WorldWideScience

Sample records for metal ions obtained

  1. Means for obtaining a metal ion beam from a heavy-ion cyclotron source

    Science.gov (United States)

    Hudson, E.D.; Mallory, M.L.

    1975-08-01

    A description is given of a modification to a cyclotron ion source used in producing a high intensity metal ion beam. A small amount of an inert support gas maintains the usual plasma arc, except that it is necessary for the support gas to have a heavy mass, e.g., xenon or krypton as opposed to neon. A plate, fabricated from the metal (or anything that can be sputtered) to be ionized, is mounted on the back wall of the ion source arc chamber and is bombarded by returning energetic low-charged gas ions that fail to cross the initial accelerating gap between the ion source and the accelerating electrode. Some of the atoms that are dislodged from the plate by the returning gas ions become ionized and are extracted as a useful beam of heavy ions. (auth)

  2. Composite materials obtained by the ion-plasma sputtering of metal compound coatings on polymer films

    Science.gov (United States)

    Khlebnikov, Nikolai; Polyakov, Evgenii; Borisov, Sergei; Barashev, Nikolai; Biramov, Emir; Maltceva, Anastasia; Vereshchagin, Artem; Khartov, Stas; Voronin, Anton

    2016-01-01

    In this article, the principle and examples composite materials obtained by deposition of metal compound coatings on polymer film substrates by the ion-plasma sputtering method are presented. A synergistic effect is to obtain the materials with structural properties of the polymer substrate and the surface properties of the metal deposited coatings. The technology of sputtering of TiN coatings of various thicknesses on polyethylene terephthalate films is discussed. The obtained composites are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and scanning tunneling microscopy (STM) is shown. The examples of application of this method, such as receiving nanocomposite track membranes and flexible transparent electrodes, are considered.

  3. Cellulose Nanocrystals Obtained from Rice By-Products and Their Binding Potential to Metallic Ions

    Directory of Open Access Journals (Sweden)

    Vanessa L. Albernaz

    2015-01-01

    Full Text Available The present study aimed to develop and optimize a method to obtain cellulose nanocrystals from the agricultural by-products rice husk and straw and to evaluate their electrostructural modifications in the presence of metallic ions. First, different particle formation conditions and routes were tested and analyzed by spectrophotometry, dynamic light scattering (DLS, and Zeta potential measurements. Then, electrostructural effects of ions Na(I, Cd(II, and Al(III on the optimized nanoparticles were analyzed by atomic force microscopy (AFM, scanning electron microscopy (SEM, and electrical conductivity (EC assessments. The produced cellulose nanocrystals adopted a rod-like shape. AFM height distribution and EC data indicated that the nanocrystals have more affinity in binding with Na(I > Al(III > Cd(II. These data suggest that the use of these cellulose nanocrystals in the bioremediation field is promising, both in metal sorption from wastewater and as an alternative for water desalination.

  4. Magnetic properties of thin films obtained by ion implantation of 3d metals in polyethylene-terephthalate

    International Nuclear Information System (INIS)

    Petukhov, V.Yu.; Ibragimova, M.I.; Khabibullina, N.R; Zheglov, E.P.; Muller, R.

    2002-01-01

    Polymer films containing small metal particles have been attracting particular interest because of their unique properties. Implantation of metal ions in polymers is one of the methods to synthesize metal-polymer nano-composite materials. Ion implantation makes possible the magnetic nano-structures with controlled parameters. Previously, we showed that 3d-metal implantation into numerous polymers (polymethylmethacrylate, phosphorus containing polymethylmethacrylate) resulted in the formation of a composite film consisting of metal nanoparticles buried in an implanted layer. The particles are usually found to be distributed randomly in the surface layer. It has been established that structural peculiarities, phase composition, and magnetic properties of synthesized metal-polymer systems depend on the type of the initial polymer matrix, ion types, as well as conditions of ion implantation. In the present study we have been prepared thin metal-polymer composite films by ion-beam implantation of Fe + and Co + ions in polyethylene terephthalate. The implantation of 40 keV ions at room temperature with doses from 2·10 1 6 to 3·10 17 cm -2 have been performed, with the ion current density not exceeding 10 μA/cm 2 . The magnetic properties have been investigated both by ferromagnetic resonance (FMR) and vibrating sample magnetometry (VSM). FMR spectra were recorded using magnetic radio spectrometer Varian E-12 with frequency of 9.5 GHz at room temperature. The dependencies of FMR spectra on orientation have been measured for all samples. Measurements were carried out for two orientations of the sample, normal direction of the films being either parallel or perpendicular to dc magnetic field. The values of the effective magnetization were calculated from orientation dependencies. Thin ferromagnetic films (TFF) have been shown to form for samples with both implanted ions. For samples implanted with Co + ions, the appearance of FMR lines occurs at doses markedly greater

  5. Metallic microwires obtained as replicas of etched ion tracks in polymer matrixes: Microscopy and emission properties

    International Nuclear Information System (INIS)

    Zagorski, D.L.; Bedin, S.A.; Oleinikov, V.A.; Polyakov, N.B.; Rybalko, O.G.; Mchedlishvili, B.V.

    2009-01-01

    Specially prepared porous matrixes (with through and dead-end pores of cylindrical or conical forms) were used as the templates for making ensembles of microwires. The process of electrodeposition of metal (Cu) into these pores was investigated. AFM technique was used for studying the 'composite material' (metal microwires embedded into the polymer matrix). It was shown that the combination of different modes of AFM (tapping with phase-contrast mode, contact with lateral force mode) makes it possible to detect metal in the polymer matrix. Additional spread resistance mode in the contact regime allowed to measure the electrical conductivity of a single wire. The ensembles of free-standing microwires (metallic replicas of the pores obtained after removing of the polymer matrix) were used as the substrates (for deposition of the probe) for ion emission in the mass-spectrometer. It was shown that the intensity of formed ion beam increases with increasing of power of the laser pulse and with increasing of the mass of the probe. The intensity of mass-spectra signal on the power of laser pulse has a threshold character with saturation accompanied with the appearance of dimer ions. At the same time this intensity decreases with the increasing of the surface density of wires. The effect of degradation of wires during the laser pulse irradiation was found.

  6. Obtaining sorbents of metal ions based on yeast cells Rhodotorula glutinis

    Directory of Open Access Journals (Sweden)

    Zh. Tattibayeva

    2013-05-01

    Full Text Available Ability to separate Cu2+ and Pb2+ ions from solution using yeast cells Rhodotorulа glutinis were considered. The degree of water purification in this case is of 60-70%. To increase the degree of binding of metal ions with cells and facilitate separation processes of water sorbents their immobilization on the surface of the water in the presence of polyethyleneimine was carried out. It is shown that under optimal conditions on the surface of 1 g diatomite 18 ∙ 106 cells is adsorbed. The high sorption capacity of diatomite justified its porosity. IR spectroscopic study of the interaction of the ions Cu2+ and Pb2+ with cell surface showed that high affinity Pb2 + ions to the surface of yeast cells is connected with form of slightly soluble compounds with the phosphate ions.

  7. Coprecipitation of alkali metal ions with calcium carbonate

    International Nuclear Information System (INIS)

    Okumura, Minoru; Kitano, Yasushi

    1986-01-01

    The coprecipitation of alkali metal ions Li + , Na + , K + and Rb + with calcium carbonate has been studied experimentally and the following results have been obtained: (1) Alkali metal ions are more easily coprecipitated with aragonite than with calcite. (2) The relationship between the amounts of alkali metal ions coprecipitated with aragonite and their ionic radii shows a parabolic curve with a peak located at Na + which has approximately the same ionic radius as Ca 2+ . (3) However, the amounts of alkali metal ions coprecipitated with calcite decrease with increasing ionic radius of alkali metals. (4) Our results support the hypothesis that (a) alkali metals are in interstitial positions in the crystal structure of calcite and do not substitute for Ca 2+ in the lattice, but (b) in aragonite, alkali metals substitute for Ca 2+ in the crystal structure. (5) Magnesium ions in the parent solution increase the amounts of alkali metal ions (Li + , Na + , K + and Rb + ) coprecipitated with calcite but decrease those with aragonite. (6) Sodium-bearing aragonite decreases the incorporation of other alkali metal ions (Li + , K + and Rb + ) into the aragonite. (author)

  8. A biosystem for removal of metal ions from water

    Energy Technology Data Exchange (ETDEWEB)

    Kilbane, J.J. II.

    1990-01-01

    The presence of heavy metal ions in ground and surface waters constitutes a potential health risk and is an environmental concern. Moreover, processes for the recovery of valuable metal ions are of interest. Bioaccumulation or biosorption is not only a factor in assessing the environmental risk posed by metal ions; it can also be used as a means of decontamination. A biological system for the removal and recovery of metal ions from contaminated water is reported here. Exopolysaccharide-producing microorganisms, including a methanotrophic culture, are demonstrated to have superior metal binding ability, compared with other microbial cultures. This paper describes a biosorption process in which dried biomass obtained from exopolysaccharide-producing microorganisms is encapsulated in porous plastic beads and is used for metal ion binding and recovery. 22 refs., 13 figs.

  9. Plasma immersion surface modification with metal ion plasma

    International Nuclear Information System (INIS)

    Brown, I.G.; Yu, K.M.; Godechot, X.

    1991-04-01

    We describe here a novel technique for surface modification in which metal plasma is employed and by which various blends of plasma deposition and ion implantation can be obtained. The new technique is a variation of the plasma immersion technique described by Conrad and co-workers. When a substrate is immersed in a metal plasma, the plasma that condenses on the substrate remains there as a film, and when the substrate is then implanted, qualitatively different processes can follow, including' conventional' high energy ion implantation, recoil implantation, ion beam mixing, ion beam assisted deposition, and metallic thin film and multilayer fabrication with or without species mixing. Multiple metal plasma guns can be used with different metal ion species, films can be bonded to the substrate through ion beam mixing at the interface, and multilayer structures can be tailored with graded or abrupt interfaces. We have fabricated several different kinds of modified surface layers in this way. 22 refs., 4 figs

  10. Recent Advances in Antimicrobial Hydrogels Containing Metal Ions and Metals/Metal Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Fazli Wahid

    2017-11-01

    Full Text Available Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional antimicrobial agents. Cross-linking of polymeric materials by metal ions or the combination of polymeric hydrogels with nanoparticles (metals and metal oxide is a simple and effective approach for obtaining a multicomponent system with diverse functionalities. Several metals and metal oxides such as silver (Ag, gold (Au, zinc oxide (ZnO, copper oxide (CuO, titanium dioxide (TiO2 and magnesium oxide (MgO have been loaded into hydrogels for antimicrobial applications. The incorporation of metals and metal oxide nanoparticles into hydrogels not only enhances the antimicrobial activity of hydrogels, but also improve their mechanical characteristics. Herein, we summarize recent advances in hydrogels containing metal ions, metals and metal oxide nanoparticles with potential antimicrobial properties.

  11. Use of heavy ions to model radiation damage of metals

    International Nuclear Information System (INIS)

    Shirokov, S.V.; Vyshemirskij, M.P.

    2011-01-01

    The methods for modeling radiation damage of metals using heavy ions are reviewed and the results obtained are analyzed. It is shown that irradiation of metals with heavy ion can simulate neutron exposure with the equivalent dose with adequate accuracy and permits a detailed analysis of radiation damage of metals

  12. The effects of metal ion PCR inhibitors on results obtained with the Quantifiler(®) Human DNA Quantification Kit.

    Science.gov (United States)

    Combs, Laura Gaydosh; Warren, Joseph E; Huynh, Vivian; Castaneda, Joanna; Golden, Teresa D; Roby, Rhonda K

    2015-11-01

    Forensic DNA samples may include the presence of PCR inhibitors, even after extraction and purification. Studies have demonstrated that metal ions, co-purified at specific concentrations, inhibit DNA amplifications. Metal ions are endogenous to sample types, such as bone, and can be introduced from environmental sources. In order to examine the effect of metal ions as PCR inhibitors during quantitative real-time PCR, 2800 M DNA was treated with 0.0025-18.750 mM concentrations of aluminum, calcium, copper, iron, nickel, and lead. DNA samples, both untreated and metal-treated, were quantified using the Quantifiler(®) Human DNA Quantification Kit. Quantification cycle (Cq) values for the Quantifiler(®) Human DNA and internal PCR control (IPC) assays were measured and the estimated concentrations of human DNA were obtained. Comparisons were conducted between metal-treated and control DNA samples to determine the accuracy of the quantification estimates and to test the efficacy of the IPC inhibition detection. This kit is most resistant to the presence of calcium as compared to all metals tested; the maximum concentration tested does not affect the amplification of the IPC or quantification of the sample. This kit is most sensitive to the presence of aluminum; concentrations greater than 0.0750 mM negatively affected the quantification, although the IPC assay accurately assessed the presence of PCR inhibition. The Quantifiler(®) Human DNA Quantification Kit accurately quantifies human DNA in the presence of 0.5000 mM copper, iron, nickel, and lead; however, the IPC does not indicate the presence of PCR inhibition at this concentration of these metals. Unexpectedly, estimates of DNA quantity in samples treated with 18.750 mM copper yielded values in excess of the actual concentration of DNA in the samples; fluorescence spectroscopy experiments indicated this increase was not a direct interaction between the copper metal and 6-FAM dye used to label the probe that

  13. Ion beam analysis of metal ion implanted surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Evans, P.J.; Chu, J.W.; Johnson, E.P.; Noorman, J.T. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia)

    1993-12-31

    Ion implantation is an established method for altering the surface properties of many materials. While a variety of analytical techniques are available for the characterisation of implanted surfaces, those based on particle accelerators such as Rutherford backscattering (RBS) and nuclear reaction analysis (NRA) provide some of the most useful and powerful for this purpose. Application of the latter techniques to metal ion implantation research at ANSTO will be described with particular reference to specific examples from recent studies. Where possible, the information obtained from ion beam analysis will be compared with that derived from other techniques such as Energy Dispersive X-ray (EDX) and Auger spectroscopies. 4 refs., 5 figs.

  14. Ion beam analysis of metal ion implanted surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Evans, P J; Chu, J W; Johnson, E P; Noorman, J T [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Sood, D K [Royal Melbourne Inst. of Tech., VIC (Australia)

    1994-12-31

    Ion implantation is an established method for altering the surface properties of many materials. While a variety of analytical techniques are available for the characterisation of implanted surfaces, those based on particle accelerators such as Rutherford backscattering (RBS) and nuclear reaction analysis (NRA) provide some of the most useful and powerful for this purpose. Application of the latter techniques to metal ion implantation research at ANSTO will be described with particular reference to specific examples from recent studies. Where possible, the information obtained from ion beam analysis will be compared with that derived from other techniques such as Energy Dispersive X-ray (EDX) and Auger spectroscopies. 4 refs., 5 figs.

  15. Ion beam analysis of metal ion implanted surfaces

    International Nuclear Information System (INIS)

    Evans, P.J.; Chu, J.W.; Johnson, E.P.; Noorman, J.T.; Sood, D.K.

    1993-01-01

    Ion implantation is an established method for altering the surface properties of many materials. While a variety of analytical techniques are available for the characterisation of implanted surfaces, those based on particle accelerators such as Rutherford backscattering (RBS) and nuclear reaction analysis (NRA) provide some of the most useful and powerful for this purpose. Application of the latter techniques to metal ion implantation research at ANSTO will be described with particular reference to specific examples from recent studies. Where possible, the information obtained from ion beam analysis will be compared with that derived from other techniques such as Energy Dispersive X-ray (EDX) and Auger spectroscopies. 4 refs., 5 figs

  16. Effective charge of energetic ions in metals

    International Nuclear Information System (INIS)

    Kitagawa, M.; Brandt, W.

    1983-01-01

    The effective charge of energetic ion, as derived from stopping power of metals, is calculated by use of a dielectronic-response function method. The electronic distribution in the ion is described through the variational principle in a statistical approximation. The dependences of effective charge on the ion velocity, atomic number and r/sub s/-value of metal are derived at the low-velocity region. The effective charge becomes larger than the real charge of ion due to the close collisions. We obtain the quasi-universal equation of the fractional effective electron number of ion as a function of the ratio between the ionic size and the minimum distance approach. The comparsion between theoretical and experimental results of the effective charge is performed for the cases of N ion into Au, C and Al. We also discuss the equipartition rule of partially ionized ion at the high-velocity region

  17. Metal ion transporters and homeostasis.

    OpenAIRE

    Nelson, N

    1999-01-01

    Transition metals are essential for many metabolic processes and their homeostasis is crucial for life. Aberrations in the cellular metal ion concentrations may lead to cell death and severe diseases. Metal ion transporters play a major role in maintaining the correct concentrations of the various metal ions in the different cellular compartments. Recent studies of yeast mutants revealed key elements in metal ion homeostasis, including novel transport systems. Several of the proteins discover...

  18. Evaluation of complexing agents and column temperature in ion chromatographic separation of alkali metals, alkaline earth metals and transition metals ion

    International Nuclear Information System (INIS)

    Kelkar, Anoop; Pandey, Ashish; Name, Anil B.; Das, D.K.; Behere, P.G.; Mohd Afzal

    2015-01-01

    The aim of ion chromatography method development is the resolution of all metal ions of interests. Resolution can be improved by changing the selectivity. Selectivity in chromatography can be altered by changes in mobile phase (eg eluent type, eluent strength) or through changes in stationary phase. Temperature has been used in altering the selectivity of particularly in reversed phase liquid chromatography and ion exchange chromatography. Present paper describe the retention behaviour of alkali metals, alkaline earth metals and transition metal ions on a silica based carboxylate function group containing analyte column. Alkali metals, alkaline earth metals and transition metal ions were detected by ion conductivity and UV-VIS detectors respectively

  19. Metal ion binding to iron oxides

    Science.gov (United States)

    Ponthieu, M.; Juillot, F.; Hiemstra, T.; van Riemsdijk, W. H.; Benedetti, M. F.

    2006-06-01

    The biogeochemistry of trace elements (TE) is largely dependent upon their interaction with heterogeneous ligands including metal oxides and hydrous oxides of iron. The modeling of TE interactions with iron oxides has been pursued using a variety of chemical models. The objective of this work is to show that it is possible to model the adsorption of protons and TE on a crystallized oxide (i.e., goethite) and on an amorphous oxide (HFO) in an identical way. Here, we use the CD-MUSIC approach in combination with valuable and reliable surface spectroscopy information about the nature of surface complexes of the TE. The other objective of this work is to obtain generic parameters to describe the binding of the following elements (Cd, Co, Cu, Ni, Pb, and Zn) onto both iron oxides for the CD-MUSIC approach. The results show that a consistent description of proton and metal ion binding is possible for goethite and HFO with the same set of model parameters. In general a good prediction of almost all the collected experimental data sets corresponding to metal ion binding to HFO is obtained. Moreover, dominant surface species are in agreement with the recently published surface complexes derived from X-ray absorption spectroscopy (XAS) data. Until more detailed information on the structure of the two iron oxides is available, the present option seems a reasonable approximation and can be used to describe complex geochemical systems. To improve our understanding and modeling of multi-component systems we need more data obtained at much lower metal ion to iron oxide ratios in order to be able to account eventually for sites that are not always characterized in spectroscopic studies.

  20. Ion implantation and amorphous metals

    International Nuclear Information System (INIS)

    Hohmuth, K.; Rauschenbach, B.

    1981-01-01

    This review deals with ion implantation of metals in the high concentration range for preparing amorphous layers (>= 10 at%, implantation doses > 10 16 ions/cm 2 ). Different models are described concerning formation of amorphous phases of metals by ion implantation and experimental results are given. The study of amorphous phases has been carried out by the aid of Rutherford backscattering combined with the channeling technique and using transmission electron microscopy. The structure of amorphous metals prepared by ion implantation has been discussed. It was concluded that amorphous metal-metalloid compounds can be described by a dense-random-packing structure with a great portion of metal atoms. Ion implantation has been compared with other techniques for preparing amorphous metals and the adventages have been outlined

  1. Ion implantation in metals

    International Nuclear Information System (INIS)

    Vook, F.L.

    1977-02-01

    The application of ion beams to metals is rapidly emerging as a promising area of research and technology. This report briefly describes some of the recent advances in the modification and study of the basic properties of metals by ion implantation techniques. Most of the research discussed illustrates some of the new and exciting applications of ion beams to metals which are under active investigation at Sandia Laboratories, Albuquerque

  2. Preparation of Dithizone Functionalized Polystyrene for Detecting Heavy Metal Ion

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Hyeon Ho; Kim, Younghun [Kwangwoon University, Seoul (Korea, Republic of)

    2015-04-15

    Colorimetric sensors were usually used to detect specific metal ions using selective color change of solutions. While almost organic dye in colorimetric sensors detected single molecule, dithizone (DTZ) solution could be separately detected above 5 kinds of heavy metal ions by the change of clear color. Namely, DTZ could be used as multicolorimetric sensors. However, DTZ was generally used as aqueous type and paper/pellet-type DTZ was not reported yet. Therefore, in this work, polystyrene (PS) was prepared to composite with DTZ and then DTZ/PS pellet was obtained, which was used to selectively detect 10 kinds of heavy metal ions. When 10 ppm of Hg and Co ions was exposed in DTZ/PS pellets, clear color change was revealed. It is noted that DTZ/PS pellet could be used in detecting of heavy metal ion as dry type.

  3. Isotherms of ion exchange on titanates of alkaline metals

    International Nuclear Information System (INIS)

    Fillina, L.P.; Belinskaya, F.A.

    1986-01-01

    Present article is devoted to isotherms of ion exchange on titanates of alkaline metals. Therefore, finely dispersed hydrated titanates of alkaline metals (lithium, sodium, potassium) with ion exchange properties are obtained by means of alkaline hydrolysis of titanium chloride at high ph rates. Sorption of cations from salts solution of Li 2 SO 4 , NaNO 3 , Ca(NO 3 ) 2 , AgNO 3 by titanates is studied.

  4. New Proton-Ionizable, Calixarene-Based Ligands for Selective Metal Ion Separations

    Energy Technology Data Exchange (ETDEWEB)

    Bartsch, Richard A.

    2012-06-04

    The project objective was the discovery of new ligands for performing metal ion separations. The research effort entailed the preparation of new metal ion complexing agents and polymers and their evaluation in metal ion separation processes of solvent extraction, synthetic liquid membrane transport, and sorption. Structural variations in acyclic, cyclic, and bicyclic organic ligands were used to probe their influence upon the efficiency and selectivity with which metal ion separations can be performed. A unifying feature of the ligand structures is the presence of one (or more) side arm with a pendent acidic function. When a metal ion is complexed within the central cavity of the ligand, ionization of the side arm(s) produces the requisite anion(s) for formation of an overall electroneutral complex. This markedly enhances extraction/transport efficiency for separations in which movement of aqueous phase anions of chloride, nitrate, or sulfate into an organic medium would be required. Through systematic structural variations, new ligands have been developed for efficient and selective separations of monovalent metal ions (e.g., alkali metal, silver, and thallium cations) and of divalent metal ion species (e.g., alkaline earth metal, lead, and mercury cations). Research results obtained in these fundamental investigations provide important insight for the design and development of ligands suitable for practical metal ion separation applications.

  5. Validation of ion chromatography for the determination of transition metal ions along with alkali, alkaline earth metal elements for uranium oxide fuel

    International Nuclear Information System (INIS)

    Kelkar, Anoop; Prakash, Amrit; Afzal, Mohd.; Panakkal, J.P.

    2009-02-01

    The present report describes the use of Ion chromatography (IC) methods with spectrophotometric and direct conductivity detection for the determination of transition metal elements and alkali alkaline earth metal ions in UO 2 pellets. Transmet analytical column and Metrosep- cation 1-2 column were used for the separation of transition metal elements and alkali and alkaline earth metal elements respectively. Oxalic acid and mixture of pyridine 2,6-dicarboxylic acid (PDCA), Na 2 SO 4 and NaCl were used as mobile phase for the separation of transition metal ions and monitored after post - column reaction with 4,2-pyridylazo resorcinol (PAR) at 520nm spectrophotometrically. In the determination of alkali and alkaline earth metal ions the interference of transition metals are removed by complexing them with PDCA. Mixture of tartaric acid and PDCA employed in the separation of alkali and alkaline earth metal ions and monitored on direct conductivity detector. Mobile phase composition was optimised for the base line separation. Calibration plots of Fe 3+ , Cu 2+ , Ni 2+ , Co 2+ , Cd 2+ , Mn 2+ , Li + , Na + , K + , Mg 2+ , Ca 2+ and Sr 2+ were linear over a wide dynamic range with regression coefficient better than 0.999. Detection limit of above ions were between 5-30ppb. To prevent the overloading of the cation exchange column, uranium matrix was removed from UO 2 sample by solvent extraction with 30% TBP - TOPO/CCl 4 . Ten sintered UO2 pellets of same lot were analysed and R.S.D. ±10% was obtained. These methods were validated by analysis of ILCE standards of UO 2 . (author)

  6. Metal Ion Controlled Polymorphism of a Peptide

    DEFF Research Database (Denmark)

    Hemmingsen, Lars Bo Stegeager; Jancso, Attila; Szunyogh, Daniel

    2011-01-01

    ions on fully or partially unstructured proteins, or the effect of metal ions on protein aggregation. Metal ions may be employed to fold (or misfold) individual peptides in a controlled manner depending on the potential metal ion coordinating amino acid side chains (Cys, His, Asp, Glu......In this work a metal ion binding model dodecapeptide was investigated in terms of its capacity to adopt different structures depending on the metal ion to peptide stoichiometry. The dodecapeptide is much simpler than real proteins, yet displays sufficient complexity to model the effect of metal......, …) in the peptide, and the ligand and structural preferences of the metal ion (in our studies Zn2+, Cd2+, Hg2+, Cu+/2+). Simultaneously, new species such as metal ion bridged ternary complexes or even oligomers may be formed. In recent previous studies we have observed similar polymorphism of zinc finger model...

  7. Polyatomic ions from a high current ion implanter driven by a liquid metal ion source

    Science.gov (United States)

    Pilz, W.; Laufer, P.; Tajmar, M.; Böttger, R.; Bischoff, L.

    2017-12-01

    High current liquid metal ion sources are well known and found their first application as field emission electric propulsion thrusters in space technology. The aim of this work is the adaption of such kind of sources in broad ion beam technology. Surface patterning based on self-organized nano-structures on, e.g., semiconductor materials formed by heavy mono- or polyatomic ion irradiation from liquid metal (alloy) ion sources (LMAISs) is a very promising technique. LMAISs are nearly the only type of sources delivering polyatomic ions from about half of the periodic table elements. To overcome the lack of only very small treated areas by applying a focused ion beam equipped with such sources, the technology taken from space propulsion systems was transferred into a large single-end ion implanter. The main component is an ion beam injector based on high current LMAISs combined with suited ion optics allocating ion currents in the μA range in a nearly parallel beam of a few mm in diameter. Different types of LMAIS (needle, porous emitter, and capillary) are presented and characterized. The ion beam injector design is specified as well as the implementation of this module into a 200 kV high current ion implanter operating at the HZDR Ion Beam Center. Finally, the obtained results of large area surface modification of Ge using polyatomic Bi2+ ions at room temperature from a GaBi capillary LMAIS will be presented and discussed.

  8. Metal ion implantation: Conventional versus immersion

    International Nuclear Information System (INIS)

    Brown, I.G.; Anders, A.; Anders, S.; Dickinson, M.R.; MacGill, R.A.

    1994-01-01

    Vacuum-arc-produced metal plasma can be used as the ion feedstock material in an ion source for doing conventional metal ion implantation, or as the immersing plasma for doing plasma immersion ion implantation. The basic plasma production method is the same in both cases; it is simple and efficient and can be used with a wide range of metals. Vacuum arc ion sources of different kinds have been developed by the authors and others and their suitability as a metal ion implantation tool has been well established. Metal plasma immersion surface processing is an emerging tool whose characteristics and applications are the subject of present research. There are a number of differences between the two techniques, both in the procedures used and in the modified surfaces created. For example, the condensibility of metal plasma results in thin film formation and subsequent energetic implantation is thus done through the deposited layer; in the usual scenario, this recoil implantation and the intermixing it produces is a feature of metal plasma immersion but not of conventional energetic ion implantation. Metal plasma immersion is more suited (but not limited) to higher doses (>10 17 cm -2 ) and lower energies (E i < tens of keV) than the usual ranges of conventional metal ion implantation. These and other differences provide these vacuum-arc-based surface modification tools with a versatility that enhances the overall technological attractiveness of both

  9. Reactions of metal ions and their clusters in the gas phase using laser ionization: ion cyclotron resonance spectroscopy

    International Nuclear Information System (INIS)

    Freiser, B.S.

    1981-04-01

    Two subjects are discussed in this report: advances in proposed studies on metal ion chemistry and expansion of laboratory facilities. The development of a combined pulsed laser source-ion cyclotron resonance spectrometer has proven to be a convenient and powerful method for generating metal ions and for studying their subsequent chemistry in the gas phase. The main emphasis of this research has been on the application of metal ions as a selective chemical ionization reagents and progress in this area are discussed. The goal is to identify trends in reactivity i.e. mechanisms useful in interpreting the chemical ionization spectra of unknown compounds and to test for the functional group selectivity of the various metal ions. The feasibility of these goals have been demonstrated in extensive studies on Cu + with esters and ketones, on Fe + with ethers, ketones, and hydrocarbons, and on Ti + with hydrocarbons. In addition, preliminary results on sulfur containing compounds and on a variety of other metallic ions have been obtained. Laboratory facilities were expanded from one ion cyclotron resonance (ICR) spectrometer to two, plus a third instrument the Fourier Transform Ion Cyclotron Resonance (FTICR) spectrometer

  10. A high current metal vapour vacuum arc ion source for ion implantation studies

    International Nuclear Information System (INIS)

    Evans, P.J.; Noorman, J.T.; Watt, G.C.; Cohen, D.D.; Bailey, G.M.

    1989-01-01

    The main features of the metal vapour vacuum arc(MEVA) as an ion source are presented. The technology utilizes the plasma production capabilities of a vacuum arc cathode. Some of the ions produced in this discharge flow through the anode and the 3 extraction grids to form an extracted ion beam. The high beam current and the potential for generating broad beams, make this technology suitable for implantation of large surface areas. The composition of the vacuum arc cathode determines the particular ions obtained from the MEVA source. 3 refs., 1 tab., 2 figs

  11. Potentiometric titration of metal ions in ethanol.

    Science.gov (United States)

    Gibson, Graham T T; Mohamed, Mark F; Neverov, Alexei A; Brown, R S

    2006-09-18

    The potentiometric titrations of Zn2+, Cu2+ and 12 Ln3+ metal ions were obtained in ethanol to determine the titration constants (defined as the at which the [-OEt]/[Mx+]t ratios are 0.5, 1.5, and 2.5) and in two cases (La3+ and Zn2+) a complete speciation diagram. Several simple monobasic acids and aminium ions were also titrated to test the validity of experimental titration measurements and to establish new constants in this medium that will be useful for the preparation of buffers and standard solutions. The dependence of the titration constants on the concentration and type of metal ion and specific counterion effects is discussed. In selected cases, the titration profiles were analyzed using a commercially available fitting program to obtain information about the species present in solution, including La3+ for which a dimer model is proposed. The fitting provides the microscopic values for deprotonation of one to four metal-bound ethanol molecules. Kinetics for the La3+-catalyzed ethanolysis of paraoxon as a function of are presented and analyzed in terms of La3+ speciation as determined by the analysis of potentiometric titration curves. The stability constants for the formation of Zn2+ and Cu2+ complexes with 1,5,9-triazacyclododecane as determined by potentiometric titration are presented.

  12. New developments in metal ion implantation by vacuum arc ion sources and metal plasma immersion

    International Nuclear Information System (INIS)

    Brown, I.G.; Anders, A.; Anders, S.

    1996-01-01

    Ion implantation by intense beams of metal ions can be accomplished using the dense metal plasma formed in a vacuum arc discharge embodied either in a vacuum arc ion source or in a metal plasma immersion configuration. In the former case high energy metal ion beams are formed and implantation is done in a more-or-less conventional way, and in the latter case the substrate is immersed in the plasma and repetitively pulse-biased so as to accelerate the ions at the high voltage plasma sheath formed at the substrate. A number of advances have been made in the last few years, both in plasma technology and in the surface modification procedures, that enhance the effectiveness and versatility of the methods, including for example: controlled increase of the in charge states produced; operation in a dual metal-gaseous ion species mode; very large area beam formation; macroparticle filtering; and the development of processing regimes for optimizing adhesion, morphology and structure. These complementary ion processing techniques provide the plasma tools for doing ion surface modification over a very wide parameter regime, from pure ion implantation at energies approaching the MeV level, through ion mixing at energies in the ∼1 to ∼100 keV range, to IBAD-like processing at energies from a few tens of eV to a few keV. Here the authors review the methods, describe a number of recent developments, and outline some of the surface modification applications to which the methods have been put. 54 refs., 9 figs

  13. Studies on indigenous ion exchange resins: alkali metal ions-hydrogen ion exchange equilibria

    International Nuclear Information System (INIS)

    Shankar, S.; Kumar, Surender; Venkataramani, B.

    2001-01-01

    With a view to select a suitable ion exchange resin for the removal of radionuclides (such as cesium, strontium etc.) from low level radioactive effluents, alkali metal ion -H' exchanges on nine indigenous gel- and macroporous-type and nuclear grade resins have been studied at a total ionic strength of 0.1 mol dm .3 (in the case ofCs' -H' exchange it was 0.05 mol dm .3 ). The expected theoretical capacities were not attained by all the resins for the alkali metal ions. The water content (moles/equiv.) of the fully swollen resins for different alkali metal ionic forms do not follow the usual sequence of greater the tendency of the cation to hydrate the higher the water uptake, but a reverse trend. The ion exchange isotherms (plots of equivalent fractions of the ion in resin phase, N M1 to that in solution, N M ) were not satisfactory and sorption of cations, for most of the resins, was possible only when the acidity of the solution was lowered. The variations of the selectivity coefficient, K, with N M show that the resins are highly cross linked and the selectivity sequence: Cs + >K + >Na + >Li + , obtained for all the resins indicate that hydrated ions were involved in the exchange process. However, the increase in the selectivity was not accompanied by the release of water, but unusual uptake of water, during the exchange process. The characteristics of macroporous resins were not significantly different from those of the gel-type resins. The results are discussed in terms of heterogeneity in the polymer net work, improper sulphonation process resulting in the formation of functional groups at inaccessible sites with weak acidic character and the overall lack of control in the preparation of different resins. (author)

  14. Synthesis and characterization of metal ion-imprinted polymers

    Indian Academy of Sciences (India)

    2018-03-29

    Mar 29, 2018 ... polymers (CPs) were synthesized through the same method without using metal ion. Characterization of the ... tizanidine obtained from MMIP-NPs showed that signifi- .... C=C vari- able alkene stretching band at 1636 cm. −1.

  15. Ion implantation of metals

    International Nuclear Information System (INIS)

    Dearnaley, G.

    1976-01-01

    In this part of the paper descriptions are given of the effects of ion implantation on (a) friction and wear in metals; and (b) corrosion of metals. In the study of corrosion, ion implantation can be used either to introduce a constituent that is known to convey corrosion resistance, or more generally to examine the parameters which control corrosion. (U.K.)

  16. Development of an Electrochemical Metal-Ion Biosensor Using Self-Assembled Peptide Nanofibrils

    DEFF Research Database (Denmark)

    Viguier, Bruno; Zor, Kinga; Kasotakis, Emmanouil

    2011-01-01

    . These nanofibrils were obtained under aqueous conditions, at room temperature and outside the clean room. The functionalized gold electrode was evaluated by cyclic voltammetry, impedance spectroscopy, energy dispersive X-ray and atomic force microscopy. The obtained results displayed a layer of nanofibrils able......This article describes the combination of self-assembled peptide nanofibrils with metal electrodes for the development of an electrochemical metal-ion biosensor. The biological nanofibrils were immobilized on gold electrodes and used as biorecognition elements for the complexation with copper ions...

  17. Modification of solid surface by intense pulsed light-ion and metal-ion beams

    Science.gov (United States)

    Nakagawa, Y.; Ariyoshi, T.; Hanjo, H.; Tsutsumi, S.; Fujii, Y.; Itami, M.; Okamoto, A.; Ogawa, S.; Hamada, T.; Fukumaru, F.

    1989-03-01

    Metal surfaces of Al, stainless-steel and Ti were bombarded with focused intense pulsed proton and carbon ion beams (energy ˜ 80 keV, current density ≲ 1000 A/cm 2, pulse width ˜ 300 ns). Thin titanium carbide layers were produced by carbon-ion irradiation on the titanium surface. The observed molten surface structures and recrystallized layer (20 μm depth) indicated that the surfaces reached high temperatures as a result of the irradiation. The implantation of intense pulsed metal ion beams (Al +, ˜ 20 A/cm 2) with simultaneous deposition of anode metal vapor on Ti and Fe made a mixed layer of AlTi and AlFe of about 0.5 μm depth. Ti and B multilayered films evaporated on glass substrates were irradiated by intense pulsed proton beams of relatively lower current density (10-200 A/cm 2). Ti films containing B atoms above 10 at.% were obtained. When the current density was about 200 A/cm 2 diffraction peaks of TiB 2 appeared.

  18. Pure high dose metal ion implantation using the plasma immersion technique

    International Nuclear Information System (INIS)

    Zhang, T.; Tang, B.Y.; Zeng, Z.M.; Kwok, T.K.; Chu, P.K.; Monteiro, O.R.; Brown, I.G.

    1999-01-01

    High energy implantation of metal ions can be carried out using conventional ion implantation with a mass-selected ion beam in scanned-spot mode by employing a broad-beam approach such as with a vacuum arc ion source, or by utilizing plasma immersion ion implantation with a metal plasma. For many high dose applications, the use of plasma immersion techniques offers a high-rate process, but the formation of a surface film along with the subsurface implanted layer is sometimes a severe or even fatal detriment. We describe here an operating mode of the metal plasma immersion approach by which pure implantation can be obtained. We have demonstrated the technique by carrying out Ti and Ta implantations at energies of about 80 and 120 keV for Ti and Ta, respectively, and doses on the order of 1x10 17 ions/cm 2 . Our experiments show that virtually pure implantation without simultaneous surface deposition can be accomplished. Using proper synchronization of the metal arc and sample voltage pulse, the applied dose that deposits as a film versus the part that is energetically implanted (the deposition-to-implantation ratio) can be precisely controlled.copyright 1999 American Institute of Physics

  19. Engineering of microorganisms towards recovery of rare metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, Kouichi; Ueda, Mitsuyoshi [Kyoto Univ. (Japan). Div. of Applied Life Sciences

    2010-06-15

    The bioadsorption of metal ions using microorganisms is an attractive technology for the recovery of rare metal ions as well as removal of toxic heavy metal ions from aqueous solution. In initial attempts, microorganisms with the ability to accumulate metal ions were isolated from nature and intracellular accumulation was enhanced by the overproduction of metal-binding proteins in the cytoplasm. As an alternative, the cell surface design of microorganisms by cell surface engineering is an emerging strategy for bioadsorption and recovery of metal ions. Cell surface engineering was firstly applied to the construction of a bioadsorbent to adsorb heavy metal ions for bioremediation. Cell surface adsorption of metal ions is rapid and reversible. Therefore, adsorbed metal ions can be easily recovered without cell breakage, and the bioadsorbent can be reused or regenerated. These advantages are suitable for the recovery of rare metal ions. Actually, the cell surface display of a molybdate-binding protein on yeast led to the enhanced adsorption of molybdate, one of the rare metal ions. An additional advantage is that the cell surface display system allows high-throughput screening of protein/peptide libraries owing to the direct evaluation of the displayed protein/peptide without purification and concentration. Therefore, the creation of novel metal-binding protein/ peptide and engineering of microorganisms towards the recovery of rare metal ions could be simultaneously achieved. (orig.)

  20. Versatile high current metal ion implantation facility

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

    1992-01-01

    A metal ion implantation facility has been developed with which high current beams of practically all the solid metals of the periodic table can be produced. A multicathode, broad-beam, metal vapor vacuum arc ion source is used to produce repetitively pulsed metal ion beams at an extraction voltage of up to 100 kV, corresponding to an ion energy of up to several hundred kiloelectronvolts because of the ion charge state multiplicity, and with a beam current of up to several amps peak pulsed and several tens of milliamps time averaged delivered onto a downstream target. Implantation is done in a broad-beam mode, with a direct line of sight from ion source to target. Here we summarize some of the features of the ion source and the implantation facility that has been built up around it. (orig)

  1. Real-time detection of metal ions using conjugated polymer composite papers.

    Science.gov (United States)

    Lee, Ji Eun; Shim, Hyeon Woo; Kwon, Oh Seok; Huh, Yang-Il; Yoon, Hyeonseok

    2014-09-21

    Cellulose, a natural polymeric material, has widespread technical applications because of its inherent structural rigidity and high surface area. As a conjugated polymer, polypyrrole shows practical potential for a diverse and promising range of future technologies. Here, we demonstrate a strategy for the real-time detection and removal of metal ions with polypyrrole/cellulose (PPCL) composite papers in solution. Simply, the conjugated polymer papers had different chemical/physical properties by applying different potentials to them, which resulted in differentiable response patterns and adsorption efficiencies for individual metal ions. First, large-area PPCL papers with a diameter of 5 cm were readily obtained via vapor deposition polymerization. The papers exhibited both mechanical flexibility and robustness, in which polypyrrole retained its redox property perfectly. The ability of the PPCL papers to recognize metal ions was examined in static and flow cells, in which real-time current change was monitored at five different applied potentials (+1, +0.5, 0, -0.5, and -1 V vs. Ag/AgCl). Distinguishable signals in the PPCL paper responses were observed for individual metal ions through principal component analysis. Particularly, the PPCL papers yielded unique signatures for three metal ions, Hg(ii), Ag(i), and Cr(iii), even in a real sample, groundwater. The sorption of metal ions by PPCL papers was examined in the flow system. The PPCL papers had a greatly superior adsorption efficiency for Hg(ii) compared to that of the other metal ions. With the strong demand for the development of inexpensive, flexible, light-weight, and environmentally friendly devices, the fascinating characteristics of these PPCL papers are likely to provide good opportunities for low-cost paper-based flexible or wearable devices.

  2. Spectrophotometric study of some metal ions using some Schiff's bases

    International Nuclear Information System (INIS)

    Elnager, Nawal Mohomed Ibrahim

    2000-05-01

    In this work two schiff bases namely N,N Bis(benzoyl acetone)-o-phenylene diamine (NNBBPD) and N,N Bis(benzoyl acetone)-isopropylene diamine (NNBBAID) were prepared by direct coupling of benzoyl acetone with o-phenylene and isopropylene diamine respectively. The two reagents were identified by IR spectra, thin layer chromatography (TLC) and determination of the percentage of nitrogen contents (N%). It is found that the two reagents form coloured chelates with Fe (II), Fe (III), Cu (II), U (VI), Ni (II) and Co (II). The two reagents were used for the determination of Fe (II), Fe (III) and U (VI). The formulate of these metal ion complexes were obtained using continuous variations, mole ratio and slope ratio methods. Effect of two micelles, namely sodium n-dodecyl sulphate (SDS) and hexadecyl pyridinum broinide monohydrate (HPB) on metal ion complexes were studied. It is found that both of them increase the solubility and the absorbances of the metal ion complexes with variable effects of the absorption maxima. Calibration curves for Fe (II), Fe (II) and U (VI) were obtained in optimum conditions of pH and micelles solutions. (Author)

  3. Portable Multispectral Colorimeter for Metallic Ion Detection and Classification.

    Science.gov (United States)

    Braga, Mauro S; Jaimes, Ruth F V V; Borysow, Walter; Gomes, Osmar F; Salcedo, Walter J

    2017-07-28

    This work deals with a portable device system applied to detect and classify different metallic ions as proposed and developed, aiming its application for hydrological monitoring systems such as rivers, lakes and groundwater. Considering the system features, a portable colorimetric system was developed by using a multispectral optoelectronic sensor. All the technology of quantification and classification of metallic ions using optoelectronic multispectral sensors was fully integrated in the embedded hardware FPGA ( Field Programmable Gate Array) technology and software based on virtual instrumentation (NI LabView ® ). The system draws on an indicative colorimeter by using the chromogen reagent of 1-(2-pyridylazo)-2-naphthol (PAN). The results obtained with the signal processing and pattern analysis using the method of the linear discriminant analysis, allows excellent results during detection and classification of Pb(II), Cd(II), Zn(II), Cu(II), Fe(III) and Ni(II) ions, with almost the same level of performance as for those obtained from the Ultravioled and visible (UV-VIS) spectrophotometers of high spectral resolution.

  4. Portable Multispectral Colorimeter for Metallic Ion Detection and Classification

    Directory of Open Access Journals (Sweden)

    Mauro S. Braga

    2017-07-01

    Full Text Available This work deals with a portable device system applied to detect and classify different metallic ions as proposed and developed, aiming its application for hydrological monitoring systems such as rivers, lakes and groundwater. Considering the system features, a portable colorimetric system was developed by using a multispectral optoelectronic sensor. All the technology of quantification and classification of metallic ions using optoelectronic multispectral sensors was fully integrated in the embedded hardware FPGA ( Field Programmable Gate Array technology and software based on virtual instrumentation (NI LabView®. The system draws on an indicative colorimeter by using the chromogen reagent of 1-(2-pyridylazo-2-naphthol (PAN. The results obtained with the signal processing and pattern analysis using the method of the linear discriminant analysis, allows excellent results during detection and classification of Pb(II, Cd(II, Zn(II, Cu(II, Fe(III and Ni(II ions, with almost the same level of performance as for those obtained from the Ultravioled and visible (UV-VIS spectrophotometers of high spectral resolution.

  5. Molten salt oxidation of ion-exchange resins doped with toxic metals and radioactive metal surrogates

    International Nuclear Information System (INIS)

    Yang, Hee-Chul; Cho, Yong-Jun; Yoo, Jae-Hyung; Kim, Joon-Hyung; Eun, Hee-Chul

    2005-01-01

    Ion-exchange resins doped with toxic metals and radioactive metal surrogates were test-burned in a bench-scale molten salt oxidation (MSO) reactor system. The purposes of this study are to confirm the destruction performance of the two-stage MSO reactor system for the organic ion-exchange resin and to obtain an understanding of the behavior of the fixed toxic metals and the sulfur in the cationic exchange resins. The destruction of the organics is very efficient in the primary reactor. The primarily destroyed products such as carbon monoxide are completely oxidized in the secondary MSO reactor. The overall collection of the sulfur and metals in the two-stage MSO reactor system appeared to be very efficient. Over 99.5% of all the fixed toxic metals (lead and cadmium) and radioactive metal surrogates (cesium, cobalt, strontium) remained in the MSO reactor bottom. Thermodynamic equilibrium calculations and the XRD patterns of the spent salt samples revealed that the collected metals existed in the form of each of their carbonates or oxides, which are non-volatile species at the MSO system operating conditions. (author)

  6. Metal vapor vacuum arc ion sources

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

    1990-06-01

    We have developed a family of metal vapor vacuum are (MEVVA) high current metal ion sources. The sources were initially developed for the production of high current beams of metal ions for heavy ion synchrotron injection for basic nuclear physics research; more recently they have also been used for metal ion implantation. A number of different embodiments of the source have been developed for these specific applications. Presently the sources operate in a pulsed mode, with pulse width of order 1 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, and since the ions produced in the vacuum arc plasma are in general multiply ionized the ion energy is up to several hundred keV. Beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Nearly all of the solid metals of the Periodic Table have been use to produce beam. A number of novel features have been incorporated into the sources, including multiple cathodes and the ability to switch between up to 18 separate cathode materials simply and quickly, and a broad beam source version as well as miniature versions. here we review the source designs and their performance. 45 refs., 7 figs

  7. Metallization of ion beam synthesized Si/3C-SiC/Si layer systems by high-dose implantation of transition metal ions

    International Nuclear Information System (INIS)

    Lindner, J.K.N.; Wenzel, S.; Stritzker, B.

    2001-01-01

    The formation of metal silicide layers contacting an ion beam synthesized buried 3C-SiC layer in silicon by means of high-dose titanium and molybdenum implantations is reported. Two different strategies to form such contact layers are explored. The titanium implantation aims to convert the Si top layer of an epitaxial Si/SiC/Si layer sequence into TiSi 2 , while Mo implantations were performed directly into the SiC layer after selectively etching off all capping layers. Textured and high-temperature stable C54-TiSi 2 layers with small additions of more metal-rich silicides are obtained in the case of the Ti implantations. Mo implantations result in the formation of the high-temperature phase β-MoSi 2 , which also grows textured on the substrate. The formation of cavities in the silicon substrate at the lower SiC/Si interface due to the Si consumption by the growing silicide phase is observed in both cases. It probably constitutes a problem, occurring whenever thin SiC films on silicon have to be contacted by silicide forming metals independent of the deposition technique used. It is shown that this problem can be solved with ion beam synthesized contact layers by proper adjustment of the metal ion dose

  8. Novel metal ion surface modification technique

    International Nuclear Information System (INIS)

    Brown, I.G.; Godechot, X.; Yu, K.M.

    1990-10-01

    We describe a method for applying metal ions to the near-surface region of solid materials. The added species can be energetically implanted below the surface or built up as a surface film with an atomically mixed interface with the substrate; the metal ion species can be the same as the substrate species or different from it, and more than one kind of metal species can be applied, either simultaneously or sequentially. Surface structures can be fabricated, including coatings and thin films of single metals, tailored alloys, or metallic multilayers, and they can be implanted or added onto the surface and ion beam mixed. We report two simple demonstrations of the method: implantation of yttrium into a silicon substrate at a mean energy of 70 keV and a dose of 1 x 10 16 atoms/cm 2 , and the formation of a titanium-yttrium multilayer structure with ion beam mixing to the substrate. 17 refs., 3 figs

  9. Metallic vapor supplying by the electron bombardment for a metallic ion production with an ECR ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kitagawa, Atsushi; Sasaki, Makoto; Muramatsu, Masayuki [National Inst. of Radiological Sciences, Chiba (Japan); Jincho, Kaoru; Sasaki, Noriyuki; Sakuma, Tetsuya; Takasugi, Wataru; Yamamoto, Mitsugu [Accelerator Engineering Corporation, Chiba (Japan)

    2001-11-19

    To produce the metallic ion beam for the injection into the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), a new gas supply method has been developed for an 18 GHz ECR ion source (NIRS-HEC). A metallic target rod at a high positive potential is melted by the electron bombardment technique. The evaporated gas with a maximum flow rate of 50A/sec is supplied into the ECR plasma in case of Fe metal. (author)

  10. Metallic vapor supplying by the electron bombardment for a metallic ion production with an ECR ion source

    International Nuclear Information System (INIS)

    Kitagawa, Atsushi; Sasaki, Makoto; Muramatsu, Masayuki; Jincho, Kaoru; Sasaki, Noriyuki; Sakuma, Tetsuya; Takasugi, Wataru; Yamamoto, Mitsugu

    2001-01-01

    To produce the metallic ion beam for the injection into the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS), a new gas supply method has been developed for an 18 GHz ECR ion source (NIRS-HEC). A metallic target rod at a high positive potential is melted by the electron bombardment technique. The evaporated gas with a maximum flow rate of 50A/sec is supplied into the ECR plasma in case of Fe metal. (author)

  11. Ion-beam-mixing in metal-metal systems and metal-silicon systems

    International Nuclear Information System (INIS)

    Hung, L.

    1984-01-01

    The influence of energetic ion bombardment on the composition and structure of thin film materials and utilization of ion-beam-mixing techniques to modify interfacial reactions are reported in this thesis. The phase formation in metals by using ion mixing techniques has been studied. Upon ion irradiation of Al/Pt, Al/Pd and Al/Ni thin films, only the simplest intermetallic compounds of PdAl and NiAl were formed in crystalline structure, while the amorphous phase has been observed over a large range of composition. Ion mixing of Au/Cu bilayers resulted in the formation of substitutional solid solutions with no trace of ordered compounds. The formation of the ordered compound CuAu was achieved either by irradiation of bilayers with Ar ions at elevated substrate temperature or by irradiation of the mixed layers with He ions at relatively low temperature. In the Au/Al system several crystal compounds existed in the as-deposited samples. These phases remained crystalline or transformed into other equilibrium compounds upon ion irradiation. The results suggest that the phase formation by ion mixing is dependent on the high quench rate in the collision cascade region and the atomic mobility at the irradiation temperature. The argument can be applied to silicide forming systems. With near-noble metals, the mixed atoms are mobile and form metallurgically distinct phases. With refractory metals, amorphous phases are formed due to lack of atomic mobility

  12. High charge state metal ion production in vacuum arc ion sources

    International Nuclear Information System (INIS)

    Brown, I.G.; Anders, A.; Anders, S.

    1994-01-01

    The vacuum arc is a rich source of highly ionized metal plasma that can be used to make a high current metal ion source. Vacuum arc ion sources have been developed for a range of applications including ion implantation for materials surface modification, particle accelerator injection for fundamental nuclear physics research, and other fundamental and applied purposes. Typically the source is repetitively pulsed with pulse length of order a millisecond and duty cycle or order 1% and operation of a dc embodiment has been demonstrated also. Beams have been produced from over 50 of the solid metals of the periodic table, with mean ion energy up to several hundred keV and with peak (pulsed) beam current up to several amperes. The ion charge state distribution has been extensively studied. Ion spectra have been measured for a wide range of metallic cathode materials, including Li, C, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sr, Y, Zr, Nb, Mo, Pd, Ag, Cd, In, Sn, Sb, Ba, La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Yb, Hf, Ta, W, Ir, Pt, Au, Pb, Bi, Th and U, as well as compound and alloy cathode materials such as TiC, SiC, UC, PbS, brass, and stainless steel. The ions generated are in general multiply-stripped with a mean charge state of from 1 to 3, depending on the particular metal species, and the charge state distribution can have components from Q = 1+ to 6+. Here the authors review the characteristics of vacuum arc ion sources from the perspective of their high charge state metal ion production

  13. Adsorption of heavy metal ions on different clays

    International Nuclear Information System (INIS)

    Kruse, K.

    1992-01-01

    The aim of the present dissertation is to study the adsorption of heavy metal ions (Cd 2+ , Cu 2+ , Pb 2+ , Zn 2+ ) and their mixtures on clays. Different clays and bentonites (Ca 2+ -bentonite, activated Na + -bentonite, special heavy metal adsorber bentonite, two organophilic bentonites and a mixed layer clay) were used. The adsorbed metal ions were desorbed by appropriate solutions of HCl, EDTA and dioctadecyl dimethylammonium bromide. High concentrations of the heavy metal ions in the solutions can be reached. The desorption guarantees economical recycling. After desorption the clays were used (up to three times) for purification of contaminated water. The best experimental conditions, i.e. the highest adsorption of heavy metal ions from aqueous solutions was found for the greatest ratio of adsorbent/adsorbate. The adsorption was very fast. Calcium, sodium bentonites and the heavy metal adsorber bentonite attained the highest adsorption and desorption for Cu 2+, Zn 2+ and Pb 2+ ions. Cd 2+ ions were only absorbed by Silitonit, a special heavy metal absorber bentonite. The mixed layer clay (Opalit) ranges in adsorption and desorption properties below the unmodified Ca 2+ -bentonite (Montigel) or the activated Na + -bentonite. Only Tixosorb and Tixogel (organophilic bentonites) reach the lowest value of heavy metal adsorption. Only lead cations which are characterised by good polarizability were adsorbed at higher rates, therefore the organophilic bentonites are not appropriate for adsorption of heavy metal ions from aqueous solutions. Mixing of the metal ions generally decreases the adsorption of Pb 2+ and increases the adsorption of Cd 2+ . From mixtures if heavy metal ions adsorption and desorption of Cu 2+ ions reached a maximum for all clays. (author) figs., tabs., 56 refs

  14. Metals in proteins: correlation between the metal-ion type, coordination number and the amino-acid residues involved in the coordination.

    Science.gov (United States)

    Dokmanić, Ivan; Sikić, Mile; Tomić, Sanja

    2008-03-01

    Metal ions are constituents of many metalloproteins, in which they have either catalytic (metalloenzymes) or structural functions. In this work, the characteristics of various metals were studied (Cu, Zn, Mg, Mn, Fe, Co, Ni, Cd and Ca in proteins with known crystal structure) as well as the specificity of their environments. The analysis was performed on two data sets: the set of protein structures in the Protein Data Bank (PDB) determined with resolution metal ion and its electron donors and the latter was used to assess the preferred coordination numbers and common combinations of amino-acid residues in the neighbourhood of each metal. Although the metal ions considered predominantly had a valence of two, their preferred coordination number and the type of amino-acid residues that participate in the coordination differed significantly from one metal ion to the next. This study concentrates on finding the specificities of a metal-ion environment, namely the distribution of coordination numbers and the amino-acid residue types that frequently take part in coordination. Furthermore, the correlation between the coordination number and the occurrence of certain amino-acid residues (quartets and triplets) in a metal-ion coordination sphere was analysed. The results obtained are of particular value for the identification and modelling of metal-binding sites in protein structures derived by homology modelling. Knowledge of the geometry and characteristics of the metal-binding sites in metalloproteins of known function can help to more closely determine the biological activity of proteins of unknown function and to aid in design of proteins with specific affinity for certain metals.

  15. Polymer Catalysts Imprinted with Metal Ions as Biomimics of Metalloenzymes

    Directory of Open Access Journals (Sweden)

    Joanna Czulak

    2013-01-01

    Full Text Available This work presents the preparation and properties of molecularly imprinted polymers (MIPs with catalytic centers that mimic the active sites of metalloenzymes. The MIP synthesis was based on suspension polymerization of functional monomers (4-vinylpyridine and acrylonitrile with trimethylolpropane trimethacrylate as a crosslinker in the presence of transition metal ions and 4-methoxybenzyl alcohol as a template. Four metal ions have been chosen for imprinting from among the microelements that are the most essential in the native enzymes: Cu2+, Co2+, Mn2+, and Zn2+. To prepare catalysts, the required loading of metal ions was obtained during sorption process. The catalysts imprinted with Cu2+, Co2+, and Zn2+ were successfully used for hydroquinone oxidation in the presence of hydrogen peroxide. The Mn2+-imprinted catalyst showed no activity due to the insufficient metal loading. Cu2+ MIP showed the highest efficiency. In case of Cu- and Co-MIP catalysts, their activity was additionally increased by the use of surface imprinting technique.

  16. Laccase Immobilization by Chelated Metal Ion Coordination Chemistry

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-09-01

    Full Text Available In this work, amidoxime polyacrylonitrile (AOPAN nanofibrous membrane was prepared by a reaction between PAN nanofibers and hydroxylamine hydrochloride. The AOPAN nanofibrous membranes were used for four metal ions (Fe3+, Cu2+, Ni2+, Cd2+ chelation under different conditions. Further, the competition of different metal ions coordinating with AOPAN nanofibrous membrane was also studied. The AOPAN chelated with individual metal ion (Fe3+, Cu2+, Ni2+, Cd2+ and also the four mixed metal ions were further used for laccase (Lac immobilization. Compared with free laccase, the immobilized laccase showed better resistance to pH and temperature changes as well as improved storage stability. Among the four individual metal ion chelated membranes, the stability of the immobilized enzymes generally followed the order as Fe–AOPAN–Lac > Cu–AOPAN–Lac > Ni–AOPAN–Lac > Cd–AOPAN–Lac. In addition, the immobilized enzyme on the carrier of AOPAN chelated with four mixed metal ions showed the best properties.

  17. Neutralization by metal ions of the toxicity of sodium selenide.

    Directory of Open Access Journals (Sweden)

    Marc Dauplais

    Full Text Available Inert metal-selenide colloids are found in animals. They are believed to afford cross-protection against the toxicities of both metals and selenocompounds. Here, the toxicities of metal salt and sodium selenide mixtures were systematically studied using the death rate of Saccharomyces cerevisiae cells as an indicator. In parallel, the abilities of these mixtures to produce colloids were assessed. Studied metal cations could be classified in three groups: (i metal ions that protect cells against selenium toxicity and form insoluble colloids with selenide (Ag⁺, Cd²⁺, Cu²⁺, Hg²⁺, Pb²⁺ and Zn²⁺, (ii metal ions which protect cells by producing insoluble metal-selenide complexes and by catalyzing hydrogen selenide oxidation in the presence of dioxygen (Co²⁺ and Ni²⁺ and, finally, (iii metal ions which do not afford protection and do not interact (Ca²⁺, Mg²⁺, Mn²⁺ or weakly interact (Fe²⁺ with selenide under the assayed conditions. When occurring, the insoluble complexes formed from divalent metal ions and selenide contained equimolar amounts of metal and selenium atoms. With the monovalent silver ion, the complex contained two silver atoms per selenium atom. Next, because selenides are compounds prone to oxidation, the stabilities of the above colloids were evaluated under oxidizing conditions. 5,5'-dithiobis-(2-nitrobenzoic acid (DTNB, the reduction of which can be optically followed, was used to promote selenide oxidation. Complexes with cadmium, copper, lead, mercury or silver resisted dissolution by DTNB treatment over several hours. With nickel and cobalt, partial oxidation by DTNB occurred. On the other hand, when starting from ZnSe or FeSe complexes, full decompositions were obtained within a few tens of minutes. The above properties possibly explain why ZnSe and FeSe nanoparticles were not detected in animals exposed to selenocompounds.

  18. Sorption of Heavy Metal Ions from Mine Wastewater by Activated ...

    African Journals Online (AJOL)

    Michael

    2016-12-02

    Dec 2, 2016 ... assess their heavy metal ions adsorption potential. The results show that the .... De-ionised water obtained from the Mineral. Engineering Laboratory of ... Batch adsorption experiment for each of the derived activated carbons ...

  19. Metallic ion release from biocompatible cobalt-based alloy

    Directory of Open Access Journals (Sweden)

    Dimić Ivana D.

    2014-01-01

    Full Text Available Metallic biomaterials, which are mainly used for the damaged hard tissue replacements, are materials with high strength, excellent toughness and good wear resistance. The disadvantages of metals as implant materials are their susceptibility to corrosion, the elastic modulus mismatch between metals and human hard tissues, relatively high density and metallic ion release which can cause serious health problems. The aim of this study was to examine metallic ion release from Co-Cr-Mo alloy in artificial saliva. In that purpose, alloy samples were immersed into artificial saliva with different pH values (4.0, 5.5 and 7.5. After a certain immersion period (1, 3 and 6 weeks the concentrations of released ions were determined using Inductively Coupled Plasma - Mass Spectrophotometer (ICP-MS. The research findings were used in order to define the dependence between the concentration of released metallic ions, artificial saliva pH values and immersion time. The determined released metallic ions concentrations were compared with literature data in order to describe and better understand the phenomenon of metallic ion release from the biocompatible cobalt-based alloy. [Projekat Ministarstva nauke Republike Srbije, br. III 46010 i br. ON 174004

  20. Metallic ions in the upper atmosphere

    International Nuclear Information System (INIS)

    Kumar, S.

    1979-01-01

    During the past 20 years considerable progress has been made in establishing the presence of metallic ions in the sporadic E layers at mid latitudes and as discrete patches at high altitudes in the equatorial ionosphere. The E-region observations have been based on rocket flights, which represent local conditions faithfully. But the global distribution of metallic ions and variations relating to changes in season, local time, magnetic activity, etc., which require satellite data, have been largely unexamined. This work presents a few aspects of this missing global distribution over an altitude range of 100 to 1000 km, using the data from AE-C, AE-D, and OGO-6 satellites and the rocket flights 18.117 and 18.118 from Wallops Island on July 12 and 13, 1971. The rocket data provide a day-night pair of vertical profiles that include altitudes not covered by the satellites. Results are presented for Mg + , Al + , Si + and Fe + ions in terms of their detection probabilities, median concentrations and relative abundances with respect to Mg + ions as a function of significant geophysical parameters. Na + and K + ions have been excluded from this study because alkali metal ions driven off the spacecraft hamper the measurement of ambient Na + and K + ions. This study has indicated that in general different metallic ions appear together in comparable concentrations except for Al + , which is an order of magnitude smaller than the others

  1. Analysis of metal ion release from biomedical implants

    Directory of Open Access Journals (Sweden)

    Ivana Dimić

    2013-06-01

    Full Text Available Metallic biomaterials are commonly used for fixation or replacement of damaged bones in the human body due to their good combination of mechanical properties. The disadvantage of metals as implant materials is their susceptibility to corrosion and metal ion release, which can cause serious health problems. In certain concentrations metals and metal ions are toxic and their presence can cause diverse inflammatory reactions, genetic mutations or even cancer. In this paper, different approaches to metal ion release examination, from biometallic materials sample preparation to research results interpretation, will be presented. An overview of the analytical techniques, used for determination of the type and concentration of released ions from implants in simulated biofluids, is also given in the paper.

  2. Amorphization of metals by ion implantation and ion beam mixing

    International Nuclear Information System (INIS)

    Rauschenbach, B.; Heera, V.

    1988-01-01

    Amorphous metallic systems can be formed either by high-fluence ion implantation of glassforming species or by irradiation of layered metal systems with inert gas ions. Both techniques and experimental examples are presented. Empirical rules are discussed which predict whether a given system can be transformed into an amorphous phase. Influence of temperature, implantation dose and pre-existing crystalline metal composition on amorphization is considered. Examples are given of the implantation induced amorphous structure, recrystallization and formation of quasicrystalline structures. (author)

  3. Pseudo ribbon metal ion beam source

    International Nuclear Information System (INIS)

    Stepanov, Igor B.; Ryabchikov, Alexander I.; Sivin, Denis O.; Verigin, Dan A.

    2014-01-01

    The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface

  4. Pseudo ribbon metal ion beam source.

    Science.gov (United States)

    Stepanov, Igor B; Ryabchikov, Alexander I; Sivin, Denis O; Verigin, Dan A

    2014-02-01

    The paper describes high broad metal ion source based on dc macroparticle filtered vacuum arc plasma generation with the dc ion-beam extraction. The possibility of formation of pseudo ribbon beam of metal ions with the parameters: ion beam length 0.6 m, ion current up to 0.2 A, accelerating voltage 40 kV, and ion energy up to 160 kV has been demonstrated. The pseudo ribbon ion beam is formed from dc vacuum arc plasma. The results of investigation of the vacuum arc evaporator ion-emission properties are presented. The influence of magnetic field strength near the cathode surface on the arc spot movement and ion-emission properties of vacuum-arc discharge for different cathode materials are determined. It was shown that vacuum-arc discharge stability can be reached when the magnetic field strength ranges from 40 to 70 G on the cathode surface.

  5. Depth concentrations of deuterium ions implanted into some pure metals and alloys

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Wisniewski, R.; Kitowski, K.; Wilczynska, T.; Hofman, A.; Kulikauskas, V.; Shiryaev, A.A.; Zubavichyus, Ya.V.

    2011-01-01

    Pure metals (Cu, Ti, Zr, V, Pd) and diluted Pd alloys (Pd-Ag, Pd-Pt, Pd-Ru, Pd-Rh) were implanted by 25-keV deuterium ions at fluences in the range (1.2-2.3) x 10 22 D + /m 2 . The post-treatment depth distributions of deuterium ions were measured 10 days and three months after the implantation by using Elastic Recoil Detection Analysis (ERDA) and Rutherford Backscattering (RBS). Comparison of the obtained results allowed us to make conclusions about relative stability of deuterium and hydrogen gases in pure metals and diluted Pd alloys. Very high diffusion rates of implanted deuterium ions from V and Pd pure metals and Pd alloys were observed. Small-angle X-ray scattering revealed formation of nanosized defects in implanted corundum and titanium

  6. Fungitoxicity of metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Somers, E

    1961-01-01

    The in vitro fungistatic activity of some twenty-four metal cations has been determine against Alternaria tenuis and Botrytis fabae. The metal salts, mainly nitrates, were tested in aqueous solution without added spore germination stimulant. The logarithm of the metal ion concentration at the ED 50 value has been found to conform to the exponenttial relationship with electronegativity proposed by Danielli and Davies (1951). These results are discussed in relation to the site of action of metal cations on the fungal cell.

  7. Accumulation of metal ions by pectinates

    Science.gov (United States)

    Deiana, S.; Deiana, L.; Palma, A.; Premoli, A.; Senette, C.

    2009-04-01

    The knowledge of the mechanisms which regulate the interactions of metal ions with partially methyl esterified linear polymers of α-1,4 linked D-galacturonic acid units (pectinates), well represented in the root inner and outer apoplasm, is of great relevance to understand the processes which control their accumulation at the soil-root interface as well as their mobilization by plant metabolites. Accumulation of a metal by pectinates can be affected by the presence of other metals so that competition or distribution could be expected depending on the similar or different affinity of the metal ions towards the binding sites, mainly represented by the carboxylate groups. In order to better understand the mechanism of accumulation in the apoplasm of several metal ions, the sorption of Cd(II), Zn(II), Cu(II), Pb(II) and Cr(III) by a Ca-polygalacturonate gel, used as model of the soil-root interface, with a degree of esterification of 18% (PGAE1) and 65% (PGAE2) was studied at pH 3.0, 4.0, 5.0 and 6.0 in the presence of CaCl2 2.5 mM.. The results show that sorption increases with increasing both the initial metal concentration and pH. A similar sorption trend was evidenced for Cu(II) and Pb(II) and for Zn(II) and Cd(II), indicating that the mechanism of sorption for these two ionic couples is quite different. As an example, at pH 6.0 and an initial metal concentration equal to 2.0 mM, the amount of Cu(II) and Pb(II) sorbed was about 1.98 mg-1 of PGAE1 while that of Cd(II) and Zn(II) was about 1.2 mg-1. Cr(III) showed a rather different sorption trend and a much higher amount (2.8 mg-1of PGAE1 at pH 6.0) was recorded. The higher affinity of Cr(III) for the polysaccharidic matrix is attributable to the formation of Cr(III) polynuclear species in solution, as shown by the distribution diagrams obtained through the MEDUSA software. On the basis of these findings, the following affinity towards the PGAE1 can be assessed: Cr(III) > Cu(II) ? Pb(II) > Zn (II) ? Cd

  8. Surface modification by metal ion implantation forming metallic nanoparticles in an insulating matrix

    International Nuclear Information System (INIS)

    Salvadori, M.C.; Teixeira, F.S.; Sgubin, L.G.; Cattani, M.; Brown, I.G.

    2014-01-01

    Highlights: • Metal nanoparticles can be produced through metallic ion implantation in insulating substrate, where the implanted metal self-assembles into nanoparticles. • The nanoparticles nucleate near the maximum of the implantation depth profile, that can be estimated by computer simulation using the TRIDYN. • Nanocomposites, obtained by this way, can be produced in different insulator materials. More specifically we have studied Au/PMMA (polymethylmethacrylate), Pt/PMMA, Ti/alumina and Au/alumina systems. • The nanocomposites were characterized by measuring the resistivity of the composite layer as function of the dose implanted, reaching the percolation threshold. • Excellent agreement was found between the experimental results and the predictions of the theory. - Abstract: There is special interest in the incorporation of metallic nanoparticles in a surrounding dielectric matrix for obtaining composites with desirable characteristics such as for surface plasmon resonance, which can be used in photonics and sensing, and controlled surface electrical conductivity. We have investigated nanocomposites produced by metal ion implantation into insulating substrates, where the implanted metal self-assembles into nanoparticles. The nanoparticles nucleate near the maximum of the implantation depth profile (projected range), which can be estimated by computer simulation using the TRIDYN code. TRIDYN is a Monte Carlo simulation program based on the TRIM (Transport and Range of Ions in Matter) code that takes into account compositional changes in the substrate due to two factors: previously implanted dopant atoms, and sputtering of the substrate surface. Our study show that the nanoparticles form a bidimentional array buried a few nanometers below the substrate surface. We have studied Au/PMMA (polymethylmethacrylate), Pt/PMMA, Ti/alumina and Au/alumina systems. Transmission electron microscopy of the implanted samples show that metallic nanoparticles form in

  9. Upgraded vacuum arc ion source for metal ion implantation

    International Nuclear Information System (INIS)

    Nikolaev, A. G.; Oks, E. M.; Savkin, K. P.; Yushkov, G. Yu.; Brown, I. G.

    2012-01-01

    Vacuum arc ion sources have been made and used by a large number of research groups around the world over the past twenty years. The first generation of vacuum arc ion sources (dubbed ''Mevva,'' for metal vapor vacuum arc) was developed at Lawrence Berkeley National Laboratory in the 1980s. This paper considers the design, performance parameters, and some applications of a new modified version of this kind of source which we have called Mevva-V.Ru. The source produces broad beams of metal ions at an extraction voltage of up to 60 kV and a time-averaged ion beam current in the milliampere range. Here, we describe the Mevva-V.Ru vacuum arc ion source that we have developed at Tomsk and summarize its beam characteristics along with some of the applications to which we have put it. We also describe the source performance using compound cathodes.

  10. Yeast enolase: mechanism of activation by metal ions.

    Science.gov (United States)

    Brewer, J M

    1981-01-01

    Yeast enolase as prepared by current procedures is inherently chemically homogeneous, though deamidation and partial denaturation can produce electrophoretically distinct forms. A true isozyme of the enzyme exists but does not survive the purification procedure. The chemical sequence for both has been established. The enzyme behaves in solution like a compact, nearly spherical molecule of moderate hydration. Strong intramolecular forces maintain the structure of the individual subunits. The enzyme as isolated is dimeric. If dissociated in the presence of magnesium ions and substrate, then the subunits are active, but if the dissociation occurs in the absence of metal ions, they are inactive until they have reassociated and undergone a first order "annealing" process. Magnesium (II) enhances association. The interaction between the subunits is hydrophobic in character. The enzyme can bind up to 2 mol of most metal ions in "conformational" sites which then allows up to 2 mol of substrate or some substrate analogue to bind. This is not sufficient for catalysis, but conformational metal ions do more than just allow substrate binding. A change in the environment of the metal ions occurs on substrate or substrate analogue binding. There is an absolute correlation between the occurrence of a structural change undergone by the 3-amino analogue of phosphoenolpyruvate and whether the metal ions produce any level of enzymatic activity. For catalysis, two more moles of metal ions, called "catalytic", must bind. There is evidence that the enzymatic reaction involves a carbanion mechanism. It is likely that two more moles of metal ion can bind which inhibit the reaction. The requirement for 2 mol of metal ion per subunit which contribute in different ways to catalysis is exhibited by a number of other enzymes.

  11. Ionic Liquids as Extraction Media for Metal Ions

    Science.gov (United States)

    Hirayama, Naoki

    In solvent extraction separation of metal ions, recently, many researchers have investigated possible use of hydrophobic ionic liquids as extraction media instead of organic solvents. Ionic liquids are salts of liquid state around room temperature and can act not only as solvents but also as ion-exchangers. Therefore, the extraction mechanism of metal ions into ionic liquids is complicated. This review presents current overview and perspective on evaluation of nature of hydrophobic ionic liquids as extraction media for metal ions.

  12. Oxidation of cyclohexane catalyzed by metal-ion-exchanged zeolites.

    Science.gov (United States)

    Sökmen, Ilkay; Sevin, Fatma

    2003-08-01

    The ion-exchange rates and capacities of the zeolite NaY for the Cu(II), Co(II), and Pb(II) metal ions were investigated. Ion-exchange equilibria were achieved in approximately 72 h for all the metal ions. The maximum ion exchange of metal ions into the zeolite was found to be 120 mg Pb(II), 110 mg Cu(II), and 100 mg Co(II) per gram of zeolite NaY. It is observed that the exchange capacity of a zeolite varies with the exchanged metal ion and the amount of metal ions exchanged into zeolite decreases in the sequence Pb(II) > Cu(II) > Co(II). Application of the metal-ion-exchanged zeolites in oxidation of cyclohexane in liquid phase with visible light was examined and it is observed that the order of reactivity of the zeolites for the conversion of cyclohexane to cyclohexanone and cyclohexanol is CuY > CoY > PbY. It is found that conversion increases by increase of the empty active sites of a zeolite and the formation of cyclohexanol is favored initially, but the cyclohexanol is subsequently converted to cyclohexanone.

  13. Selective transport of metal ions through cation exchange membrane in the presence of a complexing agent

    Energy Technology Data Exchange (ETDEWEB)

    Tingchia Huang; Jaukai Wang (National Cheng Kung Univ., Tainan (Taiwan, Province of China))

    1993-01-01

    Selective transport of metal ions through a cation exchange membrane was studied in stirred batch dialyzer for the systems Ni[sup 2+]-Cu[sup 2+] and Cu[sup 2+]-Fe[sup 3+]. Oxalic acid, malonic acid, citric acid, glycine, and ethylenediaminetetraacetic acid were employed as the complexing agents added in the feed solution in order to increase the permselectivity of metal ions. The experimental results show that the selective transport behavior of metal ions depends on the valence and the concentration of metal ions, the stoichiometric ratio of complexing agent to metal ions, and the pH value of the feed solution, but is independent of the concentration of counterion in the stripping phase. A theoretical approach was formulated on the basis of the Nernst-Planck equation and interface quasi-equilibrium. Theoretical solutions obtained from numerical calculation were in agreement with the experimental data.

  14. Metal ion interaction with phosphorylated tyrosine analogue monolayers on gold.

    Science.gov (United States)

    Petoral, Rodrigo M; Björefors, Fredrik; Uvdal, Kajsa

    2006-11-23

    Phosphorylated tyrosine analogue molecules (pTyr-PT) were assembled onto gold substrates, and the resulting monolayers were used for metal ion interaction studies. The monolayers were characterized by X-ray photoelectron spectroscopy (XPS), infrared reflection-absorption spectroscopy (IRAS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), both prior to and after exposure to metal ions. XPS verified the elemental composition of the molecular adsorbate and the presence of metal ions coordinated to the phosphate groups. Both the angle-dependent XPS and IRAS results were consistent with the change in the structural orientation of the pTyr-PT monolayer upon exposure to metal ions. The differential capacitance of the monolayers upon coordination of the metal ions was evaluated using EIS. These metal ions were found to significantly change the capacitance of the pTyr-PT monolayers in contrast to the nonphosphorylated tyrosine analogue (TPT). CV results showed reduced electrochemical blocking capabilities of the phosphorylated analogue monolayer when exposed to metal ions, supporting the change in the structure of the monolayer observed by XPS and IRAS. The largest change in the structure and interfacial capacitance was observed for aluminum ions, compared to calcium, magnesium, and chromium ions. This type of monolayer shows an excellent capability to coordinate metal ions and has a high potential for use as sensing layers in biochip applications to monitor the presence of metal ions.

  15. Ion implantation and ion assisted coatings for wear resistance in metals

    International Nuclear Information System (INIS)

    Dearnaley, G.

    1986-01-01

    The implantation of electrically accelerated ions of chosen elements into the surface of material provides a method for improving surface properties such as wear resistance. High concentrations of nitrogen implanted into metals create obstacles to dislocation movement, and certain combinations of metallic and non-metallic species will also strengthen the surface. The process is best applied to situations involving mild abrasive wear and operating temperatures that are not too high. Some dramatic increases in life have been reported under such favourable conditions. A more recent development has been the combination of a thin coating with reactive ion bombardment designed to enhance adhesion by ion mixing at the interface and so provide hardness by the formation of finely dispersed nitrides, including cubic boron nitride. These coatings often possess vivid and decorative colours as an added benefit. Developments in the equipment for industrial ion implantation now offer more attractive costs per unit area and a potentially greater throughput of work. A versatile group of related hard vacuum treatments is now emerging, involving the use of intense beams of nitrogen ions for the purpose of tailoring metal surfaces to resist wear. (author)

  16. Metal ion-dependent DNAzymes and their applications as biosensors.

    Science.gov (United States)

    Lan, Tian; Lu, Yi

    2012-01-01

    Long considered to serve solely as the genetic information carrier, DNA has been shown in 1994 to be able to act as DNA catalysts capable of catalyzing a trans-esterification reaction similar to the action of ribozymes and protein enzymes. Although not yet found in nature, numerous DNAzymes have been isolated through in vitro selection for catalyzing many different types of reactions in the presence of different metal ions and thus become a new class of metalloenzymes. What remains unclear is how DNA can carry out catalysis with simpler building blocks and fewer functional groups than ribozymes and protein enzymes and how DNA can bind metal ions specifically to perform these functions. In the past two decades, many biochemical and biophysical studies have been carried out on DNAzymes, especially RNA-cleaving DNAzymes. Important insights have been gained regarding their metal-dependent activity, global folding, metal binding sites, and catalytic mechanisms for these DNAzymes. Because of their high metal ion selectivity, one of the most important practical applications for DNAzymes is metal ion detection, resulting in highly sensitive and selective fluorescent, colorimetric, and electrochemical sensors for a wide range of metal ions such as Pb(2+), UO2 2 +,[Formula: see text] including paramagnetic metal ions such as Cu(2+). This chapter summarizes recent progresses in in vitro selection of metal ion-selective DNAzymes, their biochemical and biophysical studies and sensing applications.

  17. Mechanism of Metal Ion Activation of the Diphtheria Toxin Repressor DtxR

    Energy Technology Data Exchange (ETDEWEB)

    D' Aquino,J.; Tetenbaum-Novatt, J.; White, A.; Berkovitch, F.; Ringe, D.

    2005-01-01

    The diphtheria toxin repressor (DtxR) is a metal ion-activated transcriptional regulator that has been linked to the virulence of Corynebacterium diphtheriae. Structure determination has shown that there are two metal ion binding sites per repressor monomer, and site-directed mutagenesis has demonstrated that binding site 2 (primary) is essential for recognition of the target DNA repressor, leaving the role of binding site 1 (ancillary) unclear. Calorimetric techniques have demonstrated that although binding site 1 (ancillary) has high affinity for metal ion with a binding constant of 2 x 10{sup -7}, binding site 2 (primary) is a low-affinity binding site with a binding constant of 6.3 x 10{sup -4}. These two binding sites act in an independent fashion, and their contribution can be easily dissected by traditional mutational analysis. Our results clearly demonstrate that binding site 1 (ancillary) is the first one to be occupied during metal ion activation, playing a critical role in stabilization of the repressor. In addition, structural data obtained for the mutants Ni-DtxR(H79A, C102D), reported here, and the previously reported DtxR(H79A) have allowed us to propose a mechanism of metal activation for DtxR.

  18. State promotion and neutralization of ions near metal surface

    International Nuclear Information System (INIS)

    Zinoviev, A.N.

    2011-01-01

    Research highlights: → Multiply charged ion and the charge induced in the metal form a dipole. → Dipole states are promoted into continuum with decreasing ion-surface distance. → These states cross the states formed from metal atom. → Proposed model explains the dominant population of deep bound states. → Observed spectra of emitted Auger electrons prove this promotion model. -- Abstract: When a multiply charged ion with charge Z approaches the metal surface, a dipole is formed by the multiply charged ion and the charge induced in the metal. The states for such a dipole are promoted into continuum with decreasing ion-surface distance and cross the states formed from metal atom. The model proposed explains the dominant population of deep bound states in collisions considered.

  19. Modification of medical metals by ion implantation of copper

    Science.gov (United States)

    Wan, Y. Z.; Xiong, G. Y.; Liang, H.; Raman, S.; He, F.; Huang, Y.

    2007-10-01

    The effect of copper ion implantation on the antibacterial activity, wear performance and corrosion resistance of medical metals including 317 L of stainless steels, pure titanium, and Ti-Al-Nb alloy was studied in this work. The specimens were implanted with copper ions using a MEVVA source ion implanter with ion doses ranging from 0.5 × 10 17 to 4 × 10 17 ions/cm 2 at an energy of 80 keV. The antibacterial effect, wear rate, and inflexion potential were measured as a function of ion dose. The results obtained indicate that copper ion implantation improves the antibacterial effect and wear behaviour for all the three medical materials studied. However, corrosion resistance decreases after ion implantation of copper. Experimental results indicate that the antibacterial property and corrosion resistance should be balanced for medical titanium materials. The marked deteriorated corrosion resistance of 317 L suggests that copper implantation may not be an effective method of improving its antibacterial activity.

  20. Structure of liquid alkali metals as electron-ion plasmas

    International Nuclear Information System (INIS)

    Chaturvedi, D.K.; Senatore, G.; Tosi, M.P.

    1980-08-01

    The static structure factor of liquid alkali metals near freezing, and its dependence on temperature and pressure, are evaluated in an electron-ion plasma model from an accurate theoretical determination of the structure factor of the one-component classical plasma and electron-screening theory. Very good agreement is obtained with the available experimental data. (author)

  1. Ion spectra of the metal vapor vacuum arc ion source with compound and alloy cathodes

    Science.gov (United States)

    Sasaki, Jun; Brown, Ian G.

    1990-01-01

    In metal vapor vacuum arc (MEVVA) ion sources, vacuum arc plasma with cathodes of single, pure elements has been utilized for the production of metal ions. In this study, we have investigated the charge state distributions of ions produced in vacuum arc plasmas in a MEVVA ion source for the case when the cathode is an alloy or a compound material. The ion charge state spectra were analyzed by means of a time-of-flight apparatus. We have compared the ion spectra for a cathode of an alloy or a compound material with its constituent elements: TiC/TiN/TiO2/Ti/C, SiC/Si/C, WC/W/C U/UN/(UN-ZrC)/Zr/C, and brass/Zn/Cu. We find that the MEVVA produces ions of all constituent elements in the compound and the alloy cathodes. The charge state distribution of each element differs, however, from the charge state distribution obtained in the vacuum arc with a cathode made of the pure, single constituent element. Fractional values of the total ion numbers of each constituent element in the extracted beam depart from the stoichiometry of the elements in the cathode material. In an operation with a TiC cathode, we irradiated a 304 stainless-steel plate with the extracted beam. Results from glow-discharge spectroscopy (GDS) of the surface show that both titanium and carbon are implanted in the substrate after the irradiation.

  2. Comparative study of metal and non-metal ion implantation in polymers: Optical and electrical properties

    International Nuclear Information System (INIS)

    Resta, V.; Quarta, G.; Farella, I.; Maruccio, L.; Cola, A.; Calcagnile, L.

    2014-01-01

    The implantation of 1 MeV metal ( 63 Cu + , 107 Ag + , 197 Au + ) and non-metal ( 4 He + , 12 C + ) ions in a polycarbonate (PC) matrix has been studied in order to evaluate the role of ion species in the modification of optical and electrical properties of the polymer. When the ion fluence is above ∼1 × 10 13 ions cm −2 , the threshold for latent tracks overlapping is overcome and π-bonded carbon clusters grow and aggregate forming a network of conjugated C=C bonds. For fluences around 1 × 10 17 ions cm −2 , the aggregation phenomena induce the formation of amorphous carbon and/or graphite like structures. At the same time, nucleation of metal nanoparticles (NPs) from implanted species can take place when the supersaturation threshold is overcome. The optical absorption of the samples increases in the visible range and the optical band gap redshifts from 3.40 eV up to 0.70 eV mostly due to the carbonization process and the formation of C 0x clusters and cluster aggregates. Specific structures in the extinction spectra are observed when metal ions are selected in contrast to the non-metal ion implanted PC, thus revealing the possible presence of noble metal based NPs interstitial to the C 0x cluster network. The corresponding electrical resistance decreases much more when metal ions are implanted with at least a factor of 2 orders of magnitude difference than the non-metal ions based samples. An absolute value of ∼10 7 Ω/sq has been measured for implantation with metals at doses higher than 5 × 10 16 ions cm −2 , being 10 17 Ω/sq the corresponding sheet resistance for pristine PC

  3. Comparative study of metal and non-metal ion implantation in polymers: Optical and electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Resta, V., E-mail: vincenzo.resta@le.infn.it [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Quarta, G. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Farella, I. [Institute for Microelectronics and Microsystems – Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Maruccio, L. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy); Cola, A. [Institute for Microelectronics and Microsystems – Unit of Lecce, National Council of Research (IMM/CNR), Lecce I-73100 (Italy); Calcagnile, L. [Department of Engineering for Innovation, University of Salento, Via Monteroni, Lecce I-73100 (Italy)

    2014-07-15

    The implantation of 1 MeV metal ({sup 63}Cu{sup +}, {sup 107}Ag{sup +}, {sup 197}Au{sup +}) and non-metal ({sup 4}He{sup +}, {sup 12}C{sup +}) ions in a polycarbonate (PC) matrix has been studied in order to evaluate the role of ion species in the modification of optical and electrical properties of the polymer. When the ion fluence is above ∼1 × 10{sup 13} ions cm{sup −2}, the threshold for latent tracks overlapping is overcome and π-bonded carbon clusters grow and aggregate forming a network of conjugated C=C bonds. For fluences around 1 × 10{sup 17} ions cm{sup −2}, the aggregation phenomena induce the formation of amorphous carbon and/or graphite like structures. At the same time, nucleation of metal nanoparticles (NPs) from implanted species can take place when the supersaturation threshold is overcome. The optical absorption of the samples increases in the visible range and the optical band gap redshifts from 3.40 eV up to 0.70 eV mostly due to the carbonization process and the formation of C{sub 0x} clusters and cluster aggregates. Specific structures in the extinction spectra are observed when metal ions are selected in contrast to the non-metal ion implanted PC, thus revealing the possible presence of noble metal based NPs interstitial to the C{sub 0x} cluster network. The corresponding electrical resistance decreases much more when metal ions are implanted with at least a factor of 2 orders of magnitude difference than the non-metal ions based samples. An absolute value of ∼10{sup 7} Ω/sq has been measured for implantation with metals at doses higher than 5 × 10{sup 16} ions cm{sup −2}, being 10{sup 17} Ω/sq the corresponding sheet resistance for pristine PC.

  4. Factorial experimental design for recovering heavy metals from sludge with ion-exchange resin

    International Nuclear Information System (INIS)

    Lee, I.H.; Kuan, Y.-C.; Chern, J.-M.

    2006-01-01

    Wastewaters containing heavy metals are usually treated by chemical precipitation method in Taiwan. This method can remove heavy metals form wastewaters efficiently, but the resultant heavy metal sludge is classified as hazardous solid waste and becomes another environmental problem. If we can remove heavy metals from sludge, it becomes non-hazardous waste and the treatment cost can be greatly reduced. This study aims at using ion-exchange resin to remove heavy metals such as copper, zinc, cadmium, and chromium from sludge generated by a PCB manufacturing plant. Factorial experimental design methodology was used to study the heavy metal removal efficiency. The total metal concentrations in the sludge, resin, and solution phases were measured respectively after 30 min reaction with varying leaching agents (citric acid and nitric acid); ion-exchange resins (Amberlite IRC-718 and IR-120), and temperatures (50 and 70 deg. C). The experimental results and statistical analysis show that a stronger leaching acid and a higher temperature both favor lower heavy metal residues in the sludge. Two-factors and even three-factor interaction effects on the heavy metal sorption in the resin phase are not negligible. The ion-exchange resin plays an important role in the sludge extraction or metal recovery. Empirical regression models were also obtained and used to predict the heavy metal profiles with satisfactory results

  5. Pseudoclassical approach to electron and ion density correlations in simple liquid metals

    International Nuclear Information System (INIS)

    Vericat, F.; Tosi, M.P.; Pastore, G.

    1986-04-01

    Electron-electron and electron-ion structural correlations in simple liquid metals are treated by using effective pair potentials to incorporate quantal effects into a pseudoclassical description of the electron fluid. An effective pair potential between simultaneous electron density fluctuations is first constructed from known properties of the degenerate jellium model, which are the plasmon sum rule, the Kimball-Niklasson relation and Yasuhara's values of the electron pair distribution function at contact. An analytic expression is thereby obtained in the Debye-Hueckel approximation for the electronic structure factor in jellium over a range of density appropriate to metals, with results which compare favourably with those of fully quantal evaluations. A simple pseudoclassical model is then set up for a liquid metal: this involves a model of charged hard spheres for the ion-ion potential and an empty core model for the electron-ion potential, the Coulombic tails being scaled as required by the relation between the long-wavelength partial structure factors and the isothermal compressibility of the metal. The model is solved analytically by a pseudoclassical linear response treatment of the electron-ion coupling and numerical results are reported for partial structure factors in liquid sodium and liquid beryllium. Contact is made for the latter system with data on the electron-electron structure factor in the crystal from inelastic X-ray scattering experiments of Eisenberger, Marra and Brown. (author)

  6. Solution chemistry and separation of metal ions in leached solution

    International Nuclear Information System (INIS)

    Shibata, J.

    1991-01-01

    The method to presume a dissolved state of metal ions in an aqueous solution and the technology to separate and concentrate metal ions in a leached solution are described in this paper. It is very important for the separation of metal ions to know the dissolved state of metal ions. If we know the composition of an aqueous solution and the stability constants of metal-ligand complexes, we can calculate and estimate the concentration of each species in the solution. Then, we can decide the policy to separate and concentrate metal ions. There are several methods for separation and purification; hydroxide precipitation method, sulfide precipitation method, solvent extraction method and ion exchange resin method. Solvent extraction has been used in purification processes of copper refinery, uranium refinery, platinum metal refinery and rare earth metal refinery. Fundamental process of solvent extraction, a kind of commercial extractants, a way of determining a suitable extractant and an equipment are discussed. Finally, it will be emphasized how the separation of rare earths is improved in solvent extraction. (author) 21 figs., 8 tabs., 8 refs

  7. Density functional study of isoguanine tetrad and pentad sandwich complexes with alkali metal ions.

    Science.gov (United States)

    Meyer, Michael; Steinke, Thomas; Sühnel, Jürgen

    2007-02-01

    Isoguanine tetraplexes and pentaplexes contain two or more stacked polyads with intercalating metal ions. We report here the results of a density functional study of sandwiched isoguanine tetrad and pentad complexes consisting of two polyads with Na(+), K(+) and Rb(+) ions at the B3LYP level. In comparison to single polyad metal ion complexes, there is a trend towards increased non-planarity of the polyads in the sandwich complexes. In general, the pentad sandwiches have relatively planar polyad structures, whereas the tetrad complexes contain highly non-planar polyad building blocks. As in other sandwich complexes and in metal ion complexes with single polyads, the metal ion-base interaction energy plays an essential role. In iG sandwich structures, this interaction energy is slightly larger than in the corresponding guanine sandwich complexes. Because the base-base interaction energy is even more increased in passing from guanine to isoguanine, the isoguanine sandwiches are thus far the only examples where the base-base interaction energy is larger than the base-metal ion interaction energy. Stacking interactions have been studied in smaller models consisting of two bases, retaining the geometry from the complete complex structures. From the data obtained at the B3LYP and BH&H levels and with Møller-Plesset perturbation theory, one can conclude that the B3LYP method overestimates the repulsion in stacked base dimers. For the complexes studied in this work, this is only of minor importance because the direct inter-tetrad or inter-pentad interaction is supplemented by a strong metal ion-base interaction. Using a microsolvation model, the metal ion preference K(+) approximately Rb(+) > Na(+) is found for tetrad complexes. On the other hand, for pentads the ordering is Rb(+) > K(+) > Na(+). In the latter case experimental data are available that agree with this prediction.

  8. Development of a four-zone carousel process packed with metal ion-imprinted polymer for continuous separation of copper ions from manganese ions, cobalt ions, and the constituent metal ions of the buffer solution used as eluent.

    Science.gov (United States)

    Jo, Se-Hee; Park, Chanhun; Yi, Sung Chul; Kim, Dukjoon; Mun, Sungyong

    2011-08-19

    A three-zone carousel process, in which Cu(II)-imprinted polymer (Cu-MIP) and a buffer solution were employed as adsorbent and eluent respectively, has been developed previously for continuous separation of Cu²⁺ (product) from Mn²⁺ and Co²⁺ (impurities). Although this process was reported to be successful in the aforementioned separation task, the way of using a buffer solution as eluent made it inevitable that the product stream included the buffer-related metal ions (i.e., the constituent metal ions of the buffer solution) as well as copper ions. For a more perfect recovery of copper ions, it would be necessary to improve the previous carousel process such that it can remove the buffer-related metal ions from copper ions while maintaining the previous function of separating copper ions from the other 2 impure heavy-metal ions. This improvement was made in this study by proposing a four-zone carousel process based on the following strategy: (1) the addition of one more zone for performing the two-step re-equilibration tasks and (2) the use of water as the eluent of the washing step in the separation zone. The operating conditions of such a proposed process were determined on the basis of the data from a series of single-column experiments. Under the determined operating conditions, 3 runs of carousel experiments were carried out. The results of these experiments revealed that the feed-loading time was a key parameter affecting the performance of the proposed process. Consequently, the continuous separation of copper ions from both the impure heavy-metal ions and the buffer-related metal ions could be achieved with a purity of 91.9% and a yield of 92.8% by using the proposed carousel process based on a properly chosen feed-loading time. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Rechargeable dual-metal-ion batteries for advanced energy storage.

    Science.gov (United States)

    Yao, Hu-Rong; You, Ya; Yin, Ya-Xia; Wan, Li-Jun; Guo, Yu-Guo

    2016-04-14

    Energy storage devices are more important today than any time before in human history due to the increasing demand for clean and sustainable energy. Rechargeable batteries are emerging as the most efficient energy storage technology for a wide range of portable devices, grids and electronic vehicles. Future generations of batteries are required to have high gravimetric and volumetric energy, high power density, low price, long cycle life, high safety and low self-discharge properties. However, it is quite challenging to achieve the above properties simultaneously in state-of-the-art single metal ion batteries (e.g. Li-ion batteries, Na-ion batteries and Mg-ion batteries). In this contribution, hybrid-ion batteries in which various metal ions simultaneously engage to store energy are shown to provide a new perspective towards advanced energy storage: by connecting the respective advantages of different metal ion batteries they have recently attracted widespread attention due to their novel performances. The properties of hybrid-ion batteries are not simply the superposition of the performances of single ion batteries. To enable a distinct description, we only focus on dual-metal-ion batteries in this article, for which the design and the benefits are briefly discussed. We enumerate some new results about dual-metal-ion batteries and demonstrate the mechanism for improving performance based on knowledge from the literature and experiments. Although the search for hybrid-ion batteries is still at an early age, we believe that this strategy would be an excellent choice for breaking the inherent disadvantages of single ion batteries in the near future.

  10. Breast milk metal ion levels in a young and active patient with a metal-on-metal hip prosthesis.

    Science.gov (United States)

    Nelis, Raymond; de Waal Malefijt, Jan; Gosens, Taco

    2013-01-01

    Metal-on-metal resurfacing arthroplasty of the hip has been used increasingly over the last 10 years in younger active patients. The dissolution of the metal wear particles results in measurable increases in cobalt and chromium ions in the serum and urine of patients with a metal-on-metal bearing. We measured the cobalt, chromium, and molybdenum ion levels in urine; serum; and breast milk in a young and active patient with a metal-on-metal hip prosthesis after a pathologic fracture of the femoral neck. Metal-on-metal hip prosthesis leads to increasing levels of molybdenum in breast milk in the short-term follow-up. There are no increasing levels of chromium and cobalt ions in breast milk. Besides the already known elevated concentrations in serum of chromium and cobalt after implantation of a metal-on-metal hip prosthesis, we found no increasing levels of chromium and cobalt in urine. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Extracting metal ions with diphosphonic acid, or derivative thereof

    Science.gov (United States)

    Horwitz, Earl P.; Gatrone, Ralph C.; Nash, Kenneth L.

    1994-01-01

    Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulphur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described.

  12. Electrical properties of polymer modified by metal ion implantation

    International Nuclear Information System (INIS)

    Wu Yuguang; Zhang Tonghe; Zhang Huixing; Zhang Xiaoji; Deng Zhiwei; Zhou Gu

    2000-01-01

    Polyethylene terephthalate (PET) has been modified by Ag, Cr, Cu and Si ion implantation with a dose range from 1x10 16 to 2x10 17 ions cm -2 using a metal vapor vacuum arc (MEVVA) source. The electrical properties of PET have been changed after metal ion implantation. The resistivity of implanted PET decreased obviously with an increase of ion dose. When metal ion dose of 2x10 17 cm -2 was selected, the resistivity of PET could be less than 10 Ω cm, but when Si ions are implanted, the resistivity of PET would be up to several hundred Ω cm. The results show that the conductive behavior of a metal ion implanted sample is obviously different from Si implantation one. The changes of the structure and composition have been observed with transmission electron microscope (TEM) and X-ray diffraction (XRD). The surface structure is varying after ion implantation and it is believed that the change would cause the improvement of the conductive properties. The mechanism of electrical conduction will be discussed

  13. Oxide-nitride-oxide dielectric stacks with Si nanoparticles obtained by low-energy ion beam synthesis

    International Nuclear Information System (INIS)

    Ioannou-Sougleridis, V; Dimitrakis, P; Vamvakas, V Em; Normand, P; Bonafos, C; Schamm, S; Mouti, A; Assayag, G Ben; Paillard, V

    2007-01-01

    Formation of a thin band of silicon nanoparticles within silicon nitride films by low-energy (1 keV) silicon ion implantation and subsequent thermal annealing is demonstrated. Electrical characterization of metal-insulator-semiconductor capacitors reveals that oxide/Si-nanoparticles-nitride/oxide dielectric stacks exhibit enhanced charge transfer characteristics between the substrate and the silicon nitride layer compared to dielectric stacks using unimplanted silicon nitride. Attractive results are obtained in terms of write/erase memory characteristics and data retention, indicating the large potential of the low-energy ion-beam-synthesis technique in SONOS memory technology

  14. Improving Passivation Process of Si Nanocrystals Embedded in SiO2 Using Metal Ion Implantation

    Directory of Open Access Journals (Sweden)

    Jhovani Bornacelli

    2013-01-01

    Full Text Available We studied the photoluminescence (PL of Si nanocrystals (Si-NCs embedded in SiO2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm inside the SiO2 achieving a robust and better protected system. After metal ion implantation (Ag or Au, and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H2/N2 and Ar to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

  15. [Bioregeneration of the solutions obtained during the leaching of nonferrous metals from waste slag by acidophilic microorganisms].

    Science.gov (United States)

    Fomchenko, N V; Murav'ev, M I; Kondrat'eva, T F

    2014-01-01

    The bioregeneration of the solutions obtained after the leaching of copper and zinc from waste slag by sulfuric solutions of ferric sulfate is examined. For bioregeneration, associations of mesophilic and moderately thermqophilic acidophilic chemolithotrophic microorganisms were made. It has been shown that the complete oxidation of iron ions in solutions obtained after the leaching of nonferrous metals from waste slag is possible at a dilution of the pregnant solution with a nutrient medium. It has been found that the maximal rate of oxidation of iron ions is observed at the use of a mesophilic association of microorganisms at a threefold dilution of the pregnant solution with a nutrient medium. The application ofbioregeneration during the production of nonferrous metals from both waste and converter slags would make it possible to approach the technology of their processing using the closed cycle of workflows.

  16. Extracting metal ions with diphosphonic acid, or derivative thereof

    Science.gov (United States)

    Horwitz, E.P.; Gatrone, R.C.; Nash, K.L.

    1994-07-26

    Thermodynamically-unstable complexing agents which are diphosphonic acids and diphosphonic acid derivatives (or sulfur containing analogs), like carboxyhydroxymethanediphosphonic acid and vinylidene-1,1-diphosphonic acid, are capable of complexing with metal ions, and especially metal ions in the II, III, IV, V and VI oxidation states, to form stable, water-soluble metal ion complexes in moderately alkaline to highly-acidic media. However, the complexing agents can be decomposed, under mild conditions, into non-organic compounds which, for many purposes are environmentally-nondamaging compounds thereby degrading the complex and releasing the metal ion for disposal or recovery. Uses for such complexing agents as well as methods for their manufacture are also described. 1 fig.

  17. Designer ligands: The search for metal ion selectivity

    Directory of Open Access Journals (Sweden)

    Perry T. Kaye

    2011-03-01

    Full Text Available The paper reviews research conducted at Rhodes University towards the development of metal-selective ligands. The research has focused on the rational design, synthesis and evaluation of novel ligands for use in the formation of copper complexes as biomimetic models of the metalloenzyme, tyrosinase, and for the selective extraction of silver, nickel and platinum group metal ions in the presence of contaminating metal ions. Attention has also been given to the development of efficient, metal-selective molecular imprinted polymers.

  18. Field-emission liquid-metal ion source and triode ion gun

    International Nuclear Information System (INIS)

    Komuro, M.; Kawakatsu, H.

    1981-01-01

    A pointed-filament-type field-emission liquid-metal ion source is designed and employed as a gold ion source. By adding a crossbar across a hairpin bend, the amount of the gold adhering on the filament is increased. The lifetime is estimated to be over 200 h at 10-mA emission current. The emission current increases with increasing extraction voltage up to a saturation value which is ascribed to a limitation of the supply of liquid gold to the needle apex. The value of current density per unit solid angle is 30 mA/sr at a total current of 30 mA, which is of the same order as that obtained from a gallium ion source previously reported. Emission current fluctuations of a few tens of percent of the dc component are observed. In order to regulate the emission current and suppress current fluctuations, a bias electrode in addition to a counterelectrode is placed close to the needle apex. With such a triode structure, the emission current is regulated by a bias voltage of several hundred volts and stabilized to within 1% by means of feedback to the bias voltage of a current monitor output

  19. Ion microprobe analysis of metallic pigments

    International Nuclear Information System (INIS)

    Pelicon, P.; Simcic, J.; Budnar, M.; Klanjsek-Gunde, M.; Kunavaer, M.

    2001-01-01

    Full text: Metallic paints consist of metallic flakes dispersed m a resinous binder, i.e. a light-element polymer matrix. The spatial distribution and orientation of metallic flakes inside the matrix determines the covering efficiency of the paint, glossiness, and its angular-dependent properties such as lightness flop or color flop (two-tone). Such coatings are extensively used for a functional (i.e. security) as well as decorative purpose. The ion microbeam analysis of two types of silver paint with imbedded metallic flake has been performed to test the ability of the ion microbeam spectroscopic methods on this type of samples. The average sizes of the aluminium flakes were 23 (size distribution 10-37) and 49 (size distribution 34-75) micrometers, respectively. The proton beam with the size of 2x2 micrometers at Ljubljana ion microprobe has been used to scan the surface of the pigments. PIXE mapping of Al Kα map shows lateral distribution of the aluminum flakes, whereas the RBS slicing method reveals tomographic image of the flakes in uppermost 5 micrometers of the pigment layer. The flake distribution in the larger layer depths has been accessed by RBS analysis in a point mode. (author)

  20. Application of β-cyclodextrin polymers in separation of metal ions

    International Nuclear Information System (INIS)

    Kozlowski, C.A.; Kozlowska, J.

    2006-01-01

    In the present work the competitive transport of Cu(II), Co(II), Ni(II) and Zn(II) ions through the plasticized immobilized membranes was studied. β-cyclodextrin (β-CD) polymers have been used as macrocyclic ligands for separation of metal ions from dilute aqueous solutions by ion exchange methods, i.e. transport across polymer inclusion membranes and ion flotation process. β-CD polymers were prepared by cross-linking β-CD with alkenyl (nonenyl) succinic anhydride derivatives, phtalic and 3-nitrophtalic anhydride in anhydrous N,N-dimethylformamide (DMF) resulting in formation of Polymer A, B or C, respectively. In he case of cooper(II) flotation results obtained with the use of nonylphenol polyoxyethyl glycol ether as an non-anionic surfactant and β-CD polymers as complexation agent, show that the removal of metal decreases with higher molecular mass of β-CD polymers linked by phtalic or 3-nitrophtalic anhydrides. For both derivatives with pH increase the copper(II) removed increase. The highest flotation removal, i.e. 93% is observed for β-CD polymers synthesized at 100 o C with molar ratio CD : NaH : 3-nitrophtalic anhydride equal to 1 : 7 : 7

  1. Chromium and cobalt ion concentrations in blood and serum following various types of metal-on-metal hip arthroplasties

    DEFF Research Database (Denmark)

    Jantzen, Christopher; Jørgensen, Henrik L; Duus, Benn R

    2013-01-01

    Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties.......Widely different metal ion concentrations in blood and serum have been reported with metal-on-metal (MoM) implants. We reviewed the literature on blood and serum ion concentrations of chromium (Cr) and cobalt (Co) following various MoM hip arthroplasties....

  2. Assembling Metal Ions Induced Cyanide-Bridged Heterometallic 1D and Ion-Pair Complexes: Synthesis, Crystal Structures and Magnetic Properties

    International Nuclear Information System (INIS)

    Kong, Lingqian; Zhao, Zengdian; Chen, Kexun; Wang, Ping; Zhang, Daopeng

    2013-01-01

    We obtained a heterobimetallic one-dimensional cyanide-bridged Mn(II)-Ni(II) complex and an Co(III)-Ni(II) ion-pair complex with [Ni(CN) 4 ] 2- as building block and M(II)-phenanthroline (M = Mn, Co) compounds as assembling segment. The different structural types of complexes 1 and 2 indicate that the property of the metal ions the assembling segment contained have obvious influence on the structure of the cyanide-bridged complex. Investigation over the magnetic properties of complex 1 reveals an overall weak antiferromagnetic coupling between the adjacent Mn(II) ions bridged by the antiferromagnetic [-NC-Ni-CN-] unit. Among of all the molecular magnetism systems, for the well known reasons, cyanide-containing complexes have been widely employed as bridges to assemble homo/hetero-metallic molecular magnetic materials by using the cyanide bridge transferring magnetic coupling between the neighboring paramagnetic ions, in whichsome showed interesting magnetic properties, such as high-Tc magnets, spin crossover materials, single-molecule magnets (SMMs) and single-chain magnets (SCMs)

  3. Metal ion separations with proton-ionizable Lariat Ethers and their polymers

    International Nuclear Information System (INIS)

    Bartsch, R.A.

    1993-01-01

    The preparation of novel and specific organic complexing agents may lead to the development of new separation systems for aqueous metal ions. Thus the introduction of highly lipophilic oximes led to the current utilization of these compounds as commercial extractants for the hydrometallurgy of nonferrous metals. Crown ethers (macrocyclic polyethers) have been employed in the laboratory-scale solvent extraction of alkali-metal, alkaline-earth, and other metal cations into organic phases. Attachment of side arms to crown ethers gives lariat ethers. The presence of one or more potential coordination sites in the side arm of the lariat ether may produce substantial changes in the selectivity and efficiency of metal ion complexation. It has been demonstrated that concomitant transfer of an aqueous phase anion into the organic medium is not required for metal ion extraction. This factor is of immense importance to potential practical applications of these proton-ionizable crown ethers in which the common, hard, aqueous phase anions would be involved. Another advantage of proton-ionizable lariat ethers is the ease with which extracted metal ions may be stripped from the organic phase by shaking with aqueous mineral acid. Thus both metal ion extraction and stripping are facilitated by pendent proton-ionizable groups. Most of the hazardous metal ion species in the Hanford Site tank wastes are members of the alkali-metal, alkaline-earth, lanthanide, and actinide families. These hard metal ion species prefer association with hard donor atoms, such as oxygens. Therefore, crown and lariat ethers are well-suited for complexation with such metal ion species

  4. A new biotechnology for recovering heavy metal ions from wastewater

    International Nuclear Information System (INIS)

    Darnall, D.W.; Gabel, A.

    1989-01-01

    This paper reports that bio-recovery systems has developed a new sorption process for removing toxic metal ions from water. This process is based upon the natural, very strong affinity for biological materials, such as the cell walls of plants and microorganisms, for heavy metal ions such as uranium, cadmium, cobalt, nickel, etc.. Biological materials, primarily algae, have been immobilized in a polymer to produce a biological ion exchange resin, AlgaSORB. The material has a remarkable affinity for heavy metal ions and is capable of concentrating these ions by a factor of may thousand-fold. Additionally, the bound metals can be stripped and recovered from the algal material in a manner similar to conventional resins

  5. Production of intense metallic ion beams in order of isotopic separations

    International Nuclear Information System (INIS)

    Sarrouy, J.L.

    1955-01-01

    We describe an isotope separator with magnetic sector of 60 deg that permits, with a process of neutralization of the space charge, to use efficiently intense ion beams. The sources of realized ions provide ionic debits of 10 mA. This present work deals who to obtain intense ion beams (10 to 15 mA), different processes of ion currents measurement, as well as the study of the phenomenon of space charge neutralization. The second part of this memory will be on the survey and the adaptation on the source of various type of oven permitting to spray and to ionize metals directly. By order of increasing difficulty of vaporization, we reached the chromium. (M.B.) [fr

  6. Complexation-induced supramolecular assembly drives metal-ion extraction.

    Science.gov (United States)

    Ellis, Ross J; Meridiano, Yannick; Muller, Julie; Berthon, Laurence; Guilbaud, Philippe; Zorz, Nicole; Antonio, Mark R; Demars, Thomas; Zemb, Thomas

    2014-09-26

    Combining experiment with theory reveals the role of self-assembly and complexation in metal-ion transfer through the water-oil interface. The coordinating metal salt Eu(NO3)3 was extracted from water into oil by a lipophilic neutral amphiphile. Molecular dynamics simulations were coupled to experimental spectroscopic and X-ray scattering techniques to investigate how local coordination interactions between the metal ion and ligands in the organic phase combine with long-range interactions to produce spontaneous changes in the solvent microstructure. Extraction of the Eu(3+)-3(NO3(-)) ion pairs involves incorporation of the "hard" metal complex into the core of "soft" aggregates. This seeds the formation of reverse micelles that draw the water and "free" amphiphile into nanoscale hydrophilic domains. The reverse micelles interact through attractive van der Waals interactions and coalesce into rod-shaped polynuclear Eu(III) -containing aggregates with metal centers bridged by nitrate. These preorganized hydrophilic domains, containing high densities of O-donor ligands and anions, provide improved Eu(III) solvation environments that help drive interfacial transfer, as is reflected by the increasing Eu(III) partitioning ratios (oil/aqueous) despite the organic phase approaching saturation. For the first time, this multiscale approach links metal-ion coordination with nanoscale structure to reveal the free-energy balance that drives the phase transfer of neutral metal salts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Metal ion sequestration: An exciting dimension for molecularly ...

    African Journals Online (AJOL)

    The use of a tight binding macrocyclic ligand to complex a metal ion so that this serves as receptee on the Molecularly Imprinted Polymer (MIP) receptor as described here affords a sequestration route for a targeted metal ion, with potential for environmental remediation and restoration applications. Ethylene glycol ...

  8. Complexation ion-exchange chromatography of some metal ions on papers impregnated with Ti(IV)-based inorganic ion exchangers.

    Science.gov (United States)

    Sharma, S D; Gupta, R

    2000-02-01

    The chromatographic behavior of 40 metal ions is studied on titanium (IV) arsenate, titanium (IV) phosphate-, titanium (IV) molybdate-, titanium(IV) tungstate-, and titanium(IV) selenite-impregnated papers in 0.1M oxalic, citric, and tartaric acid as mobile phases. Similar studies are carried out on Whatman No. 1 papers for comparison. The ion-exchange capacity of these papers is determined, and their selectivity for different cations is discussed. The mechanism of migration is explained in terms of ion-exchange, precipitation, and adsorption. The prediction of elution sequence from RF values is also checked. The average Ri is found to be almost linearly dependent on the charge of the metal ions. The effect of the pKa of complexing acids on average RF values of 3d series metal ions is explained. A number of binary and ternary separations are achieved.

  9. Improving Passivation Process of Si Nano crystals Embedded in SiO2 Using Metal Ion Implantation

    International Nuclear Information System (INIS)

    Bornacelli, J.; Esqueda, J.A.R.; Fernandez, L.R.; Oliver, A.

    2013-01-01

    We studied the photoluminescence (PL) of Si nano crystals (Si-NCs) embedded in SiO 2 obtained by ion implantation at MeV energy. The Si-NCs are formed at high depth (1-2 μm) inside the SiO 2 achieving a robust and better protected system. After metal ion implantation (Ag or Au), and a subsequent thermal annealing at 600°C under hydrogen-containing atmosphere, the PL signal exhibits a noticeable increase. The ion metal implantation was done at energies such that its distribution inside the silica does not overlap with the previously implanted Si ion . Under proper annealing Ag or Au nanoparticles (NPs) could be nucleated, and the PL signal from Si-NCs could increase due to plasmonic interactions. However, the ion-metal-implantation-induced damage can enhance the amount of hydrogen, or nitrogen, that diffuses into the SiO 2 matrix. As a result, the surface defects on Si-NCs can be better passivated, and consequently, the PL of the system is intensified. We have selected different atmospheres (air, H 2 /N 2 and Ar) to study the relevance of these annealing gases on the final PL from Si-NCs after metal ion implantation. Studies of PL and time-resolved PL indicate that passivation process of surface defects on Si-NCs is more effective when it is assisted by ion metal implantation.

  10. Adsorption of Heavy Metal Ions from Aqueous Solutions by Bentonite Nanocomposites.

    Science.gov (United States)

    Ma, Jing; Su, Guojun; Zhang, Xueping; Huang, Wen

    2016-08-01

    A series of bentonite nanocomposites have been synthesized by modifying bentonite with hexadecyltrimethylammonium bromide (CTMAB) and the common complexing agents, complexone (ethylene diamine tetraacetic acid, EDTA) or mercaptocomplexant (2-Mercaptobenzothiazole, MBT). These adsorbents are used to remove heavy metal ions (Cu(2+), Zn(2+), Mn(2+),Co(2+)). The Bent-CTMAB-MBT adsorbed metal ions are higher than Bent-CTMAB-EDTA under the same ion concentration in AAS. Compared with the single ion system, the adsorption of the mixed ion system of Cu(2+), Zn(2+), Mn(2+), Co(2+) had decreased differently. In the mixed system, the adsorption of Mn(2+) is significantly lower, but the adsorption of Cu(2+) was highest. The adsorption sequence of these four metal ions was Cu(2+) > Zn(2+) > Co(2+) > Mn(2+), and the selective adsorption was closely related to the hydration energy of heavy metal ions. We could remove more metal ions in different stages with the adsorption sequence.

  11. 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. 2010 Elsevier B.V. All rights reserved.

  12. Bioavailability of Metal Ions and Evolutionary Adaptation

    Directory of Open Access Journals (Sweden)

    Rolando P. Hong Enriquez

    2012-10-01

    Full Text Available The evolution of life on earth has been a long process that began nearly 3,5 x 109 years ago. In their initial moments, evolution was mainly influenced by anaerobic environments; with the rise of O2 and the corresponding change in bioavailability of metal ions, new mechanisms of survival were created. Here we review the relationships between ancient atmospheric conditions, metal ion bioavailability and adaptation of metals homeostasis during early evolution. A general picture linking geochemistry, biochemistry and homeostasis is supported by the reviewed literature and is further illustrated in this report using simple database searches.

  13. Chromatography Of Metal Ions On Wood Cellulose Impregnated ...

    African Journals Online (AJOL)

    Adsorption chromatography of some heavy metal ions on wood cellulose of saw dust (wood waste dust) modified with hydrochloric acid, urea and thiourea was studied. Atomic absorption spectrophotometry (AAS) was used to determine the initial concentration of solutions of Zn2+, Cu2+, Ni2+, Pb2+, and Fe3+ metal ions.

  14. Metal hydride compositions and lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Young, Kwo; Nei, Jean

    2018-04-24

    Heterogeneous metal hydride (MH) compositions comprising a main region comprising a first metal hydride and a secondary region comprising one or more additional components selected from the group consisting of second metal hydrides, metals, metal alloys and further metal compounds are suitable as anode materials for lithium ion cells. The first metal hydride is for example MgH.sub.2. Methods for preparing the composition include coating, mechanical grinding, sintering, heat treatment and quenching techniques.

  15. Synthesis and characterisation of 8-hydroxyquinoline-bovine serum albumin conjugates as metal ion chelating proteins

    International Nuclear Information System (INIS)

    Giraudi, G.; Baggiani, C.; Giovannoli, C.; Marletto, C.; Vanni, A.

    1999-01-01

    A derivative of 8-hydroxyquinoline (8-quinolinol, oxine) with a linking bridge containing a carboxylic group was covalently coupled to bovine serum albumin by the N-hydroxysuccinimide method to obtain stable monomeric conjugates with oxine to protein mole ratios up to 37. These conjugates were characterised spectrophotometrically and their complexation properties were confirmed by spectral analysis with and without the addition of Al(III), Cd(II), Co(II), Cu(II), Hg(II), Mn(II), Ni(II), Pb(II), V(IV), U(VI) and Zn(II) ions added. The maximum number of ions bound by these chelating proteins was determined spectrophotometrically by titration with metal ions at pH 6.0. The conjugates with a substitution ratio (moles of 8-hydroxyquinoline bound/mole of albumin) less than about 8 showed 1:1 binding with metal ions, while conjugates with higher substitution ratios were able to complex with 2:1 ratio of 8-hydroxyquinoline to metal ion. Association and dissociation kinetics of complexation with copper(II) ions showed a complex mechanism. The spectral and binding properties of these metal ion-binding proteins confirm that the coupling of the 8-hydroxyquinoline derivative to bovine serum albumin gives stable, water soluble, macromolecular chelating agents that retain the complexing ability of the original ligand. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  16. Metal oxide collectors for storing matter technique applied in secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Miśnik, Maciej [Institute of Tele and Radio Technology, ul. Ratuszowa 11, 03-450 Warszawa (Poland); Gdańsk University of Technology (Poland); Konarski, Piotr [Institute of Tele and Radio Technology, ul. Ratuszowa 11, 03-450 Warszawa (Poland); Zawada, Aleksander [Institute of Tele and Radio Technology, ul. Ratuszowa 11, 03-450 Warszawa (Poland); Military University of Technology, Warszawa (Poland)

    2016-03-15

    We present results of the use of metal and metal oxide substrates that serve as collectors in ‘storing matter’, the quantitative technique of secondary ion mass spectrometry (SIMS). This technique allows separating the two base processes of secondary ion formation in SIMS. Namely, the process of ion sputtering is separated from the process of ionisation. The technique allows sputtering of the analysed sample and storing the sputtered material, with sub-monolayer coverage, onto a collector surface. Such deposits can be then analysed by SIMS, and as a result, the so called ‘matrix effects’ are significantly reduced. We perform deposition of the sputtered material onto Ti and Cu substrates and also onto metal oxide substrates as molybdenum, titanium, tin and indium oxides. The process of sputtering is carried within the same vacuum chamber where the SIMS analysis of the collected material is performed. For sputtering and SIMS analysis of the deposited material we use 5 keV Ar{sup +} beam of 500 nA. The presented results are obtained with the use of stationary collectors. Here we present a case study of chromium. The obtained results show that the molybdenum and titanium oxide substrates used as collectors increase useful yield by two orders, with respect to such pure elemental collectors as Cu and Ti. Here we define useful yield as a ratio of the number of detected secondary ions during SIMS analysis and the number of atoms sputtered during the deposition process.

  17. Application of ion implantation in metals and alloys

    International Nuclear Information System (INIS)

    Dearnaley, G.

    1981-01-01

    Ion implantation first became established as a precise method of introducing dopant elements into semiconductors. It is now appreciated that there may be equally important applications in metallic tools or components with the purpose of improving their resistance to wear, fatigue or corrosion. Nitrogen ions implanted into steels pin dislocations and thereby harden the metal. Some metallic ions such as yttrium reduce the tendency for oxidative wear. There is a fairly good understanding of how both treatments can provide a long-lasting protection that extends to many times the original depth of implantation. Nitrogen implantation also improves the wear resistance of Co-cemented tungsten carbide and of hard chromium electroplated coatings. These treatments have wide application in press tools, molds, dies and other metal-forming tools as well as in a more limited variety of cutting tools. Some striking improvements can be achieved in the corrosion field, but there are economic and technical reasons for concluding that practical applications of ion implantation will be more restricted and specialized in this area. The most promising area is that in which mechanical stress and oxidation coexist. When a metallic species has to be introduced, a promising new development is to bombard a thin coating of the metal at an elevated temperature. Several powerful mechanisms of radiation-enhanced diffusion can bring about a complete intermixing. Examples of how this has been used to produce wear resistant surfaces in titanium are given. Finally, the equipment developed for the large scale application of the ion implantation process in the engineering field is described

  18. Progress in metal ion separation and preconcentration: an overview

    International Nuclear Information System (INIS)

    Bond, A. H.

    1998-01-01

    A brief historical perspective covering the most mature chemically-based metal ion separation methods is presented, as is a summary of the recommendations made in the 1987 National Research Council (NRC) report entitled ''Separation and Purification: Critical Needs and Opportunities''. A review of Progress in Metal Ion Separation and Preconcentration shows that advances are occurring in each area of need cited by the NRC. Following an explanation of the objectives and general organization of this book, the contents of each chapter are briefly summarized and some future research opportunities in metal ion separations are presented

  19. Effect of organic acids produced by penicillium notatum on the extraction of metals ions from brown shale

    International Nuclear Information System (INIS)

    Bhatti, H.N.; Sarwar, S.; Ilyas, S.

    2012-01-01

    Preset study was undertaken to check the bio leaching feasibility of brown shale with Penicillium notatum by using different carbon sources. Large quantities of the metal ions are embodied in shales that can be recovered. Presently available techniques (pyrometallurgical and hydrometallurgical) are expensive or may have a negative impact on the environment. Penicillium notatum exhibited a good potential in generating varieties of organic acids effective for metal ions solubilization. Maximum leaching of Cu (91.55 %) and Mg (79.83 %) was obtained with glucose as substrate while maximum recovery of Mn (71.46 %) was obtained in medium having molasses as substrate. (author)

  20. Electrospray Ionization Mass Spectrometry: From Cluster Ions to Toxic metal Ions in Biology

    Energy Technology Data Exchange (ETDEWEB)

    Lentz, Nicholas B. [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    This dissertation focused on using electrospray ionization mass spectrometry to study cluster ions and toxic metal ions in biology. In Chapter 2, it was shown that primary, secondary and quarternary amines exhibit different clustering characteristics under identical instrument conditions. Carbon chain length also played a role in cluster ion formation. In Chapters 3 and 4, the effects of solvent types/ratios and various instrumental parameters on cluster ion formation were examined. It was found that instrument interface design also plays a critical role in the cluster ion distribution seen in the mass spectrum. In Chapter 5, ESI-MS was used to investigate toxic metal binding to the [Gln11]-amyloid β-protein fragment (1-16). Pb and Cd bound stronger than Zn, even in the presence of excess Zn. Hg bound weaker than Zn. There are endless options for future work on cluster ions. Any molecule that is poorly ionized in positive ion mode can potentially show an increase in ionization efficiency if an appropriate anion is used to produce a net negative charge. It is possible that drug protein or drug/DNA complexes can also be stabilized by adding counter-ions. This would preserve the solution characteristics of the complex in the gas phase. Once in the gas phase, CID could determine the drug binding location on the biomolecule. There are many research projects regarding toxic metals in biology that have yet to be investigated or even discovered. This is an area of research with an almost endless future because of the changing dynamics of biological systems. What is deemed safe today may show toxic effects in the future. Evolutionary changes in protein structures may render them more susceptible to toxic metal binding. As the understanding of toxicity evolves, so does the demand for new toxic metal research. New instrumentation designs and software make it possible to perform research that could not be done in the past. What was undetectable yesterday will

  1. Ion beam induced nanosized Ag metal clusters in glass

    International Nuclear Information System (INIS)

    Mahnke, H.-E.; Schattat, B.; Schubert-Bischoff, P.; Novakovic, N.

    2006-01-01

    Silver metal clusters have been formed in soda lime glass by high-energy heavy-ion irradiation at ISL. The metal cluster formation was detected with X-ray absorption spectroscopy (EXAFS) in fluorescence mode, and the shape of the clusters was imaged with transmission electron microscopy. While annealing in reducing atmosphere alone, leads to the formation of metal clusters in Ag-containing glasses, where the Ag was introduced by ion-exchange, such clusters are not very uniform in size and are randomly distributed over the Ag-containing glass volume. Irradiation with 600-MeV Au ions followed by annealing, however, results in clusters more uniform in size and arranged in chains parallel to the direction of the ion beam

  2. Fluorescence signalling of the transition metal ions: Design strategy ...

    Indian Academy of Sciences (India)

    Unknown

    strategy based on the choice of the fluorophore component. N B SANKARAN, S ... skill for the development of fluorosensors of this kind. Further, the ... salts of the transition metal ions have been used for studying the influence of the metal ions.

  3. Metal ion concentrations in body fluids after implantation of hip replacements with metal-on-metal bearing--systematic review of clinical and epidemiological studies.

    Directory of Open Access Journals (Sweden)

    Albrecht Hartmann

    Full Text Available INTRODUCTION: The use of metal-on-metal (MoM total hip arthroplasty (THA increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. OBJECTIVE: To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. METHODS: Systematic review of clinical trials (RCTs and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor, patient characteristics as well as study quality characteristics (secondary explanatory factors. RESULTS: Overall, 104 studies (11 RCTs, 93 epidemiological studies totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L. Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. DISCUSSION: Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed "time out" for stemmed large-head MoM-THA and recommend a restricted

  4. Sulfide precipitation method of separating uranium from Group II and Group III metal ions

    International Nuclear Information System (INIS)

    Sundar, P.S.

    1977-01-01

    Uranium is separated from analytical Group II and Group III metal ions in an aqueous liquor containing uranyl ions. The liquor is extracted with a non-interfering, water-immiscible, organic solvent containing a reagent which will react with the uranyl ions to form a complex soluble in the solvent. If the liquor is acidic, the solvent is washed with water. Then to the solvent is added an aqueous solution containing about 0.5 to 1.0 mole per liter of (NH 4 ) 2 CO 3 or NH 4 HCO 3 ions and sufficient sulfide ions to precipitate the metal ions as sulfides. The solvent and the aqueous solution are separated and the sulfides filtered from the aqueous solution. The ammonium-uranyl-tricarbonate in the aqueous solution can then be precipitated by increasing the concentration of (NH 4 ) 2 CO 3 or NH 4 HCO 3 ions to about 1.5 to 2.5 moles per liter. The precipitate is filtered and calcined to obtain U 3 O 8 or UO 2 . 21 claims, 1 figure

  5. Modification of metallic corrosion by ion implantation

    International Nuclear Information System (INIS)

    Clayton, C.R.

    1981-01-01

    This review will consider some of the properties of surface alloys, formed by ion implantation, which are effective in modifying corrosion behaviour. Examples will be given of the modification of the corrosion behaviour of pure metals, steels and other engineering alloys, resulting from implantation with metals and metalloids. Emphasis will be given to the modification of anodic processes produced by ion implantation since a review will be given elsewhere in the proceedings concerning the modification of cathodic processes. (orig.)

  6. High dose, heavy ion implantation into metals: the use of sacrificial surface layers to enhance retention

    International Nuclear Information System (INIS)

    Clapham, L.

    1994-01-01

    While of considerable interest for the production of metallic alloys, high dose, heavy ion implantation is highly problematical, since the process is limited by sputtering effects. Sputtering is less significant, however, for light target materials, such as C and Al. This paper summarizes studies involving the use of light materials (such as C and Al) which act as slowly sputtering ''sacrificial layers'' when deposited on metallic targets prior to heavy ion implantation. The use of C and Al sacrificial coatings has enabled implanted ion retentions of 100% to be obtained in a number of ion-metal target systems, where the retentions in uncoated samples were as low as 20%. Ion implantation invariably leads to mixing at the sacrificial layer-metal target interface. This mixing may be detrimental in certain systems, so it is useful to be able to minimize or remove this mixed region. To achieve this, a number of techniques have been investigated: (1) removal of the mixed region in the latter stages of the implant; (2) using a barrier layer or chemical effects to minimize mixing at the sacrificial layer-metal interface; (3) choosing a sacrificial layer material which forms a mixed region which has desirable properties. The results of these investigations, for a number of different ion-target systems, are outlined in this paper. (orig.)

  7. Adsorption preference for divalent metal ions by Lactobacillus casei JCM1134.

    Science.gov (United States)

    Endo, Rin; Aoyagi, Hideki

    2018-05-09

    The removal of harmful metals from the intestinal environment can be inhibited by various ions which can interfere with the adsorption of target metal ions. Therefore, it is important to understand the ion selectivity and adsorption mechanism of the adsorbent. In this study, we estimated the adsorption properties of Lactobacillus casei JCM1134 by analyzing the correlation between its maximum adsorption level (q max ) for seven metals and their ion characteristics. Some metal ions showed altered adsorption levels by L. casei JCM1134 as culture growth time increased. Although it was impossible to identify specific adsorption components, adsorption of Sr and Ba may depend on capsular polysaccharide levels. The maximum adsorption of L. casei JCM1134 (9 h of growth in culture) for divalent metal ions was in the following order: Cu 2+  > Ba 2+  > Sr 2+  > Cd 2+  > Co 2+  > Mg 2+  > Ni 2+ . The q max showed a high positive correlation with the ionic radius. Because this tendency is similar to adsorption occurring through an ion exchange mechanism, it was inferred that an ion exchange mechanism contributed greatly to adsorption by L. casei JCM1134. Because the decrease in the amount of adsorption due to prolonged culture time was remarkable for metals with a large ion radius, it is likely that the adsorption components involved in the ion exchange mechanism decomposed over time. These results and analytical concept may be helpful for designing means to remove harmful metals from the intestinal tract.

  8. Surface modification of metals by ion implantation

    International Nuclear Information System (INIS)

    Iwaki, Masaya

    1988-01-01

    Ion implantation in metals has attracted the attention as a useful technology for the formation of new metastable alloys and compounds in metal surface layers without thermal equilibrium. Current studies of metal surface modification by ion implantation with high fluences have expanded from basic research areas and to industrial applications for the improvement of life time of tools. Many results suggest that the high fluence implantation produces the new surface layers with un-expected microscopic characteristics and macroscopic properties due to implant particles, radiation damage, sputtering, and knock-on doping. In this report, the composition, structure and chemical bonding state in surface layers of iron, iron-based alloy and aluminum sheets implanted with high fluences have been investigated by means of secondary ion mass spectroscopy (SIMS), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Tribological properties such as hardness, friction and wear are introduced. (author)

  9. Very broad beam metal ion source for large area ion implantation application

    International Nuclear Information System (INIS)

    Brown, I.; Anders, S.; Dickinson, M.R.; MacGill, R.A.; Yao, X.

    1993-01-01

    The authors have made and operated a very broad beam version of vacuum arc ion source and used it to carry out high energy metal ion implantation of a particularly large substrate. A multiple-cathode vacuum arc plasma source was coupled to a 50 cm diameter beam extractor (multiple aperture, accel-decel configuration) operated at a net extraction voltage of up to 50 kV. The metal ion species chosen were Ni and Ta. The mean ion charge state for Ni and Ta vacuum arc plasmas is 1.8 and 2.9, respectively, and so the mean ion energies were up to about 90 and 145 keV, respectively. The ion source was operated in a repetitively pulsed mode with pulse length 250 μs and repetition rate several pulses per second. The extracted beam had a gaussian profile with FWHM about 35 cm, giving a nominal beam area of about 1,000 cm 2 . The current of Ni or Ta metal ions in the beam was up to several amperes. The targets for the ion implantation were a number of 24-inch long, highly polished Cu rails from an electromagnetic rail gun. The rails were located about 80 cm away from the ion source extractor grids, and were moved across a diameter of the vessel in such a way as to maximize the uniformity of the implant along the rail. The saturation retained dose for Ta was limited to about 4 x 10 16 cm -2 because of the rather severe sputtering, in accordance with the theoretical expectations for these implantation conditions. Here they describe the ion source, the implantation procedure, and the kinds of implants that can be produced in this way

  10. Assembling Metal Ions Induced Cyanide-Bridged Heterometallic 1D and Ion-Pair Complexes: Synthesis, Crystal Structures and Magnetic Properties

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Lingqian [Liaocheng Univ., Liaocheng (China); Zhao, Zengdian; Chen, Kexun; Wang, Ping; Zhang, Daopeng [Shandong Univ. of Technology, Zibo (China)

    2013-07-15

    We obtained a heterobimetallic one-dimensional cyanide-bridged Mn(II)-Ni(II) complex and an Co(III)-Ni(II) ion-pair complex with [Ni(CN){sub 4}]{sup 2-} as building block and M(II)-phenanthroline (M = Mn, Co) compounds as assembling segment. The different structural types of complexes 1 and 2 indicate that the property of the metal ions the assembling segment contained have obvious influence on the structure of the cyanide-bridged complex. Investigation over the magnetic properties of complex 1 reveals an overall weak antiferromagnetic coupling between the adjacent Mn(II) ions bridged by the antiferromagnetic [-NC-Ni-CN-] unit. Among of all the molecular magnetism systems, for the well known reasons, cyanide-containing complexes have been widely employed as bridges to assemble homo/hetero-metallic molecular magnetic materials by using the cyanide bridge transferring magnetic coupling between the neighboring paramagnetic ions, in whichsome showed interesting magnetic properties, such as high-Tc magnets, spin crossover materials, single-molecule magnets (SMMs) and single-chain magnets (SCMs)

  11. Broad-beam, high current, metal ion implantation facility

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

    1990-07-01

    We have developed a high current metal ion implantation facility with which high current beams of virtually all the solid metals of the Periodic Table can be produced. The facility makes use of a metal vapor vacuum arc ion source which is operated in a pulsed mode, with pulse width 0.25 ms and repetition rate up to 100 pps. Beam extraction voltage is up to 100 kV, corresponding to an ion energy of up to several hundred keV because of the ion charge state multiplicity; beam current is up to several Amperes peak and around 10 mA time averaged delivered onto target. Implantation is done in a broad-beam mode, with a direct line-of-sight from ion source to target. Here we describe the facility and some of the implants that have been carried out using it, including the 'seeding' of silicon wafers prior to CVD with titanium, palladium or tungsten, the formation of buried iridium silicide layers, and actinide (uranium and thorium) doping of III-V compounds. 16 refs., 6 figs

  12. Progress in metal ion separation and preconcentration : an overview.

    Energy Technology Data Exchange (ETDEWEB)

    Bond, A. H.

    1998-05-19

    A brief historical perspective covering the most mature chemically-based metal ion separation methods is presented, as is a summary of the recommendations made in the 1987 National Research Council (NRC) report entitled ''Separation and Purification: Critical Needs and Opportunities''. A review of Progress in Metal Ion Separation and Preconcentration shows that advances are occurring in each area of need cited by the NRC. Following an explanation of the objectives and general organization of this book, the contents of each chapter are briefly summarized and some future research opportunities in metal ion separations are presented.

  13. Heavy metal ion adsorption onto polypyrrole-impregnated porous carbon.

    Science.gov (United States)

    Choi, Moonjung; Jang, Jyongsik

    2008-09-01

    Polypyrrole-impregnated porous carbon was readily synthesized using vapor infiltration polymerization of pyrrole monomers. The results show that the functionalized polymer layer was successfully coated onto the pore surface of carbon without collapse of mesoporous structure. The modified porous carbon exhibited an improved complexation affinity for heavy metal ions such as mercury, lead, and silver ions due to the amine group of polypyrrole. The introduced polypyrrole layer could provide the surface modification to be applied for heavy metal ion adsorbents. Especially, polymer-impregnated porous carbon has an enhanced heavy metal ion uptake, which is 20 times higher than that of adsorbents with amine functional groups. Furthermore, the relationship between the coated polymer amount and surface area was also investigated in regard to adsorption capacity.

  14. Heavy metal ions are potent inhibitors of protein folding

    International Nuclear Information System (INIS)

    Sharma, Sandeep K.; Goloubinoff, Pierre; Christen, Philipp

    2008-01-01

    Environmental and occupational exposure to heavy metals such as cadmium, mercury and lead results in severe health hazards including prenatal and developmental defects. The deleterious effects of heavy metal ions have hitherto been attributed to their interactions with specific, particularly susceptible native proteins. Here, we report an as yet undescribed mode of heavy metal toxicity. Cd 2+ , Hg 2+ and Pb 2+ proved to inhibit very efficiently the spontaneous refolding of chemically denatured proteins by forming high-affinity multidentate complexes with thiol and other functional groups (IC 50 in the nanomolar range). With similar efficacy, the heavy metal ions inhibited the chaperone-assisted refolding of chemically denatured and heat-denatured proteins. Thus, the toxic effects of heavy metal ions may result as well from their interaction with the more readily accessible functional groups of proteins in nascent and other non-native form. The toxic scope of heavy metals seems to be substantially larger than assumed so far

  15. Highly sensitive colour change system within slight differences in metal ion concentrations based on homo-binuclear complex formation equilibrium for visual threshold detection of trace metal ions

    International Nuclear Information System (INIS)

    Mizuguchi, Hitoshi; Atsumi, Hiroshi; Hashimoto, Keigo; Shimada, Yasuhiro; Kudo, Yuki; Endo, Masatoshi; Yokota, Fumihiko; Shida, Junichi; Yotsuyanagi, Takao

    2004-01-01

    A new technique of expressing slight differences in metal ion concentrations by clear difference in colour was established for visual threshold detection of trace metal ions. The proposed method is based on rapid change of the mole fraction of the homo-binuclear complex (M 2 L) about a ligand in a narrow range of the total metal ion concentration (M T ) in a small excess, in case the second metal ion is bound to the reagent molecule which can bind two metal ions. Theoretical simulations showed that the highly sensitive colour change within slight differences in metal ion concentrations would be realized under the following conditions: (i) both of the stepwise formation constants of complex species are sufficiently large; (ii) the stepwise formation constant of the 1:1 complex (ML) is larger than that of M 2 L; and (iii) the absorption spectrum of M 2 L is far apart from the other species in the visible region. Furthermore, the boundary of the colour region in M T would be readily controlled by the total ligand concentration (L T ). Based on this theory, the proposed model was verified with the 3,3'-bis[bis(carboxymethyl)amino]methyl derivatives of sulphonephthalein dyes such as xylenol orange (XO), methylthymol blue (MTB), and methylxylenol blue (MXB), which can bind two metal ions at both ends of a π-electron conjugated system. The above-mentioned model was proved with the iron(III)-XO system at pH 2. In addition, MTB and MXB were suitable reagents for the visual threshold detection of trivalent metal ions such as iron(III), aluminium(III), gallium(III) and indium(III) ion in slightly acidic media. The proposed method has been applied successfully as a screening test for aluminium(III) ion in river water sampled at the downstream area of an old mine

  16. Metal ion transport quantified by ICP-MS in intact cells

    Science.gov (United States)

    Figueroa, Julio A. Landero; Stiner, Cory A.; Radzyukevich, Tatiana L.; Heiny, Judith A.

    2016-01-01

    The use of ICP-MS to measure metal ion content in biological tissues offers a highly sensitive means to study metal-dependent physiological processes. Here we describe the application of ICP-MS to measure membrane transport of Rb and K ions by the Na,K-ATPase in mouse skeletal muscles and human red blood cells. The ICP-MS method provides greater precision and statistical power than possible with conventional tracer flux methods. The method is widely applicable to studies of other metal ion transporters and metal-dependent processes in a range of cell types and conditions. PMID:26838181

  17. Effect of metal ion concentration on the biosorption of Pb2+ and ...

    African Journals Online (AJOL)

    The influence of initial metal ion concentration of the batch sorption of Pb2+ and Cd2+ onto a low-cost biosorbent was investigated. The experimental results were analysed in terms of Langmuir and Freundlich isotherms. According to the evaluation using Langmuir equation, the monolayer sorption capacity obtained were ...

  18. Ion beam assisted deposition of metal-coatings on beryllium

    International Nuclear Information System (INIS)

    Tashlykov, I.S.; Tul'ev, V.V.

    2015-01-01

    Thin films were applied on beryllium substrates on the basis of metals (Cr, Ti, Cu and W) with method of the ion-assisted deposition in vacuum. Me/Be structures were prepared using 20 kV ions irradiation during deposition on beryllium neutral fraction generated from vacuum arc plasma. Rutherford back scattering and computer simulation RUMP code were applied to investigate the composition of the modified beryllium surface. Researches showed that the superficial structure is formed on beryllium by thickness ~ 50-60 nm. The covering composition includes atoms of the deposited metal (0.5-3.3 at. %), atoms of technological impurity carbon (0.8-1.8 at. %) and oxygen (6.3-9.9 at. %), atoms of beryllium from the substrate. Ion assisted deposition of metals on beryllium substrate is accompanied by radiation enhanced diffusion of metals, oxygen atoms in the substrate, out diffusion of beryllium, carbon atoms in the deposited coating and sputtering film-forming ions assists. (authors)

  19. Hydrolysis of metal ions. Vol. 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Paul L. [Geochem Australia, Kiama, NSW (Australia); Ekberg, Christian [Chalmers Univ. of Technology, Goeteborg (Sweden). Nuclear Chemistry/Industrial Materials Recycling

    2016-07-01

    Filling the need for a comprehensive treatment that covers the theory, methods and the different types of metal ion complexes with water (hydrolysis), this handbook and ready reference is authored by a nuclear chemist from academia and an industrial geochemist. The book includes both cation and anion complexes, and approaches the topic of metal ion hydrolysis by first covering the background, before proceeding with an overview of the dissociation of water and then all different metal-water hydrolysis complexes and compounds. A must-have for scientists in academia and industry working on this interdisciplinary topic.

  20. Charge state of ions scattered by metal surface

    International Nuclear Information System (INIS)

    Kishinevsky, L.M.; Parilis, E.S.; Verleger, V.K.

    1976-01-01

    A model for description of charge distributions for scattering of heavy ions in the keV region, on metal surfaces developing and improving the method of Van der Weg and Bierman, and taking into account the connection between the ion charge state and scattering kinematics, is proposed. It is shown that multiple charged particles come from ions with a vacancy in the inner shell while the outer shell vacancies give only single charged ions and neutrals. The approximately linear increase of degree of ionization with normal velocity, and the non-monotonic charge dependence of the energy spectrum established by Chicherov and Buck et al is explained by considering irreversible neutralization in the depth of the metal, taking into account the connection of the charge state with the shape of trajectory and its location relative to the metal surface. The dependence of charge state on surface structure is discussed. Some new experiments are proposed. (author)

  1. Adhesive, abrasive and oxidative wear in ion-implanted metals

    International Nuclear Information System (INIS)

    Dearnaley, G.

    1985-01-01

    Ion implantation is increasingly being used to provide wear resistance in metals and cemented tungsten carbides. Field trials and laboratory tests indicate that the best performance is achieved in mild abrasive wear. This can be understood in terms of the classification of wear modes (adhesive, abrasive, oxidative etc.) introduced by Burwell. Surface hardening and work hardenability are the major properties to be enhanced by ion implantation. The implantation of nitrogen or dual implants of metallic and interstitial species are effective. Recently developed techniques of ion-beam-enhanced deposition of coatings can further improve wear resistance by lessening adhesion and oxidation. In order to support such hard coatings, ion implantation of nitrogen can be used as a preliminary treatment. There is thus emerging a versatile group of related hard vacuum treatments involving intense beams of nitrogen ions for the purpose of tailoring metal surfaces to resist wear. (Auth.)

  2. Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing – Systematic Review of Clinical and Epidemiological Studies

    Science.gov (United States)

    Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

    2013-01-01

    Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip

  3. The adsorption kinetics of metal ions onto different microalgae and siliceous earth.

    Science.gov (United States)

    Schmitt, D; Müller, A; Csögör, Z; Frimmel, F H; Posten, C

    2001-03-01

    In the present work the adsorption kinetics of the six metal ions aluminum, zinc, mercury, lead, copper, and cadmium onto living microalgae were measured. The freshwater green microalga Scenedesmus subspicatus, the brackish water diatom Cyclotella cryptica, the seawater diatom Phaeodactylum tricornutum, and the seawater red alga Porphyridium purpureum were the subject of investigation. In most cases the adsorption rate of the metals could be well described by using the equation of the Langmuir adsorption rate expression. Inverse parameter estimation allowed the determination of the rate constants of the adsorption process and the maximum metal content of the algae. The highest values for the rate constant were obtained for Porphyridium purpureum followed by Phaeodactylum tricornutum. High values for the maximum content were obtained for Cyclotella cryptica and Scenedesmus subspicatus. The maximum rate constant was 24.21 h-1 for the adsorption of Hg to Porphyridium purpureum whereas the maximum metal content (0.243 g g-1) was obtained for Zn on Cyclotella cryptica. A comparison of these values with those obtained for the mineral siliceous earth exhibiting low maximum content and high adsorption rates reveals that the mechanism of adsorption onto the algae is a mixture of adsorption and accumulation.

  4. Solution thermodynamics of rare-earth metal ions - physicochemical study-

    Energy Technology Data Exchange (ETDEWEB)

    Amerkhanova, Sh K; Shlyapov, R M; Uali, A S [Buketov Karaganda state university, University str., 28, Karaganda, 100028 (Kazakhstan)], E-mail: amerkhanova_sh@mail.ru

    2009-02-01

    The results of the studying of interactions in multicomponent systems 'polyvinyl alcohol (PVA) - rare-earth element ion - nitrate of sodium - water' are represented. It is established that for rubidium (I) ions temperature and ionic strength is render destroying action, and for yttrium (III) ions the influence of these factors has return character which is connected with features of an electronic structure of metal ion. It is revealed that a dominating role of non-electrostatic formation composed, hence, the formation of donor-acceptor connection of 'metal - ligand' occurs through atom of oxygen.

  5. Accumulation of some metal ions on Bacillus licheniformis

    International Nuclear Information System (INIS)

    Hafez, M.B.; El-Desouky, W.; Fouad, A.

    2001-01-01

    Pure species of Bacillus licheniformis was used to remove ions from aqueous and simulated waste solutions. Metal ion accumulation on B. licheniformis was fast. Maximum uptake occurred at pH 4± 0.5 and at 25 ± 3 deg C. One gram of dry B. licheniformis was found to accumulate 115 mg cerium, 34 mg copper and 11 mg cobalt from aqueous solutions. The presence of certain foreign ions such as calcium, sodium and potassium decreased the uptake of ions by B. licheniformis, while citrate and EDTA prevent the uptake. Electron microscopic investigations showed that cerium (III), copper (II) and cobalt (II) accumulated extracellulary around the surface wall of B. licheniformis cells. A bio-adsorption mechanism between the metal ions and B. licheniformis cell wall was proposed. (author)

  6. Ion conducting polymers and polymer blends for alkali metal ion batteries

    Science.gov (United States)

    DeSimone, Joseph M.; Pandya, Ashish; Wong, Dominica; Vitale, Alessandra

    2017-08-29

    Electrolyte compositions for batteries such as lithium ion and lithium air batteries are described. In some embodiments the compositions are liquid compositions comprising (a) a homogeneous solvent system, said solvent system comprising a perfluropolyether (PFPE) and polyethylene oxide (PEO); and (b) an alkali metal salt dissolved in said solvent system. In other embodiments the compositions are solid electrolyte compositions comprising: (a) a solid polymer, said polymer comprising a crosslinked product of a crosslinkable perfluropolyether (PFPE) and a crosslinkable polyethylene oxide (PEO); and (b) an alkali metal ion salt dissolved in said polymer. Batteries containing such compositions as electrolytes are also described.

  7. Applications of ion plating in metals fabrication

    International Nuclear Information System (INIS)

    Bell, R.T.; Thompson, J.C.

    1974-01-01

    Use of ion plating at the Oak Ridge Y-12 Plant to solve problems encountered in metals fabrication and processing are discussed. Three typical areas are covered. The first is the use of strike coats on various substrates for subsequent electrodeposition. The second area in which ion plating is shown to contribute to a process is in cold welding or room temperature bonding of metals. The third application involves plating U to promote safe handling, fission-product retention, and corrosion protection in nuclear reactors

  8. Cooperative adsorption of critical metal ions using archaeal poly-γ-glutamate.

    Science.gov (United States)

    Hakumai, Yuichi; Oike, Shota; Shibata, Yuka; Ashiuchi, Makoto

    2016-06-01

    Antimony, beryllium, chromium, cobalt (Co), gallium (Ga), germanium, indium (In), lithium, niobium, tantalum, the platinoids, the rare-earth elements (including dysprosium, Dy), and tungsten are generally regarded to be critical (rare) metals, and the ions of some of these metals are stabilized in acidic solutions. We examined the adsorption capacities of three water-soluble functional polymers, namely archaeal poly-γ-glutamate (L-PGA), polyacrylate (PAC), and polyvinyl alcohol (PVA), for six valuable metal ions (Co(2+), Ni(2+), Mn(2+), Ga(3+), In(3+), and Dy(3+)). All three polymers showed apparently little or no capacity for divalent cations, whereas L-PGA and PAC showed the potential to adsorb trivalent cations, implying the beneficial valence-dependent selectivity of anionic polyelectrolytes with multiple carboxylates for metal ions. PVA did not adsorb metal ions, indicating that the crucial role played by carboxyl groups in the adsorption of crucial metal ions cannot be replaced by hydroxyl groups under the conditions. In addition, equilibrium studies using the non-ideal competitive adsorption model indicated that the potential for L-PGA to be used for the removal (or collection) of water-soluble critical metal ions (e.g., Ga(3+), In(3+), and Dy(3+)) was far superior to that of any other industrially-versatile PAC materials.

  9. A simple alkali-metal and noble gas ion source for SIMS equipments with mass separation of the primary ions

    International Nuclear Information System (INIS)

    Duesterhoeft, H.; Pippig, R.

    1986-01-01

    An alkali-metal ion source working without a store of alkali-metals is described. The alkali-metal ions are produced by evaporation of alkali salts and ionization in a low-voltage arc discharge stabilized with a noble gas plasma or in the case of small alkali-metal ion currents on the base of the well known thermic ionization at a hot tungsten wire. The source is very simple in construction and produces a stable ion current of 0.3 μA for more than 100 h. It is possible to change the ion species in a short time. This source is applicable to all SIMS equipments using mass separation for primary ions. (author)

  10. Biosorption of heavy metal ions from aqueous solution by red macroalgae.

    Science.gov (United States)

    Ibrahim, Wael M

    2011-09-15

    Biosorption is an effective process for the removal and recovery of heavy metal ions from aqueous solutions. The biomass of marine algae has been reported to have high biosorption capacities for a number of heavy metal ions. In this study, four species of red seaweeds Corallina mediterranea, Galaxaura oblongata, Jania rubens and Pterocladia capillacea were examined to remove Co(II), Cd(II), Cr(III) and Pb(II) ions from aqueous solution. The experimental parameters that affect the biosorption process such as pH, contact time and biomass dosage were studied. The maximum biosorption capacity of metal ions was 105.2mg/g at biomass dosage 10 g/L, pH 5 and contact time 60 min. The biosorption efficiency of algal biomass for the removal of heavy metal ions from industrial wastewater was evaluated for two successive cycles. Galaxaura oblongata biomass was relatively more efficient to remove metal ions with mean biosorption efficiency of 84%. This study demonstrated that these seaweeds constitute a promising, efficient, cheap and biodegradable sorbent biomaterial for lowering the heavy metal pollution in the environment. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Microstructured liquid metal electron and ion sources (MILMES/MILMIS)

    Energy Technology Data Exchange (ETDEWEB)

    Mitterauer, J [Technische Universitaet Wien (Austria). Institut fuer Allgemeine Elektrotechnik und Elektronik

    1997-12-31

    Ion or electron beams can be emitted from liquid metal wetted needles, or from capillaries or slits into which the liquid metal is allowed to flow. Large-area liquid metal field emission sources have been proposed recently, using either two-dimensional, regular arrays of cones or capillaries, or even a substrate with an intrinsically microstructured surface covered by a liquid metal film. This latter concept has been realized in a pilot experiment by in situ wicking and wetting of a porous sintered metal disc. Microstructured liquid metal ion or electron sources are capable of operating in a pulsed mode at a current level which is orders of magnitude above that for steady-state operation. (author). 3 figs., 10 refs.

  12. Nanostructured films of metal particles obtained by laser ablation

    Energy Technology Data Exchange (ETDEWEB)

    Muniz-Miranda, M., E-mail: muniz@unifi.it [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Gellini, C. [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Giorgetti, E.; Margheri, G.; Marsili, P. [Istituto Sistemi Complessi (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Lascialfari, L.; Becucci, L. [Dipartimento di Chimica “U. Schiff”, Università di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Trigari, S. [Istituto Sistemi Complessi (CNR), Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Giammanco, F. [Dipartimento di Fisica “E. Fermi”, Università di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy)

    2013-09-30

    Colloidal dispersions of silver and gold nanoparticles were obtained in pure water by ablation with nanosecond pulsed laser. Then, by filtration of the metal particles on alumina, we fabricated nanostructured films, whose surface morphology was examined by atomic force microscopy (AFM) and related to surface-enhanced Raman scattering (SERS) after adsorption of adenine. - Highlights: • Ag and Au colloidal nanoparticles were obtained by laser ablation. • Nanostructured Ag and Au films were fabricated by filtration of metal nanoparticles. • Surface morphology of metal films was investigated by atomic force microscopy. • Surface-enhanced Raman spectra (SERS) of adenine on metal films were obtained. • SERS enhancements were related to the surface roughness of the metal films.

  13. Ultraviolet spectroscopy and metal ions detection

    International Nuclear Information System (INIS)

    Chaudry, M.A.

    1995-01-01

    The spectrochemical analysis is based on the interaction of radiation with the chemical species and depends on their nature, having pi, sigma or electrons, or d and f electrons, UV. Visible spectrophotometry has been used extensively in the detection and determination of both organics and inorganics. In UV detection the sensitivity is proportional to the bath length and the excitation coefficient of the given sample. It may be insensitive to many species unless these are converted to UV, absorbing derivatives. The technique has been applied for the monitoring of the effluents from HPLC, as chlorides or other complexes of various elements in this article the utility of HCl as reagent for the spectrophotometric determination of the metal ions like Al(III), As(III,IV), Ba(II), Cd(II), Ca(II) Ce(III), Cs(i), Cr(III,VI), Co(II), Cu(II), Dy(III), Eu(III), Gd(III), Au(III), Hf(IV), Ho(III), In(III), Fe(III), La(III), Pb(II), Lu (III), Mg(II), Mn(II), Hg(II), Mo(VI), Ni(II), Pd(II), Pt(IV), K(I), Pr(III), Re(VII), Ru(IV), Sm(III), Sc(III), Ag(I), Sr(II) Te(III), Th(IV), Sn(II,IV), Ti(III,IV), W(VI), U(VI), V(IV,V), Yb(III), Zn(II) AND Zr(IV) Ions i.e. for meta ions from d of the most of these metal ions has been found sufficient permit their detection in HPLC. Their molar absorptive have also been reported. Reference has also been provided to post column derivatization of some metal ions from d and f block elements for their detection in HPLC. (author) 12 figs.; 6 tabs.; 27 refs

  14. Polyrhodanine modified anodic aluminum oxide membrane for heavy metal ions removal.

    Science.gov (United States)

    Song, Jooyoung; Oh, Hyuntaek; Kong, Hyeyoung; Jang, Jyongsik

    2011-03-15

    Polyrhodanine was immobilized onto the inner surface of anodic aluminum oxide (AAO) membrane via vapor deposition polymerization method. The polyrhodanine modified membrane was applied to remove heavy metal ions from aqueous solution because polyrhodanine could be coordinated with specific metal ions. Several parameters such as initial metal concentration, contact time and metal species were evaluated systematically for uptake efficiencies of the fabricated membrane under continuous flow condition. Adsorption isotherms of Hg(II) ion on the AAO-polyrhodanine membrane were analyzed with Langmuir and Freundlich isotherm models. The adsorption rate of Hg(II) ion on the membrane was obeyed by a pseudo-second order equation, indicating the chemical adsorption. The maximum removal capacity of Hg(II) ion onto the fabricated membrane was measured to be 4.2 mmol/g polymer. The AAO-polyrhodanine membrane had also remarkable uptake performance toward Ag(I) and Pb(II) ions. Furthermore, the polyrhodanine modified membrane could be recycled after recovery process. These results demonstrated that the polyrhodanine modified AAO membrane provided potential applications for removing the hazardous heavy metal ions from wastewater. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Interaction of Hydroxyproline with Bivalent Metal Ions in Chemical ...

    African Journals Online (AJOL)

    NICO

    The stability constants of the ML and ML2 complex species of some metal ions, namely beryllium(II) and cobalt(II), with hydroxyproline were ... metal ions have several significant applications in biological systems.3–20 Beryllium is one ... 1 filter paper for chromatography was used for the purpose of electrophoresis. An Elico ...

  16. Emission of positive oxygen ions from ion bombardment of adsorbate-covered metal surfaces

    International Nuclear Information System (INIS)

    Kaurin, M.G.

    1989-01-01

    During ion bombardment of metal surfaces, collision cascades can result in the emission of sputtered secondary ions. Recent experiments, however, have suggested that the emission of positive ions of electronegative adsorbates can result from electronic processes rather than from processes involving elastic collisions. This dissertation presents the results of experiments studying the emission of positive oxygen ions from oxygen- and carbon-monoxide-covered transition metal surfaces during bombardment by 25-250 keV ions of neon, argon, and krypton. The systems studied may be grouped into four categories. For a nickel substrate with adsorbed oxygen, the emission of positive oxygen ions proceeds through collision cascades. For titanium and niobium with adsorbed oxygen, the emission of positive oxygen ions is proportional to the primary ion velocity, consistent with emission from electronic processes; for a given primary ion velocity, the oxygen ion yield is independent of primary ion species. For substrates of molybdenum and tungsten, the oxygen yield is proportional to primary ion velocity, but the yield also depends on the primary ion species for a given primary ion velocity in a manner that is consistent with emission resulting from electronic processes. For these two groups, except for titanium, the yields during neon ion bombardment do not extrapolate (assuming linearity with primary ion velocity) to a nonzero value at zero beam velocity. The magnitude of the oxygen ion yields from these targets is not consistent with that expected if the emission were induced by secondary electrons emitted during the ion bombardment

  17. High-current pulsed ion source for metallic ions

    International Nuclear Information System (INIS)

    Gavin, B.; Abbott, S.; MacGill, R.; Sorensen, R.; Staples, J.; Thatcher, R.

    1981-03-01

    A new sputter-ion PIG source and magnet system, optimized for intermediate charge states, q/A of 0.02 to 0.03, is described. This source will be used with the new Wideroe-based injector for the SuperHILAC. Pulsed electrical currents of several emA of heavy metal ions have been produced in a normalized emittance area of .05π cm-mr. The source system is comprised of two electrically separate anode chambers, one in operation and one spare, which can be selected by remote control. The entire source head is small and quickly removable

  18. Alzheimer’s disease: How metal ions define β-amyloid function

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2017-01-01

    focuses on the essential coordination chemistry and biochemistry that relate transition metal ions iron, copper, and zinc to β-amyloid (Aβ) and most likely define the peptide's roles in neurons. The metal-Aβ interactions have elements of both gain of toxic function, as usually considered, but also loss......Alzheimer’s disease is increasingly recognized to be linked to the function and status of metal ions, and recently, the amyloid hypothesis has been strongly intertwined with the metal ion hypothesis; in fact, these two hypotheses fit well together and are not mutually contradictory. This review...... of natural functions, as emphasized in this review. Both these aspects and their relationships are discussed and their implications for future therapeutic strategies are outlined....

  19. Adsorption of heavy metal ions by sawdust of deciduous trees

    International Nuclear Information System (INIS)

    Bozic, D.; Stankovic, V.; Gorgievski, M.; Bogdanovic, G.; Kovacevic, R.

    2009-01-01

    The adsorption of heavy metal ions from synthetic solutions was performed using sawdust of beech, linden and poplar trees. The adsorption depends on the process time, pH of the solution, type of ions, initial concentration of metals and the sawdust concentration in suspension. The kinetics of adsorption was relatively fast, reaching equilibrium for less than 20 min. The adsorption equilibrium follows Langmuir adsorption model. The ion exchange mechanism was confirmed assuming that the alkali-earth metals from the adsorbent are substituted by heavy metal ions and protons. On lowering the initial pH, the adsorption capacity decreased, achieving a zero value at a pH close to unity. The maximum adsorption capacity (7-8 mg g -1 of sawdust) was achieved at a pH between 3.5 and 5 for all the studied kinds of sawdust. The initial concentration of the adsorbate and the concentration of sawdust strongly affect the process. No influence of particles size was evidenced. A degree of adsorption higher than 80% can be achieved for Cu 2+ ions but it is very low for Fe 2+ ions, not exceeding 10%.

  20. Enhancement of oxygen reduction at Fe tetrapyridyl porphyrin by pyridyl-N coordination to transition metal ions

    International Nuclear Information System (INIS)

    Maruyama, Jun; Baier, Claudia; Wolfschmidt, Holger; Bele, Petra; Stimming, Ulrich

    2012-01-01

    One of the promising candidates as noble-metal-free electrode catalysts for polymer electrolyte fuel cells (PEFCs) is a carbon material with nitrogen atoms coordinating iron ions embedded on the surface (Fe-N x moiety) as the active site, although the activity is insufficient compared to conventional platinum-based electrocatalysts. In order to obtain fundamental information on the activity enhancement, a simple model of the Fe-N x active site was formed by adsorbing 5,10,15,20-Tetrakis(4-pyridyl)-21H,23H-porphine iron(III) chloride (FeTPyPCl) on the basal plane of highly oriented pyrolytic graphite (HOPG), and cathodic oxygen reduction was investigated on the surface in 0.1 M HClO 4 . The catalytic activity for oxygen reduction was enhanced by loading transition metal ions (Co 2+ , Ni 2+ , Cu 2+ ) together with FeTPyPCl. The X-ray photoelectron spectrum of the surface suggested that the metal was coordinated by the pyridine-N. The enhancement effect of the transition metals was supported by two different measurements: oxygen reduction at HOPG in 0.1 M HClO 4 dissolving FeTPyPCl and the metal ions; oxygen reduction in 0.1 M HClO 4 at the subsequently well-rinsed and dried HOPG. The ultraviolet–visible spectrum for the solution also suggested the coordination between the pyridyl-N and the metal ions. The oxygen reduction enhancement was attributed to the electronic interaction between the additional transition metal and the Fe center of the porphyrin through the coordination bonds. These results implied that the improvement of the activity of the noble-metal-free catalyst would be possible by the proper introduction of the transition metal ions around the active site.

  1. Removal of mercury ion from aqueous solution by activated carbons obtained from biomass and coals

    Energy Technology Data Exchange (ETDEWEB)

    Ekinci, E.; Yardim, F. [Faculty of Chemical Engineering, Istanbul Technical University, Ayazaga, 80626 Istanbul (Turkey); Budinova, T.; Petrov, N.; Razvigorova, M.; Minkova, V. [Institute of Organic Chemistry, Bulgarian Academy of Sciences, Acad.G.Bonchev, str. bl. 9, Sofia (Bulgaria)

    2002-06-20

    The adsorption of Hg(II) from aqueous solution at 293 K by activated carbons obtained from apricot stones, furfural and coals was studied. Adsorption studies were performed under the varying conditions of time of treatment, metal ion concentration and pH. The process of adsorption followed Langmuir isotherm. The removal of Hg(II) increased with the increase of pH of the solution from 2 to 5 and remained constant up to pH 10. Desorption studies were preformed.

  2. Effects of complexing compounds on sorption of metal ions to cement

    Energy Technology Data Exchange (ETDEWEB)

    Loevgren, Lars [Umeaa Univ. (Sweden). Inorganic chemistry

    2005-12-15

    This present report is a literature review addressing the effects of complexing ligands on the sorption of radionuclides to solid materials of importance for repositories of radioactive waste. Focus is put on laboratory studies of metal ion adsorption to cement in presence of chelating agents under strongly alkaline conditions. As background information, metal sorption to different mineral and cement phases in ligand free systems is described. Furthermore, surface complexation model (SCM) theories are introduced. According to surface complexation theories these interactions occur at specific binding sites at the particle/water interface. Adsorption of cationic metals is stronger at high pH, and the adsorption of anions occurs preferentially at low pH. The adsorption of ions to mineral surfaces is a result of both chemical bonding and electrostatic attraction between the ions and charged mineral surfaces. By combining uptake data with spectroscopic information the sorption can be explained on a molecular level by structurally sound surface complexation models. Most of the metal sorption studies reviewed are dealing with minerals exhibiting oxygen atoms at their surfaces, mainly oxides of Fe(II,III) and Al(III), and aluminosilicates. Investigations of radionuclides are focused on clay minerals, above all montmorillonite and illite. Which mechanism that is governing the metal ion adsorption to a given mineral is to a large extent depending on the metal adsorbed. For instance, sorption of Ni to montmorillonite can occur by formation of inner-sphere mononuclear surface complexes located at the edges of montmorillonite platelets and by formation of a Ni phyllosilicate phase parallel to montmorillonite layers. Also metal uptake to cement materials can occur by different mechanisms. Cationic metals can both be attached to cement (calcium silicate hydrate, CSH) and hardened cement paste (HCP) by formation of inner-sphere complexes at specific surface sites and by

  3. Metal-ion interactions and the structural organization of Sepia eumelanin.

    Science.gov (United States)

    Liu, Yan; Simon, John D

    2005-02-01

    The structural organization of melanin granules isolated from ink sacs of Sepia officinalis was examined as a function of metal ion content by scanning electron microscopy and atomic force microscopy. Exposing Sepia melanin granules to ethelenediaminetetraacetic acid (EDTA) solution or to metal salt solutions changed the metal content in the melanin, but did not alter granular morphology. Thus ionic forces between the organic components and metal ions in melanin are not required to sustain the natural morphology once the granule is assembled. However, when aqueous suspensions of Sepia melanin granules of varying metal content are ultra-sonicated, EDTA-washed and Fe-saturated melanin samples lose material to the solution more readily than the corresponding Ca(II) and Mg(II)-loaded samples. The solubilized components are found to be 5,6-dihydroxyindole-2-carboxylic acid (DHICA)-rich constituents. Associated with different metal ions, Na(I), Ca(II) and Mg(II) or Fe(III), these DHICA-rich entities form distinct two-dimensional aggregation structures when dried on the flat surface of mica. The data suggest multiply-charged ions play an important role in assisting or templating the assembly of the metal-free organic components to form the three-dimensional substructure distributed along the protein scaffold within the granule.

  4. The effect of metal ion exchange and alkali metal doping on the electrical conductivity of the Faujasite-type zeolite 13X

    International Nuclear Information System (INIS)

    Swart, S.

    1983-12-01

    Zeolite 13X was synthesized in the sodium form. Some transition metal cations were introduced into the zeolite framework by ion exchange reactions. These different cationic zeolite forms were doped or impregnated with sodium metal, utilizing the adsorptive properties of the zeolite. An A.C. technique was used to determine the electrical conductivity of the dehydrated ion exchanged zeolites and the sodium impregnated zeolite samples as a function of temperature. The conductivity value obtained was used to determine some thermodynamic parameters relating to the conduction process. For the dehydrated ion exchanged zeolites the electrical conductivity showed a general decrease with a decreasing ion exchange capacity. The sodium impregnated zeolites showed an increase in conductivity with respect to the dehydrated unimpregnated samples. This was attributed to the presence of Na 6 5 + centres in the impregnated zeolites. The reduction of some of the metal cations by the sodium on impregnation did not appear to have any significant effect on the overall ionic conductivity of the samples. The conductivity as a function of temperature and pressure for the dehydrated sodium form of zeolite 13X and its impregnated counterpart was determined. The conductivity was found to increase with increasing pressure and temperature

  5. Defect-impurity interactions in ion-implanted metals

    International Nuclear Information System (INIS)

    Turos, A.

    1986-01-01

    An overview of defect-impurity interactions in metals is presented. When point defects become mobile they migrate towards the sinks and on the way can be captured by impurity atoms forming stable associations so-called complexes. In some metallic systems complexes can also be formed athermally during ion implantation by trapping point defects already in the collision cascade. An association of a point defect with an impurity atom leads to its displacement from the lattice site. The structure and stability of complexes are strongly temperature dependent. With increasing temperature they dissociate or grow by multiple defect trapping. The appearance of freely migrating point defects at elevated temperatures, due to ion bombardment or thermal annealing, causes via coupling with defect fluxes, important impurity redistribution. Because of the sensitivity of many metal-in-metal implanted systems to radiation damage the understanding of this processes is essential for a proper interpretation of the lattice occupancy measurements and the optimization of implantation conditions. (author)

  6. Metal ion interaction of an oligopeptide fragment representing the regulatory metal binding site of a CueR protein

    DEFF Research Database (Denmark)

    Jancsó, Attila; Szokolai, Hajnalka; Roszahegyi, Livia

    2013-01-01

    Metalloregulatory proteins of the MerR family are transcriptional activators that sense/control the concentration of various metal ions inside bacteria.1 The Cu+ efflux regulator CueR, similarly to other MerR proteins, possesses a short multiple Cys-containing metal binding loop close to the C...... of cognate metal ions.2 Nevertheless, it is an interesting question whether the same sequence, when removed from the protein, shows a flexibility to adopt different coordination environments and may efficiently bind metal ions having preferences for larger coordination numbers....

  7. Heavy metal ion uptake properties of polystyrene-supported ...

    Indian Academy of Sciences (India)

    Unknown

    concentration on the uptake of metal ions have been studied. The uptake ... employed for the removal of heavy metal pollutants from industrial waste water. ... nitrate, mercuric chloride, cadmium nitrate and potassium dichromate salts. ... polymer resin was determined by reacting 50, 100, 150, 200, 250 and 300 ppm of metal.

  8. 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.

  9. Investigation of metal ions in fusion plasmas using emission spectroscopy

    International Nuclear Information System (INIS)

    Tale, I.

    2005-01-01

    Full text: The Latvian and Portugal Associations are performing development of advanced plasma - facing system using the liquid metal limiter. The objectives of this project require study of the influence of the liquid metal limiter on the main plasma parameters, including concentration of evaporated metal atoms in plasma. The fusion plasmas are related to the dense hot plasmas. The required average ion temperature according to the ITER project (International Thermonuclear Experimental Reactor) is 8,0 keV (9,3 x 10 7 0 K), the average electron temperature - 8,9 keV (1,04 x 10 8 0 K). Plasma temperature operated in the research tokamak ISSTOK, involved in testing of liquid metal limiter concept is considerably less, being of order of 10 50 K. The ionization degree of metal atoms considerably depends on the plasma ion temperature. Density of metal vapours in plasma can be estimated using the following two spectroscopic methods: The fluorescence of the multiple ionised metal ions in steady state concentration; The charge exchange emission during ionisation of evaporated metal ions. In the first step of development of testing system of metal vapours the equipment and instrumentation for charge exchange spectroscopy of Ga and In has been elaborated taking into account the following features of plasma emission. The Ga emission lines occur on the background high temperature plasma black body emission and stray light. Radial distribution of Ga in plasma in the facing plane of Ga flux is desirable

  10. Application of monocarboxylic acids for the extraction of metal ions-literature survey

    International Nuclear Information System (INIS)

    Brzozka, Z.; Rozycki, C.

    1980-01-01

    In the paper there is presented a literature review concerning the application of monocarboxylic acids for extraction of metal ions. The following problems are discussed: characteristic of monocarboxylic acids and their mixtures, the equilibria between the acid solution in organic solvent and aqueous phase, the mechanism of acid partition, complexes of carboxylic acids and metal ions in aqueous phase, mechanism of extraction by means of carboxylic acids as well as the problems concerning the extraction of individual metal ions. Data about the extraction of metal ions are presented in table. The 138 references are given. (author)

  11. Uptake of metal ions by a silica-based tetraphenylporphyrin sorbent

    Energy Technology Data Exchange (ETDEWEB)

    Pyrzynska, K.; Sadowska, M.; Trojanowicz, M.

    1999-09-01

    The [5-p-carboxyphenyl-10,15,20-triphenyl]porphyrin (TPP) covalently attached to aminopropyl silica gel was examined with respect to the sorption of transition metal ions. The distribution coefficients (K{sub d}) are reported for some metal ions with this new sorbent as a function of pH. It was found that in optimum pH conditions the sorption of Cu(II) and Fe(III) is much faster than that of Co(II) and Cr(III). The binding of metal ions is strongly affected by the presence of various species accelerating the complex formation. The application of porphyrin ligands for preconcentration and metal-matrix separation was also examined using complex formation in solution coupled with an anion exchange resin and column chelation procedure, e.g. sorption of metal on an anion exchanger previously loaded with tetra(4-carboxyphenyl)porphyrin.

  12. Oxidative damage to collagen and related substrates by metal ion/hydrogen peroxide systems

    DEFF Research Database (Denmark)

    Hawkins, C L; Davies, Michael Jonathan

    1997-01-01

    . In this study electron paramagnetic resonance spectroscopy with spin trapping has been used to identify radicals formed on collagen and related materials by metal ion-H2O2 mixtures. Attack of the hydroxyl radical, from a Fe(II)-H2O2 redox couple, on collagen peptides gave signals from both side chain (.CHR...... are similar to those from the alpha-carbon site of peptides and the side-chain of lysine. Enzymatic digestion of the large, protein-derived, species releases similar low-molecular-weight adducts. The metal ion employed has a dramatic effect on the species observed. With Cu(I)-H2O2 or Cu(II)-H2O2 instead of Fe(II)-H......2O2, evidence has been obtained for: i) altered sites of attack and fragmentation, ii) C-terminal decarboxylation, and iii) hydrogen abstraction at N-terminal alpha-carbon sites. This altered behaviour is believed to be due to the binding of copper ions to some substrates and hence site...

  13. Preparation of metal ion exchange resin by radiation-induced graft copolymerization

    International Nuclear Information System (INIS)

    Nakase, Yoshiaki; Akasaka, Nobuhiro.

    1982-06-01

    Radiation-induced graft copolymerization of 2-acrylamide-2-methyl propane sulfonic acid (AMPS) onto polyvinylchloride (PVC) and polyvinylidene chloride resin (PVD) was investigated in the water-acetone system and their adsorptive activities to metal ion were also examined. In the case of PVC, the degree of grafting increased with the increase of acetone content, but the adsorptive activity to metal ions (mainly lithic ion) became maximum in the system with water/acetone of 2/3. Grafted PVC prepared at about 35 0 C and at a higher concentration of AMPS showed higher adsorption activity than the other cases. In the case of PVD, a similar result was obtained with the case of PVC except the temperature dependence and effect of swelling agent. Polymerizations at temperatures of 35 and 50 0 C showed no effect on the degree of grafting, and the usage of a swelling agent was quite effective to the adsorptive activity. Glass transition temperature of the grafted copolymer was the same as that of original polymer, and their thermal stability was confirmed up to the temperature at which homopolymer of AMPS decomposed, about 180 0 C. (author)

  14. Coordination of cassava starch to metal ions and thermolysis of ...

    African Journals Online (AJOL)

    Cassava starch formed Werner-type complexes with ions of metals from the transition groups. This was proven by conductivity and electron paramagnetic resonance measurements. The coordination of starch to central metal ions influenced the thermal decomposition of starch. As a rule complexes started to decompose at ...

  15. Plasma immersion ion implantation for reducing metal ion release

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, C.; Garcia, J. A.; Maendl, S.; Pereiro, R.; Fernandez, B.; Rodriguez, R. J. [Centro de Ingenieria Avanzada de Superficies AIN, 31191, Cordovilla-Pamplona (Spain); Leibniz-Institut fuer Oberflaechenmodifizierung, 04318 Leipzig (Germany); Universidad de Oviedo, Departamento Quimica Fisica y Analitica (Spain); Centro de Ingenieria Avanzada de Superficies AIN, 31191, Cordovilla-Pamplona (Spain)

    2012-11-06

    Plasma immersion ion implantation of Nitrogen and Oxygen on CoCrMo alloys was carried out to improve the tribological and corrosion behaviors of these biomedical alloys. In order to optimize the implantation results we were carried experiments at different temperatures. Tribocorrosion tests in bovine serum were used to measure Co, Cr and Mo releasing by using Inductively Coupled Plasma Mass Spectrometry analysis after tests. Also, X-ray Diffraction analysis were employed in order to explain any obtained difference in wear rate and corrosion tests. Wear tests reveals important decreases in rate of more than one order of magnitude for the best treatment. Moreover decreases in metal release were found for all the implanted samples, preserving the same corrosion resistance of the unimplanted samples. Finally this paper gathers an analysis, in terms of implantation parameters and achieved properties for industrial implementation of these treatments.

  16. Spectroscopic properties of Yb3+ and Er3+ ions in heavy metal glasses

    International Nuclear Information System (INIS)

    Pisarski, Wojciech A.; Grobelny, Lukasz; Pisarska, Joanna; Lisiecki, Radoslaw; Ryba-Romanowski, Witold

    2011-01-01

    Highlights: → Heavy metal glasses doubly doped with Yb 3+ and Er 3+ were examined. → NIR luminescence at about 1530 nm and green and red up-conversion spectra were detected. → The unusual large spectral linewidth nearly close to 110 nm for 4 I 13/2 - 4 I 15/2 transition of Er 3+ ions in Yb-Er co-doped lead borate glass was obtained. → Long-lived NIR luminescence was detected in lead germanate glass. → The NIR luminescence and up-conversion phenomena strongly depend on stretching vibrations of glass host. - Abstract: Selected heavy metal glasses containing Yb 3+ and Er 3+ ions have been studied. Near-infrared luminescence spectra at 1.53 μm and up-conversion spectra of Er 3+ ions were registered under excitation of Yb 3+ ions by 975 nm diode laser line. The luminescence bands correspond to 4 I 13/2 - 4 I 15/2 (NIR), 4 S 3/2 - 4 I 15/2 (green) and 4 F 9/2 - 4 I 15/2 (red) transitions of Er 3+ , respectively. The optical transitions of rare earth ions have been examined as a function of glass host. The unusual large spectral linewidth nearly close to 110 nm for 4 I 13/2 - 4 I 15/2 transition of Er 3+ ions in Yb-Er co-doped lead borate glass was obtained, whereas long-lived NIR luminescence at 1.53 μm was detected in lead germanate glass. The NIR luminescence and up-conversion phenomena strongly depend on stretching vibrations of glass host, which was confirmed by FT-IR spectroscopy.

  17. Metal is not inert: role of metal ions released by biocorrosion in aseptic loosening--current concepts.

    Science.gov (United States)

    Cadosch, Dieter; Chan, Erwin; Gautschi, Oliver P; Filgueira, Luis

    2009-12-15

    Metal implants are essential therapeutic tools for the treatment of bone fractures and joint replacements. The metals and metal alloys used in contemporary orthopedic and trauma surgery are well tolerated by the majority of patients. However, complications resulting from inflammatory and immune reactions to metal implants have been well documented. This review briefly discusses the different mechanisms of metal implant corrosion in the human body, which lead to the release of significant levels of metal ions into the peri-implant tissues and the systemic blood circulation. Additionally, this article reviews the effects of the released ions on bone metabolism and the immune system and discusses their involvement in the pathophysiological mechanisms of aseptic loosening and metal hypersensitivity in patients with metal implants.

  18. Separation of strontium ions from other alkaline earth metal ions using masking reagent

    International Nuclear Information System (INIS)

    Komatsu, Y.

    1996-01-01

    Cs + and Sr 2+ have been well known as serious elements in high level radioactive waste. Separation of Cs + has already been successful when using an ion-exchange method from solution in the presence of other alkali metal ions. The separation of Sr 2+ is, however, not so easy by any known separation method such as solvent-extraction and ion-exchange methods. This is because Sr 2+ is in the middle of the selectivity series, which is Mg 2+ > Ca 2+ > Sr 2+ > Ba 2+ for the solvent-extraction method and Ba 2+ > Sr 2+ > Ca 2+ > Mg 2+ for the ion- exchange method. In the present study, separation of strontium from other alkaline earth metal ions was studied by a combined use of three types of separation methods at 298 K: the solvent-extraction method was applied for the first separation, in which thenoyltrifluoroacetone (TTA, extractant) and trioctylphosphine oxide ( TOPO, adduct forming ligand) were used for the organic phase of the system. The separation factors for each combination of four alkaline earth metal ions were determined by the values of the distribution ratio. The Mg 2+ was well separated from Sr 2+ by the TTA-TOPO system. However, the separation of the combinations of Ca 2+ -Sr 2+ and Sr 2+ -Ba 2+ was not complete by the above solvent-extraction system. The second separation method, an ion-exchange method was applied using dihydrogen tetratitanate hydrate fibers (H 2 Ti 4 O 9 nH 2 O) as an ion exchanger to separate Sr 2+ and Ba 2+ . The separation factors for each combination of four alkaline earth metal ions were calculated by the values of the distribution coefficients. Ba 2+ was well separated from Sr 2+ by the ion-exchange method. To separate Ca 2+ and Sr 2+ , however, a modified solvent-extraction method was finally used in which H 2 Ti 4 O 9 nH 2 O was used as a masking reagent of Sr 2+ . After the dihydrogen tetratitanate hydrate fibers were contacted with the aqueous solution containing Ca 2+ and Sr 2+ , the organic solution containing TTA and TOPO

  19. Development of a method employing chitosan to remove metallic ions from wastewater

    International Nuclear Information System (INIS)

    Janegitz, Bruno Campos; Lourencao, Bruna Claudia; Lupetti, Karina Omuro; Fatibello-Filho, Orlando

    2007-01-01

    In this work a method was developed for removing metallic ions from wastewaters by co-precipitation of Cu 2+ , Pb 2+ , Cd 2+ , Cr 3+ and Hg 2+ with chitosan and sodium hydroxide solution. Solutions of these metallic ions in the range from 0.55 to 2160 mg L -1 were added to chitosan dissolved in 0.05 mol L -1 HCl. For the co-precipitation of metal-chitosan-hydroxide a 0.17 mol L -1 NaOH solution was added until pH 8.5-9.5. A parallel study was carried out applying a 0.17 mol L -1 NaOH solution to precipitate those metallic ions. Also, a chitosan solid phase column was used for removing those metallic ions from wastewaters. (author)

  20. Kinetic study of heavy metal ions removal by ion exchange in batch conical air spouted bed

    Directory of Open Access Journals (Sweden)

    T.M. Zewail

    2015-03-01

    Full Text Available Spouted bed contactor is a hybrid of fixed and fluidized bed contactors, which retains the advantages of each with good hydrodynamic conditions. The aim of the present study is to investigate the performance of a batch conical air spouted vessel for heavy metal removal by strong cation exchange resins (AMBERJET 1200 Na. The effect of various parameters such as type of heavy metal ions (Ni+2 and Pb+2, contact time, superficial air velocity and initial heavy metal ion concentration on % heavy metal ion removal has been investigated. It has been found that under optimum conditions 98% and 99% removal of Ni+2 and Pb+2 were achieved respectively. Several kinetic models were used to test the experimental data and to examine the controlling mechanism of the sorption process. The present results of Ni+2 and Pb+2 well fit pseudo second order kinetic model with a high correlation coefficient. Both film diffusion and intra-particle diffusion contribute to the ion exchange process. The present study revealed that spouted bed vessel may provide an effective alternative for conducting ion exchange reactions.

  1. Periodic table of 3d-metal dimers and their ions.

    Science.gov (United States)

    Gutsev, G L; Mochena, M D; Jena, P; Bauschlicher, C W; Partridge, H

    2004-10-08

    The ground states of the mixed 3d-metal dimers TiV, TiCr, TiMn, TiFe, TiCo, TiNi, TiCu, TiZn, VCr, VMn, VFe, VCo, VNi, VCu, VZn, CrMn, CrFe, CrCo, CrNi, CrCu, CrZn, MnFe, MnCo, MnNi, MnCu, MnZn, FeCo, FeNi, FeCu, FeZn, CoNi, CoCu, CoZn, NiCu, NiZn, and CuZn along with their singly negatively and positively charged ions are assigned based on the results of computations using density functional theory with generalized gradient approximation for the exchange-correlation functional. Except for TiCo and CrMn, our assignment agrees with experiment. Computed spectroscopic constants (r(e),omega(e),D(o)) are in fair agreement with experiment. The ground-state spin multiplicities of all the ions are found to differ from the spin multiplicities of the corresponding neutral parents by +/-1. Except for TiV, MnFe, and MnCu, the number of unpaired electrons, N, in a neutral ground-state dimer is either N(1)+N(2) or mid R:N(1)-N(2)mid R:, where N(1) and N(2) are the numbers of unpaired 3d electrons in the 3d(n)4s(1) occupation of the constituent atoms. Combining the present and previous results obtained at the same level of theory for homonuclear 3d-metal and ScX (X=Ti-Zn) dimers allows one to construct "periodic" tables of all 3d-metal dimers along with their singly charged ions.

  2. MCTBI: a web server for predicting metal ion effects in RNA structures.

    Science.gov (United States)

    Sun, Li-Zhen; Zhang, Jing-Xiang; Chen, Shi-Jie

    2017-08-01

    Metal ions play critical roles in RNA structure and function. However, web servers and software packages for predicting ion effects in RNA structures are notably scarce. Furthermore, the existing web servers and software packages mainly neglect ion correlation and fluctuation effects, which are potentially important for RNAs. We here report a new web server, the MCTBI server (http://rna.physics.missouri.edu/MCTBI), for the prediction of ion effects for RNA structures. This server is based on the recently developed MCTBI, a model that can account for ion correlation and fluctuation effects for nucleic acid structures and can provide improved predictions for the effects of metal ions, especially for multivalent ions such as Mg 2+ effects, as shown by extensive theory-experiment test results. The MCTBI web server predicts metal ion binding fractions, the most probable bound ion distribution, the electrostatic free energy of the system, and the free energy components. The results provide mechanistic insights into the role of metal ions in RNA structure formation and folding stability, which is important for understanding RNA functions and the rational design of RNA structures. © 2017 Sun et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  3. Methods for obtaining a uniform volume concentration of implanted ions

    International Nuclear Information System (INIS)

    Reutov, V.F.

    1995-01-01

    Three simple practical methods of irradiations with high energy particles providing the conditions for obtaining a uniform volume concentration of the implanted ions in the massive samples are described in the present paper. Realization of the condition of two-sided irradiation of a plane sample during its rotation in the flux of the projectiles is the basis of the first method. The use of free air as a filter with varying absorbent ability due to movement of the irradiated sample along ion beam brought to the atmosphere is at the basis of the second method of uniform ion alloying. The third method for obtaining a uniform volume concentration of the implanted ions in a massive sample consists of irradiation of a sample through the absorbent filter in the shape of a foil curved according to the parabolic law moving along its surface. The first method is the most effective for obtaining a great number of the samples, for example, for mechanical tests, the second one - for irradiation in different gaseous media, and the third one - for obtaining high concentrations of the implanted ions under controlled (regulated) thermal and deformation conditions. 2 refs., 7 figs

  4. The ion implantation of metals and engineering materials

    International Nuclear Information System (INIS)

    Dearnaley, G.

    1978-01-01

    An entirely new method of metal finishing, by the process of ion implantation, is described. Introduced at first for semiconductor device applications, this method has now been demonstrated to produce major and long-lasting improvements in the durability of material surfaces, as regards both wear and corrosion. The process is distinct from that of ion plating, and it is not a coating technique. After a general description of ion implantation examples are given of its effects on wear behaviour (mostly in steels and cemented carbides) and on corrosion, in a variety of metals and alloys. Its potential for producing decorative finishes is mentioned briefly. The equipment necessary for carrying out ion implantation for engineering applications has now reached the prototype stage, and manufacture of plant for treating a variety of tools and components is about to commence. These developments are outlined. (author)

  5. Metal ion binding with dehydroannulenes – Plausible two ...

    Indian Academy of Sciences (India)

    WINTEC

    Theoretical investigations have been carried out at B3LYP/6-311++G** level of theory to study the binding ... Alkali metals; dehydroannulenes; binding energy; penetration barrier. 1. .... can be discriminated from larger metal ions by running.

  6. Metal negative ion beam extraction from a radio frequency ion source

    Energy Technology Data Exchange (ETDEWEB)

    Kanda, S.; Yamada, N.; Kasuya, T.; Romero, C. F. P.; Wada, M.

    2015-04-08

    A metal ion source of magnetron magnetic field geometry has been designed and operated with a Cu hollow target. Radio frequency power at 13.56 MHz is directly supplied to the hollow target to maintain plasma discharge and induce self-bias to the target for sputtering. The extraction of positive and negative Cu ion beams have been tested. The ion beam current ratio of Cu{sup +} to Ar{sup +} has reached up to 140% when Ar was used as the discharge support gas. Cu{sup −} ion beam was observed at 50 W RF discharge power and at a higher Ar gas pressure in the ion source. Improvement of poor RF power matching and suppression of electron current is indispensable for a stable Cu{sup −} ion beam production from the source.

  7. Ion-induced effects on metallic nanoparticles

    International Nuclear Information System (INIS)

    Klimmer, Andreas

    2010-01-01

    This work deals with the ion-irradiation of metallic nanoparticles in combination with various substrates. Particle diameters were systematically varied within the range of 2.5-14 nm, inter-particle distances range from 30-120 nm. Irradiations were performed with various inert gas ions with energies of 200 keV, resulting in an average ion range larger than the particle dimensions and therefore the effects of irradiation are mainly due to creation of structural defects within the particles and the underlying substrate as well. The main part of this work deals with ion-induced burrowing of metallic nanoparticles into the underlying substrate. The use of micellar nanoparticles with sharp size distribution combined with AFM and TEM analysis allows a much more detailed look at this effect than other works on that topic so far. With respect to the particle properties also a detailed look on the effect of irradiation on the particle structure would be interesting, which might lead to a deliberate influence on magnetic properties, for example. Within the context of this work, first successful experiments were performed on FePt particles, showing a significant reduction of the ordering temperature leading to the magnetically interesting, ordered L1 0 phase. (orig.)

  8. Adaptation of metal arc plasma source to plasma source ion implantation

    International Nuclear Information System (INIS)

    Shamim, M.M.; Fetherston, R.P.; Conrad, J.R.

    1995-01-01

    In Plasma Source Ion Implantation (PSII) a target is immersed in a plasma and a train of high negative voltage pulses is applied to accelerate ions into the target and to modify the properties in the near surface region. In PSII, until now the authors have been using gaseous species to generate plasmas. However metal ion plasma may be used to modify the surface properties of material for industrial applications. Conventionally the ion implantation of metal ions is performed using beam line accelerators which have complex engineering and high cost. The employment of a metal arc source to PSII has tremendous potential due to its ability to process the conformal surfaces, simple engineering and cost effectiveness. They have installed metal arc source for generation of titanium plasma. Currently, they are investigating the properties of titanium plasma and material behavior of titanium implanted aluminum and 52100 steel. The recent results of this investigation are presented

  9. Architectural design criteria for f-block metal ion sequestering agents. 1998 annual progress report

    International Nuclear Information System (INIS)

    Dixon, D.A.; Hay, B.P.; Paine, R.T.; Raymond, K.N.; Rogers, R.D.; Roundhill, D.M.

    1998-01-01

    'The objective of this project is to provide a means to optimize ligand architecture for f-block metal recognition. The authors strategy builds on an innovative and successful molecular modeling approach in developing polyether ligand design criteria for the alkali and alkaline earth cations. The hypothesis underlying this proposal is that differences in metal ion binding with multidentate ligands bearing the same number and type of donor groups are primarily attributable to intramolecular steric factors. They propose quantifying these steric factors through the application of molecular mechanics models. The research involves close integration of theoretical and experimental chemistry. The experimental work entails synthesizing novel ligands and experimentally determining structures and binding constants for metal ion complexation by series of ligands in which architecture is systematically varied. The theoretical work entails using electronic structure calculations to parameterize a molecular mechanics force field for a range of metal ions and ligand types. The resulting molecular mechanics force field will be used to predict low energy structures for unidentate, bidentate, and multidentate ligands and their metal complexes through conformational searches. Results will be analyzed to assess the relative importance of several steric factors including optimal M-L length, optimal geometry at the metal center, optimal geometry at the donor atoms (complementarity), and conformation prior to binding (preorganization). An accurate set of criteria for the design of ligand architecture will be obtained from these results. These criteria will enable researchers to target ligand structures for synthesis and thereby dramatically reduce the time and cost associated with metal-specific ligand development.'

  10. Adsorption of heavy metal ions by activated charcoal

    International Nuclear Information System (INIS)

    Fujikawa, Mitsuo

    1978-01-01

    The adsorption effect was measured for several kinds of heavy metal ions, Pb 2+ , Cd 2+ , Cu 2+ and Zn 2+ by passing them through activated charcoal beds and changing the pH values of solutions. The test procedure is to keep the pH value of solution more than 10 at first, filter heavy metal hydroxide deposit, measure the remaining ion concentration in filtrate, and also test the influence of the addition of alkali to each kind of ions. The individual test procedure for each kind of ions is explained. As for the Cd ions, after the detailed experimental procedure is explained, the adsorption characteristic line is shown as the relation between the adsorption quantity and the equilibrium concentration of Cd 2+ . The similar test procedure and the adsorption characteristic lines are shown and evaluated about Pb 2+ , Cu 2+ and Zn 2+ . These lines are all linear, but have different adsorption quantity and inclination in relation to heavy metal ion concentration. Concerning the influence of pH to adsorption, the characteristics of pH increase are presented, when alkali is added by various quantities to Zn 2+ , Cu 2+ , Pb 2+ and Cd 2+ . The pH of Pb 2+ increased to about 10 by adding 0.4 cc alkali and saturates, but the pH of the other ions did not saturate by adding less than 1.5 cc alkali. When the water containing heavy metals are treated, Cd 2+ , Pb 2+ , Cu 2+ and Zn 2+ are removed almost satisfactorily by passing them through active charcoal filters and keeping pH at 10. The experimental concentrations are 0.05 ppm at pH 10 in Cd, 0.86 ppm at 10.3 in Pb, 0 ppm at pH 9.6 in Cu, 0.06 ppm at pH 8.8 and 12.4 ppm at pH 9.8 in Zn. (Nakai, Y.)

  11. Fatigue and wear of metalloid-ion-implanted metals

    International Nuclear Information System (INIS)

    Hohmuth, K.; Richter, E.; Rauschenbach, B.; Blochwitz, C.

    1985-01-01

    The effect of metalloid ion implantation on the fatigue behaviour and wear of nickel and two steels has been investigated. These metals were implanted with boron, carbon and nitrogen ions at energies from 30 to 60 keV and with doses from 1 X 10 16 to 1 X 10 18 ions cm -2 at room temperature. The mechanical behaviour of fatigued nickel was studied in push-pull tests at room temperature. Wear measurements were made using a pin-and-disc technique. The surface structure, dislocation arrangement and modification of the implantation profile resulting from mechanical tests on metals which had been implanted with metalloid ions were examined using high voltage electron microscopy, transmission high energy electron diffraction, scanning electron microscopy and Auger electron spectroscopy. It is reported that nitrogen and boron ion implantation improves the fatigue lifetime, changes the number and density of the slip bands and modifies the dislocation arrangements in nickel. The cyclic deformation leads to recrystallization of the boron-ion-induced amorphous structure of nickel and to diffusion of the boron and nitrogen in the direction of the surface. The wear behaviour of steels was improved by implantation of mass-separated ions and by implantation of ions without mass separation. (Auth.)

  12. Phase transformation induced by swift heavy ion irradiation of pure metals

    International Nuclear Information System (INIS)

    Dammak, H.; Dunlop, A.; Lesueur, D.

    1996-01-01

    It is now unambiguously established that high electronic energy deposition (HEED), obtained by swift heavy ion irradiation, plays an important role in the damage processes of pure metallic targets: (i) annealing of the defects created by elastic collisions in Fe, Nb, Ni and Pt, and (ii) creation of additional defects in Co, Fe, Ti and Zr. For Ti, we have recently evidenced by transmission electron microscopy observations that the damage creation by HEED is very important and leads to a phase transformation. Titanium evolves from the equilibrium hcp alpha-phase to the high pressure omega-phase. We studied the influence of three parameters on this phase transformation: ion fluence, electronic stopping power and irradiation temperature. The study of Ti and the results concerning other metals (Fe, Zr, etc.) and the semi-metal Bi allow us to propose criteria to predict in which metals HEED could induce damage: those which undergo a phase transformation under high pressure. As a matter of fact, beryllium is strongly damaged when submitted to HEED and seems to behave very similarly to titanium. The fact that such phase changes from a crystalline form to another form were only observed in those metals in which high pressure phases exist in the pressure-temperature diagram, strongly supports the Coulomb explosion model in which the generation of (i) a shock wave and (ii) collective atomic movements are invoked to account for the observed damage creation. (orig.)

  13. Electrospray droplet exposure to organic vapors: metal ion removal from proteins and protein complexes.

    Science.gov (United States)

    DeMuth, J Corinne; McLuckey, Scott A

    2015-01-20

    The exposure of aqueous nanoelectrospray droplets to various organic vapors can dramatically reduce sodium adduction on protein ions in positive ion mass spectra. Volatile alcohols, such as methanol, ethanol, and isopropanol lead to a significant reduction in sodium ion adduction but are not as effective as acetonitrile, acetone, and ethyl acetate. Organic vapor exposure in the negative ion mode, on the other hand, has essentially no effect on alkali ion adduction. Evidence is presented to suggest that the mechanism by which organic vapor exposure reduces alkali ion adduction in the positive mode involves the depletion of alkali metal ions via ion evaporation of metal ions solvated with organic molecules. The early generation of metal/organic cluster ions during the droplet desolvation process results in fewer metal ions available to condense on the protein ions formed via the charged residue mechanism. These effects are demonstrated with holomyoglobin ions to illustrate that the metal ion reduction takes place without detectable protein denaturation, which might be revealed by heme loss or an increase in charge state distribution. No evidence is observed for denaturation with exposure to any of the organic vapors evaluated in this work.

  14. Effects of metal-ion replacement on pyrazinamidase activity: A quantum mechanical study.

    Science.gov (United States)

    Khadem-Maaref, Mahmoud; Mehrnejad, Faramarz; Phirouznia, Arash

    2017-05-01

    Pyrazinamidase (PZase), a metalloenzyme, is responsible for acidic modification of pyrazinamide (PZA), a drug used in tuberculosis treatment. The metal coordination site of the enzyme is able to coordinate various divalent metal cofactors. Previous experimental studies have demonstrated that metal ions, such as Co 2+ , Mn 2+ , and Zn 2+ , are able to reactivate metal-depleted PZase, while others including Cu 2+ , Fe 2+ , and Mg 2+ , cannot restore activity. In this study, we investigated binding of various metal ions to the metal coordination site (MCS) of the enzyme using quantum mechanical calculations. We calculated the metal-ligand (residue) binding energy and the atomic partial charges in the presence of various ions. The results indicated that the tendency of alkaline earth metals to bind to PZase MCS is very low and not suitable for enzyme structural and catalytic function. In contrast, Co 2+ and Ni 2+ ions have very high binding affinity and are favorable to the structural and functional properties of the enzyme. Furthermore, we observed that the rate at which Ni 2+ , Co 2+ and Fe 2+ ions in PZase MCS polarize the OH bond of coordinated water molecules is much higher than the polarization rate created by other ions. This finding suggests that the coordination of Ni 2+ , Co 2+ , or Fe 2+ to PZase facilitates the deprotonation of coordinated water molecules to generate a nucleophile that catalyzes the enzymatic reaction. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Long range implantation by MEVVA metal ion source

    International Nuclear Information System (INIS)

    Zhang Tonghe; Wu Yuguang; Ma Furong; Liang Hong

    2001-01-01

    Metal vapor vacuum arc (MEVVA) source ion implantation is a new technology used for achieving long range ion implantation. It is very important for research and application of the ion beam modification of materials. The results show that the implanted atom diffusion coefficient increases in Mo implanted Al with high ion flux and high dose. The implanted depth is 311.6 times greater than that of the corresponding ion range. The ion species, doses and ion fluxes play an important part in the long-range implantation. Especially, thermal atom chemistry have specific effect on the long-range implantation during high ion flux implantation at transient high target temperature

  16. Ion irradiation effect on metallic condensate adhesion to glass

    International Nuclear Information System (INIS)

    Kovalenko, V.V.; Upit, G.P.

    1984-01-01

    The ion irradiation effect on metallic condensate adhesion to glass is investigated. It has been found that in case of indium ion deposition the condensate adhesion to glass cleavages being in contact with atmosphere grows up to the level corresponding to a juvenile surface while in case of argon ion irradiation - exceeds it. It is shown that the observed adhesion growth is determined mainly by the surfwce modification comparising charge accumulation on surface, destruction of a subsurface layer and an interlayer formation in the condensate-substrate interface. The role of these factors in the course of various metals deposition is considered

  17. A computational study of adsorption of divalent metal ions on graphene oxide

    Directory of Open Access Journals (Sweden)

    Somphob Thompho

    2017-12-01

    Full Text Available Adsorption of divalent metal ions (Pb2+,Cd2+, Zn2+,Cu2+ on graphene oxide (GO was studied using density functional theory (DFT. Adsorption geometries and energies, as well as the nature of the binding energy, were calculated for the interaction of divalent metal ions with oxygen-containing groups on the surface of GO. The configurations of the complexes were modeled by placing the divalent metal ions above the center and perpendicular to the surface. Binding of Cu2+ to the GO sheet was predicted to be much stronger than that for other divalent metal ions. Calculated results show good agreement with experimental observations and provide useful information for environmental pollution cleanup.

  18. Facile synthesis of Fe3O4@PDA core-shell microspheres functionalized with various metal ions: A systematic comparison of commonly-used metal ions for IMAC enrichment.

    Science.gov (United States)

    Jiang, Jiebing; Sun, Xueni; Li, Yan; Deng, Chunhui; Duan, Gengli

    2018-02-01

    Metal ions differed greatly in affinity towards phosphopeptides, and thus it is essential to systematically compare the phosphopeptides enrichment ability of different metal ions usually used in the IMAC techniques. In this work, for the first time, eight metal ions, including Nb 5+ , Ti 4+ , Zr 4+ , Ga 3+ , Y 3+ , In 3+ , Ce 4+ , Fe 3+ , were immobilized on the polydopamine (PDA)-coated Fe 3 O 4 (denoted as Fe 3 O 4 @PDA-M n+ ), and systematically compared by the real biosamples, in addition to standard phosphopeptides. Fe 3 O 4 microspheres were synthesized via the solvothermal reaction, followed by self-polymerization of dopamine on the surface. Then through taking advantage of the hydroxyl and amino group of PDA, the eight metal ions were easily adhered to the surface of Fe 3 O 4 @PDA. After characterization, the resultant Fe 3 O 4 @PDA-M n+ microspheres were applied to phosphopeptides enrichment based on the binding affinity between metal ions and phosphopeptides. According to the results, different metal ions presented diverse phosphopeptides enrichment efficiency in terms of selectivity, sensitivity and the enrichment ability from real complex samples, and Fe 3 O 4 @PDA-Nb 5+ and Fe 3 O 4 @PDA-Ti 4+ showed obvious advantages of the phosphopeptides enrichment effect after the comparison. This systematic comparison may provide certain reference for the use and development of IMAC materials in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Novel modified poly vinyl chloride blend membranes for removal of heavy metals from mixed ion feed sample

    Energy Technology Data Exchange (ETDEWEB)

    Nayak, Vignesh; Jyothi, M.S. [Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Kanakapura Ramanagaram, Bangalore, 562112 (India); Balakrishna, R. Geetha, E-mail: br.geetha@jainuniversity.ac.in [Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Kanakapura Ramanagaram, Bangalore, 562112 (India); Padaki, Mahesh, E-mail: sp.mahesh@jainuniversity.ac.in [Centre for Nano and Material Sciences, Jain University, Jain Global Campus, Kanakapura Ramanagaram, Bangalore, 562112 (India); National University of Science and Technology “MISIS”, Moscow, 119049 (Russian Federation); Deon, Sebastien [Institut UTINAM, UMR CNRS 6213, Université de Bourgogne-Franche-Comté,16 route de Gray, Besançon Cedex 25030 (France)

    2017-06-05

    Highlights: • Work reports the novel modification of poly vinyl chloride (PVC) using newly developed method. • Blend membranes were prepared using modified PVC and polysulfone in different compositions. • The prepared blend membranes were used for separation of different heavy metal ions. • The blend membranes showed improved rejection of heavy metal ions in comparison to Commercial NF 270 membrane. - Abstract: Herein, an attempt has been made to prepare a novel membrane with good efficiency for removal of heavy metal ions namely lead (Pb), cadmium (Cd) and chromium (Cr). 4-amino benzoic acid (ABA) was covalently grafted onto the poly vinyl chloride (PVC) backbone by C−N bond to enhance the hydrophilicity. {sup 1}H NMR and ATR-IR spectroscopy analysis confirmed the chemical modification of PVC. Further the modified polymer was blended in different compositions with polysulfone (PSf) for optimization. Morphological changes that occurred in blend membranes, due to the incorporation of modified PVC was studied by AFM and SEM techniques. The effect on hydrophilicity and performance of blends owing to incorporation of modified PVC was evaluated by water uptake, contact angle and flux studies. The density of functional groups in blends was analyzed by its ion-exchange capacity. Batch wise filtration of metal ions was carried out and the effect of pressure, feed pH and interference of ions was thoroughly investigated. Essentially, 100% rejection was obtained for all the metal ions in acidic pH with a productivity of 2.56 l/m{sup 2} h. The results were correlated with the results of commercially available NF 270 membrane under the same operating conditions.

  20. Novel modified poly vinyl chloride blend membranes for removal of heavy metals from mixed ion feed sample

    International Nuclear Information System (INIS)

    Nayak, Vignesh; Jyothi, M.S.; Balakrishna, R. Geetha; Padaki, Mahesh; Deon, Sebastien

    2017-01-01

    Highlights: • Work reports the novel modification of poly vinyl chloride (PVC) using newly developed method. • Blend membranes were prepared using modified PVC and polysulfone in different compositions. • The prepared blend membranes were used for separation of different heavy metal ions. • The blend membranes showed improved rejection of heavy metal ions in comparison to Commercial NF 270 membrane. - Abstract: Herein, an attempt has been made to prepare a novel membrane with good efficiency for removal of heavy metal ions namely lead (Pb), cadmium (Cd) and chromium (Cr). 4-amino benzoic acid (ABA) was covalently grafted onto the poly vinyl chloride (PVC) backbone by C−N bond to enhance the hydrophilicity. 1 H NMR and ATR-IR spectroscopy analysis confirmed the chemical modification of PVC. Further the modified polymer was blended in different compositions with polysulfone (PSf) for optimization. Morphological changes that occurred in blend membranes, due to the incorporation of modified PVC was studied by AFM and SEM techniques. The effect on hydrophilicity and performance of blends owing to incorporation of modified PVC was evaluated by water uptake, contact angle and flux studies. The density of functional groups in blends was analyzed by its ion-exchange capacity. Batch wise filtration of metal ions was carried out and the effect of pressure, feed pH and interference of ions was thoroughly investigated. Essentially, 100% rejection was obtained for all the metal ions in acidic pH with a productivity of 2.56 l/m 2 h. The results were correlated with the results of commercially available NF 270 membrane under the same operating conditions.

  1. Investigation of metal ions sorption of brown peat moss powder

    Science.gov (United States)

    Kelus, Nadezhda; Blokhina, Elena; Novikov, Dmitry; Novikova, Yaroslavna; Chuchalin, Vladimir

    2017-11-01

    For regularities research of sorptive extraction of heavy metal ions by cellulose and its derivates from aquatic solution of electrolytes it is necessary to find possible mechanism of sorption process and to choice a model describing this process. The present article investigates the regularities of aliovalent metals sorption on brown peat moss powder. The results show that sorption isotherm of Al3+ ions is described by Freundlich isotherm and sorption isotherms of Na+ i Ni2+ are described by Langmuir isotherm. To identify the mechanisms of brown peat moss powder sorption the IR-spectra of the initial brown peat moss powder samples and brown peat moss powder samples after Ni (II) sorption were studied. Metal ion binding mechanisms by brown peat moss powder points to ion exchange, physical adsorption, and complex formation with hydroxyl and carboxyl groups.

  2. Acetabular bone density and metal ions after metal-on-metal versus metal-on-polyethylene total hip arthroplasty; short-term results

    NARCIS (Netherlands)

    Zijlstra, Wierd P.; van der Veen, Hugo C.; van den Akker-Scheek, Inge; Zee, Mark J. M.; Bulstra, Sjoerd K.; van Raay, Jos J. A. M.

    Information on periprosthetic acetabular bone density is lacking for metal-on-metal total hip arthroplasties. These bearings use cobalt-chromium instead of titanium acetabular components, which could lead to stress shielding and hence periprosthetic bone loss. Cobalt and chromium ions have

  3. Selective transport and incorporation of highly charged metal and metal complex ions in self-assembled polyelectrolyte multilayer membranes

    International Nuclear Information System (INIS)

    Toutianoush, Ali; Tieke, Bernd

    2002-01-01

    The transport of aqueous salts containing mono-, di- and trivalent metal and tetravalent metal complex ions across ultrathin polyvinylammonium/polyvinylsulphate (PVA/PVS) membranes is described. The membranes were prepared by electrostatic layer-by-layer (LBL) assembly of the two polyelectrolytes. Using spectroscopic measurements and permeability studies, it is demonstrated that the transport of copper(II) chloride, lanthanum(III) chloride, barium chloride and potassium hexacyanoferrate(II) is accompanied by the permanent incorporation of the metal and metal complex ions in the membrane. Upon the uptake of copper, lanthanum and hexacyanoferrate ions, the membranes become cross-linked so that the permeation rates of other salts not taken up by the membrane, e.g. sodium chloride, potassium chloride and magnesium chloride, are decreased. The uptake of barium ions leads to a decrease of the cross-linking density of the membrane so that the permeation rate of NaCl is increased. Possible mechanisms for the ion uptake are discussed

  4. Interaction of d(10) metal ions with thioether ligands: a thermodynamic and theoretical study.

    Science.gov (United States)

    Melchior, Andrea; Peralta, Elena; Valiente, Manuel; Tavagnacco, Claudio; Endrizzi, Francesco; Tolazzi, Marilena

    2013-05-07

    Thermodynamic parameters of complex formation between d(10) metal ions, such as Zn(2+), Cd(2+), Hg(2+) and Ag(+), and the macrocyclic thioether 1,4,7-trithiacyclononane ([9]AneS3) or the monodentate diethylsulfide (Et(2)S), in acetonitrile (AN) at 298.15 K, were studied by a systematic methodology including potentiometry, calorimetry and polarography. [9]AneS3 is able to form complexes with all the target cations, Et(2)S only reacts with Hg(2+) and Ag(+). Mononuclear ML(j) (j = 1, 2) complexes are formed with all the metal ions investigated, where the affinity order is Hg(2+) > Ag(+) > Cd(2+) ≈ Zn(2+) when L = [9]AneS3 and Hg(2+) > Ag(+) when L = Et(2)S. Enthalpy and entropy values are generally negative, as a consequence of both metal ion interactions with neutral ligands, the reagents' loss of degrees of freedom and the release of solvating molecules. DFT calculations on the complexes formed with [9]AneS3 in vacuum and in AN are also carried out, to correlate experimental and theoretical thermodynamic values and to highlight the interplay between the direct metal-thioether interaction and the solvation effects. Trends obtained for the stability constants and enthalpies of the 1 : 1 and 1 : 2 complexes in solvent well reproduce the experimental ones for all the divalent metal ion complexes with [9]AneS3 and indicate the release of 3 AN molecules in the formation of each consecutive octahedral complex. In addition, calculated and experimental values for Ag(+) complex formation in solution suggest that in AgL(2) species [9]AneS3 ligands are not both tridentate.

  5. Accelerated electron exchange between U4+ and UO22+ by foreign metal ions

    International Nuclear Information System (INIS)

    Obanawa, Heiichiro; Onitsuka, Hatsuki; Takeda, Kunihiko

    1990-01-01

    The rate constant of U 4+ -UO 2 2+ electron exchange (k et ) was increased by more than 100 times in the presence of various metal ions. The larger rate constant was observed for the smaller difference of the standard reduction potential strength between metal ion and UO 2 2+ ion (Δμ θ e ). Detailed investigation of the electron exchange reaction in the presence of Mo 5+ suggested that the mechanism of the electron transfer reaction catalyzed by metal ions is the outer-sphere type independent of U-Clcomplex ions. (author)

  6. The solvent extraction of alkali metal ions with β-diketones

    International Nuclear Information System (INIS)

    Munakata, Megumu; Niina, Syozo; Shimoji, Noboru

    1974-01-01

    This work was undertaken to investigate effects of solvent and chelating-agent on the solvent extraction of alkali metal ions by seven β-diketones, acetylacetone (Acac), benzoylacetone (BzA), dipivaloylmethane (DPM), dibenzoylmethane (DBM), thenoyltrifluoloacetone (TTA), benzoyltrifluoroacetone (BFA) and hexafluoroacetylacetone (HFA), and to separate lithium from alkali metals. The extraction of alkali metals increase with increasing donor power of the solvent: i.e., benzene Na>K>Rb>Cs, which is also the order in which the adduct formation of these β-diketone chelates with donor solvents increase. The adduct formations between β-diketone chelates of alkali metals and donor solvents markedly enhance the solubilities of the chelates in solvents and, consequently, the extractabilities of alkali metals with β-diketones. Lithium was extracted with TTA in ether at such a low base concentration that sodium, potassium, rubidium and cesium were hardly extracted, and this enabled to separate lithium from other metals by the use of rubidium hydroxide (0.02 M). An attempt has been made to isolate alkali metal β-diketone chelates and some chelates have been obtained as crystals. The infrared absorption bands arising from C=O and C.=C of TTA shift to lower frequencies in the alkali metal chelates with TTA, and consequently, β-diketones is suggested to coordinate to alkali metal as a bidentate ligand. (JPN)

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

    International Nuclear Information System (INIS)

    Fish, D.

    1996-01-01

    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

  8. Some aspects of metallic ion chemistry and dynamics in the mesosphere and thermosphere

    Science.gov (United States)

    Mathews, J. D.

    1987-01-01

    The relationship between the formation of sporadic layers of metallic ion and the dumping of these ions into the upper mesosphere is discussed in terms of the tidal wind, classical (i.e., windshear) and other more complex, perhaps highly nonlinear layer formation mechanisms, and a possible circulation mechanism for these ions. Optical, incoherent scatter radar, rocket, and satellite derived evidence for various layer formation mechanisms and for the metallic ion circulation system is reviewed. The results of simple one dimensional numerical model calculations of sporadic E and intermediate layer formation are presented along with suggestions for more advanced models of intense or blanketing sporadic E. The flux of metallic ions dumped by the tidal wind system into the mesosphere is estimated and compared with estimates of total particle flux of meteoric origin. Possible effects of the metallic ion flux and of meteoric dust on D region ion chemistry are discussed.

  9. Ranges of ions in metals for use in particle treatment planning

    International Nuclear Information System (INIS)

    Jaekel, Oliver

    2006-01-01

    In proton and ion radiotherapy, the range of particles is calculated from x-ray computed tomography (CT) numbers. Due to the strong absorption of x-rays in a metal and a cut-off for large Hounsfield units (HU) in the software of most CT-scanners, a range calculation in metals cannot be based on the measured HU. This is of special importance when metal implants such as gold fillings or hip prostheses are close to the treatment volume. In order to overcome this problem in treatment planning for heavy charged particles, the correct ranges of ions in the metal relative to water have to be assigned in the CT data. Measurements and calculations of carbon ion ranges in various metals are presented that can be used in treatment planning to allow for a more accurate range calculation of carbon ion beams in titanium, steel, tungsten and gold. The suggested values for the relative water-equivalent range and their uncertainties are 3.13 (±3%) for titanium, 5.59 (±3%) for stainless steel and 10.25 (±4%) for gold. (note)

  10. Sensing of heavy metal ions by intrinsic TMV coat protein fluorescence

    Science.gov (United States)

    Bayram, Serene S.; Green, Philippe; Blum, Amy Szuchmacher

    2018-04-01

    We propose the use of a cysteine mutant of TMV coat protein as a signal transducer for the selective sensing and quantification of the heavy metal ions, Cd2+, Pb2+, Zn2+ and Ni2+ based on intrinsic tryptophan quenching. TMV coat protein is inexpensive, can be mass-produced since it is expressed and extracted from E-coli. It also displays several different functional groups, enabling a wide repertoire of bioconjugation chemistries; thus it can be easily integrated into functional devices. In addition, TMV-ion interactions have been widely reported and utilized for metallization to generate organic-inorganic hybrid composite novel materials. Building on these previous observations, we herein determine, for the first time, the TMV-ion binding constants assuming the static fluorescence quenching model. We also show that by comparing TMV-ion interactions between native and denatured coat protein, we can distinguish between chemically similar heavy metal ions such as cadmium and zinc ions.

  11. Smart responsive microcapsules capable of recognizing heavy metal ions.

    Science.gov (United States)

    Pi, Shuo-Wei; Ju, Xiao-Jie; Wu, Han-Guang; Xie, Rui; Chu, Liang-Yin

    2010-09-15

    Smart responsive microcapsules capable of recognizing heavy metal ions are successfully prepared with oil-in-water-in-oil double emulsions as templates for polymerization in this study. The microcapsules are featured with thin poly(N-isopropylacrylamide-co-benzo-18-crown-6-acrylamide) (P(NIPAM-co-BCAm)) membranes, and they can selectively recognize special heavy metal ions such as barium(II) or lead(II) ions very well due to the "host-guest" complexation between the BCAm receptors and barium(II) or lead(II) ions. The stable BCAm/Ba(2+) or BCAm/Pb(2+) complexes in the P(NIPAM-co-BCAm) membrane cause a positive shift of the volume phase transition temperature of the crosslinked P(NIPAM-co-BCAm) hydrogel to a higher temperature, and the repulsion among the charged BCAm/Ba(2+) or BCAm/Pb(2+) complexes and the osmotic pressure within the P(NIPAM-co-BCAm) membranes result in the swelling of microcapsules. Induced by recognizing barium(II) or lead(II) ions, the prepared microcapsules with P(NIPAM-co-BCAm) membranes exhibit isothermal and significant swelling not only in outer and inner diameters but also in the membrane thickness. The proposed microcapsules in this study are highly attractive for developing smart sensors and/or carriers for detection and/or elimination of heavy metal ions. Copyright 2010 Elsevier Inc. All rights reserved.

  12. Whiskers growth and self-healing in Ti-based metallic glasses during ion irradiation

    Science.gov (United States)

    Zhang, Kun; Hu, Zheng; Zhao, Ziqiang; Wei, Bingchen; Li, Yansen; Wei, Yuhang

    2018-04-01

    Ti-based metallic glasses were subjected to a 20 MeV Cl4+ ion radiation under liquid-nitrogen cooling. Their responses, as well as effects of the electronic excitation and nucleus-nucleus collision were evaluated. The collision cascade during irradiation typically changes the structure by increasing the liquid-like zone/cluster, or the content of the free volume. However, along the ion incident depth, the structure change is inhomogeneous. Numerous whiskers appear and aggregate on the side of the irradiation surface, which are several micrometers away from the edge. This corresponds with the maximum collision depth obtained by the Monte Carlo simulation, where nuclear loss plays a dominant role. Moreover, the liquid-like zone continually forms, which add to the whiskers growth and subsequent self-healing. Results suggest that the irradiation-induced local shear stress combines with the well-localized liquid-like zone results in the observed phenomena. This study demonstrates that metallic glasses have high morphological instability under ion irradiation, which assets can pave new paths for their further applications.

  13. Determination of the total concentration and speciation of metal ions in river, estuarine and seawater samples.

    Science.gov (United States)

    Alberti, Giancarla; Biesuz, Raffaela; Pesavento, Maria

    2008-12-01

    Different natural water samples were investigated to determine the total concentration and the distribution of species for Cu(II), Pb(II), Al(III) and U(VI). The proposed method, named resin titration (RT), was developed in our laboratory to investigate the distribution of species for metal ions in complex matrices. It is a competition method, in which a complexing resin competes with natural ligands present in the sample to combine with the metal ions. In the present paper, river, estuarine and seawater samples, collected during a cruise in Adriatic Sea, were investigated. For each sample, two RTs were performed, using different complexing resins: the iminodiacetic Chelex 100 and the carboxylic Amberlite CG50. In this way, it was possible to detect different class of ligands. Satisfactory results have been obtained and are commented on critically. They were summarized by principal component analysis (PCA) and the correlations with physicochemical parameters allowed one to follow the evolution of the metals along the considered transect. It should be pointed out that, according to our findings, the ligands responsible for metal ions complexation are not the major components of the water system, since they form considerably weaker complexes.

  14. Do soft drinks affect metal ions release from orthodontic appliances?

    Science.gov (United States)

    Mikulewicz, Marcin; Wołowiec, Paulina; Loster, Bartłomiej W; Chojnacka, Katarzyna

    2015-01-01

    The effect of orange juice and Coca Cola(®) on the release of metal ions from fixed orthodontic appliances. A continuous flow system designed for in vitro testing of orthodontic appliances was used. Orange juice/Coca Cola(®) was flowing through the system alternately with artificial saliva for 5.5 and 18.5h, respectively. The collected samples underwent a multielemental ICP-OES analysis in order to determine the metal ions release pattern in time. The total mass of ions released from the appliance into orange juice and Coca Cola(®) (respectively) during the experiment was calculated (μg): Ni (15.33; 37.75), Cr (3.604; 1.052), Fe (48.42; ≥ 156.1), Cu (57.87, 32.91), Mn (9.164; 41.16), Mo (9.999; 30.12), and Cd (0.5967; 2.173). It was found that orange juice did not intensify the release of metal ions from orthodontic appliances, whereas Coca Cola(®) caused increased release of Ni ions. Copyright © 2015 Elsevier GmbH. All rights reserved.

  15. Effects of metal ions on the catalytic degradation of dicofol by cellulase.

    Science.gov (United States)

    Zhai, Zihan; Yang, Ting; Zhang, Boya; Zhang, Jianbo

    2015-07-01

    A new technique whereby cellulase immobilized on aminated silica was applied to catalyze the degradation of dicofol, an organochlorine pesticide. In order to evaluate the performance of free and immobilized cellulase, experiments were carried out to measure the degradation efficiency. The Michaelis constant, Km, of the reaction catalyzed by immobilized cellulase was 9.16 mg/L, and the maximum reaction rate, Vmax, was 0.40 mg/L/min, while that of free cellulase was Km=8.18 mg/L, and Vmax=0.79 mg/L/min, respectively. The kinetic constants of catalytic degradation were calculated to estimate substrate affinity. Considering that metal ions may affect enzyme activity, the effects of different metal ions on the catalytic degradation efficiency were explored. The results showed that the substrate affinity decreased after immobilization. Monovalent metal ions had no effect on the reaction, while divalent metal ions had either positive or inhibitory effects, including activation by Mn2+, reversible competition with Cd2+, and irreversible inhibition by Pb2+. Ca2+ promoted the catalytic degradation of dicofol at low concentrations, but inhibited it at high concentrations. Compared with free cellulase, immobilized cellulase was affected less by metal ions. This work provided a basis for further studies on the co-occurrence of endocrine-disrupting chemicals and heavy metal ions in the environment. Copyright © 2015. Published by Elsevier B.V.

  16. Elaboration and test of the method of separation of alkaline metals ions with tin phosphate

    International Nuclear Information System (INIS)

    Smirnov, G.I.; Chernyak, A.S.; Kostromina, O.N.; Kachur, N.Ya.; Shpeyzer, B.G.

    1986-01-01

    Present work is devoted to elaboration and test of the method of separation of alkaline metals ions with tin phosphate. Thus, the isotherms of sorption of lithium, sodium, potassium, rubidium and cesium ions with amorphous tin phosphate depending on their concentration, ph of solution, sorbent quantity are obtained. The parameters of extraction of potassium microquantities from sodium salts are defined. Ultra pure sodium chloride, sodium iodide, sodium sulphate, sodium nitrate, sodium nitrite, sodium phosphate are synthesized.

  17. Application of Sargassum biomass to remove heavy metal ions from synthetic multi-metal solutions and urban storm water runoff.

    Science.gov (United States)

    Vijayaraghavan, K; Teo, Ting Ting; Balasubramanian, R; Joshi, Umid Man

    2009-05-30

    The ability of Sargassum sp. to biosorb four metal ions, namely lead, copper, zinc, and manganese from a synthetic multi-solute system and real storm water runoff has been investigated for the first time. Experiments on synthetic multi-solute systems revealed that Sargassum performed well in the biosorption of all four metal ions, with preference towards Pb, followed by Cu, Zn, and Mn. The solution pH strongly affected the metal biosorption, with pH 6 being identified as the optimal condition for achieving maximum biosorption. Experiments at different biosorbent dosages revealed that good biosorption capacity as well as high metal removal efficiency was observed at 3g/L. The biosorption kinetics was found to be fast with equilibrium being attained within 50 min. According to the Langmuir isotherm model, Sargassum exhibited maximum uptakes of 214, 67.5, 24.2 and 20.2mg/g for lead, copper, zinc, and manganese, respectively in single-solute systems. In multi-metal systems, strong competition between four metal ions in terms of occupancy binding sites was observed, and Sargassum showed preference in the order of Pb>Cu>Zn>Mn. The application of Sargassum to remove four heavy metal ions in real storm water runoff revealed that the biomass was capable of removing the heavy metal ions. However, the biosorption performance was slightly lower compared to that of synthetic metal solutions. Several factors were responsible for this difference, and the most important factor is the presence of other contaminants such as anions, organics, and other trace metals in the runoff.

  18. Ion-induced electron emission from clean metals

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Alonso, E.V.; Ferron, J.; Oliva-Florio, A.; Universidad Nacional de Cuyo, San Carlos de Bariloche

    1979-01-01

    We report recent experimental work on electron emission from clean polycrystalline metal surfaces under ion bombardment. We critically discuss existing theories and point out the presently unsolved problems. (orig.)

  19. Adsorption of metal ions and acid dyes on brewer's refuse and its crosslinked products; Biru shikomikasu oyobi sono kashikaketai ni taisuru kinzoku ion oyobi sansei senryo no kyuchaku

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Y.; Kubota, Y.; Higashimura, T. [The University of Shiga Prefecture, Shiga (Japan). Department of Materials Sceince; Kawaguchi, M. [Seisui Kogyo Ltd., Osaka (Japan)

    2000-01-10

    To use brewer's refuse as adsorbent adsorption of metal ions and acid dyes on them and their reaction products with 1,3,5-triacryloylhexahydro-1,3,5-triazine(TAF) were examined. The refuse samples used in the present study are protein rich fraction(Pr) and cellulosics rich fraction(Hr) obtained by sifting brewer's refuse. Adsorptive experiments were conducted by a batchwise method at 303 K. Pr adsorbed more metal ions such as Cr{sup 6+}, Ni{sup 2+}, Co{sup 2+}, especially Fe{sup 3+}, Hg{sup 2+} and Cu{sup 2+} than Hr. But both refuses hardly adsorbed Ca{sup 2+}. Also Pr adsorbed more acid dyes, especially more hydrophobic C. I. Acid Red 88 than C. I. Acid Orange 7- than Hr at pH 5. By crosslinking Pr and Hr using TAF adsorption of acid dyes increased markedly, but adsorption of metal ions decreased. Therefore Pr can be used as adsorbent for acid dyes and metal ions as it is. Moreover the crosslinked products are excellent adsorbents for acid dyes. (author)

  20. Ionic liquids used in extraction and separation of metal ions

    International Nuclear Information System (INIS)

    Shen Xinghai; Xu Chao; Liu Xinqi; Chu Taiwei

    2006-01-01

    Ionic liquids as green solvents now have become a research hotspot in the field of separation of metal ions by solvent extraction. Experimental results of extraction of various metal ions with ionic liquids as solvents, including that of alkali metals, alkaline earths, transition metals rare earths and actinides are introduced. The extraction of uranium, plutonium and fission products that are involved in spent nuclear fuel reprocessing is also reviewed. The possible extraction mechanisms are discussed. Finally, the prospect of replacement of volatile and/or toxic organic solvents with environmentally benign ionic liquids for solvent extraction and the potency of applications of ionic liquids in solvent extraction are also commented. (authors)

  1. Cleavage reactions of the complex ions derived from self-complementary deoxydinucleotides and alkali-metal ions using positive ion electrospray ionization with tandem mass spectrometry.

    Science.gov (United States)

    Xiang, Yun; Abliz, Zeper; Takayama, Mitsuo

    2004-05-01

    The dissociation reactions of the adduct ions derived from the four self-complementary deoxydinucleotides, d(ApT), d(TpA), d(CpG), d(GpC), and alkali-metal ions were studied in detail by positive ion electrospray ionization multiple-stage mass spectrometry (ESI-MS(n)). For the [M + H](+) ions of the four deoxydinucleotides, elimination of 5'-terminus base or loss of both of 5'-terminus base and a deoxyribose were the major dissociation pathway. The ESI-MS(n) spectra showed that Li(+), Na(+), and Cs(+) bind to deoxydinucleotides mainly by substituting the H(+) of phosphate group, and these alkali-metal ions preferred to bind to pyrimidine bases rather than purine bases. For a given deoxydinucleotide, the dissociation pathway of [M + K](+) ions differed clearly from that of [M + Li](+), [M + Na](+), and [M + Cs](+) ions. Some interesting and characteristic cleavage reactions were observed in the product-ion spectra of [M + K](+) ions, including direct elimination of deoxyribose and HPO(3) from molecular ions. The fragmentation behavior of the [M + K](+) and [M + W](+) (W = Li, Na, Cs) adduct ions depend upon the sequence of bases, the interaction between alkali-metal ions and nucleobases, and the steric hindrance caused by bases.

  2. Damage induced by helium ion irradiation in Fe-based metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaonan; Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn; Zhang, Qi; Li, Xiaona; Qiang, Jianbing; Wang, Younian

    2017-07-15

    The changes in structure and surface morphology of metallic glasses Fe{sub 80}Si{sub 7.43}B{sub 12.57} and Fe{sub 68}Zr{sub 7}B{sub 25} before and after the irradiation of He ions with the energy of 300 keV were investigated, and were compared with that of the tungsten. The results show that after the He{sup 2+} irradiation, metallic glass Fe{sub 68}Zr{sub 7}B{sub 25} still maintained amorphous. While a small amount of metastable β-Mn type phase nanocrystals formed in metallic glass Fe{sub 80}Si{sub 7.43}B{sub 12.57} at the fluence of 4.0 × 10{sup 17}ions/cm{sup 2} (19dpa). The nanocrystals transformed into α-Fe phase and tetragonal Fe{sub 2}B phase as the fluence increased to 1.0 × 10{sup 18}ions/cm{sup 2} (47dpa). Then the new orthogonal Fe{sub 3}B phase and β-Mn type phase nanocrystals appeared when the fluence increased further, and the quantities of nanocrystals increased. Blisters and cracks appeared on the surface of tungsten under the irradiation fluence of 1.0 × 10{sup 18}ions/cm{sup 2}, however only when the fluence was up to 1.6 × 10{sup 18}ions/cm{sup 2}, could cracks and spalling appear on the surfaces of metallic glasses. - Highlights: •Metallic glass Fe{sub 68}Zr{sub 7}B{sub 25} could maintain amorphous state after the irradiation. •A series of crystallization behaviors occurred in metallic glass Fe{sub 80}Si{sub 7.43}B{sub 12.57}. •The surface of tungsten appeared blisters at the fluence of 1.0 × 10{sup 18} ions/cm{sup 2}. •Surfaces of Fe-based metallic glasses cracked at the fluence of 1.6 × 10{sup 18}ions/cm{sup 2}.

  3. The fabrication of metal silicide nanodot arrays using localized ion implantation

    International Nuclear Information System (INIS)

    Han, Jin; Kim, Tae-Gon; Min, Byung-Kwon; Lee, Sang Jo

    2010-01-01

    We propose a process for fabricating nanodot arrays with a pitch size of less than 25 nm. The process consists of localized ion implantation in a metal thin film on a Si wafer using a focused ion beam (FIB), followed by chemical etching. This process utilizes the etching resistivity changes of the ion beam irradiated region that result from metal silicide formation by ion implantation. To control the nanodot diameter, a threshold ion dose model is proposed using the Gaussian distribution of the ion beam intensities. The process is verified by fabricating nanodots with various diameters. The mechanism of etching resistivity is investigated via x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES).

  4. Heavy metal ion adsorption behavior in nitrogen-doped magnetic carbon nanoparticles: Isotherms and kinetic study

    International Nuclear Information System (INIS)

    Shin, Keun-Young; Hong, Jin-Yong; Jang, Jyongsik

    2011-01-01

    Graphical abstract: Display Omitted Research highlights: → The monodisperse and multigram-scale N-MCNPs are fabricated by carbonization of polypyrrole as a carbon precursor. → The synthesized N-MCNPs provide an enhanced adsorption uptake for various heavy metal ions. → The N-MCNPs can be applied to the Langmuir model and pseudo-second-order kinetics. → The iron-impregnated N-MCNPs are reused up to 5 times with no loss of removal efficiency. - Abstract: To clarify the heavy metal adsorption mechanism of nitrogen-doped magnetic carbon nanoparticles (N-MCNPs), adsorption capacity was investigated from the adsorption isotherms, kinetics and thermodynamics points of view. The obtained results showed that the equilibrium adsorption behavior of Cr 3+ ion onto the N-MCNPs can be applied to the Langmuir model and pseudo-second-order kinetics. It indicated that the fabricated N-MCNPs had the homogenous surface for adsorption and all adsorption sites had equal adsorption energies. Furthermore, the adsorption onto N-MCNPs taken place through a chemical process involving the valence forces. According to the thermodynamics, the adsorption process is spontaneous and endothermic in nature which means that the adsorption capacity increases with increasing temperature due to the enhanced mobility of adsorbate molecules. The effects of the solution pH and the species of heavy metal ion on the adsorption uptake were also studied. The synthesized N-MCNPs exhibited an enhanced adsorption capacity for the heavy metal ions due to the high surface area and large amount of nitrogen contents.

  5. Theoretical investigation of the use of nanocages with an adsorbed halogen atom as anode materials in metal-ion batteries.

    Science.gov (United States)

    Razavi, Razieh; Abrishamifar, Seyyed Milad; Rajaei, Gholamreza Ebrahimzadeh; Kahkha, Mohammad Reza Rezaei; Najafi, Meysam

    2018-02-21

    The applicability of C 44 , B 22 N 22 , Ge 44 , and Al 22 P 22 nanocages, as well as variants of those nanocages with an adsorbed halogen atom, as high-performance anode materials in Li-ion, Na-ion, and K-ion batteries was investigated theoretically via density functional theory. The results obtained indicate that, among the nanocages with no adsorbed halogen atom, Al 22 P 22 would be the best candidate for a novel anode material for use in metal-ion batteries. Calculations also suggest that K-ion batteries which utilize these nanocages as anode materials would give better performance and would yield higher cell voltages than the corresponding Li-ion and Na-ion batteries with nanocage-based anodes. Also, the results for the nanocages with an adsorbed halogen atom imply that employing them as anode materials would lead to higher cell voltages and better metal-ion battery performance than if the nanocages with no adsorbed halogen atom were to be used as anode materials instead. Results further implied that nanocages with an adsorbed F atom would give higher cell voltages and better battery performance than nanocages with an adsorbed Cl or Br atom. We were ultimately able to conclude that a K-ion battery that utilized Al 21 P 22 with an adsorbed F atom as its anode material would afford the best metal-ion battery performance; we therefore propose this as a novel highly efficient metal-ion battery. Graphical abstract The results of a theoretical investigation indicated that Al 22 P 22 is a better candidate for a high-performance anode material in metal-ion batteries than Ge 44 is. Calculations also showed that K-ion batteries with nanocage-based anodes would produce higher cell voltages and perform better than the equivalent Li-ion and Na-ion batteries with nanocage-based anodes, and that anodes based on nanocages with an adsorbed F atom would perform better than anodes based on nanocages with an adsorbed Cl or Br atom.

  6. Isotherm studies for determination of removal capacity of bi-metal (Ni and Cr) ions by aspergillus niger

    International Nuclear Information System (INIS)

    Munir, K.; Yusuf, M.; Hameed, A.; Noreen, Z.; Hafeez, F.Y.; Faryal, R.

    2010-01-01

    Pakistan is among the developing countries where there is a need to establish new industries to meet the demands of a growing population. This has led to industrial setup in various sectors, without proper planning and consideration for treatment of contamination, leading to disposal of untreated wastewater into nearby land and water bodies. This study was planned to investigate an indigenous Aspergillus niger for development of biosorbent for the removal of metal ions. The Aspergillus isolate's Ni and Cr removal efficiency was determined in batch mode over various pH (4.0-10.0) and temperature (25-40 deg. C) as single as well as bimetal ions. Using a single metal ion, maximum biosorption potential was obtained at pH 5.0-6.0 and 30-35 deg. C for both ions. On the other hand, Ni removal was reduced in the presence of Cr, while Ni removal influenced Cr removal with an increase showing maximum removal at an initial adsorbate concentration of 50mg/L, pH 6.0 and 35 deg. C. Effect of presence of bimetal in a solution on biosorption potential of Aspergillus niger was predicted by using equilibrium modeling. Adsorption trends for both nickel (R2 0.9916) and chromium (R2 0.8548) followed Langmuir isotherm in single metal removal system, but under bimetal condition chromium adsorption fitted better to Freundlich model and that of nickel followed Temkin isotherm, suggesting considerable change in behavior and interaction between biosorbent and metal ions. Therefore, we concluded that Aspergillus niger a viable strain for development of a biosorbent for removal of a mixture of metal ions. (author)

  7. The sorption of metal ions on nanoscale zero-valent iron

    Directory of Open Access Journals (Sweden)

    Suponik Tomasz

    2017-01-01

    Full Text Available The injection of the colloidal suspensions of nano-iron (nZVI into an aquifer is a novel method of removing metal ions from acidic water. In the batch tests, the equilibrium study of the sorption of metal ions, Cu(II and Zn(II, on Green Tea nanoscale Zero-Valent Ion (GT-nZVI was carried out. The sorption of metal ions on this reactive material was described using the Langmuir, Freundlich and Sips models. This last model described in a better way the sorption equilibrium in the tested range of concentrations and temperature. The value of determination coefficient (R2 for the Sips model, for copper and zinc, was 0.9735 to 0.9995, respectively. GT-nZVI has very good properties in removing Cu(II and Zn(II from acidic water. The high values of qmaxS, the maximum adsorption capacity in the Sips model, amounting to 348.0 and 267.3 mg/g for Cu(II and Zn(II, indicate the high adsorption capacity of GT-nZVI. The analyzed metals have good or very good affinity with GT-nZVI.

  8. Composition and morphology of metal-containing diamond-like carbon films obtained by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Corbella, C.; Pascual, E.; Oncins, G.; Canal, C.; Andujar, J.L.; Bertran, E.

    2005-01-01

    The addition of metal atoms within the matrix of diamond-like carbon films leads to the improvement of their mechanical properties. The present paper discusses the relationship between the composition and morphology of metal-containing (W, Nb, Mo, Ti) diamond-like carbon thin films deposited at room temperature by reactive magnetron sputtering from a metal target in an argon and methane atmosphere. Composition was measured either by electron microprobe technique or by X-ray photoelectron spectroscopy and shows a smooth variation with relative methane flow. High relative methane flows lead to a bulk saturation of carbon atoms, which leads to a lack of homogeneity in the films as confirmed by secondary ion mass spectrometry. Cross-section micrographs were observed by transmission electron microscopy and revealed a structure strongly influenced by the metal inserted and its abundance. The surface pattern obtained by scanning electrochemical potential microscopy provided the metallicity distribution. These measurements were completed with atomic force microscopy of the surface. Selected area electron diffraction and X-ray diffraction measurements provided data of the crystalline structure along with nano-crystallite size. High-resolution transmission electron microscopy provided images of these crystallites

  9. Polymer-supported reagents with enhanced metal ion recognition: Application to separations science

    International Nuclear Information System (INIS)

    Alexandratos, S.D.

    1993-01-01

    The design and development of polymer-supported reagents with ever-increasing specificities for targeted metal ions remains an important areas of research. The need for efficient separation schemes for both ions and molecules has been outlined in a report by the National Research Council (King) and will gain increased emphasis as environmental restoration is pursued. Polymer-supported reagents are unique in their ability to be applied in an environmentally benign manner to a host of challenges. Such reagents, in the form of beads, can be applied to continuous separation processes ranging from the removal of metal ions in water to the recovery of medicinal drugs produced through biotechnological means. The application of polymer-supported reagents to metal ion separations still requires developing a fundamental understanding of ligand-metal interactions, the role of the polymer in those interactions, and the methods of synthesizing such polymeric reagents in a readily applicable form. Ion exchange resins with sulfonic acid ligands are the prototypical polymer-supported reagents, and their properties have been exhaustively studied (Helfferich). The high acidity of the sulfonic acid group, however, precludes much selectivity, and it displays a very limited range of reaction free energy values with different metal ions (Boyd et al.). The carboxylic acid ligand, present in the acrylate resins, is more selective, though its weak acidity requires relatively high pH solutions for it to be effective. Research has thus been focused on the preparation of polymer-supported reagents with high levels of specificity for targeted metal ions

  10. Interaction of Ions with Two-Dimensional Transition Metal Carbide (MXene) Films

    Science.gov (United States)

    Ren, Chang

    Nowadays, society is relying more on nanotechnology for solving critical issues, such as the increasing demand for clean energy and freshwater. Among nanotechnologies, two-dimensional (2D) materials with unique properties are investigated with elevated expectations. In 2011, a new family of 2D materials MXenes were discovered, which became an important addition to the 2D word. The general formula of MXene is Mn+1XnTx, where M stands for transition metal atom, X is C and/or N, n = 1, 2 or 3, and Tx represents surface groups. Nanosheets of MXene obtained by delamination can form flexible films. Additionally, ions can intercalate MXene layers, suggesting potential applications in energy storage and water purification. The Ti3C2Tx MXene films of various thicknesses, which have orderly stacked 2D structure, high density and flexibility, and metallic electrical conductivity of 2400 to 5690 S/cm were fabricated by vacuum-assisted filtration. Ti3C2Tx surface was negatively charged and hydrophilic. Additionally, Ti3C 2Tx films showed sufficient mechanical strength for handling, and the tensile strength of a Ti3C2Tx film was comparable to GO membranes. Metal cations intercalated between the MXene layers, and led to intercalation capacitance. Binder-free Ti3C 2Tx films showed volumetric capacitance of 350 to over 1000 F/cm3 in aqueous electrochemical capacitors (ECs), depending on the electrolyte, and the size of Ti3C2Tx nanosheets. Smaller flakes were obtained by increasing time of ultrasonic treatment. They had a lower electrical conductivity, but a higher capacitance. By introducing polymer nanofillers, such as poly(vinyl alcohol) (PVA) between MXene nanosheets, composite films were prepared and showed controllable electrical conductivity, increased interlayer spacing, improved mechanical strength and capacitive performance. By introducing carbon nanomaterials between MXene layers or creating mesopores on MXene, the films were made more accessible to intercalation and

  11. Nanodiamonds act as Trojan horse for intracellular delivery of metal ions to trigger cytotoxicity.

    Science.gov (United States)

    Zhu, Ying; Zhang, Yu; Shi, Guosheng; Yang, Jinrong; Zhang, Jichao; Li, Wenxin; Li, Aiguo; Tai, Renzhong; Fang, Haiping; Fan, Chunhai; Huang, Qing

    2015-02-05

    Nanomaterials hold great promise for applications in the delivery of various molecules with poor cell penetration, yet its potential for delivery of metal ions is rarely considered. Particularly, there is limited insight about the cytotoxicity triggered by nanoparticle-ion interactions. Oxidative stress is one of the major toxicological mechanisms for nanomaterials, and we propose that it may also contribute to nanoparticle-ion complexes induced cytotoxicity. To explore the potential of nanodiamonds (NDs) as vehicles for metal ion delivery, we used a broad range of experimental techniques that aimed at getting a comprehensive assessment of cell responses after exposure of NDs, metal ions, or ND-ion mixture: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Trypan blue exclusion text, optical microscope observation, synchrotron-based scanning transmission X-ray microscopy (STXM) and micro X-ray fluorescence (μXRF) microscopy, inductively coupled plasma-mass spectrometry (ICP-MS), reactive oxygen species (ROS) assay and transmission electron microscopy (TEM) observation. In addition, theoretical calculation and molecular dynamics (MD) computation were used to illustrate the adsorption properties of different metal ion on NDs as well as release profile of ion from ND-ion complexes at different pH values. The adsorption capacity of NDs for different metal ions was different, and the adsorption for Cu2+ was the most strong among divalent metal ions. These different ND-ion complexes then had different cytotoxicity by influencing the subsequent cellular responses. Detailed investigation of ND-Cu2+ interaction showed that the amount of released Cu2+ from ND-Cu2+ complexes at acidic lysosomal conditions was much higher than that at neutral conditions, leading to the elevation of intracellular ROS level, which triggered cytotoxicity. By theoretical approaches, we demonstrated that the functional carbon surface and cluster structures of NDs made them

  12. Poultry litter-based activated carbon for removing heavy metal ions in water.

    Science.gov (United States)

    Guo, Mingxin; Qiu, Guannan; Song, Weiping

    2010-02-01

    Utilization of poultry litter as a precursor material to manufacture activated carbon for treating heavy metal-contaminated water is a value-added strategy for recycling the organic waste. Batch adsorption experiments were conducted to investigate kinetics, isotherms, and capacity of poultry litter-based activated carbon for removing heavy metal ions in water. It was revealed that poultry litter-based activated carbon possessed significantly higher adsorption affinity and capacity for heavy metals than commercial activated carbons derived from bituminous coal and coconut shell. Adsorption of metal ions onto poultry litter-based carbon was rapid and followed Sigmoidal Chapman patterns as a function of contact time. Adsorption isotherms could be described by different models such as Langmuir and Freundlich equations, depending on the metal species and the coexistence of other metal ions. Potentially 404 mmol of Cu2+, 945 mmol of Pb2+, 236 mmol of Zn2+, and 250-300 mmol of Cd2+ would be adsorbed per kg of poultry litter-derived activated carbon. Releases of nutrients and metal ions from litter-derived carbon did not pose secondary water contamination risks. The study suggests that poultry litter can be utilized as a precursor material for economically manufacturing granular activated carbon that is to be used in wastewater treatment for removing heavy metals.

  13. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya, E-mail: divya@chem.unipune.ac.in

    2015-05-15

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu{sup 2+}, Fe{sup 2+}, Ni{sup 2+} and Zn{sup 2+} in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu{sup 2+}, Fe{sup 2+} and Ni{sup 2+} caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe{sup 2+}, Cu{sup 2+}, Ni{sup 2+} and Zn{sup 2+}. • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions.

  14. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya

    2015-01-01

    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu 2+ , Fe 2+ , Ni 2+ and Zn 2+ in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu 2+ , Fe 2+ and Ni 2+ caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe 2+ , Cu 2+ , Ni 2+ and Zn 2+ . • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions

  15. Finite element modeling simulation-assisted design of integrated microfluidic chips for heavy metal ion stripping analysis

    International Nuclear Information System (INIS)

    Hong, Ying; Zou, Jianhua; Ge, Gang; Xiao, Wanyue; Shao, Jinjun; Dong, Xiaochen; Gao, Ling

    2017-01-01

    In this article, a transparent integrated microfluidic device composed of a 3D-printed thin-layer flow cell (3D-PTLFC) and an S-shaped screen-printed electrode (SPE) has been designed and fabricated for heavy metal ion stripping analysis. A finite element modeling (FEM) simulation is employed to optimize the shape of the electrode, the direction of the inlet pipeline, the thin-layer channel height and the sample flow rate to enhance the electron-enrichment efficiency for stripping analysis. The results demonstrate that the S-shaped SPE configuration matches the channel in 3D-PTLFC perfectly for the anodic stripping behavior of the heavy metal ions. Under optimized conditions, a wide linear range of 1–80 µ g l −1 is achieved for Pb 2+ detection with a limit of 0.3 µ g l −1 for the microfluidic device. Thus, the obtained integrated microfluidic device proves to be a promising approach for heavy metal ions stripping analysis with low cost and high performance. (paper)

  16. Effect of metal ions on the growth and metabolites production of ...

    African Journals Online (AJOL)

    Effect of metal ions on the growth and metabolites production of Ganoderma lucidum in submerged culture. YH Cui, KC Zhang. Abstract. The effects of several metal ions on the cell growth, production of polysaccharides by Ganoderma lucidum in submerged fermentation were studied. The results showed that 50 ppm Se2+ ...

  17. The Impact of Template Types on Polyeugenol to the Adsorption Selectivity of Ionic Imprinted Polymer (IIP) Fe Metal Ion

    Science.gov (United States)

    Djunaidi, M. C.; Haris, A.; Pardoyo; Rosdiana, K.

    2018-04-01

    The synthesis of IIP was carried out by variation of Fe(III) ion templates from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 compounds which then tested IIP selectivity to the Fe metal ions through adsorption process. Ionic Imprinted Polymer (IIP) is a method of printing metal ions bound in a polymer, subsequently released from the polymer matrix to produce a suitable imprint for the target ion. The purposes of this study were to produce IIP from Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates, to know the effect of templates on adsorption selectivity of IIP involving imprint cavity, and to know the impact of metal competitor on the selectivity adsorption of IIP to the Fe metals. The results obtained showed that IIP synthesized by variations of Fe(NO3)3, K3[Fe(CN)6] and NH4Fe(SO4)2 templates were successfully synthesized. The adsorption selectivity of Fe (III) metal ion in the Fe(NO3)3 template was greater than that of in the K3[Fe(CN)6] and NH4Fe(SO4)2 templates. The adsorption selectivity of Fe was greater on Fe-Cr compared to on Fe-Cd and Fe-Pb.

  18. Poisoning of liquid membrane carriers in extraction of metal ions

    International Nuclear Information System (INIS)

    Wang, Yuchun; Wang, Dexian

    1992-01-01

    As means of effective separation and preconcentration, emulsion liquid membranes (ELMs) have found application in many fields including biochemical separation, wastewater treatment, hydrometallurgy, and preconcentration in analytical chemistry. In the extraction of desired metal (scandium, mixed rare earths) ions using chelating extractants (TTA, HDEHP) as liquid membrane carriers, the carriers will become poisoned owing to the presence of even minute quantity of certain high ionic potential ions in the feed solution. The reason for the poisoning of carriers is that those ions have so much greater affinity than the desired ions for the membrane carrier that the ion-carrier coordination compound cannot be stripped at the interior interface of the membrane and gradually no more free carrier transports any metal ions across the membrane. The calculated results are in agreement with the experiments, and methods to avoid the poisoning are given in the paper

  19. Synthesis, Characterizations, and Applications of Metal-Ions Incorporated High Quality MCM-41 Catalysts

    International Nuclear Information System (INIS)

    Lim, Steven S.; Haller, Gary L.

    2013-01-01

    Various metal ions (transition and base metals) incorporated MCM-41 catalysts can be synthesized using colloidal and soluble silica with non-sodium involved process. Transition metal ion-typically V 5+ , Co 2+ , and Ni 2+ -incorporated MCM-41 catalysts were synthesized by isomorphous substitution of Si ions in the framework. Each incorporated metal ion created a single species in the silica framework, single-site solid catalyst, showing a substantial stability in reduction and catalytic activity. Radius of pore curvature effect was investigated with Co-MCM-41 by temperature programmed reduction (TPR). The size of metallic Co clusters, sub-nanometer, could be controlled by a proper reduction treatment of Co-MCM-41 having different pore size and the initial pH adjustment of the Co-MCM-41 synthesis solution. These small metallic clusters showed a high stability under a harsh reaction condition without serious migration, resulting from a direct anchoring of small metallic clusters to the partially or unreduced metal ions on the surface. After a complete reduction, partial occlusion of the metallic cluster surface by amorphous silica stabilized the particles against aggregations. As a probe reaction of particle size sensitivity, carbon single wall nanotubes (SWNT) were synthesized using Co-MCM-41. A metallic cluster stability test was performed by CO methanation using Co- and Ni-MCM-41. Methanol and methane partial oxidations were carried out with V-MCM-41, and the radius of pore curvature effect on the catalytic activity was investigated

  20. Spent lithium-ion battery recycling - Reductive ammonia leaching of metals from cathode scrap by sodium sulphite.

    Science.gov (United States)

    Zheng, Xiaohong; Gao, Wenfang; Zhang, Xihua; He, Mingming; Lin, Xiao; Cao, Hongbin; Zhang, Yi; Sun, Zhi

    2017-02-01

    Recycling of spent lithium-ion batteries has attracted wide attention because of their high content of valuable and hazardous metals. One of the difficulties for effective metal recovery is the separation of different metals from the solution after leaching. In this research, a full hydrometallurgical process is developed to selectively recover valuable metals (Ni, Co and Li) from cathode scrap of spent lithium ion batteries. By introducing ammonia-ammonium sulphate as the leaching solution and sodium sulphite as the reductant, the total selectivity of Ni, Co and Li in the first-step leaching solution is more than 98.6% while it for Mn is only 1.36%. In detail understanding of the selective leaching process is carried out by investigating the effects of parameters such as leaching reagent composition, leaching time (0-480min), agitation speed (200-700rpm), pulp density (10-50g/L) and temperature (323-353K). It was found that Mn is primarily reduced from Mn 4+ into Mn 2+ into the solution as [Formula: see text] while it subsequently precipitates out into the residue in the form of (NH 4 ) 2 Mn(SO 3 ) 2 ·H 2 O. Ni, Co and Li are leached and remain in the solution either as metallic ion or amine complexes. The optimised leaching conditions can be further obtained and the leaching kinetics is found to be chemical reaction control under current leaching conditions. As a result, this research is potentially beneficial for further optimisation of the spent lithium ion battery recycling process after incorporating with metal extraction from the leaching solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Multiheteromacrocycles that complex metal ions. Third progress report, 1 May 1976--30 April 1977

    International Nuclear Information System (INIS)

    Cram, D.J.

    1977-01-01

    The overall objective of this research is to design, synthesize and evaluate cyclic and polycyclic host organic compounds for their abilities to complex and lipophilize guest metal ions, their complexes and clusters. Host organic compounds consist of strategically placed solvating, coordinating and ion-pairing sites tied together by covalent bonds through hydrocarbon units around cavities shaped to be occupied by guest metal ions, or metal ions plus their ligands. Specificity in complexation is sought by matching the following properties of host and guest: cavity and metal ion sizes; geometric arrangements of binding sites; numbers of binding sites; characters of binding sites; and valences. The specific compounds synthesized and their complexing and lipophilizing properties are summarized

  2. Removal and recovery of metal ions from process and waste streams using polymer filtration

    International Nuclear Information System (INIS)

    Jarvinen, G.D.; Smith, B.F.; Robison, T.W.; Kraus, K.M.; Thompson, J.A.

    1999-01-01

    Polymer Filtration (PF) is an innovative, selective metal removal technology. Chelating, water-soluble polymers are used to selectively bind the desired metal ions and ultrafiltration is used to concentrate the polymer-metal complex producing a permeate with low levels of the targeted metal ion. When applied to the treatment of industrial metal-bearing aqueous process streams, the permeate water can often be reused within the process and the metal ions reclaimed. This technology is applicable to many types of industrial aqueous streams with widely varying chemistries. Application of PF to aqueous streams from nuclear materials processing and electroplating operations will be described

  3. Removal of Cu(II) metal ions from aqueous solution by amine functionalized magnetic nanoparticles

    Science.gov (United States)

    Kothavale, V. P.; Karade, V. C.; Waifalkar, P. P.; Sahoo, Subasa C.; Patil, P. S.; Patil, P. B.

    2018-04-01

    The adsorption behavior of Cu(II) metal cations was investigated on the amine functionalized magnetic nanoparticles (MNPs). TheMNPs were synthesized by thesolvothermal method and functionalized with (3-Aminopropyl)triethoxysilane (APTES). MNPs were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and vibrating sample magnetometer (VSM). The MNPs have pure magnetite phase with particle size around 10-12 nm. MNPs exhibits superparamagnetic behavior with asaturation magnetization of 68 emu/g. The maximum 38 % removal efficiency was obtained for Cu(II) metal ions from the aqueous solution.

  4. Effect of electron-excitation on radiation damage in ion-irradiated FCC metals

    International Nuclear Information System (INIS)

    Iwase, Akihiro

    1989-06-01

    FCC metals (Al, Cu, Ag, Ni) were irradiated with 0.5-1.8 MeV H, He, N and Ar ions, and 84-126 MeV C, F, Si, Cl, Br and I ions at liquid helium temperatures. After the irradiations, thermal annealing experiments were performed up to 300 K. Anomalous reduction of Stage-I recovery was observed in Al and Ni irradiated with high-energy (∼100 MeV) heavy ions. Radiation annealing by 100 MeV I ions was studied in predoped Ni and Cu. The experimental results were analyzed by using a new model which describes the production and radiation annealing of two or more types of defects. The extraordinarily large cross sections for subthreshold recombination of Stage-I defects were obtained in Ni. These results show that in Al and Ni, the energies transferred from the excited electrons to lattice through the electron-lattice interaction contribute to the annihilations of defects during irradiation. (author)

  5. C-H functionalization: thoroughly tuning ligands at a metal ion, a chemist can greatly enhance catalyst's activity and selectivity.

    Science.gov (United States)

    Shul'pin, Georgiy B

    2013-09-28

    This brief essay consists of a few "exciting stories" devoted to relations within a metal-complex catalyst between a metal ion and a coordinated ligand. When, as in the case of a human couple, the rapport of the partners is cordial and a love cements these relations, a chemist finds an ideal married couple, in other words he obtains a catalyst of choice which allows him to functionalize C-H bonds very efficiently and selectively. Examples of such lucky marriages in the catalytic world of ions and ligands are discussed here. Activity of the catalyst is characterized by turnover number (TON) or turnover frequency (TOF) as well as by yield of a target product. Introducing a chelating N,N- or N,O-ligand to the catalyst molecule (this can be an iron or manganese derivative) sharply enhances its activity. However, the activity of vanadium derivatives (with additionally added to the solution pyrazinecarboxylic acid, PCA) as well as of various osmium complexes does not dramatically depend on the nature of ligands surrounding metal ions. Complexes of these metals are very efficient catalysts in oxidations with H2O2. Osmium derivatives are record-holders exhibiting extremely high TONs whereas vanadium complexes are on the second position. Finally, elegant examples of alkane functionalization on the ions of non-transition metals (aluminium, gallium etc.) are described when one ligand within the metal complex (namely, hydroperoxyl ligand HOO(-)) helps other ligand of this complex (H2O2 molecule coordinated to the metal) to disintegrate into two species, generating very reactive hydroxyl radical. Hydrogen peroxide molecule, even ligated to the metal ion, is perfectly stable without the assistance of the neighboring HOO(-) ligand. This ligand can be easily oxidized donating an electron to its partner ligand (H2O2). In an analogous case, when the central ion in the catalyst is a transition metal, this ion changing its oxidation state can donate an electron to the coordinated H2O2

  6. Sorption of Molecular Oxygen by Metal-Ion Exchanger Nanocomposites

    Science.gov (United States)

    Krysanov, V. A.; Plotnikova, N. V.; Kravchenko, T. A.

    2018-03-01

    Kinetic features are studied of the chemisorption and reduction of molecular oxygen from water by metal-ion exchanger nanocomposites that differ in the nature of the dispersed metal and state of oxidation. In the Pd equilibrium sorption coefficient for oxygen dissolved in water ranges from 20 to 50, depending on the nature and oxidation state of the metal component.

  7. Adverse reaction to metal debris in a consecutive series of DUROM™ hip resurfacing: pseudotumour incidence and metal ion concentration.

    Science.gov (United States)

    Hartmann, Albrecht; Kieback, Jan-Dirk; Lützner, Jörg; Günther, Klaus-Peter; Goronzy, Jens

    2017-07-25

    The aim of this study was to evaluate the incidence of adverse reactions to metal debris (ARMD) in a consecutive series of DUROM™ Hip Resurfacing Arthroplasty (HRA) at mid-term follow-up. Between October 2003 and March 2007 a total of 134 consecutive DUROM™ HRA in 121 patients were performed at our institution. Follow-up could be obtained in 101 unrevised patients (83%) at a mean time of 8.51 ± 0.97 years postoperatively and included patient-related outcome measurement, plain radiographs, MARS-MRI as well as whole blood metal ion assessment. 17 (16.5%) out of 103 hips revealed pseudotumour occurrence in MRI investigation, 1 (10.6%) with a diameter of ≥2 cm. Higher incidence of pseudotumours was found patients with femoral component size 7 μg/l. In contrast to cobalt determination, only elevated chromium values showed a positive association with pseudotumour occurrence and size. A significant proportion of patients developed pseudotumours and metal ion elevation in a consecutive cohort of DUROM™ HRA after mid-term follow-up. The incidence, however, seems not to differ from results of other well performing resurfacing brands; clinical relevance of our findings is unclear. Regarding potential local as well as systemic effects of metal particle release, close follow-up of patients is essential, even with clinically well-performing implants.

  8. Removal of heavy-metal ions from dilute waste streams using membrane-based hybrid systems

    International Nuclear Information System (INIS)

    Friesen, D.T.; Edlund, D.J.

    1993-01-01

    At Bend research, the authors have developed hybrid systems that couple a process that removes solvent (water) and a process that removes solute (metal ions) such that toxic heavy-metal ions can be efficiently and selectively removed to very low levels while simultaneously concentrating the heavy-metal ions in relatively pure form. Although this technology is broadly applicable, the authors are focusing on the development of a system to treat groundwater that is contaminated with heavy-metal ions. The process utilizes coupled transport and reverse osmosis to reduce chromium and uranium concentration down to parts-per-billion levels

  9. No association between pseudotumors, high serum metal-ion levels and metal hypersensitivity in large-head metal-on-metal total hip arthroplasty at 5-7-year follow-up

    DEFF Research Database (Denmark)

    Hjorth, Mette Holm; Stilling, Maiken; Soballe, Kjeld

    2015-01-01

    -ion concentrations were measured, metal allergy and atopic dermatitis were evaluated, and the questionnaires of the Oxford Hip Score (OHS), Harris Hip Score (HHS) and the Short-Form Health Survey (SF-36) were completed. RESULTS: Pseudotumors were found in eight patients, but they were asymptomatic and their serum...... pseudotumor formation, serum metal-ion levels, metal patch test reactivity, and atopic dermatitis. However, clinicians should be aware of asymptomatic pseudotumors, and we advise further exploration into the mechanisms involved in the pathogenesis of pseudotumors.......OBJECTIVE: The relationship between metal wear debris, pseudotumor formation and metal hypersensitivity is complex and not completely understood. The purpose of this study was to assess the prevalence of pseudotumor formation in a consecutive series of metal-on-metal (MoM) total hip arthroplasty...

  10. Metal ion reactive thin films using spray electrostatic LbL assembly.

    Science.gov (United States)

    Krogman, Kevin C; Lyon, Katharine F; Hammond, Paula T

    2008-11-20

    By using the spray-layer-by-layer (Spray-LbL) technique, the number of metal counterions trapped within LbL coatings is significantly increased by kinetically freezing the film short of equilibrium, potentially limiting interchain penetration and forcing chains to remain extrinsically compensated to a much greater degree than observed in the traditional dipped LbL technique. The basis for the enhanced entrapment of metal ions such as Cu2+, Fe2+, and Ag+ is addressed, including the equilibrium driving force for extrinsic compensation by soft versus hard metal ions and the impact of Spray-LbL on the kinetics of polymer-ion complexation. These polymer-bound metal-ion coatings are also demonstrated to be effective treatments for air filtration, functionalizing existing filters with the ability to strongly bind toxic industrial compounds such as ammonia or cyanide gases, as well as chemical warfare agent simulants such as chloroethyl ethyl sulfide. On the basis of results reported here, future work could extend this method to include other toxic soft-base ligands such as carbon monoxide, benzene, or organophosphate nerve agents.

  11. Metal-ion catalyzed polymerization in the eutectic phase in water-ice

    DEFF Research Database (Denmark)

    Monnard, Pierre-Alain; Szostak, Jack W.

    2008-01-01

    The emergence of an RNA world requires among other processes the non-enzymatic, template-directed replication of genetic polymers such as RNA or related nucleic acids, possibly catalyzed by metal ions. The absence of uridilate derivative polymerization on adenine containing templates has been...... the main issue preventing an efficient template-directed RNA polymerization. We report here the investigation of template-directed RNA polymerization in the eutectic phase in water-ice. In particular, it was found that activated Uridilate monomers in the presence of metal-ion catalysts could efficiently......-pairing opportunities. These results suggest that a template-directed RNA polymerization catalyzed by metal-ions could be carried out under eutectic phase in water-ice conditions....

  12. The ion-electron correlation function in liquid metals

    International Nuclear Information System (INIS)

    Takeda, S.; Tamaki, S.; Waseda, Y.

    1985-01-01

    The structure factors of liquid Zn at 723 K, Sn at 523 K and Bi at 573 K have been determined by neutron diffraction with sufficient accuracy and compared with those of X-ray diffraction. A remarkable difference in the structural information between the two methods is clearly found around the first peak region as well as in the slightly varied peak positions, and it is apparently larger than the experimental errors. With these facts in mind, a new method evaluating the ion-electron correlation function in liquid metals has been proposed by using the measured structural data of X-rays and neutrons, with the help of theoretical values of the electron-electron correlation function by he Utsumi-Ichimaru scheme. This method has been applied to liquid Zn, Sn and Bi, and the radial distribution function of valence electrons around an ion has been estimated, from which the ionic radius and the schematic diagram of the electron distribution map are obtained. The ionic radii evaluated in this work have been found to agree well with those proposed by Pauling. (author)

  13. Thin-layer chromatography of 49 metal ions on stannic antimonate in aqueous and mixed solvent systems containing dimethylsulfoxide: quantitative separation of uranium from numerous metal ions

    International Nuclear Information System (INIS)

    Qureshi, M.; Varshney, K.G.; Rajput, R.P.S.

    1976-01-01

    Thin-layer chromatography of 40 metal ions in 31 aqueous and mixed solvent systems has been performed on stannic antimonate ion-exchange material. Dimethylsulfoxide has been utilized to resolve such binary mixtures as La 3+ and Ce 3+ from Pr 3+ , Nd 3+ , and Sm 3+ ; VO 2+ from Ti 4+ , Nb 5+ , and Ta 5+ ; Ga 3+ from In 3+ , Tl + , and Y 3+ ; Fe 3+ from VO 2+ ; and Mg 2+ from Al 3+ . Quantitative separation of 200 to 800 μg U from its binary mixtures and from the synthetic mixtures containing Mg 2+ , Bi 3+ , Fe 3+ , Th 4+ , Ce 4+ , Cr 3+ , Zr 4+ , Hf 4+ , Ti 4+ Mn 2+ , Cu 2+ , Ce 3+ , In 3+ , Y 3+ , Ca 2+ , Co 2+ , Tl + , Nb 5+ , and Ag + has been obtained

  14. Analysis of metallic pigments by ion microbeam

    International Nuclear Information System (INIS)

    Pelicon, P.; Klanjsek-Gunde, M.; Kunaver, M.; Simcic, J.; Budnar, M.

    2002-01-01

    Metallic paints consist of metallic flakes dispersed in a resinous binder, i.e. a light-element polymer matrix. The spatial distribution and orientation of metallic flakes inside the matrix determines the covering efficiency of the paint, glossiness, and its angular-dependent properties such as lightness flop or color flop (two-tone). Such coatings are extensively used for a functional (i.e. security) as well as decorative purpose. The ion microbeam analysis of two types of silver paint with imbedded metallic flakes has been performed to determine the spatial distribution of the aluminum flakes in paint layer. The average sizes of the aluminum flakes were 23 μm (size distribution 10-37) and 49 μm (size distribution 34-75), respectively. The proton beam with the size of 2x2 μm 2 at Ljubljana ion microprobe has been used to scan the surface of the pigments. PIXE mapping of Al Kα map shows lateral distribution of the aluminum flakes, whereas the RBS slicing method reveals tomograms of the flakes in uppermost 7 μm of the pigment layer. The series of point analysis aligned over the single flake reveal the flake angle in respect to the polymer matrix surface. The angular sensitivity is well below 1 angular degree

  15. NOTE: Ranges of ions in metals for use in particle treatment planning

    Science.gov (United States)

    Jäkel, Oliver

    2006-05-01

    In proton and ion radiotherapy, the range of particles is calculated from x-ray computed tomography (CT) numbers. Due to the strong absorption of x-rays in a metal and a cut-off for large Hounsfield units (HU) in the software of most CT-scanners, a range calculation in metals cannot be based on the measured HU. This is of special importance when metal implants such as gold fillings or hip prostheses are close to the treatment volume. In order to overcome this problem in treatment planning for heavy charged particles, the correct ranges of ions in the metal relative to water have to be assigned in the CT data. Measurements and calculations of carbon ion ranges in various metals are presented that can be used in treatment planning to allow for a more accurate range calculation of carbon ion beams in titanium, steel, tungsten and gold. The suggested values for the relative water-equivalent range and their uncertainties are 3.13 (±3%) for titanium, 5.59 (±3%) for stainless steel and 10.25 (±4%) for gold.

  16. A review on various electrochemical techniques for heavy metal ions detection with different sensing platforms.

    Science.gov (United States)

    Bansod, BabanKumar; Kumar, Tejinder; Thakur, Ritula; Rana, Shakshi; Singh, Inderbir

    2017-08-15

    Heavy metal ions are non-biodegradable and contaminate most of the natural resources occurring in the environment including water. Some of the heavy metals including Lead (Pb), Mercury (Hg), Arsenic (As), Chromium (Cr) and Cadmium (Cd) are considered to be highly toxic and hazardous to human health even at trace levels. This leads to the requirement of fast, accurate and reliable techniques for the detection of heavy metal ions. This review presents various electrochemical detection techniques for heavy metal ions those are user friendly, low cost, provides on-site and real time monitoring as compared to other spectroscopic and optical techniques. The categorization of different electrochemical techniques is done on the basis of different types of detection signals generated due to presence of heavy metal ions in the solution matrix like current, potential, conductivity, electrochemical impedance, and electrochemiluminescence. Also, the recent trends in electrochemical detection of heavy metal ions with various types of sensing platforms including metals, metal films, metal oxides, nanomaterials, carbon nano tubes, polymers, microspheres and biomaterials have been evoked. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Bioleaching of valuable metals from spent lithium-ion mobile phone batteries using Aspergillus niger

    Science.gov (United States)

    Horeh, N. Bahaloo; Mousavi, S. M.; Shojaosadati, S. A.

    2016-07-01

    In this paper, a bio-hydrometallurgical route based on fungal activity of Aspergillus niger was evaluated for the detoxification and recovery of Cu, Li, Mn, Al, Co and Ni metals from spent lithium-ion phone mobile batteries under various conditions (one-step, two-step and spent medium bioleaching). The maximum recovery efficiency of 100% for Cu, 95% for Li, 70% for Mn, 65% for Al, 45% for Co, and 38% for Ni was obtained at a pulp density of 1% in spent medium bioleaching. The HPLC results indicated that citric acid in comparison with other detected organic acids (gluconic, oxalic and malic acid) had an important role in the effectiveness of bioleaching using A. niger. The results of FTIR, XRD and FE-SEM analysis of battery powder before and after bioleaching process confirmed that the fungal activities were quite effective. In addition, bioleaching achieved higher removal efficiency for heavy metals than the chemical leaching. This research demonstrated the great potential of bio-hydrometallurgical route to recover heavy metals from spent lithium-ion mobile phone batteries.

  18. Pesticides Curbing Soil Fertility: Effect of Complexation of Free Metal Ions

    Science.gov (United States)

    Kaur, Sukhmanpreet; Kumar, Vijay; Chawla, Mohit; Cavallo, Luigi; Poater, Albert; Upadhyay, Niraj

    2017-07-01

    Researchers have suggested that the reason behind infertility is pernicious effect of broad spectrum pesticides on non target, beneficial microorganism of soil. Here, studying the chelating effect of selective organophosphate and carbamate pesticides with essential metal ions, at all possible combinations of three different pH (4±0.05, 7±0.05 and 9±0.05) and three different temperatures (15±0.5°C, 30±0.5°C and 45±0.5°C), shows very fast rate of reaction which further increases with increase of pH and temperature. Carbonyl oxygen of carbamate and phosphate oxygen of organophosphate were found to be common ligating sites among all the complexes. Formed metal complexes were found to be highly stable and water insoluble on interaction with essential metal ions in solvent medium as well as over silica. Density functional theory (DFT) calculations not only reinforced the experimental observations, but, after a wide computational conformational analysis, unraveled the nature of the high stable undesired species that consist of pesticides complexed by metal ions from the soil. All in all, apart from the direct toxicity of pesticides, the indirect effect by means of complexation of free metal ions impoverishes the soil.

  19. Pesticides Curbing Soil Fertility: Effect of Complexation of Free Metal Ions

    KAUST Repository

    Kaur, Sukhmanpreet

    2017-07-04

    Researchers have suggested that the reason behind infertility is pernicious effect of broad spectrum pesticides on non target, beneficial microorganism of soil. Here, studying the chelating effect of selective organophosphate and carbamate pesticides with essential metal ions, at all possible combinations of three different pH (4 ± 0.05, 7 ± 0.05 and 9 ± 0.05) and three different temperatures (15 ± 0.5°C, 30 ± 0.5°C and 45 ± 0.5°C), shows very fast rate of reaction which further increases with increase of pH and temperature. Carbonyl oxygen of carbamate and phosphate oxygen of organophosphate were found to be common ligating sites among all the complexes. Formed metal complexes were found to be highly stable and water insoluble on interaction with essential metal ions in solvent medium as well as over silica. Density functional theory (DFT) calculations not only reinforced the experimental observations, but, after a wide computational conformational analysis, unraveled the nature of the high stable undesired species that consist of pesticides complexed by metal ions from the soil. All in all, apart from the direct toxicity of pesticides, the indirect effect by means of complexation of free metal ions impoverishes the soil.

  20. Pesticides Curbing Soil Fertility: Effect of Complexation of Free Metal Ions

    KAUST Repository

    Kaur, Sukhmanpreet; Kumar, Vijay; Chawla, Mohit; Cavallo, Luigi; Poater, Albert; Upadhyay, Niraj

    2017-01-01

    Researchers have suggested that the reason behind infertility is pernicious effect of broad spectrum pesticides on non target, beneficial microorganism of soil. Here, studying the chelating effect of selective organophosphate and carbamate pesticides with essential metal ions, at all possible combinations of three different pH (4 ± 0.05, 7 ± 0.05 and 9 ± 0.05) and three different temperatures (15 ± 0.5°C, 30 ± 0.5°C and 45 ± 0.5°C), shows very fast rate of reaction which further increases with increase of pH and temperature. Carbonyl oxygen of carbamate and phosphate oxygen of organophosphate were found to be common ligating sites among all the complexes. Formed metal complexes were found to be highly stable and water insoluble on interaction with essential metal ions in solvent medium as well as over silica. Density functional theory (DFT) calculations not only reinforced the experimental observations, but, after a wide computational conformational analysis, unraveled the nature of the high stable undesired species that consist of pesticides complexed by metal ions from the soil. All in all, apart from the direct toxicity of pesticides, the indirect effect by means of complexation of free metal ions impoverishes the soil.

  1. Multiheteromacrocycles that Complex Metal Ions. Sixth Progress Report, 1 May 1979-30 April 1980

    Science.gov (United States)

    Cram, D. J.

    1980-01-15

    Objective is to design synthesize, and evaluate cyclic and polycyclic host organic compounds for their abilities to complex and lipophilize guest metal ions, their complexes, and their clusters. Host organic compounds consist of strategically placed solvating, coordinating, and ion-pairing sites tied together by covalent bonds through hydrocarbon units around cavities shaped to be occupied by guest metal ions or by metal ions plus their ligands. Specificity in complexation is sought by matching the following properties of host and guest: cavity and metal ion sizes; geometric arrangements of binding sites; number of binding sites; character of binding sites; and valences. During this period, hemispherands based on an aryloxy or cyclic urea unit, spherands based on aryloxyl units only, and their complexes with alkali metals and alkaline earths were investigated. An attempt to separate {sup 6}Li and {sup 7}Li by gel permeation chromatography of lithiospherium chloride failed. (DLC)

  2. A flexible ligand-based wavy layered metal-organic framework for lithium-ion storage.

    Science.gov (United States)

    An, Tiance; Wang, Yuhang; Tang, Jing; Wang, Yang; Zhang, Lijuan; Zheng, Gengfeng

    2015-05-01

    A substantial challenge for direct utilization of metal-organic frameworks (MOFs) as lithium-ion battery anodes is to maintain the rigid MOF structure during lithiation/delithiation cycles. In this work, we developed a flexible, wavy layered nickel-based MOF (C20H24Cl2N8Ni, designated as Ni-Me4bpz) by a solvothermal approach of 3,3',5,5'-tetramethyl-4,4'-bipyrazole (H2Me4bpz) with nickel(II) chloride hexahydrate. The obtained MOF materials (Ni-Me4bpz) with metal azolate coordination mode provide 2-dimensional layered structure for Li(+) intercalation/extraction, and the H2Me4bpz ligands allow for flexible rotation feature and structural stability. Lithium-ion battery anodes made of the Ni-Me4bpz material demonstrate excellent specific capacity and cycling performance, and the crystal structure is well preserved after the electrochemical tests, suggesting the potential of developing flexible layered MOFs for efficient and stable electrochemical storage. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Metal ion release from metallothioneins: proteolysis as an alternative to oxidation.

    Science.gov (United States)

    Peroza, Estevão A; dos Santos Cabral, Augusto; Wan, Xiaoqiong; Freisinger, Eva

    2013-09-01

    Metallothioneins (MTs) are among others involved in the cellular regulation of essential Zn(II) and Cu(I) ions. However, the high binding affinity of these proteins requires additional factors to promote metal ion release under physiological conditions. The mechanisms and efficiencies of these processes leave many open questions. We report here a comprehensive analysis of the Zn(II)-release properties of various MTs with special focus on members of the four main subfamilies of plant MTs. Zn(II) competition experiments with the metal ion chelator 4-(2-pyridylazo)resorcinol (PAR) in the presence of the cellular redox pair glutathione (GSH)/glutathione disulfide (GSSG) show that plant MTs from the subfamilies MT1, MT2, and MT3 are remarkably more affected by oxidative stress than those from the Ec subfamily and the well-characterized human MT2 form. In addition, we evaluated proteolytic digestion with trypsin and proteinase K as an alternative mechanism for selective promotion of metal ion release from MTs. Also here the observed percentage of liberated metal ions depends strongly on the MT form evaluated. Closer evaluation of the data additionally allowed deducing the thermodynamic and kinetic properties of the Zn(II) release processes. The Cu(I)-form of chickpea MT2 was used to exemplify that both oxidation and proteolysis are also effective ways to increase the transfer of copper ions to other molecules. Zn(II) release experiments with the individual metal-binding domains of Ec-1 from wheat grain reveal distinct differences from the full-length protein. This triggers the question about the roles of the long cysteine-free peptide stretches typical for plant MTs.

  4. Electrochemical membrane reactor: In situ separation and recovery of chromic acid and metal ions

    International Nuclear Information System (INIS)

    Khan, Jeeshan; Tripathi, Bijay P.; Saxena, Arunima; Shahi, Vinod K.

    2007-01-01

    An electrochemical membrane reactor with three compartments (anolyte, catholyte and central compartment) based on in-house-prepared cation- and anion-exchange membrane was developed to achieve in situ separation and recovery of chromic acid and metal ions. The physicochemical and electrochemical properties of the ion-exchange membrane under standard operating conditions reveal its suitability for the proposed reactor. Experiments using synthetic solutions of chromate and dichromate of different concentrations were carried out to study the feasibility of the process. Electrochemical reactions occurring at the cathode and anode under operating conditions are proposed. It was observed that metal ion migrated through the cation-exchange membrane from central compartment to catholyte and OH - formation at the cathode leads to the formation of metal hydroxide. Simultaneously, chromate ion migrated through the anion-exchange membrane from central compartment to the anolyte and formed chromic acid by combining H + produced their by oxidative water splitting. Thus a continuous decay in the concentration of chromate and metal ion was observed in the central compartment, which was recovered separately in the anolyte and catholyte, respectively, from their mixed solution. This process was completely optimized in terms of operating conditions such as initial concentration of chromate and metal ions in the central compartment, the applied cell voltage, chromate and metal ion flux, recovery percentage, energy consumption, and current efficiency. It was concluded that chromic acid and metal ions can be recovered efficiently from their mixed solution leaving behind the uncharged organics and can be reused as their corresponding acid and base apart from the purifying water for further applications

  5. Evaluation of an expence of materials during ion implantation

    International Nuclear Information System (INIS)

    Bannikov, M.G.; Zlobin, N.; Zotov, A.V.; Vasilev, V.I.; Vasilev, I.P.

    2003-01-01

    Ion implantation is used for a surface modification. The implantation dose must be sufficient to obtain the required properties of a processed surface, but should not be exceeded to prevent over-expenditure of implanted materials. The latter is especially important when noble metals are used as an implanted material. The ion implanter includes a vacuum chamber, source of metal ions (target) and a vacuum pumping-out system. Ions of a plasma-forming gas sputter the target and ions of metal are then accelerated and implanted into surface treated. Ion implantation dose can be calculated from operation parameters such as ion beam current density and duration of implanting. The presence of the plasma-forming gas in the ion flow makes it difficult to determine the expenditure of an implanted metal itself. The objective of this paper is the more accurate definition of an expense of an implanted metal. Mass- spectrometric analysis of an ion beam together with the weighing of the target was used to determine the expense of an implanted metal. It was found that, depending on the implantation parameters, on average around 50% of a total ion flow are metal ions. Results obtained allow more precise definition of an implantation dose. Thus, over- expenditure of implanted metals can be eliminated. (author)

  6. Transition metal ions mediated tyrosine based short peptide amphiphile nanostructures inhibit bacterial growth.

    Science.gov (United States)

    Joshi, Khashti Ballabh; Singh, Ramesh; Mishra, Narendra Kumar; Kumar, Vikas; Vinayak, Vandana

    2018-05-17

    We report the design and synthesis of biocompatible small peptide based molecule for the controlled and targeted delivery of the encapsulated bioactive metal ions via transforming their internal nanostructures. Tyrosine based short peptide amphiphile (sPA) was synthesized which self-assembled into β-sheet like secondary structures. The self assembly of the designed sPA was modulated by using different bioactive transition metal ions which is confirmed by spectroscopic and microscopic techniques. These bioactive metal ions conjugated sPA hybrid structures are further used to develop antibacterial materials. It is due to the excellent antibacterial activity of zinc ions that the growth of clinically relevant bacteria such as E. Coli was inhibited in the presence of zinc-sPA conjugate. The bacterial test demonstrated that owing to high biocompatibility with bacterial cell, the designed sPA worked as metal ions delivery agent and therefore it can show great potential in locally addressing bacterial infections. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Effect of transition metal ions on the conductivity and stability of stabilized zirconia

    DEFF Research Database (Denmark)

    Lybye, D.; Mogensen, Mogens Bjerg

    2007-01-01

    the effect of co-doping with smaller transition metal ions such as Ti-, Fe- and Mn-ions. Many of the ionic radii of the transition metal ions are too small compared to the host lattice ionic radius of zirconium. Here we explore the effect of a) the small ionic radii compared to the large ionic radii...

  8. Spectrophotometric determination of some metal ions using hydrazones

    International Nuclear Information System (INIS)

    Mohammed, M. S.

    2000-05-01

    In this research many starting materials were prepared, like methyl salicylate and salicylic acid hydrazide from which different derivatives of hydrazones were synthesized by coupling with carbonyl compounds like benzil monoxime and benzil mono hydrazone which are prepared and others like salicylaldehyde and benzoin. The hydrazones that were synthesized are salicylaldehyde salicylic acid hydrazone, benzoin salicylic acid hydrazone, benzil mono hydrazone salicylic acid hydrazone and benzil monoxime salicylic acid hydrazone. These reagents were determined by different methods, IR spectrophotometric determination, the nitrogen content method and melting point determination. These hydrazones act as ligands for determination of some metal ions by making different coloured complexes that were prepared for eight hydrazones with eight metal ions U (VI), Fe (II), Fe (III), Co (II), V (II), Mo (VI), Ni (II) and Cu (II). These complexes were determined by ultraviolet and visible spectrophotometer (UV/VIS) to detect their absorbance and wavelengths (λ max). The two hydrazones salicylaldehyde salicylic acid-hydrazone and benzoin salicylic acid hydrazone, were selected for determination of five metal ions (Fe (II), Fe (III), U (VI), Ni (II) and Cu (II)), using two micelles sodium n-dodecyl sulphate and pyridinium hexa decyl bromide mono hydrate. Their absorbance and wavelengths were detected using UV/VIS spectrophotometer. (Author)

  9. BIOSORBENTS – PROSPECTIVE MATERIALS FOR HEAVY METAL IONS EXTRACTION FROM WASTEWATER

    Directory of Open Access Journals (Sweden)

    О. Kovalenko

    2018-04-01

    Full Text Available The article deals with ecological safety, resource saving, economic efficienty in the technologies of wastewater purification from heavy metals ions. It is shown that modern technologies of wastewater purification from such substances need to be improved. А promising way to solve this problem is the production and wide use of carbon sorbents obtained from the waste of processing agricultural raw materials and waste generated at food enterprises. Scientific research is actively carried out in this area. This is due to the possibility of organizing the process of wastewater purification from heavy metal ions in a cheap and effective way. The development of biosorbent production is relevant for Ukraine, as the development of agriculture and food industry is of primary importance. The article presents the results of an analytical review of literary sources on various aspects of the scientific problem. In particular, possible sources of raw materials for the production of biosorbents, classical and modified technologies for their production, mechanisms of biosorption using raw materials with different chemical composition, sorption characteristics of biosorbents, and indicators of the economic efficiency of their production are considered.

  10. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    International Nuclear Information System (INIS)

    Zhang, Yuxiao; Zhang, Jianming; Liu, Yang; Huang, Hui; Kang, Zhenhui

    2012-01-01

    Highlights: ► Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. ► MPCS was covalently modified by cysteine (MPCS–CO–Cys). ► MPCS–CO–Cys was first time used in electrochemical detection of heavy metal ions. ► Heavy metal ions such as Pb 2+ and Cd 2+ can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  11. Metallic Sn-Based Anode Materials: Application in High-Performance Lithium-Ion and Sodium-Ion Batteries.

    Science.gov (United States)

    Ying, Hangjun; Han, Wei-Qiang

    2017-11-01

    With the fast-growing demand for green and safe energy sources, rechargeable ion batteries have gradually occupied the major current market of energy storage devices due to their advantages of high capacities, long cycling life, superior rate ability, and so on. Metallic Sn-based anodes are perceived as one of the most promising alternatives to the conventional graphite anode and have attracted great attention due to the high theoretical capacities of Sn in both lithium-ion batteries (LIBs) (994 mA h g -1 ) and sodium-ion batteries (847 mA h g -1 ). Though Sony has used Sn-Co-C nanocomposites as its commercial LIB anodes, to develop even better batteries using metallic Sn-based anodes there are still two main obstacles that must be overcome: poor cycling stability and low coulombic efficiency. In this review, the latest and most outstanding developments in metallic Sn-based anodes for LIBs and SIBs are summarized. And it covers the modification strategies including size control, alloying, and structure design to effectually improve the electrochemical properties. The superiorities and limitations are analyzed and discussed, aiming to provide an in-depth understanding of the theoretical works and practical developments of metallic Sn-based anode materials.

  12. Ion implantation enhanced metal-Si-metal photodetectors

    Science.gov (United States)

    Sharma, A. K.; Scott, K. A. M.; Brueck, S. R. J.; Zolper, J. C.; Myers, D. R.

    1994-05-01

    The quantum efficiency and frequency response of simple Ni-Si-Ni metal-semiconductor-metal (MSM) photodetectors at long wavelengths are significantly enhanced with a simple, ion-implantation step to create a highly absorbing region approx. 1 micron below the Si surface. The internal quantum efficiency is improved by a factor of approx. 3 at 860 nm (to 64%) and a full factor of ten at 1.06 microns (to 23%) as compared with otherwise identical unimplanted devices. Dark currents are only slightly affected by the implantation process and are as low as 630 pA for a 4.5-micron gap device at 10-V bias. Dramatic improvement in the impulse response is observed, 100 ps vs. 600 ps, also at 10-V bias and 4.5-micron gap, due to the elimination of carrier diffusion tails in the implanted devices. Due to its planar structure, this device is fully VLSI compatible. Potential applications include optical interconnections for local area networks and multi-chip modules.

  13. Lithium ion adsorptive properties of spinel-type manganese oxide obtained from MnOOH and Li2CO3

    International Nuclear Information System (INIS)

    Ooi, Kenta; Miyai, Yoshitaka; Katoh, Shunsaku; Abe, Mitsuo.

    1991-01-01

    Spinel-type manganese oxides were prepared by heating a mixture of MnOOH and Li 2 CO 3 (Li/Mn = 0.5) at different temperatures followed by an acid treatment with a HCl solution. Their adsorptive properties for alkali metal ions were investigated by measurement of distribution coefficient (Kd) and by pH titration. The adsorptive properties varied depending on the heating temperature. The sample obtained at 400degC showed the highest Li + adsorptivity from seawater. (author)

  14. Removal of metal ions from water using nanohydrogel tragacanth gum-g-polyamidoxime: isotherm and kinetic study.

    Science.gov (United States)

    Masoumi, Arameh; Ghaemy, Mousa

    2014-08-08

    A new biosorbent was prepared by grafting polyacrylonitrile onto iranian tragacanth gum (ITG), a naturally and abundantly available polysaccharide, and subsequent amidoximation in the presence of hydroxylamine hydrochloride. This nanohydrogel with amidoxime functional groups [C(NH2)NOH], named polyamidoxime-g-tragacanth (ITG-g-PAO), was characterized and used for the removal of metal ions from aqueous solution. The effect of pH, agitation time, concentration of adsorbate and amount of adsorbent on the extent of adsorption was investigated. The experimental data were analyzed by four isotherms and kinetics equations, and the results were fitted well with the Temkin isotherm and pseudo-second-order model. The maximum adsorption capacities (Qm) of ITG-g-PAO as obtained from Langmuir adsorption isotherm were found to be 100.0, 76.92, 71.42 and 66.67 (mgg(-1)) for the adsorption of metal ions in order of Co(II)>Zn(II)>Cr(III)>Cd(II). The experimental results demonstrate that the above selective order of adsorption capacity is due to formation of stable chelating ring between the bidentate amidoxime ligand and metal ion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Multicharged ion-induced emission from metal- and insulator surfaces related to magnetic fusion research

    Energy Technology Data Exchange (ETDEWEB)

    Winter, H.P. [Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Physik

    1997-01-01

    The edge region of magnetically confined plasmas in thermonuclear fusion experiments couples the hot plasma core with the cold first wall. We consider the dependence of plasma-wall interaction processes on edge plasma properties, with particular emphasis on the role of slow multicharged ions (MCI). After a short survey on the physics of slow MCI-surface interaction we discuss recent extensive studies on MCI-induced electron emission from clean metal surfaces conducted at impact velocities << 1 a.u., from which generally reliable total electron yields can be obtained. We then demonstrate the essentially different role of the MCI charge for electron emission from metallic and insulator surfaces, respectively. Furthermore, we present recent results on slow MCI-induced `potential sputtering` of insulators which, in contrast to the well established kinetic sputtering, already occurs at very low ion impact energy and strongly increases with the MCI charge state. (J.P.N.). 55 refs.

  16. Hydrometallurgical recovery of metal values by the use of ion exchange

    International Nuclear Information System (INIS)

    Higgins, I.R.

    1982-01-01

    This paper presented what had been accomplished to date using Packed Bed Continuous Countercurrent Ion Exchange (CCIX) and proposed plans for more comprehensive systems that include many soluble metals of value. Frontiers of hydrometallurgy cannot be breached until advantage is taken of a multitude of metal ions in solution. The future utilization of hydrometallurgical methodology depends on the success of extraction and separation unit operations and being accepted by mining companies. Examples are presented of CCIX projects in operation and pilot plants tested as proof of the special attractive features of the Chem-Seps CCIX system. An overall plan was presented for processing of sulfide type mineralization, with emphasis on making an effort to get ''complete'' dissolution of all metals of value. Continuous Countercurrent Ion Exchange plays a vital role in hydrometallurical processing because of the need to handle prodigious volumes of solution, tremendous tonnages of salts, and to compensate for poor ion exchange equilibrium. 11 figures. (DP)

  17. 1/f Fluctuations in ion implanted metal semiconductor contacts

    International Nuclear Information System (INIS)

    Stojanovic, M.; Marjanovic, N.; Radojevic, B.

    1998-01-01

    Ion implanted Metal-Semiconductor contacts is the most widely used structures in electrical devices. Weather complete devices or some parts are of interest, properties of metal-semiconductor junction strongly influence the quality and external characteristic of electronic devices. That is the reason why special attention is paid to the investigation of factor (noise for example) that could influence given junction. Low frequency 1/f fluctuations (noise) are constantly present in metal-semiconductor junction, so measurement of their level as well as the dependence on factors such as temperature must be taken into account in detailed analysis of electrical characteristics of devices such as contact, nuclear detector with surface barrier etc. In this paper we present the results of low frequency noise level measurements on TiN-Ti-Si structures produced by As + ion implantation. (author)

  18. Migration of metallic ions from screwposts into dentin and surrounding tissues

    International Nuclear Information System (INIS)

    Arvidson, K.; Wroblewski, R.

    1978-01-01

    Previous investigations have shown that corrosion and other electrochemical processes occur when different alloys or metals are found together in the same mouth. In the present report, when teeth were restored using non-noble metallic posts, the metals diffused out to surrounding hard and soft connective tissues. The material consisted of extracted teeth with screwposts and surrounding discolored connective tissues. The screwposts had been cemented to the teeth 3-10 years earlier. The distribution of metal ion was determined by means of energy-dispersive X-ray microanalysis. Copper and zinc were found in both hard and soft tissues. Relatively high concentrations of copper ions were identified in areas of the teeth with blue-green discolorations. Zinc ions were detected in the dentin; they most probably originated from the screwposts and the cement, but zinc is also found in normal human dentin. Copper, zinc, silver and iron were found in the dark discolorations of the gingiva adjacent to the extracted teeth. (author)

  19. Removal of some metal ions by activated carbon prepared from Phaseolus aureus hulls.

    Science.gov (United States)

    Rao, M Madhava; Ramana, D K; Seshaiah, K; Wang, M C; Chien, S W Chang

    2009-07-30

    Removal of lead [Pb(II)], zinc [Zn(II)], copper [Cu(II)], and cadmium [Cd(II)] from aqueous solutions using activated carbon prepared from Phaseolus aureus hulls (ACPAH), an agricultural waste was studied. The influence of various parameters such as effect of pH, contact time, adsorbent dose, and initial concentration of metal ions on the removal was evaluated by batch method. The removal of metal ions by ACPAH was pH dependent and the optimum pH values were 7.0, 8.0, 7.0 and 6.0 for Cu(II), Cd(II), Zn(II), and Pb(II), respectively. The sorption isotherms were studied using Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin isotherm models. The maximum adsorption capacity values of ACPAH for metal ions were 21.8 mg g(-1) for Pb(II), 21.2 mg g(-1) for Zn(II), 19.5 mg g(-1) for Cu(II), and 15.7 mg g(-1) for Cd(II). The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. Desorption experiments were carried out using HCl solution with a view to regenerate the spent adsorbent and to recover the adsorbed metal ions.

  20. Removal of some metal ions by activated carbon prepared from Phaseolus aureus hulls

    International Nuclear Information System (INIS)

    Rao, M. Madhava; Ramana, D.K.; Seshaiah, K.; Wang, M.C.; Chien, S.W. Chang

    2009-01-01

    Removal of lead [Pb(II)], zinc [Zn(II)], copper [Cu(II)], and cadmium [Cd(II)] from aqueous solutions using activated carbon prepared from Phaseolus aureus hulls (ACPAH), an agricultural waste was studied. The influence of various parameters such as effect of pH, contact time, adsorbent dose, and initial concentration of metal ions on the removal was evaluated by batch method. The removal of metal ions by ACPAH was pH dependent and the optimum pH values were 7.0, 8.0, 7.0 and 6.0 for Cu(II), Cd(II), Zn(II), and Pb(II), respectively. The sorption isotherms were studied using Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin isotherm models. The maximum adsorption capacity values of ACPAH for metal ions were 21.8 mg g -1 for Pb(II), 21.2 mg g -1 for Zn(II), 19.5 mg g -1 for Cu(II), and 15.7 mg g -1 for Cd(II). The experiments demonstrated that the removal of metal ions followed the pseudo-second-order kinetic model. Desorption experiments were carried out using HCl solution with a view to regenerate the spent adsorbent and to recover the adsorbed metal ions.

  1. Ion mobility studies of carbohydrates as group I adducts: isomer specific collisional cross section dependence on metal ion radius.

    Science.gov (United States)

    Huang, Yuting; Dodds, Eric D

    2013-10-15

    Carbohydrates play numerous critical roles in biological systems. Characterization of oligosaccharide structures is essential to a complete understanding of their functions in biological processes; nevertheless, their structural determination remains challenging in part due to isomerism. Ion mobility spectrometry provides the means to resolve gas phase ions on the basis of their shape-to-charge ratios, thus providing significant potential for separation and differentiation of carbohydrate isomers. Here, we report on the determination of collisional cross sections for four groups of isomeric carbohydrates (including five isomeric disaccharides, four isomeric trisaccharides, two isomeric pentasaccharides, and two isomeric hexasaccharides) as their group I metal ion adducts (i.e., [M + Li](+), [M + Na](+), [M + K](+), [M + Rb](+), and [M + Cs](+)). In all, 65 collisional cross sections were measured, the great majority of which have not been previously reported. As anticipated, the collisional cross sections of the carbohydrate metal ion adducts generally increase with increasing metal ion radius; however, the collisional cross sections were found to scale with the group I cation size in isomer specific manners. Such measurements are of substantial analytical value, as they illustrate how the selection of charge carrier influences carbohydrate ion mobility determinations. For example, certain pairs of isomeric carbohydrates assume unique collisional cross sections upon binding one metal ion, but not another. On the whole, these data suggest a role for the charge carrier as a probe of carbohydrate structure and thus have significant implications for the continued development and application of ion mobility spectrometry for the distinction and resolution of isomeric carbohydrates.

  2. Metal ion levels and lymphocyte counts

    DEFF Research Database (Denmark)

    Penny, Jeannette Ø; Varmarken, Jens-Erik; Ovesen, Ole

    2013-01-01

    BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA) an....../ppb. INTERPRETATION: Circulating T-lymphocyte levels may decline after surgery, regardless of implant type. Metal ions-particularly cobalt-may have a general depressive effect on T- and B-lymphocyte levels. Registered with ClinicalTrials.gov under # NCT01113762.......BACKGROUND AND PURPOSE: Wear particles from metal-on-metal arthroplasties are under suspicion for adverse effects both locally and systemically, and the DePuy ASR Hip Resurfacing System (RHA) has above-average failure rates. We compared lymphocyte counts in RHA and total hip arthroplasty (THA....... RESULTS: The T-lymphocyte counts for both implant types declined over the 2-year period. This decline was statistically significant for CD3(+)CD8(+) in the THA group, with a regression coefficient of -0.04 × 10(9)cells/year (95% CI: -0.08 to -0.01). Regression analysis indicated a depressive effect...

  3. Lifetime obtained by ion beam assisted deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chakaroun, M. [XLIM-MINACOM-UMR 6172, Faculte des Sciences et Techniques, 123 av. Albert Thomas, 87060 Limoges cedex (France); Antony, R. [XLIM-MINACOM-UMR 6172, Faculte des Sciences et Techniques, 123 av. Albert Thomas, 87060 Limoges cedex (France)], E-mail: remi.antony@unilim.fr; Taillepierre, P.; Moliton, A. [XLIM-MINACOM-UMR 6172, Faculte des Sciences et Techniques, 123 av. Albert Thomas, 87060 Limoges cedex (France)

    2007-09-15

    We have fabricated green organic light-emitting diodes based on tris-(8-hydroxyquinoline)aluminium (Alq3) thin films. In order to favor the charge carriers transport from the anode, we have deposited a N,N'-diphenyl-N,N'-bis (3-methylphenyl)-1,1'-diphenyl-4,4'-diamine (TPD) layer (hole transport layer) on a ITO anode. Cathode is obtained with a calcium layer covered with a silver layer. This silver layer is used to protect the other layers against oxygen during the OLED use. All the depositions are performed under vacuum and the devices are not exposed to air during their realisation. In order to improve the silver layer characteristics, we have realized this layer with the ion beam assisted deposition process. The aim of this process is to densify the layer and then reduce the permeation of H{sub 2}O and O{sub 2}. We have used argon ions to assist the silver deposition. All the OLEDs optoelectronic characterizations (I = f(V), L = f(V)) are performed in the ambient air. We compare the results obtained with the assisted layer with those obtained with a classical cathode realized by thermal unassisted evaporation. We have realized lifetime measurements in the ambient air and we discuss about the assisted layer influence on the OLEDs performances.

  4. Piezoelectric sensor for sensitive determination of metal ions based on the phosphate-modified dendrimer

    Science.gov (United States)

    Wang, S. H.; Shen, C. Y.; Lin, Y. M.; Du, J. C.

    2016-08-01

    Heavy metal ions arising from human activities are retained strongly in water; therefore public water supplies must be monitored regularly to ensure the timely detection of potential problems. A phosphate-modified dendrimer film was investigated on a quartz crystal microbalance (QCM) for sensing metal ions in water at room temperature in this study. The chemical structures and sensing properties were characterized by Fourier transform infrared spectroscopy and QCM measurement, respectively. This phosphate-modified dendrimer sensor can directly detect metal ions in aqueous solutions. This novel sensor was evaluated for its capacity to sense various metal ions. The sensor exhibited a higher sensitivity level and shorter response time to copper(II) ions than other sensors. The linear detection range of the prepared QCM based on the phosphate-modified dendrimer was 0.0001 ∼ 1 μM Cu(II) ions (R2 = 0.98). The detection properties, including sensitivity, response time, selectivity, reusability, maximum adsorption capacity, and adsorption equilibrium constants, were also investigated.

  5. Nanostructured Block Polymer Membranes as High Capacity Adsorbers for the Capture of Metal Ions from Water

    Science.gov (United States)

    Boudouris, Bryan; Weidman, Jacob; Mulvenna, Ryan; Phillip, William

    The efficient removal of metal ions from aqueous streams is of significant import in applications ranging from industrial waste treatment to the purification of drinking water. An emerging paradigm associated with this separation is one that utilizes membrane adsorbers as a means by which to bind metal salt contaminants. Here, we demonstrate that the casting of an A-B-C triblock polymer using the self-assembly and non-solvent induced phase separation (SNIPS) methodology results in a nanoporous membrane geometry. The nature of the triblock polymer affords an extremely high density of binding sites within the membrane. As such, we demonstrate that the membranes with binding capacities equal to that of state-of-the-art packed bed columns. Moreover, because the affinity of the C moiety can be tuned, highly selective binding events can occur based solely on the chemistry of the block polymer and the metal ions in solution (i.e., in a manner that is independent of the size of the metal ions). Due to these combined facts, these membranes efficiently remove heavy metal (e.g., lead- and cadmium-based) salts from contaminated water streams with greater than 95% efficiency. Finally, we show that the membranes can be regenerated through a simple treatment in order to provide long-lasting adsorber systems as well. Thus, it is anticipated that these nanostructured triblock polymer membranes are a platform by which to obtain next-generation water purification processes.

  6. Fabrication of γ-Fe2O3 Nanoparticles by Solid-State Thermolysis of a Metal-Organic Framework, MIL-100(Fe, for Heavy Metal Ions Removal

    Directory of Open Access Journals (Sweden)

    Shengtao Hei

    2014-01-01

    Full Text Available Porous γ-Fe2O3 nanoparticles were prepared via a solid-state conversion process of a mesoporous iron(III carboxylate crystal, MIL-100(Fe. First, the MIL-100(Fe crystal that served as the template of the metal oxide was synthesized by a low-temperature (<100°C synthesis route. Subsequently, the porous γ-Fe2O3 nanoparticles were fabricated by facile thermolysis of the MIL-100(Fe powders via a two-step calcination treatment. The obtained γ-Fe2O3 was characterized by X-ray diffraction (XRD, N2 adsorption, X-ray photoelectron spectroscopy (XPS, and scanning electron microscopy (SEM techniques, and then used as an adsorbent for heavy metal ions removal in water treatment. This study illustrates that the metal-organic frameworks may be suitable precursors for the fabrication of metal oxides nanomaterials with large specific surface area, and the prepared porous γ-Fe2O3 exhibits a superior adsorption performance for As(V and As(III ions removal in water treatment.

  7. Separation of some metal ions using coupled transport supported liquid membranes

    International Nuclear Information System (INIS)

    Chaudhary, M.A.

    1993-01-01

    Liquid membrane extraction processes has become very popular due to their superiority in many ways over other separation techniques. In coupled transport membranes the metal ions can be transported across the membrane against their concentration gradient under the influence of chemical potential difference. Liquid membranes consisting of a carrier-cum-diluent, supported in microporous polymeric hydrophobic films have been studied for transport of metal ions like U(VI), Cr(VI), Be(II), V(V), Ti(IV), Zn(II), Cd(II), Hf(IV), W(VI), and Co(II). The present paper presents basic data with respect to flux and permeabilities of these metal ions across membranes based on experimental results and theoretical equations, using different carriers and diluents and provides a brief reference to possibility of such membranes for large scale applications. (author)

  8. Linen Fire as Biosorbent to Remove Heavy Metal Ions From Wastewater Modeling

    OpenAIRE

    Ildar G. Shaikhiev

    2014-01-01

    The possibility of using linen fires – lnopererabotk i waste as a sorption material for the extraction of heavy metal ions from wastewater modeling. It is shown that treatment with acid solutions linen fires a low concentration increases the surface area of linen fires and thus sorption capacity for heavy metal ions. The values of the maximum sorption capacity ions Fe (III), Co (II), Ni (II) and Zn (II) under static and dynamic conditions. IR spectroscopy...

  9. High intensity metallic ion beams from an ecr ion source at GANIL

    International Nuclear Information System (INIS)

    Leherissier, P.; Barue, C.; Canet, C.; Dupuis, M.; Flambard, J.L.; Gaubert, G.; Gibouin, S.; Huguet, Y.; Jardin, P.; Lecesne, N.; Lemagnen, F.; Leroy, R.; Pacquet, J.Y.; Pellemoine-Landre, F.; Rataud, J.P.; Jaffres, P.A.

    2001-01-01

    In the recent years, progress concerning the production of high intensity of metallic ions beams ( 58 Ni, 48 Ca, 76 Ge) at Ganil have been performed. The MIV0C method has been successfully used to produce a high intensity nickel beam with the ECR4 ion source: 20 eμA of 58 Ni 11+ at 24 kV extraction voltage. This beam has been maintained for 8 days and accelerated up to 74.5 MeV/u by our cyclotrons with a mean intensity of 0.13 pμA on target. This high intensity, required for experiment, led to the discovery of the doubly magic 48 Ni isotope. The oven method has been first tested with natural metallic calcium on the ECR4 ion source, then used to produce a high power beam (740 W on target i.e. 0.13 pμA accelerated up to 60 MeV/u) of 48 Ca still keeping a low consumption (0.09 mg/h). A germanium beam is now under development, using the oven method with germanium oxide. The ionization efficiencies have been measured and compared. (authors)

  10. Observation of self-sputtering in energetic condensation of metal ions

    International Nuclear Information System (INIS)

    Anders, Andre

    2004-01-01

    The condensation of energetic metal ions on a surface may cause self-sputtering even in the absence of substrate bias. Charge-state-averaged self-sputtering yields were determined for both zirconium and gold ions generated by a cathodic vacuum arc. Films were deposited on differently biased substrates exposed to streaming Zr and Au vacuum arc plasma. The self-sputtering yields for both metals were estimated to be about 0.05 in the absence of bias, and exceeding 0.5 when bias reached-50 V. These surprisingly high values can be reconciled with binary collision theory and molecular dynamics calculations taking high the kinetic and potential energy of vacuum arc ions into account

  11. Alkali-Metal-Ion-Functionalized Graphene Oxide as a Superior Anode Material for Sodium-Ion Batteries.

    Science.gov (United States)

    Wan, Fang; Li, Yu-Han; Liu, Dai-Huo; Guo, Jin-Zhi; Sun, Hai-Zhu; Zhang, Jing-Ping; Wu, Xing-Long

    2016-06-06

    Although graphene oxide (GO) has large interlayer spacing, it is still inappropriate to use it as an anode for sodium-ion batteries (SIBs) because of the existence of H-bonding between the layers and ultralow electrical conductivity which impedes the Na(+) and e(-) transformation. To solve these issues, chemical, thermal, and electrochemical procedures are traditionally employed to reduce GO nanosheets. However, these strategies are still unscalable, consume high amounts of energy, and are expensive for practical application. Here, for the first time, we describe the superior Na storage of unreduced GO by a simple and scalable alkali-metal-ion (Li(+) , Na(+) , K(+) )-functionalized process. The various alkali metals ions, connecting with the oxygen on GO, have played different effects on morphology, porosity, degree of disorder, and electrical conductivity, which are crucial for Na-storage capabilities. Electrochemical tests demonstrated that sodium-ion-functionalized GO (GNa) has shown outstanding Na-storage performance in terms of excellent rate capability and long-term cycle life (110 mAh g(-1) after 600 cycles at 1 A g(-1) ) owing to its high BET area, appropriate mesopore, high degree of disorder, and improved electrical conductivity. Theoretical calculations were performed using the generalized gradient approximation (GGA) to further study the Na-storage capabilities of functionalized GO. These calculations have indicated that the Na-O bond has the lowest binding energy, which is beneficial to insertion/extraction of the sodium ion, hence the GNa has shown the best Na-storage properties among all comparatives functionalized by other alkali metal ions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Divalent metal ion removal from aqueous solution by acid-treated ...

    African Journals Online (AJOL)

    ions determined from the Langmuir isotherm showed that C. indica had the largest sorption capacity for Pb2+ ions and the least sorption for Ni2+. The results also showed that garlic-treatment of C. indica biomass enhanced its sorption capacity for the divalent metal ions, with the enhancement factor varying from 1.22 to 1.44 ...

  13. The effect of magnetite nanoparticles synthesis conditions on their ability to separate heavy metal ions

    Directory of Open Access Journals (Sweden)

    Bobik Magdalena

    2017-06-01

    Full Text Available Magnetite nanoparticles have become a promising material for scientific research. Among numerous technologies of their synthesis, co-precipitation seems to be the most convenient, less time-consuming and cheap method which produces fine and pure iron oxide particles applicable to environmental issues. The aim of the work was to investigate how the co-precipitation synthesis parameters, such as temperature and base volume, influence the magnetite nanoparticles ability to separate heavy metal ions. The synthesis were conducted at nine combinations of different ammonia volumes - 8 cm3, 10 cm3, 15 cm3 and temperatures - 30°C, 60°C, 90°C for each ammonia volume. Iron oxides synthesized at each combination were examined as an adsorbent of seven heavy metals: Cr(VI, Pb(II, Cr(III, Cu(II, Zn(II, Ni(II and Cd(II. The representative sample of magnetite was characterized using XRD, SEM and BET methods. It was observed that more effective sorbent for majority of ions was produced at 30°C using 10 cm3 of ammonia. The characterization of the sample produced at these reaction conditions indicate that pure magnetite with an average crystallite size of 23.2 nm was obtained (XRD, the nanosized crystallites in the sample were agglomerated (SEM and the specific surface area of the aggregates was estimated to be 55.64 m2·g-1 (BET. The general conclusion of the work is the evidence that magnetite nanoparticles have the ability to adsorb heavy metal ions from the aqueous solutions. The effectiveness of the process depends on many factors such as kind of heavy metal ion or the synthesis parameters of the sorbent.

  14. Sensitivity to Heavy-Metal Ions of Unfolded Fullerene Quantum Dots

    Directory of Open Access Journals (Sweden)

    Erica Ciotta

    2017-11-01

    Full Text Available A novel type of graphene-like quantum dots, synthesized by oxidation and cage-opening of C60 buckminsterfullerene, has been studied as a fluorescent and absorptive probe for heavy-metal ions. The lattice structure of such unfolded fullerene quantum dots (UFQDs is distinct from that of graphene since it includes both carbon hexagons and pentagons. The basic optical properties, however, are similar to those of regular graphene oxide quantum dots. On the other hand, UFQDs behave quite differently in the presence of heavy-metal ions, in that multiple sensitivity to Cu2+, Pb2+ and As(III was observed through comparable quenching of the fluorescent emission and different variations of the transmittance spectrum. By dynamic light scattering measurements and transmission electron microscope (TEM images we confirmed, for the first time in metal sensing, that this response is due to multiple complexation and subsequent aggregation of UFQDs. Nonetheless, the explanation of the distinct behaviour of transmittance in the presence of As(III and the formation of precipitate with Pb2+ require further studies. These differences, however, also make it possible to discriminate between the three metal ions in view of the implementation of a selective multiple sensor.

  15. Effect Of Metal Ions On Triphenylmethane Dye Decolorization By Laccase From Trametes Versicolor

    Directory of Open Access Journals (Sweden)

    Chmelová Daniela

    2015-12-01

    Full Text Available The aim of this study was investigate the influence of different metal ions on laccase activity and triphenylmethane dye decolorization by laccase from white-rot fungus Trametes versicolor. Laccase activity was inhibited by monovalent ions (Li+, Na+, K+ and Ag+ but the presence of divalent ions increased laccase activity at the concentration of 10 mmol/l. The effect of metal ions on decolorization of triphenylmethane dyes with different structures namely Bromochlorophenol Blue, Bromophenol Blue, Bromocresol Blue and Phenol Red was tested. The presence of metal ions (Na+, K+, Mg2+, Ca2+, Ba2+, Mn2+, Zn2+ slightly decreased triphenylmethane dye decolorization by laccase from T. versicolor except Na+ and Mg2+, which caused the increase of decolorization for all tested dyes. Decolorization of selected dyes showed that the presence of low-molecular-weight compounds is necessary for effective decolorization. Hydroxybenzotriazole (HBT is the most frequently used. Although HBT belongs to most frequently used redox mediator and generally increase decolorization efficiency, so its presence decreased decolorization percentage of Bromophenol Blue and Bromochlorophenol Blue, the influence of metal ions to dye decolorization by laccase has the similar course with or without presence of redox mediator HBT.

  16. Studies on the competitive sorption of divalent metal ions to natural soil samples using a multitracer technique

    International Nuclear Information System (INIS)

    Fujiyoshi, R.; Hirashima, H.; Sawamura, S.

    1997-01-01

    Speciation of minor or trace amount of pollutants, such as heavy metals and radionuclides released from atmospheric precipitation and water streams have been studied in order to elucidate their fates in the environment through 'in situ' observations or laboratory experiments. The authors have investigated sorption of heavy metals on various natural samples radiometrically ( 65 Zn as a tracer). A sequential extraction technique was found to be very effective to elucidate possible scavengers (minerals) of heavy metals in some cases. A sediment with low CEC does not sorb Zn (ii) ions to a great extent. It is thus considered that the zinc sorption occurs competitively with protons present in the aqueous media. Divalent copper and cadmium ions also behaved similarly to Zn(II), which was obtained electrochemically with the ion selective electrodes of Cu(II) and Cd(II). This time the authors investigated the competitive sorption of Mn(ii) and Zn(II) to natural soils using a radiotracer technique, which was considered to be useful to evaluate relative importance of the sorption of each metal ion without serious matrix effects. Quite different properties appeared among those metal ions used independently or simultaneously as a tracer. Proton exchange process may be important for the Zn(II) sorption, whereas a solid-solution partition is supposed to control the Mn(ii) uptake, when each of them was examined independently as a sorbate. In contrast, simultaneous use of those tracers to a soil suspension had great effects on the result; the maximum sorption (A m ) of Zn(II) increased, and Mn(II) behaved like a sorbate which tends to occupy specific sites of the soil surfaces. Those results indicate that the sorption of minor and/or trace elements to natural soils would not be evaluated through a series of experiments with a single sorbate

  17. Quantitative description and local structures of trivalent metal ions Eu(III) and Cm(III) complexed with poly-acrylic acid

    International Nuclear Information System (INIS)

    Montavon, G.; Huclier-Markai, S.; Grambow, B.; Bouby, M.; Geckeis, H.; Rabung, T.; Huclier-Markai, S.; Pashalidis, I.; Amekraz, B.; Moulin, C.

    2008-01-01

    The trivalent metal ion (M(III) = Cm, Eu)/poly-acrylic acid (PAA) system was studied in the pH range between 3 and 5.5 for a molar PAA-to-metal ratio above 1. The interaction was studied for a wide range of PAA (0.05 mg L -1 -50 g L -1 ) and metal ion concentrations (2*10 -9 - 10 -3 M). This work aimed at 3 goals (i) to determine the stoichiometry of M(III)-PAA complexes, (ii) to determine the number of complexed species and the local environment of the metal ion, and (iii) to quantify the reaction processes. Asymmetric flow-field-flow fractionation (AsFIFFF) coupled to ICP-MS evidenced that size distributions of Eu-PAA complexes and PAA were identical, suggesting that Eu bound to only one PAA chain. Time-resolved laser fluorescence spectroscopy (TRLFS) measurements performed with Eu and Cm showed a continuous shift of the spectra with increasing pH. The environment of complexed metal ions obviously changes with pH. Most probably, spectral variations arose from conformational changes within the M(Ill)-PAA complex due to pH variation. Complexation data describing the distribution of complexed and free metal ion were measured with Cm by TRLFS. They could be quantitatively described in the whole pH-range studied by considering the existence of only a single complexed species. This indicates that the slight changes in M(III) speciation with pH observed at the molecular level do not significantly affect the intrinsic binding constant. The interaction constant obtained from the modelling must be considered as a mean interaction constant. (authors)

  18. Adsorption of heavy metal ions on molybdenum and molybdenum trioxide from dilute aqueous solution

    International Nuclear Information System (INIS)

    Utsunomiya, Taizo; Hoshino, Yoshio; Sakabe, Ken-ichi

    1984-01-01

    The adsorption of heavy metal ions such as Co(II), Cu(II) and Pb(II) on molybdenum powder has been investigated by the batch technique as a function of soaking time, concentration of heavy metal ions and coexisting salts, pH etc. Molybdenum trioxide was also used as an adsorbent for a comparison to discuss the adsorption mechanism. The amount of these heavy metal ions adsorbed was highly pH and coexisting salts dependent. These adsorbents have features of selective adsorption for Pb(II) and large adsorption rate. The adsorption of heavy metal ions on these adsorbents proceeds independently or concurrently by following complex mechanism; (1) cation exchange reaction by hydroxyl radical on the surface of Mo and MoO 3 is predominant for most of heavy metal ions except Pb(II) [Co(II), Mn(II), Fe(III), Ni(II), Zn(II), Cd(II) and Sr(II)], (2) reduction (electron exchange reaction) to low ionic or metallic state after cation exchange reaction [Cu(II) and Ag(I) on Mo] and (3) formation of a compound [Pb(II) on both Mo and MoO 3 ]. (author)

  19. Inhibition of cellulase-catalyzed lignocellulosic hydrolysis by iron and oxidative metal ions and complexes.

    Science.gov (United States)

    Tejirian, Ani; Xu, Feng

    2010-12-01

    Enzymatic lignocellulose hydrolysis plays a key role in microbially driven carbon cycling and energy conversion and holds promise for bio-based energy and chemical industries. Cellulases (key lignocellulose-active enzymes) are prone to interference from various noncellulosic substances (e.g., metal ions). During natural cellulolysis, these substances may arise from other microbial activities or abiotic events, and during industrial cellulolysis, they may be derived from biomass feedstocks or upstream treatments. Knowledge about cellulolysis-inhibiting reactions is of importance for the microbiology of natural biomass degradation and the development of biomass conversion technology. Different metal ions, including those native to microbial activity or employed for biomass pretreatments, are often tested for enzymatic cellulolysis. Only a few metal ions act as inhibitors of cellulases, which include ferrous and ferric ions as well as cupric ion. In this study, we showed inhibition by ferrous/ferric ions as part of a more general effect from oxidative (or redox-active) metal ions and their complexes. The correlation between inhibition and oxidation potential indicated the oxidative nature of the inhibition, and the dependence on air established the catalytic role that iron ions played in mediating the dioxygen inhibition of cellulolysis. Individual cellulases showed different susceptibilities to inhibition. It is likely that the inhibition exerted its effect more on cellulose than on cellulase. Strong iron ion chelators and polyethylene glycols could mitigate the inhibition. Potential microbiological and industrial implications of the observed effect of redox-active metal ions on enzymatic cellulolysis, as well as the prevention and mitigation of this effect in industrial biomass conversion, are discussed.

  20. Investigation the effects of metallic substrate surfaces due to ion-plasma treatment

    International Nuclear Information System (INIS)

    Shulaev, V.M.; Taran, V.S.; Timoshenko, A.I.; Gasilin, V.V.

    2011-01-01

    It has been found correlation between modification effects and duration of ion-plasma cleaning the substrate surface with titanium ions. Experiments were carried out using serial vacuum-arc equipment ''Bulat-6'' at the stationary mode in non-filtered titanium plasma, which contained considerable quantity of evaporated material droplets. The polished cylinder substrates (diameter and height 9,14,20 mm) have been treated. The substrates were manufactured of stainless steel 12X18H10T and non-oxygen copper M00b. The substrates surface roughness after ion-plasma treatment has been investigated with electron microscope JEOL JSM-840 and optic interference non-contact profilograph- profilometer ''Micron-alpha''. According obtained results the surface of copper and stainless steel substrates has been treated to intensive modification, i.e. substrate surface after treatment significantly differs from initial one. During final ion-plasma treatment a number of effects occur: purification from surface oxides is accompanied with metallic surface ''contamination'' by the cathode material macrodroplets, surface micromelting accompanied by roughness increase, the surface layer annealing with noticeable decrease of hardness.

  1. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuxiao; Zhang, Jianming [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Huang, Hui [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. Black-Right-Pointing-Pointer MPCS was covalently modified by cysteine (MPCS-CO-Cys). Black-Right-Pointing-Pointer MPCS-CO-Cys was first time used in electrochemical detection of heavy metal ions. Black-Right-Pointing-Pointer Heavy metal ions such as Pb{sup 2+} and Cd{sup 2+} can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  2. Equilibrium and kinetics studies of metal ion adsorption on dyed ...

    African Journals Online (AJOL)

    GREGO

    2007-04-02

    Apr 2, 2007 ... Initial concentration of Cu(II) ions = 20 mg/l, adsorbent dose = 1.0 g. Table 2 Experiment Data of ... diffusivity of the metal ion would be independent of the extent of sorption .... exchange and adsorption. Equilibrium parameter.

  3. Cobalt- and Cadmium-Based Metal-Organic Frameworks as High-Performance Anodes for Sodium Ion Batteries and Lithium Ion Batteries.

    Science.gov (United States)

    Dong, Caifu; Xu, Liqiang

    2017-03-01

    Two multifunctional metal-organic frameworks (MOFs) with the same coordination mode, [Co(L)(H 2 O)] n ·2nH 2 O [defined as "Co(L) MOF"] and [Cd(L)(H 2 O)] n ·2nH 2 O [defined as "Cd(L) MOF"] (L = 5-aminoisophthalic acid) have been fabricated via a simple and versatile scalable solvothermal approach at 85 °C for 24 h. The relationship between the structure of the electrode materials (especially the coordination water and different metal ions) and the electrochemical properties of MOFs have been investigated for the first time. And then the possible electrochemical mechanisms of the electrodes have been studied and proposed. In addition, MOFs/RGO hybrid materials were prepared via ball milling, which demonstrated better electrochemical performances than those of individual Co(L) MOF and Cd(L) MOF. For example, when Co(L) MOF/RGO was applied as anode for sodium ion batteries (SIBs), it retained 206 mA h g -1 after 330 cycles at 500 mA g -1 and 1185 mA h g -1 could be obtained after 50 cycles at 100 mA g -1 for lithium-ion batteries (LIBs). The high-discharge capacity, excellent cyclic stability combined with the facile synthesis procedure enable Co(L) MOF- and Cd(L) MOF-based materials to be prospective anode materials for SIBs and LIBs.

  4. Lithium alloys and metal oxides as high-capacity anode materials for lithium-ion batteries

    International Nuclear Information System (INIS)

    Liang, Chu; Gao, Mingxia; Pan, Hongge; Liu, Yongfeng; Yan, Mi

    2013-01-01

    Highlights: •Progress in lithium alloys and metal oxides as anode materials for lithium-ion batteries is reviewed. •Electrochemical characteristics and lithium storage mechanisms of lithium alloys and metal oxides are summarized. •Strategies for improving electrochemical lithium storage properties of lithium alloys and metal oxides are discussed. •Challenges in developing lithium alloys and metal oxides as commercial anodes for lithium-ion batteries are pointed out. -- Abstract: Lithium alloys and metal oxides have been widely recognized as the next-generation anode materials for lithium-ion batteries with high energy density and high power density. A variety of lithium alloys and metal oxides have been explored as alternatives to the commercial carbonaceous anodes. The electrochemical characteristics of silicon, tin, tin oxide, iron oxides, cobalt oxides, copper oxides, and so on are systematically summarized. In this review, it is not the scope to retrace the overall studies, but rather to highlight the electrochemical performances, the lithium storage mechanism and the strategies in improving the electrochemical properties of lithium alloys and metal oxides. The challenges and new directions in developing lithium alloys and metal oxides as commercial anodes for the next-generation lithium-ion batteries are also discussed

  5. Photodetachment of negative ion in a gradient electric field near a metal surface

    International Nuclear Information System (INIS)

    Liu Tian-Qi; Wang De-Hua; Han Cai; Liu Jiang; Liang Dong-Qi; Xie Si-Cheng

    2012-01-01

    Based on closed-orbit theory, the photodetachment of H − in a gradient electric field near a metal surface is studied. It is demonstrated that the gradient electric field has a significant influence on the photodetachment of negative ions near a metal surface. With the increase of the gradient of the electric field, the oscillation in the photodetachment cross section becomes strengthened. Besides, in contrast to the photodetachment of H − near a metal surface in a uniform electric field, the oscillating amplitude and the oscillating region in the cross section of a gradient electric field also become enlarged. Therefore, we can use the gradient electric field to control the photodetachment of negative ions near a metal surface. We hope that our results will be useful for understanding the photodetachment of negative ions in the vicinity of surfaces, cavities, and ion traps. (atomic and molecular physics)

  6. Collision cross sections and equilibrium fractions of ions and atoms in metal vapor targets. Project progress report, June 1, 1979-May 31, 1980

    International Nuclear Information System (INIS)

    Morgan, T.J.

    1980-01-01

    The objective of this program is to measure atomic collision cross sections and equilibrium fractions of ions and atoms in metal vapor targets. The goal is to obtain experimental information on atomic collision processes relevant to the Magnetic Fusion Energy Program. In particular, in connection with the development of double charge exchange D - ion sources, we are measuring D - formation cross sections in alkaline-earth metal vapor targets. During the period covered in this report we have measured electron transfer cross sections for 3-40 keV D + ions and D 0 atoms in collision with calcium vapor

  7. Heavy ion beams from the new Hungarian ECR ion source

    International Nuclear Information System (INIS)

    Biri, S.; Valek, A.; Ditroi, F.; Koivisto, H.; Arje, J.; Stiebing, K.; Schmidt, L.

    1998-01-01

    The first beams of highly charged ions in Hungary were obtained in fall of 1996. The new 14.5 GHz ECR ion source of ATOMKI produced beams of multiply charged ions with remarkable intensities at first experiments. Since then, numerous further developments were carried out. An external electrondonor electrode drastically increased the plasma density and, consequently, the intensity of highly charged ions. These upgrades concentrated mainly on beams from gaseous elements and were carried out by the ECRIS team of ATOMKI. Another series of experiments - ionising from solids - however, was done in the framework of an international collaboration. The first metal ion beam has been extracted from the ECRIS in November 1997 using the known method of Metal Ions from Volatile Compounds (MIVOC). The possibility to put the MIVOC chamber inside the ion source was also tested and the dosing regulation problem of metal vapours inside the ion source was solved. As a result, beams of more than 10 μA of highly charged Fe and Ni ions were produced. (author)

  8. Examining metallic glass formation in LaCe:Nb by ion implantation

    Directory of Open Access Journals (Sweden)

    Sisson Richard

    2017-01-01

    Full Text Available In order to combine niobium (Nb with lanthanum (La and cerium (Ce, Nb ions were deposited within a thin film of these two elements. According to the Hume-Rothery rules, these elements cannot be combined into a traditional crystalline metallic solid. The creation of an amorphous metallic glass consisting of Nb, La, and Ce is then investigated. Amorphous metallic glasses are traditionally made using fast cooling of a solution of molten metals. In this paper, we show the results of an experiment carried out to form a metallic glass by implanting 9 MeV Nb 3+ atoms into a thin film of La and Ce. Prior to implantation, the ion volume distribution is calculated by Monte Carlo simulation using the SRIM tool suite. Using multiple methods of electron microscopy and material characterization, small quantities of amorphous metallic glass are indeed identified.

  9. Study of highly functionalized metal surface treated by plasma ion implantation

    International Nuclear Information System (INIS)

    Ikeyama, Masami; Miyagawa, Soji; Miyagawa, Yoshiko; Nakao, Setsuo; Masuda, Haruho; Saito, Kazuo; Ono, Taizou; Hayashi, Eiji

    2004-01-01

    Technology for processing metal surfaces with hardness, low friction and free from foreign substances was developed with plasma ion implantation. Diamond-like carbon (DLC) coating is a most promising method for realization of hard and smooth metal surface. DLC coating was tested in a metal pipe with 10 mm diameter and 10 cm length by a newly developed plasma ion implantation instrument. The surface coated by DLC was proved to have characteristics equivalent to those prepared with other methods. A computer program simulating a formation process of DLC coating was developed. Experiments for fluorinating the DLC coating surface was performed. (Y. Kazumata)

  10. A study of metallic coatings obtained by electrolysis of molten salts

    International Nuclear Information System (INIS)

    Broc, Michel.

    1978-06-01

    An appropriate technique has been developed for obtaining compact metallic coatings from electrolysis of molten salts. Through the use of this method, it has been possible to produce pure metal deposits which, until now, has been extremely difficult to do. The apparatus used and the main steps of the process such as dehydration of the solvant, degassing of the equipment, and starting of the electrolytic process, are first described. This is followed by a discussion of the deposits of the metals beryllium, uranium, tantalum and tungsten obtained from electrolysis of molten fluorides at temperatures between 600 and 800 0 C. The metal coatings so obtained are homogeneous and show continuity, their thicknesses varying from a few microns to a millimeter or more. They have been studied by measurements. As potential applications of this new technique, one can mention the growth of diffusion barriers and the production of cathodes for thermoionic emission. The method can also be used for electroforming. An intermetallic diffusion between the deposit and the substrate has been observed in some cases. The advantage of the technique of melt electrolysis in obtaining metal coatings of enhanced thicknesses is illustrated by taking the beryllium-nickel system as an example. It is shown that the thickness obtained is proportional to the square root of growth time and is about 6 to 8 times larger than that obtained by conventional techniques [fr

  11. Large pore bi-functionalised mesoporous silica for metal ion pollution treatment

    International Nuclear Information System (INIS)

    Burke, Aoife M.; Hanrahan, John P.; Healy, David A.; Sodeau, John R.; Holmes, Justin D.; Morris, Michael A.

    2009-01-01

    Here we demonstrate aminopropyl and mercatopropyl functionalised and bi-functionalised large pore mesoporous silica spheres to extract various metal ions from aqueous solutions towards providing active sorbents for mitigation of metal ion pollution. Elemental analysis (EA) and FTIR techniques were used to quantify the attachment of the aminopropyl and mercatopropyl functional groups to the mesoporous silica pore wall. Functionalisation was achieved by post-synthesis reflux procedures. For all functionalised silicas the functionalisation refluxing does not alter particle morphology/agglomeration of the particles. It was found that sorptive capacities of the mesoporous silica towards the functional groups were unaffected by co-functionalisation. Powder X-ray diffraction (PXRD) and nitrogen adsorption techniques were used to establish the pore diameters, packing of the pores and specific surface areas of the modified mesoporous silica spheres. Atomic absorption (AA) spectroscopy and inductively coupled plasma-atomic emission spectrometry (ICP-AES) techniques were used to measure the extraction efficiencies of each metal ion species from solution at varying pHs. Maximum sorptive capacities (as metal ions) were determined to be 384 μmol g -1 for Cr, 340 μmol g -1 for Ni, 358 μmol g -1 for Fe, 364 μmol g -1 for Mn and 188 μmol g -1 for Pd

  12. Large pore bi-functionalised mesoporous silica for metal ion pollution treatment

    Energy Technology Data Exchange (ETDEWEB)

    Burke, Aoife M.; Hanrahan, John P. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Environmental Research Institute (ERI), Lee Road, Cork (Ireland); Healy, David A.; Sodeau, John R. [Department of Chemistry, Centre of Research in Atmospheric Chemistry, University College Cork, Cork (Ireland); Holmes, Justin D. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland); Morris, Michael A. [Department of Chemistry, Materials Section and Supercritical Fluid Centre, University College Cork, Cork (Ireland); Environmental Research Institute (ERI), Lee Road, Cork (Ireland); Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2 (Ireland)], E-mail: m.morris@ucc.ie

    2009-05-15

    Here we demonstrate aminopropyl and mercatopropyl functionalised and bi-functionalised large pore mesoporous silica spheres to extract various metal ions from aqueous solutions towards providing active sorbents for mitigation of metal ion pollution. Elemental analysis (EA) and FTIR techniques were used to quantify the attachment of the aminopropyl and mercatopropyl functional groups to the mesoporous silica pore wall. Functionalisation was achieved by post-synthesis reflux procedures. For all functionalised silicas the functionalisation refluxing does not alter particle morphology/agglomeration of the particles. It was found that sorptive capacities of the mesoporous silica towards the functional groups were unaffected by co-functionalisation. Powder X-ray diffraction (PXRD) and nitrogen adsorption techniques were used to establish the pore diameters, packing of the pores and specific surface areas of the modified mesoporous silica spheres. Atomic absorption (AA) spectroscopy and inductively coupled plasma-atomic emission spectrometry (ICP-AES) techniques were used to measure the extraction efficiencies of each metal ion species from solution at varying pHs. Maximum sorptive capacities (as metal ions) were determined to be 384 {mu}mol g{sup -1} for Cr, 340 {mu}mol g{sup -1} for Ni, 358 {mu}mol g{sup -1} for Fe, 364 {mu}mol g{sup -1} for Mn and 188 {mu}mol g{sup -1} for Pd.

  13. Prostate cancer outcome and tissue levels of metal ions

    Science.gov (United States)

    Sarafanov, A.G.; Todorov, T.I.; Centeno, J.A.; MacIas, V.; Gao, W.; Liang, W.-M.; Beam, C.; Gray, Marion A.; Kajdacsy-Balla, A.

    2011-01-01

    BACKGROUNDThere are several studies examining prostate cancer and exposure to cadmium, iron, selenium, and zinc. Less data are available on the possible influence of these metal ions on prostate cancer outcome. This study measured levels of these ions in prostatectomy samples in order to examine possible associations between metal concentrations and disease outcome.METHODSWe obtained formalin fixed paraffin embedded tissue blocks of prostatectomy samples of 40 patients with PSA recurrence, matched 1:1 (for year of surgery, race, age, Gleason grading, and pathology TNM classification) with tissue blocks from 40 patients without recurrence (n = 80). Case–control pairs were compared for the levels of metals in areas adjacent to tumors. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for quantification of Cd, Fe, Zn, and Se.RESULTSPatients with biochemical (PSA) recurrence of disease had 12% lower median iron (95 µg/g vs. 111 µg/g; P = 0.04) and 21% lower zinc (279 µg/g vs. 346 µg/g; P = 0.04) concentrations in the normal-appearing tissue immediately adjacent to cancer areas. Differences in cadmium (0.489 µg/g vs. 0.439 µg/g; 4% higher) and selenium (1.68 µg/g vs. 1.58 µg/g; 5% higher) levels were not statistically significant in recurrence cases, when compared to non-recurrences (P = 0.40 and 0.21, respectively).CONCLUSIONSThere is an association between low zinc and low iron prostate tissue levels and biochemical recurrence in prostate cancer. Whether these novel findings are a cause or effect of more aggressive tumors, or whether low zinc and iron prostatic levels raise implications for therapy, remains to be investigated. 

  14. The influence of heavy metals on the production of extracellular polymer substances in the processes of heavy metal ions elimination.

    Science.gov (United States)

    Mikes, J; Siglova, M; Cejkova, A; Masak, J; Jirku, V

    2005-01-01

    Wastewaters from a chemical industry polluted by heavy metal ions represent a hazard for all living organisms. It can mean danger for ecosystems and human health. New methods are sought alternative to traditional chemical and physical processes. Active elimination process of heavy metals ions provided by living cells, their components and extracellular products represents a potential way of separating toxic heavy metals from industrial wastewaters. While the abilities of bacteria to remove metal ions in solution are extensively used, fungi have been recognized as a promising kind of low-cost adsorbents for removal of heavy-metal ions from aqueous waste sources. Yeasts and fungi differ from each other in their constitution and in their abilities to produce variety of extracellular polymeric substances (EPS) with different mechanisms of metal interactions. The accumulation of Cd(2+), Cr(6+), Pb(2+), Ni(2+) and Zn(2+) by yeasts and their EPS was screened at twelve different yeast species in microcultivation system Bioscreen C and in the shaking Erlenmayer's flasks. This results were compared with the production of yeast EPS and the composition of yeast cell walls. The EPS production was measured during the yeast growth and cell wall composition was studied during the cultivations in the shaking flasks. At the end of the process extracellular polymers and their chemical composition were isolated and amount of bound heavy metals was characterized. The variable composition and the amount of the EPS were found at various yeast strains. It was influenced by various compositions of growth medium and also by various concentrations of heavy metals. It is evident, that the amount of bound heavy metals was different. The work reviews the possibilities of usage of various yeast EPS and components of cell walls in the elimination processes of heavy metal ions. Further the structure and properties of yeasts cell wall and EPS were discussed. The finding of mechanisms mentioned

  15. Metal ion extractant in microemulsions: where solvent extraction and surfactant science meet

    International Nuclear Information System (INIS)

    Bauer, C.

    2011-01-01

    The presented work describes the supramolecular structure of mixtures of a hydrophilic surfactant n-octyl-beta-glucoside (C8G1), and the hydrophobic metal ion extractant tributylphosphate (TBP) in n-dodecane/water as well as in the presence of salts. In the first part, basic solvent extraction system, composed of water, oil and extractant, will be introduced. The focus, however, lies on the extraction of multivalent metal ions from the aqueous phase. During this extraction process and in the following thermodynamic equilibrium, aggregation and phase transition in supramolecular assemblies occur, which are already described in literature. Notably, these reports rest on individual studies and specific conclusions, while a general concept is still missing. We therefore suggest the use of generalized phase diagrams to present the physico-chemical behaviour of (amphiphilic) extractant systems. These phase diagrams facilitated the development of a thermodynamic model based on molecular geometry and packing of the extractant molecules in the oil phase. As a result, we are now in the position to predict size and water content of extractant aggregates and, thus, verify the experimental results by calculation.Consequently, the second part presents a systematic study of the aqueous and organic phase of water/C8G1 and water/oil/TBP mixtures. The focus lies on understanding the interaction between metal ions and both amphiphilic molecules by means of small angle x-ray scattering (SAXS), dynamic light scattering (DLS) and UV-Vis spectroscopy. We confirmed the assumption that extraction of metal ions is driven by TBP, while C8G1 remains passive. In the third and last part, microemulsions of C8G1, TBP, water (and salt) and n-dodecane are characterized by small angle neutron scattering (SANS), and chemical analytics (Karl Fischer, total organic carbon, ICP-OES,...). The co-surfactant behaviour of TBP was highlighted by comparison to the classical n-alcohol (4≤n≤8) co

  16. Enhancing Hydrogen Diffusion in Silica Matrix by Using Metal Ion Implantation to Improve the Emission Properties of Silicon Nanocrystals

    Directory of Open Access Journals (Sweden)

    J. Bornacelli

    2014-01-01

    Full Text Available Efficient silicon-based light emitters continue to be a challenge. A great effort has been made in photonics to modify silicon in order to enhance its light emission properties. In this aspect silicon nanocrystals (Si-NCs have become the main building block of silicon photonic (modulators, waveguide, source, and detectors. In this work, we present an approach based on implantation of Ag (or Au ions and a proper thermal annealing in order to improve the photoluminescence (PL emission of Si-NCs embedded in SiO2. The Si-NCs are obtained by ion implantation at MeV energy and nucleated at high depth into the silica matrix (1-2 μm under surface. Once Si-NCs are formed inside the SiO2 we implant metal ions at energies that do not damage the Si-NCs. We have observed by, PL and time-resolved PL, that ion metal implantation and a subsequent thermal annealing in a hydrogen-containing atmosphere could significantly increase the emission properties of Si-NCs. Elastic Recoil Detection measurements show that the samples with an enhanced luminescence emission present a higher hydrogen concentration. This suggests that ion metal implantation enhances the hydrogen diffusion into silica matrix allowing a better passivation of surface defects on Si NCs.

  17. DFT study of the interaction between DOTA chelator and competitive alkali metal ions.

    Science.gov (United States)

    Frimpong, E; Skelton, A A; Honarparvar, B

    2017-09-01

    1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetracetic acid (DOTA) is an important chelator for radiolabeling of pharmaceuticals. The ability of alkali metals found in the body to complex with DOTA and compete with radio metal ions can alter the radiolabeling process. Non-covalent interactions between DOTA complexed with alkali metals Li + , Na + , K + and Rb + , are investigated with density functional theory using B3LYP and ωB97XD functionals. Conformational possibilities of DOTA were explored with a varying number of carboxylic pendant arms of DOTA in close proximity to the ions. It is found that the case in which four arms of DOTA are interacting with ions is more stable than other conformations. The objective of this study is to explore the electronic structure properties upon complexation of alkali metals Li + Na + , K + and Rb + with a DOTA chelator. Interaction energies, relaxation energies, entropies, Gibbs free energies and enthalpies show that the stability of DOTA, complexed with alkali metals decreases down the group of the periodic table. Implicit water solvation affects the complexation of DOTA-ions leading to decreases in the stability of the complexes. NBO analysis through the natural population charges and the second order perturbation theory, revealed a charge transfer between DOTA and alkali metals. Conceptual DFT-based properties such as HOMO/LUMO energies, ΔE HOMO-LUMO and chemical hardness and softness indicated a decrease in the chemical stability of DOTA-alkali metal complexes down the alkali metal series. This study serves as a guide to researchers in the field of organometallic chelators, particularly, radiopharmaceuticals in finding the efficient optimal match between chelators and various metal ions. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Effect of ion irradiation on tensile ductility, strength and fictive temperature in metallic glass nanowires

    International Nuclear Information System (INIS)

    Magagnosc, D.J.; Kumar, G.; Schroers, J.; Felfer, P.; Cairney, J.M.; Gianola, D.S.

    2014-01-01

    Ion irradiation of thermoplastically molded Pt 57.5 Cu 14.3 Ni 5.7 P 22.5 metallic glass nanowires is used to study the relationship between glass structure and tensile behavior across a wide range of structural states. Starting with the as-molded state of the glass, ion fluence and irradiated volume fraction are systematically varied to rejuvenate the glass, and the resulting plastic behavior of the metallic glass nanowires probed by in situ mechanical testing in a scanning electron microscope. Whereas the as-molded nanowires exhibit high strength, brittle-like fracture and negligible inelastic deformation, ion-irradiated nanowires show tensile ductility and quasi-homogeneous plastic deformation. Signatures of changes to the glass structure owing to ion irradiation as obtained from electron diffraction are subtle, despite relatively large yield strength reductions of hundreds of megapascals relative to the as-molded condition. To reconcile changes in mechanical behavior with glass properties, we adapt previous models equating the released strain energy during shear banding to a transit through the glass transition temperature by incorporating the excess enthalpy associated with distinct structural states. Our model suggests that ion irradiation increases the fictive temperature of our glass by tens of degrees – the equivalent of many orders of magnitude change in cooling rate. We further show our analytical description of yield strength to quantitatively describe literature results showing a correlation between severe plastic deformation and hardness in a single glass system. Our results highlight not only the capacity for room temperature ductile plastic flow in nanoscaled metallic glasses, but also processing strategies capable of glass rejuvenation outside of the realm of traditional thermal treatments

  19. Tailoring of the PS surface with low energy ions: Relevance to growth and adhesion of noble metals

    International Nuclear Information System (INIS)

    Zaporojtchenko, V.; Zekonyte, J.; Wille, S.; Schuermann, U.; Faupel, F.

    2005-01-01

    Ion-polymer interaction induces different phenomena in the near surface layer of polymers, and promotes its adhesion to metals. Using XPS, TEM and AFM, polystyrene surface was examined after 1 keV ion-beam treatments with oxygen, nitrogen and argon ions in the ion fluence range from 10 12 to 10 16 cm -2 to clarify the following points: chemical reaction after treatment in vacuum and after exposure to air, identification of adsorption-relevant species for metal atoms, formation of cross-links in the outermost polymer layer. The early stages of metal-polymer interface formation during metallization play a crucial role in the metal-polymer adhesion. Therefore, the influence of the ion fluence and ion chemistry on the condensation of noble metals, film growth and peel strength were measured. The peel strength showed a maximum at a certain fluence depending on ion chemistry. For example, the surface treatment with very low fluence of oxygen ions improved the adhesion between copper and polystyrene by two orders of magnitude without significantly increasing the surface roughness measured with AFM. The locus of failure changed at the same time from interfacial failure for untreated polymer surfaces to cohesive failure in the polymer for modified surfaces. A multilayer model of the metal-polymer interface after ion treatment is suggested

  20. Selective chelation-supercritical fluid extraction of metal ions from waste materials

    International Nuclear Information System (INIS)

    Wai, C.N.; Laintz, K.E.; Yonker, C.R.

    1993-01-01

    The removal of toxic organics, metals, and radioisotopes from solids or liquids is a major concern in the treatment of industrial and nuclear wastes. For this reason, developing methods for selective separation of toxic metals and radioactive materials from solutions of complex matrix is an important problem in environmental research. Recent developments indicate supercritical fluids are good solvents for organic compounds. Many gases become supercritical fluids under moderate temperatures and pressures. For example, the critical temperature and pressure of carbon dioxide are 31 degrees C and 73 atm, respectively. The high diffusivity, low viscosity, and T-P dependence of solvent strength are some attractive properties of supercritical fluid extraction (SFE). Since CO 2 offers the additional benefits of stability and non-toxicity, the SFE technique avoids generation of organic liquid waste and exposure of personnel to toxic solvents. While direct extraction of metal ions by supercritical fluids is highly inefficient, these ions when complexed with organic ligands become quite soluble in supercritical fluids. Specific ligands can be used to achieve selective extraction of metal ions in this process. After SFE, the fluid phase can be depressurized for precipitation of the metal chelates and recycled. The ligand can also be regenerated for repeated use. The success of this selective chelation-supercritical fluid extraction (SC-SFE) process depends on a number of factors including the efficiencies of the selective chelating agents, solubilities of metal chelates in supercritical fluids, rate of extraction, ease of regeneration of the ligands, etc. In this report, the authors present recent results on the studies of the solubilities of metal chelates in supercritical CO 2 , experimental ions from aqueous solution, and the development of selective chelating agents (ionizable crown ethers) for the extraction of lanthanides and actinides

  1. Selective recognition by novel calix system: ICT based chemosensor for metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Bhatt, Keyur D.; Makwana, Bharat A.; Vyas, Disha J.; Mishra, Divya R.; Jain, Vinod K., E-mail: drvkjain@hotmail.com

    2014-02-15

    A new calix[4]pyrrole derivative bearing four dansyl groups through hydroxyl groups has been synthesized and duly characterized by FT-IR, NMR and ESI-MS. Tetra dansylated calix[4]pyrrole (TDCP) shows selective behavior for U(VI), Th(IV) and Fe(III) ions among all other metal ions, e.g. Li(I), Na(I), K(I), Ca(II), Ni(II), Cd(II), Cu(II), Zn(II), Pb(II), Hg(II) and Ag(I), in the absorption spectra as well as in the emission spectra. The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. The binding constants, stoichiometry and quantum yields have been determined. The mechanism of quenching by Stern–Vohmer equation has also been discussed. -- highlights: • A new selective turn-off fluorescent sensor i.e. tetra dansylated calix[4]pyrrole (TDCP) was synthesized and characterized. • The sensor shows selective behavior for U(VI), Th(IV) and Fe(III) ions among various other metal ions. • The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. • The sensor binds metal ions in 1:1 stoichiometry with good binding constant.

  2. Selective recognition by novel calix system: ICT based chemosensor for metal ions

    International Nuclear Information System (INIS)

    Bhatt, Keyur D.; Makwana, Bharat A.; Vyas, Disha J.; Mishra, Divya R.; Jain, Vinod K.

    2014-01-01

    A new calix[4]pyrrole derivative bearing four dansyl groups through hydroxyl groups has been synthesized and duly characterized by FT-IR, NMR and ESI-MS. Tetra dansylated calix[4]pyrrole (TDCP) shows selective behavior for U(VI), Th(IV) and Fe(III) ions among all other metal ions, e.g. Li(I), Na(I), K(I), Ca(II), Ni(II), Cd(II), Cu(II), Zn(II), Pb(II), Hg(II) and Ag(I), in the absorption spectra as well as in the emission spectra. The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. The binding constants, stoichiometry and quantum yields have been determined. The mechanism of quenching by Stern–Vohmer equation has also been discussed. -- highlights: • A new selective turn-off fluorescent sensor i.e. tetra dansylated calix[4]pyrrole (TDCP) was synthesized and characterized. • The sensor shows selective behavior for U(VI), Th(IV) and Fe(III) ions among various other metal ions. • The absorption spectra show a bathochromic shift while the emission spectra along with red-shift exhibit quenching for U(VI), Th(IV) and Fe(III) ions. • The sensor binds metal ions in 1:1 stoichiometry with good binding constant

  3. Phytoremediation: an overview of metallic ion decontamination from soil

    Energy Technology Data Exchange (ETDEWEB)

    Singh, O.V.; Labana, S.; Pandey, G.; Budhiraja, R.; Jain, R.K. [Inst. of Microbial Technology, Chandigarh (India)

    2003-07-01

    In recent years, phytoremediation has emerged as a promising ecoremediation technology, particularly for soil and water cleanup of large volumes of contaminated sites. The exploitation of plants to remediate soils contaminated with trace elements could provide a cheap and sustainable technology for bioremediation. Many modern tools and analytical devices have provided insight into the selection and optimization of the remediation process by plant species. This review describes certain factors for the phytoremediation of metal ion decontamination and various aspects of plant metabolism during metallic decontamination. Metal-hyperaccumulating plants, desirable for heavily polluted environments, can be developed by the introduction of novel traits into high biomass plants in a transgenic approach, which is a promising strategy for the development of effective phytoremediation technology. The genetic manipulation of a phytoremediator plant needs a number of optimization processes, including mobilization of trace elements/metal ions, their uptake into the root, stem and other viable parts of the plant and their detoxification and allocation within the plant. This upcoming science is expanding as technology continues to offer new, low-cost remediation options. (orig.)

  4. Ion activity and distribution of heavy metals in acid mine drainage polluted subtropical soils

    International Nuclear Information System (INIS)

    Li Yongtao; Becquer, Thierry; Dai Jun; Quantin, Cecile; Benedetti, Marc F.

    2009-01-01

    The oxidative dissolution of mine wastes gives rise to acidic, metal-enriched mine drainage (AMD) and has typically posed an additional risk to the environment. The poly-metallic mine Dabaoshan in South China is an excellent test site to understand the processes affecting the surrounding polluted agricultural fields. Our objectives were firstly to investigate metal ion activity in soil solution, distribution in solid constituents, and spatial distribution in samples, secondly to determine dominant environment factors controlling metal activity in the long-term AMD-polluted subtropical soils. Soil Column Donnan Membrane Technology (SC-DMT) combined with sequential extraction shows that unusually large proportion of the metal ions are present as free ion in the soil solutions. The narrow range of low pH values prevents any pH effects during the binding onto oxides or organic matter. The differences in speciation of the soil solutions may explain the different soil degradation observed between paddy and non-paddy soils. - First evidence of the real free metal ion concentrations in acid mine drainage context in tropical systems

  5. Radiation hardening of metals irradiated by heavy ions

    International Nuclear Information System (INIS)

    Didyk, A.Yu.; Skuratov, V.A.; Mikhajlova, N.Yu.; Regel', V.R.

    1988-01-01

    The damage dose dependence in the 10 -4 -10 -2 dpa region of radiation hardening of Al, V, Ni, Cu irradiated by xenon ions with 124 MeV energy is investigated using the microhardness technique and transmission electron microscope. It is shown that the pure metals radiation hardening is stimulated for defects clusters with the typical size less than 5 nm, as in the case of neutron and the light charge ion irradiation

  6. When is thermodynamics relevant to ion-induced atomic rearrangements in metals

    International Nuclear Information System (INIS)

    Johnson, W.L.; Cheng, Y.T.; Van Rossum, M.; Nicolet, M.A.

    1984-08-01

    The problem of ion-induced mixing of metal bilayers is examined in the limit of heavy metals (Z > 20) and heavy energetic ions (E > 100 keV) and in the absence of delayed effects such as radiation enhanced thermal diffusion. Thermochemical effects are shown to play an important role in biasing the random walk process of mixing. A universal mixing equation is derived which predicts the evolution of the concentration profile as a function of ion dose. Finally, a model is presented which allows one to predict what metallurgical phases are formed during the mixing process. Criteria for amorphous phase formation are particularly emphasized

  7. Renewable Modified Cellulose Bearing Chelating Schiff Base for Adsorptive Removal of Heavy Metal Ions and Antibacterial Action.

    Science.gov (United States)

    Saravanan, R; Ravikumar, L

    2017-07-01

      A novel approach toward chemically modified cellulose bearing active chelating Schiff base with hydroxyl group (Cell-Hy) was synthesized. The modified cellulose was examined for its heavy metal ion uptake potential from aqueous solution. The chemical and structural features of the adsorbent were characterized by Fourier transform infrared spectroscopy (FT-IR), solid state 13C-NMR, Scanning Electron Microscopy (SEM), and energy dispersive analysis of X-ray (EDAX) observations. The experimental conditions and adsorption parameters, including pH, initial metal ion concentration, adsorbent dosage, temperature, and contact time were optimized for the removal of Cu(II) and Pb(II) ions. Kinetic parameters, equilibrium adsorption capacities, and correlation coefficients for pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were carried out. The data obtained from the adsorption of Cu(II) and Pb(II) onto Cell-Hy were subjected to Langmuir and Freundlich isotherm models. Thermodynamic parameters have also been evaluated. The antibacterial activity of modified cellulose was tested toward specific bacterial species.

  8. Redox Active Transition Metal ions Make Melanin Susceptible to Chemical Degradation Induced by Organic Peroxide.

    Science.gov (United States)

    Zadlo, Andrzej; Pilat, Anna; Sarna, Michal; Pawlak, Anna; Sarna, Tadeusz

    2017-12-01

    With aging, retinal pigment epithelium melanosomes, by fusion with the age pigment lipofuscin, form complex granules called melanolipofuscin. Lipofuscin granules may contain oxidized proteins and lipid hydroperoxides, which in melanolipofuscin could chemically modify melanin polymer, while transition metal ions present in melanin can accelerate such oxidative modifications. The aim of this research was to examine the effect of selected transition metal ions on melanin susceptibility to chemical modification induced by the water-soluble tert-butyl hydroperoxide used as an oxidizing agent. Synthetic melanin obtained by DOPA autooxidation and melanosomes isolated from bovine retinal pigment epithelium were analyzed. To monitor tert-butyl hydroperoxide-induced oxidative changes of DMa and BMs, electron paramagnetic resonance spectroscopy, UV-vis absorption spectroscopy, dynamic light scattering, atomic force microscopy and electron paramagnetic resonance oximetry were employed. These measurements revealed that both copper and iron ions accelerated chemical degradation induced by tert-butyl hydroperoxide, while zinc ions had no effect. Strong prooxidant action was detected only in the case of melanosomes and melanin degraded in the presence of iron. It can be postulated that similar chemical processes, if they occur in situ in melanolipofuscin granules of the human retinal pigment epithelium, would modify antioxidant properties of melanin and its reactivity.

  9. Heavy ion time-of-flight ERDA of high dose metal implanted germanium

    Energy Technology Data Exchange (ETDEWEB)

    Dytlewski, N.; Evans, P.J.; Noorman, J.T. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics; Bunder, J. [New South Wales Univ., Wollongong, NSW (Australia). Wollongong Univ. Coll

    1996-12-31

    With the thick Ge substrates used in ion implantation, RBS can have difficulty in resolving the mass-depth ambiguities when analysing materials composed of mixtures of elements with nearly equal masses. Additional, and complimentary techniques are thus required. This paper reports the use of heavy ion time-of-flight elastic recoil detection analysis (ToF- ERDA), and conventional RBS in the analysis of Ge(100) implanted with high dose Ti and Cu ions from a MEWA ion source . Heavy ion ToF ERDA has been used to resolve, and profile the implanted transition metal species, and also to study any oxygen incorporation into the sample resulting from the implantation, or subsequential reactions with air or moisture. This work is part of a study on high dose metal ion implantation of medium atomic weight semiconductor materials. 13 refs., 6 figs.

  10. Heavy ion time-of-flight ERDA of high dose metal implanted germanium

    Energy Technology Data Exchange (ETDEWEB)

    Dytlewski, N; Evans, P J; Noorman, J T [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia); Wielunski, L S [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics; Bunder, J [New South Wales Univ., Wollongong, NSW (Australia). Wollongong Univ. Coll

    1997-12-31

    With the thick Ge substrates used in ion implantation, RBS can have difficulty in resolving the mass-depth ambiguities when analysing materials composed of mixtures of elements with nearly equal masses. Additional, and complimentary techniques are thus required. This paper reports the use of heavy ion time-of-flight elastic recoil detection analysis (ToF- ERDA), and conventional RBS in the analysis of Ge(100) implanted with high dose Ti and Cu ions from a MEWA ion source . Heavy ion ToF ERDA has been used to resolve, and profile the implanted transition metal species, and also to study any oxygen incorporation into the sample resulting from the implantation, or subsequential reactions with air or moisture. This work is part of a study on high dose metal ion implantation of medium atomic weight semiconductor materials. 13 refs., 6 figs.

  11. Towards metals analysis using corona discharge ionization ion mobility spectrometry.

    Science.gov (United States)

    Jafari, Mohammad T; Saraji, Mohammad; Sherafatmand, Hossein

    2016-02-25

    For the first time, the capability of corona discharge ionization ion mobility spectrometry (CD-IMS) in the determination of metal complex was evaluated. The extreme simplicity of dispersive liquid-liquid microextraction (DLLME) coupled to the high sensitivity of CD-IMS measurement could make this combination really useful for simple, rapid, and sensitive determination of metals in different samples. In this regard, mercury, as a model metal, was complexed with diethyldithiocarbamate (DEDTC), and then extracted into the carbon tetrachloride using DLLME. Some parameters affecting the extraction efficiency, including the type and volume of the extraction solvent, the type and volume of the disperser solvent, the concentration of the chelating agent, salt addition and, pH were exhaustively investigated. Under the optimized condition, the enrichment factor was obtained to be 142. The linear range of 0.035-10.0 μg mL(-1) with r(2) = 0.997 and the detection limit of 0.010 μg mL(-1) were obtained. The relative standard deviation values were calculated to be lower than 4% and 8% for intra-day and inter-day, respectively. Finally, the developed method was successfully applied for the extraction and determination of mercury in various real samples. The satisfactory results revealed the capability of the proposed method in trace analysis without tedious derivatization or hydride generation. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Selective fluorescence sensors for detection of nitroaniline and metal Ions based on ligand-based luminescent metal-organic frameworks

    International Nuclear Information System (INIS)

    Yu, Zongchao; Wang, Fengqin; Lin, Xiangyi; Wang, Chengmiao; Fu, Yiyuan; Wang, Xiaojun; Zhao, Yongnan; Li, Guodong

    2015-01-01

    Metal-organic frameworks (MOFs) are porous crystalline materials with high potential for applications in fluorescence sensors. In this work, two solvent-induced Zn(II)–based metal-organic frameworks, Zn_3L_3(DMF)_2 (1) and Zn_3L_3(DMA)_2(H_2O)_3 (2) (L=4,4′-stilbenedicarboxylic acid), were investigated as selective sensing materials for detection of nitroaromatic compounds and metal ions. The sensing experiments show that 1 and 2 both exhibit selective fluorescence quenching toward nitroaniline with a low detection limit. In addition, 1 exhibits high selectivity for detection of Fe"3"+ and Al"3"+ by significant fluorescence quenching or enhancement effect. While for 2, it only exhibits significant fluorescence quenching effect for Fe"3"+. The results indicate that 1 and 2 are both promising fluorescence sensors for detecting and recognizing nitroaniline and metal ions with high sensitivity and selectivity. - Graphical abstract: Two MOFs have been selected as the fluorescence sensing materials for selectively sensing mitroaromatic compounds and metal ions. The high selectivity makes them promising fluorescence sensors for detecting and recognizing nitroaniline and Fe"3"+ or Al"3"+.

  13. Study of highly charged ion production by electron cyclotron resonance ion source. Interactions of Argon 17+ ions with metallic surface at grazing incidence

    International Nuclear Information System (INIS)

    Ban, G.

    1992-04-01

    In this thesis divided in 2 parts, the author first presents the operating of MiniMafios 16/18 GHz ECR ion sources and methods of extracted multicharged ion identification and then, studies the highly charged ion interactions with a metallic surface and the formation of 'hollow atoms'. 556 figs., 17 tabs

  14. Effects of low-energy ion beam bombardment on metal oxides

    International Nuclear Information System (INIS)

    Sullivan, J.L.; Saied, S.O.; Choudhury, T.

    1993-01-01

    This paper describes a study of Ar ion bombardment damage in metal oxides. In the energy range 1 to 5 keV, preferential oxygen removal and reduction of the oxides was found to depend on ion current density, but to be independent of beam energy. (author)

  15. P and Si functionalized MXenes for metal-ion battery applications

    KAUST Repository

    Zhu, Jiajie

    2017-04-10

    MXenes are a family of two-dimensional materials, composed of early transition metal carbides, nitrides, and carbonitrides, with great potential in energy storage systems, in particular in electrodes for Li, Na, K-ion batteries. However, so far the capacities are not competitive. In this context, we investigate P and Si functionalized MXenes for metal-ion battery applications, using first-principles calculations, since P and Si provide reaction products with high ion content. Replacement of the F and OH ligands of Ti2C and V2C with P and Si is demonstrated to be feasible (energy barriers of less than 0.128 eV) and the ion diffusion barriers turn out to be less than 0.32 eV. Importantly, the Li, Na, and K capacities are predicted to be 1767 mAh g−1, 711 mAh g−1, and 711 mAh g−1, respectively, thus being much higher than in the case of F and OH functionalization.

  16. Preferential solvation, ion pairing, and dynamics of concentrated aqueous solutions of divalent metal nitrate salts

    Science.gov (United States)

    Yadav, Sushma; Chandra, Amalendu

    2017-12-01

    We have investigated the characteristics of preferential solvation of ions, structure of solvation shells, ion pairing, and dynamics of aqueous solutions of divalent alkaline-earth metal nitrate salts at varying concentration by means of molecular dynamics simulations. Hydration shell structures and the extent of preferential solvation of the metal and nitrate ions in the solutions are investigated through calculations of radial distribution functions, tetrahedral ordering, and also spatial distribution functions. The Mg2+ ions are found to form solvent separated ion-pairs while the Ca2+ and Sr2+ ions form contact ion pairs with the nitrate ions. These findings are further corroborated by excess coordination numbers calculated through Kirkwood-Buff G factors for different ion-ion and ion-water pairs. The ion-pairing propensity is found to be in the order of Mg(NO3) 2 lead to the presence of substantial dynamical heterogeneity in these solutions of strongly interacting ions. The current study helps us to understand the molecular details of hydration structure, ion pairing, and dynamics of water in the solvation shells and also of ion diffusion in aqueous solutions of divalent metal nitrate salts.

  17. Selective recovery of gold and other metal ions from an algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Darnall, D.W.; Greene, B.; Henzl, M.T.; Hosea, J.M.; McPherson, R.A.; Sneddon, J.; Alexander, M.D.

    1986-02-01

    The authors observed that the pH dependence of the binding of Au/sup 3 +/, Ag/sup +/, and Hg/sup 2 +/ to the algae Chlorella vulgaris is different than the binding of other metal ions. Between pH 5 and 7, a variety of metal ions bind strongly to the cell surface. Most of these algal-bound metal ions can be selectively desorbed by lowering the pH to 2; however, Au/sup 3 +/, Hg/sup 2 +/, and Ag/sup +/ are all bound strongly at pH 2. Addition of a strong ligand at different pHs is required to elute these ions from the algal surface. Algal-bound gold and mercury can be selectively eluted by using mercaptoethanol. An elution scheme is demonstrated for the binding and selective recovery of Cu/sup 2 +/, Zn/sup 2 +/, Au/sup 3 +/, and Hg/sup 2 +/ from an equimolar mixture. 20 references, 2 figures.

  18. Adsorption of Cd(II) Metal Ion on Adsorbent beads from Biomass Saccharomycess cereviceae - Chitosan

    Science.gov (United States)

    Hasri; Mudasir

    2018-01-01

    The adsorbent beads that was preparation from Saccharomycess cereviceae culture strain FN CC 3012 and shrimp shells waste and its application for adsorption of Cd (II) metal ion has been studied. The study start with combination of Saccharomycess cereviceae biomass to chitosan (Sc-Chi), contact time, pH of solution and initial concentration of cations. Total Cd(II) metal ion adsorbed was calculated from the difference of metal ion concentration before and after adsorption by AAS. The results showed that optimum condition for adsorption of Cd(II) ions by Sc-Chi beads was achieved with solution pH of 4, contact time of 60 minutes and initial concentration adsorption 100mg/L. The hydroxyl (-OH) and amino (-NH2) functional groups were believed to be responsible for the adsorption of Cd(II) ions.

  19. Identification of metal ion binding sites based on amino acid sequences.

    Science.gov (United States)

    Cao, Xiaoyong; Hu, Xiuzhen; Zhang, Xiaojin; Gao, Sujuan; Ding, Changjiang; Feng, Yonge; Bao, Weihua

    2017-01-01

    The identification of metal ion binding sites is important for protein function annotation and the design of new drug molecules. This study presents an effective method of analyzing and identifying the binding residues of metal ions based solely on sequence information. Ten metal ions were extracted from the BioLip database: Zn2+, Cu2+, Fe2+, Fe3+, Ca2+, Mg2+, Mn2+, Na+, K+ and Co2+. The analysis showed that Zn2+, Cu2+, Fe2+, Fe3+, and Co2+ were sensitive to the conservation of amino acids at binding sites, and promising results can be achieved using the Position Weight Scoring Matrix algorithm, with an accuracy of over 79.9% and a Matthews correlation coefficient of over 0.6. The binding sites of other metals can also be accurately identified using the Support Vector Machine algorithm with multifeature parameters as input. In addition, we found that Ca2+ was insensitive to hydrophobicity and hydrophilicity information and Mn2+ was insensitive to polarization charge information. An online server was constructed based on the framework of the proposed method and is freely available at http://60.31.198.140:8081/metal/HomePage/HomePage.html.

  20. Ion exchange system design for removal of heavy metals from acid mine drainage wastewater

    Directory of Open Access Journals (Sweden)

    R. S. Sapkal

    2010-11-01

    Full Text Available This paper discusses the methodology used to determine the optimal ion-exchange column size to process all separate batchesof feeds from acid mine drainage wastewater.The optimal design ensures the best utilization of resin material and therefore results in a minimum amount of spent resins.Ion exchanger materials have been studied for removing heavy metals from a metal bearing wastes. For the current treatment,a facility has been designed for the removal of heavy metals from the acid mine drainage (AMD waste by the ion-exchange technology.

  1. Effects of metal ions on growth, β-oxidation system, and thioesterase activity of Lactococcus lactis.

    Science.gov (United States)

    Li, Liang; Ma, Ying

    2014-10-01

    The effects of divalent metal ions (Ca(2+), Mg(2+), Fe(2+), and Cu(2+)) on the growth, β-oxidation system, and thioesterase activity of Lactococcus lactis were investigated. Different metal ions significantly influenced the growth of L. lactis: Ca(2+) and Fe(2+) accelerated growth, whereas Cu(2+) inhibited growth. Furthermore, Mg(2+) inhibited growth of L. lactis at a low concentration but stimulated growth of L. lactis at a high concentration. The divalent metal ions had significant effects on activity of the 4 key enzymes of the β-oxidation system (acyl-CoA dehydrogenase, enoyl-CoA hydratase, L-3-hydroxyacyl-CoA dehydrogenase, and thiolase) and thioesterase of L. lactis. The activity of acyl-CoA dehydrogenases increased markedly in the presence of Ca(2+) and Mg(2+), whereas it decreased with 1 mmol/L Fe(2+) or 12 mmol/L Mg(2+). All the metal ions could induce activity of enoyl-CoA hydratase. In addition, 12 mmol/L Mg(2+) significantly stimulated activity of L-3-hydroxyacyl-CoA dehydrogenase, and all metal ions could induce activity of thiolase, although thiolase activity decreased significantly when 0.05 mmol/L Cu(2+) was added into M17 broth. Inhibition of thioesterase activity by all 4 metal ions could be reversed by 2 mmol/L Ca(2+). These results help us understand the effect of metal ions on the β-oxidation system and thioesterase activity of Lactococcus lactis. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  2. Formation of Negative Metal Ions in a Field-Free Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Larsson, E

    1969-02-15

    A field-free and homogeneous plasma of a large volume is formed by neutron irradiation of {sup 3}He at a density corresponding to NTP and at gas temperatures in the range 300-1600 deg K. The accuracy and ease by which the source density of free electrons can be varied and controlled offers special possibilities to study recombination and attachment phenomena in the absence of diffusion. These possibilities are described and utilized for the study of the effects of mixing the helium gas with metal vapours. Attachment of electrons to neutral metal atoms is found to be the dominant cause of electron removal for metal concentrations above certain limits. Negative metal ions are formed and the rate of their formation was determined to be about 10{sup -13} cm{sup 3}/s. Evidence is also presented, that for such conditions where formation of negative metal ions does not occur, the electrons are lost in electron-ion recombinations, in which the third body is not an electron. No molecular helium spectrum is observed from the plasma when it is very close to spectroscopic purity. Instead, between 3,000-7,000 A only one atomic helium line at 5875 A is observed. The recombination of He{sup +}{sub 2} may therefore be dissociative. A difference in recombination behaviour between {sup 3}He and {sup 4}He at high pressures may therefore exist considering results from previous work on {sup 4}He.

  3. Formation of Negative Metal Ions in a Field-Free Plasma

    International Nuclear Information System (INIS)

    Larsson, E.

    1969-02-01

    A field-free and homogeneous plasma of a large volume is formed by neutron irradiation of 3 He at a density corresponding to NTP and at gas temperatures in the range 300-1600 deg K. The accuracy and ease by which the source density of free electrons can be varied and controlled offers special possibilities to study recombination and attachment phenomena in the absence of diffusion. These possibilities are described and utilized for the study of the effects of mixing the helium gas with metal vapours. Attachment of electrons to neutral metal atoms is found to be the dominant cause of electron removal for metal concentrations above certain limits. Negative metal ions are formed and the rate of their formation was determined to be about 10 -13 cm 3 /s. Evidence is also presented, that for such conditions where formation of negative metal ions does not occur, the electrons are lost in electron-ion recombinations, in which the third body is not an electron. No molecular helium spectrum is observed from the plasma when it is very close to spectroscopic purity. Instead, between 3,000-7,000 A only one atomic helium line at 5875 A is observed. The recombination of He + 2 may therefore be dissociative. A difference in recombination behaviour between 3 He and 4 He at high pressures may therefore exist considering results from previous work on 4 He

  4. Fe3O4/Reduced Graphene Oxide Nanocomposite: Synthesis and Its Application for Toxic Metal Ion Removal

    Directory of Open Access Journals (Sweden)

    Nguyen Thi Vuong Hoan

    2016-01-01

    Full Text Available The synthesis of reduced graphene oxide modified by magnetic iron oxide (Fe3O4/rGO and its application for heavy metals removal were demonstrated. The obtained samples were characterized by X-ray diffraction (XRD, nitrogen adsorption/desorption isotherms, X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectroscopy (FT-IR, and magnetic measurement. The results showed that the obtained graphene oxide (GO contains a small part of initial graphite as well as reduced oxide graphene. GO exhibits very high surface area in comparison with initial graphite. The morphology of Fe3O4/rGO consists of very fine spherical iron nanooxide particles in nanoscale. The formal kinetics and adsorption isotherms of As(V, Ni(II, and Pb(II over obtained Fe3O4/rGO have been investigated. Fe3O4/rGO exhibits excellent heavy metal ions adsorption indicating that it is a potential adsorbent for water sources contaminated by heavy metals.

  5. General Synthesis of Transition-Metal Oxide Hollow Nanospheres/Nitrogen-Doped Graphene Hybrids by Metal-Ammine Complex Chemistry for High-Performance Lithium-Ion Batteries.

    Science.gov (United States)

    Chen, Jiayuan; Wu, Xiaofeng; Gong, Yan; Wang, Pengfei; Li, Wenhui; Mo, Shengpeng; Peng, Shengpan; Tan, Qiangqiang; Chen, Yunfa

    2018-02-09

    We present a general and facile synthesis strategy, on the basis of metal-ammine complex chemistry, for synthesizing hollow transition-metal oxides (Co 3 O 4 , NiO, CuO-Cu 2 O, and ZnO)/nitrogen-doped graphene hybrids, potentially applied in high-performance lithium-ion batteries. The oxygen-containing functional groups of graphene oxide play a prerequisite role in the formation of hollow transition-metal oxides on graphene nanosheets, and a significant hollowing process occurs only when forming metal (Co 2+ , Ni 2+ , Cu 2+ , or Zn 2+ )-ammine complex ions. Moreover, the hollowing process is well correlated with the complexing capacity between metal ions and NH 3 molecules. The significant hollowing process occurs for strong metal-ammine complex ions including Co 2+ , Ni 2+ , Cu 2+ , and Zn 2+ ions, and no hollow structures formed for weak and/or noncomplex Mn 2+ and Fe 3+ ions. Simultaneously, this novel strategy can also achieve the direct doping of nitrogen atoms into the graphene framework. The electrochemical performance of two typical hollow Co 3 O 4 or NiO/nitrogen-doped graphene hybrids was evaluated by their use as anodic materials. It was demonstrated that these unique nanostructured hybrids, in contrast with the bare counterparts, solid transition-metal oxides/nitrogen-doped graphene hybrids, perform with significantly improved specific capacity, superior rate capability, and excellent capacity retention. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Surface layers in the 4A group metals with implanted silicon ions

    International Nuclear Information System (INIS)

    Kovneristyj, Yu.K.; Vavilova, V.V.; Krasnopevtsev, V.V.; Galkin, L.N.; Kudyshev, A.N.; Klechkovskaya, V.V.

    1987-01-01

    A study was made on the change of structure and phase composition of fine near the surface layers of 4A group metals (Hf, Zr, Ti) during ion Si implantation and successive thermal annealing at elevated temperatures. Implantation of Si + ions with 30 or 16 keV energy in Ti, Zr and Hf at room temperature results to amorphization of metal surface layer. The surface hafnium and titanium layer with implanted Si atoms due to interaction with residual atmosphere of oxygen turns during annealing at 870 K to amorphous solid solution of HfO 2m or TiO 2 with Si, preventing further metal oxidation; layers of amorphous alloy are characterized by thermal stability up to 1270 K. Oxidation of the surface amorphous layer in residual oxygen atmosphere and its crystallization in ZrO 2 take place in result of Zr annealing with implanted Si ions at temperature not exceeding 870 K. Similar phenomena are observed in the case of hafnium with implanted oxygen ions or small dose of silicon ions. Thermal stability of amorphous layers produced during ion implantation of Si in Ti, Zr and Hf corresponds to scale resistance of monolithic alloys in Ti-Si, Zr-Si and Hf-Si systems

  7. New Catalytic DNA Biosensors for Radionuclides and Metal ions

    International Nuclear Information System (INIS)

    Lu, Yi

    2003-01-01

    The goals of the project are to develop new catalytic DNA biosensors for simultaneous detection and quantification of bioavailable radionuclides and metal ions, and apply the sensors for on-site, real-time assessment of concentration, speciation and stability of the individual contaminants during and after bioremediation. A negative selection strategy was tested and validated. In vitro selection was shown to yield highly active and specific transition metal ion-dependent catalytic DNA/RNA. A fluorescence resonance energy transfer (FRET) study of in vitro selected DNA demonstrated that the trifluorophore labeled system is a simple and powerful tool in studying complex biomolecules structure and dynamics, and is capable of revealing new sophisticated structural changes. New fluorophore/quenchers in a single fluorosensor yielded improved signal to noise ratio in detection, identification and quantification of metal contaminants. Catalytic DNA fluorescent and colorimetric sensors were shown useful in sensing lead in lake water and in leaded paint. Project results were described in two papers and two patents, and won an international prize

  8. Sorption properties of algae Spirogyra sp. and their use for determination of heavy metal ions concentrations in surface water.

    Science.gov (United States)

    Rajfur, Małgorzata; Kłos, Andrzej; Wacławek, Maria

    2010-11-01

    Kinetics of heavy-metal ions sorption by alga Spirogyra sp. was evaluated experimentally in the laboratory, using both the static and the dynamic approach. The metal ions--Mn(2+), Cu(2+), Zn(2+) and Cd(2+)--were sorbed from aqueous solutions of their salts. The static experiments showed that the sorption equilibria were attained in 30 min, with 90-95% of metal ions sorbed in first 10 min of each process. The sorption equilibria were approximated with the Langmuir isotherm model. The algae sorbed each heavy metal ions proportionally to the amount of this metal ions in solution. The experiments confirmed that after 30 min of exposition to contaminated water, the concentration of heavy metal ions in the algae, which initially contained small amounts of these metal ions, increased proportionally to the concentration of metal ions in solution. The presented results can be used for elaboration of a method for classification of surface waters that complies with the legal regulations. Copyright © 2010 Elsevier B.V. All rights reserved.

  9. General access to metal oxide (Metal = Mn, Co, Ni) double-layer nanospheres for application in lithium ion batteries and supercapacitors

    International Nuclear Information System (INIS)

    Xia, Yuan; Wang, Gang; Zhang, Xing; Wang, Beibei; Wang, Hui

    2016-01-01

    Highlights: • A series of metal oxide double layer nanospheres were prepared. • The obtained materials show excellent performances in lithium ion batteries and supercapacitors. • The unique structure of double layers is beneficial for superior electrochemical performances. - Abstract: In this work, a series of metal oxide double-layer nanospheres (DLNs), such as Mn 2 O 3 , Co 3 O 4 , NiO, NiCo 2 O 4 , and MnCo 2 O 4 have been successfully synthesized through a general template method. The layers of nanospheres were assembled by different nanostructure units and the removing of the SiO 2 template formed a void of several ten nanometers between the double layers, resulting large specific surface areas for them. The energy storage performances of the as-prepared double-layer nanospheres were further investigated in lithium ion battery and supercapacitor systems. Based on their unique nanostructures, the double-layer nanospheres exhibit excellent electrochemical performance with long cycle stability and high specific capacities or capacitances. The best of these, DLNs-NiCo 2 O 4 can deliver a reversible capacity of 1107 mAh g −1 at 0.25C after 200 cycles in lithium ion battery system, and shows a capacitance of 1088 F g −1 with capacitance loss of less than 3% at 5 A g −1 after 5000 cycles in supercapacitors.

  10. [Applications of atomic emission spectrum from liquid electrode discharge to metal ion detection].

    Science.gov (United States)

    Mao, Xiu-Ling; Wu, Jian; Ying, Yi-Bin

    2010-02-01

    The fast and precise detection of metal ion is an important research project concerning studies in diverse academic fields and different kinds of detecting technologies. In the present paper, the authors review the research on atomic emission spectrum based on liquid electrode discharge and its applications in the detection of metal ion. In the first part of this paper the principles and characteristics of the methods based on electrochemistry and spectroscopy were introduced. The methods of ion-selective electrode (ISE), anodic stripping voltammetry, atomic emission spectrum and atomic absorption spectrum were included in this part and discussed comparatively. Then the principles and characteristics of liquid electrode spectra for metal ion detection were introduced. The mechanism of the plasma production and the characteristics of the plasma spectrum as well as its advantages compared with other methods were discussed. Secondly, the authors divided the discharge system into two types and named them single liquid-electrode discharge and double-liquid electrode respectively, according to the number of the liquid electrode and the configuration of the discharge system, and the development as well as the present research status of each type was illustrated. Then the characteristics and configurations of the discharge systems including ECGD, SCGD, LS-APGD and capillary discharge were discussed in detail as examples of the two types. By taking advantage of the technology of atomic emission spectrum based on liquid electrode discharge, the detecting limit of heavy metals such as copper, mercury and argent as well as active metal ions including sodium, potass and magnesium can achieve microg x L(-1). Finally, the advantages and problems of the liquid-electrode discharge applied in detection of metal ion were discussed. And the applications of the atomic emission spectrum based on liquid electrode discharge were prospected.

  11. Metal-ion exchange induced structural transformation as a way of forming novel Ni(II)− and Cu(II)−salicylaldimine structures

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jing-Yun, E-mail: jyunwu@ncnu.edu.tw; Tsai, Chi-Jou; Chang, Ching-Yun; Wu, Yung-Yuan

    2017-02-15

    A Zn(II)−salicylaldimine complex [Zn(L{sup salpyca})(H{sub 2}O)]{sub n} (1, where H{sub 2}L{sup salpyca}=4-hydroxy-3-(((pyridin-2-yl)methylimino)methyl)benzoic acid), with a one-dimensional (1D) chain structure, has been successfully converted to a discrete Ni(II)−salicylaldimine complex [Ni(L{sup salpyca})(H{sub 2}O){sub 3}] (2) and an infinite Cu(II)−salicylaldimine complex ([Cu(L{sup salpyca})]·3H{sub 2}O){sub n} (3) through a metal-ion exchange induced structural transformation process. However, such processes do not worked by Mn(II) and Co(II) ions. Solid-state structure analyses reveal that complexes 1–3 form comparable coordinative or supramolecular zigzag chains running along the crystallographic [201] direction. In addition, replacing Zn(II) ion by Ni(II) and Cu(II) ions caused changes in coordination environment and sphere of metal centers, from a 5-coordinate intermediate geometry of square pyramidal and trigonal bipyramidal in 1 to a 6-coordinate octahedral geometry in 2, and to a 4-coordiante square planar geometry in 3. This study shows that metal-ion exchange serves as a very efficient way of forming new coordination complexes that may not be obtained through direct synthesis. - Graphical abstract: A Zn(II)−salicylaldimine zigzag chain has been successfully converted to a Ni(II)−salicylaldimine supramolecular zigzag chain and a Cu(II)−salicylaldimine coordinative zigzag chain through metal-ion exchange induced structural transformations, which is not achieved by Mn(II) and Co(II) ions.

  12. Animal experimental investigations of the problem of the decorporation of radioactive metal ions

    International Nuclear Information System (INIS)

    Berner, W.

    1973-01-01

    Basically, it is possible to reduce the radiation exposure by excretion intensification of incorporated radioactive materials. Chelate agents have proved to be particularly effective for the accelerated elimination of radioactive metal ions. The kinetics of the distribution and excretion of 57 CoCl 2 , 65 ZnCl 2 and 203 HgCl 2 on the rat under the influence of the chelating agent penicillamin (D-ββ-dimethylcystein) was investigated and the reduction of the radiation exposure in man was calculated from the animal-experimentally gained data. At various times after the incorporation of metal ions, the whole body radioactivity and, after killing the animals, the radioactivity of the organs liver, kidney, spleen, skeleton, muscles and blood, were measured. From the course of the measured radioactivities with time, the biokinetic data of the radioactive metal ions (effective half-lives, selection factors and their components) were determined by means of regression analyses. The chelating agent was applied at different times before or after incorporation of the radioactive metal ions. (EK/LH) [de

  13. Two Divalent Metal Ions and Conformational Changes Play Roles in the Hammerhead Ribozyme Cleavage Reaction

    Science.gov (United States)

    Mir, Aamir; Chen, Ji; Robinson, Kyle; Lendy, Emma; Goodman, Jaclyn; Neau, David; Golden, Barbara L.

    2016-01-01

    The hammerhead ribozyme is a self-cleaving RNA broadly dispersed across all kingdoms of life. Although it was the first of the small, nucleolytic ribozymes discovered, the mechanism by which it catalyzes its reaction remains elusive. The nucleobase of G12 is well positioned to be a general base, but it is unclear if or how this guanine base becomes activated for proton transfer. Metal ions have been implicated in the chemical mechanism, but no interactions between divalent metal ions and the cleavage site have been observed crystallographically. To better understand how this ribozyme functions, we have solved crystal structures of wild-type and G12A mutant ribozymes. We observe a pH-dependent conformational change centered around G12, consistent with this nucleotide becoming deprotonated. Crystallographic and kinetic analysis of the G12A mutant reveals a Zn2+ specificity switch suggesting a direct interaction between a divalent metal ion and the purine at position 12. The metal ion specificity switch and the pH–rate profile of the G12A mutant suggest that the minor imino tautomer of A12 serves as the general base in the mutant ribozyme. We propose a model in which the hammerhead ribozyme rearranges prior to the cleavage reaction, positioning two divalent metal ions in the process. The first metal ion, positioned near G12, becomes directly coordinated to the O6 keto oxygen, to lower the pKa of the general base and organize the active site. The second metal ion, positioned near G10.1, bridges the N7 of G10.1 and the scissile phosphate and may participate directly in the cleavage reaction. PMID:26398724

  14. Metal ion-mediated agonism and agonist enhancement in melanocortin MC1 and MC4 receptors

    DEFF Research Database (Denmark)

    Holst, Birgitte; Elling, Christian E; Schwartz, Thue W

    2002-01-01

    -melanocortin stimulating hormone (alpha-MSH) in the MC1 and MC4 receptors, respectively. In the presence of peptide agonist, Zn(II) acted as an enhancer on both receptors, because it shifted the dose-response curves to the left: most pronounced was a 6-fold increase in alpha-MSH potency on the MC1 receptor. The effect......An endogenous metal-ion site in the melanocortin MC1 and MC4 receptors was characterized mainly in transiently transfected COS-7 cells. ZnCl(2) alone stimulated signaling through the Gs pathway with a potency of 11 and 13 microm and an efficacy of 50 and 20% of that of alpha...... affinities and profiles were similar for a number of the 2,2'-bipyridine and 1,10-phenanthroline analogs in complex with Zn(II) in the MC1 and MC4 receptors. However, the potencies and efficacies of the metal-ion complexes were very different in the two receptors, and close to full agonism was obtained...

  15. Adsorption of heavy metal ions on activated carbon, (5)

    International Nuclear Information System (INIS)

    Yoshida, Hisayoshi; Kamegawa, Katsumi; Arita, Seiji

    1978-01-01

    The adsorption effect of heavy metal ions Cd 2+ , Zn 2+ and Hg 2+ on activated carbon by adding EDTA is reported, utilizing the experimental data. The activated carbons used for the experiment are mostly D, and B, C and F partly. As for the experimental procedure, the solutions of 100 ml which are composed of activated carbon, pH adjusting liquid, EDTA solution and solutions of heavy metals Cd, Zn and Hg, are shaken for 24 hours at 20 deg C, and after the activated carbon is centrifuged and separated for 15 minutes at 3000 rpm, the remaining heavy metal concentrations and pH in the supernatant are measured. The experimental results showed the useful effect on the adsorption of heavy metal ions of Cd, Zn and Hg by adding about 1 mol ratio of (EDTA/heavy metals). The individual experimental results are presented in detail. Concerning the adsorption quantity, 83% of Cd ions remained in the supernatant without addition of EDTA, but less than 1% with addition of about 1 to 5 mol ratio of (EDTA/Cd), and this adsorption effect was almost similar to Zn and Hg, i.e. 100% to 1% in Zn and 70% to 2 or 3% in Hg, under the condition written above. As for the influence of pH on Cd adsorption, the remaining Cd ratio is less than 10%, when pH is 7 to 10.5 at the mol ratio of 1 and 5.5 to 9 at the mol ratio of 10. The adsorption effect was different according to the kinds of activated carbon. The influencing factors for adsorption effect are the concentration of coexisting cations in the solution and the mixing time, etc. The effects of pH on Zn and Hg adsorption were almost similar to Cd. (Nakai, Y.)

  16. The kinetics and thermodynamics of adsorption of heavy metal ions ...

    African Journals Online (AJOL)

    Titanium-Pillared and Un-Pillared bentonite clays were studied in order to evaluate the thermodynamics and kinetics of heavy metal ion removal from aqueous solutions. The results showed that the maximum sorption of Cu, Cd, Hg and Pb ions occurred within 30 minutes. A pseudo-second order kinetic model was used to ...

  17. Vacuum Arc Ion Sources

    CERN Document Server

    Brown, I.

    2013-12-16

    The vacuum arc ion source has evolved into a more or less standard laboratory tool for the production of high-current beams of metal ions, and is now used in a number of different embodiments at many laboratories around the world. Applications include primarily ion implantation for material surface modification research, and good performance has been obtained for the injection of high-current beams of heavy-metal ions, in particular uranium, into particle accelerators. As the use of the source has grown, so also have the operational characteristics been improved in a variety of different ways. Here we review the principles, design, and performance of vacuum arc ion sources.

  18. Characterization and application of Mucuna urens seed husk as novel biosorbent for sequestration of some divalent metal ions from solution

    Directory of Open Access Journals (Sweden)

    Linda Obiageli ELUKE

    2017-07-01

    Full Text Available The utilization of Horse-Eye Bean (Mucuna urens Seed Husk (HEBSH as low cost biosorbent for the abstraction of Co (II, Pb (II and Zn (II ions from water was performed. The biosorbent was characterized by the Fourier Transform Infrared (FTIR spectroscopy, X-ray diffraction (XRD and Scanning Electron Microscopy (SEM. The influence of pH, initial metal ion concentration, biosorbent dosage and contact time on the biosorption was studied. Four isotherm and four kinetic models were used to determine the mechanism of biosorption. FTIR showed the presence of some functional groups such as OH, C=O, C=C, C-O, C-Cl on the surface of HEBSH, while XRD and SEM showed amorphous and non-porous surface structure respectively. Optimum biosorption of the metal ions was obtained at pH 6.0, biosorbent dosage 0.1 g, metal concentration 400 mg/L and contact time of 30, 40, and 60 min for Co (II, Zn (II and Pb (II respectively. The Freundlich gave the best fit for the three metal ions (R2 > 0.95 than the Langmuir, Tempkin and Dubinin-Radushkevich models indicating a multilayer biosorption on a heterogenous surface of HEBSH. Kinetic analysis showed the pseudo first order model presented good fits for Zn (II and Pb (II while the pseudo second order model for Co (II. The initial sorption rate h (mg/g min was 2.35 × 10-3, 2.1 × 10-4 and 6.3 × 10-7 for Co (II, Zn (II and Pb (II ions respectively. Liquid film diffusion was found to be the diffusion mechanism of biosorption rather than the intraparticle diffusion. The experimental investigation showed that HEBSH is effective as a low cost alternative biosorbent for the sequestration of heavy metal ions from aqueous stream.

  19. Recent Progress in Graphite Intercalation Compounds for Rechargeable Metal (Li, Na, K, Al)-Ion Batteries.

    Science.gov (United States)

    Xu, Jiantie; Dou, Yuhai; Wei, Zengxi; Ma, Jianmin; Deng, Yonghong; Li, Yutao; Liu, Huakun; Dou, Shixue

    2017-10-01

    Lithium-ion batteries (LIBs) with higher energy density are very necessary to meet the increasing demand for devices with better performance. With the commercial success of lithiated graphite, other graphite intercalation compounds (GICs) have also been intensively reported, not only for LIBs, but also for other metal (Na, K, Al) ion batteries. In this Progress Report, we briefly review the application of GICs as anodes and cathodes in metal (Li, Na, K, Al) ion batteries. After a brief introduction on the development history of GICs, the electrochemistry of cationic GICs and anionic GICs is summarized. We further briefly summarize the use of cationic GICs and anionic GICs in alkali ion batteries and the use of anionic GICs in aluminium-ion batteries. Finally, we reach some conclusions on the drawbacks, major progress, emerging challenges, and some perspectives on the development of GICs for metal (Li, Na, K, Al) ion batteries. Further development of GICs for metal (Li, Na, K, Al) ion batteries is not only a strong supplement to the commercialized success of lithiated-graphite for LIBs, but also an effective strategy to develop diverse high-energy batteries for stationary energy storage in the future.

  20. Polydopamine-mediated surface-functionalization of graphene oxide for heavy metal ions removal

    International Nuclear Information System (INIS)

    Dong, Zhihui; Zhang, Feng; Wang, Dong; Liu, Xia; Jin, Jian

    2015-01-01

    By utilizing polydopamine (PD) nano-thick interlayer as mediator, polyethylenimine (PEI) brushes with abundant amine groups were grafted onto the surface of PD coated graphene oxide (GO) uniformly via a Michael-Addition reaction and produced a PEI–PD/GO composite nanosheets. The PEI–PD/GO composite exhibited an improved performance for adsorption of heavy metal ions as compared to PEI-coated GO and pure GO. The adsorption capacities for Cu 2+ , Cd 2+ , Pb 2+ , Hg 2+ are up to 87, 106, 197, and 110 mg/g, respectively. To further make the GO based composite operable, PEI–PD/RGO aerogel was prepared through hydrothermal and achieved a high surface area up to 373 m 2 /g. Although the adsorption capacity of PEI–PD/RGO aerogel for heavy metal ions decreases a little as compared to PEI–PD/GO composite dispersion (38, 32, 95, 113 mg/g corresponding to Cu 2+ , Cd 2+ , Pb 2+ , and Hg 2+ , respectively), it could be recycled several times in a simple way by releasing adsorbed metal ions, indicating its potential application for cleaning wastewater. - Graphical abstract: Polyethylenimine (PEI) brushes were grafted onto the surface of graphene oxide (GO) uniformly via a Michael-Addition reaction between the PEI and polydopamine interlayer coated on GO surface. The PEI–PD/GO composite exhibited an improved performance for adsorption of heavy metal ions compared to PEI-coated GO and pure GO. - Highlights: • We prepared polyethylenimine grafted polydopamine-mediated graphene oxide composites. • Introduction of PD layer increases metal ions adsorption capacity. • PEI–PD/RGO aerogel exhibited a superior adsorption performance. • PEI–PD/RGO aerogel can be recycled several times in a simple way

  1. Optical and electronic properties of polyvinyl alcohol doped with pairs of mixed valence metal ions

    International Nuclear Information System (INIS)

    Bulinski, Mircea; Kuncser, Victor; Plapcianu, Carmen; Krautwald, Stefan; Franke, Hilmar; Rotaru, P; Filoti, George

    2004-01-01

    The electronic mechanisms induced by the UV exposure of thin films of polyvinyl alcohol doped with pairs of mixed valence metal ions were studied in relation to their optical behaviour by Moessbauer spectroscopy and optical absorption. The results obtained definitely point to the role of each element from the pair in the electronic mechanism involved, with influence on the optical properties regarding applications in real-time holography and integrated optics

  2. Limitations of disordered carbons obtained from biomass as anodes for real lithium-ion batteries.

    Science.gov (United States)

    Caballero, Alvaro; Hernán, Lourdes; Morales, Julián

    2011-05-23

    Two disordered microporous carbons were obtained from two different types of biomass residues: olive and cherry stones. The former (OS) was activated physically under steam while the latter (CS) chemically with an aqueous solution of ZnCl(2). Their structural and textural properties were studied by X-ray diffraction, scanning electron microscopy, and N(2) adsorption/desorption. Although the samples possess similar textural properties (BET surface areas, micropore surfaces and volumes), the CS carbon is more disordered than the OS carbon. Their electrochemical response in half-cells (CS[OS]/Li) is good; the values are comparable to those obtained from mesocarbon microbeads commonly used in commercial lithium-ion batteries, which consist of highly graphitized carbon. However, cells featuring the OS or CS carbon as anode and LiMn(2)O(4) as cathode perform poorly. Electrochemical activation of the electrodes against lithium metal, a recommended procedure for boosting the electrochemical properties of real lithium-ion batteries, improves cell performance (particularly with OS) but is ultimately ineffective: the delivered average capacity of the activated cell made from OS was less than half its theoretical value. The high irreversible capacity, high polarization between the charge and discharge curves, combined with the presence of various functional groups and the high disorder of the studied carbons which may facilitate side reactions such as electrolyte decomposition, results in a degraded cell performance. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Single-ion triblock copolymer electrolytes based on poly(ethylene oxide) and methacrylic sulfonamide blocks for lithium metal batteries

    Science.gov (United States)

    Porcarelli, Luca; Aboudzadeh, M. Ali; Rubatat, Laurent; Nair, Jijeesh R.; Shaplov, Alexander S.; Gerbaldi, Claudio; Mecerreyes, David

    2017-10-01

    Single-ion conducting polymer electrolytes represent the ideal solution to reduce concentration polarization in lithium metal batteries (LMBs). This paper reports on the synthesis and characterization of single-ion ABA triblock copolymer electrolytes comprising PEO and poly(lithium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethylsulfonyl)imide) blocks, poly(LiMTFSI). Block copolymers are prepared by reversible addition-fragmentation chain transfer polymerization, showing low glass transition temperature (-55 to 7 °C) and degree of crystallinity (51-0%). Comparatively high values of ionic conductivity are obtained (up to ≈ 10-4 S cm-1 at 70 °C), combined with a lithium-ion transference number close to unity (tLi+ ≈ 0.91) and a 4 V electrochemical stability window. In addition to these promising features, solid polymer electrolytes are successfully tested in lithium metal cells at 70 °C providing long lifetime up to 300 cycles, and stable charge/discharge cycling at C/2 (≈100 mAh g-1).

  4. Mutations induced by the action of metal ions in Pisum

    Energy Technology Data Exchange (ETDEWEB)

    von Rosen, G

    1957-01-01

    Simple metal ions may induce both radiomimetic effects and genuine gene mutations of the same type which occurs from ionizing radiation and from treatment with some chemical agencies as e.g., mustard gas. The main material during the experiments has been species of Pisum. The biochemical principle which lies behind these reactions is the complex-forming ability among those reactive bivalent metal elements. The author assumes that interruptions of the chelate formation in the cell synthesis form the real background to the observed activity of the metal ions. The possible role in the evolution of the plant- and animal kingdom and the probable value for plant-breeding of the mutation activity observed are suggested. A new field for mutation experiments may here be opened and the results must hitherto be judged as interesting and promising. 13 references, 7 figures, 4 tables.

  5. Electroplating Ni-63 metal ions in chloride bath on the Cu-plate

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Kwon Mo; Uhm, Young Rang; Son, Kwang Jae; Park, Keun Yung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-05-15

    Ni-63 plating is similar to other electroplating processes that employ soluble metal anodes. The nickel plating solution described by Watts in 1916 eventually replaced all other strategies in use up to that time. Charged Ni ions are formed by sulfate, sulfamate, chloride, and a Watts bath. However, charged Ni-63 ions are formed by dissolving metal Ni-63. Specifically, it requires the passage of direct current (DC) between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. The flow of a DC causes one of the electrodes (the anode) to dissolve and the other electrode (the cathode) to become covered with nickel. The nickel in the solution is present in the form of divalent positively charged ions (Ni{sup 2+}). When the current flows, the positive ions react with two electrons (2e{sup -}) and are converted into metallic nickel (Ni{sup 0}) at the cathode surface. In the present study, we optimize and established process for the electroplating Ni-63 on Cu-plate. Nanocrystalline nickel (Ni) coatings were synthesized by DC electro deposition at a current density of 15 mA/cm{sup 2}. The bath was primarily composed of 0.2 M Ni ions, prepared by dissolving Ni-63 metal particles in HCl. The prototype for electroplating radioactive Ni-63 has been established. The electroplating was carried out by two-step processes such as preparation of ionic solution including Ni-63, and coating processes on the substrate.

  6. Electroplating Ni-63 metal ions in chloride bath on the Cu-plate

    International Nuclear Information System (INIS)

    Yoo, Kwon Mo; Uhm, Young Rang; Son, Kwang Jae; Park, Keun Yung

    2014-01-01

    Ni-63 plating is similar to other electroplating processes that employ soluble metal anodes. The nickel plating solution described by Watts in 1916 eventually replaced all other strategies in use up to that time. Charged Ni ions are formed by sulfate, sulfamate, chloride, and a Watts bath. However, charged Ni-63 ions are formed by dissolving metal Ni-63. Specifically, it requires the passage of direct current (DC) between two electrodes that are immersed in a conductive, aqueous solution of nickel salts. The flow of a DC causes one of the electrodes (the anode) to dissolve and the other electrode (the cathode) to become covered with nickel. The nickel in the solution is present in the form of divalent positively charged ions (Ni 2+ ). When the current flows, the positive ions react with two electrons (2e - ) and are converted into metallic nickel (Ni 0 ) at the cathode surface. In the present study, we optimize and established process for the electroplating Ni-63 on Cu-plate. Nanocrystalline nickel (Ni) coatings were synthesized by DC electro deposition at a current density of 15 mA/cm 2 . The bath was primarily composed of 0.2 M Ni ions, prepared by dissolving Ni-63 metal particles in HCl. The prototype for electroplating radioactive Ni-63 has been established. The electroplating was carried out by two-step processes such as preparation of ionic solution including Ni-63, and coating processes on the substrate

  7. The effect of Nb addition on mechanical properties, corrosion behavior, and metal-ion release of ZrAlCuNi bulk metallic glasses in artificial body fluid.

    Science.gov (United States)

    Qiu, C L; Liu, L; Sun, M; Zhang, S M

    2005-12-15

    Bulk metallic glasses (BMGs) of Zr(65 - x)Nb(x)- Cu(17.5)Ni(10)Al(7.5) with Nb = 0, 2, and 5 at % were prepared by copper mold casting. Compression tests reveal that the two BMGs containing Nb exhibited superior strength and plasticity to the base alloy. The corrosion behavior of the alloys obtained was investigated in artificial body fluid by electrochemical measurements. It was found that the addition of Nb significantly enhanced the corrosion resistance of the Zr-based BMG, as indicated by a remarkable increase in corrosion potential and pitting potential. XPS analysis revealed that the passive film formed after anodic polarization was enriched in aluminum oxide and depleted in phosphate ions for the BMGs containing Nb, which accounts for the improvement of corrosion resistance. On the other hand, metal-ion release of different BMGs were determined in PPb (ng/mL) level with inductively coupled plasma mass spectrometry (ICP-MS) after being immersed in artificial body fluid at 37 degrees C for 20 days. It was found that the addition of Nb considerably reduced the ion release of all kinds of metals of the base system. This is probably attributed to the promoting effect of Nb on a rapid formation of highly protective film.

  8. The main mechanisms of flotation extraction of heavy metal ions out of water solutions

    International Nuclear Information System (INIS)

    Zubareva, G.I.

    2002-01-01

    Flotation extraction of heavy metal ions out of water solutions using reagent EMKO (sodium soaps of vat residues of C grade) is presented. It is established that it is related to hydration energy and stability of sublates being formed. These two parameters affect contrariwise. A difference of molar ratios [EMKO]:[Me] in the course of extracting metals into froth can be explained by their different aggregative state, and a proportion of ionic form of metals and hydroxides being formed. Metal flotation rate is different for each of metal cations to be floated and is dependant on hydrogen ion concentrations [ru

  9. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses

    KAUST Repository

    Zhang, Weipeng; Wang, Yong; Lee, On On; Tian, Renmao; Cao, Huiluo; Gao, Zhaoming; Li, Yongxin; Yu, Li; Xu, Ying; Qian, Pei-Yuan

    2013-01-01

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses.

  10. Adaptation of intertidal biofilm communities is driven by metal ion and oxidative stresses

    KAUST Repository

    Zhang, Weipeng

    2013-11-11

    Marine organisms in intertidal zones are subjected to periodical fluctuations and wave activities. To understand how microbes in intertidal biofilms adapt to the stresses, the microbial metagenomes of biofilms from intertidal and subtidal zones were compared. The genes responsible for resistance to metal ion and oxidative stresses were enriched in both 6-day and 12-day intertidal biofilms, including genes associated with secondary metabolism, inorganic ion transport and metabolism, signal transduction and extracellular polymeric substance metabolism. In addition, these genes were more enriched in 12-day than 6-day intertidal biofilms. We hypothesize that a complex signaling network is used for stress tolerance and propose a model illustrating the relationships between these functions and environmental metal ion concentrations and oxidative stresses. These findings show that bacteria use diverse mechanisms to adapt to intertidal zones and indicate that the community structures of intertidal biofilms are modulated by metal ion and oxidative stresses.

  11. On the single-ion Magnetic Anisotropy of the Rare-Earth Metals

    DEFF Research Database (Denmark)

    Kolmakova, N.P.; Tishin, A.M.; Bohr, Jakob

    1996-01-01

    The temperature dependences of the single-ion magnetic anisotropy constants for Tb and Dy metals are calculated in terms of the multipole moments of the rare-earth ions utilizing the available crystal-field parameters. The results are compared with the existing experimental data....

  12. Adsorbent for metal ions and method of making and using

    Science.gov (United States)

    White, L.R.; Lundquist, S.H.

    1999-08-10

    A method comprises the step of spray-drying a solution or slurry comprising (alkali metal or ammonium) (metal) hexacyanoferrate particles in a liquid, to provide monodisperse, substantially spherical particles in a yield of at least 70 percent of theoretical yield and having a particle size in the range of 1 to 500 micrometers, said particles being active towards Cs ions. The particles, which can be of a single salt or a combination of salts, can be used free flowing, in columns or beds, or entrapped in a nonwoven, fibrous web or matrix or a cast porous membrane, to selectively remove Cs ions from aqueous solutions. 2 figs.

  13. Electron emission during multicharged ion-metal surface interactions

    International Nuclear Information System (INIS)

    Zeijlmans van Emmichoven, P.A.; Havener, C.C.; Hughes, I.G.; Overbury, S.H.; Robinson, M.T.; Zehner, D.M.; Meyer, F.W.

    1992-01-01

    The electron emission during multicharged ion-metal surface interactions will be discussed. The interactions lead to the emission of a significant number of electrons. Most of these electrons have energies below 30 eV. For incident ions with innershell vacancies the emission of Auger electrons that fill these vacancies has been found to occur mainly below the surface. We will present recently measured electron energy distributions which will be used to discuss the mechanisms that lead to the emission of Auger and of low-energy electrons

  14. Global transport and localized layering of metallic ions in the upper atmospherer

    Directory of Open Access Journals (Sweden)

    L. N. Carter

    1999-02-01

    Full Text Available A numerical model has been developed which is capable of simulating all phases of the life cycle of metallic ions, and results are described and interpreted herein for the typical case of Fe+ ions. This cycle begins with the initial deposition of metallics through meteor ablation and sputtering, followed by conversion of neutral Fe atoms to ions through photoionization and charge exchange with ambient ions. Global transport arising from daytime electric fields and poleward/ downward di.usion along geomagnetic field lines, localized transport and layer formation through de- scending convergent nulls in the thermospheric wind field, and finally annihilation by chemical neutralization and compound formation are treated. The model thus sheds new light on the interdependencies of the physical and chemical processes a.ecting atmospheric metallics. Model output analysis confirms the dominant role of both global and local transport to the ion's life cycle, showing that upward forcing from the equatorial electric field is critical to global movement, and that diurnal and semidiurnal tidal winds are responsible for the forma- tion of dense ion layers in the 90±250 km height region. It is demonstrated that the assumed combination of sources, chemical sinks, and transport mechanisms actually produces F-region densities and E-region layer densities similar to those observed. The model also shows that zonal and meridional winds and electric fields each play distinct roles in local transport, whereas the ion distribution is relatively insensitive to reasonable variations in meteoric deposition and chemical reaction rates.Key words. Ionosphere (ion chemistry and composition; ionosphere-atmosphere interactions.

  15. Screen-printed electrodes for environmental monitoring of heavy metal ions: a review

    International Nuclear Information System (INIS)

    Barton, John; González García, María Begoña; Hernández Santos, David; Fanjul-Bolado, Pablo; Ribotti, Alberto; Magni, Paolo; McCaul, Margaret; Diamond, Dermot

    2016-01-01

    Heavy metals such as lead, mercury, cadmium, zinc and copper are among the most important pollutants because of their non-biodegradability and toxicity above certain thresholds. Here, we review methods for sensing heavy metal ions (HMI) in water samples using screen-printed electrodes (SPEs) as transducers. The review (with 107 refs.) starts with an introduction into the topic, and this is followed by sections on (a) mercury-coated SPEs, (b) bismuth-coated SPEs, (c) gold-coated SPEs (d) chemically modified and non-modified carbon SPEs, (e) enzyme inhibition-based SPEs, and (f) an overview of commercially available electrochemical portable heavy metal analyzers. The review reveals the significance of SPEs in terms of decentralized and of in situ analysis of heavy metal ions in environmental monitoring. (author)

  16. The study on the ion exchange behavior of metal ions using composite ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kukki; Lee, Kunjai [Nuclear Engineering Department Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Kim, Youngkyun [Korea Institute of Nuclear Safety, Daejon (Korea, Republic of); Lee, Sangjin; Yang, Hoyeon; Ha, Jonghyun [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2002-04-15

    In this study, a series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. And a separation of metal ions in the liquid radioactive waste have been performed using organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite. The PSF-F (phenol sulphonic formaldehyde-iron ferrite) composite resin prepared by the above method shows stably high removal efficiency to Co(II), Fe, Cs species from wastewater in a wide range of solution pH. The wide range of applicable solution pH (i. e. pH 4.0 to 10.3) implies that the PSF-F composite resin overcomes the limitations of the conventional ferrite process which is practically applicable only to alkaline conditions. The experiment proceeded using batch reactor in a constant temperature with water bath. The experiments divided into three parts. The first one is TG/DTA (Thermogravimetry / Differential Thermal Analysis) which can analyze the trend of pyrolysis of PSF-F ion exchanger. The Second one is equilibrium experiment in which the separation factor of metal ions and Langmuir, Freundlich isotherm was achieved. The last one is kinetics experiment in which the equilibrium reaction time and removal efficiency is estimated.

  17. The study on the ion exchange behavior of metal ions using composite ion exchange resin

    International Nuclear Information System (INIS)

    Kim, Kukki; Lee, Kunjai; Kim, Youngkyun; Lee, Sangjin; Yang, Hoyeon; Ha, Jonghyun

    2002-01-01

    In this study, a series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. And a separation of metal ions in the liquid radioactive waste have been performed using organic-inorganic composite magnetic resin with phenol sulphonic-formaldehyde and freshly formed iron ferrite. The PSF-F (phenol sulphonic formaldehyde-iron ferrite) composite resin prepared by the above method shows stably high removal efficiency to Co(II), Fe, Cs species from wastewater in a wide range of solution pH. The wide range of applicable solution pH (i. e. pH 4.0 to 10.3) implies that the PSF-F composite resin overcomes the limitations of the conventional ferrite process which is practically applicable only to alkaline conditions. The experiment proceeded using batch reactor in a constant temperature with water bath. The experiments divided into three parts. The first one is TG/DTA (Thermogravimetry / Differential Thermal Analysis) which can analyze the trend of pyrolysis of PSF-F ion exchanger. The Second one is equilibrium experiment in which the separation factor of metal ions and Langmuir, Freundlich isotherm was achieved. The last one is kinetics experiment in which the equilibrium reaction time and removal efficiency is estimated

  18. The difference between the metal ion extracted from the R.F. ion source by applying plasma chemistry reaction and by non-plasma range chemistry reaction

    International Nuclear Information System (INIS)

    Bai Gui Bin

    1987-01-01

    The paper introduced the difference between using plasma chemistry reaction draw metal ion and non-plasma range chemistry reaction in the R.F. ion source. By using of the plasma chemistry reaction draw metal ion higher percentage than non-plasma range chemistry reaction in the R.F. ion source. The authors plasma chemistry reaction to R.F. ion source and implanter successfully. The effect is very well, it has its own characteristic

  19. Water-soluble metal-binding polymers with ultrafiltration: A technology for the removal, concentration, and recovery of metal ions from aqueous streams

    International Nuclear Information System (INIS)

    Smith, B.F.; Robison, T.W.; Jarvinen, G.D.

    1997-01-01

    The use of water-soluble metal-binding polymers coupled with ultrafiltration (UF) is a technology under development to selectively concentrate and recover valuable or regulated metal-ions from dilute process or waste waters. The polymers have a sufficiently large molecular size that they can be separated and concentrated using commercially available UF technology. The polymers can then be reused by changing the solution conditions to release the metal-ions, which are recovered in a concentrated form for recycle or disposal. Pilot-scale demonstrations have been completed for a variety of waste streams containing low concentrations of metal ions including electroplating wastes (zinc and nickel) and nuclear waste streams (plutonium and americium). Many other potential commercial applications exist including remediation of contaminated solids. An overview of both the pilot-scale demonstrated applications and small scale testing of this technology are presented

  20. Water-soluble metal-binding polymers with ultrafiltration: A technology for the removal, concentration, and recovery of metal ions from aqueous streams

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.F.; Robison, T.W.; Jarvinen, G.D.

    1997-12-31

    The use of water-soluble metal-binding polymers coupled with ultrafiltration (UF) is a technology under development to selectively concentrate and recover valuable or regulated metal-ions from dilute process or waste waters. The polymers have a sufficiently large molecular size that they can be separated and concentrated using commercially available UF technology. The polymers can then be reused by changing the solution conditions to release the metal-ions, which are recovered in a concentrated form for recycle or disposal. Pilot-scale demonstrations have been completed for a variety of waste streams containing low concentrations of metal ions including electroplating wastes (zinc and nickel) and nuclear waste streams (plutonium and americium). Many other potential commercial applications exist including remediation of contaminated solids. An overview of both the pilot-scale demonstrated applications and small scale testing of this technology are presented.

  1. Effect of metal ions on the enzymatic hydrolysis of hemp seed oil by lipase Candida sp. 99-125.

    Science.gov (United States)

    Lu, Jike; Wang, Pei; Ke, Zhaodi; Liu, Xin; Kang, Qiaozhen; Hao, Limin

    2018-07-15

    In order to study the effect of metal ions on the enzymatic hydrolysis of hemp seed oil by Candida sp. 99-125, the spectroscopy, stability and hydrolytic activity of the biocatalyst were investigated in presence of Ca 2+ , Mg 2+ , Fe 2+ , Fe 3+ , Cu 2+ , Sn 2+ , Pb 2+ , Zn 2+ and Ba 2+ metal ions, respectively. The UV spectroscopy showed that all the metal ions enhanced the absorbance but the decrease of fluorescence intensity was observed. All the metal ions could improve the lipase thermal stability except Cu 2+ and Ba 2+ . Hydrolysis of hemp seed oil proved that Ca 2+ , Fe 3+ , Pb 2+ and Ba 2+ could significantly improve the hydrolytic rate, and metal ions could influence lipase selectivity. The study revealed that metal ions could improve lipase stability, hydrolysis activity in the hydrolytic process of hemp seed oil by Candida sp. 99-125. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Template-directed synthesis of oligoguanylic acids - Metal ion catalysis

    Science.gov (United States)

    Bridson, P. K.; Fakhrai, H.; Lohrmann, R.; Orgel, L. E.; Van Roode, M.

    1981-01-01

    The effects of Zn(2+), Pb(2+) and other metal ions on the efficiency and stereo-selectivity of the template-directed oligomerization of guanosine 5'-phosphorimidazolide are investigated. Reactions were run in the presence of a polyC template in a 2,6-lutidine buffer, and products analyzed by high-performance liquid chromatography on an RPC-5 column. The presence of the Pb(2+) ion is found to lead to the formation of 2'-5' linked oligomers up to the 40-mer, while Zn(2+) favors the formation of predominantly 3'-5' linked oligomers up to the 35-mer. When amounts of uracil, cytidine or adenosine 5'-phosphorimidazole equal to those of the guanosine derivative are included in the reaction mixture, the incorrect base is incorporated into the oligomer about 10% of the time with a Pb(2+) catalyst, but less than 0.5% of the time with Zn(2+). The Sn(2+), Sb(3+) and Bi(3+) ions are also found to promote the formation of 2'-5' oligomers, although not as effectively as Pb(2+), while no metal ions other than Zn(2+) promote the formation of the 3'-5' oligomers. The results may be important for the understanding of the evolution of nucleic acid replication in the absence of enzymes.

  3. Experimental demonstration of efficient and selective population transfer and qubit distillation in a rare-earth-metal-ion-doped crystal

    International Nuclear Information System (INIS)

    Rippe, Lars; Nilsson, Mattias; Kroell, Stefan; Klieber, Robert; Suter, Dieter

    2005-01-01

    In optically controlled quantum computers it may be favorable to address different qubits using light with different frequencies, since the optical diffraction does not then limit the distance between qubits. Using qubits that are close to each other enables qubit-qubit interactions and gate operations that are strong and fast in comparison to qubit-environment interactions and decoherence rates. However, as qubits are addressed in frequency space, great care has to be taken when designing the laser pulses, so that they perform the desired operation on one qubit, without affecting other qubits. Complex hyperbolic secant pulses have theoretically been shown to be excellent for such frequency-addressed quantum computing [I. Roos and K. Molmer, Phys. Rev. A 69, 022321 (2004)] - e.g., for use in quantum computers based on optical interactions in rare-earth-metal-ion-doped crystals. The optical transition lines of the rare-earth-metal-ions are inhomogeneously broadened and therefore the frequency of the excitation pulses can be used to selectively address qubit ions that are spatially separated by a distance much less than a wavelength. Here, frequency-selective transfer of qubit ions between qubit states using complex hyperbolic secant pulses is experimentally demonstrated. Transfer efficiencies better than 90% were obtained. Using the complex hyperbolic secant pulses it was also possible to create two groups of ions, absorbing at specific frequencies, where 85% of the ions at one of the frequencies was shifted out of resonance with the field when ions in the other frequency group were excited. This procedure of selecting interacting ions, called qubit distillation, was carried out in preparation for two-qubit gate operations in the rare-earth-metal-ion-doped crystals. The techniques for frequency-selective state-to-state transfer developed here may be also useful also for other quantum optics and quantum information experiments in these long-coherence-time solid

  4. Evaluation of a low-cost adsorbent for removal of toxic metal ions from wastewater of an electroplating factory.

    Science.gov (United States)

    Sousa, Francisco W; Sousa, Marcelo James; Oliveira, Isadora R N; Oliveira, André G; Cavalcante, Rivelino M; Fechine, Pierre B A; Neto, Vicente O S; de Keukeleire, Denis; Nascimento, Ronaldo F

    2009-08-01

    In this study, sugar cane residue or bagasse was used for removal of toxic metal ions from wastewater of an electroplating factory located in northeast Brazil. Prior acid treatment increased the adsorption efficacies in batch wise experiments. The microstructure of the material before and after the treatment was investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy. Column operations showed that removals of Cu(2+), Ni(2+) and Zn(2+) from wastewater (in the absence of cyanide) were 95.5%, 96.3.0%, and 97.1%, respectively. Regeneration of the adsorbent obtained in acid indicated that the efficiencies decreased only after the fourth cycle of re-use. Acid-treated sugar cane bagasse can be considered a viable alternative to common methods to remove toxic metal ions from aqueous effluents of electroplating industries.

  5. Sorption-spectroscopic and test methods for the determination of metal ions on the solid-phase of ion-exchange materials

    International Nuclear Information System (INIS)

    Savvin, Sergey B; Dedkova, Valentina P; Shvoeva, Ol'ga P

    2000-01-01

    Data on sorption-spectroscopic and test methods for the determination of metal ions on the solid-phase of ion-exchange materials published over the past decade are reviewed. The advantages and disadvantages of ion-exchange materials are discussed. The detection limits and selectivity of these techniques are described. The bibliography includes 151 references.

  6. Understanding interaction of curcumin and metal ions on electrode surfaces using EDXRF

    Science.gov (United States)

    Joseph, Daisy; Kumar, K. Krishna; Narayanan, S. Sriman

    2018-04-01

    A chemically modified electrode was developed for determination of metal ions (Cd, Pb, Zn, Co, Hg). The modifier used for the study was Curcumin. Curcumin acts as a complexing agent at the surface of the electrode for preconcentration of metal ions from electrolyte to electrode surface and stripped back to electrolyte during analysis. EDXRF was used to analyze these electrodes and it was concluded that the PCR modified electrode favored effective chelation for lead and mercury.

  7. Ion neutralization at metal surfaces by surface-plasmon excitation

    International Nuclear Information System (INIS)

    Almulhem, A.A.

    1988-01-01

    Electron capture by ions scattered from metal surfaces is usually assumed to occur via resonance tunneling or Auger neutralization. A new mechanism is proposed, wherein a surface plasmon is excited during the electron capture. The Fock-Tani transformation is used to transform the Hamiltonian into a form which explicitly contains a term that corresponds to this process. Using this term, the matrix elements are calculated analytically and used to evaluate the transition rate as a function of distance from the surface. Since this is a rearrangement process, the matrix element contains an orthogonalization term. The theory is applied to the scattering of protons from an aluminum surface in which the proton captures an electron into the 1s state. From the results obtained for the transition rate and neutral fractions, it is concluded that this process is important, at least in the low energy region. When the calculations are done with the orthogonalization term in the matrix element neglected, the transition rate and neutral fraction increased appreciably. This shows the importance of this term, and implies that it cannot be neglected as was done in other theories of neutralization at metal surfaces

  8. Influence of different metal ions on the ultrastructure, biochemical properties, and protein localization of the K562 cell nuclear matrix.

    Science.gov (United States)

    Neri, L M; Bortul, R; Zweyer, M; Tabellini, G; Borgatti, P; Marchisio, M; Bareggi, R; Capitani, S; Martelli, A M

    1999-06-01

    The higher order of chromatin organization is thought to be determined by the nuclear matrix, a mainly proteinaceous structure that would act as a nucleoskeleton. The matrix is obtained from isolated nuclei by a series of extraction steps involving the use of high salt and nonspecific nucleases, which remove chromatin and other loosely bound components. It is currently under debate whether these structures, isolated in vitro by unphysiological extraction buffers, correspond to a nucleoskeleton existing in vivo. In most cell types investigated, the nuclear matrix does not spontaneously resist these extractions steps; rather, it must be stabilized before the application of extracting agents. In this study nuclei, isolated from K562 human erythroleukemia cells, were stabilized by incubation with different metal ions (Ca2+, Cu2+, Zn2+, Cd2+), and the matrix was obtained by extraction with 2 M NaCl. By means of ultrastructural analysis of the resulting structures, we determined that, except for Ca2+, all the other metals induced a stabilization of the matrix, which retained the inner fibrogranular network and residual nucleoli. The biochemical composition, analyzed by two-dimensional gel electrophoresis separation, exhibited a distinct matrix polypeptide pattern, characteristic of each type of stabilizing ion employed. We also investigated to what extent metal ions could maintain in the final structures the original distribution of three inner matrix components, i.e. NuMA, topoisomerase IIalpha, and RNP. Confocal microscopy analysis showed that only NuMa, and, to a lesser extent, topoisomerase IIalpha, were unaffected by stabilization with divalent ions. On the contrary, the fluorescent RNP patterns detected in the resulting matrices were always disarranged, irrespective of the stabilization procedure. These results indicate that several metal ions are powerful stabilizing agents of the nuclear matrix prepared from K562 erythroleukemia cells and also strengthen the

  9. Chromatography of metal ions with a triazine chelating resin

    International Nuclear Information System (INIS)

    Wang, W.N.

    1979-05-01

    The synthesis, characterization, and some analytical applications of a new triazine resin are described. Separation of group IB, IIB, VIB, and VIIB metal ions from group VIII metal ions is achieved by this PDT-4 resin. Calcium(II) and magnesium(II) are taken up at pH = 6, 0.1 M acetate and are eluted at pH = 6, 0.1 M sodium nitrate. Copper(II) is retained at pH = 6, 0.1 M acetate and pH = 1 hydrochloric acid and is eluted subsequently by 5 M perchloric acid. Molybdenum(VI) is sorbed selectively from 0.1 N sulfuric acid or hydrochloric acid and is eluted in a tight band by 0.1 N sodium hydroxide. Numerous rapid column chromatographic separations are reported using this new resin, including analysis of NBS standard samples

  10. Colored cool colorants based on rare earth metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Sreeram, Kalarical Janardhanan; Aby, Cheruvathoor Poulose; Nair, Balachandran Unni; Ramasami, Thirumalachari [Chemical Laboratory, Central Leather Research Institute, Council of Scientific and Industrial Research, Adyar, Chennai 600 020 (India)

    2008-11-15

    Colored pigments with high near infrared reflectance and not based on toxic metal ions like cadmium, lead and cobalt are being sought as cool colorants. Through appropriate doping two pigments Ce-Pr-Mo and Ce-Pr-Fe have been developed to offer a reddish brown and reddish orange color, respectively. These pigments have been characterized and found to be highly crystalline with an average size of 300 nm. A shift in band gap energy from 2.21 to 2.18 eV has been observed when Li{sub 2}CO{sub 3} was used as a mineralizer. Scanning electron microscope-energy dispersive X-ray analysis (SEM-EDAX) measurement indicate a uniform grind shape and distribution of metal ion, with over 65% reflectance in the NIR region, these pigments can well serve as cool colorants. (author)

  11. Multistage leaching of metals from spent lithium ion battery waste using electrochemically generated acidic lixiviant.

    Science.gov (United States)

    Boxall, N J; Adamek, N; Cheng, K Y; Haque, N; Bruckard, W; Kaksonen, A H

    2018-04-01

    Lithium ion battery (LIB) waste contains significant valuable resources that could be recovered and reused to manufacture new products. This study aimed to develop an alternative process for extracting metals from LIB waste using acidic solutions generated by electrolysis for leaching. Results showed that solutions generated by electrolysis of 0.5 M NaCl at 8 V with graphite or mixed metal oxide (MMO) electrodes were weakly acidic and leach yields obtained under single stage (batch) leaching were poor (leaching with the graphite electrolyte solution improved leach yields overall, but the electrodes corroded over time. Though yields obtained with both electrolyte leach solutions were low when compared to the 4 M HCl control, there still remains potential to optimise the conditions for the generation of the acidic anolyte solution and the solubilisation of valuable metals from the LIB waste. A preliminary value proposition indicated that the process has the potential to be economically feasible if leach yields can be improved, especially based on the value of recoverable cobalt and lithium. Copyright © 2018 Elsevier Ltd. All rights reserved.

  12. Modification of metallic surfaces by positive ion bombardment

    International Nuclear Information System (INIS)

    Rickards C, J.

    1989-01-01

    Reported are the fundamentals and recent advances in the use of ion implantation techniques and gaseous emissions to modify metal surfaces. The physical phenomena involved, the necessary equipment and some applications which have been successful on an industrial scale are described. (Author). 13 refs, 1 fig

  13. Immobilization of transition metal ions on zirconium phosphate monolayers

    International Nuclear Information System (INIS)

    Melezhik, A.V.; Brej, V.V.

    1998-01-01

    It is shown that ions of transition metals (copper, iron, vanadyl, titanium) are adsorbed on zirconium phosphate monolayers. The zirconium phosphate threshold capacity corresponds to substitution of all protons of hydroxyphosphate groups by equivalent amounts of copper, iron or vanadyl. Adsorption of polynuclear ions is possible in case of titanium. The layered substance with specific surface up to 300 m 2 /g, wherein ultradispersed titanium dioxide particles are intercalirated between zirconium-phosphate layers, is synthesized

  14. Ion-beam modification of properties of metals and alloys

    International Nuclear Information System (INIS)

    Khodasevich, V.V.; Uglov, V.V.; Ponaryadov, V.V.; Zhukova, S.I.

    2002-01-01

    Physical fundaments for ion-beam modification and plasma-vacuum synthesis of new types of coatings and compounds in technically important metals and alloys were development as well as corresponding installation and technologies were created. (authors)

  15. Synthesis, photophysical and metal ion signalling behaviour of mono

    Indian Academy of Sciences (India)

    Unknown

    component systems, ... tion and heavy metal ions, is of considerable interest for various ... cause of the macrocyclic effect, expect to show ... whose chloride salt, mercuric chloride, was used. ... filtered, concentrated, washed with water and ex-.

  16. On the modification of metal/ceramic interfaces by low energy ion/atom bombardment during film growth

    International Nuclear Information System (INIS)

    Rigsbee, J.M.; Scott, P.A.; Knipe, R.K.; Hock, V.F.

    1986-01-01

    Elemental Cu and Ti films have been deposited onto ceramic substrates with a plasma-aided physical vapor deposition (ion-plating) process. This paper discusses how the structure and chemistry of the metallic film and the metal/ceramic interface are modified by low energy ion and neutral atom bombardment. Emphasis is placed on determining how low energy ion/neutral atom bombardment affects the strength of the metal/ceramic interface. Analyses of the film, interface and substrate regions have employed scanning Auger microprobe, secondary ion mass spectroscopy, SEM/STEM-energy dispersive X-ray and TEM/STEM imaging and microdiffraction techniques. (Auth.)

  17. 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.

  18. An Aqueous Metal-Ion Capacitor with Oxidized Carbon Nanotubes and Metallic Zinc Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Yuheng; Amal, Rose; Wang, Da-Wei, E-mail: da-wei.wang@unsw.edu.au [School of Chemical Engineering, The University of New South Wales (UNSW), Sydney, NSW (Australia)

    2016-10-03

    An aqueous metal ion capacitor comprising of a zinc anode, oxidized carbon nanotubes (oCNTs) cathode, and a zinc sulfate electrolyte is reported. Since the shuttling cation is Zn{sup 2+}, 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{sup −2} (corresponding to 53 F g{sup −1}) in the range of 0–1.8 V at 10 mV s{sup −1} and a stable cycling performance up to 5000 cycles.

  19. Surface metal standards produced by ion implantation through a removable layer

    International Nuclear Information System (INIS)

    Schueler, B.W.; Granger, C.N.; McCaig, L.; McKinley, J.M.; Metz, J.; Mowat, I.; Reich, D.F.; Smith, S.; Stevie, F.A.; Yang, M.H.

    2003-01-01

    Surface metal concentration standards were produced by ion implantation and investigated for their suitability to calibrate surface metal measurements by secondary ion mass spectrometry (SIMS). Single isotope implants were made through a 100 nm oxide layer on silicon. The implant energies were chosen to place the peak of the implanted species at a depth of 100 nm. Subsequent removal of the oxide layer was used to expose the implant peak and to produce controlled surface metal concentrations. Surface metal concentration measurements by time-of-flight SIMS (TOF-SIMS) with an analysis depth of 1 nm agreed with the expected surface concentrations of the implant standards with a relative mean standard deviation of 20%. Since the TOF-SIMS relative sensitivity factors (RSFs) were originally derived from surface metal measurements of surface contaminated silicon wafers, the agreement implies that the implant standards can be used to measure RSF values. The homogeneity of the surface metal concentration was typically <10%. The dopant dose remaining in silicon after oxide removal was measured using the surface-SIMS protocol. The measured implant dose agreed with the expected dose with a mean relative standard deviation of 25%

  20. A novel approach for predicting the uptake and toxicity of metallic and metalloid ions

    Science.gov (United States)

    Wang, Peng

    2011-01-01

    Electrostatic nature of plant plasma membrane (PM) plays significant roles in the ion uptake and toxicity. Electrical potential at the PM exterior surface (ψ0o) influences ion distribution at the PM exterior surface, and the depolarization of ψ0o negativity increases the electrical driving force for cation transport, but decreases the driving force for anion transport across the PMs. Assessing environmental risks of toxic ions has been a difficult task because the ion concentration (activity) in medium is not directly corrected to its potential effects. Medium characteristics like the content of major cations have important influences on the bioavailability and toxicity of ions in natural waters and soils. Models such as the Free Ion Activity Model (FIAM) and the Biotic Ligand Model (BLM), as usually employed, neglect the ψ0o and hence often lead to false conclusions about interaction mechanisms between toxic ions and major cations for biology. The neglect of ψ0o is not inconsistent with its importance, and possibly reflects the difficulty in the measurement of ψ0o. Based on the dual effects of the ψ0o, electrostatic models were developed to better predict the uptake and toxicity of metallic and metalloid ions. These results suggest that the electrostatic models provides a more robust mechanistic framework to assess metal(loid) ecotoxicity and predict critical metal(loid) concentrations linked to a biological effect, indicating its potential utility in risk assessment of metal(loid)s in water and terrestrial ecosystems. PMID:21386661

  1. Mechanism of selective ion flotation. 1. Selective flotation of transition metal cations

    International Nuclear Information System (INIS)

    Walkowiak, W.

    1991-01-01

    An experimental investigation is presented of the batch ion flotation of the transition metal cations Cr 3+ , Fe 3+ , Mn 2+ , Co 2+ , Zn 2+ , Ag + , Cd 2+ , and In 3+ from acidic aqueous solutions with sodium dodecylsulfonate and sodium dodecylbenzenesulfonate as anionic surfactants. The selectivity sequences Mn 2+ 2+ 2+ 3+ 3+ and Ag + 2+ 3+ are established, both from data for single and multi-ion metal cations solutions, where sublate was not formed in the bulk solution. Good agreement between the selectivity sequences and the values of ionic potential of metal cations was found. An experimental investigation was also performed on the solubility of sublates. The sublates solubility values are discussed in terms of ionic potentials of metal cations as well as of the surfactant size

  2. Production of Hydrated Metal Ions by Fast Ion or Atom Beam Sputtering. Collision-Induced Dissociation and Successive Hydration Energies of Gaseous Cu+ with 1-4 Water Molecules

    NARCIS (Netherlands)

    Magnera, Thomas F.; David, Donald E.; Stulik, Dusan; Orth, Robert G.; Jonkman, Harry T.; Michl, Josef

    1989-01-01

    Low-temperature sputtering of frozen aqueous solutions of metal salts, of hydrated crystalline transition-metal salts, of frosted metal surfaces, and of frosted metal salts with kiloelectronvolt energy rare gas atoms or ions produces copious amounts of cluster ions, among which M+(H2O)n and/or

  3. A theoretical model of a liquid metal ion source

    International Nuclear Information System (INIS)

    Kingham, D.R.; Swanson, L.W.

    1984-01-01

    A model of liquid metal ion source (LMIS) operation has been developed which gives a consistent picture of three different aspects of LMI sources: (i) the shape and size of the ion emitting region; (ii) the mechanism of ion formation; (iii) properties of the ion beam such as angular intensity and energy spread. It was found that the emitting region takes the shape of a jet-like protrusion on the end of a Taylor cone with ion emission from an area only a few tens of A across, in agreement with recent TEM pictures by Sudraud. This is consistent with ion formation predominantly by field evaporation. Calculated angular intensities and current-voltage characteristics based on our fluid dynamic jet-like protrusion model agree well with experiment. The formation of doubly charged ions is attributed to post-ionization of field evaporated singly charged ions and an apex field strength of about 2.0 V A -1 was calculated for a Ga source. The ion energy spread is mainly due to space charge effects, it is known to be reduced for doubly charged ions in agreement with this post-ionization mechanism. (author)

  4. Global transport and localized layering of metallic ions in the upper atmospherer

    Directory of Open Access Journals (Sweden)

    L. N. Carter

    Full Text Available A numerical model has been developed which is capable of simulating all phases of the life cycle of metallic ions, and results are described and interpreted herein for the typical case of Fe+ ions. This cycle begins with the initial deposition of metallics through meteor ablation and sputtering, followed by conversion of neutral Fe atoms to ions through photoionization and charge exchange with ambient ions. Global transport arising from daytime electric fields and poleward/ downward di.usion along geomagnetic field lines, localized transport and layer formation through de- scending convergent nulls in the thermospheric wind field, and finally annihilation by chemical neutralization and compound formation are treated. The model thus sheds new light on the interdependencies of the physical and chemical processes a.ecting atmospheric metallics. Model output analysis confirms the dominant role of both global and local transport to the ion's life cycle, showing that upward forcing from the equatorial electric field is critical to global movement, and that diurnal and semidiurnal tidal winds are responsible for the forma- tion of dense ion layers in the 90±250 km height region. It is demonstrated that the assumed combination of sources, chemical sinks, and transport mechanisms actually produces F-region densities and E-region layer densities similar to those observed. The model also shows that zonal and meridional winds and electric fields each play distinct roles in local transport, whereas the ion distribution is relatively insensitive to reasonable variations in meteoric deposition and chemical reaction rates.

    Key words. Ionosphere (ion chemistry and composition; ionosphere-atmosphere interactions.

  5. Predicting Metal Speciation & Bioavailability via Estimation of Metal-Organic Thermodynamic Properties

    Science.gov (United States)

    Prasad, A.; Howells, A. E.; Shock, E.

    2017-12-01

    The biological fate of any metal depends on its chemical form in the environment. Arsenic for example, is extremely toxic in the form of inorganic As+3 but completely benign in the organic form of arsenobetaine. Thus, given an exhaustive set of reactions and their equilibrium constants (logK), the bioavailability of any metal can be obtained for blood plasma, hydrothermal fluids or any system of interest. While many data exist for metal-inorganic ligands, logK data covering the temperature range of life for metal-organic complexes are sparse. Hence, we decided to estimate metal-organic logK values from correlations with the commonly available values of ligand pKa. Metal ion specific correlations were made with ligands classified according to their electron donor atoms, denticity and other chemical factors. While this approach has been employed before (Carbonaro et al. 2007, GCA 71, 3958-3968), new correlations were developed that provide estimates even when no metal-organic logK is available. In addition, we have used the same methods to make estimates of metal-organic entropy of association (ΔaS), which can provide logK for any temperature of biological relevance. Our current correlations employ logK and ΔaS data from 30 metal ions (like the biologically relevant Fe+3 & Zn+2) and 74 ligands (like formate and ethylenediamine), which can be expanded to estimate the metal-ligand reaction properties for these 30 metal ions with a possibly limitless number of ligands that may belong to our categories of ligands. With the help of such data, copper speciation was obtained for a defined growth medium for methanotrophs employed by Morton et al. (2000, AEM 66, 1730-1733) that agrees with experimental measurements showing that the free metal ion may not be the bioavailable form in all conditions. These results encourage us to keep filling the gaps in metal-organic logK data and continue finding relationships between biological responses (like metal-accumulation ratios

  6. Metal-Ion-Mediated Supramolecular Chirality of l-Phenylalanine Based Hydrogels.

    Science.gov (United States)

    Wang, Fang; Feng, Chuan-Liang

    2018-05-14

    For chiral hydrogels and related applications, one of the critical issues is how to control the chirality of supramolecular systems in an efficient way, including easy operation, efficient transfer of chirality, and so on. Herein, supramolecular chirality of l-phenylalanine based hydrogels can be effectively controlled by using a broad range of metal ions. The degree of twisting (twist pitch) and the diameter of the chiral nanostructures can also be efficiently regulated. These are ascribed to the synergic effect of hydrogen bonding and metal ion coordination. This study may develop a method to design a new class of electronically, optically, and biologically active materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Research of plasma-electrolyte discharge in the processes of obtaining metallic powders

    Science.gov (United States)

    Kashapov, R. N.; Kashapov, L. N.; Kashapov, N. F.

    2017-11-01

    The use of the plasma electrolyte process has never been considered as a simple, cheap and fast method of obtaining powders used in selective laser melting processes. Therefore, the adaptation of the plasma-electrolyte process to the production of metal powders used in additive production is an urgent task. The paper presents the results of studies of gas discharge parameters between a metal and liquid electrode in the processes of obtaining metallic iron powders. The discharge combustion conditions necessary for the formation of metal powders of micron size are determined. A possible mechanism for the formation of powder particles in a discharge plasma is proposed.

  8. Metal ion attachment to the matrix meso-tetrakis(pentafluorophenyl)porphyrin, related matrices and analytes: an experimental and theoretical study.

    Science.gov (United States)

    van Kampen, Jeroen J A; Luider, Theo M; Ruttink, Paul J A; Burgers, Peter C

    2009-11-01

    In a previous study [van Kampen et al. Analytical Chemistry 2006; 78: 5403], we found that meso-tetrakis (pentafluorophenyl)porphyrin (F20TPP), in combination with lithium salts, provides an efficient matrix to cationize small molecules by Li+ attachment and that this combination can be successfully applied to the quantitative analysis of drugs, such as antiretroviral compounds using matrix-assisted laser desorption ionization in conjunction with a time-of-flight analyzer (MALDI-TOF). In the present study, we further explore the mechanism of metal ion attachment to F20TPP and analytes by MALDI-FTMS(/MS). To this end, we have studied the interaction of F20TPP and analytes with various mono-, di- and trivalent metal ions (Li+, Na+, K+, Rb+, Cs+, Co2+, Cu2+, Zn2+, Fe2+, Fe3+ and Ga3+). For the alkali cations, we find that F20TPP forms complexes only with Li+ and Na+; in addition, model analyte molecules such as poly(ethyleneglycol)s, mixed with F20TPP and the alkali cations, also only form Li+ and Na+ adducts. This contrasts sharply with the commonly used matrix 2,5-dihydroxybenzoic acid, where analytes are most efficiently cationized by Na+ or K+. Reasons for this difference are delineated. Ab initio calculations on porphyrin itself reveal that even the smallest alkali cation, Li+, does not fit in the porphyrin cavity, but lies on top of it, pushing the 21H and 23 H hydrogen atoms out of and below the plane with concomitant bending of the porphyrin skeleton in the opposite direction, i.e. toward the cation. Thus, the Li+ ion is not effectively sequestered and is in fact exposed and thus accessible for donation to analyte molecules. Interaction of F20TPP with di- and trivalent metal ions leads to protoporphyrin-metal ions, where the metal ion is captured within the protoporphyrin dianion cavity. The most intense signal is obtained when F20TPP is reacted with CuCl2 and then subjected to laser ablation. This method presents an easy general route to study the metal

  9. Film sputtering with ion mixing in a pulse explosion-emission ion diode

    International Nuclear Information System (INIS)

    Korenev, S.A.; Balalykin, N.I.; Sikolenko, V.V.; Orelovich, O.L.; Shirokov, D.M.

    1995-01-01

    A possibility is confirmed of obtaining mixed composition films from mutually nonsoluble metals in conditions when a film is irradiated with an ion beam in the process of deposition and afterwards with an electron beam. In the experiments was used an explosion-emission ion diode. The experiments showed a possibility of obtaining a new structural material-aluminium with titanium film. 12 refs.; 7 figs.; 1 tab

  10. A Mononuclear Non-Heme Manganese(IV)-Oxo Complex Binding Redox-Inactive Metal Ions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Junying; Lee, Yong-Min; Davis, Katherine M.; Wu, Xiujuan; Seo, Mi Sook; Cho, Kyung-Bin; Yoon, Heejung; Park, Young Jun; Fukuzumi, Shunichi; Pushkar, Yulia N.; Nam, Wonwoo [Ewha; (Purdue); (Osaka)

    2013-05-29

    Redox-inactive metal ions play pivotal roles in regulating the reactivities of high-valent metal–oxo species in a variety of enzymatic and chemical reactions. A mononuclear non-heme Mn(IV)–oxo complex bearing a pentadentate N5 ligand has been synthesized and used in the synthesis of a Mn(IV)–oxo complex binding scandium ions. The Mn(IV)–oxo complexes were characterized with various spectroscopic methods. The reactivities of the Mn(IV)–oxo complex are markedly influenced by binding of Sc3+ ions in oxidation reactions, such as a ~2200-fold increase in the rate of oxidation of thioanisole (i.e., oxygen atom transfer) but a ~180-fold decrease in the rate of C–H bond activation of 1,4-cyclohexadiene (i.e., hydrogen atom transfer). The present results provide the first example of a non-heme Mn(IV)–oxo complex binding redox-inactive metal ions that shows a contrasting effect of the redox-inactive metal ions on the reactivities of metal–oxo species in the oxygen atom transfer and hydrogen atom transfer reactions.

  11. The effect of platform switching on the levels of metal ion release from different implant–abutment couples

    Science.gov (United States)

    Alrabeah, Ghada O; Knowles, Jonathan C; Petridis, Haralampos

    2016-01-01

    The improved peri-implant bone response demonstrated by platform switching may be the result of reduced amounts of metal ions released to the surrounding tissues. The aim of this study was to compare the levels of metal ions released from platform-matched and platform-switched implant–abutment couples as a result of accelerated corrosion. Thirty-six titanium alloy (Ti-6Al-4V) and cobalt–chrome alloy abutments were coupled with titanium cylinders forming either platform-switched or platform-matched groups (n=6). In addition, 18 unconnected samples served as controls. The specimens were subjected to accelerated corrosion by static immersion in 1% lactic acid for 1 week. The amount of metal ions ion of each test tube was measured using inductively coupled plasma mass spectrometry. Scanning electron microscope (SEM) images and energy dispersive spectroscopy X-ray analyses were performed pre- and post-immersion to assess corrosion at the interface. The platform-matched groups demonstrated higher ion release for vanadium, aluminium, cobalt, chrome, and molybdenum compared with the platform-switched groups (Pabutment size or connection (Pabutment platform surfaces. In conclusion, implant–abutment couples underwent an active corrosion process resulting in metal ions release into the surrounding environment. The highest amount of metal ions released was recorded for the platform-matched groups, suggesting that platform-switching concept has a positive effect in reducing the levels of metal ion release from the implant–abutment couples. PMID:27357323

  12. Recent Progress in Graphite Intercalation Compounds for Rechargeable Metal (Li, Na, K, Al)‐Ion Batteries

    Science.gov (United States)

    Xu, Jiantie; Dou, Yuhai; Wei, Zengxi; Li, Yutao; Liu, Huakun; Dou, Shixue

    2017-01-01

    Abstract Lithium‐ion batteries (LIBs) with higher energy density are very necessary to meet the increasing demand for devices with better performance. With the commercial success of lithiated graphite, other graphite intercalation compounds (GICs) have also been intensively reported, not only for LIBs, but also for other metal (Na, K, Al) ion batteries. In this Progress Report, we briefly review the application of GICs as anodes and cathodes in metal (Li, Na, K, Al) ion batteries. After a brief introduction on the development history of GICs, the electrochemistry of cationic GICs and anionic GICs is summarized. We further briefly summarize the use of cationic GICs and anionic GICs in alkali ion batteries and the use of anionic GICs in aluminium‐ion batteries. Finally, we reach some conclusions on the drawbacks, major progress, emerging challenges, and some perspectives on the development of GICs for metal (Li, Na, K, Al) ion batteries. Further development of GICs for metal (Li, Na, K, Al) ion batteries is not only a strong supplement to the commercialized success of lithiated‐graphite for LIBs, but also an effective strategy to develop diverse high‐energy batteries for stationary energy storage in the future. PMID:29051856

  13. Ion bombardment induced smoothing of amorphous metallic surfaces: Experiments versus computer simulations

    International Nuclear Information System (INIS)

    Vauth, Sebastian; Mayr, S. G.

    2008-01-01

    Smoothing of rough amorphous metallic surfaces by bombardment with heavy ions in the low keV regime is investigated by a combined experimental-simulational study. Vapor deposited rough amorphous Zr 65 Al 7.5 Cu 27.5 films are the basis for systematic in situ scanning tunneling microscopy measurements on the smoothing reaction due to 3 keV Kr + ion bombardment. The experimental results are directly compared to the predictions of a multiscale simulation approach, which incorporates stochastic rate equations of the Langevin type in combination with previously reported classical molecular dynamics simulations [Phys. Rev. B 75, 224107 (2007)] to model surface smoothing across length and time scales. The combined approach of experiments and simulations clearly corroborates a key role of ion induced viscous flow and ballistic effects in low keV heavy ion induced smoothing of amorphous metallic surfaces at ambient temperatures

  14. FTIR spectroscopy structural analysis of the interaction between Lactobacillus kefir S-layers and metal ions

    Science.gov (United States)

    Gerbino, E.; Mobili, P.; Tymczyszyn, E.; Fausto, R.; Gómez-Zavaglia, A.

    2011-02-01

    FTIR spectroscopy was used to structurally characterize the interaction of S-layer proteins extracted from two strains of Lactobacillus kefir (the aggregating CIDCA 8348 and the non-aggregating JCM 5818) with metal ions (Cd +2, Zn +2, Pb +2 and Ni +2). The infrared spectra indicate that the metal/protein interaction occurs mainly through the carboxylate groups of the side chains of Asp and Glut residues, with some contribution of the NH groups belonging to the peptide backbone. The frequency separation between the νCOO - anti-symmetric and symmetric stretching vibrations in the spectra of the S-layers in presence of the metal ions was found to be ca. 190 cm -1 for S-layer CIDCA 8348 and ca. 170 cm -1 for JCM 5818, denoting an unidentate coordination in both cases. Changes in the secondary structures of the S-layers induced by the interaction with the metal ions were also noticed: a general trend to increase the amount of β-sheet structures and to reduce the amount of α-helices was observed. These changes allow the proteins to adjust their structure to the presence of the metal ions at minimum energy expense, and accordingly, these adjustments were found to be more important for the bigger ions.

  15. The deposition of thin metal films at the high-intensity pulsed-ion-beam influence on the metals

    International Nuclear Information System (INIS)

    Remnev, G.E.; Zakoutaev, A.N.; Grushin, I.I.; Matvenko, V.M.; Potemkin, A.V.; Ryzhkov, V.A.; Chernikov, E.V.

    1996-01-01

    A high-intensity pulsed ion beam with parameters: ion energy 350-500 keV, ion current density at a target > 200 A/cm 2 , pulse duration 60 ns, was used for metal deposition. The film deposition rate was 0.6-4.0 mm/s. Transmission electron microscopy/transmission electron diffraction investigations of the copper target-film system were performed. The impurity content in the film was determined by x-ray fluorescence analysis and secondary ion mass spectrometry. The angular distributions of the ablated plasma were measured. (author). 2 figs., 7 refs

  16. The deposition of thin metal films at the high-intensity pulsed-ion-beam influence on the metals

    Energy Technology Data Exchange (ETDEWEB)

    Remnev, G E; Zakoutaev, A N; Grushin, I I; Matvenko, V M; Potemkin, A V; Ryzhkov, V A [Tomsk Polytechnic Univ. (Russian Federation). Nuclear Physics Inst.; Ivanov, Yu F [Construction Academy, Tomsk (Russian Federation); Chernikov, E V [Siberian Physical Technical Institute, Tomsk (Russian Federation)

    1997-12-31

    A high-intensity pulsed ion beam with parameters: ion energy 350-500 keV, ion current density at a target > 200 A/cm{sup 2}, pulse duration 60 ns, was used for metal deposition. The film deposition rate was 0.6-4.0 mm/s. Transmission electron microscopy/transmission electron diffraction investigations of the copper target-film system were performed. The impurity content in the film was determined by x-ray fluorescence analysis and secondary ion mass spectrometry. The angular distributions of the ablated plasma were measured. (author). 2 figs., 7 refs.

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

    International Nuclear Information System (INIS)

    Sato, Sanae; Yoshihara, Kazuya; Moriyama, Koji; Machida, Motoi; Tatsumoto, Hideki

    2007-01-01

    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 Cπ-cation interaction for the heavy metals adsorption, and from some kind of oxygen-aromatics interaction to π-π dispersion for the aromatics

  18. Method and electrochemical cell for synthesis and treatment of metal monolayer electrocatalysts metal, carbon, and oxide nanoparticles ion batch, or in continuous fashion

    Science.gov (United States)

    Adzic, Radoslav; Zhang, Junliang; Sasaki, Kotaro

    2015-04-28

    An apparatus and method for synthesis and treatment of electrocatalyst particles in batch or continuous fashion is provided. In one embodiment, the apparatus comprises a sonication bath and a two-compartment chamber submerged in the sonication bath. The upper and lower compartments are separated by a microporous material surface. The upper compartment comprises a cover and a working electrode (WE) connected to a Pt foil contact, with the foil contact connected to the microporous material. The upper chamber further comprises reference counter electrodes. The lower compartment comprises an electrochemical cell containing a solution of metal ions. In one embodiment, the method for synthesis of electrocatalysts comprises introducing a plurality of particles into the apparatus and applying sonication and an electrical potential to the microporous material connected to the WE. After the non-noble metal ions are deposited onto the particles, the non-noble metal ions are displaced by noble-metal ions by galvanic displacement.

  19. Removing roughness on metal surface by irradiation of intense short-pulsed ion beams

    International Nuclear Information System (INIS)

    Hashimoto, Y.

    1995-01-01

    Surface modification of metals with an intense pulsed ion beam (IPIB) was studied experimentally. When the temperature rise of metal surfaces by IPIB irradiation exceeds their boiling point, it is found that machining roughness on surfaces is removed. The experiments were performed with the pulsed power generator HARIMA-II at Himeji Institute of Technology. The main components of the ion beam were carbon and fluorine ions. The IPIB was irradiated to metal plates (Al, Cu and Ti) which were placed at the focal point. Machining roughness on Ti surface was removed after IPIB irradiation, while roughness on Al and Cu plates was not removed. Using the present experimental parameters (beam power density: 32 W/cm 2 , pulse width: 25 ns), the temperature rise of the Ti surface was estimated to be 8,100 K which exceed its boiling point (3,000 K). However, the estimated temperatures of Al and Cu surfaces was 2,500 and 1,500 K, respectively, that are less than their boiling points. These studies above suggests that temperature rise over the boiling point of metals is necessary for removing machining roughness on metal surfaces

  20. Ion beam exposure apparatus using a liquid metal source

    International Nuclear Information System (INIS)

    Komuro, M.

    1982-01-01

    A field effect liquid metal ion source is described. The current-voltage characteristics, the angular intensity distribution and the total energy distribution were measured for gallium, gold and lead sources. The results are presented and the effect of space charge on the emission current is discussed. Optimum working conditions for the use of the ion sources in probe formation are derived. On the basis of the experimental results, an apparatus operating at 50 kV or less was designed. Details of the design, which includes a triode ion gun and an einzel lens, are given together with preliminary results of pattern delineation with the apparatus. (Auth.)

  1. Versatile nature of hetero-chitosan based derivatives as biodegradable adsorbent for heavy metal ions; a review.

    Science.gov (United States)

    Ahmad, Mudasir; Manzoor, Kaiser; Ikram, Saiqa

    2017-12-01

    The polyfunctional chitosan can act as the biological macromolecule ligand not only for the adsorption and the recovery of metal ions from an aqueous media, but also for the fabrication of novel adsorbents which shows selectivity and better adsorption properties. The unmodified chitosan itself, a single cationic polysaccharide, has hydroxyl and amine groups carrying complex properties with the metal ions. In addition, the selectivity of metal ions, the adsorption efficiency and adsorption capacity of the adsorbent can be modified chemically. This review covers the synthetic strategies of chitosan towards the synthesis of hetero-chitosan based adsorbents via chemical modifications in past two decades. It also includes how chemical modification influences the metal adsorption with N, O, S and P containing chitosan derivatives. Hope this review article provides an opportunity for researchers in the future to explore the potential of chitosan as an adsorbent for removal of metal ions from wastewater. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Removal of some heavy metals from industrial waste water using polyacrylamide ferric antimonate as new ion exchange material

    International Nuclear Information System (INIS)

    El-Aryan, Y.F.A.

    2011-01-01

    Composite ion exchangers consist of one or more ion exchangers combined with another material, which can be inorganic or organic and may it be an ion exchanger. The reason for manufacturing a composite material is to produce a granular material, with sufficient strength for column use, from ion exchangers that do not form, or only form weak, granules themselves. Attempts in this study are focused to prepare composite ion exchangers for treatment of wastewater. Heavy metals when present in water in concentrations exceeding the permitted limits are injurious to the health. Hence, it is very important to treat such waters to remove the metal ions present before it is supplied for any useful purpose. Therefore, many investigations have studied to develop more effective process to treat such waste stream. Ion-exchange has been widely adopted in heavy metal containing wastewater and most of the ion-exchangers (i.e. ion-exchange media) currently being used are commercially mass-produced organic resins.Therefore, the main aim of this work is directed to find the optimum conditions for removal of some heavy metals from industrial waste water.1-Preparation of polyacrylamide ferric antimonate composite.2-Characterization of the prepared exchanger using IR spectra, X-ray diffraction pattern, DTA and TG analyses.3-Chemical stability, capacity and equilibrium measurements will be determined on the materials using at different conditions (ph heating temperature and reaction temperature).4-Kinetic studies of some heavy metals.5-Ion exchange isotherm.6-Breakthrough curves for removal of the investigated metal ions on the prepared exchanger under certain condition.

  3. Interaction of Cr (III), Ni (II), Pb (II) with DTPA complexes of essential metal ions

    International Nuclear Information System (INIS)

    Gulzar, S.; Zahida; Maqsood, T.; Naqvi, R.R.

    2002-01-01

    With the increase of anthropogenic activities in the environment, heavy metal toxicity (Chromium, Nickel and Lead) is more common now. DTPA (diethylene triamine pentaacetic acid) a polyamino carboxylic acid is widely used to form hydrophilic and stable complexes with most of the metal ions. In this spectrophotometric study, concentration of Cr(III), Ni(II) and Pb(II) (toxic metal ions) exchanged with Fe(III), Zn(II) and Ca(II) from their DTPA complexes were estimated at pH 4,7 and 9. Concentration of added metal was varied from 1-4 times to that of complexed metal. (author)

  4. Conversion of agonist site to metal-ion chelator site in the beta(2)-adrenergic receptor

    DEFF Research Database (Denmark)

    Elling, C E; Thirstrup, K; Holst, Birgitte

    1999-01-01

    Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the beta(2)-adrenergic receptor,...... as generic, pharmacologic tools to switch 7TM receptors with engineered metal-ion sites on or off at will.......Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the beta(2)-adrenergic receptor......, in this paper we construct an activating metal-ion site between the amine-binding Asp-113 in TM-III-or a His residue introduced at this position-and a Cys residue substituted for Asn-312 in TM-VII. No increase in constitutive activity was observed in the mutant receptors. Signal transduction was activated...

  5. Oxidation of sulfur (IV by oxygen in aqueous solution: role of some metal ions

    Directory of Open Access Journals (Sweden)

    Martins Claudia R.

    1999-01-01

    Full Text Available Catalytic effect of metal ions: Cr(VI, Cr(III, Cd(II, V(V and chloride anion, on the oxidation of S(IV in aqueous solution, at concentrations of metal ions and S(IV usually found in urban atmospheres, were studied under controlled experimental conditions (pH (2.1 - 4,5, T (25.0 - 35.0 °C, air flow rate, concentration of reactants, etc.... The kinetic constant determined at 25.0 °C and pH range (2.1 - 4.5, using ultra pure water was 8.0 ± 0.5 x 10-4 s-1. This value was considered as a reference for the oxidation reaction rate. The kinetic constants determined in the presence of Cr(VI revealed that the oxidation reaction of S(IV is quite influenced by the acidity. At pH = 2.1 (K = 2.3 x 10-2 mg-1 L s-1 the reaction is carried out with a rate five times greater when compared to pH = 2.6 (K = 4.3 x 10-3 mg-1 L s-1 and thirty times greater when compared to pH = 3.4 (K= 8.0 x 10 -4 mg-1 L s-1. The following rate expression was obtained at pH = 2.6: -r(S(IV =K [Cr(VI] [S(IV] and the activation energy found was: Ea =70.3KJ/mol. No catalytic effects were observed for Cd(II or chloride ion, while inhibitory effects were observed for Cr(III and V(V ions.

  6. High energy metal ion implantation using 'Magis', a novel, broad-beam, Marx-generator-based ion source

    International Nuclear Information System (INIS)

    Anders, A.; Brown, I.G.; Dickinson, M.R.; MacGill, R.A.

    1996-08-01

    Ion energy of the beam formed by an ion source is proportional to extractor voltage and ion charge state. Increasing the voltage is difficult and costly for extraction voltage over 100 kV. Here we explore the possibility of increasing the charge states of metal ions to facilitate high-energy, broad beam ion implantation at a moderate voltage level. Strategies to enhance the ion charge state include operating in the regimes of high-current vacuum sparks and short pulses. Using a time-of-flight technique we have measured charge states as high as 7+ (73 kA vacuum spark discharge) and 4+ (14 kA short pulse arc discharge), both for copper, with the mean ion charge states about 6.0 and 2.5, respectively. Pulsed discharges can conveniently be driven by a modified Marx generator, allowing operation of ''Magis'' with a single power supply (at ground potential) for both plasma production and ion extraction

  7. No Giant Two-Ion Anisotropy in the Heavy-Rare-Earth Metals

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    1976-01-01

    A new Bose-operator expansion of tensor operators is applied to the heavy-rare-earth metals. The Er data for the cone phase have been analyzed successfully with single-ion anisotropy and isotropic exchange interaction. The Tb data can be understood on the same basis. The previously found large two......-ion anisotropy was due to an inadequate treatment of the large single-ion anisotropy leading to an incorrect expression for the spin-wave energy....

  8. Angular and mass resolved energy distribution measurements with a gallium liquid metal ion source

    International Nuclear Information System (INIS)

    Marriott, Philip

    1987-06-01

    Ionisation and energy broadening mechanisms relevant to liquid metal ion sources are discussed. A review of experimental results giving a picture of source operation and a discussion of the emission mechanisms thought to occur for the ionic species and droplets emitted is presented. Further work is suggested by this review and an analysis system for angular and mass resolved energy distribution measurements of liquid metal ion source beams has been constructed. The energy analyser has been calibrated and a series of measurements, both on and off the beam axis, of 69 Ga + , Ga ++ and Ga 2 + ions emitted at various currents from a gallium source has been performed. A comparison is made between these results and published work where possible, and the results are discussed with the aim of determining the emission and energy spread mechanisms operating in the gallium liquid metal ion source. (author)

  9. Silica coated magnetite nanoparticles for removal of heavy metal ions from polluted waters

    CERN Document Server

    Dash, Monika

    2013-01-01

    Magnetic removal of Hg2+ and other heavy metal ions like Cd2+, Pb2+ etc. using silica coated magnetite particles from polluted waters is a current topic of active research to provide efficient water recycling and long term high quality water. The technique used to study the bonding characteristics of such kind of nanoparticles with the heavy metal ions is a very sensitive hyperfine specroscopy technique called the perturbed angular correlation technique (PAC).

  10. Characterization of copper thin films prepared by metal self-ion beam sputter deposition

    International Nuclear Information System (INIS)

    Gotoh, Yasuhito; Amioka, Takao; Tsuji, Hiroshi; Ishikawa, Junzo

    1994-01-01

    New deposition technique, 'metal-ion beam self-sputtering' method has been developed. Using metal ions which is the same element with the target material, no contamination with noble gas atoms, which are often used in the conventional sputtering, will occur. In this paper, fundamental measurement of the film purity is reported. As a result of PIXE measurements, it was clarified that only slight amount of iron is incorporated in the films. (author)

  11. Comprehensive evaluation on effective leaching of critical metals from spent lithium-ion batteries.

    Science.gov (United States)

    Gao, Wenfang; Liu, Chenming; Cao, Hongbin; Zheng, Xiaohong; Lin, Xiao; Wang, Haijuan; Zhang, Yi; Sun, Zhi

    2018-05-01

    Recovery of metals from spent lithium-ion batteries (LIBs) has attracted worldwide attention because of issues from both environmental impacts and resource supply. Leaching, for instance using an acidic solution, is a critical step for effective recovery of metals from spent LIBs. To achieve both high leaching efficiency and selectivity of the targeted metals, improved understanding on the interactive features of the materials and leaching solutions is highly required. However, such understanding is still limited at least caused by the variation on physiochemical properties of different leaching solutions. In this research, a comprehensive investigation and evaluation on the leaching process using acidic solutions to recycle spent LIBs is carried out. Through analyzing two important parameters, i.e. leaching speed and recovery rate of the corresponding metals, the effects of hydrogen ion concentration, acid species and concentration on these two parameters were evaluated. It was found that a leachant with organic acids may leach Co and Li from the cathode scrap and leave Al foil as metallic form with high leaching selectivity, while that with inorganic acids typically leach all metals into the solution. Inconsistency between the leaching selectivity and efficiency during spent LIBs recycling is frequently noticed. In order to achieve an optimal status with both high leaching selectivity and efficiency (especially at high solid-to-liquid ratios), it is important to manipulate the average leaching speed and recovery rate of metals to optimize the leaching conditions. Subsequently, it is found that the leaching speed is significantly dependent on the hydrogen ion concentration and the capability of releasing hydrogen ions of the acidic leachant during leaching. With this research, it is expected to improve understanding on controlling the physiochemical properties of a leaching solution and to potentially design processes for spent LIBs recycling with high industrial

  12. On the possibility of removing of transition metal ions from sewage using polymeric complexes

    International Nuclear Information System (INIS)

    Tazhibaeva, S.M.; Abilov, Zh.A.; Musabekov, K.V.

    1997-01-01

    The possibility of using of complexation in the system polyethylene-imine transition metal ions (Cu 2+ , Ni 2+ , Co 2+ )-surface active substance for removing of metal ions from solution and sewage has been investigated. It is shown, that pH of medium, hydro-fugitive of system and ratio between component of the triply complex effect on purification of solution. (author)

  13. Facile preparation of highly hydrophilic, recyclable high-performance polyimide adsorbents for the removal of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Jieyang; Zheng, Yaxin; Luo, Longbo; Feng, Yan [State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Zhang, Chaoliang [State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu 610041 (China); Wang, Xu, E-mail: wx19861027@163.com [State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Liu, Xiangyang, E-mail: lxy6912@sina.com [State Key Laboratory of Polymer Material and Engineering, College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China)

    2016-04-05

    Highlights: • High-performance polyimide was used as heavy metal adsorbents. • The contradiction between hydrophilicity and high performance of PI was solved. • Adsorption amount for Cu{sup 2+} of PI/silica was 77 times higher than that of PI. • The adsorption ability remained steady for more than 50 recycling processes. - Abstract: To obtain high-performance adsorbents that combine excellent adsorption ability, thermal stability, service life and recycling ability, polyimide (PI)/silica powders were prepared via a facile one-pot coprecipitation process. A benzimidazole unit was introduced into the PI backbone as the adsorption site. The benzimidazole unit induced more hydroxyls onto the silica, which provided hydrophilic sites for access by heavy metal ions. By comprehensively analyzing the effect of hydrophilcity, agglomeration, silica polycondensation, specific surface area and PI crystallinity, 10% was demonstrated to be the most proper feed silica content. The equilibrium adsorption amount (Q{sub e}) for Cu{sup 2+} of PI/silica adsorbents was 77 times higher than that of pure PI. Hydrogen chloride (HCl) was used as a desorbent for heavy metal ions and could be decomplexed with benzimidazole unit at around 300 °C, which was lower than the glass transition temperature of PI. The complexation and decomplexation process of HCl made PI/silica adsorbents recyclable, and the adsorption ability remained steady for more than 50 recycling processes. As PI/silica adsorbents possess excellent thermal stability, chemical resistance and radiation resistance and hydrophilicity, they have potential as superior recyclable adsorbents for collecting heavy metal ions from waste water in extreme environments.

  14. Photoassisted reduction of metal ions and organic dye by titanium dioxide nanoparticles in aqueous solution under anoxic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Doong, Ruey-An, E-mail: radoong@mx.nthu.edu.tw [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu, 30013, Taiwan (China); Hsieh, Tien-Chin [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 101, Sec. 2, Kuang Fu Road, Hsinchu, 30013, Taiwan (China); Huang, Chin-Pao [Department of Civil and Environmental Engineering, University of Delaware, Newark, 19716, Delaware (United States)

    2010-07-15

    The photoassisted reduction of metal ions and organic dye by metal-deposited Degussa P25 TiO{sub 2} nanoparticles was investigated. Copper and silver ions were selected as the target metal ions to modify the surface properties of TiO{sub 2} and to enhance the photocatalytic activity of TiO{sub 2} towards methylene blue (MB) degradation. X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) were used to characterize the crystallinity, chemical species and morphology of metal-deposited TiO{sub 2}, respectively. Results showed that the particle size of metal-deposited TiO{sub 2} was larger than that of Degussa P25 TiO{sub 2}. Based on XRPD patterns and XPS spectra, it was observed that the addition of formate promoted the photoreduction of metal ion by lowering its oxidation number, and subsequently enhancing the photodegradation efficiency and rate of MB. The pseudo-first-order rate constant (k{sub obs}) for MB photodegradation by Degussa P25 TiO{sub 2} was 3.94 x 10{sup -2} min{sup -1} and increased by 1.4-1.7 times in k{sub obs} with metal-deposited TiO{sub 2} for MB photodegradation compared to simple Degussa P25 TiO{sub 2}. The increase in mass loading of metal ions significantly enhanced the photodegradation efficiency of MB; the k{sub obs} for MB degradation increased from 3.94 x 10{sup -2} min{sup -1} in the absence of metal ion to 4.64-7.28 x 10{sup -2} min{sup -1} for Ag/TiO{sub 2} and to 5.14-7.61 x 10{sup -2} min{sup -1} for Cu/TiO{sub 2}. In addition, the electrons generated from TiO{sub 2} can effectively reduce metal ions and MB simultaneously under anoxic conditions. However, metal ions and organic dye would compete for electrons from the illuminated TiO{sub 2}.

  15. Adsorption of heavy metals ions on portulaca oleracea plants

    International Nuclear Information System (INIS)

    Naqvi, R.R.

    2005-01-01

    The aim of this study is to report the ability of portulaca oleracea (Fershi in Urdu) biomass grown in uncontaminated soils to adsorb or uptake lead, cadmium, arsenic, cobalt and copper from aqueous solutions. In order to help understand the metal binding mechanism, laboratory experiments performance to determine optimal binding, and binding capacity for each of the above mentioned metals. These experiments were carried out for the mass of crushed portulaca stems. Portulaca is a plant that grows abundantly in temperature climate in the area of Quetta Balochistan. It has reddish stem and thick succulent leaves. This plant has been found to be good adsorbent for heavy metals ions. (author)

  16. PIGMENT CONTENT OF Chlorella vulgaris BEIJ. UNDER INFLUENCE OF THE SODIUM SELENITE AND METALS IONS

    Directory of Open Access Journals (Sweden)

    O. I.

    2016-02-01

    Full Text Available The aim of the research was to determine the conditions obtaining in the aquaculture of Chlorella vulgaris Beij. algosubstantion enriched with selenium and bioactive metals. For this purpose, the content of seaweed pigments studied by the action of sodium selenite in a concentration based on Se4+: 0.5, 5.0, 10.0 and 20.0 mg / dm3 for 1, 3 and 7 days and while exposed 10.0 mg Se4 +/dm3 and Zn2+, Mn2 +, Co2 +, Cu2 +, Fe3 + in concentrations of 5.0 mg/dm 3, 0.25, 0.002, 0.008 and 0.05 mg/dm3, respectively, within 7 days of culturing. The content of pigments was determined spectrophotometrically, the cellular walls were given off in the percoll gradient and investigated microscopically. The pigments content in Ch. vulgaris increase by 1,5–2,5 times in comparison with control sample under the influence of 10 mg Se(IV/dm3 with and without metal ions. In the same condition a ratio of chlorophylls a/b increased, that accompanied by the formation in cells of the second cell wall as the sign of successful adaptation process in the Chlorella cells under the influence of these factors. Thus, the cultivation of chlorella, enriched with selenium and bioactive metals, is possible within 7 days under the influence of 10 mg Se (IV/dm3 and mentioned concentration of these metal ions.

  17. Electrochemical and corrosion behaviour of ion and laser-beam modified metal surfaces

    International Nuclear Information System (INIS)

    Bonora, P.L.

    1989-01-01

    Ion implantation may improve the resistance of metals to wear and corrosion both: by the formation of stable or metastable chemical compounds localized in a thin external layer; or by the so-called 'radiation damage' which is mainly active in lowering the potential gradients between different grains and between grain and grain boundaries as an effect of subdivision into substructures, up to a quasi-amorphous inert surface. The changes in the corrosion fatigue behaviour of iron as well as in its catalytic properties as a consequence of ion implantation are considered. The electrochemical behaviour of laser irradiated and ion mixed metals in terms of changed corrosion rate, corrosion morphology, passivability or breakdown of passivity is also explained. 27 refs.; 12 figs.; 5 tabs

  18. Effects of site substitution and metal ion addition on doped manganites

    CERN Document Server

    Pradhan, A K; Roul, B K; Sahu, D R; Muralidhar, M

    2002-01-01

    We report transport, magnetization and transmission electron microscopy studies of the effects of A-and B-site substitution, and the addition of metal ions such as Pt, Ag and Sr, on doped ABO sub 3 perovskites, where A = La, Pr etc and B = Mn. Disorder induced by such substitution changes the behaviour of the charge-ordered (CO) state significantly. A-and B-site substitution suppresses the CO phase due to size mismatch and disorder produced by inhomogeneity. On the other hand, addition of metal ions such as Pt and Ag improves several colossal-magnetoresistance properties significantly due to microstructural effects and enhanced current percolation through grain boundaries.

  19. Investigation of the depth profile of ion beam induced nanopatterns on Si with simultaneous metal incorporation

    Energy Technology Data Exchange (ETDEWEB)

    Khanbabaee, Behnam; Arezki, Bahia; Biermanns, Andreas; Pietsch, Ullrich [Festkoerperphysik, Universitaet Siegen, Siegen (Germany); Cornejo, Marina; Frost, Frank [Leibniz-Institut fuer Oberflaechenmodifizierung (IOM), Leipzig (Germany)

    2011-07-01

    Ion beam sputtering of semiconductor surfaces can modify the surface and produce a diversity of surface topographies such as periodic ripples or dot structures depended on sputtering parameters. Well ordered nanostructured surfaces have widely technological applications. Recent experiments have shown that the incorporation of metallic impurity atoms during the sputtering process plays a crucial role in pattern formation on the surfaces. These findings offer a new degree of freedom to control pattern formation. In this contribution we report on surface patterning due to Kr ion beam erosion on silicon surfaces with simultaneous Fe and Cr incorporation. We used X-ray reflectivity (XRR) to determine the depth profiles of metal ions as function of ion beam divergence angles and the mean incidence angle of the ions with respect to the surface normal. Depth profiles are correlated with degree of pattern formation determined by AFM. We show that the mean penetration depth and concentration of metal ions depends on the divergence angle of Kr beam provided by Kaufman source which supports the assumption that metal ions are created due to parasitic interaction of the Kr beam with the steel plate lining. The evaluated depth profile by XRR is in good agreement with SIMS and RBS results.

  20. Combined transmission electron microscope and ion channeling study of metastable metal alloys formed by ion implantation

    International Nuclear Information System (INIS)

    Cullis, A.G.; Borders, J.A.; Hirvonen, J.K.; Poate, J.M.

    1977-01-01

    Recently, ion implantation has been used to produce metastable alloy layers with a range of structures from crystalline substitutional solid solutions to amorphous. The technique offers the possibility of producing metastable metal layers with unique physical properties. Its application in the formation of alloys exhibiting different although complementary types of metastability is described. The metal combinations chosen (Ag-Cu and Ta-Cu) show little mutual solubility under equilibrium conditions

  1. Investigation of heavy metal removal from motorway stormwater using inorganic ion exchange

    International Nuclear Information System (INIS)

    Pitcher, Sarah

    2002-01-01

    Stormwater runoff from motorway surfaces contains toxic heavy metals that are not sufficiently removed by current treatment systems. This research has investigated the potential use of inorganic ion exchange materials to further reduce the levels of dissolved heavy metals. Candidate materials (synthetic/natural zeolites, clay/modified clay, hydrotalcite, lignite) were tested by a shaking procedure (mixed 5 mg dm -3 of each heavy metals, shaken for 10 min) and analysed by atomic absorption spectrometry. The synthetic zeolites MAP and Y showed 100% heavy metal removal and were investigated further by a series of batch experiments. The zeolites exhibited a selectivity sequence Pb > Cu > Cd ∼ Zn. Zeolite MAP has a high capacity for heavy metal uptake (4.5 meq g -1 ), but is not practical for use in a treatment facility owing to its low particle size (3 μm). However, large zeolite pellets (∼ 2 mm) were found to have a low heavy metal uptake (∼ 44 %) due to diffusion limitations. Selected materials (zeolites MAP, Y, mordenite, and carbon-based lignite) were tested in actual and spiked motorway stormwater. The synthetic zeolites effectively remove heavy metals (∼ 100 %) but change the environmental chemistry of the stormwater by releasing high concentrations of sodium, removing calcium ions and increasing the solution pH. The presence of other dissolved contaminants in motorway stormwater inhibited the uptake of heavy metals by the natural zeolite mordenite (34 % less removal). Alkali/alkaline-earth metals (Na, Ca) in solution compete for exchange sites in lignite and mordenite, reducing the heavy metal uptake. Chloride in solution forms complexes with cadmium, severely reducing its uptake by zeolite Y. The presence of dissolved road salt is a potentially serious concern as it causes previously exchanged heavy metals to be re-eluted, especially zinc and cadmium. Zeolite MAP as an exchanger is relatively unaffected by road salt. There is potential for the use of

  2. Metal ion toxins and brain aquaporin-4 expression: an overview

    Directory of Open Access Journals (Sweden)

    Adriana eXimenes-Da-Silva

    2016-06-01

    Full Text Available Metal ions such as iron, zinc, and manganese are essential to metabolic functions, protein synthesis, neurotransmission, and antioxidant neuroprotective mechanisms. Conversely, non-essential metals such as mercury and lead are sources of human intoxication due to occupational activities or environmental contamination. Essential or non-essential metal accumulation in the central nervous system (CNS results in changes in blood-brain barrier (BBB permeability, as well as triggering microglia activation and astrocyte reactivity and changing water transport through the cells, which could result in brain swelling. Aquaporin-4 is the main water channel in the CNS, is expressed in astrocyte foot processes in brain capillaries and along the circumventricular epithelium in the ventricles, and has important physiological functions in maintaining brain osmotic homeostasis and supporting brain excitability through regulation of the extracellular space. Some evidence has pointed to a role of AQP4 during metal intoxication in the brain, where it may act in a dual form as a neuroprotector or a mediator of the development of oxidative stress in neurons and astrocytes, resulting in brain swelling and neuronal damage. This mini-review presents the way some metal ions affect changes in AQP4 expression in the CNS and discuss the ways in which water transport in brain cells can be involved in brain damage.

  3. Formation of biaxial texture in metal films by selective ion beam etching

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.J. [Department of Materials Science and Engineering, University of Florida, 106 Rhines Hall, P.O. Box 116400, Gainesville, FL 32611 (United States); Norton, D.P. [Department of Materials Science and Engineering, University of Florida, 106 Rhines Hall, P.O. Box 116400, Gainesville, FL 32611 (United States)]. E-mail: dnort@mse.ufl.edu; Selvamanickam, Venkat [IGC-SuperPower, LLC, 450 Duane Avenue, Schenectady, NY 12304 (United States)

    2006-05-15

    The formation of in-plane texture via ion bombardment of uniaxially textured metal films was investigated. In particular, selective grain Ar ion beam etching of uniaxially textured (0 0 1) Ni was used to achieve in-plane aligned Ni grains. Unlike conventional ion beam assisted deposition, the ion beam irradiates the uniaxially textured film surface with no impinging deposition flux. The initial uniaxial texture is established via surface energy minimization with no ion irradiation. Within this sequential texturing method, in-plane grain alignment is driven by selective etching and grain overgrowth. Biaxial texture was achieved for ion beam irradiation at elevated temperature.

  4. Formation of biaxial texture in metal films by selective ion beam etching

    International Nuclear Information System (INIS)

    Park, S.J.; Norton, D.P.; Selvamanickam, Venkat

    2006-01-01

    The formation of in-plane texture via ion bombardment of uniaxially textured metal films was investigated. In particular, selective grain Ar ion beam etching of uniaxially textured (0 0 1) Ni was used to achieve in-plane aligned Ni grains. Unlike conventional ion beam assisted deposition, the ion beam irradiates the uniaxially textured film surface with no impinging deposition flux. The initial uniaxial texture is established via surface energy minimization with no ion irradiation. Within this sequential texturing method, in-plane grain alignment is driven by selective etching and grain overgrowth. Biaxial texture was achieved for ion beam irradiation at elevated temperature

  5. Nuclear quantum effects on adsorption of H2 and isotopologues on metal ions

    Science.gov (United States)

    Savchenko, Ievgeniia; Gu, Bing; Heine, Thomas; Jakowski, Jacek; Garashchuk, Sophya

    2017-02-01

    The nuclear quantum effects on the zero-point energy (ZPE), influencing adsorption of H2 and isotopologues on metal ions, are examined using normal mode analysis of ab initio electronic structure results for complexes with 17 metal cations. The lightest metallic nuclei, Li and Be, are found to be the most 'quantum'. The largest selectivity in adsorption is predicted for Cu, Ni and Co ions. Analysis of the nuclear wavepacket dynamics on the ground state electronic potential energy surfaces (PES) performed for complexes of Li+ and Cu+2 with H2/D2/HD shows that the PES anharmonicity changes the ZPE by up to 9%.

  6. Some ENDOR studies of 3d transition metal ions in semiconductors

    International Nuclear Information System (INIS)

    Engelen, P.P.J.

    1980-01-01

    The author considers 3d transition metal ions substituted in covalent semiconducting crystals. The magnitude of the contact hyperfine field at the 59 Co nucleus in cobalt doped CdS is determined. The results of an ENDOR study of supertransferred hyperfine interactions with nearest neighbour Ga ions in Mn doped GaP are presented. (G.T.H.)

  7. Oxidized graphene as an electrode material for rechargeable metal-ion batteries – a DFT point of view

    International Nuclear Information System (INIS)

    Dobrota, Ana S.; Pašti, Igor A.; Skorodumova, Natalia V.

    2015-01-01

    Graphical abstract: - Abstract: In line with a growing interest in the use of graphene-based materials for energy storage applications and active research in the field of rechargeable metal-ion batteries we have performed a DFT based computational study of alkali metal atoms (Li, Na and K) interaction with an oxidized graphene. The presence of oxygen surface groups (epoxy and hydroxyl) alters the chemisorption properties of graphene. In particular, we observe that the epoxy groups are redox active and enhance the alkali metal adsorption energies by a factor of 2 or more. When an alkali metal atom interacts with hydroxyl-graphene the formation of metal-hydroxide is observed. In addition to a potential boost of metal ion storage capability, oxygen functional groups also prevent the precipitation of the metal phase. By simulating lithiation/de-lithiation process on epoxy-graphenes, it was concluded that the oxidized graphene can undergo structural changes during battery operation. Our results suggest that the content and the type of oxygen surface groups should be carefully tailored to maximize the performance of metal-ion batteries. This is mainly related to the control of the oxidation level in order to provide enough active centers for metal ion storage while preserving sufficient electrical conductivity

  8. U3O8 obtained from metallic uranium

    International Nuclear Information System (INIS)

    Lopez, Marisol; Gonzalez, Alfredo; Pasqualini, Enrique E.

    2003-01-01

    Enriched uranium oxide, U 3 O 8 , used as nuclear powder in MTR's, can be obtained by direct oxidation of metallic uranium at 800 C degrees. Maximum density, 8.2 gr/cm 3 , is achieved after grinding and a high temperature treatment at 1400 C degrees. All the process is highly controllable and performed in dry environments. (author)

  9. Preparation and adsorption behavior for metal ions and humic acid of chitosan derivatives crosslinked by irradiation

    International Nuclear Information System (INIS)

    Zhao Long; Mitomo, H.; Yoshii, F.

    2006-01-01

    Introduction: Removing metal ions and humic acid from water in water treatment has attracted much environment and health interests. Adsorbents, derived from a nature polymer, are desired in the viewpoints of environment-conscious technologies. Recently, some nature materials such as chitin, chitosan and their derivatives have been identified as an attractive option due to their distinctive properties. For an insoluble adsorbent based on these polymers to be obtained over a broad pH range, modification through crosslinking is required. Crosslinking agents such as glutaric dialdehyde and ethylene glycol diglycidyl ether are frequently used for modification. However, these crosslinking agents are not preferred because of their physiological toxicity. Radiation-crosslinking without any additive in the fabrication process results in a high-purity product. In a previous work, we applied ionizing radiation to induce the crosslinking of carboxymethylchitosan under highly concentrated paste-like conditions. The aim of this study is to investigate the adsorption behavior of metal ions, humic acid on irradiation-crosslinked carboxymethylchitosan. Experimental: Irradiation of chitosan samples at paste-like state was done with an electron beam. The solubility test of these crosslinked materials were investigated in acidic, alkaline media, and some organic solvents. Swelling and charged characteristic analyses demonstrated typically pH-sensitive properties of these crosslinked materials. Scanning electron microscopic images showed that the crosslinked samples possessed porous morphological structure. The adsorption studies were carried out by the batch method at room temperature. Adsorption of heavy metal ions (such as Cu 2+ , Cd 2+ ) and humic acid onto crosslinked samples was found to be strongly pH-dependent. Adsorption kinetic studies indicated the rapid removal of metal ions, and humic acid from the aqueous solutions. Also, isothermal adsorption data revealed that Cu 2

  10. Removal of metallic ions from aqueous solutions by fluidized bed fly ashes

    Energy Technology Data Exchange (ETDEWEB)

    Rio, S.; Delebarre, A.; Hequet, V. [Ecole des Mines de Nantes, 44 - Nantes (France); Blondin, J. [Cerchar 62 - Mazingarbe (France)

    2001-07-01

    One of the main constraints deriving from the generation of power by coal combustion is to find some use for the fly ashes instead of disposing of them. Fly ashes from two fluidized bed power plants were tested to remove Pb{sup 2+}, Cu{sup 2+}, Cr (III), Ni{sup 2+}, Zn{sup 2+} and Cr (VI) from aqueous solutions. Experimental design methodology was used to study the removal and the leaching as a function of (i) the water pollutant content, (ii) the metal concentration in water, (iii) the pH of the solution and (iv) the addition of lime to fly ashes. The results show that the percentage of adsorbed ions was more important when they were in contact with silico-aluminous fly ashes than sulfo-calcic fly ashes, except in the case of the ion Ni{sup 2+}. The removal of metallic ions increases with increasing pH. The metallic canons removal accounting for the leaching test was higher when lime was added to silico-aluminous fly ashes during the adsorption. (authors)

  11. Selective Decontamination Effect of Metal Ions in Soil Using Supercritical CO2 and TBP Complex

    International Nuclear Information System (INIS)

    Park, Jihye; Park, Kwangheon; Jung, Wonyoung

    2014-01-01

    Decontamination of soil pollution is difficult because the type of contamination largely depends on the characteristics of the pollutant and the area. Also, existing soil decontamination methods generate large quantities of secondary waste and additional process costs. For this reason, new decontamination methods are always under active investigation. A method involving the use of supercritical carbon dioxide with excellent permeability in place of chemical solvents is currently being studied. Unlike other heavy metals in fission products, uranium is used as fuel, and must be handled carefully. Therefore, in this paper, we studied a supercritical carbon dioxide method for decontaminating heavy metal ions in soil using tri-n-butyl phosphate(TBP), which is well known as a ligand for the extraction of metal ions of actinium. We investigated the decontamination effect of heavy metal ions in the soil using TBP-HNO 3 Complex and supercritical carbon dioxide. The study results showed that when heavy metals in soil are extracted using supercritical carbon dioxide, the extraction efficiency is different according to the type of pollutant metal ions in the soil. When TBP-HNO 3 Complex is used with an extractant, uranium extraction is very effective, but lithium, strontium, and cesium extraction is not effective. Therefore, in the case of a mixture of uranium and other metals such as lithium, strontium, cesium, and so on in soil contaminated by fission product leaks from nuclear power plants, we can selectively decontaminate uranium with supercritical carbon dioxide and TBP-HNO 3 Complex

  12. Detection of heavy metal ions in drinking water using a high-resolution differential surface plasmon resonance sensor.

    Science.gov (United States)

    Forzani, Erica S; Zhang, Haiqian; Chen, Wilfred; Tao, Nongjian

    2005-03-01

    We have built a high-resolution differential surface plasmon resonance (SPR) sensor for heavy metal ion detection. The sensor surface is divided into a reference and sensing areas, and the difference in the SPR angles from the two areas is detected with a quadrant cell photodetector as a differential signal. In the presence of metal ions, the differential signal changes due to specific binding of the metal ions onto the sensing area coated with properly selected peptides, which provides an accurate real-time measurement and quantification of the metal ions. Selective detection of Cu2+ and Ni2+ in the ppt-ppb range was achieved by coating the sensing surface with peptides NH2-Gly-Gly-His-COOH and NH2-(His)6-COOH. Cu2+ in drinking water was tested using this sensor.

  13. Crystal structure of TiNi nanoparticles obtained by Ar ion beam deposition

    International Nuclear Information System (INIS)

    Castro, A. Torres; Cuellar, E. Lopez; Mendez, U. Ortiz; Yacaman, M. Jose

    2008-01-01

    Nanoparticles are a state of matter that have properties different from either molecules or bulk solids, turning them into a very interesting class of materials to study. In the present work, the crystal structure of TiNi nanoparticles obtained by ion beam deposition is characterized. TiNi nanoparticles were obtained from TiNi wire samples by sputtering with Ar ions using a Gatan precision ion polishing system. The TiNi nanoparticles were deposited on a Lacey carbon film that was used for characterization by transmission electron microscopy. The nanoparticles were characterized by high-resolution transmission electron microscopy, high-angle annular dark-field imaging, electron diffraction, scanning transmission electron microscopy and energy-dispersive X-ray spectroscopy. Results of nanodiffraction seem to indicate that the nanoparticles keep the same B2 crystal structure as the bulk material but with a decreased lattice parameter

  14. Ion implantation

    International Nuclear Information System (INIS)

    Dearnaley, Geoffrey

    1975-01-01

    First, ion implantation in semiconductors is discussed: ion penetration, annealing of damage, gettering, ion implanted semiconductor devices, equipement requirements for ion implantation. The importance of channeling for ion implantation is studied. Then, some applications of ion implantation in metals are presented: study of the corrosion of metals and alloys; influence or ion implantation on the surface-friction and wear properties of metals; hyperfine interactions in implanted metals

  15. Wear properties of metal ion implanted 4140 steel

    International Nuclear Information System (INIS)

    Evans, P.J.; Paoloni, F.J.

    1994-01-01

    AISI type 4140 (high tensile) steel has been implanted with tungsten and titanium using a metal vapour vacuum arc ion source. Doses in the range (1-5)x10 16 ionscm -2 were implanted to a depth of approximately 30nm. The relative wear resistance between non-implanted and implanted specimens has been estimated using pin-on-disc and abrasive wear tests. Implantation of titanium decreased the area of wear tracks by a factor of 5 over unimplanted steel. In some cases the steel was also hardened by a liquid carburization treatment before implantation. Abrasion tests revealed a further improvement in wear resistance on this material following ion irradiation. ((orig.))

  16. Remediation of groundwater containing radionuclides and heavy metals using ion exchange and the AlgaSORB reg-sign biosorbent system

    International Nuclear Information System (INIS)

    Feiler, H.D.; Darnall, D.W.

    1991-01-01

    Bio-Recovery Systems, Inc. (BRS) studied the application of an immobilized algal biomass, termed AlgaSORB reg-sign, which has high affinity for heavy metal ions to DOE-contaminated groundwaters. The material can be packed into columns similar to commercial ion exchange resins. Dilute solutions containing heavy metals are passed through columns where metals are absorbed by the AlgaSORB reg-sign resins. Once saturated, metal ions can be stripped from the resin biomass in a highly concentrated solution. Groundwaters contaminated with heavy metal ions from three different Department of Energy (DOE) sites: Savannah River, Hanford and the Oak Ridge Y-12 Plant were studied. The objective was to perform bench-scale treatability studies to establish treatment protocols and to optimize an AlgaSORB reg-sign/ion exchange technology system to remove and recover toxic metal ions from these contaminated groundwaters. The specialty ion exchange/AlgaSORB reg-sign resins tested in these studies show promise for selectively removing chromium, mercury and uranium from contaminated groundwater at DOE sites. The data show that effluents which satisfy the allowable metal ion limits are possible and most likely achievable. The use of these highly selective resins also offer advantages in terms of cost/benefit, risk and scheduling. Their high selectivity allows for high capacity and opportunities for recovery of removed constituents due to high pollutant concentration possible (3 to 4 orders of magnitude). Ion exchange is a proven technology which is easily automated and can be cost-effective, depending on the application

  17. Hydration number of alkali metal ions determined by insertion in a conducting polymer

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2008-01-01

    of all other water molecules whose properties are still influenced significantly by the cation. Knowing the hydration number is important when considering, for instance, the transport of Na+ and K+ in biological cell membranes, since their different behavior may depend on the details of ion hydration....... The solvation of alkali metal ions has been discussed for many years without a clear consensus. This work presents a systematic study of the hydration numbers of the 5 alkali metal ions, using the electrochemical insertion of the ions in a conducting polymer (polypyrrole containing the large immobile anion DBS...... direct calculation of the number of M+ ions entering the film, and therefore the inserted M+ mass. The mass of the water molecules is calculated as a difference. The results yield the following primary hydration numbers: Li+: 5.5-5.6; Na+: 4.0-4.1; K+: 2.0-2.5; Rb+: 0.6-1.2; Cs+: ~0. The most important...

  18. Surface modification of ceramics and metals by ion implantation combined with plasma irradiation

    International Nuclear Information System (INIS)

    Miyagawa, Soji; Miyagawa, Yoshiko; Nakao, Setsuo; Ikeyama, Masami; Saitoh, Kazuo

    2000-01-01

    To develop a new surface modification technique using ion implantation combined with plasma irradiation, thin film formation by IBAD (Ion Beam Assisted Deposition) and atom relocation processes such as radiation enhanced diffusion and ion beam mixing under high dose implantation have been studied. It was confirmed that the computer simulation code, dynamic-SASAMAL (IBAD version) developed in this research, is quite useful to evaluate ballistic components in film formation by high dose implantation on ceramics and metals, by ion beam mixing of metal-ceramics bi-layer and by the IBAD method including hydrocarbon deposition. Surface modification process of SiC by simultaneous irradiation of ions with a radical beam has also been studied. A composite of SiC and β-Si 3 N 4 was found to be formed on a SiC surface by hot implantation of nitrogen. The amount of β- Si 3 N 4 crystallites increased with increasing the dosage of the hydrogen radical beam during nitrogen implantation. (author)

  19. Improved oxidation resistance of group VB refractory metals by Al+ ion implantation

    International Nuclear Information System (INIS)

    Hampikian, J.M.

    1996-01-01

    Aluminum ion implantation of vanadium, niobium, and tantalum improved the metals' oxidation resistances at 500 C and 735 C. Implanted vanadium oxidized only to one-third the extent of unimplanted vanadium when exposed at 500 C to air. The oxidative weight gains of implanted niobium and tantalum proved negligible when measured at 500 C and for times sufficient to fully convert the untreated metals to their pentoxides. At 735 C, implantation of vanadium only slightly retarded its oxidation, while oxidative weight gains of niobium and tantalum were reduced by factors of 3 or more. Implanted niobium exhibited weight gain in direct proportion to oxidation time squared at 735 C. Microstructural examination of the metals implanted with selected fluences of the 180 kV aluminum ions showed the following. The solubility limit of aluminum is extended by implantation, the body centered cubic (bcc) phases being retained to ∼60 at. pct Al in all three metals. The highest fluence investigated, 2.4 x 10 22 ions/m 2 , produced an ∼400-nm layer of VAl 3 beneath the surface of vanadium, and ∼300-nm layers of an amorphous phase containing ∼70 at. pct Al beneath the niobium and tantalum surfaces. All three metals, implanted to this fluence and annealed at 600 C, contained tri-aluminides, intermetallic compounds known for their oxidation resistances. Specimens implanted to this fluence were thus selected for the oxidation measurements

  20. The Gellyfish: an in-situ equilibrium-based sampler for determining multiple free metal ion concentrations in marine ecosystems

    Science.gov (United States)

    Free metal ions are usually the most bioavailable and toxic metal species to aquatic organisms, but they are difficult to measure because of their extremely low concentrations in the marine environment. Many of the current methods for determining free metal ions are complicated a...

  1. Asparagus cochinchinensis Extract Alleviates Metal Ion-Induced Gut Injury in Drosophila: An In Silico Analysis of Potential Active Constituents

    Directory of Open Access Journals (Sweden)

    Weiyu Zhang

    2016-01-01

    Full Text Available Metal ions and sulfate are components of atmospheric pollutants that have diverse ways of entering the human body. We used Drosophila as a model to investigate the effect of Asparagus cochinchinensis (A. cochinchinensis extracts on the gut and characterized gut homeostasis following the ingestion of metal ions (copper, zinc, and aluminum. In this study, we found that the aqueous A. cochinchinensis extract increased the survival rate, decreased epithelial cell death, and attenuated metal ion-induced gut morphological changes in flies following chronic exposure to metal ions. In addition, we screened out, by network pharmacology, six natural products (NPs that could serve as putative active components of A. cochinchinensis that prevented gut injury. Altogether, the results of our study provide evidence that A. cochinchinensis might be an effective phytomedicine for the treatment of metal ion-induced gut injury.

  2. Nano-size metallic oxide particle synthesis in Fe-Cr alloys by ion implantation

    Science.gov (United States)

    Zheng, C.; Gentils, A.; Ribis, J.; Borodin, V. A.; Delauche, L.; Arnal, B.

    2017-10-01

    Oxide Dispersion Strengthened (ODS) steels reinforced with metal oxide nanoparticles are advanced structural materials for nuclear and thermonuclear reactors. The understanding of the mechanisms involved in the precipitation of nano-oxides can help in improving mechanical properties of ODS steels, with a strong impact for their commercialization. A perfect tool to study these mechanisms is ion implantation, where various precipitate synthesis parameters are under control. In the framework of this approach, high-purity Fe-10Cr alloy samples were consecutively implanted with Al and O ions at room temperature and demonstrated a number of unexpected features. For example, oxide particles of a few nm in diameter could be identified in the samples already after ion implantation at room temperature. This is very unusual for ion beam synthesis, which commonly requires post-implantation high-temperature annealing to launch precipitation. The observed particles were composed of aluminium and oxygen, but additionally contained one of the matrix elements (chromium). The crystal structure of aluminium oxide compound corresponds to non-equilibrium cubic γ-Al2O3 phase rather than to more common corundum. The obtained experimental results together with the existing literature data give insight into the physical mechanisms involved in the precipitation of nano-oxides in ODS alloys.

  3. Magnetite–hematite nanoparticles prepared by green methods for heavy metal ions removal from water

    International Nuclear Information System (INIS)

    Ahmed, M.A.; Ali, S.M.; El-Dek, S.I.; Galal, A.

    2013-01-01

    Graphical abstract: The negatively charged cubic magnetite nanoparticles, prepared by the coprecipitation method in N 2 atmosphere, can adsorb up to 99% of the positively charged toxic heavy metal ions at a proper pH value. -- Highlights: • Mixed magnetite–hematite nanoparticles were synthesized via different routes. • Prepared samples were characterized by XRD, HRTEM, BET and magnetic hysteresis. • The material was employed as a sorbent for removal of some heavy metal ions from water. • The effects of pH and the contact time on the adsorption process were studied and optimized. -- Abstract: Mixed magnetite–hematite nanoparticles were synthesized via different routes such as, coprecipitation in air and N 2 atmosphere, citrate–nitrate, glycine–nitrate and microwave-assisted citrate methods. The prepared samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), BET measurements and magnetic hysteresis. XRD data showed the formation of magnetite–hematite mixture with different compositions according to the synthesis method. The particle size was in the range of 4–52 nm for all the prepared samples. From HRTEM micrographs, it was found that, the synthesis method affects the moropholgy of the prepared samples in terms of crystallinity and porosity. The magnetite–hematite mixture was employed as a sorbent material for removal of some heavy metal ions from water such as lead(II), cadmium(II) and chromium(III). The effects of pH value and the contact time on the adsorption process were studied and optimized in order to obtain the highest possible adsorption efficiency of the magnetite–hematite mixture. The effect of the synthesis method of the magnetite–hematite mixture on the adsorption process was also investigated. It was found that samples prepared by the coprecipitation method had better adsorption efficiency than those prepared by other combustion methods

  4. A study of enhanced diffusion during high dose high flux pulsed metal ion implantation into steel and aluminium

    International Nuclear Information System (INIS)

    Zhang Tonghe; Ji Chengzhou; Shen Jinghua; Chen Jun

    1992-01-01

    The depth profiles of metal ions implanted into steel and aluminium were measured by Rutherford backscattering (RBS). The ions of Mo, W and Y, produced by a metal vapour vacuum are ion source (MEVVA) were implanted at an energy range from 25 to 50 keV for doses of (2-5)x10 17 cm -2 into H13 steel and aluminium. Beam currents were from 0.5 to 1.0 A. The beam flux is in the range of 25 to 75 μAcm -2 . In order to simulate the profiles, a formula which includes the sputtering yield, diffusion coefficients and reaction rate was obtained. The results demonstrate that the penetration depth and retained dose increase with increasing beam flux for Mo implanted into aluminium. The peak concentration of Mo implanted H13 steel increases with increasing ion flux. In contrast to this for Y implantation into steel, the peak concentration of Y decreases with increasing ion flux. For an ion flux of 25 μAcm -2 for Mo, Y and W implantation into steel, the penetration depth and retained dose are 3-5 times greater than the theoretical values. The diffusion coefficients are about 10 -16 to 10 -15 s -1 . If the ion flux is greater than 47 μAcm -2 , the penetration depth and retained dose are 5 to 10 times greater than the theoretical values for Mo implanted aluminium. The diffusion coefficients increase with increasing ion flux for Mo implanted aluminium. The diffusion coefficients hardly change with increasing ion flux for Y and Mo implanted H13 steel. The retained dose increases 0.43 to 1.16 times for Y implanted steel for an ion flux of 25 μAcm -2 . Finally, the influence of phases precipitates, reaction rate and diffusion on retained dose, diffusion coefficient and penetration depth are discussed. (orig.)

  5. Effect of carbon ion implantation on the tribology of metal-on-metal bearings for artificial joints

    Directory of Open Access Journals (Sweden)

    Koseki H

    2017-05-01

    Full Text Available Hironobu Koseki,1 Masato Tomita,2 Akihiko Yonekura,2 Takashi Higuchi,1 Sinya Sunagawa,2 Koumei Baba,3,4 Makoto Osaki2 1Department of Locomotive Rehabilitation Science, Unit of Rehabilitation Sciences, 2Department of Orthopedic Surgery, Nagasaki University Graduate School of Biomedical Sciences, Sakamoto, Nagasaki, Japan; 3Industrial Technology Center of Nagasaki, Ikeda, Omura, Nagasaki, Japan; 4Affiliated Division, Nagasaki University School of Engineering, Bunkyo, Nagasaki, Japan Abstract: Metal-on-metal (MoM bearings have become popular due to a major advantage over metal-on-polymer bearings for total hip arthroplasty in that the larger femoral head and hydrodynamic lubrication of the former reduce the rate of wear. However, concerns remain regarding adverse reactions to metal debris including metallosis caused by metal wear generated at the taper-head interface and another modular junction. Our group has hypothesized that carbon ion implantation (CII may improve metal wear properties. The purpose of this study was to investigate the wear properties and friction coefficients of CII surfaces with an aim to ultimately apply these surfaces to MoM bearings in artificial joints. CII was applied to cobalt-chromium-molybdenum (Co-Cr-Mo alloy substrates by plasma source ion implantation. The substrates were characterized using scanning electron microscopy and a 3D measuring laser microscope. Sliding contact tests were performed with a simple geometry pin-on-plate wear tester at a load of 2.5 N, a calculated contact pressure of 38.5 MPa (max: 57.8 MPa, a reciprocating velocity of 30 mm/s, a stroke length of 60 mm, and a reciprocating cycle count of 172,800 cycles. The surfaces of the CII substrates were generally featureless with a smooth surface topography at the same level as untreated Co-Cr-Mo alloy. Compared to the untreated Co-Cr-Mo alloy, the CII-treated bearings had lower friction coefficients, higher resistance to catastrophic damage, and

  6. Irradiation of tungsten with metallic diatomic molecular ions: atomic-resolution observations of depleted zones

    International Nuclear Information System (INIS)

    Pramanik, D.; Seidman, D.N.

    1982-08-01

    Direct evidence, on an atomic scale, is presented for the enhancement of damage production per projectile ion in diatomic metallic molecular ion (dimer) irradiations of tungsten as compared to monatomic metallic ion (monomer) irradiations. Irradiations were performed in situ at less than or equal to 10 K, in a field-ion microscope, employing 20 keV Ag + or W + monomer ions and the results are compared with 40 keV W 2 + or Ag 2 + dimer ion bombardments; the average energy per ion was 20 keV. First, in the near-surface region the depleted zones produced by the W 2 + dimer ions give rise to void-like contrast effects. The W + monomer ions do not produce this void-like damage. The existence of voids was explained employing a nucleation and diffusion-limited growth model which suggests that the growth can occur on a time scale -9 s, if the effective diffusivity of an atom in the fully-developed collision cascade is > 3 x 10 -4 cm 2 s -1 . Second, by counting the number of vacancies in individual depleted zones, produced by the different ions, it was demonstrated that the number of vacancies produced per incoming ion of the dimer is 1.55 times greater than the number of vacancies produced per monomer ion

  7. Binding of heavy metal ions in aggregates of microbial cells, EPS and biogenic iron minerals measured in-situ using metal- and glycoconjugates-specific fluorophores

    Science.gov (United States)

    Hao, Likai; Guo, Yuan; Byrne, James M.; Zeitvogel, Fabian; Schmid, Gregor; Ingino, Pablo; Li, Jianli; Neu, Thomas R.; Swanner, Elizabeth D.; Kappler, Andreas; Obst, Martin

    2016-05-01

    Aggregates consisting of bacterial cells, extracellular polymeric substances (EPS) and Fe(III) minerals formed by Fe(II)-oxidizing bacteria are common at bulk or microscale chemical interfaces where Fe cycling occurs. The high sorption capacity and binding capacity of cells, EPS, and minerals controls the mobility and fate of heavy metals. However, it remains unclear to which of these component(s) the metals will bind in complex aggregates. To clarify this question, the present study focuses on 3D mapping of heavy metals sorbed to cells, glycoconjugates that comprise the majority of EPS constituents, and Fe(III) mineral aggregates formed by the phototrophic Fe(II)-oxidizing bacteria Rhodobacter ferrooxidans SW2 using confocal laser scanning microscopy (CLSM) in combination with metal- and glycoconjugates-specific fluorophores. The present study evaluated the influence of glycoconjugates, microbial cell surfaces, and (biogenic) Fe(III) minerals, and the availability of ferrous and ferric iron on heavy metal sorption. Analyses in this study provide detailed knowledge on the spatial distribution of metal ions in the aggregates at the sub-μm scale, which is essential to understand the underlying mechanisms of microbe-mineral-metal interactions. The heavy metals (Au3+, Cd2+, Cr3+, CrO42-, Cu2+, Hg2+, Ni2+, Pd2+, tributyltin (TBT) and Zn2+) were found mainly sorbed to cell surfaces, present within the glycoconjugates matrix, and bound to the mineral surfaces, but not incorporated into the biogenic Fe(III) minerals. Statistical analysis revealed that all ten heavy metals tested showed relatively similar sorption behavior that was affected by the presence of sorbed ferrous and ferric iron. Results in this study showed that in addition to the mineral surfaces, both bacterial cell surfaces and the glycoconjugates provided most of sorption sites for heavy metals. Simultaneously, ferrous and ferric iron ions competed with the heavy metals for sorption sites on the organic

  8. Hollow carbon sphere/metal oxide nanocomposites anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Wenelska, K.; Ottmann, A.; Schneider, P.; Thauer, E.; Klingeler, R.; Mijowska, E.

    2016-01-01

    HCS (Hollow carbon spheres) covered with metal oxide nanoparticles (SnO_2 and MnO_2, respectively) were successfully synthesized and investigated regarding their potential as anode materials for lithium-ion batteries. Raman spectroscopy shows a high degree of graphitization for the HCS host structure. The mesoporous nature of the nanocomposites is confirmed by Brunauer–Emmett–Teller analysis. For both metal oxides under study, the metal oxide functionalization of HCS yields a significant increase of electrochemical performance. The charge capacity of HCS/SnO_2 is 370 mA hg"−"1 after 45 cycles (266 mA hg"−"1 in HCS/MnO_2) which clearly exceeds the value of 188 mA hg"−"1 in pristine HCS. Remarkably, the data imply excellent long term cycling stability after 100 cycles in both cases. The results hence show that mesoporous HCS/metal oxide nanocomposites enable exploiting the potential of metal oxide anode materials in Lithium-ion batteries by providing a HCS host structure which is both conductive and stable enough to accommodate big volume change effects. - Highlights: • Strategy to synthesize hollow carbon spheres decorated by metal oxides nanoparticles. • High-performance of HCS/MOx storage as mesoporous hybrid material. • The results hence demonstrate high electrochemical activity of the HCS/MOx.

  9. Line profile analyses of rhodium metal obtained by decomposition of rhodium carbonyl

    International Nuclear Information System (INIS)

    Chandra, D.; Mandalia, H.; Garner, M.L.; Blakely, M.K.; Lau, K.H.

    1995-01-01

    Metal carbonyls are important for chemical vapor deposition (CVD) of metals and alloys and formation of high surface area metallic particles which have potential applications as catalysts. Rhodium carbonyl [Rh 6 (CO) 16 ] produces high surface area metallic particles whose structure has been reported as monoclinic (I2/a) with lattice dimensions, a=17.00(±0.03)Angstrom, b=9.78(±0.02)Angstrom, c=17.53(±0.03)Angstrom and Β=121 degrees 45' ± 30' at room temperature. Generally, metal carbonyl crystals dissociate under vacuum as carbonyl gas and decompose to metallic crystals and carbon monoxide at higher temperatures. However, the behavior of rhodium carbonyl crystals is different; they decompose directly to metallic rhodium without the formation of rhodium carbonyl gas in vacuum. Several residual fine grains of rhodium metal are found after the decomposition in vacuum at relatively low temperatures. The metallic samples of rhodium were obtained from vapor pressure experiments using torsion Knudsen-effusion apparatus. X-ray diffraction analyses performed on these gains showed severely broadened Bragg reflections indicative of small particle size and/or lattice microgram. In this study, a comparison of lattice strains and domain sizes obtained by integral breadth and Fourier methods has been made. In addition a comparison of the lattice strains and domain sizes has been made between the Cauchy, Gaussian, Cauchy-Gaussian and Aqua integral breadth methods

  10. Continuum radiation emitted from transition metals under ion bombardment

    International Nuclear Information System (INIS)

    El Boujlaidi, A.; Kaddouri, A.; Ait El Fqih, M.; Hammoum, K.; Aouchiche, H.

    2012-01-01

    Optical emission of transition metals has been studied during 5 keV Kr + ions bombardment within and without oxygen atmosphere in the colliding chamber. The observed spectra consist of a series of discrete lines superimposed on a broad continuum. Generally, the emission intensity was influenced by the presence of oxygen giving rise to transient effects as well as to an increase in the line intensity. The behaviours of spectral lines were successfully explained in term of electron-transfer process between the excited sputtered atom and the solid surface. In this work, we have focused our study on the continuous radiation emitted during ion bombardment. The experimental results suggest that the continuum emission depends on the nature of metal and very probably related to its electronic structure. The collective deactivation of 3d-shell electrons appears to play a role in the emission of this radiation. The observed enhancement in the presence of oxygen is probably due to a significant contribution of the oxide molecules. (authors)

  11. Effect of metal ions on de novo aggregation of full-length prion protein

    International Nuclear Information System (INIS)

    Giese, Armin; Levin, Johannes; Bertsch, Uwe; Kretzschmar, Hans

    2004-01-01

    It is well established that the prion protein (PrP) contains metal ion binding sites with specificity for copper. Changes in copper levels have been suggested to influence incubation time in experimental prion disease. Therefore, we studied the effect of heavy metal ions (Cu 2+ , Mn 2+ , Ni 2+ , Co 2+ , and Zn 2+ ) in vitro in a model system that utilizes changes in the concentration of SDS to induce structural conversion and aggregation of recombinant PrP. To quantify and characterize PrP aggregates, we used fluorescently labelled PrP and cross-correlation analysis as well as scanning for intensely fluorescent targets in a confocal single molecule detection system. We found a specific strong pro-aggregatory effect of Mn 2+ at low micromolar concentrations that could be blocked by nanomolar concentration of Cu 2+ . These findings suggest that metal ions such as copper and manganese may also affect PrP conversion in vivo

  12. Effects of metal ions on biomass and 5-aminolevulinic acid production in Rhodopseudomonas palustris wastewater treatment.

    Science.gov (United States)

    Liu, Shuli; Zhang, Guangming; Li, Jianzheng; Li, Xiangkun; Zhang, Jie

    2016-01-01

    This work investigated the effects of eight metal ions on Rhodopseudomonas palustris growth and 5-aminolevulinic acid (ALA) yield in wastewater treatment. Results show that metal ions (Mg(2+) of 15 mmol/L, Fe(2+) of 400 μmol/L, Co(2+) of 4 μmol/L, Ni(2+) of 8 μmol/L and Zn(2+) of 4 μmol/L) could effectively improve the chemical oxygen demand (COD) removal, Rp. palustris biomass and ALA yield. The highest ALA yield of 13.1 mg/g-biomass was achieved with Fe(2+) of 400 μmol/L. ALA yields were differentially increased under different metal ions in the following order: Fe(2+) group > Mg(2+) group > Co(2+) group = Ni(2+) group > Zn(2+) group = Mo(2+) group > control. Cu(2+) and Mn(2+) inhibited Rp. palustris growth and ALA production. Mechanism analysis revealed that metal ions changed ALA yields by influencing the activities of ALA synthetase and ALA dehydratase.

  13. Potential release of in vivo trace metals from metallic medical implants in the human body: from ions to nanoparticles--a systematic analytical review.

    Science.gov (United States)

    Matusiewicz, Henryk

    2014-06-01

    Metal ion release from metallic materials, e.g. metallic alloys and pure metals, implanted into the human body in dental and orthopedic surgery is becoming a major cause for concern. This review briefly provides an overview of both metallic alloys and pure metals used in implant materials in dental and orthopedic surgery. Additionally, a short section is dedicated to important biomaterials and their corrosive behavior in both real solutions and various types of media that model human biological fluids and tissues. The present review gives an overview of analytical methods, techniques and different approaches applied to the measurement of in vivo trace metals released into body fluids and tissues from patients carrying metal-on-metal prostheses and metal dental implants. Reference levels of ion concentrations in body fluids and tissues that have been determined by a host of studies are compiled, reviewed and presented in this paper. Finally, a collection of published clinical data on in vivo released trace metals from metallic medical implants is included. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  14. Ultrasensitive and simultaneous detection of heavy metal ions based on three-dimensional graphene-carbon nanotubes hybrid electrode materials

    International Nuclear Information System (INIS)

    Huang, Hui; Chen, Ting; Liu, Xiuyu; Ma, Houyi

    2014-01-01

    Highlights: • Three-dimensional graphene-MWCNTs nanocomposites were prepared. • Graphene-MWCNTs based electrochemical sensor was used to detect heavy metal ions for the first time. • The proposed sensor was certified capable for real sample with satisfactory results. - Abstract: A green and facile method was developed to prepare a novel hybrid nanocomposite that consisted of one-dimensional multi-walled carbon nanotubes (MWCNTs) and two-dimensional graphene oxide (GO) sheets. The as-prepared three-dimensional GO–MWCNTs hybrid nanocomposites exhibit excellent water-solubility owing to the high hydrophilicity of GO components; meanwhile, a certain amount of MWCNTs loaded on the surface of GO sheets through π–π interaction seem to be “dissolved” in water. Moreover, the graphene(G)-MWCNTs nanocomposites with excellent conductivity were obtained conveniently by the direct electrochemical reduction of GO–MWCNTs nanocomposites. Seeing that there is a good synergistic effect between MWCNTs and graphene components in enhancing preconcentration efficiency of metal ions and accelerating electron transfer rate at G-MWCNTs/electrolyte interface, the G-MWCNTs nanocomposites possess fast, simultaneous and sensitive detection performance for trace amounts of heavy metal ions. The electrochemical results demonstrate that the G-MWCNTs nanocomposites can act as a kind of practical sensing material to simultaneously determine Pb 2+ and Cd 2+ ions in terms of anodic stripping voltammetry (ASV). The linear calibration plots for Pb 2+ and Cd 2+ ranged from 0.5 μg L −1 to 30 μg L −1 . The detection limits were determined to be 0.2 μg L −1 (S/N = 3) for Pb 2+ and 0.1 μg L −1 (S/N = 3) for Cd 2+ in the case of a deposition time of 180 s. It is worth mentioning that the G-MWCNTs modified electrodes were successfully applied to the simultaneous detection of Cd 2+ and Pb 2+ ions in real electroplating effluent samples containing lots of surface active impurities

  15. Coordination kinetics of different metal ions with the amidoximated polyacrylonitrile nanofibrous membranes and catalytic behaviors of their complexes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fu; Dong, Yong Chun; Kang, Wei Min; Cheng, Bowen; Qu, Xiang; Cui, Guixin [School of Textiles, Tianjin Polytechnic University, Tianjin (China)

    2016-12-15

    Two transition metal ions (Fe{sup 3+} and Cu{sup 2+}) and a rare earth metal ion (Ce{sup 3+}) were selected to coordinate with amidoximated polyacrylonitrile (PAN) nanofibrous membrane for preparing three metal modified PAN nanofibrous membrane complexes (M-AO-n-PANs, M = Fe, Cu, or Ce) as the heterogeneous Fenton catalysts for the dye degradation in water under visible irradiation. The coordination kinetics of three metal ions with modified PAN nanofibrous membranes was studied and the catalytic properties of the resulting complexes were also compared. The results indicated that increasing metal ion concentrations in solution or higher coordination temperature led to a significant increase in metal content, particularly in Fe and Cu contents of the complexes. Their coordination process could be described using Langmuir isotherm and pseudo-second-order kinetic equations. Moreover, Fe-AO-n-PAN had the best photocatalytic efficiency for the dye degradation in acidic medium, but a lower photocatalytic activity than Cu-AO-n-PAN in alkali medium.

  16. Separation and Extraction of Some Heavy and Toxic Metal Ions from Their Wastes by Ionic Membranes

    International Nuclear Information System (INIS)

    El-Sayed Hegazy, A.; Kamal, H.; Mahmoud, Gh. A.; Khalifa, N.A.

    1999-01-01

    Preparation and characterisation of a series of ion-exchange membranes for the purpose of separation and extraction of some heavy and toxic metal ions from their wastes have been studied. Such ion exchange membranes prepared by γ-radiation grafting of acrylonitrile (AN) and vinyl acetate (VAc) in a binary monomers mixture onto low density polyethylene (LDPE) using direct technique of grafting. The reaction conditions at which grafting process proceeds successfully have been determined. Many modification treatments have been attempted for the prepared membranes to improve their ion-exchange properties. The possibility of their practical use in waste water treatment from some heavy and toxic metal ions such as Pb 2+ , Cd 2+ ,Cu 2+ ,Fe 3+ ,Sr 2+ and Li + have been investigated. These grafted membranes showed great promise for its use in the field of extraction and removal of some heavy and toxic metals from their wastes

  17. Thermodynamic properties of heavy ion heated refractory metals; Thermodynamische Eigenschaften von schwerionengeheizten hochschmelzenden Metallen

    Energy Technology Data Exchange (ETDEWEB)

    Hug, Alexander

    2011-05-04

    Knowledge of basic physical properties of matter in high-energy-density (HED) states such as the equation-of-state (EOS) is of fundamental importance for various branches of basic and applied physics. However, such matter under extreme conditions of temperature and pressure - also called ''warm dense matter'' (WDM) - can only be generated in dynamic experiments employing the most powerful drivers. At the high temperature experimental area HHT of the GSI Helmholtzzentrum fuer Schwerionenforschung (Darmstadt, Germany), intense beams of energetic heavy ions are used for this purpose. The aim of this work is to study thermophysical properties of refractory metals in hot solid and liquid states by precise temperature measurements. In order to identify the melting plateau and to limit the maximum target temperature to the region of interest, relatively long (one microsecond) bunches of uranium and xenon ions have been used to heat initially solid samples. The intense ion beams were focused on a millimetre spot at the target in order to achieve uniform conditions. The temperature on the target surface was determined by analysing thermal radiation emitted from a 0.03 mm{sup 2} area at five different wavelengths. In order to obtain the physical temperature, one has to measure not only the thermal radiation but also the emissivity, ε(T,λ) of the target surface which is not known ab initio. For this purpose, a set-up for direct target reflection measurement was designed and embedded into the fast multichannel pyrometer system. The reflection signal provides the necessary information about modifications of the target surface properties during the interaction with the ion beam. Beside the pyrometric and reflection measurement set-ups, various hardware and software components of the data acquisition system for the heavy-ion beam driven experiments were substantially enhanced. The emissivity was also obtained by identifying the melting plateau and using the

  18. Extraction of metal ions by neutral β-diphosphoramides

    International Nuclear Information System (INIS)

    Madic, C.

    1990-01-01

    The extracting ability of β-diphosphoramides of the type R-N[P(O)(NMe 2 ) 2 ] 2 with R=-CH 3 (NIPA), -C 12 H 25 (ODIPA), or -C 16 H 33 (OHDIPA) for metal ions such as lanthanides, uranyl, and the transuranium elements Am(III) and Pu(IV) has been studied. Extraction yields depend on the nature of the ligand, the organic diluent (nitromethane, kerosene, tert-butylbenzene), the concentration of nitric acid in the aqueous phase, and the ligand-to-metal ratio, Q. The results show that the bidentate phosphoramides are very efficient extractants for all of the metals studied, even at low ratios Q. The presence of nitric acid generally enhances the extraction yields. On the other hand, selectivity is rather poor with these ligands. A particular effort has been made to determine the nature of extracted species by NMR spectroscopy

  19. Detection of heavy metal ions in contaminated water by surface plasmon resonance based optical fibre sensor using conducting polymer and chitosan.

    Science.gov (United States)

    Verma, Roli; Gupta, Banshi D

    2015-01-01

    Optical fibre surface plasmon resonance (SPR) based sensor for the detection of heavy metal ions in the drinking water is designed. Silver (Ag) metal and indium tin oxide (ITO) are used for the fabrication of the SPR probe which is further modified with the coating of pyrrole and chitosan composite. The sensor works on the wavelength interrogation technique and is capable of detecting trace amounts of Cd(2+), Pb(2+), and Hg(2+) heavy metal ions in contaminated water. Four types of sensing probes are fabricated and characterised for heavy metal ions out of these pyrrole/chitosan/ITO/Ag coated probe is found to be highly sensitive among all other probes. Further, the cadmium ions bind strongly to the sensing surface than other ions and due to this the sensor is highly sensitive for Cd(2+) ions. The sensor's performance is best for the low concentrations of heavy metal ions and its sensitivity decreases with the increasing concentration of heavy metal ions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. P and Si functionalized MXenes for metal-ion battery applications

    KAUST Repository

    Zhu, Jiajie; Schwingenschlö gl, Udo

    2017-01-01

    MXenes are a family of two-dimensional materials, composed of early transition metal carbides, nitrides, and carbonitrides, with great potential in energy storage systems, in particular in electrodes for Li, Na, K-ion batteries. However, so far

  1. Dimeric Complexes of Tryptophan with M2+ Metal Ions

    NARCIS (Netherlands)

    Dunbar, R. C.; Steill, J. D.; Polfer, N. C.; Oomens, J.

    2009-01-01

    IRMPD spectroscopy using the FELIX free electron laser and a Fourier transform ICR mass spectrometer was used to characterize the structures of electrosprayed dimer complexes M(2+)Trp(2) of tryptophan with a series of eight doubly charged metal ions, including alkaline earths Ca, Sr, and Ba, and

  2. The effect of hydrogen peroxide concentration on metal ion release from dental casting alloys.

    Science.gov (United States)

    Al-Salehi, S K; Hatton, P V; Johnson, A; Cox, A G; McLeod, C

    2008-04-01

    There are concerns that tooth bleaching agents may adversely affect dental materials. The aim of this study was to test the hypothesis that increasing concentrations of hydrogen peroxide (HP) are more effective than water at increasing metal ion release from two typical dental casting alloys during bleaching. Discs (n = 28 for each alloy) were prepared by casting and heat treated to simulate a typical porcelain-firing cycle. Discs (n = 7) of each alloy were immersed in either 0%, 3%, 10% or 30% (w/v) HP solutions for 24 h at 37 degrees C. Samples were taken for metal ion release determination using inductively coupled plasma-mass spectrometry and the data analysed using a two-way anova followed by a one-way anova. The surface roughness of each disc was measured using a Talysurf contact profilometer before and after bleaching and the data analysed using a paired t-test. With the exception of gold, the differences in metal ion concentration after treatment with 0% (control) and each of 3%, 10% and 30% HP (w/v) were statistically significant (P alloys increased with increasing HP concentrations (over 3000% increase in Ni and 1400% increase in Pd ions were recorded when HP concentration increased from 0% to 30%). Surface roughness values of the samples before and after bleaching were not significantly different (P > 0.05) Exposure of the two dental casting alloys to HP solutions increased metal ion release of all the elements except gold.

  3. Multiply charged ions from solid substances with the mVINIS Ion Source

    International Nuclear Information System (INIS)

    Dragani, I; Nedeljkovi, T; Jovovi, J; Siljegovic, M; Dobrosavljevic, A

    2007-01-01

    We have used the well known metal-ions-from-volatile-compounds (MIVOC) method at the mVINIS Ion Source to produce the multiply charged ion beams form solid substances. Based on this method the very intense and stable multiply charged ion beams of several solid substances having the high melting points were extracted. The ion yields and the spectra of multiply charged ion beams obtained from solid materials like Fe and Hf will be presented. We have utilized the multiply charged ion beams from solid substances to irradiate the polymers, fullerenes and glassy carbon at the low energy channel for modification of materials

  4. A comparative study of the magnetization in transition metal ion doped CeO2, TiO2 and SnO2 nanoparticles

    Science.gov (United States)

    Apostolov, A. T.; Apostolova, I. N.; Wesselinowa, J. M.

    2018-05-01

    Using the microscopic s-d model taking into account anharmonic spin-phonon interactions we have studied the magnetic properties of Co and Cu ion doped CeO2 and TiO2 nanoparticles and compared them with those of SnO2. By Co-doping there is a maximum in the magnetization M(x) curve for all nanoparticles observed in the most transition metal doped ones. The s-d interaction plays an important role by the decrease of M at higher dopant concentration. We have discussed the magnetization in dependence of different model parameters. By small Cu-ion doping there are some differences. In CeO2M decreases with the Cu-concentration, whereas in TiO2 and SnO2M increases. For higher Cu dopant concentrations M(X) decreases in TiO2 nanoparticles. We obtain room temperature ferromagnetism also in Zn doped CeO2, TiO2 and SnO2 nanoparticles, i.e. in non-transition metal ion doped ones. The different behavior of M in Co and Cu doped nanoparticles is due to a combination effect of multivalent metal ions, oxygen vacancies, different radius of cation dopants, connection between lattice and magnetism, as well as competition between the s-d and d-d ferromagnetic or antiferromagnetic interactions.

  5. Metal ion complex formation in small lakes of the Western Siberian Arctic zone

    Science.gov (United States)

    Kremleva, Tatiana; Dinu, Marina

    2017-04-01

    The paper is based on joint investigation of the Tyumen State University (Russia, Tyumen) and the Geochemistry and Analytical Chemistry Vernadsky Institute of Russian Academy of Sciences (Moscow, Russia) during 2012-2014 period. It presents the results of research of chemical composition of about 70 small lakes located in the area of tundra and northern taiga of West Siberia (Russia, Yamal-Nenets and Khanty-Mansi Autonomous Districts of the Tyumen region). The investigation includes determination of different parameters of natural water samples: • content of trace elements (Al, Fe, Mn, Cr, Cu, Ni, Zn, Cd, Co, Pb, etc., total more than 60 elements) by emission method with an inductively coupled plasma (ICP-MS) using mass spektrometrometre Element 2 equipment; • content of inorganic and total carbon (TIC and TC) by elemental analysis and the difference between the total and inorganic carbon gives the organic carbon content (TOC); • pH value by potentiometric method; • content of basic ions (Na+, Ca2+, K+, Mg2+, NH4+, Cl-, SO42-, NO3-, PO43-) by ion chromatography. Determination of the chemical composition of samples was conducted in the accredited laboratory according to standard procedures with regular quality control of results. Heavy metals in natural waters can exist in various forms: free (hydrated) ions bound in complexes with organic or inorganic ligands, as well as in the form of suspensions. The form of metal existence has a significant influence on their availability to transport in aquatic organisms. Metal ions associated in stable complexes with organic substances are considered less toxic. From the previous investigations state that the most stable complexes are ligands with organic ions Fe3+, Al3+. The main conclusion of the present research states that if the total content of aluminum, iron and manganese ions (meq/dm3) is equal to or greater than the concentration of dissolved organic carbon (TOC, mg/dm3) in lakes water other heavy metals will

  6. Source of Global Scale Variations in the Midday Vertical Content of Ionospheric Metal Ions

    Science.gov (United States)

    Joiner, J.; Grebowsky, J. M.; Pesnell, W. D.; Aikin, A. C.; Goldberg, Richard A.

    1999-01-01

    An analysis of long baseline NIMBUS 7 SBUV (Solar Backscatter UV Spectrometer) observations of the latitudinal variation of the noontime vertical Mg' content above approx. 70 km have revealed seasonal, solar activity and magnetic activity dependencies in the Mg+ content. The distributions were categorized in terms