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Sample records for aqueous ion testing

  1. Removal of fluoride ions from aqueous solution by waste mud

    Energy Technology Data Exchange (ETDEWEB)

    Kemer, Baris; Ozdes, Duygu; Gundogdu, Ali; Bulut, Volkan N.; Duran, Celal [Karadeniz Technical University, Faculty of Arts and Sciences, Department of Chemistry, 61080 Trabzon (Turkey); Soylak, Mustafa, E-mail: soylak@erciyes.edu.tr [Erciyes University, Faculty of Arts and Sciences, Department of Chemistry, 38039 Kayseri (Turkey)

    2009-09-15

    The present study was carried out to assess the ability of original waste mud (o-WM) and different types of activated waste mud which are acid-activated (a-WM) and precipitated waste mud (p-WM), in order to remove excess of fluoride from aqueous solution by using batch technique. The p-WM exhibited greater performance than the others. Adsorption studies were conducted as a function of pH, contact time, initial fluoride concentration, adsorbent concentration, temperature, etc. Studies were also performed to understand the effect of some co-existing ions present in aqueous solutions. Adsorption process was found to be almost independent of pH for all types of waste mud. Among the kinetic models tested for p-WM, pseudo-second-order model fitted the kinetic data well with a perfect correlation coefficient value of 1.00. It was found that the adequate time for the adsorption equilibrium of fluoride was only 1 h. Thermodynamic parameters including the Gibbs free energy ({Delta}G{sup o}), enthalpy ({Delta}H{sup o}), and entropy ({Delta}S{sup o}) revealed that adsorption of fluoride ions on the p-WM was feasible, spontaneous and endothermic in the temperature range of 0-40 deg. C. Experimental data showed a good fit with the Langmuir and Freundlich adsorption isotherm models. Results of this study demonstrated the effectiveness and feasibility of WM for removal of fluoride ions from aqueous solution.

  2. Aqueous vanadium ion dynamics relevant to bioinorganic chemistry: A review.

    Science.gov (United States)

    Kustin, Kenneth

    2015-06-01

    Aqueous solutions of the four highest vanadium oxidation states exhibit four diverse colors, which only hint at the diverse reactions that these ions can undergo. Cationic vanadium ions form complexes with ligands; anionic vanadium ions form complexes with ligands and self-react to form isopolyanions. All vanadium species undergo oxidation-reduction reactions. With a few exceptions, elucidation of the dynamics of these reactions awaited the development of fast reaction techniques before the kinetics of elementary ligation, condensation, reduction, and oxidation of the aqueous vanadium ions could be investigated. As the biological roles played by endogenous and therapeutic vanadium expand, it is appropriate to bring the results of the diverse kinetics studies under one umbrella. To achieve this goal this review presents a systematic examination of elementary aqueous vanadium ion dynamics.

  3. Adsorption of lead ions from aqueous solutions using clinoptilolite

    OpenAIRE

    Golomeova, Mirjana; Zendelska, Afrodita; Krstev, Boris; Golomeov, Blagoj; Blažev, Krsto; Krstev, Aleksandar

    2014-01-01

    The adsorption of lead ions from synthetic aqueous solutions was performed by using natural zeolite (clinoptilolite). In order to determine the effectivity of clinoptilolite a series of experiments were performed under batch conditions from single ion solutions. Experiments were carried out at different initial concentration of lead ions, different initial pH values and different adsorbent mass. The adsorption kinetics is reasonably fast. It means that in the first 20 min approximately 90...

  4. A new strategy to stabilize oxytocin in aqueous solutions : I. The effects of divalent metal ions and citrate buffer

    NARCIS (Netherlands)

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J. M.; Hinrichs, Wouter L. J.; Frijlink, Henderik W.

    2011-01-01

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na+and K+) and divalent metal ions (Ca2+, Mg2+, and Zn2+) were tested all as chloride salts. The effec

  5. Rate theory on water exchange in aqueous uranyl ion

    Science.gov (United States)

    Dang, Liem X.; Vo, Quynh N.; Nilsson, Mikael; Nguyen, Hung D.

    2017-03-01

    We report a classical rate theory approach to predict the exchange mechanism that occurs between water and aqueous uranyl ion. Using our water and ion-water polarizable force field and molecular dynamics techniques, we computed the potentials of mean force for the uranyl ion-water pair as a function of different pressures at ambient temperature. These potentials of mean force were used to calculate rate constants using transition rate theory; the transmission coefficients also were examined using the reactive flux method and Grote-Hynes approach. The computed activation volumes are positive; thus, the mechanism of this particular water-exchange is a dissociative process.

  6. A lithium ion battery using an aqueous electrolyte solution

    OpenAIRE

    Zheng Chang; Chunyang Li; Yanfang Wang; Bingwei Chen; Lijun Fu; Yusong Zhu; Lixin Zhang; Yuping Wu; Wei Huang

    2016-01-01

    Energy and environmental pollution have become the two major problems in today’s society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge vo...

  7. Heterocyclic ring based colorimetric and fluorescent chemosensor for transition metal ions in an aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Udhayakumari, Duraisamy [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Velmathi, Sivan, E-mail: velmathis@nitt.edu [Department of Chemistry, Organic and Polymer Synthesis Laboratory, National Institute of Technology, Tiruchirappalli 620015 (India); Boobalan, Maria susai [Department of Chemistry, St. Joseph' s College (Autonomous), Tiruchirappalli 620002 (India); Venkatesan, Parthiban; Wu, Shu-Pao [Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan, ROC (China)

    2015-02-15

    Heterocyclic ring based R1–R3 have been synthesized from the simple condensation method. R1–R3 exhibit highly selective and sensitive recognition towards transition metal ions in an aqueous medium via visual color change and were further confirmed by UV–vis and fluorescent spectroscopic methods. Fluorescent turn on and turn off behavior was observed for receptors tested with transition metal ions. The interaction of transition metal ions and receptors R1–R3 was confirmed to adopt 1:1 binding stoichiometry. Micromolar detection limit was found for R1–R3 with metal ions. DFT theoretical calculations were employed to understand the sensing mechanism of the sensors towards the metal ions. R1 and R2 were also successfully demonstrated as a fluorescent probe for detecting Cu{sup 2+} ions in living cells. - highlights: • R1–R3 act as colorimetric and fluorescent sensors for metal ions. • Receptors (R1–R3) detect Cu{sup 2+} ions in aqueous solution at nanomolar levels. • R1 and R2 act as a fluorescent probe for detecting Cu{sup 2+} ions in living cells.

  8. EXAFS studies of actinide ions in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Karim, D P; Georgopoulos, P; Knapp, G S

    1979-01-01

    The applicability of the EXAFS technique in the study of actinide systems is discussed. Uranium L/sub III/-edge spectra obtained on an in-lab rotating anode EXAFS facility are presented and analyzed for crystalline UO/sub 2/F/sub 2/ and aqueous solutions containing hexavalent uranium ions. Methods for the extension of the technique to more dilute systems are discussed.

  9. Ion Movement in Polypyrrole/Dodecylbenzenesulphonate Films in aqueous and non-aqueous electrolytes

    DEFF Research Database (Denmark)

    Vidanapathirana, K.; Careem, M.A.; Skaarup, Steen

    2002-01-01

    The electrochemical characteristics during the redox process of polypyrrole (PPy) films, prepared using dodecylbenzenesulphonate (DBS-) dopant species, have been investigated using a combination of cyclic voltammetry and Electrochemical Quartz Crystal Microbalance (EQCM) measurements. Investigati......The electrochemical characteristics during the redox process of polypyrrole (PPy) films, prepared using dodecylbenzenesulphonate (DBS-) dopant species, have been investigated using a combination of cyclic voltammetry and Electrochemical Quartz Crystal Microbalance (EQCM) measurements....... Investigations were carried out using aqueous and non-aqueous electrolytes to study the effect of solvent on the ion movement during redox processes. When PPy films are cycled in aqueous electrolytes transport of both anion and cation occurs during oxidation and reduction. However, when cycled in the nonaqueous...

  10. Metal ion removal from aqueous solution using physic seed hull.

    Science.gov (United States)

    Mohammad, Masita; Maitra, Saikat; Ahmad, Naveed; Bustam, Azmi; Sen, T K; Dutta, Binay K

    2010-07-15

    The potential of physic seed hull (PSH), Jantropha curcas L. as an adsorbent for the removal of Cd(2+) and Zn(2+) metal ions from aqueous solution has been investigated. It has been found that the amount of adsorption for both Cd(2+) and Zn(2+) increased with the increase in initial metal ions concentration, contact time, temperature, adsorbent dosage and the solution pH (in acidic range), but decreased with the increase in the particle size of the adsorbent. The adsorption process for both metal ions on PSH consists of three stages-a rapid initial adsorption followed by a period of slower uptake of metal ions and virtually no uptake at the final stage. The kinetics of metal ions adsorption on PSH followed a pseudo-second-order model. The adsorption equilibrium data were fitted in the three adsorption isotherms-Freundlich, Langmuir and Dubinin-Radushkevich isotherms. The data best fit in the Langmuir isotherm indication monolayer chemisorption of the metal ions. The adsorption capacity of PSH for both Zn(2+) and Cd(2+) was found to be comparable with other available adsorbents. About 36-47% of the adsorbed metal could be leached out of the loaded PSH using 0.1M HCl as the eluting medium.

  11. A new strategy to stabilize oxytocin in aqueous solutions: I. The effects of divalent metal ions and citrate buffer.

    Science.gov (United States)

    Avanti, Christina; Amorij, Jean-Pierre; Setyaningsih, Dewi; Hawe, Andrea; Jiskoot, Wim; Visser, Jan; Kedrov, Alexej; Driessen, Arnold J M; Hinrichs, Wouter L J; Frijlink, Henderik W

    2011-06-01

    In the current study, the effect of metal ions in combination with buffers (citrate, acetate, pH 4.5) on the stability of aqueous solutions of oxytocin was investigated. Both monovalent metal ions (Na(+) and K(+)) and divalent metal ions (Ca(2+), Mg(2+), and Zn(2+)) were tested all as chloride salts. The effect of combinations of buffers and metal ions on the stability of aqueous oxytocin solutions was determined by RP-HPLC and HP-SEC after 4 weeks of storage at either 4°C or 55°C. Addition of sodium or potassium ions to acetate- or citrate-buffered solutions did not increase stability, nor did the addition of divalent metal ions to acetate buffer. However, the stability of aqueous oxytocin in aqueous formulations was improved in the presence of 5 and 10 mM citrate buffer in combination with at least 2 mM CaCl(2), MgCl(2), or ZnCl(2) and depended on the divalent metal ion concentration. Isothermal titration calorimetric measurements were predictive for the stabilization effects observed during the stability study. Formulations in citrate buffer that had an improved stability displayed a strong interaction between oxytocin and Ca(2+), Mg(2+), or Zn(2+), while formulations in acetate buffer did not. In conclusion, our study shows that divalent metal ions in combination with citrate buffer strongly improved the stability of oxytocin in aqueous solutions.

  12. A lithium ion battery using an aqueous electrolyte solution

    Science.gov (United States)

    Chang, Zheng; Li, Chunyang; Wang, Yanfang; Chen, Bingwei; Fu, Lijun; Zhu, Yusong; Zhang, Lixin; Wu, Yuping; Huang, Wei

    2016-06-01

    Energy and environmental pollution have become the two major problems in today’s society. The development of green energy storage devices with good safety, high reliability, high energy density and low cost are urgently demanded. Here we report on a lithium ion battery using an aqueous electrolyte solution. It is built up by using graphite coated with gel polymer membrane and LISICON as the negative electrode, and LiFePO4 in aqueous solution as the positive electrode. Its average discharge voltage is up to 3.1 V and energy density based on the two electrode materials is 258 Wh kg‑1. It will be a promising energy storage system with good safety and efficient cooling effects.

  13. A Type of Lithium-ion Battery Based on Aqueous electrolyte

    Institute of Scientific and Technical Information of China (English)

    G.J.Wang; N.H.Zhao; L.J.Fu; B.Wang; Y.P.Wu

    2007-01-01

    1 Introduction A new type of rechargeable lithium ion battery with an aqueous electrolyte was announced by W. Li et al. in 1994[1].This type of battery uses the lithium intercalation compounds LiMn2O4 and VO2 as electrode materials and an alkaline aqueous electrolytic solution. By this combination, the disadvantages of the non-aqueous Li-ion battery type, i.e. high cost and safety problems could be faded away[2]. So this type of aqueous Li-ion battery was regarded as the promising power for electric veh...

  14. Bioactive and Antibacterial Glass Powders Doped with Copper by Ion-Exchange in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Marta Miola

    2016-05-01

    Full Text Available In this work, two bioactive glass powders (SBA2 and SBA3 were doped with Cu by means of the ion-exchange technique in aqueous solution. SBA2 glass was subjected to the ion-exchange process by using different Cu salts (copper(II nitrate, chloride, acetate, and sulphate and concentrations. Structural (X-ray diffraction-XRD, morphological (Scanning Electron Microscopy-SEM, and compositional (Energy Dispersion Spectrometry-EDS analyses evidenced the formation of crystalline phases for glasses ion-exchanged in copper(II nitrate and chloride solutions; while the ion-exchange in copper(II acetate solutions lead to the incorporation of higher Cu amount than the ion-exchange in copper(II sulphate solutions. For this reason, the antibacterial test (inhibition halo towards S. aureus was performed on SBA2 powders ion-exchanged in copper(II acetate solutions and evidenced a limited antibacterial effect. A second glass composition (SBA3 was developed to allow a greater incorporation of Cu in the glass surface; SBA3 powders were ion-exchanged in copper(II acetate solutions (0.01 M and 0.05 M. Cu-doped SBA3 powders showed an amorphous structure; morphological analysis evidenced a rougher surface for Cu-doped powders in comparison to the undoped glass. EDS and X-ray photoelectron spectroscopy (XPS confirmed the Cu introduction as Cu(II ions. Bioactivity test in simulated body fluid (SBF showed that Cu introduction did not alter the bioactive behaviour of the glass. Finally, inhibition halo test towards S. aureus evidenced a good antimicrobial effect for glass powders ion-exchanged in copper(II acetate solutions 0.05 M.

  15. Stabilities and partitioning of arenonium ions in aqueous media.

    Science.gov (United States)

    Lawlor, D A; More O'Ferrall, R A; Rao, S N

    2008-12-31

    The phenathrenonium ion is formed as a reactive intermediate in the solvolysis of 9-dichloroacetoxy-9,10-dihydrophenanthrene in aqueous acetonitrile and undergoes competing reactions with water acting as a base and nucleophile. Measurements of product ratios in the presence of azide ion as a trap and 'clock' yield rate constants kp = 3.7 x 10(10) and kH2O = 1.5 x 10(8) s(-1), respectively. Combining these with rate constants for the reverse reactions (protonation of phenanthrene and acid-catalyzed aromatization of its water adduct) gives equilibrium constants pKa = -20.9 and pK(R) = -11.6. For a series of arenonium and benzylic cations, correlation of log kp with pKa, taking account of the limit to kp set by the relaxation of water (10(11) s(-1)), leads to extrapolation of kp = 9.0 x 10(10) s(-1) and pKa = -24.5 for the benzenonium ion and kp = 6.5 x 10(10) s(-1) and pKa = -22.5 for the 1-naphthalenonium ion. Combining these pKa's with estimates of equilibrium constants pKH2O for the hydration of benzene and naphthalene, and the relationship pKR = pKa + pKH2O based on Hess's law, gives pKR = -2.3 and -8.0 respectively, and highlights the inherent stability of the benzenonium ion. A correlation exists between the partitioning ratio, kp/kH2O, for carbocations reacting in water and KH2O the equilibrium constant between the respective reaction products, i.e., log(kp/kH2O) = 0.46pKH2O - 3.7. It implies that kp exceeds kH2O only when KH2O > 10(8). This is consistent with the proton transfer (a) possessing a lower intrinsic reactivity than reaction of the carbocation with water as a nucleophile and (b) being rate-determining in the hydration of alkenes (and dehydration of alcohols) except when the double bond of the alkene is unusually stabilized, as in the case of aromatic molecules.

  16. Experimental measurement and modeling of the distribution of solvent and ions between an aqueous phase and an ion exchange resin

    DEFF Research Database (Denmark)

    Christensen, Søren Gregers; Thomsen, Kaj

    2005-01-01

    The distribution of solutes and solvent between an aqueous solution of salt and an ion exchange resin has been measured at ambient temperature. The experiments have been performed for aqueous solutions of KNO3, KCl, Ca(NO3)2 and CaCl2 in the concentration range of 0-3N. The absorption has been...

  17. Adsorption of Cu2+ Ions From Aqueous Solutions Using Oxidized Multi-Walled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Soheil Sobhanardakani

    2015-06-01

    Full Text Available Copper ion (Cu2+ is one of the heavy metal ions that cause environmental pollution specifically in water. Copper ion cations are not biodegradable and tend to cumulate in living organisms. Consequently, the removal of Cu2+ in environmental samples plays an important role in environmental pollution monitoring. The purpose of the present work was to prepare oxidized Multi-Walled Carbon Nano Tubes (MWCNTs for removal of Cu2+ ions from aqueous solutions. This study was conducted under laboratory conditions. Multi-Walled Carbon Nano Tubes were oxidized and characterized by Fourier Transform Infrared Spectroscopy (FTIR, Scanning Electron Microscope (SEM and the Brunauer, Emmett, and Teller (BET methods. The effects of various factors, such as solution pH (3 - 9, adsorbent dose (0.006 - 0.06 g and contact time (10 - 120 minutes were investigated. Results showed that the suitable pH for Cu2+ ions removal was about 6.0, and the optimal dose was 0.03 g. Isotherm studies indicated that the Langmuir model fits the experimental data better than the Freundlich model. Maximum Cu2+ adsorption capacity was calculated as 200 mg g-1. The kinetics of the adsorption process was tested for the pseudo-first-order and pseudo-second-order models. The comparison among the models showed that the pseudo-second order model best described the adsorption kinetics. The results showed that oxidized MWCNTs can be used as a low cost adsorbent for the removal of Cu2+ ions from aqueous solutions.

  18. Removal and recovery of toxic metal ions from aqueous waste sites using polymer pendant ligands

    Energy Technology Data Exchange (ETDEWEB)

    Fish, D. [Lawrence Berkeley National Lab., CA (United States)

    1996-10-01

    The purpose of this project is to investigate the use of polymer pendant ligand technology to remove and recover toxic metal ions from DOE aqueous waste sites. Polymer pendant lgiands are organic ligands, anchored to crosslinked, modified divinylbenzene-polystyrene beads, that can selectively complex metal ions. The metal ion removal step usually occurs through a complexation or ion exchange phenomena, thus recovery of the metal ions and reuse of the beads is readily accomplished.

  19. Probing ion-specific effects on aqueous acetate solutions: Ion pairing versus water structure modifications

    Directory of Open Access Journals (Sweden)

    Tristan Petit

    2014-05-01

    Full Text Available The effect of monovalent cations (Li+, K+, NH4+, Na+ on the water structure in aqueous chloride and acetate solutions was characterized by oxygen K-edge X-ray absorption spectroscopy (XAS, X-ray emission spectroscopy, and resonant inelastic X-ray scattering (RIXS of a liquid microjet. We show ion- and counterion dependent effects on the emission spectra of the oxygen K-edge, which we attribute to modifications of the hydrogen bond network of water. For acetates, ion pairing with carboxylates was also probed selectively by XAS and RIXS. We correlate our experimental results to speciation data and to the salting-out properties of the cations.

  20. Enhancement of gaseous iodine emission by aqueous ferrous ions during the heterogeneous reaction of gaseous ozone with aqueous iodide.

    Science.gov (United States)

    Sakamoto, Yosuke; Enami, Shinichi; Tonokura, Kenichi

    2013-04-11

    Gaseous I2 formation from the heterogeneous reaction of gaseous ozone with aqueous iodide in the presence of aqueous ferrous ion (Fe(2+)) was investigated by electron impact ionization mass spectrometry. Emission of gaseous I2 increased as a function of the aqueous FeCl2 concentration, and the maximum I2 formation with Fe(2+) was about 10 times more than without Fe(2+). This enhancement can be explained by the OH(-) scavenging by Fe(3+) formed from Fe(2+) ozonation to produce colloidal Fe(OH)3. This mechanism was confirmed by measurements of aqueous phase products using a UV-vis spectrometer and an electrospray ionization mass spectrometer. We infer that such a pH-buffering effect may play the key role in general halogen activations.

  1. Electrochemical removal of indium ions from aqueous solution using iron electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Wei-Lung, E-mail: wlchou@sunrise.hk.edu.tw [Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 34 Chung-Chie Road, Sha-Lu, Taichung 433, Taiwan (China); Huang, Yen-Hsiang [Department of Safety, Health and Environmental Engineering, Hungkuang University, No. 34 Chung-Chie Road, Sha-Lu, Taichung 433, Taiwan (China)

    2009-12-15

    The removal of indium ions from aqueous solution was carried out by electrocoagulation in batch mode using an iron electrode. Various operating parameters that could potentially affect the removal efficiency were investigated, including the current density, pH variation, supporting electrolyte, initial concentration, and temperature. The optimum current density, supporting electrolyte concentration, and temperature were found to be 6.4 mA/cm{sup 2}, 0.003N NaCl, and 298 K, respectively. When the pH values lower than 6.1, the removal efficiencies of indium ions via electrocoagulation were up to 5 times greater than those by adding sodium hydroxide. The indium ion removal efficiency decreased with an increase in the initial concentration. Results for the indium ion removal kinetics at various current densities show that the kinetic rates conformed to the pseudo-second-order kinetic model with good correlation. The experimental data were also tested against different adsorption isotherm models for describing the electrocoagulation process. The adsorption of indium ions preferably fitting the Langmuir adsorption isotherm suggests monolayer coverage of adsorbed molecules.

  2. Tetraethyl Orthosilicate Coated Hydroxyapatite Powders for Lead Ions Removal from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Rodica V. Ghita

    2014-01-01

    Full Text Available The goal of this study was to synthetize and characterize a porous material based on tetraethyl orthosilicate (TEOS coated hydroxyapatite (HApTh after removal experiments of Pb2+ ions from aqueous solutions. In order to study the morphology and composition, the samples obtained after removal experiments of Pb2+ ions from aqueous solution with the initial Pb2+ ion concentrations of the aqueous solutions were 0.1 g·L−1 (HApTh-50 and 0.9 g·L−1 (HApTh-450 have been investigated by scanning electron microscopy (SEM equipped with an energy dispersive X-ray spectrometer (EDS, Fourier transform infrared spectroscopy (FTIR, and transmission electron microscopy (TEM. Removal experiments of Pb2+ ions were carried out in aqueous solutions with controlled concentration of Pb2+. After the removal experiment of Pb2+ ions from solutions, porous hydroxyapatite nanoparticles were transformed into HApTh-50 and HApTh-450 due to the adsorption of Pb2+ ions followed by a cation exchange reaction. The obtained results show that the porous HApTh nanopowders could be used for Pb2+ ions removal from aqueous solutions.

  3. Adsorption of copper (II), chromium (III), nickel (II) and lead (II) ions from aqueous solutions by meranti sawdust.

    Science.gov (United States)

    Rafatullah, M; Sulaiman, O; Hashim, R; Ahmad, A

    2009-10-30

    The present study proposed the use of meranti sawdust in the removal of Cu(II), Cr(III), Ni(II) and Pb(II) ions from synthetic aqueous solutions. Batch adsorption studies showed that meranti sawdust was able to adsorb Cu(II), Cr(III), Ni(II) and Pb(II) ions from aqueous solutions in the concentration range 1-200mg/L. The adsorption was favoured with maximum adsorption at pH 6, whereas the adsorption starts at pH 1 for all metal ions. The effects of contact time, initial concentration of metal ions, adsorbent dosage and temperature have been reported. The applicability of Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm was tried for the system to completely understand the adsorption isotherm processes. The adsorption kinetics tested with pseudo-first-order and pseudo-second-order models yielded high R(2) values from 0.850 to 0.932 and from 0.991 to 0.999, respectively. The meranti sawdust was found to be cost effective and has good efficiency to remove these toxic metal ions from aqueous solution.

  4. Aqueous Rechargeable Zinc/Aluminum Ion Battery with Good Cycling Performance.

    Science.gov (United States)

    Wang, Faxing; Yu, Feng; Wang, Xiaowei; Chang, Zheng; Fu, Lijun; Zhu, Yusong; Wen, Zubiao; Wu, Yuping; Huang, Wei

    2016-04-13

    Developing rechargeable batteries with low cost is critically needed for the application in large-scale stationary energy storage systems. Here, an aqueous rechargeable zinc//aluminum ion battery is reported on the basis of zinc as the negative electrode and ultrathin graphite nanosheets as the positive electrode in an aqueous Al2(SO4)3/Zn(CHCOO)2 electrolyte. The positive electrode material was prepared through a simple electrochemically expanded method in aqueous solution. The cost for the aqueous electrolyte together with the Zn negative electrode is low, and their raw materials are abundant. The average working voltage of this aqueous rechargeable battery is 1.0 V, which is higher than those of most rechargeable Al ion batteries in an ionic liquid electrolyte. It could also be rapidly charged within 2 min while maintaining a high capacity. Moreover, its cycling behavior is also very good, with capacity retention of nearly 94% after 200 cycles.

  5. EFFECT OF CERIUM ION IMPLANTATION ON THE AQUEOUS CORROSION BEHAVIOR OF ZIRCONIUM

    Institute of Scientific and Technical Information of China (English)

    D.Q. Peng; X.D. Bai; Q.G. Zhou; X.W. Chen; R.H. Yu; X.Y. Liu

    2004-01-01

    In order to study the influence of cerium ion implantation on the aqueous corrosion behavior of zirconium, specimens were implanted by cerium ions with a dosage range from 1 ×1016 to 1 ×1017 ions/cm2 at about 150℃, using MEWA source at an acceler ative voltage of 40kV. The valence of the surface layer was analyzed by X-ray photoelectron spectroscopy (XPS); Three-sweep potentiodynamic polarization measurement was employed to value the aqueous corrosion resistance of zirconium in a 0.5mol/L H2SO4 solution. It was found that a remarkable decline in the aqueous corrosion behavior of zirconium implanted with cerium ions compared with that of the as-received zirconium. Finally, the mechanism of the corrosion resistance decline of the cerium-implanted zirconium is discussed.

  6. Removal of lead and zinc ions from aqueous solutions using clinoptilolite

    OpenAIRE

    Golomeova, Mirjana; Zendelska, Afrodita; Krstev, Boris; Golomeov, Blagoj; Blažev, Krsto

    2014-01-01

    The removed of lead and zinc ions from synthetic aqueous solutions was performed using clinoptilolite. In order to determine the effectivity of clinoptilolite a series of experiments were performed under batch conditions from single ion solutions. Experiments were carried out at different initial ions concentration, different initial pH values and different adsorbent mass. The adsorption kinetics is reasonably fast. It means that in the first 20 min approximately 90% o...

  7. The influence of ferrous ions on the efficiency of aqueous photocatalytic oxidation of 2-ethoxy ethanol

    OpenAIRE

    D. Klauson; Preis, S

    2005-01-01

    The complex influence of ferrous ions on the efficiency of aqueous photocatalytic oxidation (PCO) of 2-ethoxyethanol (2-EE) was examined. A drastic efficiency increase at lower concentrations of ferrous ions was observed to change to a sharp decrease at higher concentrations. An explanation was proposed for the observed phenomena based on the low sensitivity of the pollutant towards radical-oxidation reactions and the competitive adsorption of metallic ions and 2-EE on the TiO2 su...

  8. Removal of heavy metal ions from aqueous solution by zeolite synthesized from fly ash.

    Science.gov (United States)

    He, Kuang; Chen, Yuancai; Tang, Zhenghua; Hu, Yongyou

    2016-02-01

    Zeolite was synthesized from coal fly ash by a fusion method and was used for the removal of heavy metal ions (Pb(2+), Cd(2+), Cu(2+), Ni(2+), and Mn(2+)) in aqueous solutions. Batch method was employed to study the influential parameters such as adsorbent dosage, pH, and coexisting cations. Adsorption isotherms and kinetics studies were carried out in single-heavy and multiheavy metal systems, respectively. The Langmuir isotherm model fitted to the equilibrium data better than the Freundlich model did, and the kinetics of the adsorption were well described by the pseudo-second-order model, except for Cd(2+) and Ni(2+) ions which were fitted for the pseudo-first-order model in the multiheavy metal system. The maximum adsorption capacity and the distribution coefficients exhibited the same sequence for Pb(2+) > Cu(2+) > Cd(2+) > Ni(2+) > Mn(2+) in both single- and multiheavy metal systems. In the end, the adsorption capacity of zeolite was tested using industrial wastewaters and the results demonstrated that zeolite could be used as an alternative adsorbent for the removal of heavy metal ions from industrial wastewater.

  9. The removal of lead ions using zeolite nanoparticles from aqueous solutions

    Science.gov (United States)

    Joshi, Parth

    2016-05-01

    The experiment for adsorption of lead ions from its aqueous solutions were carried out at room temperature and initial concentration of lead ions as well as after adsorption were determined by UV-Visible spectrophotometer. The effect of various parameters such as contact time, zeolite nanoparticles dosage and initial concentration of lead ions on the adsorption capacity of zeolite nanoparticles were studied in batch experiment. The kinetics of the adsorption processes was studied by using pseudo-first order and pseudo-second order. The pseudo-second order kinetic model provided the best correlation of the used experimental data compared to the pseudo-first order. The maximum lead ions adsorbed was found to be 43.91 mg/g. The present study indicated that zeolite nanoparticles could be used as an efficient adsorbent for removal of lead ions from aqueous solution.

  10. Removal of Cadmium Ions from Aqueous Solution by Silicate-incorporated Hydroxyapatite

    Institute of Scientific and Technical Information of China (English)

    SHI Hebin; ZHONG Hong; LIU Yu; DENG Jinyang

    2007-01-01

    This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate-incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate-incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite,which were in favor of enhancing the cadmium ion sorpfion capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions.

  11. The Influence of Iron Ions on the Aqueous Photocatalytic Oxidation of Deicing Agents

    Directory of Open Access Journals (Sweden)

    D. Klauson

    2007-01-01

    Full Text Available An experimental research into aqueous photocatalytic oxidation (PCO of the deicing compounds, 2-ethoxyethanol (2-EE, diethylene glycol monomethyl ether (DEGMME, and ethylene glycol (EG was undertaken. The addition of iron ions to the acidic aqueous solutions to be treated displayed complex influence on the oxidation efficiency of the above mentioned substances, resulting in a sharp increase of the PCO efficiency at smaller concentrations of iron ions followed by a drastic decrease with the increasing iron ion concentrations. The phenomena observed can be explained by the electron scavenging effect of the iron ions and the competitive adsorption of iron ions and the oxidized substances on titanium dioxide surface. The carbonic acids determined as the PCO by-products allow outlining some reaction pathways for the substances under consideration.

  12. Removal of Cadmium and Lead Ions from Aqueous Solution by Nanocrystalline Magnetite Through Mechanochemical Activation

    OpenAIRE

    Mohsen Hosseinzadeh; Seyyed Ali Seyyed Ebrahimi; Shahram Raygan; Seyed Morteza Masoudpanah

    2016-01-01

    In this study, the removal of cadmium and lead ions from aqueous solution by nanocrystalline magnetite was investigated. The nanocrystalline magnetite was synthesized by mechanochemical activation of hematite in a high energy planetary mill in argon atmosphere for 45 hours. The ability of the synthesized nanocrystalline magnetite for removal of Cd(II) and Pb(II) from aqueous solutions was studied in a batch reactor under different experimental conditions with different pHs, contact times, ini...

  13. Characterization and use of Moringa oleifera seeds as biosorbent for removing metal ions from aqueous effluents.

    Science.gov (United States)

    Araújo, Cleide S T; Alves, Vanessa N; Rezende, Hélen C; Almeida, Ione L S; de Assunção, Rosana M N; Tarley, César R T; Segatelli, Mariana G; Coelho, Nivia M Melo

    2010-01-01

    Moringa oleifera seeds were investigated as a biosorbent for removing metal ions from aqueous effluents. The morphological characteristics as well as the chemical composition of M. oleifera seeds were evaluated using Fourier Transform Infrared (FT-IR) Spectroscopy, Thermogravimetric Analysis (TGA), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The FT-IR spectra showed the presence of lipids and protein components. Scanning electron micrographs showed that Moringa seeds have an adequate morphological profile for the retention of metal ions. The results suggest that M. oleifera seeds have potential application in Cd(II), Pb(II), Co(II), Cu(II) and Ag(I) decontamination from aqueous effluents.

  14. Free energy landscapes of ion coordination in aqueous solution.

    Science.gov (United States)

    Brancato, Giuseppe; Barone, Vincenzo

    2011-11-10

    We show how the fruitful concept of free energy landscape, as invoked in the description of complex biological systems, can be rather easily extended to build up a simple and accurate picture about solvent coordination around ions. This may represent a revealing key element for the qualitative and quantitative physical-chemical interpretation of a large number of phenomena occurring in solution, such as water exchange mechanisms, ion mobility, solvation dynamics, ion channel selectivity, and so on. In particular, using a computational approach rooted into molecular dynamics simulations and enhanced sampling techniques, we show how the free energy landscapes of ion coordination in solution can be very easily and accurately obtained in a number of illustrative examples.

  15. Aqueous batteries based on mixed monovalence metal ions: a new battery family.

    Science.gov (United States)

    Chen, Liang; Zhang, Leyuan; Zhou, Xufeng; Liu, Zhaoping

    2014-08-01

    As existing battery technologies struggle to meet the requirements for widespread use in the field of large-scale energy storage, new concepts are urgently needed to build batteries with high energy density, low cost, and good safety. Here, we demonstrate two new aqueous batteries based on two monovalence metal ions (Li(+) /K(+) and Na(+) /K(+) ) as charge-transfer ions, Ni1 Zn1 HCF/TiP2 O7 and Ni1 Zn1 HCF/NaTi2 (PO4 )3 . These new batteries are unlike the conventional "rocking-chair" aqueous metal-ion batteries based on the migration of one type of shuttle ion between cathode and anode. They can deliver specific energy of 46 Wh kg(-1) and 53 Wh kg(-1) based on the total mass of active materials; this is superior to current aqueous battery systems based on sodium-ion and/or potassium-ion technologies. These two new batteries together with the previously developed Li(+) /Na(+) mixed-ion battery not only constitute a new battery family for energy storage, but also greatly broaden our horizons for battery research.

  16. Biosorption of lead from aqueous solutions by ion-imprinted tetraethylenepentamine modified chitosan beads.

    Science.gov (United States)

    Liu, Bingjie; Chen, Wei; Peng, Xiaoning; Cao, Qiqi; Wang, Qianrui; Wang, Dongfeng; Meng, Xianghong; Yu, Guangli

    2016-05-01

    In this paper, the bio-based ion-imprinted tetraethylenepentamine (TEPA) modified chitosan beads using Pb(II) as imprinted ions (Pb-ITMCB) were chemically synthesized, characterized and applied to selectively adsorb Pb(II) ions from aqueous solutions containing other metal ions, which has the same concentration as that of Pb(II) ions. Batch adsorption experiments were performed to evaluate the adsorption conditions, selectivity and reusability. FTIR, SEM and TEM technologies were used to elucidate the mechanism of Pb-ITMCB adsorbing Pb(II) ions. The results showed that the adsorption capacity of Pb-ITMCB for Pb(II) ions reached 259.68 mg/g at pH 6, 40 °C. The adsorption data could be fitted well with pseudo-second order kinetics model and Langmuir isotherm model. Compared with other metal cations, Pb(II) ions showed an overall affinity of being adsorbed by Pb-ITMCB. With the participation of active groups including NH2, NH and OH, the adsorption reaction took place both inside and on the surface of Pb-ITMCB. It indicated that Pb-ITMCB is a comparatively promising biosorbent for selective removal of Pb(II) ions from aqueous solutions.

  17. Fluorescent zinc-terpyridine complex containing coordinated peroxo counter ion in aqueous medium

    Indian Academy of Sciences (India)

    S Kapoor; M S Sastry

    2000-08-01

    We describe a mixed ligand-zinc (10) complex containing coordinated peroxo ion and 2,2'2"-terpyridine and exhibiting fluorescence in the visible region (473 nm) on excitation at 390 nm in aqueous medium at room temperature. We also discuss the unusual phenomenon of enhancement of this fluorescence intensity on addition of some transition metal ions (35, 310, 40 and 39 electronic configurations).

  18. Removal of Heavy Metal Ions From Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    maziar noei

    2014-12-01

    Full Text Available The removal of Zn(II, V(II,  by  silica aerogel has been found to be concentration, , contact time, adsorbent dose and temperature dependent. ion exchange are the major removal mechanisms involved. The adsorption isotherm studies clearly indicated that the adsorptive behaviour of metal ions on silica aerogel  was satisfied. The applicability of the Lagergren kinetic model has also been investigated. Thermodynamic constant (Kad , standard free energy ( ∆G0 ,enthalpy (∆H0 and entropy (∆S0 were calculated for predicting the nature of adsorption

  19. Structure, hydrolysis and diffusion of aqueous vanadium ions from Car-Parrinello molecular dynamics

    CERN Document Server

    Jiang, Zhen; Alexandrov, Vitaly

    2016-01-01

    A molecular level understanding of the properties of electroactive vanadium species in aqueous solution is crucial for enhancing the performance of vanadium redox flow batteries (RFB). Here, we employ Car-Parrinello molecular dynamics (CPMD) simulations based on density functional theory to investigate the hydration structures, first hydrolysis reaction and diffusion of aqueous V$^{2+}$, V$^{3+}$, VO$^{2+}$, and VO$_2^+$ ions at 300 K. The results indicate that the first hydration shell of both V$^{2+}$ and V$^{3+}$ contains six water molecules, while VO$^{2+}$ is coordinated to five and VO$_2^+$ to three water ligands. The first acidity constants (p$K_\\mathrm{a}$) estimated using metadynamics simulations are 2.47, 3.06 and 5.38 for aqueous V$^{3+}$, VO$_2^+$ and VO$^{2+}$, respectively, while V$^{2+}$ is predicted to be a fairly weak acid in aqueous solution with a p$K_\\mathrm{a}$ value of 6.22. We also show that the presence of chloride ions in the first coordination sphere of the aqueous VO$_2^+$ ion has a...

  20. Strengthening of the Coordination Shell by Counter Ions in Aqueous Th 4+ Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Atta-Fynn, Raymond; Bylaska, Eric J.; de Jong, Wibe A.

    2016-12-29

    The presence of counter ions in solutions containing highly charged metal cations can trigger processes such as ion-pair formation, hydrogen bond breakages and subsequent reformation, and ligand exchanges. In this work, it is shown how halide (Cl-, Br-) and perchlorate (ClO4-) anions affect the strength of the primary solvent coordination shells around Th4+ using explicit solvent and finite temperature ab initio molecular dynamics modeling methods. The 9-fold solvent geometry was found to be the most stable hydration structure in each aqueous solution. Relative to the dilute aqueous solution, the presence of the counter ions did not significantly alter the geometry of the primary hydration shell. However, the free energy analyses indicated that the 10-fold hydrated states were thermodynamically accessible in dilute and bromide aqueous solutions within 1 kcal/mol. Analysis of the results showed that the hydrogen bond lifetimes were longer and solvent exchange energy barriers were larger in solutions with counter ions in comparison with the solution with no counter ions. This implies that the presence of the counter ions induces a strengthening of the Th4+ hydration shell.

  1. A New Fluorescent Sensor for Transition Metal Ions in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new fluorescent sensor consisted of fluorenyl and dioxotetraaza unit, namely, 2,10-dimethyl-6-(9-fluorenyl)-1,4,8,11-tetraazaundencane-5,7-dione (L), was synthesized. It is a fluorescent sensor for transition metal ions in aqueous solution.

  2. Highly selective and sensitive fluorescent chemosensor for femtomolar detection of silver ion in aqueous medium

    Directory of Open Access Journals (Sweden)

    Abraham Daniel Arulraj

    2015-12-01

    Full Text Available The chemical sensing for the trace level detection of silver ion in aqueous solution still remains a challenge using simple, rapid, and inexpensive method. We report that thionine can be used as a fluorescent probe for the detection of Ag+ ion. The successive addition of Ag+ ion to the solution containing thionine quenches (turns-off the fluorescence intensity of thionine. Association and quenching constants have been estimated by the Benesi–Hildebrand method and Stern–Volmer plot, respectively. From the plot, the nature of the fluorescence quenching was confirmed as static quenching. An important feature of our chemosensor is high selectivity towards the determination of silver ion in aqueous solution over the other competitive metal ions. The detection limit of the sensor achieved 5 fM for Ag+ ion, which is superior to all previously reported chemosensors. The NMR and FT-IR studies were also carried out to support the complex formation between thionine and Ag+ ion. The practicality of the proposed chemosensor for determination of Ag+ ion was carried in untreated water samples.

  3. Thermodynamics and kinetics of ion speciation in supercritical aqueous solutions: A molecular based study

    Energy Technology Data Exchange (ETDEWEB)

    Chialvo, A.A.; Cummings, P.T. [Tennessee Univ., Knoxville, TN (United States). Dept. of Chemical Engineering]|[Oak Ridge National Lab., TN (United States); Simonson, J.M.; Mesmer, R.E. [Oak Ridge National Lab., TN (United States)

    1997-05-01

    Molecular simulation of infinitely dilute NaCl aqueous solutions are performed to study the Na{sup +}/Cl{sup -} ion pairing in a polarizable and a nonpolarizable solvent at supercritical conditions. The Simple Point Charge, Pettitt-Rossky, and Fumi-Tosi models for the water-water, ion-water, and ion-ion interactions are used in determining the degree of dissociation, its temperature and density dependence, and the kinetics of the interconversion between ion-pair configurations in a nonpolarizable medium. To assess the effect of the solvent polarizability on the stability of the ion-pair configurations, we replace the Simple Point Charge by the Polarizable Point Charge water model and determine the anion-cation potential of mean force at T{sub r}=1.20 and {rho}{sub r}=1.5.

  4. Ion spatial distributions at the liquid-vapor interface of aqueous potassium fluoride solutions.

    Science.gov (United States)

    Brown, Matthew A; D'Auria, Raffaella; Kuo, I-F William; Krisch, Maria J; Starr, David E; Bluhm, Hendrik; Tobias, Douglas J; Hemminger, John C

    2008-08-28

    X-Ray photoemission spectroscopy operating under ambient pressure conditions is used to probe ion distributions throughout the interfacial region of a free-flowing aqueous liquid micro-jet of 6 M potassium fluoride. Varying the energy of the ejected photoelectrons by carrying out experiments as a function of X-ray wavelength measures the composition of the aqueous-vapor interfacial region at various depths. The F(-) to K(+) atomic ratio is equal to unity throughout the interfacial region to a depth of 2 nm. The experimental ion profiles are compared with the results of a classical molecular dynamics simulation of a 6 M aqueous KF solution employing polarizable potentials. The experimental results are in qualitative agreement with the simulations when integrated over an exponentially decaying probe depth characteristic of an APPES experiment. First principles molecular dynamics simulations have been used to calculate the potential of mean force for moving a fluoride anion across the air-water interface. The results show that the fluoride anion is repelled from the interface, consistent with the depletion of F(-) at the interface revealed by the APPES experiment and polarizable force field-based molecular dynamics simulation. Together, the APPES and MD simulation data provide a detailed description of the aqueous-vapor interface of alkali fluoride systems. This work offers the first direct observation of the ion distribution at an aqueous potassium fluoride solution interface. The current experimental results are compared to those previously obtained for saturated solutions of KBr and KI to underscore the strong difference in surface propensity between soft/large and hard/small halide ions in aqueous solution.

  5. Ion-Mediated Gelation of Aqueous Suspensions of Cellulose Nanocrystals.

    Science.gov (United States)

    Chau, Mokit; Sriskandha, Shivanthi E; Pichugin, Dmitry; Thérien-Aubin, Héloïse; Nykypanchuk, Dmitro; Chauve, Grégory; Méthot, Myriam; Bouchard, Jean; Gang, Oleg; Kumacheva, Eugenia

    2015-08-10

    Nanofibrillar hydrogels are an important class of biomaterials with applications as catalytic scaffolds, artificial extracellular matrixes, coatings, and drug delivery materials. In the present work, we report the results of a comprehensive study of nanofibrillar hydrogels formed by cellulose nanocrystals (CNCs) in the presence of cations with various charge numbers and ionic radii. We examined sol-gel transitions in aqueous CNC suspensions and the rheological and structural properties of the CNC hydrogels. At a particular CNC concentration, with increasing charge and cation size, the dynamic shear moduli and mesh size in the hydrogel increased. These effects were ascribed to a stronger propensity of CNCs for side-by-side association. The resulting hydrogels had an isotropic nanofibrillar structure. A combination of complementary techniques offered insight into structure-property relationships of CNC hydrogels, which are important for their potential applications.

  6. Mechanisms of Ions Adsorption by Nanodiamonds in Aqueous Suspensions

    Directory of Open Access Journals (Sweden)

    K.A. Laptinskiy

    2013-12-01

    Full Text Available This work is devoted to the study of adsorption properties and adsorption mechanisms of the original (I6, modified (I6COOH nanodiamonds and charcoal dispersed in water, with respect to dissolved ions (Cu2 +, Pb2 +, NO3 –, CH3COO – using optical spectroscopy methods: Raman and IR spectroscopies, absorption, dynamic light scattering. Mechanisms of anions and cations adsorption were studied.

  7. Porous Methyltrimethoxysilane Coated Nanoscale-Hydroxyapatite for Removing Lead Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    C. S. Ciobanu

    2014-01-01

    Full Text Available The aim of this study was to synthetize new porous nanoparticles based on methyltrimethoxysilane coated hydroxyapatite (MTHAp for lead removal form aqueous solutions. The morphological and compositional analysis of MTHAp were investigated by X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM equipped with an energy dispersive X-ray spectrometer (EDS. Removal experiments of Pb2+ ions were carried out in aqueous solutions with controlled concentration of Pb2+ at a fixed pH value of 3 and 5 respectively. After the removal experiment of Pb2+ ions from solutions, porous hydroxyapatite nanoparticles were transformed into PbMTHAp_3 and PbMTHAp_5 via the adsorption of Pb2+ ions followed by a cation exchange reaction. The X-ray diffraction spectra of PbMTHAp_3 and PbMTHAp_5 revealed that the powders, after removal of the Pb2+ ions, were a mixture of Ca2.5Pb7.5(PO46(OH2, Pb2Ca4(PO42(SiO4, and Ca10(PO46(OH2. Our results demonstrate that the porous hydroxyapatite nanoparticles can be used as an adsorbent for removing Pb2+ ions from aqueous solutions.

  8. Fast heavy-ion radiation damage of glycine in aqueous solution

    Science.gov (United States)

    Nomura, Shinji; Tsuchida, Hidetsugu; Furuya, Ryosuke; Majima, Takuya; Itoh, Akio

    2016-12-01

    Fast heavy-ion radiolysis of biomolecules in aqueous solution is investigated for an atomistic understanding of radiation damage to normal cells during heavy-particle beam therapy. The smallest amino acid glycine was used as a model biomaterial. Microjets of aqueous glycine solutions under vacuum were irradiated with 4.0-MeV carbon ions corresponding to energies in the Bragg peak region. To understand the effects of the water environment on molecular damage, the yield of glycine dissociation was measured by secondary ion mass spectroscopy. The yield was significantly reduced relative to gas-phase glycine targets. This implies that the numerous water molecules surrounding a single glycine molecule act as a buffer that suppresses dissociation. This is an environmental effect similar to that observed for other biomolecular cluster targets.

  9. Sono-electrochemical recovery of metal ions from their aqueous solutions.

    Science.gov (United States)

    Dong, Bingfeng; Fishgold, Asher; Lee, Paul; Runge, Keith; Deymier, Pierre; Keswani, Manish

    2016-11-15

    Metal recovery from aqueous waste streams is an important goal for recycling, agriculture and mining industries. The development of more effective methods of recovery have been of increasing interest. The most common methods for metal recovery include precipitation, electrochemical, ion exchange, flocculation/coagulation and filtration. In the current work, a sono-electrochemical technique employing sound field at megasonic frequency (500kHz or 1MHz) in conjunction with electrochemistry is evaluated for enhanced recovery of selected metal ions (palladium, lead and gallium) with different redox potentials from their aqueous solutions. The surface morphology and elemental composition of the metal deposits were characterized using scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The percent recovery was found to depend on the type of metal ion and the megasonic frequency used. Palladium was recovered in its metal form, while lead and gallium were oxidized during or after the recovery process.

  10. CSNS H- ion source test stand

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-Bing; ZHANG Jun-Song; ZHANG Hua-Shun; ZHAO Fu-Xiang; OUYANG Hua-Fu; CHI Yun-Long; HE Wei; HUANG Tao; LI Gang; LIU Ying-Man; LU Yan-Hua; XU Tao-Guang

    2011-01-01

    The Penning surface plasma source is adopted as the China Spallation Neutron Source (CSNS) H- ion source. The designed energy and beam current of the source are 50 keV and 20 mA, respectively, with a normalized root mean square(norm·rms.)emittance of 0.2πmm·mrad.The construction of a H-ion source test stand has been completed, and the commissioning of the source is in progress. Stable H- ion beams with energy of 50 keV and current up to 50 mA are attained. Emittance measurement for the H- beam is being prepared.

  11. [Removal of Sulfate Ions from Aqueous Solution by Adsorption with Hydrotalcite- like Composite].

    Science.gov (United States)

    Gu, Yi-bing; Ma, Yong-wen; Wan, Jin-quan; Wang, Yan; Guan, Ze-yu

    2016-03-15

    Hydrotalcite-like composite synthesized by co-precipitation method was used as an adsorbent to remove the sulfate ions in aqueous solution. XRD, FT-IR , SEM and EDS elemental analysis were used to clarify the structure and composition of the hydrotalcite- like composite. The influences of time, initial pH value and coexisting ions on adsorption performance were investigated. The result showed the material was the composite of zinc aluminum nitrate hydrotalcite-like compounds and zinc aluminum phenylalanine hydrotalcite-like compounds. Hydrotalcite-like composite had a good performance in adsorption of sulfate ions, and the maximum adsorption capacity was 52.75 mg · g⁻¹. The data fitted pseudo-second order kinetic model best, which indicated that chemical adsorption was the rate-limiting step. Freundlich isotherm was more suitable to describe the adsorption process, and this meant the adsorption of sulfate ions by hydrotalcite-like composite was multilayered adsorption. Thermodynamic parameters showed that the adsorption process was endothermic and spontaneous at room temperature. Hydrotalcite-like composite adsorbed sulfate ions mainly through ion exchange, electrostatic force and physical adsorption. The experimental results showed that the hydrotalcite-like composite had potential for sulfate ion removal in the aqueous solution.

  12. Non-aqueous electrolyte for lithium-ion battery

    Energy Technology Data Exchange (ETDEWEB)

    Amine, Khalil; Zhang, Lu; Zhang, Zhengcheng

    2016-01-26

    A substantially non-aqueous electrolyte solution includes an alkali metal salt, a polar aprotic solvent, and an organophosphorus compound of Formula IA, IB, or IC: ##STR00001## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are each independently hydrogen, halogen, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, heteroaryl, alkoxy, alkenoxy, alkynoxy, cycloalkoxy, aryloxy, heterocyclyloxy, heteroaryloxy, siloxyl, silyl, or organophosphatyl; R.sup.5 and R.sup.6 are each independently alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocyclyl, or heteroaryl; R.sup.7 is ##STR00002## and R.sup.8, R.sup.9 and R.sup.10 are each independently alkyl, cycloalkyl, aryl, heterocyclyl, or heteroaryl; provided that if the organophosphorus compound is of Formula IB, then at least one of R.sup.5, and R.sup.6 are other than hydrogen, alkyl, or alkenyl; and if the organophosphorus compound is of Formula IC, then the electrolyte solution does not include 4-methylene-1,3-dioxolan-2-one or 4,5-dimethylene-1,3-dioxolan-2-one.

  13. Removal of Cadmium and Lead Ions from Aqueous Solution by Nanocrystalline Magnetite Through Mechanochemical Activation

    Directory of Open Access Journals (Sweden)

    Mohsen Hosseinzadeh

    2016-12-01

    Full Text Available In this study, the removal of cadmium and lead ions from aqueous solution by nanocrystalline magnetite was investigated. The nanocrystalline magnetite was synthesized by mechanochemical activation of hematite in a high energy planetary mill in argon atmosphere for 45 hours. The ability of the synthesized nanocrystalline magnetite for removal of Cd(II and Pb(II from aqueous solutions was studied in a batch reactor under different experimental conditions with different pHs, contact times, initial metal ion concentrations and temperatures. The solution’s pH was found to be a key factor in the adsorption of heavy metal ions on Fe3O4. The optimum pH of the solution for adsorption of Cd(II and Pb(II from aqueous solutions was found to be 6.5 and 5.5, respectively. The best models to describe the kinetics and isotherms of single adsorption were both the pseudo first and second-order kinetic models and Langmuir models, respectively, indicating the monolayer chemisorption of Cd(II and Pb(II on Fe3O4 nanoparticles. Moreover, the thermodynamic parameters (i.e., ∆H°, ∆S°, ∆G° were evaluated which indicated that the adsorption was spontaneous and exothermic. The results suggested that the synthesized material (magnetite nanocrystalline particles may be used as effective and economic absorbent for removal of Cd(II and Pb(II from aqueous solutions.

  14. Ion-specific thermodynamical properties of aqueous proteins

    Directory of Open Access Journals (Sweden)

    Eduardo R.A. Lima

    2010-03-01

    Full Text Available Ion-specific interactions between two colloidal particles are calculated using a modified Poisson-Boltzmann (PBequationandMonteCarlo(MCsimulations. PBequationspresentgoodresultsofionicconcentration profiles around a macroion, especially for salt solutions containing monovalent ions. These equations include not only electrostatic interactions, but also dispersion potentials originated from polarizabilities of ions and proteins. This enables us to predict ion-specific properties of colloidal systems. We compared results obtained from the modified PB equation with those from MC simulations and integral equations. Phase diagrams and osmotic second virial coefficients are also presented for different salt solutions at different pH and ionic strengths, in agreement with the experimental results observed Hofmeister effects. In order to include the water structure and hydration effect, we have used an effective interaction obtained from molecular dynamics of each ion and a hydrophobic surface combined with PB equation. The method has been proved to be efficient and suitable for describing phenomena where the water structure close to the interface plays an essential role. Important thermodynamic properties related to protein aggregation, essential in biotechnology and pharmaceutical industries, can be obtained from the method shown here.Interações íon-específicas (dependentes do tipo de íon presente em solução entre duas partículas coloidais são calculadas usando a equação de Poisson-Boltzmann (PB modificada e simulações de Monte Carlo (MC. As equações de PB apresentam bons resultados de perfis de concentração nas proximidades de um macro-íon, principalmente para soluções salinas contendo íons monovalentes. Estas equações incluem não só interações eletrostáticas, mas também potenciais de dispersão, que têm origem nas polarizabilidades de íons e proteínas, permitindo a predição de propriedades íon-específicas de

  15. Structure, hydrolysis, and diffusion of aqueous vanadium ions from Car-Parrinello molecular dynamics

    Science.gov (United States)

    Jiang, Zhen; Klyukin, Konstantin; Alexandrov, Vitaly

    2016-09-01

    A molecular level understanding of the properties of electroactive vanadium species in aqueous solution is crucial for enhancing the performance of vanadium redox flow batteries. Here, we employ Car-Parrinello molecular dynamics simulations based on density functional theory to investigate the hydration structures, first hydrolysis reaction, and diffusion of aqueous V2+, V3+, VO2+, and VO 2+ ions at 300 K. The results indicate that the first hydration shell of both V2+ and V3+ contains six water molecules, while VO2+ is coordinated to five and VO 2+ to three water ligands. The first acidity constants (pKa) estimated using metadynamics simulations are 2.47, 3.06, and 5.38 for aqueous V3+, VO 2+ , and VO2+, respectively, while V2+ is predicted to be a fairly weak acid in aqueous solution with a pKa value of 6.22. We also show that the presence of chloride ions in the first coordination sphere of the aqueous VO 2+ ion has a significant impact on water hydrolysis leading to a much higher pKa value of 4.8. This should result in a lower propensity of aqueous VO 2+ for oxide precipitation reaction in agreement with experimental observations for chloride-based electrolyte solutions. The computed diffusion coefficients of vanadium species in water at room temperature are found to increase as V 3 + < VO 2 + < V O 2 + < V 2 + and thus correlate with the simulated hydrolysis constants, namely, the higher the pKa value, the greater the diffusion coefficient.

  16. Efficiency of Chitosan for the Removal of Pb (II, Fe (II and Cu (II Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Soheil Sobhanardakani

    2014-09-01

    Full Text Available Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II, Fe(II and Cu(II ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II, Fe(II and Cu(II from aqueous solution. In batch tests, the effects of parameters like pH solution (1.0-8.0, initial metal concentrations (100-1000 mgL-1, contact time (5.0-150 min and adsorbent dose (1.0-7.0 g on the adsorption process were studied. Results: The results showed that the adsorption of Pb(II, Fe(II and Cu(II ions on chitosan strongly depends on pH. The experimental isothermal data were analyzed using the Langmuir and Freundlich equations and it was found that the removal process followed the Langmuir isotherm and maximum adsorption capacity for the adsorption of Pb(II, Fe(II and Cu(II ions by the chitosan were 55.5mg g−1, 71.4 mg g−1 and 59 mg g−1, respectively, under equilibrium conditions at 25±1 ºC. The adsorption process was found to be well described by the pseudo-second-order rate model. Conclusion: The obtained results showed that chitosan is a readily, available, economic adsorbent and was found suitable for removing Pb(II, Fe(II and Cu(II ions from aqueous solution.

  17. Ion-binding of glycine zwitterion with inorganic ions in biologically relevant aqueous electrolyte solutions.

    Science.gov (United States)

    Fedotova, Marina V; Kruchinin, Sergey E

    2014-06-01

    The ion-binding between inorganic ions and charged functional groups of glycine zwitter-ion in NaCl(aq), KCl(aq), MgCl2(aq), and CaCl2(aq) has been investigated over a wide salt concentration range by using integral equation theory in the 3D-RISM approach. These systems mimic biological systems where binding of ions to charged residues at protein surfaces is relevant. It has been found that the stability of ion pairs formed by the carboxylate group and added inorganic cations decreases in the sequence Mg(2+)>Ca(2+)>Na(+)>K(+). However, all formed ion pairs are weak and decrease in stability with increasing salt concentration. On the other hand, at a given salt concentration the stability of (-NH3(+):Cl(-))aq ion pairs is similar in all studied systems. The features of ion-binding and the salt concentration effect on this process are discussed.

  18. "Super" Cocktails for Heavy Ion Testing

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Michael B; Johnson, Michael B.; McMahan, Margaret A.; Galloway, Michelle; Leitner, Daniela; Morel, James R.; Gimpel, ThomasL.; Ninemire, Brien F.; Siero, Reba; Thatcher, Raymond K.

    2007-07-21

    The 4.5 MeV/nucleon heavy ion cocktail at the 88-Inch Cyclotron has been expanded by incorporating beams from solid material to fill in the linear energy transfer curve. This supercocktail is available by special request and is useful when only normal incidence between the beam and the device under test is possible or desirable.

  19. Water rotational jump driven large amplitude molecular motions of nitrate ions in aqueous potassium nitrate solution

    CERN Document Server

    Banerjee, Puja; Bagchi, Biman

    2016-01-01

    Molecular dynamics simulations of aqueous potassium nitrate solution reveal a highly complex rotational dynamics of nitrate ions where, superimposed on the expected continuous Brownian motion, are large amplitude angular jumps that are coupled to and at least partly driven by similar large amplitude jump motions in water molecules which are associated with change in the hydrogen bonded water molecule. These jumps contribute significantly to rotational and translational motions of these ions. We explore the detailed mechanism of these correlated (or, coupled) jumps and introduce a new time correlation function to decompose the coupled orientational- jump dynamics of solvent and solute in the aqueous electrolytic solution. Time correlation function provides for the unequivocal determination of the time constant involved in orientational dynamics originating from making and breaking of hydrogen bonds. We discover two distinct mechanisms-both are coupled to density fluctuation but are of different types.

  20. Ion Exchange Extraction of Boron from Aqueous Fluids by Amberlite IRA 743 Resin

    Institute of Scientific and Technical Information of China (English)

    肖应凯; 廖步勇; 刘卫国; 肖云; SWIHART,GeorgeH.

    2003-01-01

    The ion exchange characteristics d Amherlite IRA 743 resin for extracting boron from aqueous fluids have been investigated in detail. The results show that AmherHte IRA 743 resin, a boron specific ion exchange resin, can quantitatively extract boron as the B (OH)4- spedes from weakly basle solution. Some exchangeable anions such as CI- and SO42- are present, resulting in an increase in pH value of the loeded solution within the nan, and the boron in natural aqueous fluids with low nH is also extracted by Amberlite IRA 743 resin. However, the voiume of loaded solution must be restricted. The maximum voiume of loaded solution giving quantitative extraction of boron decreases for sample soh.,tiom of lower pH value. Warm HCI solution is more effective than room temperature HCI solution for eluting boron from Amberllte IRA 743 resin.

  1. Synthesis and Electrochemical Performance of a Lithium Titanium Phosphate Anode for Aqueous Lithium-Ion Batteries

    KAUST Repository

    Wessells, Colin

    2011-01-01

    Lithium-ion batteries that use aqueous electrolytes offer safety and cost advantages when compared to today\\'s commercial cells that use organic electrolytes. The equilibrium reaction potential of lithium titanium phosphate is -0.5 V with respect to the standard hydrogen electrode, which makes this material attractive for use as a negative electrode in aqueous electrolytes. This material was synthesized using a Pechini type method. Galvanostatic cycling of the resulting lithium titanium phosphate showed an initial discharge capacity of 115 mAh/g and quite good capacity retention during cycling, 84% after 100 cycles, and 70% after 160 cycles at a 1 C cycling rate in an organic electrolyte. An initial discharge capacity of 113 mAh/g and capacity retention of 89% after 100 cycles with a coulombic efficiency above 98% was observed at a C/5 rate in pH -neutral 2 M Li2 S O4. The good cycle life and high efficiency in an aqueous electrolyte demonstrate that lithium titanium phosphate is an excellent candidate negative electrode material for use in aqueous lithium-ion batteries. © 2011 The Electrochemical Society.

  2. Study on the adsorption of heavy metal ions from aqueous solution on modified SBA-15

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2013-01-01

    Full Text Available Amino-functionalized SBA-15 mesoporous silica was prepared, characterized, and used as an adsorbent for heavy metal ions. The organic - inorganic hybrid material was obtained by a grafting procedure using SBA-15 silica with 3-aminopropyl-triethoxysilane and bis(2,4,4-trimethylpentyl phosphinic acid (Cyanex 272, respectively. The structure and physicochemical properties of the materials were characterized by means of elemental analysis, X-ray diffraction (XRD, nitrogen adsorption - desorption, thermogravimetric analysis, FTIR spectroscopy and immersion calorimetry. The organic functional groups were successfully grafted onto the SBA-15 surface and the ordering of the support was not affected by the chemical modification. The behavior of the grafted solids was investigated for the adsorption of heavy metal ions from aqueous solutions. The hybrid materials showed high adsorption capacity and high selectivity for zinc ions. Other ions, such as cooper and cobalt were absorbed by the modified SBA-15 material.

  3. [Investigation of the oxidation reaction of O3 with bromide ion in aqueous solution].

    Science.gov (United States)

    Yu, Xiao-Ting; Zhang, Jia-Hui; Pan, Xun-Xi; Zhang, Ren-Xi; Hou, Hui-Qi

    2012-09-01

    The reaction mechanism of O3 with bromide ion in aqueous solution was studied by ion chromatography and UV-Vis spectrometry instruments. Ion chromatography analysis showed that only 10% of Br- which was oxidized by ozone was formed into bromate ion. The results demonstrated that the final products of the oxidation reaction were identified as Br2 and Br3- except for BrO3-. The formation of Br3- which was yielded from the reaction of Br2 with Br- was the major process in the reaction of Br attacked by O3. The characteristic absorption spectrum of Br3- with an absorption peak at 260 nm was also investigated. The results may provide helpful information about the mechanism of the oxidation reaction of Br- with O3 and fate of Br- or its derivatives in the environment by the oxidation processes.

  4. Ion Pair in Extreme Aqueous Environments, Molecular-Based and Electric Conductance Approaches

    Energy Technology Data Exchange (ETDEWEB)

    Chialvo, Ariel A [ORNL; Gruszkiewicz, Miroslaw {Mirek} S [ORNL; Simonson, J Michael {Mike} [ORNL; Palmer, Donald [ORNL; Cole, David R [ORNL

    2009-01-01

    We determine by molecular-based simulation the density profiles of the Na+!Cl! ion-pair association constant in steam environments along three supercritical isotherms to interrogate the behavior of ion speciation in dilute aqueous solutions at extreme conditions. Moreover, we describe a new ultra-sensitive flow-through electric conductance apparatus designed to bridge the gap between the currently lowest steam-density conditions at which we are experimentally able to attain electric conductance measurements and the theoretically-reachable zero-density limit. Finally, we highlight important modeling challenges encountered near the zero-density limit and discuss ways to overcome them.

  5. Poisson-Fermi model of single ion activities in aqueous solutions

    Science.gov (United States)

    Liu, Jinn-Liang; Eisenberg, Bob

    2015-09-01

    A Poisson-Fermi model is proposed for calculating activity coefficients of single ions in strong electrolyte solutions based on the experimental Born radii and hydration shells of ions in aqueous solutions. The steric effect of water molecules and interstitial voids in the first and second hydration shells play an important role in our model. The screening and polarization effects of water are also included in the model that can thus describe spatial variations of dielectric permittivity, water density, void volume, and ionic concentration. The activity coefficients obtained by the Poisson-Fermi model with only one adjustable parameter are shown to agree with experimental data, which vary nonmonotonically with salt concentrations.

  6. Biosorption of heavy metal ions from aqueous solutions by short hemp fibers: Effect of chemical composition.

    Science.gov (United States)

    Pejic, Biljana; Vukcevic, Marija; Kostic, Mirjana; Skundric, Petar

    2009-05-15

    Sorption potential of waste short hemp fibers for Pb(2+), Cd(2+) and Zn(2+) ions from aqueous media was explored. In order to assess the influence of hemp fiber chemical composition on their heavy metals sorption potential, lignin and hemicelluloses were removed selectively by chemical modification. The degree of fiber swelling and water retention value were determined in order to evaluate the change in accessibility of the cell wall components to aqueous solutions due to the fiber modification. The effects of initial ion concentration, contact time and cosorption were studied in batch sorption experiments. The obtained results show that when the content of either lignin or hemicelluloses is progressively reduced by chemical treatment, the sorption properties of hemp fibers are improved. Short hemp fibers are capable of sorbing metal ions (Pb(2+), Cd(2+) and Zn(2+)) from single as well as from ternary metal ion solutions. The maximum total uptake capacities for Pb(2+), Cd(2+) and Zn(2+) ions from single solutions are the same, i.e. 0.078mmol/g, and from ternary mixture 0.074, 0.035 and 0.035mmol/g, respectively.

  7. Experimental Study on Surface Reactions of Heavy Metal Ions With Quartz—Aqueous Ion Concentration Dependence

    Institute of Scientific and Technical Information of China (English)

    吴宏海; 吴大清; 等

    1999-01-01

    Adsorption of divalent metal ions,including Cu2+,Pb2+,Zn2+,Cd2+ and Ni2+,on quartz surface was measured as a function of metal ion concentration at 30℃under condi tions of solution pH=6.5 and ion strength I=0.1mol/L.Results of the experimental measuements can be described very well by adsorption isoterm dquations of Freudlich.The correlation coefficients(r)of adsorption isotherm lines are>0.96.Moreover,the exprimental data were interpreted on the basis of surface complexation model.Te experimental results showed that the monodentate-coordinated metal ion surface complex species(SOM+)are predominant over the bidentate-coordinated metal ion surface complex species[(SO)2M]formed only by the ions Cu2+,Zn2+ and Ni2+,And the relevant apparent surface complexation constants are lgKM=2.2-3.3 in order of KCd≥KPb>KZn>KNi≥KCu,and lgβM=5.8-6.8 in oder of βNi>βZn>βCu.Therefore,the reactive ability of the ions onto mineral surface of quartz follows the order of Cd>Pb>Zn>Ni>Cu under the above-mentioned solution conditions.The apparent surface complexation constants,influenced by the surface potential,surface species and hydrolysis of metal ions,depend mainly on the Born solvation coefficeient of the metal ions.

  8. Sorption of Ni(II) ions from aqueous solution by Lewatit cation-exchange resin.

    Science.gov (United States)

    Dizge, Nadir; Keskinler, Bülent; Barlas, Hulusi

    2009-08-15

    Ion-exchange is an alternative process for uptake of heavy metals from aqueous solutions. In the present study, the sorption of nickel(II) ions from aqueous solution was investigated by using Lewatit MonoPlus SP 112 (strongly acidic, macroporous cation-exchange resin) in a batch adsorption system as a function of pH (2.0-8.0), initial nickel concentration (50-200 mg/L), resin dosage (0.5-2.0 g/L), contact time (0.5-3h), and temperatures (298-318K). The data were analyzed on the basis of Lagergren pseudo-first order, pseudo-second order (Types 1-5), Elovich and external, Weber-Morris intraparticle, pore-surface mass diffusion models. The experimental data showed that the maximum pH for efficient sorption of nickel(II) was 6.0. At the optimal conditions, nickel(II) ions sorption on the resin was decreased when the initial metal concentration increased. The results indicated that the resin dosage strongly affected the amount of nickel(II) ions removed from aqueous solution. The adsorption process was very fast due to 80% of nickel(II) sorption was occurred within 30 min and equilibrium was reached at about 90 min. Freundlich and Langmuir adsorption isotherm models were used for sorption equilibrium data and the maximum adsorption capacity (171 mg/g) of Lewatit MonoPlus SP 112 was obtained from Langmuir isotherm. The thermodynamic parameters (DeltaG degrees, free energy change; DeltaS degrees, enthalpy change; and DeltaH degrees, entropy change) for sorption of nickel(II) ions were evaluated. The rise in temperature caused a partly increase in the value of the equilibrium constant (K(c)) for the sorption of nickel(II) ions. Moreover, column flow adsorption study was also studied. Breakthrough curves were obtained from column flow studies by using both synthetic solution and rinsing bath water of filter industry. The column regeneration was carried out for two sorption-desorption cycles. The eluant used for regeneration of the cation-exchange resin was 7% (w/w) HCl. The

  9. [Effect of inorganic ions on degradation of trace nitrobenzene in aqueous solution by catalytic ozonation].

    Science.gov (United States)

    Zhao, Lei; Ma, Jun; Sun, Zhi-zhong

    2006-05-01

    The experiment investigated the effects of general inorganic ions in natural source water on the three processes of ozonation alone, ceramic honeycomb and modified ceramic honeycomb-catalyzed ozonation for degradation of trace nitrobenzene in aqueous solution. The removal rate of ozonation alone and modified ceramic honeycomb-catalyzed ozonation increased by 5.0% and 8.6% with the increase of the concentration of calcium ion (0-4 mg x L(-1)), and that of ceramic honeycomb-catalyzed ozonation reached the climax at the concentration of calcium ion 0.5 mg x L(-1) under the same experimental condition. The degradation efficiency of ozonation alone, ceramic honeycomb and modified ceramic honeycomb-catalyzed ozonation enhanced by 10.9%, 11.6% and 9.6% with the increase of the concentration of manganese ion (0-4 mg x L(-1)), respectively, and decreased by 8.6%, 11.5% and 8.9% with the increase of the concentration of bicarbonate ion (0-200 mg x L(-1)). The concentration of nitrate and sulfate ion had no remarkable effect on ozonation alone, but the removal rate of other two processes decreased with the increase of the concentration of nitrate and sulfate ion.

  10. Characterization of aqueous silver nitrate solutions for leakage tests

    Directory of Open Access Journals (Sweden)

    José Ferreira Costa

    2011-06-01

    Full Text Available OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled and three brands of silver nitrate salt (Merck, Synth or Cennabras at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h and concentrations (1, 5, 25, 50% of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%. RESULTS: The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9. Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm. In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000. CONCLUSIONS: Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were

  11. Characterization of aqueous silver nitrate solutions for leakage tests

    Science.gov (United States)

    COSTA, José Ferreira; SIQUEIRA, Walter Luiz; LOGUERCIO, Alessandro Dourado; REIS, Alessandra; de OLIVEIRA, Elizabeth; ALVES, Cláudia Maria Coelho; BAUER, José Roberto de Oliveira; GRANDE, Rosa Helena Miranda

    2011-01-01

    Objectives To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. Material and Methods A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silver nitrate salt (Merck, Synth or Cennabras) at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h) and concentrations (1, 5, 25, 50%) of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%). Results The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9). Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm). In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000). Conclusions Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were capable of

  12. Removal of Cu 2+ Ions from Aqueous Medium Using Clinoptilolite/Emeraldine Base Composite

    Directory of Open Access Journals (Sweden)

    Silviya I. Lavrova

    2016-12-01

    Full Text Available The aim of this study was to investigate the removal efficiency of in situ synthesized composites consisted of emeraldine base and clinoptilolite on copper ions removal from aqueous medium. Two composite materials (Composite I and Composite II with different quantity of clinoptilolite were synthesised. The influence of the composite dosage, the contact time and the initial copper ions concentration has been studied. The results show that the significant removal of the copper ions becomes at the first minute of the contact between the composite material and the aqueous medium and the longer contact time leads to increasing of the copper ions removal. The removal efficiency at the 1st minute was 57.5% and 77.3% using Composite Iand Composite II, respectively. Maximum removal efficiency of 87.3% and 96.8% was achieved at the same dosage of Composite I and Composite II, respectively, at contact time of 360 minutes and temperature of 24 °C.

  13. Air, aqueous and thermal stabilities of Ce3+ ions in cerium oxide nanoparticle layers with substrates

    KAUST Repository

    Naganuma, Tamaki

    2014-01-01

    Abundant oxygen vacancies coexisting with Ce3+ ions in fluorite cerium oxide nanoparticles (CNPs) have the potential to enhance catalytic ability, but the ratio of unstable Ce3+ ions in CNPs is typically low. Our recent work, however, demonstrated that the abundant Ce3+ ions created in cerium oxide nanoparticle layers (CNPLs) by Ar ion irradiation were stable in air at room temperature. Ce valence states in CNPs correlate with the catalytic ability that involves redox reactions between Ce3+ and Ce4+ ions in given application environments (e.g. high temperature in carbon monoxide gas conversion and immersion conditions in biomedical applications). To better understand the mechanism by which Ce3+ ions achieve stability in CNPLs, we examined (i) extra-long air-stability, (ii) thermal stability up to 500 °C, and (iii) aqueous stability of Ce 3+ ions in water, buffer solution and cell culture medium. It is noteworthy that air-stability of Ce3+ ions in CNPLs persisted for more than 1 year. Thermal stability results showed that oxidation of Ce 3+ to Ce4+ occurred at 350 °C in air. Highly concentrated Ce3+ ions in ultra-thin CNPLs slowly oxidized in water within 1 day, but stability was improved in the cell culture medium. Ce 3+ stability of CNPLs immersed in the medium was associated with phosphorus adsorption on the Ce3+ sites. This study also illuminates the potential interaction mechanisms of stable Ce3+ ions in CNPLs. These findings could be utilized to understand catalytic mechanisms of CNPs with abundant oxygen vacancies in their application environments. © The Royal Society of Chemistry 2014.

  14. Charge dependence of solvent-mediated intermolecular Coster-Kronig decay dynamics of aqueous ions.

    Science.gov (United States)

    Ohrwall, G; Ottosson, N; Pokapanich, W; Legendre, S; Svensson, S; Björneholm, O

    2010-12-30

    The 2s and 2p photoelectron spectra have been measured for Na(+), Mg(2+), and Al(3+) ions in aqueous solution. In all cases, the 2s lines are significantly broader than the 2p features, which is attributed to a shorter lifetime of the respective 2s hole. Since intraionic Coster-Kronig decay channels from the (2s)(-1) state are closed for free Na(+), Mg(2+), and Al(3+) ions, this is evidence for an intermolecular Coster-Kronig-like process, reminiscent of intermolecular Coulombic decay (ICD), involving neighboring water solvent molecules. The observed 2s Lorentzian line widths correspond to lifetimes of the (2s)(-1) state of 3.1, 1.5, and 0.98 fs for the solvated Na, Mg, and Al ions, respectively.

  15. Removal of Lead (II Ions from Aqueous Solutions onto Activated Carbon Derived from Waste Biomass

    Directory of Open Access Journals (Sweden)

    Murat Erdem

    2013-01-01

    Full Text Available The removal of lead (II ions from aqueous solutions was carried out using an activated carbon prepared from a waste biomass. The effects of various parameters such as pH, contact time, initial concentration of lead (II ions, and temperature on the adsorption process were investigated. Energy Dispersive X-Ray Spectroscopy (EDS analysis after adsorption reveals the accumulation of lead (II ions onto activated carbon. The Langmuir and Freundlich isotherm models were applied to analyze equilibrium data. The maximum monolayer adsorption capacity of activated carbon was found to be 476.2 mg g−1. The kinetic data were evaluated and the pseudo-second-order equation provided the best correlation. Thermodynamic parameters suggest that the adsorption process is endothermic and spontaneous.

  16. Removal of phosphate ions from aqueous solution using Tunisian clays minerals and synthetic zeolite

    Institute of Scientific and Technical Information of China (English)

    Noureddine Hamdi; Ezzeddine Srasra

    2012-01-01

    Phosphate ions are usually considered to be responsible for the algal bloom in receiving water bodies and aesthetic problems in water.From the environmental point of view,the management of such contaminant and valuable resource is very important.The present work deals with the removal of phosphate ions from aqueous solutions using kaolinitic and smectic clay minerals and synthetic zeolite as adsorbent.The pH effect and adsorption kinetic were studied.It was found that phosphate could be efficiently removed at acidic pH (between 4 and 6) and the second order model of kinetics is more adopted for all samples.The isotherms of adsorption of phosphate ions by the two clays and the zeolite samples show that the zeolite has the highest rate of uptake (52.9 mg P/g).Equilibrium data were well fitted with Langmuir and Freundlich isotherm.

  17. Electrochemical behavior of LiCoO2 as aqueous lithium-ion battery electrodes

    KAUST Repository

    Ruffo, Riccardo

    2009-02-01

    Despite the large number of studies on the behavior of LiCoO2 in organic electrolytes and its recent application as a positive electrode in rechargeable water battery prototypes, a little information is available about the lithium intercalation reaction in this layered compound in aqueous electrolytes. This work shows that LiCoO2 electrodes can be reversibly cycled in LiNO3 aqueous electrolytes for tens of cycles at remarkably high rates with impressive values specific capacity higher than 100 mAh/g, and with a coulomb efficiency greater than 99.7%. Stable and reproducible cycling measurements have been made using a simple cell design that can be easily applied to the study of other intercalation materials, assuming that they are stable in water and that their intercalation potential range matches the electrochemical stability window of the aqueous electrolyte. The experimental arrangement uses a three-electrode flooded cell in which another insertion compound acts as a reversible source and sink of lithium ions, i.e., as the counter electrode. A commercial reference electrode is also present. Both the working and the counter electrodes have been prepared as thin layers on a metallic substrate using the procedures typical for the study of electrodes for lithium-ion batteries in organic solvent electrolytes. © 2008 Elsevier B.V. All rights reserved.

  18. Adsorption of Heavy Metal Ions from Aqueous Solutions by Zeolite Based on Oil Shale Ash: Kinetic and Equilibrium Studies

    Institute of Scientific and Technical Information of China (English)

    BAO Wei-wei; ZOU Hai-feng; GAN Shu-cai; XU Xue-chun; JI Gui-juan; ZHENG Ke-yan

    2013-01-01

    Na-A zeolite was successfully synthesized via the alkaline fusion method with oil shale ash as the raw material.The adsorption capacity of it was tested by removing CU2+,Ni2+,Pb2+ and Cd2+ from aqueous solutions.The results reveal the maximum adsorption capacity of adsorbent for Pb2+,Cu2+,Cd2+ and Ni2+ were 224.72,156.74,118.34 and 53.02 mg/g,respectively.The effects of contact time and pH value of solutions on the adsorption efficiency of the zeolite were evaluated.Besides,The equilibrium adsorption data and the batch kinetic data were correlated with Langmuir and Freundlich models and the pseudo-first-order and pseudo-second-order models separately.The results show that the Langmuir isotherm and the pseudo-second-order equation were more suitable for the adsorption of Na-A zeolite for the metal ions.In addition,Thermodynamic parameters of the adsorption(the Gibbs free energy,entropy,and enthalpy) were also evaluated and discussed.The results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions and the synthesized zeolite was an effective adsorbent for the removal of metal ions from aqueous solution.

  19. Removal of Pb(II) ions from aqueous solutions on few-layered graphene oxide nanosheets.

    Science.gov (United States)

    Zhao, Guixia; Ren, Xuemei; Gao, Xing; Tan, Xiaoli; Li, Jiaxing; Chen, Changlun; Huang, Yuying; Wang, Xiangke

    2011-11-07

    Few-layered graphene oxide (FGO) was synthesized from graphite by using the modified Hummers method, and was characterized by scanning electron microscopy, atomic force microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. The prepared FGO was used to adsorb Pb(II) ions from aqueous solutions. The abundant oxygen-containing groups on the surfaces of FGO played an important role in Pb(II) ion adsorption on FGO. The adsorption of Pb(II) ions on FGO was dependent on pH values and independent of ionic strength. The adsorption of Pb(II) ions on FGO was mainly dominated by strong surface complexation. From the adsorption isotherms, the maximum adsorption capacities (C(smax)) of Pb(II) ions on FGO calculated from the Langmuir model were about 842, 1150, and 1850 mg g(-1) at 293, 313, and 333 K, respectively, higher than any currently reported. The FGO had the highest adsorption capacities of today's nanomaterials. The thermodynamic parameters calculated from the temperature dependent adsorption isotherms indicated that the adsorption of Pb(II) ions on FGO was a spontaneous and endothermic process.

  20. Determination of Trace Iodide in Sodium Bisulfite Aqueous Solution by Ion Chromatography with UV Detection

    Energy Technology Data Exchange (ETDEWEB)

    Park, Y.S.; Kim, D.Y.; Choi, K.S.; Park, S.D.; Han, S.H. [Korea Atomic Energy Research Institute, Taejon (Korea)

    2000-06-01

    The iodide was recovered from a simulated spent fuel to the sodium bisulfite aqueous solution. It was discussed that the trace iodide (below 1 ppm) was determined without the matrix effect of 0.1 M sodium bisulfite and 1 mM HNO{sub 3} in aqueous solution by ion chromatography with UV detection. AS4A-SC(DIONEX) column and UV-absorption spectrophotometer were used. The UV-absorption spectra of sodium bisulfite nitric acid and iodide were obtained, and then 230 nm was selected as an absorption wavelength for iodide determination. 0.1 M NaCl eluent was optimum condition. In this condition the calibration curve of iodide was obtained on the range of about 0-1,000 ppb. The linear coefficient was 0.99993 and the detection limit was 5 ppb. The relative standard deviation was 1.26%. (author). 17 refs., 3 tabs., 4 figs.

  1. Shellac-coated iron oxide nanoparticles for removal of cadmium(Ⅱ) ions from aqueous solution

    Institute of Scientific and Technical Information of China (English)

    Jilai Gong; Long Chen; Guangming Zeng; Fei Long; Jiuhua Deng; Qiuya Niu; Xun He

    2012-01-01

    This study describes a new effective adsorbent for cadmium removal from aqueous solution synthesized by coating a shellac layer,a natural biodegradable and renewable resin with abundant hydroxyl and carboxylic groups,on the surface of iron oxide magnetic nanoparticles.Transmission Electron Microscopy (TEM) imaging showed shellac-coated magnetic nanoparticle (SCMN) adsorbents had a core-shell structure with a core of 20 nm and shell of 5 nm.Fourier Transform Infrared Spectroscopic analysis suggested the occurrence of reaction between carboxyl groups on the SCMN adsorbent surface and cadmium ions in aqueous solution.Kinetic data were well described by pseudo second-order model and adsorption isotherms were fitted with both Langmuir and Freundlich models with maximum adsorption capacity of 18.80 mg/g.SCMN adsorbents provided a favorable adsorption capacity under high salinity conditions,and cadmium could easily be desorbed using mild organic acid solutions at low concentration.

  2. Thiosemicabazone based fluorescent chemosensor for transition metal ions in aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Udhayakumari, Duraisamy; Suganya, Sivalingam; Velmathi, Sivan, E-mail: velmathis@nitt.edu

    2013-09-15

    Highly efficient fluorescent chemosensors for metal ions have been synthesized by using thiosemicarbazide and aromatic aldehydes. Detection of transition metal ions was performed via UV–vis and fluorescence spectroscopic methods. This is the first report on thiosemicarbazone based sensor capable of detecting transition metal ions in aqueous medium. The binding constant, stoichiometry of the complex were confirmed by using B–H plot and Job's plot method. The fluorescence enhancement of thiosemicarbazones on binding with Hg{sup 2+}, Zn{sup 2+}, Co{sup 2+}, Ni{sup 2+} and Sn{sup 2+} ions is due to the inhibition of photoinduced electron transfer mechanism whereas, quenching of fluorescence is attributed to the photoinduced electron transfer mechanism in case of Cu{sup 2+} and Mn{sup 2+} ions. -- Graphical abstract: Three highly sensitive aromatic thiosemicarbazones act as a fluorescent chemosensor for cations. Detection of transition metal ions was performed via UV–vis and fluorescence spectroscopic methods. This represents the first report on thiosemicarbazone based sensor capable of detecting transition metal ions in aqueous medium. The binding constant, stoichiometry of the complex was confirmed by using B–H plot and Job's plot method. The fluorescence enhancement of thiosemicarbazones on binding with Hg{sup 2+} , Zn{sup 2+}, Co{sup 2+}, Ni{sup 2+} and Sn{sup 2+} ions is due to the inhibition of photoinduced electron transfer whereas, in the case of Cu{sup 2+} and Mn{sup 2+} ions quenching of fluorescence occurring is attributed to the photoinduced electron transfer mechanism. Highlights: • The receptors were synthesized and studied for its optical/fluorescence emission properties. • R1+Zn{sup 2+}/Co{sup 2+}/Ni{sup 2+} and R2+Hg{sup 2+}/Sn{sup 2+} exhibits fluorescence enhancement via inhibition of PET. • R1+Cu{sup 2+} and R3+Mn{sup 2+} exhibits fluorescence quenching via PET mechanism.

  3. Measurement of Cadmium Ion in the Presence of Metal-Binding Biopolymers in Aqueous Sample

    Science.gov (United States)

    Pu, Jian; Fukushi, Kensuke

    2013-01-01

    In aqueous environment, water-soluble polymers are effectively used to separate free metal ions from metal-polymer complexes. The feasibilities of four different analytical techniques, cadmium ion-selective electrode, dialysis sack, chelate disk cartridge, and ultrafiltration, in distinguishing biopolymer-bound and nonbound cadmium in aqueous samples were investigated. And two different biopolymers were used, including bovine serum albumin (BSA) and biopolymer solution extracted from cultivated activated sludge (ASBP). The ISE method requires relatively large amount of sample and contaminates sample during the pretreatment. After the long reaction time of dialysis, the equilibrium of cadmium in the dialysis sack would be shifted. Due to the sample nature, chelate disk cartridge could not filter within recommended time, which makes it unavailable for biopolymer use. Ultrafiltration method would not experience the difficulties mentioned above. Ultrafiltration method measuring both weakly and strongly bound cadmium was included in nominally biopolymer-cadmium complex. It had significant correlation with the Ion-selective electrode (ISE) method (R2 = 0.989 for BSA, 0.985 for ASBP). PMID:24194678

  4. Measurement of Cadmium Ion in the Presence of Metal-Binding Biopolymers in Aqueous Sample

    Directory of Open Access Journals (Sweden)

    Jian Pu

    2013-01-01

    Full Text Available In aqueous environment, water-soluble polymers are effectively used to separate free metal ions from metal-polymer complexes. The feasibilities of four different analytical techniques, cadmium ion-selective electrode, dialysis sack, chelate disk cartridge, and ultrafiltration, in distinguishing biopolymer-bound and nonbound cadmium in aqueous samples were investigated. And two different biopolymers were used, including bovine serum albumin (BSA and biopolymer solution extracted from cultivated activated sludge (ASBP. The ISE method requires relatively large amount of sample and contaminates sample during the pretreatment. After the long reaction time of dialysis, the equilibrium of cadmium in the dialysis sack would be shifted. Due to the sample nature, chelate disk cartridge could not filter within recommended time, which makes it unavailable for biopolymer use. Ultrafiltration method would not experience the difficulties mentioned above. Ultrafiltration method measuring both weakly and strongly bound cadmium was included in nominally biopolymer-cadmium complex. It had significant correlation with the Ion-selective electrode (ISE method (R2=0.989 for BSA, 0.985 for ASBP.

  5. An Aqueous Metal-ion Capacitor with Oxidised Carbon Nanotubes and Metallic Zinc Electrodes

    Directory of Open Access Journals (Sweden)

    Yuheng Tian

    2016-10-01

    Full Text Available An aqueous metal ion capacitor comprising of a zinc anode, an oxidized carbon nanotubes (oCNTs cathode and a zinc sulfate electrolyte is reported. Since the shuttling cation is Zn2+, this typical metal ion capacitor is named as zinc-ion capacitor (ZIC. The ZIC integrates the divalent zinc stripping/plating chemistry with the surface-enabled pseudocapacitive cation adsorption/desorption on oCNTs. The surface chemistry and crystallographic structure of oCNTs were extensively characterized by combining X-ray photoelectron spectroscopy, Fourier-transformed infrared spectroscopy, Raman spectroscopy and X-ray powder diffraction. The function of the surface oxygen groups in surface cation storage was elucidated by a series of electrochemical measurement and the surface-enabled ZIC showed better performance than the ZIC with an un-oxidized CNT cathode. The reaction mechanism at the oCNT cathode involves the additional reversible Faradaic process, while the CNTs merely show electric double layer capacitive behavior involving a non-Faradaic process. The aqueous hybrid ZIC comprising the oCNT cathode exhibited a specific capacitance of 20 mF cm-2 (corresponding to 53 F g-1 in the range of 0-1.8 V at 10 mV s-1 and a stable cycling performance up to 5000 cycles.

  6. Adsorption of phosphate ions from an aqueous solution by calcined nickel-cobalt binary hydroxide.

    Science.gov (United States)

    Ogata, Fumihiko; Ueta, Erimi; Toda, Megumu; Otani, Masashi; Kawasaki, Naohito

    2017-01-01

    Different molar ratios of a Ni/Co binary hydroxide (NiCo82, NiCo91, and Ni100) were prepared and calcined at 270 °C (NiCo82-270, NiCo91-270, and Ni100-270). The properties of the adsorbents and the amount of adsorbed phosphate ions were evaluated. The adsorbents calcined at 270 °C had a nickel oxide structure. The amount of adsorbed phosphate ions, the amount of hydroxyl groups, and the specific surface area of the calcined adsorbents at 270 °C were greater than those of the uncalcined adsorbents. The amount of adsorbed phosphate ions was related to the amount of hydroxyl groups and the specific surface area; the correlation coefficients were 0.966 and 0.953, respectively. The adsorption isotherm data for NiCo91 and NiCo91-270 were fit to both the Freundlich and Langmuir equations. The amount of adsorbed phosphate ions increased with increasing temperature. The experimental data fit the pseudo-second-order model better than the pseudo-first-order model. A neutral pH was optimal for phosphate ion adsorption. In addition, the phosphate ions that were adsorbed onto NiCo91-270 could be recovered using sodium hydroxide, and the adsorbent was useful for the repetitive adsorption/desorption of phosphate ions. Collectively, these results suggest that NiCo91-270 is prospectively useful for the adsorption of phosphate ions from aqueous solutions.

  7. Extraction of copper(II) ions from aqueous solutions with a methimazole-based ionic liquid.

    Science.gov (United States)

    Reyna-González, Juan M; Torriero, Angel A J; Siriwardana, Amal I; Burgar, Iko M; Bond, Alan M

    2010-09-15

    The recently synthesized ionic liquid (IL) 2-butylthiolonium bis(trifluoromethanesulfonyl)amide, [mimSBu][NTf(2)], has been used for the extraction of copper(II) from aqueous solution. The pH of the aqueous phase decreases upon addition of [mimSBu](+), which is attributed to partial release of the hydrogen attached to the N(3) nitrogen atom of the imidazolium ring. The presence of sparingly soluble water in [mimSBu][NTf(2)] also is required in solvent extraction studies to promote the incorporation of Cu(II) into the [mimSBu][NTf(2)] ionic liquid phase. The labile copper(II) system formed by interacting with both the water and the IL cation component has been characterized by cyclic voltammetry as well as UV-vis, Raman, and (1)H, (13)C, and (15)N NMR spectroscopies. The extraction process does not require the addition of a complexing agent or pH control of the aqueous phase. [mimSBu][NTf(2)] can be recovered from the labile copper-water-IL interacting system by washing with a strong acid. High selectivity of copper(II) extraction is achieved relative to that of other divalent cobalt(II), iron(II), and nickel(II) transition-metal cations. The course of microextraction of Cu(2+) from aqueous media into the [mimSBu][NTf(2)] IL phase was monitored in situ by cyclic voltammetry using a well-defined process in which specific interaction with copper is believed to switch from the ionic liquid cation component, [mimSBu], to the [NTf(2)] anion during the course of electrochemical reduction from Cu(II) to Cu(I). The microextraction-voltammetry technique provides a fast and convenient method to determine whether an IL is able to extract electroactive metal ions from an aqueous solution.

  8. Adsorptive removal of nickel(II) ions from aqueous environment: A review.

    Science.gov (United States)

    Raval, Nirav P; Shah, Prapti U; Shah, Nisha K

    2016-09-01

    Among various methods adsorption can be efficiently employed for the treatment of heavy metal ions contaminated wastewater. In this context the authors reviewed variety of adsorbents used by various researchers for the removal of nickel(II) ions from aqueous environment. One of the objectives of this review article is to assemble the scattered available enlightenment on a wide range of potentially effective adsorbents for nickel(II) ions removal. This work critically assessed existing knowledge and research on the uptake of nickel by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites. The system's performance is evaluated with respect to the overall metal removal and the adsorption capacity. In addition, the equilibrium adsorption isotherms, kinetics and thermodynamics data as well as various optimal experimental conditions (solution pH, equilibrium contact time and dosage of adsorbent) of different adsorbents towards Ni(II) ions were also analyzed. It is evident from a literature survey of more than 190 published articles that agricultural solid waste materials, natural materials and biosorbents have demonstrated outstanding adsorption capabilities for Ni(II) ions.

  9. Interfacial behavior of perchlorate versus chloride ions in saturated aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosal, S; Kuo, I W; Baer, M D; Bluhm, H

    2009-04-14

    In recent years combination of theoretical and experimental work have presented a novel view of the aqueous interface wherein hard and/or multiply charged ions are excluded from the interface, but large polarizable anions show interfacial enhancement relative to the bulk. The observed trend in the propensity of anions to adsorb at the air/water interface appears to be reverse of the Hofmeister series for anions. This study focuses on experimental and theoretical examination of the partitioning behavior of perchlorate (ClO{sub 4}{sup -}) and chloride (Cl{sup -}) ions at the air/water interface. We have used ambient pressure X-ray photoelectron spectroscopy technique to directly probe the interfacial concentrations of ClO{sub 4}{sup -} and Cl{sup -} ions in sodium perchlorate and sodium chloride solutions, respectively. Experimental observations are compared with first principles molecular dynamics simulations. Both experimental and simulation results show enhancement of ClO{sub 4}{sup -} ion at the interface, compared with the absence of such enhancement in the case of Cl{sup -} ion. These observations are in agreement with the expected trend in the interfacial propensity of anions based on the Hofmeister series.

  10. Test of Lorentz symmetry with trapped ions

    Science.gov (United States)

    Pruttivarasin, Thaned

    2016-05-01

    The outcome of an experiment should not depend on the orientation of the apparatus in space. This important cornerstone of physics is deeply engrained into the Standard Model of Physics by requiring that all fields must be Lorentz invariant. However, it is well-known that the Standard Model is incomplete. Some theories conjecture that at the Planck scale Lorentz symmetry might be broken and measurable at experimentally accessible energy scales. Therefore, a search for violation of Lorentz symmetry directly probes physics beyond the Standard model. We present a novel experiment utilizing trapped calcium ions as a direct probe of Lorentz-violation in the electron-photon sector. We monitor the energy between atomic states with different orientations of the electronic wave-functions as they rotate together with the motion of the Earth. This is analogous to the famous Michelson-Morley experiment. To remove magnetic field noise, we perform the experiment with the ions prepared in the decoherence-free states. Our result improves on the most stringent bounds on Lorentz symmetry for electrons by 100 times. The experimental scheme is readily applicable to many ion species, hence opening up paths toward much improved test of Lorentz symmetry in the future. (Ph. D. Advisor: Hartmut Haeffner, University of California, Berkeley).

  11. An ion-optical bench for testing ion source lenses

    Science.gov (United States)

    Stoffels, J. J.; Ells, D. R.

    1988-06-01

    An ion-optical bench has been designed and constructed to obtain experimental data on the focusing properties of ion lenses in three dimensions. The heart of the apparatus is a position-sensitive detector (PSD) that gives output signals proportional to the x and y positions of each ion impact. The position signals can be displayed on an oscilloscope screen and analyzed by a two-parameter pulse-height analyzer, thereby giving a visual picture of the ion beam cross section and intensity distribution. The PSD itself is mounted on a track and is movable during operation from a position immediately following the ion lens to 30 cm away. This enables the rapid collection of accurate data on the intensity distribution and divergence angles of ions leaving the source lens. Examples of ion lens measurements are given.

  12. Characteristics and quantitative of negative ion in salt aqueous solution by Raman spectroscopy at -170℃

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The results from Raman spectroscopy analysis of salt aqueous solutions at -170℃ demonstrate that for those clearly sharp iron peaks whose Raman wavenumber is close to each other such as and , their original shape could be restorable by the stripping technique, and that ice's sharp characteristic peak (3090-3109 cm-1) is steady, while the spectrum band of the complex compound (nCl--[H+-OH-]n) chlorine ion combined chemically with water molecule is 3401-3413 cm-1. On the other hand, the research shows that the higher the negative iron concentration, the stronger its Raman characteristic peak intensity and the smaller the ice's. Based on the number of data and theoretical work, the strong correlation of the molar concentration of negative ion with the band area ratio is built up. Moreover, the developed Raman method is successfully used in the component analysis of the field fluid inclusions from Silurian sandstone in Tarim basin.

  13. Biologically derived melanin electrodes in aqueous sodium-ion energy storage devices.

    Science.gov (United States)

    Kim, Young Jo; Wu, Wei; Chun, Sang-Eun; Whitacre, Jay F; Bettinger, Christopher J

    2013-12-24

    Biodegradable electronics represents an attractive and emerging paradigm in medical devices by harnessing simultaneous advantages afforded by electronically active systems and obviating issues with chronic implants. Integrating practical energy sources that are compatible with the envisioned operation of transient devices is an unmet challenge for biodegradable electronics. Although high-performance energy storage systems offer a feasible solution, toxic materials and electrolytes present regulatory hurdles for use in temporary medical devices. Aqueous sodium-ion charge storage devices combined with biocompatible electrodes are ideal components to power next-generation biodegradable electronics. Here, we report the use of biologically derived organic electrodes composed of melanin pigments for use in energy storage devices. Melanins of natural (derived from Sepia officinalis) and synthetic origin are evaluated as anode materials in aqueous sodium-ion storage devices. Na(+)-loaded melanin anodes exhibit specific capacities of 30.4 ± 1.6 mAhg(-1). Full cells composed of natural melanin anodes and λ-MnO2 cathodes exhibit an initial potential of 1.03 ± 0.06 V with a maximum specific capacity of 16.1 ± 0.8 mAhg(-1). Natural melanin anodes exhibit higher specific capacities compared with synthetic melanins due to a combination of beneficial chemical, electrical, and physical properties exhibited by the former. Taken together, these results suggest that melanin pigments may serve as a naturally occurring biologically derived charge storage material to power certain types of medical devices.

  14. Calix[4]arene based dipodal receptor nanohybrids for selective determination of chloride ions in aqueous media.

    Science.gov (United States)

    Kaur, Harpreet; Singh, Jasminder; Chopra, Shweta; Kaur, Navneet

    2016-01-01

    A chemical sensor based on p-tert butyl calix[4]arene has been synthesized and characterized using an assortment of spectroscopic techniques such as (1)H NMR, (13)C NMR, and elemental analysis. For sensor application, organic nanoparticles (N1) of 1 have been primed by implementing re-precipitation technique, which were further employed for preparing organic-inorganic hybrid (H1) by decorating N1 with gold nanoparticles. Both N1 and H1 were characterized using UV-visible, fluorescence, and DLS studies. Photo-physical changes due to anion binding with H1 were scrutinized using UV-visible absorption spectrometer and found it to promptly and selectively recognize Cl(-) ions in aqueous media. Thus, H1 can be effectively used for recognition of Cl(-) ions in aqueous media over a wide pH range, in samples of real time importance with a detection limit of 2.84×10(-9) M with a linear detection range up to 50 μM.

  15. Removal of cadmium and zinc ions from aqueous solution by living Aspergillus niger

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-guo; FAN Ting; ZENG Guang-ming; LI Xin; TONG Qing; YE Fei; ZHOU Ming; XU Wei-hua; HUANG Yu-e

    2006-01-01

    The potential of living Aspergillus niger to remove cadmium and zinc from aqueous solution was investigated. Effects of pH, initial concentration, contact time, temperature and agitation rate on the biosorption of Cd(Ⅱ) and Zn(Ⅱ) ions were studied. The optimum adsorption pH value for Cd(Ⅱ) and Zn(Ⅱ) were 4.0 and 6.0. The best temperature and agitation rate were in the range of 25-30 ℃ and 120 r/min for all metal ions. Under the optimal conditions, the maximum uptake capacities of Cd(Ⅱ) and Zn( Ⅱ ) ions are 15.50 mg/g and 23.70 mg/g at initial concentrations of 75 mg/L and 150 mg/L, respectively. Biosorption equilibrium is established within 24 h for cadmium and zinc ions. The adsorption data provide an excellent fit to Langmuir isotherm model. The results of the kinetic studies show that the rate of adsorption follows the pseudo-second order kinetics.

  16. Aspiration tests in aqueous foam using a breathing simulator

    Energy Technology Data Exchange (ETDEWEB)

    Archuleta, M.M.

    1995-12-01

    Non-toxic aqueous foams are being developed by Sandia National Laboratories (SNL) for the National Institute of Justice (NIJ) for use in crowd control, cell extractions, and group disturbances in the criminal justice prison systems. The potential for aspiration of aqueous foam during its use and the resulting adverse effects associated with complete immersion in aqueous foam is of major concern to the NIJ when examining the effectiveness and safety of using this technology as a Less-Than-Lethal weapon. This preliminary study was designed to evaluate the maximum quantity of foam that might be aspirated by an individual following total immersion in an SNL-developed aqueous foam. A.T.W. Reed Breathing simulator equipped with a 622 Silverman cam was used to simulate the aspiration of an ammonium laureth sulfate aqueous foam developed by SNL and generated at expansion ratios in the range of 500:1 to 1000:1. Although the natural instinct of an individual immersed in foam is to cover their nose and mouth with a hand or cloth, thus breaking the bubbles and decreasing the potential for aspiration, this study was performed to examine a worst case scenario where mouth breathing only was examined, and no attempt was made to block foam entry into the breathing port. Two breathing rates were examined: one that simulated a sedentary individual with a mean breathing rate of 6.27 breaths/minute, and one that simulated an agitated or heavily breathing individual with a mean breathing rate of 23.7 breaths/minute. The results of this study indicate that, if breathing in aqueous foam without movement, an air pocket forms around the nose and mouth within one minute of immersion.

  17. Supramolecular coordination chemistry in aqueous solution: lanthanide ion-induced triple helix formation.

    Science.gov (United States)

    Lessmann, J J; Horrocks, W D

    2000-07-24

    The self-assembly of dinuclear triple helical lanthanide ion complexes (helicates), in aqueous solution, is investigated utilizing laser-induced, lanthanide luminescence spectroscopy. A series of dinuclear lanthanide (III) helicates (Ln(III)) based on 2,6-pyridinedicarboxylic acid (dipicolinic acid, dpa) coordinating units was synthesized by linking two dpa moieties using the organic diamines (1R,2R)-diaminocyclohexane (chxn-R,R) and 4,4'-diaminodiphenylmethane (dpm). Luminescence excitation spectroscopy of the Eu3+ 7F0-->5D0 transition shows the apparent cooperative formation of neutral triple helical complexes in aqueous solution, with a [Eu2L3] stoichiometry. Eu3+ excitation peak wavelengths and excited-state lifetimes correspond to those of the [Eu(dpa)3]3- model complex. CD studies of the Nd(III) helicate Nd2(dpa-chxn-R,R)3 reveal optical activity of the f-f transitions, indicating that the chiral linking group induces a stable chirality at the metal ion center. Molecular mechanics calculations using CHARMm suggest that the delta delta configuration at the Nd3+ ion centers is induced by the chxn-R,R linker. Stability constants were determined for both ligands with Eu3+, yielding identical results: log K = 31.6 +/- 0.2 (K in units of M-4). Metal-metal distances calculated from Eu3+-->Nd3+ energy-transfer experiments show that the complexes have metal-metal distances close to those calculated by molecular modeling. The fine structure in the Tb3+ emission bands is consistent with the approximate D3 symmetry as anticipated for helicates.

  18. Photochemical oxidation of chloride ion by ozone in acid aqueous solution.

    Science.gov (United States)

    Levanov, Alexander V; Isaykina, Oksana Ya; Amirova, Nazrin K; Antipenko, Ewald E; Lunin, Valerii V

    2015-11-01

    The experimental investigation of chloride ion oxidation under the action of ozone and ultraviolet radiation with wavelength 254 nm in the bulk of acid aqueous solution at pH 0-2 has been performed. Processes of chloride oxidation in these conditions are the same as the chemical reactions in the system O3 - OH - Cl(-)(aq). Despite its importance in the environment and for ozone-based water treatment, this reaction system has not been previously investigated in the bulk solution. The end products are chlorate ion ClO3(-) and molecular chlorine Cl2. The ions of trivalent iron have been shown to be catalysts of Cl(-) oxidation. The dependencies of the products formation rates on the concentrations of O3 and H(+) have been studied. The chemical mechanism of Cl(-) oxidation and Cl2 emission and ClO3(-) formation has been proposed. According to the mechanism, the dominant primary process of chloride oxidation represents the complex interaction with hydroxyl radical OH with the formation of Cl2(-) anion-radical intermediate. OH radical is generated on ozone photolysis in aqueous solution. The key subsequent processes are the reactions Cl2(-) + O3 → ClO + O2 + Cl(-) and ClO + H2O2 → HOCl + HO2. Until the present time, they have not been taken into consideration on mechanistic description and modelling of Cl(-) oxidation. The final products are formed via the reactions 2ClO → Cl2O2, Cl2O2 + H2O → 2H(+) + Cl(-) + ClO3(-) and HOCl + H(+) + Cl(-) ⇄ H2O + Cl2. Some portion of chloride is oxidized directly by O3 molecule with the formation of molecular chlorine in the end.

  19. INVESTIGATION OF CLINOPTILOLITE NATURAL ZEOLITE REGENERATION BY AIR STRIPPING FOLLOWED BY ION EXCHANGE FOR REMOVAL OF AMMONIUM FROM AQUEOUS SOLUTIONS

    Directory of Open Access Journals (Sweden)

    A. R. Rahmani ، M. T. Samadi ، H. R. Ehsani

    2009-07-01

    Full Text Available The purpose of this study was to regenerate clinoptilolite natural zeolite by air stripping followed by removal of ammonium from aqueous solutions. The research was carried out in continuous system. The characteristics of graded clinoptilolite from Semnan (one of the central provinces in Iran mines were determined and then regeneration tests were done by contacting of 1 N NaCl solution with given weights of ammonium saturated zeolite. Then the brine of column was transferred to the air stripping column for regeneration. The pH of brine solution before entrance to a stripping column was increased to 11. Air stripped ammonia from the brine was converted to the ammonium ion by using acid scrubber. The outlet effluent from stripping column was collected for reuse. The results showed that the cation exchange capacities were 17.31 to 18.38 mg NH4+/g of zeolite weight. Regeneration efficiency of zeolite by NaCl solution and air stripping was in the range of 92%-97% under various operational conditions. However, the efficiency of acid absorption of released ammonia in stripping process was 55% with a major rejection of the surplus ammonia to the atmosphere. It could be concluded that the method studied may be considered as an advanced and supplementary process for treating effluents of aqueous solution and fishponds in existing treatment plants.

  20. New Data on Activity Coefficients of Potassium, Nitrate, and Chloride Ions in Aqueous Solutions of KNO3 and KCl by Ion Selective Electrodes

    OpenAIRE

    Debasmita Dash; Shekhar Kumar; C. Mallika; U. Kamachi Mudali

    2012-01-01

    Ion selective electrodes (ISEs) are used to measure the single-ion activity coefficients in aqueous solutions of KNO3 and KCl at 298.15 K against a double-junction reference electrode. The EMF responses of ISEs up to 0.01 m are plotted to obtain the slope and intercept values. The obtained slopes and intercepts are used in Nernst equation for higher concentrated solutions for calculation of individual ion activity coefficient. The mean ionic activity coefficients are estimated from single ion...

  1. Removal of Pb(II) ions from aqueous solutions by sulphuric acid-treated wheat bran.

    Science.gov (United States)

    Ozer, A

    2007-03-22

    Sulphuric acid-treated wheat bran (STWB) was used as an adsorbent to remove Pb(II) ions from aqueous solution. It was observed that the adsorption yield of Pb(II) ions was found to be pH dependent. The equilibrium time for the process was determined as 2h. STWB gave the highest adsorption yield at around pH 6.0. At this pH, adsorption percentage for an initial Pb(II) ions concentration of 100mg/L was found to be 82.8 at 25 degrees C for contact time of 2h. The equilibrium data obtained at different temperatures fitted to the non-linear form of Langmuir, Freundlich and Redlich-Peterson and linear form of Langmuir and Freundlich models. Isotherm constants were calculated and compared for the models used. The maximum adsorption capacity (q(max)) which was obtained linear form of Langmuir model increased from 55.56 to 79.37mg/g with increasing temperature from 25 to 60 degrees C. Similar trend was observed for other isotherm constants related to the adsorption capacity. Linear form of Langmuir isotherm data was evaluated to determine the thermodynamic parameters for the process. Thermodynamic parameters show that adsorption process of Pb(II) ions is an endothermic and more effective process at high temperatures. The pseudo nth order kinetic model was successfully applied to the kinetic data and the order (n) of adsorption reaction was calculated at the range from 1.711 to 1.929. The values of k(ad) were found to be 5.82x10(-4) and 21.81x10(-4)(min(-1))(mg/g)(1-n) at 25 and 60 degrees C, respectively. Activation energy was determined as 29.65kJ/mol for the process. This suggest that the adsorption Pb(II) ions by STWB is chemically controlled.

  2. BIOSORPTION STUDIES OF CADMIUM (II IONS FROM AQUEOUS SOLUTIONS ONTO ORANGE RIND (CITRUS SINENSIS L. OSBECK

    Directory of Open Access Journals (Sweden)

    Satish A. Bhalerao

    2015-03-01

    Full Text Available The biosorption studies for effective removal of cadmium (II ions from aqueous solutions using orange rind (Citrus sinensis L. Osbeck, cost effective biosorbent, was carried out in batch system. FTIR analysis of biosorbent confirmed that carboxyl, hydroxyl, carbonyl group which was responsible for biosorption of cadmium (II ions. The SEM represents porous structure with surface area. The effects of operational factors including solution pH, biosorbent dose, initial cadmium (II ions concentration, contact time and temperature were studied. The optimum solution pH for cadmium (II ions biosorption by biosorbent was 7.0 with the optimal removal 80.30 %. The biosorbent dose 5 mg/ml was enough for optimal removal of 65.15 %. The biosorption process was relatively fast and equilibrium was achieved after 90 minutes of contact. The experimental equilibrium biosorption data were analysed by four widely used two-parameters Langmuir, Freundlich, Dubinin-Kaganer-Redushkevich (DKR and Temkin isotherm models. Langmuir isotherm model provided a better fit with the experimental data than Freundlich, Temkin and Dubinin-Kaganer-Redushkevich (DKR isotherm models by high correlation coefficient value (R2 = 0.911. The maximum adsorption capacity determined from Langmuir isotherm was found to be 83.33 mg/g of biosorbent. Simple kinetic models such as pseudo-first-order, pseudo-second-order, Elovich equation and Weber and Morris intra-particle diffusion rate equation were employed to determine the adsorption mechanism. Results clearly indicates that the pseudo-second-order kinetic model (R2 = 0.998 was found to be correlate the experimental data strongest than other three kinetic models and this suggests that chemical adsorption process was more dominant. Thermodynamic study revealed that the biosorption process was spontaneous, endothermic and increasing randomness of the solid solution interfaces. Orange rind (Citrus sinensis L. Osbeck was successfully used for the

  3. Evaluation of biosurfactants grown in corn oil by Rhodococcus rhodochrous on removing of heavy metal ion from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Suryanti, Venty, E-mail: venty@mipa.uns.ac.id; Hastuti, Sri; Pujiastuti, Dwi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Sebelas Maret University Jl. Ir. Sutami 36A, Surakarta, Central Java 57126 (Indonesia)

    2016-02-08

    The potential application of biosurfactants to remove heavy metal ion from aqueous solution by batch technique was examined. The glycolipids type biosurfactants were grown in a media containing of 20% v/v corn oil with 7 days of fermentation by Rhodococcus rhodochrous. The biosurfactants reduced the surface tension of water of about 51% from 62 mN/m to 30 mN/m. The biosurfactant increased the E24 of water-palm oil emulsion of about 55% from 43% to 97% and could maintain this E24 value of above 50% for up to 9 days. Heavy metal ion removal, in this case cadmium ion, by crude and patially purified biosurfactants has been investigated from aqueous solution at pH 6. Adsorption capacity of Cd(II) ion by crude biosurfactant with 5 and 10 minutes of contact times were 1.74 and 1.82 mg/g, respectively. Additionally, the adsorption capacity of Cd(II) ion by partially purified biosurfactant with 5 and 10 minutes of contact times were 0.79 and 1.34 mg/g, respectively. The results demonstrated that the adsorption capacity of Cd(II) ion by crude biosurfactant was higher than that of by partially purified biosurfactant. The results suggested that the biosurfactant could be used in the removal of heavy metal ions from aqueous solution.

  4. Evaluation of biosurfactants grown in corn oil by Rhodococcus rhodochrous on removing of heavy metal ion from aqueous solution

    Science.gov (United States)

    Suryanti, Venty; Hastuti, Sri; Pujiastuti, Dwi

    2016-02-01

    The potential application of biosurfactants to remove heavy metal ion from aqueous solution by batch technique was examined. The glycolipids type biosurfactants were grown in a media containing of 20% v/v corn oil with 7 days of fermentation by Rhodococcus rhodochrous. The biosurfactants reduced the surface tension of water of about 51% from 62 mN/m to 30 mN/m. The biosurfactant increased the E24 of water-palm oil emulsion of about 55% from 43% to 97% and could maintain this E24 value of above 50% for up to 9 days. Heavy metal ion removal, in this case cadmium ion, by crude and patially purified biosurfactants has been investigated from aqueous solution at pH 6. Adsorption capacity of Cd(II) ion by crude biosurfactant with 5 and 10 minutes of contact times were 1.74 and 1.82 mg/g, respectively. Additionally, the adsorption capacity of Cd(II) ion by partially purified biosurfactant with 5 and 10 minutes of contact times were 0.79 and 1.34 mg/g, respectively. The results demonstrated that the adsorption capacity of Cd(II) ion by crude biosurfactant was higher than that of by partially purified biosurfactant. The results suggested that the biosurfactant could be used in the removal of heavy metal ions from aqueous solution.

  5. EPR study of complex formation between copper (II) ions and sympathomimetic amines in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Preoteasa, E.A. [Inst. of Atomic Physics, IFIN, Bucharest (Romania); Duliu, O.G.; Grecu, V.V. [Bucharest, Univ. (Romania). Dept. of Atomic and Nuclear Physics

    1997-07-01

    The complex formation between sympathomimetic amines (SA): adrenaline (AD), noradrenaline (NA), dopamine (DA), ephedrine (ED) and p-tyramine (pTA), and Cu(II) ion in aqueous solution has been studied by X-band EPR at room temperature. Excepting pTA, all investigated SA yielded two types of complexes in different pH domains. All complexes consistent with a ligand fields having a distorted octahedral symmetry, i.e., hexacoordination of Cu(II). The covalence coefficient calculated from the isotropic g and A values has shown strong ionic sigma-type ligand bonds. A structural model with the Cu(II) ion bound by four catecholic O(hydroxy) atoms for the low pH complexes of AD, NA and DA is proposed. For the high pH complexes of the former compounds as well as for both Ed complexes, the authors suppose Cu(II) bound by two N (amino) and two O (hydroxy) atoms. The spectra are consistent to water binding on the longitudinal octahedron axis in all compounds excepting the high pH complex of Ed, where OH2- ions are bound. Possible implications for the SA-cell receptors interactions are discussed.

  6. Removal of ammonium ion from aqueous solution using natural Turkish clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Karadag, Dogan [Yildiz Technical University, Civil Engineering Faculty, Environmental Engineering Department, 34349 Besiktas, Istanbul (Turkey)]. E-mail: dkaradag@yildiz.edu.tr; Koc, Yunus [Yildiz Technical University, Civil Engineering Faculty, Environmental Engineering Department, 34349 Besiktas, Istanbul (Turkey); Turan, Mustafa [Istanbul Technical University, Civil Engineering Faculty, Environmental Engineering Department, 34469 Maslak, Istanbul (Turkey); Armagan, Bulent [Harran University, Engineering Faculty, Environmental Engineering Department, 63300 Sanliurfa (Turkey)

    2006-08-25

    A study on ion exchange kinetics and equilibrium isotherms of ammonium ion on natural Turkish clinoptilolite (zeolite) was conducted using a batch experiment technique. The effects of relevant parameters, such as temperature, contact time and initial ammonium (NH{sub 4} {sup +}) concentration were examined, respectively. The pseudo first-order, pseudo second-order kinetic models and intraparticle diffusion model were used to describe the kinetic data. The pseudo second-order kinetic model provided excellent kinetic data fitting (R {sup 2} > 0.990) and intraparticle diffusion effects ammonium uptake. The Langmuir and Freundlich models were applied to describe the equilibrium isotherms for ammonium uptake and the Langmuir model agrees very well with experimental data. Thermodynamic parameters such as change in free energy ({delta}G {sup 0}), enthalpy ({delta}H {sup 0}) and entropy ({delta}S {sup 0}) were also determined. An examination of the thermodynamic parameters shows that the exchange of ammonium ion by clinoptilolite is a process occurring spontaneously and physical in nature at ambient conditions (25 deg. C). The process is also found to be exothermic. The results indicate that there is a significant potential for the natural Turkish clinoptilolite as an adsorbent material for ammonium removal from aqueous solutions.

  7. 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.

  8. Evaluation of Two Biosorbents in the Removal of Metal Ions in Aqueous Using a Pilot Scale Fixed-bed System

    Directory of Open Access Journals (Sweden)

    Andre Gadelha Oliveira

    2014-05-01

    Full Text Available The aim of the present work was to investigate the adsorption of toxic metal ions copper, nickel and zinc from aqueous solutions using low cost natural biomass (sugar cane bagasse and green coconut fiber in pilot scale fixed-bed system. The Hydraulic retention time (HRT was 229 minutes and the lowest adsorbent usage rate (AUR found was 0.10 g.L-1 for copper using green coconut fibers. The highest values of adsorption capacities founded were 1.417 and 2.772 mg.g-1 of Cu(II ions for sugarcane bagasse and green coconut fibers, respectively. The results showed that both sugarcane bagasse and green coconut fiber presented potential in the removal of metal ions copper, nickel and zinc ions from aqueous solution and the possible use in wastewater treatment station.

  9. Boron removal from aqueous solutions by ion-exchange resin: column sorption-elution studies.

    Science.gov (United States)

    Köse, T Ennil; Oztürk, Neşe

    2008-04-01

    A column sorption-elution study was carried out by using a strong base anion-exchange resin (Dowex 2 x 8) for the removal of boron from aqueous solutions. The breakthrough curve was obtained as a function of feed flow rate and the total and breakthrough capacity values of the resin were calculated. The boron on the resin was quantitatively eluted with 0.5M HCl solution at different flow rates. Three consecutive sorption-elution-washing-regeneration-washing cycles were applied to the resin in order to investigate the reusability of the ion-exchange resin. Total capacity values remained almost the same after three sorption-elution-regeneration cycles. The Thomas and the Yoon-Nelson models were applied to experimental data to predict the breakthrough curves and to determine the characteristic column parameters required for process design. The results proved that the models would describe the breakthrough curves well.

  10. First Observation of Electron Transfer Mediated Decay in Aqueous Solutions: A Novel Probe of Ion Pairing

    CERN Document Server

    Unger, I; Thürmer, S; Aziz, E F; Cederbaum, L S; Muchová, E; Slavíček, P; Winter, B; Kryzhevoi, N V

    2016-01-01

    A major goal of many spectroscopic techniques is to provide comprehensive information on the local chemical environment. Electron transfer mediated decay (ETMD) is a sensitive probe of the environment since it is actively involved in this non-local radiationless decay process through electron and energy transfer steps. We report the first experimental observation of ETMD in the liquid phase. Using liquid-jet X-ray photoelectron spectroscopy we explore LiCl aqueous solution, and detect low-energy electrons unambiguously emerging from the ETMD processes of core-ionized Li+. We interpret the experimental results with molecular dynamics and high-level ab initio calculations. By considering various solvation-structure models we show that both water molecules and Cl- anions can participate in ETMD, with each process having its characteristic spectral fingerprint. Different ion associations lead to different spectral shapes. The potential application of the unique sensitivity of the ETMD spectroscopy to the local hy...

  11. Removal of copper ions from aqueous solution by calcium alginate immobilized kaolin

    Institute of Scientific and Technical Information of China (English)

    Yanhui Li; Yanzhi Xia; Bing Xia; Quansheng Zhao; Fuqiang Liu; Pan Zhang; Qiuju Du; Dechang Wang; Da Li; Zonghua Wang

    2011-01-01

    Kaolin has been widely used as an adsorbent to remove heavy metal ions from aqueous solutions. However, the lower heavy metal adsorption capacity of kaolin limits its practical application. A novel environmental friendly material, calcium alginate immobilized kaolin (kaolin/CA), was prepared using a sol-gel method. The effects of contact time, pH, adsorbent dose, and temperature on Cu2+ adsorption by kaolin/CA were investigated. The Langmuir isotherm was used to describe the experimental adsorption, the maximum Cu2+ adsorption capacity of the kaolin/CA reached up to 53.63 mg/g. The thermodynamic studies showed that the adsorption reaction was a spontaneous and endothermic process.

  12. Application of magnetic particles modified with amino groups to adsorb copper ions in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    Yafen Lin; Huawei Chen; Kaelong Lin; Boryann Chen; Chyowsan Chiou

    2011-01-01

    A magnetic adsorbent can be easily recovered from treated water by magnetic force, without requiring further downstream treatment.In this research, amine-functionalized silica magnetite has been synthesized using N-[3-(trimethoxysilyl)propyl]-ethylenediamine (TPED) as a surface modification agent.The synthesized magnetic amine adsorbents were used to adsorb copper ions in an aqueous solution in a batch system, and the maximum adsorption was found to occur at pH 5.5 ± 0.1.The adsorption equilibrium data fitted the Langmuir isotherm equation reasonably well, with a maximum adsorption capacity of 10.41 mg/g.A pseudo second-order model could best describe the adsorption kinetics, and the derived activation energy was 26.92 kJ/mol.The optimum condition to desorb Cu2+ from NH2/SiO2/Fe3O4 was provided by a solution with 0.1 mol/L HNO3.

  13. Poly(2-FurylMethylenesulfide as a Resin to Uptake of Metal Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Damasceno J.

    2002-01-01

    Full Text Available The polymerization of poly (2- furyl methylenesulfide -- POLYTHIOFURFURAL -- was performed in an 0.36 mol/L aqueous solution of furfuraldehyde, saturated by bubbling hydrogen sulfide for 2 h at different temperatures. The reaction product was thoroughly washed and dried at 40 °C under vacuum. Poly (2-furyl methylenesulfyde is a yellow powder with a rather unpleasant odor. The polythiofurfural obtained [ -CH(C4H3O-S-] is a furan with thiols end groups. These are active adsorption centers for metal ions. The polythiofurfural was soluble in acetone and chloroform and its yields attained 80%. Morphological analysis by Scanning Eletronic Microscopy indicates a regular and dense surface in an interesting spacial arrangement. Preliminary isotherms adsorption studies indicate specific affinity forNi (II and Co (II and different capacity adsorption, 0.022 and 0.045 mmol per gram, respectively.

  14. Nanoalginate based biosorbent for the removal of lead ions from aqueous solutions: Equilibrium and kinetic studies.

    Science.gov (United States)

    Geetha, P; Latha, M S; Pillai, Saumya S; Koshy, Mathew

    2015-12-01

    Population explosion, depletion of water resources and prolonged droughts and floods due to climatic change lead to scarcity of pure and hygienic drinking water in most of the developing countries. Recently nanomaterials attained considerable attention as biosorbent for water purification purpose. However difficulties in removing polymeric surfactants and organic solvents used for nanoproduction and instability of the generated nanoparticles limit the scope of this approach in water cleanup. Here, we describe a novel green method for synthesizing polysaccharide nanoparticles in aqueous medium using honey as the capping agent. The highly stable alginate nanoparticles, characterized by various microscopic and spectroscopic techniques, exhibited a maximum uptake capacity of 333 mg g (-1)of Pb(II) ions from aqueous solution. The effect of various parameters such as initial metal concentration, pH, contact time, temperature and adsorbent dose on sorption process was investigated in batch mode technique. The maximum removal percentage was 94.81 at 45 °C and at pH 4.5 in 60 min contact time. The biosorption followed Freundlich model indicating multilayer adsorption and pseudo second order kinetics. The mechanism involves both surface adsorption and pore diffusion. The positive values of ΔH°, ∆S° and the negative value of ΔG°, confirmed the endothermic nature, randomness and spontaneity of biosorption process.

  15. Alkaline deoxygenated graphene oxide as adsorbent for cadmium ions removal from aqueous solutions.

    Science.gov (United States)

    Liu, Jun; Du, Hongyan; Yuan, Shaowei; He, Wanxia; Yan, Pengju; Liu, Zhanhong

    2015-01-01

    Alkaline deoxygenated graphene oxide (aGO) was prepared through alkaline hydrothermal treatment and used as adsorbent to remove Cd(II) ions from aqueous solutions for the first time. The characterization results of transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and Fourier transform infrared (FT-IR) spectra indicate that aGO was successfully synthesized. The batch adsorption experiments showed that the adsorption kinetics could be described by the pseudo-second-order kinetic model, and the isotherms equilibrium data were well fitted with the Langmuir model. The maximum adsorption capacity of Cd(II) on aGO was 156 mg/g at pH 5 and T=293 K. The adsorption thermodynamic parameters indicated that the adsorption process was a spontaneous and endothermic reaction. The mainly adsorption mechanism speculated from FT-IR results may be attributed to the electrostatic attraction between Cd2+ and negatively charged groups (-CO-) of aGO and cation-π interaction between Cd2+ and the graphene planes. The findings of this study demonstrate the potential utility of the nanomaterial aGO as an effective adsorbent for Cd(II) removal from aqueous solutions.

  16. Speciation of phytate ion in aqueous solution. Alkali metal complex formation in different ionic media.

    Science.gov (United States)

    De Stefano, Concetta; Milea, Demetrio; Pettignano, Alberto; Sammartano, Silvio

    2003-08-01

    The acid-base properties of phytic acid [ myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate)] (H(12)Phy; Phy(12-)=phytate anion) were studied in aqueous solution by potentiometric measurements ([H+]-glass electrode) in lithium and potassium chloride aqueous media at different ionic strengths (0iodide (Et(4)NI; e.g., at I=0.5 mol L(-1), log K(3)(H)=11.7, 8.0, 9.1, and 9.1 in Et(4)NI, LiCl, NaCl and KCl, respectively; the protonation constants in Et(4)NI and NaCl were already reported), owing to the strong interactions occurring between the phytate and alkaline cations present in the background salt. We explained this in terms of complex formation between phytate and alkali metal ions. Experimental evidence allows us to consider the formation of 13 mixed proton-metal-ligand complexes, M(j)H(i)Phy((12-i-j)-), (M+ =Li+, Na+, K+), with jstability of alkali metal complexes follows the trend Li+ > or =Na+K+. Some measurements were also performed at constant ionic strength (I=0.5 mol L(-1)), using different mixtures of Et(4)NI and alkali metal chlorides, in order to confirm the formation of hypothesized and calculated metal-proton-ligand complex species and to obtain conditional protonation constants in these multi-component ionic media.

  17. Biosorption of copper (II) ions from synthetic aqueous solutions by drying bed activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Benaissa, H., E-mail: ho_benaissa@yahoo.fr [Laboratory of Sorbent Materials and Water Treatment, Department of Chemistry, Faculty of Sciences, University of Tlemcen, P.O. Box 119, 13000 Tlemcen (Algeria); Elouchdi, M.A. [Laboratory of Sorbent Materials and Water Treatment, Department of Chemistry, Faculty of Sciences, University of Tlemcen, P.O. Box 119, 13000 Tlemcen (Algeria)

    2011-10-30

    Highlights: {yields} Dried activated sludge has been investigated for the removal of copper ions from aqueous synthetic solutions, in batch conditions. {yields} Copper uptake was time contact, initial copper concentration, initial pH solution and copper salt type dependent. {yields} Maximum copper uptake obtained was q{sub m} = 62.50 mg/g (0.556 mmol/g) under the investigated experimental conditions. - Abstract: In the present work, the usefulness of dried activated sludge has been investigated for the removal of copper ions from synthetic aqueous solutions. Kinetic data and equilibrium sorption isotherm were measured in batch conditions. The influence of some parameters such as: contact time, initial copper concentration, initial pH of solution and copper salt nature on copper biosorption kinetics has been studied. Copper uptake was time contact, initial copper concentration, initial pH solution and copper salt type dependent. Maximum copper sorption was found to occur at initial pH 5. Two simplified kinetic models including a first-order rate equation and a pseudo second-order rate equation were selected to describe the biosorption kinetics. The process followed a pseudo second-order rate kinetics. The process mechanism was found to be complex, consisting of external mass transfer and intraparticle mass transfer diffusion. Copper biosorption process was particle-diffusion-controlled, with some predominance of some external mass transfer at the initial stages for the different experimental parameters studied. Langmuir and Freundlich models were used to describe sorption equilibrium data at natural pH of solution. Results indicated that the Langmuir model gave a better fit to the experimental data than the Freundlich model. Maximum copper uptake obtained was q{sub m} = 62.50 mg/g (0.556 mmol/g) under the investigated experimental conditions. Scanning electron microscopy coupled with X-ray energy dispersed analysis for copper-equilibrated dried activated sludge

  18. The effect of temperature on radiolysis of iodide ion diluted aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Gorbovitskaya, T.; Tiliks, J. [Latvia Univ., Lab. of Radiation Chemistry, Riga (Latvia)

    1996-12-01

    To investigate the radiolysis of iodine containing aqueous solutions a flow type facility (ITF) has a possibility to irradiate aqueous solutions in the steel vessel with {sup 60}Co {gamma}-rays and continuously (on line) to analyze the products of radiolysis both in liquid and in gaseous phases. By means of ITF the formation of I{sub ox} (I{sub 2} + I{sub 3}{sup -} + HOI), IO{sub 3}{sup -}, H{sub 2}O{sub 2} was studied in 10{sup -5} - 10{sup -3} mol/dm{sup 3} CsI aqueous solutions by their radiolysis at dose rate 4.5 kGv/h for six hours in region of temperatures from 313 to 404 K. Some experiments in glass ampoules were also performed. The steady-state concentrations of I{sub ox} and IO{sub 3}{sup -} decreased with increasing temperature as linear function of inverted temperature. The effect decreased with decreasing concentration of iodide ion. As the result, at high temperatures (T{>=}380 K) the steady-state concentration of I{sub ox} does not depend essentially on the iodide ion initial concentration. Molecular iodine (I{sub 2}) released from the solution was the main radiolysis product in gaseous phase. Its steady-state concentration increased with increasing temperature because of iodine solubility in the water and decreased at the same time because the radiolytic iodine concentrations decreased. Therefore the most volatility of irradiated 10{sup -3} and 10{sup -4}M CsI solutions was observed at the temperature about 350 K. The volatility of 10{sup -5}M solutions gradually decreased with increasing temperature. The experimental data were explained on the base of the hypothesis that the reaction between I{sub 2} and radiolytic H{sub 2}O{sub 2} was the limit one determining the temperature dependence of I{sub ox} and IO{sub 3}{sup -}steady-state concentrations. Its activation energy was estimated to be 27,5 kcal.mol{sup -1}. The temperature dependence for reaction (IO{sup -} + H{sub 2}O{sub 2}) was also estimated. (author) 8 figs., 1 tab., 17 refs.

  19. Selective flotation of zinc(II) and silver(I) ions from dilute aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Charewicz, W.A.; Holowiecka, B.A.; Walkowiak, W. [Wroclaw Univ. of Tech. (Poland)

    1999-09-01

    An experimental investigation is presented of the batch competitive flotation of zinc(II) and silver(I) ions from dilute aqueous solutions with sodium dodecylsulfate and ammonium tetradecysulfonate as anionic surfactants and with cetylpyridinium chloride as a cationic surfactant. The sequence of growing affinity of metal cations to anionic surfactants is the same as the sequence of ionic potential values of the studied cations: AG{sup +} < Zn{sup 2+}. The presence of potassium sulfate in aqueous solution has a negative influence of Zn{sup 2+} foam separation with a anionic surfactant which is due to competition for the surfactant between Zn{sup 2+} and K{sup +} cations. Also, the effect of inorganic ligands (i.e., thiosulfates, thiocyanates, and cyanides) on the selectivity of ion flotation of Zn(II) and Ag(I) is established. Results are discussed in terms of the complex species of zinc(II) and silver(I). At a total S{sub 2}O{sub 3}{sup 2{minus}} concentration of 3 {times} 10{sup {minus}6} M, the silver(I) is floated as a mixture of anions [Ag(S{sub 2}O{sub 3})]{sup {minus}} and [Ag(S{sub 2}O{sub 3}){sub 2}]{sup 3{minus}}, whereas zinc(II) remains in the aqueous phase as Zn{sup 2+}. At total concentrations of SCN{sup {minus}} from 1 {times} 10{sup {minus}4} to 2 {times} 10{sup {minus}3} M, silver(I) is floated as a mixture of [Ag(SCN){sub 2}]{sup {minus}} and AgSCN species. Partial separation of zinc(II) from silver(I) can be achieved in the presence of CN{sup {minus}} ligands at total concentrations varying from 2.5 {times} 10{sup {minus}4} to 1.0 {times} 10{sup {minus}3} M. The affinity of the studied cyanide complexes to cetylpyridinium chloride follows the order [Ag(CN){sub 2}]{sup {minus}} < [Zn(CN){sub 4}]{sup 2{minus}} + [Zn(CN){sub 3}]{sup {minus}}.

  20. Removal of Copper (II Ions from Aqueous Solutions by Adsorption with Low Cost Acid Activated Cynodon Dactylon Carbon

    Directory of Open Access Journals (Sweden)

    U. Gayathri

    2011-01-01

    Full Text Available The main purpose of this work was to exploit low cost and efficient sorbents for the removal of copper from aqueous solution using Cynodon dactylon carbon. It was observed from the experimental results that almost 90-100% copper can be removed from the aqueous solution. Adsorption kinetics and equilibrium have been investigated as a function of initial copper ion concentration. pH, contact time and adsorbent dosage. Kinetics studies suggested that the adsorption allowed first order reaction. Equilibrium data were analyzed using Langmuir and Freundlich isotherm models. On the basis of experimental results and the model parameters, it can be concluded that the carbonaceous Cynodon dactylon is effective for the removal of copper ion from aqueous solution.

  1. An Aqueous Symmetric Sodium-Ion Battery with NASICON-Structured Na3 MnTi(PO4 )3.

    Science.gov (United States)

    Gao, Hongcai; Goodenough, John B

    2016-10-04

    A symmetric sodium-ion battery with an aqueous electrolyte is demonstrated; it utilizes the NASICON-structured Na3 MnTi(PO4 )3 as both the anode and the cathode. The NASICON-structured Na3 MnTi(PO4 )3 possesses two electrochemically active transition metals with the redox couples of Ti(4+) /Ti(3+) and Mn(3+) /Mn(2+) working on the anode and cathode sides, respectively. The symmetric cell based on this bipolar electrode material exhibits a well-defined voltage plateau centered at about 1.4 V in an aqueous electrolyte with a stable cycle performance and superior rate capability. The advent of aqueous symmetric sodium-ion battery with high safety and low cost may provide a solution for large-scale stationary energy storage.

  2. Effects of Metal Ions on Viscosity of Aqueous Sodium Carboxylmethylcellulose Solution and Development of Dropping Ball Method on Viscosity

    Science.gov (United States)

    Set, Seng; Ford, David; Kita, Masakazu

    2015-01-01

    This research revealed that metal ions with different charges could significantly affect the viscosity of aqueous sodium carboxylmethylcellulose (CMC) solution. On the basis of an Ostwald viscometer, an improvised apparatus using a dropping ball for examining the viscosity of liquids/solutions has been developed. The results indicate that the…

  3. Thermochemical study of the processes of complexation of cobalt(II) ions with L-histidine in aqueous solution

    Science.gov (United States)

    Gorboletova, G. G.; Metlin, A. A.

    2015-09-01

    Thermal effects of the complexation of cobalt(II) ions with L-histidine at 298.15 K and several values of the ionic strength against the background of KNO3 are determined by means of direct calorimetry. The standard thermodynamic characteristics of the reactions of complexation in the aqueous solution have been calculated.

  4. On the influence of hydronium and hydroxide ion diffusion on the hydrogen and oxygen evolution reactions in aqueous media

    DEFF Research Database (Denmark)

    Wiberg, Gustav Karl Henrik; Arenz, Matthias

    2015-01-01

    We present a study concerning the influence of the diffusion of H+ and OH- ions on the hydrogen and oxygen evolution reactions (HER and OER) in aqueous electrolyte solutions. Using a rotating disk electrode (RDE), it is shown that at certain conditions the observed current, i.e., the reaction rate...

  5. Tc-99 Ion Exchange Resin Testing

    Energy Technology Data Exchange (ETDEWEB)

    Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

    2010-08-01

    Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

  6. Application of the hybrid complexation-ultrafiltration process for metal ion removal from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Jianxian [College of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China) and College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)], E-mail: zengjianxian@163.com; Ye Hongqi [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Hu Zhongyu [College of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China)

    2009-01-30

    Complexation-ultrafiltration process was investigated for mercury and cadmium removal from aqueous solutions by using poly(acrylic acid) sodium salt (PAASS) as a complexing agent. The kinetics of complexation reactions of PAASS with the metal ions were studied under a large excess PAASS and pH 5.5. It takes 25 and 50 min for mercury and cadmium to get the complexation equilibrium, respectively, and the reaction kinetics can be described by a pseudo-first-order equation. Effects of various operating parameters such as loading ratios, pH values, etc. on metal rejection coefficients (R) were investigated. In the process of concentration, membrane fluxes decline slowly and R values are about 1. The concentrated retentates were used further for the decomplexation. The decomplexation ratio of mercury-PAASS complex is about 30%, whereas that of cadmium-PAASS complex reaches 93.5%. After the decomplexation, diafiltration experiments were carried out at pH 2.5. Cadmium can be diafiltrated satisfactorily from the retentate, but for mercury it is the contrary. Selective separation of the both metal ions was studied from a binary solution at pH 5. When mercury, cadmium and PAASS concentrations are 30, 30 and 40 mg L{sup -1}, respectively, mercury is retained by ultrafiltration while almost all cadmium passes through the membrane.

  7. Application of the hybrid complexation-ultrafiltration process for metal ion removal from aqueous solutions.

    Science.gov (United States)

    Zeng, Jianxian; Ye, Hongqi; Hu, Zhongyu

    2009-01-30

    Complexation-ultrafiltration process was investigated for mercury and cadmium removal from aqueous solutions by using poly(acrylic acid) sodium salt (PAASS) as a complexing agent. The kinetics of complexation reactions of PAASS with the metal ions were studied under a large excess PAASS and pH 5.5. It takes 25 and 50 min for mercury and cadmium to get the complexation equilibrium, respectively, and the reaction kinetics can be described by a pseudo-first-order equation. Effects of various operating parameters such as loading ratios, pH values, etc. on metal rejection coefficients (R) were investigated. In the process of concentration, membrane fluxes decline slowly and R values are about 1. The concentrated retentates were used further for the decomplexation. The decomplexation ratio of mercury-PAASS complex is about 30%, whereas that of cadmium-PAASS complex reaches 93.5%. After the decomplexation, diafiltration experiments were carried out at pH 2.5. Cadmium can be diafiltrated satisfactorily from the retentate, but for mercury it is the contrary. Selective separation of the both metal ions was studied from a binary solution at pH 5. When mercury, cadmium and PAASS concentrations are 30, 30 and 40 mg L(-1), respectively, mercury is retained by ultrafiltration while almost all cadmium passes through the membrane.

  8. The effect of magnesium ions on dielectric relaxation in semidilute DNA aqueous solutions

    CERN Document Server

    Grgičin, Danijel; Ivek, Tomislav; Tomić, Silvia; Podgornik, Rudi

    2013-01-01

    The effect of magnesium ion Mg2+ on the dielectric relaxation of semidilute DNA aqueous solutions has been studied by means of dielectric spectroscopy. Two dielectric relaxations in the 100 Hz - 100 MHz frequency range, originating in the motion of DNA counterions, were probed as a function of DNA and Mg2+ ion concentration in added MgCl2 salt. The high-frequency mode in the MHz range, stemming from the structural organization of the DNA network, reveals de Gennes-Pfeuty-Dobrynin correlation length as the pertinent fundamental length scale for sufficiently low concentration of added salt. No relaxation fingerprint of DNA denaturation bubbles, leading to exposed hydrophobic core scaling, was detected at low DNA concentrations, thus indicating an increased stability of the double-stranded conformation as compared to the case of DNA solutions with univalent counterions. The presence of Mg2+ does not change qualitatively the low frequency mode in the kHz range correlated with single DNA conformational properties....

  9. Adsorption of indium(III) ions from aqueous solution using chitosan-coated bentonite beads

    Energy Technology Data Exchange (ETDEWEB)

    Calagui, Mary Jane C. [College of Engineering, Cagayan State University, Cagayan Valley 3500 (Philippines); School of Graduate Studies, Mapua Institute of Technology, Manila 1800 (Philippines); Senoro, Delia B. [School of Graduate Studies, Mapua Institute of Technology, Manila 1800 (Philippines); Kan, Chi-Chuan [Institute of Hot Spring Industrial, Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan (China); Salvacion, Jonathan W.L. [School of Graduate Studies, Mapua Institute of Technology, Manila 1800 (Philippines); Futalan, Cybelle Morales [Operations Department, Frontier Oil Corporation, Makati City 1229 (Philippines); Wan, Meng-Wei, E-mail: peterwan@mail.chna.edu.tw [Department of Environmental Engineering and Science, Chia Nan University of Pharmacy and Science, Tainan 71710, Taiwan (China)

    2014-07-30

    Highlights: • A more acidic pH causes a decrease in adsorption capacity. • The kinetic data follow the pseudo-second order equation. • Equilibrium data correlated well with Langmuir isotherm. • Removal of indium is a spontaneous and endothermic process. - Abstract: Batch adsorption study was utilized in evaluating the potential suitability of chitosan-coated bentonite (CCB) as an adsorbent in the removal of indium ions from aqueous solution. The percentage (%) removal and adsorption capacity of indium(III) were examined as a function of solution pH, initial concentration, adsorbent dosage and temperature. The experimental data were fitted with several isotherm models, where the equilibrium data was best described by Langmuir isotherm. The mean energy (E) value was found in the range of 1–8 kJ/mol, indicating that the governing type of adsorption of indium(III) onto CCB is essentially physical. Thermodynamic parameters, including Gibbs free energy, enthalpy, and entropy indicated that the indium(III) ions adsorption onto CCB was feasible, spontaneous and endothermic in the temperature range of 278–318 K. The kinetics was evaluated utilizing the pseudo-first order and pseudo-second order model. The adsorption kinetics of indium(III) best fits the pseudo-second order (R{sup 2} > 0.99), which implies that chemical sorption as the rate-limiting step.

  10. Microscopical characterizations of nanofiltration membranes for the removal of nickel ions from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Agboola, Oluranti; Maree, Jannie; Mbaya, Richard; Kolesnikov, Andrei; Sadiku, Rotimi [Tshwane University of Technology, Pretoria (South Africa); Verliefde, Arne; D' Haese, Arnout [Ghent University, Gent (Belgium)

    2015-04-15

    The nanofiltration (NF) process is electrostatically governed and the surface free energy plays a key role in the separation of particulates, macromolecules, and dissolved ionic species. Streaming potential measurement and the surface charge mapping by Kelvin probe atomic force microscopy (AFM) have been carried out. Forces of interaction near the surface of nanofiltration membranes were further studied by a force spectroscopy using atomic force microscopy. The two membranes used are more negatively charged at high pH values; hence the higher the solution chemistry, the higher and faster will be adhesion of ions on the surface of the nanofiltration membranes. It was observed that the three acquired signals from non-contact AFM (contact potential difference, amplitude and phase) were rigorously connected to the surface structure of the nanofiltration membranes. In addition to the surface structure (roughness), electrostatic interactions can also enhance initial particle adhesion to surfaces of nanofiltration membranes. The performance of the NF membranes was further investigated for the removal of nickel ions from aqueous solution, and the results were correlated to the mechanical responses of the nanofiltration membranes obtained from AFM and the streaming potential measurement.

  11. 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.

  12. Ion aggregation in high salt solutions. III. Computational vibrational spectroscopy of HDO in aqueous salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jun-Ho; Lim, Sohee; Chon, Bonghwan; Cho, Minhaeng, E-mail: mcho@korea.ac.kr [Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science, Seoul 136-713 (Korea, Republic of); Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of); Kim, Heejae; Kim, Seongheun [Department of Chemistry, Korea University, Seoul 136-713 (Korea, Republic of)

    2015-05-28

    The vibrational frequency, frequency fluctuation dynamics, and transition dipole moment of the O—D stretch mode of HDO molecule in aqueous solutions are strongly dependent on its local electrostatic environment and hydrogen-bond network structure. Therefore, the time-resolved vibrational spectroscopy the O—D stretch mode has been particularly used to investigate specific ion effects on water structure. Despite prolonged efforts to understand the interplay of O—D vibrational dynamics with local water hydrogen-bond network and ion aggregate structures in high salt solutions, still there exists a gap between theory and experiment due to a lack of quantitative model for accurately describing O—D stretch frequency in high salt solutions. To fill this gap, we have performed numerical simulations of Raman scattering and IR absorption spectra of the O—D stretch mode of HDO in highly concentrated NaCl and KSCN solutions and compared them with experimental results. Carrying out extensive quantum chemistry calculations on not only water clusters but also ion-water clusters, we first developed a distributed vibrational solvatochromic charge model for the O—D stretch mode in aqueous salt solutions. Furthermore, the non-Condon effect on the vibrational transition dipole moment of the O—D stretch mode was fully taken into consideration with the charge response kernel that is non-local polarizability density. From the fluctuating O—D stretch mode frequencies and transition dipole vectors obtained from the molecular dynamics simulations, the O—D stretch Raman scattering and IR absorption spectra of HDO in salt solutions could be calculated. The polarization effect on the transition dipole vector of the O—D stretch mode is shown to be important and the asymmetric line shapes of the O—D stretch Raman scattering and IR absorption spectra of HDO especially in highly concentrated NaCl and KSCN solutions are in quantitative agreement with experimental results. We

  13. Biosorption of cadmium(Ⅱ) and lead(Ⅱ) ions from aqueous solutions onto dried activated sludge

    Institute of Scientific and Technical Information of China (English)

    WANG Xue-jiang; XIA Si-qing; CHEN Ling; ZHAO Jian-fu; CHOVELON Jean-marc; NICOLE Jaffrezic-renault

    2006-01-01

    The removal of heavy-metal ions from aqueous solutions by using dried activated sludge has been investigated in batch systems. Effect of solution pH, initial metal ion concentration, and temperature were determined. The results of the kinetic studies showed that the uptake processes of the two metal ions(Cd(Ⅱ) and Pb(Ⅱ)) followed the pseudo-second-order rate expression. The equilibrium data fitted very well to both the Langmuir and Freundlich adsorption models. The FT-IR analysis showed that the main mechanism of Cd(Ⅱ) and Pb(Ⅱ) biosorption onto dried activated sludge was their binding with amide I group.

  14. Uptake of Pb(II) ion From Aqueous Solution Using Silk Cotton Hull Carbon: An Agricultural Waste Biomass

    OpenAIRE

    Shanmugavalli, R.; P. S. Syed Shabudeen; R. Venckatesh; K. Kadirvelu; S. Madhavakrishnan; S. Pattabhi

    2006-01-01

    Activated carbon prepared from silk cotton hull (SCH) was used for the adsorptive removal of Pb(II) ion from aqueous solution. The raw material used for the preparation of activated carbon is the waste of agricultural product; the production of this carbon is expected to be economically feasible. Parameters such as agitation time, metal ion concentration, adsorbent dose, pH and Particle size were studied. Adsorption equilibrium was reached within 80 min for 10, 20, 30 and 40mg/l of Pb(II) ion...

  15. Effect of Fe ion concentration on fatigue life of carbon steel in aqueous CO2 environment

    DEFF Research Database (Denmark)

    Rogowska, Magdalena; Gudme, J.; Rubin, A.

    2016-01-01

    of Fe2+ marginally above the solubility limit of FeCO3 compared to the samples tested in highly supersaturated solution of Fe2+. Results revealed that the impact of the alternating stresses on the corrosion behaviour of samples reduces with lowering the applied stresses. At the stress range of 100 MPa......In this work, the corrosion fatigue behaviour of steel armours used in the flexible pipes, in aqueous solutions initially containing different concentrations of Fe2+, was investigated by four-point bending testing under saturated 1 bar CO2 condition. Corrosion fatigue results were supported with ex...... situ measurements of Fe2+ and pH. Characterisation of the corrosion scales and crack formations was performed using microscopic and diffraction techniques. Fatigue results showed two times better fatigue life, at the stress ranges of 250 MPa, for samples tested in solutions containing the concentration...

  16. Adsorption of heavy metal ions from aqueous solution by carboxylated cellulose nanocrystals

    Institute of Scientific and Technical Information of China (English)

    Xiaolin Yu; Shengrui Tong; Maofa Ge; Lingyan Wu; Junchao Zuo; Changyan Cao; Weiguo Song

    2013-01-01

    A novel nanoadsorbent for the removal of heavy metal ions is reported.Cotton was first hydrolyzed to obtain cellulose nanocrystals (CNCs).CNCs were then chemically modified with succinic anhydride to obtain SCNCs.The sodic nanoadsorbent (NaSCNCs) was further prepared by treatment of SCNCs with saturated NaHCO3 aqueous solution.Batch experiments were carried out with SCNCs and NaSCNCs for the removal of Pb2+ and Cd2+.The effects of contact time,pH,initial adsorption concentration,coexisting ions and the regeneration performance were investigated.Kinetic studies showed that the adsorption equilibrium time of Pb2+ and Cd2+ was reached within 150 rain on SCNCs and 5 rain on NaSCNCs.The adsorption capacities of Pb2+ and Cd2+ on SCNCs and NaSCNCs increased with increasing pH.The adsorption isotherm was well fitted by the Langmuir model.The maximum adsorption capacities of SCNCs and NaSCNCs for Pb2+ and Cd2+ were 367.6 mg/g,259.7 mg/g and 465.1 mg/g,344.8 rag/g,respectively.SCNCs and NaSCNCs showed high selectivity and interference resistance from coexisting ions for the adsorption of Pb2+.NaSCNCs could be efficiently regenerated with a mild saturated NaC1 solution with no loss of capacity after two recycles.The adsorption mechanisms of SCNCs and NaSCNCs were discussed.

  17. Removal of mercury(II) ions in aqueous solution using the peel biomass of Pachira aquatica Aubl: kinetics and adsorption equilibrium studies.

    Science.gov (United States)

    Santana, Andrea J; dos Santos, Walter N L; Silva, Laiana O B; das Virgens, Cesário F

    2016-05-01

    Mercury is a highly toxic substance that is a health hazard to humans. This study aims to investigate powders obtained from the peel of the fruit of Pachira aquatica Aubl, in its in natura and/or acidified form, as an adsorbent for the removal of mercury ions in aqueous solution. The materials were characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The infrared spectra showed bands corresponding to the axial deformation of carbonyls from carboxylic acids, the most important functional group responsible for fixing the metal species to the adsorbent material. The thermograms displayed mass losses related to the decomposition of three major components, i.e., hemicellulose, cellulose, and lignin. The adsorption process was evaluated using cold-vapor atomic fluorescence spectrometry (CV AFS) and cold-vapor atomic absorption spectrometry (CV AAS). Three isotherm models were employed. The adsorption isotherm model, Langmuir-Freundlich, best represented the adsorption process, and the maximum adsorption capacity was predicted to be 0.71 and 0.58 mg g(-1) at 25 °C in nature and acidified, respectively. Adsorption efficiencies were further tested on real aqueous wastewater samples, and removal of Hg(II) was recorded as 69.6 % for biomass acidified and 76.3 % for biomass in nature. Results obtained from sorption experiments on real aqueous wastewater samples revealed that recovery of the target metal ions was very satisfactory. The pseudo-second-order model showed the best correlation to the experimental data. The current findings showed that the investigated materials are potential adsorbents for mercury(II) ion removal in aqueous solution, with acidified P. aquatica Aubl being the most efficient adsorbent.

  18. Removal of aqueous cyanide with strongly basic ion-exchange resin.

    Science.gov (United States)

    Simsek, Halis; Kobya, Mehmet; Khan, Eakalak; Bezbaruah, Achintya N

    2015-01-01

    The removal of cyanide (CN-) from aqueous solutions using a strongly basic ion-exchange resin, Purolite A-250, was investigated. The effects of contact time, initial CN- concentration, pH, temperature, resin dosage, agitation speed, and particle size distribution on the removal of CN- were examined. The adsorption equilibrium data fitted the Langmuir isotherm very well. The maximum CN- adsorption capacity of Purolite A-250 was found to be 44 mg CN- g(-1) resin. More than 90% CN- adsorption was achieved for most CN- solutions (50, 100, and 200 mg CN- L(-1)) with a resin dose of 2 g L(-1). The equilibrium time was ∼20 min, optimum pH was 10.0-10.5, and optimum agitation speed was 150 rpm. An increase in adsorption of CN- with increasing resin dosage was observed. Adsorption of CN- by the resin was marginally affected (maximum 4% variation) within an environmentally relevant temperature range of 20-50 °C. Fixed-bed column (20.5 mm internal diameters) experiments were performed to investigate the effects of resin bed depth and influent flow rate on breakthrough behaviour. Breakthrough occurred in 5 min for 0.60 cm bed depth while it was 340 min for 5.40 cm bed depth. Adsorption capacity was 25.5 mg CN- g(-1) for 5 mL min(-1) flow rate and 3.9 mg CN- g(-1) for 20 mL min(-1) flow rate. The research has established that the resin can be effectively used for CN- removal from aqueous solutions.

  19. Removal of Lead(II) Ions from Aqueous Solution Using L. Seed Husk Ash as a Biosorbent.

    Science.gov (United States)

    Shi, Bingfang; Zuo, Weiyuan; Zhang, Jinlei; Tong, Haijuan; Zhao, Jinhe

    2016-05-01

    The removal of heavy metals, especially from wastewater, has attracted significant interest because of their toxicity, tendency to bioaccumulate, and the threat they pose to human life and the environment. Many low-cost sorbents have been investigated for their biosorption capacity toward heavy metals. However, there are no reports available on the removal of Pb(II) from aqueous solution by of L. seed husk ash. In this work, use of seed husk ash for the removal of Pb(II) from wastewater was investigated as a function of contact time and the initial pH of the solution. Kinetics and equilibrium constants were obtained from batch experiments. Our study shows that the adsorption process follows pseudo-second-order kinetics. Moreover, the Langmuir absorption model gave a better fit to the experimental data than the Freundlich equation. The maximum adsorption capacity of the husk ash was 263.10 mg g at 298 K and pH 5.0, and this is higher than the previously reported data obtained using other sorbents. The results obtained confirm that seed husk ash is an effective sorbent for the removal of Pb(II) from aqueous solution. Analysis of infrared spectra of the husk ash after absorption of Pb(II) suggested that OH, C=O, C-O, Si-O-Si, and O-Si-O groups were important for the Pb(II) ion removal. Moreover, practical tests on this biosorbent for Pb(II) removal in real wastewater samples successfully demonstrated that seed husk ash constitutes an efficient and cost-effective technology for the elimination of heavy metals from industrial effluent.

  20. Efficiency of Chitosan for the Removal of Pb (II), Fe (II) and Cu (II) Ions from Aqueous Solutions

    OpenAIRE

    Soheil Sobhanardakani; Raziyeh Zandipak; Hassan Parvizimosaed; Arash Javanshir Khoei; Mehran Moslemi; Mahsa Tahergorabi; Seyed Mehdi Hosseini; Parisa Delfieh

    2014-01-01

    Background: Heavy metals have been recognized as harmful environmental pollutant known to produce highly toxic effects on different organs and systems of both humans and animals. The aim of this paper is to evaluate the adsorption potential of chitosan for the removal of Pb(II), Fe(II) and Cu(II) ions from aqueous solutions. Methods: This study was conducted in laboratory scale. In this paper chitosan has been used as an adsorbent for the removal of Pb(II), Fe(II) and Cu(II) from aqueous s...

  1. Prediction of the pKa's of aqueous metal ion +2 complexes.

    Science.gov (United States)

    Jackson, Virgil E; Felmy, Andrew R; Dixon, David A

    2015-03-26

    Aqueous metal ions play an important role in many areas of chemistry. The acidities of [Be(H2O)4](2+), [M(H2O)6](2+), M = Mg(2+), Mn(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), and Hg(2+), and [M(H2O)n](2+), M = Ca(2+) and Sr(2+), n = 7 and 8, complexes have been predicted using density functional theory, second-order Møller-Plesset perturbation theory (MP2), and coupled cluster CCSD(T) theory in the gas phase. pKa's in aqueous solution were predicted by using self-consistent reaction field (SCRF) calculations with different solvation models. The most common binding motif of the majority of the metal +2 complexes is coordination number (CN) 6, with each hexaaquo cluster having reasonably high symmetry for the best arrangement of the water molecules in the first solvation shell. Be(2+) is tetracoordinated, but a second solvation shell of 8 waters is needed to predict the pKa. The Ca(2+) and Sr(2+) aquo clusters have a coordination number of 7 or 8 as found in terms of the energy of the reaction M(H2O)7(2+) + H2O → M(H2O)8(2+) and the pKa values. The calculated geometries are in reasonable agreement with experiment. The SCRF calculations with the conductor-like screening model (COSMO), and the conductor polarized continuum model (CPCM) using COSMO-RS radii, consistently agree best with experiment at the MP2/aug-cc-pVDZ and CCSD(T)/aug-cc-pVDZ levels of theory. The CCSD(T) level provides the most accurate pKa's, and the MP2 level also provides reliable predictions. Our predictions were used to elucidate the properties of metal +2 ion complexes. The pKa predictions provide confirmation of the size of the first solvation shell sizes. The calculations show that it is still difficult to predict pKa's using this cluster/implicit solvent approach to better than 1 pKa unit.

  2. Fluorometric selective detection of fluoride ions in aqueous media using Ag doped CdS/ZnS core/shell nanoparticles.

    Science.gov (United States)

    Boxi, Siddhartha Sankar; Paria, Santanu

    2016-01-14

    The presence of fluoride ions in drinking water plays an important role in human health. For that reason, maintaining the optimum concentration of fluoride ions in drinking water is essential, as both low and excess (above the permissible level) concentrations can cause different health problems, such as fluorosis, urolithiasis, kidney failure, cancer, and can even lead to death. So, development of a simple and low cost method for the detection of fluoride ions in water is highly desirable. In this study, a fluorometric method based on Ag-CdS/Ag-ZnS core/shell nanoparticles is developed for fluoride ion detection. The method was tested in aqueous solution at different pH values. The selectivity and sensitivity of the fluorescence probe was checked in the presence of other anions (Cl(-), Br(-), I(-), NO3(-) SO4(2-), HCO3(-), HPO4(2-), CH3COO(-), and H2PO4(-)) and found there is no significant interference of these associated ions. The fluoride ion concentration was varied in the range 190-22 800 μg L(-1) and a lower detection limit was obtained as 99.7 μg L(-1).

  3. Thermodynamic study of the adsorption of chromium ions from aqueous solution on waste corn cobs material

    Directory of Open Access Journals (Sweden)

    Rafael A. Fonseca-Correa

    2014-12-01

    Full Text Available The paper shows the results of a study obtaining activated carbon from corn cobs and determining its use as an adsorbent for the removal of Cr3+ from aqueous solutions. The finely ground precursor was subjected to pyrolysis at 600 and 900 °C in a nitrogen atmosphere and chemical activation with H2O2 and HNO3. The effects of pyrolysis conditions and activation method on the physicochemical properties of the materials obtained were tested. The samples were characterised chemically and texturally. Were obtained microporous activated carbons of well-developed surface area varying from 337 to 1213 m2/g and exhibited differences acid-base character of the surface. The results obtained shows that a suitable good option of the activation procedure for corncobs permits the production of economic adsorbents with high sorption capacity for Cr3+ from aqueous solutions. A detailed study of immersion calorimetry was performed with carbons prepared from corn cobs to establish possible relationships with these materials between the enthalpies of immersion and textural and chemical parameters.

  4. Novel kinetic model of the removal of divalent heavy metal ions from aqueous solutions by natural clinoptilolite.

    Science.gov (United States)

    Jovanovic, Mina; Rajic, Nevenka; Obradovic, Bojana

    2012-09-30

    Removal of heavy metal ions from aqueous solutions using zeolites is widely described by pseudo-second order kinetics although this model may not be valid under all conditions. In this work, we have extended approaches used for derivation of this model in order to develop a novel kinetic model that is related to the ion exchange mechanism underlying sorption of metal ions in zeolites. The novel model assumed two reversible steps, i.e. release of sodium ions from the zeolite lattice followed by bonding of the metal ion. The model was applied to experimental results of Cu(II) sorption by natural clinoptilolite-rich zeolitic tuff at different initial concentrations and temperatures and then validated by predictions of ion exchange kinetics of other divalent heavy metal ions (i.e. Mn(II), Zn(II) and Pb(II)). Model predictions were in excellent agreements with experimental data for all investigated systems. In regard to the proposed mechanism, modeling results implied that the sodium ion release rate was constant for all investigated metals while the overall rate was mainly determined by the rate of heavy metal ion bonding to the lattice. In addition, prediction capabilities of the novel model were demonstrated requiring one experimentally determined parameter, only.

  5. Nickel Hexacyanoferrate Nanoparticle Electrodes For Aqueous Sodium and Potassium Ion Batteries

    KAUST Repository

    Wessells, Colin D.

    2011-12-14

    The electrical power grid faces a growing need for large-scale energy storage over a wide range of time scales due to costly short-term transients, frequency regulation, and load balancing. The durability, high power, energy efficiency, and low cost needed for grid-scale storage pose substantial challenges for conventional battery technology.(1, 2)Here, we demonstrate insertion/extraction of sodium and potassium ions in a low-strain nickel hexacyanoferrate electrode material for at least five thousand deep cycles at high current densities in inexpensive aqueous electrolytes. Its open-framework structure allows retention of 66% of the initial capacity even at a very high (41.7C) rate. At low current densities, its round trip energy efficiency reaches 99%. This low-cost material is readily synthesized in bulk quantities. The long cycle life, high power, good energy efficiency, safety, and inexpensive production method make nickel hexacyanoferrate an attractive candidate for use in large-scale batteries to support the electrical grid. © 2011 American Chemical Society.

  6. Adsorption of Lead Ions from Aqueous Solutions Using Gamma Irradiated Minerals

    Directory of Open Access Journals (Sweden)

    Julián Cruz-Olivares

    2016-01-01

    Full Text Available For the first time, an irradiated mineral was used as a novel modified adsorbent for lead removal of aqueous solutions. The effects of gamma radiation doses and temperature on the lead adsorption capacity of an unknown mineral were evaluated. The results show that, in the chemisorption process, the highest adsorption capacity (9.91 mg/g and the maximum percentage of lead removal (99.1% were reached at 40°C when using an irradiated mineral at 150 kGy. The improvement on the lead adsorption speed was the most important feature of the irradiated mineral. The experimental results were successfully correlated with the pseudo second-order kinetic model. For all results, the average absolute relative deviations (AARD were less than 13.20%, and the correlation factor (r2 was higher than 0.998. Moreover, the average values of the thermodynamic parameters (ΔG0=-10612 J/mol, ΔH0=-12360 J/mol, and ΔS0=171 J/mol K suggest the feasibility of the proposed process, in terms of the endothermic and irreversible chemisorption results; moreover, ion exchange was evaluated through the EDS results. The X-ray diffraction analysis showed that the unknown irradiated mineral is mainly composed of quartz (SiO2, calcite (CaCO3, and calcium magnesium silicate (Ca0.15Mg0.85 Mg (SiO6.

  7. Influence of ions on the coagulation and removal of fullerene in aqueous phase.

    Science.gov (United States)

    Zhang, Lizhu; Zhao, Qing; Wang, Shutao; Mashayekhi, Hamid; Li, Xin; Xing, Baoshan

    2014-01-01

    Increased attention has been paid to the transportation and removal efficiencies of nanoparticles during water treatment. Here, C₆₀ was selected as nano-pollutant to investigate its removal efficiency in the process of coagulation by Al(3+) in regard to different ions. Negatively charged C₆₀ tends to adsorb hydrated Al(3+) to form positively charged C₆₀-Al(OH)(n)((m-δ)+) particles, leading to the restabilization of C₆₀. Multivalent anions, i.e., CO₃(2-), SO₄(2-), HPO₄(2-),and humic acid (HA), were shown to bridge the C₆₀-Al (OH)(n)((m-δ)+) particles together and induce the formation of flocs, resulting in enhanced C₆₀ removal (>80%). Monovalent anions, such as OH(-), NO₃(-) and the surfactant SDS, were not able to bridge the C₆₀-Al (OH)(n)((m-δ)+) particles together; hence, they had no effect on the C₆₀ removal. The addition of Na(+) and Ca(2+) increased the ionic strength of the aqueous solution, which compressed the electric double layer and induced the C₆₀-Al(OH)(n)((m-δ)+) particles to aggregate. However, they are not the essential factors for flocs formation. This is the first study to report the bridging phenomena between multivalent anions and C₆₀-Al(OH)(n)((m-δ)+) in water treatments, and it highlights that the presence of multivalent anions and cations in raw water are important for the effective removal of C₆₀.

  8. Removal of Pb(II) ions from aqueous solution by adsorption using bael leaves (Aegle marmelos).

    Science.gov (United States)

    Chakravarty, S; Mohanty, Ashok; Sudha, T Nag; Upadhyay, A K; Konar, J; Sircar, J K; Madhukar, A; Gupta, K K

    2010-01-15

    Biosorption of Pb(II) on bael leaves (Aegle marmelos) was investigated for the removal of Pb(II) from aqueous solution using different doses of adsorbent, initial pH, and contact time. The maximum Pb loading capacity of the bael leaves was 104 mg g(-1) at 50 mg L(-1) initial Pb(II) concentration at pH 5.1. SEM and FT-IR studies indicated that the adsorption of Pb(II) occurs inside the wall of the hollow tubes present in the bael leaves and carboxylic acid, thioester and sulphonamide groups are involved in the process. The sorption process was best described by pseudo second order kinetics. Among Freundlich and Langmuir isotherms, the latter had a better fit with the experimental data. The activation energy E(a) confirmed that the nature of adsorption was physisorption. Bael leaves can selectively remove Pb(II) in the presence of other metal ions. This was demonstrated by removing Pb from the effluent of exhausted batteries.

  9. An all-organic non-aqueous lithium-ion redox flow battery

    Energy Technology Data Exchange (ETDEWEB)

    Brushett, Fikile R.; Vaughey, John T.; Jansen, Andrew N. [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2012-11-15

    A non-aqueous lithium-ion redox flow battery employing organic molecules is proposed and investigated. 2,5-Di-tert-butyl-1,4-bis(2-methoxyethoxy)benzene and a variety of molecules derived from quinoxaline are employed as initial high-potential and low-potential active materials, respectively. Electrochemical measurements highlight that the choice of electrolyte and of substituent groups can have a significant impact on redox species performance. The charge-discharge characteristics are investigated in a modified coin-cell configuration. After an initial break-in period, coulombic and energy efficiencies for this unoptimized system are {proportional_to}70% and {proportional_to}37%, respectively, with major charge and discharge plateaus between 1.8-2.4 V and 1.7-1.3 V, respectively, for 30 cycles. Performance enhancements are expected with improvements in cell design and materials processing. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Speciation of phytate ion in aqueous solution Thermodynamic parameters for protonation in NaCl

    Energy Technology Data Exchange (ETDEWEB)

    De Stefano, Concetta; Milea, Demetrio; Sammartano, Silvio

    2004-12-01

    Phytate protonation enthalpies and entropies were determined by direct calorimetric titrations, in sodium chloride aqueous media at different ionic strengths (0.1{<=}I/mol L{sup -1}{<=}1) and at t=25 deg. C. Only the first seven protonation steps were taken into account, since the remaining five protons of phytic acid could be considered as 'strongly acidic' (log K{sub i}{sup H}{<=}1, 8{<=}i{<=}12). The analysis of results evidenced slight variations among enthalpy and entropy values, for the same protonation step (i), at different ionic strengths. T{delta}S{sub i} values for each protonation step are significantly higher than the corresponding enthalpy changes, revealing the entropic nature of the bond involved in phytate protonation. The enthalpy changes for phytate protonation generally increase for each protonation step, as typical for phosphate ligands. Dependence on ionic strength for both log K{sub i}{sup H} and {delta}H{sub i} was taken into account by Specific ion Interaction Theory (SIT). Useful predictive relationships for the dependence of T{delta}S on {delta}G and on protonation step 'i' were proposed.

  11. Reusable fluorescent photocrosslinked polymeric sensor for determining lead ions in aqueous media

    Science.gov (United States)

    Çubuk, Soner; Taşci, Neşe; Kahraman, Memet Vezir; Bayramoğlu, Gülay; Yetimoğlu, Ece Kök

    2016-04-01

    In this study, 1-vinylimidazole units bearing photocured films were prepared as fluorescent sensors towards Pb2 + in aqueous solutions. The influence of experimental parameters such as pH, time and foreign ion concentrations were investigated. Sensor response was linear over a concentration range of 4.83 × 10- 8 to 4.83 × 10- 7 mol L- 1. The sensor was highly sensitive with a detection limit as low as 1.87 × 10- 8 mol L- 1, and having a selectivity of over four thousand fold. The response time of the sensor was found to be 5 min. When stored in a desiccator at room temperature the sensor showed good stability after a 5 month period. The fluorescence sensors were successful in the determination of Pb2 + in water samples as well as in the determination of the quantitative amount of lead and the results were satisfying. Compared with previously reported literature, the prepared new sensor is highly sensitive and selective.

  12. Removal of copper, nickel and zinc ions from aqueous solution by chitosan-8-hydroxyquinoline beads

    Energy Technology Data Exchange (ETDEWEB)

    Barros, Francisco C.F.; Dias, Francisco S.; Vasconcellos, Luiz C.G. [Departamento de Quimica Organica e Inorganica, Campus do Pici - Universidade Federal do Ceara, Fortaleza (Brazil); Sousa, Francisco W. [Departamento de Engenharia Hidraulica e Ambiental, Campus do Pici - Universidade Federal do Ceara, Fortaleza (Brazil); Cavalcante, Rivelino M.; Carvalho, Tecia V.; Queiroz, Danilo C. [Departamento de Quimica Analitica e Fisico Quimica, Campus do Pici - Universidade Federal do Ceara, Fortaleza (Brazil); Nascimento, Ronaldo F.

    2008-03-15

    In this work, 8-hydroxyquinoline is used as the active sites in cross-linked chitosan beads with epichlorohydrin (CT-8HQ). The CT-8HQ material was shaped in bead form and used for heavy metal removal from aqueous solution. The study was carried out at pH 5.0 with both batch and column methods and the maximum adsorption capacity of metal ions by the CT-8HQ was attained in 4 h in the batch experiment. The adsorption capacity order was: Cu{sup 2+} > Ni{sup 2+} > Zn{sup 2+} for both mono- and multi-component systems with batch conditions. From breakthrough curves with column conditions, the adsorption capacity followed the order Cu{sup 2+} > Zn{sup 2+} > Ni{sup 2+} for both mono- and multi-component systems. The CT-8HQ beads maintained good metal adsorption capacity for all five cycles with absorbent restoration achieved with the use of 1.0 mol L{sup -1} HCl solution, with 90% regeneration. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  13. Adsorption ability of the carbon black for nickel ions uptake from aqueous solution

    Directory of Open Access Journals (Sweden)

    Rađenović Ankica

    2013-01-01

    Full Text Available Surface modification can be performed by adsorption of certain organic compounds on the surface of carbon. The main objective of this work was to compare the adsorption ability of acid-modified carbon black with the non-modified one. Modification process was performed by adsorption of acetic acid onto commercial carbon black surface. A batch adsorption system was applied to study the both adsorption reaction, acetic acid and Ni(II adsorption onto the carbon black. Adsorption isotherms of acetic acid and Ni(II adsorption onto the non-modified and modified carbon black were fitted by classical adsorption models, such as Freundlich and Langmuir models. Modified carbon black surface become more active for Ni(II ions removal from aqueous solutions. The results showed that modification by acetic acid increases the adsorption capacity of carbon black from 18.3823 mg Ni(II g-1 to 86.9566 mg Ni(II g-1. SEM analysis enabled the observation of any surface changes in the carbon black that have occurred due to either acid modification or Ni(II adsorption.

  14. Separation of 1,3-Propanediol from Aqueous Solutions by Ion Exchange Chromatography

    Directory of Open Access Journals (Sweden)

    Rukowicz Beata

    2014-06-01

    Full Text Available 1,3-propanediol is a promising monomer with many applications and can be produced by bioconversion of renewable resources. The separation of this product from fermentation broth is a difficult task. In this work, the application of cation exchange resin for the separation of 1,3-propanediol from model aqueous solution was examined. The best effect of separation of 1,3-propanediol from glycerol using sorption method was obtained for H+ resin form, although the observed partition coefficient of 1,3-propanediol was low. On the basis of the results of the sorption of 1,3-propanediol, the ionic forms of the resin were selected and used in the next experiments (H+, Ca2+, Ag+, Na+, Pb2+, Zn2+. The best results in ion exchange chromatography were obtained for cation exchange resin in H+ and Ca2+ form. The use of smaller particle size of resin and a longer length of the column allows to obtain better separation of mixtures.

  15. DNA degradation by aqueous extract of Aloe vera in the presence of copper ions.

    Science.gov (United States)

    Naqvi, Shoa; Ullah, M F; Hadi, S M

    2010-06-01

    The plant Aloe vera has long been used in medicine, as dietary supplements and for cosmetic purposes. Aloe vera extracts are a rich source of polyphenols, such as aloin and aloe emodin and have shown a wide range of pharmacological properties, including anti-inflammatory and anti-cancer properties. The bioactive component aloe emodin has been reported to induce apoptosis in various cancer cell lines. Many of the biological activities of Aloe vera have been attributed to its antioxidant properties. However, most plant-derived polyphenols that are also present in Aloe vera may exhibit pro-oxidant properties either alone or in the presence of transition metals, such as copper. Previous reports from this laboratory have implicated the pro-oxidant action as one of the mechanisms for their anti-cancer properties. In the present paper, we show that aqueous extract of Aloe vera is also able to cause DNA degradation in the presence of copper ions. Further, the extract is also able to reduce Cu(II) to Cu(I) and generate reactive oxygen species, such as superoxide anion and hydroxyl radicals in a dose-dependent manner, which correlates with ability of the extract to cause DNA breakage. Thus, the study shows that in addition to antioxidant activity, Aloe vera extract also possess pro-oxidant properties, leading to oxidative DNA breakage.

  16. Bach Adsorption Study for the Extraction of Silver Ions by Hydrazone Compounds from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Abdussalam Salhin Mohamad Ali

    2012-01-01

    Full Text Available Sorbent materials based on a hydrazone Schiff base compound, C14H11BrN4O4, were prepared either by immobilizing the ligand into sol-gel (SG1 or bonding to silica (SG2. The sorbent materials were characterized by FT-IR, EDX, SEM, TEM, and TGA. The sorption characteristics of a matrix of eight transition metal ions (Ag+, Cu2+, Co2+, Ni2+, Fe3+, Pb2+, Zn2+, and Mn2+ using batch method were studied. Several key parameters that affected the extraction efficiency such as pH, contact time, metal ions concentration, and gel size (for SGl were investigated and optimized. Under the optimized conditions, the physically immobilized hydrazone sorbent (SG1 exhibits highest selectivity towards Ag+ ions, while the chemically bonded hydrazone sorbent (SG2 exhibits high extraction for all metal ions tested. However, for practical applications such as the removal and preconcentration of Ag+, the physically immobilized sorbent (SG1 is preferred.

  17. CSNS H^- ion source test stand

    Institute of Scientific and Technical Information of China (English)

    吴小兵; 张俊嵩; 张华顺; 赵富祥; 欧阳华甫; 池云龙; 何伟; 黄涛; 李刚; 刘应满; 卢艳华; 徐韬光

    2011-01-01

    The Penning surface plasma source is adopted as the China Spallation Neutron Source (CSNS) H^- ion source. The designed energy and beam current of the source are 50 keV and 20 mA, respectively, with a normalized root mean square (norm. rms.) emittance of

  18. Fabrication of a green porous lignin-based sphere for the removal of lead ions from aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhili; Ge, Yuanyuan, E-mail: geyy@gxu.edu.cn; Wan, Liang

    2015-03-21

    Highlights: • A porous lignin-based sphere was prepared from lignosulfonate by a gelation method. • The porous lignin-based sphere (PLS) had a high porosity and pore volume. • The PLS showed high adsorption efficiency for lead ions from aqueous media. • Bed column test proved the potential of PLS for continuous treatment of effluent. - Abstract: A green porous lignin-based sphere (PLS) had been fabricated by a feasible gelation-solidification method from lignosulfonate cross-linked with sodium alginate and epichlorohydrin. The prepared sphere was characterized by Fourier transform infrared spectrometry, scanning electron microscopy, mercury intrusion porosimetry, and thermo gravimetric analysis. The results demonstrated the PLS had a large amount of mesopores (d = 20.7 nm) with a high porosity of 87.66% and a total pore volume of 0.416 cm{sup 3}/g. Batchwise adsorption experiments indicated the PLS possessed excellent adsorption efficiency (95.6 ± 3.5%) for lead ions at an initial concentration of 25.0 mg/L. The adsorption process could be well fitted by intra-particle diffusion model and Langmuir isotherm model. Application of the PLS in bed column mode for the continuous treatment of lead solution exhibited prolonged breakthrough time from 75 min to 100 min as the bed column heights increased from 0.5 cm to 2.5 cm which was much better than the alkaline lignin column (2.5 cm height, breakthrough time = 60 min). The results strongly suggested the high possibility of the porous sphere being applied for the continuous treatment of heavy metals rich wastewater in industry.

  19. Optimization and adsorption kinetic studies of aqueous manganese ion removal using chitin extracted from shells of edible Philippine crabs

    Science.gov (United States)

    Quimque, Mark Tristan J.; Jimenez, Marvin C.; Acas, Meg Ina S.; Indoc, Danrelle Keth L.; Gomez, Enjelyn C.; Tabuñag, Jenny Syl D.

    2017-01-01

    Manganese is a common contaminant in drinking water along with other metal pollutants. This paper investigates the use of chitin, extracted from crab shells obtained as restaurant throwaway, as an adsorbent in removing manganese ions from aqueous medium. In particular, this aims to optimize the adsorption parameters and look into the kinetics of the process. The adsorption experiments done in this study employed the batch equilibration method. In the optimization, the following parameters were considered: pH and concentration of Mn (II) sorbate solution, particle size and dosage of adsorbent chitin, and adsorbent-adsorbate contact time. At the optimal condition, the order of the adsorption reaction was estimated using kinetic models which describes the process best. It was found out that the adsorption of aqueous Mn (II) ions onto chitin obeys the pseudo-second order model. This model assumes that the adsorption occurred via chemisorption

  20. The Kinetic Aspects of the Interaction of Nitrite Ions with Sulfanilic Acid and 1-Naphthylamine in Aqueous and Micellar Media

    Science.gov (United States)

    Korneeva, O. I.; Chernova, R. K.; Doronin, S. Yu.

    2008-04-01

    The kinetics of the reaction of nitrite ions with sulfanilic acid and 1-naphthylamine in aqueous and micellar (sodium dodecyl sulfate) media was studied step-by-step. The diazotization of sulfanilic acid with the nitrite ion was found to occur virtually instantaneously. Anionic surfactant micelles did not influence the rate of this reaction. The calculated effective rate constants and activation energies of the azo coupling reaction between synthesized sulfophenyldiazonium and 1-naphthylamine showed that the passage from water into the micellar medium decelerated the reaction. It was found that sodium dodecyl sulfate micelles played the role of a reagent separator.

  1. Sodium Chloride interaction with solvated and crystalline cellulose : sodium ion affects the tetramer and fibril in aqueous solution

    OpenAIRE

    Bellesia, Giovanni; Gnanakaran, S.

    2013-01-01

    Inorganic salts are a natural component of biomass which have a significant effect on the product yields from a variety of biomass conversion processes. Understanding their effect on biomass at the microscopic level can help discover their mechanistic role. We present a study of the effect of aqueous sodium chloride (NaCl) on the largest component of biomass, cellulose, focused on the thermodynamic and structural effect of a sodium ion on the cellulose tetramer, and fibril. Replica exchange m...

  2. ADSORPTION OF Pb2+ IONS FROM AQUEOUS SOLUTIONS ONTO BAEL TREE LEAF POWDER: ISOTHERMS, KINETICS AND THERMODYNAMICS STUDY

    Directory of Open Access Journals (Sweden)

    P. SENTHIL KUMAR

    2009-12-01

    Full Text Available In this study, bael tree (BT leaf powder was used as an adsorbent for removal of Pb2+ ions from aqueous solutions through batch equilibrium technique. The influence of pH, equilibrium time, temperature, adsorbent dosage and initial concentration of metal ions on adsorbed amount of metals ions were investigated. Studies showed that the pH of aqueous solutions affected Pb2+ ions removal as a result of removal efficiency increased with increasing solution pH. The experimental isotherm data were analyzed using the Langmuir, Freundlich, Temkin and Dubinin-Radushkevich equations. The monolayer adsorption capacity is 4.065 mg/g with the correlation coefficient of 0.993. The experiments showed that highest removal rate was 84.93% at solution pH 5, contact time 60 min and initial concentration of 50 mg/L. Thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy have also been evaluated and it has been found that the sorption process was feasible, spontaneous and exothermic in nature. Three simplified kinetic models including a pseudo-first-order equation, pseudo-second-order equation and intraparticle diffusion equation were selected to follow the adsorption process. Kinetic parameters, rate constants, equilibrium sorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was shown that the adsorption of Pb2+ ions could be described by the pseudo-second order equation, suggesting that the adsorption process is presumable a chemisorption.

  3. Uptake of Pb(II ion From Aqueous Solution Using Silk Cotton Hull Carbon: An Agricultural Waste Biomass

    Directory of Open Access Journals (Sweden)

    R. Shanmugavalli

    2006-01-01

    Full Text Available Activated carbon prepared from silk cotton hull (SCH was used for the adsorptive removal of Pb(II ion from aqueous solution. The raw material used for the preparation of activated carbon is the waste of agricultural product; the production of this carbon is expected to be economically feasible. Parameters such as agitation time, metal ion concentration, adsorbent dose, pH and Particle size were studied. Adsorption equilibrium was reached within 80 min for 10, 20, 30 and 40mg/l of Pb(II ion with 50mg of carbon per mL of solution. Adsorption parameters were determined using both Langmuir and Freundlich isotherm models. The adsorption efficiency reached 100% for 20, 30 and 40mg/l of Pb(II ion with 120, 140 and 150mg of carbon. Pb(II ion removal increased as the pH increased from 2 to 5 and remains constant up to pH 10. Desorption studies were also carried out with dilute hydrochloric acid to know the mechanism of adsorption. Quantitative desorption of Pb(II ion from carbon indicates that adsorption of metal ion is by ion-exchange. Efficiency of the adsorption of SCH was also studied with Pb containing industrial wastewater by varying pH and carbon concentration.

  4. Effect of Cr(VI) concentration on gas and particle production during iron oxidation in aqueous solutions containing Cl(-) ions.

    Science.gov (United States)

    Ahn, Hyangsig; Jo, Ho Young; Ryu, Ji-Hun; Koh, Yong-Kwon

    2017-02-01

    Zero-valent iron (ZVI) is commonly used as a medium in permeable reactive barriers (PRBs) because of its high reducing ability. The generation of H2 gas in PRBs, however, can decrease the permeability of PRBs and reduce the contact area between the PRB and contaminated groundwater. This study investigated the effect of the initial Cr(VI) concentration ([Cr(VI)init]) in aqueous solutions containing Cl(-) ions on the generation of H2 gas. ZVI chips were reacted in reactors with 0.5-M NaCl solutions with [Cr(VI)init] ranging between 51 and 303 mg/L. The initial pH was set at 3. The oxidation of ZVI chips by Cr(VI) in aqueous solutions containing Cl(-) ions produced H2 gas and particles (Fe(III)-Cr(III)(oxy)hydroxides). The Cr(VI) removal from aqueous solutions increased as the [Cr(VI)init] increased, as did H2 gas generation. The positive effect of [Cr(VI)init] on H2 gas generation might be due to an increase in the redox potential gradient as [Cr(VI)init] increases. This increased gradient would enhance H(+) ion penetration through the passive film (Fe(III)-Cr(III)(oxy)hydroxides), which formed on the ZVI surface, by diffusion from the solution to pits beneath the passive film.

  5. Solvent extraction-separation of La(III), Eu(III) and Er(III) ions from aqueous chloride medium using carbamoyl-carboxylic acid extractants

    Institute of Scientific and Technical Information of China (English)

    Reyhaneh Safarbali; Mohammad Reza Yaftian; Abbasali Zamani

    2016-01-01

    N,N-dibutyldiglycol amic acid (HLI) and N,N-dioctyldiglycol amic acid (HLI) were synthesized and characterized by con-ventional spectroscopic methods. These molecules were examined as extractants for extraction-separation of La(III), Eu(III) and Er(III), as representative ions of light, middle and heavy rare earths, from aqueous chloride solutions. The analysis of the extraction equilibria revealed that the extracted species of lanthanum and europium ions by both of the extractants had a 1:3 metal to ligand ratio. It was suggested that erbium ions were extracted into the organic phase via the formation of Er(LI or I)2Cl complexes. The effect of the organic diluents on the extraction-separation efficiency of the studied rare earths by HLI and HLI was investigated by comparing the results obtained in dichloromethane and carbon tetrachloride. Regardless to the diluent used, the order of selectivity presented by the investigated extractants was Er(III)>Eu(III)>La(III). It is noteworthy that, a significant enhancement in separation of the studied rare earths by the extractants was achieved in their competitive extraction experiments with respect to that obtained in single component extraction experiments. Applicability of the extractants for the removal of rare earth ions from spent Ni-MH batteries was tested by removal of La(III), Eu(III) and Er(III) ions from simulated leach solution of such batteries.

  6. Water-soluble polymers for recovery of metal ions from aqueous streams

    Science.gov (United States)

    Smith, Barbara F.; Robison, Thomas W.

    1998-01-01

    A process of selectively separating a target metal contained in an aqueous solution by contacting the aqueous solution containing a target metal with an aqueous solution including a water-soluble polymer capable of binding with the target metal for sufficient time whereby a water-soluble polymer-target metal complex is formed, and, separating the solution including the water-soluble polymer-target metal complex from the solution is disclosed.

  7. Effects of ion concentration on the hydrogen bonded structure of water in the vicinity of ions in aqueous NaCl solutions

    Indian Academy of Sciences (India)

    A Nag; D Chakraborty; A Chandra

    2008-01-01

    Molecular dynamics simulations of dilute and concentrated aqueous NaCl solutions are carried out to investigate the changes of the hydrogen bonded structures in the vicinity of ions for different ion concentrations. An analysis of the hydrogen bond population in the first and second solvation shells of the ions and in the bulk water is done. Although essentially no effect of ions on the hydrogen bonding is observed beyond the first solvation shell of the ions for the dilute solutions, for the concentrated solutions a noticeable change in the average number of water-water hydrogen bonds is observed in the second solvation shells of the ions and even beyond. However, the changes in the average number of hydrogen bonds are found to be relatively less when both water-water and ion-water hydrogen bonds are counted. Thus, the changes in the total number of hydrogen bonds per water are not very dramatic beyond the first solvation shell even for concentrated solutions.

  8. Direct Fluorescence Sensing of Metal Ions in Aqueous Solution Using Intramolecular Charge Transfer Emission from Aggregates of Pentaerythrityl Tetra(p-dimethylaminobenzoate)

    Institute of Scientific and Technical Information of China (English)

    Zhen Chang WEN; Yun Bao JIANG

    2004-01-01

    Pentaerythrityl tetra(p-dimethylaminobenzoate) (PTDMAB) was synthesized and shown to emit in water-rich aqueous dioxane solutions the intramolecular charge transfer fluorescence that was sensitive to the presence of metal ions.

  9. A facile approach for cupric ion detection in aqueous media using polyethyleneimine/PMMA core-shell fluorescent nanoparticles

    Science.gov (United States)

    Chen, Jian; Zeng, Fang; Wu, Shuizhu; Su, Junhua; Zhao, Jianqing; Tong, Zhen

    2009-09-01

    A facile approach was developed to produce a dye-doped core-shell nanoparticle chemosensor for detecting Cu2+ in aqueous media. The core-shell nanoparticle sensor was prepared by a one-step emulsifier-free polymerization, followed by the doping of the fluorescent dye Nile red (9-diethylamino- 5H-benzo[alpha] phenoxazine-5-one, NR) into the particles. For the nanoparticles, the hydrophilic polyethyleneimine (PEI) chain segments serve as the shell and the hydrophobic polymethyl methacrylate (PMMA) constitutes the core of the nanoparticles. The non-toxic and biocompatible PEI chain segments on the nanoparticle surface exhibit a high affinity for Cu2+ ions in aqueous media, and the quenching of the NR fluorescence is observed upon binding of Cu2+ ions. This makes the core-shell nanoparticle system a water-dispersible chemosensor for Cu2+ ion detection. The quenching of fluorescence arises through intraparticle energy transfer (FRET) from the dye in the hydrophobic PMMA core to the Cu2+/PEI complexes on the nanoparticle surface. The energy transfer efficiency for PEI/PMMA particles with different diameters was determined, and it is found that the smaller nanoparticle sample exhibits higher quenching efficiency, and the limit for Cu2+ detection is 1 µM for a nanoparticle sample with a diameter of ~30 nm. The response of the fluorescent nanoparticle towards different metal ions was investigated and the nanoparticle chemosensor displays high selectivity and antidisturbance for the Cu2+ ion among the metal ions examined (Na+, K+, Mg2+, Ca2+, Zn2+, Hg2+, Mn2+, Fe2+, Ni2+, Co2+ and Pb2+). This emulsifier-free, biocompatible and sensitive fluorescent nanoparticle sensor may find applications in cupric ion detection in the biological and environmental areas.

  10. Batch adsorption of cadmium ions from aqueous solution by means of olive cake

    Energy Technology Data Exchange (ETDEWEB)

    Al-Anber, Zaid Ahmed [Al-Balqa Applied University, Faculty of Engineering Technology, Chemical Engineering Department, P.O. Box 15008, Amman 11131 (Jordan)], E-mail: z_alanber@yahoo.com; Matouq, Mohammed Abu Dayeh [Al-Balqa Applied University, Faculty of Engineering Technology, Chemical Engineering Department, P.O. Box 15008, Amman 11131 (Jordan)

    2008-02-28

    The use of natural adsorbent such as olive cake to replace expensive imported synthetic adsorbent is particularly appropriate for developing countries such as Jordan. In this study, batch adsorption experiments were carried out for the removal of cadmium ions from its aqueous solution using olive cake as adsorbent. Parameters effects such as temperature, pH and adsorbent dose on the adsorption process were studied. The adsorbent used in this study exhibited as good sorption at approximately pH 6 at temperatures 28, 35 and 45 deg. C. The removal efficiency was found to be 66% at pH 6 and temperature 28 deg. C. The equilibrium data were analyzed using Langmuir and Freundlich isotherm models to calculate isotherm constants. The experimental results were in a good agreement with these models. Results show that when an increasing in temperature from 28 to 45 deg. C, the maximum adsorption capacity (q{sub max}) is decreased from 65.4 to 44.4 mg/g and Freundlich constant (K{sub f}) decreased from 19.9 to 15.7. The thermodynamic parameters for the adsorption process data were evaluated using Langmuir isotherm. The free energy change ({delta}G{sup o}) and the enthalpy change ({delta}H{sup o}) showed that the process was feasible and exothermic, respectively. The dynamic data fitted to the first order, Lagergren-first order and pseudo second-order kinetic models. The experimental results indicated that the pseudo second-order reaction model provided the best description for these data with a correlation coefficient of 0.99. The adsorption rate constant was calculated as 8.4 x 10{sup -3} g mg{sup -1} min{sup -1} at 28 deg. C.

  11. DEVELOPMENT OF PROTOTYPE TITANATE ION EXCHANGE LOADED MEMBRANES FOR STRONTIUM, CESIUM AND ACTINIDE DECONTAMINATION FROM AQUEOUS MEDIA

    Energy Technology Data Exchange (ETDEWEB)

    Oji, L; Keisha Martin, K; David Hobbs, D

    2008-05-30

    We have successfully incorporated high surface area particles of titanate ion exchange materials (monosodium titanate and crystalline silicotitanate) with acceptable particle size distribution into porous and inert support membrane fibrils consisting of polytetrafluoroethylene (Teflon{reg_sign}), polyethylene and cellulose materials. The resulting membrane sheets, under laboratory conditions, were used to evaluate the removal of surrogate radioactive materials for cesium-137 and strontium-90 from high caustic nuclear waste simulants. These membrane supports met the nominal requirement for nonchemical interaction with the embedded ion exchange materials and were porous enough to allow sufficient liquid flow. Some of this 47-mm size stamped out prototype titanium impregnated ion exchange membrane discs was found to remove more than 96% of dissolved cesium-133 and strontium-88 from a caustic nuclear waste salt simulants. Since in traditional ion exchange based column technology monosodium titanate (MST) is known to have great affinity for the sorbing of other actinides like plutonium, neptunium and even uranium, we expect that the MST-based membranes developed here, although not directly evaluated for uptake of these three actinides because of costs associated with working with actinides which do not have 'true' experimental surrogates, would also show significant affinity for these actinides in aqueous media. It was also observed that crystalline silicotitanate impregnated polytetrafluoroethylene or polyethylene membranes became less selective and sorbed both cesium and strontium from the caustic aqueous salt simulants.

  12. Degradation of trichloroethylene in aqueous solution by calcium peroxide activated with ferrous ion.

    Science.gov (United States)

    Zhang, Xiang; Gu, Xiaogang; Lu, Shuguang; Miao, Zhouwei; Xu, Minhui; Fu, Xiaori; Qiu, Zhaofu; Sui, Qian

    2015-03-02

    The application of calcium peroxide (CaO2) activated with ferrous ion to stimulate the degradation of trichloroethylene (TCE) was investigated. The experimental results showed that TCE could be completely degraded in 5 min at a CaO2/Fe(II)/TCE molar ratio of 4/8/1. Probe compound tests demonstrated the presence of reactive oxygen species HO· and O2(-·) in CaO2/Fe(II) system, while scavenging tests indicated that HO· was the dominant active species responsible for TCE removal, and O2(-·) could promote TCE degradation in CaO2/Fe(II) system. In addition, the influences of initial solution pH and solution matrix were evaluated. It suggested that the elevation of initial solution pH suppressed TCE degradation. Cl(-) had significant scavenging effect on TCE removal, whereas HCO3(-) of high concentration showed favorable function. The influences of NO3(-) and SO4(2-) could be negligible, while natural organic matter (NOM) had a negative effect on TCE removal at a relatively high concentration. The results demonstrated that the technique of CaO2 activated with ferrous ion is a highly promising technique in in situ chemical oxidation (ISCO) remediation in TCE contaminated sites.

  13. Fabrication of Chitosan-complexed Electrode and Evaluation of Its Efficiency in Removal of Copper Ion from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Yoon Young-Chan

    2016-01-01

    Full Text Available In this study, we fabricated chitosan/PVA/activated carbon complexed electrode to remove copper ion from aqueous solution. The prepared composite electrode was analyzed by BET and SEM to investigate its physicochemical properties. Electrochemical properties of prepared composite electrodes were analyzed via cyclic voltammetry. Adsorption performance of copper ion on chitosan composite complexed electrodes was evaluated. Almost similar pore size distribution results were observed in the series of ACP not included electrodes while observed differences in pore size distribution for the ACP included one. Cyclic voltammetry results exhibited that oxidation-reduction reaction does not occur in a potential range of -1.0 ~ 1.0 V. The amount of copper ion during adsroption reaction is increase according to increase of adsorption potential to 1.0 V.

  14. An interesting spectroscopic method for chromofluorogenic detection of cyanide ion in aqueous solution: Disruption of intramolecular charge transfer (ICT)

    Indian Academy of Sciences (India)

    Abdolhamid Alizadeh; Sohrab Ghouzivand; Mohammad M Khodaei; Mehdi Ardalani

    2016-04-01

    5-[4-(dimethylamino)benzylidene) pyrimidine-2,4,6(1H,3H,5H)]-trione (DMP-3H), the receptor was synthesized which played a chemosensor role for cyanide ion (CN−) in aqueous solution with colorimetric and fluorescence turn-off responses. Upon addition of CN− ion into the solution containing the receptor, a color change visible to the naked eye was observed from yellow to colourless and also, the fluorescence of the solution was immediately quenched. Moreover, DMP-3H exhibited a selective response to cyanide ion over many other anions such as F−, Cl−, Br−, I−, SO$^{2−}_{3}$ , OCN−, ClO$^{−}_{3}$ , CO$^{2−}_{3}$ , IO$^{−}_{3}$ , N$^{−}_{3}$ , C$_{2}$O$^{2−}_{4}$ and SCN−. The detection limit toward CN− was 8.1 × 10−7 mol.L−1, which is satisfactory enough for monitoring CN− levels in physiological and environmental systems.

  15. Aqueous solutions of uranium(VI) as studied by time-resolved emission spectroscopy: a round-robin test.

    Science.gov (United States)

    Billard, Isabelle; Ansoborlo, Eric; Apperson, Kathleen; Arpigny, Sylvie; Azenha, M Emilia; Birch, David; Bros, Pascal; Burrows, Hugh D; Choppin, Gregory; Couston, Laurent; Dubois, Veronique; Fanghänel, Thomas; Geipel, Gerhard; Hubert, Solange; Kim, Jae I; Kimura, Takaumi; Klenze, Reinhardt; Kronenberg, Andreas; Kumke, Michael; Lagarde, Gerard; Lamarque, Gerard; Lis, Stefan; Madic, Charles; Meinrath, Gunther; Moulin, Christophe; Nagaishi, Ryuji; Parker, David; Plancque, Gabriel; Scherbaum, Franz; Simoni, Eric; Sinkov, Sergei; Viallesoubranne, Carole

    2003-08-01

    Results of an inter-laboratory round-robin study of the application of time-resolved emission spectroscopy (TRES) to the speciation of uranium(VI) in aqueous media are presented. The round-robin study involved 13 independent laboratories, using various instrumentation and data analysis methods. Samples were prepared based on appropriate speciation diagrams and, in general, were found to be chemically stable for at least six months. Four different types of aqueous uranyl solutions were studied: (1) acidic medium where UO2(2+)aq is the single emitting species, (2) uranyl in the presence of fluoride ions, (3) uranyl in the presence of sulfate ions, and (4) uranyl in aqueous solutions at different pH, promoting the formation of hydrolyzed species. Results between the laboratories are compared in terms of the number of decay components, luminescence lifetimes, and spectral band positions. The successes and limitations of TRES in uranyl analysis and speciation in aqueous solutions are discussed.

  16. Surface Modification of the LiFePO4 Cathode for the Aqueous Rechargeable Lithium Ion Battery.

    Science.gov (United States)

    Tron, Artur; Jo, Yong Nam; Oh, Si Hyoung; Park, Yeong Don; Mun, Junyoung

    2017-03-28

    The LiFePO4 surface is coated with AlF3 via a simple chemical precipitation for aqueous rechargeable lithium ion batteries (ARLBs). During electrochemical cycling, the unfavorable side reactions between LiFePO4 and the aqueous electrolyte (1 M Li2SO4 in water) leave a highly resistant passivation film, which causes a deterioration in the electrochemical performance. The coated LiFePO4 by 1 wt % AlF3 has a high discharge capacity of 132 mAh g(-1) and a highly improved cycle life, which shows 93% capacity retention even after 100 cycles, whereas the pristine LiFePO4 has a specific capacity of 123 mAh g(-1) and a poor capacity retention of 82%. The surface analysis results, which include X-ray photoelectron spectroscopy and transmission electron microscopy results, show that the AlF3 coating material is highly effective for reducing the detrimental surface passivation by relieving the electrochemical side reactions of the fragile aqueous electrolyte. The AlF3 coating material has good compatibility with the LiFePO4 cathode material, which mitigates the surface diffusion obstacles, reduces the charge-transfer resistances and improves the electrochemical performance and surface stability of the LiFePO4 material in aqueous electrolyte solutions.

  17. LHC BFPP Quench Test with Ions (2015)

    CERN Document Server

    Schaumann, Michaela; Bahamonde Castro, Cristina; Auchmann, Bernhard; Chetvertkova, Vera; Giachino, Rossano; Jowett, John; Kalliokoski, Matti; Lechner, Anton; Mertens, Tom; Ponce, Laurette; CERN. Geneva. ATS Department

    2016-01-01

    The 2015 Pb-Pb collision run of the LHC operated at a beam energy of 6.37Z TeV. The power of the secondary beams emitted from the interaction point by the bound-free pair production (BFPP) process reached new levels while the propensity of the bending magnets to quench is higher at the new magnetic field levels. This beam power is about 70 times greater than that contained in the luminosity debris and is focussed on a specific location. As long foreseen, orbit bumps were introduced in the dispersion suppressors around the highest luminosity experiments to mitigate the risk of quenches by displacing and spreading out these losses. Because the impact position and intensity of these secondary beams is well known and can be tracked easily with the Beam Loss Monitors (BLMs), the BFPP1 beam (208Pb81+ ions), which is the most intense, provides a tool to accurately measure the steady state quench limit of the LHC main dipoles. At the moment the exact quench limit is not known, but this knowledge is important to asses...

  18. Preparation and characterization of poly(ethyl hydrazide)-grafted oil palm empty fruit bunch fibre for the removal of Cu(II) ions from an aqueous environment.

    Science.gov (United States)

    Johari, Ili Syazana; Yusof, Nor Azah; Haron, Md Jelas; Nor, Siti Mariam Mohd

    2013-07-18

    Poly(ethyl hydrazide)-grafted oil palm empty fruit bunch fibre (peh-g-opefb) was successfully prepared by heating poly(methyl acrylate)-grafted opefb (pma-g-opefb) at 60 °C for 4 h with a solution of hydrazine hydrate (15% v/v) in ethanol. The Fourier transform infrared spectrum of the product shows a secondary amine peak at 3267 cm⁻¹, with amide carbonyl peaks at 1729 cm⁻¹ and 1643 cm⁻¹. The chelating ability of peh-g-opefb was tested with copper ion in aqueous solution. A batch adsorption study revealed that maximum adsorption of copper ion was achieved at pH 5. An isotherm study showed the adsorption follows a Langmuir model, with a maximum adsorption capacity of 43.48 mg g-1 at 25 °C. A kinetic study showed that the adsorption of copper ion rapidly reaches equilibrium and follows a pseudo-second-order kinetic model, with a constant rate of 7.02 × 10⁻⁴ g mg⁻¹ min⁻¹ at 25 °C. The Gibbs free energy, ∆G⁰, value is negative, indicating a spontaneous sorption process. Entropy, ∆S⁰, gives a positive value, indicating that the system is becoming increasingly disordered after the adsorption of copper ion. A positive enthalpy value, ∆H⁰, shows that the endothermic process takes place during the adsorption and is more favourable at high temperatures.

  19. Preparation and Characterization of Poly(ethyl hydrazide-Grafted Oil Palm Empty Fruit Bunch Fibre for the Removal of Cu(II Ions from an Aqueous Environment

    Directory of Open Access Journals (Sweden)

    Siti Mariam Mohd Nor

    2013-07-01

    Full Text Available Poly(ethyl hydrazide-grafted oil palm empty fruit bunch fibre (peh-g-opefb was successfully prepared by heating poly(methyl acrylate-grafted opefb (pma-g-opefb at 60 °C for 4 h with a solution of hydrazine hydrate (15% v/v in ethanol. The Fourier transform infrared spectrum of the product shows a secondary amine peak at 3267 cm−1, with amide carbonyl peaks at 1729 cm−1 and 1643 cm−1. The chelating ability of peh-g-opefb was tested with copper ion in aqueous solution. A batch adsorption study revealed that maximum adsorption of copper ion was achieved at pH 5. An isotherm study showed the adsorption follows a Langmuir model, with a maximum adsorption capacity of 43.48 mg g−1 at 25 °C. A kinetic study showed that the adsorption of copper ion rapidly reaches equilibrium and follows a pseudo–second-order kinetic model, with a constant rate of 7.02 × 10−4 g mg−1 min−1 at 25 °C. The Gibbs free energy, ∆G⁰, value is negative, indicating a spontaneous sorption process. Entropy, ∆S⁰, gives a positive value, indicating that the system is becoming increasingly disordered after the adsorption of copper ion. A positive enthalpy value, ∆H⁰, shows that the endothermic process takes place during the adsorption and is more favourable at high temperatures.

  20. Cytotoxicity of aqueous extracts of Rosmarinus officinalis L. (Labiatae in plant test system

    Directory of Open Access Journals (Sweden)

    GHS Cardoso

    Full Text Available This study investigated the cytotoxic activity of Rosmarinus officinalis L. (rosemary aqueous extract on the cell cycle of Allium cepa. To this end, crude aqueous leaf extracts at four concentrations, 0.02, 0.04, 0.06 and 0.08 mg/mL, were tested on A. cepa meristematic root cells, at exposure times of 24 and 48h. Slides were prepared by the crushing technique, and cells analyzed throughout the cell cycle, totaling 5,000 for each control group and concentration. The four concentrations tested, including the lowest and considered ideal for use, at all exposure times, showed a significant antiproliferative effect on the cell cycle of this test system and presented a high number of cells in prophase. Our results evidenced the cytotoxicity of rosemary extracts, under the studied conditions.

  1. Cytotoxicity of aqueous extracts of Rosmarinus officinalis L. (Labiatae) in plant test system.

    Science.gov (United States)

    Cardoso, G H S; Dantas, E B S; Sousa, F R C; Peron, A P

    2014-11-01

    This study investigated the cytotoxic activity of Rosmarinus officinalis L. (rosemary) aqueous extract on the cell cycle of Allium cepa. To this end, crude aqueous leaf extracts at four concentrations, 0.02, 0.04, 0.06 and 0.08 mg/mL, were tested on A. cepa meristematic root cells, at exposure times of 24 and 48 h. Slides were prepared by the crushing technique, and cells analyzed throughout the cell cycle, totaling 5,000 for each control group and concentration. The four concentrations tested, including the lowest and considered ideal for use, at all exposure times, showed a significant antiproliferative effect on the cell cycle of this test system and presented a high number of cells in prophase. Our results evidenced the cytotoxicity of rosemary extracts, under the studied conditions.

  2. Recovery of metals from simulant spent lithium-ion battery as organophosphonate coordination polymers in aqueous media.

    Science.gov (United States)

    Perez, Emilie; Andre, Marie-Laure; Navarro Amador, Ricardo; Hyvrard, François; Borrini, Julien; Carboni, Michaël; Meyer, Daniel

    2016-11-01

    An innovative approach is proposed for the recycling of metals from a simulant lithium-ion battery (LIBs) waste aqueous solution. Phosphonate organic linkers are introduced as precipitating agents to selectively react with the metals to form coordination polymers from an aqueous solution containing Ni, Mn and Co in a hydrothermal process. The supernatant is analyzed by ICP-AES to quantify the efficiency and the selectivity of the precipitation and the materials are characterized by Scanning Electron Microscopy (SEM), Powder X-Ray Diffraction (PXRD), Thermogravimetric Analyses (TGA) and nitrogen gas sorption (BET). Conditions have been achieved to selectively precipitate Manganese or Manganese/Cobalt from this solution with a high efficiency. This work describes a novel method to obtain potentially valuable coordination polymers from a waste metal solution that can be generalized on any waste solution.

  3. Nano-cerium vanadate: a novel inorganic ion exchanger for removal of americium and uranium from simulated aqueous nuclear waste.

    Science.gov (United States)

    Banerjee, Chayan; Dudwadkar, Nilesh; Tripathi, Subhash Chandra; Gandhi, Pritam Maniklal; Grover, Vinita; Kaushik, Chetan Prakash; Tyagi, Avesh Kumar

    2014-09-15

    Cerium vanadate nanopowders were synthesized by a facile low temperature co-precipitation method. The product was characterized by X-ray diffraction and transmission electron microscopy and found to consist of ∼25 nm spherical nanoparticles. The efficiency of these nanopowders for uptake of alpha-emitting radionuclides (233)U (4.82 MeV α) and (241)Am (5.49 MeV α, 60 keV γ) has been investigated. Thermodynamically and kinetically favorable uptake of these radionuclides resulted in their complete removal within 3h from aqueous acidic feed solutions. The uptake capacity was observed to increase with increase in pH as the zeta potential value decreased with the increase in pH but effect of ionic strength was insignificant. Little influence of the ions like Sr(2+), Ru(3+), Fe(3+), etc., in the uptake process indicated CeVO4 nanopowders to be amenable for practical applications. The isotherms indicated predominant uptake of the radioactive metal ions in the solid phase of the exchanger at lower feed concentrations and linear Kielland plots with positive slopes indicated favorable exchange of the metal ions with the nanopowder. Performance comparison with the other sorbents reported indicated excellent potential of nano-cerium vanadate for removing americium and uranium from large volumes of aqueous acidic solutions.

  4. Speciation of phytate ion in aqueous solution. Cadmium(II) interactions in aqueous NaCl at different ionic strengths

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, Concetta de; Milea, Demetrio; Porcino, Nunziatina; Sammartano, Silvio [Universita di Messina, Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Messina (Italy)

    2006-09-15

    Interactions between myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate) (phytic acid) and cadmium(II) were studied by using potentiometry (at 25 C with the ISE-H{sup +} glass electrode) in different metal to ligand (Phy) ratios (1:1{<=}Cd{sup 2+}:Phy{<=}4:1) in NaCl{sub aq} at different ionic strengths (0.1{<=}I/mol L{sup -1}{<=}1). Nine Cd{sub i}H{sub j}Phy{sup (12-2i-j)-} species are formed with i=1 and 2 and 4{<=}j{<=}7; and trinuclear Cd{sub 3}H{sub 4}Phy{sup 2-}. Dependence of complex formation constants on ionic strength was modeled by using Specific ion Interaction Theory (SIT) equations. Phytate and cadmium speciation are also dependent on the metal to ligand ratio. Stability of Cd{sub i}H{sub j}Phy{sup (12-2i-j)-} species was modeled as a function of both the ligand protonation step (j) and the number of metal cations bound to phytate (i), and relationships found were used for the prediction of species other than those experimentally determined (mainly di- and tri-protonated complexes), allowing the possibility of modeling Phy and Cd(II) behavior in natural waters and biological fluids. A critical evaluation of phytate sequestering ability toward cadmium(II) has been made under several experimental conditions, and the determination of an empirical parameter has been proposed for an objective ''quantification'' of this ability. A thorough analysis of literature data on phytate-cadmium(II) complexes has been performed. (orig.)

  5. Nano-cerium vanadate: A novel inorganic ion exchanger for removal of americium and uranium from simulated aqueous nuclear waste

    Energy Technology Data Exchange (ETDEWEB)

    Banerjee, Chayan; Dudwadkar, Nilesh [Fuel Reprocessing Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tripathi, Subhash Chandra, E-mail: sctri001@gmail.com [Fuel Reprocessing Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Gandhi, Pritam Maniklal [Fuel Reprocessing Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Grover, Vinita [Waste Management Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kaushik, Chetan Prakash [Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Tyagi, Avesh Kumar, E-mail: aktyagi@barc.gov.in [Waste Management Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-09-15

    Highlights: • Template free, low temperature synthesis of CeVO{sub 4} nanopowders. • Thermodynamically and kinetically favourable uptake of Am(III) and U(VI) exhibited. • K{sub d} and ΔG° values for Am(III) and U(VI) uptake in pH 1–6 are reported. • Interdiffusion coefficients and zeta potential values in pH 1–6 are reported. • Possible application in low level aqueous nuclear waste remediation. - Abstract: Cerium vanadate nanopowders were synthesized by a facile low temperature co-precipitation method. The product was characterized by X-ray diffraction and transmission electron microscopy and found to consist of ∼25 nm spherical nanoparticles. The efficiency of these nanopowders for uptake of alpha-emitting radionuclides {sup 233}U (4.82 MeV α) and {sup 241}Am (5.49 MeV α, 60 keV γ) has been investigated. Thermodynamically and kinetically favorable uptake of these radionuclides resulted in their complete removal within 3 h from aqueous acidic feed solutions. The uptake capacity was observed to increase with increase in pH as the zeta potential value decreased with the increase in pH but effect of ionic strength was insignificant. Little influence of the ions like Sr{sup 2+}, Ru{sup 3+}, Fe{sup 3+}, etc., in the uptake process indicated CeVO{sub 4} nanopowders to be amenable for practical applications. The isotherms indicated predominant uptake of the radioactive metal ions in the solid phase of the exchanger at lower feed concentrations and linear Kielland plots with positive slopes indicated favorable exchange of the metal ions with the nanopowder. Performance comparison with the other sorbents reported indicated excellent potential of nano-cerium vanadate for removing americium and uranium from large volumes of aqueous acidic solutions.

  6. 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.

  7. Influence of activated carbon surface acidity on adsorption of heavy metal ions and aromatics from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Sanae; Yoshihara, Kazuya; Moriyama, Koji [Faculty of Engineering, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522 (Japan); Machida, Motoi [Graduate School of Engineering, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522 (Japan)], E-mail: machida@faculty.chiba-u.jp; Tatsumoto, Hideki [Graduate School of Engineering, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522 (Japan)

    2007-08-15

    Adsorption of toxic heavy metal ions and aromatic compounds onto activated carbons of various amount of surface C-O complexes were examined to study the optimum surface conditions for adsorption in aqueous phase. Cadmium(II) and zinc(II) were used as heavy metal ions, and phenol and nitrobenzene as aromatic compounds, respectively. Activated carbon was de-ashed followed by oxidation with nitric acid, and then it was stepwise out-gassed in helium flow up to 1273 K to gradually remove C-O complexes introduced by the oxidation. The oxidized activated carbon exhibited superior adsorption for heavy metal ions but poor performance for aromatic compounds. Both heavy metal ions and aromatics can be removed to much extent by the out-gassed activated carbon at 1273 K. Removing C-O complexes, the adsorption mechanisms would be switched from ion exchange to C{pi}-cation interaction for the heavy metals adsorption, and from some kind of oxygen-aromatics interaction to {pi}-{pi} dispersion for the aromatics.

  8. A Novel Experimental Technique to Monitor the Time-Dependent Water and Ions Uptake when Shale Interacts with Aqueous Solutions

    Science.gov (United States)

    AL-Bazali, Talal

    2013-09-01

    The time-dependent water and ions uptake when shale interacts with aqueous solutions is quantified using a combination of immersion and gravimetric techniques. Results show that when shale interacts with salt solutions, water uptake into shale goes through three distinct stages; water movement out of shale (due to chemical osmosis), water movement into shale (due to diffusion osmosis) and stationary state (equilibrium stage). This work shows that chemical osmosis dominates water movement in early times while diffusion osmosis takes over later. In addition, it is shown that the amount of water movement due to chemical osmosis depends on the chemical potential gradient while the amount of water movement due to diffusion osmosis is highly related to the ionic concentration imbalance. In addition, the amount of ions uptake into shale at equilibrium is shown to depend on the type and concentration of salt solution. Furthermore, this work shows that potassium ion has a strengthening effect on shale while sodium and calcium ions have a weakening effect on shale. Results also show that the shale's compressive strength alteration is greatly influenced by the type and concentration of the salt solution. Furthermore, the shale's compressive strength alteration is shown to be time dependent and correlates very well with the time-dependent flux of water and ions. Finally, it is shown that chemical osmosis and diffusion osmosis take place simultaneously when shale interacts with water-based muds. The overall impact on shale stability is governed by the net water flow resulting from chemical osmosis and diffusion osmosis.

  9. Effect of ion charges on the electric double layer capacitance of activated carbon in aqueous electrolyte systems

    Science.gov (United States)

    Icaza, Juan C.; Guduru, Ramesh K.

    2016-12-01

    Carbon based electrochemical double layer capacitors (EDLCs) are known for high power density, but their energy density is limited due to surface characteristics of the electrode materials as well as the size and charge of the ions used in the electrolyte. Therefore, considering the current demand for enhanced energy density devices, we investigated the use of multivalent electrolytes to increase the capacitance of activated carbon (AC) based EDLCs. As part of these studies, we examined the effect of the charge of the multivalent ions on the capacitive behavior of microporous AC electrodes and compared with the univalent Li+ system. We performed impedance and cyclic voltammetry measurements on AC electrodes in a symmetric two electrode configuration to determine the impedance and capacitance with respect to varying charge and concentration of the ions in the aqueous nitrate electrolytes. These studies clearly demonstrated an increased capacitance with Mg2+ and Al3+ implying the possible effects of ion mobility and electrolyte conductivity in addition to the multivalent charge. These preliminary observations clearly point to the importance of selection of electrolyte ions with more charge, conductivity, and suitable size with respect to the pore size of the electrodes in order to increase the capacitance of EDLCs.

  10. CYCLIC VOLTAMMETRY STUDIES OF COPPER (II AND TELLURIUM (IV IONS IN ACIDIC AQUEOUS SOLUTIONS FOR THIN FILM DEPOSITION

    Directory of Open Access Journals (Sweden)

    SARAVANAN NAGALINGAM

    2014-05-01

    Full Text Available Cyclic voltammetry studies of copper (II and tellurium (IV ions in acidic aqueous solutions were carried out to determine the optimum condition for copper telluride thin film deposition. The voltammetry studies include reversible scans at different solution pH. Based on the voltammogram, suitable deposition conditions was determined to be in the range of -0.35 V to -0.45 V versus Ag/AgCl at pH values between 2.0 to 2.2 under non diffusion-limited conditions.

  11. Lithium Ion Testing at NSWC Crane in Support of NASA Goddard Space Flight Center

    Science.gov (United States)

    Brown, Harry; Jung, David; Lee, Leonine

    2010-01-01

    This viewgraph presentation reviews Lithium Ion Cell testing at the Naval Surface Warfare Center in Crane, India. The contents include: 1) Quallion 15 Ahr Lithium-Ion Cells, LEO Life Cycle Test; 2) Lithion 50 Ahr Lithium-Ion Cells, LEO Life Cycle Test; 3) ABSL 5 Ahr Lithium-Ion Battery, LRO-LLO Life Cycle Test, SDO-GEO Life Cycle Test; and 4) A123 40 Ahr Lithium-Ion Battery, GPM Life Cycle Test, MMS Life Cycle Test.

  12. A polyamide receptor based benzothiazole derivative: highly selective and sensitive fluorescent sensor for Hg{sup 2+} ion in aqueous medium

    Energy Technology Data Exchange (ETDEWEB)

    Maity, Shubhra Bikash; Bharadwaj, Parimal K., E-mail: pkb@iitk.ac.in

    2015-05-15

    A water soluble benzothiazole derivative having polyamide arms has been designed and synthesized. The sensor selectively detects Hg{sup 2+} ion in aqueous medium in presence of alkali, alkaline earth, first row transition metal and heavy metal ions. The reversible behaviour of the sensor can be achieved in presence of iodide ion. - Highlights: • A benzothiazole derivative having polyamide arms has been designed and synthesized. • It selectively detects Hg{sup 2+} ion in presence of host of monovalent, divalent and trivalent ions in aqueous medium. • It works through a reversible way. • The detection limit for Hg{sup 2+} ion was found to be 7.15×10{sup −7} M.

  13. lithium-ion battery during oven tests

    Science.gov (United States)

    Peng, Peng; Sun, Yiqiong; Jiang, Fangming

    2014-10-01

    A three dimensional thermal abuse model for graphite/LiPF6/LiCoO2 batteries is established particularly for oven tests. To investigate the influence of heat release condition and oven temperature on battery thermal behaviors, we perform a series of simulations with respect to a unit cell during oven thermal abuses of various oven temperatures and under various heat release conditions. Simulation results enable detailed analyses to thermal behaviors of batteries. It is found that during oven thermal abuse processes that do not get into thermal runaway, the negative electrode is the maximum heat generation rate zone; during oven thermal abuse processes that do get into thermal runaway, the positive electrode is the maximum heat generation rate zone. The positive-solvent reaction is found to be the major heat generation source causing thermal runaway. It is also found that the heat release condition and the oven temperature are combined to dictate thermal behaviors of the battery. The critical oven temperature that causes thermal runaway rises if the heat release condition is better and the critical heat release coefficient that can effectively restrain the occurrence of thermal runaway increases with the increase of oven temperature.

  14. Fundamental tests of nature with cooled and stored exotic ions

    CERN Document Server

    CERN. Geneva

    2014-01-01

    The presentation will concentrate on recent applications with exciting results of Penning traps in atomic and nuclear physics with cooled and stored exotic ions. These are high-accuracy mass measurements of short-lived radionuclides, g-factor determinations of the bound-electron in highly-charged, hydrogen-like ions and g-factor measurements of the proton and antiproton. The experiments are dedicated, e.g., to astrophysics studies and to tests of fundamental symmetries in the case of mass measurements on radionuclides, and to the determination of fundamental constants and a CPT test in the case of the g-factor measurements.

  15. Kinetics and Mechanism of the Oxidation of Naphthol Green B by Peroxydisulphate Ion in Aqueous Acidic Medium

    Directory of Open Access Journals (Sweden)

    B. Myek

    2014-01-01

    Full Text Available The kinetics of the oxidation of naphthol green B (NGB3− by peroxydisulphate ion has been carried out in aqueous acidic medium at λmax of 700 nm, T=23±1°C, and I=0.50 mol dm−3 (NaCl. The reaction shows a first-order dependence on oxidant and reductant concentration, respectively. The stoichiometry of the NGB—S2O82- reaction is 1 : 2. Change in hydrogen ions concentration of the reaction medium has no effect on the rate of the reaction. Added cations and anions decreased the rate of the reaction. The results of spectroscopic and kinetic investigation indicate that no intermediate complex is probably formed in the course of this reaction.

  16. Investigation on the extraction of strontium ions from aqueous phase using crown ether-ionic liquid systems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The extraction of strontium ions using DCH18C6 as the extractant and various ionic liquids(ILs) as solvents has been investigated.The distribution ratio of Sr2+ can reach as high as 103 under certain conditions,much larger than that in DCH18C6/n-octanol system.The extraction capacity depends greatly on the structure of ionic liquids.In Ils-based extraction systems,the extraction efficiency of strontium ions is reduced by increasing the concentration of nitric acid and can also be influenced directly by the presence of Na+ and K+ in the aqueous phase.It is confirmed that the extraction proceeds mainly via a cation-exchange mechanism.

  17. Investigation on the extraction of strontium ions from aqueous phase using crown ether-ionic liquid systems

    Institute of Scientific and Technical Information of China (English)

    XU Chao; SHEN XingHai; CHEN QingDe; GAO HongCheng

    2009-01-01

    The extraction of strontium ions using DCH18C6 as the extractant and various ionic liquids (Ils) as solvents has been investigated.The distribution ratio of Sr~(2+) can reach as high as 10~3 under certain conditions,much larger than that in DCH18C6/n-octanol system.The extraction capacity depends greatly on the structure of ionic liquids.In Ils-based extraction systems,the extraction efficiency of strontium ions is reduced by increasing the concentration of nitric acid and can also be influenced directly by the presence of Na~+ and K~+ in the aqueous phase.It is confirmed that the extraction proceeds mainly via a cation-exchange mechanism.

  18. A Post-Synthetically Modified MOF for Selective and Sensitive Aqueous-Phase Detection of Highly Toxic Cyanide Ions.

    Science.gov (United States)

    Karmakar, Avishek; Kumar, Naveen; Samanta, Partha; Desai, Aamod V; Ghosh, Sujit K

    2016-01-18

    Selective and sensitive detection of toxic cyanide (CN(-) ) by a post-synthetically altered metal-organic framework (MOF) has been achieved. A post-synthetic modification was employed in the MOF to incorporate the specific recognition site with the CN(-) ion over all other anions, such as Cl(-) , Br(-) , and SCN(-) . The aqueous-phase sensing and very low detection limit, the essential prerequisites for an effective sensory material, have been fulfilled by the MOF. Moreover, the present detection level meets the standard set by the World Health Organization (WHO) for the permissible limit of cyanide concentration in drinking water. The utilization of MOF-based materials as the fluorometric probes for selective and sensitive detection of CN(-) ions has not been explored till now.

  19. Capacitance of graphene in aqueous electrolytes: The effects of dielectric saturation of water and finite size of ions

    Science.gov (United States)

    Sharma, P.; Mišković, Z. L.

    2014-09-01

    We present a theoretical model for electrolytically top-gated graphene, in which we analyze the effects of dielectric saturation of water due to possibly strong electric fields near the surface of a highly charged graphene, as well as the steric effects due to the finite size of salt ions in an aqueous electrolyte. By combining two well-established analytical models for those two effects, we show that the total capacitance of the solution-gated graphene is dominated by its quantum capacitance for gating potentials ≲1V, which is the range of primary interest for most sensor applications of graphene. On the other hand, at the potentials ≳1V the total capacitance is dominated by a universal capacitance of the electric double layer in the electrolyte, which exhibits a dramatic decrease of capacitance with increasing gating potential due to the interplay of a fully saturated dielectric constant of water and ion crowding near graphene.

  20. Removal of copper (II) from aqueous solutions by flotation using polyaluminum chloride silicate (PAX-XL60 S) as coagulant and carbonate ion as activator.

    Science.gov (United States)

    Ghazy, S E; Mahmoud, I A; Ragab, A H

    2006-01-01

    Flotation is a separation technology for removing toxic heavy metal ions from aqueous solutions. Here a simple and rapid flotation procedure is presented for the removal of copper(II) from aqueous solutions. It is based on the use of polyaluminum chloride silicate (PAX-XL60 S) as coagulant and flocculent, carbonate ion as activator and oleic acid (HOL) as surfactant. Both ion and precipitate flotation are included depending on the solution pH. Ion and precipitate flotation in the aqueous HOL-PAX-XL60 S-Cu2+-CO3(2-) system gave powerful preferential removal of Cu2+ (F -100%) over the HOL-PAX-XL60 S-Cu2+ system containing no CO3(2+) ion (F approximately 86%). The role of CO3(2-) ion is also evident from decreasing the dose of PAX-XL60 S from 700 mg l(-1) to 200 mg l(-1). The other parameters, influencing the flotation process, namely: metal ion, surfactant and PAX-XL60 S concentrations, ionic strength, temperature and foreign ions were examined. Moreover, the procedure was successfully applied to recover Cu2+ ions from different volumes up to 11 and from natural water samples.

  1. Role of aqueous sulfide and sulfate-reducing bacteria in the kinetics and mechanisms of the reduction of uranyl ion

    Energy Technology Data Exchange (ETDEWEB)

    Mohagheghi, A.

    1985-01-01

    Formation of sedimentary rock-hosted uranium ore deposits is thought to have resulted from the reduction by aqueous sulfide species of relatively soluble uranyl ion (U(VI)) to insoluble uranium(IV) oxides and silicates. The origin of this H/sub 2/S in such deposits can be either biogenic or abiogenic. Therefore, the kinetics and mechanism of uranyl ion reduction by aqueous sulfide, and the effect of several key variables on the reduction process in non-bacterial (sterile) systems was studied. The role of both pure and mixed cultures of sulfate-reducing bacteria on the reduction process was also investigated. In sterile systems the reduction reaction generally occurred by a two step reaction sequence. Uranium(V) (as UO/sub 2//sup +/) and U(IV) (as UO/sub 2/ the mineral uraninite) were the intermediate and final products, respectively. The initial concentration of uranyl ion required for reaction initiation had a minimum value of 0.8 ppm at pH 7, and was higher at pH values less than or greater than 7. An induction period was observed in all experiments. No reduction was observed after 8 hours at pH 8. Although increasing ionic strength increased the length of the induction period, it also increased the rate of the reduction of UO/sub 2//sup +/ in the second step. No reaction was observed under any experimental conditions with initial UO/sub 2//sup 2 +/ concentration less than 0.1 ppm, which is thought to be typical for ore forming solutions. However, by absorbing uranyl ion onto kaolinite, the reduction by H/sub 2/S occurred at lower UO/sub 2//sup 2 +/ concentrations (approx. 0.1 ppm) in that in the homogeneous system. Thus, adsorption may play a significant role in the reduction and therefore in the formation of ore deposits.

  2. Removal of thorium (IV) ions from aqueous solution by a novel nanoporous ZnO: Isotherms, kinetic and thermodynamic studies.

    Science.gov (United States)

    Kaynar, Ümit H; Ayvacıklı, Mehmet; Hiçsönmez, Ümran; Kaynar, Sermin Çam

    2015-12-01

    The adsorption of thorium (IV) from aqueous solutions onto a novel nanoporous ZnO particles prepared by microwave assisted combustion was studied using batch methods under different experimental conditions. The effect of contact time, solution pH, initial concentration and temperature on adsorption process was studied. The ability of this material to remove Th (IV) from aqueous solution was characterises by Langmuir, Freunlinch and Temkin adsorption isotherms. The adsorption percent and distribution coefficient for nanoporous ZnO powders in optimum conditions were 97% ± 1.02; 8080 L kg(-1)for Th (IV), respectively. Based on the Langmuir model, the maximum adsorption capacity of nanoporous ZnO for Th (IV) was found to be 1500 g kg(-1). Thermodynamic parameters were determined and discussed. The results indicated that nanoporous ZnO was suitable as sorbent material for recovery and adsorption of Th (IV) ions from aqueous solutions. The radioactive Th (VI) in surface water, sea water and waste waters from technologies producing nuclear fuels, mining (uranium and thorium) and laboratories working with radioactive materials (uranium and thorium) can be removed with this nanoporous ZnO.

  3. Synthesis and crystal structure of imidazole containing amide as a turn on fluorescent probe for nickel ion in aqueous media. An experimental and theoretical investigation

    Science.gov (United States)

    Annaraj, B.; Mitu, L.; Neelakantan, M. A.

    2016-01-01

    Imidazole containing amide fluorescence probe (PAIC) for Ni2+ was designed and successfully synthesized in good yield by reaction between 1-methyl-1H-imidazole-2-carboxylic acid and L-phenylalanine methyl ester. The probe was characterized by FTIR, 1H NMR, ESI-MS, UV-vis and fluorescence spectroscopy. Single crystal XRD analysis reveals that PAIC crystallizes in a monoclinic crystal lattice system with the space group of P21/n. Chemosensor property of PAIC was tested against different metal ions by UV-vis and fluorescent techniques in aqueous medium. Test results show that PAIC has high selectivity for Ni2+ compared to other metal ions (Na+, K+, Ca2+, Ag+, Co2+, Cu2+, Fe2+, Fe3+, Hg2+, Mn2+, Zn2+ and Pb2+). Time-dependent density functional theory (TD-DFT) and configuration interaction singles (CIS) calculations were carried out to understand the sensing mechanism. The practical applicability of PAIC was tested in real water samples.

  4. Removal of sodium and chloride ions from aqueous solutions using fique fibers (Furcraea spp.).

    Science.gov (United States)

    Agudelo, Nikolay; Hinestroza, Juan P; Husserl, Johana

    2016-01-01

    Fique fibers obtained from the leaves of Furcraea spp., a highly abundant plant in the mountains of South America, may offer an alternative as biosorbents in desalination processes as they exhibit high removal capacities (13.26 meq/g for chloride ions and 15.52 meq/g for sodium ions) up to four times higher than exchange capacities commonly observed in synthetic resins. The ion removal capacity of the fibers was also found to be a function of the pH of the solution with the maximum removal of ions obtained at pH 8. Unlike most commercial ion exchange resins, our results suggest that fique fibers allow simultaneous removal of chloride and sodium ions.

  5. Removal of Cr(VI) and As(V) ions from aqueous solutions by polyacrylate and polystyrene anion exchange resins

    Science.gov (United States)

    Jachuła, Justyna; Hubicki, Zbigniew

    2013-09-01

    The sorption of Cr(VI) and As(V) from the aqueous solutions with the polyacrylate anion exchangers of the strong base functional groups Amberlite IRA 458 and Amberlite IRA 958 was studied. The studies were carried out by the static-batch method. The concentration of Cr(VI) and As(V) ions in the aqueous solution was determined by the UV-VIS spectrophotometer. The influence of several parameters was studied with respect to sorption equilibrium. The phase contact time and the concentration affect the sorption process. The equilibrium state was established already after 15 min of phase contact time. Maximum uptake of Cr(VI) and As(V) occurred at pH 5 and 10, respectively. The determined kinetic parameters imply that the sorption process proceeds according to the equation type of pseudo second-order. Sorption equilibrium data were correlated with the Langmuir and Freundlich isotherms. Removal of As(V) ions on macroporous Amberlite IRA 900 decreased about 12 % in presence of other anions (Cl-, NO3 -, SO4 2-) in the solution. The sorption was temperature dependent.

  6. The use of exhausted olive cake ash (EOCA) as a low cost adsorbent for the removal of toxic metal ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Z. Elouear; J. Bouzid; N. Boujelben; M. Feki; A. Montiel [Ecole Nationale d' Ingenieurs de Sfax, Sfax (Tunisia). Laboratoire Eau Energie et Environnement

    2008-09-15

    The removal characteristics of cadmium (Cd(II)) and nickel (Ni(II)) ions from aqueous solution by exhausted olive cake ash (EOCA) were investigated under various conditions of contact time, pH, initial metal concentration and temperature. Batch kinetic studies showed that an equilibrium time of 2 h was required for the adsorption of Ni(II) and Cd(II) onto EOCA. Equilibrium adsorption is affected by the initial pH (pH{sub 0}) of the solution. The pH{sub 0} 6.0 is found to be the optimum for the individual removal of Cd(II) and Ni(II) ions by EOCA. The adsorption test of applying EOCA into synthetic wastewater revealed that the adsorption data of this material for nickel and cadmium ions were better fitted to the Langmuir isotherm since the correlation coefficients for the Langmuir isotherm were higher than that for the Freundlich isotherm. The estimated maximum capacities of nickel and cadmium ions adsorbed by EOCA were 8.38 and 7.32 mg g{sup -1}, respectively. The thermodynamic parameters for the adsorption process data were evaluated using Langmuir isotherm. The free energy change ({Delta}G{sup 0}) and the enthalpy change ({Delta}H{sup 0}) showed that the process was feasible and endothermic respectively. As the exhausted olive cake is discarded as waste from olive processing, the adsorbent derived from this material is expected to be an economical product for metal ion remediation from water and wastewater. 45 refs., 7 figs., 4 tabs.

  7. Interaction between Langmuir and Langmuir-Blodgett films of two calix[4]arenes with aqueous copper and lithium ions.

    Science.gov (United States)

    Supian, Faridah L; Richardson, Tim H; Deasy, Mary; Kelleher, Fintan; Ward, James P; McKee, Vickie

    2010-07-06

    The binding interactions between aqueous copper (Cu(2+)) and lithium (Li(+)) ions and Langmuir monolayers and Langmuir-Blodgett (LB) multilayers have been investigated by studying surface pressure-area (Pi-A) isotherms and surface potential-area (DeltaV-A) behavior in order to find the effective dipole moment, mu(perpendicular), of the calixarene molecules in the uncomplexed and complexed states. The orientation of both calix[4]arenes, namely, 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene and 5,17-(9H-fluoren-2-yl)methyleneamino)-11,23-di-tert-butyl-25,27-diethoxycarbonyl methyleneoxy-26,28-dihydroxycalix[4]arene, is such that the plane of the calix ring is parallel with the plane of the water surface regardless of the ion content of the subphase. The Gibbs equation was used to interpret the adsorption of ions with both calix[4]arenes as a function of the concentration. Effective dipole moments have been calculated from surface potential values using the Helmholtz equation. In this work, new LB films have been prepared employing two novel amphiphilic calix[4]arene derivatives bearing different upper rim substituents. Thus, the effect of modifiying the upper rim has been observed. The results have shown that these calixarenes may be useful components of ion sensors.

  8. Role of Citrate Ions in the Phosphonate-based Inhibitor System for Mild Steel in Aqueous Chloride Media

    Directory of Open Access Journals (Sweden)

    G. Gunasekaran

    2005-01-01

    Full Text Available The corrosion inhibition efficiency of phosphonic acid and its derivatives for the inhibition of corrosion of mild steel in neutral chloride media is decided by its ability to form protectivefilm over the surface. In this context, the effect of addition of metal cations and certain organic compounds, such as citrate in conjugation with phosphonic acid to impart synergistic corrosion inhibition has been explored. The experiments were carried out using various concentrations of trisodium citrate and zinc ions in an aqueous solution of 2-carboxyethyl phosphonic acid (2CEPA at 25 ppm. The corrosion characteristics have been determined using electrochemical impedance spectroscopy together with determination of corrosion rate by weight-loss method. It has been observed that a combination of inhibitive ions, namely citrate, ZCEPA, and zinc ions at 25 ppm gives 96 per cent inhibition efficiency and this corrosion inhibition is due to the formation of a protective film. By increasing the concentration of citrate beyond 25 ppm, the corrosion inhibition efficiency decreases. This paper discusses the role of citrate and zinc ions in imparting added corrosion inhibition ability using 2CEPA on the basis of experimental results.

  9. Performance and cost characteristics of multi-electron transfer, common ion exchange non-aqueous redox flow batteries

    Science.gov (United States)

    Laramie, Sydney M.; Milshtein, Jarrod D.; Breault, Tanya M.; Brushett, Fikile R.; Thompson, Levi T.

    2016-09-01

    Non-aqueous redox flow batteries (NAqRFBs) have recently received considerable attention as promising high energy density, low cost grid-level energy storage technologies. Despite these attractive features, NAqRFBs are still at an early stage of development and innovative design techniques are necessary to improve performance and decrease costs. In this work, we investigate multi-electron transfer, common ion exchange NAqRFBs. Common ion systems decrease the supporting electrolyte requirement, which subsequently improves active material solubility and decreases electrolyte cost. Voltammetric and electrolytic techniques are used to study the electrochemical performance and chemical compatibility of model redox active materials, iron (II) tris(2,2‧-bipyridine) tetrafluoroborate (Fe(bpy)3(BF4)2) and ferrocenylmethyl dimethyl ethyl ammonium tetrafluoroborate (Fc1N112-BF4). These results help disentangle complex cycling behavior observed in flow cell experiments. Further, a simple techno-economic model demonstrates the cost benefits of employing common ion exchange NAqRFBs, afforded by decreasing the salt and solvent contributions to total chemical cost. This study highlights two new concepts, common ion exchange and multi-electron transfer, for NAqRFBs through a demonstration flow cell employing model active species. In addition, the compatibility analysis developed for asymmetric chemistries can apply to other promising species, including organics, metal coordination complexes (MCCs) and mixed MCC/organic systems, enabling the design of low cost NAqRFBs.

  10. Highly effective adsorption of heavy metal ions from aqueous solutions by macroporous xylan-rich hemicelluloses-based hydrogel.

    Science.gov (United States)

    Peng, Xin-Wen; Zhong, Lin-Xin; Ren, Jun-Li; Sun, Run-Cang

    2012-04-18

    Xylan-rich hemicelluloses-based hydrogel was developed as a novel porous bioadsorbent by graft co-polymerization of acrylic acid (AA) and xylan-rich hemicelluloses for adsorption of heavy metal ions (Pd(2+), Cd(2+), and Zn(2+)) from aqueous solutions. The chemical structure, the interaction between the hydrogel and metal ions, and the porous structure of xylan-rich hemicelluloses-g-AA hydrogel were revealed by Fourier transform infrared spectroscopy and scanning electron microscopy. The effects of AA and cross-linker dosage, pH value, contacting time, and initial concentration of metal ion on the adsorption capacity were studied. The adsorption equilibrium time was about 60 min from the adsorption kinetics study. The maximum adsorption capacities of Pd(2+), Cd(2+), and Zn(2+) were 859, 495, and 274 mg/g, respectively. Furthermore, xylan-rich hemicelluloses-g-AA hydrogel also exhibited highly efficient regeneration and metal ion recovery efficiency and can be reused without noticeable loss of adsorption capacity for Pd(2+), Cd(2+), and Zn(2+) after quite a number of repeated adsorption/desorption cycles.

  11. Spectroscopic study of Mg(II) ion influence on the autoxidation of gallic acid in weakly alkaline aqueous solutions

    Science.gov (United States)

    Nikolić, G. M.; Veselinović, A. M.; Nikolić, R. S.; Mitić, S. S.

    2011-12-01

    Gallic acid autoxidation in weakly alkaline aqueous solutions was studied by UV-Vis spectrophotometry and ESR spectroscopy under various conditions. Lowering the pH value from 10 to 8.5 probably changes the mechanism of the autoxidation reaction as evidenced by the different time variations of UV-Vis spectra of solutions. The presence of Mg(II) ions greatly influences the autoxidation reaction at pH 8.5. Although the UV-Vis spectral changes with time follow the similar pattern during the gallic acid autoxidation at pH 10 and at pH 8.5 in the presence of Mg(II) ions, some small differences indicate that Mg(II) ions not only affect the electron density of absorbing species but also influence the overall mechanism of the autoxidation reaction. ESR spectra of free radials formed during the initial stage of gallic acid autoxidation at pH 8.5 in the presence of Mg(II) ions were recorded. Computer simulation of ESR spectra allows partial characterization of these free radicals.

  12. Li-Ion Cell Lot Testing and Flight Screening Results

    Science.gov (United States)

    2011-02-01

    than \\c7<. Results arc shown in Table 4. Table 4 Moli-Energ) Li-Ion Cell Weights Alter Vaeuun Leak Tesi Initial Final Final Weight Weight...All tested cells were within 95 *5! o\\ their initial capacity. Note: Cells C009 and C023 were misplaced following being weighed after the vac- uum

  13. Novel PVA/MOF Nanofibres: Fabrication, Evaluation and Adsorption of Lead Ions from Aqueous Solution

    Science.gov (United States)

    Shooto, Ntaote David; Dikio, Charity Wokwu; Wankasi, Donbebe; Sikhwivhilu, Lucky Mashudu; Mtunzi, Fanyana Moses; Dikio, Ezekiel Dixon

    2016-09-01

    Plain polyvinyl alcohol (PVA) nanofibres and novel polyvinyl alcohol benzene tetracarboxylate nanofibres incorporated with strontium, lanthanum and antimony ((PVA/Sr-TBC), (PVA/La-TBC) and (PVA/Sb-TBC)), respectively, where TBC is benzene 1,2,4,5-tetracarboxylate adsorbents, were fabricated by electrospinning. The as-prepared electrospun nanofibres were characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). Only plain PVA nanofibres followed the Freundlich isotherm with a correlation coefficient of 0.9814, while novel nanofibres (PVA/Sb-TBC, PVA/Sr-TBC and PVA/La-TBC) followed the Langmuir isotherm with correlation coefficients of 0.9999, 0.9994 and 0.9947, respectively. The sorption process of all nanofibres followed a pseudo second-order kinetic model. Adsorption capacity of novel nanofibres was twofold and more compared to that of plain PVA nanofibres. The thermodynamic studies: apparent enthalpy (Δ H°) and entropy (Δ S°), showed that the adsorption of Pb(II) onto nanofibres was spontaneous and exothermic. The novel nanofibres exhibited higher potential removal of Pb(II) ions than plain PVA nanofibres. Ubiquitous cations adsorption test was also investigated and studied.

  14. Sulfated chitosan/PVA absorbent membrane for removal of copper and nickel ions from aqueous solutions-Fabrication and sorption studies.

    Science.gov (United States)

    Abu-Saied, M A; Wycisk, Ryszard; Abbassy, Moustafa M; El-Naim, G Abd; El-Demerdash, F; Youssef, M E; Bassuony, H; Pintauro, Peter N

    2017-06-01

    Novel absorbents for the removal of Cu(2+) and Ni(2+) ions from aqueous solutions were prepared from solution cast sulfated chitosan/polyvinyl alcohol membranes (SCS/PVA) and their properties were investigated. FTIR, SEM, XRD and TGA analyses were used to determine membrane structure. The effect of environmental parameters on absorption was studied, including pH, contact time, temperature and the initial concentration of Ni(2+) and Cu(2+) ions. Freundlich and Langmuir absorption isotherms were fitted to experimental data and a pseudo-second order rate equation was employed to model the kinetics of uptake for several copper and nickel ion concentrations. The results indicate that the affinity of an SCS/PVA membrane for Cu(2+) ions was higher than that for Ni(2+) ions. The study demonstrated that the SCS/PVA system can be utilized as highly efficient sorbents, to extract Ni(2+) and Cu(2+) from aqueous feed solutions.

  15. Thermal Environmental Testing of NSTAR Engineering Model Ion Thrusters

    Science.gov (United States)

    Rawlin, Vincent K.; Patterson, Michael J.; Becker, Raymond A.

    1999-01-01

    NASA's New Millenium program will fly a xenon ion propulsion system on the Deep Space 1 Mission. Tests were conducted under NASA's Solar Electric Propulsion Technology Applications Readiness (NSTAR) Program with 3 different engineering model ion thrusters to determine thruster thermal characteristics over the NSTAR operating range in a variety of thermal environments. A liquid nitrogen-cooled shroud was used to cold-soak the thruster to -120 C. Initial tests were performed prior to a mature spacecraft design. Those results and the final, severe, requirements mandated by the spacecraft led to several changes to the basic thermal design. These changes were incorporated into a final design and tested over a wide range of environmental conditions.

  16. Ion collector design for an energy recovery test proposal with the negative ion source NIO1

    Energy Technology Data Exchange (ETDEWEB)

    Variale, V., E-mail: vincenzo.variale@ba.infn.it [INFN-BA, Via Orabona 4, I-70125 Bari (Italy); Cavenago, M. [INFN – LNL, viale dell’Università 2, I-35020 Legnaro (PD) (Italy); Agostinetti, P.; Sonato, P.; Zanotto, L. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy)

    2016-02-15

    Commercial viability of thermonuclear fusion power plants depends also on minimizing the recirculation power used to operate the reactor. The neutral beam injector (NBI) remains one of the most important method for plasma heating and control. For the future fusion power plant project DEMO, a NBI wall plug efficiency at least of 0.45 is required, while efficiency of present NBI project is about 0.25. The D{sup −} beam from a negative ion source is partially neutralized by a gas cell, which leaves more than 40% of energy in residual beams (D{sup −} and D{sup +}), so that an ion beam energy recovery system can significantly contribute to optimize efficiency. Recently, the test negative ion source NIO1 (60 keV, 9 beamlets with 15 mA H{sup −} each) has been designed and built at RFX (Padua) for negative ion production efficiency and the beam quality optimization. In this paper, a study proposal to use the NIO1 source also for a beam energy recovery test experiment is presented and a preliminary design of a negative ion beam collector with simulations of beam energy recovery is discussed.

  17. Ion collector design for an energy recovery test proposal with the negative ion source NIO1.

    Science.gov (United States)

    Variale, V; Cavenago, M; Agostinetti, P; Sonato, P; Zanotto, L

    2016-02-01

    Commercial viability of thermonuclear fusion power plants depends also on minimizing the recirculation power used to operate the reactor. The neutral beam injector (NBI) remains one of the most important method for plasma heating and control. For the future fusion power plant project DEMO, a NBI wall plug efficiency at least of 0.45 is required, while efficiency of present NBI project is about 0.25. The D(-) beam from a negative ion source is partially neutralized by a gas cell, which leaves more than 40% of energy in residual beams (D(-) and D(+)), so that an ion beam energy recovery system can significantly contribute to optimize efficiency. Recently, the test negative ion source NIO1 (60 keV, 9 beamlets with 15 mA H(-) each) has been designed and built at RFX (Padua) for negative ion production efficiency and the beam quality optimization. In this paper, a study proposal to use the NIO1 source also for a beam energy recovery test experiment is presented and a preliminary design of a negative ion beam collector with simulations of beam energy recovery is discussed.

  18. Preparation and characterization of novel P(HEA/IA) hydrogels for Cd{sup 2+} ion removal from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Antić, Katarina M.; Babić, Marija M.; Vuković, Jovana J. Jovašević [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, Belgrade (Serbia); Vasiljević-Radović, Dana G. [Institute for Chemistry, Technology and Metallurgy, University of Belgrade, Njegoseva 12, Belgrade (Serbia); Onjia, Antonije E. [Vinca Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, Belgrade (Serbia); Filipović, Jovanka M. [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, Belgrade (Serbia); Tomić, Simonida Lj., E-mail: simonida@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, Belgrade (Serbia)

    2015-05-30

    Highlights: • Hydrogels based on 2-hydroxyethyl acrylate and itaconic acid (P(HEA/IA)) were synthesized. • Cd{sup 2+} ion removal was investigated. • The surface and cross-section of hydrogels were observed by SEM and AFM. • The adsorption kinetics and isotherms of cadmium ions on the hydrogel were studied. • Approximately 95% of the adsorbed cadmium could be recovered by 0.1 M HNO{sub 3} treatment. - Abstract: Series of novel hydrogels based on 2-hydroxyethyl acrylate (HEA) and itaconic acid (IA), P(HEA/IA) copolymers, were prepared by free radical cross-linking copolymerization and investigated as potential adsorbents for Cd{sup 2+} removal from aqueous solution. The hydrogels before and after Cd{sup 2+} adsorption were characterized using FTIR, DSC, SEM/EDX, AFM and DMA analysis. The swelling results showed that these hydrogels are pH and temperature sensitive. In order to evaluate adsorption behavior of samples various factors affecting the Cd{sup 2+} uptake behavior, such as: contact time, temperature, pH, ionic strength, adsorbent weight, competitive ions and initial concentration of the metal ions were investigated. Five adsorption isotherms and two kinetic models were studied. The adsorption behavior can be very well described by the pseudo-second order kinetic model and Langmuir isotherm. Multicomponent adsorption studies revealed that adsorption of cadmium depends on the type of metal ions present in the system. Desorption studies showed that hydrogel can be reused three times with only 15% loss of adsorption capacity. All results indicate that the sample with the highest IA content is the most promising adsorbent for Cd{sup 2+} removal.

  19. Radiation microscope for SEE testing using GeV ions.

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, Barney Lee; Knapp, James Arthur; Rossi, Paolo; Hattar, Khalid M.; Vizkelethy, Gyorgy; Brice, David Kenneth; Branson, Janelle V.

    2009-09-01

    Radiation Effects Microscopy is an extremely useful technique in failure analysis of electronic parts used in radiation environment. It also provides much needed support for development of radiation hard components used in spacecraft and nuclear weapons. As the IC manufacturing technology progresses, more and more overlayers are used; therefore, the sensitive region of the part is getting farther and farther from the surface. The thickness of these overlayers is so large today that the traditional microbeams, which are used for REM are unable to reach the sensitive regions. As a result, higher ion beam energies have to be used (> GeV), which are available only at cyclotrons. Since it is extremely complicated to focus these GeV ion beams, a new method has to be developed to perform REM at cyclotrons. We developed a new technique, Ion Photon Emission Microscopy, where instead of focusing the ion beam we use secondary photons emitted from a fluorescence layer on top of the devices being tested to determine the position of the ion hit. By recording this position information in coincidence with an SEE signal we will be able to indentify radiation sensitive regions of modern electronic parts, which will increase the efficiency of radiation hard circuits.

  20. Removal of cobalt ions from aqueous solution by an amination graphene oxide nanocomposite.

    Science.gov (United States)

    Fang, Fang; Kong, Lingtao; Huang, Jiarui; Wu, Shibiao; Zhang, Kaisheng; Wang, Xuelong; Sun, Bai; Jin, Zhen; Wang, Jin; Huang, Xing-Jiu; Liu, Jinhuai

    2014-04-15

    A newly designed amination graphene oxide (GO-NH2), a superior adsorption capability to that of activated carbon, was fabricated by graphene oxide (GO) combining with aromatic diazonium salt. The resultant GO-NH2 maintained a high surface area of 320 m(2)/g. When used as an adsorbent, the GO-NH2 demonstrated a very quick adsorption property for the removal of Co(II) ions, more than 90% of Co(II) ions could be removed within 5 min for dilute solutions at 0.3g/L adsorbent dose. The adsorption capability approaches 116.35 mg/g, which is one of the highest capabilities of today's materials. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggested that the Co(II) ions adsorption on GO-NH2 was a spontaneous process. Considering the superior adsorption capability, the GO-NH2 filter membrane was fabricated for the removal of Co(II) ions. Membrane filtration experiments revealed that the removal capabilities of the materials for cobalt ions depended on the membrane's thickness, flow rate and initial concentration of Co(II) ions. The highest percentage removal of Co(II) exceeds 98%, indicating that the GO-NH2 is one of the very suitable membrane materials in environmental pollution management.

  1. Application of Corn Cob as a Natural Adsorbent for the Removal of Mn (Vii Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Fariba Norozi

    2016-08-01

    Full Text Available In this Work, We have studied the adsorption of the isotherm of Mn(VII, on Corn cob from aqueous solutions. The effects of pH, initial metal ion concentration, contact time, Corn cobdosage and temperature on the adsorption performance of Corn cob for Mn(VII ions were examined by batch method. Increasing the Mn(VII initial concentration declines the Mn(VII adsorption rate investigated through adsorption Mn(VII removal at pH=4 condition for tC=60 min in equilibrium-batch mode system. The adsorption equilibrium isotherms were fitted by Freundlich and Langmuir models. It was found that the Langmuir model described the adsorption process better than the Freundlich isotherm,(R2=0.9854, thus indicating the applicability of mono layer coverage of Mn(VII ion on Corn cob surface.The relationship between thermodynamic parameters was used to predict the absorption process. Thermodynamic analysis showed that the adsorption process was endothermic and spontaneous in nature.

  2. Pengaruh Konsentrasi Karbon Terhadap Performa Elektrokimia Anoda Liti2(Po43 Untuk Aplikasi Baterai Ion Lithium Tipe Aqueous Elektrolit

    Directory of Open Access Journals (Sweden)

    Zeddy Argasani

    2014-09-01

    Full Text Available Salah satu sistem penyimpanan energi terbarukan yang banyak digunakan dewasa ini adalah rechargeable lithium-ion battery. Pada rechargeable lithium-ion battery terdapat 4 bagian utama yang salah satunya adalah bagian anoda. Anoda yang dipakai adalah LiTi2(PO43 dengan tipe NASICON yang dilakukan proses conductive coating yang menggunakan sukrosa dengan pemanasan 600˚C selama 3 jam didalam atmosfer argon untuk membentuk coating karbon LiTi2(PO43/C sehingga meningkatkan performa elektrokimia yaitu dalam hal kapasitas material LiTi2(PO43. Hasil persentase berat karbon yang terdapat pada LiTi2(PO43/C diidentifikasi dengan Carbon Analyzer didapat dengan kadar karbon 8%, 13%, dan 17.2%. Dari hasil CV, penambahan karbon coating dapat meningkatkan stabilitas, konduktifitas elektronik, kapasitas, dan performa siklik material LiTi2(PO43/C di dalam aqueous elektrolit. Pada hasil charge-discharge, penambahan karbon coating yang tepat dapat membawa ion lithium berinterkalasi secara mudah dan didapatkan kapasitas charge tertinggi dari LiTi2(PO43 8% C yaitu sebesar 45.9 mAh/g dengan kapasitas yang hilang sebesar 53.4% setelah 100 siklik.

  3. Ion distributions at charged aqueous surfaces: Synchrotron X-ray scattering studies

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Wei [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Surface sensitive synchrotron X-ray scattering studies were performed to obtain the distribution of monovalent ions next to a highly charged interface at room temperature. To control surface charge density, lipids, dihexadecyl hydrogen-phosphate (DHDP) and dimysteroyl phosphatidic acid (DMPA), were spread as monolayer materials at the air/water interface, containing CsI at various concentrations. Five decades in bulk concentrations (CsI) are investigated, demonstrating that the interfacial distribution is strongly dependent on bulk concentration. We show that this is due to the strong binding constant of hydronium H3O+ to the phosphate group, leading to proton-transfer back to the phosphate group and to a reduced surface charge. Using anomalous reflectivity off and at the L3 Cs+ resonance, we provide spatial counterion (Cs+) distributions next to the negatively charged interfaces. The experimental ion distributions are in excellent agreement with a renormalized surface charge Poisson-Boltzmann theory for monovalent ions without fitting parameters or additional assumptions. Energy Scans at four fixed momentum transfers under specular reflectivity conditions near the Cs+ L3 resonance were conducted on 10-3 M CsI with DHDP monolayer materials on the surface. The energy scans exhibit a periodic dependence on photon momentum transfer. The ion distributions obtained from the analysis are in excellent agreement with those obtained from anomalous reflectivity measurements, providing further confirmation to the validity of the renormalized surface charge Poisson-Boltzmann theory for monovalent ions. Moreover, the dispersion corrections f0 and f00 for Cs+ around L3 resonance, revealing the local environment of a Cs+ ion in the solution at the interface, were extracted simultaneously with output of ion distributions.

  4. Application of Buckmaster Electrolyte Ion Leakage Test to Woody Biofuel Feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Thomas F [Forest Concepts, LLC; Dooley, James H [Forest Concepts, LLC

    2014-08-28

    In an earlier ASABE paper, Buckmaster reported that ion conductivity of biomass leachate in aqueous solution was directly correlated with activity access to plant nutrients within the biomass materials for subsequent biological or chemical processing. The Buckmaster test involves placing a sample of the particles in a beaker of constant-temperature deionized water and monitoring the change in electrical conductivity over time. We adapted the Buckmaster method to a range of woody biomass and other cellulosic bioenergy feedstocks. Our experimental results suggest differences of electrolyte leakage between differently processed woody biomass particles may be an indicator of their utility for conversion in bioenergy processes. This simple assay appears to be particularly useful to compare different biomass comminution techniques and particle sizes for biochemical preprocessing.

  5. Consideration of fractal and ion-water cooperative interactions in aqueous Na2SO4 and K2SO4 solutions by dielectric relaxation spectroscopy

    Science.gov (United States)

    Liu, Shuang; Jia, Guo-zhu; Zhang, Shu

    2016-01-01

    This paper presents the analysis of the fractal and the ion-water cooperative interactions in aqueous Na2SO4 and K2SO4 solutions underlying the Cole-Cole symmetrical broadening and depicts the Cole-Cole relaxation process. Fractal analysis with α(ln(τ)) diagram from dielectric relaxation spectroscopy (DRS) draws a consistent microscopic picture of ion-water cooperative interactions in aqueous Na2SO4 and K2SO4 solutions. The density of the water molecules perturbed by ions in the hydration shell almost linearly increases with salt concentrations. The water molecules network perturbed by ions contributing to dielectric constant beyond the first hydration shell is obtained.

  6. CdS quantum dots as fluorescence probes for the sensitive and selective detection of highly reactive HSe- ions in aqueous solution.

    Science.gov (United States)

    Wu, Chuan-Liu; Zhao, Yi-Bing

    2007-06-01

    Water-soluble cadmium sulfide (CdS) quantum dots (QDs) capped by mercaptoacetic acid were synthesized by aqueous-phase arrested precipitation, and characterized by transmission electron microscopy, spectrofluorometry, and UV-Vis spectrophotometry. The prepared luminescent water-soluble CdS QDs were evaluated as fluorescence probes for the detection of highly reactive hydrogen selenide ions (HSe(-) ions). The quenching of the fluorescence emission of CdS QDs with the addition of HSe(-) ions is due to the elimination of the S(2-) vacancies which are luminescence centers. Quantitative analysis based on chemical interaction between HSe(-) ions and the surface of CdS QDs is very simple, easy to develop, and has demonstrated very high sensitivity and selectivity features. The effect of foreign ions (common anions and biologically relevant cations) on the fluorescence of the CdS QDs was examined to evaluate the selectivity. Only Cu(2+) and S(2-) ions exhibit significant effects on the fluorescence of CdS QDs. With the developed method, we are able to determine the concentration of HSe(-) ions in the range from 0.10 to 4.80 micromol L(-1), and the limit of detection is 0.087 micromol L(-1). The proposed method was successfully applied to monitor the obtained HSe(-) ions from the reaction of glutathione with selenite. To the best of our knowledge, this is the first report on fluorescence analysis of HSe(-) ions in aqueous solution.

  7. Kinetic Approach to the Mechanism of Redox Reaction of Pyrocatechol Violet and Nitrite Ion in Aqueous Hydrochloric Acid

    Directory of Open Access Journals (Sweden)

    A. Adetoro

    2011-10-01

    Full Text Available The kinetics of the oxidation of Pyrocatechol violet (PCVH by nitrite ion (NO2- in aqueous acidic medium has been studied at 24±1ºC, I = 0.50 mol/dm3(NaCl, [H+] = 1.0×10-3 mol/dm3. The reaction is first order to [PCVH] and half order to [NO2-]. The redox reaction displayed a 1:1 stoichiometry and obeys the rate law: d[PCVH]/dt = (a + b[H+] [PCVH][NO2-]½. The second-order rate constant increases with increase in acid concentration and ionic strength. This system displayed positive salt effect while spectroscopic investigation and Michaelis-Menten plot showed evidence of intermediate complex formation in the course of the reaction. A plausible mechanism has been proposed for the reaction.

  8. Biosorption Performance of Biodegradable Polymer Powders for the Removal of Gallium(III ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Lee Ching-Hwa

    2015-09-01

    Full Text Available Gallium (Ga is considered an important element in the semiconducting industry and as the lifespan of electronic products decrease annually Ga-containing effluent has been increasing. The present study investigated the use of biodegradable polymer powders, crab shell and chitosan, in the removal of Ga(III ions from aqueous solution. Ga(III biosorption was modeled to Lagergren-first, pseudo-second order and the Weber-Morris models. Equilibrium data was modeled to the Langmuir, Freundlich and Langmuir-Freundlich adsorption isotherms to determine the probable biosorption behavior of Ga(III with the biosorbents. The biosorbents were investigated by Fourier Transform Infrared Spectroscopy, X-ray Diffraction and Scanning Electron Microscopy/Energy Dispersive Spectra analysis.

  9. Influence of Operating Conditions on the Removal Cd Ions from Aqueous Media by Adsorption Using Chlamydomonas Reinhardtii

    Institute of Scientific and Technical Information of China (English)

    Jiang Yongbin; Zhu Yi; Ji Hongbing

    2010-01-01

    Chlamydomonas reinhardtii(C.reinhardtii)was used to study adsorption of cadmium(Cd)from aqueous media within various experimental conditions.Results showed that the adsorption process was very fast,with most of the adsorption occurring within30 min of contact time and the equilibrium state was reached in about 60 min.The adsorption ability of the algae increases with the increasing adsorptions sites on cells.Maximum adsorption was observed at the initial Cd concentration of 100 mg/L and pH 6.0.The adsorption was markedly inhibited in the presence of calcium and magnesium ions at 10 mM and the Cd removal efficiency was reduced by 16.54% and 14.99% respectively.This study would be a finding of note with regard to practical wastewater treatment.

  10. Sodium Chloride interaction with solvated and crystalline cellulose : sodium ion affects the tetramer and fibril in aqueous solution

    CERN Document Server

    Bellesia, Giovanni

    2013-01-01

    Inorganic salts are a natural component of biomass which have a significant effect on the product yields from a variety of biomass conversion processes. Understanding their effect on biomass at the microscopic level can help discover their mechanistic role. We present a study of the effect of aqueous sodium chloride (NaCl) on the largest component of biomass, cellulose, focused on the thermodynamic and structural effect of a sodium ion on the cellulose tetramer, and fibril. Replica exchange molecular dynamics simulations of a cellulose tetramer reveal a number of preferred cellulose-Na contacts and bridging positions. Large scale MD simulations on a model cellulose fibril find that Na+ perturbs the hydroxymethyl rotational state population and consequently disrupts the "native" hydrogen bonding network.

  11. Possible time-dependent effect of ions and hydrophilic surfaces on the electrical conductivity of aqueous solutions.

    Science.gov (United States)

    Verdel, Nada; Jerman, Igor; Krasovec, Rok; Bukovec, Peter; Zupancic, Marija

    2012-01-01

    The purpose of this work was to determine the influence of mechanical and electrical treatment on the electrical conductivity of aqueous solutions. Solutions were treated mechanically by iteration of two steps: 1:100 dilution and vigorous shaking. These two processes were repeated until extremely dilute solutions were obtained. For electrical treatment the solutions were exposed to strong electrical impulses. Effects of mechanical (as well as electrical) treatment could not be demonstrated using electrical conductivity measurements. However, significantly higher conductivity than those of the freshly prepared chemically analogous solutions was found in all aged solutions except for those samples stored frozen. The results surprisingly resemble a previously observed weak gel-like behavior in water stored in closed flasks. We suggest that ions and contact with hydrophilic glass surfaces could be the determinative conditions for the occurrence of this phenomenon.

  12. Pengaruh Konsentrasi Karbon Terhadap Performa Elektrokimia Katoda Lifepo4 Untuk Aplikasi Baterai Lithium Ion Tipe Aqueous Electrolyte

    Directory of Open Access Journals (Sweden)

    Ade Okta Yurwendra

    2014-09-01

    Full Text Available Baterai lithium ion rechargeable telah dipertimbangkan sebagai sebuah sumber tenaga listrik yang digunakan untuk berbagai aplikasi. LiFePO4 yang digunakan sebagai katoda, dipilih karena memiliki sifat yang ramah lingkungan tetapi memiliki konduktivitas yang lemah. LiFePO4 dilakukan proses konduktif coating menggunakan sukrosa dengan pemanasan 600oC selama 3 jam didalam atmosfer argon untuk membentuk karbon coating LiFePO4 (LiFePO4/C dengan variasi persentase berat karbon 9%, 14.5%, dan 17.8% karbon. Dari analisis cyclic voltammetry penambahan karbon coating dapat meningkatkan stabilitas didalam aqueous electrolyte. Hasil galvanostatic charge/discharge didapatkan hasil terbaik pada LiFePO4/C dengan persentase berat karbon 9% dengan kapasitas discharge 13.3 mAhg-1 dan mengalami penurunan kapasitas sebesar 2.2% setelah cycle ke 100. Penambahan karbon yang berlebihan menurunkan kapasitas LiFePO4

  13. Synthesis of DNPH/SDS/Fe3O4 Nanoparticles for Removal of Cr (VI Ions From Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Soheil Sobhanardakani

    2016-06-01

    Full Text Available In this study, sodium dodecyl sulfate (SDS coated magnetite modified with 2, 4-Dinitrophenylhydrazine was used to remove Cr (VI ions from aqueous solution. The modified magnetite nanoparticles were characterized by X-ray diffraction (XRD analysis, Fourier transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM, and SEM–EDXS measurement. The synthesized nanoparticles exhibited a high surface area of 75.5 m2 g−1 and were of 20 - 35 nm in particle size. The effects of parameters, including pH, dose of adsorbent, temperature and contact time were investigated to find the optimum adsorption conditions. Adsorption data fits well with the Langmuir isotherm model with a maximum adsorption capacity (qm and a Langmuir adsorption equilibrium constant (b of 169.5 mg g-1 and 0.168 L mg-1, respectively. The adsorption kinetic agrees well with pseudo-second-order model.

  14. An Optical Fiber-Based Sensor Array for the Monitoring of Zinc and Copper Ions in Aqueous Environments

    Directory of Open Access Journals (Sweden)

    Steven Kopitzke

    2014-02-01

    Full Text Available Copper and zinc are elements commonly used in industrial applications as aqueous solutions. Before the solutions can be discharged into civil or native waterways, waste treatment processes must be undertaken to ensure compliance with government guidelines restricting the concentration of ions discharged in solution. While currently there are methods of analysis available to monitor these solutions, each method has disadvantages, be it high costs, inaccuracy, and/or being time-consuming. In this work, a new optical fiber-based platform capable of providing fast and accurate results when performing solution analysis for these metals is described. Fluorescent compounds that exhibit a high sensitivity and selectivity for either zinc or copper have been employed for fabricating the sensors. These sensors demonstrated sub-part-per-million detection limits, 30-second response times, and the ability to analyze samples with an average error of under 10%. The inclusion of a fluorescent compound as a reference material to compensate for fluctuations from pulsed excitation sources has further increased the reliability and accuracy of each sensor. Finally, after developing sensors capable of monitoring zinc and copper individually, these sensors are combined to form a single optical fiber sensor array capable of simultaneously monitoring concentration changes in zinc and copper in aqueous environments.

  15. Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage

    Science.gov (United States)

    Shan, Xiaoqiang; Charles, Daniel S.; Lei, Yinkai; Qiao, Ruimin; Wang, Guofeng; Yang, Wanli; Feygenson, Mikhail; Su, Dong; Teng, Xiaowei

    2016-11-01

    Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost and environmental friendliness. However, their applications have been limited by a narrow potential window (~1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here we report the formation of layered Mn5O8 pseudocapacitor electrode material with a well-ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable potential window of 3.0 V in an aqueous electrolyte, as well as high energy and power performance, nearly 100% coulombic efficiency and 85% energy efficiency after 25,000 charge-discharge cycles. The interplay between hydroxylated interphase on the surface and the unique bivalence structure of Mn5O8 suppresses the gas evolution reactions, offers a two-electron charge transfer via Mn2+/Mn4+ redox couple, and provides facile pathway for Na-ion transport via intra-/inter-layer defects of Mn5O8.

  16. Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage.

    Science.gov (United States)

    Shan, Xiaoqiang; Charles, Daniel S; Lei, Yinkai; Qiao, Ruimin; Wang, Guofeng; Yang, Wanli; Feygenson, Mikhail; Su, Dong; Teng, Xiaowei

    2016-11-15

    Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost and environmental friendliness. However, their applications have been limited by a narrow potential window (∼1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here we report the formation of layered Mn5O8 pseudocapacitor electrode material with a well-ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable potential window of 3.0 V in an aqueous electrolyte, as well as high energy and power performance, nearly 100% coulombic efficiency and 85% energy efficiency after 25,000 charge-discharge cycles. The interplay between hydroxylated interphase on the surface and the unique bivalence structure of Mn5O8 suppresses the gas evolution reactions, offers a two-electron charge transfer via Mn(2+)/Mn(4+) redox couple, and provides facile pathway for Na-ion transport via intra-/inter-layer defects of Mn5O8.

  17. Ion pair formation in copper sulfate aqueous solutions at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Mendez De Leo, Lucila P. [Unidad de Actividad Quimica, Comision Nacional de Energia, Avenida del Libertador 8250, 1429 Ciudad de Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad Nacional General San Martin, Alem 3901, 1653 Villa Ballester (Argentina); Bianchi, Hugo L. [Unidad de Actividad Quimica, Comision Nacional de Energia, Avenida del Libertador 8250, 1429 Ciudad de Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad Nacional General San Martin, Alem 3901, 1653 Villa Ballester (Argentina); Fernandez-Prini, Roberto [Unidad de Actividad Quimica, Comision Nacional de Energia, Avenida del Libertador 8250, 1429 Ciudad de Buenos Aires (Argentina) and INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon II, 1428 Ciudad de Buenos Aires (Argentina)]. E-mail: rfprini@cnea.gov.ar

    2005-05-15

    Ionic association between Cu{sup 2+}(aq) and SO42-(aq) has been studied in the temperature range (298 to 473) K using a spectrophotometric technique. Experiments were designed to minimize the contribution of other protolytic equilibria in solution. The values of the ionic association equilibrium constant at different temperatures and pressures were fitted to an appropriate equation that allows the calculation of the thermodynamic quantities for states close to the saturation line. Using Bjerrum's model for ionic association evidence for two ion pair populations was obtained. The process of ion pairing is discussed and a possibility to reconcile the continuum model (Bjerrum) with molecular simulation results is suggested.

  18. Ion Exchange Testing with SRF Resin FY2012

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.

    2013-06-11

    Ion exchange using spherical resorcinol-formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection (DOE-ORP) for use in the Pretreatment Facility (PTF) of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in at-tank deployment. Numerous studies have shown SRF resin to be effective for removing 137Cs from a wide variety of actual and simulated tank waste supernatants (Adamson et al. 2006; Blanchard et al. 2008; Burgeson et al. 2004; Duignan and Nash 2009; Fiskum et al. 2006a; Fiskum et al. 2006b; Fiskum et al. 2006c; Fiskum et al. 2007; Hassan and Adu-Wusu 2003; King et al. 2004; Nash et al. 2006). Prior work at the Pacific Northwest National Laboratory (PNNL) has focused primarily on the loading behavior for 4 to 6 M Na solutions at 25 to 45°C. Recent proposed changes to the WTP ion exchange process baseline indicate that loading may include a broader range of sodium molarities (0.1 to 8 M) and higher temperatures (50°C) to alleviate post-filtration precipitation issues. This report discusses ion exchange loading kinetics testing activities performed in accordance with Test Plan TP-WTPSP-002, Rev. 3.0 , which was prepared and approved in response to the Test Specification 24590 PTF-TSP-RT-09-002, Rev. 0 (Lehrman 2010) and Test Exception 24590 PTF TEF RT-11-00003, Rev. 0 (Meehan 2011). This testing focused on column tests evaluating the impact of elevated temperature on resin degradation over an extended period of time and batch contacts evaluating the impact on Cs loading over a broad range of sodium concentrations (0.1 to 5 M). These changes may be required to alleviate post-filtration precipitation issues and broaden the data range of SRF resin loading under the conditions expected with the new equipment and process changes.

  19. Molecular dynamics investigation of desorption and ion separation following picosecond infrared laser (PIRL) ablation of an ionic aqueous protein solution.

    Science.gov (United States)

    Zou, J; Wu, C; Robertson, W D; Zhigilei, L V; Miller, R J D

    2016-11-28

    Molecular dynamics simulations were performed to characterize the ablation process induced by a picosecond infrared laser (PIRL) operating in the regime of desorption by impulsive vibrational excitation (DIVE) of a model peptide (lysozyme)/counter-ion system in aqueous solution. The simulations were performed for ablation under typical experimental conditions found within a time-of-flight mass spectrometer (TOF-MS), that is in vacuum with an applied electric field (E = ± 10(7) V/m), for up to 2 ns post-ablation and compared to the standard PIRL-DIVE ablation condition (E = 0 V/m). Further, a simulation of ablation under an extreme field condition (E = 10(10) V/m) was performed for comparison to extend the effective dynamic range of the effect of the field on charge separation. The results show that the plume dynamics were retained under a typical TOF-MS condition within the first 1 ns of ablation. Efficient desorption was observed with more than 90% of water molecules interacting with lysozyme stripped off within 1 ns post-ablation. The processes of ablation and desolvation of analytes were shown to be independent of the applied electric field and thus decoupled from the ion separation process. Unlike under the extreme field conditions, the electric field inside a typical TOF-MS was shown to modify the ions' motion over a longer time and in a soft manner with no enhancement to fragmentation observed as compared to the standard PIRL-DIVE. The study indicates that the PIRL-DIVE ablation mechanism could be used as a new, intrinsically versatile, and highly sensitive ion source for quantitative mass spectrometry.

  20. Molecular dynamics investigation of desorption and ion separation following picosecond infrared laser (PIRL) ablation of an ionic aqueous protein solution

    Science.gov (United States)

    Zou, J.; Wu, C.; Robertson, W. D.; Zhigilei, L. V.; Miller, R. J. D.

    2016-11-01

    Molecular dynamics simulations were performed to characterize the ablation process induced by a picosecond infrared laser (PIRL) operating in the regime of desorption by impulsive vibrational excitation (DIVE) of a model peptide (lysozyme)/counter-ion system in aqueous solution. The simulations were performed for ablation under typical experimental conditions found within a time-of-flight mass spectrometer (TOF-MS), that is in vacuum with an applied electric field (E = ± 107 V/m), for up to 2 ns post-ablation and compared to the standard PIRL-DIVE ablation condition (E = 0 V/m). Further, a simulation of ablation under an extreme field condition (E = 1010 V/m) was performed for comparison to extend the effective dynamic range of the effect of the field on charge separation. The results show that the plume dynamics were retained under a typical TOF-MS condition within the first 1 ns of ablation. Efficient desorption was observed with more than 90% of water molecules interacting with lysozyme stripped off within 1 ns post-ablation. The processes of ablation and desolvation of analytes were shown to be independent of the applied electric field and thus decoupled from the ion separation process. Unlike under the extreme field conditions, the electric field inside a typical TOF-MS was shown to modify the ions' motion over a longer time and in a soft manner with no enhancement to fragmentation observed as compared to the standard PIRL-DIVE. The study indicates that the PIRL-DIVE ablation mechanism could be used as a new, intrinsically versatile, and highly sensitive ion source for quantitative mass spectrometry.

  1. The Application of Response Surface Methodology for Lead Ion Removal from Aqueous Solution Using Intercalated Tartrate-Mg-Al Layered Double Hydroxides

    Directory of Open Access Journals (Sweden)

    Yamin Yasin

    2013-01-01

    Full Text Available Layered double hydroxide intercalated with tartrate (tartrate-Mg-Al was used as an adsorbent to remove lead ions from aqueous solutions. The effects of various optimization parameters such as contact time, solution pH, lead ion concentrations, and adsorbent dosage were investigated by the use of Response Surface Methodology (RSM. The Response Surface Methodology (RSM based on a four-level four-variable Central Composite Rotatable Design (CCRD was employed to evaluate the interactive effects of the various optimization parameters. The parameters were contact time (6–10 h, solution pH (1–3, adsorbent dosage (0.06–0.1 g, and lead ion concentrations (10–30 mg/L. The percentage of lead ions removal for each of the parameters studied was determined by Inductively Coupled Plasma-Optical Emission Spectrophotometer. Simultaneously by increasing contact time and amount of dosage of tartrate-Mg-Al used the percentage of lead ions removal from aqueous solution will increase; however, the percentage removal decreases with an increase in pH and concentrations of lead ions. The experimental percentage removal recorded under optimum conditions was compared well with the maximum predicted value from the RSM, which suggest that Central Composite Rotatable Design of RSM can be used to study the removal of lead from aqueous solution by the use of tartrate-Mg-Al as an adsorbent.

  2. Biosorption of copper ions from aqueous solutions by Spirulina platensis biomass

    Directory of Open Access Journals (Sweden)

    Ali A. Al-Homaidan

    2014-01-01

    Full Text Available In this study, the economically important micro-alga (cyanobacterium Spirulina platensis was used as biosorbent for the removal of copper from aqueous solutions. The cyanobacterium was exposed to various concentrations of copper and adsorption of copper by the biomass was evaluated under different conditions that included pH, contact time, temperature, concentration of adsorbate and the concentration of dry biomass. Increased adsorption of copper by the non-living biomass was recorded with gradually increasing pH, and a maximal uptake by the biomass was observed at pH 7. The adsorption of copper was found to increase gradually along with decrease in biomass concentration. Biosorption was found to be at a maximum (90.6%, in a solution containing 100 mg copper/L, at pH 7, with 0.050 g dry biomass and at 37 °C with 90 min of contact time. Analysis of the spectrum obtained with atomic absorption spectrophotometer (AAS, indicated that the adsorbent has a great potential to remove copper from aqueous media contributing to an eco-friendly technology for efficient bioremediation in the natural environment.

  3. Removal of lead ions from aqueous solution by the dried aquatic plant, Lemna perpusilla Torr.

    Science.gov (United States)

    Tang, Yankui; Chen, Ling; Wei, Xingren; Yao, Qiuyan; Li, Ting

    2013-01-15

    The aquatic plant, Lemna perpusilla Torr. strain, was dried, pulverized and used for Pb(II) removal from aqueous solution. Batch experiments were conducted to investigate the effects of pH, contact time, initial metal concentration and temperature on Pb(II) adsorption. A dose of 4 g L(-1) of dried L. perpusilla in a solution with an initial pH of 4.6, an initial Pb(II) concentration of 50 mg L(-1) and a contact time of 210 min resulted in the maximum Pb(II) removal efficiency (above 95%). The equilibrium adsorption capacities increased with increasing initial Pb(II) concentration. The adsorption isotherm was better described by a Langmuir model rather than a Freundlich model. Further, the adsorption kinetics followed a pseudo-second-order model. An FTIR examination revealed changes between the natural and Pb(II)-loaded plant material. Scanning electron micrograph (SEM) also revealed changes in the surface morphology of the biomass as a result of lead adsorption. Based on these results, it can be concluded that the dried L. perpusilla is effective in removing lead from aqueous solution and merits consideration for scaled-up trials.

  4. Synthesis and optical properties of type II CdTe/CdS core/shell quantum dots in aqueous solution via successive ion layer adsorption and reaction

    NARCIS (Netherlands)

    Zeng, Q.; Kong, X.; Sun, Y.; Zhang, Y.; Tu, L.; Zhao, J.; Zhang, H.

    2008-01-01

    3-Mercaptopropionic acid stabilized CdTe/CdS core/shell quantum dots (QDs) were prepared in an aqueous solution following the synthetic route of successive ion layer adsorption and reaction. The photoluminescence quantum yield of the CdTe QDs could reach 40%, from 8% of the bare core, via the contro

  5. PAH toxicity at aqueous solubility in the fish embryo test with Danio rerio using passive dosing

    DEFF Research Database (Denmark)

    Seiler, Thomas-Benjamin; Best, Nina; Fernqvist, Margit Møller

    2014-01-01

    to animal testing in (eco)toxicology. However, for hydrophobic organic chemicals it remains a technical challenge to ensure constant freely dissolved concentration at the maximum exposure level during such biotests. Passive dosing with PDMS silicone was thus applied to control the freely dissolved...... further data to support the close relationship between the chemical activity and the toxicity of hydrophobic organic compounds. Passive dosing from PDMS silicone enabled reliable toxicity testing of (highly) hydrophobic substances at aqueous solubility, providing a practical way to control toxicity...... without direct contact to the silicone surface showed similar mortalities as those exposed with direct contact to the silicone. Silicone oil overlaying the water phase as a novel passive dosing phase had no observable effects on the development of the fish embryos until hatching. This study provides...

  6. Sorptive potential of sunflower stem for Cr(III) ions from aqueous solutions and its kinetic and thermodynamic profile.

    Science.gov (United States)

    Malik, Ummat Rasul; Hasany, Syed Moosa; Subhani, Muhammad Sadiq

    2005-03-31

    The sorptive potential of sunflower stem (180-300mum) for Cr(III) ions has been investigated in detail. The maximum sorption (>/=85%) of Cr(III) ions (70.2muM) has been accomplished using 30mg of high density sunflower stem in 10min from 0.001M nitric and 0.0001M hydrochloric acid solutions. The accumulation of Cr(III) ions on the sorbent follows Dubinin-Radushkevich (D-R), Freundlich and Langmuir isotherms. The isotherm yields D-R saturation capacity X(m)=1.60+/-0.23mmolg(-1), beta=-0.00654+/-0.00017kJ(2)mol(-2), mean free energy E=8.74+/-0.12kJmol(-1), Freundlich sorption capacity K(F)=0.24+/-0.11molg(-1), 1/n=0.90+/-0.04 and of Langmuir constant K(L)=6800+/-600dm(3)mol(-1) and C(m)=120+/-18micromolg(-1). The variation of sorption with temperature (283-323K) gives DeltaH=-23.3+/-0.8kJmol(-1), DeltaS=-64.0+/-2.7Jmol(-1)K(-1) and DeltaG(298k)=-4.04+/-0.09kJmol(-1). The negative enthalpy and free energy envisage exothermic and spontaneous nature of sorption, respectively. Bisulphate, Fe(III), molybdate, citrate, Fe(II), Y(III) suppress the sorption significantly. The selectivity studies indicate that Cr(III), Eu(III) and Tb(III) ions can be separated from Tc(VII) and I(I). Sunflower stem can be used for the preconcentration and removal of Cr(III) ions from aqueous medium. This cheaper and novel sorbent has potential applications in analytical and environmental chemistry, in water decontamination, industrial waste treatment and in pollution abatement. A possible mechanism of biosorption of Cr(III) ions onto the sunflower stem has been proposed.

  7. Removal of cesium ions from aqueous solution by adsorption onto local Taiwan laterite

    Energy Technology Data Exchange (ETDEWEB)

    Wang, T.-H. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Li, M.-H. [Institute of Hydrological Sciences, National Central University, Jungli 320, Taiwan (China); Yeh, W.-C.; Wei, Y.-Y. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 300, Taiwan (China); Teng, S.-P. [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 300, Taiwan (China); Institute of Nuclear Engineering and Science, National Tsing Hua University, Hsinchu 300, Taiwan (China)], E-mail: spteng@ess.nthu.edu.tw

    2008-12-30

    Utilization of local Taiwan laterite (LTL) to remove aqueous cesium was investigated in this work under the conditions of various contact time, cesium (Cs) loading and temperature. Experimental results show that adsorption is instantaneous. Freundlich and Langmuir simulation results demonstrate that local Taiwan laterite has high affinity and sorption capacity for Cs at low temperatures, which may be attributed to enhanced desorption as temperature increased. Thermodynamic parameters including {delta}H, {delta}G and {delta}S were calculated and it is indicated that Cs adsorption on LTL is an exothermic, spontaneous and physical adsorption reaction. Moreover, the adsorbed Cs is distributed evenly on the LTL surface, which is confirmed by SEM/EDS mapping images. Furthermore, the absence of apparent shifting or broadening of the kaolinite signal in XRD patterns after Cs adsorption is an indication of the non-expanding characteristic of kaolinite structure.

  8. Synthesis of Activated Carbon Mesoporous from Coffee Waste and Its Application in Adsorption Zinc and Mercury Ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2012-01-01

    Full Text Available We obtain activated carbons with high portion of meso pores using coffee residues as precursor for the application of adsorption of large adsorbates. Because of its natural properties, the coffee residue exhibited a large pore size. In this work, the coffee residue were impregnated with ZnCl2 and KOH, and then carbonized under the nitrogen conditions and activated with CO2 respectively. Obtained activated carbons are used in the adsorption of ions Hg(II and Zn(II. These adsorbents are efficacious to remove these ions from aqueous solution, with monocomponent equilibrium adsorption capacities ranging from from 0.002 to 0.380 mmol∙g-1 for Hg on ACK3 and from 0.002 to 0.330 mmol∙g-1 for ACZ3. For Zn(II on ACK2 from 0.002 to 0.300 mmol∙g-1, and from 0.001 to 0.274 mmol∙g-1 for ACZ2.

  9. Phragmites karka as a Biosorbent for the Removal of Mercury Metal Ions from Aqueous Solution: Effect of Modification

    Directory of Open Access Journals (Sweden)

    Muhammad Hamid Raza

    2015-01-01

    Full Text Available Batch scale studies for the adsorption potential of novel biosorbent Phragmites karka (Trin, in its natural and treated forms, were performed for removal of mercury ions from aqueous solution. The study was carried out at different parameters to obtain optimum conditions of pH, biosorbent dose, agitation speed, time of contact, temperature, and initial metal ion concentration. To analyze the suitability of the process and maximum amount of metal uptake, Dubinin-Radushkevich (D-R model, Freundlich isotherm, and Langmuir isotherm were applied. The values of qmax for natural and treated biosorbents were found at 1.79 and 2.27 mg/g, respectively. The optimum values of contact time and agitation speed were found at 50 min and 150 rpm for natural biosorbent whereas 40 min and 100 rpm for treated biosorbent, respectively. The optimum biosorption capacities were observed at pH 4 and temperature 313 K for both natural P. karka and treated P. karka. RL values indicate that comparatively treated P. karka was more feasible for mercury adsorption compared to natural P. karka. Both pseudo-first-order and pseudo-second-order kinetic models were applied and it was found that data fit best to the pseudo-second-order kinetic model. Thermodynamic studies indicate that adsorption process was spontaneous, feasible, and endothermic.

  10. Removal of Cu(II Ions from Aqueous Solutions by Adsorption Onto Activated Carbon Derived From Olive Waste Cakes

    Directory of Open Access Journals (Sweden)

    Hesham G. Ibrahim

    2016-04-01

    Full Text Available This paper studied the ability of using local activated carbon (LAC derived from olive waste cakes as an adsorbent for the removal of Cu(II ions from aqueous solution by batch operation. Various operating parameters such as solution pH, adsorbent dosage, initial metal ions concentration, and equilibrium contact time have been studied. The results indicated that the adsorption of Cu(II increased with the increasing pH, and the optimum solution pH for the adsorption of Cu(II was found to be 5. The adsorption process increases with increasing dosage of LAC, also the amount of Cu(II removed changes with Cu(II initial concentration and contact time. Adsorption was rapid and occurred within 25 min. for Cu(II concentration range from 60 to 120 mg/l isothermally at 30±1 oC. Maximum adsorption occurs at Cu(II initial concentration lesser than 100 mg/l by using adsorbent dosage (1.2 g/l. The equilibrium adsorption data for Cu(II were fitted well with the Langmuir and Freundlich adsorption isotherm models. The maximum adsorption capacity of LAC was found to be 106.383 mg/g. So, the results indicated the suitability use of the activated carbon derived from olive waste cakes (LAC as low cost and natural material for reliable removal of Cu(II from water and wastewater effluents.

  11. Fluorimetric detection of Sn2 + ion in aqueous medium using Salicylaldehyde based nanoparticles and application to natural samples analysis

    Science.gov (United States)

    Patil, Kishor S.; Mahajan, Prasad G.; Patil, Shivajirao R.

    2017-01-01

    The fluorescent 2-[(E)-(2-phenylhydrazinylidene)methyl]phenol nanoparticles (PHPNPs) were prepared by a simple reprecipitation method. The prepared PHPNPs examined by Dynamic Light Scattering show narrower particle size distribution having an average particle size of 93.3 nm. The Scanning Electron Microphotograph shows distinct spherical shaped morphology of nanoparticles. The blue shift in UV-absorption and fluorescence spectra of PHPNPs with respect to corresponding spectra of PHP in acetone solution indicates H- aggregates and Aggregation Induced Enhanced Emission (AIEE) for nanoparticles. The nanoparticles show selective tendency towards the recognition of Sn2 + ions by enhancing the fluorescence intensity preference to Cu2 +, Fe3 +, Fe2 +, Ni2 +, NH4+, Ca2 +, Pb2 +, Hg2 + and Zn2 + ions, which actually seem to quench the fluorescence of nanoparticles. The studies on Langmuir adsorption plot, fluorescence lifetime of PHPNPs, DLS-Zeta sizer, UV-visible and fluorescence titration with and without Sn2 + helped to propose a suitable mechanism of fluorescence enhancement of nanoparticles by Sn2 + and their binding ability during complexation. The fluorescence enhancement effect of PHPNPs induced by Sn2 + is further used to develop an analytical method for detection of Sn2 + from aqueous medium in environmental samples.

  12. Removal of lead ions from aqueous solution by the dried aquatic plant, Lemna perpusilla Torr

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yankui, E-mail: tangyankui101@163.com [College of Environment, Guangxi University, Nanning 530004 (China); Chen, Ling; Wei, Xingren; Yao, Qiuyan; Li, Ting [College of Environment, Guangxi University, Nanning 530004 (China)

    2013-01-15

    Highlights: ► We found dried Lemna perpusilla Torr. acted as a respective adsorbent for Pb removal. ► We found the adsorption isotherm followed Langmuir model. ► We found the adsorption kinetics followed the pseudo-second-order model. ► We found Pb(II) adsorption on the biomass could be physical and chemical. -- Abstract: The aquatic plant, Lemna perpusilla Torr. strain, was dried, pulverized and used for Pb(II) removal from aqueous solution. Batch experiments were conducted to investigate the effects of pH, contact time, initial metal concentration and temperature on Pb(II) adsorption. A dose of 4 g L{sup −1} of dried L. perpusilla in a solution with an initial pH of 4.6, an initial Pb(II) concentration of 50 mg L{sup −1} and a contact time of 210 min resulted in the maximum Pb(II) removal efficiency (above 95%). The equilibrium adsorption capacities increased with increasing initial Pb(II) concentration. The adsorption isotherm was better described by a Langmuir model rather than a Freundlich model. Further, the adsorption kinetics followed a pseudo-second-order model. An FTIR examination revealed changes between the natural and Pb(II)-loaded plant material. Scanning electron micrograph (SEM) also revealed changes in the surface morphology of the biomass as a result of lead adsorption. Based on these results, it can be concluded that the dried L. perpusilla is effective in removing lead from aqueous solution and merits consideration for scaled-up trials.

  13. Advanced ion beam calorimetry for the test facility ELISE

    Science.gov (United States)

    Nocentini, R.; Bonomo, F.; Pimazzoni, A.; Fantz, U.; Franzen, P.; Fröschle, M.; Heinemann, B.; Pasqualotto, R.; Riedl, R.; Ruf, B.; Wünderlich, D.

    2015-04-01

    The negative ion source test facility ELISE (Extraction from a Large Ion Source Experiment) is in operation since beginning of 2013 at the Max-Planck-Institut für Plasmaphysik (IPP) in Garching bei München. The large radio frequency driven ion source of ELISE is about 1×1 m2 in size (1/2 the ITER source) and can produce a plasma for up to 1 h. Negative ions can be extracted and accelerated by an ITER-like extraction system made of 3 grids with an area of 0.1 m2, for 10 s every 3 minutes. A total accelerating voltage of up to 60 kV is available, i.e. a maximum ion beam power of about 1.2 MW can be produced. ELISE is equipped with several beam diagnostic tools for the evaluation of the beam characteristics. In order to evaluate the beam properties with a high level of detail, a sophisticated diagnostic calorimeter has been installed in the test facility at the end of 2013, starting operation in January 2014. The diagnostic calorimeter is split into 4 copper plates with separate water calorimetry for each of the plates. Each calorimeter plate is made of 15×15 copper blocks, which act as many separate inertial calorimeters and are attached to a copper plate with an embedded cooling circuit. The block geometry and the connection with the cooling plate are optimized to accurately measure the time-averaged power of the 10 s ion beam. The surface of the blocks is covered with a black coating that allows infrared (IR) thermography which provides a 2D profile of the beam power density. In order to calibrate the IR thermography, 48 thermocouples are installed in as many blocks, arranged in two vertical and two horizontal rows. The paper describes the beam calorimetry in ELISE, including the methods used for the IR thermography, the water calorimetry and the analytical methods for beam profile evaluation. It is shown how the maximum beam inhomogeneity amounts to 13% in average. The beam divergence derived by IR thermography ranges between 1° and 4° and correlates

  14. A novel Schiff-base as a Cu(II) ion fluorescent sensor in aqueous solution.

    Science.gov (United States)

    Gündüz, Z Yurtman; Gündüz, C; Özpınar, C; Urucu, O Aydın

    2015-02-05

    A new fluorescent Cu(II) sensor (L) obtained from the Schiff base of 5,5'-methylene-bis-salicylaldehyde with amidol (2,4-diaminophenol) was synthesized and characterized by FT-IR, MS, (1)H NMR, (13)C NMR techniques. In the presence of pH 6.5 (KHPO4-Na2HPO4) buffer solutions, copper reacted with L to form a stable 2:1 complex. Fluorescence spectroscopic study showed that Schiff base is highly sensitive towards Cu(II) over other metal ions (K(+), Na(+), Al(3+), Ni(2+), Co(2+), Fe(3+), Zn(2+), Pb(2+)) in DMSO/H2O (30%, v/v). The sensor L was successfully applied to the determination of copper in standard reference material. The structural properties and molecular orbitals of the complex formed between L and Cu(2+) ions were also investigated using quantum chemical computations.

  15. Application of porphyrin modified SBA-15 in adsorption of lead ions from aqueous media

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Asgari

    2015-09-01

    Full Text Available Mesoporous silica SBA-15 was synthesized using P123 as surfactant and functionalized with (3-chloropropyl triethoxysilane. For the first time, the composite of THPP-SBA-15 was prepared using incorporation of tetrakis(4-hydroxyphenylporphyrin in functionalized SBA-15. The materials were characterized by BET, SEM, XRD, FT-IR, DRS, and UV–Vis spectroscopy techniques. The synthesized composite was employed as adsorbent of heavy metal ion (Pb2+ from water at room temperature. Results indicated that the presence of porphyrin in silica significantly increased heavy metal ion adsorption. The maximum adsorption capacity (qmax of THPP-SBA-15 for Pb2+ was found to be 134 mg/g.

  16. Sorption of Uranium Ions from Their Aqueous Solution by Resins Containing Nanomagnetite Particles

    Directory of Open Access Journals (Sweden)

    Mahmoud O. Abd El-Magied

    2016-01-01

    Full Text Available Magnetic amine resins composed of nanomagnetite (Fe3O4 core and glycidyl methacrylate (GMA/N,N′-methylenebisacrylamide (MBA shell were prepared by suspension polymerization of glycidyl methacrylate with N,N′-methylenebisacrylamide in the presence of nanomagnetite particles and immobilized with different amine ligands. These resins showed good magnetic properties and could be easily retrieved from their suspensions using an external magnetic field. Adsorption behaviors of uranium ions on the prepared resins were studied. Maximum sorption capacities of uranium ions on R-1 and R-2 were found to be 92 and 158 mg/g. Uranium was extracted successfully from three granite samples collected from Gabal Gattar pluton, North Eastern Desert, Egypt. The studied resins showed good durability and regeneration using HNO3.

  17. Aspartate buffer and divalent metal ions affect oxytocin in aqueous solution and protect it from degradation

    DEFF Research Database (Denmark)

    Avanti, Christina; Oktaviani, Nur Alia; Hinrichs, Wouther L.J.

    2013-01-01

    is improved by the addition of divalent metal ions (unpublished results). The stabilizing effect of Zn2+ was by far superior compared to that of Mg2+. In addition, it was found that stabilization correlated well with the ability of the divalent metal ions to interact with oxytocin in aspartate buffer...... favorable. These interactions may explain the protection of the disulfide bridge against intermolecular reactions that lead to dimerization.Mg or Zn, using 2D NOESY, TOCSY, H-C HSQC and H- N HSQC NMR spectroscopy. Almost all H, C and N resonances of oxytocin could be assigned using HSQC spectroscopy...... that the carboxylate group of aspartate neutralizes the positive charge of the N-terminus of Cys, allowing the interactions with Zn to become more favorable. These interactions may explain the protection of the disulfide bridge against intermolecular reactions that lead to dimerization....

  18. Modified granular activated carbon: A carrier for the recovery of nickel ions from aqueous wastes

    Energy Technology Data Exchange (ETDEWEB)

    Satapathy, D.; Natarajan, G.S.; Sen, R. [Central Fuel Research Inst., Nagpur (India)

    2004-07-01

    Granular Activated Carbon (GAC) is widely used for the removal and recovery of toxic pollutants including metals because of its low cost and high affinity towards the scavenging of metal ions. Activated carbon derived from bituminous coal is preferred for wastewater treatment due to its considerable hardness, a characteristic needed to keep down handling losses during re-activation. Commercial grade bituminous coal based carbon, viz. Filtrasorb (F-400), was used in the present work. The scavenging of precious metals such as nickel onto GAC was studied and a possible attempt made to recover the adsorbed Ni{sup 2+} ions through the use of some suitable leaching processes. As part of the study, the role of complexing agents on the surface of the carbon was also investigated. The use of organic complexing agents such as oxine and 2-methyloxine in the recovery process was found to be promising. In addition, the surface of the carbon was modified with suitable oxidising agents that proved to be more effective than chelating agents. Several attempts were made to optimise the recovery of metal ions by carrying out experiments with oxidising agents in order to obtain maximum recovery from the minimum quantity of carbon. Experiments with nitric acid indicated that not only was the carbon surface modified but such modification also helped in carbon regeneration.

  19. Testing the cleaning effectiveness of new ecological aqueous dispersions applied on old icons

    Science.gov (United States)

    Vasilache, Viorica; Sandu, Irina Crina Anca; Pruteanu, Silvea; Caldeira, Ana Teresa; Simionescu, Atena Elena; Sandu, Ion

    2016-03-01

    Adherent deposits are very aggressive towards ancient heritage paintings since they affect the varnish and the painting's layers, sometimes reaching the preparative layers. The biggest problem to the restorer is their removal without affecting the patina, the transparent varnish (well preserved) and fine colour glazes made during painting. Therefore, their removal requires preliminary cleaning tests that allow the optimization of the cleaning system composition that is going to be used. The study was focused on organic natural systems, as colourless supernatants, some of them used during ages, but insufficiently studied. The paper presents an evaluation of the effectiveness of cleaning varnished icons of the nineteenth century, with complex conservation cases using supernatants derived from aqueous dispersions extracted from vegetables and dry indigenous herbal infusions. Best results, after six consecutive cleaning steps, on tempera old icon was obtained for a mixture made of mature white onion juice + extract of Soapwort flowers + corn silk tea + acacia tea. As a best result after just one cleaning step was obtained for a quaternary mixture composed from mature white onion juice + mature carrot juice + corn silk tea + aqueous extract of Soapwort flowers.

  20. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO₂ nanoparticles from aqueous media.

    Science.gov (United States)

    Shaker, Medhat A; Yakout, Amr A

    2016-02-05

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51±3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, (1)H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r(2)) and non-linear Chi-square (χ(2)) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

  1. ADSORPTION OF Ni(II IONS FROM AQUEOUS SOLUTIONS ONTO MAGNETIC POLY( DIVINYLBENZENE-CO-VINYLIMIDAZOLE MICROBEADS: PHYSICOCHEMICAL STUDIES

    Directory of Open Access Journals (Sweden)

    Ali KARA

    2012-06-01

    Full Text Available A modified suspension polymerization was used for the preparation of the mesoporous magnetic-poly(divinylbenzene-co-vinylimidazole (m-poly(DVB-VIM microbeads in size 53-212 μm of average diameter. The specific surface area and the DVB/VIM mol ratio of the microsphereswere determined as 29.47 m2/g and 1:4 mol/mol with Fe3O4, respectively. The physicochemical studies of adsorption of Ni(II ions from aqueous solutions such as pH, initial concentration, amountof mesoporous m-poly(DVB-VIM microbeads, contact time, and temperature onto the m-poly(DVBVIM microspheres were carried out. The maximum adsorption capacities of the m-poly(DVB-VIMmicrospheres towards Ni(II ions were determined as 13.51, 20.14, 21.00 and 23.62 mg/g at 277 K, 298 K, 318 K, and 338 K, respectively. The dynamic and equilibrium adsorption behaviours of the system were adequately described by the pseudo-second-order kinetic and the Langmuir isotherm models, respectively. Various thermodynamic parameters, such as the Gibbs’ free energy change (ΔGo, the standard enthalpy change (ΔHo and the standard entropy change (ΔSo were also determined. Morever, after use in the adsorption, the m-poly(DVB-VIM microbeads with paramagnetic property was separated from the via the applied magnetic force. These results indicate that the material studied could be used as a purifier for the removal of Ni(II ions from water and wastewater under magnetic field.

  2. COMPETITIVE BIOSORPTION OF LEAD (II IONS FROM AQUEOUS SOLUTIONS ONTO TERMINALIA CATAPPA L. LEAVES AS A COST EFFECTIVE BIOSORBENT

    Directory of Open Access Journals (Sweden)

    Jagruti N. Jadav

    2015-03-01

    successfully used for the competitive biosorption studies of Pb(II ions from aqueous solutions and can be applied in waste water technology for remediation of heavy metal contamination.

  3. Durability of API class B cement pastes exposed to aqueous solutions containing chloride, sulphate and magnesium ions

    Directory of Open Access Journals (Sweden)

    Hernández, M. E.

    2008-12-01

    Full Text Available This paper discusses a durability study conducted on API class B cement, the type used in shallow oil wells, when exposed to aggressive formation water. Its resistance to the major ions, namely –SO4=, Mg+2 and Cl-–, is related both to its capacity to assimilate the aggressive action of each harmful agent and to the changes in the chemical reactivity of some of its components. The methodology used consisted in preparing and immersing cement specimens in neutral solutions containing variable concentrations of these ions to monitor the chemical reactions taking place. These solutions were analyzed and XRD studies were conducted for over a year to identify mineralogical variations. The purposes of the study were to determine the effects of joint ionic attack on this kind of cement and to monitor the variations in the calcium concentration in the aqueous solutions of Na2SO4, MgCl2 and NaCl in contact with API class B cement pastesEste trabajo se basa en el estudio de la durabilidad de un cemento API clase B, utilizado en pozos petrolíferos someros, frente a la agresividad de las aguas de formación a las que puede estar expuesto. Su eficacia frente a la exposición a los iones más importantes –SO4=, Mg+2 y Cl-– se relaciona con su capacidad de asimilar la acción agresiva de cada agente perjudicial, así como de las reacciones químicas que sufra por la reactividad de alguno de sus compuestos. La metodología aplicada supone la preparación de probetas de este cemento y su inmersión en disoluciones neutras, conteniendo los referidos iones a distintas concentraciones, para evaluar el desarrollo de las reacciones existentes en su seno. A tal fin se realizaron análisis de las disoluciones y estudios de DRX durante más de un año para conocer su evolución mineralógica. El objetivo del trabajo ha sido determinar los efectos resultantes de los ataques conjuntos de los citados iones al referido cemento; así como la observación de las

  4. Thermal Development Test of the NEXT PM1 Ion Engine

    Science.gov (United States)

    Anderson, John R.; Snyder, John S.; VanNoord, Jonathan L.; Soulas, George C.

    2010-01-01

    NASA's Evolutionary Xenon Thruster (NEXT) is a next-generation high-power ion propulsion system under development by NASA as a part of the In-Space Propulsion Technology Program. NEXT is designed for use on robotic exploration missions of the solar system using solar electric power. Potential mission destinations that could benefit from a NEXT Solar Electric Propulsion (SEP) system include inner planets, small bodies, and outer planets and their moons. This range of robotic exploration missions generally calls for ion propulsion systems with deep throttling capability and system input power ranging from 0.6 to 25 kW, as referenced to solar array output at 1 Astronomical Unit (AU). Thermal development testing of the NEXT prototype model 1 (PM1) was conducted at JPL to assist in developing and validating a thruster thermal model and assessing the thermal design margins. NEXT PM1 performance prior to, during and subsequent to thermal testing are presented. Test results are compared to the predicted hot and cold environments expected missions and the functionality of the thruster for these missions is discussed.

  5. EDXRF Analysis of Some Fungal Species for the Uptake Capacity of 28Ni, 48Cd, and 82Pb Metal Ions From Aqueous Solution

    Directory of Open Access Journals (Sweden)

    SUNIL KUMAR

    2016-02-01

    Full Text Available In this paper, Energy Dispersive X-ray Fluorescence (EDXRF analysis of eight fungi species, namely, Aspergillus niger, Aspergillus terreus, Trichoderma longibrachiatum, Trichoderma fasciculatum, Penicillin Janthinellum, Aspergillus awamori, Phanerochaete chrysosporium, and Rhizopus arrhizus for the uptake capacity of 28Ni, 48Cd, and 82Pb metals ions from aqueous solution have been reported. Fungal samples having superior ion removal capacity through bioaccumulation and biosorption were obtained from sites contaminated with heavy metals. The detection limit in EDXRF set up was improved considerably using selective absorbers in the path of incident photons from the X-ray tube to reduce the background in the desired energy region. It has been observed that all fungi species under present study have greater affinity for 82Pb ions as compared to 28Ni and 48Cd metal ions. The Trichoderma longibrachiatum and Trichoderma fasciculatum fungi species were identified to be more efficient for removal of heavy metal ions from waste water. The measured uptake capacity of Trichoderma longibrachiatum for 28Ni, 48Cd, and 82Pb ions from aqueous solution is 0.52 mg/g, 0.97 mg/g, and 6.4 mg/g, respectively, and for Trichoderma fasciculatum it is 0.43 mg/g, 0.79 mg/g, and 3.5 mg/g, respectively. This indicated the potential of these identified fungi species as biosorbent for removal of high metal ions from waste water and industrial effluents.

  6. Sequestering Potential of Peach Nut Shells as an Efficient Sorbent for Sequestering Some Toxic Metal Ions from Aqueous Waste: A Kinetic and Thermodynamic Study

    Directory of Open Access Journals (Sweden)

    Muhammad Ashraf Shaheen

    2016-06-01

    Full Text Available The peach nut shells potential as a low cost biosorbent for separation of certain metal ions from aqueous media was investigated. The effects of different parameters such as pH, shaking speed, initial metal ions concentration and their contact time with adsorbent on sorption efficiency of biosorbent was investigated to optimize the parameters for maximum sorption. The FT–IR spectroscopy and TGA were used to characterize the biosorbent. A significant increase in sorption was noted with rise in pH of metal ions solution and maximum sorption was observed at pH 6. The isothermal data was fitted to Langmuir, Dubinin–Radushkevich (D–R, Freundlich isotherms and equilibrium process was best fitted to Langmuir isotherm. The removal efficiency of chemically activated samples was found to be ~35 to 45% greater than raw sample. The results showed that peach nut shell was an effective biosorbent for the remediation of the contaminated water with lead (II, Nickle (II and Chromium (III ions. Being low cost material, PNS has a potential to be exploited in waste water treatment technologies. This study shows that activated PNS exhibited appreciable sorption for Pb, Cr and Ni metals ions (97%, 95% and 94% respectively from aqueous solution even at very low concentration of sorbent. The chemical and thermal activation of peach nut shells enhances the removal efficiency for all the metal ions and from the reported data; it was found that the adsorption ability of Pb ions was greater than nickel and chromium.

  7. Kinetic and thermodynamic studies on the adsorption of U(VI) ions on densely crosslinked poly(methacrylic acid) from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Oezeroglu, C.; Keceli, G. [Istanbul Univ., Dept. of Chemistry, Avcilar Istanbul (Turkey)

    2009-07-01

    In this study, densely crosslinked poly(methacrylie acid) was used to adsorb uranium(VI) ions from aqueous solution. For this purpose, the crosslinked copolymer of ethylene glycol dimethacrylate (EGDM) and methacrylic acid (MA) containing 25% (w/w) methacrylic acid (MA) was synthesized by using dibenzoyl peroxide-N,N-dimethylaniline (BPO-DMA) initiator system at room temperature. The adsorption of uranium(Vl) ions on the copolymer sample (0.02 g copolymer/5 mL solution of U(VI) ions) was carried out in a batch reactor. The parameters which effect the uranium adsorption process, such as, contact time. pH of solution, initial uranium(VI) concentration and temperature were investigated. It was observed that an increase in these parameters enhanced the removal of U(VI) ions from aqueous solution. The adsorption data were modelled by the Freundlich. Langmuir and Dubinin-Radushkevich (D-R) isotherms. The adsorption capacity of the crosslinked copolymer and free energy change were calculated by using D-R isotherms. Thermodynamic parameters ({delta}H , {delta}S and {delta}G ) were determined for the adsorption of U(VI) ions from aqueous solutions by the crosslinked copolymer bearing methacrylic acid functional groups. Experimental adsorption data were analyzed using sorption kinetic models of the pseudo-first order and pseudo-second order kinetic models. It was observed that pseudo-second order kinetic model provided a high goodness of fit with experimental data for the adsorption of U(VI) ions on the crosslinked copolymer bearing methacrylic acid functional groups. The densely crosslinked poly(methacrylic acid) might be of interest in large scale uranium removals from aqueous solution, since it had high uranyl sorption capacities ranging from 0.16 to 2.37 mmol/g copolymer at pH 2.7 (293 K). (orig.)

  8. Use of Composite Sorbents for the Removal of Copper (II ions from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Rebecca Oyedoyin Adeeyo

    2015-01-01

    Full Text Available Composite adsorbents are synthesized from two or more materials with different chemical and physical properties in order to increase their selectivity and the reusability. Researchers have developed and applied several novel composite materials for enhancing the removal of heavy metal. In this review, extensive list of composites developed via advanced technologies with specified characteristics for the removal of Cu (II ion are discussed. Emphases on their adsorption capacities, reusability, desorption and regeneration with improved mechanical strengths are presented. Conclusively, prospects and other challenges to be checked and addressed in future are outlined.

  9. Removal of heavy metal ions from aqueous solution using red loess as an adsorbent.

    Science.gov (United States)

    Xing, Shengtao; Zhao, Meiqing; Ma, Zichuan

    2011-01-01

    The adsorption behaviors of heavy metals onto novel low-cost adsorbent, red loess, were investigated. Red loess was characterized by X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectra. The results indicated that red loess mainly consisted of silicate, ferric and aluminum oxides. Solution pH, adsorbent dosage, initial metal concentration, contact time and temperature significantly influenced the efficiency of heavy metals removal. The adsorption reached equilibrium at 4 hr, and the experimental equilibrium data were fitted to Langmuir monolayer adsorption model. The adsorption of Cu(II) and Zn(II) onto red loess was endothermic, while the adsorption of Pb(II) was exothermic. The maximum adsorption capacities of red loess for Pb(II), Cu(II) and Zn(II) were estimated to be 113.6, 34.2 and 17.5 mg/g, respectively at 25 degrees C and pH 6. The maximum removal efficiencies were 100% for Pb(II) at pH 7, 100% for Cu(II) at pH 8, and 80% for Zn(II) at pH 8. The used adsorbents were readily regenerated using dilute HCl solution, indicating that red loess has a high reusability. All the above results demonstrated that red loess could be used as a possible alternative low-cost adsorbent for the removal of heavy metals from aqueous solution.

  10. Kinetics of ion flotation of Co(II)-EDTA complexes from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, Mohamed A. [Atomic Energy Authority, Cairo (Egypt). Egypt Second Research Reactor; Rashad, Ghada M.; Mahmoud, Mamdoh R. [Atomic Energy Authority, Cairo (Egypt). Nuclear Chemistry Dept.

    2015-07-01

    The flotation kinetics of Co(II)-EDTA complexes from aqueous solutions using cetylpyridinium chloride (CPyCl) is studied and discussed in the present work. The effects of many variables on the ultimate recovery and the flotation rate are investigated. The data obtained from solutions of different pH values showed that Co(II)-EDTA complexes are successfully floated at pH 7.8. While at pH 3.4 and 11.2, both the ultimate recovery and the flotation rate are dependent on the concentration of CPyCl. Flotation of Co(II)-EDTA at different air flow rates, CPyCl concentrations and ionic strength showed that the ultimate recovery and the flotation rate are markedly affected. The other parameters (cobalt, EDTA and ethanol concentrations) had no effect on the ultimate recovery, while significantly affected the flotation rate. At the optimum conditions (Co(II):EDTA = 1:1; CPyCl:Co(II) = 4:1; pH7.8; G = 25 cm{sup 3}/min), removals more than 99% are achieved for radiocobalt. The classical first-order and the second-order kinetic models are used throughout the work to analyze the experimental kinetic data. At all the studied parameters, the kinetic data of Co(II)-EDTA complexes are better fitted to the classical first-order model.

  11. Application of annealed red mud to Mn(2+) ion adsorption from aqueous solution.

    Science.gov (United States)

    Chen, Hongliang; Zheng, Juan; Zhang, Zhongqiong; Long, Qian; Zhang, Qiuyun

    2016-01-01

    Physicochemical characteristics and Mn(2+) adsorption of annealed red mud were investigated in this study. The annealing temperature (105-900 °C) changed the mineralogical components and the point of zero charge of red mud. By comparison, annealed red mud at 700 °C (ARM700) had a better adsorption effect than other annealed samples, associated with the activated components of available Fe2O3, Al2O3, SiO2 and Na5Al3(SiO4)3CO3 (natrodavyne). The removal efficiency of Mn(2+) by ARM700 was dependent on initial pH, contact time, and initial Mn(2+) concentration of aqueous solution and was ∼56.5% with initial Mn(2+) concentration 385 mg/L at initial pH > 5. The kinetics process was predicted better by the pseudo-second-order model. The Langmuir isotherm displayed a better fitting model than the Freundlich isotherm and the Mn(2+) maximum adsorption capacity of ARM700 was 88.3 mg/g. The competing effects of Cu(2+) and Zn(2+) on Mn(2+) removal were most obvious. There was efficient Mn(2+) removal at the application of ARM700 to the leachate of electrolytic manganese residue.

  12. Removal of heavy metal ions from aqueous solution using red loess as an adsorbent

    Institute of Scientific and Technical Information of China (English)

    Shengtao Xing; Meiqing Zhao; Zichuan Ma

    2011-01-01

    The adsorption behaviors of heavy metals onto novel low-cost adsorbent,red loess,were investigated.Red loess was characterized by X-ray diffraction,scanning electron microscopy and Fourier transform infrared spectra.The results indicated that red loess mainly consisted of silicate,ferric and aluminum oxides.Solution pH,adsorbent dosage,initial metal concentration,contact time and temperature significantly influenced the efficiency of heavy metals removal.The adsorption reached equilibrium at 4 hr,and the experimental equilibrium data were fitted to Langmuir monolayer adsorption model.The adsorption of Cu(Ⅱ) and Zn(Ⅱ) onto red loess was endothermic,while the adsorption of Pb(Ⅱ) was exothermic.The maximum adsorption capacities of red loess for Pb(Ⅱ),Cu(Ⅱ)and Zn(Ⅱ) were estimated to be 113.6,34.2 and 17.5 mg/g,respectively at 25°C and pH 6.The maximum removal efficiencies were 100% for Pb(Ⅱ) at pH 7,100% for Cu(Ⅱ) at pH 8,and 80% for Zn(Ⅱ) at pH 8.The used adsorbents were readily regenerated using dilute HCI solution,indicating that red loess has a high reusability.All the above results demonstrated that red loess could be used as a possible alternative low-cost adsorbent for the removal of heavy metals from aqueous solution.

  13. Chemically and biologically modified activated carbon sorbents for the removal of lead ions from aqueous media.

    Science.gov (United States)

    Mahmoud, Mohamed E; Abdel-Fattah, Tarek M; Osman, Maher M; Ahmed, Somia B

    2012-01-01

    A method is described for hybridization of the adsorption and biosorption characteristics of chemically treated commercial activated carbon and baker's yeast, respectively, for the formation of environmental friendly multifunctional sorbents. Activated carbon was loaded with baker's yeast after acid-base treatment. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) Spectroscopy were used to characterize these sorbents. Moreover, the sorption capabilities for lead (II) ions were evaluated. A value of 90 μmol g(-1) was identified as the maximum sorption capacity of activated carbon. Acid-base treatment of activated carbon was found to double the sorption capacity (140-180 μmol g(-1)). Immobilization of baker's yeast on the surface of activated carbon sorbents was found to further improve the sorption capacity efficiency of lead to 360, 510 and 560 μmol g(-1), respectively. Several important factors such as pH, contact time, sorbent dose, lead concentration and interfering ions were examined. Lead sorption process was studied and evaluated by several adsorption isotherms and found to follow the Langmuir and BET models. The potential applications of various chemically and biologically modified sorbents and biosorbents for removal of lead from real water matrices were also investigated via multistage micro-column technique and the results referred to excellent recovery values of lead (95.0-99.0 ± 3.0-5.0 %).

  14. Removal of cesium ion in aqueous solution using immobilized sericite beads

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Choong [Kwandong University, Gangneung (Korea, Republic of); Kim, Jong-Oh [Hanyang University, Seoul (Korea, Republic of); Lee, Seung-Mok [Gangneung-Wonju National University, Gangneung (Korea, Republic of)

    2014-07-15

    To apply sericite effectively in the adsorption process, it was immobilized by entrapment method using sodium alginate. Since the immobilized sericite beads have excellent mechanical strength and swelling characteristics, channeling of flow and the increase of pressure drop were not observed through column operations. In addition, it was also stable under pH 10 and 45 .deg. C of cesium solution. The maximum adsorption capacity and Langmuir adsorption constant was 1.430mg/g and 2.329 L/mg, respectively, at initial pH 5 of cesium solution in batch type and the Langmuir model with higher correlation coefficient of 0.997 fits experimental data better than Freundlich model. The breakthrough point emerged around 15 (1.0 mL/min) and 20 bed volumes (0.5 mL/min), and the cesium ions bound to the immobilized sericite beads were readily released and quantitatively recovered by a few bed volumes of 1.0M of HNO{sub 3} solution. Furthermore, bed volumes of cesium ions for firstly reused sericite beads can be still maintained as 18, which shows good regeneration ability.

  15. Ion Exchange Testing with SRF Resin FY 2012

    Energy Technology Data Exchange (ETDEWEB)

    Russell, Renee L.; Rinehart, Donald E.; Peterson, Reid A.

    2014-07-02

    Ion exchange using spherical resorcinol-formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection (DOE-ORP) for use in the Pretreatment Facility (PTF) of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in at-tank deployment. Numerous studies have shown SRF resin to be effective for removing 137Cs from a wide variety of actual and simulated tank waste supernatants (Adamson et al. 2006; Blanchard et al. 2008; Burgeson et al. 2004; Duignan and Nash 2009; Fiskum et al. 2006a; Fiskum et al. 2006b; Fiskum et al. 2006c; Fiskum et al. 2007; Hassan and Adu-Wusu 2003; King et al. 2004; Nash et al. 2006). Prior work at the Pacific Northwest National Laboratory (PNNL) has focused primarily on the loading behavior for 4 to 6 M Na solutions at 25 to 45°C. Recent proposed changes to the WTP ion exchange process baseline indicate that loading may include a broader range of sodium molarities (0.1 to 8 M) and higher temperatures (50°C) to alleviate post-filtration precipitation issues. This report discusses ion exchange loading kinetics testing activities performed in accordance with Test Plan TP-WTPSP-002, Rev. 3.01, which was prepared and approved in response to the Test Specification 24590-PTF-TSP-RT-09-002, Rev. 0 (Lehrman 2010) and Test Exception 24590-PTF-TEF-RT-11-00003, Rev. 0 (Meehan 2011). This testing focused on column tests evaluating the impact of elevated temperature on resin degradation over an extended period of time and batch contacts evaluating the impact on Cs loading over a broad range of sodium concentrations (0.1 to 5 M). These changes may be required to alleviate post-filtration precipitation issues and broaden the data range of SRF resin loading under the conditions expected with the new equipment and process changes.

  16. Characterization of the properties of stationary phases for liquid chromatography in aqueous mobile phases using aromatic sulphonic acids as the test compounds.

    Science.gov (United States)

    Jandera, P; Bocian, S; Molíková, M; Buszewski, B

    2009-01-09

    We investigated the effects of the concentration of naphthalene sulphonic acids (NSAs) as anionic test compounds in the injected sample and of the salt additives to the mobile phase on ion-exclusion. The retention behaviour of NSAs sensitively reflects even minor changes in the ionic and hydrophobic interactions and can be useful for predicting the effects of the stationary phases in reversed-phase chromatography of polar and ionic compounds, both small ones and biopolymers, e.g., oligonucleotides. We studied chromatographic properties of several stationary phases intended for separations in aqueous mobile phases: a C18 column end-capped with polar hydrophilic groups, a densely bonded C8 column doubly end-capped with short alkyl groups, a short alkyl stationary phase designed to keep full pore accessibility in highly-aqueous mobile phases and a Bidentate column with "bridged" C18 groups attached to the silica hydride support. The chemistry and pore structure of various types of column packing materials and of the salt additives to the mobile phase affect the proportion of the pore volume non-accessible to anions due to ion-exclusion and consequently the peak asymmetry and hydrophobic selectivity in reversed-phase chromatography of organic acids. We also addressed the problems connected with the determination of column hold-up volume in aqueous mobile phases. The accessibility of the stationary phase for anionic compounds in contact with the sample zone is affected by ion-exclusion due to repulsive interactions with the negatively charged surface in the pores of the stationary phase. The accessible part of the stationary phase increases and consequently the migration velocity along the column decreases with increasing concentration of the sample in the zone moving along the column. Because of a limited access to the stationary phase, its capacity can be easily overloaded. The combination of the column overload and ion-exclusion effects may result in fronting or

  17. Equilibrium, thermodynamic and kinetic studies for the biosorption of aqueous lead(II), cadmium(II) and nickel(II) ions on Spirulina platensis

    Energy Technology Data Exchange (ETDEWEB)

    Seker, Ayseguel [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: aysegulseker@iyte.edu.tr; Shahwan, Talal [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: talalshahwan@iyte.edu.tr; Eroglu, Ahmet E. [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: ahmeteroglu@iyte.edu.tr; Yilmaz, Sinan [Department of Chemistry, Izmir Institute of Technology, Urla 35430, Izmir (Turkey)], E-mail: sinanyilmaz@iyte.edu.tr; Demirel, Zeliha [Department of Biology, Ege University, Bornova 35100, Izmir (Turkey)], E-mail: zelihademirel@gmail.com; Dalay, Meltem Conk [Department of Bioengineering, Ege University, Bornova 35100, Izmir (Turkey)], E-mail: meltemconkdalay@gmail.com

    2008-06-15

    The biosorption of lead(II), cadmium(II) and nickel(II) ions from aqueous solution by Spirulina platensis was studied as a function of time, concentration, temperature, repetitive reactivity, and ionic competition. The kinetic results obeyed well the pseudo second-order model. Freundlich, Dubinin Radushkevich and Temkin isotherm models were applied in describing the equilibrium partition of the ions. Freundlich isotherm was applied to describe the design of a single-stage batch sorption system. According to the thermodynamic parameters such as {delta}G{sup o}, {delta}H{sup o}and {delta}S{sup o} calculated, the sorption process was endothermic and largely driven towards the products. Sorption activities in a three metal ion system were studied which indicated that there is a relative selectivity of the biosorbent towards Pb{sup 2+} ions. The measurements of the repetitive reusability of S. platensis indicated a large capacity towards the three metal ions.

  18. Thermodynamics of the formation of complexes of copper(II) ions and glycylglycine in aqueous solutions at 298 K according to calorimetry data

    Science.gov (United States)

    Kochergina, L. A.; Emel'yanov, A. V.

    2015-04-01

    Heat effects of the interaction between glycylglycine and copper(II) nitrate solutions are measured by direct calorimetry at a [metal] : [ligand] ratio of 1 : 5 and at different pH values of the solution. The measurements are made at a temperature of 298.15 K and ionic strengths of 0.25, 0.50, and 0.75. KNO3 is used as a background electrolyte. The thermodynamic characteristics of complex formation by the peptide and copper(II) ions in aqueous solutions are determined. Standard enthalpies of the formation of complex particles in aqueous solutions are calculated.

  19. High-resolution Measurement of Contact Ion-pair Structures in Aqueous RbCl Solutions from the Simultaneous Corefinement of their Rb and Cl K-edge XAFS and XRD Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Van-Thai; Fulton, John L.

    2016-06-21

    In concentrated solutions of aqueous RbCl, all of the Rb+ and Cl- ions exist as contact ion pairs. This full structural assessment is derived from the refinement of three independent experimental measurements: the Rb and Cl K-edge x-ray absorption fine structure (XAFS) and the x-ray diffraction spectra (XRD). This simultaneous refinement of the XAFS and XRD data provides high accuracy since each method probes the structure of different local regions about the ions with high sensitivity. At high RbCl concentration (6 m (mol/kg )) the solution is dominated by Rb+ - Cl- contact ion pairs yielding an average of 1.5 pairs at an Rb-Cl distance of 3.24 Å. Upon formation of these ion pairs, approximately 1.1 waters molecules are displaced from the Rb+ and 1.4 water molecules from Cl-. The hydration shells about both the cation and anion are also determined. These results greatly improve the understanding of monovalent ions and provide a basis for testing the Rb+-Cl- interaction potentials used in molecular dynamics (MD) simulation. This research was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences.

  20. Ion Exchange Column Tests Supporting Technetium Removal Resin Maturation

    Energy Technology Data Exchange (ETDEWEB)

    Nash, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); McCabe, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hamm, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Smith, F. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Morse, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2013-12-20

    The primary treatment of the tank waste at the DOE Hanford site will be done in the Waste Treatment and Immobilization Plant, currently under construction. The baseline plan for this facility is to treat the waste, splitting it into High Level Waste (HLW) and Low Activity Waste (LAW). Both waste streams are then separately vitrified as glass and sealed in canisters. The LAW glass will be disposed on site. There are currently no plans to treat the waste to remove technetium, so its disposition path is the LAW glass. Due to the soluble properties of pertechnetate and long half-life of 99Tc, effective management of 99Tc is important. Options are being explored to immobilize the supplemental LAW portion of the tank waste, as well as to examine the volatility of 99Tc during the vitrification process. Removal of 99Tc, followed by off-site disposal has potential to reduce treatment and disposal costs. A conceptual flow sheets for supplemental LAW treatment and disposal that could benefit from technetium removal will specifically examine removing 99Tc from the LAW feed stream to supplemental immobilization. SuperLig® 639 is an elutable ion exchange resin. In the tank waste, 99Tc is predominantly found in the tank supernate as pertechnetate (TcO4-). Perrhenate (ReO4-) has been shown to be a good non-radioactive surrogate for pertechnetate in laboratory testing for this ion exchange resin. This report contains results of experimental ion exchange distribution coefficient and column resin maturation kinetics testing using the resin SuperLig® 639a to selectively remove perrhenate from simulated LAW. This revision includes results from testing to determine effective resin operating temperature range. Loading tests were performed at 45°C, and the computer modeling was updated to include the temperature effects. Equilibrium contact testing indicated that this batch of

  1. Sonochemical degradation of textile dyes in aqueous solution using sulphate radicals activated by immobilized cobalt ions.

    Science.gov (United States)

    Gayathri, P; Praveena Juliya Dorathi, R; Palanivelu, K

    2010-03-01

    Decolorisation of dye solutions by cobalt activated persulphate and ultrasonication has been investigated. Rhodamine B, Methylene Blue dye (basic dyes) and Acid orange II, Acid scarlet red 3R (acid dyes) were used as model compounds in this study. Immobilized cobalt ions, activated the persulphate to form highly reactive sulphate radicals. The degradation studies were conducted with only persulphate (PS), cobalt activated persulphate (PS+Co), persulphate+ultrasonication (PS+US) and cobalt activated persulphate+ultrasonication (PS+US+Co). The decolorisation efficiency were in the order of PS

  2. Removal of Cadmium(II and Lead(II ions from aqueous phase on sodic bentonite

    Directory of Open Access Journals (Sweden)

    Luz Stella Gaona Galindo

    2013-04-01

    Full Text Available This paper describes the adsorption of Cd2+and Pb2+ions using sodic bentonite clay type Fluidgel modified. The Fluidgelbefore and after chemical modification and thermal activation was characterized by different techniques including X-ray diffraction, thermal analysis, Fourier transform infrared, surface area, helium pycnometry, cation exchange capacity and scanning electron microscopy. Pseudo-first order, pseudo-second order and intra-particle diffusion models were used to analyze the kinetic curves. Equilibrium data were analyzed using Langmuir and Freundlich models. The thermodynamic study indicated that lead adsorption process is endothermic and interactions between clays and solutions of lead occurred spontaneously, while cadmium adsorption revealed an exothermic and spontaneous nature. The maximum removal efficiencies were 97.62% for Cd(II using Fluidgelmodified chemically and 91.08% for lead by Fluidgel modified chemical and thermally.

  3. Biosorption of Divalent ion onto Treated Prosopis juliflora Bark from Aqueous Solutions - Isothermal and Statistical Analysis

    Directory of Open Access Journals (Sweden)

    N. Muthulakshmi Andal

    2016-05-01

    Full Text Available The present work emphasizes the utilization of Prosopis juliflora bark, an agro waste material for the adsorption of Cu(II. The raw Prosopis juliflora bark (PJB is treated using 0.1N hydrochloric acid to enhance the sorption efficiency. The characterization studies of TPJB using Scanning Electron Microscopy (SEM, Energy Dispersive X-ray Analysis (EDAX, Brunauer-Emmet-Teller(BET and Barrett-Joyner-Halenda (BJH analyses carried out. The batch mode experimental set up is verified to assess the sorption capacity of the chosen material for the operating factors viz., particle sizes/ doses of the sorbent material upon a range of initial concentrations of Cu(II at different temperatures, agitation time and pH of the Cu(II- TPJB system. The amount of Cu(II ion adsorbed on to TPJB surface is found to be 43.11 mg/g (97.4% under optimized conditions, its efficiency 3 fold times more than the Ce values reported by other researchers. The sorption characteristic of TPJB is quantitatively estimated through column experiments based on the Ce value by batch mode. The removal is observed as 98%. Langmuir, Freundlich and Tempkin isothermal curves at various initial concentrations are plotted for Cu(II-TPJB system wherein the straight line fit is best suited for the Freundlich isotherm model. The results show that the response of TPJB in trapping Cu(II ions are influenced by various parameters being statistically verified using SPSS software, indicative of good correlation.

  4. The use of new modified poly(acrylamide chelating resin with pendent benzothiazole groups containing donor atoms in the removal of heavy metal ions from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Semmedu Selvaraj Kalaivani

    2014-03-01

    Full Text Available The adsorption studies of poly(6-(ethoxybenzothiazole acrylamide (PEBTA, for Cu(II and Zn(II metal ions removal from an aqueous solution have been investigated, as a function of solution pH, adsorbent dose, contact time, initial metal ion concentration and temperature. The chemical and structural characteristics of the adsorbent were determined by the FT-IR, 1H-NMR, TGA, SEM, and EDAX analysis. The maximum adsorption capacities of the adsorbent for Cu(II and Zn(II ions, as calculated from the Langmuir isotherm model, were 273.5 and 216.4 mg/g, respectively. The adsorption kinetic studies show that the adsorption of Cu(II and Zn(II ions onto PEBTA follows the pseudo second order kinetic model. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were also evaluated, and it has been found that the adsorption process is feasible, spontaneous and exothermic in nature. Desorption studies were carried out using 0.3 N HCl, and it revealed that the adsorbed Cu(II and Zn(II ions can be easily removed. The adsorption–desorption process is reversible, and this indicates that PEBTA is an effective adsorbent for the removal of heavy metal ions from an aqueous medium.

  5. Influence of aqueous phase on electrochemical biocorrosion tests in diesel/water systems

    Energy Technology Data Exchange (ETDEWEB)

    Bento, F.M. [Dept. of Soils, Faculty of Agronomy, UFRGS, 7712 Bento Goncalves Avenue, CEP: 91540-001, POA, RS (Brazil); Englert, G.E.; Muller, I.L. [Dept. of Metallurgy, Biocorrosion and Biofilms Lab, UFRGS, 99 Osvaldo Aranha Avenue s.615D, CEP: 90035-190, POA, RS (Brazil); Gaylarde, C.C. [Dept. of Biophisics, UFRGS POA, RS (Brazil)

    2004-08-01

    Storage tanks containing microbially contaminated diesel oil are susceptible to corrosion. This process may be evaluated electrochemically in the laboratory using simulated storage systems containing diesel oil and an aqueous phase. The simulated aqueous phase must supply mineral nutrients for microbial growth, together with adequate electrical conductivity, without, however, being too corrosive, so as to allow the aggressive nature of the microbial metabolites to be detected. In this investigation, microbial growth was measured in six electrically conductive media overlaid with metropolitan diesel oil containing an additive package. The microorganisms were the filamentous fungi, Hormoconis resinae, Paecilomyces variotii and Aspergillus fumigatus, the bacterium Bacillus subtilis and the yeast Candida silvicola, all previously isolated from contaminated diesel oil. After 60 days incubation with pure or mixed inocula of these microorganisms, pH, conductivity and viable microorganisms were measured. The electrochemical behaviour of carbon steel ASTM 283-93-C was determined in each of the six media (uninoculated) and in selected inoculated medium via measurements of open circuit potential and potentiostatic polarization curves. The uptake of phosphate (corrosion inhibitor), microbial growth, pH, conductivity and anodic and cathodic polarization curves were assessed in the water phase after 30 and 60 days of incubation with each single species Aspergillus fumigatus and Hormoconis resinae and with the consortium. The medium which proved most appropriate was Bushnell-Haas medium modified by the omission of chlorides, which allowed satisfactory microbial growth and had low aggressivity towards the steel. The performance of electrochemical tests in aerated, rather than deaerated, electrolyte solutions is suggested to be important to allow the detection of microbial influence on passive film formation and stability. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  6. Adsorption of transition metal ions from aqueous solutions onto a novel silica gel matrix inorganic-organic composite material.

    Science.gov (United States)

    Yin, Ping; Xu, Qiang; Qu, Rongjun; Zhao, Guifang; Sun, Yanzhi

    2010-01-15

    A novel inorganic-organic composite material silica gel microspheres encapsulated by imidazole functionalized polystyrene (SG-PS-azo-IM) has been synthesized and characterized. This composite material was used to investigate the adsorption of Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II), Hg(II), Pb(II), Pd(II), Pt(II), Ag(I), and Au(III) from aqueous solutions, and the research results displayed that SG-PS-azo-IM has the highest adsorption capacity for Au(III). Langmuir and Freundlich isotherm models were applied to analyze the experimental data, the best interpretation for the experimental data was given by the Langmuir isotherm equation, and the maximum adsorption capacity for Au(III) is 1.700 mmol/g. The adsorption selectivity, the dynamic adsorption and desorption properties of SG-PS-azo-IM for Au(III) have also been studied. The results showed that SG-PS-azo-IM had excellent adsorption for Au(III) in four binary ions system, especially in the systems of Au(III)-Zn(II) and Au(III)-Cu(II), and almost Au(III) could be desorbed with the eluent solution of 0.5% thiourea in 1 mol/L HCl. Moreover, this novel composite material was used to preconcentrate Au(III) before its determination by flame atomic adsorption spectrometry. In the initial concentration range of 0.10-0.20 microg/mL, multiple of enrichment could reach 5.28. Thus, silica gel encapsulated by polystyrene coupling with imidazole (SG-PS-azo-IM) is favorable and useful for the removal of transition metal ions, and the high adsorption capacity makes it a good promising candidate material for Au(III) removal.

  7. Ion-pair formation in aqueous strontium chloride and strontium hydroxide solutions under hydrothermal conditions by AC conductivity measurements.

    Science.gov (United States)

    Arcis, H; Zimmerman, G H; Tremaine, P R

    2014-09-01

    Frequency-dependent electrical conductivities of solutions of aqueous strontium hydroxide and strontium chloride have been measured from T = 295 K to T = 625 K at p = 20 MPa, over a very wide range of ionic strength (3 × 10(-5) to 0.2 mol kg(-1)), using a high-precision flow AC conductivity instrument. Experimental values for the concentration-dependent equivalent conductivity, Λ, of the two electrolytes were fitted with the Turq-Blum-Bernard-Kunz ("TBBK") ionic conductivity model, to determine ionic association constants, K(A,m). The TBBK fits yielded statistically significant formation constants for the species SrOH(+) and SrCl(+) at all temperatures, and for Sr(OH)2(0) and SrCl2(0) at temperatures above 446 K. The first and second stepwise association constants for the ion pairs followed the order K(A1)(SrOH(+)) > K(A1)(SrCl(+)) > K(A2)[Sr(OH)2(0)] > K(A2)[SrCl2(0)], consistent with long-range solvent polarization effects associated with the lower static dielectric constant and high compressibility of water at elevated temperatures. The stepwise association constants to form SrCl(+) agree with previously reported values for CaCl(+) to within the combined experimental error at high temperatures and, at temperatures below ∼375 K, the values of log10 KA1 for strontium are lower than those for calcium by up to ∼0.3-0.4 units. The association constants for the species SrOH(+) and Sr(OH)2(0) are the first accurate values to be reported for hydroxide ion pairs with any divalent cation under these conditions.

  8. Sequestering of thorium ions from aqueous media on rice husk. Equilibrium, kinetic and thermodynamic studies

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, Shagufta; Mirza, Muhammad Latif [The Islamia University of Bahawalpur (Pakistan). Dept. of Chemistry; Khalid, Nasir [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

    2015-07-01

    The adsorption behaviour of thorium on rice husk has been studied by optimizing different parameters like nature of electrolyte, amount of adsorbent, equilibration time, metal concentration, and temperature, employing batch method and radiotracer technique. Maximum adsorption was observed at 0.0001 mol L{sup -1} HNO{sub 3}, using 0.1 g of adsorbent for 4 cm{sup 3} of 5.19 x 10{sup -5} mol L{sup -1} of Th{sup +4} solution in fifteen minutes equilibration time. The adsorption phenomenon was verified by FTIR, SEM and EDX techniques. The adsorption data was well fitted to Freundlich, Langmuir and Dubinin-Radushkevich isotherm equations. The characteristic Freundlich constants i.e. 1/n = 0.528 ± 0.019 and K = 4.88 x 10{sup -4} ± 1.29 x 10{sup -5} mol g{sup -1} whereas the Langmuir constants Q{sub m} = (4.159 ± 0.234) x 10{sup -6} mol g{sup -1} and K{sub L} = (3.627 ± 0.328) x 10{sup 4} dm{sup 3} mol{sup -1} have been computed for the sorption system. The sorption free energy was found to be 11.24 ± 0.211 kJ mol{sup -1} showing chemisorption nature of interaction between thorium and rice husk. The results showed that thorium adsorption on rice husk follows pseudo 2{sup nd} order with rate constant = 1.448 g mg{sup -1} min{sup -1}. The determined negative values of ΔG indicated spontaneity of the process, whereas the positive values of ΔH and ΔS confirmed endothermic nature and increased randomness during the adsorption process respectively. The removal of Th{sup +4} ions from spiked tap water was checked by employing the optimized experimental parameters which indicated that rice husk is a good adsorbent for thorium ions and may be used for waste management of radionuclides.

  9. Improvement on simultaneous determination of chromium species in aqueous solution by ion chromatography and chemiluminescence detection

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Liao, Y.P.; Jons, O.

    1997-01-01

    A sensitive method for the simultaneous determination of chromium(III) and chromium(VI) was chromatography and chemiluminescence detection. Two Dionex ion-exchange guard columns in series, CG5 and AG7, were used to separate chromium(III) from chromium(VI). Chromium(VI) was reduced by potassium......, the stabilities of reductant and luminol solutions were studied. The linear range of the calibration curve for chromium(III) and chromium(VI) was 1-400 mu g l(-1). The detection limit was 0.12 mu g l(-1) for chromium(III) and 0.09 mu g l(-1) for chromium(VI), respectively. The precision at the 20 mu g l(-1) level...... was 1.4% for chromium(III) and 2.5% for chromium(VI), respectively. The accuracy of the chromium(III) determination was determined by analysis of the NIST standard reference material 1643c, Trace elements in water with the result 19.1 +/- 1.0 mu g Cr(III) l(-1) (certified value 19.0 +/- 0.6 mu g Cr...

  10. Pengaruh Temperatur Hydrothermal Terhadap Performa Elektrokimia Lifepo4 Sebagai Katoda Baterai Ion Lithium Type Aqueous Elektrolit

    Directory of Open Access Journals (Sweden)

    Hendro Waluyo

    2014-09-01

    Full Text Available Katoda yang biasa digunakan produsen baterai lithium saat ini adalah LiCoO2. Dimana LiCoO2 memilki beberapa kekurangan beracun, tidak stabil, dan harganya mahal. Bahan katoda yang sangat menjanjikan adalah lithium iron phosphate (LiFePO4 untuk bisa menggantikan LiCoO2 .Dalam proses sintesis katoda LiFePO4 pada penelitian ini menggunakan metode hydrothermal dengan variasi temperatur 1500C,1750C dan 2000C selama 12 jam untuk waktu holdingnya. Dari hasil pengujian XRD menunjukkan terbentuknya fase LiFePO4 pada semua sampel, namun masih ditemukan zat pengotor. Untuk hasil uji SEM, serbuk LiFePO4 memiliki bentuk bulat tidak beraturan dan terjadi aglomerasi. Serbuk LiFePO4 dengan variasi temperatur 2000C memiliki performance yang paling baik dengan nilai kapasitas sebesar 109.32 mA/g hal ini karena dari hasil CV menunjukkan kinetik tranfer ion Lithium yang baik akibat distribusi ukuran partikel yang merata dan juga tingkat kristanilitas yang tinggi.

  11. New Calix[4]arene dibenzocrown ethers for selective sensing of cesium ion in aqueous environment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Seung; Kim, Jong Kuk [Konyang University, Nonsan (Korea, Republic of); Choi, Wang Kyu; Lee, Kune Woo; Oh, Won Jin [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    1,3-dialkoxycalix[4]arene dibenzocrown ethers (6-9) were successfully synthesized in the fixed 1,3-alternate conformation with over 90% yields by the reaction of corresponding 1,3dialkoxycalix[4]arenes 2-5 with dibenzodimesylate 13 in acetonitrile as a solvent in the presence of cesium carbonate as a base. In view of cyclization yield, the use of dimesylate is found to be better than that of dibenzoditosylate. With an unusual AB pattern in {sup 1}H NMR spectrum for compound 9, it is suggested that conformational structure of 1,3-diallyloxycalix[4]arene dibenzocrown ether be less flexible than that of usual 1,3-alternate calixcrown ether, probably due to steric effects of two ally1 group. Complexation of the corresponding calix[4]arene 6-9 toward alkali metal ions using single flux method through bulk liquid membrane system was found to give a high cesium selectivity. 28 refs., 1 tab., 1 fig.

  12. Preparation and adsorption properties of nano magnetite chitosan films for heavy metal ions from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Lasheen, M.R., E-mail: ragaei24@link.net [Water Pollution Research Department, Environmental Research Division, National Research Centre, 33-El Buhoth St., Dokki, Cairo, 12311 (Egypt); El-Sherif, Iman Y., E-mail: iman57us@yahoo.com [Water Pollution Research Department, Environmental Research Division, National Research Centre, 33-El Buhoth St., Dokki, Cairo, 12311 (Egypt); Tawfik, Magda E., E-mail: magdaemileta@yahoo.com [Polymers and Pigments Department, National Research Centre, 33-El Buhoth St., Dokki, Cairo, 12311 (Egypt); El-Wakeel, S.T., E-mail: shaimaa_tw@yahoo.com [Water Pollution Research Department, Environmental Research Division, National Research Centre, 33-El Buhoth St., Dokki, Cairo, 12311 (Egypt); El-Shahat, M.F., E-mail: elshahatmf@hotmail.com [Faculty of Science, Ain Shams University, Khalifa El-Maamon St., Abbasiya Sq., 11566, Cairo (Egypt)

    2016-08-15

    Highlights: • Nano magnetite–chitosan films were prepared by casting method. • The efficiency of the prepared films for removing heavy metals was investigated. • The adsorption mechanism was studied using different isotherm and kinetic models. • Films reuse and metals recovery were studied. - Abstract: Nano magnetite chitosan (NMag–CS) film was prepared and characterized with different analytical methods. X-ray diffraction (XRD) patterns confirmed the formation of a pure magnetite structure and NMag–CS nanocomposite. TEM image of the film, revealed the uniform dispersion of magnetite nanoparticles inside chitosan matrix. The adsorption properties of the prepared film for copper, lead, cadmium, chromium and nickel metal ions were evaluated. Different factors affecting the uptake behavior by the composite films such as time, initial pH and film dose were investigated. The adsorption equilibrium attained using 2 g/L of the film after 120 min of reaction. The equilibrium data were analyzed using Langmuir and Freundlich models. The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all metals. The metals regenerated from films with an efficiency greater than 95% using 0.1 M ethylene diamine tetra acetic acid (EDTA) and films were successfully reused for adsorption.

  13. Three-dimensional printed knotted reactors enabling highly sensitive differentiation of silver nanoparticles and ions in aqueous environmental samples

    Energy Technology Data Exchange (ETDEWEB)

    Su, Cheng-Kuan, E-mail: chengkuan@ntou.edu.tw [Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, 20224, Taiwan, ROC (China); Hsieh, Meng-Hsuan [Department of Biomedical Engineering and Environmental Sciences, National Tsing-Hua University, Hsinchu, 30013, Taiwan, ROC (China); Sun, Yuh-Chang, E-mail: ycsun@mx.nthu.edu.tw [Department of Biomedical Engineering and Environmental Sciences, National Tsing-Hua University, Hsinchu, 30013, Taiwan, ROC (China)

    2016-03-31

    Whether silver nanoparticles (AgNPs) persist or release silver ions (Ag{sup +}) when discharged into a natural environment has remained an unresolved issue. In this study, we employed a low-cost stereolithographic three-dimensional printing (3DP) technology to fabricate the angle-defined knotted reactors (KRs) to construct a simple differentiation scheme for quantitative assessment of Ag{sup +} ions and AgNPs in municipal wastewater samples. We chose xanthan/phosphate-buffered saline as a dispersion medium for in situ stabilization of the two silver species, while also facilitating their extraction from complicated wastewater matrices. After method optimization, we measured extraction efficiencies of 54.5 and 32.3% for retaining Ag{sup +} ions and AgNPs, respectively, in the printed KR (768-turn), with detection limits (DLs) of 0.86 and 0.52 ng L{sup −1} when determining Ag{sup +} ions and AgNPs, respectively (sample run at pH 11 without a rinse solution), and 0.86 ng L{sup −1} when determining Ag{sup +} ions alone (sample run at pH 12 with a 1.5-mL rinse solution). The proposed scheme is tolerant of the wastewater matrix and provides more reliable differentiation between Ag{sup +}/AgNPs than does a conventional filtration method. The concept and applicability of adopting 3DP technology to renew traditional KR devices were evidently proven by means of these significantly improved analytical performance. Our analytical data suggested that the concentrations of Ag{sup +} ions and AgNPs in the tested industrial wastewater sample were both higher than those in domestic wastewater, implying that industrial activity might be a main source of environmental silver species, rather than domestic discharge from AgNP-containing products. - Highlights: • 3D printed knotted reactors are utilized to differentiate AgNPs and Ag{sup +} ions. • Xanthan/phosphate-buffered saline is used for stabilizing the two silver species. • Extraction efficiency up to 54.5% is

  14. Photoreduction of Cr(VI Ions in Aqueous Solutions by UV/TiO2 Photocatalytic Processes

    Directory of Open Access Journals (Sweden)

    Chih Ming Ma

    2012-01-01

    Full Text Available This study discussed the photoreduction of Cr(VI ions in aqueous solutions by UV/TiO2 photocatalytic processes under various operational factors. Experimental results showed that the removal rate of Cr(VI increased with decreasing solution pH values and with increasing dosages of organic compounds, indicating that the recombination rate of electrons and h+ can be retarded in the reaction systems by the addition of the scavenger, thus raising the reaction rate of Cr(VI. The relationship of the chemical reaction rate of Cr(VI, TiO2 dosage, and changes of Cr(VI concentration was expressed by the pseudo-first-order kinetic equation. Comparing the experimental results of two different doping metals in modified TiO2 photoreduction systems, the removal rate of Cr(VI by the Ag/TiO2 process is larger, possibly because the electron transferring ability of Ag is superior to that of Cu. However, the photoreduction rates of Cr(VI by modified UV/TiO2 processes are worse than those by a nonmodified commercial UV/TiO2 process.

  15. Removal of Pb(II) ions from aqueous solution using activated tea waste: Adsorption on a fixed-bed column.

    Science.gov (United States)

    Mondal, M K

    2009-08-01

    An inexpensive and effective adsorbent was developed from waste tea leaves for the dynamic uptake of Pb(II). Characterization of the adsorbents showed a clear change between physico-chemical properties of activated tea waste and simply tea waste. The purpose of this work was to evaluate the potential of activated tea waste in continuous flow removal of Pb(II) ions from synthetic aqueous effluents. The performance of the system was evaluated to assess the effect of various process variables, viz., of bed height, hydraulic loading rate and initial feed concentration on breakthrough time and adsorption capacity. The shape of the breakthrough curves was determined for the adsorption of Pb(II) by varying different operating parameters like hydraulic loading rate (2.3-9.17m(3)/hm(2)), bed height (0.3-0.5m) and feed concentration (2-10mg/l). An attempt has also been made to model the data generated from column studies using the empirical relationship based on the Bohart-Adams model. There was an acceptable degree of agreement between the data for breakthrough time calculated from the Bohart-Adams model and the present experimental study with average absolute deviation of less than 5.0%. The activated tea waste in this study showed very good promise as compared with the other adsorbents available in the literature. The adsorbent could be suitable for repeated use (for more than four cycles) without noticeable loss of capacity.

  16. Hydration and ion pair formation in common aqueous La(III) salt solutions--a Raman scattering and DFT study.

    Science.gov (United States)

    Rudolph, Wolfram W; Irmer, Gert

    2015-01-01

    Raman spectra of aqueous lanthanum perchlorate, triflate (trifluorosulfonate), chloride and nitrate solutions were measured over a broad concentration (0.121-3.050 mol L(-1)) range at room temperature (23 °C). A very weak mode at 343 cm(-1) with a full width at half height at 49 cm(-1) in the isotropic spectrum suggests that the nona-aqua La(III) ion is thermodynamically stable in dilute perchlorate solutions (∼0.2 mol L(-1)) while in concentrated perchlorate solutions outer-sphere ion pairs and contact ion pairs are formed. The La(3+) nona-hydrate was also detected in a 1.2 mol L(-1) La(CF3SO3)3(aq). In lanthanum chloride solutions chloro-complex formation was detected over the measured concentration range from 0.5-3.050 mol L(-1). The chloro-complexes in LaCl3(aq) are fairly weak and disappear with dilution. At a concentration complexes disappeared. In LaCl3 solutions, with additional HCl, a series of chloro-complexes of the type [La(OH2)(9-n)Cln](+3-n) (n = 1-3) were formed. The La(NO3)3(aq) spectra were compared with a spectrum of a 0.409 mol L(-1) NaNO3(aq) and it was concluded that in La(NO3)3(aq) over the concentration range from 0.121-1.844 mol L(-1), nitrato-complexes, [La(OH2)(9-n)(NO3)n](+3-n) (n = 1, 2) were formed. These nitrato-complexes are quite weak and disappear with dilution La(OH2)9](3+) with the polarizable dielectric continuum are in good agreement with data from recent structural experimental measurements and high quality simulations. The DFT frequency of the La-O stretching mode at 328.2 cm(-1), is only slightly smaller than the experimental one.

  17. Evaluation of carbon-based nanosorbents synthesised by ethylene decomposition on stainless steel substrates as potential sequestrating materials for nickel ions in aqueous solution

    Institute of Scientific and Technical Information of China (English)

    X.J.Lee; L.Y.Lee; L.P.Y.Foo; K.W.Tan; D.G.Hassell

    2012-01-01

    The present work covers the preparation of carbon-based nanosorbents by ethylene decomposition on stainless steel mesh without the use of external catalyst for the treatment of water containing nickel ions (Ni2+).The reaction temperature was varied from 650 to 850℃,while reaction time and ethylene to nitrogen flow ratio were maintained at 30 min and 1:1 cm3/min,respectively.Results show that nanosorbents synthesised at a reaction temperature of 650℃ had the smallest average diameter (75 nm),largest BET surface area (68.95m2/g) and least amount of impurity (0.98 wt.% Fe).A series of batch sorption tests were performed to evaluate the effects of initial pH,initial metal concentration and contact time on Ni2+ removal by the nanosorbents.The equilibrium data fitted well to Freundlich isotherm.The kinetic data were best correlated to a pseudo second-order model indicating that the process was of chemisorption type.Further analysis by the Boyd kinetic model revealed that boundary layer diffusion was the controlling step.This primary study suggests that the prepared material with Freundlich constants compared well with those in the literature,is a promising sorbent for the sequestration of Ni2+ in aqueous solutions.

  18. Na3Ti2(PO4)(3) as a sodium-bearing anode for rechargeable aqueous sodium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z; Ravnsbaek, DB; Xiang, K; Chiang, YM

    2014-07-01

    Na3Ti2(PO4)(3) synthesized as fine carbon-coated powders is demonstrated for the first time to be a suitable sodium-bearing anode material for rechargeable aqueous sodium-ion batteries (ANaBs). Importantly, Na3Ti2(PO4)(3) is found to be stable in deoxygenated water, enabling use of this material in aqueous systems. As a sodiated anode, it allows use of sodium-depleted cathode materials that require supply of sodium-ions from the anode. As an example, we demonstrate for the first time the use of olivine FePO4 as a cathode in an ANaB. (C) 2014 Elsevier B.V. All rights reserved.

  19. Histidine-modified organic-silica hybrid monolithic column for mixed-mode per aqueous and ion-exchange capillary electrochromatography.

    Science.gov (United States)

    Tang, Sheng; Liu, Shujuan; Liang, Xiaojing; Tang, Xiaofen; Wu, Xingcai; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2015-06-01

    A novel organic-silica hybrid monolith was prepared through the binding of histidine onto the surface of monolithic matrix for mixed-mode per aqueous and ion-exchange capillary electrochromatography. The imidazolium and amino groups on the surface of the monolithic stationary phase were used to generate an anodic electro-osmotic flow as well as to provide electrostatic interaction sites for the charged compounds at low pH. Typical per aqueous chromatographic behavior was observed in water-rich mobile phases. Various polar and hydrophilic analytes were selected to evaluate the characteristics and chromatographic performance of the obtained monolith. Under per aqueous conditions, the mixed-mode mechanism of hydrophobic and ion-exchange interactions was observed and the resultant monolithic column proved to be very versatile for the efficient separations of these polar and hydrophilic compounds (including amides, nucleosides and nucleotide bases, benzoic acid derivatives, and amino acids) in highly aqueous mobile phases. The successful applications suggested that the histidine-modified organic-silica hybrid monolithic column could offer a wide range of retention behaviors and flexible selectivities toward polar and hydrophilic compounds.

  20. A highly selective chemodosimeter for fast detection and intracellular imaging of Hg2+ ions based on a dithiocarbamate-isothiocyanate conversion in aqueous ethanol.

    Science.gov (United States)

    Pal, Suman; Hatai, Joydev; Samanta, Mousumi; Shaurya, Alok; Bandyopadhyay, Subhajit

    2014-02-21

    A new naphthalene diimide-dithiocarbamate based fluorescence probe was synthesized and its fluorogenic behavior towards various metal ions was studied. Upon addition of various metal ions, the probe afforded an irreversible change only with Hg(2+) ions in aqueous-ethanol media (4 : 1 v/v) with a fourfold enhancement of the fluorescence (Φ = 0.03 → 0.11) along with a distinct 43 nm blue shift of the emission maxima. The mechanism of the chemodosimetric behavior of the probe has been attributed to a Hg(2+) induced transformation of a weakly fluorescent dithiocarbamate to a highly fluorescent isothiocyanate which has been characterized by a number of spectroscopic techniques and a crystal structure. Intracellular detection of Hg(2+) ions was achieved using the probe.

  1. A study of low-energy ion induced radiolysis of thiol-containing amino acid cysteine in the solid and aqueous solution states

    Energy Technology Data Exchange (ETDEWEB)

    Ke Zhigang [Key Laboratory of Ion Beam Bio-engineering, Institute of Plasma Physics of Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1126, Hefei 230031 (China); Huang Qing, E-mail: huangq@ipp.ac.c [Key Laboratory of Ion Beam Bio-engineering, Institute of Plasma Physics of Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1126, Hefei 230031 (China); Dang Bingrong [Institute of Modern Physics, Chinese Academy of Sciences, 509 Nanchang Road, Lanzhou 730000 (China); Lu Yilin [Key Laboratory of Ion Beam Bio-engineering, Institute of Plasma Physics of Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1126, Hefei 230031 (China); Department of Physics, Anhui University, Hefei 230031 (China); Yuan Hang; Zhang Shuqing; Yu Zengliang [Key Laboratory of Ion Beam Bio-engineering, Institute of Plasma Physics of Chinese Academy of Sciences, 350 Shushanhu Road, P.O. Box 1126, Hefei 230031 (China)

    2010-09-15

    The radiolysis of cysteine under plasma discharge and irradiation of low-energy ion beam was investigated. The damage of cysteine in aqueous solution under discharge was assessed via the acid ninhydrin reagent and the yield of cystine produced from the reaction was analyzed by FTIR. In addition, the generation of hydrogen sulfide was also identified. The destruction of solid cysteine under low-energy ion beam irradiation was estimated via monitoring IR bands of different functional groups (-SH, -NH{sub 3}, -COO{sup -}) of cysteine, and the production of cystine from ion-irradiated solid cysteine after dissolution in water was also verified. These results may help us to understand the inactivation of sulphydryl enzymes under direct and indirect interaction with the low-energy ion irradiation.

  2. Kinetic modeling of the biosorption of Cd2+ ions from aqueous solutions onto Eichhornia crassipes roots using potentiometry: low-cost alternative to conventional methods

    Directory of Open Access Journals (Sweden)

    Carolina Martínez-Sánchez

    2013-01-01

    Full Text Available This work presents the use of potentiometric measurements for kinetic studies of biosorption of Cd2+ ions from aqueous solutions on Eichhornia crassipes roots. The open circuit potential of the Cd/Cd2+ electrode of the first kind was measured during the bioadsorption process. The amount of Cd2+ ions accumulated was determined in real time. The data were fit to different models, with the pseudo-second-order model proving to be the best in describing the data. The advantages and limitations of the methodology proposed relative to the traditional method are discussed.

  3. Thermodynamics of ion exchange between clinoptilolite and aqueous solutions of Na{sup +}/K{sup +} and Na{sup +}/Ca{sup 2+}

    Energy Technology Data Exchange (ETDEWEB)

    Pabalan, R.T. [Southwest Research Institute, San Antonio, TX (United States)

    1994-11-01

    Because of their ion-exchange, adsorption, and molecular sieve properties, zeolite minerals have generated worldwide interest for use in a broad range of applications such as nuclear and municipal waste water treatment, stack-gas cleanup, natural gas purification, petroleum production, and in agriculture and aquaculture. To provide a thermodynamic basis for understanding zeolite-water interactions in geologic systems, ion-exchange experiments were conducted at 25{degrees}C between clinoptilolite, which is the predominant zeolite mineral in altered pyroclastic and volcaniclastic rocks, and aqueous mixtures of Na{sup +}/K{sup +} and Na{sup +}/Ca{sup 2+}. Isotherm points were obtained by equilibrating Na-clinoptilolite, which was prepared from clinoptilolite-rich tuff from Death Valley Junction, California, USA, and Na{sup +}/K{sup +} and Na{sup +}/Ca{sup 2+} chloride solutions having different ionic concentration ratios, but constant total normalities of 0.5, 0.05, or 0.005 N. The experimental data were interpreted using a Margules thermodynamic formulation for zeolite solid solutions, coupled with the Pitzer model for aqueous activity coefficients. The isotherm data for 0.5 N Na{sup +}/K{sup +} and Na{sup +}/Ca{sup 2+} solutions were used to derive equilibrium constants and Gibbs free energies for the ion-exchange reactions, as well as parameters for the Margules model. Using the same parameters derived from the 0.5 N data, isotherms were calculated for the 0.05 and 0.005 N solutions. The predicted values agree very well with experimental data. The results of this study indicate that a Margules solid solution model for zeolites, coupled with an activity coefficient model for aqueous solutions (e.g., Pitzer model), can successfully describe and predict binary ion-exchange equilibria between aqueous solutions and the zeolite mineral clinoptilolite over a wide range of solution composition and concentration.

  4. Development of Low Cost Adsorbent from Cow Horn for the Biosorption of Mn (II, Ni (II and Cd (II Ion from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Jimoh. O. Tijani

    2014-01-01

    Full Text Available Development of low cost adsorbent from cow horn for the biosorption of Mn (II, Ni (II and Cd (II ion aqueous solution was carried out by batch adsorption experiment at 32°C. Parameters such as pH, contact time, metal ion concentrations as well as temperature were monitored. The residual concentration of Mn (II, Ni (II and Cd (II were determined using Atomic Absorption Spectrophotometer. The results revealed that maximum Ni (II and Cd (II ion removal occurred at pH of 6 while Mn (II ion occurred at pH of 7 respectively. Langmuir and Temkin adsorption isotherm were used to describe the equilibrium data. The equilibrium data fitted well to Langmuir isotherm than Temkin isotherm. Thermodynamic investigation showed that standard Gibbs free energy (∆G˚ was positive indicating the feasibility and non-spontaneous of the process. The positive value of standard Enthalpy (∆H˚ implies that the reaction was endothermic and the negative standard Entropy (∆S˚ signifies decrease in the randomness at the solid/solution interface of the adsorbent during the adsorption process. The kinetic study revealed that adsorption of Mn (II, Ni (II and Cd (II could be best described by pseudo-second model. This study demonstrated that adsorbent developed from cow horn could be used as an alternative to commercial activated carbon in the removal of Mn (II, Ni (II and Cd (II ions from aqueous solution.

  5. Characteristics of lithium-ion batteries during fire tests

    Science.gov (United States)

    Larsson, Fredrik; Andersson, Petra; Blomqvist, Per; Lorén, Anders; Mellander, Bengt-Erik

    2014-12-01

    Commercial lithium-ion battery cells are exposed to a controlled propane fire in order to evaluate heat release rate (HRR), emission of toxic gases as well as cell temperature and voltage under this type of abuse. The study includes six abuse tests on cells having lithium-iron phosphate (LFP) cathodes and, as a comparison, one test on conventional laptop battery packs with cobalt based cathode. The influence of different state of charge (SOC) is investigated and a limited study of the effect of water mist application is also performed. The total heat release (THR) per battery energy capacity are determined to be 28-75 kJ Wh-1 and the maximum HRR values to 110-490 W Wh-1. Hydrogen fluoride (HF) is found in the released gases for all tests but no traceable amounts of phosphorous oxyfluoride (POF3) or phosphorus pentafluoride (PF5) are detected. An extrapolation of expected HF emissions for a typical automotive 10 kWh battery pack exposed to fire gives a release of 400-1200 g HF. If released in a confined environment such emissions of HF may results in unacceptable exposure levels.

  6. Electroanalytical tools to investigate the divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions in non-aqueous medium

    Institute of Scientific and Technical Information of China (English)

    Jignasu P Mehta; Himanshu M Pandya; Kahan I Pandya

    2012-01-01

    The divalent state of Ln(Ⅲ) ions has attracted much interest because of their ability to serve isomorphously in many biological system of divalent Ca(Ⅱ) ion.Therefore,present paper deals with the study of divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions in non-aqueous medium.In present study,cyclic voltammetry and chronopotentiometry were utilized to establish the divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions.The cyclic voltammetric technique showed two-step reduction process at cathode for both Ln(Ⅲ) ions under specified experimental conditions and chronopotentiomeuic method also showed two different transition times (τ).Looking to the shape of cyclic voltammogram we calculated heterogeneous forward rate constant (K0fh,cm/s) and diffusion coefficient (D,cm2/s) for both ions,which suggested that sweep rate had great effect on the shape of cyclic voltammogram of Eu(Ⅲ) and Nd(Ⅲ) ions.The result of chronopotentiometry also suggested that stable divalent states of Eu(Ⅲ) and Nd(Ⅲ) ions existed with chronopotenuogram with two distinct transition times.The diffusion coefficients (D,cm2/s)were calculated from Sand equation.The diffusion coefficients of both techniques were compared and the results suggested that the system at electrode surface was changing from being reversible to irreversible.

  7. Multi-Species Test of Ion Cyclotron Resonance Heating at High Altitudes

    Science.gov (United States)

    Persoon, A. M.; Peterson, W. K.; Andre, M.; Chang, T.; Gurnett, D. A.; Retterer, J. M.; Crew, G. B.

    1997-01-01

    Observations of ion distributions and plasma waves obtained by the Dynamics Explorer 1 satellite in the high-altitude, nightside auroral zone are used to study ion energization for three ion species. A number of theoretical models have been proposed to account for the transverse heating of these ion populations. One of these, the ion cyclotron resonance heating (ICRH) mechanism, explains ion conic formation through ion cyclotron resonance with broadband electromagnetic wave turbulence in the vicinity of the characteristic ion cyclotron frequency. The cyclotron resonant heating of the ions by low-frequency electromagnetic waves is an important energy source for the transport of ions from the ionosphere to the magnetosphere. In this paper we test the applicability of the ICRH mechanism to three simultaneously heated and accelerated ion species by modelling the ion conic formation in terms of a resonant wave-particle interaction in which the ions extract energy from the portion of the broadband electromagnetic wave spectrum which includes the ion cyclotron frequency. Using a Monte Carlo technique we evaluate the ion heating produced by the electromagnetic turbulence at low frequencies and find that the wave amplitudes near the ion cyclotron frequencies are sufficient to explain the observed ion energies.

  8. Functionalized macroporous copolymer of glycidyl methacrylate: The type of ligand and porosity parameters influence on Cu(II ion sorption from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Sandić Zvjezdana P.

    2009-01-01

    Full Text Available The removal of heavy metals from hydro-metallurgical and other industries' wastewaters, their safe storage and possible recovery from waste- water streams is one of the greater ecological problems of modern society. Conventional methods, like precipitation, adsorption and biosorption, electrowinning, membrane separation, solvent extraction and ion exchange are often ineffective, expensive and can generate secondary pollution. On the other hand, chelating polymers, consisting of crosslinked copolymers as a solid support and functional group (ligand, are capable of selectively loading different metal ions from aqueous solutions. In the relatively simple process, the chelating copolymer is contacted with the contaminated solution, loaded with metal ions, and stripped with the appropriate eluent. Important properties of chelating polymers are high capacity, high selectivity and fast kinetics combined with mechanical stability and chemical inertness. Macroporous hydrophilic copolymers of glycidyl methacrylate and ethylene glycol dimethacrylate modified by different amines show outstanding efficiency and selectivity for the sorption of precious and heavy metals from aqueous solutions. In this study poly(GMA-co-EGDMA copolymers were synthesized with different porosity parameters and functionalized in reactions with ethylene diamine (EDA, diethylene triamine (DETA and triethylene tetramine (TETA. Under non-competitive conditions, in batch experiments at room temperature, the rate of sorption of Cu(II ions from aqueous solutions and the influence of pH on it was determined for four samples of amino-functionalized poly(GMA-co-EGDMA. The sorption of Cu(II for both amino-functionalized samples was found to be very rapid. The sorption half time, t1/2, defined as the time required to reach 50% of the total sorption capacity, was between 1 and 2 min. The maximum sorption capacity for copper (2.80 mmol/g was obtained on SGE-10/12-deta sample. The sorption

  9. Removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution using rice husk-based activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Taha, Mohd F., E-mail: faisalt@petronas.com.my; Shaharun, Maizatul S. [Fundamental and Applied Sciences Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Perak Darul Ridzuan (Malaysia); Shuib, Anis Suhaila, E-mail: anisuha@petronas.com.my; Borhan, Azry [Chemical Engineering Department, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, 31750, Perak Darul Ridzuan (Malaysia)

    2014-10-24

    An attempt was made to investigate the potential of rice husk-based activated carbon as an alternative low-cost adsorbent for the removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Rice husk-based activated carbon was prepared via treatment of rice husk with NaOH followed by the carbonization process at 400°C for 2 hours. Three samples, i.e. raw rice husk, rice husk treated with NaOH and rice husk-based activated carbon, were analyzed for their morphological characteristics using field-emission scanning electron microscope/energy dispersive X-ray (FESEM/EDX). These samples were also analyzed for their carbon, hydrogen, nitrogen, oxygen and silica contents using CHN elemental analyzer and FESEM/EDX. The porous properties of rice husk-based activated carbon were determined by Brunauer-Emmett-Teller (BET) surface area analyzer, and its surface area and pore volume were 255 m{sup 2}/g and 0.17 cm{sup 2}/g, respectively. The adsorption studies for the removal of Ni(II), Zn(II) and Pb(II) ions from single metal aqueous solution were carried out at a fixed initial concentration of metal ion (150 ppm) with variation amount of adsorbent (rice husk-based activated carbon) as a function of varied contact time at room temperature. The concentration of each metal ion was analyzed using atomic absorption spectrophotometer (AAS). The results obtained from adsorption studies indicate the potential of rice husk as an economically promising precursor for the preparation of activated carbon for removal of Ni(II), Zn(II) and Pb(II) ions from single aqueous solution. Isotherm and kinetic model analyses suggested that the experimental data of adsorption studies fitted well with Langmuir, Freundlich and second-order kinetic models.

  10. Radiation crosslinked poly (vinyl alcohol/acrylic acid copolymer for removal of heavy metal ions from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Yahya H.F. Al-qudah

    2014-04-01

    Full Text Available Poly(vinyl alcohol and acrylic acid (AAc were copolymerized in different compositions using gamma irradiation. Swelling characteristics of the obtained polymeric hydrogels (PVA/AAc were evaluated and showed reasonable sensitivity to both pH and temperature. The diffusion of water within the hydrogel was found to be of Fickian character, the water molecules may simply diffuse through the polymer network by diffusion processes. The adsorption of Zn2+, Co2+ and Mn2+ ions onto (PVA/AAc has been investigated. The parameters studied including; the effects of pH, contact time and the initial metal ion concentrations by batch method. It was found that the adsorption of Zn2+, Co2+ and Mn2+ ions by PVA/AAc hydrogel is pH-dependent and the maximum sorption of Zn2+, Co2+ and Mn2+ was found to be 388, 245 and 152 mg/g, respectively, at pH 5. The adsorption studies are fitted in various adsorption models such as Langmuir and Freundlich. The kinetic data was tested using pseudo-first-order, pseudo-second-order kinetic models and an intraparticle diffusion model. The correlation results suggested that the pseudo-second-order model was the best choice among all the kinetic models to describe the adsorption behavior.

  11. Effect of pyrophosphate ions on the conversion of calcium-lithium-borate glass to hydroxyapatite in aqueous phosphate solution.

    Science.gov (United States)

    Fu, Hailuo; Rahaman, Mohamed N; Day, Delbert E; Huang, Wenhai

    2010-10-01

    The conversion of glass to a hydroxyapatite (HA) material in an aqueous phosphate solution is used as an indication of the bioactive potential of the glass, as well as a low temperature route for preparing biologically useful materials. In this work, the effect of varying concentrations of pyrophosphate ions in the phosphate solution on the conversion of a calcium-lithium-borate glass to HA was investigated. Particles of the glass (150-355 μm) were immersed for up to 28 days in 0.25 M K(2)HPO(4) solution containing 0-0.1 M K(4)P(2)O(7). The kinetics of degradation of the glass particles and their conversion to HA were monitored by measuring the weight loss of the particles and the ionic concentration of the solution. The structure and composition of the conversion products were analyzed using X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. For K(4)P(2)O(7) concentrations of up to 0.01 M, the glass particles converted to HA, but the time for complete conversion increased from 2 days (no K(4)P(2)O(7)) to 10 days (0.01 M K(4)P(2)O(7)). When the K(4)P(2)O(7) concentration was increased to 0.1 M, the product consisted of an amorphous calcium phosphate material, which eventually crystallized to a pyrophosphate product (predominantly K(2)CaP(2)O(7) and Ca(2)P(2)O(7)). The consequences of the results for the formation of HA materials and devices by the glass conversion route are discussed.

  12. Adsorption of lead ions from aqueous solution using porous carbon derived from rubber tires: experimental and computational study.

    Science.gov (United States)

    Saleh, Tawfik A; Gupta, Vinod K; Al-Saadi, Abdulaziz A

    2013-04-15

    Effective activated porous carbon (AC) was prepared by thermal treatment of waste rubber tires and was further activated using oxidizing agents like nitric acid and hydrogen peroxide. The tire-derived porous carbon was characterized by means of FTIR and X-ray diffraction. Careful analysis of the IR spectra of the synthesized AC reveals a number of bands centered at about 3400, 2350, 1710, 1650, and 1300-1000cm(-1), proving the existence of hydroxyl and carboxylic groups on the surface of AC in addition to CC double bonds. The developed AC was tested and evaluated as a potential adsorbent for the removal of lead (II) ions. Experimental parameters, such as contact time, initial concentration, adsorbent dosage, and pH were optimized. AC was effective in a pH range between 4 and 7 with a highest uptake of lead ions at pH 5 and 6. For further understanding of the chemistry behind the process, density functional theory (DFT) calculations were performed at the B3LYP/6-31G(d) level adopting a functionalized pyrene molecule as a model. The binding energy of Pb(II) ion toward carboxylic acid, carbonyl, and hydroxyl groups was calculated. A binding energy in the range of 310-340kcal/mol, which is considered to be high and to be indicative of a chemisorptions process, was predicted. The adsorption of the lead ion toward the CO groups in relatively all cases shows more stable binding compared to the sorption toward the alcohol groups.

  13. Validated Test Method 5030C: Purge-and-Trap for Aqueous Samples

    Science.gov (United States)

    This method describes a purge-and-trap procedure for the analysis of volatile organic compoundsin aqueous samples & water miscible liquid samples. It also describes the analysis of high concentration soil and waste sample extracts prepared in Method 5035.

  14. Evaluation of zeolite A for the sorptive removal of Cs+ and Sr2+ ions from aqueous solutions using batch and fixed bed column operations.

    Science.gov (United States)

    El-Kamash, A M

    2008-03-01

    Zeolite A was chemically synthesized and evaluated, as inorganic ion exchange material, for the removal of cesium and strontium ions from aqueous solutions in both batch and fixed bed column operations. Batch experiments were carried out as a function of pH, initial ion concentration and temperature. Simple kinetic and thermodynamic models have been applied to the rate and isotherm sorption data and the relevant kinetic and thermodynamic parameters were determined from the graphical presentation of these models. Breakthrough data were determined in a fixed bed column at room temperature (298 K) under the effect of various process parameters like bed depth, flow rate and initial ion concentration. The results showed that the total metal ion uptake and the overall bed capacity decreased with increasing flow rate and increased with increasing initial ion concentrations and bed depth. The dynamics of the ion exchange process was modeled by bed depth service time (BDST) model. The sorption rate constants (K) were found to increase with increase in flow rate indicating that the overall system kinetics was dominated by external mass transfer in the initial part of the sorption process in the column.

  15. Heavy-Ion Radiation Impact on a 4Mb FRAM under Different Test Conditions

    CERN Document Server

    Gupta, V.; Tsiligiannis, G.; Zadeh, A.; Javanainen, A.; Virtanen, A.; Puchner, H.; Saigne, F.; Wrobel, F.; Dilillo, L.

    2015-01-01

    The impact of heavy-ions on commercial Ferroelectric Memories (FRAMs) is analyzed. The influence of different test modes (static and dynamic) on this memory is investigated. Static test results show that the memory is prone to temporary effects occurring in the peripheral circuitry. Dynamic tests results show a high sensitivity of this memory to heavy-ions.

  16. Preliminary Tests Of The Decris-sc Ion Source

    CERN Document Server

    Efremov, A; Bechterev, V; Bogomolov, S L; Bondarenko, P G; Datskov, V I; Dmitriev, S; Drobin, V; Lebedev, A; Leporis, M; Malinowski, H; Nikiforov, A; Paschenko, S V; Seleznev, V; Shishov, Yu A; Smirnov, Yu; Tsvineva, G; Yakovlev, B; Yazvitsky, N Yu

    2004-01-01

    A new "liquid He-free" superconducting Electron Cyclotron Resonance Ion Source DECRIS-SC, to be used as injector for the IC-100 small cyclotron, has been designed by FLNR and LHE JINR. The main feature is that a compact refrigerator of Gifford-McMahon type is used to cool the solenoid coils. For the reason of very small cooling power at 4.2 K (about 1 W) our efforts were to optimize the magnetic structure and minimize an external heating of the coils. The maximum magnetic field strength is 3 T and 2 T in injection and extraction region respectively. For the radial plasma confinement a hexapole made of NdFeB permanent magnet is used. The source will be capable of ECR plasma heating using different frequencies (14 GHz or 18 GHz). To be able to deliver usable intensities of solids, the design is also allow axial access for evaporation oven and metal samples using the plasma sputtering technique. Very preliminary results of the source test are presented.

  17. Production of a fluorescence probe in ion-beam radiolysis of aqueous coumarin-3-carboxylic acid solution-2: Effects of nuclear fragmentation and its simulation with PHITS

    Energy Technology Data Exchange (ETDEWEB)

    Maeyama, Takuya [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Yamashita, Shinichi; Taguchi, Mitsumasa [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Baldacchino, Gerard [CEA Saclay, IRAMIS, UMR 3299 CEA-CNRS SIS2M, Laboratoire de Radiolyse, F-91191 Gif sur Yvette Cedex (France); Sihver, Lembit [Department of Physics, University of Houston, Houston, TX 77204-5005 (United States); Department of Nuclear Engineering, Texas A and M University, TX 77843-3133 (United States); Department of Roanoke College, Salem, VA 24153 (United States); Department of Nuclear Engineering, Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Murakami, Takeshi [Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Katsumura, Yosuke, E-mail: katsu@n.t.u-tokyo.ac.jp [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Nuclear Professional School, School of Engineering, University of Tokyo, 2-22 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki 319-1188 (Japan)

    2011-12-15

    The G(OH) values in aqueous coumarin-3-carboxylic-acid (3-CCA) solutions irradiated with {sup 12}C{sup 6+} beams having the energies of 135, 290 and 400 MeV/u were measured by a fluorescent method around the Bragg peak, with 0.6 mm intervals, and quartz cells of 1 cm optical lengths, at the Heavy Ion Medical Accelerator in Chiba, National Institute of Radiological Sciences (NIRS). For each ion, the G(OH) has been calculated as a function of dose average LET and position. The calculated results have been compared to measurements, and the results, reproducibility and reliability of the calculations are discussed in the paper. - Highlights: > Therapeutic ion beam has energy of several hundred MeV/u because it is necessary for a few tens cm range. > With such high energy, nuclear fragmentations of carbon ions occur resulting in production of lighter ions. > In this study, OH yield in water radiolysis near the Bragg peak of therapeutic ion beams was measured. > Measured yields are discussed considering nuclear fragmentation by PHITS code.

  18. Removal of Cs ions from aqueous solutions by using matrices of natural clinoptilolite and its safe disposal

    Directory of Open Access Journals (Sweden)

    Omerašević Mia

    2016-01-01

    Full Text Available The possibility to use natural zeolite - clinoptilolite as a host material for radioactive Cs immobilization has been investigated. Cs-exchanged form of clinoptilolite which was prepared by treatment of clinoptilolite powder with 0.25 M CsCl solution was compacted. Both, powder and powder compact of exchanged clinoptilolite were thermally treated at 1200°C. The XRPD analysis showed that Cs was successfully immobilized after heat treatment by formation of stable cesium dodecaoxo-alumopentasilicate in both, powder sample and compact. The newly formed compound showed satisfactory Cs ions retention during leaching test. The sintered compact showed somewhat better resistance to Cs leaching than the thermally treated powder. The compressive strength of sintered compact was close to 200 MPa which is more than enough for easy handling and safe storage. [Projekat Ministarstva nauke Republike Srbije, br. 45012

  19. Removal of the metal ions from aqueous solutions by nanoscaled low molecular pectin isolated from seagrass Phyllospadix iwatensis.

    Science.gov (United States)

    Khozhaenko, Elena; Kovalev, Valeri; Podkorytova, Elena; Khotimchenko, Maksim

    2016-09-15

    Pectins from sea grasses are considered as promising substances with pronounced metal-binding activity. Due to the high molecular weight and heterogeneous structure, the use of pectins for removal of metal ions is difficult. Technology of directed pectin degradation was developed and homogenous degraded nanoscaled pectin polymers were synthesized. Experimental samples of degraded pectin isolated from Phyllospadix iwatensis were tested for their metal binding activity in comparison with native pectin from this seagrass and commercial citrus pectin. The metal uptake of all pectin compounds was highest within the pH range from 4.0 to 6.0. The Langmuir, Freundlich and BET sorption models were applied to describe the isotherms and constants. Results showed that depolymerized pectin exerts highest lead and cadmium binding activity with pronounced affinity. All pectin compounds were suggested to be favorable sorbents. Therefore, it can be concluded that degraded pectin is a prospective material for creation of metal-removing water treatment systems.

  20. Ion irradiation testing of Improved Accident Tolerant Cladding Materials

    Energy Technology Data Exchange (ETDEWEB)

    Anderoglu, Osman [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tesmer, Joseph R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Maloy, Stuart A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-14

    This report summarizes the results of ion irradiations conducted on two FeCrAl alloys (named as ORNL A&B) for improving the accident tolerance of LWR nuclear fuel cladding. After irradiation with 1.5 MeV protons to ~0.5 to ~1 dpa and 300°C nanoindentations were performed on the cross-sections along the ion range. An increase in hardness was observed in both alloys. Microstructural analysis shows radiation induced defects.

  1. Thermodynamic studies of aqueous solutions of 2,2,2-cryptand at 298.15 K: enthalpy-entropy compensation, partial entropies, and complexation with K+ ions.

    Science.gov (United States)

    Shaikh, Vasim R; Terdale, Santosh S; Ahamad, Abdul; Gupta, Gaurav R; Dagade, Dilip H; Hundiwale, Dilip G; Patil, Kesharsingh J

    2013-12-19

    The osmotic coefficient measurements for binary aqueous solutions of 2,2,2-cryptand (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8] hexacosane) in the concentration range of ~0.009 to ~0.24 mol·kg(-1) and in ternary aqueous solutions containing a fixed concentration of 2,2,2-cryptand of ~0.1 mol·kg(-1) with varying concentration of KBr (~0.06 to ~0.16 mol·kg(-1)) have been reported at 298.15 K. The diamine gets hydrolyzed in aqueous solutions and needs proper approach to obtain meaningful thermodynamic properties. The measured osmotic coefficient values are corrected for hydrolysis and are used to determine the solvent activity and mean ionic activity coefficients of solute as a function of concentration. Strong ion-pair formation is observed, and the ion-pair dissociation constant for the species [CrptH](+)[OH(-)] is reported. The excess and mixing thermodynamic properties (Gibbs free energy, enthalpy, and entropy changes) have been obtained using the activity data from this study and the heat data reported in the literature. Further, the data are utilized to compute the partial molal entropies of solvent and solute at finite as well as infinite dilution of 2,2,2-cryptand in water. The concentration dependent non-linear enthalpy-entropy compensation effect has been observed for the studied system, and the compensation temperature along with entropic parameter are reported. Using solute activity coefficient data in ternary solutions, the transfer Gibbs free energies for transfer of the cryptand from water to aqueous KBr as well as transfer of KBr from water to aqueous cryptand were obtained and utilized to obtain the salting constant (ks) and thermodynamic equilibrium constant (log K) values for the complex (2,2,2-cryptand:K(+)) at 298.15 K. The value of log K = 5.8 ± 0.1 obtained in this work is found to be in good agreement with that reported by Lehn and Sauvage. The standard molar entropy for complexation is also estimated for the 2,2,2-cryptand

  2. Cost effective and shape controlled approach to synthesize hierarchically assembled NiO nanoflakes for the removal of toxic heavy metal ions in aqueous solution

    Indian Academy of Sciences (India)

    K Yogesh Kumar; H B Muralidhara; Y Arthoba Nayaka; H Hanumanthappa; M S Veena; S R Kiran Kumar

    2015-02-01

    Hierarchical mesoporous NiO nanoflakes (NiOs) have been synthesized in high yield via a simple, economical and environmentally friendly hydrothermal route. The as-prepared NiOs were characterized by powder X-ray diffraction (PXRD), scanning electronicmicroscopy (SEM), transmission electronmicroscopy (TEM), selected area electron diffraction patterns (SAED), X-ray energy dispersive spectroscopy (EDS) and nitrogen adsorption–desorption techniques (Brunauer–Emmett–Teller, BET). Adsorption of heavy metal ions onto the as-prepared sample from aqueous solutions was investigated using differential pulse anodic stripping voltametry (DPASV) technique and discussed. The product possesses a BET surface area of 69.27 m2 g-1. It is found that NiOs exhibited the excellent performance for the removal of Hg(II), Pb(II) and Cd(II) from aqueous solution. The equilibrium adsorption data of Hg(II), Pb(II) and Cd(II) on the as-prepared NiOs were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data. The adsorption capacities for removal of Hg(II), Pb(II) and Cd(II) were determined using the Langmuir equation and found to be 1324.5, 1428.9 and 1428.5 mg g-1, respectively. Adsorption kinetics of all the metal ions followed pseudo second-order model. Moreover, NiOs can be recycled by simple acid treatment, which could retain the high removal efficiency in three successive cycles. This study suggests that nanoflakes could be explored as a new adsorbent with high efficiency and recyclability for removing heavy metal ions from aqueous solution.

  3. Efficient biosorption of lead(II) and cadmium(II) ions from aqueous solutions by functionalized cell with intracellular CaCO3 mineral scaffolds.

    Science.gov (United States)

    Ma, Xiaoming; Cui, Weigang; Yang, Lin; Yang, Yuanyuan; Chen, Huifeng; Wang, Kui

    2015-06-01

    The functionalized Saccharomyces cerevisiae cell with biogenic intracellular CaCO3 mineral scaffold, synthesized via a simple and environmentally friendly approach, was efficient for removing lead (II) and cadmium (II) ions from aqueous solutions. The CaCO3 mineral scaffold could promote the uptake of the heavy metal ions and increase the biosorption capabilities of the adsorbent. Compared with the Freundlich isotherm, Langmuir model more fitted the equilibrium data. The maximum removal capacity of functionalized cells for Pb(II) and Cd(II) was 116.69 and 42.63mgg(-1), respectively. Further investigation showed that the adsorbent had high removal efficiency for trace amount of heavy metal ions. Adsorption data were modeled using the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetics equations. The results indicated that pseudo-second-order kinetic equation and intra-particle diffusion model could better describe the adsorption kinetics. The heavy metal ions might be removed by functionalized cells via membrane transport of metal ions and precipitation transformation.

  4. Adsorption isotherms, kinetics, thermodynamics and desorption studies for uranium and thorium ions from aqueous solution by novel microporous composite P(HEMA-EP)

    Energy Technology Data Exchange (ETDEWEB)

    Akkaya, Recep, E-mail: rakkaya@cumhuriyet.edu.tr [Cumhuriyet University, Vocational School of Health Services, 58140 Sivas (Turkey); Akkaya, Birnur [Cumhuriyet University, Faculty of Science, Department of Molecular Biology and Genetics, 58140 Sivas (Turkey)

    2013-03-15

    Abstract: In this research, a novel composite, poly(2-hydroxyethylmethacrylate-expanded perlite) [P(HEMA-EP)], was synthesized and its adsorptive features were investigated. P(HEMA-EP)’s adsorptive features were evaluated for UO{sub 2}{sup 2+} and Th{sup 4+} ions in terms of the dependency upon the ion concentration, pH, temperature, and time. P(HEMA-EP) was able to bind UO{sub 2}{sup 2+} and Th{sup 4+} ions with strong chemical affinity. The adsorption results were fitted to the classical Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) sorption models. P(HEMA-EP) was also used to study the removal of UO{sub 2}{sup 2+} and Th{sup 4+} ions from aqueous solutions in a batch system. The adsorption capacity (X{sub L}) of UO{sub 2}{sup 2+} and Th{sup 4+} ions was found to be 0.29 and 0.44 mol kg{sup −1}, respectively. The kinetic data corresponds well to the pseudo-second-order equation. Changes in the enthalpy and entropy values demonstrated that the overall adsorption process was spontaneous (ΔG < 0), endothermic (ΔH > 0), and had increased entropy (ΔS > 0), as expected. The reusability of the composites was confirmed for five sequential reuses.

  5. Sulfonated Magnetic Nanocomposite Based on Reactive PGMA-MAn Copolymer@Fe3O4 Nanoparticles: Effective Removal of Cu(II Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Reza Hasanzadeh

    2016-01-01

    Full Text Available Chelating magnetic nanocomposites have been considered as suitable materials for removal of heavy metal ions for water treatment. In this work poly(glycidyl methacrylate-maleic anhydride copolymer (PGMA-MAn is modified with 4-aminobenzenesulfonic acid (ABSAc and subsequently the product reacted with modified Fe3O4 nanoparticles and 1,2-ethanedithiol (EDT in the presence of ultrasonic irradiation for preparation of tridimensional chelating magnetic nanocomposite. Synthesized magnetic nanocomposite was characterized by Fourier transform infrared spectroscopy (FT-IR, scanning electron microscopy (SEM, X-ray diffraction analysis (XRD, vibrating sample magnetometer (VSM, energy dispersive X-ray analysis (EDX, elemental mapping analysis (EMA, Brunauer-Emmett-Teller (BET, and thermal gravimetric analysis (TGA. The adsorption behavior of Cu(II ions was investigated by synthesized nanocomposite in various parameters such as pH, contact time, metal ion concentration, and adsorbent dosage. The equilibrium distribution coefficient (kd was determined and the findings prove that the kd value is approximately high in the case of all selected metal ions. The synthesized nanocomposite exhibited good tendency for removing Cu(II ions from aqueous solutions even at an acidic pH.

  6. Measurement of Uncertainty for Aqueous Ethanol Wet-Bath Simulator Solutions Used with Evidential Breath Testing Instruments.

    Science.gov (United States)

    Hwang, Rong-Jen; Beltran, Jada; Rogers, Craig; Barlow, Jeremy; Razatos, Gerasimos

    2016-09-01

    Aqueous ethanol wet-bath simulator solutions are used to perform calibration adjustments, calibration checks, proficiency testing, and inspection of breath alcohol instruments. The Toxicology Bureau of the New Mexico Department of Health has conducted a study to estimate a measurement of uncertainty for the preparation and testing of these wet-bath simulator solutions. The measurand is identified as the mass concentration of ethanol (g/100 mL) determined through dual capillary column headspace gas chromatography with flame ionization detector analysis. Three groups were used in the estimation of the aqueous ethanol wet-bath simulator solutions uncertainty: GC calibration adjustment, GC analytical, and certified reference material. The standard uncertainties for these uncertainty sources were combined using the method of root-sum-squares to give uc = 0.8598%. The combined standard uncertainty was expanded to U = 1.7% to reflect a confidence level of 95% using a coverage factor of 2. This estimation applies to all aqueous ethanol wet-bath simulator solution concentrations produced by this laboratory.

  7. Utilization of various agricultural wastes for activated carbon preparation and application for the removal of dyes and metal ions from aqueous solutions.

    Science.gov (United States)

    Kadirvelu, K; Kavipriya, M; Karthika, C; Radhika, M; Vennilamani, N; Pattabhi, S

    2003-03-01

    Activated carbons were prepared from the agricultural solid wastes, silk cotton hull, coconut tree sawdust, sago waste, maize cob and banana pith and used to eliminate heavy metals and dyes from aqueous solution. Adsorption of all dyes and metal ions required a very short time and gave quantitative removal. Experimental results show all carbons were effective for the removal of pollutants from water. Since all agricultural solid wastes used in this investigation are freely, abundantly and locally available, the resulting carbons are expected to be economically viable for wastewater treatment.

  8. Aspects on the catalysis of lipase from porcine pancreas (type VI-s) in aqueous media: development of ion-pairs

    OpenAIRE

    2012-01-01

    This article reports a first contribution for the elucidation of catalytic mechanism of Lipase from porcine pancreas, type VI-s (PPL), in hydrolyzing an ester substrate in aqueous media. The conclusions were based on the pH-profiles of Michaelis-Menten parameters k cat/Km, k cat and Km, as well as on the absolute temperature profile of k cat/Km, obtained during the hydrolysis of p-nitrophenyl laurate by PPL. It was found that (a) PPL performs catalysis by means of ion pairs formed either as S...

  9. The Influence of the Anionic Counter-Ion on the Activity of Ammonium Substituted Hoveyda-Type Olefin Metathesis Catalysts in Aqueous Media

    Science.gov (United States)

    Gułajski, Łukasz; Grela, Karol

    Polar olefin metathesis catalysts, bearing an ammonium group are presented. The electron withdrawing ammonium group not only activates the catalysts electronically, but at the same time makes the catalysts more hydrophilic. Catalysts can be therefore efficiently used not only in traditional media, such as methylene chloride and toluene, but also in technical-grade alcohols, alcohol— water mixtures and in neat water. Finally, in this overview the influence of the anionic counter-ion on the activity of ammonium substituted Hoveyda-type olefin metathesis catalysts in aqueous media is presented.

  10. Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal recovery from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fish, R.H.

    1998-11-10

    The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1--3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe{sup 3+}, Al{sup 3+} ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads used determined are useful as well as equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe{sup 3+} ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2,6-LICAMS series of polymer pendant ligands are more selective to divalent metal ions Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, and Mg{sup 2+}, than either PS-CATS or PS-3,3-LICAMS. However, Fe{sup 3+} ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe{sup 3+}, the polymer ligand is selective for Al{sup 3+}, Cu{sup 2+} or Hg{sup 2+}. The changing of the cavity size from two CH{sub 2} groups to six CH{sub 2} groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect

  11. Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal recovery from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fish, Richard H. (Berkeley, CA)

    1998-01-01

    The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe.sup.3+ ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+, Mg.sup.2+, Al.sup.3+, and Cr.sup.3+ ions at pH 1-3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe.sup.3+ (for example, Hg.sup.2+ at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe.sup.3+ Al.sup.3+ ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads used determined are useful as well as equilibrium selectivity coefficient (K.sub.m) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe.sup.3+ ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2,6-LICAMS series of polymer pendant ligands are more selective to divalent metal ions Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+, and Mg.sup.2+, than either PS-CATS or PS-3,3-LICAMS. However, Fe.sup.3+ ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe.sup.3+, the polymer ligand is selective for Al.sup.3+, Cu.sup.2+ or Hg.sup.2+. The changing of the cavity size from two CH.sub.2 groups to six CH.sub.2 groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion

  12. Fuel Cell Stack Testing and Durability in Support of Ion Tiger UAV

    Science.gov (United States)

    2010-06-02

    This report covers efforts by the Hawaii Natural Energy Institute (HNEI) of the University of Hawaii under the ONR-funded Ion Tiger UAV award that included testing of Ion Tiger fuel cell stacks in HNEI’s Hawaii Fuel Cell Test Facility located in Honolulu, Hawaii. Work was focused on steady-state stack characteristics of Protonex fuel cell stacks under various operating conditions. In addition, Hardware-in-the-Loop testing was performed to characterize dynamic

  13. Development of Monopole Interaction Models for Ionic Compounds. Part I: Estimation of Aqueous Henry's Law Constants for Ions and Gas Phase pKa Values for Acidic Compounds.

    Science.gov (United States)

    Hilal, S H; Saravanaraj, A N; Carreira, L A

    2014-02-01

    The SPARC (SPARC Performs Automated Reasoning in Chemistry) physicochemical mechanistic models for neutral compounds have been extended to estimate Henry's Law Constant (HLC) for charged species by incorporating ionic electrostatic interaction models. Combinations of absolute aqueous pKa values, relative pKa values in the gas phase, and aqueous HLC for neutral compounds have been used to develop monopole interaction models that quantify the energy differences upon moving an ionic solute molecule from the gas phase to the liquid phase. Inter-molecular interaction energies were factored into mechanistic contributions of monopoles with polarizability, dipole, H-bonding, and resonance. The monopole ionic models were validated by a wide range of measured gas phase pKa data for 450 acidic compounds. The RMS deviation error and R(2) for the OH, SH, CO2 H, CH3 and NR2 acidic reaction centers (C) were 16.9 kcal/mol and 0.87, respectively. The calculated HLCs of ions were compared to the HLCs of 142 ions calculated by quantum mechanics. Effects of inter-molecular interaction of the monopoles with polarizability, dipole, H-bonding, and resonance on acidity of the solutes in the gas phase are discussed.

  14. Effect of copper ions on the degradation of thiram in aqueous solution: identification of degradation products by HPLC-MS/MS.

    Science.gov (United States)

    Filipe, Olga M S; Santos, Sónia A O; Domingues, M Rosário M; Vidal, Maria M; Silvestre, Armando J D; Santos, Eduarda B H

    2014-08-30

    The aim of this work was to examine the effect of Cu(II) on the degradation of thiram (Thi) in aqueous solutions, since the literature focused on this effect is scarce and copper based fungicides can be applied together with thiram or during the same season to agricultural crops. The effect of Cu(II) on the degradation of thiram was followed by both UV-vis and HPLC-MS/MS. When thiram is dissolved in pure water its degradation occurs very slowly, being negligible during the first 7 days. However, the presence of Cu(II) has a strong influence on the thiram degradation in aqueous solutions along time. In the presence of an excess of Cu(II), a [CuThi](2+) complex is initially formed which degrades into a complex formed between the dimethyldithiocarbamate anion (DMDTC) and Cu(II) ion, [Cu(DMDTC)](+). This complex further degrades leading to other copper complexes which were identified for the first time, by MS(n). The results obtained in the present work also demonstrated that a redox reaction involving DMDTC anions and Cu(II) ions gives rise to the formation of a Thi-Cu(I) complex. Finally, some of the complexes resulting from the degradation of [CuThi](2+) are quite persistent in solution for long periods of time (>1 month).

  15. Synthesis of aqueous suspensions of magnetic nanoparticles with the co-precipitation of iron ions in the presence of aspartic acid

    Science.gov (United States)

    Pušnik, Klementina; Goršak, Tanja; Drofenik, Miha; Makovec, Darko

    2016-09-01

    There is increasing demand for the production of large quantities of aqueous suspensions of magnetic iron-oxide nanoparticles. Amino acids are one possible type of inexpensive, nontoxic, and biocompatible molecules that can be used as the surfactants for the preparation of stable suspensions. This preparation can be conducted in a simple, one-step process based on the co-precipitation of Fe3+/Fe2+ ions in the presence of the amino acid. However, the presence of this amino acid changes the mechanism of the magnetic nanoparticles' formation. In this investigation we analyzed the influence of aspartic amino acid (Asp) on the formation of magnetic iron-oxide nanoparticles during the co-precipitation. The process of the nanoparticles' formation was followed using a combination of TEM, x-ray diffractometry, magnetic measurements, in-situ FT-IR spectroscopy, and chemical analysis, and compared with the formation of nanoparticles without the Asp. The Asp forms a coordination complex with the Fe3+ ions, which impedes the formation of the intermediate iron oxyhydroxide phase and suppresses the growth of the final magnetic iron-oxide nanoparticles. Slower reaction kinetics can lead to the formation of nonmagnetic secondary phases. The aspartic-acid-absorbed nanoparticles can be dispersed to form relatively concentrated aqueous suspensions displaying a good colloidal stability at an increased pH.

  16. Tailor-made micro-object optical sensor based on mesoporous pellets for visual monitoring and removal of toxic metal ions from aqueous media.

    Science.gov (United States)

    El-Safty, Sherif A; Shenashen, M A; Shahat, A

    2013-07-08

    Methods for the continuous monitoring and removal of ultra-trace levels of toxic inorganic species (e.g., mercury, copper, and cadmium ions) from aqueous media such as drinking water and biological fluids are essential. In this paper, the design and engineering of a simple, pH-dependent, micro-object optical sensor is described based on mesoporous aluminosilica pellets with an adsorbed dressing receptor (a porphyrinic chelating ligand). This tailor-made optical sensor permits ultra-fast (≤ 60 s), specific, pH-dependent visualization and removal of Cu(2+) , Cd(2+) , and Hg(2+) at sub-picomolar concentrations (∼10(-11) mol dm(-3) ) from aqueous media, including drinking water and a suspension of red blood cells. The acidic active acid sites of the pellets consist of heteroatoms arranged around uniformly shaped pores in 3D nanoscale gyroidal mesostructures densely coated with the chelating ligand. The sensor can be used in batch mode, as well as in a flow-through system in which sampling, target ion recognition and removal, and analysis are integrated in a highly automated and efficient manner. Because the pellets exhibit long-term stability, reproducibility, and versatility over a number of analysis/regeneration cycles, they can be expected to be useful for the fabrication of inexpensive sensor devices for naked-eye detection of toxic pollutants.

  17. Cowpea pod (Vigna unguiculata) biomass as a low-cost biosorbent for removal of Pb(II) ions from aqueous solution.

    Science.gov (United States)

    Guyo, U; Moyo, M

    2017-01-01

    The use of cowpea pod (CPP) biomass for the removal of Pb(II) ions from aqueous solution was investigated. The effects of factors such as dosage concentration (0.2 to 1.6 g L(-1)), pH (2 to 8), contact time (5 to 120 min), metal ion concentrations (10 to 80 mg L(-1)) and temperature (20 to 50 °C) were examined through batch studies. The biosorption data conformed best to the Langmuir model at the three working temperatures (20, 30 and 40 °C) as revealed by the correlation coefficients (R (2)) which were greater than 0.940. The maximum sorption capacity of the CPP for Pb(II) was 32.96 mg g(-1) at 313 K. Furthermore, the kinetic data fitted well to the pseudo-second-order model as it had the lowest sum of square error (SSE) values and correlation coefficients close to unity (R (2) > 0.999). The thermodynamic parameters (ΔG°, ΔS° and ΔH°) showed that the biosorption process was spontaneous, feasible and endothermic. The results obtained in the present study indicated that cowpea pod biomass could be used for the effective removal of Pb(II) from aqueous solution.

  18. Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal and recovery from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fish, Richard H. (Berkeley, CA)

    1997-01-01

    The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe.sup.3+ ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu.sup.2+, Zn.sup.2+, Mn.sup.2+, Ni.sup.2+,Mg.sup.2+, Al.sup.3+, and Cr.sup.3+ ions at pH 1-3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe.sup.3+ (for example, Hg.sup.2+ at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe.sup.3+ Al.sup.3+ ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads use determined are useful as well as equilibrium selectivity coefficient (K.sub.m) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe.sup.3+ ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2-6-Mn.sup.2+, Ni.sup.2+, and Mg.sup.2+, than either PS-CATS or PS-3,3-LICAMS. However, Fe.sup.3+ ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe.sup.3+, the polymer ligand is selective for Al.sup.3+, Cu.sup.2+ or Hg.sup.2+. The changing of the cavity size from two CH.sub.2 groups to six CH.sub.2 groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion selectivity.

  19. Polymer-supported sulfonated catechol and linear catechol amide ligands and their use in selective metal ion removal and recovery from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fish, R.H.

    1997-04-22

    The present invention concerns the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis-catechol linear amide (PS-2-6-LICAMS) and sulfonated 3,3-linear tris-catechol amide (PS-3,3-LICAMS) ligands, which chemically bond to modified 6% crosslinked macroporous polystyrene-divinylbenzene beads (PS-DVB). These polymers are useful for the for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity shown for PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1--3. Further, the metal ion selectivity is changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). The rates of selective removal and recovery of the trivalent metal ions, e.g. Fe{sup 3+}, Al{sup 3+} ion etc. with the PS-CATS, PS-2-6-LICAMS, and PS-3,3-LICAMS polymer beads use determined are useful as well as equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies. The chelate effect for the predisposed octahedral PS-3,3-LICAMS polymer pendant ligand is the reason that this ligand has a more pronounced selectivity for Fe{sup 3+} ion in comparison to the PS-CATS polymer beads. The predisposed square planar PS-2-6-Mn{sup 2+}, Ni{sup 2+}, and Mg{sup 2+}, than either PS-CATS or PS-3,3-LICAMS. However, Fe{sup 3+} ion still dominates in competition with other divalent and trivalent metal ions. In the absence of Fe{sup 3+}, the polymer ligand is selective for Al{sup 3+}, Cu{sup 2+} or Hg{sup 2+}. The changing of the cavity size from two CH{sub 2} groups to six CH{sub 2} groups in the PS-2-6-LICAMS polymer pendant ligand series does not effect the order of metal ion selectivity. 9 figs.

  20. Removal of Pb(II) ions from aqueous solution using water hyacinth root by fixed-bed column and ANN modeling.

    Science.gov (United States)

    Mitra, Tania; Singha, Biswajit; Bar, Nirjhar; Das, Sudip Kumar

    2014-05-30

    Hyacinth root was used as a biosorbent for generating adsorption data in fixed-bed glass column. The influence of different operating parameters like inlet Pb(II) ion concentration, liquid flow rate and bed height on the breakthrough curves and the performance of the column was studied. The result showed that the adsorption efficiency increased with increase in bed height and decreased with increase in inlet Pb(II) ion concentration and flow rate. Increasing the flow rate resulted in shorter time for bed saturation. The result showed that as the bed height increased the availability of more number of adsorption sites in the bed increased, hence the throughput volume of the aqueous solution also increased. The adsorption kinetics was analyzed using different models. It was observed that maximum adsorption capacity increased with increase in flow rate and initial Pb(II) ion concentration but decreased with increase in bed height. Applicability of artificial neural network (ANN) modeling for the prediction of Pb(II) ion removal was also reported by using multilayer perceptron with backpropagation, Levenberg-Marquardt and scaled conjugate algorithms and four different transfer functions in a hidden layer and a linear output transfer function.

  1. Adsorption Behaviour of La(III and Eu(III Ions from Aqueous Solutions by Hydroxyapatite: Kinetic, Isotherm, and Thermodynamic Studies

    Directory of Open Access Journals (Sweden)

    F. Granados-Correa

    2013-01-01

    Full Text Available The hydroxyapatite was successfully synthesized, characterized, and used as an alternative low-cost adsorbent material to study the adsorption behavior of La(III and Eu(III ions from nitrate aqueous solutions as a function of contact time, initial metal ion concentration, pH, and temperature by using a bath technique. The kinetic data correspond very well to the pseudo-second-order equation, and in both cases the uptake was affected by intraparticle diffusion. Isotherm adsorption data were well fitted by the Freundlich model equation with 1/n>1, indicating a multilayer and cooperative-type adsorption. Thermodynamic parameters for the adsorption systems were determinated at 293, 303, 313, and 323 K. These parameters show that adsorptions of La(III and Eu(III ions on hydroxyapatite are endothermic and spontaneous processes. The adsorption was found to follow the order Eu(III > La(III and is dependent on ion concentration, pH, and temperature.

  2. Production of a fluorescence probe in ion-beam radiolysis of aqueous coumarin-3-carboxylic acid solution-1: Beam quality and concentration dependences

    Science.gov (United States)

    Maeyama, Takuya; Yamashita, Shinichi; Baldacchino, Gérard; Taguchi, Mitsumasa; Kimura, Atsushi; Murakami, Takeshi; Katsumura, Yosuke

    2011-04-01

    Aqueous coumarin-3-carboxylic acid (3-CCA) solutions were irradiated with seven different ion beams covering LET range from 0.5 to above 2000 eV/nm. G-values of 7OH-CCA, one of hydroxylated products in radiolysis of the solutions, have been determined by fluorescence-HPLC technique in 3-CCA concentration range from 0.1 to 26 mM. The formation yield of 7OH-CCA increased with increase in concentration of 3-CCA while it decreased with increase in LET value of ion beam. Compared with our previous reports on G(•OH) at a scavenging capacity of 107 s-1 with absorption spectroscopy, it was found that G(7OH-CCA) is about (4.7±0.6)% of G(•OH), which is consistent for all of the ion beams used in the present study. However, 7OH-CCA yields in high 3-CCA concentration region, especially by using extremely high LET ions, were much higher than expected values based on the above conversion factor and G(•OH) value predicted in theoretical work.

  3. The role of Stern layer in the interplay of dielectric saturation and ion steric effects for the capacitance of graphene in aqueous electrolytes

    Science.gov (United States)

    Daniels, Lindsey; Scott, Matthew; Mišković, Z. L.

    2017-03-01

    Nano-scale devices continue to challenge our theoretical understanding of microscopic systems. Of particular interest is the characterization of the interface electrochemistry of graphene-based sensors. Typically operated in a regime of high ion concentration and high surface charge density, dielectric saturation and ion crowding become non-negligible at the interface, complicating continuum treatments based upon the Poisson-Boltzmann equation. Using the Poisson-Boltzmann equation, modified with the Bikerman-Freise model to account for non-zero ion size and the Booth model to account for dielectric saturation at the interface, we characterize the diffuse layer capacitance of both metallic and graphene electrodes immersed in an aqueous electrolyte. We find that the diffuse layer capacitance exhibits two peaks when the surface charge density of the electrode is increased, in contrast with experimental results. We propose a self-consistent (and parameter-free) method to include the Stern layer which eliminates the spurious secondary peak in the capacitance and restores the correspondence of the model with experimental observations. This study sheds light on the interplay between the ion steric effects and the dielectric saturation in solvent, exposes the importance of quantum capacitance when graphene is used as an electrode, and demonstrates the importance of a self-consistent treatment of the Stern layer in continuum models of the electrode-electrolyte interface. Furthermore, the theoretical foundation provides a base upon which more detailed models of graphene-based sensors can be built.

  4. Production and test of {sup 18}F samples in the SNICS ion source

    Energy Technology Data Exchange (ETDEWEB)

    Rehm, K.E.; Paul, M. [Hebrew Univ., Jerusalem (Israel); Roberts, A.; Nickels, J. [Univ. of Wisconsin, Madison, MO (United States)

    1995-08-01

    For experiments with {sup 18}F beams the output of the SNICS ion source for fluorine ions was investigated. {sup 18}F, which is a well-studied PET isotope, is generated at the medical cyclotron of the University of Wisconsin. Aqueous [{sup 18}F] fluoride ions are produced via the {sup 18}O(p,n){sup 18}F reaction using a 30-{mu}A, 11.4-MeV proton beam bombarding a 95% enriched [{sup 18}O] water target. In order to minimize the {sup 18}O component of the {sup 18}F material the [{sup 18}F] fluoride must be separated from the [{sup 18}O] water. For this purpose the aqueous [{sup 18}F] fluoride solution ({approximately} 0.5-1 ml) is removed from the production target and placed in a glassy carbon vessel. The vessel is heated to 115{degrees}C with He bubbling through the solution, evaporating the water while the {sup 18}F adheres to the vessel walls. When dry, the vessel is filled with 1 ml {sup 18}O-depleted 99.98% [{sup 16}O] water which is again evaporated. After this step is repeated once more the vessel is filled with 1.5 ml [{sup 16}O] water and 200-300 mole of natural KF as carrier material.

  5. Detection of zinc ions under aqueous conditions using chirality assisted solid-state fluorescence of a bipyridyl based fluorophore.

    Science.gov (United States)

    Sreejith, Sivaramapanicker; Divya, Kizhumuri P; Ajayaghosh, Ayyappanpillai

    2008-07-07

    A pyrrole end-capped bipyridyl ligand incorporating a chiral handle exhibited high solid-state emission when compared to the achiral analogue 1b and to the racemic molecule 1c which allowed the design of a reusable fluorescent probe for the selective detection of Zn2+ under aqueous conditions.

  6. Removal of the metal ions from aqueous solutions by nanoscaled low molecular pectin isolated from seagrass Phyllospadix iwatensis

    Energy Technology Data Exchange (ETDEWEB)

    Khozhaenko, Elena [Far Eastern Federal University, School of Biomedicine, 8, Sukhanova str., Vladivostok 690091 (Russian Federation); A.V. Zhirmunsky Institute of Marine Biology Far Eastern Branch of Russian Academy of Sciences, 17, Palchevskgo str., Vladivostok 690059 (Russian Federation); Kovalev, Valeri; Podkorytova, Elena [A.V. Zhirmunsky Institute of Marine Biology Far Eastern Branch of Russian Academy of Sciences, 17, Palchevskgo str., Vladivostok 690059 (Russian Federation); Khotimchenko, Maksim, E-mail: maxkhot@yandex.ru [Far Eastern Federal University, School of Biomedicine, 8, Sukhanova str., Vladivostok 690091 (Russian Federation); A.V. Zhirmunsky Institute of Marine Biology Far Eastern Branch of Russian Academy of Sciences, 17, Palchevskgo str., Vladivostok 690059 (Russian Federation)

    2016-09-15

    Pectins from sea grasses are considered as promising substances with pronounced metal-binding activity. Due to the high molecular weight and heterogeneous structure, the use of pectins for removal of metal ions is difficult. Technology of directed pectin degradation was developed and homogenous degraded nanoscaled pectin polymers were synthesized. Experimental samples of degraded pectin isolated from Phyllospadix iwatensis were tested for their metal binding activity in comparison with native pectin from this seagrass and commercial citrus pectin. The metal uptake of all pectin compounds was highest within the pH range from 4.0 to 6.0. The Langmuir, Freundlich and BET sorption models were applied to describe the isotherms and constants. Results showed that depolymerized pectin exerts highest lead and cadmium binding activity with pronounced affinity. All pectin compounds were suggested to be favorable sorbents. Therefore, it can be concluded that degraded pectin is a prospective material for creation of metal-removing water treatment systems. - Highlights: • Low molecular nanoscaled pectin was obtained using original hydrolysis method • Metal binding activity of pectin compounds was studied in a batch sorption system • Pectins exert highest metal binding activity at pH 6.0 • Metal binding isotherms of all pectins are best described by the Langmuir equation • Low molecular pectin from seagrasses is more effective than high-molecular pectins.

  7. [Adsorption of calcium ion from aqueous solution using Na(+)-conditioned clinoptilolite for hot-water softening].

    Science.gov (United States)

    Zhang, Shuo; Wang, Dong; Chen, Yuan-Chao; Zhang, Xing-Wen; Chen, Gui-Jun

    2015-02-01

    This work investigated adsorptive removal of calcium ion (Ca2+) by virtue of Na(+) -conditioned clinoptilolite simulating the process of softening for industrial hot-water system. Influential factors such as the activation/regeneration of sorbent and solution pH were tested. The kinetics/thermodynamics for adsorption of Ca2+ were analyzed and discussed. Results showed that: (1) The adsorption rate was in good agreement with the pseudo-second order kinetic models, and the process of adsorption better followed the Langmuir model; (2) Higher solution temperature allowed an enhanced efficiency on Ca2+ removal, albeit the maximum adsorption capacity of Na(+)-conditioned clinoptilolite was hardly affected; (3) The process of adsorption was dominated by chemisorption, and also characterized by entropy increase with spontaneous/endothermic nature; (4) Solution temperature was suggested to be controlled within the range of 6 to 10, and more than 9 times of sorbent regeneration could be ensured for an effective adsorption towards Ca2+ with initial concentration less than 20 mg x L(-1). It was demonstrated that the activated clinoptilolite should be a promising alternative adsorbent for industrial hot-water softening.

  8. Analysis of Adsorption, Ion Exchange, Thermodynamic Behaviour of Some Organic Cations on Dowex 50WX4-50/H+ Cation Exchanger in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Ehteram A. Noor

    2011-01-01

    Full Text Available The equilibrium adsorption, ion exchange characteristics of various concentrations of some organic cations from aqueous solutions onto dowex 50WEX/H+ cation exchanger were studied at different temperatures in the range of 30-50 °C. The studied cations showed good adsorptive properties onto dowex 50WX4-5/H+ at different concentrations and temperatures. Main adsorption behaviour was ion exchange between hydrogen ions and the organic cations as indicated from the linear relation between the initial concentration of the organic cations and the released hydrogen ions. It was found that the adsorption affinity of dowex 50WX4-50/H+ towards the studied organic cations depends on the substituent type of the organic cations giving the following increasing order: 1-H < 2-OH < 3-OCH3. Thermodynamic parameters for the adsorption of the studied organic cations were evaluated and discussed. It was found that the adsorption 1-H organic cation was spontaneous, ordered, exothermic and favored with decreasing temperature. On the other hand the adsorption of both 2-OH and 3-OCH3 organic cations was found to be spontaneous and disordered with enthalpy change varies significantly with increasing organic cation concentration, suggesting dipole-dipole adsorption forces as new active sites for adsorption under conditions of relatively high concentrations. Freundlich and Dubinin-Radushkevich adsorption isotherm models reasonably describe the adsorption of the studied organic cations onto dowex 50WX4-50/H+ by segmented straight lines depending on the studied range of concentration, indicating the existence of two different sets of adsorption sites with substantial difference in energy of adsorption. According to Dubinin-Radushkevich adsorption isotherm model, physical-ion exchange mechanism was suggested for the adsorption of 1-H organic cation and both physical and chemical-ion exchange mechanisms were suggested for the adsorption of 2-OH and 3-OCH3 organic cations

  9. A plant-wide aqueous phase chemistry module describing pH variations and ion speciation/pairing in wastewater treatment process models.

    Science.gov (United States)

    Flores-Alsina, Xavier; Kazadi Mbamba, Christian; Solon, Kimberly; Vrecko, Darko; Tait, Stephan; Batstone, Damien J; Jeppsson, Ulf; Gernaey, Krist V

    2015-11-15

    There is a growing interest within the Wastewater Treatment Plant (WWTP) modelling community to correctly describe physico-chemical processes after many years of mainly focusing on biokinetics. Indeed, future modelling needs, such as a plant-wide phosphorus (P) description, require a major, but unavoidable, additional degree of complexity when representing cationic/anionic behaviour in Activated Sludge (AS)/Anaerobic Digestion (AD) systems. In this paper, a plant-wide aqueous phase chemistry module describing pH variations plus ion speciation/pairing is presented and interfaced with industry standard models. The module accounts for extensive consideration of non-ideality, including ion activities instead of molar concentrations and complex ion pairing. The general equilibria are formulated as a set of Differential Algebraic Equations (DAEs) instead of Ordinary Differential Equations (ODEs) in order to reduce the overall stiffness of the system, thereby enhancing simulation speed. Additionally, a multi-dimensional version of the Newton-Raphson algorithm is applied to handle the existing multiple algebraic inter-dependencies. The latter is reinforced with the Simulated Annealing method to increase the robustness of the solver making the system not so dependent of the initial conditions. Simulation results show pH predictions when describing Biological Nutrient Removal (BNR) by the activated sludge models (ASM) 1, 2d and 3 comparing the performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) treatment plant configuration under different anaerobic/anoxic/aerobic conditions. The same framework is implemented in the Benchmark Simulation Model No. 2 (BSM2) version of the Anaerobic Digestion Model No. 1 (ADM1) (WWTP3) as well, predicting pH values at different cationic/anionic loads. In this way, the general applicability/flexibility of the proposed approach is demonstrated, by implementing the aqueous phase chemistry module in some

  10. Combination of ozonation and photocatalysis for purification of aqueous effluents containing formic acid as probe pollutant and bromide ion.

    Science.gov (United States)

    Parrino, F; Camera-Roda, G; Loddo, V; Palmisano, G; Augugliaro, V

    2014-03-01

    The treatment by advanced oxidation processes (AOPs) of waters contaminated by organic pollutants and containing also innocuous bromide ions may generate bromate ions as a co-product. In the present work heterogeneous photocatalysis and ozonation have individually been applied and in combination (integrated process) to degrade the organic compounds in water containing also bromide anions. The results show that: i) the sole photocatalysis does not produce bromate ions and in the case of its presence, it is able to reduce bromate to innocuous bromide ions; ii) the integration of photocatalysis and ozonation synergistically enhances the oxidation capabilities; and iii) in the integrated process bromate ions are not produced as long as some oxidizable organics are present.

  11. Biosorption of Cd(Ⅱ)and Pb(Ⅱ)Ions by Aqueous Solutions of Novel Alkalophillic Streptomyces VITSVK5 spp.Biomass

    Institute of Scientific and Technical Information of China (English)

    Kumar Saurav; Krishnan Kannabiran

    2011-01-01

    Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment.Biosorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution.The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species.The biosorption property of Streptomyces VITSVK5 spp.was investigated by absorbing heavy metals Cadmium(Cd)and Lead(Pb).Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L·1,cadmium 3.1±0.3 μg L·1,zinc 8.4±2.6μg L·1 and copper 0.3±0.1μg L·1,whereas mercury was well below the detection limit.The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated.The optimum pH for maximal biosorption was4.0 for Cd(Ⅱ)and 5.0 for Pb(Ⅱ)with 41% and 84% biosorption respectively.The biosorbent dosage was optimized as 3 g L-1 for both the trace metals.Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl(-COOH),hydroxyl(-CHOH)and amine(-NH2)groups of biomass with the metal ions.This could be mainly involved in the biosorption of Cd(Ⅱ)and Pb(Ⅱ)onto Streptomyces VITSVK5 spp.The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.

  12. Biosorption of Cd(II) and Pb(II) ions by aqueous solutions of novel alkalophillic Streptomyces VITSVK5 spp. biomass

    Science.gov (United States)

    Saurav, Kumar; Kannabiran, Krishnan

    2011-03-01

    Discharge of heavy metals from metal processing industries is known to have adverse effects on the environment. Biosorption of heavy metals by metabolically inactive biomass of microbial organisms is an innovative and alternative technology for removal of these pollutants from aqueous solution. The search of marine actinobacteria with potential heavy metal biosorption ability resulted in the identification of a novel alkalophilic Streptomyces VITSVK5 species. The biosorption property of Streptomyces VITSVK5 spp. was investigated by absorbing heavy metals Cadmium (Cd) and Lead (Pb). Physiochemical characteristics and trace metal concentration analysis of the backwater showed the concentrations of different metals were lead 13±2.1 μg L-1, cadmium 3.1±0.3μg L-1, zinc 8.4±2.6μg L-1 and copper 0.3±0.1μg L-1, whereas mercury was well below the detection limit. The effect of pH and biomass dosage on removal efficiency of heavy metal ions was also investigated. The optimum pH for maximal biosorption was 4.0 for Cd (II) and 5.0 for Pb (II) with 41% and 84% biosorption respectively. The biosorbent dosage was optimized as 3 g L-1 for both the trace metals. Fourier transform infrared absorption spectrum results indicated the chemical interactions of hydrogen atoms in carboxyl (-COOH), hydroxyl (-CHOH) and amine (-NH2) groups of biomass with the metal ions. This could be mainly involved in the biosorption of Cd (II) and Pb (II) onto Streptomyces VITSVK5 spp. The results of our study revealed Streptomyces metabolites could be used to develop a biosorbent for adsorbing metal ions from aqueous environments.

  13. 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.

  14. 纳米羟基磷灰石的镉离子吸附性能%Properties of nano hydroxyapatite for sorption of aqueous cadmium ion

    Institute of Scientific and Technical Information of China (English)

    石和彬; 钟宏; 刘羽; 田兴; 顾金燕; 鲁斌

    2012-01-01

    Nano hydroxyapatite (n - HA) was prepared by a coprecipitation process using calcium nitrate, phosphoric acid and ammonia as raw materials. The aqueous solution of cadmium nitrate was used as simulated waste water, and the solution chemistry of the waste water was illustrated by using Visual MINTEQ software. The effects of the initial pH value of the waste water, reaction time and initial content of Cd2+ on the Cd2+-sorption-capacity of n - HA were tested. The results show that the Cd2+-sorptive property of n - HA changes little at the initial pH value of Cd2+ solution being 4 to 9, the process of Cd2+ sorption on n - HA accords with pseudo-second-order kinetic model and highly fits Langmuir isotherm and Freundlich isotherm. The kinetic and thermal characteristics reflect that ion-exchange is the main mechanism of Cd2+ sorption on n - HA. n - HA is a kind of advanced environmental materials for its great capacity and high initial rate on sorption of aqueous Cd2+.%以硝酸钙、磷酸、氨水为原料,采用共沉淀法合成了纳米羟基磷灰石粉体.以硝酸镉水溶液作为模拟废水,用VisualMINTEQ软件对模拟废水的溶液化学特征进行了计算,主要研究了溶液的初始pH值、反应时间以及镉离子(Cd2+)初始浓度等因素对纳米羟基磷灰石的镉离子吸附量的影响.实验结果表明,纳米羟基磷灰石的镉离子吸附性能在溶液初始pH为4-9的范围内比较稳定,其去除水溶液中镉离子的过程符合准二级动力学模型,并且与朗缪尔等温吸附和弗伦德里希等温吸附均表现出了较高的相关性,反映了纳米羟基磷灰石吸附水溶液中镉离子的反应以离子交换作用为主的特点.纳米羟基磷灰石不仅镉离子吸附容量大,而且初期吸附速率很快,是一种性能良好的环境矿物吸附材料.

  15. Removal of uranium(VI) ions from aqueous solutions using Schiff base functionalized SBA-15 mesoporous silica materials.

    Science.gov (United States)

    Dolatyari, Leila; Yaftian, Mohammad Reza; Rostamnia, Sadegh

    2016-03-15

    Functionalized SBA-15 mesoporous silica particles, bearing N-propylsalicylaldimine and ethylenediaminepropylesalicylaldimine Schiff base ligands, abbreviated as SBA/SA and SBA/EnSA respectively, were prepared and characterized by FT-IR, elemental analysis, TGA, XRD, TEM and SEM techniques. The potentials of these adsorbents were examined by using them in solid phase extraction of U(VI) ions from water samples. It is shown that 20 mg of SBA/SA or SBA/EnSA can remove rapidly (∼15 min) and quantitatively uranium(VI) ions from 10 to 200 mL of water solutions (pH 4) containing 0.2 mg of the ions, at 25 °C. The adsorbed ions were stripped by 1 mL of dilute nitric acid solution (0.1 mol L(-1)). It means that the studied adsorbents are able to be used for removal and concentration of uranyl ions. This allowed achieving to a concentration factor of 200 for uranyl ions. The variation in the ionic strength in the range 0-1 mol L(-1) did not affect the extraction efficiencies of the adsorbents. The adsorbents showed selective separation of uranyl ions from Cd(2+), Co(2+), Ni(2+), Mn(2+), Cr(3+), Ba(2+), Fe(3+) and Eu(3+) ions. Thermodynamic investigations revealed that the adsorption of uranyl ions by the adsorbents was spontaneous and endothermic. The Langmuir model described suitably the adsorption isotherms. This model determined the maximum adsorption capacity of the adsorbents SBA/SA and SBA/EnSA as 54 and 105.3 mg uranyl/g adsorbent, respectively. The kinetics of the processes was interpreted by using Pseudo-second-order model.

  16. High-energy heavy ion testing of VLSI devices for single event upsets and latch up

    Indian Academy of Sciences (India)

    S B Umesh; S R Kulkarni; R Sandhya; G R Joshi; R Damle; M Ravindra

    2005-08-01

    Several very large scale integrated (VLSI) devices which are not available in radiation hardened version are still required to be used in spacecraft systems. Thus these components need to be tested for highenergy heavy ion irradiation to find out their tolerance and suitability in specific space applications. This paper describes the high-energy heavy ion radiation testing of VLSI devices for single event upset (SEU) and single event latch up (SEL). The experimental set up employed to produce low flux of heavy ions viz. silicon (Si), and silver (Ag), for studying single event effects (SEE) is briefly described. The heavy ion testing of a few VLSI devices is performed in the general purpose scattering chamber of the Pelletron facility, available at Nuclear Science Centre, New Delhi. The test results with respect to SEU and SEL are discussed.

  17. 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.

  18. Bivalence Mn5O8 with hydroxylated interphase for high-voltage aqueous sodium-ion storage

    OpenAIRE

    Shan, Xiaoqiang; Charles, Daniel S.; Lei, Yinkai; Qiao, Ruimin; Wang, Guofeng; Yang, Wanli; Feygenson, Mikhail; Su, Dong; Teng, Xiaowei

    2016-01-01

    Aqueous electrochemical energy storage devices have attracted significant attention owing to their high safety, low cost and environmental friendliness. However, their applications have been limited by a narrow potential window (∼1.23 V), beyond which the hydrogen and oxygen evolution reactions occur. Here we report the formation of layered Mn5O8 pseudocapacitor electrode material with a well-ordered hydroxylated interphase. A symmetric full cell using such electrodes demonstrates a stable po...

  19. New 500-kV Ion Source Test Strand for HIF

    Energy Technology Data Exchange (ETDEWEB)

    Sangster, T.C.; Ahle, L.E.; Halaxa, E.F.; Karpenko, V.P.; Oldaker, M.E.; Mitchell, J.W.; Beck, D.N.; Bieniosek, F.M.; Henestroza, E.; Kwan, J.W.

    2000-03-09

    One of the most challenging aspects of ion beam driven inertial fusion energy is the reliable and efficient generation of low emittance, high current ion beams. The primary ion source requirements include a rise time of order 1-{micro}sec, a pulse width of at least 20-{micro}sec, a flattop ripple of less than 0.1% and a repetition rate of at least 5-HZ. Naturally, at such a repetition rate, the duty cycle of the source must be greater than 10{sup 8} pulses. Although these specifications do not appear to exceed the state-of-the-art for pulsed power, considerable effort remains to develop a suitable high current ion source. Therefore, we are constructing a 500-kV test stand specifically for studying various ion source concepts including surface, plasma and metal vapor arc. This paper will describe the test stand design specifications as well as the details of the various subsystems and components.

  20. Cytogenotoxicity of Cymbopogon citratus (DC Stapf (lemon grass aqueous extracts in vegetal test systems

    Directory of Open Access Journals (Sweden)

    Saulo M. Sousa

    2010-06-01

    Full Text Available The lemon grass, Cymbopogon citratus (DC Stapf, is an important species of Poaceae family commonly used in the folk medicine in many countries. The aim of this study was to investigate the cytotoxic and genotoxic effects of aqueous extracts from C. citratus leaves on Lactuca sativa (lettuce root tip meristem cells by cytogenetic studies that have never been done before for lemon grass extracts. For this, lettuce seeds were treated for 72h with different concentrations of lemon grass aqueous extracts (5; 10; 20 and 30 mg/mL. The percentage of germination, root development and cellular behavior were analyzed, and the results showed that the highest concentration of aqueous extracts reduced the mitotic index, the seed germination and the root development of lettuce. The extracts have also induced chromosome aberrations and cellular death in the roots cells of L. sativa.O capim-limão, Cymbopogon citratus (DC Stapf, é uma importante espécie da família Poaceae com uma comum utilização na medicina popular em vários países. O objetivo deste estudo foi investigar os efeitos citotóxicos e genotóxicos do extrato aquoso das folhas de C. citratus em células meristemáticas de Lactuca sativa (alface por meio de estudos citogenéticos, uma vez que estudos desta natureza não existem para extratos aquosos de capim-limão. Para isso, sementes de alface foram tratadas por 72h com diferentes concentrações de extratos aquosos feitos das folhas de capim-limão (5, 10, 20 e 30 mg/mL. O percentual de germinação, desenvolvimento radicular e o comportamento celular foram avaliados e os resultados mostraram que as concentrações mais elevadas dos extratos aquosos reduziram o índice mitótico, o percentual de germinação das sementes e desenvolvimento radicular da alface. Os extratos também induziram aberrações cromossômicas e morte celular nas células das raízes de L. sativa.

  1. Immobilization of 5-aminopyridine-2-tetrazole on cross-linked polystyrene for the preparation of a new adsorbent to remove heavy metal ions from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu; Chen, Youning; Wang, Chaozhan; Wei, Yinmao, E-mail: ymwei@nwu.edu.cn

    2014-07-15

    Highlights: • Novel chelating resin was prepared using pyridine-2-tetrazole as ligand. • The resin has quite high adsorption capacity for Cu(II), Pb(II) and Hg(II). • The resin shows the different selectivity from the common used IDA resin. • The preparation procedure is a two-step reaction and is easy to carry out. - Abstract: Novel 5-aminopyridine-2-tetrazole-functionalized polystyrene resin (APTZ-PS) was prepared by anchoring 5-aminopyridine-2-carbonitrile onto chloromethylated polystyrene beads (CMPS) and subsequently using the cyano-tetrazole conversion reaction. The APTZ-PS resin was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and specific surface area and pore size analyses. The adsorption experiments of the prepared resin for heavy metal ions were conducted by batch methods. The effects of the experimental conditions, such as pH, contact time and initial metal ion concentration on the adsorption properties of Cu(II), Pb(II) and Hg(II) were investigated. The results showed that the resin possessed perfect adsorption capacities for Cu(II), Pb(II) and Hg(II), and the selectivity was different from the commonly used iminodiacetic acid-chelating resin. The sorption kinetics of the three metal ions followed the pseudo-second-order equation. The adsorption isotherms for Cu(II) and Pb(II) could be better fitted by the Langmuir model than the Freundlich model, whereas the Freundlich model was the best for the Hg(II) ion. Even after five consecutive adsorption–desorption cycles, no obvious change in the adsorption capacity of the resin was found, which implied that the APTZ-PS resin was suitable for the efficient removal of heavy metal ions from aqueous solution.

  2. Removal of Ni{sup 2+} and Cu{sup 2+} ions from aqueous solution on to lignite-based carbons

    Energy Technology Data Exchange (ETDEWEB)

    Samra, S.E. [University of Mansoura, Mansoura (Egypt). Faculty of Science, Dept. of Chemistry

    2000-07-01

    Non-activated lignites were prepared by the carbonization of Egyptian lignite in a limited quantity of air at 500{degree}C, 700 {degree}C and 900 {degree}C, respectively. Zinc chloride-activated carbons were also prepared by the carbonization of lignite with 20 wt%, 40 wt% and 60 wt% zinc chloride in a limited quantity of air at 600 {degree}C. The surface areas of the resulting samples were determined from nitrogen adsorption studies at 77 K and from carbon dioxide adsorption studies at 298 K. The functional acidic groups on the surface were determined by neutralization with aqueous solutions of NaHCO{sub 3}, Na{sub 2}CO{sub 3} and NaOH, respectively. The sorption of Ni{sup 2+} and Cu{sup 2+} ions on the prepared carbons as well as on the as-received lignite were investigated. The influence of the time of contact, the initial ion concentration and the temperature was studied and the kinetics of the process were investigated. Equilibrium sorption isotherms were determined and the results interpreted by applying the Freundlich and Langmuir equations. The surface area was found to generally increase with increasing carbonization temperature. For activated carbons, the surface area increased with an increase in the amount of zinc chloride used in the activation process. The chemisorption of Ni{sup 2+} and Cu{sup 2+} ions on lignite-based carbon was found to be a pseudo-second order process. The acid sites on the surface provide active sites for the chemisorption of Ni{sup 2+} and Cu{sup 2+} ions and a qualitative relationship was found to exist between the maximum sorption capacity of these metal ions and the total surface acidity.

  3. Development and testing of the improved focusing quadrupole for heavy ion fusion accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Manahan, R R; Martovetsky, N N; Meinke, R B; Chiesa, L; Lietzke, A F; Sabbi, G L; Seidl, P A

    2003-10-23

    An improved version of the focusing magnet for a Heavy Ion Fusion (HIF) accelerator was designed, built and tested in 2002-2003. This quadrupole has higher focusing power and lower error field than the previous version of the focusing quadrupoles successfully built and tested in 2001. We discuss the features of the new design, selected fabrication issues and test results.

  4. Design and testing of the 2 MV heavy ion injector for the Fusion Energy Research Program

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, W.; Benjegerdes, R.; Reginato, L.; Stoker, J.; Hipple, R.; Peters, C.; Pruyn, J.; Vanecek, D.; Yu, S.

    1995-04-01

    The Fusion Energy Research Group at the Lawrence Berkeley Laboratory has constructed and tested a pulsed 2 MV injector that produces a driver size beam of potassium ions. This paper describes the engineering aspects of this development which were generated in a closely coupled effort with the physics staff. Details of the ion source and beam transport physics are covered in another paper at this conference. This paper discusses the design details of the pulse generator, the ion source, the extractor, the diode column, and the electrostatic quadrupole column. Included will be the test results and operating experience of the complete injector.

  5. Direct observation of the dynamics of single metal ions at the interface with solids in aqueous solutions

    Science.gov (United States)

    Ricci, Maria; Trewby, William; Cafolla, Clodomiro; Voïtchovsky, Kislon

    2017-02-01

    The dynamics of ions adsorbed at the surface of immersed charged solids plays a central role in countless natural and industrial processes such as crystal growth, heterogeneous catalysis, electrochemistry, or biological function. Electrokinetic measurements typically distinguish between a so-called Stern layer of ions and water molecules directly adsorbed on to the solid’s surface, and a diffuse layer of ions further away from the surface. Dynamics within the Stern layer remain poorly understood, largely owing to a lack of in-situ atomic-level insights. Here we follow the dynamics of single Rb+ and H3O+ ions at the surface of mica in water using high-resolution atomic force microscopy with 25 ms resolution. Our results suggest that single hydrated Rb+ions reside τ1 = 104 ± 5 ms at a given location, but this is dependent on the hydration state of the surface which evolves on a slower timescale of τ2 = 610 ± 30 ms depending on H3O+ adsorption. Increasing the liquid’s temperature from 5 °C to 65 °C predictably decreases the apparent glassiness of the interfacial water, but no clear effect on the ions’ dynamics was observed, indicating a diffusion-dominated process. These timescales are remarkably slow for individual monovalent ions and could have important implications for interfacial processes in electrolytes.

  6. Phosphorescent Chemosensor Based on Iridium(III) Complex for the Selective Detection of Cu(II) Ion in Aqueous Acetonitrile

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyebin; Li, Yinan; Hyun, Myungho [Pusan National Univ., Busan (Korea, Republic of)

    2013-02-15

    Iridium(III) complex 1 containing two cyclo-metalating 2-phenylpyridine (ppy) ligands and one 2,2'-bipyridine ligand tethered with two DPA moieties by a methylene linker was prepared. Iridium(III) complex 1 was found to form 1:2 complex selectively with Cu(II) ion with the Stern-Volmer constant of 5.8 Χ 10{sup 4} M{sup -1}. Cu(II) ion has two sides. In one side, Cu(II) ion is an important cofactor in nearly 20 metalloenzymes and an essential micronutrient for all living systems. But, in other side, Cu(II) ion is one of significant metal pollutants and toxic to living cells if present in slightly high concentrations, causing neurodegenerative diseases such as Menkes and Wilson's disease. In this instance, the selective detection of Cu(II) ion in environment and in living systems is very important. Consequently, various fluorescent chemosensors for the highly sensitive and selective detection of Cu (II) ion have been developed.

  7. Enhanced selective removal of Cu(II) from aqueous solution by novel polyethylenimine-functionalized ion imprinted hydrogel: Behaviors and mechanisms.

    Science.gov (United States)

    Wang, Jingjing; Li, Zhengkui

    2015-12-30

    A novel polyethylenimine-functionalized ion-imprinted hydrogel (Cu(II)-p(PEI/HEA)) was newly synthesized by (60)Co-γ-induced polymerization for the selective removal of Cu(II) from aqueous solution. The adsorption performances including the adsorption capacity and selectivity of the novel hydrogel were much better than those of similar adsorbents reported. The hydrogel was characterized via scanning electron microscope, transmission electron microscopy, Fourier transform infrared spectra, thermal gravimetric analysis and X-ray photoelectron spectroscopy to determine the structure and mechanisms. The adsorption process was pH and temperature sensitive, better fitted to pseudo-second-order equation, and was Langmuir monolayer adsorption. The maximum adsorption capacity for Cu(II) was 40.00 mg/g. The selectivity coefficients of ion-imprinted hydrogel for Cu(II)/Pb(II), Cu(II)/Cd(II) and Cu(II)/Ni(II) were 55.09, 107.47 and 63.12, respectively, which were 3.93, 4.25 and 3.53 times greater than those of non-imprinted hydrogel, respectively. Moreover, the adsorption capacity of Cu(II)-p(PEI/HEA) could still keep more than 85% after four adsorption-desorption cycles. Because of such enhanced selective removal performance and excellent regeneration property, Cu(II)-p(PEI/HEA) is a promising adsorbent for the selective removal of copper ions from wastewater.

  8. Removal of Pb(II) ions from aqueous solution by a waste mud from copper mine industry: equilibrium, kinetic and thermodynamic study.

    Science.gov (United States)

    Ozdes, Duygu; Gundogdu, Ali; Kemer, Baris; Duran, Celal; Senturk, Hasan Basri; Soylak, Mustafa

    2009-07-30

    The objective of this study was to assess the adsorption potential of a waste mud (WM) for the removal of lead (Pb(II)) ions from aqueous solutions. The WM was activated with NaOH in order to increase its adsorption capacity. Adsorption studies were conducted in a batch system as a function of solution pH, contact time, initial Pb(II) concentration, activated-waste mud (a-WM) concentration, temperature, etc. Optimum pH was specified as 4.0. The adsorption kinetic studies indicated that the overall adsorption process was best described by pseudo-second-order kinetics. The equilibrium adsorption capacity of a-WM was obtained by using Langmuir and Freundlich isotherm models and both models fitted well. Adsorption capacity for Pb(II) was found to be 24.4 mg g(-1) for 10 g L(-1) of a-WM concentration. Thermodynamic parameters including the Gibbs free energy (Delta G degrees), enthalpy (Delta H degrees), and entropy (DeltaS degrees) indicated that the adsorption of Pb(II) ions on the a-WM was feasible, spontaneous and endothermic, at temperature range of 0-40 degrees C. Desorption studies were carried out successfully with diluted HCl solutions. The results indicate that a-WM can be used as an effective and no-cost adsorbent for the treatment of industrial wastewaters contaminated with Pb(II) ions.

  9. Biosorption characteristics of Aspergillus flavus biomass for removal of Pb(II) and Cu(II) ions from an aqueous solution.

    Science.gov (United States)

    Akar, Tamer; Tunali, Sibel

    2006-10-01

    The Pb(II) and Cu(II) biosorption characteristics of Aspergillus flavus fungal biomass were examined as a function of initial pH, contact time and initial metal ion concentration. Heat inactivated (killed) biomass was used in the determination of optimum conditions before investigating the performance of pretreated biosorbent. The maximum biosorption values were found to be 13.46 +/- 0.99 mg/g for Pb(II) and 10.82 +/- 1.46 mg/g for Cu(II) at pH 5.0 +/- 0.1 with an equilibrium time of 2 h. Detergent, sodium hydroxide and dimethyl sulfoxide pretreatments enhanced the biosorption capacity of biomass in comparison with the heat inactivated biomass. The biosorption data obtained under the optimum conditions were well described by the Freundlich isotherm model. Competitive biosorption of Pb(II) and Cu(II) ions was also investigated to determine the selectivity of the biomass. The results indicated that A. flavus is a suitable biosorbent for the removal of Pb(II) and Cu(II) ions from aqueous solution.

  10. Adsorption of Hg2+, Cu2+ and Zn2+ ions from aqueous solution using formaldehyde cross-linked modified chitosan-thioglyceraldehyde Schiff's base.

    Science.gov (United States)

    Monier, M

    2012-04-01

    A chitosan-thioglyceraldehyde Schiff's base cross-linked magnetic resin (CSTG) was prepared and characterized using various instrumental methods. Then, the prepared resin was used for comparative studies on the removal of toxic metal ions like: Hg(2+), Cu(2+) and Zn(2+) from aqueous solutions. The effects of the initial pH value of the solution, contact time, the initial metal ion concentration and temperature on the adsorption capacity of the composite were investigated. The kinetics data were analyzed by pseudo-first order and pseudo-second order equations. The adsorption kinetics was well described by the pseudo-second order equation, and the adsorption isotherms were better fitted by the Langmuir equation. The maximum theoretical adsorption capacities of the CSTG resin for Hg(2+), Cu(2+) and Zn(2+) were found to be 98±2, 76±1 and 52±1 mg g(-1), respectively. The negative values of Gibbs free energy of adsorption (ΔG(ads°) indicated the spontaneity of the adsorption of all metal ions on the novel resin.

  11. 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.

  12. Removal of nickel(II) ions from aqueous solutions using the natural clinoptilolite and preparation of nano-NiO on the exhausted clinoptilolite

    Science.gov (United States)

    Rajic, Nevenka; Stojakovic, Djordje; Jovanovic, Mina; Logar, Natasa Zabukovec; Mazaj, Matjaz; Kaucic, Venceslav

    2010-12-01

    The natural zeolite tuff (clinoptilolite) from a Serbian deposit has been studied as adsorbent for Ni(II) ions from aqueous solutions. Its sorption capacity at 298 K varies from 1.9 mg Ni g -1 (for the initial solution concentration of 100 mg Ni dm -3) to 3.8 mg Ni g -1 (for C0 = 600 mg Ni dm -3) and it increases 3 times at 338 K. The sorption is best described by the Sips isotherm model. The sorption kinetics follows the pseudo-second-order model, the activation energies being 7.44, 5.86, 6.62 and 6.63 kJ mol -1 for C0 = 100, 200, 300 and 400 mg Ni dm -3, respectively. The sorption involves a film diffusion, an intra-particle diffusion, and a chemical cation-exchange between the Na + ions of clinoptilolite and the Ni 2+ ions. The sorption is endothermic (Δ H° being 37.9, 33.4, 30.0, 27.7 and 24.3 kJ mol -1 for C0 = 100, 200, 300, 400 and 600 mg Ni dm -3, respectively) and spontaneous in the 298-338 K temperature range. Thermal treatment of the Ni(II)-loaded clinoptilolite results in the formation of spherical nano-NiO particles of approx. 5 nm in diameter which are randomly dispersed in the clinoptilolite lattice.

  13. Preconcentration and determination of trace metal ions from aqueous samples by newly developed gallic acid modified Amberlite XAD-16 chelating resin.

    Science.gov (United States)

    Sharma, R K; Pant, Parul

    2009-04-15

    Gallic acid was immobilized on Amberlite XAD-16 by coupling it through -N=N group. The resulting chelating resin Amberlite XAD-16 gallic acid, characterized by thermogravimetric analysis (TGA), infrared (IR) spectra and BET analysis, was used to preconcentrate Cr(III), Mn(II),Fe(III),Co(II), Ni(II) and Cu(II)ions. The resin was employed for the preconcentration of the metal ions present in river water and industrial area aqueous samples. Several parameters like effect of pH, effect of time, effect of sample volume and flow rate of sample were investigated. The sorption capacities for the resin were 216 micromol g(-1), 180 micromol g(-1), 403 micromol g(-1), 281 micromol g(-1), 250 micromol g(-1) and 344 micromol g(-1) for Cr(III), Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) respectively. The preconcentration factors for Cr(III), Mn(II), Fe(III), Ni(II), Co(II) and Cu(II) were found out to be 300, 200, 400, 285.7, 300 and 400 respectively. The effect of various interfering ions was also studied. Results were validated by using standard addition method for river water sample.

  14. Review of progresses on clinical applications of ion selective electrodes for electrolytic ion tests: from conventional ISEs to graphene-based ISEs

    Directory of Open Access Journals (Sweden)

    Rongguo Yan

    2016-10-01

    Full Text Available There exist several positively and negatively charged electrolytes or ions in human blood, urine, and other body fluids. Tests that measure the concentration of these ions in clinics are performed using a more affordable, portable, and disposable potentiometric sensing method with few sample volumes, which requires the use of ion-selective electrodes (ISEs and reference electrodes. This review summarily descriptively presents progressive developments and applications of ion selective electrodes in medical laboratory electrolytic ion tests, from conventional ISEs, solid-contact ISEs, carbon nanotube based ISEs, to graphene-based ISEs.

  15. Heavy ion beams from an Alphatross source for use in calibration and testing of diagnostics

    Science.gov (United States)

    Ward, R. J.; Brown, G. M.; Ho, D.; Stockler, B. F. O. F.; Freeman, C. G.; Padalino, S. J.; Regan, S. P.

    2016-10-01

    Ion beams from the 1.7 MV Pelletron Accelerator at SUNY Geneseo have been used to test and calibrate many inertial confinement fusion (ICF) diagnostics and high energy density physics (HEDP) diagnostics used at the Laboratory for Laser Energetics (LLE). The ion source on this accelerator, a radio-frequency (RF) alkali-metal charge exchange source called an Alphatross, is designed to produce beams of hydrogen and helium isotopes. There is interest in accelerating beams of carbon, oxygen, argon, and other heavy ions for use in testing several diagnostics, including the Time Resolved Tandem Faraday Cup (TRTF). The feasibility of generating these heavy ion beams using the Alphatross source will be reported. Small amounts of various gases are mixed into the helium plasma in the ion source bottle. A velocity selector is used to allow the desired ions to pass into the accelerator. As the heavy ions pass through the stripper canal of the accelerator, they emerge in a variety of charge states. The energy of the ion beam at the high-energy end of the accelerator will vary as a function of the charge state, however the maximum energy deliverable to target is limited by the maximum achievable magnetic field produced by the accelerator's steering magnet. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  16. Review of progresses on clinical applications of ion selective electrodes for electrolytic ion tests: from conventional ISEs to graphene-based ISEs

    OpenAIRE

    Rongguo Yan; Shuai Qiu; Lei Tong; Yin Qian

    2016-01-01

    There exist several positively and negatively charged electrolytes or ions in human blood, urine, and other body fluids. Tests that measure the concentration of these ions in clinics are performed using a more affordable, portable, and disposable potentiometric sensing method with few sample volumes, which requires the use of ion-selective electrodes (ISEs) and reference electrodes. This review summarily descriptively presents progressive developments and applications of ion selective electro...

  17. A G-pentaplex-based assay for Cs(+) ions in aqueous solution using a luminescent Ir(III) complex.

    Science.gov (United States)

    Lin, Sheng; Yang, Chao; Mao, Zhifeng; He, Bingyong; Wang, Yi-Tao; Leung, Chung-Hang; Ma, Dik-Lung

    2016-03-15

    A series of 5 randomly designed in-house cyclometalated Ir(III) complexes were examined for their application in G-pentaplex probes and the "proof-of-principle" concept in G-pentaplex-based Cs(+) ions detection. The G-pentaplex-forming sequence (DNA1, 5'-T(iG)4T-3', where iG=isoguanine) is present in single strand DNA form ab initio, however, the addition of Cs(+) ions lead to formation of the intermolecular G-pentaplex structure which is identified by the novel Ir(III) complex 1 afterward and produce an enhanced luminescence signal for Cs(+) ions monitoring. To the best of our knowledge, this is the first G-pentaplex probe and also the first G-pentaplex-based label-free detection platform for Cs(+) ions reported in the literature. The monitoring of spiked Cs(+) ions in natural water samples demonstrates the potential application and technical sound of this "proof-of-principle" concept sensing platform.

  18. Surface adsorption and self-assembly of Cu(II) ions on TEMPO-oxidized cellulose nanofibers in aqueous media.

    Science.gov (United States)

    Liu, Peng; Oksman, Kristiina; Mathew, Aji P

    2016-02-15

    TEMPO-mediated oxidized cellulose nanofibers (TOCNFs) have shown potential in the bioremediation of metal ions from contaminated water due to their interaction with positively charged metal ions via electrostatic interactions involving surface carboxyl groups. Copper is one of the most common pollutants in industrial effluents and is thus the target metal in the current study. The specific surface adsorption of Cu(II) was similar for TOCNFs with different degrees of functionalization and directly impacted the zeta potential. SEM imaging of the TOCNF after Cu(II) adsorption revealed interesting nanostructured clusters that were attributable to Cu(II) ions first being adsorbed by carboxylate groups on the TOCNF and subsequently being reduced and self-assembled to Cu(0) nanoparticles (NPs) or copper oxide NPs by microprecipitation. TOCNF turned superhydrophilic and resulted in faster water filtration after copper adsorption due to the stronger polarity of the copper ions or the self-assembled Cu(0) NPs creating voids or highly water-permeable channels at the interface between the interconnected TEMPO-oxidized nanofibers. Thus, the adsorption of Cu(II) ions and self-assembly into the Cu NPs on TOCNF favors a faster water purification process and provides a viable route to reuse/recycle TOCNFs studded with Cu nanoparticles as biocidal materials.

  19. Aqueous sulfuric acid as the mobile phase in cation ion chromatography for determination of histamine, putrescine, and cadaverine in fish samples.

    Science.gov (United States)

    Liao, Benjamin S; Sram, Jackie; Cain, Teresa T; Halcrow, Kenneth R

    2011-01-01

    Aqueous sulfuric acid can be used as the mobile phase in cation ion chromatography to separate the three biogenic amines, putrescine, cadaverine, and histamine, from fish. Various concentrations of aqueous sulfuric acid were investigated to optimize the separation of these three biogenic amines. Aqueous sulfuric acid (5.0 mM) was found to be optimum for the separation and was used to determine the three biogenic amines in fish. The LOQ, defined as the lowest level of the standard calibration curve, was 0.055 ppm (equivalent to 0.55 microg/g sample) for putrescine, 0.05 ppm (equivalent to 0.5 microg/g sample) for cadaverine, and 1.0 ppm (equivalent to 10 microg/g sample) for histamine. From statistical analysis of the LOQ, the method detection limit was 0.003 ppm for putrescine, 0.009 ppm for cadaverine, and 0.16 ppm for histamine. For sample preparation, the fish was composited, homogenized in methanol-water (75 + 25, v/v), incubated for 15 min at 60 degrees C, and centrifuged. The sample solution was micron-filtered before injection. The mobile phase flow rate was 0.8 mL/min under isocratic conditions at room temperature (15-25 degrees C). The three biogenic amines were separated in the order of increasing retention time, i.e., putrescine, cadaverine, and histamine, within 30 min. The chromatograms showed complete peak separation of the three amines regardless of the difference in fish matrixes.

  20. The synthesis of (N 2O 2S 2)-Schiff base ligands and investigation of their ion extraction capability from aqueous media

    Science.gov (United States)

    Zoubi, Wail A. L.; Kandil, Farouk; Chebani, Mohamad Khaled

    2011-09-01

    Two new Schiff bases (I) and (II) containing nitrogen-sulfur-oxygen donor atoms were designed and synthesized in a multi-step reaction sequence. The Schiff base (I) was used in solvent extraction of metal chlorides such as Cu 2+ and Cr 3+ as well as metal picrates such as Hg 2+ and UO 22+ from aqueous phase to the organic phase. The influences of the parameter functions, such as pH, solvent, ionic strength of aqueous phase, aqueous to organic phase and concentration of the extractant were investigated to shed light on their chemical extracting properties upon the extractability of metal ions. The effect of chloroform, dichloromethane and nitrobenzene as organic solvents over the metal chlorides extraction was investigated at 25 ± 0.1 °C by using flame atomic absorption and the result is that the ability of extraction in solvents as follows: C 6H 5NO 2 > CHCl 3 > CH 2Cl 2 and the compositions of the extracted species have been determined. The metal picrate extraction was investigated at 25 ± 0.1 °C by using UV-visible spectrometry. As well that the extraction of picrates metal such as UO 22+ and Hg 2+ with Schiff base(I) in absence and presence of 2-(2-aminoethyl) pyridine was investigated in chloroform. The extraction results revealed the presence of neutral donors 2-(2-aminoethyl) pyridine shifts the extraction percentage curves towards higher pH region, indicating a synergistic effect of this donors on extraction of UO 22+ and Hg 2+ by the studied Schiff base (I).

  1. Magnetic beads-based DNAzyme recognition and AuNPs-based enzymatic catalysis amplification for visual detection of trace uranyl ion in aqueous environment.

    Science.gov (United States)

    Zhang, Hongyan; Lin, Ling; Zeng, Xiaoxue; Ruan, Yajuan; Wu, Yongning; Lin, Minggui; He, Ye; Fu, FengFu

    2016-04-15

    We herein developed a novel biosensor for the visual detection of trace uranyl ion (UO2(2+)) in aqueous environment with high sensitivity and specificity by using DNAzyme-functionalized magnetic beads (MBs) for UO2(2+) recognition and gold nano-particles (AuNPs)-based enzymatic catalysis oxidation of TMB (3,3',5,5'-tetramethylbenzidine sulfate) for signal generation. The utilization of MBs facilitates the magnetic separation and collection of sensing system from complex sample solution, which leads to more convenient experimental operation and more strong resistibility of the biosensor to the matrix of sample, and the utilization of AuNPs-based enzymatic catalysis amplification greatly improved the sensitivity of the biosensor. Compared with the previous DNAzyme-based UO2(2+) sensors, the proposed biosensor has outstanding advantages such as relative high sensitivity and specificity, operation convenience, low cost and more strong resistibility to the matrix of sample. It can be used to detect as low as 0.02 ppb (74 pM) of UO2(2+) in aqueous environment by only naked-eye observation and 1.89 ppt (7.0 pM) of UO2(2+) by UV-visible spectrophotometer with a recovery of 93-99% and a RSD ≤ 5.0% (n=6) within 3h. Especially, the visual detection limit of 0.02 ppb (74 pM) is much lower than the maximum allowable level of UO2(2+) (130 nM) in the drinking water defined by the U.S. Environmental Protection Agency (EPA), indicating that our method meets the requirement of rapid and on-site detection of UO2(2+) in the aqueous environment by only naked-eye observation.

  2. Anion-intercalated layered double hydroxides modified test strips for detection of heavy metal ions.

    Science.gov (United States)

    Wang, Nan; Sun, Jianchao; Fan, Hai; Ai, Shiyun

    2016-01-01

    In this work, a novel approach for facile and rapid detection of heavy metal ions using anion-intercalated layered double hydroxides (LDHs) modified test strips is demonstrated. By intercalating Fe(CN)6(4-) or S(2-) anions into the interlayers of LDHs on the filter paper, various heavy metal ions can be easily detected based on the color change before and after reaction between the anions and the heavy metal ions. Upon the dropping of heavy metal ions solutions to the test strips, the colors of the test strips changed instantly, which can be easily observed by naked eyes. With the decrease of the concentration, the color depth changed obviously. The lowest detection concentration can be up to 1×10(-6) mol L(-1). Due to the easily intercalation of anions into the interlayer of the LDHs on test trips, this procedure provides a general method for the construction of LDHs modified test strips for detection of heavy metal ions. The stability of the prepared test strips is investigated. Furthermore, all the results were highly reproducible. The test strips may have potential applications in environmental monitoring fields.

  3. Thermodynamic modeling of naringenin protonation equilibria in NaClO4 aqueous solutions by specific ion interaction theory and Pitzer equations

    Indian Academy of Sciences (India)

    Morteza Jabbari; Rahele Zhiani; Ali Farajtabar

    2015-06-01

    The protonation equilibria for the flavonoid naringenin were studied at 25°C using combined multiwavelength spectroscopic and pH-potentiometric methods as a function of the ionic strength. Over a wide range of ionic strengths, 0.10–3.00 mol dm−3, the investigation was performed in different aqueous solutions of NaClO4 as the background electrolyte. The dependence on ionic strength of protonation constants was modeled by the Brönsted–Guggenheim–Scatchard Specific Ion Interaction Theory (SIT) and Pitzer approaches. Apart from the values of SIT interaction coefficients and Pitzer parameters, the protonation constants at infinite dilution (zero ionic strength) were obtained. On the basis of these results, it was found that Pitzer mode l gives more satisfactory results rather than the SIT method.

  4. Separation of clavulanic acid from fermented broth of amino acids by an aqueous two-phase system and ion-exchange adsorption.

    Science.gov (United States)

    da Silva, Clovis Sacardo; Cuel, Maressa Fabiano; Barreto, Verônica Orlandin; Kwong, Wu Hong; Hokka, Carlos O; Barboza, M

    2012-02-15

    The clavulanic acid is a substance which inhibits the β-lactamases used with penicillins for therapeutic treatment. After the fermentation, by-products of low molecular weight such as amino acids lysine, histidine, proline and tyrosine are present in the fermented broth. To remove these impurities the techniques of extraction by an aqueous two-phase system of 17% polyethylene glycol molecular weight 600 and 15% potassium phosphate were used for a partial purification. A subsequent ion-exchange adsorption was used for the recuperation of the clavulanic acid of the top phase and purification getting a concentration factor of 2 and purification of 100% in relation to the amino acids lysine, histidine, proline and tyrosine.

  5. Preparation and characterization of chelating fibers based on natural wool for removal of Hg(II), Cu(II) and Co(II) metal ions from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Monier, M., E-mail: monierchem@yahoo.com [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt); Nawar, N., E-mail: nnawar@mans.edu.eg [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt); Abdel-Latif, D.A. [Chemistry Department, Faculty of Science, Mansoura University, 35516 (Egypt)

    2010-12-15

    The graft copolymerization of acrylonitrile (AN) onto natural wool fibers initiated by KMnO{sub 4} and oxalic acid combined redox initiator system in limited aqueous medium was carried out in heterogeneous media. Moreover, modification of the grafted wool fibers was done by changing the nitrile group (-CN) into cyano-acetic acid {alpha}-amino-acrylic-hydrazide through the reaction with hydrazine hydrate followed by ethylcyanoacetate which eventually produce wool-grafted-poly(cyano-acetic acid {alpha}-amino-acrylic-hydrazide) (wool-g-PCAH) chelating fibers. The application of the modified fibers for metal ion uptake was studied using Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+}. The modified chelating fibers were characterized using FTIR spectroscopy, SEM and X-ray diffraction.

  6. A plant wide aqueous phase chemistry model describing pH variations and ion speciation/pairing in wastewater treatment process models

    DEFF Research Database (Denmark)

    Flores-Alsina, X.; Mbamba, C. Kazadi; Solon, K.;

    There is a growing interest within the Wastewater Treatment Plant (WWTP) modelling community to correctly describe physico-chemical processes after many years of mainly focusing on biokinetics (Batstone et al., 2012). Indeed, future modelling needs, such as a plant-wide phosphorus (P) description......, require a major, but unavoidable, additional degree of complexity when representing cationic/anionic behaviour in Activated Sludge (AS)/Anaerobic Digestion (AD) systems (Ikumi et al., 2014). In this paper, a plant-wide aqueous phase chemistry module describing pH variations plus ion speciation......). Simulation results show pH predictions when describing Biological Nutrient Removal (BNR) by the activated sludge models (ASM) 1, 2d and 3 (Henze et al., 2000) comparing the performance of a nitrogen removal (WWTP1) and a combined nitrogen and phosphorus removal (WWTP2) treatment plant configuration under...

  7. Modification of a montmorillonite-illite clay using alkaline hydrothermal treatment and its application for the removal of aqueous Cs+ ions.

    Science.gov (United States)

    Oztop, B; Shahwan, T

    2006-03-15

    A montmorillonite-illite clay was modified using alkaline hydrothermal treatment (reflux method) and applied to the removal of aqueous Cs+ ions. The alkaline solutions were prepared by dissolving NaOH in seawater and in distilled water, and the effect of the two alkaline media on the sorption capacities of the modified clay was discussed. The modified materials were characterized using XRD, SEM/EDS, and FTIR. As a result of the modification, the original mineral was partially transformed into a zeolitic material with spherical morphology. The results showed that the modification improved the Cs+ uptake capacity of the starting clay, with the clay modified in distilled water medium demonstrating higher sorption capacity. The sorption data were adequately described using the Freundlich and Dubinin-Radushkevich isotherm models.

  8. Preparation and Characterization of Poly(ethyl hydrazide Grafted Oil Palm Empty Fruit Bunch for Removal of Ni(II Ion in Aqueous Environment

    Directory of Open Access Journals (Sweden)

    Siti Mariam Mohd Nor

    2013-07-01

    Full Text Available Poly(ethyl hydrazide grafted oil palm empty fruit bunch (peh-g-opefb fiber has been successfully prepared by heating poly(methylacrylate-g-opefb at 60 °C for 4 h in a solution of hydrazine hydrate in ethanol. The chelating ability of peh-g-opefb was evaluated based on removal of Ni(II ions in aqueous solution. Adsorption of Ni(II by peh-g-opefb was characterized based on effect of pH, isotherm, kinetic and thermodynamic study. This cheap sorbent based on oil palm empty fruit bunch fiber has a great future potential in water treatment industries based on high adsorption capacity, biodegradability and renewability.

  9. ADSORPTION OF CHROMIUM (VI FROM AQUEOUS SOLUTIONS BY DIFFERENT ADMIXTURES – A BATCH EQUILIBRIUM TEST STUDY

    Directory of Open Access Journals (Sweden)

    K. SHIVA PRASHANTH KUMAR

    2014-08-01

    Full Text Available Wide variety of inorganic compounds such as nutrients and trace metals, organic chemicals, radioactive contaminants and pathogens are commonly present as contaminants in the groundwater. Migration of contaminants in soil involves important mechanisms such as molecular diffusion, dispersion under physical processes, adsorption, precipitation and oxidation - reduction under chemical processes and biodegradation under biological process. Cr (VI is a major and dangerous contaminant as per the ground water is concerned. There are numerous research work carried out with concentrated efforts by the researchers towards removal of Cr (VI contaminant from aqueous solutions. There are few studies relevant to Cr (VI removal with respect to utilization of low cost admixtures and also soil type. In the present study, different low cost admixtures like rice husk (RH, shredded tyre (ST and fly ash (FA are used to understand the performance in removal of Cr (VI from aqueous solution and also two different soil types are used along with the admixture. The results are discussed in terms of sorption capacity and performance of individual admixture and combination of admixture with soil in removal of contaminant. The fly ash, rice husk and shredded tyre admixtures are used and the results revealed that the shredded tyre showed higher performance in removal of contaminant concentration. Also, the soil which has more fine particle content (size<0.075 mm IS sieve showed reasonable reduction in concentration of contaminant at the lower levels of contaminant initial concentration. The sorption capacity results of Cr (VI contaminant, treated with various admixtures are further validated with the published work of other investigators. The shredded tyre (ST showed more adsorption capacity, i.e., 3.283 mg/g at pH of 4.8. For other admixtures, adsorption capacity value is varying in the range of 0.07 mg/g to 1.7 mg/g. Only in case of activated alumina and modified saw dust

  10. [Technical support in the testing of microoganisms for their ability to accumulate strontium and cesium from aqueous solutions]. Final reports, Task order No. 2

    Energy Technology Data Exchange (ETDEWEB)

    1987-06-15

    This report describes the binding of cesium and strontium ions from aqueous solution in a variety of microorganisms. Data is provided on the absorption by Ashbya gossyppi, Chlorella pyrenoidosa, Candida sp. Ml13, Saccharomyces cerevisiae, Scenedesmus obliqus, Streptococcus mutans, Anabaena flosaquae, Escherichia coli, Streptomyces viridochromogenes, Chlamydomonas reinhardtii, Rhizopus oryzae, Bacillus megaterium, Micrococcus luteus, Zoogloea ramigera, Coelastrum proboscideum, Pseudomonas aeruginosa, Citrobacter freundii, Paecilomyces marquandi, and Caulobacter fusiformis.

  11. Speciation study on the interaction of some divalent transition metal ions with succinic acid dihydrazide in aqueous medium.

    Science.gov (United States)

    Satyanarayana, Atreyapurapu; Kenie, Dunkana Negussa; Shyamala, Pulipaka

    2013-01-01

    The interaction of succinic acid dihydrazide with Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) was investigated in aqueous medium at 303K and ionic strength of 0.1 mol dm-3. The speciation and stability constants of the metal complexes formed were determined by pH-metric method. Mononuclear and homo binuclear species in different protonation and deprotonation states were identified, the corresponding formation constants calculated using MINIQUAD-75 computer program, and species distribution diagrams produced using the HYSS computer program. Selection of the best-fit chemical models was based on statistical parameters.

  12. High-Performance Olivine NaFePO4 Microsphere Cathode Synthesized by Aqueous Electrochemical Displacement Method for Sodium Ion Batteries.

    Science.gov (United States)

    Fang, Yongjin; Liu, Qi; Xiao, Lifen; Ai, Xinping; Yang, Hanxi; Cao, Yuliang

    2015-08-19

    Olivine NaFePO4/C microsphere cathode is prepared by a facile aqueous electrochemical displacement method from LiFePO4/C precursor. The NaFePO4/C cathode shows a high discharge capacity of 111 mAh g(-1), excellent cycling stability with 90% capacity retention over 240 cycles at 0.1 C, and high rate capacity (46 mAh g(-1) at 2 C). The excellent electrochemical performance demonstrates that the aqueous electrochemical displacement method is an effective and promising way to prepare NaFePO4/C material for Na-based energy storage applications. Moreover, the Na2/3FePO4 intermediate is observed for the first time during the Na intercalation process through conventional electrochemical techniques, corroborating an identical two-step phase transition reaction both upon Na intercalation and deintercalation processes. The clarification of the electrochemical reaction mechanism of olivine NaFePO4 could inspire more attention on the investigation of this material for Na ion batteries.

  13. Optimization of multicomponent aqueous suspensions of lithium iron phosphate (LiFePO4) nanoparticles and carbon black for lithium-ion battery cathodes.

    Science.gov (United States)

    Li, Jianlin; Armstrong, Beth L; Daniel, Claus; Kiggans, Jim; Wood, David L

    2013-09-01

    Addition of polyethyleneimine (PEI) to aqueous LiFePO4 nanoparticle suspensions improves stability and reduces agglomerate size, which is beneficial to lithium-ion battery cathode manufacturing. This research examines the effect of both PEI concentration and molecular weight (MW) on dispersing LiFePO4 and Super P C45 in multicomponent aqueous suspensions. It is demonstrated that the optimal conditions for obtaining stable suspensions with minimal agglomerate size are 1.5 wt% PEI with MW=2000 g mol(-1) and 5.0 wt% PEI with MW=10,000 g mol(-1) for LiFePO4 and Super P C45, respectively. The mixing sequence also affects rheological properties of these suspensions. It is found that dispersing the LiFePO4 and Super P C45 separately yielded suspensions with superior properties (Newtonian rheological behavior, smaller agglomerate size, improved settling, etc.). In particular, dispersing the LiFePO4 prior to the Super P C45 when making the final multicomponent suspension is found to be beneficial, which was evidenced by higher half-cell discharge capacity.

  14. Adsorption of lead and copper ions from aqueous effluents on rice husk ash in a dynamic system

    Directory of Open Access Journals (Sweden)

    M. G. A. Vieira

    2014-06-01

    Full Text Available This study evaluated the kinetic adsorption of Pb and Cu ions using rice husk ash as adsorbent in a fixed bed. The maximum adsorption capacities obtained for lead and copper ions in the fixed bed were 0.0561 and 0.0682 mmol/g (at 20 ºC, respectively. The thermodynamic studies indicated that the lead adsorption process was exothermic and spontaneous, while the copper adsorption process was endothermic and spontaneous. Characterization results indicated the presence of several functional groups, amorphous silica and a fibrous and longitudinal structure of rice husks. Rice husk ash (RHA from northern Brazil can be used as a bioadsorbent for the individual removal of Pb(II and Cu(II ions from metal-containing effluents.

  15. Uranium Adsorption on Ion-Exchange Resins - Batch Testing

    Energy Technology Data Exchange (ETDEWEB)

    Mattigod, Shas V.; Golovich, Elizabeth C.; Wellman, Dawn M.; Cordova, Elsa A.; Smith, Ronald M.

    2010-12-01

    The uranium adsorption performance of five resins (Dowex 1, Dowex 21K 16-30 [fresh], Dowex 21K 16-30 [regenerated], Purofine PFA600/4740, and ResinTech SIR-1200) were tested using unspiked, nitrate-spiked, and nitrate-spiked/pH adjusted source water from well 299-W19-36. These batch tests were conducted in support of a resin selection process in which the best resin to use for uranium treatment in the 200-West Area groundwater pump-and-treat system will be identified. The results from these tests are as follows: • The data from the high-nitrate (1331 mg/L) tests indicated that Dowex 1, Dowex 21K 16-30 (fresh), Purofine PFA600/4740, and ResinTech SIR-1200 all adsorbed uranium similarly well with Kd values ranging from ~15,000 to 95,000 ml/g. All four resins would be considered suitable for use in the treatment system based on uranium adsorption characteristics. • Lowering the pH of the high nitrate test conditions from 8.2 to 7.5 did not significantly change the uranium adsorption isotherms for the four tested resins. The Kd values for these four resins under high nitrate (1338 mg/L), lower pH (7.5) ranged from ~15,000 to 80,000 ml/g. • Higher nitrate concentrations greatly reduced the uranium adsorption on all four resins. Tests conducted with unspiked (no amendments; nitrate at 337 mg/L and pH at 8.2) source water yielded Kd values for Dowex 1, Dowex 21K 16-30 (fresh), Purofine PFA600/4740, and ResinTech SIR-1200 resins ranging from ~800,000 to >3,000,000 ml/g. These values are about two orders of magnitude higher than the Kd values noted from tests conducted using amended source water. • Compared to the fresh resin, the regenerated Dowex 21K 16-30 resin exhibited significantly lower uranium-adsorption performance under all test conditions. The calculated Kd values for the regenerated resin were typically an order of magnitude lower than the values calculated for the fresh resin. • Additional testing using laboratory columns is recommended to better

  16. Effects of dissolved Ca2+, Mg2+, and Na+ ions on the supramolecular aggregation of natural organic matter in aqueous solutions

    Science.gov (United States)

    Ahn, W.; Kalinichev, A. G.; Clark, M. M.

    2008-12-01

    The complexation of natural organic matter (NOM) with metal ions, minerals and organic species in soil and water allows NOM to form water-soluble and water-insoluble aggregates of widely differing chemical and biological stabilities. Metal-NOM interaction induces strong correlations between the concentration of natural organic matter and the speciation, solubility and toxicity of many metals in the environment. In water purification and desalination, NOM is also implicated in fouling of nanofiltration and reverse osmosis membranes, either as the primary foulant or as a conditioning layer for microbial attachment ("biofouling"). In this work we investigated the effects of various metal ions on NOM aggregation in aqueous solutions, by a combination of dynamic light scattering (DLS), small angle neutron scattering (SANS) and large-scale molecular dynamics (MD) computer simulations. This allows a detailed molecular-scale statistical analysis of the size and the structural topology of metal-NOM aggregates. The DLS measurements show that Ca2+ ions present in a Suwannee River NOM (SRNOM) solution lead to the formation of a wide range of supramolecular structures with sizes between 100 and 1,000 nm. In contrast, Mg2+ and Na+ do not affect the aggregation of SRNOM as strongly. SANS data are inconclusive but indicate the presence of quite large (>50 nm) fractal particles formed presumably through a cluster-cluster aggregation. MD simulations confirm these observations and show that NOM can aggregate in aqueous solutions by two different mechanisms. On the one hand, NOM molecules can spontaneously aggregate by hydrogen bonding between their functional groups when only Na+ and Mg2+ are present as background cations. This promotes the formation of uniformly shaped NOM clusters. On the other hand, if Ca2+ ions are present in solution, they can more strongly bind two different NOM molecules by co-complexing the carboxylate groups, thus promoting the formation of longer linear and

  17. Modification and characterization of PET fibers for fast removal of Hg(II), Cu(II) and Co(II) metal 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)

    2013-04-15

    Highlights: ► PET fibers were graft copolymerized with acrylonitrile. ► Further modification was carried out through the reaction with hydrazine hydrate and then potassium thiocyanate. ► The resulted chelating fibers were characterized by various instrumental methods. ► The fibers were applied to remove Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} from aqueous solutions. -- Abstract: A new chelating fiber (PET-TSC) was prepared with PET for fast removal of Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} from water. Elemental analysis, SEM, BET surface area, {sup 13}C NMR, FTIR and X-ray diffraction spectra were used to characterize PET-TSC. The higher uptake capacity of the studied metal ions was observed at higher pH values. Kinetic study indicated that the adsorption of Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} followed the pseudo-second-order equation, suggesting chemical sorption as the rate-limiting step of the adsorption process. The best interpretation for the equilibrium data was given by Langmuir isotherm, and the maximum adsorption capacities were 120.02, 96.81 and 78.08 mg/g for Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} ions, respectively. 1 M HCl or 0.1 M EDTA could be used as effective eluant to desorb the Hg{sup 2+}, Cu{sup 2+} and Co{sup 2+} adsorbed by PET-TSC, and the adsorption capacity of PET-TSC for the three heavy metal ions could still be maintained at about 90% level at the 5th cycle. Accordingly, it is expected that PET-TSC could be used as a promising adsorbent for fast removal of heavy metal ions from water, and the present work also might provide a simple and effective method to reuse the waste PET fibers.

  18. Application of Hydrothermal and Non-Hydrothermal TiO2 Nanoporous Materials as New Adsorbents for Removal of Heavy Metal Ions from Aqueous System

    Directory of Open Access Journals (Sweden)

    Mansoor Anbia

    2016-06-01

    Full Text Available Hydrothermal and non-hydrothermal spherical TiO2 nanoporous with crystalline framework were prepared by sol-gel method. The Crystalline structures, morphologies and surface texturing of materials were determined by X-ray diffraction (XRD, scanning electron microscopy (SEM and N2 adsorption-desorption isotherms. The Hydrothermal spherical TiO2 nanoporous was found to have a narrow and strong pore size distribution peaks with average of 37.8 Å and pore volume of 0.41 cm3/g and the (Brunauer–Emmett–TellerBET specific surface area of 365 m2/g. Hydrothermal and non-hydrothermal spherical TiO2 nanoporous have been used as adsorbent to study of the adsorption behavior of Pb(II, Co(II and Ni(II ions from aqueous system in a batch system. Effect of equilibrium time on adsorption Pb(II, Co(II and Ni(II ions on these adsorbent was studied The results show that the shaking time 0.5 to 10h has no serious effect on the percentage of ions removal, and the adsorption is fast in all cases. The maximum uptake capacities of Hydrothermal and non-hydrothermal spherical TiO2 nanoporous was calculated. Both hydrothermal and non-hydrothermal TiO2 nanoporous materials were found to have very good potential as new adsorbents in removal of these ions. In batch systems the maximum uptake capacities of Pb(II, Ni(II and Co(II on the hydrothermal and non-hydrothermal TiO2 nanoporous materials was Co(II > Pb(II > Ni(II and Co(II > Ni(II > Pb(II, respectively.

  19. Progress of Ongoing NASA Lithium-Ion Cell Verification Testing for Aerospace Applications

    Science.gov (United States)

    McKissock, Barbara I.; Manzo, Michelle A.; Miller, Thomas B.; Reid, Concha M.; Bennett, William R.; Gemeiner, Russel

    2008-01-01

    A Lithium-ion Verification and Validation Program with the purpose to assess the capabilities of current aerospace lithium-ion (Li-ion) battery cells to perform in a low-earth-orbit (LEO) regime was initiated in 2002. This program involves extensive characterization and LEO life testing at ten different combinations of depth-of-discharge, temperature, and end-of-charge voltage. The test conditions selected for the life tests are defined as part of a statistically designed test matrix developed to determine the effects of operating conditions on performance and life of Li-ion cells. Results will be used to model and predict cell performance and degradation as a function of test operating conditions. Testing is being performed at the Naval Surface Warfare Center/Crane Division in Crane, Indiana. Testing was initiated in September 2004 with 40 Ah cells from Saft and 30 Ah cells from Lithion. The test program has been expanded with the addition of modules composed of 18650 cells from ABSL Power Solutions in April 2006 and the addition of 50 Ah cells from Mine Safety Appliances Co. (MSA) in June 2006. Preliminary results showing the average voltage and average available discharge capacity for the Saft and Lithion packs at the test conditions versus cycles are presented.

  20. Adsorption of heavy metal ion from aqueous solution by nickel oxide nano catalyst prepared by different methods

    Directory of Open Access Journals (Sweden)

    Amira M. Mahmoud

    2015-03-01

    Full Text Available Environmental pollution by heavy metal is arising as the most endangering tasks to both water sources and atmosphere quality today. The treatment of heavy metals is of special concern due to their recalcitrance and persistence in the environment. To limit the spread of the heavy metals within water sources, nickel oxide nanoparticles adsorbents were synthesized and characterized with the aim of removal of one of the aggressive heavy elements, namely; lead ions. Nano nickel oxide adsorbents were prepared using NaOH and oxalic acid dissolved in ethanol as precursors. The results indicated that adsorption capacity of Pb(II ion by NiO-org catalyst is favored than that prepared using NaOH as a precipitant. Nickel oxide nanoparticles prepared by the two methods were characterized structurally and chemically through XRD, DTA, TGA, BET and FT-IR. Affinity and efficiency sorption parameters of the solid nano NiO particles, such as; contact time, initial concentration of lead ions and the dosage of NiO nano catalyst and competitive adsorption behaviors were studied. The results showed that the first-order reaction law fit the reduction of lead ion, also showed good linear relationship with a correlation coefficient (R2 larger than 0.9.

  1. Theoretical analysis of aqueous solutions of mixed strong electrolytes by a smaller-ion shell electrostatic model.

    Science.gov (United States)

    Fraenkel, Dan

    2014-02-07

    In spite of the great importance of mixed electrolytes in science and technology, no compelling theoretical explanation has been offered yet for the thermodynamic behavior of such systems, such as their deviation from ideality and the variation of their excess functions with ionic composition and concentration. Using the newly introduced Smaller-ion Shell treatment - an extension of the Debye-Hückel theory to ions of dissimilar size (hence DH-SiS) - simple analytic mathematical expressions can be derived for the mean and single-ion activity coefficients of binary electrolyte components of ternary ionic systems. Such expressions are based on modifying the parallel DH-SiS equations for pure binary ionic systems, by adding to the three ion-size parameters - a (of counterions), b+ (of positive coions), and b- (of negative coions) - a fourth parameter. For the (+ + -) system, this is "b++," the contact distance between non-coion cations. b++ is derived from fits with experiment and, like the other b's, is constant at varying ion concentration and combination. Four case studies are presented: (1) HCl-NaCl-H2O, (2) HCl-NH4Cl-H2O, (3) (0.01 M HX)-MX-H2O with X = Cl, Br, and with M = Li, Na, K, Cs, and (4) HCl-MCln-H2O with n = 2, M = Sr, Ba; and n = 3, M = Al, Ce. In all cases, theory is fully consistent with experiment when using a of the measured binary electrolyte as the sole fitting parameter. DH-SiS is thus shown to explain known "mysteries" in the behavior of ternary electrolytes, including Harned rule, and to adequately predict the pH of acid solutions in which ionized salts are present at different concentrations.

  2. First test of BNL electron beam ion source with high current density electron beam

    Science.gov (United States)

    Pikin, Alexander; Alessi, James G.; Beebe, Edward N.; Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard

    2015-01-01

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm2 and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  3. Complete Transmetalation in a Metal-Organic Framework by Metal Ion Metathesis in a Single Crystal for Selective Sensing of Phosphate Ions in Aqueous Media.

    Science.gov (United States)

    Asha, K S; Bhattacharjee, Rameswar; Mandal, Sukhendu

    2016-09-12

    A complete transmetalation has been achieved on a barium metal-organic framework (MOF), leading to the isolation of a new Tb-MOF in a single-crystal (SC) to single-crystal (SC) fashion. It leads to the transformation of an anionic framework with cations in the pore to one that is neutral. The mechanistic studies proposed a core-shell metal exchange through dissociation of metal-ligand bonds. This Tb-MOF exhibits enhanced photoluminescence and acts as a selective sensor for phosphate anion in aqueous medium. Thus, this work not only provides a method to functionalize a MOF that can have potential application in sensing but also elucidates the formation mechanism of the resulting MOF.

  4. Fast, selective adsorption of Cu{sup 2+} from aqueous mixed metal ions solution using 1,4,7-triazacyclononane modified SBA-15 silica adsorbent (SBA-TACN)

    Energy Technology Data Exchange (ETDEWEB)

    Tapaswi, Pradip Kumar; Moorthy, Madhappan Santha; Park, Sung Soo; Ha, Chang-Sik, E-mail: csha@pnu.edu

    2014-03-15

    A new SBA-15 supported 1,4,7-triazacyclononane modified mesoporous silica adsorbent (SBA-TACN) has been synthesized using post grafting route and has thoroughly been characterized by small angle X-ray scattering (SAXS), N{sub 2} adsorption–desorption measurements, Fourier-transform infrared (FT-IR), solid-state {sup 29}Si MAS and {sup 13}C CP MAS NMR spectroscopy, transmission electron (TEM) and scanning electron microscopy (SEM), elemental analysis (EA) and thermogravimetric analysis (TGA). The synthesized material shows excellent copper (II) ion adsorption selectivity at pH 5 in mixed metal ion solution containing Cu{sup 2+}, Cr{sup 3+}, Ni{sup 2+}, Co{sup 2+} and Li{sup +}. The copper ion adsorption capacity of the SBA-TACN can reach a maximum value of 0.67 mmol/g. Possible adsorption mechanism of metal ions on SBA-TACN has been discussed. The adsorbent can be readily regenerated by HNO{sub 3}–NH{sub 3} treatment. -- Graphical abstract: A new SBA-15 supported 1,4,7-triazacyclononane (TACN) modified mesoporous silica (SBA-TACN) adsorbent has been developed which shows excellent selectivity in Cu{sup 2+} adsorption from aqueous mixed metal ion solutions at pH 5. The copper ion adsorption capacity of the SBA-TACN can reach a maximum value of 0.67 mmol/g. The adsobent is stable enough to be used atleast for three cycles. Highlights: • Synthesis of a new TACN modified mesoporous silica SBA-15 type adsorbent. • The density of 1,4,7-triazacyclononane on SBA-15 is 1.22 mmol/g. • First report on the selective Cu{sup 2+} adsorption by TACN modified mesoporous silica. • Cu{sup 2+} adsorption capacity of the SBA-TACN can reach a maximum value of 0.67 mmol/g. • Potential candidate for selective removal of Cu{sup 2+} from contaminated water samples.

  5. Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from Radio Frequency plasma) experiment: tests in BATMAN (BAvarian Test Machine for Negative ions).

    Science.gov (United States)

    Brombin, M; Spolaore, M; Serianni, G; Pomaro, N; Taliercio, C; Dalla Palma, M; Pasqualotto, R; Schiesko, L

    2014-11-01

    A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors' holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.

  6. Langmuir probes for SPIDER (source for the production of ions of deuterium extracted from radio frequency plasma) experiment: Tests in BATMAN (Bavarian test machine for negative ions)

    Energy Technology Data Exchange (ETDEWEB)

    Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Spolaore, M.; Serianni, G.; Pomaro, N.; Taliercio, C.; Palma, M. Dalla; Pasqualotto, R. [Consorzio RFX, Corso Stati Uniti 4, I-35127 Padova (Italy); Schiesko, L. [Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching (Germany)

    2014-11-15

    A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors’ holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.

  7. Langmuir probes for SPIDER (source for the production of ions of deuterium extracted from radio frequency plasma) experiment: Tests in BATMAN (Bavarian test machine for negative ions)

    Science.gov (United States)

    Brombin, M.; Spolaore, M.; Serianni, G.; Pomaro, N.; Taliercio, C.; Palma, M. Dalla; Pasqualotto, R.; Schiesko, L.

    2014-11-01

    A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors' holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.

  8. Determination of Stability Constants of Triazole Ligand Carrying Naphthol Group with Heavy Metal Ions in Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Nurhan Gümrükçüoğlu

    2013-12-01

    Full Text Available Interaction of 4-(2-hydroxy-1-naphthylmethylamino-3-methyl-5-(4-tolyl-4H-1,2,4-triazole with heavy metal cations such as Cu2+, Co2+, Cd2+, Ni2+ and Pb2+ was investigated by using UV-visible spectrophotometric technique. The complex stability constants (Log β were determined in aqueous as well as in methanol: water (1:1 system at 25 ± 0.1°C by Buschmann’s method and Valeur’s methods, respectively. The ligand showed good sensitivity for Co2+ with a linear range of 210-6M to 310-5M.

  9. Novel synthetic approach for 1, 4-dihydroxyanthraquinone and the development of its Lithiated salts as anode material for aqueous rechargeable Lithium-ion batteries

    KAUST Repository

    Gurukar, Suresh Shivappa

    2015-08-17

    The influence of organic electrode materials in the field of lithium ion battery is becoming a keen interest for the present generation scientists. Here we are reporting a novel method of synthesis of electrode material by the combination of sono-chemical and thermal methods. The advantages of organic active material towards lithium ion battery are of core interest of this study. The structural confirmations are by FT-IR, 1H NMR, MALDI-TOF Mass Spectroscopy and powder XRD data. The electrochemical properties of Lithiated-1,4-dihydroxyanthraquinone were studied using electrochemical-techniques such as Cyclic Voltammetry, Galvanostatic Cyclic Potential Limitation and Potentiostatic Electrochemical Impedance Spectroscopy. The satisfactory results towards stability of active species in the aqueous media, reasonable discharge capacity with 0.9 V average voltages and agreeable cycling performance during charge-discharge process with reproducibility are achieved. For the construction of the full cell, the anode material was coupled with the LiNi1/3Co1/3Mn1/3O2 as a cathode material.

  10. Method for The Removal of Piumbum(II Ion from Aqueous Solutions by Corn Cobas A Natural Adsorbent and from The View Point Thermodynamics

    Directory of Open Access Journals (Sweden)

    Gholamali Haghdoost

    2016-06-01

    Full Text Available Corn cob as a low-cost adsorbent were used in the present work for the removal of toxic heavy metal Pb2+ from aqueous solutions. Bath experiments were used to determine the best adsorption conditions. The equilibrium adsorption level was determined as a function of solution pH, temperature(T, contact time(tc, initial adsorbate concentration, and adsorbent dosage. Effective removal of metal ions was demonstrated at pH values of 6. Metal adsorption onto Corn cobwas evaluated by Langmuir and Freundlich isotherms. Results indicate that the Langmuir isotherm model is the most suitable one for the adsorption process using Corn cob(R2=0.9742, thus indicating the applicability of monolayer coverage of Pb(II ion on Corn cob surface.The relationship between thermodynamic parameters was used to predict the absorption process. According to Thermodynamic analysis, the process endothermic and natural (ΔHo=-16.2 Jmol-1 and ΔSo =- 59.71 Jmol-1 K-1.

  11. 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.

  12. Application of L-Aspartic Acid-Capped ZnS:Mn Colloidal Nanocrystals as a Photosensor for the Detection of Copper (II Ions in Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Jungho Heo

    2016-04-01

    Full Text Available Water-dispersible ZnS:Mn nanocrystals (NCs were synthesized by capping the surface with polar L-aspartic acid (Asp molecules. The obtained ZnS:Mn-Asp NC product was optically and physically characterized using the corresponding spectroscopic methods. The ultra violet-visible (UV-VIS absorption spectrum and photoluminescence (PL emission spectrum of the NCs showed broad peaks at 320 and 590 nm, respectively. The average particle size measured from the obtained high resolution-transmission electron microscopy (HR-TEM image was 5.25 nm, which was also in accordance with the Debye-Scherrer calculations using the X-ray diffraction (XRD data. Moreover, the surface charge and degree of aggregation of the ZnS:Mn-Asp NCs were determined by electrophoretic and hydrodynamic light scattering methods, respectively. These results indicated the formation of agglomerates in water with an average size of 19.8 nm, and a negative surface charge (−4.58 mV in water at ambient temperature. The negatively-charged NCs were applied as a photosensor for the detection of specific cations in aqueous solution. Accordingly, the ZnS:Mn-Asp NCs showed an exclusive luminescence quenching upon addition of copper (II cations. The kinetic mechanism study on the luminescence quenching of the NCs by the addition of the Cu2+ ions proposed an energy transfer through the ionic binding between the two oppositely-charged ZnS:Mn-Asp NCs and Cu2+ ions.

  13. Ultrasensitive and rapid screening of mercury(II) ions by dual labeling colorimetric method in aqueous samples and applications in mercury-poisoned animal tissues

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Yi; Wang, Xin; Xue, Feng [School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009 (China); Zheng, Lei [School of Medical Engineering, Hefei University of Technology, Hefei 230009 (China); Liu, Jian [School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009 (China); Yan, Feng [Applied Physics Department, Hong Kong Polytechnic University, Hong Kong (China); Xia, Fan, E-mail: xiafan@hust.edu.cn [School of Chemistry & Chemical Engineering, Huazhong University of Science & Technology, Wuhan 430074 (China); Chen, Wei, E-mail: chenweishnu@163.com [School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009 (China)

    2015-04-08

    Highlights: • Rapid and ultrasensitive screening of mercury ions are achieved by using gold nanoparticles based colorimetric method. • Dual labeling strategy is adopted for sensing signal amplification. • The proposed method is successfully used for analysis of mercury-poisoned animal tissues. - Abstract: Rapid and ultrasensitive detection of trace heavy metal mercury(II) ions (Hg{sup 2+}) are of significant importance due to the induced serious risks for environment and human health. This presented article reports the gold nanoparticle-based dual labeling colorimetric method (Dual-COLO) for ultrasensitive and rapid detection of Hg{sup 2+} using the specific thymine–Hg{sup 2+}–thymine (T–Hg{sup 2+}–T) as recognition system and the dual labeling strategy for signal amplification. Both qualitative and quantitative detections of Hg{sup 2+} are achieved successfully in aqueous samples. More importantly, the achieved detection limit of 0.005 ng mL{sup −1} (0.025 nM) without any instruments is very competitive to other rapid detection methods even ICP-MS based methods. This Dual-COLO method is also applied directly for real water sample monitoring and, more importantly, applied in analysis of mercury poisoned animal tissues and body fluidic samples, indicating a potentially powerful and promising tool for environmental monitoring and food safety control.

  14. One-pot fabrication of FRET-based fluorescent probe for detecting copper ion and sulfide anion in 100% aqueous media

    Science.gov (United States)

    Lv, Kun; Chen, Jian; Wang, Hong; Zhang, Peisheng; Yu, Maolin; Long, Yunfei; Yi, Pinggui

    2017-04-01

    The design of effective tools for detecting copper ion (Cu2 +) and sulfide anion (S2 -) is of great importance due to the abnormal level of Cu2 + and S2 - has been associated with an increase in risk of many diseases. Herein, we report on the fabrication of fluorescence resonance energy transfer (FRET) based fluorescent probe PF (PEI-FITC) for detecting Cu2 + and S2 - in 100% aqueous media via a facile one-pot method by covalent linking fluorescein isothiocyanate (FITC) with branched-polyethylenimine (b-PEI). PF could selectively coordinate with Cu2 + among 10 metal ions to form PF-Cu2 + complex, resulting in fluorescence quenching through FRET mechanism. Furthermore, the in situ generated PF-Cu2 + complex can be used to selectively detect S2 - based on the displacement approach, resulting in an off-on type sensing. There is no obvious interference from other anions, such as Cl-, NO3-, ClO4-, SO42 -, HCO3-, CO32 -, Br-, HPO42 -, F- and S2O32 -. In addition, PF was successfully used to determine Cu2 + and S2 - in human serum and tap water samples. Therefore, the FRET-based probe PF may provide a new method for selective detection of multifarious analysts in biological and environmental applications, and even hold promise for application in more complicated systems.

  15. Earliest Results in the Use of Activated Composite Membranes for the Transport of Silver Ions from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Yucundo Mendoza-Tolentino

    2014-01-01

    Full Text Available This paper presents the results concerning the first use of activated composite membranes (ACMs for the facilitated transport of silver ions containing di-(2-ethylhexyl-dithiophosphoric acid (DTPA as the carrier. DTPA was immobilized by interfacial polymerization in a dense layer that was deposited in a porous layer, which was prepared on a nonwoven fabric support by phase inversion. The influence of fundamental parameters affecting the transport of silver ion as the carrier concentration in the membrane phase and stripping agent variation of the stripping solution have been studied. In the optimal conditions, the amount of silver transported across the ACMs was greater than 50%, whereas if the content of the carrier is modified, more than the 90% of the initial silver is removed from the feed phase.

  16. Removal of Ni (II and Cr (VI ions from aqueous solution using by-product from the production of aluminium

    Directory of Open Access Journals (Sweden)

    A. Štrkalj

    2015-01-01

    Full Text Available In this paper comparative adsorption equilibrium studies of Ni (II and Cr (VI ions on commercial activated carbon (CAC and carbon anode dust (CAD are presented. The equilibrium studies confirmed that Freundlich model best describes the adsorption systems CAC + Cr (VI, CAD + Ni (II and CAD + Cr (VI. The Dubinin-Radushevich isotherm can be used to describe system CAC + Ni (II.The results indicate that the intra-particle diffusion model is applicable for adsorption system CAC + Cr (VI and pseudo-second kinetic model is applicable for adsorption systems CAC + Ni (II, CAD + Cr (VI and CAD + Ni (II. Obtained results indicate that adsorption of Ni (II and Cr (VI ions on CAC and CAD depends on the temperature.

  17. Femtosecond Laser-Induced Formation of Gold-Rich Nanoalloys from the Aqueous Mixture of Gold-Silver Ions

    Directory of Open Access Journals (Sweden)

    Yuliati Herbani

    2010-01-01

    Full Text Available The synthesis of gold-silver (AuAg nanoalloys of various compositions has been performed by direct irradiation of highly intense femtosecond laser pulse in the presence of polyvinylpyrrolidone (PVP. The mixture of Au and Ag ions of low concentration was simply introduced into a glass vial and subjected to femtosecond laser pulses for several minutes. The AuAg nanoalloys of 2-3 nm with reasonably narrow size distribution were formed, and the position of the surface plasmon resonance (SPR increased monotonically with an increase in the gold molar fraction in the ion solutions. The high resolution transmission electron microscope (HRTEM images exhibited the absence of core-shell structures, and the energy dispersive X-ray spectroscopy (EDX analysis confirmed that the particles were Au-rich alloys even for the samples with large fraction of Ag+ ions fed in the solution mixture. The formation mechanism of the alloy nanoparticles in the high intensity optical field was also discussed.

  18. Oxidation of atrazine in aqueous media by solar- enhanced Fenton-like process involving persulfate and ferrous ion.

    Science.gov (United States)

    Khandarkhaeva, Marina; Batoeva, Agniya; Aseev, Denis; Sizykh, Marina; Tsydenova, Oyuna

    2017-03-01

    The oxidation of s-triazines (using atrazine (ATZ) as a model compound) by a solar-enhanced Fenton-like process involving persulfate and ferrous ion was studied. A flow-through tubular photoreactor was employed for the experiments. The solar-enhanced oxidative system involving ferrous ion and persulfate (Solar/S2O8(2-)/Fe(2+)) showed the highest ATZ degradation efficiency when compared with other treatments (unactivated S2O8(2-), Solar - sunlight only, S2O8(2-)/Fe(2+), Solar/S2O8(2-)). Complete degradation of ATZ and 20% reduction in total organic carbon (TOC) content were observed after 30min of the treatment. The in situ generated (•)ОН and SO4(-•) radicals were shown to be involved in ATZ oxidation using the radical scavengers methanol and tert-butyl alcohol. Furthermore, iron compounds were shown to act not only as catalysts but also as photo-sensitizers, as the introduction of ferrous ion into the reaction mixture led to an increased absorbance of the solution and expansion of the absorption spectrum into the longer wavelength spectral region.

  19. Magnified fluorescence detection of silver(I) ion in aqueous solutions by using nano-graphite-DNA hybrid and DNase I.

    Science.gov (United States)

    Wei, Yin; Li, Bianmiao; Wang, Xu; Duan, Yixiang

    2014-08-15

    This paper describes a novel approach utilizing nano-graphite-DNA hybrid and DNase I for the amplified detection of silver(I) ion in aqueous solutions for the first time. Nano-graphite can effectively quench the fluorescence of dye-labeled cytosine-rich single-stranded DNA due to its strong π-π stacking interactions; however, in the presence of Ag(+), C-Ag(+)-C coordination induces the probe to fold into a hairpin structure, which does not adsorb on the surface of nano-graphite and thus retains the dye fluorescence. Meanwhile, the hairpin structure can be cleaved by DNase I, and in such case Ag(+) is delivered from the complex. The released Ag(+) then binds other dye-labeled single-stranded DNA on the nano-graphite surface, and touches off another target recycling, resulting in the successive release of dye-labeled single-stranded DNA from the nano-graphite, which leads to significant amplification of the signal. The present magnification sensing system exhibits high sensitivity toward Ag(+) with a limit of detection of 0.3nM (S/N=3), which is much lower than the standard for Ag(+) in drinking water recommended by the Environmental Protection Agency (EPA). The selectivity of the sensor for Ag(+) against other biologically and environmentally related metal ions is outstanding due to the high specificity of C-Ag(+)-C formation. Moreover, the sensing system is used for the determination of Ag(+) in river water samples with satisfying results. The proposed assay is simple, cost-effective, and might open the door for the development of new assays for other metal ions or biomolecules.

  20. Heat-transfer tests of aqueous ethylene glycol solutions in an electrically heated tube

    Science.gov (United States)

    Bernardo, Everett; Eian, Carroll S

    1945-01-01

    As part of an investigation of the cooling characteristics of liquid-cooled engines, tests were conducted with an electrically heated single-tube heat exchanger to determine the heat-transfer characteristics of an-e-2 ethylene glycol and other ethylene glycol-water mixtures. Similar tests were conducted with water and commercial butanol (n-butyl alcohol) for check purposes. The results of tests conducted at an approximately constant liquid-flow rate of 0.67 pound per second (Reynolds number, 14,500 to 112,500) indicate that at an average liquid temperature 200 degrees f, the heat-transfer coefficients obtained using water, nominal (by volume) 30 percent-70 percent and 70 percent-30 percent glycol-water mixtures are approximately 3.8, 2.8, and 1.4 times higher, respectively, than the heat-transfer coefficients obtained using an-e-2 ethylene glycol.

  1. Selectivity of the highly preorganized tetradentate ligand 2,9-di(pyrid-2-yl)-1,10-phenanthroline for metal ions in aqueous solution, including lanthanide(III) ions and the uranyl(VI) cation.

    Science.gov (United States)

    Carolan, Ashley N; Cockrell, Gregory M; Williams, Neil J; Zhang, Gang; VanDerveer, Donald G; Lee, Hee-Seung; Thummel, Randolph P; Hancock, Robert D

    2013-01-01

    Some metal ion complexing properties of DPP (2,9-Di(pyrid-2-yl)-1,10-phenanthroline) are reported with a variety of Ln(III) (Lanthanide(III)) ions and alkali earth metal ions, as well as the uranyl(VI) cation. The intense π-π* transitions in the absorption spectra of aqueous solutions of 10(-5) M DPP were monitored as a function of pH and metal ion concentration to determine formation constants of the alkali-earth metal ions and Ln(III) (Ln = lanthanide) ions. It was found that log K(1)(DPP) for the Ln(III) ions has a peak at Ln(III) = Sm(III) in a plot of log K(1) versus 1/r(+) (r(+) = ionic radius for 8-coordination). For Ln(III) ions larger than Sm(III), there is a steady rise in log K(1) from La(III) to Sm(III), while for Ln(III) ions smaller than Sm(III), log K(1) decreases slightly to the smallest Ln(III) ion, Lu(III). This pattern of variation of log K(1) with varying size of Ln(III) ion was analyzed using MM (molecular mechanics) and DFT (density functional theory) calculations. Values of strain energy (∑U) were calculated for the [Ln(DPP)(H(2)O)(5)](3+) and [Ln(qpy)(H(2)O)(5)](3+) (qpy = quaterpyrdine) complexes of all the Ln(III) ions. The ideal M-N bond lengths used for the Ln(III) ions were the average of those found in the CSD (Cambridge Structural Database) for the complexes of each of the Ln(III) ions with polypyridyl ligands. Similarly, the ideal M-O bond lengths were those for complexes of the Ln(III) ions with coordinated aqua ligands in the CSD. The MM calculations suggested that in a plot of ∑U versus ideal M-N length, a minimum in ∑U occurred at Pm(III), adjacent in the series to Sm(III). The significance of this result is that (1) MM calculations suggest that a similar metal ion size preference will occur for all polypyridyl-type ligands, including those containing triazine groups, that are being developed as solvent extractants in the separation of Am(III) and Ln(III) ions in the treatment of nuclear waste, and (2) Am(III) is very

  2. Turbulent mix or ion diffusion? Hypothesis testing in ICF capsule implosions

    Science.gov (United States)

    Hoffman, N. M.; Zimmerman, G. B.; Vander Wiel, S. A.; Herrmann, H. W.; Kim, Y. H.

    2016-10-01

    Turbulent mixing at a contact surface combines materials that are initially separated across the contact. While the mixing layer may contain the initially separate materials (each assumed to be composed of a number of distinct ion species) in a range of concentrations, from zero to 100%, the concentration of individual ion species within each material, relative to one another, is not altered by turbulent mixing alone. Ion diffusion likewise causes mixing at a contact, but does alter the relative concentration of ion species within each material, since the relative diffusivity of ions, in a fixed background plasma, varies as A 1 / 2/Z2. Recent hydrodynamically equivalent capsule implosions allow a test of the influence of these processes on observed capsule behavior. We use numerical simulations and hypothesis-testing methods to show quantitatively that turbulent mixing with ion diffusion is a better explanation of observed behavior than turbulent mixing alone (subject to the assumptions inherent in the computational models of these processes.) Research supported by US DOE under contract DE-AC52-06NA25396.

  3. DNA derived fluorescent bio-dots for sensitive detection of mercury and silver ions in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ting [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhu, Xuefeng, E-mail: zhuxf@ms.xjb.ac.cn [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Zhou, Shenghai [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Yang, Guang [Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education and International Center for Dielectric Research, Xi’an Jiaotong University, Xi’an 710049 (China); Gan, Wei [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China); Yuan, Qunhui, E-mail: yuanqh@ms.xjb.ac.cn [Laboratory of Environmental Science and Technology, Xinjiang Technical Institute of Physics & Chemistry, Key Laboratory of Functional Materials and Devices for Special Environments, Chinese Academy of Sciences, Urumqi 830011 (China)

    2015-08-30

    Highlights: • First application of a DNA derived fluorescent bio-dot for metal sensing. • Bio-dot was conveniently obtained via a mild thermal hydro-thermal synthesis. • Bio-dot was directly used for fluorescent sensing without further modification. • Bio-dot showed good fluorescent sensing property for Hg(II) and Ag(I). • Formation of T–Hg–T and C–Ag–C structures played key roles in sensing. - Abstract: Inspired by the high affinity between heavy metal ions and bio-molecules as well as the low toxicity of carbon-based quantum dots, we demonstrated the first application of a DNA derived carbonaceous quantum dots, namely bio-dots, in metal ion sensing. The present DNA-derived bio-dots contain graphitic carbon layers with 0.242 nm lattice fringes, exhibit excellent fluorescence property and can be obtained via a facile hydrothermal preparation procedure. Hg(II) and Ag(I) are prone to be captured by the bio-dots due to the existence of residual thymine (T) and cytosine (C) groups, resulting in a quenched fluorescence while other heavy metal ions would cause negligible changes on the fluorescent signals of the bio-dots. The bio-dots could be used as highly selective toxic-free biosensors, with two detecting linear ranges of 0–0.5 μM and 0.5–6 μM for Hg(II) and one linear range of 0–10 μM for Ag(I). The detection limits (at a signal-to-noise ratio of 3) were estimated to be 48 nM for Hg(II) and 0.31 μM for Ag(I), respectively. The detection of Hg(II) and Ag(I) could also be realized in the real water sample analyses, with satisfying recoveries ranging from 87% to 100%.

  4. KINETICS AND EQUILIBRIUM PARAMETERS OF BIOSORPTION AND BIOACCUMULATION OF LEAD IONS FROM AQUEOUS SOLUTIONS BY TRICHODERMA LONGIBRACHIATUM

    Directory of Open Access Journals (Sweden)

    Enitan S. Balogun

    2012-04-01

    Full Text Available Biosorption and bioaccumulation of Lead ions (Pb(II by Trichoderma longibrachiatum were investigated in a batch system. The effects of some important parameters such as pH, initial metal concentration, temperature and inoculum concerntration on biosorption capacity were also studied. The maximum biosorption capacity of Trichoderma longibrachiatum was at 25 ppm of lead, showed 100 % removal at pH 7 and 25 oC after fifteen days. Biosorption equilibrium was established in 150 minutes. The process fitted well into pseudo second order kinetic model and was best explained by Langmuir isotherm.

  5. The preliminary tests of the superconducting electron cyclotron resonance ion source DECRIS-SC2.

    Science.gov (United States)

    Efremov, A; Bekhterev, V; Bogomolov, S; Drobin, V; Loginov, V; Lebedev, A; Yazvitsky, N; Yakovlev, B

    2012-02-01

    A new compact version of the "liquid He-free" superconducting ECR ion source, to be used as an injector of highly charged heavy ions for the MC-400 cyclotron, is designed and built at the Flerov Laboratory of Nuclear Reactions in collaboration with the Laboratory of High Energy Physics of JINR. The axial magnetic field of the source is created by the superconducting magnet and the NdFeB hexapole is used for the radial plasma confinement. The microwave frequency of 14 GHz is used for ECR plasma heating. During the first tests, the source shows a good enough performance for the production of medium charge state ions. In this paper, we will present the design parameters and the preliminary results with gaseous ions.

  6. Wave-particle resonance condition test for ion-kinetic waves in the solar wind

    Science.gov (United States)

    Narita, Y.; Marsch, E.; Perschke, C.; Glassmeier, K.-H.; Motschmann, U.; Comişel, H.

    2016-04-01

    Conditions for the Landau and cyclotron resonances are tested for 543 waves (identified as local peaks in the energy spectra) in the magnetic field fluctuations of the solar wind measured by the Cluster spacecraft on a tetrahedral scale of 100 km. The resonance parameters are evaluated using the frequencies in the plasma rest frame, the parallel components of the wavevectors, the ion cyclotron frequency, and the ion thermal speed. The observed waves show a character of the sideband waves associated with the ion Bernstein mode, and are in a weak agreement with the fundamental electron cyclotron resonance in spite of the ion-kinetic scales. The electron cyclotron resonance is likely taking place in solar wind turbulence near 1 AU (astronomical unit).

  7. Ion conduction mechanism in non-aqueous polymer electrolytes based on oxalic acid: Effect of plasticizer and polymer

    Energy Technology Data Exchange (ETDEWEB)

    Missan, Harinder Pal Singh; Chu, P.P. [Department of Chemistry, National Central University, Chungli 32001 (Taiwan); Sekhon, S.S. [Department of Applied Physics, Guru Nanak Dev University, Amritsar, Punjab 143005 (India)

    2006-08-25

    Non-aqueous proton-conducting polymer electrolytes in the film form are synthesized through the complexation of oxalic acid (OA) and polyvinylidenefluoride-co-hexafluoro propylene (PVdF-HFP). Interestingly, the addition of a small amount of the basic component dimethylacetamide (DMA) gives rise to a three-order increase in conductivity. The value is found to depend on the concentrations of the weak acid and DMA in the electrolytes. A maximum conductivity of 0.12x10{sup -3}Scm{sup -1} has been achieved at ambient temperature for electrolytes containing 40wt.% OA with DMA. The observed increase in conductivity is considered to be due to interactions taking place between the high dielectric polymer media, the acid and the basic plasticizer. These interactions are confirmed from fourier transform infra red (FTIR) studies and supported by differential scanning calorimetry (DSC) measurements. Apart from providing acid-base interaction, the base DMA also improves the surface morphology and reduces the pore volume, both of which help to retain the acid-base complex within the membrane. (author)

  8. Single step synthesis of amine-functionalized mesoporous magnetite nanoparticles and their application for copper ions removal from aqueous solution.

    Science.gov (United States)

    Gao, Jining; He, Yingjuan; Zhao, Xianying; Ran, Xinze; Wu, Yonghui; Su, Yongping; Dai, Jianwu

    2016-11-01

    Amine-functionalized mesoporous superparamagnetic Fe3O4 nanoparticles with an average size of 70nm have been synthesized using a single step solvothermal method by the introduction of triethylenetetramine (TETA), a chelating agent recommended for the removal of excess copper in patients with Wilson's disease. The synthesized nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, nitrogen adsorption/desorption isotherm, vibrating sample magnetometer (VSM), and Fourier transform infrared spectroscopy (FTIR). It is confirmed that the magnetic nanoparticles have been functionalized with TETA during the synthetic process, and the concentration of TETA is crucial for the formation of monodisperse mesoporous nanoparticles. The obtained single-crystal magnetic nanoparticles have a high magnetization, which enhances their response to external magnetic field and therefore should greatly facilitate the manipulation of the particles in practical uses. Reaction parameters affecting the formation of mesoporous structure were explored, and a possible formation mechanism involving templated aggregation and recrystallization processes was proposed. The capacity of the synthesized amine-functionalized Fe3O4 nanoparticles toward Cu(II) removal from aqueous solution was investigated. The adsorption rate of Cu(II) on amine-functionalized Fe3O4 nanoparticles followed a pseudo-second order kinetic model. The results of this study demonstrated that the amine-functionalized mesoporous superparamagnetic Fe3O4 nanoparticles could be used as an efficient adsorbent in water treatment and would also find potential application for Cu(II) removal in vivo.

  9. Flame Atomic Absorption Determination of Gold Ion in Aqueous Samples after Preconcentration Using 9-Acridinylamine Functionalized γ-Alumina Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mohammad Karimi

    2013-01-01

    Full Text Available A simple and sensitive solid phase extraction utilizing 9-acridinylamine functionalized alumina nanoparticles was developed, and their potential use for preconcentration and subsequent determination of gold by flame atomic absorption spectrometry (FAAS was investigated. A number of parameters, namely, type, concentration, and volume of eluent, pH of the sample solution, flow rate of extraction, and volume of the sample, were evaluated. The effect of a variety of ions on preconcentration and recovery was also investigated. Gold ions were found to be recovered quantitatively at pH 3.0, with 0.1 mol L−1 thiourea in 2 mol L−1 H2SO4 as eluent. The limit of detection (LOD, defined as five times the standard deviation of the blank, was determined to be lower than 13.0 ppb. Under optimum conditions, the accuracy and precision (RSD% of the method were >98.0 and <1.5%, respectively. To gauge its ability in terms of application to real samples, the proposed method was successfully applied for determination of gold concentration in waste water samples and one soil standard material, and satisfactory results were obtained.

  10. Recovery and reuse of hexavalent chromium from aqueous solutions by a hybrid technique of electrodialysis and ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Gayathri, R. [Sengunthar Engineering College, Tiruchengode (India). Dept. of Civil Engineering], e-mail: gay3civil@gmail.com; Senthil Kumar, P. [SSN College of Engineering, Chennai (India). Dept. of Chemical Engineering], E-mail: senthilkumarp@ssn.edu.in

    2010-01-15

    The chrome plating industry is one of the highly polluting industries whose effluent mainly consists of chromium(VI). This compound is highly toxic to aquatic life and human health. The rinse water constituents reflect the chrome plating bath characteristics; generally dead tank wash water contains about 1% of the plating bath concentration. Other metals and metal compounds usually considered as toxic can be precipitated out by suitably adjusting the pH of the wastewaters. However, Cr(VI) is soluble in almost all pH ranges and therefore an efficient treatment is required for the removal and recovery of chromium, and also for the reuse of wastewaters. The present study aims to recover the chromium by a hybrid technique of electrodialysis and ion exchange for the removal and concentration of chromate ions from the effluent. The different modes of operation like batch recirculation process, batch recirculation process with continuous dipping and continuous process were carried out to remove and recover the chromium from the effluent and the percentage reductions of chromium were found to be 98.69%, 99.18% and 100%, respectively. (author)

  11. Bioinspired, direct synthesis of aqueous CdSe quantum dots for high-sensitive copper(II) ion detection.

    Science.gov (United States)

    Bu, Xiaohai; Zhou, Yuming; He, Man; Chen, Zhenjie; Zhang, Tao

    2013-11-21

    Luminescent CdSe semiconductor quantum dots (QDs), which are coated with a denatured bovine serum albumin (dBSA) shell, have been directly synthesized via a bioinspired approach. The dBSA coated CdSe QDs are ultrasmall (d CdSe QDs. The luminescent QDs are used for copper(II) ion detection due to their highly sensitive and selective fluorescence quenching response to Cu(2+). The concentration dependence of the quenching effect can be best described by the typical Stern-Volmer equation in a linearly proportional concentration of Cu(2+) ranging from 10 nM to 7.5 μM with a detection limit of 5 nM. As confirmed by various characterization results, a possible quenching mechanism is given: Cu(2+) ions are first reduced to Cu(+) by the dBSA shell and then chemical displacement between Cu(+) and Cd(2+) is performed at the surface of the ultrasmall metallic core to impact the fluorescence performance.

  12. Magnetically recoverable Fe3O4/graphene nanocomposite towards efficient removal of triazine pesticides from aqueous solution: Investigation of the adsorption phenomenon and specific ion effect.

    Science.gov (United States)

    Boruah, Purna K; Sharma, Bhagyasmeeta; Hussain, Najrul; Das, Manash R

    2017-02-01

    Spillage of effluents containing high concentration levels of pesticides into water has been considered as one of the serious environmental problems. In this study Fe3O4/reduced graphene oxide (rGO) nanocomposite has been efficiently utilized for the adsorption of five harmful pesticides namely ametryn, prometryn, simazine, simeton and atrazine in an aqueous medium. Electrostatic interaction between the pesticides and Fe3O4/rGO nanocomposite was analyzed by the zeta potential analysis, which is strongly related to the adsorption capacity of the adsorbent. The kinetics parameters of adsorption followed the pseudo second-order linear model. The adsorption isotherm studies show that, the maximum adsorption capacity of 54.8 mg g(-1) is achieved at pH 5 and it was enhanced in the presence of different ions (Mg(2+), Ca(2+), Na(+) and SO4(2)) and maximum (63.7 mg g(-1)) for ametryn adsorption was found in seawater medium. Thermodynamic parameter shows that, the adsorption process is physisorption and spontaneity in nature. The mechanism of the adsorption process was established by the DRIFT spectroscopy analysis. Efficient adsorption (93.61%) of pesticides was observed due to electrostatic, hydrophobic and π-π interactions of composite towards the heterocyclic conjugation of pesticide molecules. Further, Fe3O4/rGO nanocomposite was easily and rapidly separated from an aqueous medium using the external magnet for reuse and 88.66% adsorption efficiency was observed up to seven cycles.

  13. Photocatalytic degradation of methylene blue dye from aqueous solution using silver ion-doped TiO₂ and its application to the degradation of real textile wastewater.

    Science.gov (United States)

    Sahoo, Chittaranjan; Gupta, Ashok K; Sasidharan Pillai, Indu M

    2012-01-01

    Methylene blue dye (MB) was degraded photocatalytically in aqueous solution using Ag(+) doped TiO(2) under UV irradiation. The degradations of the dye using untreated TiO(2) and Ag(+) doped TiO(2) were compared. Ag(+) doped TiO(2) was found to be more efficient. Using Ag(+) doped TiO(2) the filtration process was eliminated, as the particles became more settleable. The effect of various parameters such as catalyst loading, initial dye concentration, depth of solution, degree of adsorption, pH and O(2) on dye degradation was studied. The extent of mineralization was studied by observing the COD removal at different time intervals. The effects of various interfering ions such as Cl(-), NO(3) (-), CO(3) (2-), SO(4) (2-), Ca(2+) and Fe(3+) and electron acceptors such as H(2)O(2), KBrO(3) and (NH(4))(2)S(2)O(8) on the dye degradation was also studied. The degradation kinetics fitted well to Langmuir-Hinshelwood pseudo first order rate law. An aqueous solution of MB (20ppm) degraded by more than 99% after UV irradiation for 180 min with Ag(+) doped TiO(2) (2 g/L) and by more than 95% with untreated TiO(2) (2 g/L)(.) The COD removal was more than 91% with Ag(+)doped TiO(2) and more than 86% with untreated TiO(2) after 240 min. The degradation and COD removal of 5 times diluted textile wastewater was more than 98% and 79% respectively with 1 g/L Ag(+) doped TiO(2) after UV irradiation for 420 min.

  14. In situ nanomechanical testing in focused ion beam and scanning electron microscopes

    Energy Technology Data Exchange (ETDEWEB)

    Gianola, D. S. [Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Institute for Applied Materials, Karlsruhe Institute of Technology, Karlsruhe (Germany); Sedlmayr, A.; Moenig, R.; Kraft, O. [Institute for Applied Materials, Karlsruhe Institute of Technology, Karlsruhe (Germany); Volkert, C. A. [Institute for Materials Physics, Georg-August University of Goettingen, Goettingen (Germany); Major, R. C.; Cyrankowski, E.; Asif, S. A. S.; Warren, O. L. [Hysitron, Inc., Minneapolis, Minnesota 55344 (United States)

    2011-06-15

    The recent interest in size-dependent deformation of micro- and nanoscale materials has paralleled both technological miniaturization and advancements in imaging and small-scale mechanical testing methods. Here we describe a quantitative in situ nanomechanical testing approach adapted to a dual-beam focused ion beam and scanning electron microscope. A transducer based on a three-plate capacitor system is used for high-fidelity force and displacement measurements. Specimen manipulation, transfer, and alignment are performed using a manipulator, independently controlled positioners, and the focused ion beam. Gripping of specimens is achieved using electron-beam assisted Pt-organic deposition. Local strain measurements are obtained using digital image correlation of electron images taken during testing. Examples showing results for tensile testing of single-crystalline metallic nanowires and compression of nanoporous Au pillars will be presented in the context of size effects on mechanical behavior and highlight some of the challenges of conducting nanomechanical testing in vacuum environments.

  15. In situ nanomechanical testing in focused ion beam and scanning electron microscopes.

    Science.gov (United States)

    Gianola, D S; Sedlmayr, A; Mönig, R; Volkert, C A; Major, R C; Cyrankowski, E; Asif, S A S; Warren, O L; Kraft, O

    2011-06-01

    The recent interest in size-dependent deformation of micro- and nanoscale materials has paralleled both technological miniaturization and advancements in imaging and small-scale mechanical testing methods. Here we describe a quantitative in situ nanomechanical testing approach adapted to a dual-beam focused ion beam and scanning electron microscope. A transducer based on a three-plate capacitor system is used for high-fidelity force and displacement measurements. Specimen manipulation, transfer, and alignment are performed using a manipulator, independently controlled positioners, and the focused ion beam. Gripping of specimens is achieved using electron-beam assisted Pt-organic deposition. Local strain measurements are obtained using digital image correlation of electron images taken during testing. Examples showing results for tensile testing of single-crystalline metallic nanowires and compression of nanoporous Au pillars will be presented in the context of size effects on mechanical behavior and highlight some of the challenges of conducting nanomechanical testing in vacuum environments.

  16. Tracer test for the measurement of gas diffusion and non-aqueous phase liquid (NAPL) saturation in soil.

    Science.gov (United States)

    Van De Steene, Joke; Höhener, Patrick

    2009-01-01

    During soil bioremediation, the diffusion of oxygen into the soil is an important prerequisite for aerobic biodegradation, and the decrease of petroleum products is the ultimate goal. Both processes need to be monitored. The aim of this work was to develop a gas tracer test that yields information on both, gas diffusion and residual saturation with non-aqueous phase liquids (NAPLs) in unsaturated soil heaps. One conservative tracer (methane) and 4 partitioning gas tracers (diethylether, methyl tert-butyl ether, chloroform and n-heptane) were injected as vapors into laboratory columns filled with unsaturated sand with increasing NAPL saturation. Breakthrough curves of gaseous compounds were measured at two points and compared to analytical solutions of an analytical diffusive-reactive transport equation. By fitting of methane data, robust results for effective diffusivity (tortuosity) were obtained. NAPL saturation was most accurately measured by the moderately water soluble tracers (ethers and chloroform). The hydrophobic tracer n-heptane did not partition into water-immersed NAPL. An easy and accurate way to assess air-NAPL partitioning constants from gas chromatography retention times is furthermore reported. It is concluded that gas tracer tests have the potential for measuring two important properties in soil bioremediation systems easily and quickly.

  17. One step synthesis of silver nanorods by autoreduction of aqueous silver ions with hydroxyapatite: An inorganic-inorganic hybrid nanocomposite.

    Science.gov (United States)

    Arumugam, Sujatha K; Sastry, Thotapalli Parvathaleswara; Sreedhar, B; Mandal, Asit Baran

    2007-02-01

    In this report, a novel method for the synthesis of silver nanoparticles on the surface of hydroxyapatite is described. Hydroxyapatite crystals are synthesized from acid mineralized solution, a byproduct of bone glue industries, by a simple chemical precipitation method, which results in the formation of hydroxyapatite nanocrystals. The reduction of silver ions occurs by the electron transfer from the hydroxyl groups on the surface of hydroxyapatite. This results in the formation of silver nanorods and needle shaped nanoparticles that are bound on the surface of hydroxyapatite, and the observed silver nanocrystals show anisotropic structure. Thus, hydroxyapatite crystals can be used as a new class of inorganic scaffolds for the synthesis of nanomaterials with implications in designing inorganic-inorganic hybrid nanocomposites for different applications.

  18. Removal of bisphenol A from aqueous solution by a dodecylsulfate ion-intercalated hydrotalcite-like compound.

    Science.gov (United States)

    Li, Yan; Bi, Hao-Yu; Shen, Shuang-Long

    2012-06-01

    A Mg-Al hydrotalcite-like compound (HTlc) and a dodecylsufate ion-intercalated Mg-Al HTlc (MHTlc) were prepared. The effects of temperature, ionic strength, and initial pH on the adsorptions ofbisphenol A (BPA) on both HTlc and MHTlc were studied in detail. The adsorption capacity of the pristine HTlc for BPA was low, and the adsorption was due to the substitution of surface anions within the pristine HTlc by the hydroxybenzene anion that was dissociated from BPA. The adsorption capacity for BPA increased notably with modification. The high adsorption capacity of MHTlc for BPA was mainly due to the dissolution of BPA molecules into the hydrophobic organic phase formed in the interlayers of MHTlc. The adsorption capacity of MHTlc for BPA decreased with increasing temperature and initial pH, but increased when increasing the ionic strength.

  19. Development and testing of ion exchangers for treatment of liquid wastes at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Collins, J.L.; Davidson, D.J.; Chase, C.W.; Egan, B.Z. (Oak Ridge National Lab., TN (United States)); Ensor, D.D.; Bright, R.M.; Glasgow, D.C. (Tennessee Technological Univ., Cookeville, TN (United States))

    1993-03-01

    This report addresses three areas of waste treatment: (1) treatment of newly generated low-level liquid waste and Melton Valley Storage Tank (MVST) supernate using inorganic ion exchangers; (2) treatment of processing streams at the Radiochemical Engineering Development Center (REDC); and (3) removal of radionuclides from organic solutions. Distribution of various radionuclides between simulated waste solutions and several sorbents was determined in batch tests. Inorganic ion exchangers were prepared in the form of microspheres by an intemal gelation process. Microspheres of hydrous titania, hydrous zirconia, hydrous titania containing embedded sodium cobalt hexacyanoferrate, and the corresponding phosphate forms of these materials were prepared. Several zeolites (PDZ-140, PDZ-300, EE-96, CBV-10A) and inorganic ion exchangers (hydrous titania, hydrous zirconia, polyantimanic acid, sodium cobalt hexacyanoferrate) were tested for the removal of cesium and strontium from the acidic simulated Cleanex raffinate generated at REDC. A resorcinol-based ion-exchange resin and three types of sodium titanate were tested for removal of cesium and strontium from the REDC caustic dissolver solution. Hydrous titania, hydrous zirconia, and their corresponding phosphates were tested for the removal of Eu[sup 3+] from various solutions of di-2-ethylbexyl phosphoric acid (HDEHP) in toluene or dodecane.

  20. Development and testing of ion exchangers for treatment of liquid wastes at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Collins, J.L.; Davidson, D.J.; Chase, C.W.; Egan, B.Z. [Oak Ridge National Lab., TN (United States); Ensor, D.D.; Bright, R.M.; Glasgow, D.C. [Tennessee Technological Univ., Cookeville, TN (United States)

    1993-03-01

    This report addresses three areas of waste treatment: (1) treatment of newly generated low-level liquid waste and Melton Valley Storage Tank (MVST) supernate using inorganic ion exchangers; (2) treatment of processing streams at the Radiochemical Engineering Development Center (REDC); and (3) removal of radionuclides from organic solutions. Distribution of various radionuclides between simulated waste solutions and several sorbents was determined in batch tests. Inorganic ion exchangers were prepared in the form of microspheres by an intemal gelation process. Microspheres of hydrous titania, hydrous zirconia, hydrous titania containing embedded sodium cobalt hexacyanoferrate, and the corresponding phosphate forms of these materials were prepared. Several zeolites (PDZ-140, PDZ-300, EE-96, CBV-10A) and inorganic ion exchangers (hydrous titania, hydrous zirconia, polyantimanic acid, sodium cobalt hexacyanoferrate) were tested for the removal of cesium and strontium from the acidic simulated Cleanex raffinate generated at REDC. A resorcinol-based ion-exchange resin and three types of sodium titanate were tested for removal of cesium and strontium from the REDC caustic dissolver solution. Hydrous titania, hydrous zirconia, and their corresponding phosphates were tested for the removal of Eu{sup 3+} from various solutions of di-2-ethylbexyl phosphoric acid (HDEHP) in toluene or dodecane.

  1. Performance and Safety Tests on Samsung 18650 Li-ion Cells with Two Capacities

    Science.gov (United States)

    Deng, Yi; Jeevarajan, Judith; Rehm, Raymond; Bragg, Bobby; Zhang, Wenlin

    2001-01-01

    In order to meet the applications for Space Shuttle in the future, Samsung 18650 cylindrical Li-ion cells with two different capacities have been evaluated. The capacities are 1800 mAh, and 2000 mAh. The studies focused on the performance and safety tests of the cells.

  2. Fracture tests of etched components using a focused ion beam machine

    Science.gov (United States)

    Kuhn, Jonathan L.; Fettig, Rainer K.; Moseley, Samuel H., Jr.; Kutyrev, Alexander S.; Orloff, Jon

    2000-08-01

    Many optical MEMS device designs involve large arrays of thin (0.5 to 1 (mu) m) components subjected to high stresses due to cyclic loading. These devices are fabricated from a variety of materials, and the properties strongly depend on size and processing. Our objective is to develop standard and convenient test methods that can be used to measure the properties of large numbers of witness samples, for every device we build. In this work we explore a variety of fracture tests configurations for 0.5 (mu) m thick silicon nitride membranes machined using the Reactive Ion Etching (RIE) process. Testing was completed using an FEI 620 dual focused ion beam milling machine. Static loads were applied using a probe, and dynamic loads were applied through a piezo-electric stack mounted at the base of the probe. Results from the tests are presented and compared, and application for predicting fracture probability of large arrays of devices are considered.

  3. Layer-by-layer encapsulated nano-emulsion of ionic liquid loaded with functional material for extraction of Cd(2+) ions from aqueous solutions.

    Science.gov (United States)

    Elizarova, Iuliia S; Luckham, Paul F

    2017-04-01

    Ionic liquids can serve as an environmentally-friendly replacement for solvents in emulsions, therefore they are considered suitable to be used as an emulsified medium for various active materials one of which are extractors of metal ions. Increasing the extraction efficiency is considered to be one of the key objectives when working with such extraction systems. One way to improve the extraction efficiency is to increase the contact area between the extractant and the working ionic solution. This can be accomplished by creating a nano-emulsion of ionic liquid containing such an extractant. Since emulsification of ionic liquid is not always possible in the sample itself, there is a necessity of creating a stable emulsion that can be added externally and on demand to samples from which metal ions need to be extracted. We propose a method of fabrication of a highly-stable extractant-loaded ionic liquid-in-water nano-emulsion via a low-energy phase reversal emulsification followed by continuous layer-by-layer polyelectrolyte deposition process to encapsulate the nano-emulsion and enhance the emulsion stability. Such a multilayered stabilized nano-emulsion was tested for extraction of Cd(2+) and Ca(2+) ions in order to determine its extraction efficiency and selectivity. It was found to be effective in the extraction of Cd(2+) ions with near 100% cadmium removal, as well as being selective since no Ca(2+) ions were extracted. The encapsulated emulsion was removed from samples post-extraction using two methods - filtration and magnetic separation, both of which were shown to be viable under different circumstances - larger and mechanically stronger capsules could be removed by filtration, however magnetic separation worked better for both smaller and bigger capsules. The long-term stability of nano-emulsion was also tested being a very important characteristic for its proposed use: it was found to be highly stable after four months of storage time.

  4. 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.

  5. Utilization of Mg2Al-layered double hydroxide as an effective sequestrator to trap Cu(II) ions from aqueous solution impacted by water quality parameters

    Science.gov (United States)

    Xu, Meng; Linghu, Wensheng; Hu, Jun; Jiang, Gongyi; Sheng, Jiang

    2016-11-01

    Recently, Mg2Al-layered double hydroxide (Mg2Al-LDH) has been extensively studied as promising candidates to trap metal ions due to their high complexation and adsorption capacity. Herein, Mg2Al-LDH was utilized as an effectiveness sequestrator to trap Cu(II) ions from aqueous solution by an adsorption process using batch technique under ambient conditions. The results showed that Cu(II) adsorption on Mg2Al-LDH increases with pH increasing and maintains a high level at pH>7.0. The adsorption of Cu(II) was obviously affected by ionic strength at low pH, which was not dependent on ionic strength at high pH. The presence of HA or FA promotes the adsorption of Cu(II) on Mg2Al-LDH at low pH values, while reduces the adsorption of Cu(II) at high pH values. The adsorption isotherms of Cu(II) on Mg2Al-LDH at three different temperatures were simulated by the Langmuir, Freundlich, and Dubinin-Radushkevitch (D-R) models very well. The thermodynamic parameters were determined from the temperature-dependent adsorption, and the results showed that Cu(II) adsorption on Mg2Al-LDH was exothermic and the process was favored at high temperature. The results suggest that Mg2Al-LDH is suitable as a sorbent material for the recovery and attenuation of Cu(II)-polluted wastewater.

  6. Beam Profile Measurement of 300 kV Ion Source Test Stand for 1 MV Electrostatic Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sae-Hoon; Kim, Yu-Seok [Dongguk University, Gyeonju (Korea, Republic of); Kim, Dae-Il; Kwon, Hyeok-Jung; Cho, Yong-Sub [Korea Multipurpose Accelerator Complex, Gyeongju (Korea, Republic of)

    2015-10-15

    In this paper, RF ion source, test stand of the ion source and its test results are presented. Beam profile was measured at the downstream from the accelerating tube and at the beam dump by using BPM and wire scanner. The RF ion source of the test stand is verified by measuring the total beam current with a faraday cup in the chamber. The KOMAC (KOrea Multi-purpose Accelerator Complex) has been developing a 300 kV ion source test stand for a 1 MV electrostatic accelerator. An ion source and accelerating tube will be installed in a high pressure vessel. The ion source in a high pressure vessel requires high reliability. To confirm the stable operation of the ion source, a test stand was proposed and developed. The ion source will be tested at the test stand to verify its long-term operation conditions. The test stand consists of a 300 kV high voltage terminal, a battery for the ion source power, a 60 Hz inverter, a 200 MHz RF power, a 5 kV extraction power supply, a 300 kV accelerating tube, and a vacuum system. The beam profile monitor was installed at the downstream from the accelerating tube. Wire scanner and faraday-cup was installed at the end of the chamber.

  7. Removal of cobalt ions from aqueous solutions by polymer assisted ultrafiltration using experimental design approach. part 1: optimization of complexation conditions.

    Science.gov (United States)

    Cojocaru, Corneliu; Zakrzewska-Trznadel, Grazyna; Jaworska, Agnieszka

    2009-09-30

    The polymer assisted ultrafiltration process combines the selectivity of the chelating agent with the filtration ability of the membrane acting in synergy. Such hybrid process (complexation-ultrafiltration) is influenced by several factors and therefore the application of experimental design for process optimization using a reduced number of experiments is of great importance. The present work deals with the investigation and optimization of cobalt ions removal from aqueous solutions by polymer enhanced ultrafiltration using experimental design and response surface methodological approach. Polyethyleneimine has been used as chelating agent for cobalt complexation and the ultrafiltration experiments were carried out in dead-end operating mode using a flat-sheet membrane made from regenerated cellulose. The aim of this part of experiments was to find optimal conditions for cobalt complexation, i.e. the influence of initial concentration of cobalt in feed solution, polymer/metal ratio and pH of feed solution, on the rejection efficiency and binding capacity of the polymer. In this respect, the central compositional design has been used for planning the experiments and for construction of second-order response surface models applicable for predictions. The analysis of variance has been employed for statistical validation of regression models. The optimum conditions for maximum rejection efficiency of 96.65% has been figured out experimentally by gradient method and was found to be as follows: [Co(2+)](0)=65 mg/L, polymer/metal ratio=5.88 and pH 6.84.

  8. Facile preparation of NiCo2O4@rGO composites for the removal of uranium ions from aqueous solutions.

    Science.gov (United States)

    Song, Xiumei; Tan, Lichao; Sun, Xiaojun; Ma, Huiyuan; Zhu, Lin; Yi, Xiaoqing; Dong, Qiang; Gao, Junyu

    2016-11-14

    A hierarchical structure of NiCo2O4@rGO composite has been fabricated, with its structure and morphology well characterized by XRD, TEM, XPS and BET. The results proved that the NiCo2O4 nanosheets grow uniformly on both sides of the graphene sheets. In batch adsorption experiments, the effects of equilibrium time, pH and temperature on uranium(vi) adsorption were investigated. The main results show that the NiCo2O4@rGO composite has a higher affinity towards the uptake of uranium(vi) from aqueous solutions. The highest adsorption capacity reached 342.4 mg U g(-1) at pH 5.0. Kinetic analysis shows that the adsorption process is described best by a pseudo-second-order kinetic model. The uranium(vi) sorption equilibrium data correlates well with the Langmuir sorption isotherm model in the thermodynamic analysis. Thus, NiCo2O4@rGO composite is an excellent adsorbent for removing uranium(vi) ions.

  9. Aspects on the catalysis of lipase from porcine pancreas (type VI-s in aqueous media: development of ion-pairs

    Directory of Open Access Journals (Sweden)

    Marina Kokkinou

    2012-04-01

    Full Text Available This article reports a first contribution for the elucidation of catalytic mechanism of Lipase from porcine pancreas, type VI-s (PPL, in hydrolyzing an ester substrate in aqueous media. The conclusions were based on the pH-profiles of Michaelis-Menten parameters k cat/Km, k cat and Km, as well as on the absolute temperature profile of k cat/Km, obtained during the hydrolysis of p-nitrophenyl laurate by PPL. It was found that (a PPL performs catalysis by means of ion pairs formed either as Ser152-Ο-/His263-Im+H and/or Carbonyl-Ο-/His263-Im+H, (b the parameter k cat/Km equals to k1 and thus ES is formed and destroyed in the course of a series of consecutive reactions governed by the dynamic constant K S = k2/k1, and (c the hydrolysis of substrate is assisted by a hydrogen bond developed between deprotonated Asp176 and the positively charged imidazole of His263 across a pKa-value 3.85, necessary for efficient catalysis.

  10. Evaluation of Acacia nilotica as a non conventional low cost biosorbent for the elimination of Pb(II and Cd(II ions from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Sadia Waseem

    2014-12-01

    Full Text Available In the present study a biomass derived from the leaves of Acacia nilotica was used as an adsorbent material for the removal of cadmium and lead from aqueous solution. The effect of various operating variables, viz., adsorbent dosage, contact time, pH and temperature on the removal of cadmium and lead has been studied. Maximum adsorption of cadmium and lead arises at a concentration of 2 g/50 ml and 3 g/50 ml and at a pH value of 5 and 4, respectively. The sorption data favored the pseudo-second-order kinetic model. Langmuir, Freundlich and Dubinin–Radushkevich (D–R models were applied to describe the biosorption isotherm of the metal ions by A. nilotica biomass. Based on regression coefficient, the equilibrium data found were fitted well to the Langmuir equilibrium model than other models. Thermodynamic parameters such as free energy change (ΔG°, enthalpy change (ΔH° and entropy change (ΔS° have been calculated, respectively revealed the spontaneous, endothermic and feasible nature of adsorption process. The activation energy of the biosorption (Ea was estimated as 9.34 kJ mol−1 for Pb and 3.47 kJ mol−1 for Cd from Arrhenius plot at different temperatures.

  11. Removal of Cd2+ and Cu2+ ions from aqueous solution by using Fe-Fe3O4/graphene oxide as a novel and efficient adsorbent

    Science.gov (United States)

    Le, Giang H.; Ha, Anh Q.; Nguyen, Quang K.; Nguyen, Kien T.; Dang, Phuong T.; Tran, Hoa T. K.; Vu, Loi D.; Nguyen, Tuyen V.; Lee, Gun D.; Vu, Tuan A.

    2016-10-01

    The nano Fe-Fe3O4/graphene oxide (GO) was successfully synthesized by the precipitation method and followed by chemical reduction using FeCl3 as iron sources and NaBH4 as reducing agent. The products were characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), BET, x-ray photoelectron spectroscopy (XPS) and VMS. From the obtained XRD and XPS results, it revealed the formation of both Fe and Fe3O4 nano particles on GO surface. TEM images showed that both Fe3O4/GO and Fe-Fe3O4/GO had small particle size of 10-20 nm and uniform size distribution. Fe3O4/GO and Fe-Fe3O4/GO were used as adsorbents for removal of Cd2+ and Cu2+ ions from aqueous solution. Maximum adsorption capacity (Q max) of Fe-Fe3O4/GO for Cu2+ and Cd2+ are 90.0 mg g-1 and 108.6 mg g-1, respectively. These values are much higher as compared to those of Fe3O4/GO as well as those reported in the literature. Additionally, this novel adsorbent can be reused by washing with diluted Hcl solution and easily recovered by applying the magnetic field. The Cd2+ adsorption isotherm fits better for the Langmuir model that of the Freundlich model and it obeys the pseudo-second order kinetic equation.

  12. Potentiometric studies on ternary complexes involving some divalent transition metal ions, gallic acid and biologically abundant aliphatic dicarboxylic acids in aqueous solutions

    Directory of Open Access Journals (Sweden)

    Abdelatty Mohamed Radalla

    2015-06-01

    Full Text Available Formation of binary and ternary complexes of the divalent transition metal ions, Cu2+, Ni2+, Co2+ and Zn2+ with gallic acid and the biologically important aliphatic dicarboxylic acids (adipic, succinic, malic, malonic, maleic, tartaric and oxalic acids were investigated by means of the potentiometric technique at 25 °C and I = 0.10 mol dm−3 NaNO3. The acid-base properties of the ligands were investigated and discussed. The acidity constants of gallic acid and aliphatic dicarboxylic acids were determined and used for determining the stability constants of the binary and ternary complexes formed in the aqueous medium under the above experimental conditions. The formation of the different 1:1 and 1:2 binary complexes and 1:1:1 ternary complexes are inferred from the corresponding potentiometric pH-metric titration curves. The ternary complex formation was found to occur in a stepwise manner. The stability constants of these binary and ternary systems were calculated. The values of Δ log K, percentage of relative stabilization (%R.S. and log X were evaluated and discussed. The concentration distribution of the various complex species formed in solution was evaluated and discussed. The mode of chelation of ternary complexes formed was ascertained by conductivity measurements.

  13. The front end test stand high performance H- ion source at Rutherford Appleton Laboratory.

    Science.gov (United States)

    Faircloth, D C; Lawrie, S; Letchford, A P; Gabor, C; Wise, P; Whitehead, M; Wood, T; Westall, M; Findlay, D; Perkins, M; Savage, P J; Lee, D A; Pozimski, J K

    2010-02-01

    The aim of the front end test stand (FETS) project is to demonstrate that chopped low energy beams of high quality can be produced. FETS consists of a 60 mA Penning Surface Plasma Ion Source, a three solenoid low energy beam transport, a 3 MeV radio frequency quadrupole, a chopper, and a comprehensive suite of diagnostics. This paper details the design and initial performance of the ion source and the laser profile measurement system. Beam current, profile, and emittance measurements are shown for different operating conditions.

  14. Numerical simulations of the first operational conditions of the negative ion test facility SPIDER

    Energy Technology Data Exchange (ETDEWEB)

    Serianni, G., E-mail: gianluigi.serianni@igi.cnr.it; Agostinetti, P.; Antoni, V.; Baltador, C.; Chitarin, G.; Marconato, N.; Pasqualotto, R.; Sartori, E.; Toigo, V.; Veltri, P. [Consorzio RFX (CNR, ENEA, INFN, UNIPD, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova (Italy); Cavenago, M. [INFN-LNL, Viale dell’Università n. 2, 35020 Legnaro (Italy)

    2016-02-15

    In view of the realization of the negative ion beam injectors for ITER, a test facility, named SPIDER, is under construction in Padova (Italy) to study and optimize production and extraction of negative ions. The present paper is devoted to the analysis of the expected first operations of SPIDER in terms of single-beamlet and multiple-beamlet simulations of the hydrogen beam optics in various operational conditions. The effectiveness of the methods adopted to compensate for the magnetic deflection of the particles is also assessed. Indications for a sequence of the experimental activities are obtained.

  15. Numerical simulations of the first operational conditions of the negative ion test facility SPIDER

    Science.gov (United States)

    Serianni, G.; Agostinetti, P.; Antoni, V.; Baltador, C.; Cavenago, M.; Chitarin, G.; Marconato, N.; Pasqualotto, R.; Sartori, E.; Toigo, V.; Veltri, P.

    2016-02-01

    In view of the realization of the negative ion beam injectors for ITER, a test facility, named SPIDER, is under construction in Padova (Italy) to study and optimize production and extraction of negative ions. The present paper is devoted to the analysis of the expected first operations of SPIDER in terms of single-beamlet and multiple-beamlet simulations of the hydrogen beam optics in various operational conditions. The effectiveness of the methods adopted to compensate for the magnetic deflection of the particles is also assessed. Indications for a sequence of the experimental activities are obtained.

  16. Antioxidant and Antifatigue Properties of the Aqueous Extract of Moringa oleifera in Rats Subjected to Forced Swimming Endurance Test

    Science.gov (United States)

    Lamou, Bonoy; Taiwe, Germain Sotoing; Hamadou, André; Abene; Houlray, Justin; Atour, Mahamat Mey; Tan, Paul Vernyuy

    2016-01-01

    The effects of the aqueous extract of Moringa oleifera on swimming performance and related biochemical parameters were investigated in male Wistar rats (130–132 g). Four groups of rats (16 per group) were fed a standard laboratory diet and given distilled water, 100, 200, or 400 mg/kg of extract, respectively, for 28 days. On day 28, 8 rats from each group were subjected to the forced swimming test with tail load (10% of body weight). The remaining 8 rats per group were subjected to the 90-minute free swim. Maximum swimming time, glycemia, lactamia, uremia, triglyceridemia, hepatic and muscle glycogen, hematological parameters, and oxidative stress parameters (superoxide dismutase, catalase, reduced glutathione, and malondialdehyde) were measured. Results. M. oleifera extract increased maximum swimming time, blood hemoglobin, blood glucose, and hepatic and muscle glycogen reserves. The extract also increased the activity of antioxidant enzymes and decreased the blood concentrations of malondialdehyde. Furthermore, it decreased blood concentrations of lactate, triglycerides, and urea. In conclusion, the antifatigue properties of M. oleifera extract are demonstrated by its ability to improve body energy stores and tissue antioxidant capacity and to reduce the tissue build-up of lactic acid. PMID:26904162

  17. Antioxidant and Antifatigue Properties of the Aqueous Extract of Moringa oleifera in Rats Subjected to Forced Swimming Endurance Test.

    Science.gov (United States)

    Lamou, Bonoy; Taiwe, Germain Sotoing; Hamadou, André; Abene; Houlray, Justin; Atour, Mahamat Mey; Tan, Paul Vernyuy

    2016-01-01

    The effects of the aqueous extract of Moringa oleifera on swimming performance and related biochemical parameters were investigated in male Wistar rats (130-132 g). Four groups of rats (16 per group) were fed a standard laboratory diet and given distilled water, 100, 200, or 400 mg/kg of extract, respectively, for 28 days. On day 28, 8 rats from each group were subjected to the forced swimming test with tail load (10% of body weight). The remaining 8 rats per group were subjected to the 90-minute free swim. Maximum swimming time, glycemia, lactamia, uremia, triglyceridemia, hepatic and muscle glycogen, hematological parameters, and oxidative stress parameters (superoxide dismutase, catalase, reduced glutathione, and malondialdehyde) were measured. Results. M. oleifera extract increased maximum swimming time, blood hemoglobin, blood glucose, and hepatic and muscle glycogen reserves. The extract also increased the activity of antioxidant enzymes and decreased the blood concentrations of malondialdehyde. Furthermore, it decreased blood concentrations of lactate, triglycerides, and urea. In conclusion, the antifatigue properties of M. oleifera extract are demonstrated by its ability to improve body energy stores and tissue antioxidant capacity and to reduce the tissue build-up of lactic acid.

  18. Project of electro-cyclotron resonance ion source test-bench for material investigation.

    Science.gov (United States)

    Kulevoy, T V; Chalykh, B B; Kuibeda, R P; Kropachev, G N; Ziiatdinova, A V

    2014-02-01

    Development of new materials for future energy facilities with higher operating efficiency is a challenging and crucial task. However, full-scale testing of radiation hardness for reactor materials is quite sophisticated and difficult as it requires long session of reactor irradiation; moreover, induced radioactivity considerably complicates further investigation. Ion beam irradiation does not have such a drawback; on the contrary, it has certain advantages. One of them is high speed of defect formation. Therefore, it provides a useful tool for modeling of different radiation damages. Improved understanding of material behavior under high dose irradiation will probably allow to simulate reactor irradiation close to real conditions and to make an adequate estimation of material radiation hardness. Since 2008 in Institute for Theoretical and Experimental Physics, the ion beam irradiation experiments are under development at the heavy ion radio frequency quadrupole linac and very important results are obtained already [T. V. Kulevoy et al., in Proceedings of the International Topical Meeting on Nuclear Research Applications and Utilization of Accelerators, IAEA Vienna, Austria, 2009, http://www.pub.iaea.org/MTCD/publications/PDF/P1433_CD/darasets/papers/ap_p5_07.pdf]. Nevertheless, the new test bench based on electro-cyclotron resonance ion source and high voltage platform is developed. The project of the test bench is presented and discussed.

  19. Potentiodynamic and galvanostatic testing of NaFe0.95V0.05PO4/C composite in aqueous NaNO3 solution, and the properties of aqueous Na1.2V3O8/NaNO3/NaFe0.95V0.05PO4/C battery

    Science.gov (United States)

    Vujković, Milica; Mentus, Slavko

    2016-09-01

    The NaFe0.95V0.05PO4/C composite is synthesized by electrochemical ion displacement from LiFe0.95V0.05PO4/C composite in aqueous NaNO3 solution. A coulombic capacity amounting to ∼105 and ∼82 mAh g-1 at sodiation/desodiation rate of 500 and 5000 mAg-1, respectively, is evidenced. For the sake of comparison the same investigations is performed with LiFe0.95V0.05PO4/C composite in LiNO3 solution, and better capacity retention and rate performance is evidenced for NaFe0.95V0.05PO4/C one. This advancement is found to be due a higher participation of pseudocapacity in the sodiation/desodiation charge storage process. An aqueous battery composed of NaFe0.95V0.05PO4/C cathode, belt-like Na1.2V3O8 anode and NaNO3 solution as an electrolyte, tested galvanostatically, displays long-life performance with only 10% of capacity fade after 1000 charge/discharge cycles.

  20. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS

    Energy Technology Data Exchange (ETDEWEB)

    Thomae, R., E-mail: rthomae@tlabs.ac.za; Conradie, J.; Fourie, D.; Mira, J.; Nemulodi, F. [iThemba LABS, P.O. Box 722, Somerset West 7130 (South Africa); Kuechler, D.; Toivanen, V. [CERN, BE/ABP/HSL, 1211 Geneva 23 (Switzerland)

    2016-02-15

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

  1. Construction and test of a high power injector of hydrogen cluster ions

    CERN Document Server

    Becker, E W; Hagena, O F; Henkes, P R W; Klingelhofer, R; Moser, H O; Obert, W; Poth, I

    1979-01-01

    A high power injector of hydrogen cluster ions, rated for 1 MV and 100 kW, is described. The injector is split in three separate tanks connected by a 1 MV transfer line. The cluster ion beam source and all its auxiliary equipment is placed at high voltage, insulated by SF/sub 6/ gas at pressure of 4 bar. The main components of the injector are: The cluster ion beam source with integrated helium cryopumps, the CERN type acceleration tube with 750 mm ID, the beam dump designed to handle the mass and energy flux under DC conditions, a 1 MV high voltage terminal for the auxiliary equipment supplied by its 40 kVA power supply with power, and the 1 MV 120 kW DC high voltage generator. This injector is installed in Karlsruhe. Performance tests were carried out successfully. It is intended to use this injector for refuelling experiments at the ASDEX Tokamak. (12 refs).

  2. Wave-particle resonance condition test for ion-kinetic waves in the solar wind

    Energy Technology Data Exchange (ETDEWEB)

    Narita, Y. [Austrian Academy of Sciences, Graz (Austria). Space Research Inst.; Technische Univ. Braunschweig (Germany). Inst. fuer Geophysik und extraterrestrische Physik; Marsch, E. [Kiel Univ. (Germany). Inst fuer Experimentelle und Angewandte Physik; Perschke, C. [Technische Univ. Braunschweig (Germany). Inst. fuer Geophysik und extraterrestrische Physik; Technische Univ. Braunschweig (Germany). Inst. fuer Theoretische Physik; Glassmeier, K.H. [Technische Univ. Braunschweig (Germany). Inst. fuer Geophysik und extraterrestrische Physik; Max-Planck-Institut fuer Sonnensystemforschung, Goettingen (Germany); Motschmann, U. [Technische Univ. Braunschweig (Germany). Inst. fuer Theoretische Physik; Deutsches Zentrum fuer Luft- und Raumfahrt, Berlin (Germany). Inst. fuer Planetenforschung; Comisel, H. [Technische Univ. Braunschweig (Germany). Inst. fuer Theoretische Physik; Institute for Space Sciences, Bucharest-Magurele (Romania)

    2016-08-01

    Conditions for the Landau and cyclotron resonances are tested for 543 waves (identified as local peaks in the energy spectra) in the magnetic field fluctuations of the solar wind measured by the Cluster spacecraft on a tetrahedral scale of 100 km. The resonance parameters are evaluated using the frequencies in the plasma rest frame, the parallel components of the wavevectors, the ion cyclotron frequency, and the ion thermal speed. The observed waves show a character of the sideband waves associated with the ion Bernstein mode, and are in a weak agreement with the fundamental electron cyclotron resonance in spite of the ionkinetic scales. The electron cyclotron resonance is likely taking place in solar wind turbulence near 1AU (astronomical unit).

  3. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS

    Science.gov (United States)

    Thomae, R.; Conradie, J.; Fourie, D.; Mira, J.; Nemulodi, F.; Kuechler, D.; Toivanen, V.

    2016-02-01

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

  4. Concepts for the magnetic design of the MITICA neutral beam test facility ion acceleratora)

    Science.gov (United States)

    Chitarin, G.; Agostinetti, P.; Marconato, N.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P.

    2012-02-01

    The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

  5. Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Chitarin, G. [Consorzio RFX, Corso Stati Uniti 4, 35127 Padova (Italy); Department of Engineering and Management, University of Padova, Vicenza (Italy); Agostinetti, P.; Marconato, N.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P. [Consorzio RFX, Corso Stati Uniti 4, 35127 Padova (Italy)

    2012-02-15

    The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

  6. Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator.

    Science.gov (United States)

    Chitarin, G; Agostinetti, P; Marconato, N; Marcuzzi, D; Sartori, E; Serianni, G; Sonato, P

    2012-02-01

    The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.

  7. Beam experiments with the Grenoble test electron cyclotron resonance ion source at iThemba LABS.

    Science.gov (United States)

    Thomae, R; Conradie, J; Fourie, D; Mira, J; Nemulodi, F; Kuechler, D; Toivanen, V

    2016-02-01

    At iThemba Laboratory for Accelerator Based Sciences (iThemba LABS) an electron cyclotron ion source was installed and commissioned. This source is a copy of the Grenoble Test Source (GTS) for the production of highly charged ions. The source is similar to the GTS-LHC at CERN and named GTS2. A collaboration between the Accelerators and Beam Physics Group of CERN and the Accelerator and Engineering Department of iThemba LABS was proposed in which the development of high intensity argon and xenon beams is envisaged. In this paper, we present beam experiments with the GTS2 at iThemba LABS, in which the results of continuous wave and afterglow operation of xenon ion beams with oxygen as supporting gases are presented.

  8. Reactive Geochemical Transport Modeling of Concentrated AqueousSolutions: Supplement to TOUGHREACT User's Guide for the PitzerIon-Interaction Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guoxiang; Spycher, Nicolas; Xu, Tianfu; Sonnenthal, Eric; Steefel , Carl

    2006-12-15

    In this report, we present: -- The Pitzer ion-interactiontheory and models -- Input file requirements for using the TOUGHREACTPitzer ion-interaction model and associated databases -- Run-time errormessages -- Verification test cases and application examples. For themain code structure, features, overall solution methods, description ofinput/output files for parameters other than those specific to theimplemented Pitzer model, and error messages, see the TOUGHREACT User'sGuide (Xu et al., 2005). The TOUGHREACT Pitzer version runs on aDEC-alpha architecture CPU, under OSF1 V5.1, with Compaq Digital FortranCompiler. The compiler run-time libraries are required for execution aswell as compilation. The code also runs on Intel Pentium IV andhigher-version CPU-based machines with Compaq Visual Fortran Compiler orIntel Fortran Compiler (integrated with the Microsoft DevelopmentEnvironment). The minimum hardware configuration should include 1 GB RAMand 1 GB (2 GB recommended) of available disk space.

  9. Design, synthesis, characterization and cation sensing behavior of amino-naphthoquinone receptor: Selective colorimetric sensing of Cu(II) ion in nearly aqueous solution with mimicking logic gate operation

    Science.gov (United States)

    Parthiban, C.; Elango, Kuppanagounder P.

    2017-03-01

    An amino-naphthoquione receptor (R1) has been rationally designed, synthesized and characterized using 1H and 13C NMR, LCMS and single crystal X-ray diffraction studies. The receptor exhibits an instantaneous colour change from yellow to blue selectively with Cu(II) ions in water-DMF (98:2% v/v) medium. The results of UV-Vis and fluorescence spectral studies indicates that the mechanism of sensing involves formation of a 1:1 complex between R1 and Cu(II) ion. The proposed mechanism has been confirmed through product analysis using FT-IR, UV-Vis, EPR and HRMS studies in addition to magnetic moment and elemental analysis measurements. The formed [Cu(R1)Cl2] possess a square planar geometry. The binding constant for the interaction of Cu(II) ion with the present unsubstituted quinone is found to be relatively higher than that with quinones containing electron withdrawing chlorine atom and electron releasing methyl group reported in literature. The detection limit of Cu(II) ion in aqueous solution by R1 is observed to be 8.7 nM. The detection of Cu(II) ion by R1 in aqueous solution produces remarkable changes in the electronic and fluorescence spectra, which is applied to construct logic gate at molecular level.

  10. Simulation and Optimization of Artificial Neural Network Modeling for Prediction of Sorption Efficiency of Nanocellulose Fibers for Removal of Cd (II Ions from Aqueous System

    Directory of Open Access Journals (Sweden)

    Abhishek KARDAM

    2014-06-01

    Full Text Available Simulation and optimization of an Artificial Neural Network (ANN for modeling biosorption studies of cadmium removal using nanocellulose fibers (NCFs was carried out. Experimental studies led to the standardization of the optimum conditions for the removal of cadmium ions i.e. biomass dosage (0.5 g, test volume (200 ml, metal concentration (25 mg/l, pH (6.5 and contact time (40 min. A Single layer ANN model was developed to simulate the process and to predict the sorption efficiency of Cd (II ions using NCFs. Different NN architectures were tested by varying network topology, resulting in excellent agreement between experiment outputs and ANN outputs. The findings indicated that ANN provided reasonable predictive performance for training, cross validation and testing data sets (R2 = 0.998, 0.995, 0.992. A sensitivity analysis was carried out to assess the influence of different independent parameters on the biosorption efficiency, and pH > biomass dosage > metal concentration > contact time > test volume were found to be the most significant factors. Simulations based on the developed ANN model can estimate the behavior of the biosorption phenomenon process under different experimental conditions.

  11. Manufacturing, assembly and tests of SPIDER Vacuum Vessel to develop and test a prototype of ITER neutral beam ion source

    Energy Technology Data Exchange (ETDEWEB)

    Zaccaria, Pierluigi, E-mail: pierluigi.zaccaria@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete S.p.A.), Padova (Italy); Valente, Matteo; Rigato, Wladi; Dal Bello, Samuele; Marcuzzi, Diego; Agostini, Fabio Degli; Rossetto, Federico; Tollin, Marco [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete S.p.A.), Padova (Italy); Masiello, Antonio [Fusion for Energy F4E, Barcelona (Spain); Corniani, Giorgio; Badalocchi, Matteo; Bettero, Riccardo; Rizzetto, Dario [Ettore Zanon S.p.A., Schio (VI) (Italy)

    2015-10-15

    Highlights: • The SPIDER experiment aims to qualify and optimize the ion source for ITER injectors. • The large SPIDER Vacuum Vessel was built and it is under testing at the supplier. • The main working and assembly steps for production are presented in the paper. - Abstract: The SPIDER experiment (Source for the Production of Ions of Deuterium Extracted from an RF plasma) aims to qualify and optimize the full size prototype of the negative ion source foreseen for MITICA (full size ITER injector prototype) and the ITER Heating and Current Drive Injectors. Both SPIDER and MITICA experiments are presently under construction at Consorzio RFX in Padova (I), with the financial support from IO (ITER Organization), Fusion for Energy, Italian research institutions and contributions from Japan and India Domestic Agencies. The vacuum vessel hosting the SPIDER in-vessel components (Beam Source and calorimeters) has been manufactured, assembled and tested during the last two years 2013–2014. The cylindrical vessel, about 6 m long and 4 m in diameter, is composed of two cylindrical modules and two torispherical lids at the ends. All the parts are made by AISI 304 L stainless steel. The possibility of opening/closing the vessel for monitoring, maintenance or modifications of internal components is guaranteed by bolted junctions and suitable movable support structures running on rails fixed to the building floor. A large number of ports, about one hundred, are present on the vessel walls for diagnostic and service purposes. The main working steps for construction and specific technological issues encountered and solved for production are presented in the paper. Assembly sequences and tests on site are furthermore described in detail, highlighting all the criteria and requirements for correct positioning and testing of performances.

  12. Microwave-assisted aqueous synthesis of transition metal ions doped ZnSe/ZnS core/shell quantum dots with tunable white-light emission

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jie [Laboratory of Advanced Materials, Fudan University, Shanghai 200438 (China); Chen, Qiuhang; Zhang, Wanlu; Mei, Shiliang; He, Liangjie; Zhu, Jiatao [Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Institute for Electric Light Sources, Fudan University, Shanghai 200433 (China); Chen, Guoping [School of Information Science and Technology, Fudan University, Shanghai 200433 (China); Guo, Ruiqian, E-mail: rqguo@fudan.edu.cn [Engineering Research Center of Advanced Lighting Technology, Ministry of Education, Institute for Electric Light Sources, Fudan University, Shanghai 200433 (China)

    2015-10-01

    Highlights: • ZnSe-based QDs were formed via a microwave-assisted aqueous approach. • The stabilizer, ZnS coats and UV irradiation played a role in the PL enhancement. • Tunable white-light-emitting Mn:ZnSe QDs and Cu,Mn:ZnSe/ZnS QDs were synthesized. • The formation mechanism of Cu,Mn:ZnSe QDs was clarified. • The corresponding CIE color coordinates of different PL spectra were obtained. - Abstract: Synthesis of bright white-light emitting Mn and Cu co-doped ZnSe/ZnS core/shell quantum dots (QDs) (Cu,Mn:ZnSe/ZnS) was reported. Water-soluble ZnSe-based QDs with Mn and Cu doping were prepared using a versatile hot-injection method in aqueous solution with a microwave-assisted approach. Influence of the Se/S ratio, stabilizer, refluxing time and the concentration of Cu/Mn dopant ions on the particle size and photoluminescence (PL) were investigated. The as-prepared QDs in the different stages of growth were characterized by X-ray powder diffractometer (XRD), high-resolution transmission electron microscopy (HRTEM), UV–visible (UV–vis) spectrophotometer, and fluorescence spectrophotometer. It is found that these ZnSe-based QDs synthesized under mild conditions exhibit emission in the range of 390–585 nm. The PL quantum yield (QY) of the as-prepared water-soluble ZnSe QDs can be up to 24.3% after the UV-irradiation treatment. The band-gap emission of ZnSe is effectively restrained through Mn and Cu doping. The refluxing time influences the doping of not only Mn, but also Cu, which leads to the best refluxing time of Mn:ZnSe and the red-shift of the emission of Cu:ZnSe d-dots. Co-doping induced white-light emission (WLE) from Cu,Mn:ZnSe/ZnS core/shell QDs were obtained, which can offer the opportunity for future-generation white-light emitting diodes (LEDs)

  13. First test of BNL electron beam ion source with high current density electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, Alexander, E-mail: pikin@bnl.gov; Alessi, James G., E-mail: pikin@bnl.gov; Beebe, Edward N., E-mail: pikin@bnl.gov [Brookhaven National Laboratory, Upton, NY 11973 (United States); Shornikov, Andrey; Mertzig, Robert; Wenander, Fredrik; Scrivens, Richard [CERN, CH-1211 Geneva 23 (Switzerland)

    2015-01-09

    A new electron gun with electrostatic compression has been installed at the Electron Beam Ion Source (EBIS) Test Stand at BNL. This is a collaborative effort by BNL and CERN teams with a common goal to study an EBIS with electron beam current up to 10 A, current density up to 10,000 A/cm{sup 2} and energy more than 50 keV. Intensive and pure beams of heavy highly charged ions with mass-to-charge ratio < 4.5 are requested by many heavy ion research facilities including NASA Space Radiation Laboratory (NSRL) at BNL and HIE-ISOLDE at CERN. With a multiampere electron gun, the EBIS should be capable of delivering highly charged ions for both RHIC facility applications at BNL and for ISOLDE experiments at CERN. Details of the electron gun simulations and design, and the Test EBIS electrostatic and magnetostatic structures with the new electron gun are presented. The experimental results of the electron beam transmission are given.

  14. First results of the ITER-relevant negative ion beam test facility ELISE (invited).

    Science.gov (United States)

    Fantz, U; Franzen, P; Heinemann, B; Wünderlich, D

    2014-02-01

    An important step in the European R&D roadmap towards the neutral beam heating systems of ITER is the new test facility ELISE (Extraction from a Large Ion Source Experiment) for large-scale extraction from a half-size ITER RF source. The test facility was constructed in the last years at Max-Planck-Institut für Plasmaphysik Garching and is now operational. ELISE is gaining early experience of the performance and operation of large RF-driven negative hydrogen ion sources with plasma illumination of a source area of 1 × 0.9 m(2) and an extraction area of 0.1 m(2) using 640 apertures. First results in volume operation, i.e., without caesium seeding, are presented.

  15. Towards a test of QED in investigations of the hyperfine splitting in heavy ions.

    Science.gov (United States)

    Shabaev, V M; Artemyev, A N; Yerokhin, V A; Zherebtsov, O M; Soff, G

    2001-04-30

    A possibility for investigations of quantum electrodynamics (QED) in experiments on the hyperfine splitting in heavy ions is examined. It is found that QED effects can be probed on the level of a few percent in a specific difference of the hyperfine splitting values in hydrogenlike and lithiumlike bismuth. This could provide a test of QED in the strongest electric field available at present for experimental study.

  16. Hydrogenlike highly charged ions for tests of the time independence of fundamental constants.

    Science.gov (United States)

    Schiller, S

    2007-05-04

    Hyperfine transitions in the electronic ground state of cold, trapped hydrogenlike highly charged ions have attractive features for use as frequency standards because the majority of systematic frequency shifts are smaller by orders of magnitude compared to many microwave and optical frequency standards. Frequency measurements of these transitions hold promise for significantly improved laboratory tests of local position invariance of the electron and quark masses.

  17. Kinetics and equilibrium studies on biosorption of cadmium, lead, and nickel ions from aqueous solutions by intact and chemically modified brown algae

    Energy Technology Data Exchange (ETDEWEB)

    Montazer-Rahmati, Mohammad Mehdi, E-mail: mrahmati@ut.ac.ir [School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box: 11155-4563, Tehran 4563 (Iran, Islamic Republic of); Rabbani, Parisa; Abdolali, Atefeh [School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box: 11155-4563, Tehran 4563 (Iran, Islamic Republic of); Keshtkar, Ali Reza [Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, P.O. Box: 11365-8486, Tehran (Iran, Islamic Republic of)

    2011-01-15

    Research highlights: {yields} The present study deals with the evaluation of biosorptive removal of Cd (II), Ni (II) and Pb (II) ions by both intact and pre-treated brown marine algae: Cystoseira indica, Sargassum glaucescens, Nizimuddinia zanardini and Padina australis treated with formaldehyde (FA), glutaraldehyde (GA), polyethylene imine (PEI), calcium chloride (CaCl{sub 2}) and hydrochloric acid (HCl). From the results obtained, chemically modification leads to higher capacity of biosorption. {yields} The equilibrium experimental data were tested using the most common isotherms. The results are best fitted by the Freundlich model among two-parameter models and the Toth, Khan and Radke-Prausnitz models among three-parameter isotherm models for Cd (II), Ni (II) and Pb (II), respectively. {yields} One-way ANOVA and one sample t-tests were performed on experimental data to evaluate the statistical significance of biosorption capacities after five cycles of sorption and desorption. {yields} The kinetic data were fitted by models including pseudo-first-order and pseudo-second-order. From the results obtained, the pseudo-second-order kinetic model describes best the biosorption of cadmium, nickel and lead ions. - Abstract: The present study deals with the evaluation of biosorptive removal of Cd (II), Ni (II) and Pb (II) ions by both intact and pre-treated brown marine algae: Cystoseira indica, Sargassum glaucescens, Nizimuddinia zanardini and Padina australis treated with formaldehyde (FA), glutaraldehyde (GA), polyethylene imine (PEI), calcium chloride (CaCl{sub 2}) and hydrochloric acid (HCl). Batch shaking adsorption experiments were performed in order to examine the effects of pH, contact time, biomass concentration, biomass treatment and initial metal concentration on the removal process. The optimum sorption conditions for each heavy metal are presented. One-way ANOVA and one sample t-tests were performed on experimental data to evaluate the statistical

  18. Polymer pendant ligand chemistry. 3. A biomimetic approach to selective metal ion removal and recovery from aqueous solution with polymer-supported sulfonated catechol and linear catechol amide ligands

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Song-Ping; Li, Wei; Franz, K.J.; Albright, R.L.; Fish, R.H. [Univ. of California, Berkeley, CA (United States)

    1995-05-24

    The design of organic ligands to selectively remove and recover metal ions from aqueous solution is a new and important area of environmental inorganic chemistry. One approach to designing organic ligands for these purposes is to use biological systems as examples for selective metal ion complexation. Thus, the authors report results on the synthesis of several biomimetically important polymer-supported, sulfonated catechol (PS-CATS), sulfonated bis(catechol) linear amide (PS-2-6-LICAMS), and sulfonated 3.3-linear tris(catechol) amide (PS-3,3-LICAMS) ligands that are chemically bonded to modified 6% cross-linked macroporous polystyrene-divinylbenzene beads (PS-DVB) for selective removal and recovery of environmentally and economically important metal ions from aqueous solution, as a function of pH. The Fe{sup 3+} ion selectivity was dramatically shown for PS-CATS, PS-2-6-LICAMS and PS-3,3-LICAMS polymer beads in competition with a similar concentration of Cu{sup 2+}, Zn{sup 2+}, Mn{sup 2+}, Ni{sup 2+}, Mg{sup 2+}, Al{sup 3+}, and Cr{sup 3+} ions at pH 1-3, while metal ion selectivity could be changed at higher pH values in the absence of Fe{sup 3+} (for example, Hg{sup 2+} at pH 3). Rates of removal and recovery of the Fe{sup 3+} ion with the PS-CATS, PS-2-6LICAMS and PS-3,3-LICAMS polymer beads were also studied as well as relative equilibrium selectivity coefficient (K{sub m}) values for all metal competition studies.

  19. 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.

  20. An overview of the new test stand for H{sup −} ion sources at FNAL

    Energy Technology Data Exchange (ETDEWEB)

    Sosa, A., E-mail: asosa@fnal.gov; Bollinger, D. S.; Duel, K.; Karns, P. R.; Pellico, W.; Tan, C. Y. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510-5011 (United States)

    2016-02-15

    A new test stand at Fermi National Accelerator Laboratory (FNAL) is being constructed to carry out experiments to develop and upgrade the present magnetron-type sources of H{sup −} ions of up to 80 mA at 35 keV in the context of the Proton Improvement Plan. The aim of this plan is to provide high-power proton beams for the experiments at FNAL. The technical details of the construction and layout of this test stand are presented, along with a prospective set of diagnostics to monitor the sources.

  1. Preparation of Mg1.1Mn6O12·4.5H2O with nanobelt structure and its application in aqueous magnesium-ion battery

    Science.gov (United States)

    Zhang, Hongyu; Ye, Ke; Huang, Xiaomei; Wang, Xin; Cheng, Kui; Xiao, Xue; Wang, Guiling; Cao, Dianxue

    2017-01-01

    Aqueous rechargeable magnesium-ion batteries with low cost of magnesium resources have a potential to meet growing requirements for electric energy storage resulted from the similar electrochemical properties to lithium. The Mg1.1Mn6O12·4.5H2O named as magnesium octahedral molecular sieves (Mg-OMS-1) owns nanobelt structures as a cathode material for aqueous magnesium-ion battery. The morphology and structure of Mg-OMS-1 are measured by X-ray diffraction, scanning and transmission electron microscopy. The mechanism of magnesium-ion insertion/deinsertion from this host material and the theory specific capacity of Mg-OMS-1 are determined by cyclic voltammetry, electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. Mg-OMS-1 displays an excellent battery behavior for Mg2+ insertion and deinsertion in the magnesium-salt aqueous electrolyte. The initial discharge capacity of Mg-OMS-1 electrode can reach 248.8 ± 0.5 mAh g-1 at 10 mA g-1 in the 0.2 mol dm-3 Mg(NO3)2 aqueous electrolyte. Even back to 10 mA g-1 after the rate performance, the discharge capacity can achieve 214.1 ± 0.5 mAh g-1. The specific capacity retention rate is 90.4% after cycling 200 times at 100 mA g-1 in the 0.5 mol dm-3 Mg(NO3)2 electrolyte with a columbic efficiency of 99.7 ± 0.1% in the 5 times experiments.

  2. Adsorption performances and mechanisms of the newly synthesized N,N'-di (carboxymethyl) dithiocarbamate chelating resin toward divalent heavy metal ions from aqueous media

    Energy Technology Data Exchange (ETDEWEB)

    Jing Xiaosheng [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Liu Fuqiang, E-mail: jogia@163.com [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China) and Engineering Technology Research Center of Organic Toxic Substance Control and Resource Reuse of Jiangsu Province, Nanjing 210046 (China); Yang Xin; Ling Panpan; Li Lanjuan [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Long Chao; Li Aimin [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Engineering Technology Research Center of Organic Toxic Substance Control and Resource Reuse of Jiangsu Province, Nanjing 210046 (China)

    2009-08-15

    N,N'-di (carboxymethyl) dithiocarbamate chelating resin (PSDC) was synthesized by anchoring the chelating agent of N,N'-di (carboxymethyl) dithiocarbamate to the chloromethylated PS-DVB (Cl-PS-DVB) matrix, as a new adsorbent for removing divalent heavy metal ions from waste-stream. The physicochemical structures of Cl-PS-DVB and PSDC were elaborately characterized using Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), and were further morphologically characterized using BET and BJH methods. The adsorption performances of PSDC towards heavy metals such as Cu(II), Pb(II) and Ni(II) were systematically investigated, based upon which the adsorption mechanisms were deeply exploited. For the above target, the classic batch adsorption experiments were conducted to explore the kinetics and isotherms of the removal processes with pH-value, initial concentration, temperature, and contact time as the controlling parameters. The kinetic and isotherm data could be well elucidated with Lagergren-second-order equation and Langmuir model respectively. The strong affinity of PSDC toward these target soft acids could be well demonstrated with the electrostatic attraction and chelating interaction caused by IDA moiety and sulphur which were namely soft bases on the concept of hard and soft acids and bases (HASB). Thermodynamic parameters, involving {Delta}H{sup o}, {Delta}S{sup o} and {Delta}G{sup o} were also calculated from graphical interpretation of the experimental data. The standard heats of adsorption ({Delta}H{sup o}) were found to be endothermic and the entropy change values ({Delta}S{sup o}) were calculated to be positive for the adsorption of Cu(II), Pb(II) and Ni(II) ions onto the tested adsorbents. Negative values of {Delta}G{sup o} indicated that adsorption processes for all tested metal ions onto PSDC were spontaneous.

  3. LHC Heavy-Ion Collimation Quench Test at 6.37Z TeV

    CERN Document Server

    Hermes, Pascal Dominik; Bruce, Roderik; Hofle, Wolfgang; Holzer, Eva Barbara; Kalliokoski, Matti; Kotzian, Gerd; Mereghetti, Alessio; Mirarchi, Daniele; Quaranta, Elena; Redaelli, Stefano; Valentino, Gianluca; Valuch, Daniel; Wollmann, Daniel; Zerlauth, Markus; CERN. Geneva. ATS Department

    2016-01-01

    This note summarizes the collimation quench test MD with 208Pb82+ beams at 6.37Z TeV in which a quench of a dipole magnet in the dispersion suppressor (DS) downstream of the betatron collimation region (IR7) was achieved. The aim of the test was to experimentally validate the quench limit in this region by means of inducing high losses at the LHC collimation system and quench the magnet with the collimation debris mainly lost at the IR7 DS. It was the first test with heavy-ions in which the transverse damper (ADT) could be used to induce these losses over extended periods of time (approximately 10-15s) while previous tests used tune resonance crossing methods in which the beam loss is less controllable and faster. The quench was achieved at a beam loss rate of 15 kW. The note summarizes the measurement strategy, technical realization, the test results and implications for future heavy-ion operation.

  4. Kinetics and equilibrium studies on biosorption of cadmium, lead, and nickel ions from aqueous solutions by intact and chemically modified brown algae.

    Science.gov (United States)

    Montazer-Rahmati, Mohammad Mehdi; Rabbani, Parisa; Abdolali, Atefeh; Keshtkar, Ali Reza

    2011-01-15

    The present study deals with the evaluation of biosorptive removal of Cd (II), Ni (II) and Pb (II) ions by both intact and pre-treated brown marine algae: Cystoseira indica, Sargassum glaucescens, Nizimuddinia zanardini and Padina australis treated with formaldehyde (FA), glutaraldehyde (GA), polyethylene imine (PEI), calcium chloride (CaCl(2)) and hydrochloric acid (HCl). Batch shaking adsorption experiments were performed in order to examine the effects of pH, contact time, biomass concentration, biomass treatment and initial metal concentration on the removal process. The optimum sorption conditions for each heavy metal are presented. One-way ANOVA and one sample t-tests were performed on experimental data to evaluate the statistical significance of biosorption capacities after five cycles of sorption and desorption. The equilibrium experimental data were tested using the most common isotherms. The results are best fitted by the Freundlich model among two-parameter models and the Toth, Khan and Radke-Prausnitz models among three-parameter isotherm models for Cd (II), Ni (II) and Pb (II), respectively. The kinetic data were fitted by models including pseudo-first-order and pseudo-second-order. From the results obtained, the pseudo-second-order kinetic model best describes the biosorption of cadmium, nickel and lead ions.

  5. Development and tests of molybdenum armored copper components for MITICA ion source

    Science.gov (United States)

    Pavei, Mauro; Böswirth, Bernd; Greuner, Henri; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo

    2016-02-01

    In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

  6. Development and tests of molybdenum armored copper components for MITICA ion source

    Energy Technology Data Exchange (ETDEWEB)

    Pavei, Mauro, E-mail: mauro.pavei@igi.cnr.it; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo [Consorzio RFX, Corso Stati Uniti, 4, I-35127 Padova (Italy); Böswirth, Bernd; Greuner, Henri [Max-Planck-Institut für Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2016-02-15

    In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

  7. First tests of the ion irradiation and implantation beamline at the CMAM

    Science.gov (United States)

    Jiménez-Rey, D.; Benedicto, M.; Muñoz-Martín, A.; Bachiller-Perea, D.; Olivares, J.; Climent-Font, A.; Gómez-Ferrer, B.; Rodríguez, A.; Narros, J.; Maira, A.; Álvarez, J.; Nakbi, A.; Zucchiatti, A.; de Aragón, F.; García, J. M.; Vila, R.

    2014-07-01

    The implantation and irradiation beamline of the Tandem ion accelerator of the Centro de Micro Análisis de Materiales (CMAM), in Madrid, has been recently completed with a beam sweep and monitoring system, and a cryostat/furnace. These new implementations convert the beamline into a versatile tool to implant ions, between H and Au2, in different materials with precise control of the sample temperature, which may be varied between -180 °C and 600 °C. The size of the swept area on target may be as large as 10 × 10 cm2. The implantation chamber also allows carrying out in situ or/and on line analyses during the irradiations by means of advanced optical measurements, as well as ion beam analyses (IBA). These advancements can be employed in novel applications such as the fabrication of optical waveguides and irradiation tests of structural and functional materials for future fusion reactors. The results of beam tests and first experiments are shown.

  8. First tests of the ion irradiation and implantation beamline at the CMAM

    Energy Technology Data Exchange (ETDEWEB)

    Jiménez-Rey, D. [Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Madrid 28049 (Spain); Laboratorio Nacional de Fusión, EURATOM/CIEMAT, CIEMAT, Avda. Complutense 40, Madrid 28040 (Spain); Benedicto, M.; Muñoz-Martín, A. [Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Madrid 28049 (Spain); Bachiller-Perea, D. [Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Madrid 28049 (Spain); Dpto. de Física Aplicada, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, Madrid 28049 (Spain); Olivares, J. [Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Madrid 28049 (Spain); Dpto. de Física Aplicada, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, Madrid 28049 (Spain); Laboratorio Nacional de Fusión, EURATOM/CIEMAT, CIEMAT, Avda. Complutense 40, Madrid 28040 (Spain); Instituto de Óptica, CSIC, Calle Serrano 121, Madrid 28006 (Spain); Climent-Font, A. [Centro de Micro-Análisis de Materiales, Universidad Autónoma de Madrid, C/Faraday 3, Madrid 28049 (Spain); Dpto. de Física Aplicada, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, Madrid 28049 (Spain); and others

    2014-07-15

    The implantation and irradiation beamline of the Tandem ion accelerator of the Centro de Micro Análisis de Materiales (CMAM), in Madrid, has been recently completed with a beam sweep and monitoring system, and a cryostat/furnace. These new implementations convert the beamline into a versatile tool to implant ions, between H and Au{sub 2}, in different materials with precise control of the sample temperature, which may be varied between −180 °C and 600 °C. The size of the swept area on target may be as large as 10 × 10 cm{sup 2}. The implantation chamber also allows carrying out in situ or/and on line analyses during the irradiations by means of advanced optical measurements, as well as ion beam analyses (IBA). These advancements can be employed in novel applications such as the fabrication of optical waveguides and irradiation tests of structural and functional materials for future fusion reactors. The results of beam tests and first experiments are shown.

  9. 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.

  10. A critical test for distorted wave theories: laser-assisted single ionization by ion impact

    Energy Technology Data Exchange (ETDEWEB)

    Ciappina, Marcelo [Max-Planck-Institut fuer Physik Komplexer Systeme, Dresden (Germany); Madsen, Lars Bojer [Department of Physics and Astronomy, Univ. of Aarhus (Denmark)

    2008-07-01

    We study single ionization in laser-assisted high-energy non-relativistic ion-atom collisions and show that the low-energy angular differential electron spectrum may be enhanced significantly by a weak external field. With increasing the strength of the assisting field, the energy spectrum develops a plateau with a characteristic cut-off. In the plateau region we predict distinct multiphoton peaks separated by the photon-energy of the laser field. In the present laser-assisted continuum-distorted-wave eikonal-initial-state (LA-CDW-EIS) theory, this effect may be related to the dynamics in the two-body electron-projectile subsystem. The combined process where an electron is ionized by a heavy ion and subsequently moves in the laser field and under the influence of the Coulomb fields of the projectile and the target represents a stringent test for distorted wave theories.

  11. Test of Time Dilation Using Stored Li+ Ions as Clocks at Relativistic Speed

    CERN Document Server

    Botermann, Benjamin; Geppert, Christopher; Gwinner, Gerald; Hänsch, Theodor W; Huber, Gerhard; Karpuk, Sergei; Krieger, Andreas; Kühl, Thomas; Nörtershäuser, Wilfried; Novotny, Christian; Reinhardt, Sascha; Sánchez, Rodolfo; Schwalm, Dirk; Stöhlker, Thomas; Wolf, Andreas; Saathoff, Guido

    2014-01-01

    We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ ions confined at a velocity of beta = v/c = 0.338 in the storage ring ESR at Darmstadt. A Lambda-type three-level system within the hyperfine structure of the 7Li+ triplet S1-P2 line is driven by two laser beams aligned parallel and antiparallel relative to the ion beam. The lasers' Doppler shifted frequencies required for resonance are measured with an accuracy of < 4 ppb using optical-optical double resonance spectroscopy. This allows us to verify the Special Relativity relation between the time dilation factor gamma and the velocity beta to within 2.3 ppb at this velocity. The result, which is singled out by a high boost velocity beta, is also interpreted within Lorentz Invariance violating test theories.

  12. Model for collisional fast ion diffusion into Tokamak Fusion Test Reactor loss cone

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.S. [New York Univ., NY (United States). Courant Inst. of Mathematical Sciences]|[Korea Advanced Inst. of Science and Technology, Seoul (Korea, Republic of); Zweben, S.J.; Schivell, J.; Budny, R.; Scott, S. [Princeton Univ., NJ (United States). Plasma Physics Lab.

    1994-08-01

    An analytic model is developed to estimate the classical pitch angle scattering loss of energetic fusion product ions into prompt loss orbits in a tokamak geometry. The re