution studies by potentiometric and spectrophotometric methods are done at 25 ± 1°C, µ = 0.1 M KCl, to calculate the protonation constants of the ligand and formation constants of metal complexes formed by the ligand with Fe(III), Al(III), and Cr(III) metal ions. The affinity of the ligand towards Fe(III) is compared with deferiprone (a drug applied for iron intoxication) and transferrin (the main Fe(III) binding protein in plasma). Structural analysis of the ligand and the metal complexes was done using semiempirical PM6 method. Electronic and IR spectra are calculated by semiempirical methods and compared with experimental one.

  3. Selective separation of Hg(II) and Cd(II) from aqueous solutions by complexation-ultrafiltration process.

    Science.gov (United States)

    Zeng, Jian Xian; Ye, Hong Qi; Huang, Nian Dong; Liu, Jun Feng; Zheng, Li Feng

    2009-07-01

    Complexation-ultrafiltration process was investigated to separate selectively Hg(II) and Cd(II) from binary metal solutions by using poly (acrylic acid) sodium salt as a complexing agent. Effects of operating parameters on selective separation factors (beta(Cd/Hg)) of the both metals have been examined in detail. Results indicated that loading rate, pH, concentration of salt added and low-molecular competitive complexing agent affect significantly beta(Cd/Hg) value. Further, a concentration experiment was carried out according to the previous optimum parameters. Rejection coefficient of mercury is close to 1, while that of cadmium is about 0.1. The experiment was characterized by good effectiveness, and enabled the rapid linear increase of mercury concentration and very slow increase of cadmium concentration in the retentate. Then, a diafiltration technique was applied to separate further the both metals. Cadmium concentration in the retentate declines sharply with the diafiltration volume, whereas for mercury it is the contrary.

  4. Characterization of hydroxybenzoic acid chelating resins: equilibrium, kinetics, and isotherm profiles for Cd(II and Pb(II uptake

    Directory of Open Access Journals (Sweden)

    BHAVNA A. SHAH

    2011-06-01

    Full Text Available Chelating ion-exchange resins were synthesized by polycondensation of ortho/para hydroxybenzoic acid with resorcinol/catechol employing formaldehyde as cross-linking agent at 80±5 °C in DMF. The resins were characterized by FTIR and XRD. The uptake behaviour of synthesized resins for Cd(II and Pb(II ions have been studied depending on contact time, pH, metal ion concentration and temperature. The sorption data obtained at optimized conditions were analyzed by the Langmuir and Freundlich isotherms. Experimental data of all metal–resin system were best represented by the Freundlich isotherm. The maximum obtained sorption capacity for cadmium was 69.53 mg g-1 and 169.32 mg g-1 for Lead. The adsorption process follows first order kinetics and the specific rate constant Kr was obtained by the application of the Lagergan equation. Thermodynamic parameters ∆Gads, ∆Sads and ∆Hads were calculated for the metal–resin systems. The external diffusion rate constant (KS and the intra-particle diffusion rate constant (Kid were calculated by the Spahn–Schlunder and Weber–Morris models, respectively. The sorption process was found to follow an intra-particle diffusion phenomenon.

  5. Synthesis of a novel heptacoordinated Fe(III) dinuclear complex: experimental and theoretical study of the magnetic properties.

    Science.gov (United States)

    Craig, Gavin A; Barrios, Leoní A; Sánchez Costa, José; Roubeau, Olivier; Ruiz, Eliseo; Teat, Simon J; Wilson, Chick C; Thomas, Lynne; Aromí, Guillem

    2010-05-28

    A new functionalized bis-pyrazol-pyridine ligand has been prepared by reaction with hydrazine of the corresponding bis-β-diketone precursor, also unprecedented. The aerobic reaction of this ligand with ferrous thiocyanate in the presence of ascorbic or oxalic acid affords the dinuclear complex of seven-coordinate Fe(III), [Fe₂(H₄L2)₂(ox)(NCS)₄] (1), as revealed by single crystal X-ray diffraction. This may represent an entry into a new family of [Fe₂] compounds with heptacoordinate metal centres. The capacity of this unusual chromophore to undergo magnetic super-exchange was investigated by means of bulk magnetization and DFT calculations. Both approaches confirmed the presence of antiferromagnetic interactions within the molecule. The theoretical investigation has served to describe the magnetic orbitals of Fe(III) in this unusual coordination geometry, as well as the exchange mechanism. A brief review of the scarce number of iron heptacoordinate complexes reported in the literature is also included and discussed.

  6. Interaction of Imidazole Containing Hydroxamic Acids with Fe(III: Hydroxamate Versus Imidazole Coordination of the Ligands

    Directory of Open Access Journals (Sweden)

    Etelka Farkas

    2007-01-01

    Full Text Available Solution equilibrium studies on Fe(III complexes formed with imidazole-4-carbohydroxamic acid (Im-4-Cha, N-Me-imidazole-4-carbohydroxamic acid (N-Me-Im-4-Cha, imidazole-4-acetohydroxamic acid (Im-4-Aha, and histidinehydroxamic acid (Hisha have been performed by using pH-potentiometry, UV-visible spectrophotometry, EPR, ESI-MS, and H-NMR methods. All of the obtained results demonstrate that the imidazole moiety is able to play an important role very often in the interaction with Fe(III, even if this metal ion prefers the hydroxamate chelates very much. If the imidazole moiety is in α-position to the hydroxamic one (Im-4-Cha and N-Me-Im-4-Cha its coordination to the metal ion is indicated unambiguously by our results. Interestingly, parallel formation of (Nimidazole, Ohydroxamate, and (Ohydroxamate, Ohydroxamate type chelates seems probable with N-Me-Im-4-Cha. The imidazole is in β-position to the hydroxamic moiety in Im-4-Aha and an intermolecular noncovalent (mainly H-bonding interaction seems to organize the intermediate-protonated molecules in this system. Following the formation of mono- and bishydroxamato mononuclear complexes, only EPR silent species exists in the Fe(III-Hisha system above pH 4, what suggests the rather significant “assembler activity” of the imidazole (perhaps together with the ammonium moiety.

  7. Interaction of imidazole containing hydroxamic acids with Fe(III): hydroxamate versus imidazole coordination of the ligands.

    Science.gov (United States)

    Farkas, Etelka; Bátka, Dávid; Csóka, Hajnalka; Nagy, Nóra V

    2007-01-01

    Solution equilibrium studies on Fe(III) complexes formed with imidazole-4-carbohydroxamic acid (Im-4-Cha), N-Me-imidazole-4-carbohydroxamic acid (N-Me-Im-4-Cha), imidazole-4-acetohydroxamic acid (Im-4-Aha), and histidinehydroxamic acid (Hisha) have been performed by using pH-potentiometry, UV-visible spectrophotometry, EPR, ESI-MS, and H1-NMR methods. All of the obtained results demonstrate that the imidazole moiety is able to play an important role very often in the interaction with Fe(III), even if this metal ion prefers the hydroxamate chelates very much. If the imidazole moiety is in alpha-position to the hydroxamic one (Im-4-Cha and N-Me-Im-4-Cha) its coordination to the metal ion is indicated unambiguously by our results. Interestingly, parallel formation of (Nimidazole, Ohydroxamate), and (Ohydroxamate, Ohydroxamate) type chelates seems probable with N-Me-Im-4-Cha. The imidazole is in beta-position to the hydroxamic moiety in Im-4-Aha and an intermolecular noncovalent (mainly H-bonding) interaction seems to organize the intermediate-protonated molecules in this system. Following the formation of mono- and bishydroxamato mononuclear complexes, only EPR silent species exists in the Fe(III)-Hisha system above pH 4, what suggests the rather significant "assembler activity" of the imidazole (perhaps together with the ammonium moiety).

  8. Characterization and Properties of Activated Carbon Prepared from Tamarind Seeds by KOH Activation for Fe(III) Adsorption from Aqueous Solution.

    Science.gov (United States)

    Mopoung, Sumrit; Moonsri, Phansiri; Palas, Wanwimon; Khumpai, Sataporn

    2015-01-01

    This research studies the characterization of activated carbon from tamarind seed with KOH activation. The effects of 0.5 : 1-1.5 : 1 KOH : tamarind seed charcoal ratios and 500-700°C activation temperatures were studied. FTIR, SEM-EDS, XRD, and BET were used to characterize tamarind seed and the activated carbon prepared from them. Proximate analysis, percent yield, iodine number, methylene blue number, and preliminary test of Fe(III) adsorption were also studied. Fe(III) adsorption was carried out by 30 mL column with 5-20 ppm Fe(III) initial concentrations. The percent yield of activated carbon prepared from tamarind seed with KOH activation decreased with increasing activation temperature and impregnation ratios, which were in the range from 54.09 to 82.03 wt%. The surface functional groups of activated carbon are O-H, C=O, C-O, -CO3, C-H, and Si-H. The XRD result showed high crystallinity coming from a potassium compound in the activated carbon. The main elements found in the activated carbon by EDS are C, O, Si, and K. The results of iodine and methylene blue adsorption indicate that the pore size of the activated carbon is mostly in the range of mesopore and macropore. The average BET pore size and BET surface area of activated carbon are 67.9764 Å and 2.7167 m(2)/g, respectively. Finally, the tamarind seed based activated carbon produced with 500°C activation temperature and 1.0 : 1 KOH : tamarind seed charcoal ratio was used for Fe(III) adsorption test. It was shown that Fe(III) was adsorbed in alkaline conditions and adsorption increased with increasing Fe(III) initial concentration from 5 to 20 ppm with capacity adsorption of 0.0069-0.019 mg/g.

  9. A new ion-selective electrode based on aluminium tungstate for Fe(III) determination in rock sample, pharmaceutical sample and water sample

    Indian Academy of Sciences (India)

    Mu Naushad

    2008-12-01

    An inorganic cation exchanger, aluminum tungstate (AT), has been synthesized by adding 0.1 M sodium tungstate gradually into 0.1 M aluminium nitrate at pH 1.2 with continuous stirring. The ion exchange capacity for Na+ ion and distribution coefficients of various metal ions was determined on the column of aluminium tungstate. The distribution studies of various metal ions showed the selectivity of Fe(III) ions by this cation exchange material. So, a Fe(III) ion-selective membrane electrode was prepared by using this cation exchange material as an electroactive material. The effect of plasticizers viz. dibutyl phthalate (DBP), dioctylphthalate (DOP), di-(butyl) butyl phosphate (DBBP) and tris-(2-ethylhexylphosphate) (TEHP), has also been studied on the performance of membrane sensor. It was observed that the membrane containing the composition AT: PVC: DBP in the ratio 2 : 20 : 15 displayed a useful analytical response with excellent reproducibility, low detection limit, wide working pH range (1–3.5), quick response time (15 s) and applicability over a wide concentration range of Fe(III) ions from 1 × 10-7 M to 1 × 10-1 M with a slope of 20 ± 1 mV per decade. The selectivity coefficients were determined by the mixed solution method and revealed that the electrode was selective for Fe(III) ions in the presence of interfering ions. The electrode was used for atleast 5 months without any considerable divergence in response characteristics. The constructed sensor was used as indicator electrode in the potentiometric titration of Fe(III) ions against EDTA and Fe(III) determination in rock sample, pharmaceutical sample and water sample. The results are found to be in good agreement with those obtained by using conventional methods.

  10. Humic substance-mediated Fe(III) reduction by a fermenting Bacillus strain from the alkaline gut of a humus-feeding scarab beetle larva.

    Science.gov (United States)

    Hobbie, Sven N; Li, Xiangzhen; Basen, Mirko; Stingl, Ulrich; Brune, Andreas

    2012-06-01

    Humus-feeding macroinvertebrates play an important role in the transformation of soil organic matter. Their diet contains significant amounts of redox-active components such as iron minerals and humic substances. In soil-feeding termites, acid-soluble Fe(III) and humic acids are almost completely reduced during gut passage. Here, we show that the reduction of Fe(III) and humic acids takes place also in the alkaline guts of scarab beetle larvae. Sterilized gut homogenates of Pachnoda ephippiata no longer converted Fe(III) to Fe(II), indicating an essential role of the gut microbiota in the process. From Fe(III)-reducing enrichment cultures inoculated with highly diluted gut homogenates, we isolated several facultatively anaerobic, alkali-tolerant bacteria that were closely related to metal-reducing isolates in the Bacillus thioparans group. Strain PeC11 showed a remarkable capacity for dissimilatory Fe(III) reduction, both at pH 7 and 10. Rates were strongly stimulated by the addition of the redox mediator 2,6-antraquinone disulfonate and by redox-active components in the fulvic-acid fraction of humus. Although the contribution of strain PeC11 to intestinal Fe(III) reduction in P. ephippiata remains to be further elucidated, our results corroborate the hypothesis that the lack of oxygen and the solubilization of humic substances in the extremely alkaline guts of humivorous soil fauna provide favorable conditions for the efficient reduction of Fe(III) and humic substances by a primarily fermentative microbiota.

  11. Characterization and Properties of Activated Carbon Prepared from Tamarind Seeds by KOH Activation for Fe(III) Adsorption from Aqueous Solution

    OpenAIRE

    Sumrit Mopoung; Phansiri Moonsri; Wanwimon Palas; Sataporn Khumpai

    2015-01-01

    This research studies the characterization of activated carbon from tamarind seed with KOH activation. The effects of 0.5 : 1–1.5 : 1 KOH : tamarind seed charcoal ratios and 500–700°C activation temperatures were studied. FTIR, SEM-EDS, XRD, and BET were used to characterize tamarind seed and the activated carbon prepared from them. Proximate analysis, percent yield, iodine number, methylene blue number, and preliminary test of Fe(III) adsorption were also studied. Fe(III) adsorption was carr...

  12. Complex Formation in a Liquid-Liquid Extraction System Containing Co(II), 4-(2-Thiazolylazo)resorcinol and Monotetrazolium Salt.

    Science.gov (United States)

    Divarova, Vidka; Stojnova, Kirila; Racheva, Petya; Lekova, Vanya

    2016-01-01

    The ion-associated complex formed between anionic chelate of Co(II)-4-(2-Thiazolylazo)resorcinol (TAR) with the monotetrazolium cation of 2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (INT) in the liquid-liquid extraction system Co(II)-TAR-INT-H(2)O-CHCl(3) was studied by the spectrophotometric method. The optimum extraction conditions of Co(II) were found. The extraction equilibria were studied. The equilibrium constants, the recovery factor and some analytical characteristics were calculated. The validity of Beer's law was checked. The molar ratio of the components in the ternary ion-associated complex Co(II)-TAR-INT was determined. The general formula of the complex was suggested. The effect of various foreign ions and reagents on the process of complex formation in the liquid-liquid extraction system was studied.

  13. Rational design of two bpy-bridged 3D and 2D Co(II) open frameworks with similar amino-acid-based Schiff bases.

    Science.gov (United States)

    Li, Zong-Ze; Du, Lin; Zhou, Jie; Zhu, Ming-Rong; Qian, Fen-Hua; Liu, Jing; Chen, Peng; Zhao, Qi-Hua

    2012-12-21

    Two novel bpy-bridged Co(II) Schiff base complexes have been synthesized by the hydro(solvo)thermal reactions of corresponding amino-acid-based Schiff bases, bpy and Co(NO(3))(2)·6H(2)O. The following formulae identify the two complexes: {[Co(napala)(bpy)(0.5)]·H(2)O}(n) (1) and [Co(napgly)(bpy)(0.5)](n) (2) [H(2)napala = N-(2-hydroxy-1-naphthylmethylidene)-D/L-alanine, H(2)napgly = N-(2-hydroxy-1-naphthylmethylidene)-glycine and bpy = 4,4'-bipyridine]. These two compounds have been characterized using single-crystal X-ray diffraction, infrared, powder X-ray diffraction, thermogravimetric analysis, optical spectra analysis, and magnetic measurement. Complex 1 features an unprecedented threefold interpenetrated diamond network based on the fan-shaped Co(II)(4)(μ(2)-napala)(4) molecular square node and bpy linker, which represents the first example of 3D framework among the amino-acid-based Schiff base complexes with salicylaldehyde or its derivatives. In 2, adjacent Co(II) ions are bridged by μ(2)-napgly(2-) to form left- and right-handed [Co(II)(μ(2)-napgly)](n) helical chains. These two types of helical chains are sustained alternately by a symmetrical bpy co-ligand into a 2D grid-based layer. The solid-state fluorescence of complexes 1 and 2 are quenched almost completely compared with free mixed-ligands at room temperature. Moreover, magnetic studies show the dominant antiferromagnetic coupling between the Co(II) centers mediated by the syn-anti-COO(-)-bridges in both complexes.

  14. Removal of Co(II), Cu(II) and Pb(II) ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies

    OpenAIRE

    Omid Moradi; Behrooz Mirza; Mehdi Norouzi; Ali Fakhri

    2012-01-01

    Abstract Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II), Cu(II) and Pb(II) by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlatio...

  15. Removal of Co(II, Cu(II and Pb(II ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies

    Directory of Open Access Journals (Sweden)

    Moradi Omid

    2012-12-01

    Full Text Available Abstract Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II, Cu(II and Pb(II by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlich isotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be 0.7388, 0.8396 and 3.0367 mg/g for Co(II, Cu(ΙΙ and Pb(II ions and removal capacity of P(MMA-HEMA was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II, Cu(ΙΙ and Pb(II ions, respectively. Changes in the standard Gibbs free energy (ΔG0, standard enthalpy (ΔH0 and standard entropy (ΔS0 showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA are spontaneous and exothermic at 293–323 K. The maximum desorption efficiency was 75.26% for Pb(II using 0.100 M HNO3, 70.10% for Cu(II using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II.

  16. Removal of Co(II, Cu(II and Pb(II Ions by Polymer Based 2-Hydroxyethyl Methacrylate:Thermodynamics and Desorption Studies

    Directory of Open Access Journals (Sweden)

    Omid Moradi

    2012-12-01

    Full Text Available Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II, Cu(II and Pb(II by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms wereobtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlichisotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be0.7388, 0.8396 and 3.0367 mg/g for Co(II, Cu(ΙΙ and Pb(II ions and removal capacity of P(MMA-HEMA was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II, Cu(ΙΙ and Pb(II ions, respectively. Changes in the standard Gibbs free energy (ΔG0, standard enthalpy (ΔH0 and standard entropy (ΔS0 showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA are spontaneous and exothermic at 293–323 K. The maximum desorption efficiency was 75.26% for Pb(II using 0.100 M HNO3, 70.10% for Cu(II using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II.

  17. Probing the redox non-innocence of dinuclear, three-coordinate Co(II) nindigo complexes: not simply β-diketiminate variants.

    Science.gov (United States)

    Fortier, Skye; González-del Moral, Octavio; Chen, Chun-Hsing; Pink, Maren; Le Roy, Jennifer J; Murugesu, Muralee; Mindiola, Daniel J; Caulton, Kenneth G

    2012-11-21

    Reduction of the dinuclear Co(II) nindigo complex dmp(2)Nin[Co(N{SiMe(3)}(2))](2), with 1 or 2 equiv. of K(0) (or KC(8)), affords the reduced complexes [dmp(2)Nin{Co(N{SiMe(3)}(2))}(2)](-) and [dmp(2)Nin{Co(N{SiMe(3)}(2))}(2)](2-), respectively. Inspection of these reduced species reveals ligand-centered reduction, with each cobalt ion retaining a formal 2+ oxidation state.

  18. Removal of Co(II), Cu(II) and Pb(II) ions by polymer based 2-hydroxyethyl methacrylate: thermodynamics and desorption studies.

    Science.gov (United States)

    Moradi, Omid; Mirza, Behrooz; Norouzi, Mehdi; Fakhri, Ali

    2012-12-22

    Removal thermodynamics and desorption studies of some heavy metal ions such as Co(II), Cu(II) and Pb(II) by polymeric surfaces such as poly 2-hydroxyethyl methacrylate (PHEMA) and copolymer 2-hydroxyethyl methacrylate with monomer methyl methacrylate P(MMA-HEMA) as adsorbent surfaces from aqueous single solution were investigated with respect to the changes in pH of solution, adsorbent composition, contact time and temperature in the individual aqueous solution. The linear correlation coefficients of Langmuir and Freundlich isotherms were obtained and the results revealed that the Langmuir isotherm fitted the experiment results better than Freundlich isotherm. Using the Langmuir model equation, the monolayer removal capacity of PHEMA surface was found to be 0.7388, 0.8396 and 3.0367 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions and removal capacity of P(MMA-HEMA) was found to be 28.8442, 31.1526 and 31.4465 mg/g for Co(II), Cu(ΙΙ) and Pb(II) ions, respectively. Changes in the standard Gibbs free energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) showed that the removals of mentioned ions onto PHEMA and P(MMA-HEMA) are spontaneous and exothermic at 293-323 K. The maximum desorption efficiency was 75.26% for Pb(II) using 0.100 M HNO3, 70.10% for Cu(II) using 0.100 M HCl, 59.20% for 0.100 M HCl 63.67% Co(II).

  19. Physicochemical properties of 3,4,5-trimethoxybenzoates of Mn(II, Co(II, Ni(II and Zn(II

    Directory of Open Access Journals (Sweden)

    W. FERENC

    2005-09-01

    Full Text Available The complexes of Mn(II, Co(II, Ni(II, Cu(II and Zn(II with 3,4,5-trimethoxybenzoic acid anion of the formula: M(C10H11O52·nH2O, where n = 6 for Ni(II, n = 1 for Mn(II, Co(II, Cu(II, and n = 0 for Zn, have been synthesized and characterized by elemental analysis, IR spectroscopy, X–ray diffraction measurements, thermogravimetry and magnetic studies. They are crystalline compounds characterized by various symmetry. They decompose in various ways when heated in air to 1273 K. At first, they dehydrate in one step and form anhydrous salts. The final products of decomposition are oxides of the respective metals (Mn2O3, Co3O4, NiO, CuO, ZnO. The solubilities of the analysed complexes in water at 293 K are in the orders of 10-2 – 10-4 mol dm-3. The magnetic susceptibilities of the Mn(II, Co(II, Ni(II and Cu(II complexes were measured over the range of 76–303 K and the magnetic moments were calculated. The results show that the 3,4,5-trimethoxybenzoates of Mn(II, Co(II and Ni(II are high-spin complexes but that of Cu(II forms a dimer [Cu2(C10H11O54(H2O2]. The carboxylate groups bind as monodentate or bidentate chelating or bridging ligands.

  20. Potentiometric study of atenolol as hypertension drug with Co(II, Ni(II, Cu(II and Zn(II transition metal ions in aqueous solution

    Directory of Open Access Journals (Sweden)

    Abdulbaset A. Zaid

    2015-01-01

    Full Text Available Binary and ternary complexes of Co(II, Ni(II, Cu(II and Zn(II with atenolol as hypertension drug and glycine have been determined pH metrically at room temperature and 0.01 M ionic strength (NaClO4 in aqueous solution. The formation of various possible species has been evaluated by computer program and discussed in terms of various relative stability parameters.

  1. Biosorption of Ni(II), Cr(III), and Co(II) from Solutions Using Acalypha hispida Leaf: Kinetics, Equilibrium, and Thermodynamics

    OpenAIRE

    Adesola Babarinde; J. Oyebamiji Babalola; John Adegoke; Osundeko, Adebola O.; Susan Olasehinde; Adetayo Omodehin; Emmanuel Nurhe

    2013-01-01

    Biosorption studies were conducted to study the removal of Ni(II), Cr(III), and Co(II) from aqueous solution of Acalypha hispida leaf. The FTIR spectral characteristics of Acalypha hispida leaf revealed the presence of ioniazable groups that could participate in the binding of metal ions in solution. The kinetic, equilibrium, and thermodynamic studies of the biosorption of the metal ions were investigated using various physicochemical parameters; each parameter was found to affect the biosorp...

  2. Modelling the magnetic behaviour of square-pyramidal Co(II)5 aggregates: tuning SMM behaviour through variations in the ligand shell.

    Science.gov (United States)

    Klöwer, Frederik; Lan, Yanhua; Nehrkorn, Joscha; Waldmann, Oliver; Anson, Christopher E; Powell, Annie K

    2009-07-27

    Three new mu4-bridged Co(II)5 clusters with similar core motifs have been synthesised with the use of N-tert-butyldiethanolamine (tbdeaH2) and pivalic acid (piv): [Co(II)5(mu4-N3)(tbdea)2(mu-piv)4(piv)(CH3CN)2].CH3CN (1), [Co(II)5(mu4-Cl)(Cl)(tbdea)2(mu-piv)4(pivH)2] (2) and [Co(II)5(mu4-N3)(Cl)(tbdea)2(mu-piv)4(pivH)2] (3). Magnetic measurements were performed for all three compounds. It was found that while the chloride-bridged cluster 2 does not show an out-of-phase signal, which excludes single-molecule magnet (SMM) behaviour, the azide-bridged compounds 1 and 3 show out-of-phase signals as well as frequency dependence of the ac susceptibility, as expected for SMMs. We confirmed that 1 is a SMM with zero-field quantum tunnelling of the magnetisation at 1.8 K. Compound 3 is likely a SMM with a blocking temperature well below 1.8 K. We established a physical model to fit the chiT versus T and M versus B curves of the three compounds to reproduce the observed SMM trend. The analysis showed that small changes in the ligand shell modify not only the magnitude of exchange constants, but also affect the J and g matrices in a non-trivial way.

  3. Microwave Synthesis, Spectral, Thermal and Antimicrobial Studies of Some Co(II), Ni(II) and Cu(II) Complexes Containing 2-Aminothiazole Moiety

    OpenAIRE

    A. P. Mishra; H. Purwar; Rajendra K. Jain; S.K Gupta

    2012-01-01

    Some new Schiff base metal complexes of Co(II), Ni(II) and Cu(II) derived from 4-chlorobenzylidene-2-aminothiazole (CAT) and 2-nitrobenzylidene-2-aminothiazole (NAT) have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR, magnetic susceptibility, thermal, electrical conductivity and XRD analysis. The complexes are coloured and stable in air. Analytical data r...

  4. Selective divalent cobalt ions detection using Ag2O3-ZnO nanocones by ICP-OES method for environmental remediation.

    Directory of Open Access Journals (Sweden)

    Mohammed M Rahman

    Full Text Available Here, we have synthesized Ag2O3-ZnO nanocones (NCs by a wet-chemical route using reducing agents at low temperature. The structural, optical and morphological properties of Ag2O3-ZnO NCs were investigated by several conventional techniques such as powder XRD, XPS, FESEM, XEDS, FTIR and UV/vis. spectroscopy. The analytical parameters of prepared NCs were also calculated for a selective detection of divalent cobalt [Co(II] prior to its determination by inductively coupled plasma-optical emission spectrometry (ICP-OES. The selectivity of NCs toward various metal ions, including Cd(II, Co(II, Cr(III, Cu(II, Fe(III, Ni(II, and Zn(II was studied. Results of the selectivity study demonstrated that Ag2O3-ZnO NC phase was the most selective towards Co(II ion. The uptake capacity for Co(II ion was experimentally calculated to be ∼76.69 mgg-1. Moreover, adsorption isotherm data provided that the adsorption process was mainly monolayer on homogeneous adsorbent surfaces of Ag2O3-ZnO NCs. Kinetic study revealed that the adsorption of Co(II on Ag2O3-ZnO NCs phase followed the pseudo-second-order kinetic model. In addition, thermodynamic results provided that the adsorption mechanism of Co(II ions on Ag2O3-ZnO NCs was a spontaneous process and thermodynamically favorable. Finally, the proposed method was validated by applying it to real environmental water samples with reasonable results.

  5. Template Synthesis, Characterization and Biological Activity of Cu(II, Ni(II, Co(II, Zn(IIComplexes with Isonicotinoylhydrazone--2-aldehydefluorene Ligand

    Directory of Open Access Journals (Sweden)

    2010-01-01

    Full Text Available This is about synthesizing new complex combinations of Cu(II, Ni(II,Co(II, Zn(II with aroylhydrazone ligand isonicotinoylhydrazone-2-aldehydefluorene (INHAF made by condensation of isonicotinoylhydrazine with 2-aldehydefluorene. The complexes have been characterized by analytical data, IR, UV-Vis, NMR spectra, magnetic susceptibility values, thermal analysis and for the Cu(II complex the ESR spectrum has been registered. For all complexes the biological activity against the Staphylo-coccus aureus, Escherichia coli, Klebssiella pneumoniae bacteria has been investigated. The experimental data sustain stoichiometry of 1:2 (metal/ligand for the Cu(II, Ni(II, Zn(II complexes and of 1:1 for the complex with Co(II. The electronic spectra and the magnetic moments suggest octahedral stereochemistry at the complexes with Cu(II, Ni(II and the tetrahedral geometry for the Co(II complex. The INHAF ligand is coordinated bidentate by the O=C amide oxygen and the azomethine nitrogen in the complexes of Cu(II, Ni(II, Co(II and monodentate by the azomethine nitrogen in the complex of Zn(II.

  6. Synthesis, Characterization and Antimicrobial Studies of N1-[(1E-1-(2-Hydroxyphenyl ethylidene]-2-oxo-2H-chromene-3-carbohydrazide and its Metal Complexes

    Directory of Open Access Journals (Sweden)

    K. Siddappa

    2009-01-01

    Full Text Available A new complexes of the type ML, MʹL and M″L [where M=Cu(II, Co(II, Ni(II and Mn(II, Mʹ=Fe(III and M″=Zn(II, Cd(II and Hg(II and L=N1-[(1E-1-(2-hydroxyphenylethylidene]-2-oxo-2H-chromene- 3-carbohydrazide (HL] Schiff base have been synthesized and characterized by elemental analysis, magnetic susceptibility, molar conductance, IR, 1H NMR, UV-Visible and ESR data. The studies indicate the HL acts as doubly monodentate bridge for metal ions and form mononuclear complexes. The complexes Ni(II, Co(II, Cu(II Mn(II and Fe(III complexes are found to be octahedral, where as Zn(II, Cd(II and Hg(II complexes are four coordinated with tetrahedral geometry. The synthesized ligand and its metal complexes were screened for their antimicrobial activity.

  7. Preparation of cross-linked magnetic chitosan-phenylthiourea resin for adsorption of Hg(II), Cd(II) and Zn(II) ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Monier, M., E-mail: monierchem@yahoo.com [Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Abdel-Latif, D.A. [Chemistry Department, Faculty of Science, Mansoura University, Mansoura (Egypt)

    2012-03-30

    Highlights: Black-Right-Pointing-Pointer Chitosan was chemically modified through the reaction with phenylisothiocyanate. Black-Right-Pointing-Pointer The modified chitosan-phenylthiourea cross-linked with formaldehyde in presence of magnetite to produce modified magnetic resin. Black-Right-Pointing-Pointer The resulted resin characterized by various instrumental methods. Black-Right-Pointing-Pointer The resin was applied to remove Hg{sup 2+}, Cd{sup 2+} and Zn{sup 2+} from aqueous solutions. - Abstract: In this study, cross-linked magnetic chitosan-phenylthiourea (CSTU) resin were prepared and characterized by means of FTIR, {sup 1}H NMR, SEM high-angle X-ray diffraction (XRD), magnetic properties and thermogravimetric analysis (TGA). The prepared resin were used to investigate the adsorption properties of Hg(II), Cd(II) and Zn(II) metal ions in an aqueous solution. The extent of adsorption was investigated as a function of pH and the metal ion removal reached maximum at pH 5.0. Also, the kinetic and thermodynamic parameters of the adsorption process were estimated. These data indicated that the adsorption process is exothermic and followed the pseudo-second-order kinetics. Equilibrium studies showed that the data of Hg(II), Cd(II) and Zn(II) adsorption followed the Langmuir model. The maximum adsorption capacities for Hg(II), Cd(II) and Zn(II) were estimated to be 135 {+-} 3, 120 {+-} 1 and 52 {+-} 1 mg/g, which demonstrated the high adsorption efficiency of CSTU toward the studied metal ions.

  8. Synthesis and studies on Cu(II), Co(II), Ni(II) complexes of Knoevenagel β-diketone ligands

    Science.gov (United States)

    Sumathi, S.; Tharmaraj, P.; Sheela, C. D.; Anitha, C.

    2012-11-01

    Transition metal complexes of various acetylacetone based ligands of the type ML [where M = Cu(II), Ni(II), Co(II); L = 3-(aryl)-pentane-2,4-dione] have been synthesized. The structural features have been derived from their elemental analysis, magnetic susceptibility, molar conductance, IR, UV-Vis, 1H NMR, Mass and ESR spectral studies. Conductivity measurements reveal that all the complexes are non-electrolytic in nature. Spectroscopic and other analytical data of the complexes suggest octahedral geometry for other metal(II) complexes. The redox behavior of the copper(II) complexes have been studied by cyclic voltammetry. The free ligands and their metal complexes have been screened for their in vitro biological activities against the bacteria Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus as well as the fungus Candida albicans by well diffusion method. The zone of inhibition value indicates that the most of the metal(II) complexes are found to possess increased activities compared to those of the free ligands. All synthesized compounds may serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic generation (SHG) efficiency of the ligands (L1-L3) was found to be considerable effect than that of urea and KDP (potassium dihydrogen phosphate).

  9. Multireference ab initio studies of zero-field splitting and magnetic circular dichroism spectra of tetrahedral Co(II) complexes.

    Science.gov (United States)

    Sundararajan, Mahesh; Ganyushin, Dmitry; Ye, Shengfa; Neese, Frank

    2009-08-14

    A newly developed multireference (MR) ab initio method for the calculation of magnetic circular dichroism (MCD) spectra was calibrated through the calculation of the ground- and excited state properties of seven high-spin (S = 3/2) Co(II) complexes. The MCD spectra were computed by the explicit treatment of spin-orbit coupled (SOC) and spin-spin coupled (SSC) N-electron states. For the complexes studied in this work, we found that the SOC is more important than the SSC for determining the ground state zero field splitting (ZFS). Our computed ZFS parameter D for the [Co(PPh(3))(2)Cl(2)] model complex is -17.6 cm(-1), which is reasonably close to the experimental value of -14.8 cm(-1). Generally, the computed absorption and MCD spectra are in fair agreement with experiment for all investigated complexes. Thus, reliable electronic structure and spectroscopic predictions for medium sized transition metal complexes are feasible on the basis of this methodology. This characterizes the presented method as a promising tool for MCD spectra interpretations of transition metal complexes in a variety of areas of chemistry and biology.

  10. Sensitive spectrophotometric determination of Co(II) using dispersive liquid-liquid micro-extraction method in soil samples.

    Science.gov (United States)

    Hasanpour, Foroozan; Hadadzadeh, Hassan; Taei, Masoumeh; Nekouei, Mohsen; Mozafari, Elmira

    2016-05-01

    Analytical performance of conventional spectrophotometer was developed by coupling of effective dispersive liquid-liquid micro-extraction method with spectrophotometric determination for ultra-trace determination of cobalt. The method was based on the formation of Co(II)-alpha-benzoin oxime complex and its extraction using a dispersive liquid-liquid micro-extraction technique. During the present work, several important variables such as pH, ligand concentration, amount and type of dispersive, and extracting solvent were optimized. It was found that the crucial factor for the Co(II)-alpha benzoin oxime complex formation is the pH of the alkaline alcoholic medium. Under the optimized condition, the calibration graph was linear in the ranges of 1.0-110 μg L(-1) with the detection limit (S/N = 3) of 0.5 μg L(-1). The preconcentration operation of 25 mL of sample gave enhancement factor of 75. The proposed method was applied for determination of Co(II) in soil samples.

  11. Structure, magnetism, and theoretical study of a mixed-valence Co(II)3Co(III)4 heptanuclear wheel: lack of SMM behavior despite negative magnetic anisotropy.

    Science.gov (United States)

    Chibotaru, Liviu F; Ungur, Liviu; Aronica, Christophe; Elmoll, Hani; Pilet, Guillaume; Luneau, Dominique

    2008-09-17

    A mixed-valence Co(II)/Co(III) heptanuclear wheel [Co(II)3Co(III)4(L)6(MeO)6] (LH2 = 1,1,1-trifluoro-7-hydroxy-4-methyl-5-aza-hept-3-en-2-one) has been synthesized and its crystal structure determined using single-crystal X-ray diffraction. The valence state of each cobalt ion was established by bond valence sum calculations. Studies of the temperature dependence of the magnetic susceptibility and the field dependence of the magnetization evidence ferromagnetic interactions within the compound. In order to understand the magnetic properties of this Co7 wheel, we performed ab initio calculations for each cobalt fragment at the CASSCF/CASPT2 level, including spin-orbit coupling effects within the SO-RASSI approach. The four Co(III) ions were found to be diamagnetic and to give a significant temperature-independent paramagnetic contribution to the susceptibility. The spin-orbit coupling on the three Co(II) sites leads to separations of approximately 200 cm(-1) between the ground and excited Kramers doublets, placing the Co7 wheel into a weak-exchange limit in which the lowest electronic states are adequately described by the anisotropic exchange interaction between the lowest Kramers doublets on Co(II) sites. Simulation of the exchange interaction was done within the Lines model, keeping the fully ab initio treatment of magnetic anisotropy effects on individual cobalt fragments using a recently developed methodology. A good description of the susceptibility and magnetization was obtained for nearest-neighbor (J1) and next-nearest-neighbor (J2) exchange parameters (1.5 and 5.5 cm(-1), respectively). The strong ferromagnetic interaction between distant cobalt ions arises as a result of low electron-promotion energies in the exchange bridges containing Co(III) ions. The calculations showed a large value of the magnetization along the main magnetic axis (10.1 mu(B)), which is a combined effect of the ferromagnetic exchange interaction and negative magnetic anisotropy on

  12. Diverse CdII coordination complexes derived from bromide isophthalic acid binding with auxiliary N-donor ligands

    Science.gov (United States)

    Tang, Meng; Dong, Bao-Xia; Wu, Yi-Chen; Yang, Fang; Liu, Wen-Long; Teng, Yun-Lei

    2016-12-01

    The coordination characteristics of 4-bromoisophthalic acid (4-Br-H2ip) have been investigated in a series of CdII-based frameworks. Hydrothermal reactions of CdII salts and 4-Br-H2ip together with flexible or semiflexible N-donor auxiliary ligands resulted in the formation of four three-dimensional coordination complexes with diverse structures: {Cd(bix)0.5(bix)0.5(4-Br-ip)]·H2O}n (1), [Cd(bbi)0.5(bbi)0.5(4-Br-ip)]n (2), {[Cd(btx)0.5(4-Br-ip)(H2O)]·0.5CH3OH·H2O}n (3) and {[Cd(bbt)0.5(4-Br-ip)(H2O)]·3·5H2O}n (4). These compounds were characterized by elemental analyses, IR spectra, single-crystal and powder X-ray diffraction. They displayed diverse structures depending on the configuration of the 4-connected metal node, the coordination mode of the 4-Br-H2ip, the coordination ability and conformationally flexibility of the N-donor auxiliary. Compound 1 exhibits 3-fold interpenetrated 66 topology and compound 2 has a 412 topology. Compounds 3-4 have similar 3D pillar-layered structures based on 3,4-connected binodal net with the Schläfli symbol of (4·38). The thermal stabilities and photoluminescence properties of them were discussed in detail.

  13. Removal of Cd(II), Zn(II) and Pb(II) from aqueous solutions by brown marine macro algae: kinetic modelling

    OpenAIRE

    Freitas, Olga; Martins, Ramiro; Matos, Cristina; Boaventura, Rui

    2008-01-01

    Specific marine macro algae species abundant at the Portuguese coast (Laminaria hiperborea, Bifurcaria bifurcata, Sargassum muticum and Fucus spiralis) were shown to be effective for removing toxic metals (Cd(II), Zn(II) and Pb(II)) from aqueous solutions. The initial metal concentrations in solution were about 75-100 mg L-1. The observed biosorption capacities for cadmium, zinc and lead ions were in the ranges of 23.9-39.5 mg g-1, 18.6-32.0 mg g-1 and 32.3-50.4 mg g-1, respectively. Kinetic ...

  14. [Biosorption of Cd(II), Cu(II), Pb(II) and Zn(II) in aqueous solutions by fruiting bodies of macrofungi (Auricularia polytricha and Tremella fuciformis)].

    Science.gov (United States)

    Mo, Yu; Pan, Rong; Huang, Hai-wei; Cao, Li-xiang; Zhang, Ren-duo

    2010-07-01

    Batch experiments were conducted to study the ability of fruiting bodies of Auricularia polytricha and Tremella fuciformis to adsorb Cd(II), Cu(II), Pb(II) and Zn(II) from aqueous solutions, including biosorption ability of the biomass to remove heavy metals from solutions with different concentrations, kinetics of adsorption, influence of co-cations, and biosorption affinity in multi-metalsystem. Results showed that in the solutions with individual metal, the maximum biosorption amounts of Cd(II), Cu(II), Pb(II), Zn(II) by A. polytricha were 18.91, 18.69, 20.33, 12.42 mg x g(-1), respectively, and the highest removal rates for all cases were more than 85%. The maximum biosorption amounts of Cd(II), Cu(II), Pb(II), Zn(II) by T. fuciformis were 19.98, 20.15, 19.16, 16.41 mg x g(-1), respectively, and highest removal rates for all cases were more than 75%. In the solutions with initial concentrations of 10, 50 and 100 mg x L(-1), the biosorption amounts increased but the removal rates decreased as the initial concentrations increasing. The pseudo-second-order reaction model described adsorption kinetics of heavy metal ions by fruiting bodies of A. polytricha and T. fuciformis better than the pseudo-first-order reaction model. In the solutions with multi metals, the biosorption amounts of heavy metals by two biosorbent were in the order of Ph(II) > Cd(II) > Cu(II) > Zn(II). The ions with more negative charges were preferential to be sorbed. The biosorption ability of A. polytricha was inhibited in multi-metal solutions. In multi-metal solutions, T. fuciformis sorbed a higher amount of Pb(II) but lower amounts of other three ions than that in the individual metal solutions. The results indicated that both fruiting bodies of A. polytricha and T. fuciformis were potential biosorbents.

  15. Nanowires, Capacitors, and Other Novel Outer-Surface Components Involved in Electron Transfer to Fe(III) Oxides in Geobacter Species

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek, R.

    2008-12-22

    The overall goal of this project was to better understand the mechanisms by which Geobacter species transfer electrons outside the cell onto Fe(III) oxides. The rationale for this study was that Geobacter species are often the predominant microorganisms involved in in situ uranium bioremediation and the growth and activity of the Geobacter species during bioremediation is primarily supported by electron transfer to Fe(III) oxides. These studies greatly expanded the understanding of electron transfer to Fe(III). Novel concepts developed included the potential role of microbial nanowires for long range electron transfer in Geobacter species and the importance of extracytoplasmic cytochromes functioning as capacitors to permit continued electron transfer during the hunt for Fe(III) oxide. Furthermore, these studies provided target sequences that were then used in other studies to tract the activity of Geobacter species in the subsurface through monitoring the abundance of gene transcripts of the target genes. A brief summary of the major accomplishments of the project is provided.

  16. A strictly anaerobic betaproteobacterium Georgfuchsia toluolica gen. nov., sp. nov. degrades aromatic compounds with Fe(III), Mn(IV) or nitrate as an electron acceptor

    NARCIS (Netherlands)

    Weelink, S.A.B.; Doesburg, van W.C.J.; Talarico Saia, F.; Rijpstra, I.; Smidt, H.; Röling, W.; Stams, A.J.M.

    2009-01-01

    A bacterium (strain G5G6) that grows anaerobically with toluene was isolated from a polluted aquifer (Banisveld, the Netherlands). The bacterium uses Fe(III), Mn(IV) and nitrate as terminal electron acceptors for growth on aromatic compounds. The bacterium does not grow on sugars, lactate or acetate

  17. The Nature of the intermediates in the reactions of Fe(III)- and Mn(III)-microperoxidase-8 with H2O2 : a rapid kinetic study

    NARCIS (Netherlands)

    Primus, J.L.; Grunenwald, S.; Hagedoorn, P.L.; Albrecht-Gary, A.M.; Mandon, D.; Veeger, C.

    2002-01-01

    Kinetic studies were performed with microperoxidase-8 (Fe(III)MP-8), the proteolytic breakdown product of horse heart cytochrome c containing an octapeptide linked to an iron protoporphyrin IX. Mn(III) was substituted for Fe(III) in Mn(III)MP-8.The mechanism of formation of the reactive metal-oxo an

  18. Redox cycling of Fe(II) and Fe(III) in magnetite by Fe-metabolizing bacteria

    Science.gov (United States)

    Byrne, James M.; Klueglein, Nicole; Pearce, Carolyn; Rosso, Kevin M.; Appel, Erwin; Kappler, Andreas

    2015-03-01

    Microorganisms are a primary control on the redox-induced cycling of iron in the environment. Despite the ability of bacteria to grow using both Fe(II) and Fe(III) bound in solid-phase iron minerals, it is currently unknown whether changing environmental conditions enable the sharing of electrons in mixed-valent iron oxides between bacteria with different metabolisms. We show through magnetic and spectroscopic measurements that the phototrophic Fe(II)-oxidizing bacterium Rhodopseudomonas palustris TIE-1 oxidizes magnetite (Fe3O4) nanoparticles using light energy. This process is reversible in co-cultures by the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens. These results demonstrate that Fe ions bound in the highly crystalline mineral magnetite are bioavailable as electron sinks and electron sources under varying environmental conditions, effectively rendering magnetite a naturally occurring battery.

  19. Nanostructured Fe(III) catalysts for water oxidation assembled with the aid of organic acid salt electrolytes

    Science.gov (United States)

    Zhao, Qiang; Li, Dandan; Gao, Guofeng; Yuan, Wen; Hao, Genyan; Li, Jinping

    2016-11-01

    We describe the preparation of three partially ordered iron-based catalyst films (Fe-OAc, Fe-Pro, Fe-But) with nanoporous structure by electrodeposition from organate electrolytes containing Fe2+. The anions of the organic acids assisted the partial ordering of the nanostructured Fe(III) catalysts for water oxidation. A model involving an electrical double layer is invoked to explain the role of the organate electrolyte system in their formation. Analytical results have revealed the main component of the iron-based films to be a β-FeOOH structure. The Fe-But catalyst catalyzed water oxidation in 0.1 m potassium carbonate solution with an average activity of 1.48 mA cm-2 and an overpotential of 433 mV.

  20. Equilibrium Fe isotope fractionation between inorganic aqueous Fe(III) and the siderophore complex, Fe(III)-desferrioxamine B

    DEFF Research Database (Denmark)

    Dideriksen, Knud; Baker, Joel A.; Stipp, Susan Louise Svane

    2008-01-01

    In oxic oceans, most of the dissolved iron (Fe) exists as complexes with siderophore-like, strongly coordinating organic ligands. Thus, the isotope composition of the little amount of free inorganic Fe that is available for precipitation and preservation in the geological record may largely...... differently complexed Fe(III) pools were separated by addition of Na2CO3, which led to immediate precipitation of the inorganic Fe without causing significant dissociation of Fe-desferrioxamine complexes. Experiments using enriched 57Fe tracer showed that isotopic equilibration between the 57Fe......(III)-bearing environments, such as soils and rivers, and may, for example, largely control the Fe isotope composition of marine Fe–Mn crusts....

  1. Adsorption of Ni(II, Cu(II and Fe(III from Aqueous Solutions Using Activated Carbon

    Directory of Open Access Journals (Sweden)

    A. Edwin Vasu

    2008-01-01

    Full Text Available An activated carbon was tested for its ability to remove transition metal ions from aqueous solutions. Physical, Chemical and liquid-phase adsorption characterizations of the carbon were done following standard procedures. Studies on the removal of Ni(II, Cu(II and Fe(III ions were attempted by varying adsorbate dose, pH of the metal ion solution and time in batch mode. The equilibrium adsorption data were fitted with Freundlich, Langmuir and Redlich-Peterson isotherms and the isotherm constants were evaluated. Time variation studies indicate that adsorptions follow pseudo-second order kinetics. pH was found to have a significant role to play in the adsorption. The processes were endothermic and the thermodynamic parameters were evaluated. Desorption studies indicate that ion-exchange mechanism is operating.

  2. The role of multihaem cytochromes in the respiration of nitrite in Escherichia coli and Fe(III) in Shewanella oneidensis.

    Science.gov (United States)

    Clarke, Thomas A; Holley, Tracey; Hartshorne, Robert S; Fredrickson, Jim K; Zachara, John M; Shi, Liang; Richardson, David J

    2008-10-01

    The periplasmic nitrite reductase system from Escherichia coli and the extracellular Fe(III) reductase system from Shewanella oneidensis contain multihaem c-type cytochromes as electron carriers and terminal reductases. The position and orientation of the haem cofactors in multihaem cytochromes from different bacteria often show significant conservation despite different arrangements of the polypeptide chain. We propose that the decahaem cytochromes of the iron reductase system MtrA, MtrC and OmcA comprise pentahaem 'modules' similar to the electron donor protein, NrfB, from E. coli. To demonstrate this, we have isolated and characterized the N-terminal pentahaem module of MtrA by preparing a truncated form containing five covalently attached haems. UV-visible spectroscopy indicated that all five haems were low-spin, consistent with the presence of bis-His ligand co-ordination as found in full-length MtrA.

  3. Comparing the effects of Fe(III) and Cu(II) on the binding affinity of erlotinib to bovine serum albumin using spectroscopic methods

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yan [The State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Chen, Mingmao [Institute of Biomedical and Pharmaceutical Technology, Fuzhou University, Fuzhou, Fujian 350002 (China); Song, Ling, E-mail: songling@fjirsm.ac.cn [The State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2013-02-15

    The interactions between erlotinib (ET) and bovine serum albumin (BSA) in the absence and presence of Cu(II) and Fe(III) in aqueous solution were investigated by using fluorescence, circular dichroism and three-dimensional (3D) fluorescence spectroscopic methods under simulative physiological conditions. Erlotinib effectively quenched the intrinsic fluorescence of BSA with slight redshifts in the absence and presence of Cu(II) and Fe(III). Cu(II) decreased the binding affinity and reduced the binding sites of erlotinib to BSA, while Fe(III) increased the binding affinity and binding sites of erlotinib to BSA. The negative values of {Delta}H and {Delta}S illustrate that the binding is mainly driven by the hydrogen bond and van der Waals force. The conformation of BSA was changed through ET binding in the presence of Cu(II) and Fe(III), which was revealed by circular dichroism, synchronous fluorescence and 3D fluorescence spectroscopic methods. The results indicate that the binding capability of erlotinib to BSA is affected by the types of metal ions. Highlights: Black-Right-Pointing-Pointer Interaction of erlotinib (ET) with BSA in the presence of Cu(II) and Fe(III) was studied. Black-Right-Pointing-Pointer Using various spectroscopic methods such as UV, CD, fluorescence and three-dimensional (3D) fluorescence. Black-Right-Pointing-Pointer Effects of metal ions on the binding activity of ET to BSA have not been reported. Black-Right-Pointing-Pointer Ternary system Cu(II)/Fe(III)-ET-BSA induced the conformational change of BSA.

  4. The Geoglobus acetivorans genome: Fe(III) reduction, acetate utilization, autotrophic growth, and degradation of aromatic compounds in a hyperthermophilic archaeon.

    Science.gov (United States)

    Mardanov, Andrey V; Slododkina, Galina B; Slobodkin, Alexander I; Beletsky, Alexey V; Gavrilov, Sergey N; Kublanov, Ilya V; Bonch-Osmolovskaya, Elizaveta A; Skryabin, Konstantin G; Ravin, Nikolai V

    2015-02-01

    Geoglobus acetivorans is a hyperthermophilic anaerobic euryarchaeon of the order Archaeoglobales isolated from deep-sea hydrothermal vents. A unique physiological feature of the members of the genus Geoglobus is their obligate dependence on Fe(III) reduction, which plays an important role in the geochemistry of hydrothermal systems. The features of this organism and its complete 1,860,815-bp genome sequence are described in this report. Genome analysis revealed pathways enabling oxidation of molecular hydrogen, proteinaceous substrates, fatty acids, aromatic compounds, n-alkanes, and organic acids, including acetate, through anaerobic respiration linked to Fe(III) reduction. Consistent with the inability of G. acetivorans to grow on carbohydrates, the modified Embden-Meyerhof pathway encoded by the genome is incomplete. Autotrophic CO2 fixation is enabled by the Wood-Ljungdahl pathway. Reduction of insoluble poorly crystalline Fe(III) oxide depends on the transfer of electrons from the quinone pool to multiheme c-type cytochromes exposed on the cell surface. Direct contact of the cells and Fe(III) oxide particles could be facilitated by pilus-like appendages. Genome analysis indicated the presence of metabolic pathways for anaerobic degradation of aromatic compounds and n-alkanes, although an ability of G. acetivorans to grow on these substrates was not observed in laboratory experiments. Overall, our results suggest that Geoglobus species could play an important role in microbial communities of deep-sea hydrothermal vents as lithoautotrophic producers. An additional role as decomposers would close the biogeochemical cycle of carbon through complete mineralization of various organic compounds via Fe(III) respiration.

  5. Quantum Chemical Studies on the Prediction of Structures, Charge Distributions and Vibrational Spectra of Some Ni(II), Zn(II), and Cd(II) Iodide Complexes

    Science.gov (United States)

    Bardakci, Tayyibe; Kumru, Mustafa; Altun, Ahmet

    2016-06-01

    Transition metal complexes play an important role in coordination chemistry as well as in the formation of metal-based drugs. In order to obtain accurate results for studying these type of complexes quantum chemical studies are performed and especially density functional theory (DFT) has become a promising choice. This talk represents molecular structures, charge distributions and vibrational analysis of Ni(II), Zn(II), and Cd(II) iodide complexes of p-toluidine and m-toluidine by means of DFT. Stable structures of the ligands and the related complexes have been obtained in the gas phase at B3LYP/def2-TZVP level and calculations predict Ni(II) complexes as distorted polymeric octahedral whereas Zn(II) and Cd(II) complexes as distorted tetrahedral geometries. Charge distribution analysis have been performed by means of Mulliken, NBO and APT methods and physically most meaningful method for our compounds is explained. Vibrational spectra of the title compounds are computed from the optimized geometries and theoretical frequencies are compared with the previously obtained experimental data. Since coordination occurs via nitrogen atoms of the free ligands, N-H stretching bands of the ligands are shifted towards lower wavenumbers in the complexes whereas NH_2 wagging and twisting vibrations are shifted towards higher wavenumbers.

  6. Effect of Cu(II), Cd(II) and Zn(II) on Pb(II) biosorption by algae Gelidium-derived materials.

    Science.gov (United States)

    Vilar, Vítor J P; Botelho, Cidália M S; Boaventura, Rui A R

    2008-06-15

    Biosorption of Pb(II), Cu(II), Cd(II) and Zn(II) from binary metal solutions onto the algae Gelidium sesquipedale, an algal industrial waste and a waste-based composite material was investigated at pH 5.3, in a batch system. Binary Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II) solutions have been tested. For the same equilibrium concentrations of both metal ions (1 mmol l(-1)), approximately 66, 85 and 86% of the total uptake capacity of the biosorbents is taken by lead ions in the systems Pb(II)/Cu(II), Pb(II)/Cd(II) and Pb(II)/Zn(II), respectively. Two-metal results were fitted to a discrete and a continuous model, showing the inhibition of the primary metal biosorption by the co-cation. The model parameters suggest that Cd(II) and Zn(II) have the same decreasing effect on the Pb(II) uptake capacity. The uptake of Pb(II) was highly sensitive to the presence of Cu(II). From the discrete model it was possible to obtain the Langmuir affinity constant for Pb(II) biosorption. The presence of the co-cations decreases the apparent affinity of Pb(II). The experimental results were successfully fitted by the continuous model, at different pH values, for each biosorbent. The following sequence for the equilibrium affinity constants was found: Pb>Cu>Cd approximately Zn.

  7. Optimization of simultaneous electrochemical determination of Cd(II), Pb(II), Cu(II) and Hg(II) at carbon nanotube-modified graphite electrodes.

    Science.gov (United States)

    Pikna, L'ubomír; Heželová, Mária; Kováčová, Zuzana

    2015-01-01

    The health of the environment is worsening every day. Monitoring of potentially toxic elements and remediation of environmental pollution are necessary. Therefore, the research and development of simple, inexpensive, portable and effective sensors is important. Electrochemistry is a useful component of the field of environment monitoring. The present study focuses on evaluating and comparing three types of electrodes (PIGE, PIGE/MWCNT/HNO3 and PIGE/MWCNT/EDTA/HNO3) employed for the simultaneous electrochemical determination of four potentially toxic elements: Cd(II), Pb(II), Cu(II) and Hg(II). Cyclic voltammograms were measured in an acetate buffer. The LOD, LOQ, the standard and relative precisions of the method and a prediction intervals were calculated (according to the technical procedure DIN 32 645) for the three electrodes and for each measured element. The LOD for PIGE/CNT/HNO3 (the electrode with narrowest calculated prediction intervals) was 2.98 × 10(-7) mol L(-1) for Cd(II), 4.83 × 10(-7) mol L(-1) for Pb(II), 3.81 × 10(-7) mol L(-1) for Cu(II), 6.79 × 10(-7) mol L(-1) for Hg(II). One of the benefits of this study was the determination of the amount of Hg(II) in the mixture of other elements.

  8. Iminodiacetic acid functionalized cation exchange resin for adsorptive removal of Cr(VI), Cd(II), Ni(II) and Pb(II) from their aqueous solutions.

    Science.gov (United States)

    Misra, R K; Jain, S K; Khatri, P K

    2011-01-30

    Iminodiacetic acid functionality has been introduced on styrene-divinyl benzene co-polymeric beads and characterized by FT-IR in order to develop weak acid based cation exchange resin. This resin was evaluated for the removal of different heavy metal ions namely Cd(II), Cr(VI), Ni(II) and Pb(II) from their aqueous solutions. The results showed greater affinity of resin towards Cr(VI) for which 99.7% removal achieved in optimal conditions following the order Ni(II)>Pb(II)>Cd(II) with 65%, 59% and 28% removal. Experiments were also directed towards kinetic studies of adsorption and found to follow first order reversible kinetic model with the overall rate constants 0.3250, 0.2393, 0.4290 and 0.2968 for Cr(VI), Ni(II), Pb(II) and Cd(II) removal respectively. Detailed studies of Cr(VI) removal has been carried out to see the effect of pH, resin dose and metal ion concentration on adsorption and concluded that complexation enhanced the chromium removal efficacy of resin drastically, which is strongly pH dependent. The findings were also supported by the comparison of FT-IR spectra of neat resin with the chromium-adsorbed resin.

  9. Molecular phylogenetics and phylogeography of all the Saimiri taxa (Cebidae, Primates) inferred from mt COI and COII gene sequences.

    Science.gov (United States)

    Ruiz-García, Manuel; Luengas-Villamil, Kelly; Leguizamon, Norberto; de Thoisy, Benoit; Gálvez, Hugo

    2015-04-01

    Some previous genetic studies have been performed to resolve the molecular phylogenetics of the squirrel monkeys (Saimiri). However, these studies did not show consensus in how many taxa are within this genus and what the relationships among them are. For this reason, we sequenced 2,237 base pairs of the mt COI and COII genes in 218 Saimiri individuals. All, less 12 S. sciureus sciureus from French Guyana, were sampled in the wild. These samples represented all the living Saimiri taxa recognized. There were four main findings of this study. (1) Our analysis detected 17 different Saimiri groups: albigena, cassiquiarensis, five polyphyletic macrodon groups, three polyphyletic ustus groups, sciureus, collinsi, boliviensis, peruviensis, vanzolinii, oerstedii and citrinellus. Four different phylogenetic trees showed the Central American squirrel monkey (S. oerstedii) as the most differentiated taxon. In contrast, albigena was indicated to be the most recent taxon. (2) There was extensive hybridization and/or historical introgression among albigena, different macrodon groups, peruviensis, sciureus and collinsi. (3) Different tests showed that our maximum likelihood tree was consistent with two species of Saimiri: S. oerstedii and S. sciureus. If no cases of hybridization were detected implicating S. vanzolinii, this could be a third recognized species. (4) We also estimated that the first temporal splits within this genus occurred around 1.4-1.6 million years ago, which indicates that the temporal split events within Saimiri were correlated with Pleistocene climatic changes. If the biological species concept is applied because, in this case, it is operative due to observed hybridization in the wild, the number of species within this genus is probably more limited than recently proposed by other authors. The Pleistocene was the fundamental epoch when the mitochondrial Saimiri diversification process occurred.

  10. Crystal structure and photoluminescence properties of a new Cd(II) coordination polymer catena-poly[bis[4-bromo-2-({[2-(pyrrolidin-1-yl)ethyl]imino}methyl)phenolato-κ(3)N,N',O]di-μ3-chlorido-di-μ2-chlorido-bis(methanol-κO)tricadmium(II)].

    Science.gov (United States)

    Yahsi, Yasemin; Ozbek, Hatice; Aygun, Muhittin; Kara, Hulya

    2016-05-01

    Schiff base-metal complexes have been used widely as catalysts for many organic reactions, such as ring-opening polymerization and oxidation. In view of the importance of Cd(II) coordination polymers and in an effort to enlarge the library of such complexes, the title novel polymeric Cd(II) tridentate Schiff base complex, [Cd3(C13H16BrN2O)2Cl4(CH4O)2]n, has been synthesized and characterized by elemental analyses, UV and IR spectroscopies, and single-crystal X-ray diffraction. The complex crystallizes in the triclinic P-1 space group with two symmetry-independent Cd(II) atoms, one of which lies on an inversion centre, and analysis of the crystal structure shows that both Cd(II) atoms are six-coordinated; the environment around one Cd(II) atom can be described as distorted octahedral, while that around the second Cd(II) atom is octahedral. The Cd(II) atoms are linked by chloride ligands to form a one-dimensional coordination polymer. The nonbonding intermolecular Cd...Cd distances are 3.7009 (4) and 4.3563 (5) Å. Furthermore, the photoluminescence properties of the complex have been investigated and it displays a strong red emission in the solid state at room temperature.

  11. Characterization and Properties of Activated Carbon Prepared from Tamarind Seeds by KOH Activation for Fe(III Adsorption from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Sumrit Mopoung

    2015-01-01

    Full Text Available This research studies the characterization of activated carbon from tamarind seed with KOH activation. The effects of 0.5 : 1–1.5 : 1 KOH : tamarind seed charcoal ratios and 500–700°C activation temperatures were studied. FTIR, SEM-EDS, XRD, and BET were used to characterize tamarind seed and the activated carbon prepared from them. Proximate analysis, percent yield, iodine number, methylene blue number, and preliminary test of Fe(III adsorption were also studied. Fe(III adsorption was carried out by 30 mL column with 5–20 ppm Fe(III initial concentrations. The percent yield of activated carbon prepared from tamarind seed with KOH activation decreased with increasing activation temperature and impregnation ratios, which were in the range from 54.09 to 82.03 wt%. The surface functional groups of activated carbon are O–H, C=O, C–O, –CO3, C–H, and Si–H. The XRD result showed high crystallinity coming from a potassium compound in the activated carbon. The main elements found in the activated carbon by EDS are C, O, Si, and K. The results of iodine and methylene blue adsorption indicate that the pore size of the activated carbon is mostly in the range of mesopore and macropore. The average BET pore size and BET surface area of activated carbon are 67.9764 Å and 2.7167 m2/g, respectively. Finally, the tamarind seed based activated carbon produced with 500°C activation temperature and 1.0 : 1 KOH : tamarind seed charcoal ratio was used for Fe(III adsorption test. It was shown that Fe(III was adsorbed in alkaline conditions and adsorption increased with increasing Fe(III initial concentration from 5 to 20 ppm with capacity adsorption of 0.0069–0.019 mg/g.

  12. Fe(II) sorption on pyrophyllite: Effect of structural Fe(III) (impurity) in pyrophyllite on nature of layered double hydroxide (LDH) secondary mineral formation

    Energy Technology Data Exchange (ETDEWEB)

    Starcher, Autumn N.; Li, Wei; Kukkadapu, Ravi K.; Elzinga, Evert J.; Sparks, Donald L.

    2016-11-01

    Fe(II)-Al(III)-LDH (layered double hydroxide) phases have been shown to form from reactions of aqueous Fe(II) with Fe-free Al-bearing minerals (phyllosilicate/clays and Al-oxides). To our knowledge, the effect of small amounts of structural Fe(III) impurities in “neutral” clays on such reactions, however, were not studied. In this study to understand the role of structural Fe(III) impurity in clays, laboratory batch studies with pyrophyllite (10 g/L), an Al-bearing phyllosilicate, containing small amounts of structural Fe(III) impurities and 0.8 mM and 3 mM Fe(II) (both natural and enriched in 57Fe) were carried out at pH 7.5 under anaerobic conditions (4% H2 – 96% N2 atmosphere). Samples were taken up to 4 weeks for analysis by Fe-X-ray absorption spectroscopy and 57Fe Mössbauer spectroscopy. In addition to the precipitation of Fe(II)-Al(III)-LDH phases as observed in earlier studies with pure minerals (no Fe(III) impurities in the minerals), the analyses indicated formation of small amounts of Fe(III) containing solid(s), most probably hybrid a Fe(II)-Al(III)/Fe(III)-LDH phase. The mechanism of Fe(II) oxidation was not apparent but most likely was due to interfacial electron transfer from the sorbed Fe(II) to the structural Fe(III) and/or surface-sorption-induced electron-transfer from the sorbed Fe(II) to the clay lattice. Increase in the Fe(II)/Al ratio of the LDH with reaction time further indicated the complex nature of the samples. This research provides evidence for the formation of both Fe(II)-Al(III)-LDH and Fe(II)-Fe(III)/Al(III)-LDH-like phases during reactions of Fe(II) in systems that mimic the natural environments. Better understanding Fe phase formation in complex laboratory studies will improve models of natural redox systems.

  13. Solid phase extraction of zinc(II) using a PVC-based polymer inclusion membrane with di(2-ethylhexyl)phosphoric acid (D2EHPA) as the carrier.

    Science.gov (United States)

    Kolev, Spas D; Baba, Yoshinari; Cattrall, Robert W; Tasaki, Tsutomu; Pereira, Natalie; Perera, Jilska M; Stevens, Geoffrey W

    2009-05-15

    A polymer inclusion membrane (PIM) is reported consisting of 45% (m/m) di(2-ethylhexyl)phosphoric acid (D2EHPA) immobilized in poly(vinyl chloride) (PVC) for use as a solid phase absorbent for selectively extracting Zn(II) from aqueous solutions in the presence of Cd(II), Co(II), Cu(II), Ni(II) and Fe(II). Interference from Fe(III) in the sample is eliminated by precipitation with orthophosphate prior to the extraction of Zn(II). Studies using a dual compartment transport cell have shown that the Zn(II) flux (2.58 x 10(-6)mol m(-2)s(-1)) is comparable to that observed for supported liquid membranes. The stoichiometry of the extracted complex is shown to be ZnR(2).HR, where R is the D2EHPA anion.

  14. Synthesis, spectral studies and biological evaluation of 2-aminonicotinic acid metal complexes

    Science.gov (United States)

    Nawaz, Muhammad; Abbasi, Muhammad Waseem; Hisaindee, Soleiman; Zaki, Muhammad Javed; Abbas, Hira Fatima; Mengting, Hu; Ahmed, M. Arif

    2016-05-01

    We synthesized 2-aminonicotinic acid (2-ANA) complexes with metals such as Co(II), Fe(III), Ni(II), Mn(II), Zn(II), Ag(I),Cr(III), Cd(II) and Cu(II) in aqueous media. The complexes were characterized and elucidated using FT-IR, UV-Vis, a fluorescence spectrophotometer and thermo gravimetric analysis (TGA). TGA data showed that the stoichiometry of complexes was 1:2 metal/ligand except for Ag(I) and Mn(II) where the ratio was 1:1. The metal complexes showed varied antibacterial, fungicidal and nematicidal activities. The silver and zinc complexes showed highest activity against Bacillus subtilis and Bacillus licheniformis respectively. Fusarium oxysporum was highly susceptible to nickel and copper complexes whereas Macrophomina phaseolina was completely inert to the complexes. The silver and cadmium complexes were effective against the root-knot nematode Meloidogyne javanica.

  15. Synthesis, spectroscopic characterisation, biological and DNA cleavage properties of complexes of nicotinamide

    Directory of Open Access Journals (Sweden)

    C. Surendra Dilip

    2016-09-01

    Full Text Available Transition metal complexes of nicotinamide with metal precursors such as Cr(III, Mn(II, Fe(III, Co(II, Ni(II, Cu(II and Cd(II, were synthesized and characterised by physico-chemical and spectroscopic techniques. Based on analytical, spectral and magnetic moments, all the complexes are identified as distorted octahedral in structure. All the complexes are of the ML14L22 type. The shifts of the ν (CN (azomethine and ν (CO (amide stretches have been monitored in order to find out the donor sites of the ligands. Antibacterial and antifungal activities of the complexes were studied and the complexes were screened against bacteria and fungi. The activity data show that the metal complexes are more potent than the parent nicotinamide.

  16. Transition Metal Complexes of 1, 4(2'-Hydroxyphenyl-1-yl di-imino azine: Synthesis, Characterization and Antimicrobial Studies

    Directory of Open Access Journals (Sweden)

    M. Revanasiddappa

    2008-01-01

    Full Text Available The synthesis and characterization of first row transition metal complexes of the 1, 4(2'-hydroxyphenyl-1-yl di-imino azine {1,4(2'HPDA} are reported. The complexes have been characterized by elemental analysis, molar conductance, magnetic studies, IR, 1H NMR and UV-visible studies. They have the stoichiometry of the type [M{1,4(2'HPDA}2 2H2O ] and [M'L2] where M= Mn(II, Fe(III, Co(II, Ni(II and Cu(II, and M' = ZrO(II, VO(II, Zn(II, Cd(II, and Hg(II. The antibacterial and antifungal activity of the metal complexes has been investigated. Both ligand and complexes have shown good antibacterial and antifungal activity.

  17. Chelating fibers prepared with a wet spinning technique using a mixture of a viscose solution and a polymer ligand for the separation of metal ions in an aqueous solution.

    Science.gov (United States)

    Kagaya, Shigehiro; Miyazaki, Hiroyuki; Inoue, Yoshinori; Kato, Toshifumi; Yanai, Hideyuki; Kamichatani, Waka; Kajiwara, Takehiro; Saito, Mitsuru; Tohda, Koji

    2012-02-15

    Chelating fibers containing polymer ligands such as carboxymethylated polyallylamine, carboxymethylated polyethyleneimine, and a copolymer of diallylamine hydrochloride/maleic acid were prepared with a wet spinning technique using mixtures of a viscose solution and the polymer ligands. The chelating fibers obtained effectively adsorbed various metal ions, including Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Mn(II), Ni(II), Pb(II), Ti(IV), and Zn(II). The metal ions adsorbed could be readily desorbed using 0.1 or 0.5 mol L(-1) HNO(3). The chelating fiber containing carboxymethylated polyallylamine was available for the separation of some metal ions in synthetic wastewater containing a large amount of Na(2)SO(4). The wet spinning technique using a solution containing a base polymer and a polymer ligand was quite simple and effective and would be applicable for preparing various chelating fibers.

  18. Click on silica: systematic immobilization of Co(II) Schiff bases to the mesoporous silica via click reaction and their catalytic activity for aerobic oxidation of alcohols.

    Science.gov (United States)

    Rana, Bharat S; Jain, Suman L; Singh, Bhawan; Bhaumik, Asim; Sain, Bir; Sinha, Anil K

    2010-09-07

    The systematic immobilization of cobalt(II) Schiff base complexes on SBA-15 mesoporous silica via copper catalyzed [3 + 2] azide-alkyne cycloaddition (CuAAC) "click reaction" involving either step-wise synthesis of silica-bound Schiff base ligand followed by its subsequent complexation with cobalt ions, or by the direct immobilization of preformed Co(II) Schiff base complex to the silica support is described. The catalytic activity of the prepared complexes was studied for the oxidation of alcohols to carbonyl compounds using molecular oxygen as oxidant. The immobilized complexes were recycled for several runs without loss in catalytic activity and no leaching was observed during this course.

  19. Novel FeII and CoII Complexes of Natural Product Tryptanthrin: Synthesis and Binding with G-Quadruplex DNA

    Science.gov (United States)

    Zhong, Yi-ning; Zhang, Yan; Gu, Yun-qiong; Wu, Shi-yun; Shen, Wen-ying

    2016-01-01

    Tryptanthrin is one of the most important members of indoloquinoline alkaloids. We obtained this alkaloid from Isatis. Two novel FeII and CoII complexes of tryptanthrin were first synthesized. Single-crystal X-ray diffraction analyses show that these complexes display distorted four-coordinated tetrahedron geometry via two heterocyclic nitrogen and oxygen atoms from tryptanthrin ligand. Binding with G-quadruplex DNA properties revealed that both complexes were found to exhibit significant interaction with G-quadruplex DNA. This study may potentially serve as the basis of future rational design of metal-based drugs from natural products that target the G-quadruplex DNA. PMID:27698647

  20. Liquid-liquid extraction of Cd(II) from pure and Ni/Cd acidic chloride media using Cyanex 921: a selective treatment of hazardous leachate of spent Ni-Cd batteries.

    Science.gov (United States)

    Choi, Seon-Young; Nguyen, Viet Tu; Lee, Jae-Chun; Kang, Ho; Pandey, B D

    2014-08-15

    The present paper is focused on solvent extraction of hazardous Cd(II) from acidic chloride media by Cyanex 921, a new extractant mixed with 10% (v/v) TBP in xylene. The optimum conditions for extraction and stripping of Cd(II) were investigated with an aqueous feed of 0.1 mol/L Cd(II) in 2.0 mol/L HCl. McCabe-Thiele diagram was in good agreement with the simulation studies, showing the quantitative extraction (99.9%) of Cd(II) within two counter-current stages utilizing 0.30 mol/L Cyanex 921 at O/A ratio of 3/2 in 10 min. Stoichiometry of the complexes extracted was determined and confirmed by numerical treatment and graphical method, revealing the formation of HCdCl3 · 2L and HCdCl3 · 4L for Cyanex 921(L) concentration in the range 0.03-0.1 mol/L and 0.1-1.0 mol/L, respectively. The thermodynamic parameters for the extraction of cadmium were also determined. The stripping efficiency of cadmium from the loaded organic with 0.10 mol/L HCl was 99.6% in a three-stage counter-current process at an O/A ratio of 2/3. Cyanex 921 was successfully applied for the separation of Cd(II) from Ni(II) in the simulated leach liquor of spent Ni-Cd batteries. The study demonstrates the applicability of the present hydrometallurgical approach for the treatment of hazardous waste, the spent Ni-Cd batteries.

  1. 2-{[1-(3,4-Dihydroxyphenyl)methylidene]amino}benzoic acid immobilized Amberlite XAD-16 as metal extractant.

    Science.gov (United States)

    Venkatesh, Gopalan; Singh, Ajai K

    2005-07-15

    2-{[1-(3,4-Dihydroxyphenyl)methylidene]amino}benzoic acid (DMABA) was loaded on Amberlite XAD-16 (AXAD-16) via azo linker and the resulting resin AXAD-16-DMABA explored for enrichment of Zn(II), Mn(II), Ni(II), Pb(II), Cd(II), Cu(II), Fe(III) and Co(II). The optimum pH values for extraction are 6.5-7.0, 5.0-6.0, 5.5-7.5, 5.0-6.5, 6.5-8.0, 5.5-7.0, 4.0-5.0 and 6.0-7.0, respectively. The sorption capacity was found between 97 and 515mumolg(-1) and the preconcentration factors from 100 to 450. Tolerance limits for foreign species are reported. The kinetics of sorption is fast as t(1/2) is Cd(II), Cu(II), Fe(III) and Co(II), respectively. The enrichment on AXAD-16-DMABA coupled with monitoring by flame atomic absorption spectrometry (FAAS) is used to determine all the metal ion ions in river and synthetic water samples, Co in vitamin tablets and Zn in milk samples.

  2. 2-line ferrihydrite: synthesis, characterization and its adsorption behaviour for removal of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions.

    Science.gov (United States)

    Rout, K; Mohapatra, M; Anand, S

    2012-03-21

    Nano-structured 2-line ferrihydrite was synthesized by a pH-controlled precipitation technique at 90 °C. Chemical, X-ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman analyses confirmed the sample to be 2-line ferrihydrite. The nano nature of the prepared sample was studied by transmission electron microscopy (TEM). The surface area obtained by the Brunauer-Emmett-Teller (BET) method was 175.8 m(2) g(-1). The nanopowder so obtained was used to study its behaviour for the removal of Pb(II), Cd(II), Cu(II) and Zn(II) from aqueous solutions. The relative importance of experimental parameters such as solution pH, contact time and concentration of adsorbate on the uptake of various cations was evaluated. By increasing the pH from 2.0 to 5.5, adsorption of the four cations increased. The kinetics parameters were compared by fitting the contact time data to both linear as well as non-linear forms of pseudo-second-order models. Linear forms of both Langmuir and Freundlich models fitted the equilibrium data of all the cations except for Pb(II) which was also fitted to the non-linear forms of both the models as it gave a low R(2) value of 0.85 for the Langmuir model. High Langmuir monolayer capacities of 366, 250, 62.5 and 500 mg g(-1) were obtained for Pb(II), Cd(II), Cu(II) and Zn(II), respectively. Presence of chloride or sulfate had an adverse effect on cation adsorption. The interactive effects on adsorption from solutions containing two, three or four cations were studied. Surprisingly no Cd(II) adsorption was observed in Pb(II)-Cd(II), Pb(II)-Cd(II)-Zn(II) and Pb(II)-Cd(II)-Cu(II)-Zn(II) systems under the studied concentration range. The overall loading capacity of the adsorbent decreased in mixed cation systems. Metal ion loaded adsorbents were characterized by XRD, FTIR and Raman techniques. The high adsorption capability of the 2-lines ferrihydrite makes it a potentially attractive adsorbent for the removal of cations from aqueous solutions.

  3. IR, UV-Vis, magnetic and thermal characterization of chelates of some catecholamines and 4-aminoantipyrine with Fe(III) and Cu(II)

    Science.gov (United States)

    Mohamed, Gehad G.; Zayed, M. A.; El-Dien, F. A. Nour; El-Nahas, Reham G.

    2004-07-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. α-Methyldopa (α-MD) in tablets is used in medication of hypertension. The Fe(III) and Cu(II) chelates with coupled products of adrenaline hydrogen tartarate (AHT), levodopa (LD), α-MD and carbidopa (CD) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical methods like IR, magnetic and UV-Vis spectra are used to investigate the structure of these chelates. Fe(III) form 1:2 (M:catecholamines) chelates while Cu(II) form 1:1 chelates. Catecholamines behave as a bidentate mono- or dibasic ligands in binding to the metal ions. IR spectra show that the catecholamines are coordinated to the metal ions in a bidentate manner with O,O donor sites of the phenolic - OH. Magnetic moment measurements reveal the presence of Fe(III) chelates in octahedral geometry while the Cu(II) chelates are square planar. The thermal decomposition of Fe(III) and Cu(II) complexes is studied using thermogravimetric (TGA) and differential thermal analysis (DTA) techniques. The water molecules are removed in the first step followed immediately by decomposition of the ligand molecules. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  4. Anaerobic humus and Fe(III) reduction and electron transport pathway by a novel humus-reducing bacterium, Thauera humireducens SgZ-1.

    Science.gov (United States)

    Ma, Chen; Yu, Zhen; Lu, Qin; Zhuang, Li; Zhou, Shun-Gui

    2015-04-01

    In this study, an anaerobic batch experiment was conducted to investigate the humus- and Fe(III)-reducing ability of a novel humus-reducing bacterium, Thauera humireducens SgZ-1. Inhibition tests were also performed to explore the electron transport pathways with various electron acceptors. The results indicate that in anaerobic conditions, strain SgZ-1 possesses the ability to reduce a humus analog, humic acids, soluble Fe(III), and Fe(III) oxides. Acetate, propionate, lactate, and pyruvate were suitable electron donors for humus and Fe(III) reduction by strain SgZ-1, while fermentable sugars (glucose and sucrose) were not. UV-visible spectra obtained from intact cells of strain SgZ-1 showed absorption peaks at 420, 522, and 553 nm, characteristic of c-type cytochromes (cyt c). Dithionite-reduced cyt c was reoxidized by Fe-EDTA and HFO (hydrous ferric oxide), which suggests that cyt c within intact cells of strain SgZ-1 has the ability to donate electrons to extracellular Fe(III) species. Inhibition tests revealed that dehydrogenases, quinones, and cytochromes b/c (cyt b/c) were involved in reduction of AQS (9, 10-anthraquinone-2-sulfonic acid, humus analog) and oxygen. In contrast, only NADH dehydrogenase was linked to electron transport to HFO, while dehydrogenases and cyt b/c were found to participate in the reduction of Fe-EDTA. Thus, various different electron transport pathways are employed by strain SgZ-1 for different electron acceptors. The results from this study help in understanding the electron transport processes and environmental responses of the genus Thauera.

  5. A family of enantiopure Fe(III)4 single molecule magnets: fine tuning of energy barrier by remote substituent.

    Science.gov (United States)

    Zhu, Yuan-Yuan; Cui, Chang; Qian, Kang; Yin, Ji; Wang, Bing-Wu; Wang, Zhe-Ming; Gao, Song

    2014-08-21

    A new family of enantiopure star-shaped Fe(III)4 single-molecule magnets (SMMs) with the general formula [Fe4(L(K))6] (H2L = (R or S)-2-((2-hydroxy-1-phenylethylimino methyl)phenol); K = H (), Cl (), Br (), I (), and t-Bu ()), were structurally and magnetically characterized. Complex was reported in our previous paper (Chem. Commun., 2011, 47, 8049-8051). Detailed magnetic measurements and a systematic magneto-structural correlation study revealed that the SMM properties of this series of compounds can be finely tuned by the remote substituent of the ligands. Although the change in the coordination environment of the central Fe(3+) ions is very small, the properties of SMM behavior are changed considerably. All five complexes display frequency dependence of the ac susceptibility. However, the χ peaks of complexes and cannot be observed down to 0.5 K. The fitted anisotropy energy barriers (Ueff) of complexes , , and were 5.9, 7.1, and 11.0 K, respectively. Moreover, the hysteresis loops of these three complexes can be also observed around 0.5 K. Magneto-structural correlation analyses revealed that the coordination symmetry of the central Fe(3+) ion and the intermolecular interaction are two key factors affecting the SMM properties. Deviation to a trigonal prism coordination environment and the existence of intermolecular interactions between neighboring clusters may both reduce the anisotropy energy barriers.

  6. Mixed ligand complex formation of FeIII with boric acid and typical N-donor multidentate ligands

    Indian Academy of Sciences (India)

    G N Mukherjee; Ansuman Das

    2002-06-01

    Equilibrium study of the mixed ligand complex formation of FeIII with boric acid in the absence and in the presence of 2,2'-bipyridine, 1,10-phenanthroline, diethylenetriamine and triethylenetetramine (L) in different molar ratios provides evidence of formation of Fe(OH)2+, Fe(OH)$^{+}_{2}$, Fe(L)3+, Fe(H2BO4), Fe(OH)(H2BO4)-, Fe(OH)2(H2BO4)2-, Fe(L)(H2BO4) and Fe2(L)2(BO4)+ complexes. Fe(L)$^{3+}_{2}$, Fe(L)2(H2BO4) and Fe2(L)4(BO4)+ complexes are also indicated with 2,2'-bipyridine and 1,10-phenanthroline. Complex formation equilibria and stability constants of the complexes at 25 ± 0 × 1° C in aqueous solution at a fixed ionic strength, = 0.1 mol -3 (NaNO3) have been determined by potentiometric method.

  7. Crystal structure of the coordination polymer [FeIII2{PtII(CN4}3

    Directory of Open Access Journals (Sweden)

    Maksym Seredyuk

    2015-01-01

    Full Text Available The title complex, poly[dodeca-μ-cyanido-diiron(IIItriplatinum(II], [FeIII2{PtII(CN4}3], has a three-dimensional polymeric structure. It is built-up from square-planar [PtII(CN4]2− anions (point group symmetry 2/m bridging cationic [FeIIIPtII(CN4]+∞ layers extending in the bc plane. The FeII atoms of the layers are located on inversion centres and exhibit an octahedral coordination sphere defined by six N atoms of cyanide ligands, while the PtII atoms are located on twofold rotation axes and are surrounded by four C atoms of the cyanide ligands in a square-planar coordination. The geometrical preferences of the two cations for octahedral and square-planar coordination, respectively, lead to a corrugated organisation of the layers. The distance between neighbouring [FeIIIPtII(CN4]+∞ layers corresponds to the length a/2 = 8.0070 (3 Å, and the separation between two neighbouring PtII atoms of the bridging [PtII(CN4]2− groups corresponds to the length of the c axis [7.5720 (2 Å]. The structure is porous with accessible voids of 390 Å3 per unit cell.

  8. Paenibacillus guangzhouensis sp. nov., an Fe(III)- and humus-reducing bacterium from a forest soil.

    Science.gov (United States)

    Li, Jibing; Lu, Qin; Liu, Ting; Zhou, Shungui; Yang, Guiqin; Zhao, Yong

    2014-11-01

    A Gram-reaction-variable, rod-shaped, motile, facultatively aerobic and endospore-forming bacterium, designated strain GSS02(T), was isolated from a forest soil. Strain GSS02(T) was capable of reducing humic substances and Fe(III) oxides. Strain GSS02(T) grew optimally at 35 °C, at pH 78 and in the presence of 1% NaCl. The predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C(15:0) and iso-C(16:0) and the polar lipid profile contained mainly phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol, with moderate amounts of two unknown aminophospholipids and a minor amount of one unknown lipid. The DNA G+C content was 53.4 mol%. Comparative 16S rRNA gene sequence analysis showed that strain GSS02(T) was related most closely to Paenibacillus terrigena JCM 21741(T) (98.1% similarity). Mean DNA-DNA relatedness between strain GSS02(T) and P. terrigena JCM 21741(T) was 58.8 ± 0.5%. The phylogenetic, chemotaxonomic and phenotypic results clearly demonstrated that strain GSS02(T) belongs to the genus Paenibacillus and represents a novel species, for which the name Paenibacillus guangzhouensis sp. nov. is proposed. The type strain is GSS02(T) ( =KCTC 33171(T) =CCTCC AB 2013236(T)).

  9. Synthesis, magnetic properties, and STM spectroscopy of cobalt(II) Cubanes [Co(II) (4)(Cl)(4)(HL)(4)].

    Science.gov (United States)

    Scheurer, Andreas; Ako, Ayuk M; Saalfrank, Rolf W; Heinemann, Frank W; Hampel, Frank; Petukhov, Konstantin; Gieb, Klaus; Stocker, Michael; Müller, Paul

    2010-04-26

    Reaction of cobalt(II) chloride hexahydrate with N-substituted diethanolamines H(2)L(2-4) (3) in the presence of LiH in anhydrous THF leads under anaerobic conditions to the formation of three isostructural tetranuclear cobalt(II) complexes [Co(II) (4)(Cl)(4)(HL(2-4))(4)] (4) with a [Co(4)(mu(3)-O)(4)](4+) cubane core. According to X-ray structural analyses, the complexes 4 a,c crystallize in the tetragonal space group I4(1)/a, whereas for complex 4 b the tetragonal space group P$\\bar 4$ was found. In the solid state the orientation of the cubane cores and the formation of a 3D framework were controlled by the ligand substituents of the cobalt(II) cubanes 4. This also allowed detailed magnetic investigations on single crystals. The analysis of the SQUID magnetic susceptibility data for 4 a gave intramolecular ferromagnetic couplings of the cobalt(II) ions (J(1) approximately 20.4 K, J(2) approximately 7.6 K), resulting in an S=6 ground-state multiplet. The anisotropy was found to be of the easy-axis type (D=-1.55 K) with a resulting anisotropy barrier of Delta approximately 55.8 K. Two-dimensional electron-gas (2DEG) Hall magnetization measurements revealed that complex 4 a is a single-molecule magnet and shows hysteretic magnetization characteristics with typical temperature and sweep-rate dependencies below a blocking temperature of about 4.4 K. The hysteresis loops collapse at zero field owing to fast quantum tunneling of the magnetization (QTM). The structural and electronic properties of cobalt(II) cubane 4 a, deposited on a highly oriented pyrolytic graphite (HOPG) surface, were investigated by means of STM and current imaging tunneling spectroscopy (CITS) at RT and standard atmospheric pressure. In CITS measurements the rather large contrast found at the expected locations of the metal centers of the molecules indicated the presence of a strongly localized LUMO.

  10. Speciation of Fe(II) and Fe(III) by the modified ferrozine method, FIA-spectrophotometry, and flame AAS after cloud-point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Giokas, Dimosthenis L.; Paleologos, Evangelos K.; Karayannis, Miltiades I. [Laboratory of Analytical Chemistry, Department of Chemistry, University of Ioannina (Greece)

    2002-07-01

    A method has been developed for the simultaneous determination of traces of Fe(III) and Fe(II) in water by on-line coupling of spectrophotometry with flame atomic absorption spectrometry (FAAS). The method involves cloud-point extraction (CPE) of both species with ammonium pyrrolidinecarbodithioate (APDC) under standard conditions, which facilitates the in situ complexation and extraction of both species. Differentiation of the oxidation states of iron is achieved by using mathematical equations to overcome the interference of Fe(III) in the spectrophotometric determination of Fe(II) when they are both present in the same solution. In this manner the time-consuming and labor-intensive steps of preoxidation of Fe(II) or reduction of Fe(III) are eliminated. By preconcentrating a 10-mL sample solution detection limits as low as 7 {mu}g L{sup -1}, were obtained after a single-step extraction procedure. The relative standard deviation (n=4, 30 {mu}g L{sup -1}) was 2.6 % and 1.8 % for spectrophotometry and FAAS, respectively. Recoveries in the range of 96-105 % were obtained by analysis of spiked real samples. The method was further verified by analyzing a certified reference material (IMEP-9); for this the recovery was 98.5 %. (orig.)

  11. The Role of Coulomb Interactions for Spin Crossover Behaviors and Crystal Structural Transformation in Novel Anionic Fe(III Complexes from a π-Extended ONO Ligand

    Directory of Open Access Journals (Sweden)

    Suguru Murata

    2016-05-01

    Full Text Available To investigate the π-extension effect on an unusual negative-charged spin crossover (SCO FeIII complex with a weak N2O4 first coordination sphere, we designed and synthesized a series of anionic FeIII complexes from a π-extended naphthalene derivative ligand. Acetonitrile-solvate tetramethylammonium (TMA salt 1 exhibited an SCO conversion, while acetone-solvate TMA salt 2 was in a high-spin state. The crystal structural analysis for 2 revealed that two-leg ladder-like cation-anion arrays derived from π-stacking interactions between π-ligands of the FeIII complex anion and Coulomb interactions were found and the solvated acetone molecules were in one-dimensional channels between the cation-anion arrays. A desolvation-induced single-crystal-to-single-crystal transformation to desolvate compound 2’ may be driven by Coulomb energy gain. Furthermore, the structural comparison between quasi-polymorphic compounds 1 and 2 revealed that the synergy between Coulomb and π-stacking interactions induces a significant distortion of coordination structure of 2.

  12. Antimicrobial Activity of Co(II, Ni(II and Cu(II Coordination Compounds with Nitrogen, Oxygen Containing Schiff Base

    Directory of Open Access Journals (Sweden)

    B. K. RAI

    2013-06-01

    Full Text Available A series of complexes of the type [M(EHPQH2X2] where M = Co(II, Ni(II and Cu(II, EHPQH=2-ethyl, [3(hydroxypropyl]-3, 1 4H quinazoline -4-hydrazone, X= Cl-, Br-, I- and No-3 -. The geometry of the complexes have been elucidated in the light of molar mass, elemental analysis, IR, electronic Spectra, molar conductance and magnetic susceptibility. The measured molar conductance value indicates that the complexes are nonelectrolytic in nature. The above observation indicates that Schiff bases EHPQH behave as bidentate ligand and coordination proposes through azomethine N and oxygen atom of alcoholic group of ligand. The remaining coordination sites are satisfied by negative ion such as Ci-, Br-, I- and NB-. The geometry of the Co(II and Ni(II were proposed to be octahedral in geometry whereas Cu(II complexes were proposed to be distorted octahedral. The Schiff bases and its complexes have been evaluated for their antibacterial activity. The complexes show enhanced antibacterial activity than ligand.

  13. DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: synthesis and spectral approach.

    Science.gov (United States)

    Patil, Sangamesh A; Prabhakara, Chetan T; Halasangi, Bhimashankar M; Toragalmath, Shivakumar S; Badami, Prema S

    2015-02-25

    The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, (1)H NMR, (13)C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity.

  14. Synthesis, molecular docking and evaluation of antifungal activity of Ni(II), Co(II) and Cu(II) complexes of porphyrin core macromolecular ligand.

    Science.gov (United States)

    Singh, Urvashi; Malla, Ali Mohammad; Bhat, Imtiyaz Ahmad; Ahmad, Ajaz; Bukhari, Mohd Nadeem; Bhat, Sneha; Anayutullah, Syed; Hashmi, Athar Adil

    2016-04-01

    Porphyrin core dendrimeric ligand (L) was synthesized by Rothemund synthetic route in which p-hydroxy benzaldehyde and pyrrole were fused together. The prepared ligand was complexed with Ni(II), Cu(II) and Co(II) ions, separately. Both the ligand and its complexes were characterized by elemental analysis and spectroscopic studies (FT-IR, UV-Vis, (1)HNMR). Square planar geometries were proposed for Cu(II), Ni(II) and Co(II) ions in cobalt, Nickel and copper complexes, respectively on the basis of UV-Vis spectroscopic data. The ligand and its complex were screened on Candida albicans (ATCC 10231), Aspergillus fumigatus (ATCC 1022), Trichophyton mentagrophytes (ATCC 9533) and Pencillium marneffei by determining MICs and inhibition zones. The activity of the ligand and its complexes was found to be in the order: CuL ˃ CoL ≈ NiL ˃ L. Detection of DNA damage at the level of the individual eukaryotic cell was observed by commet assay. Molecular docking technique was used to understand the ligand-DNA interactions. From docking experiment, we conclude that copper complex interacts more strongly than rest two.

  15. N-donor co-ligands driven two new Co(II)- coordination polymers with bi- and trinuclear units: Crystal structures, and magnetic properties

    Science.gov (United States)

    Zhou, Zhi-Hang; Han, Min-Le; Wu, Ya-Pan; Dong, Wen-Wen; Li, Dong-Sheng; Lu, Jack Y.

    2016-10-01

    Two new Co(II) coordination polymers(CPs), namely [Co2(bpe)2(Hbppc)]n (1) and [Co3(μ3-OH)(bppc)(bpm)(H2O)]·3H2O (2) (H5bppc=biphenyl-2,4,6,3‧,5‧-pentacarboxylic acid, bpe=1,2-bis(4-pyridyl)ethene, bpm=bis(4-pyridyl)amine), have been obtained and characterized by elemental analysis, single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), IR spectra and thermogravimetric analysis (TGA). 1 shows a binodal (4,6)-connected fsc net with a (44·610·8)(44·62) topology, while 2 shows a binodal (5,7)-connected 3D network based on trinuclear [Co3(μ3-OH)]5+ units with unusual (3.46.52.6)(32.46.57.65.7) topology. Variable-temperature magnetic susceptibility measurements reveals that complex 1 shows ferromagnetic interactions between the adjacent Co(II) ions, whereas 2 is a antiferromagnetic system.

  16. DNA cleavage, antibacterial, antifungal and anthelmintic studies of Co(II), Ni(II) and Cu(II) complexes of coumarin Schiff bases: Synthesis and spectral approach

    Science.gov (United States)

    Patil, Sangamesh A.; Prabhakara, Chetan T.; Halasangi, Bhimashankar M.; Toragalmath, Shivakumar S.; Badami, Prema S.

    2015-02-01

    The metal complexes of Co(II), Ni(II) and Cu(II) have been synthesized from 6-formyl-7,8-dihydroxy-4-methylcoumarin with o-toluidine/3-aminobenzotrifluoride. The synthesized Schiff bases and their metal complexes were structurally characterized based on IR, 1H NMR, 13C NMR, UV-visible, ESR, magnetic, thermal, fluorescence, mass and ESI-MS studies. The molar conductance values indicate that complexes are non-electrolytic in nature. Elemental analysis reveals ML2·2H2O [M = Co(II), Ni(II) and Cu(II)] stoichiometry, where 'L' stands for a singly deprotonated ligand. The presence of co-ordinated water molecules were confirmed by thermal studies. The spectroscopic studies suggest the octahedral geometry. Redox behavior of the complexes were confirmed by cyclic voltammetry. All the synthesized compounds were screened for their antibacterial (Escherichia coli, Pseudomonas auregenosa, klebsiella, Proteus, Staphylococcus aureus and salmonella) antifungal (Candida, Aspergillus niger and Rhizopus), anthelmintic (Pheretima posthuma) and DNA cleavage (Calf Thymus DNA) activity.

  17. A Hirshfeld surface analysis, crystal structure and physicochemical studies of a new Cd(II) complex with the 2-amino-4-methylpyrimidine ligand

    Science.gov (United States)

    Klai, Kacem; Kaabi, Kamel; Kaminsky, Werner; Jelsch, Christian; Lefebvre, Frédéric; Ben Nasr, Cherif

    2017-01-01

    A new Cd(II) complex with the monodentate ligand 2-amino-4-methylpyrimidine, [Cd(NO3)2(C5N3H7)2(H2O)2], has been prepared and characterized by single crystal X-ray diffraction, elemental analysis, CP-MAS NMR and IR spectroscopy. The basic coordination patterns of the 2-amino-4-methylpyrimidine coordinated metal cations are slightly distorted octahedra in this compound. The crystal structure is characterized by CdN2O4 octahedra interconnected via O-H…O and O-H…N hydrogen bonds to form layers parallel to the (b, c) plane. The crystal structure is stabilized by sets of hydrogen bonds, one of which is trifurcated. Intermolecular interactions were investigated by Hirshfeld surfaces. The 13C and 15N CP-MAS NMR spectra are discussed and the vibrational absorption bands were identified by infrared spectroscopy. Electronic properties such as HOMO and LUMO energies were derived.

  18. Assembly of 4-, 6- and 8-connected Cd(II) pseudo-polymorphic coordination polymers: Synthesis, solvent-dependent structural variation and properties

    Science.gov (United States)

    Li, Zhao-Hao; Xue, Li-Ping; Miao, Shao-Bin; Zhao, Bang-Tun

    2016-08-01

    The reaction of Cd(NO3)2·4H2O, 2,5-thiophenedicarboxylic acid (H2tdc) and 1,2-bis(imidazol-1‧-yl)methane (bimm) by modulating solvent systems yielded three highly connected pseudo-polymorphic coordination polymers based on different dinuclear [Cd2(CO2)2] subunits bridged by carboxylate groups. Single crystal structural analyses reveal structural variation from 4-connected 2D sql layer, 6-connected 2-fold interpenetrated 3D pcu to 8-connected 3D bcu-type network in compounds 1-3. The structural dissimilarity in the structures dependent on the coordination environments of Cd(II) ions and linking modes of mixed ligand influenced by different solvent systems during the synthesis process. Moreover, thermogravimetric and photoluminescence behaviors of 1-3 were also investigated for the first time, and all the complexes emit blue luminescence in the solid state.

  19. The curve of ion exchange ratio(%)-pH of the interaction between suspended particles with Cd(II) in the Yellow River

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The curve of ion exchange ratio(%)-pH of the interactionbetween suspended particles with Cd(II) in the Yellow River wasstudied. The effects of lysine on this curve have been alsoinvestigated. The results showed that (1) Cadmium in Cd(OH)+ formin the suspended particles exchanges with the cations.The exchangeratio of Cd2+ is nearly at its greatest value in the range of pH(8.0-8.5) in natural aquatic system; (2) Ion exchange ratiodecreases as the concentration of Cd2+ raises from 8.9×10-6 mol/L to 2x8.9 x 10-6mol/L; (3) At the lysine concentration of 6.8x10-6 mol/L, it can promote the ion exchange ratio; (4) Adsorption of thesuspended particles to cadmium is weaker in seawater and Jin ShaRiver than in the Yellow River.

  20. Bioinspired synthesis of hierarchically micro/nano-structured CuI tetrahedron and its potential application as adsorbent for Cd(II) with high removal capacity.

    Science.gov (United States)

    Gao, Shuyan; Yang, Jianmao; Li, Zhengdao; Jia, Xiaoxia; Chen, Yanli

    2012-04-15

    An environment friendly bioinspired strategy for synthesizing hierarchically micro/nano-structured CuI tetrahedron has been developed by combining the stabilization and the reduction performances of l-tryptophan together. A possible growth mechanism of such hierarchical tetrahedron is tentatively proposed. Remarkably, such CuI tetrahedron is found to possess high removal capacity for poisonous Cd(II) ions, 136.3mg/g, and ideal reusability. This is ascribed to the hierarchical micro/nano-structure and chemical adsorption mechanism, which shows great advantages over the traditional nano-scaled adsorbents. These interesting results stand out the promising applications of such hierarchically micro/nano-structured materials in environment. It is also a good example for the organic combination of green chemistry and nanotechnologies for the treatment of contaminated water.

  1. Synthesis, characterization and anti-proliferative activity of Cd(II) complexes with NNN type pyrazole-based ligand and pseudohalide ligands as coligand

    Science.gov (United States)

    Hopa, Cigdem; Yildirim, Hatice; Kara, Hulya; Kurtaran, Raif; Alkan, Mahir

    2014-03-01

    Cd(II) complexes of tridentate nitrogen donor ligand, 2,6-bis(3,4,5-trimethylpyrazolyl)pyridine (btmpp), Cd(btmpp)X2 (X:Cl, ONO or N(CN)2) have been synthesized and characterized by elemental and spectral (FT-IR, 1H NMR, 13C NMR, UV-Vis) analyses, differential thermal analysis and single crystal X-ray diffraction studies. The molecular structure of reported complex 1, revealed distorted square-pyramidal geometry around Cadmium. Complexes 1-3 and corresponding ligand were tested for cytotoxic activity against the human carcinoma cell lines HEP3B (hepatocellular carcinoma), PC3 (prostate adenocarcinoma), MCF7 (breast adenocarcinoma) and Saos2 (osteosarcoma). The results show that, complexes are more cytotoxic than the free ligand and complex 2 is the most cytotoxic complex for PC3.

  2. Tuned synthesis of two coordination polymers of Cd(II) using substituted bent 3-pyridyl linker and succinate: structures and their applications in anion exchange and sorption properties.

    Science.gov (United States)

    Maity, Dilip Kumar; Bhattacharya, Biswajit; Halder, Arijit; Ghoshal, Debajyoti

    2015-12-28

    Two new Cd(II) coordination polymers, namely [Cd(3-bpdh)2(ClO4)2]n (1) and {[Cd(3-bpdh)(suc)(H2O)]·3(H2O)}n (2), have been synthesized using a substituted bent N,N'-donor ligand 2,5-bis-(3-pyridyl)-3,4-diaza-2,4-hexadiene (3-bpdh) and aliphatic dicarboxylate disodium succinate (suc) with Cd(II) perchlorate salts at room temperature by a slow diffusion technique for the exploration of our previous reported work. Both the structures were determined by single-crystal X-ray diffraction analysis and also by other physicochemical methods. Structure analysis revealed that complex 1 is a 1D chain structure containing coordinated perchlorate with a metal centre, and complex 2 shows a porous 3D framework with encapsulation of lattice water molecules into the void along the crystallographic a-axis. The PXRD study shows the bulk purity of both the complexes and TGA analysis of 2 exhibits that the structure is thermally stable up to 250 °C. Complex 1 shows a nice anion exchange property with replacement of weakly coordinated perchlorate with the inclusion of new anions; and the anion exchanged solids were characterised by FT-IR, PXRD and photoluminescence properties. The desolvated framework of 2 exhibits sorption of CO2 and water vapor and surface adsorption of N2 corroborating with the nature of the pore environment present in 2. The photoluminescence study has been also done for both complexes in the solid state which exhibits ligand based emissions at room temperature.

  3. Co-modification of F{sup −} and Fe(III) ions as a facile strategy towards effective separation of photogenerated electrons and holes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuefei; Yu, Rui; Wang, Ping; Chen, Feng [School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070 (China); Yu, Huogen, E-mail: yuhuogen@whut.edu.cn [School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Wuhan 430070 (China); State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070 (China)

    2015-10-01

    Graphical abstract: - Highlights: • The Fe(III)/F-TiO{sub 2} photocatalyst was prepared by a facile, wet chemical method. • Fe(III)/F-TiO{sub 2} exhibited higher photocatalytic activity than TiO{sub 2}, Fe(III)/TiO{sub 2} and F-TiO{sub 2}. • The synergistic effect of Fe(III) and F ions contributed to the enhanced activity of TiO{sub 2}. - Abstract: The combination of cocatalysts for simultaneously promoting rapid transfer of photogenerated electrons and holes is one of the effective strategies to improve photocatalytic activity of semiconductor photocatalysts. In this study, highly efficient TiO{sub 2} photocatalyst with co-modification of F and Fe(III) ions was prepared by a facile two wet-chemical method including Fe(III) ions impregnation and then F-ion adsorption on the TiO{sub 2} surface. The photocatalytic results demonstrated that the simultaneously modified Fe(III)/F-TiO{sub 2} photocatalyst exhibited obvious enhancement of photocatalytic performance compared with the pure TiO{sub 2} and single-component modified Fe(III)/TiO{sub 2} and F-TiO{sub 2}. Based on the present experimental results, we propose a possible synergistic effect of Fe(III) and F ions to illustrate the enhanced photocatalytic activity of Fe(III)/F-TiO{sub 2} photocatalyst, namely the Fe(III) ions act as effective active sites to rapidly transfer the photogenerated electrons in the CB of TiO{sub 2} and then reduce oxygen, while F ions work as other effective active sites to rapidly transfer the photogenerated holes in the VB of TiO{sub 2} and then form free hydroxide radical to oxidize the organic substances. As a result, the transfer rate and the interfacial catalytic reaction of photogenerated electrons and holes were simultaneously accelerated, which resulted in the enhanced photocatalytic performance of Fe(III)/F-TiO{sub 2} photocatalyst. Due to the low cost and abundant resource of Fe and F, the obtained photocatalyst is promising for practical application. Furthermore, the

  4. Bacteria attenuation by iron electrocoagulation governed by interactions between bacterial phosphate groups and Fe(III) precipitates.

    Science.gov (United States)

    Delaire, Caroline; van Genuchten, Case M; Amrose, Susan E; Gadgil, Ashok J

    2016-10-15

    Iron electrocoagulation (Fe-EC) is a low-cost process in which Fe(II) generated from an Fe(0) anode reacts with dissolved O2 to form (1) Fe(III) precipitates with an affinity for bacterial cell walls and (2) bactericidal reactive oxidants. Previous work suggests that Fe-EC is a promising treatment option for groundwater containing arsenic and bacterial contamination. However, the mechanisms of bacteria attenuation and the impact of major groundwater ions are not well understood. In this work, using the model indicator Escherichia coli (E. coli), we show that physical removal via enmeshment in EC precipitate flocs is the primary process of bacteria attenuation in the presence of HCO3(-), which significantly inhibits inactivation, possibly due to a reduction in the lifetime of reactive oxidants. We demonstrate that the adhesion of EC precipitates to cell walls, which results in bacteria encapsulation in flocs, is driven primarily by interactions between EC precipitates and phosphate functional groups on bacteria surfaces. In single solute electrolytes, both P (0.4 mM) and Ca/Mg (1-13 mM) inhibited the adhesion of EC precipitates to bacterial cell walls, whereas Si (0.4 mM) and ionic strength (2-200 mM) did not impact E. coli attenuation. Interestingly, P (0.4 mM) did not affect E. coli attenuation in electrolytes containing Ca/Mg, consistent with bivalent cation bridging between bacterial phosphate groups and inorganic P sorbed to EC precipitates. Finally, we found that EC precipitate adhesion is largely independent of cell wall composition, consistent with comparable densities of phosphate functional groups on Gram-positive and Gram-negative cells. Our results are critical to predict the performance of Fe-EC to eliminate bacterial contaminants from waters with diverse chemical compositions.

  5. Plausible mechanisms of the fenton-like reactions, M = Fe(II) and Co(II), in the presence of RCO2(-) substrates: are OH(•) radicals formed in the process?

    Science.gov (United States)

    Kornweitz, Haya; Burg, Ariela; Meyerstein, Dan

    2015-05-01

    DFT calculations concerning the plausible mechanism of Fenton-like reactions catalyzed by Fe(II) and Co(II) cations in the presence of carboxylate ligands suggest that hydroxyl radicals are not formed in these reactions. This conclusion suggests that the commonly accepted mechanisms of Fenton-like reactions induced oxidative stress and advanced oxidation processes have to be reconsidered.

  6. Synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(II) complexes of tridentate Schiff base derived from vanillin and DL-α-aminobutyric acid

    Science.gov (United States)

    Nair, M. Sivasankaran; Joseyphus, R. Selwin

    2008-09-01

    Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from vanillin and DL-α-aminobutyric acid were synthesized and characterized by elemental analysis, IR, electronic spectra, conductance measurements, magnetic measurements, powder XRD and biological activity. The analytical data show the composition of the metal complex to be [ML(H 2O)], where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. IR results demonstrate the tridentate binding of the Schiff base ligand involving azomethine nitrogen, phenolic oxygen and carboxylato oxygen atoms. The IR data also indicate the coordination of a water molecule with the metal ion in the complex. The electronic spectral measurements show that Co(II) and Ni(II) complexes have tetrahedral geometry, while Cu(II) complex has square planar geometry. The powder XRD studies indicate that Co(II) and Cu(II) complexes are amorphous, whereas Ni(II) and Zn(II) complexes are crystalline in nature. Magnetic measurements show that Co(II), Ni(II) and Cu(II) complexes have paramagnetic behaviour. Antibacterial results indicated that the metal complexes are more active than the ligand.

  7. "Two-point" assembling of Zn(II) and Co(II) metalloporphyrins derivatized with a crown ether substituent in Langmuir and Langmuir-Blodgett films.

    Science.gov (United States)

    Noworyta, Krzysztof; Marczak, Renata; Tylenda, Rafal; Sobczak, Janusz W; Chitta, Raghu; Kutner, Wlodzimierz; D'Souza, Francis

    2007-02-27

    The effect of "two-point" interactions of Zn(II) and Co(II) metalloporphyrins, bearing 15-crown-5 ether peripheral substituents, on their assembling in Langmuir and Langmuir-Blodgett (LB) films was investigated. That is, simultaneously, the central metal ion of the porphyrin was axially ligated by a nitrogen-containing ligand in the emerged part of the Langmuir film on one hand, and a suitably selected cation pertaining in the subphase solution was supramolecularly complexed by the crown ether moiety in the submerged part of the film on the other. The compression and polarity properties of the Langmuir films of the derivatized free-base 5,10,15-triphenyl-20-(benzo-15-crown-5)porphyrin, H2(TPMCP), and the corresponding cobalt(II) and zinc(II) metalloporphyrins, denoted as Co(TPMCP) and Zn(TPCMP), respectively, as well as inclusion complexes of the metalloporphyrins with selected cations were investigated. For the axial ligation of Zn(II) and Co(II), pyrazine (pyz) and 4,4'-bipyridnine (bpy) aromatic as well as piperazine (ppz) and 1,4-diazabicyclo[2.2.2]octane (DABCO) cyclic heteroaliphatic ligands were selected. The films were formed on the water subphase solution in the absence and presence of LiCl, NaCl, or NH4Cl. The Langmuir films were built of monolayer J-type aggregates of tilted porphyrin macrocycles. The porphyrins formed rather labile complexes with the cations in the subphase. Nevertheless, the XPS analysis revealed that these cations were LB transferred together with the porphyrins onto solid substrates. In the Co(TPMCP) Langmuir films formed on the water subphases, Co(II) was complexed by aromatic but not cyclic heteroaliphatic ligands, while, in these films formed on the NaCl subphase solutions, the metalloporphyrin was also complexed by DABCO. In Langmuir films spread on alkaline subphase solutions, both aromatic and heteroaliphatic ligands formed complexes with Co(TPMCP) of different stoichiometries. The X-ray reflectivity and GIXD measurements

  8. Synthesis, characterization and in vitro antimicrobial studies of Co(II), Ni(II) and Cu(II) complexes derived from macrocyclic compartmental ligand

    Science.gov (United States)

    El-Gammal, O. A.; Bekheit, M. M.; El-Brashy, S. A.

    2015-02-01

    New Co(II), Ni(II) and Cu(II) complexes derived from tetradentate macrocyclic nitrogen ligand, (1E,4E,8E,12E)-5,8,13,16-tetramethyl-1,4,9,12-tetrazacyclohexadeca-4,8,12,16-tetraene (EDHDH) have been synthesized. The complexes have been characterized by elemental analysis, spectral (IR, UV-Vis, 1H NMR and ESR (for Cu(II) complex)) mass, and magnetic as well as thermal analysis measurements. The complexes afforded the formulae: [Cu(EDHDH)Cl2]·2EtOH and [M(EDHDH)X2]·nH2O where M = Co(II) and Ni(II), X = Cl- or OH-, n = 1,0, respectively. The data revealed an octahedral arrangement with N4 tetradentate donor sites in addition to two Cl atoms occupying the other two sites. ESR spectrum of Cu2+ complex confirmed the suggested geometry with values of a α2and β2 indicating that the in-plane σ-bonding and in-plane π-bonding are appreciably covalent, and are consistent with very strong σ-in-plane bonding in the complexes. The molecular modeling is drawn and showed the bond length, bond angle, chemical reactivity, energy components (kcal/mol) and binding energy (kcal/mol) for all the title compounds using DFT method. Also, the thermal behavior and the kinetic parameters of degradation were determined using Coats-Redfern and Horowitz-Metzger methods. Moreover, the in vitro antibacterial studies of all compounds screened against pathogenic bacteria (two Gram +ve and two Gram -ve) to assess their inhibiting potential. The assay indicated that the inhibition potential is metal ion dependent. The ligand, EDHDH, Co(II) and Cu(II) complexes exhibited a remarkable antibacterial activity against Streptococcus Pyogenes as Gram +ve and Proteus vulgaris as Gram -ve bacterial strains. On the other hand, Ni(II) complex revealed a moderate antibacterial activity against both Gram +ve organisms and no activity against Gram -ve bacterial strain.

  9. Preconcentration of Cu(II), Cd(II) and Pb(II) on Amberlite XAD-4 resin functionalized with N,N'-bis(o-vanillinidene)-ethylenediamine and their determination by FAAS in water samples.

    Science.gov (United States)

    Efendioğlu, Ayşegül; Yağan Aşcı, Mehtap; Batı, Bekir

    2010-01-01

    A new polystyrene divinylbenzene-based chelating resin was synthesized by functionalizing Amberlite XAD-4 with N,N'-bis(o-vanillinidene)ethylenediamine. This resin was capable of preconcentrating Cu(II), Cd(II) and Pb(II) in water samples prior to FAAS determination. Various parameters, such as the pH, eluent type and concentration, volume of the eluent and the sample, and diverse ion effects have been studied. The recoveries for the analytes under the optimum working conditions were higher than 95%. The accuracy of the method was tested with standard reference materials (MBH-C31XB20, GBW-02703 and CRM BCR-32) and Cd(II), Cu(II) and Pb(II) standard solutions. The method was successfully applied to water samples.

  10. New Mn(II, Ni(II, Cd(II, Pb(II complexes with 2-methylbenzimidazole and other ligands. Synthesis, spectroscopic characterization, crystal structure, magnetic susceptibility and biological activity studies

    Directory of Open Access Journals (Sweden)

    Shayma A. Shaker

    2016-11-01

    Full Text Available Synthesis and characterization of Mn(II, Ni(II, Cd(II and Pb(II mixed ligand complexes of 2-methylbenzimidazole with other ligands have been reported. The structure of the ligands and their complexes was investigated using elemental analysis, IR, UV–Vis, (1H, 13C NMR spectroscopy, molar conductivity and magnetic susceptibility measurements. In all the studies of complexes, the 2-methylbenzimidazole behaves as a neutral monodentate ligand which is coordinated with the metal ions through the N atom. While benzotriazole behaves as a neutral bidentate ligand which is coordinated with the Ni(II ion through the two N atoms. Moreover, the N-acetylglycine behaves as a bidentate ligand which is coordinated with the Mn(II, Ni(II and Pb(II ions through the N atom and the terminal carboxyl oxygen atom. The magnetic and spectral data indicate the tetrahedral geometry for Mn(II complex, irregular tetrahedral geometry for Pb(II complex and octahedral geometry for Ni(II complex. The X-ray single crystal diffraction method was used to confirm a centrosymmetric dinuclear Cd(II complex as each two metal ions are linked by a pair of thiocyanate N = S bridge. Two 2-methylbenzimidazole N-atom donors and one terminal thiocyanate N atom complete a highly distorted square pyramid geometry around the Cd atom. Besides, different cell types were used to determine the inhibitory effect of Mn(II, Ni(II, Cd(II and Pb(II complexes on cell growth using MTT assay. Cd(II complex showed cytotoxic effect on various types of cancer cell lines with different EC50 values.

  11. Characterization of Cu(II) and Cd(II) resistance mechanisms in Sphingobium sp. PHE-SPH and Ochrobactrum sp. PHE-OCH and their potential application in the bioremediation of heavy metal-phenanthrene co-contaminated sites.

    Science.gov (United States)

    Chen, Chen; Lei, Wenrui; Lu, Min; Zhang, Jianan; Zhang, Zhou; Luo, Chunling; Chen, Yahua; Hong, Qing; Shen, Zhenguo

    2016-04-01

    Soil that is co-contaminated with heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) is difficult to bioremediate due to the ability of toxic metals to inhibit PAH degradation by bacteria. We demonstrated the resistance mechanisms to Cu(II) and Cd(II) of two newly isolated strains of Sphingobium sp. PHE-SPH and Ochrobactrum sp. PHE-OCH and further tested their potential application in the bioremediation of HM-phenanthrene (PhA) co-contaminated sites. The PHE-SPH and PHE-OCH strains tolerated 4.63 and 4.34 mM Cu(II) and also showed tolerance to 0.48 and 1.52 mM Cd(II), respectively. Diverse resistance patterns were detected between the two strains. In PHE-OCH cells, the maximum accumulation of Cu(II) occurred in the cell wall, while the maximum accumulation was in the cytoplasm of PHE-SPH cells. This resulted in a sudden suppression of growth in PHE-OCH and a gradual inhibition in PHE-SPH as the concentration of Cu(II) increased. Organic acid production was markedly higher in PHE-OCH than in PHE-SPH, which may also have a role in the resistance mechanisms, and contributes to the higher Cd(II) tolerance of PHE-OCH. The factors involved in the absorption of Cu(II) or Cd(II) in PHE-SPH and PHE-OCH were identified as proteins and carbohydrates by Fourier transform infrared (FT-IR) spectroscopy. Furthermore, both strains showed the ability to efficiently degrade PhA and maintained this high degradation efficiency under HM stress. The high tolerance to HMs and the PhA degradation capacity make Sphingobium sp. PHE-SPH and Ochrobactrum sp. PHE-OCH excellent candidate organisms for the bioremediation of HM-PhA co-contaminated sites.

  12. Solid phase extraction of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) ions with 1-(2-thiazolylazo)-2-naphthol loaded Amberlite XAD-1180.

    Science.gov (United States)

    Tokalioğlu, Serife; Yilmaz, Vedat; Kartal, Senol

    2009-05-01

    A new method for separation and preconcentration of trace amounts of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) ions in various matrices was proposed. The method is based on the adsorption and chelation of the metal ions on a column containing Amberlite XAD-1180 resin impregnated with 1-(2-thiazolylazo)-2-naphthol (TAN) reagent prior to their determination by flame atomic absorption spectrometry (FAAS). The effect of pH, type, concentration and volume of eluent, sample volume, flow rates of sample and elution solutions, and interfering ions have been investigated. The optimum pH for simultaneous retention of all the metal ions was 9. Eluent for quantitative elution was 20 ml of 2 mol l(-1) HNO(3). The optimum sample and eluent flow rates were found as 4 ml min(-1), and also sample volume was 500 ml, except for Mn (87% recovery). The sorption capacity of the resin was found to be 0.77, 0.41, 0.57, and 0.30 mg g(-1) for Cu(II), Ni(II), Cd(II), and Mn(II), respectively. The preconcentration factor of the method was 200 for Cu(II), 150 for Pb(II), 100 for Cd(II) and Ni(II), and 50 for Mn(II). The recovery values for all of the metal ions were > or = 95% and relative standard deviations (RSDs) were < or = 5.1%. The detection limit values were in the range of 0.03 and 1.19 microg l(-1). The accuracy of the method was confirmed by analysing the certified reference materials (TMDA 54.4 fortified lake water and GBW 07605 tea samples) and the recovery studies. This procedure was applied to the determination of Cu(II), Ni(II), Pb(II), Cd(II) and Mn(II) in waste water and lake water samples.

  13. Structural, spectroscopic and redox properties of a mononuclear Co(II) thiolate complex--the reactivity toward S-alkylation: an experimental and theoretical study.

    Science.gov (United States)

    Gennari, Marcello; Gerey, Bertrand; Hall, Nikita; Pécaut, Jacques; Vezin, Hervé; Collomb, Marie-Noëlle; Orio, Maylis; Duboc, Carole

    2012-10-28

    The structural, spectroscopic, redox properties and also the reactivity toward S-alkylation of a new mononuclear N2S2 dithiolate Co(II) complex [CoL] (1), with H(2)L = 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(1,1-diphenylethanethiol), have been investigated. The X-ray structure of 1 has revealed an unusual distorted square planar geometry for a Co(II) ion within a thiolate environment. The X-band EPR spectrum of displays a rhombic S = 1/2 signal consistent with a low spin configuration for the d(7) Co(II) ion with a large g-anisotropy (g(x) = 2.94, g(y) = 2.32 and g(z) = 2.01). By pulsed EPR experiments (HYSCORE), two weak hyperfine couplings (hfc) of 3.2 and 2.2 MHz have been measured and attributed respectively to protons and nitrogen nuclei of the bipyridine unit. In addition, another hyperfine coupling (hfc) of 7.5 MHz has been attributed to the cobalt ion. DFT calculations have successfully reproduced the (59)Co and (14)N hfc parameters. However, multiconfigurational ab initio calculations were required to predict the g-tensor of 1. The cyclic voltammogram (CV) displays two one-electron metal based processes: a quasi-reversible Co(III)/Co(II) oxidation wave at E(1/2) = -0.5 V vs. Fc(+)/Fc and a quasi-reversible Co(II)/Co(I) reduction wave at E(1/2) = -1.7 V. 1 reacts with CH(3)I, generating the mono S-methylated complex, [CoL(Me)I] (1(Me)). The X-band EPR spectrum of 1(Me) displays a typical signal of a high spin (S = 3/2) Co(II) species. An optimized structure of 1(Me), calculated by DFT, is consistent with its EPR and UV-visible spectra. Time dependent density functional theory (TD-DFT) calculations attribute the most prominent features observed in the electronic absorption spectra of 1 and 1(Me). The singly occupied MO (SOMO) of 1 shows a notable delocalization of the unpaired electron over the metal (85%) and the ligand, especially over the sulphur atoms (10.5%), indicating a certain degree of covalency for the Co-S bonds. In 1(Me), for two of the three SOMOs

  14. Synthesis, Spectral and Antimicrobial Studies of Some Co(II, Ni(II and Cu(II Complexes Containing 2-Thiophenecarboxaldehyde Moiety

    Directory of Open Access Journals (Sweden)

    A. P. Mishra

    2012-01-01

    Full Text Available Some new Schiff base metal complexes of Co(II, Ni(II and Cu(II derived from 3-chloro-4-fluoroaniline (HL1 and 4-fluoroaniline (HL2 with 2-thiophenecarboxaldehyde have been synthesized and characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR and magnetic susceptibility. The complexes exhibit coordination number 4 or 6. The complexes are colored and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal: ligand ratio. FAB-mass data show degradation pattern of the complexes. The Schiff base and metal complexes show a good activity against the bacteria; B. subtilis, E. coli and S. aureus and fungi A. niger, A. flavus and C. albicans. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases.

  15. Development and molecular modeling of Co(II, Ni(II and Cu(II complexes as high acting anti breast cancer agents

    Directory of Open Access Journals (Sweden)

    S.A. Deodware

    2017-02-01

    Full Text Available A series of cobalt, nickel and copper complexes of bidentate Schiff base derived from the condensation reaction of 4-amino-5-mercapto-3-methyl-1,2,4-triazole with 2-nitrobenzaldehyde had been synthesized. The synthesized Schiff base and their metal complexes have been characterized with the support of more than a few physicochemical techniques, elemental evaluation, magnetic moment measurements, spectroscopic, thermo gravimetric techniques and X-ray powder diffraction. Spectral analysis exhibits square planer geometry for Cu(II complex while octahedral geometry for Co(II and Ni(II complexes. The Schiff base and their complexes have been screened for their anticancer activity using MCF7 cell line. In molecular docking learn exhibits that Ni(II complex is more active confirmed quantity of interaction in particular hydrogen bond interaction with ASN142 and charge interactions with ASP97 and GLU99.

  16. Adsorption of Co(II), Ni(II), Pb(II) and U(VI) from Aqueous Solutions using Polyaniline/Graphene Oxide Composites

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhengjie; Li, Changzhen; Dong, Yunhui; Li, Yueyun [Shandong University of Technology, Zibo (China); Yang, Jianwei [Shandong Moris Technology Co.. Ltd, Weifang (China); Li, Jiaxing [Chinese Academy of Sciences, Hefei (China); Jiang, Yajuan [Sinopec Beijing Yanshan Company, Beijing (China)

    2014-12-15

    Polyaniline modified graphene oxide (PANI/GO) composites were synthesized by dilute polymerization technique and were characterized by Fourier transformed infrared spectroscopy (FTIR), Raman spectroscopy, and scanning electron microscopy (SEM). The characterization results indicated that polyaniline molecules were successfully grafted on GO surfaces. The application of PANI/GO composites to the adsorption of heavy metals from aqueous solutions was investigated under ambient conditions. The maximum adsorption capacities of Co(II), Ni(II), Pb(II) and U(VI) ions on PANI/GO composites calculated from Langmuir models are 22.28, 25.67, 65.40 and 1552.31 mg/g, respectively. The excellent adsorption capacity suggests that PANI/GO composites can be applied as a promising adsorbent in heavy metal pollution cleanup in environmental pollution management.

  17. Self-assembly of a Co(II) dimer through H-bonding of water molecules to a 3D open-framework structure

    Indian Academy of Sciences (India)

    Sujit K Ghosh; Parimal K Bharadwaj

    2005-01-01

    Reaction of pyridine-2,4,6-tricarboxylic acid (ptcH3) with Co(NO3)2.6H2O in presence of 4,4'-bipyridine (4,4'-bpy) in water at room temperature results in the formation of {[Co2(ptcH)2(4,4'-bpy)(H2O)4].2H2O}, (1). The solid-state structure reveals that the compound is a dimeric Co(II) complex assembled to a 3D architecture via an intricate intra- and inter-molecular hydrogen-bonding interactions involving water molecules and carboxylate oxygens of the ligand ptcH2-. Crystal data: monoclinic, space group 21/, = 11.441(5) Å, = 20.212(2) Å, = 7.020(5) Å, = 103.77(5)°, = 1576.7(1) Å3, = 2, 1 = 0.0363, 2 = 0.0856, = 1.000.

  18. Determination of Co(II) in Pharmaceutical Formulations and Evaluation of Formed Species During Complexation by UV-Vis with Br-TDB

    OpenAIRE

    Vitor Hugo Migues; Universidade Estadual do Sudoeste da Bahia; Regina T. Yamaki; Universidade Estadual do Sudoeste da Bahia

    2015-01-01

    The goal of this work was to determine cobalt in pharmaceutical formulations and the formed species during complexation with 6-[2'-(5-bromothiazolylazo)]-1,2-dihydroxy-3,5-benzenedisulfonic reagent (Br-TDB). The log beta values for the formed complex species ML2H24-, ML2H5- and ML26- (M = Co(II) and L = Br-TDB4-) were 29.26 ± 0.03, 25.11 ± 0.04 and 16.7 ± 0.11. The stoichiometry of the complex is 1:2 and the time of reaction equals 10 minutes. The complex absorbs at 620 nm. The limits of quan...

  19. Synthesis, Characterization and Antimicrobial Activities of 1,2,4-Triazole /Isatin Schiff bases and their Mn(II, Co(II complexes

    Directory of Open Access Journals (Sweden)

    Sunita Bajroliya

    2014-12-01

    Full Text Available Mn(II and Co(II metal complexes have been synthesized with newly synthesized Schiff bases derived from isatin/5-nitroisatin and 3-substituted-4-amino-5-mercapto-1,2,4-triazole by new environmental benign microwave irradiation method as well as conventional method. Reaction achieved by microwave irradiation technique, require drastically reduced reaction time and provide high yield with improved selectivity as compared to conventional method. The synthesized compounds were characterized by elemental analysis as well as spectral studies. The elemental analysis were clearly indicated that ML2 type complexes have 1:2 stoichiometry (M=metal, L=ligand. The synthesized Schiff bases and their metal complexes screened for antimicrobial activities against selected bacteria and fungi.

  20. Synthesis, characterization, in vitro antimicrobial and DNA cleavage studies of Co(II), Ni(II) and Cu(II) complexes with ONOO donor coumarin Schiff bases

    Science.gov (United States)

    Patil, Sangamesh A.; Unki, Shrishila N.; Kulkarni, Ajaykumar D.; Naik, Vinod H.; Badami, Prema S.

    2011-01-01

    A series of Co(II), Ni(II) and Cu(II) complexes have been synthesized with Schiff bases derived from 2-hydroxy-1-naphthaldehyde and 2-oxo-2H-chromene-3-carbohydrazide/6-bromo-2-oxo-2H-chromene-3-carbohydrazide. The chelation of the complexes has been proposed in the light of analytical, spectral (IR, UV-Vis, 1H NMR, ESR, FAB-mass and fluorescence), magnetic and thermal studies. The measured molar conductance values indicate that, the complexes are non-electrolytic in nature. The redox behavior of the complexes was investigated with electrochemical method by using cyclic voltammetry. The Schiff bases and their metal complexes have been screened for their in vitro antibacterial ( Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Salmonella typhi) and antifungal activities ( Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The DNA cleavage is studied by agarose gel electrophoresis method.

  1. Influence of pseudohalide anions on the structural assembly of Cd(II) coordination polymers with 3,4-bis(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole

    Science.gov (United States)

    Chen, Jing; Li, Ming-Ze; Sun, Nan; Guo, Jian-Hua

    2016-02-01

    Four CdII coordination polymers, namely {[Cd(L334)(Cl)2](CH3OH)}n (1), [Cd(L334)(Cl)(dca)]n (2), {[Cd(L334)(Cl)1.33(N3)0.67](H2O)}n (3), and {[Cd(L334)(SCN)2(H2O)](H2O)1.5(CH3OH)}n (4), have been synthesized by the conventional reactions of CdCl2 and 3,4-bis(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole (L334) or in the presence of different pseudohalides dicyanamide (dca), azide (N3), and thiocyanate (SCN), respectively as auxiliary ligands. Complexes 1-3 exhibit the isostructural 2D layered network structures, whereas complex 4 shows a distinct 2D network with dimeric CdII subunits. The structural discrepancy in 1-4 indicates the significant influence of pseudohalide anions on the structural assembly of CdII coordination polymers with 3,4-bis(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole. In addition, thermogravimetric and fluorescent properties for all complexes and the ligand have also been investigated.

  2. Influence of different mineral and Organic pesticide treatments on Cd(II), Cu(II), Pb(II), and Zn(II) contents determined by derivative potentiometric stripping analysis in Italian white and red wines.

    Science.gov (United States)

    Salvo, Francesco; La Pera, Lara; Di Bella, Giuseppa; Nicotina, Mariano; Dugo, Giacomo

    2003-02-12

    This paper deals with the use of derivative potentiometric stripping analysis (dPSA) as a rapid and precise method to determine Cd(II), Cu(II), Pb(II), and Zn(II) levels in red and white wine samples from Sicily, Campania, and Tuscany and to investigate the possible connection between the content of these metals and the pesticide treatments used in vine-growing to control plant diseases and pests. dPSA allowed direct quantitation of heavy metals in acidified wines without any sample pretreatment. Mean recoveries of Cd(II), Cu(II), Pb(II), and Zn(II) ranged from 95.5 to 99.2% for white wine samples and from 96.1 to 100.0% for red wine samples. The obtained results showed that Cd(II) was not found in any sample and that Cu(II), Pb(II), and Zn(II) levels were always lower than the toxicity limits in both fungicide- and water-treated wines. Nevertheless, the contents of metals were increased in samples from organic and inorganic pesticides treatment with respect to the water-treated samples. In particular, quinoxyfen, dinocap-penconazole, and dinocap applications considerably increased Cu(II) and Zn(II) contents in white and red wines. The levels of lead were significantly raised by azoxystrobin and sulfur treatments.

  3. Azocalix[4]pyrrole Amberlite XAD-2: new polymeric chelating resins for the extraction, preconcentration and sequential separation of Cu(II), Zn(II) and Cd(II) in natural water samples.

    Science.gov (United States)

    Jain, Vinod K; Mandalia, Hiren C; Gupte, Hrishikesh S; Vyas, Disha J

    2009-10-15

    Two novel azocalix[4]pyrrole Amberlite XAD-2 polymeric chelating resins were synthesized by covalently linking diazotized Amberlite XAD-2 with calix[4]pyrrole macrocycles. The chelating resins were used for extraction, preconcentration and sequential separation of metal ions such as Cu(II), Zn(II) and Cd(II) by column chromatography prior to their determination by UV/vis spectrophotometry or flame atomic absorption spectrophotometry (FAAS) or inductively coupled plasma atomic emission spectroscopy (ICP-AES). Various parameters such as effect of pH on absorption, concentration of eluting agents, flow rate, total sorption capacity, exchange kinetics, preconcentration factor, distribution coefficient, breakthrough capacity and resin stability, were optimized for effective separation and preconcentration. The resin showed good ability for the separation of metal ions from binary and ternary mixture on the basis of pH of absorption and concentration of eluting agents. The newly synthesized resins showed good potential for trace enrichment of Cu(II), Zn(II) and Cd(II) metal ions, especially for Cu(II), as compared to the earlier reported resins. The synthesized resins were recycled at least 8-10 times without much affecting column sorption capacity. The presented method was successfully applied for determination of Cu(II), Zn(II) and Cd(II) in natural and ground water samples.

  4. Direct Involvement of ombB, omaB and omcB Genes in Extracellular Reduction of Fe(III by Geobacter sulfurreducens PCA

    Directory of Open Access Journals (Sweden)

    Yimo eLiu

    2015-10-01

    Full Text Available The tandem gene clusters orfR-ombB-omaB-omcB and orfS-ombC-omaC-omcC of the metal-reducing bacterium Geobacter sulfurreducens PCA are responsible for trans-outer membrane electron transfer during extracellular reduction of Fe(III-citrate and ferrihydrite [a poorly crystalline Fe(III oxide]. Each gene cluster encodes a putative transcriptional factor (OrfR/OrfS, a porin-like outer-membrane protein (OmbB/OmbC, a periplasmic c-type cytochrome (c-Cyt, OmaB/OmaC and an outer-membrane c-Cyt (OmcB/OmcC. The individual roles of OmbB, OmaB and OmcB in extracellular reduction of Fe(III, however, have remained either uninvestigated or controversial. Here, we showed that replacements of ombB, omaB, omcB and ombB-omaB with an antibiotic gene in the presence of ombC-omaC-omcC had no impact on reduction of Fe(III-citrate by G. sulfurreducens PCA. Disruption of ombB, omaB, omcB and ombB-omaB in the absence of ombC-omaC-omcC, however, severely impaired the bacterial ability to reduce Fe(III-citrate as well as ferrihydrite. These results unequivocally demonstrate an overlapping role of ombB-omaB-omcB and ombC-omaC-omcC in extracellular Fe(III reduction by G. sulfurreducens PCA. Involvement of both ombB-omaB-omcB and ombC-omaC-omcC in extracellular Fe(III reduction reflects the importance of these trans-outer membrane protein complexes in the physiology of this bacterium. Moreover, the kinetics of Fe(III-citrate and ferrihydrite reduction by these mutants in the absence of ombC-omaC-omcC were nearly identical, which suggests that absence of any protein subunit eliminates function of OmaB/OmbB/OmcB protein complex. Finally, orfS was found to have a negative impact on the extracellular reduction of Fe(III-citrate and ferrihydrite in G. sulfurreducens PCA probably by serving as a transcriptional repressor.

  5. Role of microbial Fe(III) reduction and solution chemistry in aggregation and settling of suspended particles in the Mississippi River Delta plain, Louisiana, USA

    Science.gov (United States)

    Jaisi, D.P.; Ji, S.; Dong, H.; Blake, R.E.; Eberl, D.D.; Kim, J.

    2008-01-01

    River-dominated delta areas are primary sites of active biogeochemical cycling, with productivity enhanced by terrestrial inputs of nutrients. Particle aggregation in these areas primarily controls the deposition of suspended particles, yet factors that control particle aggregation and resulting sedimentation in these environments are poorly understood. This study was designed to investigate the role of microbial Fe(III) reduction and solution chemistry in aggregation of suspended particles in the Mississippi Delta. Three representative sites along the salinity gradient were selected and sediments were collected from the sediment-water interface. Based on quantitative mineralogical analyses 88-89 wt.% of all minerals in the sediments are clays, mainly smectite and illite. Consumption of SO421 and the formation of H2S and pyrite during microbial Fe(III) reduction of the non-sterile sediments by Shewanella putrefaciens CN32 in artificial pore water (APW) media suggest simultaneous sulfate and Fe(III) reduction activity. The pHPZNPC of the sediments was ??? 3.5 and their zeta potentials at the sediment-water interface pH (6.9-7.3) varied from -35 to -45 mV, suggesting that both edges and faces of clay particles have negative surface charge. Therefore, high concentrations of cations in pore water are expected to be a predominant factor in particle aggregation consistent with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Experiments on aggregation of different types of sediments in the same APW composition revealed that the sediment with low zeta potential had a high rate of aggregation. Similarly, addition of external Fe(II) (i.e. not derived from sediments) was normally found to enhance particle aggregation and deposition in all sediments, probably resulting from a decrease in surface potential of particles due to specific Fe(II) sorption. Scanning and transmission electron microscopy (SEM, TEM) images showed predominant face-to-face clay aggregation in native

  6. Study of the kinetics of the transport of Cu(II), Cd(II) and Ni(II) ions through a liquid membrane

    Energy Technology Data Exchange (ETDEWEB)

    Granado-Castro, Maria D.; Galindo-Riano, Maria D.; Garcia-Vargas, M. [University of Cadiz, Department of Analytical Chemistry, Faculty of Sciences, Puerto Real, Cadiz (Spain); Dominguez-Lledo, F.C.; Diaz-Lopez, C. [University of La Havana, Department of Analytical Chemistry, Faculty of Chemistry, La Havana, CP (Cuba)

    2008-06-15

    The coupled transport of Cu(II), Cd(II) and Ni(II) ions through a bulk liquid membrane (BLM) containing pyridine-2-acetaldehyde benzoylhydrazone (2-APBH) as carrier dissolved in toluene has been studied. Once the optimal conditions of extraction of each metal were established, a comparative study of the transport kinetics for these metals was performed by means of a kinetic model involving two consecutive irreversible first-order reactions. The kinetic parameters apparent rate constants of the metal extraction and re-extraction reactions (k{sub 1}, k{sub 2}), the maximum reduced concentration of the metal in the liquid membrane (R{sup max}{sub o}), the time of the maximum value of R{sub o} (t{sub max}) and the maximum entry and exit fluxes of the metal through the liquid membrane (J{sup max}{sub f} and J{sup max}{sub s}) of the extraction and stripping reactions were evaluated and results showed good agreement between experimental data and theoretical predictions. Complete transport through the membrane took place according to the following order: Cd(II)>Cu(II)>Ni(II), with similar kinetic parameters obtained for Cu(II) and Cd(III). The transport behaviour of Ni(II) was different to that of Cu(II) and Cd(III), probably due to the different stoichiometry of the nickel complex compared to those of the other metal ions and the different chemical conditions required for its formation. The influence of the sample salinity on the transport kinetics was studied. k{sub 1} values decreased slightly when the feed solution salinity was increased for Cu(II) and Ni(II), but not for Cd(II). Values of k{sub 2} were practically unaffected. The proposed BLM was applied to the preconcentration and separation of metal ions (prior to their determination) in water samples with different saline matrices (CRM, river water and seawater), and good agreement with the certified values was obtained. (orig.)

  7. Supramolecular architectures in luminescent Zn(II) and Cd(II) complexes containing imidazole derivatives: Crystal structures, vibrational and thermal properties, Hirshfeld surface analysis and electrostatic potentials

    Science.gov (United States)

    Di Santo, Alejandro; Echeverría, Gustavo A.; Piro, Oscar E.; Pérez, Hiram; Ben Altabef, Aida; Gil, Diego M.

    2017-04-01

    Three novel zinc and cadmium complexes with 1-methylimidazole and 2-methylimidazole as ligands, mono-nuclear dichloro-bis(1-methylimidazole) zinc(II) and dibromo-bis(2-methylimidazole)cadmium(II) monohydrate complexes, and poly-nuclear bis(1-methylimidazole)-di-(μ2-bromo)cadmium(II) complex, namely, compounds 1-3, respectively, have been synthesized. The complexes were characterized by IR and Raman spectroscopies, thermal analysis and fluorescence. All the compounds exhibit interesting luminescent properties in solid state originated from intra-ligand (π→π*) transitions. Crystal structures of 1-3 were determined by single-crystal X-ray diffraction. Compound 1 crystallizes in P21/n space group, the Zn(II) ion lies at a crystal general position in a tetrahedral environment, and the mono-nuclear units are weakly bonded to one another by Csbnd H⋯Cl hydrogen bonds. Compound 2 crystallizes in Pnma space group, and mirror-related tetrahedral units around Cd(II) ion are H-bonded through a water molecule. Compound 3 crystallizes in P21/c space group, and the Cd(II) ion presents a centrosymmetric octahedral coordination. Neighboring and equatorial edge-sharing octahedra conform a polymeric arrangement that extends along the crystal a-axis. Weak hydrogen bonds are the major driving forces in the crystal packing of the three complexes. Hirshfeld surface analysis reveals a detailed scrutiny of intermolecular interactions experienced by each complex. The surfaces mapped over dnorm property highlight the X···H (X = Cl, Br) as the main intermolecular contacts for the three complexes, being also relevant the presence of O⋯H contacts for complex 2. The surfaces mapped over Shape index and curvedness properties for the two Cd complexes allow identify π … π stacking interactions which are absent in the Zn complex. 2D fingerprint plots have been used to quantify the relative contribution of the intermolecular contacts to crystal stability of compounds, showing

  8. Extraction and separation of Nd(III), Sm(III), Dy(III), Fe(III), Ni(II), and Cs(I) from concentrated chloride solutions with N,N,N',N'-tetra(2-ethylhexyl) diglycolamide as new extractant

    Institute of Scientific and Technical Information of China (English)

    E.A. Mowafy; D. Mohamed

    2015-01-01

    The feasibility of using N,N,N',N'-tetra(2-ethylhexyl)diglycolamide (TEHDGA) in 75 vol.% n-dodecane-25 vol.% n-octanol as agents for the extraction and separation of Nd(III), Sm(III), Dy(III), Fe(III), Ni(II), and Cs(I) from concentrated chlo-ride solution was investigated. Different extraction behaviors were obtained towards rare earth elements (REE) studied and Fe(III), Ni(II) and Cs(I). Efficient separation of Nd(III), Sm(III) and Dy(III) from Fe(III), Ni(II), and Cs(I) was achieved by TEHDGA, depending on the HCl, HNO3 or H2SO4 concentration. A systematic investigation was carried out on the detailed extraction prop-erties of Nd(III), Sm(III), and Dy(III) with TEHDGA from chloride media. The IR spectra of the extracted species were investi-gated.

  9. A Geobacter sulfurreducens strain expressing pseudomonas aeruginosa type IV pili localizes OmcS on pili but is deficient in Fe(III) oxide reduction and current production.

    Science.gov (United States)

    Liu, Xing; Tremblay, Pier-Luc; Malvankar, Nikhil S; Nevin, Kelly P; Lovley, Derek R; Vargas, Madeline

    2014-02-01

    The conductive pili of Geobacter species play an important role in electron transfer to Fe(III) oxides, in long-range electron transport through current-producing biofilms, and in direct interspecies electron transfer. Although multiple lines of evidence have indicated that the pili of Geobacter sulfurreducens have a metal-like conductivity, independent of the presence of c-type cytochromes, this claim is still controversial. In order to further investigate this phenomenon, a strain of G. sulfurreducens, designated strain PA, was constructed in which the gene for the native PilA, the structural pilin protein, was replaced with the PilA gene of Pseudomonas aeruginosa PAO1. Strain PA expressed and properly assembled P. aeruginosa PilA subunits into pili and exhibited a profile of outer surface c-type cytochromes similar to that of a control strain expressing the G. sulfurreducens PilA. Surprisingly, the strain PA pili were decorated with the c-type cytochrome OmcS in a manner similar to the control strain. However, the strain PA pili were 14-fold less conductive than the pili of the control strain, and strain PA was severely impaired in Fe(III) oxide reduction and current production. These results demonstrate that the presence of OmcS on pili is not sufficient to confer conductivity to pili and suggest that there are unique structural features of the G. sulfurreducens PilA that are necessary for conductivity.

  10. Acid–base equilibria of the Zn(II and Fe(III complexes with condensation products of 2-acetylpyridine and the dihydrazide of oxalic and malonic acid

    Directory of Open Access Journals (Sweden)

    DUŠAN SLADIĆ

    2009-03-01

    Full Text Available Acid–base equilibria of Zn(II and Fe(III complexes with N',N'2-bis[(1E-1-(2-pyridylethylidene]ethanedihydrazide (ligand L1 and N',N'2-bis[(1E-1-(2-pyridylethylidene]propanedihydrazide (ligand L2, i.e., [Fe(L1Cl2(H2O], [Fe(L2Cl(H2O]2+, [Zn(L1(H2O3]+ and [Zn(L2(H2O2]2+, which expressed cytotoxic activity, were investigated in aqueous media. The equilibrium constants were determined potentiometrically at 25 °C at a constant ionic strength of 0.10 mol/dm3 (Na2SO4. The results showed that at pH < 8 both the Fe(III complexes studied here have three, while [Zn(L1(H2O3]+ and [Zn(L2(H2O2]2+ have one and two titratable protons, respectively. Based on the obtained values for the equilibrium constants, protonation schemes of the examined complexes are proposed.

  11. Effect of Fe(III) on 1,1,2,2-tetrachloroethane degradation and vinyl chloride accumulation in wetland sediments of the Aberdeen proving ground

    Science.gov (United States)

    Jones, E.J.P.; Voytek, M.A.; Lorah, M.M.

    2004-01-01

    1,1,2,2-Tetrachloroethane (TeCA) contaminated groundwater at the Aberdeen Proving Ground discharges through an anaerobic wetland in West Branch Canal Creek, MD, where dechlorination occurred. Two microbially mediated pathways, dichloroelimination and hydrogenolysis, account for most of the TeCA degradation at this site. The dichloroelimination pathways led to the formation of vinyl chloride (VC), a recalcitrant carcinogen of great concern. The effect of adding Fe(III) to TeCA-amended microcosms of wetland sediment was studied. Differences were identified in the TeCA degradation pathway between microcosms treated with amorphous ferric oxyhydroxide (AFO-treated) and untreated (no AFO) microcosms. TeCA degradation was accompanied by a lower accumulation of VC in AFO-treated microcosms than no AFO microcosms. The microcosm incubations and subsequent experiments with the microcosm materials showed that AFO treatment resulted in lower production of VC by shifting TeCA degradation from dichloroelimination pathways to production of a greater proportion of chlorinated ethane products, and decreasing the microbial capability to produce VC from 1,2-dichloroethylene. VC degradation was not stimulated in the presence of Fe(III). Rather, VC degradation occurred readily under methanogenic conditions and was inhibited under Fe(III)-reducing conditions.

  12. Synthesis, spectroscopic, thermal and anticancer studies of metal-antibiotic chelations: Ca(II), Fe(III), Pd(II) and Au(III) chloramphenicol complexes

    Science.gov (United States)

    Al-Khodir, Fatima A. I.; Refat, Moamen S.

    2016-09-01

    Four Ca(II), Fe(III), Pd(II) and Au(III) complexes of chloramphenicol drug have been synthesized and well characterized using elemental analyses, (infrared, electronic, and 1H-NMR) spectra, magnetic susceptibility measurement, and thermal analyses. Infrared spectral data show that the chloramphenicol drug coordinated to Ca(II), Pd(II) and Au(III) metal ions through two hydroxyl groups with 1:1 or 1:2 M ratios, but Fe(III) ions chelated towards chloramphenicol drug via the oxygen and nitrogen atoms of amide group with 1:2 ratio based on presence of keto↔enol form. The X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques were used to identify the nano-size particles of both iron(III) and gold(III) chloramphenicol complexes. The antimicrobial assessments of the chloramphenicol complexes were scanned and collected the results against of some kind of bacteria and fungi. The cytotoxic activity of the gold(III) complex was tested against the human colon carcinoma (HCT-116) and human hepatocellular carcinoma (HepG-2) tumor cell lines.

  13. Electron transfer and atom exchange between aqueous Fe(II) and structural Fe(III) in clays. Role in U and Hg(II) transformations

    Energy Technology Data Exchange (ETDEWEB)

    Scherer, Michelle [Univ. of Iowa, Iowa City, IA (United States)

    2016-08-31

    During this project, we investigated Fe electron transfer and atom exchange between aqueous Fe(II) and structural Fe(III) in clay minerals. We used selective chemical extractions, enriched Fe isotope tracer experiments, computational molecular modeling, and Mössbauer spectroscopy. Our findings indicate that structural Fe(III) in clay minerals is reduced by aqueous Fe(II) and that electron transfer occurs when Fe(II) is sorbed to either basal planes and edge OH-groups of clay mineral. Findings from highly enriched isotope experiments suggest that up to 30 % of the Fe atoms in the structure of some clay minerals exhanges with aqueous Fe(II). First principles calculations using a small polaron hopping approach suggest surprisingly fast electron mobility at room temperature in a nontronite clay mineral and are consistent with temperature dependent Mössbauer data Fast electron mobility suggests that electrons may be able to conduct through the mineral fast enough to enable exchange of Fe between the aqueous phase and clay mineral structure. over the time periods we observed. Our findings suggest that Fe in clay minerals is not as stable as previously thought.

  14. Binding of the Trace Elements: Cu(II) and Fe(III) to the Native and Modified Nutritive Potato Starches Studied by EPR

    Science.gov (United States)

    Śmigielska, H.; Lewandowicz, G.; Goslar, J.; Hoffmann, S. K.

    2006-08-01

    The Cu(II) and Fe(III) ions have been adsorbed by four potato starches of different degrees of oxidation (different numbers of COOH groups replacing host CH2OH groups): native (no oxidized), white (pudding) with oxidation degree of 0.04%, gelating (0.1%), and LUBOX starch (0.5%). Concentration of the ions in starches was determined from atomic absorption and EPR spectrum intensity. For small concentration of the adsorbed ions (below 4 mg/g) nearly all ions are adsorbed from the solution. EPR shows that adsorbed copper(II) ions are chemically bonded to the starch molecules (preferably) at COOH sites and uniformly dispersed in the starch structure. The complexes are typical of octahedral or square-quadratic coordination with spin-Hamiltonian parameters gǁ=2.373, g⊥= 2.080, Aǁ=12.1 mT, A⊥=1.0 mT. For higher concentrations the Cu(II) displays a tendency to clustering. Iron(III) ions are introduced into starch in a form of clusters mainly, even for the smallest concentration. The highest concentrations of both Cu(II) and Fe(III) were observed in LUBOX starch having the highest degree of oxidation.

  15. INVESTIGATION OF THE TRANSFORMATION OF URANIUM UNDER IRON-REDUCING CONDITIONS: REDUCTION OF UVI BY BIOGENIC FEII/FEIII HYDROXIDE (GREEN RUST)

    Energy Technology Data Exchange (ETDEWEB)

    O' Loughlin, Edward J.; Scherer, Michelle M.; Kemner, Kenneth M.

    2006-12-31

    The recent identification of green rusts (GRs) as products of the reduction of FeIII oxyhydroxides by dissimilatory iron-reducing bacteria, coupled with the ability of synthetic (GR) to reduce UVI species to insoluble UO2, suggests that biogenic green rusts (BioGRs) may play an important role in the speciation (and thus mobility) of U in FeIII-reducing environments. The objective of our research was to examine the potential for BioGR to affect the speciation of U under FeIII-reducing conditions. To meet this objective, we designed and executed a hypothesis-driven experimental program to identify key factors leading to the formation of BioGRs as products of dissimilatory FeIII reduction, to determine the key factors controlling the reduction of UVI to UIV by GRs, and to identify the resulting U-bearing mineral phases. The results of this research significantly increase our understanding of the coupling of biotic and abiotic processes with respect to the speciation of U in iron-reducing environments. In particular, the reduction of UVI to UIV by BioGR with the subsequent formation of U-bearing mineral phases may be effective for immobilizing U in suboxic subsurface environments. This information has direct applications to contaminant transport modeling and bioremediation engineering for natural or enhanced in situ remediation of subsurface contamination.

  16. Synthesis, Characterization and DNA-Binding Properties of The Novel Mononuclear Zn(II, Cd(II, and Mn(II Complexes with Pantoprazole.

    Directory of Open Access Journals (Sweden)

    Wessam N. El-Sayed

    2016-04-01

    Full Text Available A   novel   mononuclear   Mn(II,   Zn(II   and   Cd(II   complexes of pantoprazole   (PA   was synthesized  and characterized  by elemental analysis,  molar conductivity,  magnetic susceptibility   measurements,   IR,  UV-visible  spectral  studies,  and  thermal  analysis.  The electronic spectra along with magnetic data suggest octahedral geometry for Mn(II, Zn(II and Cd(II complexes.  PA acts as an anionic bi-dentate ligand being coordinated by (S=O oxygen and benzimdazolyl nitrogen atoms. The interaction of the complexes with calf thymus DNA (CT-DNA was monitored by blue shift and hyperchromism in the UV-vis spectra. The observed  intrinsic  binding  constants  together  with  structural  analysis  of  the  complexes indicate  the groove  binding. The binding constants were determined at 303°K, 308°K and 313°K.  A thermodynamic analysis showed that the reaction is spontaneous with ΔG being negative. The enthalpy ΔH and the entropy ΔS of reactions were all determined.

  17. Removal of Cd(II), Zn(II) and Pb(II) from aqueous solutions by brown marine macro algae: kinetic modelling.

    Science.gov (United States)

    Freitas, Olga M M; Martins, Ramiro J E; Delerue-Matos, Cristina M; Boaventura, Rui A R

    2008-05-01

    Specific marine macro algae species abundant at the Portuguese coast (Laminaria hyperborea, Bifurcaria bifurcata, Sargassum muticum and Fucus spiralis) were shown to be effective for removing toxic metals (Cd(II), Zn(II) and Pb(II)) from aqueous solutions. The initial metal concentrations in solution were about 75-100 mg L(-1). The observed biosorption capacities for cadmium, zinc and lead ions were in the ranges of 23.9-39.5, 18.6-32.0 and 32.3-50.4 mg g(-1), respectively. Kinetic studies revealed that the metal uptake rate was rather fast, with 75% of the total amount occurring in the first 10 min for all algal species. Experimental data were well fitted by a pseudo-second order rate equation. The contribution of internal diffusion mechanism was significant only to the initial biosorption stage. Results indicate that all the studied macro algae species can provide an efficient and cost-effective technology for eliminating heavy metals from industrial effluents.

  18. Removal of Pb(II), Cu(II), and Cd(II) from aqueous solutions by biochar derived from KMnO4 treated hickory wood.

    Science.gov (United States)

    Wang, Hongyu; Gao, Bin; Wang, Shenseng; Fang, June; Xue, Yingwen; Yang, Kai

    2015-12-01

    In this work, a novel approach was developed to prepare an engineered biochar from KMnO4 treated hickory wood through slow pyrolysis (600°C). Characterization experiments with various tools showed that the engineered biochar surface was covered with MnOx ultrafine particles. In comparison to the pristine biochar, the engineered biochar also had more surface oxygen-containing functional groups and much larger surface area. Batch sorption experiments showed that the engineered biochar had strong sorption ability to Pb(II), Cu(II), and Cd(II) with maximum sorption capacities of 153.1, 34.2, and 28.1mg/g, respectively, which were significantly higher than that of the pristine biochar. Batch sorption experiments also showed that the dosage, initial solution pH, and ionic strength affected the removal of the heavy metals by the biochars. The removal of the metals by the engineered biochar was mainly through surface adsorption mechanisms involving both the surface MnOx particles and oxygen-containing groups.

  19. Removal of Cd(II), Zn(II) and Pb(II) from aqueous solutions by brown marine macro algae: Kinetic modelling

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Olga M.M. [LRSE - Laboratory of Separation and Reaction Engineering, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias 4200-465 Porto (Portugal); REQUIMTE, Instituto Superior de Engenharia do Porto, Rua Dr. Bernardino de Almeida 431 4200-072 Porto (Portugal); Martins, Ramiro J.E. [Departamento de Engenharia Quimica e Biologica, Escola Superior de Tecnologia, Instituto Politecnico de Braganca, Campus de Santa Apolonia, 5301-857 Braganca (Portugal); LRSE - Laboratory of Separation and Reaction Engineering, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias 4200-465 Porto (Portugal); Delerue-Matos, Cristina M. [REQUIMTE, Instituto Superior de Engenharia do Porto, Rua Dr. Bernardino de Almeida 431 4200-072 Porto (Portugal); Boaventura, Rui A.R. [Departamento de Engenharia Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); LRSE - Laboratory of Separation and Reaction Engineering, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias 4200-465 Porto (Portugal)], E-mail: bventura@fe.up.pt

    2008-05-01

    Specific marine macro algae species abundant at the Portuguese coast (Laminaria hyperborea, Bifurcaria bifurcata, Sargassum muticum and Fucus spiralis) were shown to be effective for removing toxic metals (Cd(II), Zn(II) and Pb(II)) from aqueous solutions. The initial metal concentrations in solution were about 75-100 mg L{sup -1}. The observed biosorption capacities for cadmium, zinc and lead ions were in the ranges of 23.9-39.5, 18.6-32.0 and 32.3-50.4 mg g{sup -1}, respectively. Kinetic studies revealed that the metal uptake rate was rather fast, with 75% of the total amount occurring in the first 10 min for all algal species. Experimental data were well fitted by a pseudo-second order rate equation. The contribution of internal diffusion mechanism was significant only to the initial biosorption stage. Results indicate that all the studied macro algae species can provide an efficient and cost-effective technology for eliminating heavy metals from industrial effluents.

  20. Photo-transformation of pedogenic humic acid and consequences for Cd(II), Cu(II) and Pb(II) speciation and bioavailability to green microalga.

    Science.gov (United States)

    Worms, Isabelle A M; Adenmatten, David; Miéville, Pascal; Traber, Jacqueline; Slaveykova, Vera I

    2015-11-01

    Humic substances (HS) play key role in toxic metal binding and protecting aquatic microorganisms from metal-induced stress. Any environmental changes that could alter HS concentration and reactivity can be expected to modify metal complexation and thus affect metal speciation and bioavailability to microalgae. The present study explores the influence of increased solar irradiance on the chemical structures and molecular weight of Elliott soil humic acid (EHA) and the associated consequences for Cd(II), Cu(II) and Pb(II) complexation and intracellular metal content in microalga. The results demonstrate that high radiance doses induce an oxidation of EHA with a formation of low molecular weight acids, an increase of -OH and -COOH group abundance, and a drop in EHA hydrodynamic size and molecular weight. The photo-induced structural changes are accompanied with a release of metal from M-EHA complexes and narrowing their size distribution, which in turn results in an increase of the intracellular Cd, Cu and Pb contents in microalga Chlamydomonas reinhardtii in agreement with the measured free metal ions concentrations.

  1. Synthesis, crystal structure and spectroscopy of bioactive Cd(II) polymeric complex of the non-steroidal anti-inflammatory drug diclofenac sodium: Antiproliferative and biological activity

    Science.gov (United States)

    Tabrizi, Leila; Chiniforoshan, Hossein; McArdle, Patrick

    2015-02-01

    The interaction of Cd(II) with the non-steroidal anti-inflammatory drug diclofenac sodium (Dic) leads to the formation of the complex [Cd2(L)41.5(MeOH)2(H2O)]n(L = Dic), 1, which has been isolated and structurally characterized by X-ray crystallography. Diclofenac sodium and its metal complex 1 have also been evaluated for antiproliferative activity in vitro against the cells of three human cancer cell lines, MCF-7 (breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma), and a mouse fibroblast L-929 cell line. The results of cytotoxic activity in vitro expressed as IC50 values indicated the diclofenac sodium and cadmium chloride are non active or less active than the metal complex of diclofenac (1). Complex 1 was also found to be a more potent cytotoxic agent against T-24 and MCF-7 cancer cell lines than the prevalent benchmark metallodrug, cisplatin, under the same experimental conditions. The superoxide dismutase activity was measured by Fridovich test which showed that complex 1 shows a low value in comparison with Cu complexes. The binding properties of this complex to biomolecules, bovine or human serum albumin, are presented and evaluated. Antibacterial and growth inhibitory activity is also higher than that of the parent ligand compound.

  2. Synthesis and X-ray structure analysis of a new binuclear Schiff base Co(II) complex with the ligand N,N'-bis(3-methoxysalicylidene)-1,4-butanediamine

    Energy Technology Data Exchange (ETDEWEB)

    Nasr-Esfahani, M., E-mail: m-nasresfahani@iaun.ac.ir [Islamic Azad University, Najafabad Branch, Department of Materials Science and Engineering (Iran, Islamic Republic of)

    2009-12-15

    The title binuclear complex, tris[N,N-bis(3-methoxysalicylidene)-1,4-diaminobutane] dicobalt(II), C{sub 60}H{sub 70}Co{sub 2}N{sub 6}O{sub 15}, was prepared by the reaction of the tetradentate Schiff base ligand bis(3-methoxysalicylidene)-1,4-diaminobutane and Co(CH{sub 3}COO){sub 2} . 4H{sub 2}O in a ethanol solution and structurally characterized by single-crystal X-ray diffraction. This complex has a dinuclear structure where two Co(II) ions are bridged by one N{sup 0},N'-bis(3-methoxysalicylidene)-1,4-diaminobutane. The two Co(II) ions, have two distorted octahedral coordination involving two O and two N atoms.

  3. On the Importance of Noncovalent Carbon-Bonding Interactions in the Stabilization of a 1D Co(II) Polymeric Chain as a Precursor of a Novel 2D Coordination Polymer.

    Science.gov (United States)

    Pal, Pampi; Konar, Saugata; Lama, Prem; Das, Kinsuk; Bauzá, Antonio; Frontera, Antonio; Mukhopadhyay, Subrata

    2016-07-14

    A new cobalt(II) coordination polymer 2 with μ1,5 dicyanamide (dca) and a bidentate ligand 3,5-dimethyl-1-(2'-pyridyl)pyrazole (pypz) is prepared in a stepwise manner using the newly synthesized one-dimensional linear Co(II) coordination polymer 1 as a precursor. The structural and thermal characterizations elucidate that the more stable complex 2 shows a two-dimensional layer structural feature. Here, Co(II) atoms with μ1,5 dicyanamido bridges are linked by the ligand pypz forming a macrocyclic chain that runs along the crystallographic 'c' axis having 'sql' (Shubnikov notation) net topology with a 4-connected uninodal node having point symbol {4(4).6(2)}. The remarkable noncovalent carbon-bonding contacts detected in the X-ray structure of compound 1 are analyzed and characterized by density functional theory calculations and the analysis of electron charge density (atoms in molecules).

  4. Isolation and characterization of the tertiary amine Alamine 304 hydrochioride. Its application on the extraction of Co(II, Au(III and Pt(IV

    Directory of Open Access Journals (Sweden)

    López-Delgado, Aurora

    2000-06-01

    Full Text Available Amine Alamine 304 dissolved in xylene reacts with hydrochloric acid to form the amine chloride (R3NH+Cl- and the amine dichloride (R3NH2Cl2. The former compound was isolated and characterized by chemical analysis, X-ray powder diffraction, infrared spectroscopy and scanning electron microscopy. Lattice parameters of the isolated amine chloride were determined and refined by least-square numerical treatment (monoclinic cell, with a = 29.017(4 Å, b = 14.564(7 Å, c = 5.043(1 Å, b = 95.68(3 ° and V = 2,120 Å3. The amine chloride is a potential anion-exchanger with metals, thus data on the liquid-liquid extraction of Co(II, Au(III and Pt(IV are also reported.

    La amina Alamine 304 disuelta en xileno reacciona con el ácido clorhídrico para formar el cloruro de la amina (R3NH+Cl- y el dicloruro de amina (R3NH2Cl2. El primero de estos compuestos se aisló y caracterizó mediante análisis químico, difracción de rayos X, espectroscopia de IR y microscopía electrónica de barrido. Se determinaron y refinaron los parámetros de red del cloruro de amina (monoclínico, a = 29,017(4 Å, b = 14,564(7 Å, c = 5,043(1 Å, b = 95,68(3 ° y V = 2.120 Å3. El cloruro de amina actúa como un intercambiador aniónico con ciertos metales, por lo que se incluyen datos sobre la extracción líquido-líquido de Co(II, Au(III y Pt(IV.

  5. New type of single chain magnet: pseudo-one-dimensional chain of high-spin Co(II) exhibiting ferromagnetic intrachain interactions.

    Science.gov (United States)

    Tangoulis, V; Lalia-Kantouri, M; Gdaniec, M; Papadopoulos, Ch; Miletic, V; Czapik, A

    2013-06-03

    Two new six-coordinated high-spin Co(II) complexes have been synthesized through the reactions of Co(II) salts with dipyridylamine (dpamH) and 5-nitro-salicylaldehyde (5-NO2-saloH) or 3-methoxy-salicylaldehyde (3-OCH3-saloH) under argon atmosphere: [Co(dpamH)2(5-NO2-salo)]NO3 (1) and [Co(dpamH)2(3-OCH3-salo)]NO3·1.3 EtOH·0.4H2O (2). According to the crystal packing of compound 1, two coordination cations are linked with two nitrate anions into a cyclic dimeric arrangement via N-H···O and C-H···O hydrogen bonds. In turn, these dimers are assembled into (100) layers through π-π stacking interactions between inversion-center related pyridine rings of the dpamH ligands. The crystal packing of compound 2 reveals a 1D assembly consisting solely from the coordination cations, which is formed by π-π stacking interactions between pyridine rings of one of the dpamH along the [010] and another 1D assembly of the coordination cations and nitrate anions through the N-H···O hydrogen-bonding interactions along the [001] direction. All complexes were magnetically characterized, and a new approximation method was used to fit the magnetic susceptibility data in the whole temperature range 2-300 K on the basis of an empirical expression which allows the treatment of each cobalt(II) ion in axial symmetry as an effective spin S(eff) = 1/2. In zero-field, dynamic magnetic susceptibility measurements show slow magnetic relaxation below 5.5 K for compound 2. The slow dynamics may originate from the motion of broad domain walls and is characterized by an Arrhenius law with a single energy barrier Δr/k(B) = 55(1) K for the [10-1488 Hz] frequency range. In order to reveal the importance of the crystal packing in the SCM behavior, a gentle heating process to 180 °C was carried out to remove the solvent molecules. The system, after heating, undergoes a major but not complete collapse of the network retaining to a small percentage its SCM character.

  6. Spectroscopic, magnetic and thermal studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes of 3-acetylcoumarin-isonicotinoylhydrazone and their antimicrobial and anti-tubercular activity evaluation

    Science.gov (United States)

    Hunoor, Rekha S.; Patil, Basavaraj R.; Badiger, Dayananda S.; Vadavi, Ramesh S.; Gudasi, Kalagouda B.; Chandrashekhar, V. M.; Muchchandi, I. S.

    2010-11-01

    Co(II), Ni(II), Cu(II) and Zn(II) complexes with a new heterocyclic Schiff base derived by the condensation of isonicotinoylhydrazide and 3-acetylcoumarin have been synthesized. 1H, 13C and 2D HETCOR NMR analyses confirm the formation of title compound and existence of the same in two isomeric forms. The metal complexes were characterized on the basis of various spectroscopic techniques like electronic, EPR, IR, 1H and 13C NMR studies, elemental analysis, magnetic properties and thermogravimetric analysis, and also by the aid of molar conductivity measurements. It is found that the Schiff base behaves as a monobasic tridentate ligand coordinating in the imidol form with 1:1 metal to ligand stoichiometry. Trigonal bipyramidal geometry has been assigned for Ni(II) and Cu(II) complexes, while tetrahedral for Co(II) and Zn(II) complexes. The compounds were subjected to antimicrobial and anti-tubercular activity screening using serial broth dilution method and Minimum Inhibitory Concentration (MIC) is determined. Zn(II) complex has shown significant antifungal activity with an MIC of 6.25 μg/mL while Cu(II) complex is noticeable for antibacterial activity at the same concentration. Anti-TB activity of the ligand has enhanced on complexation with Co(II) and Ni(II) ions.

  7. Application of Zr/Ti-Pic in the adsorption process of Cu(II), Co(II) and Ni(II) using adsorption physico-chemical models and thermodynamics of the process; Aplicacao de Zr/Ti-PILC no processo de adsorcao de Cu(II), Co(II) e Ni(II) utilizando modelos fisico-quimicos de adsorcao e termodinamica do processo

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, Denis Lima; Airoldi, Claudio [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Inorganica]. E-mail: dlguerra@iqm.unicamp.br; Lemos, Vanda Porpino; Angelica, Romulo Simoes [Universidade Federal do Para (UFPa), Belem (Brazil); Viana, Rubia Ribeiro [Universidade Federal do Mato Grosso (UFMT), Cuiaba (Brazil). Inst. de Ciencias Exatas e da Terra. Dept. de Recursos Minerais

    2008-07-01

    The aim of this investigation is to study how Zr/Ti-Pic adsorbs metals. The physico-chemical proprieties of Zr/Ti-Pic have been optimized with pillarization processes and Cu(II), Ni(II) and Co(II) adsorption from aqueous solution has been carried out, with maximum adsorption values of 8.85, 8.30 and 7.78 x-1 mmol g{sup -1}, respectively. The Langmuir, Freundlich and Temkin adsorption isotherm models have been applied to fit the experimental data with a linear regression process. The energetic effect caused by metal interaction was determined through calorimetric titration at the solid-liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant. (author)

  8. Mechanistic and energetic aspects of the thermal and photochemical redox chemistry of the octanuclear cubane complexes, Fe(III)(8)(mu(4)-O(4))(mu-pyrazolate)(12)X(4) (X = Cl or Br).

    Science.gov (United States)

    Ferraudi, Guillermo; Piñero, Dalice; Chakraborty, Indranil; Raptis, Raphael G; Lappin, A Graham; Berlin, Nicholas

    2010-05-13

    The mechanisms of the thermal and photochemical redox reactions of clusters [Fe(III)(8)(mu(4)-O(4))(mu-Pz)(12)X(4)] (Pz = pyrazolate anion, X = Cl or Br) were investigated in this work. Reactions of the complexes with e(-)(sol), C(*)H(2)OH, and several powerful reducing transition metal complexes were investigated using the pulse radiolysis technique. Reaction rates of the outer-sphere electron transfer reactions with transition metal complexes had to be rationalized by invoking the formation of a [Fe(III)(7)Fe(II) '(mu(4)-O(4))(mu-Pz)(12)X(4)](-) intermediate or excited state. A transient species observed in the reaction of the e(-)(sol) with the cubanes can be either an excited state or a reaction intermediate mediating the formation of the stable product, [Fe(III)(7)Fe(II)(mu(4)-O(4))(mu-Pz)(12)X(4)](-). Photoredox reactions, characteristic of the ligand X(-) to Fe(III) charge transfer excited sates, were observed in the 350 nm steady state and 351 nm laser flash irradiations of the cubanes. Quantum yields are limited by the rapid recombination of the photofragments. The charge transfer spectroscopy of the products was rationalized on the basis of parameters derived from the thermal electron transfer reactions.

  9. Simultaneous determination of trace Cd(II), Pb(II) and Cu(II) by differential pulse anodic stripping voltammetry using a reduced graphene oxide-chitosan/poly-l-lysine nanocomposite modified glassy carbon electrode.

    Science.gov (United States)

    Guo, Zhuo; Li, Dong-di; Luo, Xian-Ke; Li, Ya-Hui; Zhao, Qi-Nai; Li, Meng-Meng; Zhao, Yang-Ting; Sun, Tian-Shuai; Ma, Chi

    2017-03-15

    The reduced graphene oxide (RGO) and Chitosan (CS) hybrid matrix RGO-CS were coated onto the glassy carbon electrode (GCE) surface, then, poly-l-lysine films (PLL) were prepared by electropolymerization with cyclic voltammetry (CV) method to prepare RGO-CS/PLL modified glassy carbon electrode (RGO-CS/PLL/GCE) for the simultaneous electrochemical determination of heavy metal ions Cd(II), Pb(II) and Cu(II). Combining the advantageous features of RGO and CS, RGO and CS are used together because the positively charged CS can interact with the negatively changed RGO to prevent their aggregation. Furthermore, CS has many amino groups along its macromolecular chains and possessed strongly reactive with metal ions. Moreover, PLL modified electrodes have good stability, excellent permselectivity, more active sites and strong adherence to electrode surface, which enhanced electrocatalytic activity. The RGO-CS/PLL/GCE was characterized voltammetrically using redox couples (Fe(CN)6(3-/4-)), complemented with electrochemical impedance spectroscopy (EIS). Differential pulse anodic stripping voltammetry (DPASV) has been used for the detection of Cd(II), Pb(II) and Cu(II). The detection limit of RGO-CS/PLL/GCE toward Cd(II), Pb(II) and Cu(II) is 0.01μgL(-1), 0.02μgL(-1) and 0.02μgL(-1), respectively. The electrochemical parameters that exert influence on deposition and stripping of metal ions, such as supporting electrolytes, pH value, deposition potential, and deposition time, were carefully studied.

  10. Co(II), Ni(II) and Cu(II) complexes with coumarin-8-yl Schiff-bases: spectroscopic, in vitro antimicrobial, DNA cleavage and fluorescence studies.

    Science.gov (United States)

    Patil, Sangamesh A; Unki, Shrishila N; Kulkarni, Ajaykumar D; Naik, Vinod H; Badami, Prema S

    2011-09-01

    A new series of Co(II), Ni(II) and Cu(II) complexes of the type ML·2H2O of Schiff-bases derived from m-substituted thiosemicarbazides and 8-acetyl-7-hydroxy-4-methylcoumarin have been synthesized and characterized by spectroscopic studies. Schiff-bases exhibit thiol-thione tautomerism wherein sulphur plays an important role in the coordination. The coordination possibility of the Schiff-bases towards metal ions have been proposed in the light of elemental analyses, spectral (IR, UV-vis, FAB-mass, ESR and fluorescence), magnetic and thermal studies. The low molar conductance values in DMF indicate that, the metal complexes are non-electrolytes. The cyclic voltammetric studies suggested that, the Cu(II) and Ni(II) complexes are of single electron transfer quasi-reversible nature. The Schiff-bases and its metal complexes have been evaluated for their in vitro antibacterial (Escherichia coli, Staphilococcus aureus, Bascillus subtilis and Salmonella typhi) and antifungal activities (Candida albicans, Cladosporium and Aspergillus niger) by MIC method. The Schiff-base I and its metal complexes exhibited DNA cleavage activity on isolated DNA of A. niger.

  11. Molecular systematics and phylogeography of Cebus capucinus (Cebidae, Primates) in Colombia and Costa Rica by means of the mitochondrial COII gene.

    Science.gov (United States)

    Ruiz-Garcia, Manuel; Castillo, Maria Ignacia; Ledezma, Andrea; Leguizamon, Norberto; Sánchez, Ronald; Chinchilla, Misael; Gutierrez-Espeleta, Gustavo A

    2012-04-01

    We propose the first molecular systematic hypothesis for the origin and evolution of Cebus capucinus based on an analysis of 710 base pairs (bp) of the cytochrome c oxidase subunit II (COII) mitochondrial gene in 121 C. capucinus specimens sampled in the wild. The animals came from the borders of Guatemala and Belize, Costa Rica, and eight different departments of Colombia (Antioquia, Chocó, Sucre, Bolivar, Córdoba, Magdalena, Cauca, and Valle del Cauca). Three different and significant haplotype lineages were found in Colombia living sympatrically in the same departments. They all presented high levels of gene diversity but the third Colombian gene pool was determined likely to be the most ancestral lineage. The second Colombian mitochondrial (mt) haplogroup is likely the source of origin of the unique Central America mt haplogroup that was detected. Our molecular population genetics data do not agree with the existence of two well-defined subspecies in Central America (limitaneus and imitator). This Central America mt haplogroup showed significantly less genetic diversity than the Colombian mt haplogroups. All the C. capucinus analyzed showed evidence of historical population expansions. The temporal splits among these four C. capucinus lineages were related to the completion of the Panamanian land bridge as well as to climatic changes during the Quaternary Period.

  12. MtDNA COI-COII marker and drone congregation area: an efficient method to establish and monitor honeybee (Apis mellifera L.) conservation centres.

    Science.gov (United States)

    Bertrand, Bénédicte; Alburaki, Mohamed; Legout, Hélène; Moulin, Sibyle; Mougel, Florence; Garnery, Lionel

    2015-05-01

    Honeybee subspecies have been affected by human activities in Europe over the past few decades. One such example is the importation of nonlocal subspecies of bees which has had an adverse impact on the geographical repartition and subsequently on the genetic diversity of the black honeybee Apis mellifera mellifera. To restore the original diversity of this local honeybee subspecies, different conservation centres were set up in Europe. In this study, we established a black honeybee conservation centre Conservatoire de l'Abeille Noire d'Ile de France (CANIF) in the region of Ile-de-France, France. CANIF's honeybee colonies were intensively studied over a 3-year period. This study included a drone congregation area (DCA) located in the conservation centre. MtDNA COI-COII marker was used to evaluate the genetic diversity of CANIF's honeybee populations and the drones found and collected from the DCA. The same marker (mtDNA) was used to estimate the interactions and the haplotype frequency between CANIF's honeybee populations and 10 surrounding honeybee apiaries located outside of the CANIF. Our results indicate that the colonies of the conservation centre and the drones of the DCA show similar stable profiles compared to the surrounding populations with lower level of introgression. The mtDNA marker used on both DCA and colonies of the conservation centre seems to be an efficient approach to monitor and maintain the genetic diversity of the protected honeybee populations.

  13. Supramolecular complexes of Co(II), Ni(II) and Zn(II) p-hydroxybenzoates with caffeine: Synthesis, spectral characterization and crystal structure

    Science.gov (United States)

    Taşdemir, Erdal; Özbek, Füreya Elif; Sertçelik, Mustafa; Hökelek, Tuncer; Çelik, Raziye Çatak; Necefoğlu, Hacali

    2016-09-01

    Three novel complexes Co(II), Ni(II) and Zn(II) containing p-hydroxybenzoates and caffeine ligands were synthesized and characterized by elemental analysis, FT-IR and UV-vis Spectroscopy, molar conductivity and single crystal X-ray diffraction methods. The thermal properties of the synthesized complexes were investigated by TGA/DTA. The general formula of the complexes is [M(HOC6H4COO)2(H2O)4]·2(C8H10N4O2)·8H2O (where: M: Co, Ni and Zn). The IR studies showed that carboxylate groups of p-hydroxybenzoate ligands have monodentate coordination mode. The M2+ ions are octahedrally coordinated by two p-hydroxybenzoate ligands, four water molecules leading to an overall MO6 coordination environment. The medium-strength hydrogen bondings involving the uncoordinated caffeine ligands and water molecules, coordinated and uncoordinated water molecules and p-hydroxybenzoate ligands lead to three-dimensional supramolecular networks in the crystal structures.

  14. DNA binding and biological activity of mixed ligand complexes of Cu(II, Ni(II and Co(II with quinolones and N donor ligand

    Directory of Open Access Journals (Sweden)

    S.M M Akram

    2015-10-01

    Full Text Available  AbstractMixed ligand complexes of  Cu(II, Ni(II and Co(II have been synthesized by using levofloxacin and bipyridyl and characterized using spectral and analytical techniques. The binding behavior of the Ni(II and Cu(II complexes with herring sperm DNA(Hs-DNA were determined using electronic absorption titration, viscometric measurements and cyclic voltammetry measurements. The binding constant calculated  for Cu(II and Ni(II complexes are 2.0 x 104 and 4.0 x 104 M-1 respectively. Detailed analysis reveals that these metal complexes interact with DNA through intercalative binding mode. The nuclease activity of  Cu(II and Ni(II complexes with ct-DNA was carried out using agarose gel electrophoresis technique. The antioxidant activities for the synthesized complexes have been tested and the antibacterial activity for Ni(II complex was also checked.Key words: Intercalation, hypochromism, red shift and  peak potential.

  15. Synthesis, physico-chemical investigations of Co(II), Ni(II) and Cu(II) complexes and their in vitro microbial, cytotoxic, DNA cleavage studies.

    Science.gov (United States)

    Bagihalli, Gangadhar B; Patil, Sangamesh A

    2010-06-01

    A series of metal complexes of cobalt(II), nickel(II), and copper(II) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 2-amino-4-phenyl-1,3-thiazole with 8-formyl-7-hydroxy- 4-methylcoumarin. The probable structure of the complexes has been proposed on the basis of analytical and spectroscopic data (IR, UV-Vis, ESR, FAB-mass, and thermoanalytical). Electrochemical study of the complexes is also reported. Elemental analysis of the complexes confined them to stoichiometry of the type ML(2).2H(2)O [M = Co(II), Ni(II), and Cu(II)]. The Schiff base and its metal(II) complexes have been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes, and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus, and Cladosporium) by the MIC method. The brine shrimp bioassay was carried out to study their in vitro cytotoxic properties, and also the Schiff base and its metal(II) complexes have been studied for DNA cleavage.

  16. Biosorption of Ni(II, Cr(III, and Co(II from Solutions Using Acalypha hispida Leaf: Kinetics, Equilibrium, and Thermodynamics

    Directory of Open Access Journals (Sweden)

    Adesola Babarinde

    2013-01-01

    Full Text Available Biosorption studies were conducted to study the removal of Ni(II, Cr(III, and Co(II from aqueous solution of Acalypha hispida leaf. The FTIR spectral characteristics of Acalypha hispida leaf revealed the presence of ioniazable groups that could participate in the binding of metal ions in solution. The kinetic, equilibrium, and thermodynamic studies of the biosorption of the metal ions were investigated using various physicochemical parameters; each parameter was found to affect the biosorption process. The kinetic studies showed that the biosorption process was best represented by pseudo-second-order kinetics among four kinetic models tested. Equilibrium data were better represented by Freundlich isotherm among Langmuir and Freundlich adsorption isotherms. The study on the effect of dosage showed that the dosage of the biomass significantly affected the uptake of the metal ions from solution. Thermodynamic parameters such as standard Gibbs-free energy (, standard enthalpy (, standard entropy (, and the activation energy were calculated. The order of spontaneity of the biosorption process was found to be Cr(III > Ni(II > Co(II. The activation energy for the biosorption of each of the metal ions was less than 42 kJmol−1 at 323 K indicating that each was a diffusion-controlled process.

  17. Synthesis, Physico-Chemical and Antimicrobial Properties of Co(II, Ni(II, and Cu(II Mixed-Ligand Complexes of Dimethylglyoxime

    Directory of Open Access Journals (Sweden)

    A.A. Osunlaja

    2011-11-01

    Full Text Available The synthesis of non-electrolyte mixed-ligand complexes of the general formula [M(HdmgB], where M = Co(II, Ni(II or Cu(II Hdmg = dimethylglyoximato monoanion, B = 2- aminophenol(2-aph, diethylamine (dea or malonic acid (MOH are described. Metal analysis, melting points, solubility, conductivity, IR and UV/Visible electronic spectra were used in determining their physico-chemical properties. The antimicrobial activities of the complexes were tested against Esherichia coli, Staphylococcus aureus, Aspergillus niger and Aspergillus flavus. The complexes melted/decomposed at 120-306ºC and, most of them dissolved only in polar solvents. The colours of the complexes are mostly dark - brown or red. The spectral results suggest the binding of Hdmg, 2-amino phenol or malonic acid through the N atom and O atoms respectively to the metal ion In the electronic spectra of the complexes, the absorption bands observed in the UV/Visible region are presumed to be either due to charge transfer or intra-ligand transitions from the ligands or d-d transitions from the metal ions. The complexes showed marked antimicrobial activity against the tested microbes at 10 mg/mL. The possible use of the complexes as chemotherapeutic agents is hereby suggested.

  18. Oxygen Activation by Co(II) and a Redox Non-Innocent Ligand: Spectroscopic Characterization of a Radical-Co(II)-Superoxide Complex with Divergent Catalytic Reactivity.

    Science.gov (United States)

    Corcos, Amanda R; Villanueva, Omar; Walroth, Richard C; Sharma, Savita K; Bacsa, John; Lancaster, Kyle M; MacBeth, Cora E; Berry, John F

    2016-02-17

    Bimetallic (Et4N)2[Co2(L)2], (Et4N)2[1] (where (L)(3-) = (N(o-PhNC(O)(i)Pr)2)(3-)) reacts with 2 equiv of O2 to form the monometallic species (Et4N)[Co(L)O2], (Et4N)[3]. A crystallographically characterized analog (Et4N)2[Co(L)CN], (Et4N)2[2], gives insight into the structure of [3](1-). Magnetic measurements indicate [2](2-) to be an unusual high-spin Co(II)-cyano species (S = 3/2), while IR, EXAFS, and EPR spectroscopies indicate [3](1-) to be an end-on superoxide complex with an S = 1/2 ground state. By X-ray spectroscopy and calculations, [3](1-) features a high-spin Co(II) center; the net S = 1/2 spin state arises after the Co electrons couple to both the O2(•-) and the aminyl radical on redox non-innocent (L(•))(2-). Dianion [1](2-) shows both nucleophilic and electrophilic catalytic reactivity upon activation of O2 due to the presence of both a high-energy, filled O2(-) π* orbital and an empty low-lying O2(-) π* orbital in [3](1-).

  19. Microwave Synthesis, Spectral, Thermal and Antimicrobial Studies of Some Co(II, Ni(II and Cu(II Complexes Containing 2-Aminothiazole Moiety

    Directory of Open Access Journals (Sweden)

    A. P. Mishra

    2012-01-01

    Full Text Available Some new Schiff base metal complexes of Co(II, Ni(II and Cu(II derived from 4-chlorobenzylidene-2-aminothiazole (CAT and 2-nitrobenzylidene-2-aminothiazole (NAT have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, FT-IR, FAB-mass, molar conductance, electronic spectra, ESR, magnetic susceptibility, thermal, electrical conductivity and XRD analysis. The complexes are coloured and stable in air. Analytical data revealed that all the complexes exhibited 1:2 (metal:ligand ratio with coordination number 4 or 6. FAB-mass and thermal data show degradation pattern of the complexes. The thermal behavior of metal complexes shows that the hydrated complexes loses water molecules of hydration in the first step; followed by decomposition of ligand molecules in the subsequent steps. The crystal system, lattice parameter, unit cell volume and number of molecules in unit cell in the lattice of complexes have been determined by XRD analysis. XRD patterns indicate crystalline nature for the complexes. The solid state electrical conductivity of the metal complexes has also been measured. Solid state electrical conductivity studies reflect semiconducting nature of the complexes. The Schiff base and metal complexes show a good activity against the Gram-positive bacteria; Staphylococcus aureus and Gram-negative bacteria; Escherichia coli and fungi Aspergillus niger and Candida albicans.

  20. In situ generation of Co(II) by use of a solid-phase reactor in an FIA assembly for the spectrophotometric determination of penicillamine.

    Science.gov (United States)

    Corominas, B Gómez-Taylor; Pferzschner, Julia; Icardo, M Catalá; Zamora, L Lahuerta; Martínez Calatayud, J

    2005-09-01

    A flow injection analysis (FIA) manifold for the determination of penicillamine in pharmaceutical preparations is proposed. The manifold includes a solid-phase reactor for the in situ production of the derivatizing reagent, Co(II) ion, which forms a coloured complex with penicillamine in an alkaline medium. The reactor is prepared by natural immobilization of cobalt carbonate on a polymer matrix, which endows it with a high mechanical and microbiological stability. The cobalt released by passage of a 5 x 10(-4) mol l(-1) sulphuric acid stream at a flow-rate of 2.3 ml min(-1) is merged with a volume of 314 microl of sample containing penicillamine in ammonium-ammonia buffer at pH 9.5 to measure the absorbance at 360 nm. Beer's law is obeyed over the penicillamine concentration range 5-60 mg l(-1). The limit of detection (LOD) of the method is 1 mg l(-1) and its throughput 70 samples h(-1).

  1. Synthesis and characterization of Cu(II), Co(II) and Ni(II) complexes of a number of sulfadrug azodyes and their application for wastewater treatment

    Science.gov (United States)

    El-Baradie, K.; El-Sharkawy, R.; El-Ghamry, H.; Sakai, K.

    2014-03-01

    The azodye ligand (HL1) was synthesized from the coupling of sulfaguanidine diazonium salt with 2,4-dihydroxy-benzaldehyde while the two ligands, HL2 and HL3, were prepared by the coupling of sulfadiazine diazonium salt with salicylaldehyde (HL2) and 2,4-dihydroxy-benzaldehyde (HL3). The prepared ligands were characterized by elemental analysis, IR, 1H NMR and mass spectra. Cu(II), Co(II) and Ni(II) complexes of the prepared ligands have been synthesized and characterized by various spectroscopic techniques like IR, UV-Visible as well as magnetic and thermal (TG and DTA) measurements. It was found that all the ligands behave as a monobasic bidentate which coordinated to the metal center through the azo nitrogen and α-hydroxy oxygen atoms in the case of HL1 and HL3. HL2 coordinated to the metal center through sulfonamide oxygen and pyrimidine nitrogen. The applications of the prepared complexes in the oxidative degradation of indigo carmine dye exhibited good catalytic activity in the presence of H2O2 as an oxidant. The reactions followed first-order kinetics and the rate constants were determined. The degradation reaction involved the catalytic action of the azo-dye complexes toward H2O2 decomposition, which can lead to the generation of HOrad radicals as a highly efficient oxidant attacking the target dye. The detailed kinetic studies and the mechanism of these catalytic reactions are under consideration in our group.

  2. Zeolite-Y entrapped Ru(III and Fe(III complexes as heterogeneous catalysts for catalytic oxidation of cyclohexane reaction

    Directory of Open Access Journals (Sweden)

    Chetan K. Modi

    2017-02-01

    Full Text Available Catalysis is probably one of the greatest contributions of chemistry to both economic growth and environmental protection. Herein we report the catalytic behavior of zeolite-Y entrapped Ru(III and Fe(III complexes with general formulae [M(VTCH2·2H2O]+-Y and [M(VFCH2·2H2O]+-Y [where, VTCH = vanillin thiophene-2-carboxylic hydrazone and VFCH = vanillin furoic-2-carboxylic hydrazone] over the oxidation of cyclohexane forming cyclohexanone and cyclohexanol. The samples were corroborated by various physico-chemical techniques. These zeolite-Y based complexes are stable and recyclable under current reaction conditions. Amongst them, [Ru(VTCH2⋅2H2O]+-Y showed higher catalytic activity (41.1% with cyclohexanone (84.6% selectivity.

  3. Green oxidation of alkenes in ionic liquid solvent by hydrogen peroxide over high performance Fe(III) Schiff base complexes immobilized on MCM-41

    Indian Academy of Sciences (India)

    Mohammad Taghi Goldani; Ali Mohammadi; Reza Sandaroos

    2014-05-01

    A series of Fe(III) Schiff base complexes immobilized on MCM-41 were prepared and characterized by various physicochemical and spectroscopic methods. The complexes were used for oxidation of cyclohexene by 30% hydrogen peroxide in the presence and absence of ethylmethyl imidazolium chloride (EMIM) ionic liquid as solvent. The immobilized complexes proved to be effective catalysts and generally exhibited much higher catalytic performance than their homogeneous analogue. Catalytic performance of the complexes was also found to be closely related to the Schiff base ligands used. Additionally, ion liquid solvent efficiently improved all the catalytic performances. Finally, the reaction was extended to different alkenes using the heterogeneous complex 2-L4. Among all the alkenes, those containing -electron-withdrawing groups and trans-orientations exhibited lower tendency for oxidation.

  4. Immobilization of heavy metal ions (CuII, CdII, NiII, and PbII) by broiler litter-derived biochars in water and soil.

    Science.gov (United States)

    Uchimiya, Minori; Lima, Isabel M; Thomas Klasson, K; Chang, SeChin; Wartelle, Lynda H; Rodgers, James E

    2010-05-12

    Chars, a form of environmental black carbon resulting from incomplete burning of biomass, can immobilize organic contaminants by both surface adsorption and partitioning mechanisms. The predominance of each sorption mechanism depends upon the proportion of organic to carbonized fractions comprising the sorbent. Information is currently lacking in the effectiveness of char amendment for heavy metal immobilization in contaminated (e.g., urban and arms range) soils where several metal contaminants coexist. The present study employed sorbents of a common biomass origin (broiler litter manure) that underwent various degrees of carbonization (chars formed by pyrolysis at 350 and 700 degrees C and steam-activated analogues) for heavy metal (Cd(II), Cu(II), Ni(II), and Pb(II)) immobilization in water and soil. ATR-FTIR, (1)H NMR, and Boehm titration results suggested that higher pyrolysis temperature and activation lead to the disappearance (e.g., aliphatic -CH(2) and -CH(3)) and the formation (e.g., C-O) of certain surface functional groups, portions of which are leachable. Both in water and in soil, pH increase by the addition of basic char enhanced the immobilization of heavy metals. Heavy metal immobilization resulted in nonstoichiometric release of protons, that is, several orders of magnitude greater total metal concentration immobilized than protons released. The results suggest that with higher carbonized fractions and loading of chars, heavy metal immobilization by cation exchange becomes increasingly outweighed by other controlling factors such as the coordination by pi electrons (C=C) of carbon and precipitation.

  5. Development of a C3-symmetric benzohydroxamate tripod: Trimetallic complexation with Fe(III), Cr(III) and Al(III)

    Science.gov (United States)

    Baral, Minati; Gupta, Amit; Kanungo, B. K.

    2016-06-01

    The design, synthesis and physicochemical characterization of a C3-symmetry Benzene-1,3,5-tricarbonylhydroxamate tripod, noted here as BTHA, are described. The chelator was built from a benzene as an anchor, symmetrically extended by three hydroxamate as ligating moieties, each bearing O, O donor sites. A combination of absorption spectrophotometry, potentiometry and theoretical investigations are used to explore the complexation behavior of the ligand with some trivalent metal ions: Fe(III), Cr(III), and Al(III). Three protonation constants were calculated for the ligand in a pH range of 2-11 in a highly aqueous medium (9:1 H2O: DMSO). A high rigidity in the molecular structure restricts the formation of 1:1 (M/L) metal encapsulation but shows a high binding efficiency for a 3:1 metal ligand stoichiometry giving formation constant (in β unit) 28.73, 26.13 and 19.69 for [M3L]; Mdbnd Fe(III), Al(III) and Cr(III) respectively, and may be considered as an efficient Fe-carrier. The spectrophotometric study reveals of interesting electronic transitions occurred during the complexation. BTHA exhibits a peak at 238 nm in acidic pH and with the increase of pH, a new peak appeared at 270 nm. A substantial shifting in both of the peaks in presence of the metal ions implicates a s coordination between ligand and metal ions. Moreover, complexation of BTHA with iron shows three distinct colors, violet, reddish orange and yellow in different pH, enables the ligand to be considered for the use as colorimetric sensor.

  6. Speciative Determination of Dissolved Inorganic Fe(II, Fe(III and Total Fe in Natural Waters by Coupling Cloud Point Extraction with FAAS

    Directory of Open Access Journals (Sweden)

    Ramazan GÜRKAN

    2013-12-01

    Full Text Available A new cloud point extraction (CPE method for the preconcentration of trace iron speciation in natural waters prior to determination by flame atomic absorption spectrometry (FAAS was developed in the present study. In this method, Fe(II sensitively and selectively reacts with Calcon carboxylic acid (CCA in presence of cetylpyridinium chloride (CPC yielding a hydrophobic complex at pH 10.5, which is then entrapped in surfactant-rich phase. Total Fe was accurately and reliably determined after the reduction of Fe(III to Fe(II with sulfite. The amount of Fe(III in samples was determined from the difference between total Fe and Fe(II. CPC was used not only as an auxiliary ligand in CPE, but also as sensitivity enhancement agent in FAAS. The nonionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-114 was used as an extracting agent. The analytical variables affecting CPE efficiency were investigated in detail. The preconcentration/enhancement factors of 50 and 82 respectively, were obtained for the preconcentration of Fe(II with 50 mL solution. Under the optimized conditions, the detection limit of Fe(II in linear range of 0.2-60 μg L-1 was 0.06 μg L-1. The relative standard deviation was 2.7 % (20 μg L-1, N: 5, recoveries for Fe(II were in range of 99.0-102.0% for all water samples including certified reference materials (CRMs. In order to verify its accuracy, two CRMs were analyzed and the results obtained were statistically in good agreement with the certified values.

  7. Peptide-based FeS4 complexes: the zinc ribbon fold is unsurpassed to stabilize both the FeII and FeIII states.

    Science.gov (United States)

    Jacques, Aurélie; Latour, Jean-Marc; Sénèque, Olivier

    2014-03-14

    Whereas Zn(Cys)4 zinc fingers exist with different protein folds, only the zinc ribbon fold is found in rubredoxin Fe(Cys)4 sites. To assess the significance of this observation, we have investigated the binding and stability of Fe(2+) and Fe(3+) ions by a set of four peptides designed to model Zn(Cys)4 zinc fingers with various folds, i.e. zinc ribbon, treble clef and a loosened zinc ribbon fold. All peptides were shown by means of UV-Vis and CD spectroscopies to form stable 1 : 1 Fe(II)/peptide complexes with binding constants higher than 10(7) M(-1) at pH 7. Their oxidation into Fe(III) complexes and the stability of the latter were compared. The UV-Vis absorption and CD spectroscopic properties of the Fe(II) and Fe(III) complexes were analysed with respect to the structures of the zinc analogues in order to get insight into the local arrangement of the Fe(Cys)4 core around the metal ion. The chemical stability of these complexes was rationalized according to the shielding from the solvent provided by the various peptide folds to the FeS4 core. In addition, we showed that whereas UV-visible spectra inform only on the FeS4, the information derived from the corresponding CD spectra extend to the Cβ orientation and the peptide fold. The results presented here demonstrate that while the zinc ribbon fold is not strictly required to obtain a Fe(Cys)4 site, it affords a drastically superior protection of the site toward external redox agents. This finding brings new clues to engineer stable and redox-active Fe(Cys)4 sites in de novo proteins.

  8. Mn(II)/Mn(III) and Fe(III) binding capability of two Aspergillus fumigatus siderophores, desferricrocin and N', N″, N‴-triacetylfusarinine C.

    Science.gov (United States)

    Farkas, Etelka; Szabó, Orsolya; Parajdi-Losonczi, Péter L; Balla, György; Pócsi, István

    2014-10-01

    Manganese(II) and manganese(III) complexes of the exocyclic desferricrocin (H3DFCR) and endocyclic triacetylfusarinine C (H3TAF) in solution have been studied by using pH-potentiometry, UV-Vis spectrophotometry, relaxometry and cyclic voltammetry. A comparison between the present results and the corresponding ones for the open-chain analogues, desferrioxamine B (DFB) and desferricoprogen (DFC), shows (i) The dissociation processes of H3DFCR occur in the expected pH-range (pH7-10.5), but hydrogen bonding is assumed to be responsible for a quite low proton dissociation constant (pK=4.18) of H3TAF and also an unusually high one (10.59). (ii) Moderate stability complexes with 1:1 Mn(II) to ligand ratio are formed with all four siderophores. (iii) The coordination of the three hydroxamates of a siderophore takes place in stepwise processes, except the case of desferricrocin, with which, large-extent overlapping of the processes occurs. (iv) Out of the four tris-chelated [ML] type complexes, the complex of DFCR is the most compact, as it is indicated by the relaxivity values. (v) Following the stoichiometric oxidation of the Mn(II)-siderophore complexes at pH≥9, tris-chelated Mn(III) complexes are formed. To make a comparison between the stability of the Mn(III) and the corresponding Fe(III) complexes of DFCR and TAF, the determination of the stability of the Fe(III) complexes under our condition has also been performed, by using UV-Vis spectrophotometry. Comparable stability of the corresponding complexes was found. (vi) Correlation study of the stability constants resulted in estimation of the constant of the Mn(III) monohydroxo complex, for which there was no data in the literature under our conditions.

  9. Multi-component synthesis of 2-amino-6-(alkyllthio)pyridine-3,5-dicarbonitriles using Zn(II) and Cd(II) metal-organic frameworks (MOFs) under solvent-free conditions.

    Science.gov (United States)

    Thimmaiah, Muralidhara; Li, Peng; Regati, Sridhar; Chen, Banglin; Zhao, John Cong-Gui

    2012-09-05

    Multi-component synthesis 2-amino-3,5-dicarbonitrile-6-thio-pyridines has been developed by using the reaction of aldehydes, malononitrile, and thiophenols in the presence of a Zn (II) or a Cd(II) metal-organic framework (MOF) as the heterogeneous catalyst. This protocol tolerates different functional groups on the substrates and does not require the use of any organic solvent. Moreover, the Zn(II) and Cd (II) MOF catalysts can be recovered and reused for a number of runs without loss of activity.

  10. Complexation and coordination selectivities of the tetradentate ligand 7-[(2-hydroxy-5-sulfophenyl) azo]-8-hydroxyquinoline-5-sulfonic acid with Fe(II), Ni(II), Zn(II), Cd(II) and VO(IV)

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hu; Kai, Fumiaki; Hirohata, Masaaki; Nakamura, Masaaki; Matsuzaki, Susumu; Komori, Kenji; Tsunematsu, Yuriko [Kumamoto Univ. (Japan)

    1993-12-31

    The new title tetradentate ligand (SPAHQS), containing both phenylazo and 8-quinolinol fragments, was prepared. Proton-dissociation processes of the ligand and complexing equilibria with Fe(II), Ni(II), Zn(II), Cd(II), and VO(IV) were analyzed spectrophotometrically. Coordination modes of SPAHQS with these metal ions have been investigated by means of polarography and Raman spectroscopy in aqueous solution. It was established that the coordination selectivity of SPAHQS for such metal ions is mainly dependent on steric factors in the chelate ring formed, not on HSAB properties. 18 refs., 6 figs., 2 tabs.

  11. Coordination behavior of new bis Schiff base ligand derived from 2-furan carboxaldehyde and propane-1,3-diamine. Spectroscopic, thermal, anticancer and antibacterial activity studies.

    Science.gov (United States)

    Mohamed, Gehad G; Zayed, Ehab M; Hindy, Ahmed M M

    2015-06-15

    Novel bis Schiff base ligand, [N1,N3-bis(furan-2-ylmethylene)propane-1,3-diamine], was prepared by the condensation of furan-2-carboxaldehyde with propane-1,3-diamine. Its conformational changes on complexation with transition metal ions [Co(II), Ni(II), Cu(II), Mn(II), Cd(II), Zn(II) and Fe(III)] have been studied on the basis of elemental analysis, conductivity measurements, spectral (infrared, (1)H NMR, electronic), magnetic and thermogravimetric studies. The conductance data of the complexes revealed their electrolytic nature suggesting them as 1:2 (for bivalent metal ions) and 1:3 (for Fe(III) ion) electrolytes. The complexes were found to have octahedral geometry based on magnetic moment and solid reflectance measurements. Thermal analysis data revealed the decomposition of the complexes in successive steps with the removal of anions, coordinated water and bis Schiff base ligand. The thermodynamic parameters were calculated using Coats-Redfern equation. The Anticancer screening studies were performed on human colorectal cancer (HCT), hepatic cancer (HepG2) and breast cancer (MCF-7) cell lines. The antimicrobial activity of all the compounds was studied against Gram negative (Escherichia coli and Proteus vulgaris) and Gram positive (Bacillus vulgaris and Staphylococcus pyogones) bacteria. It was observed that the coordination of metal ion has a pronounced effect on the microbial activities of the bis Schiff base ligand. All the metal complexes have shown higher antimicrobial effect than the free bis Schiff base ligand.

  12. Ternary metal complexes of guaifenesin drug: Synthesis, spectroscopic characterization and in vitro anticancer activity of the metal complexes.

    Science.gov (United States)

    Mahmoud, W H; Mahmoud, N F; Mohamed, G G; El-Sonbati, A Z; El-Bindary, A A

    2015-01-01

    The coordination behavior of a series of transition metal ions named Cr(III), Fe(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with a mono negative tridentate guaifenesin ligand (GFS) (OOO donation sites) and 1,10-phenanthroline (Phen) is reported. The metal complexes are characterized based on elemental analyses, IR, (1)H NMR, solid reflectance, magnetic moment, molar conductance, UV-vis spectral studies, mass spectroscopy, ESR, XRD and thermal analysis (TG and DTG). The ternary metal complexes were found to have the formulae of [M(GFS)(Phen)Cl]Cl·nH2O (M=Cr(III) (n=1) and Fe(III) (n=0)), [M(GFS)(Phen)Cl]·nH2O (M=Mn(II) (n=0), Zn(II) (n=0) and Cu(II) (n=3)) and [M(GFS)(Phen)(H2O)]Cl·nH2O (M=Co(II) (n=0), Ni(II) (n=0) and Cd(II) (n=4)). All the chelates are found to have octahedral geometrical structures. The ligand and its ternary chelates are subjected to thermal analyses (TG and DTG). The GFS ligand, in comparison to its ternary metal complexes also was screened for their antibacterial activity on gram positive bacteria (Bacillus subtilis and Staphylococcus aureus), gram negative bacteria (Escherichia coli and Neisseria gonorrhoeae) and for in vitro antifungal activity against (Candida albicans). The activity data show that the metal complexes have antibacterial and antifungal activity more than the parent GFS ligand. The complexes were also screened for its in vitro anticancer activity against the Breast cell line (MFC7) and the results obtained show that they exhibit a considerable anticancer activity.

  13. Synthesis, characterization and spectroscopy studying of some metal complexes of a new Schiff base ligand; X-ray crystal structure, NMR and IR investigation of a new dodecahedron Cd(II) complex

    Science.gov (United States)

    Golbedaghi, Reza; Rezaeivala, Majid; Khalili, Maryam; Notash, Behrouz; Karimi, Javad

    2016-12-01

    Some new [Cd(H2L1)(NO3)]ClO4 (1), [Mn(H2L1)](ClO4)2 (2), [Ni(H2L1)](ClO4)2 (3) and [Cu(H2L1)](ClO4)2 (4) complexes were prepared by the reaction of a Schiff base ligand and M (II) metal ions in equimolar ratios (M = Cd, Mn, Ni and Cu). The ligand H2L1 was synthesized by reaction of 2-[2-(3-formyl phenoxy)propoxy]benzaldehyde and ethanol amine and characterized by IR, 1H,13C NMR spectroscopy and elemental analysis. The synthesized complexes were characterized with IR and elemental analysis in all cases and 1H, 13C NMR, and X-ray in the case of Cd(II) complex. The X-ray crystal structure of compound 1 showed that all nitrogen and oxygen atoms of Schiff base ligand (N2O4) and a molecule of nitrate with two donor oxygen atom have been coordinated to the metal ion and the Cd(II) ion is in an eight-coordinate environment that is best described as a distorted dodecahedron geometry.

  14. The heterobifunctional ligand 5-[4-(1,2,4-triazol-4-yl)phenyl]-1H-tetrazole and its role in the construction of a CdII metal-organic chain structure.

    Science.gov (United States)

    Lysenko, Andrey B

    2012-10-01

    5-[4-(1,2,4-Triazol-4-yl)phenyl]-1H-tetrazole, C(9)H(7)N(7), (I), an asymmetric heterobifunctional organic ligand containing triazole (tr) and tetrazole (tz) termini linked directly through a 1,4-phenylene spacer, crystallizes in the polar space group Pc. The heterocyclic functions, serving as single hydrogen-bond donor (tz) or acceptor (tr) units, afford hydrogen-bonded zigzag chains with no crystallographic centre of inversion. In the structure of catena-poly[[diaquacadmium(II)]bis{μ(2)-5-[4-(1,2,4-triazol-4-yl)phenyl]tetrazol-1-ido-κ(2)N(1):N(1')}], [Cd(C(9)H(6)N(7))(2)(H(2)O)(2)](n), (II), the Cd(II) dication resides on a centre of inversion in an octahedral {N(4)O(2)} environment. In the equatorial plane, the Cd(II) polyhedron is built up from four N atoms of two kinds, namely of trans-coordinating tr and tz fragments [Cd-N = 2.2926 (17) and 2.3603 (18) Å], and the coordinating aqua ligands occupy the two apical sites. The metal centres are separated at a distance of 11.1006 (7) Å by means of the double-bridging tetrazolate anion, L(-), forming a chain structure. The water ligands and tz fragments interact with one another, like a double hydrogen-bond donor-acceptor synthon, leading to a hydrogen-bonded three-dimensional array.

  15. Application of mesoporous SBA-15 silica functionalized with 4-amino-2-mercaptopyrimidine for the adsorption of Cu(II), Zn(II), Cd(II), Ni(II), and Pb(II) from water.

    Science.gov (United States)

    Jorgetto, Alexandre de Oliveira; Pereira, Silvana Pontes; Silva, Rafael Innocenti Vieira da; Saeki, Margarida Juri; Martines, Marco Antonio Utrera; Pedrosa, Valber de Albuquerque; Castro, Gustavo Rocha de

    2015-01-01

    This work reports the sol-gel synthesis of a SBA-15 silica, and its functionalization with 4-amino-2-mercaptopyrimidine to perform adsorption of metal species from aqueous media. The functionalization of the material was confirmed by FTIR and superficial area measurements. The final material was tested through batch experiments to uncover its adsorptive properties towards the adsorption of Cu(II), Cd(II), Zn(II), Pb(II) and Ni(II). Contact time and pH conditions were investigated, and the material presented slow adsorption kinetics, which was best described by the pseudo-second order model. In addition, at pH 5 - 6, the adsorption of the metal ions was favored. Under optimized conditions, the material had its maximum adsorption capacities determined for all metal species studied, and the obtained values were 13.0 µmol g(-1) for Zn(II), 12.3 µmol g(-1) for Cu(II), 3.45 µmol g(-1) for Ni(II), 2.45 µmol g(-1) for Pb(II) and 0.60 µmol g(-1) for Cd(II). The capacity differences between each metal ion were discussed in terms of their ionic radii and Person's soft/hard acids/bases concept.

  16. Synthesis of amino functionalized magnetic graphenes composite material and its application to remove Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II) from contaminated water.

    Science.gov (United States)

    Guo, Xiaoyao; Du, Bin; Wei, Qin; Yang, Jian; Hu, Lihua; Yan, Liangguo; Xu, Weiying

    2014-08-15

    In the present study, a kind of graphenes magnetic material (Fe3O4-GS) was prepared by compositing graphene sheet with ferroferric oxide, and shown to be effective for removing Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II) ions from aqueous solution. The synthesized sorbent was characterized by SEM, TEM, FTIR, XRD, XPS and BET, respectively. The pHZPC value of the sorbent was estimated to be 3.5 by alkaline-titration methods. Fe3O4-GS can be simply recovered from water with magnetic separation at low magnetic field within one minute. The sorption capacities of the metals were 17.29, 27.95, 23.03, 27.83 and 22.07 mg g(-1) for Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II), respectively. Kinetic data showed good correlation with pseudo-second-order equation and the Freundlich model was found to fit for the isotherm data of all the heavy metal ions. It was found that the metals sorption was accomplished mainly via chelation or ion exchange. The results of thermodynamic studies illustrate that the adsorption process was endothermic and spontaneous in nature.

  17. Preconcentration of Pb(II), Cr(III), Cu(II), Ni(II) and Cd(II) ions in environmental samples by membrane filtration prior to their flame atomic absorption spectrometric determinations

    Energy Technology Data Exchange (ETDEWEB)

    Divrikli, Umit [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey)]. E-mail: udivrikli@pamukkale.edu.tr; Kartal, Aslihan Arslan [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Arts and Science, Department of Chemistry, 38039 Kayseri (Turkey); Elci, Latif [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, 20020 Denizli (Turkey)

    2007-07-16

    A method for separation-preconcentration of Pb(II), Cr(III), Cu(II), Ni(II) and Cd(II) ions by membrane filtration has been described. The method based on the collection of analyte metal ions on a cellulose nitrate membrane filter and determination of analytes by flame atomic absorption spectrometry (FAAS). The method was optimized for several parameters including of pH, matrix effects and sample volume. The recoveries of analytes were generally in the range of 93-100%. The detection limits by 3 sigma for analyte ions were 0.02 {mu}g L{sup -1} for Pb(II), 0.3 {mu}g L{sup -1} for Cr(III), 3.1 {mu}g L{sup -1} for Cu(II), 7.8 {mu}g L{sup -1} for Ni(II) and 0.9 {mu}g L{sup -1} for Cd(II). The proposed method was applied to the determination of lead, chromium, copper, nickel and cadmium in tap waters and RM 8704 Buffalo River Sediment standard reference material with satisfactory results. The relative standard deviations of the determinations were below 10%.

  18. The meloxicam complexes of Co(II) and Zn(II): Synthesis, crystal structures, photocleavage and in vitro DNA-binding

    Science.gov (United States)

    Sanatkar, Tahereh Hosseinzadeh; Hadadzadeh, Hassan; Simpson, Jim; Jannesari, Zahra

    2013-10-01

    Two neutral mononuclear complexes of Co(II) and Zn(II) with the non-steroidal anti-inflammatory drug meloxicam (H2mel, 4-hydroxy-2-methyl-N-(5-methyl-2-thiazolyl)-2H-1,2-benzothiazine-3-carboxammide-1,1-dioxide), [Co(Hmel)2(EtOH)2] (1), and [Zn(Hmel)2(EtOH)2] (2), were synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopy and their solid-state structures were studied by single-crystal diffraction. The complexes have a distorted octahedral geometry around the metal atom. The experimental data indicate that the meloxicam acts as a deprotonated bidentate ligand (through the amide oxygen and the nitrogen atom of the thiazolyl ring) in the complexes, and a strong intramolecular hydrogen bond between the amide N-H function and the enolate O atom stabilizes the ZZZ conformation of meloxicam ligands. Absorption, fluorescence spectroscopy and cyclic voltammetry have been used to investigate the binding of the complexes with fish sperm DNA (FS-DNA). Additionally, the photocleavage studies have been also used to investigate the binding of the complexes with plasmid DNA. The interaction of the complexes with DNA was monitored by a blue shift and hyperchromism in the UV-Vis spectra attributed to an electrostatic binding mode. A competitive study with ethidium bromide (EB) has shown that the complexes can displace the DNA-bound EB indicating that they bind to DNA in strong competition with EB. The experimental results show that the complexes can cleave pUC57 plasmid DNA.

  19. Interaction of a dinuclear fluorescent Cd(II) complex of calix[4]arene conjugate with phosphates and its applicability in cell imaging.

    Science.gov (United States)

    Sreenivasu Mummidivarapu, V V; Hinge, Vijaya Kumar; Rao, Chebrolu Pulla

    2015-01-21

    A triazole-linked hydroxyethylimino conjugate of calix[4]arene () and its cadmium complex have been synthesized and characterized, and their structures have been established. In the complex, both the Cd(2+) centers are bound by an N2O4 core, and one of it is a distorted octahedral, whereas the other is a trigonal anti-prism. The fluorescence intensity of the di-nuclear Cd(ii) complex is quenched only in the presence of phosphates and not with other anions studied owing to their binding affinities and the nature of the interaction of the phosphates with Cd(2+). These are evident even from their absorption spectra. Different phosphates exhibit changes in both their fluorescence as well as absorption spectra to varying extents, suggesting their differential interactions. Among the six phosphates, H2PO4(-) has higher fluorescence quenching even at low equivalents of this ion, whereas P2O7(4-) shows only 50% quenching even at 10 equivalents. The fluorescence quenching is considerable even at 20 ppb (0.2 μM) of H2PO4(-), whereas all other phosphates require a concentration of 50-580 ppb to exhibit the same effect on fluorescence spectra. Thus, the interaction of H2PO4(-) is more effective by ∼30 fold as compared to that of P2O7(4-). Fluorescence quenching by phosphate is due to the release of from its original cadmium complex via the formation of a ternary species followed by the capture of Cd(2+) by the phosphate, as delineated based on the combination of spectral techniques, such as absorption, emission, (1)H NMR and ESI MS. The relative interactive abilities of the six phosphates differ from each other. The removal of Cd(2+) is demonstrated to be reversible by the repeated addition of the phosphate followed by Cd(2+). The characteristics of the ternary species formed in each of these six phosphates have been computationally modeled using molecular mechanics. The computational study revealed that the coordination between cadmium and -CH2-CH2-OH breaks and new

  20. Synthesis, Spectral Characterization, Molecular Modeling, and Antimicrobial Studies of Cu(II, Ni(II, Co(II, Mn(II, and Zn(II Complexes of ONO Schiff Base

    Directory of Open Access Journals (Sweden)

    Padmaja Mendu

    2012-01-01

    Full Text Available A series of Cu(II, Ni(II, Co(II, Mn(II, and Zn(II complexes have been synthesized from the schiff base ligand L. The schiff base ligand [(4-oxo-4H-chromen-3-yl methylene] benzohydrazide (L has been synthesized by the reaction between chromone-3-carbaldehyde and benzoyl hydrazine. The nature of bonding and geometry of the transition metal complexes as well as schiff base ligand L have been deduced from elemental analysis, FT-IR, UV-Vis, 1HNMR, ESR spectral studies, mass, thermal (TGA and DTA analysis, magnetic susceptibility, and molar conductance measurements. Cu(II, Ni(II, Co(II, and Mn(II metal ions are forming 1:2 (M:L complexes, Zn(II is forming 1:1 (M:L complex. Based on elemental, conductance and spectral studies, six-coordinated geometry was assigned for Cu(II, Ni(II, Co(II, Mn(II, and Zn(II complexes. The complexes are 1:2 electrolytes in DMSO except zinc complex, which is neutral in DMSO. The ligand L acts as tridentate and coordinates through nitrogen atom of azomethine group, oxygen atom of keto group of γ-pyrone ring and oxygen atom of hydrazoic group of benzoyl hydrazine. The 3D molecular modeling and energies of all the compounds are furnished. The biological activity of the ligand and its complexes have been studied on the four bacteria E. coli, Edwardella, Pseudomonas, and B. subtilis and two fungi pencillium and tricoderma by well disc and fusion method and found that the metal chelates are more active than the free schiff base ligand.

  1. Synthesis, antimicrobial activity, structural and spectral characterization and DFT calculations of Co(II), Ni(II), Cu(II) and Pd(II) complexes of 4-amino-5-pyrimidinecarbonitrile.

    Science.gov (United States)

    Mohamed, Tarek A; Shaaban, Ibrahim A; Farag, Rabei S; Zoghaib, Wajdi M; Afifi, Mahmoud S

    2015-01-25

    Co(II), Ni(II), Cu(II) and Pd(II) complexes of 4-amino-5-pyrimidinecarbonitrile (APC) have been synthesized and characterized using elemental analysis, magnetic susceptibility, mass spectrometry, infrared (4000-200 cm(-1)), UV-Visible (200-1100 nm), (1)H NMR and ESR spectroscopy as well as TGA analysis. The molar conductance measurements in DMSO imply non-electrolytic complexes, formulated as [M(APC)2Cl2] where M=Co(II), Ni(II), Cu(II) and Pd(II). The infrared spectra of Co(II), Ni(II) and Cu(II) complexes indicate a bidentate type of bonding for APC through the exocyclic amino and adjacent pyrimidine nitrogen as donors whereas APC coordinated to Pd(II) ion as a monodentated ligand via a pyrimidine nitrogen donor. The magnetic measurements and the electronic absorption spectra support distorted octahedral geometries for Co(II), Ni(II) and Cu(II) complexes however a square planar complex was favored for the Pd(II) complex (C2h skeleton symmetry). In addition, we carried out B3LYP and ω-B97XD geometry optimization at 6-31G(d) basis set except for Pd(II) where we implemented LanL2DZ/6-31G(d) combined basis set. The computational results favor all trans geometrical isomers where amino N, pyrimidine N and Cl are trans to each other (structure 1). Finally, APC and its divalent metal ion complexes were screened for their antibacterial activity, and the synthesized complexes were found to be more potent antimicrobial agents than APC against one or more microbial species.

  2. A new combined process for efficient removal of Cu(II) organic complexes from wastewater: Fe(III) displacement/UV degradation/alkaline precipitation.

    Science.gov (United States)

    Xu, Zhe; Gao, Guandao; Pan, Bingcai; Zhang, Weiming; Lv, Lu

    2015-12-15

    Efficient removal of heavy metals complexed with organic ligands from water is still an important but challenging task now. Herein, a novel combined process, i.e., Fe(III)-displacement/UV degradation/alkaline precipitation (abbreviated as Fe(III)/UV/OH) was developed to remove copper-organic complexes from synthetic solution and real electroplating effluent, and other processes including alkaline precipitation, Fe(III)/OH, UV/OH were employed for comparison. By using the Fe(III)/UV/OH process, some typical Cu(II) complexes, such as Cu(II)-ethylenediaminetetraacetic acid (EDTA), Cu(II)-nitrilotriacetic acid (NTA), Cu(II)-citrate, Cu(II)-tartrate, and Cu(II)-sorbate, each at 19.2 mg Cu/L initially, were efficiently removed from synthetic solution with the residual Cu below 1 mg/L. Simultaneously, 30-48% of total organic carbon was eliminated with exception of Cu(II)-sorbate. Comparatively, the efficiency of other processes was much lower than the Fe(III)/UV/OH process. With Cu(II)-citrate as the model complex, the optimal conditions for the combined process were obtained as: initial pH for Fe(III) displacement, 1.8-5.4; molar ratio of [Fe]/[Cu], 4:1; UV irradiation, 10 min; precipitation pH, 6.6-13. The mechanism responsible for the process involved the liberation of Cu(II) ions from organic complexes as a result of Fe(III) displacement, decarboxylation of Fe(III)-ligand complexes subjected to UV irradiation, and final coprecipitation of Cu(II) and Fe(II)/Fe(III) ions. Up to 338.1 mg/L of Cu(II) in the electroplating effluent could be efficiently removed by the process with the residual Cu(II) below 1 mg/L and the removal efficiency of ∼99.8%, whereas direct precipitation by using NaOH could only result in total Cu(II) removal of ∼8.6%. In addition, sunlight could take the place of UV to achieve similar removal efficiency with longer irradiation time (90 min).

  3. Hydrothermal syntheses and single crystal structural characterization of M(H2O)6(OPTA)2 [M = Co(II), Ni(II), Zn(II); OPTA = 1-oxopyridinium-2-thioacetato

    Indian Academy of Sciences (India)

    S Kumaresan; P Ramadevi; R D Walsh; A McAneny; C H Lake

    2006-05-01

    A new class of compounds of the family M(H2O)6(OPTA)2 (where M = Co(II), Ni(II), and Zn(II); OPTA = 1-oxopyridinium-2-thioacetato) was prepared from the appropriate metal acetates, 1-oxopyridinium-2-thioacetic acid (OPTAH), and potassium hydroxide in hydrothermal media and structurally characterized. The structure is constructed from M(H2O)$_{6}^{2+}$ and two anions of OPTAH (C7H6NO3S) linked through hydrogen bonding into an extended network.

  4. Fe(III) in a low-spin state in caesium bis[3-ethoxysalicylaldehyde 4-methylthiosemicarbazonato(2-)-κ3O2,N1,S]ferrate(III) methanol monosolvate.

    Science.gov (United States)

    Powell, Robyn E; Schwalbe, Carl H; Tizzard, Graham J; Koningsbruggen, Petra J van

    2014-06-01

    The synthesis and crystal structure (at 100 K) of the title compound, Cs[Fe(C11H13N3O2S2)2]·CH3OH, is reported. The asymmetric unit consists of an octahedral [Fe(III)(L)2](-) fragment, where L(2-) is 3-ethoxysalicylaldehyde 4-methylthiosemicarbazonate(2-) {systematic name: [2-(3-ethoxy-2-oxidobenzylidene)hydrazin-1-ylidene](methylamino)methanethiolate}, a caesium cation and a methanol solvent molecule. Each L(2-) ligand binds through the thiolate S, the imine N and the phenolate O atoms as donors, resulting in an Fe(III)S2N2O2 chromophore. The O,N,S-coordinating ligands are orientated in two perpendicular planes, with the O and S atoms in cis positions and the N atoms in trans positions. The Fe(III) cation is in the low-spin state at 100 K.

  5. mer-[Fe(pcq)(CN)3]-: a novel cyanide-containing building block and its application to assembling cyanide-bridged trinuclear FeIII2MnII complexes [pcq- = 8-(pyridine-2-carboxamido)quinoline anion].

    Science.gov (United States)

    Ni, Zhong-Hai; Kou, Hui-Zhong; Zhang, Li-Fang; Ni, Wei-Wei; Jiang, Yun-Bo; Cui, Ai-Li; Ribas, Joan; Sato, Osamu

    2005-12-26

    A new cyanide-containing building block K[Fe(pcq)(CN)(3)] [1; pcq(-) = 8-(pyridine-2-carboxamido)quinoline anion] containing a low-spin Fe(III) center with three cyanide groups in a meridional arrangement has been successfully designed and synthesized. Three cyanide-bridged trinuclear Fe(III)(2)Mn(II) complexes, [Fe(pcq)(CN)(3)](2)[Mn(CH(3)OH)(2)(H(2)O)(2)].2H(2)O (2), [Fe(pcq)(CN)(3)](2)[Mn(bipy)(2)].CH(3)OH.2H(2)O (3), and [Fe(pcq)(CN)(3)](2)[Mn(phen)(2)].CH(3)OH.2H(2)O (4), have been synthesized and structurally characterized. The magnetic susceptibilities of the three heterometallic complexes have been investigated.

  6. Synthesis, characterization, fluorescence and biological studies of Mn(II, Fe(III and Zn(II complexes of Schiff bases derived from Isatin and 3-substituted-4-amino-5-mercapto-1,2,4-triazoles

    Directory of Open Access Journals (Sweden)

    Sangamesh A. Patil

    2014-12-01

    Full Text Available A series of Mn(II, Fe(III and Zn(II complexes have been synthesized with Schiff bases derived from isatin and 3-substituted-4-amino-5-mercapto-1,2,4-triazole. The elemental, spectroscopic (Infrared, nuclear magnetic resonance, ultraviolet-visible, fast atom bombardment-mass, fluorescence and electrochemistry and magnetic studies suggested that the metal complexes possess octahedral geometry. The Schiff bases and their metal complexes exhibit fluorescent properties. The antimicrobial studies of Schiff bases and their metal complexes against various bacterial (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis and fungal (Aspergillus niger, and Penicillium chrysogenum species by the minimum inhibitory concentration method revealed that the metal complexes possess more healing antibacterial activities than the Schiff bases. DNA cleavage property of Mn(II, Fe(III and Zn(II complexes revealed the important role of metal ion in the biological system.

  7. Cr(III), Fe(III) and Co(III) complexes of tetradentate (ONNO) Schiff base ligands: Synthesis, characterization, properties and biological activity

    Science.gov (United States)

    Keskioğlu, Eren; Gündüzalp, Ayla Balaban; Çete, Servet; Hamurcu, Fatma; Erk, Birgül

    2008-08-01

    A series of metal complexes were synthesized from equimolar amounts of Schiff bases: 1,4-bis[3-(2-hydroxy-1-naphthaldimine)propyl]piperazine (bappnaf) and 1,8-bis[3-(2-hydroxy-1-naphthaldimine)- p-menthane (damnaf) with metal chlorides. All of synthesized compounds were characterized by elemental analyses, spectral (UV-vis, IR, 1H- 13C NMR, LC-MS) and thermal (TGA-DTA) methods, magnetic and conductance measurements. Schiff base complexes supposed in tetragonal geometry have the general formula [M(bappnaf or damnaf)]Cl· nH 2O, where M = Cr(III), Co(III) and n = 2, 3. But also Fe(III) complexes have octahedral geometry by the coordination of two water molecules and the formula is [Fe(bappnaf or damnaf)(H 2O) 2]Cl. The changes in the selected vibration bands in FT-IR indicate that Schiff bases behave as (ONNO) tetradentate ligands and coordinate to metal ions from two phenolic oxygen atoms and two azomethine nitrogen atoms. Conductance measurements suggest 1:1 electrolytic nature of the metal complexes. The synthesized compounds except bappnaf ligand have the antimicrobial activity against the bacteria: Escherichia coli (ATCC 11230), Yersinia enterocolitica (ATCC 1501), Bacillus magaterium (RSKK 5117), Bacillus subtilis (RSKK 244), Bacillus cereus (RSKK 863) and the fungi: Candida albicans (ATCC 10239). These results have been considerably interest in piperazine derivatives due to their significant applications in antimicrobial studies.

  8. Coordination polymers of Fe(iii) and Al(iii) ions with TCA ligand: distinctive fluorescence, CO2 uptake, redox-activity and oxygen evolution reaction.

    Science.gov (United States)

    Dhara, Barun; Sappati, Subrahmanyam; Singh, Santosh K; Kurungot, Sreekumar; Ghosh, Prasenjit; Ballav, Nirmalya

    2016-04-28

    Fe and Al belong to different groups in the periodic table, one from the p-block and the other from the d-block. In spite of their different groups, they have the similarity of exhibiting a stable 3+ oxidation state. Here we have prepared Fe(iii) and Al(iii) based coordination polymers in the form of metal-organic gels with the 4,4',4''-tricarboxyltriphenylamine (TCA) ligand, namely Fe-TCA and Al-TCA, and evaluated some important physicochemical properties. Specifically, the electrical conductivity, redox-activity, porosity, and electrocatalytic activity (oxygen evolution reaction) of the Fe-TCA system were noted to be remarkably higher than those of the Al-TCA system. As for the photophysical properties, almost complete quenching of the fluorescence originating from TCA was observed in case of the Fe-TCA system, whereas for the Al-TCA system a significant retention of fluorescence with red-shifted emission was observed. Quantum mechanical calculations based on density functional theory (DFT) were performed to unravel the origin of such discriminative behaviour of these coordination polymer systems.

  9. Use of coal mining waste for the removal of acidity and metal ions Al(III), Fe(III) and Mn(II) in acid mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Geremias, R.; Laus, R.; Macan, J.M.; Pedrosa, R.C.; Laranjeira, M.C.M.; Silvan, J.; Favere, F.V. [Universidade Federal de Santa Catarina, Florianopolis (Brazil)

    2008-08-15

    The coal industry may generate acid mine drainage (AMD) and mining wastes, which may adversely affect the quality of the environment. In this study we propose the use of this waste in the removal of acidity and metal ions, as well as in the reduction of the toxicity of AMD. A physico-chemical analysis of the waste shows the presence of mainly SiO{sub 2}, Al{sub 2}O{sub 3} and Fe{sub 2}O{sub 3} and a superficial area of 4.316 m{sup 2} g{sup -1}. The treatment of AMD with the waste resulted in an increase in pH from 2.6 to 7.8 and removed 100% of the Al(III), 100% of the Fe(III) and 89% of the Mn (II). We also observed that the high toxicity of the AMD towards Daphnia magna (LC50 = 3.68%) and Artemia sp. (LC50 = 4.97%) was completely eliminated after treatment with the waste. The data obtained allow us to propose that the waste can be used in the treatment of AMD, providing an economic use for the waste.

  10. Texturing a pyramid-like structure on a silicon surface via the synergetic effect of copper and Fe(III) in hydrofluoric acid solution

    Science.gov (United States)

    Cao, Ming; Li, Shaoyuan; Deng, Jianxin; Li, Yuping; Ma, Wenhui; Zhou, Yang

    2016-05-01

    An innovative approach is proposed to texture a pyramid structure on a silicon surface via Cu-catalyzed chemical etching in the HF/FeCl3 system. The surface and cross-section morphologies of the formed pyramid structure were examined by scanning electron microscopy and atomic force microscopy. The results revealed that numerous silicon pyramid-like structures with hemlines of 0.1 ∼ 3 μm and height of 0.1 ∼ 2 μm are close together, and the top angle of the pyramid structure is 90°. Additionally, the systematic study of the effects of the etching time and the concentration of FeCl3 on the pyramid-like structures by the atom configuration model of silicon crystal faces demonstrated that the etching proceeds preferentially along the directions of silicon. A formation mechanism of the pyramid-like structure is proposed. The results imply that the synergetic effect of Cu nanoparticles and Fe(III) could conveniently generate a pyramid-like architecture on the surface of silicon in hydrofluoric acid solution.

  11. Fe(III) hydroxide nucleation and growth on quartz in the presence of Cu(II), Pb(II), and Cr(III): metal hydrolysis and adsorption.

    Science.gov (United States)

    Dai, Chong; Hu, Yandi

    2015-01-06

    Fe(III) hydroxide nanoparticles are an essential carrier for aqueous heavy metals. Particularly, iron hydroxide precipitation on mineral surfaces can immobilize aqueous heavy metals. Here, we used grazing-incidence small-angle X-ray scattering (GISAXS) to quantify nucleation and growth of iron hydroxide on quartz in 0.1 mM Fe(NO3)3 solution in the presence of Na(+), Cu(2+), Pb(2+), or Cr(3+) at pH = 3.7 ± 0.1. In 30 min, the average radii of gyration (R(g)) of particles on quartz grew from around 2 to 6 nm in the presence of Na(+) and Cu(2+). Interestingly, the particle sizes remained 3.3 ± 0.3 nm in the presence of Pb(2+), and few particles formed in the presence of Cr(3+). Quartz crystal microbalance dissipation (QCM-D) measurements showed that only Cr(3+) adsorbed onto quartz, while Cu(2+) and Pb(2+) did not. Cr(3+) adsorption changed the surface charge of quartz from negative to positive, thus inhibiting the precipitation of positively charged iron hydroxide on quartz. Masses and compositions of the precipitates were also quantified. This study provided new insights on interactions among quartz, iron hydroxide, and metal ions. Such information is helpful not only for environmental remediation but also for the doping design of iron oxide catalysts.

  12. Cr(III), Fe(III) and Co(III) complexes of tetradentate (ONNO) Schiff base ligands: synthesis, characterization, properties and biological activity.

    Science.gov (United States)

    Keskioğlu, Eren; Gündüzalp, Ayla Balaban; Cete, Servet; Hamurcu, Fatma; Erk, Birgül

    2008-08-01

    A series of metal complexes were synthesized from equimolar amounts of Schiff bases: 1,4-bis[3-(2-hydroxy-1-naphthaldimine)propyl]piperazine (bappnaf) and 1,8-bis[3-(2-hydroxy-1-naphthaldimine)-p-menthane (damnaf) with metal chlorides. All of synthesized compounds were characterized by elemental analyses, spectral (UV-vis, IR, (1)H-(13)C NMR, LC-MS) and thermal (TGA-DTA) methods, magnetic and conductance measurements. Schiff base complexes supposed in tetragonal geometry have the general formula [M(bappnaf or damnaf)]Cl.nH(2)O, where M=Cr(III), Co(III) and n=2, 3. But also Fe(III) complexes have octahedral geometry by the coordination of two water molecules and the formula is [Fe(bappnaf or damnaf)(H(2)O)(2)]Cl. The changes in the selected vibration bands in FT-IR indicate that Schiff bases behave as (ONNO) tetradentate ligands and coordinate to metal ions from two phenolic oxygen atoms and two azomethine nitrogen atoms. Conductance measurements suggest 1:1 electrolytic nature of the metal complexes. The synthesized compounds except bappnaf ligand have the antimicrobial activity against the bacteria: Escherichia coli (ATCC 11230), Yersinia enterocolitica (ATCC 1501), Bacillus magaterium (RSKK 5117), Bacillus subtilis (RSKK 244), Bacillus cereus (RSKK 863) and the fungi: Candida albicans (ATCC 10239). These results have been considerably interest in piperazine derivatives due to their significant applications in antimicrobial studies.

  13. Experimental and molecular modeling studies of the interaction of the polypyridyl Fe(II) and Fe(III) complexes with DNA and BSA.

    Science.gov (United States)

    Behnamfar, Mohammad Taghi; Hadadzadeh, Hassan; Simpson, Jim; Darabi, Farivash; Shahpiri, Azar; Khayamian, Taghi; Ebrahimi, Malihe; Amiri Rudbari, Hadi; Salimi, Mona

    2015-01-01

    Two mononuclear iron complexes, [Fe(tppz)₂](PF₆)₂·H₂O (1) and Fe(tppz)Cl₃·2CHCl₃ (2) where tppz is (2,3,5,6-tetra(2-pyridyl)pyrazine), have been synthesized and characterized by elemental analysis, spectroscopic methods (UV-Vis and IR) and single crystal X-ray structure analysis. The interaction of (1) as the nitrate salt ([Fe(tppz)₂](NO₃)₂) with calf-thymus DNA (CT-DNA) has been monitored by UV-Vis spectroscopy, competitive fluorescence titration, circular dichroism (CD), voltammetric techniques, viscosity measurement, and gel electrophoresis. Gel electrophoresis of DNA with [Fe(tppz)₂](NO₃)₂ demonstrated that the complex also has the ability to cleave supercoiled plasmid DNA. The results have indicated that the complex binds to CT-DNA by three binding modes, viz., electrostatic, groove and partial insertion of the pyridyl rings between the base stacks of double-stranded DNA. Molecular docking of [Fe(tppz)₂](NO₃)₂ with the DNA sequence d(ACCGACGTCGGT)₂ suggests the complex fits into the major groove. The water-insoluble complex (2) can catalyze the cleavage of BSA at 40 °C. There are no reports of the catalytic effect of polypyridyl metal complexes on the BSA cleavage. Molecular docking of (2) with BSA suggests that, when the chloro ligands in the axial positions are replaced by water molecules, the BSA can interact with the Fe(III) complex more easily.

  14. Cu(II), Fe(III) and Mn(II) combinations as environmental stress factors have distinguishing effects on Enterococcus hirae.

    Science.gov (United States)

    Vardanyan, Zaruhi; Trchounian, Armen

    2015-02-01

    Pollution by various heavy metals as environmental stress factors might affect bacteria. It was established that iron (Fe(III)), manganese (Mn(II)) and copper (Cu(II)) ion combinations caused effects on Enterococcus hirae that differed from the sum of the effects when the metals were added separately. It was shown that the Cu2+-Fe3+ combination decreased the growth and ATPase activity of membrane vesicles of wild-type E. hirae ATCC9790 and atpD mutant (with defective FoF1-ATPase) MS116. Addition of Mn2+-Fe3+ combinations within the same concentration range had no effects on growth compared to control (without heavy metals). ATPase activity was increased in the presence of Mn2+-Fe3+, while together with 0.2 mmol/L N,N'-dicyclohexylcarbodiimide (DCCD), ATPase activity was decreased compared to control (when only 0.2 mmol/L DCCD was present). These results indicate that heavy metals ion combinations probably affect the FOF1-ATPase, leading to conformational changes. Moreover the action may be direct or be mediated by environment redox potential. The effects observed when Fe3+ was added separately disappeared in both cases, which might be a result of competing processes between Fe3+ and other heavy metals. These findings are novel and improve the understanding of heavy metals ions effects on bacteria, and could be applied for regulation of stress response patterns in the environment.

  15. Adsorption of some transition metal ions (Cu(II), Fe(III), Cr(III) and Au(III)) onto lignite-based activated carbons modified by oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Paunka St. Vassileva; Albena K. Detcheva [Bulgarian Academy of Sciences, Sofia (Bulgaria). Institute of General and Inorganic Chemistry

    2010-03-15

    The main purpose of the present work was to study the adsorption of some transition metal ions from aqueous solution via a novel porous material obtained from Bulgarian lignite (Chukurovo deposit) and its oxidized modifications. The adsorption of Cu(II), Fe(III), Cr(III) and Au(III) ions was investigated using batch methods to study solutions with different concentrations and acidities. It was found that the adsorption process was affected significantly by the pH value of the aqueous solution. Treatment of the equilibrium data using the linear Langmuir, Freundlich and Dubinin-Radushkevich models allowed the maximum adsorption capacities to be calculated. The uptake of Au(III) ions was almost 100% for the three adsorbents investigated, being greater than 300 mg/l and independent of the pH over the pH range studied. The initial activated carbon proved to be the most suitable for the selective adsorption of Au(III) ions from aqueous solutions in the presence of other transition metal ions, while its oxidized modification Ch-P exhibited an enhanced adsorption efficiency towards transition metals.

  16. Adsorption of Some Transition Metal Ions (Cu(II), Fe(III), Cr(III) and Au(III)) onto lignite-based activated carbons modified by oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Vassileva, P.S.; Detcheva, A.K. [Bulgarian Academy of Science, Sofia (Bulgaria)

    2010-07-01

    The main purpose of the present work was to study the adsorption of some transition metal ions from aqueous solution via a novel porous material obtained from Bulgarian lignite (Chukurovo deposit) and its oxidized modifications. The adsorption of Cu(II), Fe(III), Cr(III) and Au(III) ions was investigated using batch methods to study solutions with different concentrations and acidities. It was found that the adsorption process was affected significantly by the pH value of the aqueous solution. Treatment of the equilibrium data using the linear Langmuir, Freundlich and Dubinin-Radushkevich models allowed the maximum adsorption capacities to be calculated. The uptake of Au(III) ions was almost 100% for the three adsorbents investigated, being greater than 300 mg/l and independent of the pH over the pH range studied. The initial activated carbon proved to be the most suitable for the selective adsorption of Au(III) ions from aqueous solutions in the presence of other transition metal ions, while its oxidized modification Ch-P exhibited an enhanced adsorption efficiency towards transition metals.

  17. Synthesis, structure, thermostability and luminescence properties of Zn(II) and Cd(II) coordination polymers based on dimethysuccinate and flexible 1,4-bis(imidazol-1-ylmethyl)benzene ligands.

    Science.gov (United States)

    Liu, Yang; Feng, Yong Lan; Fu, Wei Wei

    2016-09-01

    The design and synthesis of functional coordination polymers is motivated not only by their structural beauty but also by their potential applications. Zn(II) and Cd(II) coordination polymers are promising candidates for producing photoactive materials because these d(10) metal ions not only possess a variety of coordination numbers and geometries, but also exhibit luminescence properties when bound to functional ligands. It is difficult to predict the final structure of such polymers because the assembly process is influenced by many subtle factors. Bis(imidazol-1-yl)-substituted alkane/benzene molecules are good bridging ligands because their flexibility allows them to bend and rotate when they coordinate to metal centres. Two new Zn(II) and Cd(II) coordination polymers based on mixed ligands, namely, poly[[μ2-1,4-bis(imidazol-1-ylmethyl)benzene-κ(2)N(3):N(3')]bis(μ3-2,2-dimethylbutanoato-κ(3)O(1):O(4):O(4'))dizinc(II)], [Zn2(C6H8O4)2(C14H14N4)]n, and poly[[μ2-1,4-bis(imidazol-1-ylmethyl)benzene-κ(2)N(3):N(3')]bis(μ3-2,2-dimethylbutanoato-κ(5)O(1),O(1'):O(4),O(4'):O(4))dicadmium(II)], [Cd2(C6H8O4)2(C14H14N4)]n, have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis. Both complexes crystallize in the monoclinic space group C2/c with similar unit-cell parameters and feature two-dimensional structures formed by the interconnection of S-shaped Zn(Cd)-2,2-dimethylsuccinate chains with 1,4-bis(imidazol-1-ylmethyl)benzene bridges. However, the Cd(II) and Zn(II) centres have different coordination numbers and the 2,2-dimethylsuccinate ligands display different coordination modes. Both complexes exhibit a blue photoluminescence in the solid state at room temperature.

  18. Synthesis, spectral characterization thermal stability, antimicrobial studies and biodegradation of starch–thiourea based biodegradable polymeric ligand and its coordination complexes with [Mn(II, Co(II, Ni(II, Cu(II, and Zn(II] metals

    Directory of Open Access Journals (Sweden)

    Nahid Nishat

    2016-09-01

    Full Text Available A biodegradable polymer was synthesized by the modification reaction of polymeric starch with thiourea which is further modified by transition metals, Mn(II, Co(II, Ni(II, Cu(II and Zn(II. All the polymeric compounds were characterized by (FT-IR spectroscopy, 1H NMR spectroscopy, 13C NMR spectroscopy, UV–visible spectra, magnetic moment measurements, thermogravimetric analysis (TGA and antibacterial activities. Polymer complexes of Mn(II, Co(II and Ni(II show octahedral geometry, while polymer complexes of Cu(II and Zn(II show square planar and tetrahedral geometry, respectively. The TGA revealed that all the polymer metal complexes are more thermally stable than their parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM-D-5338-93 standards of biodegradable polymers by CO2 evolution method which says that coordination decreases biodegradability. The antibacterial activity was screened with the agar well diffusion method against some selected microorganisms. Among all the complexes, the antibacterial activity of the Cu(II polymer–metal complex showed the highest zone of inhibition because of its higher stability constant.

  19. Synthesis, characterization and DNA binding/cleavage, protein binding and cytotoxicity studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes of aminonaphthoquinone.

    Science.gov (United States)

    Kosiha, A; Parthiban, C; Elango, Kuppanagounder P

    2017-03-01

    The Co(II), Ni(II), Cu(II) and Zn(II) complexes of an aminonaphthoquinone ligand (L) have been prepared and characterized using analytical and spectral techniques. The structures of L and its Zn(II) complex are confirmed by single crystal X-ray diffraction study. The results indicate that Co(II), Ni(II) and Zn(II) complexes possess tetrahedral geometry while Cu(II) complex exhibits square planar structure. The interaction of L and its complexes with CT-DNA reveal that they could interact with CT-DNA through intercalation. The DNA cleavage studies of the L and its complexes indicate that the Cu(II) and Ni(II) complexes cleave the circular form of the DNA relatively to a greater extent than the other complexes. The results of the interaction of these compounds with bovine serum albumin (BSA) indicate that the complexes exhibit a strong binding to BSA over the L. The in vitro anticancer activities indicate that these compounds exhibit substantial activity against human breast (MCF7) and lung cancer (A549) cell lines. The characteristics of apoptosis in cell morphology have been observed using AO/EB and DAPI staining and the results suggest that an apoptotic mode of cell death with these compounds. The overall results and discussion indicate that coordination of metal ions with the ligand enhances the biological activity.

  20. Synthesis, DNA-binding, DNA-photonuclease profiling and antimicrobial activity of novel tetra-aza macrocyclic Ni(II), Co(II) and Cu(II) complexes constrained by thiadiazole.

    Science.gov (United States)

    Vinay Kumar, B; Bhojya Naik, H S; Girija, D; Sharath, N; Pradeepa, S M; Joy Hoskeri, H; Prabhakara, M C

    2012-08-01

    A new tetra-aza macrocyclic ligand, L (C(24)H(16)N(12)O(2)S(4)) and its complexes of type, [MLCl(2)] and [CuL]Cl(2) (where M=Ni(II), Co(II); L=N,N'-(benzene-1,3-diyldi-1,3,4-thiadiazole-5,2-diyl)bis{2-[(5-benzene-1,3-diyl-1,3,4-thiadiazol-2-yl)amino]acetamide}) were synthesized and characterized by the spectral and analytical techniques. An octahedral geometry has been proposed for Ni(II) and Co(II) complexes while Cu(II) complex exhibit a square planar geometry. All the synthesized metal complexes were screened for their in vitro antimicrobial activity against selected species of pathogenic bacteria and fungi. The binding property of the complexes with CT-DNA was studied by absorption spectral analysis, followed by viscosity measurement and thermal denaturation studies. The photo induced cleavage studies revealed that the complexes possess photonuclease property against pUC19 DNA under UV-visible irradiation.

  1. New macrocyclic schiff base complexes incorporating a homopiperazine unit: Synthesis of some Co(II), Ni(II),Cu(II) and Zn(II) complexes and crystal structure and theoretical studies

    Science.gov (United States)

    Keypour, Hassan; Rezaeivala, Majid; Ramezani-Aktij, Ameneh; Bayat, Mehdi; Dilek, Nefise; Ünver, Hüseyin

    2016-07-01

    A new macrocyclic Schiff base ligand, L, was synthesized by condensation reaction of 1,4-bis(2-formylphenyl)homopiperazine and 1,4-diaminobutane in acetonitrile. The Schiff base ligand was characterized by using elemental analyses, FT-IR, 1H, 13C NMR and mass spectroscopic techniques. The metal (II) complexes [ML], were synthesized from the reaction of MCl2.nH2O (M: Co, Ni, Cu and Zn) with Schiff base ligand, L and characterized by elemental analyses and FT-IR. X-ray crystal structure of [CoLCl]+ distorted square pyramidal geometry with an N4Cl core, arising from coordination by the four donor nitrogen atoms from the macrocyclic framework and one Cl atom. It crystallizes triclinic space group, P-1 with a = 7.1777(1) Å, b = 11.0357 (2) Å, c = 15.1520(2) Å, V = 1183.14(3), Z = 2, Dc = 1.556 g cm-3, μ (MoKα) = 0.156 mm-1. Also, the bonding situation between the [MCl]+ and Ligand (L) fragments in [MLCl]ClO4 (M = Co(II), Ni(II), Cu(II), Zn(II)) complexes were carried out by energy-decomposition analysis (EDA). The results showed that there is an increasing trend in the case of ΔEelstat of the complexes by changing the M from Co(II) to Zn(II).

  2. Synthesis, characterization and thermogravimetric analysis of Co(II, Ni(II, Cu(II and Zn(II complexes supported by ONNO tetradentate Schiff base ligand derived from hydrazino benzoxazine

    Directory of Open Access Journals (Sweden)

    N. Kavitha

    2017-01-01

    Full Text Available A new series of Co(II, Ni(II, Cu(II and Zn(II metal complexes of a novel ligand 3-(2-(1-(2,4-DihydroxyPhenylethylidenehydrazinyl-2H-benzo[b][1,4]oxazin-2-one, (DPE-HBO were prepared and characterized. Microwave synthesis of the ligand was also carried out which gave a high increase in its yield within very short time. 3D molecular modeling structure of the ligand is obtained by using ArgusLab software. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analysis, thermal, infrared, electronic spectra, magnetic moments and conductivity measurements. ESR spectrum of Cu(II complex is studied. All the complexes show subnormal magnetic moments. ONNO donor atoms participate in coordination with Cu(II and Zn(II complexes exhibiting octahedral geometry. Co(II and Ni(II complexes behave differently with ONNO donor atoms showing two types of geometries i.e., octahedral and square planar within the same complex.

  3. Synthesis, characterization and biological activity of some new VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based NNO Schiff base derived from 2-aminothiazole

    Science.gov (United States)

    Kalanithi, M.; Kodimunthiri, D.; Rajarajan, M.; Tharmaraj, P.

    2011-11-01

    Coordination compounds of VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) with the Schiff base obtained through the condensation of 2-aminothiazole with 3-formyl chromone were synthesized. The compounds were characterized by 1H, 13C NMR, UV-Vis, IR, Mass, EPR, molar conductance and magnetic susceptibility measurements. The Cu(II) complex possesses tetrahedrally distorted square planar geometry whereas Co(II), Ni(II), and Zn(II) show distorted tetrahedral geometry. The VO(IV) complex shows square pyramidal geometry. The cyclic voltammogram of Cu (II) complex showed a well defined redox couple Cu(II)/Cu(I) with quasireversible nature. The antimicrobial activity against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger was screened and compared to the activity of the ligand. Emission spectrum was recorded for the ligand and the metal(II) complexes. The second harmonic generation (SHG) efficiency was measured and found to have one fourth of the activity of urea. The SEM image of the copper(II) complex implies that the size of the particles is 2 μm.

  4. Estudio del equilibrio y cinética de adsorción de Cd(II), Ni(II) y Cr(VI) usando Quitosano y Quitosano modificado con cobre

    OpenAIRE

    M. Benavente; Castro, S.(INFN Sezione di Bologna, Bologna, Italy); N. Betanco; F. Canelo; X. López; A. García

    2013-01-01

    En este trabajo, se estudió el equilibrio y la cinética de adsorción de Cd(II), Ni(II) en quitosano y Cr(VI) en quitosano modificado con cobre. Para ello, soluciones de iones metálicos a diferentes concentraciones, fueron puestas en contacto con el adsorbente y se agitaron por un período de 3 – 4 h. Al final del proceso, las muestras fueron analizadas en un espectrómetro de absorción atómica. Los datos experimentales del equilibrio de adsorción de los iones metálicos fueron evaluados aplicand...

  5. Zn(II), Cd(II) and Cu(II) complexes of 2,5-bis{N-(2,6-diisopropylphenyl)iminomethyl}pyrrole: synthesis, structures and their high catalytic activity for efficient cyclic carbonate synthesis.

    Science.gov (United States)

    Vignesh Babu, Heeralal; Muralidharan, Krishnamurthi

    2013-01-28

    The syntheses of Zn(II), Cd(II) and Cu(II) complexes of 2,5-bis{N-(2,6-diisopropylphenyl)iminomethyl}pyrrole (DIP(2)pyr)H 1 and their catalytic activities in CO(2) fixation are reported. The structures of these complexes were characterized by IR, (1)H, (13)C NMR and single crystal X-ray diffraction techniques. The catalytic activities of these complexes for the cycloaddition of CO(2) to an epoxide under one atmosphere of pressure and mild temperature conditions to yield cyclic carbonate have been studied. Among the four complexes synthesized, the Zn(II) and Cu(II) complexes were found to be versatile whereas the Cu(II) complex was more selective in the conversion. They were highly effective for the conversion of monosubstituted terminal epoxides, disubstituted terminal and internal epoxides to their corresponding cyclic carbonates with good to high yields.

  6. Spectroscopic (FT-IR, FT-Raman, 1H, 13C NMR, UV/VIS), thermogravimetric and antimicrobial studies of Ca(II), Mn(II), Cu(II), Zn(II) and Cd(II) complexes of ferulic acid

    Science.gov (United States)

    Kalinowska, M.; Piekut, J.; Bruss, A.; Follet, C.; Sienkiewicz-Gromiuk, J.; Świsłocka, R.; Rzączyńska, Z.; Lewandowski, W.

    2014-03-01

    The molecular structure of Mn(II), Cu(II), Zn(II), Cd(II) and Ca(II) ferulates (4-hydroxy-3-methoxycinnamates) was studied. The selected metal ferulates were synthesized. Their composition was established by means of elementary and thermogravimetric analysis. The following spectroscopic methods were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance (13C, 1H NMR) and ultraviolet-visible (UV/VIS). On the basis of obtained results the electronic charge distribution in studied metal complexes in comparison with ferulic acid molecule was discussed. The microbiological study of ferulic acid and ferulates toward Escherichia coli, Bacillus subtilis, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus and Proteus vulgaris was done.

  7. Synthesis of amino functionalized magnetic graphenes composite material and its application to remove Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II) from contaminated water

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xiaoyao [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Du, Bin, E-mail: dubin61@gmail.com [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Wei, Qin, E-mail: sdjndxwq@163.com [School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Yang, Jian [School of Resources and Environment, University of Jinan, Jinan 250022 (China); Hu, Lihua [School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022 (China); Yan, Liangguo; Xu, Weiying [School of Resources and Environment, University of Jinan, Jinan 250022 (China)

    2014-08-15

    Highlights: • Graphenes magnetic composite nanoparticles (Fe{sub 3}O{sub 4}-GS) were used to adsorb metal ions. • The adsorption of metal ions onto Fe{sub 3}O{sub 4}-GS could be well interpreted by the Freundlich equation. • The adsorption of metal ions onto Fe{sub 3}O{sub 4}-GS fit pseudo-second order kinetic model. • Thermodynamic studies illustrated that the adsorption process was endothermic and spontaneous in nature. - Abstract: In the present study, a kind of graphenes magnetic material (Fe{sub 3}O{sub 4}-GS) was prepared by compositing graphene sheet with ferroferric oxide, and shown to be effictive for removing Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II) ions from aqueous solution. The synthesized sorbent was characterized by SEM, TEM, FTIR, XRD, XPS and BET, respectively. The pH{sub ZPC} value of the sorbent was estimated to be 3.5 by alkaline-titration methods. Fe{sub 3}O{sub 4}-GS can be simply recovered from water with magnetic separation at low magnetic field within one minute. The sorption capacities of the metals were 17.29, 27.95, 23.03, 27.83 and 22.07 mg g{sup −1} for Cr(VI), Pb(II), Hg(II), Cd(II) and Ni(II), respectively. Kinetic data showed good correlation with pseudo-second-order equation and the Freundlich model was found to fit for the isotherm data of all the heavy metal ions. It was found that the metals sorption was accomplished mainly via chelation or ion exchange. The results of thermodynamic studies illustrate that the adsorption process was endothermic and spontaneous in nature.

  8. Magnetic, high-field EPR studies and catalytic activity of Schiff base tetranuclear CuII2FeIII2 complexes obtained by direct synthesis.

    Science.gov (United States)

    Nesterova, Oksana V; Chygorin, Eduard N; Kokozay, Vladimir N; Bon, Volodymyr V; Omelchenko, Irina V; Shishkin, Oleg V; Titiš, Ján; Boča, Roman; Pombeiro, Armando J L; Ozarowski, Andrew

    2013-12-28

    Two novel heterometallic complexes [Cu2Fe2(HL(1))2(H2L(1))2]·10DMSO (1) and [Cu2Fe2(HL(2))2(H2L(2))2]·2DMF (2) have been prepared using the open-air reaction of copper powder, iron(II) chloride and DMSO (1) or DMF (2) solutions of the polydentate Schiff base (H4L(1), 1; H4L(2), 2) formed in situ from salicylaldehyde (1) or 5-bromo-salicylaldehyde (2) and tris(hydroxymethyl)aminomethane. Crystallographic analysis revealed that both compounds are based on the centrosymmetric tetranuclear core {Cu(II)2Fe(III)2(μ-O)6} where metal centres are joined by μ-O bridges from the deprotonated ligands forming a nonlinear chain-like arrangement. Variable-temperature (1.8-300 K) magnetic susceptibility measurements of 1 and 2 showed a decrease of the effective magnetic moment value at low temperature, indicative of antiferromagnetic coupling (JCu-Fe/hc = -10.2 cm(-1), JFe-Fe/hc = -10.5 cm(-1) in 1, JCu-Fe/hc = -10.5 cm(-1), JFe-Fe/hc = -8.93 cm(-1) in 2) between the magnetic centres in both compounds. They reveal an exceptionally high catalytic activity in the oxidation of cyclohexane with hydrogen peroxide under mild conditions, with the best observed yield/TON combined values of 36%/596 and 44%/1.1 × 10(3) for 1 and 2, respectively.

  9. Cooperative metal-ligand assisted E/Z isomerization and cyano activation at Cu(II) and Co(II) complexes of arylhydrazones of active methylene nitriles.

    Science.gov (United States)

    Mahmudov, Kamran T; Kopylovich, Maximilian N; Sabbatini, Alessandra; Drew, Michael G B; Martins, Luísa M D R S; Pettinari, Claudio; Pombeiro, Armando J L

    2014-09-15

    New (E/Z)-2-(2-(1-cyano-2-methoxy-2-oxoethylidene)hydrazinyl)benzoic acid (H2L(4)) and known sodium 2-(2-(dicyanomethylene)hydrazinyl)benzenesulfonate (NaHL(1)), 2-(2-(dicyano-methylene)hydrazinyl)benzoic acid (H2L(2)), and sodium (E/Z)-2-(2-(1-cyano-2-methoxy-2-oxoethylidene)hydrazinyl)benzenesulfonate (NaHL(3)) were used in the template synthesis of a series of Cu(II) and Co(II) complexes [Cu(H2O)2L(1a)]·H2O (1), [Cu(H2O)(3-pyon)L(1b)]·H2O (2), [Cu(H2O)(4-pyon)L(1b)] (3), [Co(H2O)((CH3)2NCHO)(μ-L(2a))]2·(CH3)2NCHO (4), [Cu3(μ3-OH)(NO3)(CH3OH)(μ2-X)3(μ2-HL(3))] (5), [Cu(H2O)(py)L(3)]·H2O (6), [Cu(H2O)2(μ-L(4))]6·6H2O (7), [Cu(2-cnpy(b))2(L(1b))2]·2H2O (8), [Cu(2-cnpy(a))2(L(1a))2]·2H2O (9), and [Cu(H2O)(4-cnpy)(L(1a))2] (10), where 3-pyon = 1-(pyridin-3-yl)ethanone, 4-pyon = 1-(pyridin-4-yl)ethanone, py = pyridine, HX = syn-2-pyridinealdoxime, 4-cnpy = 4-cyanopyridine; 2-cnpy(a), 2-cnpy(b), L(1a), L(1b), L(2a) are the ligands derived from nucleophilic attack of methanol (a) or water (b) on a cyano group of 2-cyanopyridine (2-cnpy), L(1) or L(2), respectively, giving the corresponding iminoesters (2-cnpy(a), L(1a) or L(2a)) or carboxamides (2-cnpy(b) or L(1b)). An auxiliary ligand, namely syn-2-pyridinealdoxime or pyridine, acting cooperatively with the metal ion (Cu(II) in this case), induced an E/Z isomerization of the H2L(4) ligand; the E- and Z-isomers were isolated separately and fully characterized (compounds 9 and 10, respectively). A one-pot activation of nitrile groups in different molecules was achieved in the syntheses of 8 and 9. Complexes 1-10 are catalyst precursors for the solvent-free microwave (MW)-assisted selective oxidation of secondary alcohols to the corresponding ketones, with typical yields in the 29-99% range (TOFs up to 4.94 × 10(3) h(-1)) after 30 min of MW irradiation.

  10. Synthesis, characterisation and electrochemical behaviour of Cu(II), Co(II), Ni(II) and Zn(II) complexes derived from acetylacetone and p-anisidine and their antimicrobial activity

    Indian Academy of Sciences (India)

    N Raman; V Muthuraj; S Ravichandran; A Kulandaisamy

    2003-06-01

    Neutral tetradentate N2O2 type complexes of Cu(II), Ni(II), Co(II) and Zn(II) have been synthesised using the Schiff base formed by the condensation of acetylacetone and p-anisidine. Microanalysis, molar conductance, magnetic susceptibility, IR, UV-Vis, 1H NMR, CV and EPR studies have been carried out to determine the structure of the complexes. From the data, it is found that all the complexes possess square-planar geometry. The EPR spectrum of the copper complex in DMSO at 300 K and 77 K was recorded and its salient features are reported. All the title complexes were screened for antimicrobial activity by the well diffusion technique using DMSO as solvent. The minimum inhibitory concentration (MIC) values were calculated at 37°C for a period of 24 h. It has been found that all the complexes are antimicrobially active and show higher activity than the free ligand.

  11. Synthesis, structural characterization, thermal and electrochemical studies of the N,N'-bis[(3,4-dichlorophenyl)methylidene]cyclohexane-1,4-diamine and its Cu(II), Co(II) and Ni(II) metal complexes.

    Science.gov (United States)

    Dolaz, Mustafa; McKee, Vickie; Gölcü, Ayşegül; Tümer, Mehmet

    2009-01-01

    In this study, N,N'-bis[(3,4-dichlorophenyl)methylidene]cyclohexane-1,4-diamine (L) and its Cu(II), Co(II) and Ni(II) complexes were prepared and characterized by the analytical and spectroscopic methods. The analytical data show the composition of the metal complex to be [M(2)L(Cl)(4)(H(2)O)(2)], where L is the Schiff base ligand. The conductance data indicate that all the complexes are non-electrolytes. The compound (L) behaves as a monodentate ligand. But, obtained complexes have binuclear nature. The electrochemical properties of the metal complexes are dependent on reversible, irreversible and quasi-reversible redox waves in the anodic and cathodic regions due to oxidation and reduction of the metal ions. The single crystal of the ligand (L) was obtained from CH(3)CN solution. Space group and crystal system of the ligand are P2(1)/C and monoclinic, respectively.

  12. Synthesis, spectral characterization of biologically active compounds derived from oxalyldihydrazide and 5-tert-Butyl-2-hydroxy-3-(3-phenylpent-3-yl benzaldehyde and their Cu(II, Ni(II and Co(II Complexes

    Directory of Open Access Journals (Sweden)

    Rajeev Johari

    2011-02-01

    Full Text Available A series of Schiff base M(II complexes of the type [HLMClH2O] and [HLMOAcH2O], where M =Cu(II, Ni(II and Co(II have been synthesized by condensation of 3-tert-butl-2-hydroxy-3-(3-phenylpent-3-ylbenzaldehyde and oxalyldihydrazide (2:1 in the presence of divalent metal salt in methanolic medium. Thecomplexes have been characterized with the help of elemental analysis, conductance measurements, magneticmeasurements and their structural configuration have been determined by various spectroscopic (electronic, IR,1H NMR, 13C NMR, GCMS techniques. Electronic and magnetic moments of the complexes indicate that thegeometries of the metal centers were octahedral. These metal complexes were also tested for their antimicrobialactivities to assess their inhibiting potential.

  13. Desulfovibrio frigidus sp. nov. and Desulfovibrio ferrireducens sp. nov., psychrotolerant bacteria isolated from Arctic fjord sediments (Svalbard) with the ability to reduce Fe(III)

    DEFF Research Database (Denmark)

    Vandieken, Verona; Knoblauch, Christian; Jørgensen, Bo Barker

    2006-01-01

    fermentation products such as hydrogen, formate and lactate with sulfate as the electron acceptor. Sulfate could be replaced by sulfite, thiosulfate or elemental sulfur. Poorly crystalline and soluble Fe(III) compounds were reduced in sulfate-free medium, but no growth occurred under these conditions......Strains 18T, 61T and 77 were isolated from two permanently cold fjord sediments on the west coast of Svalbard. The three psychrotolerant strains, with temperature optima at 20-23 degrees C, were able to grow at the freezing point of sea water, -2 degrees C. The strains oxidized important...

  14. Synthesis, Characterization and Thermal Decomposition Studies of Cr(III, Mn(II and Fe(III Complexes of N, N '-Bis[1,3-benzodioxol-5-ylmethylene]butane-1,4-diamine

    Directory of Open Access Journals (Sweden)

    Prasad M. Alex

    2009-01-01

    Full Text Available A bidentate Schiff base ligand namely, N,N'-bis-1,3-benzodioxol-5-ylmethylene]butane-1,4-diamine was synthesised by condensing piperonal (3,4-dioxymethylenebenzaldehyde with butane-1,4-diamine. Cr(III, Mn(II, Fe(III complexes of this chelating ligand were synthesised using acetates, chlorides, bromides, nitrates and perchlorates of these metals. The ligand and the complexes were characterised by elemental analysis, 1H NMR, UV-Vis and IR spectra, conductance and magnetic susceptibility measurements and thermogravimetric analysis. The thermograms of three complexes were analysed and the kinetic parameters for the different stages of decompositions were determined.

  15. Theoretical and experimental studies of two Co(II) and Ni(II) coordination complex with N,O donor 2-chloro-6-{[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-4 nitrophenol ligand

    Science.gov (United States)

    Kusmariya, Brajendra S.; Tiwari, Sandeep; Tiwari, Anjali; Mishra, A. P.; Naikoo, Gowhar Ahmad; Pandit, Umar J.

    2016-07-01

    Here we report two mononuclear Co(II) and Ni(II) complexes of general formula [M(L)2(H2O)].2H2O; {M = CoII & NiII} derived from bidentate 2-chloro-6-{[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-4 nitrophenol ligand (HL). These compounds were characterized by elemental analysis, spectral (FT-IR, electronic and 1H-NMR), molar conductance, thermal, PXRD, SEM and electrochemical studies. Distorted octahedral geometry was proposed around the metal center with ligand (HL). The PXRD and SEM analysis shows the crystalline nature of complexes. The broadening of diffraction peaks were explained in terms of domain size and the lattice strain according to Scherrer and Williamson-Hall method. TG of the synthesized complexes illustrates their general decomposition pattern and thermal stability. The kinetic and thermodynamic parameters viz. activation energy (E∗), pre-exponential factor (Z), entropy of activation (ΔS∗), enthalpy of activation (ΔH∗) and free energy of activation (ΔG∗) of degradation process were also evaluated using Coats-Redfern (C-R), Piloyan-Novikova (P-N) and Horowitz-Metzger (H-M) methods for both complexes assuming first order degradation. The optical band gap values of complexes were found to be in good agreement with calculated HOMO-LUMO energy gap (ΔE) and lie in semiconducting range. The cyclic voltammetric studies of synthesized compounds were carried out in order to examine their electrochemical behavior. In addition theoretical calculations by means of DFT at B3LYP level were incorporated to support the experimental findings.

  16. Co(II), Ni(II), Cu(II) and Zn(II) complexes of tridentate ONO donor Schiff base ligand: Synthesis, characterization, thermal, non-isothermal kinetics and DFT calculations

    Science.gov (United States)

    Kusmariya, Brajendra S.; Mishra, A. P.

    2017-02-01

    We report here four mononuclear Co(II), Ni(II), Cu(II) and Zn(II) coordination compounds of general formula [M(L)2] {L = dcp; M = CoII, CuII & ZnII} and [M(L)(H2O)]·H2O {L = dcp; M = NiII} derived from tridentate 2,4-dichloro-6-{[(3-chloro-2-hydroxy-5-nitrophenyl)imino]methyl}phenol (dcp) ligand. These compounds were synthesized and characterized by elemental analysis, FT-IR, uv-vis, 1H NMR, molar conductance, magnetic moment, thermal, PXRD and SEM-EDX. The Powder X-ray Diffraction patterns and SEM analyses showed the crystalline nature of synthesized compounds. The peak broadening was explained in terms of crystallite size and the lattice strain using Scherrer and Williamson-Hall method. Thermogravimetric analysis was performed to determine the thermal stability of synthesized compounds under nitrogen atmosphere up to 820 K at 10 Kmin-1 heating rate. The kinetic and thermodynamic parameters of thermal decomposition were calculated using Coats-Redfern (C-R), Piloyan-Novikova (P-N) and Horowitz-Metzger (H-M) methods assuming first order degradation. The calculated optical band gap values of complexes were found to be in semiconducting range. To support the experimental findings, and derive some fruitful information viz. frequency calculations, HOMO-LUMO, energy gap (ΔE), molecular electrostatic potential (MEP), spin density, absorption spectra etc.; theoretical calculations by means of DFT and TD-DFT at B3LYP level were incorporated.

  17. Structural and antimicrobial studies of coordination compounds of VO(II, Co(II, Ni(II and Cu(II with some Schiff bases involving 2-amino-4-chlorophenol

    Directory of Open Access Journals (Sweden)

    A. P. MISHRA

    2009-05-01

    Full Text Available Complexes of tailor-made ligands with life essential metal ions may be an emerging area to answer the problem of multi-drug resistance (MDR. The coordination complexes of VO(II, Co(II, Ni(II and Cu(II with the Schiff bases derived from 2-hydroxyacetophenone/2-chlorobenzaldehyde with 2-ami¬no-4-chlorophenol were synthesized and characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, ESR, FAB mass, thermal and magnetic susceptibility measurements. The FAB mass and thermal data show degradation of the complexes. The ligand A (2-hydroxyacetophenone-2amino-4-chlorophenol behaved as tridentate and ligand B (2-chlorobenzylidene-2-amino-4-chlorophenol as bidentate, coordinating through O and N donors. The complexes [VO(A(H2O]×xH2O, [M(A(H2On]×xH2O for Co and Ni, [Cu(A(H2O] and [VO(B2]×xH2O, [M(B2(H2On] for Co and Cu and [Ni(B2] exhibited coordination numbers 4, 5 or 6. X-ray powder diffraction data (a = 11.00417 Å, b = 11.706081 Å and c = 54.46780 Å showed that [Cu(CACP2(H2O2], complex 8, crystallized in the orthorhombic system. The in vitro biological screening effects of the investigated compounds were tested against the bacteria Escherichia coli, Staphylococcus aureus and Streptococcus fecalis and the fungi Aspergillus niger, Trichoderma polysporum and Candida albicans by the serial dilution method. A comparative study of the MIC values of the Schiff base and their [M(B2(H2O2] complexes (Co(II, complex 6 and Cu(II, complex 8, indicated that the metal complexes exhibited a higher or lower antimicrobial activity than 2-chlorobenzylidene-2-amino-4-chlorophenol as the free ligand (B.

  18. Geobacter daltonii sp. nov., an Fe(III)- and uranium(VI)-reducing bacterium isolated from a shallow subsurface exposed to mixed heavy metal and hydrocarbon contamination.

    Science.gov (United States)

    Prakash, Om; Gihring, Thomas M; Dalton, Dava D; Chin, Kuk-Jeong; Green, Stefan J; Akob, Denise M; Wanger, Greg; Kostka, Joel E

    2010-03-01

    An Fe(III)- and uranium(VI)-reducing bacterium, designated strain FRC-32(T), was isolated from a contaminated subsurface of the USA Department of Energy Oak Ridge Field Research Center (ORFRC) in Oak Ridge, Tennessee, where the sediments are exposed to mixed waste contamination of radionuclides and hydrocarbons. Analyses of both 16S rRNA gene and the Geobacteraceae-specific citrate synthase (gltA) mRNA gene sequences retrieved from ORFRC sediments indicated that this strain was abundant and active in ORFRC subsurface sediments undergoing uranium(VI) bioremediation. The organism belonged to the subsurface clade of the genus Geobacter and shared 92-98 % 16S rRNA gene and 75-81 % rpoB gene sequence similarities with other recognized species of the genus. In comparison to its closest relative, Geobacter uraniireducens Rf4(T), according to 16S rRNA gene sequence similarity, strain FRC-32(T) showed a DNA-DNA relatedness value of 21 %. Cells of strain FRC-32(T) were Gram-negative, non-spore-forming, curved rods, 1.0-1.5 microm long and 0.3-0.5 microm in diameter; the cells formed pink colonies in a semisolid cultivation medium, a characteristic feature of the genus Geobacter. The isolate was an obligate anaerobe, had temperature and pH optima for growth at 30 degrees C and pH 6.7-7.3, respectively, and could tolerate up to 0.7 % NaCl although growth was better in the absence of NaCl. Similar to other members of the Geobacter group, strain FRC-32(T) conserved energy for growth from the respiration of Fe(III)-oxyhydroxide coupled with the oxidation of acetate. Strain FRC-32(T) was metabolically versatile and, unlike its closest relative, G. uraniireducens, was capable of utilizing formate, butyrate and butanol as electron donors and soluble ferric iron (as ferric citrate) and elemental sulfur as electron acceptors. Growth on aromatic compounds including benzoate and toluene was predicted from preliminary genomic analyses and was confirmed through successive transfer with

  19. Estudio del equilibrio y cinética de adsorción de Cd(II, Ni(II y Cr(VI usando Quitosano y Quitosano modificado con cobre

    Directory of Open Access Journals (Sweden)

    M. Benavente

    2013-04-01

    Full Text Available En este trabajo, se estudió el equilibrio y la cinética de adsorción de Cd(II, Ni(II en quitosano y Cr(VI en quitosano modificado con cobre. Para ello, soluciones de iones metálicos a diferentes concentraciones, fueron puestas en contacto con el adsorbente y se agitaron por un período de 3 – 4 h. Al final del proceso, las muestras fueron analizadas en un espectrómetro de absorción atómica. Los datos experimentales del equilibrio de adsorción de los iones metálicos fueron evaluados aplicando las isotermas de Langmuir y Freundlich; mientras los datos cinéticos fueron evaluados utilizando los modelos cinéticos de pseudo-primer orden y pseudo-segundo orden. Los resultados del proceso demostraron que los iones fueron eficazmente adsorbidos por el quitosano (Cd y Ni y por el Cu-quitosano (Cr. Además, se comprobó que los datos experimentales del equilibrio de adsorción de Cr(VI y Ni(II se ajustan al modelo de Langmuir; mientras que los datos experimentales del Cd(II fueron mejor ajustados por el modelo de Freundlich. Mediante el uso de la isoterma de Langmuir se determinó la capacidad máxima de adsorción de cromo (29.7 mg/g Cu-quitosano, cadmio (102.0 mg/g quitosano y níquel (83.31 mg/g quitosano. Los resultados de la cinética de adsorción de los iones metálicos mostraron que los datos experimentales fueron mejor ajustados por el modelo de pseudo-segundo orden; es decir, el paso limitante en la velocidad es la reacción de adsorción y no la transferencia de masa.

  20. Polymeric Cd(II), trinuclear and mononuclear Ni(II) complexes of 5-methyl-4-phenyl-1,2,4-triazole-3-thione: Synthesis, structural characterization, thermal behaviour, fluorescence properties and antibacterial activity

    Science.gov (United States)

    Bharty, M. K.; Paswan, S.; Dani, R. K.; Singh, N. K.; Sharma, V. K.; Kharwar, R. N.; Butcher, R. J.

    2017-02-01

    Syntheses of a polymeric Cd(II) complex, [Cd(mptt)2]n (1), a trinuclear Ni(II) complex, [Ni3(μ-mptt)4(μ-H2O)2(H2O)2(ttfa)2]·3H2O (2) and a mononuclear Ni(II) complex [Ni(mptt)2(en)2] (3) have been performed using the ligand 5-methyl-4-phenyl-1,2,4-triazole-3-thione (Hmptt) and nickel(II)/cadmium(II) salts {ttfa = thenoyltrifluroacetonate). The ligand and the complexes have been characterized by various physicochemical methods in addition to their single crystal X-ray structure. The Cd centre in complex 1 adopts a distorted tetrahedral geometry with one sulfur atom and two mptt ligands provide three nitrogen atoms from three triazole units. The sulfur atom of the ligand binds covalently and overall the ligand acts as uninigative N,S/N,N bidentate moiety. The polymeric structure of complex 1 results from the N atoms of the neighboring triazole units coordinating with the Cd(II) centre. The three Ni(II) centres in the trinuclear Ni(II) complex 2 form a linear arrangement and all have six coordinated arrangements. The middle Ni(II) binds with four deprotonated triazole ring nitrogens and two water molecules form two bridges. The terminal Ni(II) centres bind through two thenoyl oxygens, two triazole nitrogens and water molecules that formed bridges with the middle Ni centre. In complex 3, the nickel(II) centre is covalently bonded through two deprotonated triazole ring nitrogens from two ligand moieties and other four sites are occupied by four nitrogens from two bidentate en ligands. Thermogravimetric analyses (TGA) of the complexes indicated for NiO as the final residue. The bioefficacy of the ligand and complexes 2 and 3 have been examined against the growth of bacteria to evaluate their anti-microbial potential. Complex 2 showed high antibacterial activity as compared to the ligand and complex 3. Complexes 1, 2 and 3 are fluorescent materials with maximum emissions at 425, 421 and 396 nm at an excitation wavelength of 323, 348 and 322 nm, respectively.

  1. Adsorption studies of Cd(II) onto Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5} mixed oxide dispersed on silica matrix and its on-line preconcentration and determination by flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Mendonca Costa, Lucimara [Programa de Pos-Graduacao em Quimica da Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva, 700, Alfenas-MG, CEP 37130-000 (Brazil); Ribeiro, Emerson Schwingel [Instituto de Quimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, CEP 21941-909 (Brazil); Segatelli, Mariana Gava [Departamento de Quimica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitario, Londrina-PR, CEP 86051-990 (Brazil); Nascimento, Danielle Raphael do [Instituto de Quimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro-RJ, CEP 21941-909 (Brazil); Midori de Oliveira, Fernanda [Departamento de Quimica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitario, Londrina-PR, CEP 86051-990 (Brazil); Tarley, Cesar Ricardo Teixeira, E-mail: tarley@uel.br [Programa de Pos-Graduacao em Quimica da Universidade Federal de Alfenas, Rua Gabriel Monteiro da Silva, 700, Alfenas-MG, CEP 37130-000 (Brazil); Departamento de Quimica, Universidade Estadual de Londrina, Rod. Celso Garcia Cid, PR 445 Km 380, Campus Universitario, Londrina-PR, CEP 86051-990 (Brazil)

    2011-05-15

    The present study describes the adsorption characteristic of Cd(II) onto Nb{sub 2}O{sub 5}/Al{sub 2}O{sub 3} mixed oxide dispersed on silica matrix. The characterization of the adsorbent has been carried out by infrared spectroscopy (IR), scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS), energy dispersive X-ray fluorescence analysis (EDXRF) and specific surface area (S{sub BET}). From batch experiments, adsorption kinetic of Cd(II) was described by a pseudo-second-order kinetic model. The Langmuir linear isotherm fitted to the experimental adsorption isotherm very well, and the maximum adsorption capacity was found to be 17.88 mg g{sup -1}. Using the effective material, a method for Cd(II) preconcentration at trace level was developed. The method was based on on-line adsorption of Cd(II) onto SiO{sub 2}/Al{sub 2}O{sub 3}/Nb{sub 2}O{sub 5} at pH 8.64, in which the quantitative desorption occurs with 1.0 mol L{sup -1} hydrochloric acid towards FAAS detector. The experimental parameters related to the system were studied by means of multivariate analysis, using 2{sup 4} full factorial design and Doehlert matrix. The effect of SO{sub 4}{sup 2-}, Cu{sup 2+}, Zn{sup 2+} and Ni{sup 2+} foreign ions showed no interference at 1:100 analyte:interferent proportion. Under the most favorable experimental conditions, the preconcentration system provided a preconcentration factor of 18.4 times, consumption index of 1.08 mL, sample throughput of 14 h{sup -1}, concentration efficiency of 4.35 min{sup -1}, linear range from 5.0 up to 35.0 {mu}g L{sup -1} and limits of detection and quantification of 0.19 and 0.65 {mu}g L{sup -1} respectively. The feasibility of the proposed method for Cd(II) determination was assessed by analysis of water samples, cigarette sample and certified reference materials TORT-2 (Lobster hepatopancreas) and DOLT-4 (Dogfish liver).

  2. Use of statistical design of experiments to evaluate the sorption capacity of 7-amine-4-azaheptylsilica and 10-amine- 4-azadecylsilica for Cu(II), Pb(II), and Fe(III) adsorption.

    Science.gov (United States)

    Passos, Camila G; Ribaski, Fernanda S; Simon, Nathália M; dos Santos, Araci A; Vaghetti, Júlio C P; Benvenutti, Edilson V; Lima, Eder Cláudio

    2006-10-15

    7-Amine-4-azaheptylsilica (AAH Si) and 10-amine-4-azadecylsilica (AAD Si) were prepared and used for removal of Cu(II), Pb(II), and Fe(III) from aqueous solutions. Full 2(3) factorial designs with two pseudo-central points were carried out in order to achieve the best conditions of the batch adsorption procedure for metallic ion uptake by the adsorbents. To continue the optimizations, central composite surface design was also employed. These two independent statistical designs of experiments lead to the following conditions: m=30.0 mg of adsorbent; pH 6.0 for Cu(II) and Pb(II), pH 4.0 for Fe(III); t of contact 180 min to guarantee equilibration at higher adsorbate concentration. After optimization of the conditions, isotherms of the metallic ions adsorbed on the AAH Si and AAD Si adsorbents were obtained, which were fitted to nonlinear Langmuir and Freundlich isotherm models.

  3. Synthesis and characterization of dopamine substitue tripodal trinuclear [(salen/salophen/salpropen)M] (Mdbnd Cr(III), Mn(III), Fe(III) ions) capped s-triazine complexes: Investigation of their thermal and magnetic properties

    Science.gov (United States)

    Uysal, Şaban; Koç, Ziya Erdem

    2016-04-01

    In this work, we aimed to synthesize and characterize a novel tridirectional ligand including three catechol groups and its novel tridirectional-trinuclear triazine core complexes. For this purpose, we used melamine (2,4,6-triamino-1,3,5-triazine) (MA) as starting material. 2,4,6-tris(4-carboxybenzimino)-1,3,5-triazine (II) was synthesized by the reaction of an equivalent melamine (I) and three equivalent 4-carboxybenzaldehyde. 4,4‧,4″-((1E,1‧E,1″E)-((1,3,5-triazine-2,4,6-triyl)tris(azanylylidene))tris(methanylylidene))tris(N-(3,4-dihydroxyphenethyl)benzamide) L (IV) was synthesized by the reaction of one equivalent (II) and three equivalent dopamine (3,4-dihydroxyphenethylamine) (DA) by using two different methods. (II, III, IV) and nine novel trinuclear Cr(III), Mn(III) and Fe(III) complexes of (IV) were characterized by means of elemental analyses, 1H NMR, FT-IR spectrometry, LC-MS (ESI+) and thermal analyses. The metal ratios of the prepared complexes were performed using Atomic Absorption Spectrophotometry (AAS). We also synthesized novel tridirectional-trinuclear systems and investigated their effects on magnetic behaviors of [salen, salophen, salpropen Cr(III)/Mn(III)/Fe(III)] capped complexes. The complexes were determined to be low-spin distorted octahedral Mn(III) and Fe(III), and distorted octahedral Cr(III) all bridged by catechol group.

  4. Multi-reverse flow injection analysis integrated with multi-optical sensor for simultaneous determination of Mn(II), Fe(II), Cu(II) and Fe(III) in natural waters.

    Science.gov (United States)

    Youngvises, Napaporn; Suwannasaroj, Kittigan; Jakmunee, Jaroon; AlSuhaimi, Awadh

    2017-05-01

    Multi-reverse flow injection analysis (Mr-FIA) integrated with multi-optical sensor was developed and optimized for the simultaneous determination of multi ions; Mn(II), Fe(II), Cu(II) and Fe(III) in water samples. The sample/standard solutions were propelled making use of a four channels peristaltic pump whereas 4 colorimetric reagents specific for the metal ions were separately injected in sample streams using multi-syringe pump. The color zones that formed in the individual mixing coils were then streamed into multi-channels spectrometer, which comprised of four flows through cell and four pairs of light emitting diode and photodiode, whereby signals were measured concurrently. The linearity range (along with detection limit, µgL(-1)) was 0.050-3.0(16), 0.30-2.0 (11), 0.050-1.0(12) and 0.10-1.0(50)mgL(-1), for Mn(II), Fe(II), Cu(II) and Fe(III), respectively. In the interim, the correlation coefficients were 0.9924-0.9942. The percentages relative standard deviation was less than 3. The proposed system was applied successfully to determine targeted metal ions simultaneously in natural water with high sample throughput and low reagent consumption, thus it satisfies the criteria of Green Analytical Chemistry (GAC) and its goals.

  5. Solid-phase extraction of Fe(III), Pb(II) and Cr(III) in environmental samples on amberlite XAD-7 and their determinations by flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Divrikli, Umit [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, Denizli 20020 (Turkey)], E-mail: udivrikli@pamukkale.edu.tr; Akdogan, Abdullah [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, Denizli 20020 (Turkey); Soylak, Mustafa [Erciyes University, Faculty of Arts and Science, Department of Chemistry, Kayseri 38039 (Turkey); Elci, Latif [Pamukkale University, Faculty of Arts and Science, Department of Chemistry, Denizli 20020 (Turkey)

    2007-10-22

    This paper describes a simple and accurate procedure for preconcentration of trace amounts of Fe(III), Pb(II) and Cr(III) ions. The preconcentration procedure is based on retention of p-xylenol blue chelates on Amberlite XAD-7. The analytes retained were eluted from Amberlite XAD-7 by using 1 mol L{sup -1} HCl. The influences of the analytical parameters including amounts of reagents, pH and type of eluent were also investigated. The detection limits of Fe, Pb and Cr were found to be 3.07, 18.6 and 3.27 {mu}g L{sup -1}, respectively. The accuracy of the procedure was checked by the analysis of an electrolytic copper wire sample. The relative error was less than 5%. The presented method was applied to the determination of Fe(III), Pb(II) and Cr(III) in water samples from Denizli, Turkey with good results such as recoveries more than 95%, relative standard deviations below 10%.

  6. Solid-phase extraction of Fe(III), Pb(II) and Cr(III) in environmental samples on amberlite XAD-7 and their determinations by flame atomic absorption spectrometry.

    Science.gov (United States)

    Divrikli, Umit; Akdogan, Abdullah; Soylak, Mustafa; Elci, Latif

    2007-10-22

    This paper describes a simple and accurate procedure for preconcentration of trace amounts of Fe(III), Pb(II) and Cr(III) ions. The preconcentration procedure is based on retention of p-xylenol blue chelates on Amberlite XAD-7. The analytes retained were eluted from Amberlite XAD-7 by using 1 mol L(-1) HCl. The influences of the analytical parameters including amounts of reagents, pH and type of eluent were also investigated. The detection limits of Fe, Pb and Cr were found to be 3.07, 18.6 and 3.27 microg L(-1), respectively. The accuracy of the procedure was checked by the analysis of an electrolytic copper wire sample. The relative error was less than 5%. The presented method was applied to the determination of Fe(III), Pb(II) and Cr(III) in water samples from Denizli, Turkey with good results such as recoveries more than 95%, relative standard deviations below 10%.

  7. The nature of the intermediates in the reactions of Fe(III)- and Mn(III)-microperoxidase-8 with H(2)O(2): a rapid kinetics study.

    Science.gov (United States)

    Primus, Jean-Louis; Grunenwald, Sylvie; Hagedoorn, Peter-Leon; Albrecht-Gary, Anne-Marie; Mandon, Dominique; Veeger, Cees

    2002-02-20

    Kinetic studies were performed with microperoxidase-8 (Fe(III)MP-8), the proteolytic breakdown product of horse heart cytochrome c containing an octapeptide linked to an iron protoporphyrin IX. Mn(III) was substituted for Fe(III) in Mn(III)MP-8. The mechanism of formation of the reactive metal-oxo and metal-hydroperoxo intermediates of M(III)MP-8 upon reaction of H(2)O(2) with Fe(III)MP-8 and Mn(III)MP-8 was investigated by rapid-scan stopped-flow spectroscopy and transient EPR. Two steps (k(obs1) and k(obs2)) were observed and analyzed for the reaction of hydrogen peroxide with both catalysts. The plots of k(obs1) as function of [H(2)O(2)] at pH 8.0 and pH 9.1 for Fe(III)MP-8, and at pH 10.2 and pH 10.9 for Mn(III)MP-8, exhibit saturation kinetics, which reveal the accumulation of an intermediate. Double reciprocal plots of 1/k(obs1) as function of 1/[H(2)O(2)] at different pH values reveal a competitive effect of protons in the oxidation of M(III)MP-8. This effect of protons is confirmed by the linear dependence of 1/k(obs1) on [H(+)] showing that k(obs1) increases with the pH. The UV-visible spectra of the intermediates formed at the end of the first step (k(obs1)) exhibit a spectrum characteristic of a high-valent metal-oxo intermediate for both catalysts. Transient EPR of Mn(III)MP-8 incubated with an excess of H(2)O(2), at pH 11.5, shows the detection of a free radical signal at g approximately equal to 2 and of a resonance at g approximately equal to 4 characteristic of a Mn(IV) (S = 3/2) species. On the basis of these results, the following mechanism is proposed: (i) M(III)MP-8-OH(2) is deprotonated to M(III)MP-8-OH in a rapid preequilibrium step, with a pK(a) = 9.2 +/- 0.9 for Fe(III)MP-8 and a pK(a) = 11.2 +/- 0.3 for Mn(III)MP-8; (ii) M(III)MP-8-OH reacts with H(2)O(2) to form Compound 0, M(III)MP8-OOH, with a second-order rate constant k(1) = (1.3 +/- 0.6) x 10(6) M(-1) x s(-1) for Fe(III)MP-8 and k(1) = (1.6 +/- 0.9) x 10(5) M(-1) x s(-1) for Mn

  8. A new nanohybrid material constructed from Keggin-type polyoxometalate and Cd(II) semicarbazone Schiff base complex with excellent adsorption properties for the removal of cationic dye pollutants

    Science.gov (United States)

    Farhadi, Saeed; Amini, Mostafa M.; Dusek, Michal; Kucerakova, Monika; Mahmoudi, Farzaneh

    2017-02-01

    A novel nanohybrid material containing a Cd(II) semicarbazone Schiff base complex and phosphomolybdic acid, [Cd(H2L+)6][H2L]+4[PMo12O40]4·18CH3OH·4H2O (1), [HL = pyridine-2-carbaldehyde semicarbazone] was prepared by a simple sonochemical route and characterized by 1HNMR, 13CNMR, FT-IR, UV-vis, PXRD, FESEM, TG-DTA and BET-BJH surface area analysis. Also the single crystal 1, was characterized by single-crystal X-ray diffraction analysis. It crystallizes in the triclinic system with space group P-1 and is assembled into 3D supramolecular structure via hydrogen intermolecular interactions. The nanohybrid 1 was tested for the adsorption and removal of organic dyes such as methylene blue (MB), Rhodamine B (RhB) and methyl orange (MO) from aqueous solutions. The effects of parameters such as the dosage of adsorbent, the initial concentration and pH of dye solution were investigated on the removal efficiency of methylene blue. The nanohybrid 1 exhibited excellent adsorption ability towards cationic dyes. Moreover, it could be easily separated from the reaction solution and recycled up to three times without significant loss of adsorption activity.

  9. Cyanide bridged hetero-metallic polymeric complexes: Syntheses, vibrational spectra, thermal analyses and crystal structures of complexes [M(1,2-dmi)2Ni(μ-CN)4]n (M = Zn(II) and Cd(II))

    Science.gov (United States)

    Kürkçüoğlu, Güneş Süheyla; Sayın, Elvan; Şahin, Onur

    2015-12-01

    Two cyanide bridged hetero-metallic complexes of general formula, [M(1,2-dmi)2Ni(μ-CN)4]n (1,2-dmi = 1,2-dimethylimidazole and M = Zn(II) or Cd(II)) have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal analyses and elemental analyses. The crystallographic analyses reveal that the complexes, [Zn(1,2-dmi)2Ni(μ-CN)4] (1) and [Cd(1,2-dmi)2Ni(μ-CN)4] (2), have polymeric 2D networks. In the complexes, four cyanide groups of [Ni(CN)4]2- coordinated to the adjacent M(II) ions and distorted octahedral geometries of complexes are completed by two nitrogen atoms of trans 1,2-dmi ligands. The structures of 1 and 2 are similar and linked via intermolecular hydrogen bonding, C-H⋯Ni interactions to give rise to 3D networks. Vibration assignments are given for all the observed bands and the spectral features also supported to the crystal structures of heteronuclear complexes. The FT-IR and Raman spectra of the complexes are very much consistent with the structural data presented.

  10. Highly efficient simultaneous ultrasonic-assisted adsorption of Pb(II), Cd(II), Ni(II) and Cu (II) ions from aqueous solutions by graphene oxide modified with 2,2'-dipyridylamine: Central composite design optimization.

    Science.gov (United States)

    Zare-Dorabei, Rouholah; Ferdowsi, Somayeh Moazen; Barzin, Ahmad; Tadjarodi, Azadeh

    2016-09-01

    In present work, a graphene oxide chemically modified with 2,2'-dipyridylamine (GO-DPA), was synthesized by simple, fast and low-cost process for the simultaneous adsorption of four toxic heavy metals, Pb(II), Cd(II), Ni(II) and Cu(II), from aqueous solutions. The synthesized adsorbent was characterized by FT-IR, XRD, XPS, SEM and AFM measurements. The effects of variables such as pH solution, initial ion concentrations, adsorbent dosage and sonicating time were investigated on adsorption efficiency by rotatable central composite design. The optimum conditions, specified as 8mg of adsorbent, 20mgL(-1) of each ion at pH 5 and short time of 4min led to the achievement of a high adsorption capacities. Ultrasonic power had important role in shortening the adsorption time of ions by enhancing the dispersion of adsorbent in solution. The adsorption kinetic studies and equilibrium isotherms for evaluating the mechanism of adsorption process showed a good fit to the pseudo-second order and Langmuir model, respectively. The maximum adsorption capacities (Qm) of this adsorbent were 369.749, 257.201, 180.893 and 358.824mgg(-1) for lead, cadmium, nickel and copper ions, respectively. The removal performance of adsorbent on the real wastewater samples also showed the feasibility of adsorbent for applying in industrial purposes.

  11. Preparation and Spectral Properties of Mixed-Ligand Complexes of VO(IV, Ni(II, Zn(II, Pd(II, Cd(II and Pb(II with Dimethylglyoxime and N-acetylglycine

    Directory of Open Access Journals (Sweden)

    Shayma A. Shaker

    2010-01-01

    Full Text Available A number of mixed-ligand complexes of the general formula [M(D(G] where D=dimethylglyoximato monoanion, G=N-acetylglycinato and M=VO(IV, Ni(II, Zn(II, Pd(II, Cd(II and Pb(II were prepared. Each complex was characterized by elemental analysis, determination of metal, infrared spectra, electronic spectra, (1H and 13C NMR spectra, conductivity and magnetic moments. All these complexes were not soluble in some of the organic solvent but highly soluble in dimethylformamide. The conductivity data showed the non-electrolytic nature of the complexes. The electronic spectra exhibited absorption bands in the visible region caused by the d-d electronic transition such as VO(IV, Ni(II and Pd(II. The IR and (1H, 13C NMR spectra which have indicate that the dimethylglyoxime was coordinated with the metal ions through the N and O atoms of the oxime group and N-acetylglycine was coordinated with metal ions through the N atom and terminal carboxyl oxygen atom.

  12. Adsorption of Cu(II), Zn(II), Cd(II) and Pb(II) by dead Avena fatua biomass and the effect of these metals on their growth.

    Science.gov (United States)

    Areco, María Mar; Saleh-Medina, Leila; Trinelli, María Alcira; Marco-Brown, Jose Luis; Dos Santos Afonso, María

    2013-10-01

    The biosorption of copper(II), zinc(II), cadmium(II) and lead(II) from aqueous solutions by dead Avena fatua biomass and the effect of these metals on the growth of this wild oat were investigated. Pseudo-first- and second-order and intra-particle diffusion models were applied to describe the kinetic data and to evaluate the rate constants. The adsorption kinetics of all the metals follows a pseudo-second-order model. The adsorption capacity was determined, and the Freundlich and Langmuir models were applied. The experimental data obtained for all the metals are best described by the Langmuir model. A. fatua was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and zeta potential. The results obtained evidence the presence of Zn(II), Cu(II), Cd(II) or Pb(II) on the surface of the weed. The growth of A. fatua was affected by the presence of all metals. The decrease in the growth rate with increasing metal concentration was more noticeable for zinc.

  13. Preparation, spectroscopic, thermal, antihepatotoxicity, hematological parameters and liver antioxidant capacity characterizations of Cd(II), Hg(II), and Pb(II) mononuclear complexes of paracetamol anti-inflammatory drug

    Science.gov (United States)

    El-Megharbel, Samy M.; Hamza, Reham Z.; Refat, Moamen S.

    2014-10-01

    Keeping in view that some metal complexes are found to be more potent than their parent drugs, therefore, our present paper aimed to synthesized Cd(II), Hg(II) and Pb(II) complexes of paracetamol (Para) anti-inflammatory drug. Paracetamol complexes with general formula [M(Para)2(H2O)2]·nH2O have been synthesized and characterized on the basis of elemental analysis, conductivity, IR and thermal (TG/DTG), 1H NMR, electronic spectral studies. The conductivity data of these complexes have non-electrolytic nature. Comparative antimicrobial (bacteria and fungi) behaviors and molecular weights of paracetamol with their complexes have been studied. In vivo the antihepatotoxicity effect and some liver function parameters levels (serum total protein, ALT, AST, and LDH) were measured. Hematological parameters and liver antioxidant capacities of both Para and their complexes were performed. The Cd2+ + Para complex was recorded amelioration of antioxidant capacities in liver homogenates compared to other Para complexes treated groups.

  14. A two-dimensional CdII coordination polymer: poly[diaqua[μ3-5,6-bis(pyridin-2-ylpyrazine-2,3-dicarboxylato-κ5O2:O3:O3,N4,N5]cadmium

    Directory of Open Access Journals (Sweden)

    Monserrat Alfonso

    2016-09-01

    Full Text Available The reaction of 5,6-bis(pyridin-2-ylpyrazine-2,3-dicarboxylic acid with cadmium dichloride leads to the formation of the title two-dimensional coordination polymer, [Cd(C16H8N4O4(H2O2]n. The metal atom is sevenfold coordinated by one pyrazine and one pyridine N atom, two water O atoms, and by two carboxylate O atoms, one of which bridges two CdII atoms to form a Cd2O2 unit situated about a centre of inversion. Hence, the ligand coordinates to the cadmium atom in an N,N′,O-tridentate and an O-monodentate manner. Within the polymer network, there are a number of O—H...O hydrogen bonds present, involving the water molecules and the carboxylate O atoms. There are also C—H...N and C—H...O hydrogen bonds present. In the crystal, the polymer networks lie parallel to the bc plane. They are aligned back-to-back along the a axis with the non-coordinating pyridine rings directed into the space between the networks.

  15. A study on the use of nano/micro structured goethite and hematite as adsorbents for the removal of Cr(III, Co(II, Cu(II, Ni(II, and Zn(II metal ions from aqueous solutions.

    Directory of Open Access Journals (Sweden)

    Hala Hafez

    2012-06-01

    Full Text Available Numerous adsorbents for the removal of heavy metals from aqueous solutions are in various stages of research. The main goal for most of this research is to develop low-cost and environmentally friendly materials for the removal of heavy metals from contaminated groundwater, surface water, and drinking water. Materials that have ion exchange sites are expected to be able to efficiently remove heavy metals from water. Iron oxides, especially in the micro/nano structured forms, are good candidates for the removal of toxic heavymetal ions from water due to their structural properties. In the present work the efficiency of synthesized micro/nano particles of goethite and hematite for the removal of Cr(III, Co(II , Cu(II, Ni(II and Zn(II ions from water was compared. The absorbent capability of goethite as a function of pH, contact time, and initialmetal ion concentration was studied. The results showed that maximum absorption for all metal ions using goethite occurred at a pH=5.3, which was a common trend for all metal ions. At this pH and after one hour contact time goethite was able to adsorb about 100% of the Cu ions (50mg/g, 85% (42.5 mg/g of the Ni ions, 70% (35mg/g of the Cr and Co ions and 60% (30 mg/g of Zn ions from the solutions. Whereas and under the same conditions hematite was able to adsorb 20% (10mg/g of the Cu ions, 85% (42.5mg/g of the Ni ions, 95% (47.5mg/g of the Cr ions, 80% (40mg/g of the Zn ions, and 70% (35mg/g of the Co ions. Both oxides are equally efficient for the removal of Co(II and Ni(II from water. However, goethite is a much more efficient candidate than hematite for the removal of Cu(II,while hematite is more efficient adsorbent for Zn(II and Cr(III. The adsorption affinity of the five metallic cations to goethite is Cu > Ni > Co ~ Cr > Zn, whereas the adsorption affinity of the cations to hematite is Cr > Ni > Zn > Co > Cu. Under the conditions used in the batch experiments (mass of goethite 2g/l maximumadsorption of

  16. Synthesis, structural, thermal studies and biological activity of a tridentate Schiff base ligand and their transition metal complexes.

    Science.gov (United States)

    Abd El-halim, Hanan F; Omar, M M; Mohamed, Gehad G

    2011-01-01

    Schiff base (L) ligand is prepared via condensation of pyridine-2,6-dicarboxaldehyde with -2-aminopyridine. The ligand and its metal complexes are characterized based on elemental analysis, mass, IR, solid reflectance, magnetic moment, molar conductance, and thermal analyses (TG, DTG and DTA). The molar conductance reveals that all the metal chelates are non-electrolytes. IR spectra shows that L ligand behaves as neutral tridentate ligand and bind to the metal ions via the two azomethine N and pyridine N. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral (Cr(III), Fe(III), Co(II), Ni(II), Cu(II), and Th(IV)) and tetrahedral (Mn(II), Cd(II), Zn(II), and UO2(II)). The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, ΔH*, ΔS* and ΔG* are calculated from the DTG curves using Coats-Redfern method. The synthesized ligand, in comparison to their metal complexes also was screened for its antibacterial activity against bacterial species, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus pyogones and Fungi (Candida). The activity data shows that the metal complexes to be more potent/antibacterial than the parent Schiff base ligand against one or more bacterial species.

  17. Synthesis of metal complexes involving Schiff base ligand with methylenedioxy moiety: spectral, thermal, XRD and antimicrobial studies.

    Science.gov (United States)

    Sundararajan, M L; Jeyakumar, T; Anandakumaran, J; Karpanai Selvan, B

    2014-10-15

    Metal complexes of Zn(II), Cd(II), Ni(II), Cu(II), Fe(III), Co(II), Mn(II) Hg(II), and Ag(I) have been synthesized from Schiff base ligand, prepared by the condensation of 3,4-(methylenedioxy)aniline and 5-bromo salicylaldehyde. All the compounds have been characterized by using elemental analysis, molar conductance, FT-IR, UV-Vis, (1)H NMR, (13)C NMR, mass spectra, powder XRD and thermal analysis (TG/DTA) technique. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). The FT-IR, (1)H NMR, (13)C NMR and UV-Vis spectral data suggest that the ligand coordinate to the metal atom by imino nitrogen and phenolic oxygen as bidentate manner. Mass spectral data further support the molecular mass of the compounds and their structure. Powder XRD indicates the crystalline state and morphology of the ligand and its metal complexes. The thermal behaviors of the complexes prove the presence of lattice as well as coordinated water molecules in the complexes. Melting point supports the thermal stability of all the compounds. The in vitro antimicrobial effects of the synthesized compounds were tested against five bacterial and three fungal species by well diffusion method. Antioxidant activities have also been performed for all the compounds. Metal complexes show more biological activity than the Schiff base.

  18. Spectroscopic, thermal, antimicrobial and molecular modeling studies of mononuclear pentafunctional Schiff base metal chelates derived from 5-acetyl-4-hydroxy-2H-1,3-thiazine-2,6(3H)-dione

    Science.gov (United States)

    Adly, Omima M. I.; Taha, Ali; Fahmy, Shery A.

    2015-03-01

    A new pentafunctional N3O2 Schiff base, H2L ligand, and its metal chelates with Cu(II), Ni(II), Co(II), VO(IV), Zn(II), Cd(II), Ce(III), Cr(III), Fe(III) and UO2(VI) have been synthesized and characterized by elemental analysis, spectral, molar conductance, magnetic and thermal gravimetric studies. The results showed that the complexes have octahedral geometry except UO2 complex which has pentagonal bipyramidal arrangement. The TGA analyses suggest high stability for most complexes followed by thermal decomposition in different steps. The kinetic and thermodynamic parameters for decomposition steps of metal complexes thermograms have been calculated. Molecular orbital calculations were performed for the ligand and its metal complexes by means of hyperchem 7.52 program on the bases of semiempirical PM3 level and the results were correlated with the experimental data. The antimicrobial activity of the synthesized compounds were tested in vitro against some Gram-positive and Gram-negative bacteria; yeast and fungus strains and the results were discussed in terms of extended Lewis acid-base interactions.

  19. Synthesis, spectral, computational and thermal analysis studies of metalloceftriaxone antibiotic

    Science.gov (United States)

    Masoud, Mamdouh S.; Ali, Alaa E.; Elasala, Gehan S.

    2015-03-01

    Binary ceftriaxone metal complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II) and six mixed metals complexes of (Fe, Cu), (Fe, Co), (Co, Ni), (Co, Cu), (Ni, Cu) and (Fe, Ni) were synthesized and characterized by elemental analysis, IR, electronic spectra, magnetic susceptibility and ESR spectra. The studies proved that the ligand has different combination modes and all complexes were of octahedral geometry. Molecular modeling techniques and quantum chemical methods have been performed for ceftriaxone to calculate charges, bond lengths, bond angles, dihedral angles, electronegativity (χ), chemical potential (μ), global hardness (η), softness (σ) and the electrophilicity index (ω). The thermal decomposition of the prepared metals complexes was studied by TGA, DTA and DSC techniques. The kinetic parameters and the reaction orders were estimated. The thermal decomposition of all the complexes ended with the formation of metal oxides and carbon residue as a final product except in case of Hg complex, sublimation occurs at the temperature range 297.7-413.7 °C so, only carbon residue was produced during thermal decomposition. The geometries of complexes may be altered from Oh to Td during the thermal decomposition steps. Decomposition mechanisms were suggested.

  20. Metal complexes of N'-(2-hydroxy-5-phenyldiazenyl benzylideneisonicotinohydrazide: Synthesis, spectroscopic characterization and antimicrobial activity

    Directory of Open Access Journals (Sweden)

    El-Tabl Abdou S.

    2013-01-01

    Full Text Available A new series of Cu(II, Ni(II, Co(II, Mn(II, Zn(II, Cd(II, Hg(II , VO(II, UO2(II , Fe(III and Ru(III complexes of N'-(2-hydroxy-5- phenyldiazenylbenzylideneisonicotinohydrazide(H2L have been synthesized and characterized by elemental,1H-NMR, IR, UV-Vis., ESR, magnetic, thermogravimetric analyses(TG and conductivity measurements. The spectral data show that, the ligand behaves as a neutral bidentate, (2, (4, (5, (6 and (14, monobasic bidentate, (3, (7, (8, (9 and (10, monobasic tridentate (11 and (16 or dibasic tridentate (12, (13 and (15 bonded to metal ions via the carbonyl oxygen atom in ketonic or enolic form, azomethine nitrogen atom and/or deprotonated phenolic hydroxyl oxygen. The ESR spectrum of solid vanadyl(II, complex (2 shows axially anisotropic spectrum with eight lines in the low field region and g?>g||, A||>>A?relationship, which is characteristics of distorted octahedral structure with dxy ground state. However, copper(II complexes (4, (5 and (6 and manganese(II complex (10 show an isotropic type while the copper(II complexes (3 and (7show an axial symmetry type with g||>g?>ge indicating a covalent bond character. The antibacterial and antifungal activities of the ligand and its metal complexes show mild activity compared with standard drugs (Tetracycline for bacteria and amphotricene B for fungi.

  1. 4-{[(2-Hydroxyphenyl)imino]methyl}-1,2-benzenediol (HIMB) anchored Amberlite XAD-16: Preparation and applications as metal extractants.

    Science.gov (United States)

    Venkatesh, Gopalan; Singh, Ajai K

    2007-01-15

    Amberlite XAD-16 was loaded with 4-{[(2-hydroxyphenyl)imino]methyl}-1,2-benzenediol (HIMB) via azo linker and the resulting resin AXAD-16-HIMB explored for enrichment of Zn(II), Mn(II), Ni(II), Pb(II), Cd(II), Cu(II), Fe(III) and Co(II) in the pH range 5.0-8.0. The sorption capacity was found between 56 and 415mumolg(-1) and the preconcentration factors from 150 to 300. Tolerance limits for foreign species are reported. The kinetics of sorption is not slow, as t(1/2) is

  2. Synthesis, Spectroscopic Characterisation, and Biopotential and DNA Cleavage Applications of Mixed Ligand 4-N,N-Dimethylaminopyridine Metal Complexes

    Directory of Open Access Journals (Sweden)

    C. Surendra Dilip

    2013-01-01

    Full Text Available The mixed ligand transition metal complexes of 4-N,N-dimethylaminopyridine (DP and chloride as primary and secondary ligands with the general formula [M(DP3Cl3]; M = Cr(III and Fe(III; [M′(DP4Cl2]M′ = Co(II, Ni(II, Cu(II, and Cd(II were synthesized in a microwave oven. The complexes were characterized by FT-IR and UV, 1HNMR, 13CNMR spectra, TG/DTG, and various physicoanalytical techniques. From the magnetic moment measurements and the electronic spectral data, a distorted octahedral geometry was proposed for the complexes. The complexes express similar trend of thermal behaviour such that they lose water of hydration initially with the subsequent emission of organic and inorganic fragments and leave left the metal oxides as residue. The activation thermodynamic parameters, such as , , , and of the metal complexes, illustrate the spontaneous formation of the complexes. The antimicrobial studies against various pathogenic bacterial and fungal serums insist on that the enhanced potential of the complexes over their ligand and their biopotential properties increases with concentration. The DNA interaction of the synthesized complexes on CT-DNA was investigated by UV-Vis spectroscopy, viscosity, thermal denaturation, and electroanalytical experiments and their binding constants ( were also calculated.

  3. Synthesis, spectral characterization, molecular modeling and antimicrobial activity of new potentially N2O2 Schiff base complexes

    Science.gov (United States)

    Adly, Omima M. I.; Taha, Ali; Fahmy, Shery A.

    2013-12-01

    Metal complexes of a new potentially tetradentate symmetrical Schiff base ligand (H2L) with Cu(II), Ni(II), Co(II), VO(IV), Zn(II), Cd(II), Ce(III), Fe(III) and UO2(VI) metal ions have been synthesized and characterized based on their elemental analyses, spectral (IR, UV-Vis, 1H NMR and mass spectra), magnetic and molar conductance studies as well as thermal gravimetric analysis (TGA). The synthesized complexes have the general formula [MHxL(H2O)yXn]: x = 0-1, y = 0-4 and n = 0-1; where: L = dianion of 6-hydroxy-5-[N-(2-{[(1E)-1-(6-hydroxy-2,4-dioxo-3,4-dihydro-2H-1,3-thiazin-5-yl)ethylidene]amino}ethyl) ethanimidoyl]-2H-1,3-thiazine-2,4(3H)-dione and X = nitrate or sulphate anion. The ligand behaves as diabasic tetradentate N2O2 sites, except in cases of Co(II), VO(IV) and UO2(VI) metal ions, it behaves as monobasic tetradentate Schiff base ligand. The metal complexes exhibited square planar, square-pyramidal and octahedral geometrical arrangements except for Ce(III) and UO2(VI) complexes, they are octa-coordinated. The Coats-Redfern equation was used to calculate the kinetic and thermodynamic parameters for the different thermal decomposition stages of some complexes. Structural parameters of the ligand and its metal complexes have been theoretically computed on the basis of semiemperical PM3 level, and the results were correlated with their experimental data. The antimicrobial activities of the ligand and its metal complexes were tested against some Gram-positive and Gram-negative bacteria; and fungus strain and the results were discussed.

  4. Tetranuclear hetero-metal [Co(II)2Ln(III)2] (Ln = Gd, Tb, Dy, Ho, La) complexes involving carboxylato bridges in a rare μ4-η(2):η(2) mode: synthesis, crystal structures, and magnetic properties.

    Science.gov (United States)

    Abtab, Sk Md Towsif; Majee, Mithun Chandra; Maity, Manoranjan; Titiš, Ján; Boča, Roman; Chaudhury, Muktimoy

    2014-02-01

    A new family of 3d-4f heterometal 2 × 2 complexes [Co(II)2(L)2(PhCOO)2Ln(III)2(hfac)4] (1-5) (Ln = Gd (compound 1), Tb (compound 2), Dy (compound 3), Ho (compound 4), and La (compound 5)) have been synthesized in moderate yields (48-63%) following a single-pot protocol using stoichiometric amounts (1:1 mol ratio) of [Co(II)(H2L)(PhCOO)2] (H2L = N,N'-dimethyl-N,N'-bis(2-hydroxy-3,5-dimethylbenzyl)ethylenediamine) as a metalloligand and [Ln(III)(hfac)3(H2O)2] (Hhfac = hexafluoroacetylacetone) as a lanthanide precursor compound. Also reported with this series is the Zn-Dy analog [Zn(II)2(L)2(PhCOO)2Dy(III)2(hfac)4] 6 to help us in understanding the magnetic properties of these compounds. The compounds 1-6 are isostructural. Both hexafluoroacetylacetonate and benzoate play crucial roles in these structures as coligands in generating a tetranuclear core of high thermodynamic stability through a self-assembly process. The metal centers are arranged alternately at the four corners of this rhombic core, and the carboxylato oxygen atoms of each benzoate moiety bind all of the four metal centers of this core in a rare μ4-η(2):η(2) bridging mode as confirmed by X-ray crystallography. The magnetic susceptibility and magnetization data confirm a paramagnetic behavior, and no remnant magnetization exists in any of these compounds at vanishing magnetic field. The metal centers are coupled in an antiferromagnetic manner in these compounds. The [Co(II)2Dy(III)2] compound exhibits a slow magnetic relaxation below 6 K, as proven by the AC susceptibility measurements; the activation energy reads U/kB = 8.8 K (τ0 = 2.0 × 10(-7) s) at BDC = 0, and U/kB = 7.8 K (τ0 = 3.9 × 10(-7) s) at BDC = 0.1 T. The [Zn(II)2Dy(III)2] compound also behaves as a single-molecule magnet with U/kB = 47.9 K and τ0 = 2.75 × 10(-7) s.

  5. Metal-Based Antibacterial and Antifungal Agents: Synthesis, Characterization, and In Vitro Biological Evaluation of Co(II, Cu(II, Ni(II, and Zn(II Complexes with Amino Acid-Derived Compounds

    Directory of Open Access Journals (Sweden)

    Zahid H. Chohan

    2006-01-01

    Full Text Available A series of antibacterial and antifungal amino acid-derived compounds and their cobalt(II, copper(II, nickel(II, and zinc(II metal complexes have been synthesized and characterized by their elemental analyses, molar conductances, magnetic moments, and IR, and electronic spectral measurements. Ligands (L1–(L5 were derived by condensation of β-diketones with glycine, phenylalanine, valine, and histidine and act as bidentate towards metal ions (cobalt, copper, nickel, and zinc via the azomethine-N and deprotonated-O of the respective amino acid. The stoichiometric reaction between the metal(II ion and synthesized ligands in molar ratio of M: L (1: 1 resulted in the formation of the metal complexes of type [M(L(H2O4]Cl (where M = Co(II, Cu(II, and Zn(II and of M: L (1: 2 of type [M(L2(H2O2] (where M = Co(II, Cu(II, Ni(II, and Zn(II. The magnetic moment data suggested for the complexes to have an octahedral geometry around the central metal atom. The electronic spectral data also supported the same octahedral geometry of the complexes. Elemental analyses and NMR spectral data of the ligands and their metal(II complexes agree with their proposed structures. The synthesized ligands, along with their metal(II complexes, were screened for their in vitro antibacterial activity against four Gram-negative (Escherichia coli, Shigella flexeneri, Pseudomonas aeruginosa, and Salmonella typhi and two Gram-positive (Bacillus subtilis and Staphylococcus aureus bacterial strains and for in vitro antifungal activity against Trichophyton longifusus, Candida albicans, Aspergillus flavus, Microsporum canis, Fusarium solani, and Candida glaberata. The results of these studies show the metal(II complexes to be more antibacterial/antifungal against one or more species as compared to the uncomplexed ligands. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties. Five compounds, (3, (7, (10, (11, and (22, displayed potent cytotoxic

  6. Influence of Reactive Transport on the Reduction of U(VI) in the Presence of Fe(III) and Nitrate: Implications for U(VI) Immobilization by Bioremediation / Biobarriers- Final Report

    Energy Technology Data Exchange (ETDEWEB)

    B.D. Wood

    2007-01-01

    Subsurface contamination by metals and radionuclides represent some of the most challenging remediation problems confronting the Department of Energy (DOE) complex. In situ remediation of these contaminants by dissimilatory metal reducing bacteria (DMRB) has been proposed as a potential cost effective remediation strategy. The primary focus of this research is to determine the mechanisms by which the fluxes of electron acceptors, electron donors, and other species can be controlled to maximize the transfer of reductive equivalents to the aqueous and solid phases. The proposed research is unique in the NABIR portfolio in that it focuses on (i) the role of flow and transport in the initiation of biostimulation and the successful sequestration of metals and radionuclides [specifically U(VI)], (ii) the subsequent reductive capacity and stability of the reduced sediments produced by the biostimulation process, and (iii) the potential for altering the growth of biomass in the subsurface by the addition of specific metabolic uncoupling compounds. A scientifically-based understanding of these phenomena are critical to the ability to design successful bioremediation schemes. The laboratory research will employ Shewanella putrefaciens (CN32), a facultative DMRB that can use Fe(III) oxides as a terminal electron acceptor. Sediment-packed columns will be inoculated with this organism, and the reduction of U(VI) by the DMRB will be stimulated by the addition of a carbon and energy source in the presence of Fe(III). Separate column experiments will be conducted to independently examine: (1) the importance of the abiotic reduction of U(VI) by biogenic Fe(II); (2) the influence of the transport process on Fe(III) reduction and U(VI) immobilization, with emphasis on methods for controlling the fluxes of aqueous species to maximize uranium reduction; (3) the reductive capacity of biologically-reduced sediments (with respect to re-oxidation by convective fluxes of O2 and NO3-) and

  7. SERS and DFT investigation of 1-(2-pyridylazo)-2-naphthol and its metal complexes with Al(III), Mn(II), Fe(III), Cu(II), Zn(II) and Pb(II)

    Science.gov (United States)

    Szabó, László; Herman, Krisztian; Mircescu, Nicoleta E.; Fălămaş, Alexandra; Leopold, Loredana F.; Leopold, Nicolae; Buzumurgă, Claudia; Chiş, Vasile

    The development of surface-enhanced Raman scattering (SERS) as a prospective analytical methodology for detection of metal ions was shown in recent years by several studies on metal complexes. In this work, 1-(2-pyridylazo)-2-naphthol (PAN) and its Al(III), Mn(II), Fe(III), Cu(II), Zn(II) and Pb(II) complexes were studied by FTIR, FT-Raman and surface enhanced Raman spectroscopies. Molecular geometry optimization, molecular electrostatic potential (MEP) distribution and vibrational frequencies calculations were performed using the hybrid B3LYP exchange-correlation functional for the PAN molecule and its bidentate complexes. The calculated MEP distributions indicated the atoms with highest electronegativity, the adsorption to the silver surface occurring through these atoms. Based on experimental and theoretical data we were able to identify unique and representative features, useful for the identification of each PAN-metal complex.

  8. The use of a polymer inclusion membrane in flow injection analysis for the on-line separation and determination of zinc.

    Science.gov (United States)

    Zhang, Lujia L; Cattrall, Robert W; Kolev, Spas D

    2011-06-15

    This paper reports the first use of a polymer inclusion membrane (PIM) for on-line separation in flow injection analysis (FIA) involving simultaneous extraction and back-extraction. The FIA system containing the PIM separation module was used for the determination of Zn(II) in aqueous samples in the presence of Mg(II), Ca(II), Cd(II), Co(II), Ni(II), Cu(II), and Fe(III). The Fe(III) and Cu(II) interferences were eliminated by off-line precipitation with phosphate and on-line complexation with chloride, respectively. The concentration of Zn(II) was determined spectrophotometrically using 4-(2-pyridylazo) resorcinol (PAR). The optimal composition of the PIM consisted of 40% (m/m) di(2-ethlyhexyl) phosphoric acid (D2EHPA) as carrier, 10% (m/m) dioctyl phthalate (DOP) as plasticizer and 50% (m/m) poly(vinyl chloride) (PVC) as the base polymer. The optimized FIA system was characterized by a linear calibration curve in the range from 1.0 to 30.0 mg L(-1) Zn(II), a detection limit of 0.05 mg L(-1) and a relative standard deviation of 3.4% with a sampling rate of 4h(-1). Reproducible results were obtained for 20 replicate injections over a 5h period which demonstrated a good membrane stability. The FIA system was applied to the determination of Zn(II) in pharmaceuticals and samples from the galvanizing industry and very good agreement with atomic absorption spectrometry was obtained.

  9. Determinação espectrofotométrica indireta de capsaicinoides em pimentas Capsicum a partir da reação com o complexo de Co(II com 4-(2-piridilazo resorcinol

    Directory of Open Access Journals (Sweden)

    Patrícia Tonon de Souza

    2014-01-01

    Full Text Available Capsaicinoids (CAPS are substances responsible for pungency in Capsicum. It is important to quantify these types of compounds owing to their broad application in food, pharmaceuticals, cosmetics and chemical weapons. In this work, we developed an indirect spectrophotometric method based on the colorimetric reaction between CAPS, Co(II 3.10×10-5 mol L-1 and 4-(2-pyridylazo resorcinol (PAR 6.23×10-5 and, in cachaça:water 92:8v/v solutions, for quantification of total CAPS in Capsicum peppers. The product of the reaction is CoPAR2CAPS2 and its absorption in aquo-ethanolic solution at 510 nm is proportional to the total CAPS concentration from 0.60 to 17.94 mg L-1. The values of limit of detection and limit of quantification were 0.0004 and 0.001 mg of CAPS/g of pepper, respectively, with 4% relative standard deviation. The developed method yielded similar results to those obtained from high performance liquid chromatography, with 95% of confidence.

  10. Synthesis and spectral characterization of Schiff base complexes of Cu(II), Co(II), Zn(II) and VO(IV) containing 4-(4-aminophenyl)morpholine derivatives: antimicrobial evaluation and anticancer studies.

    Science.gov (United States)

    Dhahagani, K; Mathan Kumar, S; Chakkaravarthi, G; Anitha, K; Rajesh, J; Ramu, A; Rajagopal, G

    2014-01-03

    Metal(II) chelates of Schiff bases derived from the condensation of 4-morpholinoaniline with substituted salicylaldehyde have been prepared and characterized by (1)H NMR, IR, electronic, EPR, and magnetic measurement studies. The complexes are of the type M(X-MPMP)2 [where M=Cu(II), Co(II)), Zn(II), or VO(IV); MPMP=2-[(4 morpholinophenyl imino) methyl] 4-X-phenol, X=Cl, (L1H), X=Br (L2H)]. Single crystal X-ray crystallography studies confirm the structure of newly synthesized Schiff bases. The Schiff bases act as bidentate monobasic ligands, coordinating through deprotonated phenolic oxygen and azomethine nitrogen atoms. The free ligands and metal complexes are screened for their biopotency. Metal complexes exhibit better activity than ligands. Anticancer activity of ligands and their metal complexes are evaluated in human heptocarcinoma(HepG2) cells. The preliminary bioassay indicates that the Schiff base and its zinc complex exhibit inhibitory activity against the human gastric cancer cell lines.

  11. Sulphate radical generation through interaction of peroxymonosulphate with Co(II) for in-line sample preparation aiming at spectrophotometric flow-based determination of phosphate and phosphite in fertilizers.

    Science.gov (United States)

    Crispino, Carla C; Kamogawa, Marcos Y; Ferreira, José R; Zagatto, Elias A G

    2016-09-01

    An advanced oxidative process relying on the interaction of peroxymonosulphate and cobalt(II) was implemented for generating the sulphate radicals in flow analysis, in order to accomplish in-line sample preparation thus improving the spectrophotometric determination of phosphate and phosphite in liquid foliar fertilizers. To this end, a flow-batch system with a heated chamber was designed. The sample was handled twice, with and without the step of phosphite oxidation to phosphate, and the formed orthophosphate was quantified after interaction with the vanadate-molybdate reagent. Phosphite was determined as the difference in analytical signals corresponding to sample handling with and without the oxidation step. Influence of Co(II) on the peroxymonosulphate activation, reagent concentrations and added volumes, acidity, temperature and heating time were investigated like aiming at to improve analytical recovery and measurement repeatability, as well as the and system ruggedness. The 6.6-20.0mgL(-1) P2O5 standards were in-line prepared from a single stock solution. Detection limits were estimated as 0.8 and 0.1mgL(-1) for P2O5 and P-PO4. Twenty-four samples are were run per hour, and results are were in agreement with those obtained by the official procedure.

  12. Synthesis, characterization, and antioxidant/cytotoxic activity of new chromone Schiff base nano-complexes of Zn(II), Cu(II), Ni(II) and Co(II)

    Science.gov (United States)

    Saif, M.; El-Shafiy, Hoda F.; Mashaly, Mahmoud M.; Eid, Mohamed F.; Nabeel, A. I.; Fouad, R.

    2016-08-01

    A chromone Schiff base complexes of Zn(II) (1), Cu(II) (2), Ni(II) (3) and Co(II) (4) were successfully prepared in nano domain with crystalline or amorphous structures. The spectroscopic data revealed that the Schiff base ligand behaves as a monoanionic tridentate ligand. The metal complexes exhibited octahedral geometry. Transmission electron microscope (TEM) analysis showed that Cu(II) complex have aggregated nanospheres morphology. The obtained nano-complexes were tested as antioxidant and antitumor agents. The H2L and its Cu(II) complex (2) were found to be more potent antioxidant (IC50(H2L) = 0.93 μM; IC50(Cu(II) complex) = 1.1 μM than standard ascorbic acid (IC50 = 2.1 μM) as evaluated by DPPH• method. The H2L and its complexes (1-4) were tested for their in vitro cytotoxicity against Ehrlich Ascites Carcinoma cell line (EAC). The Cu(II) nano-complex (2) effectively inhibited EAC growth with IC50 value of 47 μM in comparison with its parent compound and other prepared complexes. The high antioxidant activity and antitumor activity of Cu(II) nano-complex (2) were attributed to their chemical structure, Cu(II) reducing capacity, and nanosize property. The toxicity test on mice showed that Zn(II) (1) and Cu(II) (2) nano-complex have lower toxicity than the standard cis-platin.

  13. Synthesis and characterization of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based azo-linked Schiff base ligand

    Science.gov (United States)

    Anitha, C.; Sheela, C. D.; Tharmaraj, P.; Johnson Raja, S.

    2012-12-01

    Azo-Schiff-base complexes of VO(II), Co(II), Ni(II), Cu(II) and Zn(II) have been synthesized and characterized by elemental analysis, IR, UV-Vis, 1H NMR, mass spectra, molar conductance, magnetic susceptibility measurement, electron spin resonance (EPR), CV, fluorescence, NLO and SEM. The conductance data indicate the nonelectrolytic nature of the complexes, except VO(II) complex which is electrolytic in nature. On the basis of electronic spectra and magnetic susceptibility octahedral geometry has been proposed for the complexes. The EPR spectra of copper and oxovanadium complexes in DMSO at 300 and 77 K were recorded and its salient features are reported. The redox behavior of the copper(II) complex was studied using cyclic voltammetry. The in vitro antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella enterica typhi, Bacillus subtilis and Candida strains was studied and compared with that of free ligand by well-diffusion technique. The azo Schiff base exhibited fluorescence properties originating from intraligand (π-π∗) transitions and metal-mediated enhancement is observed on complexation and so the synthesized complexes can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. On the basis of the optimized structures, the second-order nonlinear optical properties (NLO) are calculated by using second-harmonic generation (SHG) and also the surface morphology of the complexes was studied by SEM.

  14. Biodegradable coordination polymer: Polycondensation of glutaraldehyde and starch in complex formation with transition metals Mn(II, Co(II, Ni(II, Cu(II and Zn(II

    Directory of Open Access Journals (Sweden)

    Nahid Nishat

    2016-11-01

    Full Text Available Starch a biopolymer, possesses many unique characteristics features accompanied with some shortcoming simultaneously. Some synthetic compounds are of great help to these demerits of starch and so by an addition of all these alternatively may acquire the tailor made features of starch-based compounds. By combining the individual advantages of starch and some other compounds and elements, starch-based biodegradable polymers were prepared for potential applications in biomedical and environmental fields. In this research, the structural analysis and characterization studies of starch glutaraldehyde polycondensed polymer were undertaken, and then the formation of polymer metal complexes with transition metal in coordinated form are carried out. FT-IR spectroscopy and 1H NMR and 13C NMR spectroscopy were used to analyze the functionality of the synthesized compound. CHN of the synthesized compound was supported by FT-IR and NMR which again proved helpful for structural analysis. Electronic spectroscopy confirmed the geometry of the synthesized compounds. Thermal studies were carried out by thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. Besides this the biodegradable studies were carried out by ASTM standards of biodegradable materials by CO2 evolution in respirometric titration method. All the polymers showed good thermal strength and reduced biodegradation on attachment of transition metals, Mn(II, Co(II, Ni(II, Cu(II and Zn(II.

  15. Synthesis, Spectroscopic Characterization, and In Vitro Antimicrobial Studies of Pyridine-2-Carboxylic Acid N′-(4-Chloro-Benzoyl-Hydrazide and Its Co(II, Ni(II, and Cu(II Complexes

    Directory of Open Access Journals (Sweden)

    Jagvir Singh

    2012-01-01

    Full Text Available N-substituted pyridine hydrazide (pyridine-2-carbonyl chloride and 4-chloro-benzoic acid hydrazide undergoes hydrazide formation of the iminic carbon nitrogen double bond through its reaction with cobalt(II, nickel(II, and copper(II metal salts in ethanol which are reported and characterized based on elemental analyses, IR, solid reflectance, magnetic moment, molar conductance, and thermal analysis (TG. From the elemental analyses data, 1 : 2 metal complexes are formed having the general formulae [MCl2(HL2] · yH2O (where M = Co(II, Ni(II, and Cu(II, y = 1–3. The important infrared (IR spectral bands corresponding to the active groups in the ligand and the solid complexes under investigation were studied. IR spectra show that ligand is coordinated to the metal ions in a neutral bidentate manner with ON donor sites. The solid complexes have been synthesized and studied by thermogravimetric analysis. All the metal chelates are found to be nonelectrolytes. From the magnetic and solid reflectance spectra, the complexes (cobalt(II, nickel(II, and copper(II have octahedral and square planner geometry, respectively. The antibacterial and antifungal activity’s data show that the metal complexes have a promising biological activity comparable with the parent ligand against bacterial and fungal species.

  16. Spectral, structural elucidation and coordination abilities of Co(II) and Mn(II) coordination entities of 2,6,11,15-tetraoxa-9,17-diaza-1,7,10,16-(1,2)-tetrabenzenacyclooctadecaphan-8,17-diene.

    Science.gov (United States)

    Rajiv, Kumar; Rajni, Johar

    2011-09-01

    Designing tactics were tailored and followed by synthetic and formulation methodologies to prepare 2,6,11,15-tetraoxa-9,17-diaza-1,7,10,16-(1,2)-tetrabenzenacyclooctadecaphan-8,17-diene. Spectral techniques (MS, infrared, 1H NMR, 13C NMR, electronic and EPR), physiochemical measurements (elemental analysis, molar conductance and magnetic susceptibility), electrochemistry (cyclic voltammetry) and classical mechanics (molecular modeling) were employed for structural elucidation of Co(II) and Mn(II) coordination entities having N2O4 chromophore. Comparative spectral analysis revealed legating nature of N2O4 donor macrocycle and confirmed host/guest connectivity between ligand and metal(s). Mass spectrometry (MS) determined 1:1 stoichiometry in CEs. Further electrochemical study confirmed change in oxidation and reduction patterns of CEs. Inhibiting potential (antifungal screened against Aspergillus flavus) showed enhanced antimicrobial properties of CEs as compared to ligand. Molecular modeling was employed to find out different molecular features along with their stabilization energies.

  17. Physico-chemical and biological studies of Cu(II, Co(II and Ni(II complexes of an N4 coordinating ligand derived from diacetylbisethylenediamine and benzoic acid

    Directory of Open Access Journals (Sweden)

    Singh Pal Netra

    2012-01-01

    Full Text Available Mononuclear metal complexes of the type [ML1]Cl2 (where, M = = Cu(II, Co(II or Ni(II and L1 = ligand were synthesized by the reaction of a new N4 coordinating ligand, derived from diacetylbisethylenediamine with benzoic acid, and the corresponding hydrated metal chloride salts. The metal complexes were characterized by elemental analysis, melting point determination, molar conductance and magnetic moment measurements, IR, UV-Vis, 1H- and 13C-NMR, and ESR spectroscopy. The ligand and all the metal complexes were stable in the solid state at room temperature. From the analytical and spectroscopic investigations, the stoichiometry of the complexes was found to be 1:1 (metal:ligand. Based on the electronic spectra and magnetic moment data, the metal complexes had a square planar geometry. The molar conductance values show the 1:2 electrolytic nature of the metal complexes. A cyclic voltammetric study of the Cu(II metal complex has also performed, which showed one electron quasi-reversible reduction around -0.92 to -1.10 V. In vitro biological activities of the ligand and metal complexes was checked against two bacteria Bacillus subtilis and Escherichia coli and two fungi Aspirgillus niger and A. flavus which showed the antibacterial and antifungal properties of the ligand and its metal complexes.

  18. Synthesis, characterization, thermal study and biological evaluation of Cu(II), Co(II), Ni(II) and Zn(II) complexes of Schiff base ligand containing thiazole moiety

    Science.gov (United States)

    Nagesh, G. Y.; Mahendra Raj, K.; Mruthyunjayaswamy, B. H. M.

    2015-01-01

    The novel Schiff base ligand 2-(4-(dimethylamino)benzylidene)-N-(4-phenylthiazol-2-yl)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 4-dimethylaminobenzaldehyde and its newly synthesized Cu(II), Co(II), Ni(II) and Zn(II) complexes have been characterized by microanalysis, magnetic susceptibility, molar conductance, thermal analysis, FT-IR, 1H NMR, ESI mass, UV-Visible, ESR spectroscopy and powder X-ray diffraction data. The newly synthesized ligand behaves as a bidentate ON donor. The IR results confirmed the bidentate binding of the ligand involving oxygen atom of amide carbonyl and azomethine nitrogen. 1H NMR spectral data of the ligand (L) and its Zn(II) complex agreed well with the proposed structures. In order to evaluate the effect of antimicrobial activity of metal ions upon chelation, the newly synthesized ligand and its metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage activities were studied using plasmid DNA pBR322 as a target molecule by agarose gel electrophoresis method. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties of all the compounds against Artemia salina. Furthermore, the antioxidant activity of the ligand (L) and its metal complexes were determined in vitro by reduction of 1,1-diphenyl-2-picryl hydrazyl (DPPH), the ligand exhibited potent in vitro - antioxidant activity than its metal complexes.

  19. Synthesis, structural, spectral (FT-IR, FT-Ra, and UV-Vis), thermal, and density functional studies on p-methylaniline complexes of Mn(II), Co(II), and Ni(II) bromides

    Science.gov (United States)

    Bardakçı, Tayyibe; Altun, Ahmet; Golcuk, Kurtulus; Kumru, Mustafa

    2015-11-01

    Transition metal complexes of the form MBr2L2, where M = Mn(II), Co(II) and Ni(II); L = p-methylaniline, were prepared and characterized by elemental and thermogravimetric analyses, magnetic moment measurements, and UV-vis, FT-IR and FT-Raman spectral studies. Geometries, spin-state energetics, and vibrational spectra of the complexes were obtained at the B3LYP/def2-TZVP level. The present experimental and theoretical data suggest 5-coordinate polymeric bromide bridged structure for the Mn complex, distorted tetrahedral structure for the Co complex, and distorted octahedral coordination site for the Ni complex. The experimental FT-IR and FT-Raman bands of the complexes were assigned based on the computational results expressed in terms of internal coordinates with percent potential energy distributions. The vibrational spectra suggest that the coordination occurs via nitrogen atom of p-methylaniline. The thermal characteristics of the complexes indicate that their decompositions start through p-methylaniline.

  20. Spectrophotometric, conductometric and thermal studies of Co(II), Ni(II) and Cu(II) complexes with 2-(2-hydroxynaphthylazo)-4-hydroxy-6-methyl-1,3-pyrimidine

    Science.gov (United States)

    Gaber, Mohamed; Mansour, Ikhlas A.; El-Sayed, Yousif S. Y.

    2007-10-01

    The electronic absorption spectra of 2-(2-hydroxynaphthylazo)-4-hydroxy-6-methyl-1,3-pyrimidine in pure organic solvents of different polarities and in buffer solutions of varying pH are studied. The important bands in the IR and the main signals in the 1H NMR spectra are assigned. The observed UV-vis absorption bands are assigned to the corresponding electronic transitions. The molecular stoichiometry, stability constant, absorption maximum, molar absorptivity and Sandell's sensitivity of the complexes are calculated. Obeyence to Beer's law and Ringbom optimum concentration ranges are also determined. The ability of using the titled azodye as metalochromic indicator in complexometric titrations was also studied. The effect of Co(II), Ni(II) and Cu(II) ions on the fluorescence of the azodye is also considered. The solid Cu(II) complexes of the titled azodye have been prepared and characterized by elemental, IR, UV-vis spectra as well as by conductometric and magnetic measurements. The data suggest square planar geometry for 1:1 and 1:2 (M:L) complexes. The thermal behaviour of the complexes has been studied. The kinetic parameters ( n, E, A, Δ H, Δ S and Δ G) of the thermal decomposition steps are computed using Coats-Redfern equations.

  1. Reversible thermally induced phase transition in ordered domains of Co(II)-5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)-porphyrin on Cu(111)

    Science.gov (United States)

    Stark, Michael; Ditze, Stefanie; Thomann, Michael; Lungerich, Dominik; Jux, Norbert; Steinrück, Hans-Peter; Marbach, Hubertus

    2016-08-01

    We investigated the adsorption behavior of Co(II)-5,10,15,20-tetrakis-(3,5-di-tert-butylphenyl)-porphyrin (CoTTBPP) on Cu(111) by scanning tunneling microscopy (STM). At room temperature (RT), the coverage dependent adsorption behavior follows an expected scheme: at low coverage step decoration is found, which evolves into supramolecular domains with a hexagonal order at higher coverage. Interestingly, upon cooling the sample to 180 K the occurrence of a clearly distinguishable coexisting herringbone phase is observed. Upon heating to RT again, the herringbone phase vanishes. Thus a temperature dependent, fully reversible phase transition was observed. High resolution STM micrographs allow for the determination of the intramolecular conformations which are different for the two supramolecular arrangements. In addition, we studied the bias voltage dependent appearance of the molecule in STM and assigned a dominant contribution of the central Co at negative bias voltages close to the Fermi edge to the occupied dz2 orbital. Interestingly, the herringbone phase, which dominates at 180 K, exhibits a significantly higher molecular density than the monomodal hexagonal arrangement at RT, which is in line with the "normal" behavior of freezing substances.

  2. N-((5-chloropyridin-2-yl)carbamothioyl)furan-2-carboxamide and its Co(II), Ni(II) and Cu(II) complexes: Synthesis, characterization, DFT computations, thermal decomposition, antioxidant and antitumor activity

    Science.gov (United States)

    Yeşilkaynak, Tuncay; Özpınar, Celal; Emen, Fatih Mehmet; Ateş, Burhan; Kaya, Kerem

    2017-02-01

    N-((5-chloropyridin-2-yl)carbamothioyl)furan-2-carboxamide (HL: C11H8ClN3O2S) and its Co(II), Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analysis, FT-IR,1H NMR and HR-MS methods. The HL was characterized by single crystal X-ray diffraction technique. It crystallizes in the monoclinic system. The HL has the space group P 1 21/c 1, Z = 4, and its unit cell parameters are a = 4.5437(5) Å, b = 22.4550(3) Å, c = 11.8947(14) Å. The ligand coordinates the metal ions as bidentate and thus essentially yields neutral complexes of the [ML2] type. ML2 complex structures were optimized using B97D/TZVP level. Molecular orbitals of both HL ligand were calculated at the same level. Thermal decomposition of the complexes has been investigated by thermogravimetry. The complexes were screened for their anticancer and antioxidant activities. Antioxidant activity of the complexes was determined by using the DPPH and ABTS assays. The anticancer activity of the complexes was studied by using MTT assay in MCF-7 breast cancer cells.

  3. Synthesis, characterization, computational studies, antimicrobial activities and carbonic anhydrase inhibitor effects of 2-hydroxy acetophenone-N-methyl p-toluenesulfonylhydrazone and its Co(II), Pd(II), Pt(II) complexes

    Science.gov (United States)

    Özbek, Neslihan; Alyar, Saliha; Memmi, Burcu Koçak; Gündüzalp, Ayla Balaban; Bahçeci, Zafer; Alyar, Hamit

    2017-01-01

    2-Hydroxyacetophenone-N-methyl p-toluenesulfonylhydrazone (afptsmh) derived from p-toluenesulfonicacid-1-methylhydrazide (ptsmh) and its Co(II), Pd(II), Pt(II) complexes were synthesized for the first time. Synthesized compounds were characterized by spectroscopic methods (FT-IR, 1Hsbnd 13C NMR, LC-MS, UV-vis), magnetic susceptibility and conductivity measurements. 1H and 13C shielding tensors for crystal structure of ligand were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments were performed at B3LYP/6-311++G(d,p) theory level combined with scaled quantum mechanics force field (SQMFF) methodology. The antibacterial activities of synthesized compounds were studied against some Gram positive and Gram negative bacteria by using microdilution and disc diffusion methods. In vitro enzyme inhibitory effects of the compounds were measured by UV-vis spectrophotometer. The enzyme activities against human carbonic anhydrase II (hCA II) were evaluated as IC50 (the half maximal inhibitory concentration) values. It was found that afptsmh and its metal complexes have inhibitory effects on hCA II isoenzyme. General esterase activities were determined using alpha and beta naphtyl acetate substrates (α- and β-NAs) of Drosophila melanogaster (D. melanogaster). Activity results show that afptsmh does not strongly affect the bacteria strains and also shows poor inhibitory activity against hCAII isoenzyme whereas all complexes posses higher biological activities.

  4. Synthesis, spectroscopic characterization, DNA interaction and biological activities of Mn(II), Co(II), Ni(II) and Cu(II) complexes with [(1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol

    Science.gov (United States)

    Gaber, Mohamed; El-Wakiel, Nadia A.; El-Ghamry, Hoda; Fathalla, Shaimaa K.

    2014-11-01

    Manganese(II), cobalt(II), nickel(II) and copper(II) complexes of [(1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol have been synthesized. The structure of complexes have been characterized by elemental analysis, molar conductance, magnetic moment measurements and spectral (IR, 1H NMR, EI-mass, UV-Vis and ESR), and thermal studies. The results showed that the chloro and nitrato Cu(II) complexes have octahedral geometry while Ni(II), Co(II) and Mn(II) complexes in addition to acetato Cu(II) complex have tetrahedral geometry. The possible structures of the metal complexes have been computed using the molecular mechanic calculations using the hyper chem. 8.03 molecular modeling program to confirm the proposed structures. The kinetic and thermodynamic parameters of the thermal decomposition steps were calculated from the TG curves. The binding modes of the complexes with DNA have been investigated by UV-Vis absorption titration. The results showed that the mode of binding of the complexes to DNA is intercalative or non-intercalative binding modes. Schiff base and its metal complexes have been screened for their in vitro antimicrobial activities against Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli and Pesudomonas aeruginosa), fungi (Asperigllus flavus and Mucer) and yeast (Candida albicans and Malassezia furfur).

  5. Synthesis of New VO(II), Co(II), Ni(II) and Cu(II) Complexes with Isatin-3-Chloro-4-Floroaniline and 2-Pyridinecarboxylidene-4-Aminoantipyrine and their Antimicrobial Studies.

    Science.gov (United States)

    Mishra, Anand P; Mishra, Rudra; Jain, Rajendra; Gupta, Santosh

    2012-03-01

    The complexes of tailor made ligands with life essential metal ions may be an emerging area to answer the problems of multi drug resistance. The coordination complexes of VO(II), Co(II), Ni(II) and Cu(II) with the Schiff bases derived from isatin with 3-chloro-4-floroaniline and 2-pyridinecarboxaldehyde with 4-aminoantipyrine have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, FAB mass and magnetic susceptibility measurements. FAB mass data show degradation of complexes. Both the ligands behave as bidentate and tridentate coordinating through O and N donor. The complexes exhibit coordination number 4, 5 or 6. The Schiff base and metal complexes show a good activity against the bacteria; Staphylococcus aureus, Escherichia coli and Streptococcus fecalis and fungi Aspergillus niger, Trichoderma polysporum, Candida albicans and Aspergillus flavus. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases. The minimum inhibitory concentrations of the metal complexes were found in the range 10~40 µg/mL.

  6. Some new nano-sized Fe(II), Cd(II) and Zn(II) Schiff base complexes as precursor for metal oxides: Sonochemical synthesis, characterization, DNA interaction, in vitro antimicrobial and anticancer activities.

    Science.gov (United States)

    Abdel-Rahman, Laila H; Abu-Dief, Ahmed M; El-Khatib, Rafat M; Abdel-Fatah, Shimaa Mahdy

    2016-12-01

    The complexes of Fe(II), Cd(II) and Zn(II) with Schiff base derived from 2-amino-3-hydroxypyridine and 3-methoxysalicylaldehyde have been prepared. Melting points, decomposition temperatures, Elemental analyses, TGA, conductance measurements, infrared (IR) and UV-Visible spectrophotometric studies were utilized in characterizing the compounds. The UV-Visible spectrophotometric analysis revealed 1:1 (metal-ligand) stoichiometry for the three complexes. In addition to, the prepared complexes have been used as precursors for preparing their corresponding metal oxides nanoparticles via thermal decomposition. The structures of the nano-sized complexes and their metal oxides were characterized by X-ray powder diffraction and transmittance electron microscopy. Moreover, the prepared Schiff base ligand, its complexes and their corresponding nano-sized metal oxides have been screened in vitro for their antibacterial activity against three bacteria, gram-positive (Microccus luteus) and gram-negative (Escherichia coli, Serratia marcescence) and three strains of fungus. The metal chelates were shown to possess more antimicrobial activity than the free Schiff-base chelate and their nano-sized metal oxides have the highest activity. The binding behaviors of the complexes to calf thymus DNA have been investigated by absorption spectra, viscosity mensuration and gel electrophoresis. The DNA binding constants reveal that all these complexes interact with DNA through intercalative binding mode. Furthermore, the cytotoxic activity of the prepared Schiff base complexes on human colon carcinoma cells, (HCT-116 cell line) and hepatic cellular carcinoma cells, (HepG-2) showed potent cytotoxicity effect against growth of carcinoma cells compared to the clinically used Vinblastine standard.

  7. Microencapsulated Aliivibrio fischeri in Alginate Microspheres for Monitoring Heavy Metal Toxicity in Environmental Waters

    Directory of Open Access Journals (Sweden)

    Dedi Futra

    2014-12-01

    Full Text Available In this article a luminescence fiber optic biosensor for the microdetection of heavy metal toxicity in waters based on the marine bacterium Aliivibrio fischeri (A. fischeri encapsulated in alginate microspheres is described. Cu(II, Cd(II, Pb(II, Zn(II, Cr(VI, Co(II, Ni(II, Ag(I and Fe(II were selected as sample toxic heavy metal ions for evaluation of the performance of this toxicity microbiosensor. The loss of bioluminescence response from immobilized A. fischeri bacterial cells corresponds to changes in the toxicity levels. The inhibition of the luminescent biosensor response collected at excitation and emission wavelengths of 287 ± 2 nm and 487 ± 2 nm, respectively, was found to be reproducible and repeatable within the relative standard deviation (RSD range of 2.4–5.7% (n = 8. The toxicity biosensor based on alginate micropsheres exhibited a lower limit of detection (LOD for Cu(II (6.40 μg/L, Cd(II (1.56 μg/L, Pb(II (47 μg/L, Ag(I (18 μg/L than Zn(II (320 μg/L, Cr(VI (1,000 μg/L, Co(II (1700 μg/L, Ni(II (2800 μg/L, and Fe(III (3100 μg/L. Such LOD values are lower when compared with other previous reported whole cell toxicity biosensors using agar gel, agarose gel and cellulose membrane biomatrices used for the immobilization of bacterial cells. The A. fischeri bacteria microencapsulated in alginate biopolymer could maintain their metabolic activity for a prolonged period of up to six weeks without any noticeable changes in the bioluminescence response. The bioluminescent biosensor could also be used for the determination of antagonistic toxicity levels for toxicant mixtures. A comparison of the results obtained by atomic absorption spectroscopy (AAS and using the proposed luminescent A. fischeri-based biosensor suggests that the optical toxicity biosensor can be used for quantitative microdetermination of heavy metal toxicity in environmental water samples.

  8. Separation and preconcentration of Cd(II), Cu(II), Ni(II), and Pb(II) in water and food samples using Amberlite XAD-2 functionalized with 3-(2-nitrophenyl)-1H-1,2,4-triazole-5(4H)-thione and determination by inductively coupled plasma-atomic emission spectrometry.

    Science.gov (United States)

    Kumar, Bommana Naresh; Ramana, D K Venkata; Harinath, Yapati; Seshaiah, Kalluru; Wang, M C

    2011-10-26

    A separation and preconcentration procedure was developed for the determination of trace amounts of Cd(II), Cu(II), Ni(II), and Pb(II) in water and food samples using Amberlite XAD-2 fuctionalized with a new chelating ligand, 3-(2-nitrophenyl)-1H-1,2,4-triazole-5(4H)-thione (Amberlite XAD-2-NPTT). The chelating resin was characterized by Fourier transform infrared spectroscopy (FT-IR) and used as a solid sorbent for enrichment of analytes from samples. The sorbed elements were subsequently eluted with 10 mL of 1.0 M HNO(3), and the eluates were analyzed by inductively coupled plasma-atomic emission spectrometry. The influences of the analytical parameters including pH, amount of adsorbent, eluent type and volume, flow rate of the sample solution, volume of the sample solution, and effect of matrix on the preconcentration of metal ions have been studied. The optimum pH for the sorption of four metal ions was about 6.0. The limits of detection were found to be 0.22, 0.18, 0.20, and 0.16 μg L(-1) for Cd(II), Cu(II), Ni(II), and Pb(II), respectively, with a preconcentration factor 60. The proposed method was applied successfully for the determination of metal ions in water and food samples.

  9. Synthesis and characterization of binary and ternary complexes of Co(II), Ni(II), Cu(II) and Zn(II) ions based on 4-aminotoluene-3-sulfonic acid

    Science.gov (United States)

    Faheim, Abeer A.; Abdou, Safaa N.; Abd El-Wahab, Zeinab H.

    2013-03-01

    Salicylidene (4-aminotoluene-3-sulfonic acid) Schiff base ligand H2L, and its binary and ternary Co(II), Ni(II), Cu(II) and Zn(II) complexes using 8-hydroxyquinoline (8-HOqu) and 2-aminopyridine (2-Ampy) as secondary ligands have been synthesised and characterized via elemental analysis, spectral data (IR, 1H NMR, mass and solid reflectance), molar conductance, magnetic moment, TG-DSC measurements and XRPD analysis. Correlation of all spectroscopic data suggest that H2L ligand acts as monoanionic terdentate ligand with ONO sites coordinating to the metal ions via deprotonated phenolic-O, azomethine-N and sulfonate-O while 2-Ampy behaves as a neutral monodentate ligand via amino group-N and 8-HOqu behaves as a monoanionic bidentate ligand through the ring-N and deprotonated phenolic-O. The thermal behavior of these complexes shows that the coordinated water molecules were eliminated from the complexes at relatively higher temperatures than the hydrated water and there are two routes in removal of coordinated water molecules. All complexes have mononuclear structure and the tetrahedral, square planar or an octahedral geometry have been proposed. The ligand and its complexes have been screened for their antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Candida albicans and Aspergillus fumigatus. Among the synthesised compounds, the binary and ternary Ni(II) complexes, (2, 8 and 10) and ternary Zn(II) complex, (12) were found to be very effective against Candida albicans and Bacillus subtilis than all other complexes with MICs of 2 and 8 μg/mL, respectively.

  10. 包埋磷酸盐小球的合成及其对溶液中铅镉的吸附与固定%Synthesis of phosphate-embedded calcium alginate beads for Pb(II) and Cd(II) sorption and immobilization in aqueous solutions

    Institute of Scientific and Technical Information of China (English)

    王云燕; 姚文斌; 王庆伟; 杨志辉; 梁丽芬; 柴立元

    2016-01-01

    采用海藻酸钠、磷酸二氢钙和碳酸氢钠成功合成了包埋磷酸盐的海藻酸钙小球。通过扫描电镜、傅里叶变换红外光谱、X射线衍射等分析表征了该小球的形貌与结构。研究pH值和初始金属离子浓度对铅镉去除率的影响,发现吸附铅镉的最佳pH值分别为4.0和5.5;铅镉的最适初始浓度分别为200 mg/L和25 mg/L,对应的去除率分别达94.2%和80%。XRD和FTIR的分析结果证实了该小球对铅镉的去除机理为:铅镉离子吸附到小球的表面,与小球的羧基发生反应,进而与磷酸根反应生成稳定的磷酸盐沉淀。铅镉的吸附符合Langmuir等温线方程,拟合系数R2分别为0.9957和0.988。根据Langmuir等温线方程计算得到铅镉的理论饱和吸附量分别为263.16 mg/g和82.64 mg/g。研究结果表明该小球对溶液中的铅镉离子有良好的处理效果,同时由于生成稳定的沉淀物,也能应用于处理被铅镉污染的水稻土。%The phosphate-embedded calcium alginate beads were successfully synthesized based on sodium alginate, calcium dihydrogen phosphate and sodium hydrogen carbonate. Scanning electron microscopy, Fourier transformed infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were conducted to characterize the morphology and structure of the phosphate-embedded calcium alginate beads. The effects of pH and the initial concentration of the metal ions on Pb(II) and Cd(II) sorption by the beads were investigated. The optimal pH values for Pb(II) and Cd(II) sorption are 4.0 and 5.5, respectively. The optimal initial concentrations of Pb(II) and Cd(II) are 200 mg/L and 25 mg/L, correspondingly, and the removal efficiencies are 94.2%and 80%, respectively. The sorption mechanism is that the heavy metal ions accessed the beads firstly due to the large surface area, combined with OH−, and then precipitated with phosphate radical, which was proven by FTIR and XRD. The sorption of Pb(II) and Cd(II

  11. Liquid-liquid extraction (LLE) of Fe(III) and Ti(IV) by bis-(2-ethyl-hexyl) phosphoric acid (D2EHPA) in sulfuric acid medium; Extracao liquido-liquido de ferro (III) e titanio (IV) pelo acido bis-(2-etil-hexil) fosforico (D2EHPA) em meio de acido sulfurico

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Glauco Correa da; Cunha, Jose Waldemar Silva Dias da [Instituto de Engenharia Nuclear (IEN), Rio de Janeiro, RJ (Brazil). Dept. de Quimica e Materiais Nucleares; Dweck, Jo [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica. Dept. de Processos Inorganicos; Afonso, Julio Carlos [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica. Dept. de Quimica Analitica]. E-mail: julio@iq.ufrj.br

    2008-07-01

    This work presents a study on the separation of Fe(III) and Ti(IV) from sulfuric acid leaching solutions of ilmenite (FeTiO{sub 3}) using liquid-liquid extraction with D2EHPA in n-dodecane as extracting agent. The distribution coefficients (K{sub D}) of the elements related to free acidity and concentration of Fe(III) and Ti(IV) were determined. Free acidity was changed from 3x10{sup -2} to 11.88 mol L{sup -1} and D2EHPA concentration was fixed at 1.5 mol L{sup 1}. Recovery of final products as well as recycling of wastes generated in the process were also investigated. The LLE process as a feasible alternative to obtain high-purity TiO{sub 2}. (author)

  12. Crystal structure of K0.75[FeII3.75FeIII1.25(HPO36]·0.5H2O, an open-framework iron phosphite with mixed-valent FeII/FeIII ions

    Directory of Open Access Journals (Sweden)

    Edurne S. Larrea

    2016-01-01

    Full Text Available Single crystals of the title compound, potassium hexaphosphitopentaferrate(II,III hemihydrate, K0.75[FeII3.75FeIII1.25(HPO36]·0.5H2O, were grown under mild hydrothermal conditions. The crystal structure is isotypic with Li1.43[FeII4.43FeIII0.57(HPO36]·1.5H2O and (NH42[FeII5(HPO36] and exhibits a [FeII3.75FeIII1.25(HPO36]0.75− open framework with disordered K+ (occupancy 3/4 as counter-cations. The anionic framework is based on (001 sheets of two [FeO6] octahedra (one with point group symmetry 3.. and one with point group symmetry .2. linked along [001] through [HPO3]2− oxoanions. Each sheet is constructed from 12-membered rings of edge-sharing [FeO6] octahedra, giving rise to channels with a radius of ca 3.1 Å where the K+ cations and likewise disordered water molecules (occupancy 1/4 are located. O...O contacts between the water molecule and framework O atoms of 2.864 (5 Å indicate hydrogen-bonding interactions of medium strength. The infrared spectrum of the compound shows vibrational bands typical for phosphite and water groups. The Mössbauer spectrum is in accordance with the presence of FeII and FeIII ions.

  13. Changes in physiological activity of algae Desmodesmus quadricauda after active bioaccumulation of newly prepared and characterized Fe(III) complexes with pyridine-3-carboxamide (pca) by living algal cells.

    Science.gov (United States)

    Fargasová, Agáta; Ondrejkovicová, Iveta; Kramarová, Zuzana; Fáberová, Zuzana

    2010-08-01

    The study characterized five iron(III) complexes with heterocyclic N-donor ligand pyridine-3-carboxamide (pca) [FeCl(3)(pca)(3)], [Fe(H(2)O)(2)(pca)(3)](ClO(4))(3), [Fe(2)O(ac)(2)(pca)(6)]Cl(2).3H(2)O, [Fe(NO(3))(3)(pca)(3)].3H(2)O, [Fe(Cl(2)ac)(3)(pca)(3)] (ac=acetate, Cl(2)ac=dichloroacetate) and their effects on biomass, chlorophylls (a, b), photosynthetic oxygen production and iron biosorption in algae Desmodesmus quadricauda. The effects of Fe(III) complexes were compared with control and those of FeCl(3).6H(2)O. While pca coordination to iron atom through the nitrogen atom of its heterocyclic ring mostly increased iron inhibitory effect on algal biomass and chlorophylls production, oxygen production was enhanced. The exceptions were observed only for [Fe(2)O(ac)(2)(pca)(6)]Cl(2).3H(2)O complex effect on biomass and oxygen production and [Fe(H(2)O)(2)(pca)(3)](ClO(4))(3) complex effect on chlorophylls production. Complexation increased iron biosorption in algal biomass and iron accumulated amount in algae was 2.8-20 times higher than that from FeCl(3).6H(2)O with maximal accumulation from dimeric complex [Fe(2)O(ac)(2)(pca)(6)]Cl(2).3H(2)O.

  14. Comparative ligational, optical band gap and biological studies on Cr(III) and Fe(III) complexes of hydrazones derived from 2-hydrazinyl-2-oxo-N-phenylacetamide with both vanillin and O-vanillin

    Science.gov (United States)

    Yousef, T. A.; Abu El-Reash, G. M.; Attia, M. I.; El-Tabai, M. N.

    2015-09-01

    The Cr(III) and Fe(III) complexes of hydrazones derived from the condensation of 2-hydrazinyl-2-oxo-N-phenylacetamide with both vanillin and o-vanillin synthesized and characterized by different conventional physicochemical techniques. The kinetic and thermodynamic parameters for the different decomposition steps were calculated using Coats-Redfern and Horowitz-Metzger equations. The bond lengths, bond angles, HOMO, LUMO, dipole moment and binding energy calculated by DFT calculations. The optical band gap (Eg) values equal 3.28, 3.03, 3.58 and 3.57 eV for [Cr(HL1)Cl2(H2O)2](0.75H2O), [Cr(HL2)Cl2(H2O)](H2O), [Fe(HL1)Cl2(H2O)2](0.5H2O) and [Fe(HL2)2Cl(H2O)](3H2O) complexes, respectively. The antibacterial activities tested against Bacillus subtilis and Escherichia coli bacteria.

  15. Structural, magnetic and optical properties of an Fe(III) dimer bridged by the meridional planar divergent N,N'-bis(salicyl)hydrazide and its photo- and electro-chemistry in solution.

    Science.gov (United States)

    Cheaib, Khaled; Martel, David; Clément, Nicolas; Eckes, Fabrice; Kouaho, Stéphanie; Rogez, Guillaume; Dagorne, Samuel; Kurmoo, Mohamedally; Choua, Sylvie; Welter, Richard

    2013-02-07

    {Fe(III)Cl(DMF)(2)}(2)(L) where L is N,N'-bis(salicyl)hydrazide has been synthesized as red crystals and characterized using single-crystal diffraction, infrared and UV-vis spectroscopies, and its magnetic properties studied. The dimeric unit in the structure is formed through the two meridional sets of divergent O, N, O coordinating atoms of the hexacoordinated and quadruply charged ligand. With the presence of the inversion symmetry the Fe atoms are strictly planar with the ligand. The magnetic exchange interaction is found to be antiferromagnetic with a J = -5.98(3) cm(-1) through the rare Fe-N-N-Fe pathway. Irradiation of the FeCl(3)/H(4)L red DMF solution in the visible region of the spectrum resulted in its complete discoloration and from which the unknown colorless salt [Fe(II)(DMF)(6)][Fe(II)Cl(4)] and the neutral ligand have been identified by single crystal diffraction. The UV-visible spectra of FeCl(3), H(4)L and their mixture in DMF solution indicate that the iron complex is the absorbing species and the presence of the free ligand in the irradiated solution suggests that the ligand is potentially acting as a catalyst to the photoreduction of Fe(III) to Fe(II), while electrochemistry points to a mixed-valent (Fe(II)-Fe(III)) intermediate in the process.

  16. An experimental design to optimize the flow extraction parameters for the selective removal of Fe(III) and Al(III) in aqueous samples using salicylic acid grafted on Amberlite XAD-4 and final determination by GF-AAS.

    Science.gov (United States)

    Vanloot, P; Boudenne, J-L; Brach-Papa, C; Sergent, M; Coulomb, B

    2007-08-17

    In this paper, a multivariable approach has been applied for the selective removing of Fe(III) and Al(III), in the range 0-200 microg l(-1), in water samples onto a modified organic support (salicylic acid grafted on XAD-4). An empirical mathematical model was designed which establishes the relationship between the variation of the responses (extraction yields), and the variation of three factors (sample volume, sample percolation flow rate and amount of metallic ions present in the sample). To estimate the coefficients of the developed model, an uniform shell Doehlert design has been applied; these experiments consisted in GF-AAS determination of aluminium and iron amounts in eluates after percolation of samples through modified support. Results show a similar behaviour of the resin towards aluminium and iron with a preponderant effect of the percolation flow rate value; however this one is crucial for aluminium extraction and should be maintained below to 0.55 ml min(-1) to reach a 95% Al3+ extraction yield (versus 2.25 ml min(-1) for Fe3+). The optima determined by this experimental design approach have been further applied to the selective extraction of aluminium and iron from multielement synthetic samples and from real samples at the outlet of potable water treatment units.

  17. Hydrothermal Synthesis and Properties of Open-Framework Mixed-valence Iron Phosphates FeIII2FeII1.5(PO4)3 with Three-dimensional Structure

    Institute of Scientific and Technical Information of China (English)

    DUAN,Li-Ying(段丽颖); LIU,Fu-Chen(刘福臣); WANG,En-Bo(王恩波); LI,Yang-Guang(李阳光); HU,Chang-Wen(胡长文); XU,Lin(许林)

    2004-01-01

    The open-framework iron phosphate FeIII2FeII1.5(PO4)3 was hydrothermally synthesized and characterized by elemental analysis, IR, EPR, XPS and single crystal X-ray diffraction analysis. The title compound crystallized in the triclinic, space group P1 with a=0.64724(4) nm, b=0.79651(6) nm, c=0.94229(5) nm, α=104.447(2)°, β=108.919(4)°, γ=101.741(4)°, V=0.42302(5) nm3, Z=1 and R1 (wR2)=0.0307 (0.0793). Crystal data were collected on a Rigaku R-AXIS RAPID IP diffractometer with Mo Kα (λ=0.071073 nm) at 293(2) K in the range of 2.43°<θ<27.46°. The structure of 1 consists of 19 non-hydrogen atoms including three and a half crystallographically independent Fe and three P atoms. Fe(1) connects its symmetrical Fe(1A) through bridging oxygen forming a dimer and the dimers are connected by Fe(4) forming an infinite staircase-like chain. Fe(2) and Fe(3) connect the infinite chains into a layer with bridging oxygen. Layers are interconnected via Fe(4) forming the six-membered and eight-membered channel systems.

  18. Design, spectral characterization, thermal, DFT studies and anticancer cell line activities of Co(II), Ni(II) and Cu(II) complexes of Schiff bases derived from 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol.

    Science.gov (United States)

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B S; Yadav, Deepak

    2015-06-15

    A series of two biologically active Schiff base ligands L(1), L(2) have been synthesized in equimolar reaction of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol with thiophene-2-carbaldehyde and furan-2-carbaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 1:1 and 2:1. The characterization of Schiff bases and metal complexes was done by (1)H NMR, UV-Vis, TGA, IR, mass spectrometry and molar conductivity studies. The in DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II), Ni(II) and Cu(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2) were studied and compared with those of free ligand. The anticancer cell line results reveal that all metal complexes show moderate to significant % cytotoxicity on cell line HepG2 and MCF-7.

  19. Design, spectral characterization, thermal, DFT studies and anticancer cell line activities of Co(II), Ni(II) and Cu(II) complexes of Schiff bases derived from 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol

    Science.gov (United States)

    Tyagi, Prateek; Chandra, Sulekh; Saraswat, B. S.; Yadav, Deepak

    2015-06-01

    A series of two biologically active Schiff base ligands L1, L2 have been synthesized in equimolar reaction of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol with thiophene-2-carbaldehyde and furan-2-carbaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 1:1 and 2:1. The characterization of Schiff bases and metal complexes was done by 1H NMR, UV-Vis, TGA, IR, mass spectrometry and molar conductivity studies. The in DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II), Ni(II) and Cu(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2) were studied and compared with those of free ligand. The anticancer cell line results reveal that all metal complexes show moderate to significant % cytotoxicity on cell line HepG2 and MCF-7.

  20. Determination of Cd(II, Zn(II and Ag(Iin different matrixes after solid phase extraction on sodium dodecyl sulfate(SDS-coated alumina as their 2,3 Di Hydro 2,3 paratolylQinazoline (1 H- 4 one (DPTQO by Flame atomic absorption spectrometric

    Directory of Open Access Journals (Sweden)

    Farveh Raoufi

    2016-03-01

    Full Text Available A sensitive and selective solid phase extraction procedure for the determination of traces of Cd(II, Zn(II and Ag(I ions has been developed. An alumina-sodium dodecyl sulfate (SDS coated on with 2,3 Di Hydro 2,3 paratolylQinazoline (1 H- 4 one (DPTQO. The influences of the analytical parameters including pH and sample volume were investigated.Common coexisting ions did not interfere on the separation and determination of analytes under study. The adsorbed analytes were desorbed by using 6mL of 4 mol L−1 nitric acid. The responses are linear 0.02–0.85 µg mL-1 for Cd2+ ion0.01–0.90 µg mL-1 for Zn2+and0.02–0.92µg mL-1for Ag+ detection limit for Cd(II, Zn(II and Ag(I ions were found to be 1.4, 1.3 and1.12(ng mL-1, respectively.It was found that the recovery for Cd2+, Zn2+and Ag+ ions were 97.7, 98.2 and 98.0 with RSD of 1.9, 1.8 and 1.7. It was also observed that recovery for repeated recovery on the same solid phase not varies more than 3%. The presented procedurewas successfully applied for determination of analytes in radiology wastewater, amalgam, natural water and blood samples.

  1. Selective Iron(III ion uptake using CuO-TiO2 nanostructure by inductively coupled plasma-optical emission spectrometry

    Directory of Open Access Journals (Sweden)

    Rahman Mohammed M

    2012-12-01

    Full Text Available Abstract Background CuO-TiO2 nanosheets (NSs, a kind of nanomaterials is one of the most attracting class of transition doped semiconductor materials due to its interesting and important optical, electrical, and structural properties and has many technical applications, such as in metal ions detection, photocatalysis, Chemi-sensors, bio-sensors, solar cells and so on. In this paper the synthesis of CuO-TiO2 nanosheets by the wet-chemically technique is reported. Methods CuO-TiO2 NSs were prepared by a wet-chemical process using reducing agents in alkaline medium and characterized by UV/vis., FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS, powder X-ray diffraction (XRD, and field-emission scanning electron microscopy (FE-SEM etc. Results The structural and optical evaluation of synthesized NSs were measured by XRD pattern, Fourier transform infrared (FT-IR and UV–vis spectroscopy, respectively which confirmed that the obtained NSs are well-crystalline CuO-TiO2 and possessing good optical properties. The morphological analysis of CuO-TiO2 NSs was executed by FE-SEM, which confirmed that the doped products were sheet-shaped and growth in large quantity. Here, the analytical efficiency of the NSs was applied for a selective adsorption of iron(III ion prior to detection by inductively coupled plasma-optical emission spectrometry (ICP-OES. The selectivity of NSs towards various metal ions, including Au(III, Cd(II, Co(II, Cr(III, Fe(III, Pd(II, and Zn(II was analyzed. Conclusions Based on the selectivity study, it was confirmed that the selectivity of doped NSs phase was the most towards Fe(III ion. The static adsorption capacity for Fe(III was calculated to be 110.06 mgg−1. Results from adsorption isotherm also verified that the adsorption process was mainly monolayer-adsorption onto a surface containing a finite number of CuO-TiO2 NSs adsorption sites.

  2. INFLUENŢA SELENITULUI DE Fe(III ŞI A INTENSITĂŢII DE ILUMINARE ASUPRA CONŢINUTULUI DE FICOBILIPROTEINE, SELENIU ŞI FIER ÎN BIOMASA CIANOBACTERIEI SPIRULINA PLATENSIS

    Directory of Open Access Journals (Sweden)

    Valentina BULIMAGA

    2017-03-01

    Full Text Available Productivitatea spirulinei şi onţinutul de fier în biomasă au înregistrat valori mai înalte la iluminare mai intensă (5500 lx, comparativ cu 3500 lx, iar acumularea ficobiliproteinelor în biomasa de spirulină a fost mai semnificativă la 3500 lx. Conţinutul de seleniu acumulat în fracţia de ficobiliproteine a înregistrat valori mai sporite cu majorarea concentraţiei selenitului de fier, fiind maxime la concentraţia acestuia de 45 mg/l la ambele intensităţi de iluminare. La 3500 lx conţinutul de seleniu în extractul sumar de ficobiliproteine a fost de 1,4-1,5 ori mai majorat, comparativ cu cel atestat la 5500 lx.EFFECTS OF Fe(III SELENITE AND LIGHT INTENSITY ON THE ACCUMULATION OF PHYCOBILIPROTEINS, SELENIUM AND IRON IN BIOMASS OF CYANOBACTERIUM SPIRULINA PLATENSISSpirulina productivity and iron content in biomass recorded higher values at light intensity 5500 lx, compared to 3500 lx, but phycobiliproteins accumulation in spirulina biomass was more significant at 3500 lx. The content of the accumulated selenium in the phycobiliproteins registered the increased values with the increasing of selenite concentra­tion, attesting its maximum value at 45 mg/l, at the both light intensity. Selenium content in the phycobiliproteins at 3500 lx was by 1.4-1.5 times higher, compared to that registered at 5500 lx.

  3. Linking Local Environments and Hyperfine Shifts: A Combined Experimental and Theoretical 31P and 7Li Solid–State NMR Study of Paramagnetic Fe(III) Phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jonsik [Stony Brook Univ., NY (United States); Middlemiss, Derek S. [Stony Brook Univ., NY (United States); Chernova, Natasha [Univ. of Cambridge (United Kingdom); Zhu, Ben Y.H. [Stony Brook Univ., NY (United States); Masquelier, Christian [SUNY Binghamton, NY (United States); Grey, Clare P. [Stony Brook Univ., NY (United States); Universite de Picardie Jules Verne, Amiens (France)

    2010-11-05

    Iron phosphates (FePO4) are among the most promising candidate materials for advanced Li-ion battery cathodes. This work reports upon a combined nuclear magnetic resonance (NMR) experimental and periodic density functional theory (DFT) computational study of the environments and electronic structures occurring in a range of paramagnetic Fe(III) phosphates comprising FePO4 (heterosite), monoclinic Li3Fe2(PO4)3 (anti-NASICON A type), rhombohedral Li3Fe2(PO4)3 (NASICON B type), LiFeP2O7, orthorhombic FePO4·2H2O (strengite), monoclinic FePO4·2H2O (phosphosiderite), and the dehydrated forms of the latter two phases. Many of these materials serve as model compounds relevant to battery chemistry. The 31P spin-echo mapping and 7Li magic angle spinning NMR techniques yield the hyperfine shifts of the species of interest, complemented by periodic hybrid functional DFT calculations of the respective hyperfine and quadrupolar tensors. A Curie-Weiss-based magnetic model scaling the DFT-calculated hyperfine parameters from the ferromagnetic into the experimentally relevant paramagnetic state is derived and applied, providing quantitative finite temperature values for each phase. The sensitivity of the hyperfine parameters to the composition of the DFT exchange functional is characterized by the application of hybrid Hamiltonians containing admixtures 0%, 20%, and 35% of Fock exchange. Good agreement between experimental and calculated values is obtained, provided that the residual magnetic couplings persisting in the paramagnetic state are included. The potential applications of a similar combined experimental and theoretical NMR approach to a wider range of cathode materials are discussed.

  4. Bioalteration of synthetic Fe(III)-, Fe(II)-bearing basaltic glasses and Fe-free glass in the presence of the heterotrophic bacteria strain Pseudomonas aeruginosa: Impact of siderophores

    Science.gov (United States)

    Perez, Anne; Rossano, Stéphanie; Trcera, Nicolas; Huguenot, David; Fourdrin, Chloé; Verney-Carron, Aurélie; van Hullebusch, Eric D.; Guyot, François

    2016-09-01

    This study aims to evaluate the role of micro-organisms and their siderophores in the first steps of the alteration processes of basaltic glasses in aqueous media. In this regard, three different types of glasses - with or without iron, in the reduced Fe(II) or oxidized Fe(III) states - were prepared on the basis of a simplified basaltic glass composition. Control and Pseudomonas aeruginosa inoculated experiments were performed in a buffered (pH 6.5) nutrient depleted medium to stimulate the production of the pyoverdine siderophore. Results show that the presence of P. aeruginosa has an effect on the dissolution kinetics of all glasses as most of the calculated elemental release rates are increased compared to sterile conditions. Reciprocally, the composition of the glass in contact with P. aeruginosa has an impact on the bacterial growth and siderophore production. As an essential nutrient for this microbial strain, Fe notably appears to play a central role during biotic experiments. Its presence in the glass stimulates the bacterial growth and minimizes the synthesis of pyoverdine. Moreover the initial Fe2+/Fe3+ ratio in the glasses modulates this synthesis, as pyoverdine is not detected at all in the system in contact with Fe(III)-bearing glass. Finally, the dissolution rates appear to be correlated to siderophore concentrations as they increase with respect to sterile experiments in the order Fe(III)-bearing glass < Fe(II)-bearing glass < Fe-free glass. This increase is attributed to complexation reactions between siderophores and Fe or Al for Fe(II)-bearing glass or Fe-free glass, respectively. The dissolution of an Fe-free glass is significantly improved in the presence of bacteria, as initial dissolution rates are increased by a factor of 3. This study attests to the essential role of siderophores in the P. aeruginosa-promoted dissolution processes of basaltic glasses as well as to the complex relationships between the nutritional potential of the glass and

  5. Schiff base ligand derived from (±trans-1,2-cyclohexanediamine and its Cu(II, Co(II, Zn(II and Mn(II complexes: Synthesis, characterization, styrene oxidation and hydrolysis study of the imine bond in Cu(II Schiff base complex

    Directory of Open Access Journals (Sweden)

    Sarkheil Marzieh

    2016-01-01

    Full Text Available A Schiff base ligand (H2L derived from 2´-hydroxypropiophenone and (±trans-1,2-cyclohexanediamine was synthesized. The reactions of MCl2.xH2O (M =Cu(II, Co(II, Zn(II and Mn(IIwith the di-Schiff base ligand (H2L were studied. This ligand when stirred with 1 equivalent of CuCl2.2H2O in the solution of ethanol and chloroform undergoes partial hydrolysis of the imino bond and the resultant tridentate ligand (HL′immediately forms complex[CuL´Cl]∙3/2CHCl3(1with N2O coordination sphere. Under the same condition, the reaction of H2L with MCl2.xH2O (M = Co(II (3, Zn(II (4 and Mn(II (5 gave complexes[ML]•1/2CHCl3∙3/2H2O (3-5with N2O2 coordination sphere and no hydrolytic cleavage was occurred. Also, the reaction of H2L with CuCl2.2H2O in THF gave the complex CuL (2with N2O2 coordination sphere. The ligand and complexes were characterized by FTIR, UV-Vis, 1H NMRand elemental analysis. The homogeneous catalytic activity of the complexes1, 3 and 5wasevaluated for the oxidation of styrene using tert-butyl hydroperoxide (TBHP as oxidant. Finally, the copper(II complex(1encapsulated in the nanopores of zeolite-Y by flexible ligand method (CuL´-Yand its encapsulation was ensured by different studies. The catalytic performance of heterogeneous catalyst in the styrene oxidation with TBHP was investigated. The catalytic tests showed that the homogenous and heterogeneous catalysts were active in the oxidation of styrene.

  6. Spectrophotometric Determination of Chromium(III and Iron(III by used of 2-((E-(1H-Benzo[D]Imidazol2-YlDiazenyl-5-((E-Benzylideneimino Phenol;(BIADPI as Organic Reagent

    Directory of Open Access Journals (Sweden)

    Khalid J. Al-Adilee

    2016-09-01

    Full Text Available The azo reagent 2-((E-(1H-benzo[d]imidazol2-yldiazenyl-5-((E-benzyl ideneiminophenol(BIADPI was prepared and examined by using element analysis(C.H.N.,UV-Vis., Mass spectrum, 1H-NMR spectrum and infrared spectra. A sensitive and selective spectrophotometric method is proposed for the rapid determination of iron (III and chromium(III using (BIADPI , as spectrophotometer reagent. The reaction between this reagent with chromium(III and iron (III is instantaneous at (586,536 nm (λmax and pH=(7.5,4 to form perpul complexes having a mole ratio 1 : 2 (metal : ligand for Cr (III and Fe(III the absorbance remains stable for over 24 hours. Beer's law is obeyed in the rang of (1-14 μg.ml-1 and (1-21 μg.ml-1with molar absorptivity (Є = (7.768x105 , 9.3575x105 L.mol-1.cm-1 and a detection limit of (0.275-0.14 μg.ml-1 obtained respectively. The precision and accuracy were obtained to be R.S.D%=(0.9-0.467%,Re%=(99.1-98.2-% and Erel%= (-1.8 - 0.9%.The method is successfully employed for the determination of iron(III in Pharmaceutical preparations(Anemiadrugs.The most important interferences were due to Ni(II, Zn(II, Co(II, Cd(II, Cu(IIand Hg(II and suitable masking agents were used.

  7. New non-toxic transition metal nanocomplexes and Zn complex-silica xerogel nanohybrid: Synthesis, spectral studies, antibacterial, and antitumor activities

    Science.gov (United States)

    Shebl, Magdy; Saif, M.; Nabeel, Asmaa I.; Shokry, R.

    2016-08-01

    A new chromone Schiff base and its complexes of Cu(II), Ni