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1

HIGH ASPECT RATIO ION EXCHANGE RESIN BED - HYDRAULIC RESULTS FOR SPERICAL RESIN BEADS  

SciTech Connect

A principal role of the DOE Savannah River Site is to safely dispose of a large volume of liquid nuclear waste held in many storage tanks. An in-tank ion exchange unit is being considered for cesium removal to accelerate waste processing. This unit is planned to have a relatively high bed height to diameter ratio (10:1). Complicating the design is the need to cool the ion exchange media; therefore, the ion exchange column will have a central cooling core making the flow path annular. To separate cesium from waste the media being considered is made of resorcinol formaldehyde resin deposited on spherical plastic beads and is a substitute for a previously tested resin made of crystalline silicotitanate. This spherical media not only has an advantage of being mechanically robust, but, unlike its predecessor, it is also reusable, that is, loaded cesium can be removed through elution and regeneration. Resin regeneration leads to more efficient operation and less spent resin waste, but its hydraulic performance in the planned ion exchange column was unknown. Moreover, the recycling process of this spherical resorcinol formaldehyde causes its volume to significantly shrink and swell. To determine the spherical media's hydraulic demand a linearly scaled column was designed and tested. The waste simulant used was prototypic of the wastes' viscosity and density. This paper discusses the hydraulic performance of the media that will be used to assist in the design of a full-scale unit.

Duignan, M; Charles Nash, C; Timothy Punch, T

2007-09-27

2

Composite ion exchange materials  

SciTech Connect

Composite ion exchange materials can be formed by sorbing ion exchange polymers on inert, high surface area substrates. In general, the flux of ions and molecules through these composites, as measured electrochemically, increases as the ratio of the surface area of the substrate increases relative to the volume of the ion exchanger. This suggests that fields and gradients established at the interface between the ion exchanger and substrate are important in determining the transport characteristics of the composites. Here, the authors will focus on composites formed with a cation exchange polymer, Nafion, and two different types of microbeads: polystyrene microspheres and polystyrene coated magnetic microbeads. For the polystyrene microbeads, scanning electron micrographs suggest the beads cluster in a self-similar manner, independent of the bead diameter. Flux of Ru(NH3)63+ through the composites was studied as a function of bead fraction, bead radii, and fixed surface area with mixed bead sizes. Flux was well modeled by surface diffusion along a fractal interface. Magnetic composites were formed with columns of magnetic microbeads normal to the electrode surface. Flux of Ru(NH3)63+ through these composites increased exponentially with bead fraction. For electrolyses, the difference in the molar magnetic susceptibility of the products and reactants, Dcm, tends to be non-zero. For seven redox reactions, the ratio of the flux through the magnetic composites to the flux through a Nafion film increases monotonically with {vert_bar}Dcm{vert_bar}, with enhancements as large as thirty-fold. For reversible species, the electrolysis potential through the magnetic composites is 35 mV positive of that for the Nafion films.

Amarasinghe, S.; Zook, L.; Leddy, J. [Univ. of Iowa, Iowa City, IA (United States)

1994-12-31

3

GE Healthcare Ion exchange  

E-print Network

GE Healthcare Ion exchange columns and media Selection Guide imagination at work #12;Principle. Chromatography media selection Select the ion exchange medium according to the objective of the purification step

Lebendiker, Mario

4

Ion microprobe analysis of oxygen isotope ratios in granulite facies magnetites: diffusive exchange as a guide to cooling history  

NASA Astrophysics Data System (ADS)

Ion microprobe analysis of magnetites from the Adirondack Mountains, NY, yields oxygen isotope ratios with spatial resolution of 2 8 ?m and precision in the range of 1‰ (1 sigma). These analyses represent 11 orders of magnitude reduction in sample size compared to conventional analyses on this material and they are the first report of routinely reproducible precision in the 1 per mil range for analysis of ?18O at this scale. High precision micro-analyses of this sort will permit wide-ranging new applications in stable isotope geochemistry. The analyzed magnetites form nearly spherical grains in a calcite matrix with diopside and monticellite. Textures are characteristic of granulite facies marbles and show no evidence for retrograde recrystallization of magnetite. Magnetites are near to Fe3O4 in composition, and optically and chemically homogeneous. A combination of ion probe plus conventional BrF5 analysis shows that individual grains are homogeneous with ?18O=8.9±1‰ SMOW from the core to near the rim of 0.1 1.2 mm diameter grains. Depth profiling into crystal growth faces of magnetites shows that rims are 9‰ depleted in ?18O. These low ?18O values increase in smooth gradients across the outer 10 ?m of magnetite rims in contact with calcite. These are the sharpest intracrystalline gradients measured to date in geological materials. This discovery is confirmed by bulk analysis of 150 350 ?m diameter magnetites which average 1.2‰ lower in ?18O than coarse magnetites due to low ?18O rims. Conventional analysis of coexisting calcite yields °18O=18.19, suggesting that bulk ?18O (Cc-Mt)=9.3‰ and yielding an apparent equilibration “temperature” of 525° C, over 200° C below the temperature of regional metamorphism. Consideration of experimental diffusion data and grain size distribution for magnetite and calcite suggests two contrasting cooling histories. The data for oxygen in calcite under hydrothermal conditions at high P(H2O) indicates that diffusion is faster in magnetite and modelling of the low ?18O rims on magnetite would suggest that the Adirondacks experienced slow cooling after Grenville metamorphism, followed by a brief period of rapid cooling, possibly related to uplift. Conversely, the data for calcite at low P(H2O) show slower oxygen diffusion than in magnetite. Modelling based on these data is consistent with geochronology that shows slow cooling through the blocking temperature of both minerals, suggesting that the low ?18O rims form by exchange with late, low temperature fluids similar to those that infiltrated the rock to serpentinize monticellite and which infiltrated adjacent anorthosite to form late calcite veinlets. In either case, the ion microprobe results indicate that two distinct events are recorded in the post-metamorphic exchange history of these magnetites. Recognition of these events is only possible through microanalysis and has important implications for geothermometry.

Valley, John W.; Graham, Colin M.

1991-03-01

5

Ion microprobe analysis of oxygen isotope ratios in granulite facies magnetites: diffusive exchange as a guide to cooling history  

Microsoft Academic Search

Ion microprobe analysis of magnetites from the Adirondack Mountains, NY, yields oxygen isotope ratios with spatial resolution of 2 8 mum and precision in the range of 10\\/00 (1 sigma). These analyses represent 11 orders of magnitude reduction in sample size compared to conventional analyses on this material and they are the first report of routinely reproducible precision in the

John W. Valley; Colin M. Graham

1991-01-01

6

Ion microprobe analysis of oxygen isotope ratios in granulite facies magnetites: diffusive exchange as a guide to cooling history  

Microsoft Academic Search

Ion microprobe analysis of magnetites from the Adirondack Mountains, NY, yields oxygen isotope ratios with spatial resolution of 2–8 µm and precision in the range of 1‰ (1 sigma). These analyses represent 11 orders of magnitude reduction in sample size compared to conventional analyses on this material and they are the first report of routinely reproducible precision in the 1

John W. Valley; Colin M. Graham

1991-01-01

7

Ion exchange equilibrium between ion exchange membrane and electrolyte solutions  

Microsoft Academic Search

The ion exchange equilibrium between an ion exchange membrane and solutions of different electrolytes was studied. The matrix of the ion exchange membrane used consists of a vinyl polychloride network reinforced by a polyester screen; with quaternary and tertiary ammonium as functional groups. The data, provided by manufacturer, were completed by the experimental determinations of humidity percentage and ion exchange

Ch. Hannachi; S. Bouguecha; B. Hamrouni; M. Dhahbi

2008-01-01

8

The effects of aspect ratio of inorganic fillers on the structure and property of composite ion-exchange membranes.  

PubMed

A new type of nanocomposite ion-exchange membranes containing sulfonated polyethersulfone (sPES) polymer matrix and sulfonated surface-functionalized mesoporous silica (SS) inorganic fillers was prepared. Various characterizations revealed that the addition of inorganic fillers with different shapes had a significant influence on the membrane structure. The mesoporous inorganic fillers not only created extra pore and water channels, assisting the ionic migration and improving conductivity of the composites, but also provided additional fixed charge groups upon surface modification. This allows the Donnan exclusion to work effectively and thus improve the selectivity of membranes. It was proved that the incorporation of appropriate amount of SS additive could significantly improve the conductivity (up to 20 folds) and permselectivity (about 14%) of the sPES membranes. The performance of these newly developed membranes in desalination by electrodialysis was comparable with that of a commercial membrane (FKE). PMID:21872877

Klaysom, Chalida; Moon, Seung-Hyeon; Ladewig, Bradley P; Lu, G Q Max; Wang, Lianzhou

2011-11-15

9

Pharmaceutical Applications of Ion-Exchange Resins  

NASA Astrophysics Data System (ADS)

The historical uses of ion-exchange resins and a summary of the basic chemical principles involved in the ion-exchange process are discussed. Specific applications of ion-exchange resins are provided. The utility of these agents to stabilize drugs are evaluated. Commonly occurring chemical and physical incompatibilities are reviewed. Ion-exchange resins have found applicability as inactive pharmaceutical constituents, particularly as disintegrants (inactive tablet ingredient whose function is to rapidly disrupt the tablet matrix on contact with gastric fluid). One of the more elegant approaches to improving palatability of ionizable drugs is the use of ion-exchange resins as taste-masking agents. The selection, optimization of drug:resin ratio and particle size, together with a review of scaleup of typical manufacturing processes for taste-masked products are provided. Ion-exchange resins have been extensively utilized in oral sustained-release products. The selection, optimization of drug:resin ratio and particle size, together with a summary of commonly occurring commercial sustained-release products are discussed. Ion-exchange resins have also been used in topical products for local application to the skin, including those where drug flux is controlled by a differential electrical current (ionotophoretic delivery). General applicability of ion-exchange resins, including ophthalmic delivery, nasal delivery, use as drugs in their own right (e.g., colestyramine, formerly referred to as cholestyramine), as well as measuring gastrointestinal transit times, are discussed. Finally, pharmaceutical monographs for ion-exchange resins are reviewed.

Elder, David P.

2005-04-01

10

Biological Ion Exchanger Resins  

PubMed Central

Biological selectivity is shown to vary with medium osmotic strength and temperature. Selectivity reversals occur at 4°C and at an external osmolality of 0.800 indicating that intracellular hydration and endosolvent (intracellular water) structure are important determinants in selectivity. Magnetic resonance measurements of line width by steady-state nuclear magnetic resonance (NMR) indicate a difference in the intracellular water signal of 16 Hz between the K form and Na form of Escherichia coli, providing additional evidence that changes in the ionic composition of cells are accompanied by changes in endosolvent structure. The changes were found to be consistent with the thermodynamic and magnetic resonance properties of aqueous electrolyte solutions. Calculation of the dependence of ion-pairing forces on medium dielectric reinforces the role of endosolvent structure in determining ion exchange selectivity. PMID:4943653

Damadian, Raymond; Goldsmith, Michael; Zaner, K. S.

1971-01-01

11

Ion exchange technology assessment report  

SciTech Connect

In the execution of its charter, the SRS Ion Exchange Technology Assessment Team has determined that ion exchange (IX) technology has evolved to the point where it should now be considered as a viable alternative to the SRS reference ITP/LW/PH process. The ion exchange media available today offer the ability to design ion exchange processing systems tailored to the unique physical and chemical properties of SRS soluble HLW's. The technical assessment of IX technology and its applicability to the processing of SRS soluble HLW has demonstrated that IX is unquestionably a viable technology. A task team was chartered to evaluate the technology of ion exchange and its potential for replacing the present In-Tank Precipitation and proposed Late Wash processes to remove Cs, Sr, and Pu from soluble salt solutions at the Savannah River Site. This report documents the ion exchange technology assessment and conclusions of the task team.

Duhn, E.F.

1992-01-01

12

Ion exchange technology assessment report  

SciTech Connect

In the execution of its charter, the SRS Ion Exchange Technology Assessment Team has determined that ion exchange (IX) technology has evolved to the point where it should now be considered as a viable alternative to the SRS reference ITP/LW/PH process. The ion exchange media available today offer the ability to design ion exchange processing systems tailored to the unique physical and chemical properties of SRS soluble HLW`s. The technical assessment of IX technology and its applicability to the processing of SRS soluble HLW has demonstrated that IX is unquestionably a viable technology. A task team was chartered to evaluate the technology of ion exchange and its potential for replacing the present In-Tank Precipitation and proposed Late Wash processes to remove Cs, Sr, and Pu from soluble salt solutions at the Savannah River Site. This report documents the ion exchange technology assessment and conclusions of the task team.

Duhn, E.F.

1992-12-31

13

Ion-exchange hollow fibers  

NASA Technical Reports Server (NTRS)

An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, cross-linked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Klein, Elias (Inventor)

1980-01-01

14

Ion-exchange hollow fibers  

NASA Technical Reports Server (NTRS)

An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, cross-linked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Klein, Elias (Inventor)

1977-01-01

15

Ion-exchange hollow fibers  

NASA Technical Reports Server (NTRS)

An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, crosslinked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

Rembaum, A.; Yen, S. P. S.; Klein, E. (inventors)

1976-01-01

16

Ion exchange - Simulation and experiment  

NASA Technical Reports Server (NTRS)

A FORTRAN program for simulating multicomponent adsorption by ion-exchange resins was adapted for use as both an ASPEN-callable module and as a free-standing simulator of the ion-exchange bed. Four polystyrene-divinylbenzene sulfonic acid resins have been characterized for three principal ions. It is concluded that a chelating resin appears appropriate as a heavy-metal trap. The same ASPEN-callable module is used to model this resin when Wilson parameters can be obtained.

Herrmann, Cal C.; Finn, John E.

1991-01-01

17

Electrically switched cesium ion exchange  

SciTech Connect

Electrically Switched Ion Exchange (ESIX) is a separation technology being developed as an alternative to conventional ion exchange for removing radionuclides from high-level waste. The ESIX technology, which combines ion exchange and electrochemistry, is geared toward producing electroactive films that are highly selective, regenerable, and long lasting. During the process, ion uptake and elution are controlled directly by modulating the potential of an ion exchange film that has been electrochemically deposited onto a high surface area electrode. This method adds little sodium to the waste stream and minimizes the secondary wastes associated with traditional ion exchange techniques. Development of the ESIX process is well underway for cesium removal using ferrocyanides as the electroactive films. Films having selectivity for perrhenate (a pertechnetate surrogate) over nitrate also have been deposited and tested. A case study for the KE Basin on the Hanford Site was conducted based on the results of the development testing. Engineering design baseline parameters for film deposition, film regeneration, cesium loading, and cesium elution were used for developing a conceptual system. Order of magnitude cost estimates were developed to compare with conventional ion exchange. This case study demonstrated that KE Basin wastewater could be processed continuously with minimal secondary waste and reduced associated disposal costs, as well as lower capital and labor expenditures.

Lilga, M.A.; Orth, R.J.; Sukamto, J.P.H. [Pacific Northwest National Lab., Richland, WA (United States); Schwartz, D.T.; Haight, S.M. [Univ. of Washington, Seattle, WA (United States); Genders, J.D. [Electrosynthesis Co., Inc. (United States)

1997-04-01

18

Cesium-specific phenolic ion exchange resin  

DOEpatents

A phenolic, cesium-specific, cation exchange resin is prepared by neutralizing resorcinol with potassium hydroxide, condensing/polymerizing the resulting intermediate with formaldehyde, heat-curing the resulting polymer to effect cross-linking and grinding it to desired particle size for use. This resin will selectively and efficiently adsorb cesium ions in the presence of a high concentration of sodium ions with a low carbon to cesium ratio. 2 figs.

Bibler, J.P.; Wallace, R.M.

1995-08-15

19

Cesium-specific phenolic ion exchange resin  

DOEpatents

A phenolic, cesium-specific, cation exchange resin is prepared by neutralizing resorcinol with potassium hydroxide, condensing/polymerizing the resulting intermediate with formaldehyde, heat-curing the resulting polymer to effect cross-linking and grinding it to desired particle size for use. This resin will selectively and efficiently adsorb cesium ions in the presence of a high concentration of sodium ions with a low carbon to cesium ratio.

Bibler, Jane P. (Aiken, SC); Wallace, Richard M. (Aiken, SC)

1995-01-01

20

A Colorful Ion Exchange Experiment  

NASA Astrophysics Data System (ADS)

A colorful ion-exchange experiment is described. The use of a resin with an adsorbed acid-base indicator allows students to follow the progress of the ion-exchange front along the column. In parallel, students can follow the ion-exchange breakthrough curve using a continuous conductometric cell at the column outlet. In the present example, K+ (KCl) exchanges with H+ (HCl) in a strong cationic resin (Amberlite IR 120). The adsorbed indicator is methyl violet. Sorption equilibrium is favorable to the K+ ions. Monovalent ions, used in this experiment, have the disadvantage of usually being colorless (except perhaps permanganate, but this is an extremely strong oxidant which attacks the resin). On the other hand, many divalent ions are colorful but the shape of the concentration front is hard to explain qualitatively as well as quantitatively. That is because the shape of the front depends on the total ionic concentration. However, color can be introduced in a monovalent ion-exchange system by adding an appropriate acid-base indicator to the resin. The text describes this experiment qualitatively. A simplified quantitative description, using the solute movement theory, can be found online.

Mendes, Adélio

1999-11-01

21

Electrically Switched Cesium Ion Exchange  

SciTech Connect

This report discusses the results of work to develop Electrically Switched Ion Exchange (ESIX) for separations of ions from waste streams relevant to DOE site clean-up. ESIX combines ion exchange and electrochemistry to provide a selective, reversible method for radionuclide separation that lowers costs and minimizes secondary waste generation typically associated with conventional ion exchange. In the ESIX process, an electroactive ion exchange film is deposited onto. a high surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. As a result, the production of secondary waste is minimized, since the large volumes of solution associated with elution, wash, and regeneration cycles typical of standard ion exchange are not needed for the ESIX process. The document is presented in two parts: Part I, the Summary Report, discusses the objectives of the project, describes the ESIX concept and the approach taken, and summarizes the major results; Part II, the Technology Description, provides a technical description of the experimental procedures and in-depth discussions on modeling, case studies, and cost comparisons between ESIX and currently used technologies.

JPH Sukamto; ML Lilga; RK Orth

1998-10-23

22

Phosphonic acid based ion exchange resins  

DOEpatents

An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 10 figs.

Horwitz, E.P.; Alexandratos, S.D.; Gatrone, R.C.; Chiarizia, R.

1996-07-23

23

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange-resin are also disclosed.

Trochimcznk, Andrzej W. (Knoxville, TN); Gatrone, Ralph C. (Plymouth, PA); Alexandratos, Spiro (Knoxville, TN); Horwitz, E. Philip (Naperville, IL)

1998-01-27

24

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

An ion exchange resin is disclosed that is comprised of an insoluble copolymer onto which are grafted pendent groups that provide 1.0 to about 10 mmol/g dry weight phosphorous. The pendent groups have the formula ##STR1## wherein R is hydrogen, a cation or mixtures thereof; and R.sup.1 is hydrogen or an C.sub.1 -C.sub.2 alkyl group. The resin also contains zero to about 5 mmol/g dry weight of pendent aromatic sulfonate groups. Processes for making and using an ion exchange resin are also disclosed.

Trochimcznk, Andrzej W. (Knoxbille, TN); Gatrone, Ralph C. (Plymouth, PA); Alexandratos, Spiro (Knoxville, TN); Horwitz, E. Philip (Naperville, IL)

1997-01-01

25

Disposal of bead ion exchange resin wastes  

SciTech Connect

Bead ion exchange resin wastes are disposed of by a process which involves spray-drying a bead ion exchange resin waste in order to remove substantially all of the water present in such waste, including the water on the surface of the ion exchange resin beads and the water inside the ion exchange resin beads. The resulting dried ion exchange resin beads can then be solidified in a suitable solid matrix-forming material, such as a polymer, which solidifies to contain the dried ion exchange resin beads in a solid monolith suitable for disposal by burial or other conventional means.

Gay, R.L.; Granthan, L.F.

1985-12-17

26

Ion Exchange and Liquid Column Chromatography.  

ERIC Educational Resources Information Center

Emphasizes recent advances in principles and methodology in ion exchange and chromatography. Two tables list representative examples for inorganic ions and organic compounds. Cites 544 references. (CS)

Walton, Harold F.

1980-01-01

27

Synthesis and ion-exchange properties of lanthanum tungstate, a new inorganic ion exchanger  

SciTech Connect

Amorphous samples of a new inorganic ion exchanger, lanthanum tungstate, have been prepared under varying conditions. The material prepared by mixing 0.05 M lanthanum nitrate and 0.05 M sodium tungstate in a ratio of 1:2 was studied in detail for its ion-exchange capacity, chemical stability, ir, thermogravimetry, and K/sub d/ values. Its columns have been used for the separation of C/sup 2 +/ from Pd/sup 2 +/, Mn/sup 2 +/, and Cu/sup 2 +/, and Ni/sup 2 +/ from Pd/sup 2 +/. 3 figures, 4 tables.

Husain, S.W.; Rasheedzad, S.; Manzoori, J.L.; Jabbari, Y.

1982-01-01

28

Pharmaceutical Applications of Ion-Exchange Resins  

ERIC Educational Resources Information Center

The historical uses of ion-exchanged resins and a summary of the basic chemical principles involved in the ion-exchanged process are discussed. Specific applications of ion-exchange are provided that include drug stabilization, pharmaceutical excipients, taste-masking agents, oral sustained-release products, topical products for local application…

Elder, David

2005-01-01

29

Ion exchange purification of scandium  

DOEpatents

An improvement in purification of scandium through ion exchange chromatography is disclosed in which the oxidation potential of the eluting solution is altered by the addition of potassium chlorate or ammonium chloride so that removal of contaminants is encouraged. The temperature, pH and concentration of the eluent HEDTA are controlled in order to maintain the scandium in the column while minimizing dilution of the scandium band. Recovery of scandium is improved by pumping dilute scandium over the column prior to stripping the scandium and precipitation. This eliminates the HEDTA ion and other monovalent cations contaminating the scandium band. This method maximizes recovery of scandium while maintaining purity.

Herchenroeder, Laurie A. (Noblesville, IN); Burkholder, Harvey R. (Ames, IA)

1990-10-23

30

Copper diffusion in ion-exchanged soda-lime glass  

NASA Astrophysics Data System (ADS)

Cu-alkali ion exchange in silicate glasses gives rise to a peculiar copper distribution, with the presence of both the Cu2+ and Cu+ oxidation states. Grazing incidence X-ray absorption near-edge structure spectroscopy and secondary ion mass spectrometry were performed on different ion-exchanged samples. The results show that the Cu2+/Cu+ ratio is strongly depth-dependent. The relative presence of the two species throughout the exchanged region turns out to be governed by their different diffusion regimes, while the chemistry of the red-ox process is shown to play a minor role. A phenomenological model is proposed to describe the diffusion process.

Gonella, F.; Quaranta, A.; Padovani, S.; Sada, C.; D'Acapito, F.; Maurizio, C.; Battaglin, G.; Cattaruzza, E.

2005-10-01

31

XAFS Studies of Silver Environments in Ion-Exchanged Glasses  

SciTech Connect

The X-ray absorption fine structure (XAFS) technique was used to analyze the structural geometry of Ag atoms introduced into soda-lime silicate glass and soda aluminosilicate glass by ion-exchange methods. The results show that Ag+ ions in aluminosilicate glass are coordinated by about two oxygens and the nearest-neighbor Ag-O distance increases when the Ag+-for-Na+ ion-exchange ratio is larger than 0.47. When the exchange ratio is low, the introduced Ag+ ions are stabilized at the non-bridge oxygen (NBO) site with a Ag-O distance of 2.20 A, and the Na+ ions in the AlO4 site are exchanged by Ag+ ions after full replacement of the NBO sites with a Ag-O distance of 2.28 A. The disorder of Ag-O coordination increases with increasing ion-exchange ratio in aluminosilicate glass where Ag+ ions are coordinated by NBO and bridge oxygen (BO)

Yang, X. C. [College of Materials Science and Engineering, Tongji University, Shanghai 200092 (China); Dubiel, M. [Department of Physics, Martin Luther University of Halle, D-06108 Halle (Germany)

2007-02-02

32

DUAL-TEMPERATURE ION EXCHANGE FRACTIONATION  

Microsoft Academic Search

This paper reviews the results obtained by studying the dual-temperature ion-exchange fractionation (DTIXF) technique. The DTIXF is based on the use of different affinity at different temperatures of ion exchangers towards ions to be separated. This technique allows to design absolutely reagentless and, as a result, wasteless fractionation technology. The review considers the temperature dependencies of selectivity of commercially available

Dmitri Muraviev; Joan Noguerol; Manuel Valiente

1999-01-01

33

Ion-exchange chromatographic protein refolding  

Microsoft Academic Search

The application of ion-exchange (IEX) chromatography to protein refolding (IExR) has been successfully proven, as supported by various studies using different model proteins, ion-exchange media and flow configurations. Ion-exchange refolding offers a relatively high degree of process intensification, represented by the possibility of performing protein refolding, product purification and product concentration, in one unit operation. Besides its high degree of

Esteban J. Freydell; Luuk van der Wielen; Michel Eppink; Marcel Ottens

2010-01-01

34

Solidification of ion exchange resin wastes  

SciTech Connect

Solidification media investigated included portland type I, portland type III and high alumina cements, a proprietary gypsum-based polymer modified cement, and a vinyl ester-styrene thermosetting plastic. Samples formulated with hydraulic cement were analyzed to investigate the effects of resin type, resin loading, waste-to-cement ratio, and water-to-cement ratio. The solidification of cation resin wastes with portland cement was characterized by excessive swelling and cracking of waste forms, both after curing and during immersion testing. Mixed bed resin waste formulations were limited by their cation component. Additives to improve the mechanical properties of portland cement-ion exchange resin waste forms were evaluated. High alumina cement formulations dislayed a resistance to deterioration of mechanical integrity during immersion testing, thus providing a significant advantage over portland cements for the solidification of resin wastes. Properties of cement-ion exchange resin waste forms were examined. An experiment was conducted to study the leachability of /sup 137/Cs, /sup 85/Sr, and /sup 60/Co from resins modified in portland type III and high alumina cements. The cumulative /sup 137/Cs fraction release was at least an order of magnitude greater than that of either /sup 85/Sr or /sup 60/Co. Release rates of /sup 137/Cs in high alumina cement were greater than those in portland III cement by a factor of two.Compressive strength and leach testing were conducted for resin wastes solidified with polymer-modified gypsum based cement. /sup 137/Cs, /sup 85/Sr, and /sup 60/Co fraction releases were about one, two and three orders of magnitude higher, respectively, than in equivalent portland type III cement formulations. As much as 28.6 wt % dry ion exchange resin was successfully solidified using vinyl ester-styrene compared with a maximum of 25 wt % in both portland and gypsum-based cement.

Not Available

1982-08-01

35

Using Ion Exchange Chromatography to Separate and Quantify Complex Ions  

ERIC Educational Resources Information Center

Ion exchange chromatography is an important technique in the separation of charged species, particularly in biological, inorganic, and environmental samples. In this experiment, students are supplied with a mixture of two substitution-inert complex ions. They separate the complexes by ion exchange chromatography using a "flash"…

Johnson, Brian J.

2014-01-01

36

Determination of ¹³?Cs and ¹³?Cs/¹³?Cs atomic ratio in environmental samples by combining ammonium molybdophosphate (AMP)-selective Cs adsorption and ion-exchange chromatographic separation to triple-quadrupole inductively coupled plasma-mass spectrometry.  

PubMed

Since the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, the activity ratio of (134)Cs/(137)Cs has been widely used as a tracer for contamination source identification. However, because of the short half-life of (134)Cs (2.06 y), this tracer will become unavailable in the near future. This article presents an analytical method for the determination of the long-lived (135)Cs (t(2/1) = 2 × 10(6) y) and the atomic ratio of (135)Cs/(137)Cs, as a promising geochemical tracer, in environmental samples. The analytical method involves ammonium molybdophosphate (AMP)-selective adsorption of Cs and subsequent two-stage ion-exchange chromatographic separation, followed by detection of isolated radiocesium isotopes via triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS). The AMP-selective adsorption of Cs and the chromatographic separation system showed high decontamination factors (10(4)-10(5)) for interfering elements, such as Ba, Mo, Sb, and Sn. Using ICP-MS/MS, only selected ions enter the collision/reaction cell to react with N2O, reducing the isobaric interferences ((135)Ba(+) and (137)Ba(+)) and polyatomic interferences ((95) Mo(40)Ar(+), (97) Mo(40)Ar(+), (119)Sn(16)O(+), and (121)Sb(16)O(+)) produced by sample matrix ions. The high abundance sensitivity (10(-9) for the (135)Cs/(133)Cs ratio) provided by ICP-MS/MS allowed reliable analysis of (135)Cs and (137)Cs isotopes with the lowest detection limits ever reported by mass counting methods (0.01 pg mL(-1) and 0.006 pg mL(-1), respectively). The developed analytical method was successfully applied to the determination of (135)Cs and (137)Cs isotopes in environmental samples (soil, litter, and lichen) collected after the FDNPP accident for contamination source identification. PMID:24931104

Zheng, Jian; Bu, Wenting; Tagami, Keiko; Shikamori, Yasuyuki; Nakano, Kazumi; Uchida, Shigeo; Ishii, Nobuyoshi

2014-07-15

37

Ion Exchange and Adsorption of Inorganic Contaminants  

EPA Science Inventory

In the first part of the chapter, the fundamentals of ion exchange and adsorption processes are explained, with the goal of demonstrating how these principles influence process design for inorganic contaminant removal. In the second part, ion exchange and adsorption processes th...

38

Nonaqueous ion-exchange chromatography and electrophoresis  

Microsoft Academic Search

Compiling ion-exchange chromatographic data, which has been allowed by recent developments in chromatographic techniques, indicates that solvation plays important roles in determining selectivity. Ion-exchange chromatography in nonaqueous solvents is not a novel idea, but is expected to give insights into roles of solvation in separation mechanisms, because changing solvents is the simplest way to study solvation effects. Thus, nonaqueous media

Tetsuo Okada

1998-01-01

39

Titania bound sodium titanate ion exchanger  

DOEpatents

This invention is method for preparing a titania bound ion exchange composition comprising admixing crystalline sodium titanate and a hydrolyzable titanium compound and, thereafter drying the titania bound crystalline sodium titanate and subjecting the dried titania bound ion exchange composition to optional compaction and calcination steps to improve the physical strength of the titania bound composition.

DeFilippi, Irene C. G. (Palatine, IL); Yates, Stephen Frederic (Rolling Meadows, IL); Shen, Jian-Kun (Lake Zurich, IL); Gaita, Romulus (Morton Grove, IL); Sedath, Robert Henry (Bensenville, IL); Seminara, Gary Joseph (Chicago, IL); Straszewski, Michael Peter (Novi, MI); Anderson, David Joseph (Oak Lawn, IL)

1999-03-23

40

Ion Exchange of Zeolite Na-Pc with Pb2+, Zn2+, and Ni2+ Ions  

Microsoft Academic Search

This paper examines the ion-exchange properties of synthetic zeolite Na-P0, which was pro- duced from perlite-waste fines and has a SiO2:A1203 ratio of 4.45:1 and a cation-exchange capacity (CEC) of 3.95 meq g ~. Although equilibrium is attained rapidly for all three metals, exchange is incomplete, with At(max) (maximum equilibrium fraction of the metal in the zeolite) being 0.95 for

Aggeliki Moirou; GEORGIOS E. CHRISTIDIS; IOANNIS PASPALIARIS

2000-01-01

41

COMPLEXATION IN ION EXCHANGER PHASE. PROPERTIES AND APPLICATION OF ION EXCHANGER COMPLEXES  

Microsoft Academic Search

This paper reviews the properties of complex forming ion exchangers (CFIE) and those of the ion exchanger complexes (IEC) with transition metal ions. It is mainly dedicated to the development of a novel approach in characterizing IEC which is based on the consideration of CFIE as three-dimensional polymeric ligands. The approach is illustrated by the results obtained by studying the

Valentina D. Kopylova

1998-01-01

42

REAGENT-FREE ION-EXCHANGE SEPARATIONS  

Microsoft Academic Search

This paper reviews the development of reagent-free (and therefore ecologically clean) ion-exchange separation techniques. These methods are based on the shift of the ion exchanger selectivity induced by the modulation of some physico-chemical parameters of the system such as temperature, solution concentration, pH, etc. This approach avoids the use of auxiliary reagents and additional operations such as the regeneration of

Vladimir I. Gorshkov; Vladimir A. Ivanov

1999-01-01

43

Porous Ceramic Spheres from Ion Exchange Resin  

NASA Technical Reports Server (NTRS)

A commercial cation ion exchange resin, cross-linked polystyrene, has been successfully used as a template to fabricate 20 to 50 micron porous ceramic spheres. Ion exchange resins have dual template capabilities. Pore architecture of the ceramic spheres can be altered by changing the template pattern. Templating can be achieved by utilizing the internal porous structure or the external surface of the resin beads. Synthesis methods and chemical/physical characteristics of the ceramic spheres will be reported.

Dynys, Fred

2005-01-01

44

Gold recovery with ion exchange used resins  

Microsoft Academic Search

In this paper one strong acidic, one strong basic and one weak basic ion-exchange resins, considered as exhausted in an industrial demineralizing plant, are screened for gold recovery from cyanide solutions. Based on the observed ability for the recovery and on the ease of regeneration, the weak base anion exchanger Purolite A-100 is selected. This spent resin is stable until

Carmen P. Gomes; Manuel F. Almeida; José M. Loureiro

2001-01-01

45

Ion Exchange Resins Transforming Drug Delivery Systems.  

PubMed

Ion-exchange resins are light, porous, three-dimensional high molecular weight cross -linked matrix of hydrocarbon chains carrying positively or negatively charged sites that can attract an ion of opposite charge from the surrounding medium. There is stoichiometric exchange of mobile ions between the solid and the solution called as Ion-exchange which does not lead to any radical change in the properties and structure of the solid. Depending upon the type of Ion-exchanged it can be either Cation-exchange or Anion-exchange. They are prepared in the form of granules, beads or sheets. As drug delivery systems they have received considerable attention after the 1950s due to their inertness, freedom from side effects, high drug loading capacity, ease of sterilization and the fact that their structure can be easily altered to achieve the desired drug release characteristics. Their use is revolutionizing all traditional delivery systems namely- oral, nasal, ophthalmic and parenteral. Ion- exchange resins have been used for the development of novel drug delivery systems (NDDSs), to modify the characteristics of the dosage form and various other biomedical applications. The present article deals with the varied applications of ion-exchange resins for taste making, as resinates (simple and microencapsulated or coated), Pennkinetic systems, in selective recovery of pharmaceuticals, in pH and ionic strength responsive systems, in gastro-retentive systems, in hollow fiber systems, as sigmoidal release systems, as site specific delivery systems and as inotophoretically assisted transdermal drug delivery systems. They also have an immense importance when used as disintegrants / superdisintegrants in formulation of orodispersible tablets, powder processing aids and in the dissolution and stabilization of drugs. PMID:20158479

Gupta, Shweta; Parul; Sahoo, P K

2010-02-17

46

ION EXCHANGE SOFTENING: EFFECTS ON METAL CONCENTRATIONS  

EPA Science Inventory

A corrosion control pipe loop study to evaluate the effect of ion exchange water softening on metal leaching from household plumbing materials was conducted on two different water qualities having different pH's and hardness levels. The results showed that removing hardness ions ...

47

Regeneration of spent powdered activated carbon saturated with inorganic ions by cavitation united with ion exchange method.  

PubMed

Using ion exchange resin as transfer media, regenerate powdered activated carbon (PAC) adsorbed inorganic ions by cavitation to enhance the transfer; we studied how the regeneration time and the mass ratio of resin and PAC influence the regeneration rate respectively through re-adsorption. The result showed that the effective regeneration of PAC saturated with inorganic ions was above 90% using ion exchange resin as media and transfer carrier, the quantity of PAC did not reduced but activated in the process. PMID:25084579

Li, Gang; Gao, Hong; Li, Yansheng; Yang, Huixin

2011-06-01

48

Nano/microstructured ion exchange resins and their applications.  

PubMed

Ion exchange resins, due to their specific nano/microstructures and applications, have attracted great attention in the past decades. This paper reviews the recent advances and applications of nano/microstructured ion exchange resins, with an introduction to the preparation and property of different ion exchange resins. The applications of different ion exchange resins in catalysts, medicine, metallurgical regeneration, metals, and chemicals removal are summarized and discussed. The perspectives for the future developments of ion exchange resins are also proposed. PMID:24749456

Yu, Bing; Cong, Hailin; Yuan, Hua; Liu, Xuesong; Jiao, Mingming; Wang, Dong

2014-02-01

49

Ion Exchange Resins Transforming Drug Delivery Systems.  

PubMed

Ion-exchange resins are light, porous, three-dimensional high molecular weight cross -linked matrix of hydrocarbon chains carrying positively or negatively charged sites that can attract an ion of opposite charge from the surrounding medium. There is stoichiometric exchange of mobile ions between the solid and the solution called as Ion-exchange which does not lead to any radical change in the properties and structure of the solid. Depending upon the type of Ionexchanged it can be either Cation-exchange or Anion-exchange. They are prepared in the form of granules, beads or sheets. As drug delivery systems they have received considerable attention after the 1950s due to their inertness, freedom from side effects, high drug loading capacity, ease of sterilization and the fact that their structure can be easily altered to achieve the desired drug release characteristics. Their use is revolutionizing all traditional delivery systems namely- oral, nasal, ophthalmic and parenteral. Ion- exchange resins have been used for the development of novel drug delivery systems (NDDSs), to modify the characteristics of the dosage form and various other biomedical applications. The present article deals with the varied applications of ion-exchange resins for taste making, as resinates (simple and microencapsulated or coated), Pennkinetic systems, in selective recovery of pharmaceuticals, in pH and ionic strength responsive systems, in gastro-retentive systems, in hollow fiber systems, as sigmoidal release systems, as site specific delivery systems and as inotophoretically assisted transdermal drug delivery systems. They also have an immense importance when used as disintegrants/ superdisintegrants in formulation of orodispersible tablets, powder processing aids and in the dissolution and stabilization of drugs. PMID:20497105

Gupta, Shweta; Benien, Parul; Sahoo, P K

2010-05-24

50

Metal ion separations using electrically switched ion exchange  

Microsoft Academic Search

An electrochemical method for metal ion separations, called electrically switched ion exchange (ESIX), is described in this paper. In this method, direct oxidation and reduction of an electroactive film attached to an electrode surface is used to load and unload the film with alkali metal cations. The electroactive films under investigation are nickel hexacyanoferrates, which are deposited on the surface

M. A. Lilga; R. J. Orth; J. P. H. Sukamto; S. M. Haight; D. T. Schwartz

1997-01-01

51

Modeling of Crystalline Silicotitanate Ion Exchange Columns  

SciTech Connect

Non-elutable ion exchange is being considered as a potential replacement for the In-Tank Precipitation process for removing cesium from Savannah River Site (SRS) radioactive waste. Crystalline silicotitanate (CST) particles are the reference ion exchange medium for the process. A major factor in the construction cost of this process is the size of the ion exchange column required to meet product specifications for decontaminated waste. To validate SRS column sizing calculations, SRS subcontracted two reknowned experts in this field to perform similar calculations: Professor R. G. Anthony, Department of Chemical Engineering, Texas A&038;M University, and Professor S. W. Wang, Department of Chemical Engineering, Purdue University. The appendices of this document contain reports from the two subcontractors. Definition of the design problem came through several meetings and conference calls between the participants and SRS personnel over the past few months. This document summarizes the problem definition and results from the two reports.

Walker, D.D.

1999-03-09

52

Graphene/Ionic liquid composite films and ion exchange.  

PubMed

Wettability of graphene is adjusted by the formation of various ionic surfaces combining ionic liquid (IL) self-assembly with ion exchange. The functionalized ILs were designed and synthesized with the goal of obtaining adjustable wettability. The wettability of the graphene surface bearing various anions was measured systematically. The effect of solvent systems on ion exchange ratios on the graphene surface has also been investigated. Meanwhile, the mechanical properties of the graphene/IL composite films were investigated on a nanometer scale. The elasticity and adhesion behavior of the thin film was determined with respected to the indentation deformation by colloid probe nanoindentation method. The results indicate that anions played an important role in determining graphene/IL composite film properties. In addition, surface wetting and mechanics can be quantitatively determined according to the counter-anions on the surface. This study might suggest an alternate way for quantity detection of surface ions by surface force. PMID:24970602

Mo, Yufei; Wan, Yunfang; Chau, Alicia; Huang, Fuchuan

2014-01-01

53

Graphene/Ionic Liquid Composite Films and Ion Exchange  

NASA Astrophysics Data System (ADS)

Wettability of graphene is adjusted by the formation of various ionic surfaces combining ionic liquid (IL) self-assembly with ion exchange. The functionalized ILs were designed and synthesized with the goal of obtaining adjustable wettability. The wettability of the graphene surface bearing various anions was measured systematically. The effect of solvent systems on ion exchange ratios on the graphene surface has also been investigated. Meanwhile, the mechanical properties of the graphene/IL composite films were investigated on a nanometer scale. The elasticity and adhesion behavior of the thin film was determined with respected to the indentation deformation by colloid probe nanoindentation method. The results indicate that anions played an important role in determining graphene/IL composite film properties. In addition, surface wetting and mechanics can be quantitatively determined according to the counter-anions on the surface. This study might suggest an alternate way for quantity detection of surface ions by surface force.

Mo, Yufei; Wan, Yunfang; Chau, Alicia; Huang, Fuchuan

2014-06-01

54

Waste treatment by selective mineral ion exchanger  

Microsoft Academic Search

STMI, subsidiary company of the AREVA Group with over 40 years in the D and D business, has been continuously innovating and developing new decontamination techniques, with the objectives of achieving more efficient decontaminations on a growing spectrum of media. In the field of liquid waste treatment, STMI manufactures uses and commercialises selective inorganic ion exchangers (RAN). These are hydrated

Polito; Aurelie

2007-01-01

55

Adsorption and selection of rhizobia with ion-exchange papers  

Microsoft Academic Search

Ion exchange papers were used to study the adsorption of 32P-labelled rhizobia on defined surfaces. Two strains of Rhizobium japonicum and one each of R. leguminosarum and R. lupini were compared with Escherichia coli and Bacillus subtilis. The ratio of adsorption to strong and to weak acid papers\\/strong and weak basic papers was consistantly higher for all rhizobial strains compared

D. Werner; J. Wilcockson; E. Zimmermann

1975-01-01

56

Thermodynamics of Binary and Ternary Ion Exchange in Zeolites: The Exchange of Sodium, Ammonium and Potassium Ions in Mordenite  

Microsoft Academic Search

In many ion exchanges that involve zeolites, more than two types of exchanging ions are involved. Most work to date has been concerned with equilibria involving two different types of ion only. In this paper, a recently devised thermodynamic treatment for exchange equilibria involving three ions is tested experimentally. In section 1 the most important aspects of this thermodynamic model

P. Fletcher; K. R. Franklin; R. P. Townsend

1984-01-01

57

Ion exchange in a zeolite-molten chloride system  

SciTech Connect

Electrometallurgical treatment of spent nuclear fuel results in a secondary waste stream of radioactive fission products dissolved in chloride salt. Disposal plans include a waste form that can incorporate chloride forms featuring one or more zeolites consolidated with sintered glass. A candidate method for incorporating fission products in the zeolites is passing the contaminated salt over a zeolite column for ion exchange. To date, the molten chloride ion-exchange properties of four zeolites have been investigated for this process: zeolite A, IE95{reg_sign}, clinoptilolite, and mordenite. Of these, zeolite A has been the most promising. Treating zeolite 4A, the sodium form of zeolite A , with the solvent salt for the waste stream-lithium-potassium chloride of eutectic melting composition, is expected to provide a material with favorable ion-exchange properties for the treatment of the waste salt. The authors constructed a pilot-plant system for the ion-exchange column. Initial results indicate that there is a direct relationship between the two operating variable of interest, temperature, and initial sodium concentration. Also, the mass ratio has been about 3--5 to bring the sodium concentration of the effluent below 1 mol%.

Woodman, R.H.; Pereira, C. [Argonne National Lab., IL (United States). Chemical Technology Div.

1997-07-01

58

Electrically switched cesium ion exchange. FY 1997 annual report  

SciTech Connect

This paper describes the Electrically Switched Ion Exchange (ESIX) separation technology being developed as an alternative to ion exchange for removing radionuclides from high-level waste. Progress in FY 1997 for specific applications of ESIX is also outlined. The ESIX technology, which combines ion exchange and electrochemistry, is geared toward producing electroactive films that are highly selective, regenerable, and long lasting. During the process, ion uptake and elution can be controlled directly by modulating the potential of an ion exchange film that has been electrochemically deposited onto a high surface area electrode. This method adds little sodium to the waste stream and minimizes the secondary wastes associated with traditional ion exchange techniques. Development of the ESIX process is well underway for cesium removal using ferrocyanides as the electroactive films. Films having selectivity for perrhenate (a pertechnetate surrogate) over nitrate also have been deposited and tested. Based on the ferrocyanide film capacity, stability, rate of uptake, and selectivity shown during performance testing, it appears possible to retain a consistent rate of removal and elute cesium into the same elution solution over several load/unload cycles. In batch experiments, metal hexacyanoferrate films showed high selectivities for cesium in concentrated sodium solutions. Cesium uptake was unaffected by Na/Cs molar ratios of up to 2 x 10{sup 4} , and reached equilibrium within 18 hours. During engineering design tests using 60 pores per inch, high surface area nickel electrodes, nickel ferrocyanide films displayed continued durability. losing less than 20% of their capacity after 1500 load/unload cycles. Bench-scale flow system studies showed no change in capacity or performance of the ESIX films at a flow rate up to 13 BV/h, the maximum flow rate tested, and breakthrough curves further supported once-through waste processing. 9 refs., 24 figs.

Lilga, M.A.; Orth, R.J.; Sukamto, J.P.H. [and others

1997-09-01

59

SPEEDUP{trademark} ion exchange column model  

SciTech Connect

A transient model to describe the process of loading a solute onto the granular fixed bed in an ion exchange (IX) column has been developed using the SpeedUp{trademark} software package. SpeedUp offers the advantage of smooth integration into other existing SpeedUp flowsheet models. The mathematical algorithm of a porous particle diffusion model was adopted to account for convection, axial dispersion, film mass transfer, and pore diffusion. The method of orthogonal collocation on finite elements was employed to solve the governing transport equations. The model allows the use of a non-linear Langmuir isotherm based on an effective binary ionic exchange process. The SpeedUp column model was tested by comparing to the analytical solutions of three transport problems from the ion exchange literature. In addition, a sample calculation of a train of three crystalline silicotitanate (CST) IX columns in series was made using both the SpeedUp model and Purdue University's VERSE-LC code. All test cases showed excellent agreement between the SpeedUp model results and the test data. The model can be readily used for SuperLig{trademark} ion exchange resins, once the experimental data are complete.

Hang, T.

2000-03-06

60

Ion exchange as a tertiary treatment  

E-print Network

I. ON EXCHANGE AS A TERTIARY TRFATNENT A Thesis By RONALD DAVID NESTERVELT Submitted to the Graduate College of the Texas A&H University in partial fulfillment of the requirements for thc degree of NASTER OF SCIENCE Nay 1968 C 1 V I L F. NC... I NF. I'. 8 INC ION EXCHANGE AS A TERTIARY TREATMENT A Thesis By RONALD DAVID VESTERVELT Approved as to style and content by , n 7 (Chairma of Comm ttee (Member) +PL Head of D partment) Member ) May 1968 ACKNOWLEDGMENTS I wish to extend...

Westervelt, Ronald David

2012-06-07

61

Syntheses and the Main Properties of Fiban Fibrous Ion Exchangers  

Microsoft Academic Search

The works on synthesis and main properties of fibrous ion exchangers are reviewed in the paper. The main attention is paid to the FIBAN materials found practical applications in water treatment and air purification processes. The following methods for preparation of ion exchange fibers have been considered: mechanical mixing of inert fiber?forming polymer solutions or melts with finely dispersed ion?exchangers

V. S. Soldatov

2008-01-01

62

Electrically switched cesium ion exchange. FY 1997 annual report  

Microsoft Academic Search

This paper describes the Electrically Switched Ion Exchange (ESIX) separation technology being developed as an alternative to ion exchange for removing radionuclides from high-level waste. Progress in FY 1997 for specific applications of ESIX is also outlined. The ESIX technology, which combines ion exchange and electrochemistry, is geared toward producing electroactive films that are highly selective, regenerable, and long lasting.

M. A. Lilga; R. J. Orth; J. P. H. Sukamto

1997-01-01

63

Ion Exchange Temperature Testing with SRF Resin  

SciTech Connect

Ion exchange using the Spherical Resorcinol-Formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection for use in the Pretreatment Facility of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in an at-tank deployment for removing 137Cs. Recent proposed changes to the WTP ion exchange process baseline indicate that higher temperatures (50°C) to alleviate post-filtration precipitation issues prior to reaching the ion exchange columns may be required. Therefore, it is important to understand the behavior of SRF resin performance under the conditions expected with the new equipment and process changes. This research examined the impact of elevated temperature on resin loading and resin degradation during extended solution flow using elevated temperature (45°, 50°, 55°, 60°, 65°, 75°C). Testing for extended times at elevated temperatures showed that the resin does degrade and loading capacity is reduced at and above 45°C. Above 60°C the resin appears to not load at all.

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

2012-03-01

64

Water dissociation in ion-exchange membrane electrodialysis  

Microsoft Academic Search

When an electrical current larger than the limiting current density passes across an ion-exchange membrane, H+ ions and OH? ions are generated and transported in a water dissociation layer formed between the ion-exchange membrane and the boundary layer. Water dissociation reactions consist of a forward reaction and a reverse reaction. The forward reaction rate increases along with the increase of

Yoshinobu Tanaka

2002-01-01

65

Multiple Bennett acceptance ratio made easy for replica exchange simulations  

NASA Astrophysics Data System (ADS)

In this paper, we illustrate a practical technique to improve the efficiency of the so-called multiple Bennett acceptance ratio (MBAR) estimator [Shirts and Chodera, J. Chem. Phys. 129, 124105 (2008)] for computing thermodynamic expectations of physical quantities, from samples drawn from Hamiltonian or temperature replica exchange simulations. The methods exploit the Crooks fluctuation theorem [Crooks, J. Stat. Phys. 90, 1481 (1998)] for accurately evaluating the partition functions ratios of neighboring replicas, thus providing an excellent initial guess for the MBAR iterative procedure.

Procacci, Piero

2013-09-01

66

Sorption of tellurium ion from aqueous solutions by anion-exchangers and amphoteric ion-exchangers  

SciTech Connect

Sorption of tellurium from solutions of telluric acid under dynamic and static conditions by anion-exchangers and amphoteric ion-exchangers containing various ionic groups was studied and the influence of the ion form, pH of the medium, presence of electrolytes, and the H/sub 6/TeO/sub 6/ concentration in the original solutions was determined. The mechanism of sorption of tellurium (VI) by anion-exchangers was deduced from sorption and IR-spectroscopic data. Differences in the behavior of tellurium and selenium were used for separating these elements in 0.05 N H/sub 2/SeO/sub 4/ + 0.05 N H/sub 6/TeO/sub 6/ solution of pH = 1.0 with the aid of EDE-10P anion-exchange resin.

Dreipa, E.F.; Pakholkov, V.S.; Luk'yanov, S.A.

1981-10-20

67

Equilibrium isotherms for harmful ions sorption using nano zirconium vanadate ion exchanger  

Microsoft Academic Search

Harmful ions such as cesium, cobalt and nickel were removed from aqueous solutions using nano zirconium vanadate ion exchangers that prepared using three different techniques and their organic hybrids. Different processing parameters that affect on sorption efficiency were studied. All prepared ion exchangers and their composites have high uptake affinity for cesium removal. The removal capacities of the ion exchangers

M. M. Abd El-Latif; M. F. Elkady

2010-01-01

68

Ion exchange properties of humus acids  

NASA Astrophysics Data System (ADS)

Ion exchange equilibriums in a complex of brown humic acids (HAs) and related fulvic acids (FAs) with cations (H+, K+, Na+, Ca2+, Mg2+, Zn2+, Mn2+, Cu2+, Fe3+, and Al3+) have been studied, and the activity coefficients of the acid monoionic forms have been determined. The composition of the stoichiometric cell in the system of black and brown HAs and related FAs in a leached chernozem of the Ob' region has been calculated with consideration for the earlier studies of the ion exchange properties of black HAs and related FAs. It has been shown that hydrogen, calcium, magnesium, aluminum, and iron are the major components in the exchange complex of humus acids in the leached chernozem with the other cations being of subordinate importance. In spite of some differences between the analytical and calculated compositions of the humus acids, the results of the calculations can be considered satisfactory. They indicate that calculations are feasible for such complex objects as soils, and their accuracy will improve with the expansion of the experimental studies. The physicochemical simulation of the transformation of the humus acid composition under different acid-base conditions shows that the contents of most cations decrease under alkalization, and hydroxides or carbonates become the most stable forms of these cations. Under the acidification of solutions, the binding of alkaline and alkaline-earth elements by humus acids decreases and the adsorption of iron and aluminum by humus acids increases.

Shoba, V. N.; Chudnenko, K. V.

2014-08-01

69

Removal of natural organic matter by ion exchange.  

PubMed

Ion exchange is an effective method for removing humic substances from drinking water supplies. We have explored a range of anion exchangers for removal of natural organic matter (NOM), both as isolated from surface waters and after fractionation into four fractions based on hydrophobic and hydrophilic properties. Resins of open structure and high water content are confirmed as the better performers, being very efficient at removal of any charged material, especially that of smaller molecular size. Quaternary ammonium resins containing polar groups are especially effective. The presence of a neighbouring OH group close to the quaternary nitrogen, heteroatoms in the bridge between the exchange site and the polymer backbone, a secondary amino group as the exchange site, or a low ratio of carbon to quaternary nitrogen is beneficial. A suitable balance of polar and non-polar regions in the resin structure appears to be required. Weakly basic amino groups may have a greater affinity for hydrophilic counter ions than quaternary ammonium groups, but generally there are fewer charged sites in the resin at neutral pH. Nevertheless, weak base resins have NOM uptakes nearly as high as strong base resins of similar water content. Water content was found to be the most important parameter, though the effect was less pronounced for strong base resins. For weak base resins of low charge density a non-electrostatic mechanism involving hydrogen bonding of the undissociated acidic species in the NOM to the unprotonated amino groups on the resins is proposed. PMID:12448554

Bolto, Brian; Dixon, David; Eldridge, Rob; King, Simon; Linge, Kathryn

2002-12-01

70

Synthesis of perrhenic acid using ion exchange method  

Microsoft Academic Search

The paper presents results of the study for obtaining perrhenic acid from aqueous ammonium perrhenate solutions by ion exchange. Two ways of perrhenic acid synthesis have been examined: sorption of perrhenate anion on selected anion exchange resins (followed by elution of the sorbed rhenium as HReO4), and sorption of ammonium ion on selected cation exchange resins. The method of ammonium

K. Leszczy?ska-Sejda; G. Benke; A. Chmielarz; S. Krompiec; S. Michalik; M. Krompiec

2007-01-01

71

Ion exchange selectivity of a perfluorosulfonate ionomer  

E-print Network

and evaluation of my research. Gratitude is also extended to Robert B. Moore III for assistance with the preparation of columns for the HPLC, luminescence data and for verification of the many chromatographs that we ob- tained. TABLE OF CONTENTS... on Elution of Viologens 10 Effect of Organic Modifier on Elution of Pyridinium Zons 11 Elution of Pyridinium Zone with TMA-Cl as Eluent. 21 23 24 27 31 33 12 Ion Exchange Selectivity of Nafion Based HPLC Column 35 13 Elution of P-C from Column N...

Wilkerson, James Edward

2012-06-07

72

Ion exchange polymers and method for making  

NASA Technical Reports Server (NTRS)

An ion exchange polymer comprised of an alkali metal or alkaline earth metal salt of a poly(carboxylic acid) in a poly(vinyl acetal) matrix is described. The polymer is made by treating a mixture made of poly(vinyl alcohol) and poly(acrylic acid) with a suitable aldehyde and an acid catalyst to cause acetalization with some cross-linking. The material is then subjected to an alkaline aqueous solution of an alkali metal salt or an alkali earth metal salt. All of the film forming and cross-linking steps can be carried out simultaneously, if desired.

Philipp, Warren H. (inventor); Street, Kenneth W., Jr. (inventor)

1994-01-01

73

Biodegradation of ion-exchange media  

SciTech Connect

The purpose of this study was to investigate further the potential for ion-exchange media (resin beads or powdered filter media) to support biological growth. A mixed microbial culture was grown from resin wastes obtained from the BNL HFBR by mixing the resin with a nutrient salt solution containing peptone and yeast extract. Bacterial and fungal growths appeared in the solution and on the resins after 7 to 10 days incubation at 337)degree)C. The mixed microbial cultures were used to inoculate several resin types, both irradiated and unirradiated. 12 refs., 5 tabs.

Bowerman, B.S.; Clinton, J.H.; Cowdery, S.R.

1988-01-01

74

Ion exchange modules formed from polyhipe foam precursors  

Microsoft Academic Search

Homogeneous, highly porous, low density, open cellular polyhipe polymer (PHP) has been produced by polymerisation of a high internal phase emulsion. Its surface properties were modified by sulphonation. By incorporating Na+ ions onto the sulphonated PHP surfaces a modular form of ion exchange resin capable of effective exchange with metal ions in solution was produced. Isotherms were measured for samples

R. J. Wakeman; Z. G. Bhumgara; G. Akay

1998-01-01

75

Ion Exchange Chromatography and Spectrophotometry: An Introductory Undergraduate Laboratory Experiment.  

ERIC Educational Resources Information Center

Describes an experiment in which students use ion exchange chromatography to separate a mixture of chloro complexes of transition metal ions and then use spectrophotometry to define qualitatively the efficiency of the ion exchange columns. Background information, materials needed, and procedures used are included. (JN)

Foster, N.; And Others

1985-01-01

76

Ion exchange and redox reactions in metal-ion exchanger nanocomposites  

NASA Astrophysics Data System (ADS)

The reducing sorption of oxygen dissolved in water with the use of metal-containing nanocomposites is considered taking into account the bifunctional nature of sorbents possessing both redox and ion exchange properties. A physicochemical model of the process including metal particle dispersity, their distribution over a grain, and the special features of the chemical oxidation of metals was used. Based on this model, a mathematical formulation of the problem including the stage of the interdiffusion of metal ions (metal oxidation products) and hydrogen ions (matrix counterions) is given.

Kipriyanova, E. S.; Konev, D. V.; Kravchenko, T. A.; Khorol'skaya, S. V.

2012-07-01

77

Radionuclide Leaching from Organic Ion Exchange Resin  

SciTech Connect

Laboratory tests were performed to examine the efficacy of leach treatments for decontaminating organic ion exchange resins (OIER), which have been found in a number of samples retrieved from K East Basin sludge. Based on process records, the OIER found in the K Basins is a mixed-bet strong acid/strong base material marketed as Purolite{trademark} NRW-037. Radionuclides sorbed or associated with the OIER can restrict its disposal to the Environmental Restoration Disposal Facility (ERDF). The need for testing to support development of a treatment process for K Basin sludge has been described in Section 4.2 of ''Testing Strategy to Support the Development of K Basins Sludge Treatment Process'' (Flament 1998). To help understand the effects of anticipated OIER elutriation and washing, tests were performed with well-rinsed OIER material from K East Basin floor sludge (sample H-08 BEAD G) and with well-rinsed OIER having approximately 5% added K East canister composite sludge (sample KECOMP). The rinsed resin-bearing material also contained the inorganic ion exchanger Zeolon-900{trademark}, a zeolite primarily composed of the mineral mordenite. The zeolite was estimated to comprise 27 weight percent of the dry H-08 BEAD G material.

Delegard, C.H.; Rinehart, D.E.

1999-04-02

78

Mineral Separation in a CELSS by Ion-exchange Chromatography  

NASA Technical Reports Server (NTRS)

Operational parameters pertinent to ion exchange chromatography separation were identified. The experiments were performed with 9 mm diameter ion exchange columns and conventional column accessories. The cation separation beds were packed with AG 50W-X2 strong acid cation exchange resin in H(+) form and 200-400 dry mesh particle size. The stripper beds used in some experiments were packed with AG 1-XB strong base cation exchange resin in OH(-) form and 200-400 dry mesh particle size.

Ballou, E. V.; Spitze, L. A.; Wong, F. W.; Wydeven, T.; Johnson, C. C.

1982-01-01

79

TECHNICAL COMPARISON OF CANDIDATE ION EXCHANGE MEDIA FOR SMALL COLUMN ION EXCHANGE (SCIX) APPLICATIONS IN SUPPORT OF SUPPLEMENTAL LAW PRETREATMENT  

SciTech Connect

At-tank supplemental pretreatment including both filtration and small column ion exchange is currently under evaluation to facilitate salt waste retrieval and processing in the Hanford tank farms. Spherical resorcinol formaldehyde (sRF) resin is the baseline ion exchange resin for use in the Waste Treatment and Immobilization Plant (WTP). This document provides background and technical rationale to assist in determining whether spherical resorcinol formaldehyde (sRF) is also the appropriate ion exchange resin for supplemental LAW pretreatment processes and compares sRF with crystalline silicotitanate (CST) as potential supplemental pretreatment ion exchange media.

RAMSEY AA; THORSON MR

2010-12-28

80

Electrodialytic separation of alkali-element ions with the aid of ion-exchange membranes  

Microsoft Academic Search

Electrodialytic separation of ions bearing charges of the same sign with the aid of ion-exchange membranes has been examined in the literature in relation to the so-called ideal membranes, which do not exhibit selectivity with respect to one ion type in ion exchange. It has been shown that separation on such membranes is effective only for counterions differing in size

V. S. Gurskii; L. N. Moskvin

1988-01-01

81

Scintillating 99Tc Selective Ion Exchange Resins  

SciTech Connect

Scintillating technetium (99Tc) selective ion exchange resins have been developed and evaluated for equilibrium capacities and detection efficiencies. These resins can be utilized for the in-situ concentration and detection of low levels of pertechnetate anions (99TcO4-) in natural waters. Three different polystyrene type resin support materials were impregnated with varying amounts of tricaprylmethylammonium chloride (Aliquat 336) extractant, several different scintillating fluors and wavelength shifters. The prepared resins were contacted batch-wise to equilibrium over a wide range of 99TcO4- concentrations in natural water. The measured capacities were used to develop Langmuir adsorption isotherms for each resin. 99Tc detection efficiencies were determined and up to 71.4 ± 2.6% was achieved with some resins. The results demonstrate that a low level detection limit for 99TcO4- in natural waters can be realized.

Mitchell Greenhalgh; Richard D. Tillotson

2012-07-01

82

Radiation testing of organic ion exchange resins  

SciTech Connect

A number of ion exchange materials are being evaluated as part of the Tank Waste Remediation System (TWRS) Pacific Northwest Laboratory (PNL) Pretreatment Project for the removal of {sup 137}Cs from aqueous tank wastes. Two of these materials are organic resins; a phenol-formaldehyde resin (Duolite CS-100) produced by Rohm and Haas Co. (Philadelphia, Pennsylvania) and a resorcinol-formaldehyde (RF) resin produced by Boulder Scientific Co. (Mead, Colorado). One of the key parameters in the assessment of the organic based ion exchange materials is its useful lifetime in the radioactive and chemical environment that will be encountered during waste processing. The focus of the work presented in this report is the radiation stability of the CS-100 and the RF resins. The scope of the testing included one test with a sample of the CS-100 resin and testing of two batches of the RF resin (BSC-187 and BSC-210). Samples of the exchangers were irradiated with a {sup 60}Co source to a total absorbed dose of 10{sup 9} R over a period of 5 months in a static (no flow) and a flowing configuration with neutralized current acid waste (NCAW) simulant as a feed. Based on a maximum concentration of {sup 137}Cs on the resin that would result from processing NCAW, this dose represents an operational period of at least 150 days for the RF resin and at least 1260 days for the CS-100 resin. Gas generation in the static experiment was continuously monitored and G values (molecules of gas per 100 eV) were determined for each species. Resin samples were obtained periodically and the equilibrium behavior of the resins was assessed by determining the distribution coefficients (K{sub d}s). Structural information was also obtained by {sup 13}C cross polarization magic angle (CPMAS) nuclear magnetic resonance (NMR) spectrometry and Fourier Transform Infrared (FTIR) spectroscopy so that changes to the chemical structure could be correlated with changes in K{sub d}.

Carlson, C.D.; Bray, L.A.; Bryan, S.A. [and others

1995-09-01

83

Solute affinity in ion-exchange displacement chromatography  

Microsoft Academic Search

In this paper a new graphical method, derived from the Steric Mass Action model of non-linear ion-exchange chromatography, is presented for the determination of solute affinity in ion exchange displacement systems. The affinity of solutes in these systems is described by a dynamic affinity parameter which is a function of the linear steric mass action parameters of the solutes and

Clayton A. Brooks; Steven M. Cramer

1996-01-01

84

Seawater desalination: Boron removal by ion exchange technology  

Microsoft Academic Search

Ion exchange is the most appropriate technology to remove boron selectively from desalinated seawater. Reverse osmosis, necessary to reduce the salinity of seawater down to drinking water levels, can be combined with selective ion exchange. This combination reduces the overall capital cost and operating cost compared to an “all RO” solution. This paper presents the principles for an optimised combination

Cyril Jacob

2007-01-01

85

Decrystallization of glass-ceramics under ion exchange diffusion  

Microsoft Academic Search

Experimental results of studying ion exchange process in glass-ceramics are presented. For the first time, it is discovered that the process may result in the disappearance of the crystalline phase in the layers undergoing ion exchange diffusion. This new phenomenon has been called the effect of decrystallization. The effect has been observed in a ceramic material formed out of a

D. K Tagantsev

1999-01-01

86

Rupture Loop Annex (RLA) ion exchange vault entry and characterization  

SciTech Connect

This engineering report documents the entry and characterization of the Rupture Loop Annex Ion Exchange (RLAIX) Vault located near the 309 Building`s Plutonium Recycle Test Reactor (PRTR). Twelve ion exchange columns were found in the vault. Some of which contained transuranics, Cs 137, and Co 60. The characterization information is necessary for future vault cleanout and column disposal.

Ham, J.E.

1996-01-04

87

Preparation of site-selective ion-exchange resins  

SciTech Connect

Ion-exchange resins were prepared by copolymerization of styrenic monomers with metal ion complex compounds bearing polymerizable ligands. Removal of the metal ions by acid washing produced sites in the resins which contained ligands configured to match the bonding characteristics of the ions used in their construction. This template procedure was performed with Ni{sup 2+} and Cu{sup 2+} ions, and comparisons were made of exchange capacities and equilibrium constants for templated and untemplated resins. Templated resins showed order of magnitude capacity preferences for the ion used in their preparation. Equilibrium constants were found to be inversely related to capacities.

Harkins, D.A.; Schweitzer, G.K. (Univ. of Tennessee, Knoxville (USA))

1991-01-01

88

Synthesis, ion exchange properties and analytical applications of stannic silicomolybdate: Effect of temperature on distribution coefficients of metal ions  

Microsoft Academic Search

Stannic silicomolybdate was synthesized at pH 0.63 .The experimental parameters such as order of mixing, mixing volume ratio, pH, stirring time, drying temperature were established for the synthesis of the material. The ion exchange capacity of Ca2+ was improved from 0.53 to 1.73meq\\/g for this newly synthesized material. The reproducibility of the product formed was checked. The exchanger was characterized

Syed Ashfaq Nabi; Amjad Mumtaz Khan

2006-01-01

89

Improved Amphoteric Ion Exchanger and Its Manufacturing Method.  

National Technical Information Service (NTIS)

This invention relates to an amphoteric ion exchanger comprising a block copolymer composed of a polymer chain poly A exp - having a cation exchange group, poly B exp + polymer chain having an anion exchange group, and poly C polymer chain not having an i...

T. Kodaka, H. Onuma

1985-01-01

90

Vibrational spectroscopy of ion exchange membranes  

NASA Astrophysics Data System (ADS)

Infrared Spectroscopy (IR) and density functional theory (DFT) calculations were used to study Nafion, a sulfonated tetrafluoroethylene ionomer used as the electrolyte material of choice for polymer electrolyte membrane fuel cells (PEMFCs). A methodology is described for assignment of infrared peaks in terms of mechanically coupled internal coordinates of near neighbor functional groups. This work demonstrates (chapter 2--4) the use of ionomer functional group internal coordinate coupling analysis to assign two key Nafion peaks formerly assigned as the sulfonate symmetric stretch (1056 cm -1) and a COC (A) vibrational mode (971 cm-1). The experiments and theory complement each other to show that the dominate motions of the 1056 cm-1 and 971 cm-1 modes are attributed to the COC (A) and the sulfonate stretch respectively, exactly reverse of the convention used for decades. The salient point is that both peaks result from mechanically coupled internal coordinates of both functional groups. This explains why the 1056 cm-1 and 971 cm -1 peaks shift together with changes in the sulfonate group environment (i.e., ion exchange or membrane dehydration). The assignments, correlated with extensive literature data, and new data showing both peaks vanishing upon rigorous dehydration (i.e. conversion of a C3V deprotonated -SO3- to a C1 -SO3H) of the membrane, were based on the correlation of observed IR peaks with animations of mechanically coupled internal coordinates obtained by DFT calculations. Further, the above methodology was augmented with polarization modulated infrared reflection-adsorption spectroscopy (PM-IRRAS) to elucidate the Nafion ionomers functional groups that participate in self-assembly of Nafion onto Pt surfaces. A model for Nafion adsorption onto Pt shows that the Nafion side-chain sulfonate and CF3 co-adsorbates are structural components of the Nafion-Pt interface. The DFT-spectroscopy method of assigning peaks in terms of mechanically coupled internal coordinates was augmented with ion-exchange-induced shifts for extensive assignments of Nafion IR peaks (explicit and deconvoluted). Chapter 5 focuses on the durability of the membrane electrode assembly (MEAs) in direct methanol fuel cells (DMFCs). The MEA catalyst-polymer interfacial region was examined for degradation modes.

Kumari, Dunesh

91

Development of an electrically switched ion exchange process for selective ion separations  

Microsoft Academic Search

The electrically switched ion exchange (ESIX) process, being developed at Pacific Northwest National Laboratory, provides an alternative separation method to selectively remove ions from process and waste streams. In the ESIX process, in which an electroactive ion exchange film is deposited onto a high surface area elecrotrode, uptake and elution are controlled directly by modulating the electrochemical potential of the

Scot D. Rassat; Johanes H. Sukamto; Rick J. Orth; Michael A. Lilga; Richard T. Hallen

1999-01-01

92

Ion exchange capacity of Nafion and Nafion composites  

SciTech Connect

The ion exchange capacity of recast Nafion films and composites of Nafion and polystyrene microbeads is determined by titration. Composite formation enhances exchange capacity; exchange capacity increases with the surface area microbeads in the composite. For recast films, an equivalent weight of 996 {+-} 24 is found, whereas the lowest equivalent weight (highest exchange capacity) found for composite is 878 {+-} 8. This suggests that {approx_gt} 13% of the exchange sites within recast films are inaccessible for ion exchange; for 1,100 equivalent weight material, {approx_gt} 25% of the sulfonates are inaccessible. Equivalent weight results are consistent with an ordered interfacial domain between Nafion and the microbeads. A fractal model based on microbead radii, microbead fraction, and interfacial domain thickness provides a predictive model for designing composites with increased exchange capacity and cation transport.

Chen, T.Y.; Leddy, J.

2000-03-21

93

Synthesis, Ion Exchange Properties, and Applications of Amorphous Cerium(III) Tungstosilicate  

Microsoft Academic Search

A novel hetropolyacid-based cation exchanger cerium(III) tungstosilicate was synthesized in amorphous form by mixing tungstosilisic acid (TSA) solutions to cerium(III) nitrate solutions at different Ce:TSA ratios. The materials were precipitated from the liquid phase by raising the pH of the solutions using sodium hydroxide. The produced ion exchange powders were characterized using powder X-ray diffractometry, thermogravimetry, infrared spectrometry, inductively coupled

R. Yavari; S. J. Ahmadi; Y. D. Huang; G. Bagheri

2008-01-01

94

Cesium Ion Exchange Loading Kinetics Testing with SRF Resin  

SciTech Connect

Ion exchange using the Spherical Resorcinol-Formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection for use in the Pretreatment Facility of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in an at-tank deployment for removing 137Cs. Recent proposed changes to the WTP ion exchange process baseline indicate that loading may include a broader range of sodium molarities (2 to 8 M) due to caustic leaching and higher temperatures (50°C) to alleviate post-filtration precipitation issues prior to reaching the ion exchange columns. Therefore, it is important to understand the behavior of SRF resin performance under the conditions expected with the new equipment and process changes. This research examined the impact of linear load velocity (4, 6, 8 cm/min), initial sodium concentration (2, 5, 8 M), initial sodium-to-cesium ratio (1.4E+05, 2.1E+05, 2.8E+05 mol/mol), initial sodium-to-hydroxide ratio (2.0, 3.0, 4.0 mol/mol), and resin degradation during extended solution flow using elevated temperature (45°, 50°, 55°, 60°, 65°, 75°C). Testing was performed using a~2mL column packed with SRF resin with feed flowing through it in an up-flow pattern. Samples were taken at set intervals and the data analyzed to help understand the impact of these conditions on the SRF resin performance. It was found that the loading kinetics were not significantly impacted by the sodium concentration over the range tested. However, the loading kinetics were impacted by the linear load velocity. These results indicated that at the test temperature, the adsorption of cesium is strongly dependent on mass transfer through the film and not significantly impacted by interparticle diffusion. Testing for extended times at elevated temperatures showed that the resin does degrade and loading capacity is reduced at and above 45°C. Above 60°C the resin appears to not load at all.

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

2012-11-02

95

Concept of advanced spent fuel reprocessing based on ion exchange  

SciTech Connect

Reprocessing based on ion exchange separation is proposed as a safe, proliferation-resistant technology. Tertiary pyridine resin was developed for ion exchange reprocessing. Working medium of the separation system is not nitric acid but hydrochloric acid aqueous solution. The system does not involve strong oxidizing reagent, such as nitric acid but involve chloride ions which works as the week neutron absorbers. The system can be operated at ambient temperatures and pressure. Thus the HCl-ion-exchange reprocessing is regarded as an inherently safe technology. Another advantage of HCl ion-exchange reprocessing is the proliferation-resistant nature. Both U(VI) and Pu(IV) ions are adsorbed in the pyridine type anion exchange resin at relatively high HCl concentration of 6 M. At this condition, the adsorption distribution coefficient of Pu(IV) is smaller than that of U(VI). When uranium is eluted from the resin in the column, plutonium is simultaneously eluted from the column; Pu is recovered with uranium in the front part of uranium adsorption band. Pu(IV) can not be left in the resin after elution of uranium. The use of HCl in the ion-exchange reprocessing causes the problem of the plant materials. Sophisticated material technology is necessary to realize the ion exchange reprocessing using HCl. The technology is so sophisticated that only highly developed countries can hold the technology, thus the technology holding countries will be limited. The plant, therefore, cannot be built under hidden state. In addition, another merit of the process would be the simplicity in operation. One phase, i.e., ion exchange resin is immobile, and the aqueous solution is the only mobile phase. Plant operation is made by the control of one aqueous solution phase. The plant simplicity would ease the international safeguard inspection efforts to be applicable to this kind of reprocessing plant. The present work shows the basic concept of ion exchange reprocessing using HCl medium. Furthermore, the ion exchange is appropriate for multi-element mutual separation rather than single element extraction. In the future, ion exchange reprocessing would be expected to be the comprehensive separation process for spent fuels to recover precious and usable elements and to reduce the amount of wastes. (authors)

Suzuki, Tatsuya; Takahashi, Kazuyuki; Nogami, Masanobu; Nomura, Masao; Fujii, Yasuhiko [Tokyo Institute of Technology, 2-12-1 O-okayama, Meguroku, Tokyo 152-8550 (Japan); Ozawa, Masaki [Tokyo Institute of Technology, 2-12-1 O-okayama, Meguroku, Tokyo 152-8550 (Japan)]|[Japan Atomic Energy Agency (Japan); Koyama, Shinichi [Japan Atomic Energy Agency (Japan); Mimura, Hitosi [Tohoku University (Japan); Fujita, Reiko [Toshiba Corporation (Japan)

2007-07-01

96

A mathematical relationship for the explanation of ion exchange for boron adsorption  

Microsoft Academic Search

The present study was undertaken to investigate a method for boron removal from wastewaters from boric acid and borax plants. The ion-exchange method is effective for the removal of boron from solution. The experimental results under different initial concentrations are first converted into dimensionless variables by taking ratios of volumes and concentrations and subsequently plotted on double logarithmic graph papers.

Sami ?ahin

2002-01-01

97

Tc-99 Ion Exchange Resin Testing  

SciTech Connect

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

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

2010-08-01

98

Vitrification of ion exchange materials. Innovative technology summary report.  

National Technical Information Service (NTIS)

Ion exchange is a process that safely and efficiently removes radionuclides from tank waste. Cesium and strontium account for a large portion of the radioactivity in waste streams from US Department of Energy (DOE) weapons production. Crystalline silicoti...

1999-01-01

99

WASTEWATER DEMINERALIZATION BY CONTINUOUS COUNTER-CURRENT ION EXCHANGE PROCESS  

EPA Science Inventory

A wastewater demineralization study employing a 38 lpm (10 gpm) continuous counter-current ion exchange pilot plant, manufactured by the Chemical Separations Corporation, Oak Ridge, Tennessee, has been conducted at the County Sanitation Districts, Pomona Research Facility, Pomona...

100

FRACTIONATION OF COMPLEX MIXTURES USING AND ION-EXCHANGE METHODOLOGY  

EPA Science Inventory

Fractionation of particle emission extracts captured from complex combustion mixtures gas performed upon environmental samples using an ion-exchange technique. aptured emissions from hazardous waste, municipal and medical/pathological incinerators along with urban air imputed by ...

101

Samarium Ion Exchanged Montmorillonite for High Temperature Cumene Cracking Reaction  

NASA Astrophysics Data System (ADS)

Montmorillonite clay is cation exchanged with samarium and its catalytic influence in cumene cracking reaction is investigated. Effect of exchange with sodium ions on further exchange with samarium ions is also noted. Acidity measurements are done using Temperature Programmed Desorption (TPD) of ammonia. The retention of basic structure is proved from FTIR spectra and XRD patterns. Elemental analysis result shows that samarium exchange has occurred, which is responsible for the higher catalytic activity. Surface area and pore volume remains more or less unaffected upon exchange. Thermogravimetric analysis indicates the enhanced thermal stability on exchanging. Cumene cracking reaction is carried out at atmospheric pressure in a fixed bed glass reactor at 673 K. The predominance of Brųnsted acidity is confirmed from high selectivity to benzene.

Binitha, N. N.; Silija, P. P.; Suraj, V.; Yaakob, Z.; Sugunan, S.

2011-02-01

102

Chromatographic Separations of Metal Ions on Zirconium Tungstoarsenate Impregnated Ion-Exchange Papers  

Microsoft Academic Search

A new heteropolyacid salt ion-exchanger, zirconium tungstoarsenate, has been used for preparing impregnated ion-exchange papers. Twenty-nine metal ions have been chromatographed and RF values determined in seven different mixed solvent systems containing 1-propanol and HNO or HCl. On the basis of the difference in selectivities for different metal ions on impregnated papers, a large number of binary and ternary separations

Ajay K. Jain; Sushma Agrawal; Raj P. Singh

1980-01-01

103

Ion-exchange chromatography by dicarboxyl cellulose gel  

Microsoft Academic Search

A new column packing material for ion-exchange chromatography was prepared from cellulose gel by periodate oxidation followed by chlorite oxidation to form spatially paired carboxyl groups (dicarboxyl cellulose, DCC). The carboxyl group was quantitatively introduced to spherical cellulose gel by controlling the extent of oxidation. The DCC gels were examined for their ion-exchange activity for various amines at pH of

Ung-Jin Kim; Shigenori Kuga

2001-01-01

104

Ion exchange membranes blended by cellulose cuoxam with alginate  

Microsoft Academic Search

Ion exchange membranes were prepared by coagulating a blend of 6.4 wt% cellulose cuoxam (I) and 3 wt% aqueous alginate solution (II). The tensile strength of both the dry and wet blend membranes was obviously higher than that of membranes made of pure alginate. The value of ion exchange capacity was 1.25 meq\\/g dry membrane for blend membrane in which

Lina Zhang; Daochun Zhou; Hao Wang; Shuyao Cheng

1997-01-01

105

Optical waveguides fabricated by transition element ions exchange in some commercial and special optical glasses  

NASA Astrophysics Data System (ADS)

We present a fabrication and properties study of planar optical waveguides fabricated in a variety of commercially available as well as non-commercial special silicate-based optical glasses. The exchanged ions coming from external sources were Ag +, Cu +, Cu 2+ and Er 3+. The reduction of Ag + to Ag 0 from which the high optical losses of waveguides may originate was strongly enhanced when the glass contained reducing fining agents as As 2O 3 or Sb 2O 3. The Cu 2+ ion-exchange proceeded very quickly and resulted in the fabrication of waveguides with negligible birefringence. The samples containing exclusively Cu + exhibited very strong blue-green luminescence even in the cases of very low copper content in the exchanged surface layers. The purely thermal erbium ion-exchange was successful only in lithium containing glasses; when using the electric-field-assisted ion-exchange the erbium containing waveguides were fabricated also in several sodium-rich and sodium-potassium glasses. The shallow erbium-containing surface layers were deepened by the post-exchange annealing of the as-exchanged samples. The properties of the fabricated waveguides are discussed from the point of view of the composition of substrate glasses, taking into account the ratios of the bridging and non-bridging oxygen atoms in the glass matrices and the presence of fining agents.

Spirkova, Jarmila; Tresnakova-Nebolova, Pavlina; Mika, Martin

2004-03-01

106

Removal of natural organic matter by ion exchange  

Microsoft Academic Search

Ion exchange is an effective method for removing humic substances from drinking water supplies. We have explored a range of anion exchangers for removal of natural organic matter (NOM), both as isolated from surface waters and after fractionation into four fractions based on hydrophobic and hydrophilic properties. Resins of open structure and high water content are confirmed as the better

Brian Bolto; David Dixon; Rob Eldridge; Simon King; Kathryn Linge

2002-01-01

107

Coccolith B\\/Ca ratios using SIMS ion probe analysis  

Microsoft Academic Search

B\\/Ca ratios are proposed as a paleo-carbonate ion or paleo-pH proxy due to the preferential incorporation of borate ion into the calcite lattice, relative to boric acid which is the dominant species of B at lower pH. The relative importance of cellular regulation vs external pH on the carbonate B\\/Ca remains to be characterized for most organisms. Here we describe

H. Stoll; N. Shimizu; G. Langer

2009-01-01

108

Water dissociation reaction generated in an ion exchange membrane  

Microsoft Academic Search

Based on pH measurement in water dissociation experiments, the mechanism of a water dissociation (water splitting) reaction is discussed assuming that the reaction is generated in a reaction layer formed in an ion exchange membrane and the reaction layer extends throughout the space in the membrane. The process is established to estimate the current efficiency for H+ and OH? ions

Yoshinobu Tanaka

2010-01-01

109

Stoichiometry of removal of natural organic matter by ion exchange.  

PubMed

Five anion exchange resins, including a magnetic ion exchange (MIEX) resin, were evaluated for removal of Suwannee River Fulvic Acid (SRFA) in the presence of bicarbonate and chloride. The charge density of SRFA, obtained by potentiometric titration, was used to perform charge balances for ion exchange reactions involving SRFA, bicarbonate, and chloride under different solution conditions. The results clearly show the equivalence of SRFA uptake and chloride release by ion exchange. Although the structure of the anion exchange resins did not affect the stoichiometry of the reaction, the polyacrylic resins did exhibit greater removal of SRFA than the polystyrene resins. The hindered removal of SRFA by the polystyrene resins was hypothesized to be a result of size exclusion. The MIEX resin, which has a polyacrylic structure, performed similarly to the other polyacrylic resins. For the MIEX resin, the separation factor for SRFA over chloride was approximately 8 times greater than for bicarbonate over chloride. This work provides an improved understanding of the interactions between natural organic matter (NOM), inorganic anions, and anion exchange resins, and should result in more effective applications of ion exchange for the removal of NOM in the treatment of drinking water. PMID:18284170

Boyer, Treavor H; Singer, Philip C

2008-01-15

110

Desalination of brackish waters using ion exchange media.  

SciTech Connect

An environmentally friendly method and materials study for desalinating inland brackish waters (i.e., coal bed methane produced waters) using a set of ion-exchange materials is presented. This desalination process effectively removes anions and cations in separate steps with minimal caustic waste generation. The anion-exchange material, hydrotalcite (HTC), exhibits an ion-exchange capacity (IEC) of {approx} 3 mequiv g{sup -1}. The cation-exchange material, an amorphous aluminosilicate permutite-like material, (Na{sub x+2y}Al{sub x}Si{sub 1-x}O{sub 2+y}), has an IEC of {approx}2.5 mequiv g{sup -1}. These ion-exchange materials were studied and optimized because of their specific ion-exchange capacity for the ions of interest and their ability to function in the temperature and pH regions necessary for cost and energy effectiveness. Room temperature, minimum pressure column studies (once-pass through) on simulant brackish water (total dissolved solids (TDS) = 2222 ppm) resulted in water containing TDS = 25 ppm. A second once-pass through column study on actual produced water (TDS = {approx}11,000) with a high carbonate concentration used an additional lime softening step and resulted in a decreased TDS of 600 ppm.

Pless, Jason D.; Krumhansl, James Lee; Nenoff, Tina Maria; Voigt, James A.; Phillips, Mark L. F.; Axness, Marlene; Moore, Diana Lynn

2005-01-01

111

Electrical and magnetic properties of ion-exchangeable layered ruthenates  

SciTech Connect

An ion-exchangeable ruthenate with a layered structure, K{sub 0.2}RuO{sub 2.1}, was prepared by solid-state reactions. The interlayer cation was exchanged with H{sup +}, C{sub 2}H{sub 5}NH{sub 3}{sup +}, and ((C{sub 4}H{sub 9}){sub 4}N{sup +}) through proton-exchange, ion-exchange, and guest-exchange reactions. The electrical and magnetic properties of the products were characterized by DC resistivity and susceptibility measurements. Layered K{sub 0.2}RuO{sub 2.1} exhibited metallic conduction between 300 and 13K. The products exhibited similar magnetic behavior despite the differences in the type of interlayer cation, suggesting that the ruthenate sheet in the protonated form and the intercalation compounds possesses metallic nature.

Sugimoto, Wataru [Faculty of Textile Science and Technology, Department of Fine Materials Engineering, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan)]. E-mail: wsugi@shinshu-u.ac.jp; Omoto, Masashi [Faculty of Textile Science and Technology, Department of Fine Materials Engineering, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan); Yokoshima, Katsunori [Faculty of Textile Science and Technology, Department of Fine Materials Engineering, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan); Murakami, Yasushi [Faculty of Textile Science and Technology, Department of Fine Materials Engineering, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan); Takasu, Yoshio [Faculty of Textile Science and Technology, Department of Fine Materials Engineering, Shinshu University, 3-15-1 Tokida, Ueda 386-8567 (Japan)

2004-12-01

112

Columnar studies with selective ion exchange  

SciTech Connect

Secondary recovery of oil using water or steam injection to pressurize the strata has highlighted the water softening process using acidic cation exchangers which are regenerated with brine followed by a polishing weakly acidic cation exchanger. Development of a program to produce bries with low hardness suitable for secondary oil recovery is described. Results of laboratory tests with various resins for softening brines are presented. Calculations for a typical plant using Ionac SR-1 to soften a 25% brine are included. (BLM)

McGarvey, F.X.; Gottlieb, M.C.

1981-12-01

113

Separation of ions on columns of cerium(IV) silicate, a new ion exchanger  

SciTech Connect

Six different samples of a new inorganic ion exchanger, cerium(IV) silicate, have been prepared under varying conditions. Ion-exchange capacity, IR, X-ray, thermogravimetry, composition, and distribution coefficients of many metal ions have been studied and discussed. Separations of Cr{sup III}-V{sup V}, Cu{sup II}-Bi{sup III}, Ti{sup IV}-Cr{sup VI}, and Cr{sup III}-Cr{sup VI} have been developed on columns of this ion exchanger.

Ghannadi-Marageh, M.; Husain, S.W.; Khanchi, A.R.; Ahmady, S.J. [Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of). Jaber Ibn Hayan Research Labs.] [Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of). Jaber Ibn Hayan Research Labs.

1999-01-01

114

Release and uptake of nutritive ions from the ion exchanger fertilizer  

Microsoft Academic Search

Summary  The present paper deals with an investigation of the problem of the gradual release of nutritive ions bound on ion exchangers.\\u000a Tomato plants were cultivated in a mixture of sand and ion exchanger fertilizer of different sized granulation. The check\\u000a plants were watered with a nutritive solution.\\u000a \\u000a At five time intervals the following portions of nutrients were measured: a. consumed

V. Sżkora; J. Matouš; F. Dubskż; J. Soukup

1972-01-01

115

Radioactive halos and ion microprobe measurement of Pb isotope ratios  

NASA Technical Reports Server (NTRS)

This investigation was to obtain, if possible, the Pb isotope ratios of both lunar and meteoritic troilite grains by utilizing ion microprobe techniques. Such direct in situ measurement of Pb isotope ratios would eliminate contamination problems inherent in wet chemistry separation procedures, and conceivably determine whether lunar troilite grains were of meteoritic origin. For comparison purposes two samples of meteoritic troilite were selected (one from Canyon Diablo) for analysis along with two very small lunar troilite grains (approximately 50-100 microns). It was concluded that the ion microprobe as presently operating, does not permit the in situ measurement of Pb isotope ratios in lunar or meteoritic troilite. On the basis of these experiments no conclusions could be drawn as to the origin of the lunar troilite grains.

Gentry, R. V.

1974-01-01

116

Properties of a Novel Ion-Exchange Film  

NASA Technical Reports Server (NTRS)

A new ion-exchange material (based on polyacrylic acid) and some of its analytical applications have been reported. This paper contains data on the ion-exchange properties of the film form of the material and its potential application to the decontamination of waste water and drinking water. The film has a high exchange capacity of 5 to 6 meq/g and a pK(sub a) of 5.7. The calcium form is the most effective for removing metal ions from solution, and the optimum pH range is between 5 and 7. The exchange rates are slower for the film than for bead and powder forms of the ion-exchange material; otherwise, the properties are similar. The film is effective when hard water solutions are employed and also when metal ions are in the complex matrix of waste water from electroplating. The film can be used in flow systems having a flow channel large enough to allow passage of turbid solutions.

Street, Kenneth W.; Hill, Carol M.; Philipp, Warren H.; Tanner, Stephen P.; Gorse, Joseph; Lusk, Amy; Taylor, Jason; Dickens, Jason

2004-01-01

117

Hydrous oxide ion-exchange compound catalysts  

DOEpatents

A catalytic material of improved activity which comprises a hydrous, alkali metal or alkaline earth metal or quaternary ammonium titanate, zirconate, niobate, or tantalate, in which the metal or ammonium cations have been exchange with a catalytically effective quantity of a catalyst metal, and which has been subsequently treated with a solution of a Bronsted acid.

Dosch, Robert G. (Albuquerque, NM); Stephens, Howard P. (Albuquerque, NM)

1990-01-01

118

Ion exchange polymers for anion separations  

DOEpatents

Anion exchange resins including at least two positively charged sites and a well-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene.

Jarvinen, G.D.; Marsh, S.F.; Bartsch, R.A.

1997-09-23

119

Ion exchange polymers for anion separations  

DOEpatents

Anion exchange resins including at least two positively charged sites and a ell-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene.

Jarvinen, Gordon D. (Los Alamos, NM); Marsh, S. Fredric (Los Alamos, NM); Bartsch, Richard A. (Lubbock, TX)

1997-01-01

120

Development and evaluation of ion exchange hollow fibers. [vinyl copolymers  

NASA Technical Reports Server (NTRS)

An ion exchange hollow fiber impregnated with a vinylpyridine base was developed. The basic exchange resin used to impart the necessary permselectivity to the hollow fiber is a copolymer of vinylpyridine and dibromoethane prepared according to Rembaum. A slight pressure was used to impregnate the exchange monomer mixture into the void structure of the fiber wall, and with maintenance of subambient temperatures, the rate of cross-linking is slow enough to allow the growing polymer to permeate the wall structure before significant increase in polymer molecular weight. These ion exchange fibers are produced from polyacrylonitrile hollow fibers with an appropriate wall structure that enables the impregnating vinylpyridine monomer mixture to form a truly semipermeable anion barrier after curing.

Smith, J. K.

1975-01-01

121

Evaluating Ion Exchange for Removing Radium From Groundwater  

Microsoft Academic Search

This article, the second in a series, focuses on the results of bench-and pilot-scale studies of ion exchange processes for radium removal from groundwater in Lemont, Ill. Batch and column studies indicated a very high resin selectivity for radium compared with common cations. Exhaustion-regeneration studies with a variety of resins showed that a standard gel-type strong-acid cation exchanger is most

Suresh Subramonian; Dennis Clifford; Winston Vijjeswarapu

1990-01-01

122

SODIUM NONATITANATE: A HIGHLY SELECTIVE INORGANIC ION EXCHANGER FOR STRONTIUM  

Microsoft Academic Search

Sodium nonatitanate (Na4Ti9O20), which is a highly selective inorganic ion exchanger for strontium, is regenerable, is radiation resistant, and has a high cation exchange capacity. This paper summarizes the test results with a variety of simulants for tank waste and groundwater streams that demonstrate the potential of this unique material. Sodium nonatitanate is most effective in an alkaline environment and

S. F. Yates; P. Sylvester

2001-01-01

123

Internally consistent representation of binary ion exchange equilibria  

Microsoft Academic Search

A model has been developed to obtain the thermodynamic parameters, i.e., the equilibrium constant and solid-phase activity coefficients, that describe binary ion exchange reactions. The model is based on the thermodynamic framework for adsorption exchange reactions developed by Gaines and Thomas (1953. Journal of Chemical Physics, 21, 714–718). The Wilson activity coefficient model is used for the adsorbed phase and

Socrates Ioannidis; Andrzej Anderko; Stephen J Sanders

2000-01-01

124

Catalysis using hydrous metal oxide ion exchangers  

DOEpatents

In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

Dosch, R.G.; Stephens, H.P.; Stohl, F.V.

1983-07-21

125

Catalysis using hydrous metal oxide ion exchanges  

DOEpatents

In a process which is catalyzed by a catalyst comprising an active metal on a carrier, said metal being active as a catalyst for the process, an improvement is provided wherein the catalyst is a hydrous, alkali metal or alkaline earth metal titanate, zirconate, niobate or tantalate wherein alkali or alkaline earth metal cations have been exchanged with a catalytically effective amount of cations of said metal.

Dosch, Robert G. (Albuquerque, NM); Stephens, Howard P. (Albuquerque, NM); Stohl, Frances V. (Albuquerque, NM)

1985-01-01

126

Ion-exchanged Tm3+:glass channel waveguide laser.  

PubMed

Continuous wave laser action around 1.9 ?m has been demonstrated in a Tm(3+)-doped germanate glass channel waveguide laser fabricated by ion-exchange. Laser action was observed with an absorbed power threshold of only 44 mW and a slope efficiency of up to 6.8% was achieved. Propagation loss at the lasing wavelength was measured to be 0.3 dB/cm. We believe this to be the first ion-exchanged Tm(3+)-doped glass waveguide laser. PMID:23546272

Choudhary, Amol; Kannan, Pradeesh; Mackenzie, Jacob I; Feng, Xian; Shepherd, David P

2013-04-01

127

Second-order schedules of token reinforcement with pigeons: effects of fixed- and variable-ratio exchange schedules.  

PubMed

Pigeons' key pecks produced food under second-order schedules of token reinforcement, with light-emitting diodes serving as token reinforcers. In Experiment 1, tokens were earned according to a fixed-ratio 50 schedule and were exchanged for food according to either fixed-ratio or variable-ratio exchange schedules, with schedule type varied across conditions. In Experiment 2, schedule type was varied within sessions using a multiple schedule. In one component, tokens were earned according to a fixed-ratio 50 schedule and exchanged according to a variable-ratio schedule. In the other component, tokens were earned according to a variable-ratio 50 schedule and exchanged according to a fixed-ratio schedule. In both experiments, the number of responses per exchange was varied parametrically across conditions, ranging from 50 to 400 responses. Response rates decreased systematically with increases in the fixed-ratio exchange schedules, but were much less affected by changes in the variable-ratio exchange schedules. Response rates were consistently higher under variable-ratio exchange schedules than tinder comparable fixed-ratio exchange schedules, especially at higher exchange ratios. These response-rate differences were due both to greater pre-ratio pausing and to lower local rates tinder the fixed-ratio exchange schedules. Local response rates increased with proximity to food under the higher fixed-ratio exchange schedules, indicative of discriminative control by the tokens. PMID:11599637

Foster, T A; Hackenberg, T D; Vaidya, M

2001-09-01

128

Second-order schedules of token reinforcement with pigeons: effects of fixed- and variable-ratio exchange schedules.  

PubMed Central

Pigeons' key pecks produced food under second-order schedules of token reinforcement, with light-emitting diodes serving as token reinforcers. In Experiment 1, tokens were earned according to a fixed-ratio 50 schedule and were exchanged for food according to either fixed-ratio or variable-ratio exchange schedules, with schedule type varied across conditions. In Experiment 2, schedule type was varied within sessions using a multiple schedule. In one component, tokens were earned according to a fixed-ratio 50 schedule and exchanged according to a variable-ratio schedule. In the other component, tokens were earned according to a variable-ratio 50 schedule and exchanged according to a fixed-ratio schedule. In both experiments, the number of responses per exchange was varied parametrically across conditions, ranging from 50 to 400 responses. Response rates decreased systematically with increases in the fixed-ratio exchange schedules, but were much less affected by changes in the variable-ratio exchange schedules. Response rates were consistently higher under variable-ratio exchange schedules than tinder comparable fixed-ratio exchange schedules, especially at higher exchange ratios. These response-rate differences were due both to greater pre-ratio pausing and to lower local rates tinder the fixed-ratio exchange schedules. Local response rates increased with proximity to food under the higher fixed-ratio exchange schedules, indicative of discriminative control by the tokens. PMID:11599637

Foster, T A; Hackenberg, T D; Vaidya, M

2001-01-01

129

The temperature dependence of ion exchanger sorption capacity in the glycine-nickel nitrate-ANKB-35 ion exchanger system from 298 to 338 K  

NASA Astrophysics Data System (ADS)

The complex formation and ion exchange processes in the glycine-nickel(II) ion-ANKB-35 polyampholyte system were studied. The composition of complex ions sorbed by the ion exchanger was determined, and the equilibrium characteristics of their sorption at different temperatures were calculated.

Astapov, A. V.; Peregudov, Yu. S.; Enyutina, M. V.

2009-06-01

130

Ion exchange studies on zinc-rich waste liquors  

Microsoft Academic Search

This paper reports on the use of ion exchange resins for the recovery of zinc, in a relatively pure form, from a zinc-rich industrial waste liquor and from model zinc-rich solutions. Lewatit OC-1026 resin was found to have good zinc selectivity, whilst the chelating resins Purolite S-930, Metalfix Chelamine and Metalfix Chelosolve showed greater selectivity for the major contaminant ions,

C Simpson; S. H Laurie

1999-01-01

131

Transport limitations in ion exchange membranes at low salt concentrations  

Microsoft Academic Search

In this work we show that the electrical resistance of ion exchange membranes strongly depends on the solution concentration: especially at low solution concentrations (<0.1M NaCl) we observe a very strong increase in electrical resistance of the membrane with decreasing concentration. To understand and clarify this behavior we systematically investigate the influence of the solution concentration on ion transport phenomena

Piotr D?ugo??cki; Benoīt Anet; Sybrand J. Metz; Kitty Nijmeijer; Matthias Wessling

2010-01-01

132

Specific ion effects on membrane potential and the permselectivity of ion exchange membranes.  

PubMed

Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The charge density and polarizability of the co-ions also appeared to influence permselectivity leading to ion-specific effects; co-ions that are charge dense and have low polarizability tended to result in high membrane permselectivity. PMID:25198913

Geise, Geoffrey M; Cassady, Harrison J; Paul, Donald R; Logan, Bruce E; Hickner, Michael A

2014-10-21

133

21 CFR 173.20 - Ion-exchange membranes.  

...ion-exchange membrane is prepared by subjecting a polyethylene base conforming to § 177.1520 of this chapter to polymerization with styrene until the polystyrene phase of the base is not less than 16 percent nor more than 30 percent by weight. The base is...

2014-04-01

134

Transport of drugs across porous ion exchange membranes  

Microsoft Academic Search

Porous ion exchange membranes have potential applications for drug delivery systems. Permeability of these membranes can be controlled by environmental factors like pH and ionic strength but also the drug properties have an important role in the permeation process. In this paper the influence of the drug charge, lipophilicity and molecular weight on the diffusional drug flux is demonstrated. The

S Åkerman; P Viinikka; B Svarfvar; K Järvinen; K Kontturi; J Näsman; A Urtti; P Paronen

1998-01-01

135

Ion exchange for the removal of natural organic matter  

Microsoft Academic Search

Because of their aliphatic and carboxylic acid structures, the polar components of natural organic matter (NOM), both charged and neutral, can give high yields of disinfection by-products (DBPs). For removal of charged organic species, ion exchange is better performing than coagulation with inorganic salts such as alum, as it very efficiently removes essentially all of the charged material, while alum

Brian Bolto; David Dixon; Robert Eldridge

2004-01-01

136

Separation of some lanthanides on potassium zinc hexacyanoferrate ion exchanger  

Microsoft Academic Search

Adsorption behaviour of Sm3+, Gd3+, Tb3+ and Tm3+ on potassium zinc hexacyanoferrate (PZF) was investigated. The effect of K+ and Zn2+ concentrations on the distribution coefficient was studied. The mechanism of ion exchange and possible separation of the lanthanides used are discussed.

N. Botros; S. El-Bayoumy; M. El-Garhy; S. A. Marei

1991-01-01

137

Separation of Lanthanides and Trivalent Actinides with Pressurized Ion Exchange  

Microsoft Academic Search

Certainly, one of the first triumphs of ion exchange chromatography was the separation and identification of fission product rare earths in the Manhattan Project in the early 1940s. Publications describing this work were withheld until 1947 when nine papers from the Oak Ridge National Laboratory and the Ames Laboratory at Iowa State University appeared simultaneously in the Journal of the

D. O. Campbell

1976-01-01

138

EVALUATING ION EXCHANGE FOR REMOVING RADIUM FROM GROUNDWATER  

EPA Science Inventory

This article focuses on the results of bench and pilot-scale studies of ion exchange processes for radium removal from groundwater in Lemont, Ill. atch and column studies indicated a very high resin selectivity for radium compared with common cations. xhaustion-regeneration studi...

139

EVALUATING ION EXCHANGE FOR REMOVING RADIUM FROM GROUNDWATER  

EPA Science Inventory

This article, the second in a series, focuses on the results of bench- and pilot-scale studies of ion exchange processes for radium removal from groundwater in Lemont, Ill. Batch and column studies indicated a very high resin selectivity for radium compared with common cations. E...

140

SELENIUM REMOVAL FROM DRINKING WATER BY ION EXCHANGE  

EPA Science Inventory

Strong-base anion exchangers were shown to remove selenate and selenite ions from drinking water. Because selenium species are usually present at low concentrations, the efficiency of removal is controlled by the concentration of the common drinking water anions, the most importa...

141

Magnetic ion exchange treatment of stabilized landfill leachate  

Microsoft Academic Search

Stabilized landfill leachate is characterized by a high concentration of non-biodegradable organic matter, which is similar in chemistry to dissolved organic matter (DOM) in the natural aquatic environment. Magnetic ion exchange (MIEX) resin treatment is well-studied in drinking water for removal of DOM from natural waters. There are fewer studies evaluating MIEX treatment of waste waters, and there is no

Treavor H. Boyer; Katherine C. Graf; Sarah E. H. Comstock; Timothy G. Townsend

2011-01-01

142

Ultra-high aspect ratio replaceable AFM tips using deformation-suppressed focused ion beam milling.  

PubMed

Fabrication of ultra-high aspect ratio exchangeable and customizable tips for atomic force microscopy (AFM) using lateral focused ion beam (FIB) milling is presented. While on-axis FIB milling does allow high aspect ratio (HAR) AFM tips to be defined, lateral milling gives far better flexibility in terms of defining the shape and size of the tip. Due to beam-induced deformation, it has so far not been possible to define HAR structures using lateral FIB milling. In this work we obtain aspect ratios of up to 45, with tip diameters down to 9 nm, by a deformation-suppressing writing strategy. Several FIB milling strategies for obtaining sharper tips are discussed. Finally, assembly of the HAR tips on a custom-designed probe as well as the first AFM scanning is shown. PMID:24149369

Savenko, Alexey; Yildiz, Izzet; Petersen, Dirch Hjorth; Bųggild, Peter; Bartenwerfer, Malte; Krohs, Florian; Oliva, Maria; Harzendorf, Torsten

2013-11-22

143

Separation of americium from curium by oxidation and ion exchange.  

PubMed

Nuclear energy has the potential to be a clean alternative to fossil fuels, but in order for it to play a major role in the US, many questions about the back end of the fuel cycle must be addressed. One of these questions is the difficult separation of americium from curium. Here, we report the oxidation of Am in two systems, perchloric acid and nitric acid and the affect of changing the acid has on the oxidation. K(d) values were observed and a direct separation factor was calculated and was seen to be as high as 20 for four metal(IV) pillared phosphate phosphonate inorganic organic hybrid ion exchange materials. These ion exchangers are characterized by very low selectivity for cations with low charge but extremely high uptake of ions of high charge. PMID:22827724

Burns, Jonathan D; Shehee, Thomas C; Clearfield, Abraham; Hobbs, David T

2012-08-21

144

Investigating the Use of Ion Exchange Resins for Processing Biodiesel Feedstocks  

E-print Network

Ion exchange resins, commonly used in water treatment, demonstrate promise for the production of biodiesel from biomass feedstocks. The goal of this presented PhD research is to investigate novel uses of ion exchange resins for processing biodiesel...

Jamal, Yousuf 1973-

2012-11-27

145

Development of high-aspect-ratio microchannel heat exchanger based on multi-tool milling process  

Microsoft Academic Search

A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters\\u000a were stacked together for simultaneously machining several high-aspect-ratio microchannels with manifold structures. On the\\u000a basis of multi-tool milling process, the structural design of the manifold side height, microchannel length, width, number,\\u000a and interval were analyzed. The heat transfer performances of high-aspect-ratio microchannel heat exchangers with

Min-qiang Pan; Jin-heng Li; Yong Tang

2008-01-01

146

Potentiometric sensors with ion-exchange Donnan exclusion membranes.  

PubMed

Potentiometric sensors that exhibit a non-Hofmeister selectivity sequence are normally designed by selective chemical recognition elements in the membrane. In other situations, when used as detectors in separation science, for example, membranes that respond equally to most ions are preferred. With so-called liquid membranes, a low selectivity is difficult to accomplish since these membranes are intrinsically responsive to lipophilic species. Instead, the high solubility of sample lipids in an ionophore-free sensing matrix results in a deterioration of the response. We explore here potentiometric sensors on the basis of ion-exchange membranes commonly used in fuel cell applications and electrodialysis, which have so far not found their way into the field of ion-selective electrodes. These membranes act as Donnan exclusion membranes as the ions are not stripped of their hydration shell as they interact with the membrane. Because of this, lipophilic ions are no longer preferred over hydrophilic ones, making them promising candidates for the detection of abundant ions in the presence of lipophilic ones or as detectors in separation science. Two types of cation-exchanger membranes and one anion-exchange membrane were characterized, and potentiometric measuring ranges were found to be Nernstian over a wide range down to about 10 ?M concentrations. Depending on the specific membrane, lipophilic ions gave equal response to hydrophilic ones or were even somewhat discriminated. The medium and long-term stability and reproducibility of the electrode signals were found to be promising when evaluated in synthetic and whole blood samples. PMID:23731350

Grygolowicz-Pawlak, Ewa; Crespo, Gastón A; Ghahraman Afshar, Majid; Mistlberger, Günter; Bakker, Eric

2013-07-01

147

Ion-Exchange Characteristics of a Layered Metal Sulfide for Removal of Sr From Aqueous Solutions  

Microsoft Academic Search

Strontium-90 (Sr) is the most abundant radionuclide in radioactive wastes, and is typically isolated by treatment with an inorganic ion-exchange material. Most inorganic ion-exchange materials contain oxygen. The ion-exchange chemistry of layered metal sulfides is relatively poorly explored compared with that of oxide ion-exchange materials. Here, a layered metal sulfide (UCR-28), constructed from [ZnGe3S9(H2O)] supertetrahedral clusters, was prepared under hydrothermal

Xingliang Li; Bijun Liu; Yuan Jian; Wenbin Zhong; Wanjun Mu; Jiaheng He; Zongping Ma; Guoping Liu; Shunzhong Luo

2012-01-01

148

Membrane consisting of polyquaternary amine ion exchange polymer network interpenetrating the chains of thermoplastic matrix polymer  

NASA Technical Reports Server (NTRS)

An ion exchange membrane was formed from a solution containing dissolved matrix polymer and a set of monomers which are capable of reacting to form a polyquaternary ion exchange material; for example vinyl pyride and a dihalo hydrocarbon. After casting solution and evaporation of the volatile component's, a relatively strong ion exchange membrane was obtained which is capable of removing anions, such as nitrate or chromate from water. The ion exchange polymer forms an interpenetrating network with the chains of the matrix polymer.

Rembaum, A.; Wallace, C. J. (inventors)

1978-01-01

149

Preparation of ion exchanger layered electrodes for advanced membrane capacitive deionization (MCDI)  

Microsoft Academic Search

A noble electrode for capacitive deionization (CDI) was prepared by embedding ion exchanger onto the surface of a carbon electrode to practice membrane capacitive deionization (MCDI). Bromomethylated poly (2, 6-dimethyl-1, 4-phenylene oxide) (BPPO) was sprayed on carbon cloth followed by sulfonation and amination to form cation exchange and anion exchange layers, respectively. The ion exchange layers were examined by Scanning

Ju-Young Lee; Seok-Jun Seo; Sung-Hyun Yun; Seung-Hyeon Moon

2011-01-01

150

Ion exchange using poorly activated supports, an easy way for purification of large proteins  

Microsoft Academic Search

Ion-exchange chromatography using commercial ionic supports is a commonly used technique for protein purification. However, selective adsorption of a target protein from a given extract onto commercial ion exchangers seems to be quite complex since they are designed to adsorb the maximum percentage of proteins with the opposite charge. In this paper, ion-exchanger supports with different activation degrees (from 1

Benevides C. C. Pessela; Roberto Munilla; Lorena Betancor; Manuel Fuentes; Alfonso V. Carrascosa; Alejandro Vian; Roberto Fernandez-Lafuente; Jose M. Guisįn

2004-01-01

151

Innovative uses of specialy ion exchange resins provide new cost-effective options for metals removal  

Microsoft Academic Search

Ion exchange treatment of water for boiler and process systems is a documented, proven unit operation. The recent development of a group of novel resins had expanded the potential use of ion exchange processes to a new range of applications. By applying a different functional group onto the traditional styrene\\/divinylbenzene polymer backbone, ion exchange technology becomes a cost-effective treatment option

George Totura

1996-01-01

152

RECENT ADVANCES IN ION EXCHANGE MATERIALS AND PROCESSES FOR POLLUTION PREVENTION  

EPA Science Inventory

The goal of this article was to summarize the recent advances in ion exchange technology for the metal finishing industry. Even though the ion exchange technology is mature and is widely employed in the industry, new applications, approaches and ion exchange materials are emergi...

153

Radon (222Rn) in ground water of fractured rocks: A diffusion/ion exchange model  

USGS Publications Warehouse

Ground waters from fractured igneous and high-grade sialic metamorphic rocks frequently have elevated activity of dissolved radon (222Rn). A chemically based model is proposed whereby radium (226Ra) from the decay of uranium (238U) diffuses through the primary porosity of the rock to the water-transmitting fracture where it is sorbed on weathering products. Sorption of 226Ra on the fracture surface maintains an activity gradient in the rock matrix, ensuring a continuous supply of 226Ra to fracture surfaces. As a result of the relatively long half-life of 226Ra (1601 years), significant activity can accumulate on fracture surfaces. The proximity of this sorbed 226Ra to the active ground water flow system allows its decay progeny 222Rn to enter directly into the water. Laboratory analyses of primary porosity and diffusion coefficients of the rock matrix, radon emanation, and ion exchange at fracture surfaces are consistent with the requirements of a diffusion/ion- exchange model. A dipole-brine injection/withdrawal experiment conducted between bedrock boreholes in the high-grade metamorphic and granite rocks at the Hubbard Brook Experimental Forest, Grafton County, New Hampshire, United States (42??56???N, 71??43???W) shows a large activity of 226Ra exchanged from fracture surfaces by a magnesium brine. The 226Ra activity removed by the exchange process is 34 times greater than that of 238U activity. These observations are consistent with the diffusion/ion-exchange model. Elutriate isotopic ratios of 223Ra/226Ra and 238U/226Ra are also consistent with the proposed chemically based diffusion/ion-exchange model.

Wood, W. W.; Kraemer, T. F.; Shapiro, A.

2004-01-01

154

Effect of the steric accessibility of the exchange site in long-chain quaternary ammonium salts on the anion-exchange extraction of divalent ions  

Microsoft Academic Search

The constants of anion-exchange extraction of divalent ions by quaternary ammonium salts of various structures were determined.\\u000a The exchange constants depend significantly on steric accessibility of the exchange site. For the exchange of small-size anions,\\u000a the affinity of the ion exchanger for divalent ions is higher than for monovalent ions. For large divalent anions, the exchange\\u000a constant may increase or

V. V. Egorov; E. M. Rakhman’ko; E. V. Pomelenok; E. B. Okaev

2006-01-01

155

The influence of the natures of the solvent and coion on the properties of ion-exchange systems  

NASA Astrophysics Data System (ADS)

The influence of the coion and the ratio between the water-acetone binary solvent components on cation and anion exchange on sulfo-and aminostyrene ion exchangers with a medium degree of cross-linking were studied. The dependence of selectivity coefficients on the degree of ionite filling by the desired component was found to vary substantially as the composition of the solvent and the radius of the cation changed.

Mechkovskii, S. A.; Sankevich, N. A.; Trifonova, A. N.

2008-08-01

156

Switch to an advanced ion exchange resin cuts boiler costs  

SciTech Connect

This article discusses how a field study demonstrated how that one refinery could save $384,000/yr by changing boiler feedwater ion exchange resin. Constant deterioration of ion exchange resin, used to demineralize boiler feedwater, prompted Star Enterprise to conduct a side-by-side evaluation of two resins. The study compared the macroporous weak base anion (WBA) resin that the refinery had used for years with a new WBA resin that features a uniform particle size. The results of this field trial, which was conducted over an 18-month period, showed that the uniform particle size resin had a higher resistance to organic fouling and produced an average of 28 percent more treated water per cycle than the old resin. Replacement and regeneration costs with the new resin resulted in a $48,000 annual savings per bed of resin.

Kratzer, W.R.; Coker, S.D.

1994-10-01

157

Diverse secondary interactions between ions exchanged into the resin phase and their analytical applications.  

PubMed

The research activities by the author's group to elucidate the chemical states of ions within the ion exchange resin phase are summarized. The resin with the higher exchange capacity has the smaller space available for ion exchange, and the higher cross linking degree interferes more with swelling of the resin. As a result, diverse secondary interactions between exchanged ions are observed on the resins of high exchange capacities and high cross linking degrees: the van der Waals contact results in incomplete exchange or enhanced dehydration of ions, hydrogen bond formation between acidic anions, and coadsorption of anions with metal ions. Contribution of the simple ion exchange mechanism to the reactions of iminodiactate-type chelating resins with metal ions in the acidic media is quantitatively discussed. The resulting complexes were successfully applied to preconcentration and separation of anions. PMID:24420244

Yuchi, Akio

2014-01-01

158

Ammonium removal from digested sludge liquors using ion exchange  

Microsoft Academic Search

Liquors arising from the dewatering of digested sludge typically contain ammonium levels in the range 200–700mgl?1 NH4+-N. These liquors are frequently recycled to the head of the wastewater treatment works (WwTW) untreated and can constitute >25% of the total nitrogen load entering the works at inlet. This paper investigates the use of a clay-based material, MesoLite, as an ion exchange

A. Thornton; P. Pearce; S. A. Parsons

2007-01-01

159

Selective separation of vanadium from molybdenum by electrochemical ion exchange  

Microsoft Academic Search

This paper presents the results of work on the selective electrochemical elution of vanadium co-adsorbed with molybdenum on Amberlite IRA 94S resin. A three-compartment cell equipped with an RVC (Reticulated Vitreous Carbon) cathode mixed with ion exchange resin and two Ti–Pt anodes separated by a Daramic diaphragm was used. In the process, the pentavalent vanadyl anion is selectively desorbed with

P Henry; A Van Lierde

1998-01-01

160

Ammonia Removal from Saline Wastewater by Ion Exchange  

Microsoft Academic Search

Ion exchange materials that are highly selective for ammonia have been used for wastewater treatment but they are mainly suitable\\u000a for use in non-saline water. In this paper, some new materials have been evaluated for the selective uptake of ammonia from\\u000a saline wastewater. Those materials include: MN 500 (belongs to the group of material known as Macronets which are hypercrosslinked

N. Miladinovic; L. R. Weatherley; J. L. López-Ruiz

2004-01-01

161

Radiation degradation in EPICOR-2 ion exchange resins  

Microsoft Academic Search

The Low-Level Waste Data base Development -- EPICOR-II Resin\\/Liner Investigation Program funded by the US Nuclear Regulatory Commission is investigating chemical and physical conditions for organic ion exchange resins contained in several EPICOR-II prefilters. Those prefilters were used during cleanup of contaminated water from the Three Mile Island Nuclear Power Station after the March 1979 accident. The work was performed

J. W. Jr. McConnell; D. A. Johnson; R. D. Sr. Sanders

1990-01-01

162

Momentum transfer in relativistic heavy ion charge-exchange reactions  

NASA Astrophysics Data System (ADS)

Relativistic heavy ion charge-exchange reactions yield fragments (Delta-Z = + 1) whose longitudinal momentum distributions are downshifted by larger values than those associated with the remaining fragments (Delta-Z = 1, -2,...). Kinematics alone cannot account for the observed downshifts; therefore, an additional contribution from collision dynamics must be included. In this work, an optical model description of collision momentum transfer is used to estimate the additional dynamical momentum downshift. Good agreement between theoretical estimates and experimental data is obtained.

Townsend, L. W.; Wilson, J. W.; Khan, F.; Khandelwal, G. S.

1991-07-01

163

Momentum transfer in relativistic heavy ion charge-exchange reactions.  

PubMed

Relativistic heavy ion charge-exchange reactions yield fragments (delta Z = +1) whose longitudinal momentum distributions are downshifted by larger values than those associated with the remaining fragments (delta Z = -1, -2, ...). Kinematics alone cannot account for the observed downshifts; therefore, an additional contribution from collision dynamics must be included. In this work, an optical model description of collision momentum transfer is used to estimate the additional dynamical momentum downshift. Good agreement between theoretical estimates and experimental data is obtained. PMID:9967432

Townsend, L W; Wilson, J W; Khan, F; Khandelwal, G S

1991-07-01

164

Integrated optic broadband duplexer made by ion exchange  

NASA Astrophysics Data System (ADS)

The development of optical amplification and bidirectional traffic in local and wide area networks requires broadband multiplexers which are able to treat the signal of an entire telecommunication window. A device made by ion exchange and answering to these needs is proposed in this letter. Its working principle, based on a leaky structure is first explained. An experimental result confirming a good broadband spectral behavior is then presented. Its spectral response displays two duplexing bands of at least 100 nm.

Ghibaudo, E.; Broquin, J.-E.; Benech, P.

2003-02-01

165

Raman microspectroscopy investigation of Ag ion-exchanged glass layers.  

PubMed

The ion-exchange process is widely used to dope silicate glass layers with silver, aimed at controlling the Ag state in view of possible applications, ranging from light waveguide fabrication to nanostructured composite glass synthesis. The silver doped glass structure as well as its prescribed properties depend on both the preparation parameters and the subsequent treatments. Several structural aspects are still open with regard either to the modification of the glass incorporating the dopant, or to clustering phenomena silver undergoes as a function of its local concentration and state, which are in turn strongly dependent on the preparation route. Systematic characterizations of these systems are mandatory to address the role of the various synthesis parameters in giving rise to the observed features, thus pointing out the effective methodologies for the fabrication of silicate glass layers with the desired properties. In this work, the results of micro-Raman, optical absorption and photoluminescence characterizations are presented for soda-lime glass slides doped with silver by Ag(+)-Na+ exchange and subsequent thermal treatments in air. In particular, a cross-section profiling analysis by Raman micro-spectroscopy was performed on Ag ion-exchanged samples after treatment at some different temperatures. The experimental findings allow to elucidate the role of the treatment temperature in the clustering process related to the local Ag concentration inside the exchanged glass layer. PMID:23421246

Rahman, A; Giarola, M; Cattaruzza, E; Gonella, F; Mardegan, M; Trave, E; Quaranta, A; Mariotto, G

2012-11-01

166

X-Ray emission following low-energy charge exchange collisions of highly charged ions  

PubMed

K-shell x-ray emission following low-energy charge exchange collisions ( ions up to U91+. The data resolve capture into angular momentum states with l = 1 and provide a stringent test of theory. The assumption of Stark mixing of angular momentum states is inappropriate at such energies. Results from detailed calculations give a better description of the data, but significant discrepancies are noted. The measurements show that the hardness ratio of charge-exchange induced K-shell x-ray emission represents a diagnostic of the dynamics of ion-atom interactions in situations where the energy is below 1 keV/amu, e.g., in solar wind collisions. PMID:11102193

Beiersdorfer; Olson; Brown; Chen; Harris; Neill; Schweikhard; Utter; Widmann

2000-12-11

167

Thermal analysis for ion-exchange column system  

SciTech Connect

Models have been developed to simulate the thermal characteristics of Crystalline Silico-titanate (CST) ion exchange media fully loaded with radioactive cesium in a column configuration and distributed within a waste storage tank. This work was conducted to support the Small Column Ion Exchange (SCIX) program which is focused on processing dissolved, high-sodium salt waste for the removal of specific radionuclides (including Cs-137, Sr-90, and actinides) within a High Level Waste (HLW) storage tank at the Savannah River Site. A two-dimensional computational modeling approach for the in-column ion-exchange domain was taken to include conservative, bounding estimates for key parameters such that the results would provide the maximum centerline temperatures achievable under the design configurations using a feed composition known to promote high cesium loading on CST. A primary objective of these calculations was to estimate temperature distributions across packed CST beds immersed in waste supernate or filled with dry air under various accident scenarios. Accident scenarios evaluated included loss of salt solution flow through the bed, inadvertent column drainage, and loss of active cooling in the column. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature. (authors)

Lee, S. Y.; King, W. D. [Savannah River National Laboratory, Savannah River Site, Aiken, SC 29808 (United States)

2012-07-01

168

Ion exchange extraction of heavy metals from wastewater sludges.  

PubMed

Heavy metals are common contaminants of some industrial wastewater. They find their way to municipal wastewaters due to industrial discharges into the sewerage system or through household chemicals. The most common heavy metals found in wastewaters are lead, copper, nickel, cadmium, zinc, mercury, arsenic, and chromium. Such metals are toxic and pose serious threats to the environment and public health. In recent years, the ion exchange process has been increasingly used for the removal of heavy metals or the recovery of precious metals. It is a versatile separation process with the potential for broad applications in the water and wastewater treatment field. This article summarizes the results obtained from a laboratory study on the removal of heavy metals from municipal wastewater sludges obtained from Ardhiya plant in Kuwait. Data on heavy metal content of the wastewater and sludge samples collected from the plant are presented. The results obtained from laboratory experiments using a commercially available ion exchange resin to remove heavy metals from sludge were discussed. A technique was developed to solubilize such heavy metals from the sludge for subsequent treatment by the ion exchange process. The results showed high efficiency of extraction, almost 99.9%, of heavy metals in the concentration range bound in wastewater effluents and sludges. Selective removal of heavy metals from a contaminated wastewater/sludge combines the benefits of being economically prudent and providing the possibility of reuse/recycle of the treated wastewater effluents and sludges. PMID:15027828

Al-Enezi, G; Hamoda, M F; Fawzi, N

2004-01-01

169

Branching ratios in heavy ion reactions: Constrained phase space approach  

NASA Astrophysics Data System (ADS)

Branching ratios in heavy ion reactions can be quantitatively predicted using the procedure of maximal entropy subject to the constraints that determine the energy distribution. Including the two constraints required to quantitatively determine the energy distribution accounts very well for the branching fractions for all the reactions examined. The branching ratio amongst two ejectiles is given as the ratio of two nuclear partition functions. Including only the single dominant constraint on the energy distribution provides a near quantitative description of the branching ratios. In this latter case, the branching fractions can be computed directly from the optimal Q value. The exact procedure for doing so is described. An approximation to the order of magnitude of the branching fraction into a given exit channel is lnP=?(Qgg-), where ? is the temperature of the residual nucleus, Qgg is the ground-state to ground-state Q value, and is the mean value. In general, both ? and differ for different exit channels, less so, however, within a given family of isotopes. NUCLEAR REACTIONS Heavy ions, 232Th(16O, X), X=9,10Be, 11-13B, 12-15C, 15-17N, 18,19O, E=105 MeV at ?=70°, X=10Be, 11B, 12-14C, 15N, E=105 MeV at ?=50°, 60°, E=125 MeV at ?=50°, 60°. 232Th(15N, X), X=9,10Be, 11-13B, 12-15C, E=86 MeV at ?=60°, X=9-11Be, 11-13B, 12-15C, E=95 MeV at ?=70°. 181Ta(35Cl, X), X=30,31Si, 31-33P, 33-35S, 36,37Cl, E=205 MeV at ?=70°. 53Cr(14N, X), X=6,7Li, 7,9,10Be, 10-12B, 12,13C, E=90 MeV at ?=16°. Branching fractions and energy distribution of ejectiles. Maximal entropy subject to constraints. Nuclear partition functions.

Engel, Y. M.; Levine, R. D.

1983-12-01

170

Negative Joule Heating in Ion-Exchange Membranes  

E-print Network

In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides the positive Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, there is also negative Joule heating in one of the EDLs. We define Joule heating as the inner product of the two vectors current and field strength. Also when fluid flows through a charged membrane, at one side of the membrane there is pressure-related cooling, due to the osmotic and hydrostatic pressure differences across the EDLs.

P. M. Biesheuvel; D. Brogioli; H. V. M. Hamelers

2014-02-06

171

Negative Joule Heating in Ion-Exchange Membranes  

E-print Network

In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides the positive Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, there is also negative Joule heating in one of the EDLs. We define Joule heating as the inner product of the two vectors current and field strength. Also when fluid flows through a charged membrane, at one side of the membrane there is pressure-related cooling, due to the osmotic and hydrostatic pressure differences across the EDLs.

Biesheuvel, P M; Hamelers, H V M

2014-01-01

172

Time-cycled inverse ratio ventilation does not improve gas exchange during anaesthesia  

Microsoft Academic Search

Inverse ratio ventilation (IRV) has been reported to improve oxygenation at lower peak airway pressures in patients with respiratory\\u000a failure. Therefore we hypothesised that IRV might also improve oxygen exchange during anaesthesia. Conventional ratio ventilation\\u000a (CRV) and IRV were compared in 24 low-risk surgical patients who were paralysed and whose lungs were ventilated with air\\/02 by a non-rebreathing circuit and

W. A. Tweed; T. L. Lee

1991-01-01

173

The effect of silver ions and nanoparticles on the properties of ion-exchange materials  

Microsoft Academic Search

The effect of silver ions and nanoparticles on the electrochemical properties of KU-2-8 sulfocationite, MF-4SK homogeneous\\u000a sulfocationite membrane, and MA-40 heterogeneous anion-exchange membrane is studied. Using scanning electron microscopy, the\\u000a particle distribution throughout the cationexchanger thickness is studied. The method of IR spectroscopy is used for studying\\u000a the interaction of silver nanoparticles and ions and also of Cu2+ and Ni2+

N. V. Shel’deshov; S. S. Mel’nikov; T. T. Solov’eva; A. V. Bespalov; V. F. Levchenko; V. D. Buikliskii; V. I. Zabolotskii

2011-01-01

174

High-capacity cation-exchange column for enhanced resolution of adjacent peaks of cations in ion chromatography.  

PubMed

One of the advantages of ion chromatography [Anal Chem. 47 (1975) 1801] as compared to other analytical techniques is that several ions may be analyzed simultaneously. One of the most important contributions of cation-exchange chromatography is its sensitivity to ammonium ion, which is difficult to analyze by other techniques [J. Weiss, in: E.L. Johnson (Ed.), Handbook of Ion Chromatography, Dionex, Sunnyvale, CA, USA]. The determination of low concentrations of ammonium ion in the presence of high concentrations of sodium poses a challenge in cation-exchange chromatography [J. Weiss, Ion Chromatography, VCH, 2nd Edition, Weinheim, 1995], as both cations have similar selectivities for the common stationary phases containing either sulfonate or carboxylate functional groups. The task was to develop a new cation-exchange stationary phase (for diverse concentration ratios of adjacent peaks) to overcome limitations experienced in previous trails. Various cation-exchange capacities and column body formats were investigated to optimize this application and others. The advantages and disadvantages of two carboxylic acid columns of different cation-exchange capacities and different column formats will be discussed. PMID:11453025

Rey, M A

2001-06-22

175

Truly incomplete and complex exchanges in prematurely condensed chromosomes of human fibroblasts exposed in vitro to energetic heavy ions  

NASA Technical Reports Server (NTRS)

Confluent human fibroblast cells (AG1522) were irradiated with gamma rays, 490 MeV/nucleon silicon ions, or iron ions at either 200 or 500 MeV/nucleon. The cells were allowed to repair at 37 degrees C for 24 h after exposure, and a chemically induced premature chromosome condensation (PCC) technique was used to condense chromosomes in the G2 phase of the cell cycle. Incomplete and complex exchanges were analyzed in the irradiated samples. To verify that chromosomal breaks were truly unrejoined, chromosome aberrations were analyzed using a combination of whole-chromosome specific probes and probes specific for the telomere region of the chromosome. Results showed that the frequency of unrejoined chromosome breaks was higher after irradiation with the heavy ions of high LET, and consequently the ratio of incomplete to complete exchanges increased steadily with LET up to 440 keV/microm, the highest LET included in the present study. For samples exposed to 200 MeV/nucleon iron ions, chromosome aberrations were analyzed using the multicolor FISH (mFISH) technique, which allows identification of both complex and truly incomplete exchanges. Results of the mFISH study showed that 0.7 and 3 Gy iron ions produced similar ratios of complex to simple exchanges and incomplete to complete exchanges; these ratios were higher than those obtained after exposure to 6 Gy gamma rays. After 0.7 Gy of iron ions, most complex aberrations were found to involve three or four chromosomes, which is a likely indication of the maximum number of chromosome domains traversed by a single iron-ion track.

Wu, Honglu; Durante, Marco; Furusawa, Yoshiya; George, Kerry; Kawata, Tetsuya; Cucinotta, Francis A.

2003-01-01

176

Preventing fouling of ion-exchange resins - II  

SciTech Connect

Reports on agents that can reduce the efficiency of ion-exchange resins, together with some simple field tests used to confirm fouling. The problem of fouling by oily or greasy materials is encountered almost exclusively in cation resins. Treatment with a nonionic surfactant-based alkaline cleaner is the most effective approach to the removal of oily and greasy foulants. Cation resins can be treated in an offline cleanup or by maintenance feed to the backwash water. The major problem associated with silt or clay fouling is the impedance to water flow caused, and the resulting channeling of impurities through the bed. Surfactant/alkaline cleaners are highly effective in removing silt and clay from the bed. Other topics covered include colloidal silica fouling, testing for ''organic'' fouling, and a field test to confirm iron fouling. Concludes that the increased use of ion-exchange equipment and boiler-water treatment programs formulated for use with ''pretreated'' water has heightened the need for ionexchangers to operate as effectively as possible. Fouling of ionexchange resin by metal oxides, salts, oil, silt, silica and various organic compounds can result in a reduction of exchange efficiency. Proper selection of cleaning programs can restore much of this lost efficiency. The implementation of chemical maintenance programs can often avert the recurrence of fouling and assure good water quality.

Pelosi, P.; McCarthy, J.

1982-09-01

177

Origin of Selectivity in Tunnel Type Inorganic Ion Exchangers  

SciTech Connect

The removal of highly radioactive species 137Cs and 90Sr from Weapon's Grade Tank Waste is a daunting task. The tanks normally are 5-7M in Na+, 1-3M in NaOH but only {approx}10-5M in the targeted species. Nevertheless several sorbents and ion exchangers have been found that are sufficiently selective to be considered for remediation purposes. We are involved in a collaborative study, joint with personnel at the Westinghouse Research Center, Sandia National Laboratory and University of Notre Dame to uncover the origins of this selectivity in these compounds. The presentation will be concerned with the framework of titanium silicates with the sitinikite and pharmacosiderite structures. Both compounds have been synthesized as pure titanium silicates or as Nb and Ge substituted forms. Their structures in the sodium and proton forms as well as the Cs+ and Sr2+ ion forms will be described together with insight into the exchange mechanism as determined by in situ X-ray studies of Cs+ exchange utilizing synchrotron radiation.

Clearfield, Abraham; Tripathi, Akhilesh; Medvedev, Dmitri; Delgado, Jose; Nyman, May

2004-03-29

178

Selective removal of fluoride ions by a two-way ion-exchange cyclic process  

Microsoft Academic Search

The demand for the new development of specific separation techniques for the treatment of drinking water leads to re-examining the use of cyclic operations in ion exchange processes. Establishing stable limit fronts inside the column is the required condition to allow the use of two-way chromatography methods and insure the process efficiency. This paper presents numerical simulations and experimental validation

C. Castel; M. Schweizer; M. O. Simonnot; M. Sardin

2000-01-01

179

Equilibrium of uranium(VI) ion exchange of nitrogen-and phosphorus-containing polyampholytes in fluorine-containing solutions  

Microsoft Academic Search

The authors investigate equilibrium of uranium ion exchange in hydrofluoric acid and ammonium fluoride solutions. They show that HF and NHāF concentrations affect the uranium ion exchange equilibrium on polyampholytes containing nitrogen and phosporous. They prove that the uranium ion exchange equilibrium in fluorine-containing solutions on the referred ion exchangers can be described satisfactorily.

V. V. Maiorov; V. S. Pakholkov; V. N. Rychkov

1985-01-01

180

Equilibrium of uranium(VI) ion exchange of nitrogen-and phosphorus-containing polyampholytes in fluorine-containing solutions  

SciTech Connect

The authors investigate equilibrium of uranium ion exchange in hydrofluoric acid and ammonium fluoride solutions. They show that HF and NH/sub 4/F concentrations affect the uranium ion exchange equilibrium on polyampholytes containing nitrogen and phosporous. They prove that the uranium ion exchange equilibrium in fluorine-containing solutions on the referred ion exchangers can be described satisfactorily.

Maiorov, V.V.; Pakholkov, V.S.; Rychkov, V.N.

1985-07-01

181

Removal of THM precursors by coagulation or ion exchange.  

PubMed

The removal of natural organic matter (NOM) from drinking water supplies can be achieved by different processes, among them coagulation and adsorption. Synthetic waters made from concentrates of humic substances from reservoir and river waters were tested in the laboratory for ease of removAl of NOM by coagulation with cationic organic polymers and with alum, and by adsorption on anion exchangers. For polymers such as high molecular weight polydiallyldimethylammonium chloride (polyDADMAC) and cationic polyacrylamides of high charge, performance was nearly as effective as alum, with colour removals 86-100% of those obtained for alum. Ion exchange using the best commercially available resins designed for this purpose, a gel polystyrene and a macroporous acrylic resin, was more effective than alum treatment for two of the natural waters studied, but inferior for a third. The resins were overall superior to cationic polymers. The NOM was separated into four fractions based on hydrophobic and hydrophilic properties. Alum was not as effective as ion exchange for the elimination of individual ionic NOM fractions. It was better than cationic polymers for removal of humic and fulvic acids, although polyDADMAC was as good for one water. For the removal of charged compounds alum then polyDADMAC were the best performers for that water. Unequivocal evidence was obtained that coagulants remove material that is not adsorbed by resins, and vice versa. A combination of coagulation with a cationic polymer and adsorption by an anion exchanger removed essentially all of the NOM. The preference of the coagulants was for the larger, more hydrophobic molecules, and of resins for smaller highly charged hydrophilic molecules. Each fraction had trihalomethane formation potentials in the range 11-24 microg/mg, except for one water that was more reactive. Hence, the actual amount of each fraction in the original water becomes a crucial factor. PMID:12448555

Bolto, Brian; Dixon, David; Eldridge, Rob; King, Simon

2002-12-01

182

Dispersion attendant sodium/hydrogen ion exchange in reservoir sands  

SciTech Connect

Chromatographic lag observed upon injection of dilute alkali into reservoir sands is now well explained in terms of sodium/hydrogen ion exchange. However, the spread of the eluting hydroxide is more extreme than that associated with axial dispersion. The authors postulate an additional mass-transfer resistance caused by molecular diffusion in a microporous clay fraction. A quantitative model for this diffusion resistance is presented that compares favorably with experimental hydroxide histories from a water-saturated Berea sandstone. Both thin-section and scanning electron microscope (SEM) examination of the Berea rock confirm the presence of microporous regions of clay fines.

Jensen, J.A.; Gillis, J.V.; Radke, C.J.

1986-11-01

183

Calculation of stopping power ratios for carbon ion dosimetry.  

PubMed

Water-to-air stopping power ratio calculations for the ionization chamber dosimetry of clinical carbon ion beams with initial energies from 50 to 450 MeV/u have been performed using the Monte Carlo technique. To simulate the transport of a particle in water the computer code SHIELD-HIT v2 was used, which is a newly developed version where substantial modifications were implemented on its predecessor SHIELD-HIT v1 (Gudowska et al 2004 Phys. Med. Biol. 49 1933-58). The code was completely rewritten replacing formerly used single precision variables with double precision variables. The lowest particle transport specific energy was decreased from 1 MeV/u down to 10 keV/u by modifying the Bethe-Bloch formula, thus widening its range for medical dosimetry applications. In addition, the code includes optionally MSTAR and ICRU-73 stopping power data. The fragmentation model was verified and its parameters were also adjusted. The present code version shows excellent agreement with experimental data. It has been used to compute the physical quantities needed for the calculation of stopping power ratios, s(water,air), of carbon beams. Compared with the recommended constant value given in the IAEA Code of Practice, the differences found in the present investigations varied between 0.5% and 1% at the plateau region, respectively for 400 MeV/u and 50 MeV/u beams, and up to 2.3% in the vicinity of the Bragg peak for 50 MeV/u. PMID:16625042

Geithner, Oksana; Andreo, P; Sobolevsky, N; Hartmann, G; Jäkel, O

2006-05-01

184

Calculation of stopping power ratios for carbon ion dosimetry  

NASA Astrophysics Data System (ADS)

Water-to-air stopping power ratio calculations for the ionization chamber dosimetry of clinical carbon ion beams with initial energies from 50 to 450 MeV/u have been performed using the Monte Carlo technique. To simulate the transport of a particle in water the computer code SHIELD-HIT v2 was used, which is a newly developed version where substantial modifications were implemented on its predecessor SHIELD-HIT v1 (Gudowska et al 2004 Phys. Med. Biol. 49 1933-58). The code was completely rewritten replacing formerly used single precision variables with double precision variables. The lowest particle transport specific energy was decreased from 1 MeV/u down to 10 keV/u by modifying the Bethe-Bloch formula, thus widening its range for medical dosimetry applications. In addition, the code includes optionally MSTAR and ICRU-73 stopping power data. The fragmentation model was verified and its parameters were also adjusted. The present code version shows excellent agreement with experimental data. It has been used to compute the physical quantities needed for the calculation of stopping power ratios, swater,air, of carbon beams. Compared with the recommended constant value given in the IAEA Code of Practice, the differences found in the present investigations varied between 0.5% and 1% at the plateau region, respectively for 400 MeV/u and 50 MeV/u beams, and up to 2.3% in the vicinity of the Bragg peak for 50 MeV/u.

Geithner, Oksana; Andreo, P.; Sobolevsky, N.; Hartmann, G.; Jäkel, O.

2006-05-01

185

Enhanced gas-phase hydrogen-deuterium exchange of oligonucleotide and protein ions stored in an external multipole ion reservoir.  

PubMed

Rapid gas-phase hydrogen-deuterium (H-D) exchange from D(2)O and ND(3) into oligonucleotide and protein ions was achieved during storage in a hexapole ion reservoir. Deuterated gas is introduced through a capillary line that discharges directly into the low-pressure region of the reservoir. Following exchange, the degree of H-D exchange is determined using Fourier transform ion cyclotron resonance mass spectrometry. Gas-phase H-D exchange experiments can be conducted more than 100 times faster than observed using conventional in-cell exchange protocols that require lower gas pressures and additional pump-down periods. The short experimental times facilitate the quantitation of the number of labile hydrogens for less reactive proteins and structured oligonucleotides. For ubiquitin, we observe approximately 65 H-D exchanges after 20 s. Exchange rates of > 250 hydrogens s(-1) are observed for oligonucleotide ions when D(2)O or ND(3) is admitted directly into the external ion reservoir owing to the high local pressure in the hexapole. Partially deuterated oligonucleotide ions have been fragmented in the reservoir using infrared multiphoton dissociation (IRMPD). The resulting fragment ions show that exchange predominates at charged sites on the 5'- and 3'-ends of the oligonucleotide, whereas exchange is slower in the core. This hardware configuration is independent of the mass detector and should be compatible with other mass spectrometric platforms including quadrupole ion trap and time-of-flight mass spectrometers. PMID:10633235

Hofstadler, S A; Sannes-Lowery, K A; Griffey, R H

2000-01-01

186

Ion exchange separation of chromium from natural water matrix for stable isotope mass spectrometric analysis  

USGS Publications Warehouse

A method has been developed for separating the Cr dissolved in natural water from matrix elements and determination of its stable isotope ratios using solid-source thermal-ionization mass spectrometry (TIMS). The separation method takes advantage of the existence of the oxidized form of Cr as an oxyanion to separate it from interfering cations using anion-exchange chromatography, and of the reduced form of Cr as a positively charged ion to separate it from interfering anions such as sulfate. Subsequent processing of the separated sample eliminates residual organic material for application to a solid source filament. Ratios for 53Cr/52Cr for National Institute of Standards and Technology Standard Reference Material 979 can be measured using the silica gel-boric acid technique with a filament-to-filament standard deviation in the mean 53Cr/52Cr ratio for 50 replicates of 0.00005 or less. (C) 2000 Elsevier Science B.V. All rights reserved.

Ball, J.W.; Bassett, R.L.

2000-01-01

187

Electrically switched cesium ion exchange. FY 1996 annual report  

SciTech Connect

An electrochemical method for metal ion separations, called Electrically Switched Ion Exchange, is described. Direct oxidation and reduction of an electroactive film attached to an electrode surface is used to load and unload the film with alkali metal cations. The electroactive films under investigation are Ni hexacyanoferrates, which are deposited on the surface by applying an anodic potential to a Ni electrode in a solution containing the ferricyanide anion. Reported film preparation procedures were modified to produce films with improved capacity and stability. Electrochemical behavior of the derivatized electrodes were investigated using cyclic voltammetry and chronocoulometry. The films show selectivity for Cs in concentrated sodium solutions. Raman spectroscopy was used to monitor changes in oxidation state of the film and imaging experiments have demonstrated that the redox reactions are spatially homogenous across the film. Requirements for a bench scale unit were identified.

Lilga, M.A.; Orth, R.J.; Sukamto, J.P.H. [Pacific Northwest National Lab., Richland, WA (United States); Schwartz, D.T.; Haight, S.M. [Washington Univ., Seattle, WA (United States); Genders, D. [Electrosynthesis Co., Inc., Cheektowaga, NY (United States)

1996-12-01

188

Ion Exchange Chromatography and Mass Spectrometric Methods for Analysis of Cadmium-Phytochelatin (II) Complexes  

PubMed Central

In this study, in vitro formed Cd-phytochelatin (PC2) complexes were characterized using ion exchange chromatography (IEC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The ratio of both studied compounds as well as experimental conditions were optimized. The highest yield of the complex was observed under an applied concentration of 100 µg·mL?1 PC2 and 100 µg·mL?1 of CdCl2. The data obtained show that IEC in combination with MALDI-TOF is a reliable and fast method for the determination of these complexes. PMID:23538727

Merlos Rodrigo, Miguel Angel; Cernei, Natalia; Kominkova, Marketa; Zitka, Ondrej; Beklova, Miroslava; Zehnalek, Josef; Kizek, Rene; Adam, Vojtech

2013-01-01

189

Ion exchange chromatography and mass spectrometric methods for analysis of cadmium-phytochelatin (II) complexes.  

PubMed

In this study, in vitro formed Cd-phytochelatin (PC2) complexes were characterized using ion exchange chromatography (IEC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The ratio of both studied compounds as well as experimental conditions were optimized. The highest yield of the complex was observed under an applied concentration of 100 µg·mL(-1) PC2 and 100 µg·mL(-1) of CdCl2. The data obtained show that IEC in combination with MALDI-TOF is a reliable and fast method for the determination of these complexes. PMID:23538727

Rodrigo, Miguel Angel Merlos; Cernei, Natalia; Kominkova, Marketa; Zitka, Ondrej; Beklova, Miroslava; Zehnalek, Josef; Kizek, Rene; Adam, Vojtech

2013-04-01

190

Quantitative separations of La(III) from alkaline earth metal ions using a new, poorly crystalline inorganic ion exchanger: niobium molybdate  

SciTech Connect

Preparation of niobium molybdate for use as an ion-exchange material is described. The material has a Nb/Mo mole ratio of 0.9346 and has a high thermal stability. Results of ir, x-ray, thermogravimetric and differential scanning calorimetric analyses of the niobium molybdate are reported. The niobium molybdate is useful as an ion exchanger up to 300/sup 0/C. Determination of the distribution coefficients of 14 metal ions in demineralized water and 10/sup -2/M HNO/sub 3/ on the molybdate indicated high absorption toward Cu(II), Bi(III), La(III), Pr(III), and Th(IV); but low absorption for alkaline earth metal ions, Zn(II), Cd(II), Mn(II), and Al(III). (BLM)

Qureshi, M.; Gupta, A.P.; Thakur, J.S.; Singh, V.P.

1980-01-01

191

Early milestones in the development of ion-exchange chromatography: a personal account  

Microsoft Academic Search

Ion chromatography as we know it today was built on a foundation of knowledge accumulated over a period of many years. Here, we review some of the outstanding earlier achievements in ion-exchange chromatography. Beginning about 1947, Spedding and Powell at Iowa State published a series of papers describing practical methods for preparative separation of the rare earths by displacement ion-exchange

James S Fritz

2004-01-01

192

Water softening by single-bowl ion exchange filter efficiency estimate and improvement  

E-print Network

The article presents results of experimental investigations of the water softener in a laboratory installation of uninterruptible countercurrent ion exchange filter, which has a movable layer of ion exchange material. The installation provides for two simultaneous processes: counter ion sorption and regeneration of the sorbent with the processing capability of the sorbent in the regeneration zone by ultrasonic radiation.

Kostygin, V A; Kochetov, G M; Tugay, A M; Vashchenko, V N

2014-01-01

193

Ion-exchange membrane capacitive deionization: A new strategy for brackish water desalination  

Microsoft Academic Search

Membrane capacitive deionization (MCDI) integrates the advantages of capacitive deionization (CDI) and ion-exchange membrane technology and has shown great potential to improve the desalting efficiency. MCDI works based on the same working principle of CDI. In addition, ion-exchange membranes are introduced in front of the electrodes so that the charged ions can be selectively passed through the membrane layer and

Haibo Li; Linda Zou

2011-01-01

194

Ion-exchange studies on poly-o-anisidine Sn(IV) phosphate nano composite and its application as Cd(II) ion-selective membrane electrode  

Microsoft Academic Search

An organic-inorganic composite, poly-o-anisidine Sn(IV) phosphate, was chemically synthesized by mixing ortho-anisidine into\\u000a gels of Sn(IV) phosphate with different mixing volume ratios. Studies on the effect of eluant concentration, elution behavior\\u000a and separation of metal ions were carried out to understand the ion-exchange capabilities. Due to Cd(II) selective nature\\u000a of composite, revealed by distribution studies, Cd(II) ion selective membrane electrode

Asif Ali Khan; Anish Khan

2010-01-01

195

Anion selective membrane. [ion exchange resins and ion exchange membrane electrolytes for electrolytic cells  

NASA Technical Reports Server (NTRS)

Experimental anion permselective membranes were prepared and tested for their suitability as cell separators in a chemical redox power storage system being developed at NASA-Lewis Research Center. The goals of long-term (1000 hr) oxidative and thermal stability at 80 C in FeCl3 and CrCl3 electrolytes were met by most of the weak base and strong base amino exchange groups considered in the program. Good stability is exhibited by several of the membrane substrate resins. These are 'styrene' divinylbenzene copolymer and PVC film. At least four membrane systems produce strong flexible films with electrochemical properties (resistivity, cation transfer) superior to those of the 103QZL, the most promising commercial membrane. The physical and chemical properties of the resins are listed.

Alexander, S. S.; Geoffroy, R. R.; Hodgdon, R. B.

1975-01-01

196

Cu-Na ion exchange soda-lime glass planar waveguides and their photoluminescence  

NASA Astrophysics Data System (ADS)

Copper ion exchange technique was used to fabricate soda-lime glass planar waveguides. Prism coupling method was applied to measure the effective indices, and the refractive index profiles were reconstructed through Inverse WKB (IWKB) method. Optical absorption and photoluminescence analysis were carried out as well. The emission spectra centered at 520nm are attributed to Cu+ located in distorted octahedral sites. It was found that the ion exchange time and temperature both play an important role in the waveguides luminescence properties. The emission spectra intensities decrease with the ion exchange time increasing. The emission peak wavelength slightly blue shifts as the ion-exchange time increasing as well. The emission band intensity nearly increases consistently with the ion-exchange temperature increasing within proper ion-exchange time. Different excitation wavelengths were tested as well in order to study the site effect on photoluminescence properties.

Ti, Yunqiang; He, Xin; Zhang, Jian; Zheng, Jie; Wang, Pengfei; Farrell, Gerald

2009-11-01

197

Ammonia removal from wastewater by ion exchange in the presence of organic contaminants.  

PubMed

The scope of this study was the removal of ammonium by ion exchange from simulated wastewater. The study looks at the effect of organics upon ammonium ion exchange equilibrium uptake. The ion exchangers included a natural zeolite clinoptilolite, and two polymeric exchangers, Dowex 50w-x8, and Purolite MN500. The organic compounds studied included citric acid and a number of proteins. The traditional method for removal of ammonium and organic pollutants from wastewater is biological treatment, but ion exchange offers a number of advantages including the ability to handle shock loadings and the ability to operate over a wider range of temperatures. The results show that in most of the cases studied, the presence of organic compounds enhances the uptake of ammonium ion onto the ion exchangers. PMID:12697216

Jorgensen, T C; Weatherley, L R

2003-04-01

198

Ion exchange at TNX using the SKID unit  

SciTech Connect

An ion exchange unit has been manufactured for WSRC by British Nuclear Fuels, Ltd. This unit consists of three columns, ancillary valving, pumps, lines, and computer controls. It has been delivered to TNX for use in testing a cesium-specific ion exchange resin, developed at WSRC as a potential second generation process for the decontamination of Defense Waste Processing Facility (DWPF) supernate. This resin also has Department of Energy applications at both Oak Ridge and Hanford. Oak Ridge is interested in decontaminating the Melton Valley storage tank supernate, while Hanford is interested in decontaminating the 101-AW and 101-SY supernate streams. Another potential developmental interest is the Savannah River Site (SRS) DWPF recycle stream. The three primary waste streams of interest are the Oak Ridge, Hanford, and SRS, SWPF supernate streams. For these three waste streams, the cesium decontamination factor (DF) will be measured for a non-radioactive, simulated, high-level waste solution. The test objectives, process outlines, and broad characterization of the waste streams are described.

Meyer, M.L.; Bibler, J.P.

1993-10-21

199

Data quality objectives for Ion Exchange Module (IXM) disposition  

SciTech Connect

This Data Quality Objective (DQO) document presents the data needs and accuracy requirements for sampling ion exchange modules at the K Basins, 100 K Area, to determine if there is a hydrogen gas buildup within the modules. This document was produced by PNL, with the assistance of Neptune and Associates, and was partly funded (for facilitator) by DOE-HQ as a demonstration DQO for EM activities. PNL involved a number of PNL, WHC and support contract staff (including external technical consultants) in meetings to define the data needed, along with the necessary accuracy, to resolve issues associated with hydrogen accumulation in Ion Exchange Modules (IXMS) that were generated prior to July 1994 and only have one nuc-fil vent. IXMs generated after July 1994 have multiple nuc-fil vents and do not require sampling. PNL transmitted this DQO to WHC on January 31, 1995. This Supporting Document is to assure that the document is captured into the document retrieval system. WHC review focused on the acceptability of the technical conclusions such that the data collected will meet minimum operational, safety and environmental needs.

Choi, I. [Pacific Northwest Lab., Richland, WA (United States)

1995-01-31

200

The kinetics and mechanism of bromide ion isotope exchange reaction in strongly basic anion-exchange resin duolite A-162 determined by the radioactive tracer technique  

Microsoft Academic Search

In the present investigation, 82Br radioactive isotope was used as a tracer to study the kinetics and mechanism of exchange reaction between an ion exchange\\u000a resin and an external bromide ion solution. In an attempt to study the reversible bromide ion isotopic exchange reaction kinetics,\\u000a it was expected that whether the initial step was the exchange of radioactive bromide ions

R. S. Lokhande; P. U. Singare; P. Karthikeyan

2007-01-01

201

Selective exchange of divalent transition metal ions in cryptomelane-type manganic acid with tunnel structure  

SciTech Connect

The ion-exchange selectivity of divalent transition metal ions on cryptomelane-type manganic acid (CMA) with tunnel structure has been studied using the distribution coefficients ([ital K][sub [ital d

Tsuji, M. (Department of Chemistry, Faculty of Science, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152 (Japan)); Komarneni, S. (Materials Research Laboratory and Department of Agronomy, The Pennsylvania State University, University Park, Pennsylvania 16802-4801 (United States))

1993-03-01

202

Sorption of uranyl ions from various acido systems by amphoteric epoxy amine ion-exchange resins  

SciTech Connect

Sorption of uranyl ions by epoxy amine ampholytes with N-monomethylenephosphonic acid groups modified with pyridine or quaternary ammonium groups was studied under dynamic conditions. Heterocyclic nitrogen favors sorption of uranyl ion from fluoride, sulfate, and fluoride-sulfate solutions. The ESR studies of mono- and bimetallic forms of nitrogen-containing ampholytes with copper(II) as paramagnetic marker revealed the characteristics of uranium(VI) interaction with cation- and anion-exchange groups and its dependence on the fluoride content in solution.

Rychkov, V.N.; Radionov, B.K.; Molochnikov, L.S. [and others

1995-03-01

203

Exchange bias in polycrystalline magnetite films made by ion-beam assisted deposition  

NASA Astrophysics Data System (ADS)

Iron oxide films were produced using ion-beam-assisted deposition, and Raman spectroscopy and x-ray diffraction indicate single-phase magnetite. However, incorporation of significant fractions of argon in the films from ion bombardment is evident from chemical analysis, and Fe/O ratios are lower than expected from pure magnetite, suggesting greater than normal disorder. Low temperature magnetometry and first-order reversal curve measurements show strong exchange bias, which likely arises from defects at grain boundaries, possibly amorphous, creating frustrated spins. Since these samples contain grains ˜6 nm, a large fraction of the material consists of grain boundaries, where spins are highly disordered and reverse independently with external field.

Kaur, Maninder; Jiang, Weilin; Qiang, You; Burks, Edward C.; Liu, Kai; Namavar, Fereydoon; McCloy, John S.

2014-11-01

204

Ion exchange study of some new biphenol–thiourea–formaldehyde terpolymer resins  

Microsoft Academic Search

Terpolymer resins, synthesized by reacting 2,2?-dihydroxybiphenyl with thiourea and formaldehyde in presence of HCl as catalyst, proved to be selective chelating ion-exchange resins for certain metal ions. Chelating ion-exchange properties of these terpolymer were studied for Fe3+, Cu2+, Ni2+, Co2+, Zn2+, Cd2+ and Pb2+ ions. A batch equilibrium method has been employed in the study of the selectivity of metal

Manjusha M. Jadhao; Mukesh Thite; L. J. Paliwal; N. S. Bhave

2012-01-01

205

Isotope yield ratios of fragments from heavy-ion reactions  

SciTech Connect

Isotope yield ratios produced in collisions of 35 MeV/nucleon {sup 14}N with targets of C, Ni, Ag, and Ho have an exponential dependence on total neutron-to-proton ratio. A statistical multifragmentation model including particle emission from excited fragments predicted such behavior for yield ratios measured earlier at the higher energy of 84 MeV/nucleon.

Deak, F.; Kiss, A. (Department of Atomic Physics, Eoetvoes University, Puskin utca 5-7, H-1088 Budapest, Hungary (HU)); Seres, Z. (Central Research Institute for Physics, H-1525 Budapest 114, Hungary (HU)); Galonsky, A.; Heilbronn, L. (National Superconducting Cyclotron Laboratory and Department of Physics Astronomy, Michigan State University, East Lansing, Michigan 48824 (USA))

1991-05-01

206

Copper ion-exchanged channel waveguides optimization for optical trapping.  

PubMed

Optical trapping of particles has become a powerful non-mechanical and non-destructive technique for precise particle positioning. The manipulation of particles in the evanescent field of a channel waveguide potentially allows for sorting and trapping of several particles and cells simultaneously. Channel waveguide designs can be further optimized to increase evanescent field prior to the fabrication process. This is crucial in order to make sure that the surface intensity is sufficient for optical trapping. Simulation configurations are explained in detail with specific simulation flow. Discussion on parameters optimization; physical geometry, optical polarization and wavelength is included in this paper. The effect of physical, optical parameters and beam spot size on evanescent field has been thoroughly discussed. These studies will continue toward the development of a novel copper ion-exchanged waveguide as a method of particle sorting, with biological cell propulsion studies presently underway. PMID:23726859

Reshak, A H; Khor, K N; Shahimin, M M; Murad, S A Z

2013-08-01

207

Peptide Orientation Affects Selectivity in Ion-Exchange Chromatography  

SciTech Connect

Here we demonstrate that separation of proteolytic peptides, having the same net charge and one basic residue, is affected by their specific orientation toward the stationary phase in ion-exchange chromatography. In electrostatic repulsion-hydrophilic interaction chromatography (ERLIC) with an anion-exchange material, the C-terminus of the peptides is, on average, oriented toward the stationary phase. In cation exchange, the average peptide orientation is the opposite. Data with synthetic peptides, serving as orientation probes, indicate that in tryptic/Lys-C peptides the C-terminal carboxyl group appears to be in a zwitterionic bond with the side chain of the C-terminal Lys/Arg residue. In effect, the side chain is then less basic than the N-terminus, accounting for the specific orientation of tryptic and Lys-C peptides. Analyses of larger sets of peptides, generated from lysates by either Lys-N, Lys-C, or trypsin, reveal that specific peptide orientation affects the ability of harged side chains, such as phosphate residues, to influence retention. Phosphorylated residues that are remote in the sequence from the binding site affect retention less than those that are closer. When a peptide contains multiple charged sites, then orientation is observed to be less rigid and retention tends to be governed by the peptide’s net charge rather than its sequence. These general observations could be of value in confirming a peptide’s identification and, in particular, phosphosite assignments in proteomics analyses. More generally, orientation accounts for the ability of chromatography to separate peptides of the same compositionbut different sequence.

Alpert, Andrew J.; Petritis, Konstantinos; Kangas, Lars J.; Smith, Richard D.; Mechtler, Karl; Mitulovic, Goran; Mohammed, Shabaz; Heck, Albert J.

2010-06-15

208

A comparative study of adsorption of perfluorooctane sulfonate (PFOS) onto granular activated carbon, ion-exchange polymers and non-ion-exchange polymers.  

PubMed

Perfluorooctane sulfonate (PFOS) is the latest chemical categorized as persistent organic pollutants (POPs). PFOS appears in the environmental water and tap water in ng L(-1) level. The process of adsorption has been identified as an effective technique to eliminate PFOS in water. Three non-ion-exchange polymers (DowV493, DowL493 and AmbXAD4), two ion-exchange polymers (DowMarathonA and AmbIRA400) and one granular activated carbon (GAC) (Filtersorb400) were tested with regard to their sorption kinetics and isotherms at low PFOS concentrations (100-1000 ng L(-1) equilibrium concentrations). The sorption capacities at 1 microg L(-1) equilibrium concentration decreased in the following order: ion-exchange polymers>non-ion-exchange polymers > GAC, but at further low equilibrium concentration (100 ng L(-1)) non-ion-exchange polymers showed higher adsorption capacity than other adsorbents. In the case of sorption kinetics, GAC and ion-exchange polymers reached the equilibrium concentration within 4 h and AmbXAD4 within 10 h. DowV493 and DowL493 took more than 80 h to reach equilibrium concentration. AmbIRA400 was identified as the best filter material to eliminate PFOS at equilibrium concentration > 1000 ng L(-1). Considering both adsorption isotherms and adsorption kinetics, AmbXAD4 and DowMarathonA were recommended to eliminate PFOS at ng L(-1) equilibrium concentration. PMID:20546842

Senevirathna, S T M L D; Tanaka, S; Fujii, S; Kunacheva, C; Harada, H; Shivakoti, B R; Okamoto, R

2010-07-01

209

Materials for Electroactive Ion-Exchange (EaIX) Separations of Pertechnetate Ion  

SciTech Connect

Many contaminants of interest to the U.S. Department of Energy (DOE) exist as anions (e.g. chromate, pertechnetate and nitrate). The objective of this study is to develop Electroactive Ion-Exchange (EaIX) materials. Such materials can be used to separate pertechnetate ion from radioactive wastes located at DOE sites while limiting the amount of secondary wastes generated. We have developed a synthetic strategy to prepare vinyl-bipyridyl and -terpyridyl ligands which allow incorporation of ion-selective architectures with a polymerizable handle. Fe complexes formed with these ligands provide the working core of the electroactive polymers. The polymers can be directly used as materials for EaIX or they can be incorporated into porous composite materials that are then used for EaIX.

Stender, Matthias; Hubler, Timothy L.; Alhoshan, Mansour; Smyrl, William H.

2004-03-29

210

Truly Incomplete and Complex Chromosomal Exchanges in Human Fibroblast Cells Exposed In Situ to Energetic Heavy Ions  

NASA Technical Reports Server (NTRS)

Confluent human fibroblast cells (AG 1522) were irradiated with gamma rays, 490 MeV/nucleon Si, or with Fe ions at either 200 or 500 MeV/nucleon. The cells were allowed to repair at 37 C for 24 hours after exposure, and a chemically induced premature chromosome condensation (PCC) technique was used to condense chromosomes in the G2 phase of the cell cycle. Incomplete and complex exchanges were analyzed in the irradiated samples. In order to verify that chromosomal breaks were truly unrejoined, chromosome aberrations were analyzed using a combination of whole chromosome specific probes and probes specific for the telomere region of the chromosome. Results showed that the frequency of unrejoined chromosome breaks was higher after high-LET radiation, and consequently, the ratio of incomplete to complete exchanges increased steadily with LET up to 440 keV/micron, the highest LET value in the present study. For samples exposed to 200 MeV/nucleon Fe ions, chromosome aberrations were analyzed using the multicolor FISH (mFISH) technique that allow identification of both complex and truly incomplete exchanges. Results of the mFISH study showed that 0.7 and 3 Gy dose of the Fe ions produced similar ratios of complex to simple exchanges and incomplete to complete exchanges, values for which were higher than those obtained after a 6 Gy gamma exposure. After 0.7 Gy of Fe ions, most complex aberrations were found to involve three or four chromosomes, which is a likely indication of the maximum number of chromosome domains traversed by a single Fe ion track.

Wu, Honglu; Durante, marco; Furusawa, Yoshiya; George, Kerry; Kawata, Tetsuya; Cucinotta, Francis A.

2003-01-01

211

Anion-exchange separations of metal ions in thiocyanate media.  

PubMed

The analytical potential of a weak-base macroreticular anion-exchange resin for the quantitative separation of metal ions in thiocyanate media is investigated and demonstrated. Distribution data are given for the sorption of some 25 metal ions from aqueous mixtures of potassium thiocyanate (1.0M or less) and 0.5M hydrochloric acid. The magnitude of the distribution data suggests many possible separations, some of which were quantitatively performed by procedures which are fast, simple and require only mild conditions. Representative separations are removal of traces of iron(III) and copper(II) from water samples prior to the determination of water hardness (calcium and magnesium), separation of nickel(II) from vanadium(IV) and the separation of thorium(IV) from titanium(IV). Some multicomponent separations are the separation of rare earths(III) and thorium(IV) from scandium(III) and the separation of rare earths(III) from iron(III) and uranium(VI). PMID:18960914

Fritz, J S; Kaminski, E E

1971-05-01

212

Magnetic ion exchange treatment of stabilized landfill leachate.  

PubMed

Stabilized landfill leachate is characterized by a high concentration of non-biodegradable organic matter, which is similar in chemistry to dissolved organic matter (DOM) in the natural aquatic environment. Magnetic ion exchange (MIEX) resin treatment is well-studied in drinking water for removal of DOM from natural waters. There are fewer studies evaluating MIEX treatment of waste waters, and there is no previous work evaluating MIEX treatment of landfill leachate. This work systematically evaluated MIEX treatment of stabilized landfill leachate and evaluated the results in the context of previous studies of MIEX treatment of natural and waste waters. Five leachates from four landfills were evaluated as a function of MIEX resin dose, mixing time, and regeneration efficiency. MIEX resin removed DOM from landfill leachate, even in the presence of a reported high background concentration of inorganic ions. MIEX resin that was exhausted with leachate DOM was effectively regenerated with a concentrated NaCl solution, and regenerated MIEX resin performed similarly to virgin resin. For a majority of the leachates, the removal trend for MIEX resin was color>UV-absorbing substances>dissolved organic carbon?COD>total nitrogen. Finally, MIEX resin removed a wider range of DOM from leachate than coagulation. The most important contribution of this work is that MIEX treatment of leachate followed very similar trends as MIEX treatment of natural waters, which will allow previous MIEX data to be used to estimate the treatment efficiency of other waste waters. PMID:21497879

Boyer, Treavor H; Graf, Katherine C; Comstock, Sarah E H; Townsend, Timothy G

2011-05-01

213

Influence of specially modulated ultrasound on the water desalination process with ion-exchange hollow fibers  

Microsoft Academic Search

The enhancing effect of specially modulated ultrasound signals (SMUS) on the process of water desalination by means of ion-exchange hollow fibers was investigated. For Na+ - H+ ion exchange the enhancement effect increased with increasing power of the ultrasound, reaching about 40% at a signal power of 61 W. Depending on the concentration of the solutions and hydrodynamic conditions, ultrasound

M. Band; M. Gutman; V. Faerman; E. Korngold; J. Kost; P. J. Plath; V. Gontar

1997-01-01

214

Ion exchange resins. (Latest citations from the EI Compendex*plus database). Published Search  

SciTech Connect

The bibliography contains citations concerning preparation, properties, and applications of ion exchange resins. Applications include water and waste treatment, chemical recovery, separation, purification, catalysis, desalination, and ore treatment. Regeneration and disposal of ion exchange resins are also covered. (Contains 250 citations and includes a subject term index and title list.)

NONE

1995-01-01

215

REMOVAL OF URANIUM FROM DRINKING WATER BY ION EXCHANGE AND CHEMICAL CLARIFICATION  

EPA Science Inventory

A pilot demonstration was conducted of ion exchange and chemical clarification equipment for removing uranium from drinking water. Four commercial-type ion exchange columns and a prefiltering and regeneration solution system were constructed along with a pilot-scale chemical clar...

216

Biological treatment of ion-exchange brine regenerant for re-use: A review  

Microsoft Academic Search

Ion-exchange resins are typically selected to target anionic pollutants in drinking water treatment, however, the production of concentrated brine is a significant disadvantage as regulation of its disposal is becoming increasingly strict. Various destructive technologies have been trialled as a replacement for ion exchange, the most notable being biological reduction. Although several full-scale biological processes have been developed for drinking

E. J. McAdam; S. J. Judd

2008-01-01

217

Influence of temperature on ion-exchange equilibrium accompanied by complex formation in resins  

Microsoft Academic Search

The paper deals with finding the correlation between the influence of temperature on the ionic selectivity of ion-exchange resins studied experimentally and their chemical structures. The effects of temperature on selectivity of resins are compared with the data for the soluble complexing reagents. The physicochemical basis of the influence of temperature on ion-exchange selectivity is considered.

V. A. Ivanov; V. I. Gorshkov; V. D. Timofeevskaja; N. V. Drozdova

1998-01-01

218

Use of selectively buried ion-exchange waveguides for the realization of Bragg grating filters  

Microsoft Academic Search

Ion exchange on glass substrates has proved to be an efficient low cost and high performance technology to realise integrated optic devices. Among structures developed thanks to this technology, those presenting both surface and buried waveguides are of great interest. In this paper, we first describe a fabrication process of selectively buried ion exchange waveguides. Its principle is based on

Odile Bertoldi; Jean-Emmanuel Broquin; Guy Vitrant; Virginie Collomb; Michel Trouillon; Vincent Minier

2004-01-01

219

Glass processing by ion exchange to fabricate integrated optical planar components: applications  

Microsoft Academic Search

Ion-Exchanged Glass Integrated Optics has received a considerably attention during the laser years because of their well-known advantages. On the other hand, ion- exchanged waveguide components are finding important applications in the implementation of analogue processing devices, optical sensing devices and some kind of circuit for optical communications. Many of these develop devices are based on channel guides, however planar

Jesus Linares; Carlos Montero; Vicente Moreno; Maria C. Nistal; Xesus Prieto; Jose R. Salgueiro; Diego Sotelo

2000-01-01

220

Design of high efficiency fibers for ion exchange and heavy metal removal  

Microsoft Academic Search

Ion exchange materials coated on glass fiber substrates have a number of advantages over the conventional ion exchange beads. These include simplification of the overall synthesis including faster more efficient functionalization and elimination of toxic solvents. Other benefits include the ability to be fabricated in the form of felts, papers, or fabrics, improving media contact efficiency and enhancing both the

Lourdes Dominguez

2002-01-01

221

Use of aminocarboxylic ion-exchangers to purify ammonium molybdate and tungstate solutions  

Microsoft Academic Search

A number of new, commercial aminocarboxylic ion-exchangers have appeared in recent years, but with no studies on whether they can be used to prepare high purity molybdenum and tungsten compounds. This paper reports properties of those domestic aminocarboxylic ion-exchangers most promising for the purification of ammonium molybdate (AM) and ammonium tungstate (AT) solutions. Changes in the concentration of magnesium, copper,

A. A. Blokhin; M. I. Semenov; V. P. Taushkanov; V. A. Vakolenko

1986-01-01

222

THERMAL MODELING ANALYSIS OF CST MEDIA IN THE SMALL COLUMN ION EXCHANGE PROJECT  

Microsoft Academic Search

Models have been developed to simulate the thermal characteristics of Crystalline Silicotitanate (CST) ion exchange media fully loaded with radioactive cesium in a column configuration and distributed within a waste storage tank. This work was conducted to support the Small Column Ion Exchange (SCIX) program which is focused on processing dissolved, high-sodium salt waste for the removal of specific radionuclides

2010-01-01

223

Effects of gamma irradiation on cobalt hexacyanoferrate(II) ion exchangers  

NASA Astrophysics Data System (ADS)

Study was made of the effects of ? irradiation doses of 2.1 and 5.0 MGy on the structure and cesium ion exchange properties of potassium cobalt hexacyanoferrate(II) and a composite ion exchanger, sodium cobalt hexacyanoferrate(II) in a chelating ion exchange resin. In the case of the potassium cobalt hexacyanoferrate only a slight increase in crystal size was observed. The composite exchanger withstood the lower dose, but at the higher dose the organic resin decomposed, leaving a residue of sodium cobalt hexacyanoferrate.

Lehto, J.; Szirtes, L.

1994-03-01

224

Nanomaterials-Enhanced Electrically Switched Ion Exchange Process for Water Treatment  

SciTech Connect

The objective of our work is to develop an electrically switched ion exchange (ESIX) system based on conducting polymer/carbon nanotube (CNT) nanocomposites as a new and cost-effective approach for removal of radioactive cesium, chromate, and perchlorate from contaminated groundwater. The ESIX technology combines ion exchange and electrochemistry to provide a selective, reversible method for the removal of target species from wastewater. In this technique, an electroactive ion exchange layer is deposited on a conducting substrate, and ion uptake and elution are controlled directly by modulation of the potential of the layer. ESIX offers the advantages of highly-efficient use of electrical energy combined with no secondary waste generation. Recently, we have improved upon the ESIX process by modifying the conducting substrate with carbon nanotubes prior to the deposition of the electroactive ion exchanger. The nanomaterial-based electroactive ion exchange technology will remove cesium-137, chromate, and perchlorate rapidly from wastewater. The high porosity and high surface area of the electroactive ion exchange nanocomposites results in high loading capacity and minimize interferences for non-target species. Since the ion adsorption/desorption is controlled electrically without generating a secondary waste, this electrically active ion exchange process is a green process technology that will greatly reduce operating costs.

Lin, Yuehe; Choi, Daiwon; Wang, Jun; Bontha, Jagannadha R.

2009-01-01

225

Calculation method for the determination of ion-exchange sorption of lysine from culture liquor  

Microsoft Academic Search

liquor (CL) by means of ionites. Most important for selecting the optimal ion exchange technnlogy is the preliminary calculation of the lysine sorption on the ionite, depending on the exchange conditions, cationic composition of the CL, and the ionic form of the resin. The calculation can be based on the exchange of lysine in a multicomponent system, containing, in a

E. M. Ter-Sarkisyan; D. S. Kutukov; L. M. Evstyuzov-Babaev

1979-01-01

226

Physicochemical basis of the ion-exchange separation of gold cyanide complexes  

NASA Astrophysics Data System (ADS)

The mechanism of the separation of gold cyanide complexes is discussed, along with ion exchanger selection, selectivity, elution, and industrial applications. The ion-exchange mechanism for the sorption of gold cyanide complexes is established, and a criterion is suggested for selecting the anion exchanger for their extraction (specifically, the p K a of the anion exchanger). The selectivity of the sorption of gold cyanide complexes by anion exchangers with rarely distributed ionogenic groups is demonstrated. A procedure for the elution of gold cyanide complexes using alkaline solutions is developed.

Kononova, O. N.; Kononov, Yu. S.

2014-10-01

227

Systematic study of the ?-/?+ ratio in heavy-ion collisions with the same neutron/proton ratio but different masses  

NASA Astrophysics Data System (ADS)

A systematic study of the ?-/?+ ratio in heavy-ion collisions with the same neutron/proton ratio but different masses can help single out effects of the nuclear mean field on pion production. Based on simulations using the IBUU04 transport model, it is found that the ?-/?+ ratio in head-on collisions of Ca48+Ca48, Sn124+Sn124, and Au197+Au197 at beam energies from 0.25 to 0.6 GeV/nucleon increases with increasing the system size or decreasing the beam energies. A comprehensive analysis of the dynamical isospin fractionation and the ?-/?+ ratio as well as their time evolution and spatial distributions demonstrates clearly that the ?-/?+ ratio is an effective probe of the high-density behavior of the nuclear symmetry energy.

Zhang, Ming; Xiao, Zhi-Gang; Li, Bao-An; Chen, Lie-Wen; Yong, Gao-Chan; Zhu, Sheng-Jiang

2009-09-01

228

Application of the new thermodynamic approach to the description of superequivalent sorption by ion exchangers  

NASA Astrophysics Data System (ADS)

Using the example of sorption systems with the participation of amino acids, it is shown that the novel thermodynamic approach to describing superequivalent sorption as a combination of ion exchange and nonexchangeable absorption allows us to adequately describe such equilibria. Results from calculating the activity coefficients of components of a sorbent phase and the thermodynamic constants of ion exchange equilibrium and the superequivalent absorption of phenylalanine by AV-17-8 anion exchange resin are presented.

Khokhlova, O. N.

2014-08-01

229

REMOVAL OF IRON FROM AQUEOUS SOLUTIONS BY ION EXCHANGE WITH NAY ZEOLITE  

Microsoft Academic Search

Iron removal from aqueous solutions by batch ion exchange with a solid Na-Y zeolite has been studied. The pH of the solution was monitored continuously during the ion exchange process and the impact of pH on iron hydroxide precipitation and zeolite structural stability is discussed. In the case of the Fe(II)\\/Na-Y exchange system, the pH of the iron solutions was

Jong Sung Kim; Ling Zhang; Mark A. Keane

2001-01-01

230

Ion-exchange-based eluent-free preconcentration of some anions  

Microsoft Academic Search

Preconcentration procedures based on ion-exchange methods are often used to enhance the sensitivities of analytical techniques where the eluent used for eluting the preconcentrated ions does not influence the subsequent analytical step. Until recently, only a limited use of ion-exchange-based sample preconcentration procedures has been found in those analytical techniques where the eluent components strongly influence the separation procedure [e.g.,

Milko Novi?; Marjan Gu?ek; Janja Turši?; Yan Liu; Nebojsa Avdalovic

2001-01-01

231

Studies on decontamination of spent ion exchange resin used for plutonium purification in PUREX stream  

Microsoft Academic Search

This paper deals with the studies on decontaminations of spent ion exchange resin used for purification of plutonium in PUREX\\u000a process stream. Studies were carried out to optimize the chemical procedure for removal of plutonium and fission products\\u000a activities form spent Ion Exchange resin. Different metal complexing reagents were tested for leaching out of radionuclides\\u000a entrapped in irradiated spent ion

K. K. Gupta; Suman Kumar Singh; G. A. Inamdar; A. Madhusudan; S. C. Tripathi

2009-01-01

232

Limits on aspect ratio in two-fluid microscale heat exchangers  

SciTech Connect

This research investigates the theoretical limit on aspect ratio within two-fluid counter-flow microchannel heat exchangers. The counter-flow device is comprised of alternating layers of microchannels, which allow the two fluids to flow in opposite directions, separated by fins. A theoretical model for interpreting the span of the fin as a function of the fin thickness is established. The model is verified experimentally by fabricating two kinds of test specimens to simulate the counter-flow device. Results from metallography and leakage testing reveal that for a given set of bonding conditions, there exists a maximum permissible value of elastic fin deflection during bonding beyond which leakage is bound to occur. Furthermore, the results imply that higher aspect ratios can be achieved at smaller scales.

Paul, B.K. (Oregon State Univ., Corvallis, OR); Hasan, Hadi (Oregon State Univ., Corvallis, OR); Thomas, J.S. (Oregon State Univ., Corvallis, OR); Wilson, R.D.

2001-01-01

233

Selectivity of ion exchangers in extracting cesium and rubidium from alkaline solutions  

NASA Astrophysics Data System (ADS)

We compare the ion exchange selectivity of phenol-type sorbents based on phenol formaldehyde resins, products of condensation of diatomic phenols with formaldehyde, and crosslinked polymer based on C-phenyl[4]resorcinarene resin, for cesium and rubidium ions. It is shown that phenol formaldehyde sorbents are the ones most selective. The interaction of alkali metal cations with the anion of calix[4]arene is investigated via quantum-chemical modeling. It is shown that the selectivity toward cesium and rubidium ions in ion exchangers of the phenolic type is not due to specific interactions of ions with phenolic groups.

Shelkovnikova, L. A.; Kargov, S. I.; Gavlina, O. T.; Ivanov, V. A.; Al'tshuler, G. N.

2013-01-01

234

Multivariate analysis of Ion Beam Induced Luminescence spectra of irradiated silver ion-exchanged silicate glasses.  

PubMed

A multivariate analysis is used for the identification of the spectral features in Ion Beam Induced Luminescence (IBIL) spectra of soda-lime silicate glasses doped with silver by Ag(+)-Na(+) ion exchange. Both Principal Component Analysis and multivariate analysis were used to characterize time-evolving IBIL spectra of Ag-doped glasses, by means of the identification of the number and of the wavelength positions of the main luminescent features and the study of their evolution during irradiation. This method helps to identify the spectral features of the samples spectra, even when partially overlapped or less intense. This analysis procedure does not require additional input such as the number of peaks. PMID:22571943

Valotto, Gabrio; Quaranta, Alberto; Cattaruzza, Elti; Gonella, Francesco; Rampazzo, Giancarlo

2012-09-01

235

Multivariate analysis of Ion Beam Induced Luminescence spectra of irradiated silver ion-exchanged silicate glasses  

NASA Astrophysics Data System (ADS)

A multivariate analysis is used for the identification of the spectral features in Ion Beam Induced Luminescence (IBIL) spectra of soda-lime silicate glasses doped with silver by Ag+-Na+ ion exchange. Both Principal Component Analysis and multivariate analysis were used to characterize time-evolving IBIL spectra of Ag-doped glasses, by means of the identification of the number and of the wavelength positions of the main luminescent features and the study of their evolution during irradiation. This method helps to identify the spectral features of the samples spectra, even when partially overlapped or less intense. This analysis procedure does not require additional input such as the number of peaks.

Valotto, Gabrio; Quaranta, Alberto; Cattaruzza, Elti; Gonella, Francesco; Rampazzo, Giancarlo

236

Coupled Ion Complexation and Exchange between Aqueous and Ionic Liquid Phases: A Thermodynamic Interpretation  

Microsoft Academic Search

Experimental studies of ion extraction from aqueous to ionic liquid phases have demonstrated that, in many cases, extraction of an ion from the aqueous phase is coupled to counterextraction of similarly charged ions from the ionic phase. These exchanges often involve coordination complexes that are not observed in extractions from aqueous phases to molecular organic liquids. We make a thermodynamic

Mark N. Kobrak

2008-01-01

237

Removal of fluoride from spent pot liner leachate using ion exchange  

SciTech Connect

Spent pot liner (SPL), a hazardous solid waste produced at cell houses of aluminum smelters, is a potential source of fluoride pollution. Leachates collected from SPL disposal sites were found to contain fluoride at considerable concentration levels. This paper reports a study of selective fluoride removal following laboratory-prepared, ion-exchange treatment. Spent pot liner leachates were pretreated with lime to bring the fluoride level down to approximately 10 mg/L for economic and effective working of the ion exchanger. The detailed ion-exchange treatment study for removal of fluoride was carried out on synthetic SPL leachates and the optimum treatment thus developed was applied on natural SPL leachates. Bench-scale studies were carried out at various flow rates and pHs and in the presence of other ions commonly available in the SPL leachates. The prepared exchanger reduced the level of fluoride from approximately 10 mg/L to less than 1 mg/L. Results indicate that the extraction was 100% up to 6-mL/min flow rate through the ion exchanger and it works efficiently in the pH range of 7 to 10. There is no effect of the other ions present in leachates on removal of fluoride. The exchanger has good capacity to exchange and can be recharged by eluting fluoride sorbed on the exchanger using two molar hydrochloric acid.

Singh, G.; Kumar, B.; Sen, P.K.; Majumdar, J.

1999-01-01

238

Crystalline Silicotitanate Ion Exchange Support for Salt-Alternatives  

SciTech Connect

The current version of crystalline silicotitanate (TAM5) is commercially available from UOP under the trade name IONSIV IE-911. TAM5 was extensively tested by several researchers and was determined as the best currently available material for removing radioisotopes from various types of nuclear wastes salt solutions stored at various DOE sites. The studies at Savannah River Technology Center (SRTC) indicated that the CST granules tend to leach into the nuclear waste simulants as it is processed by the ion exchange columns that is packed with CST granules from UOP. We, at Texas A and M University, agreed to conduct research to compliment the efforts at SRTC so that IONSIV IE-911 could be used for the treatment of nuclear waste stored at the DOE Savannah River facility. After consultation, we developed a Task Plan in January 2000. According to the agreement between Westinghouse Savannah River Company, Savannah River Technology Center, Aiken SC 29808 and, College Station, TX 77843, synthesis and the performance evaluations of crystalline silicotitanates (CST) were performed the during period of April 1 - September 30, 2000. Our main goals were delivery of a kilogram of CST (TAM5-4) synthesized at Texas A and M University in July to SRTC, performance evaluation of CST in nuclear waste simulants, and consultation mainly by telephone.

Fondeur, F.F.

2001-02-23

239

Design of zeolite ion-exchange columns for wastewater treatment  

SciTech Connect

Oak Ridge National Laboratory plans to use chabazite zeolites for decontamination of wastewater containing parts-per-billion levels of {sup 90}Sr and {sup 137}Cs. Treatability studies indicate that such zeolites can remove trace amounts of {sup 90}Sr and {sup 137}Cs from wastewater containing high concentrations of calcium and magnesium. These studies who that zeolite system efficiency is dependent on column design and operating conditions. Previous results with bench-scale, pilot-scale, and near-full-scale columns indicate that optimized design of full-scale columns could reduce the volume of spent solids generation by one-half. The data indicate that shortcut scale-up methods cannot be used to design columns to minimize secondary waste generation. Since the secondary waste generation rate is a primary influence on process cost effectiveness, a predictive mathematical model for column design is being developed. Equilibrium models and mass-transfer mechanisms are being experimentally determined for isothermal multicomponent ion exchange (Ca, Mg, Na, Cs, and Sr). Mathematical models of these data to determine the breakthrough curves for different column configurations and operating conditions will be used to optimize the final design of full-scale treatment plant. 32 refs., 6 figs., 3 tabs.

Robinson, S.M.; Arnold, W.D.; Byers, C.H.

1991-01-01

240

Growth Rate of Calcite Steps as a Function of Aqueous Calcium-to-Carbonate Ratio: Independent Attachment and Detachment of Calcium and Carbonate Ions  

SciTech Connect

Growth rates of monolayer-height steps on the {1014} calcite surface have been measured as a function of the aqueous calcium-to-carbonate ratio. The maximum growth rates of the two common crystallographic orientations were found to deviate from the ideal stoichiometric ratio of 1:1, and dissolution features were observed under supersaturated solutions containing high calcium-to-carbonate ratios. To explain these phenomena, a theory is applied that treats the rates of attachment and detachment of aqueous calcium and carbonate ions separately. The resultant attachment rate constants are 1-3 orders of magnitude smaller than the water exchange rate of the constituent aqueous ions, suggesting that ligand-exchange processes may directly drive attachment. The broader implication is that the saturation state alone is not adequate to fully describe the rates of the multiple, independent reactions that occur on mineral surfaces under these conditions.

Stack, Andrew G [ORNL; Grantham, Ms. Meg [Georgia Institute of Technology

2010-01-01

241

Sorption of microcomponents from seawater by VION KN-1 ion-exchanger  

SciTech Connect

The purpose of this work was to study the sorption properties of VION KN-1 fibrous ion-exchanger containing carboxyl groups, in continuation of earlier work on the use of fibrous ion-exchangers for extraction of valuable microcomponents from seawater. Since extraction of microcomponents by ion-exchangers includes sorption and regeneration stages, they report the results of study of both stages, using both a model solution and water from the Black Sea. Copper was chosen as the reference microcomponent; the possibility of sorption and desorption of microcomponents of seawater was also studied under full-scale conditions. Copper was determined in the solutions with the aid of an ion-selective electrode and by the atomic absorption method with flame atomization; copper, zinc, nickel, and cobalt in the ion-exchanger phase after sorption from seawater were determined by atomic absorption spectroscopy with a laser atomizer.

Kats, E.M.; Abramov, E.G.; Vul'fson, E.K.; Barash, A.N.

1988-06-20

242

Acceleration of water dissociation generated in an ion exchange membrane  

Microsoft Academic Search

Intensity of water dissociation generated in an anion exchange membrane is stronger than that in a cation exchange membrane. Violent water dissociation occurs when metallic hydroxides such as Mg(OH)2 or Fe(OH)3 are precipitated on the cation exchange membrane. When the metallic hydroxides are precipitated on the anion exchange membrane, the violent water dissociation does not occur. The accelerated water dissociation

Yoshinobu Tanaka

2007-01-01

243

Ion temperature from tangential charge exchange neutral analysis on the Tokamak Fusion Test Reactor  

SciTech Connect

Fokker-Planck simulations of the Tokamak Fusion Test Reactor (TFTR) energetic ion mode discharges were performed to evaluate the utility of deriving the central ion temperature, T/sub i/, from deuterium neutral beam charge exchange spectra above the neutral beam injection energy. The T/sub i/ values obtained from fitting the calculated spectra obtained from sightlines nearly tangent to the neutral beam injection radius reproduce the central ion temperature within +-10% over the full range of TFTR energetic ion mode parameters. The code simulations demonstrate that the ion temperature obtained from the high energy tangential deuterium charge exchange spectrum is insensitive to variations in the plasma density, Z/sub eff/, plasma current, loop voltage, and injected neutral beam power and energy. Use of this method to reduce charge exchange data from TFTR energetic ion mode plasmas is demonstrated. 17 refs., 22 figs., 2 tabs.

Fiore, C.L.; Medley, S.S.; Hammett, G.W.; Kaita, R.; Roquemore, A.L.; Scott, S.D.

1987-09-01

244

Ionophore-based ion-exchange emulsions as novel class of complexometric titration reagents.  

PubMed

Complexometric titrations rely on a drastic change of the pM value at the equivalence point with a water soluble chelator forming typically 1?:?1 complexes of high stability. The available chemical toolbox of suitable chelating compounds is unfortunately limited because many promising complexing agents are not water soluble. We introduce here a novel class of complexometric titration reagents, a suspension of polymeric nanospheres whose hydrophobic core is doped with lipophilic ion-exchanger and a selective complexing agent (ionophore). The emulsified nanospheres behave on the basis of heterogeneous ion exchange equilibria where the initial counter ion of the ion-exchanger is readily displaced from the emulsion for the target ion that forms a stable complex in the nanosphere core. Two different examples are shown with Ca(2+) and Pb(2+) as target ions. The lack of protonatable groups on the calcium receptor allows one to perform Ca(2+) titration without pH control. PMID:25205536

Zhai, Jingying; Xie, Xiaojiang; Bakker, Eric

2014-10-28

245

Ion-Exchange Properties of lon-Sieve-Type Manganese Oxides Prepared by Using Different Kinds of Introducing Ions  

Microsoft Academic Search

Three ion-sieve-type manganese oxides, HMnO(Li), HMnO(Na), and HMnO(K), were prepared by acid treatments of Li-, Na-, and K-introduced manganese oxides, respectively. Three oxides were obtained from ?-MnO and the corresponding alkali metal hydroxides by heating at 600°C. The ion-exchange properties of the adsorbents were investigated by pH titration, Kd measurements, and the adsorption of metal ions from seawater. The selectivity

Kenta Ooi; Yoshitaka Miyai; Shunsaku Katoh

1987-01-01

246

Salt Processing Through Ion Exchange at the Savannah River Site Selection of Exchange Media and Column Configuration - 9198  

SciTech Connect

The Department of Energy (DOE) has developed, modeled, and tested several different ion exchange media and column designs for cesium removal. One elutable resin and one non-elutable resin were considered for this salt processing application. Deployment of non-elutable Crystalline Silicotitanate and elutable Resorcinol Formaldehyde in several different column configurations were assessed in a formal Systems Engineering Evaluation (SEE). Salt solutions were selected that would allow a grouping of non-compliant tanks to be closed. Tests were run with the elutable resin to determine compatibility with the resin configuration required for an in-tank ion exchange system. Models were run to estimate the ion exchange cycles required with the two resins in several column configurations. Material balance calculations were performed to estimate the impact on the High Level Waste (HLW) system at the Savannah River Site (SRS). Conceptual process diagrams were used to support the hazard analysis. Data from the hazard analysis was used to determine the relative impact on safety. This report will discuss the technical inputs, SEE methods, results and path forward to complete the technical maturation of ion exchange.

Spires, Renee; Punch, Timothy; McCabe, Daniel

2009-02-11

247

Experimental Findings On Minor Actinide And Lanthanide Separations Using Ion Exchange  

SciTech Connect

This project seeks to determine if inorganic or hybrid inorganic ion-exchange materials can be exploited to provide effective americium and curium separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of the tested ion-exchange materials for actinide and lanthanide ions. During FY13, experimental work focused in the following areas: (1) investigating methods to oxidize americium in dilute nitric acid with subsequent ion-exchange performance measurements of ion exchangers with the oxidized americium and (2) synthesis, characterization and testing of ion-exchange materials. Ion-exchange materials tested included alkali titanates, alkali titanosilicates, carbon nanotubes and group(IV) metal phosphonates. Americium oxidation testing sought to determine the influence that other redox active components may have on the oxidation of Am(III). Experimental findings indicated that Pu(IV) is oxidized to Pu(VI) by peroxydisulfate, but there are no indications that the presence of plutonium affects the rate or extent of americium oxidation at the concentrations of peroxydisulfate being used. Tests also explored the influence of nitrite on the oxidation of Am(III). Given the formation of Am(V) and Am(VI) in the presence of nitrite, it appears that nitrite is not a strong deterrent to the oxidation of Am(III), but may be limiting Am(VI) by quickly reducing Am(VI) to Am(V). Interestingly, additional absorbance peaks were observed in the UV-Vis spectra at 524 and 544 nm in both nitric acid and perchloric acid solutions when the peroxydisulfate was added as a solution. These peaks have not been previously observed and do not correspond to the expected peak locations for oxidized americium in solution. Additional studies are in progress to identify these unknown peaks. Three titanosilicate ion exchangers were synthesized using a microwave-accelerated reaction system (MARS?) and determined to have high affinities for lanthanide ions in dilute nitric acid. The K-TSP ion exchanger exhibited the highest affinity for lanthanides in dilute nitric acid solutions. The Ge-TSP ion exchanger shows promise as a material with high affinity, but additional tests are needed to confirm the preliminary results. On the other hand, carbon nanotubes and nitrogen-doped carbon nanotubes exhibited low, but measureable affinities for lanthanide ions in dilute nitric acid solutions (pH 3 and 6). The MWCNT exhibited much lower affinities than the K-TSP in dilute nitric acid solutions. However, the MWCNT are much more chemically stable in concentrated nitric acid solutions and, therefore, may be candidates for ion exchange in more concentrated nitric acid solutions.

Hobbs, D. T.; Shehee, T. C.; Clearfield, A.

2013-09-17

248

Ratios  

NSDL National Science Digital Library

This set of instructional materials and problems helps students understand ratios and proportions, starting with a simple review and progressing into the more advanced territory of similar triangles. The first three pages introduce ratios, proportions, and checking proportionality and the last four pages present mathematical and real-world problems for students to solve given their understanding of ratios and proportions.

Stapel, Elizabeth

2000-01-01

249

Vitrification of ion exchange materials. Innovative technology summary report  

SciTech Connect

Ion exchange is a process that safely and efficiently removes radionuclides from tank waste. Cesium and strontium account for a large portion of the radioactivity in waste streams from US Department of Energy (DOE) weapons production. Crystalline silicotitanate (CST) is an inorganic sorbent that strongly binds cesium, strontium, and several other radionuclides. Developed jointly by Sandia National Laboratory and Texas A and M University, CST was commercialized through a cooperative research and development agreement with an industrial partner. Both an engineered (mesh pellets) and powdered forms are commercially available. Cesium removal is a baseline in HLW treatment processing. CST is very effective at removing cesium from HLW streams and is being considered for adoption at several sites. However, CST is nonregenerable, and it presents a significant secondary waste problem. Treatment options include vitrification of the CST, vitrification of the CST coupled with HLW, direct disposal, and low-temperature processes such as grouting. The work presented in this report demonstrates that it is effective to immobilize CST using a baseline technology such as vitrification. Vitrification produces a durable waste form. CST vitrification was not demonstrated before 1996. In FY97, acceptable glass formulations were developed using cesium-loaded CST obtained from treating supernatants from Oak Ridge Reservation (ORR) tanks, and the CST was vitrified in a research melter at the Savannah River Technology Center (SRTC). In FY98, SRS decided to reevaluate the use of in-tank precipitation using tetraphenylborate to remove cesium from tank supernatant and to consider other options for cesium removal, including CST. Hanford and Idaho National Engineering and Environmental Laboratory also require radionuclide removal in their baseline flowsheets.

Not Available

1999-07-01

250

Adsorption of fluoride, chloride, bromide, and bromate ions on a novel ion exchanger.  

PubMed

A novel ion exchanger based on double hydrous oxide (Fe2O3Al2O3xH2O) was obtained by the original sol-gel method from easily available and cheap raw materials and employed for adsorption of F-, Cl-, Br-, and BrO-3 from simultaneous solutions. Adsorbent was characterized by potentiometric titration, zeta-potential, and poremetrical characteristics. A technologically attractive pH effect of F-, Br-, and BrO-3 sorption on the investigated double hydroxide of Fe and Al, which is capable of working in the pH range 3 to 8.5, was observed. Kinetic data on fluoride and bromide sorption fit well the pseudo-second-order model. Isotherms of fluoride, bromide, chlorine, and bromate ion sorption on Fe2O3Al2O3xH2O were obtained at pH 4. The isotherm of F- sorption fit well the Langmuir model; sorption affinity (K=0.52 L/mg) and sorption capacity (90 mg F/g) were high. In the competitive adsorption of bromide and bromate, bromide dominated at equilibrium concentrations of the ions >40 mg/L. The mechanism of fluoride adsorption to the surface of the model cluster of the sorbent synthesized and the geometry of the cluster itself were modeled with the HyperChem7 program using the PM3 method. PMID:15964584

Chubar, N I; Samanidou, V F; Kouts, V S; Gallios, G G; Kanibolotsky, V A; Strelko, V V; Zhuravlev, I Z

2005-11-01

251

Preparation of ion exchanger layered electrodes for advanced membrane capacitive deionization (MCDI).  

PubMed

A noble electrode for capacitive deionization (CDI) was prepared by embedding ion exchanger onto the surface of a carbon electrode to practice membrane capacitive deionization (MCDI). Bromomethylated poly (2, 6-dimethyl-1, 4-phenylene oxide) (BPPO) was sprayed on carbon cloth followed by sulfonation and amination to form cation exchange and anion exchange layers, respectively. The ion exchange layers were examined by Scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FT-IR). The SEM image showed that the woven carbon cloth was well coated and connected with BPPO. The FT-IR spectrum revealed that sulfonic and amine functional groups were attached on the cationexchange and anionexchange electrodes, respectively. The advantages of the developed carbon electrodes have been successively demonstrated in a batch and a continuous mode CDI operations without ion exchange membranes for salt removal using 100 mg/L NaCl solution. PMID:21777933

Lee, Ju-Young; Seo, Seok-Jun; Yun, Sung-Hyun; Moon, Seung-Hyeon

2011-11-01

252

The Determination of Calcium in Dietary Supplement Tablets by Ion-Exchange.  

ERIC Educational Resources Information Center

An experimental simple ion-exchange experiment in which the amount of calcium present in dietary supplement tablets has been developed is described and some typical student results for several brands of tablets are presented. (JN)

Dietz, Mark L.

1986-01-01

253

Enhanced Nitrification in Constructed Wetlands Using Ion-Exchange and Biological Regeneration.  

National Technical Information Service (NTIS)

Constructed wetlands built in northern climates do not adequately remove nitrogen, especially ammoniacal nitrogen, in the winter. Clinoptilolite, an ion-exchange crystal, can be used to store ammonium from wetland effluents during the colder winter months...

M. R. Knoff

2000-01-01

254

MODELING AN ION EXCHANGE PROCESS FOR CESIUM REMOVAL FROM ALKALINE RADIOACTIVE WASTE SOLUTIONS  

SciTech Connect

The performance of spherical Resorcinol-Formaldehyde ion-exchange resin for the removal of cesium from alkaline radioactive waste solutions has been investigated through computer modeling. Cesium adsorption isotherms were obtained by fitting experimental data using a thermodynamic framework. Results show that ion-exchange is an efficient method for cesium removal from highly alkaline radioactive waste solutions. On average, two 1300 liter columns operating in series are able to treat 690,000 liters of waste with an initial cesium concentration of 0.09 mM in 11 days achieving a decontamination factor of over 50,000. The study also tested the sensitivity of ion-exchange column performance to variations in flow rate, temperature and column dimensions. Modeling results can be used to optimize design of the ion exchange system.

Smith, F; Luther Hamm, L; Sebastian Aleman, S; Johnston Michael, J

2008-08-26

255

Ion-exchange chromatography separation applied to mineral recycle in closed systems  

NASA Technical Reports Server (NTRS)

As part of the controlled ecological life support system (CELSS) program, a study is being made of mineral separation on ion-exchange columns. The purpose of the mineral separation step is to allow minerals to be recycled from the oxidized waste products of plants, man, and animals for hydroponic food production. In the CELSS application, relatively large quantities of minerals in a broad concentration range must be recovered by the desired system, rather than the trace quantities and very low concentrations treated in analytical applications of ion-exchange chromatography. Experiments have been carried out to assess the parameters pertinent to the scale-up of ion-exchange chromatography and to determine feasibility. Preliminary conclusions are that the column scale-up is in a reasonable size range for the CELSS application. The recycling of a suitable eluent, however, remains a major challenge to the suitability of using ion exchange chromatography in closed systems.

Ballou, E.; Spitze, L. A.; Wong, F. W.; Wydeven, T.; Johnson, C. C.

1981-01-01

256

Electromechanical performance and other characteristics of IPMCs fabricated with various commercially available ion exchange membranes  

NASA Astrophysics Data System (ADS)

Ionic polymer-metal composites (IPMCs) are considered as some of the favorable candidates to be used as biomimetic actuators and sensors in an aqueous environment. Amongst all components that compose an IPMC, the ion exchange membrane is where hydrated cations migrate when an electric field is applied across the membrane and it eventually produces the deformation of the IPMC. Nafion® is the most commonly used ion exchange membrane. Many studies have been conducted on IPMCs made with Nafion®. In this study, three other commercially available ion exchange membranes were used to fabricate IPMCs and their performance as actuators was compared with IPMCs made with Nafion® membrane. Their potential for use in IPMC actuators was investigated by conducting various characterizations such as water uptake, ion exchange capacity, morphology, thermal property, blocking force and bending displacement.

Park, Jiyeon; Palmre, Viljar; Hwang, Taeseon; Kim, Kwang; Yim, Woosoon; Bae, Chulsung

2014-07-01

257

Conversion of ion exchange resin to various functional resins and the application in the field of pharmaceutical sciences  

NASA Astrophysics Data System (ADS)

Ion exchange resins are widely used for separating ions in the solution, desalination, removal of impurities, and etc. Giving a new function to these ion exchange resins enables the application in more various fields. Until now, we carried out the research work about the following 5 project.: (1) Conversion of ion exchange resins into selective adsorbents by using low molecular reagents, which possess capabilities of a selective reaction with target ions, ion exchange reaction with the ion exchange resin and strong physical adsorption to the ion exchange resin. (2) Synthesis of resins for ion exchange high performance liquid chromatography (IEHPLC) and the analysis of biomaterials. (3) Development of insoluble macromolecular Sn(II) complex based on the aminophosphonic acid type ion exchange resin and its application to the 99mTc labeling of proteins. (4) Development of a new 68Ge-68Ga generator using N-methylglucamine type organic polymer as the adsorbent for 68Ge and production of 68Ga for PET. (5) Preparation of an ion-exchangeable polymer bead wrapped with bilayer membrane structures. In this paper, the application of various functional resins prepared based on ion exchange resin in the field of pharmaceutical sciences has been summarized.

Nakayama, Morio

258

Seperation of Nickel(Ii) and Cadmium(Ii) with Ion-Exchange Process  

Microsoft Academic Search

Separation of nickel(II) and cadmium(II) ions from sulphate solution has been studied. The solutions of Ni(II) and Cd(II) have been treated with different exchange resins: Lewatit OC-1026, Lewatit TP-207 and Lewatit MonoPlus SP 112. Data obtained from ion-exchange process was compared with data from supported liquid membrane experiment. It was shown that use of supported liquid membrane process enables separation

Paulina Otrembska; Jerzy G?ga

2012-01-01

259

Separation of Nickel(II) and Cadmium(II) with Ion-Exchange Process  

Microsoft Academic Search

Separation of nickel(II) and cadmium(II) ions from sulphate solution has been studied. The solutions of Ni(II) and Cd(II) have been treated with different exchange resins: Lewatit OC-1026, Lewatit TP-207, and Lewatit MonoPlus SP 112. Data obtained from the ion-exchange process was compared with data from the supported liquid membrane experiment. It was shown that the use of the supported liquid

Paulina Otrembska; Jerzy G?ga

2012-01-01

260

A kinetic model for ion exchange between cesium and sodium using silico-titanates  

E-print Network

A KINETIC MODEL FOR ION EXCHANGE BETWEEN CESIUM AND SODIUM USING SILICO-TITANATES A Thesis by LUAN THANH NGUYEN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... Kinetic Model for Ion Exchange Between Cesium and Sodium Using Silico-Titanates. (December 1994) Luan Thanh Nguyen, B. S. in Chemical Engineering, University of Houston; M. S, in Applied Mathematics, University of Houston Chair of Advisory Committee...

Nguyen, Luan Thanh

2012-06-07

261

Multifunctional ion-exchange stationary phases for high-performance liguid chromatography  

Microsoft Academic Search

The preparation and properties of multifunctional ion-exchangers, including one cation and two zwitterion types, for high-performance liquid chromatography (HPLC) are described. These ion-exchange stationary phases (IXSPs) were synthesized through two major steps; first by bonding the corresponding organic moieties, either undecenoic acid, aniline or ethyl p-fluorobenzoate, onto silica surfaces with appropriate silane coupling agents. The bonded silica was subsequently derivatized

Mei-Hui Yang; Kuo-Chang Chang; Jer-Yann Lin

1996-01-01

262

An exploratory program for using hydrous metal oxide ion exchangers as Fischer-Tropsch catalysts  

Microsoft Academic Search

The purpose of this program is to investigate the potential of hydrous metal oxide (HMO) ion exchangers, invented at Sandia National Laboratories, as Fischer-Tropsch (F-T) catalysts. Metals known to be active in F-T synthesis (e.g. Fe, Co) were ion exchanged on hydrous metal oxide supports. Although HMO catalysts based on Zr, Nb, and Ta have been investigated in direct coal

A. W. Lynch; R. G. Dosch; A. G. Sault

1990-01-01

263

A priori prediction of adsorption isotherm parameters and chromatographic behavior in ion-exchange systems  

Microsoft Academic Search

The a priori prediction of protein adsorption behavior has been a long-standing goal in several fields. In the present work, property-modeling techniques have been used for the prediction of protein adsorption thermodynamics in ion-exchange systems directly from crystal structure. Quantitative structure-property relationship models of protein isotherm parameters and Gibbs free energy changes in ion-exchange systems were generated by using a

Asif Ladiwala; Kaushal Rege; Curtis M. Breneman; Steven M. Cramer

2005-01-01

264

Management of Spent Organic Ion-Exchange Resins by Photochemical Oxidation  

Microsoft Academic Search

Management of spent ion-exchange resin waste arising from nuclear reactor operations by traditional practice of encapsulation in cement is associated with problems such as swelling and disintegration. Complete oxidation (mineralization) is an attractive alternative option. This paper reports the development of photochemical mineralization process for organic ion-exchange resins of poly (styrene-divinyl benzene) type with sulfonic acid and quaternary ammonium functional

C. Srinivas; S. Sugilal; P. K. Wattal

2003-01-01

265

Application of ion-exchange to mass spectrometric determination of boron in mineral waters  

Microsoft Academic Search

Summary The mass spectrometric stable isotope dilution technique has been applied to the determination of boron in mineral waters. Highly enriched10B in the form of H3BO3 was added to the mineral water sample as a spike and the boron (as H3BO3) was separated from strong electrolytes by ion-exchange (Dowex 50 W-X 8 and Dowex 3). Boric acid from the ion-exchange

B. Gorenc; J. Marsel; G. Tramšek

1970-01-01

266

THERMAL PERFORMANCE ANALYSIS FOR SMALL ION-EXCHANGE CESIUM REMOVAL PROCESS  

Microsoft Academic Search

The In-Riser Ion Exchange program focuses on the development of in-tank systems to decontaminate high level waste (HLW) salt solutions at the Savannah River Site (SRS) and the Hanford Site. Small Column Ion Exchange (SCIX) treatment for cesium removal is a primary in-riser technology for decontamination prior to final waste immobilization in Saltstone. Through this process, radioactive cesium from the

S. Lee; W. King

2009-01-01

267

Optical waveguides Me:LiTaO3 prepared by nonisovalent ion exchange  

Microsoft Academic Search

A new method to form optical waveguides in lithium tantalate crystals, the nonisovalent ion exchange in the salt melts, is proposed. We found that the waveguides can be formed by ion exchange reactions Zn ? 2Li, Ni ? 2Li, Mn ? 2Li, Fe ? 2Li, Co ? 2Li, Ca ? 2Li, Mg ? 2Li in the melts of mixtures K2SO4—Na2SO4—Li2SO4—MeSO4

V. A. Fedorov; V. A. Ganshin; Yu. N. Korkishko; T. V. Morozova

1993-01-01

268

Assessment of commercially available ion exchange materials for cesium removal from highly alkaline wastes  

SciTech Connect

Approximately 61 million gallons of nuclear waste generated in plutonium production, radionuclide removal campaigns, and research and development activities is stored on the Department of Energy`s Hanford Site, near Richland, Washington. Although the pretreatment process and disposal requirements are still being defined, most pretreatment scenarios include removal of cesium from the aqueous streams. In many cases, after cesium is removed, the dissolved salt cakes and supernates can be disposed of as LLW. Ion exchange has been a leading candidate for this separation. Ion exchange systems have the advantage of simplicity of equipment and operation and provide many theoretical stages in a small space. The organic ion exchange material Duolite{trademark} CS-100 has been selected as the baseline exchanger for conceptual design of the Initial Pretreatment Module (IPM). Use of CS-100 was chosen because it is considered a conservative, technologically feasible approach. During FY 96, final resin down-selection will occur for IPM Title 1 design. Alternate ion exchange materials for cesium exchange will be considered at that time. The purpose of this report is to conduct a search for commercially available ion exchange materials which could potentially replace CS-100. This report will provide where possible a comparison of these resin in their ability to remove low concentrations of cesium from highly alkaline solutions. Materials which show promise can be studied further, while less encouraging resins can be eliminated from consideration.

Brooks, K.P.; Kim, A.Y.; Kurath, D.E.

1996-04-01

269

Modeling a novel ion exchange process for arsenic and nitrate removal  

Microsoft Academic Search

Arsenate and nitrate can be removed quantitatively from drinking water by anion exchange. However, if the raw water contains substantial concentrations of sulfate or nitrate, the resin becomes exhausted quickly, and the requirements for regenerant (brine) can make the process unattractive. Previously, we described a modified ion exchange operating procedure for arsenic removal from solutions containing sulfate that could overcome

Jaeshin Kim; Mark M Benjamin

2004-01-01

270

Current status of ion exchange membranes for power generation from salinity gradients  

Microsoft Academic Search

Reverse electrodialysis (RED) is a non-polluting, sustainable technology used to generate energy by mixing water streams with different salinity. The key components in a RED system are the ion exchange membranes. This paper evaluates the potential of commercially available anion and cation exchange membranes for application in RED. Different membrane properties and characterization methods are discussed and a theoretical membrane

Piotr D?ugo??cki; Kitty Nymeijer; Sybrand Metz; Matthias Wessling

2008-01-01

271

Chloride\\/sulfate ion exchange kinetics on fibrous resins. Two independent models for film diffusion control  

Microsoft Academic Search

Fibrous ion exchangers appear to be very promising for full scale applications in water conditioning (demineralization, softening), wastewater treatment for pollutant control, as well as for applications in new areas promoted by the physical structure of the materials. The kinetic performances of these exchangers appear to be faster than traditional bead-shaped resins. In a previous paper, the kinetic behavior of

Domenico Petruzzelli; G. Tiravanti; A. Kalinitchev; V. S. Soldatov

1995-01-01

272

Tentacle Ion Exchange Separation of Pb-NOM in Aquatic Systems  

E-print Network

exchanger for the separation of metal- organic species in natural freshwaters is investigated using admitted to be dominant, but it has been suggested (3, 4) that natural organic matter (NOM) competesTentacle Ion Exchange Separation of Pb-NOM in Aquatic Systems M . T A I L L E F E R T * A N D J

Taillefert, Martial

273

Combined ion exchange treatment for removal of dissolved organic matter and hardness  

Microsoft Academic Search

Dissolved organic matter (DOM) and hardness cations are two common constituents of natural waters that substantially impact water treatment processes. Anion exchange treatment, and in particular magnetic ion exchange (MIEX), has been shown to effectively remove DOM from natural waters. An important advantage of the MIEX process is that it is used as a slurry in a completely mixed flow

Jennifer N. Apell; Treavor H. Boyer

2010-01-01

274

Sorption kinetics of ammonia and ammonium ions on gel and macroporous sulphonic acid cation exchangers  

Microsoft Academic Search

Diffusion of ammonia and ammonium ions in sulphonic acid cation exchangers (gel Purolite SGC 100×10 MBH and macroporous Purolite C 160 MBH) from the solutions, representing the composition of “caustic condensate” (waste of nitrogen fertilizers production) is affected by pH of initial solution and structure of the matrix of cation exchanger. In gel matrix the effective intraparticle diffusivity (Def) depends

D. Kaušp?dien?; J. Snukiškis

2006-01-01

275

Recovery of Copper from Bioleaching Solutions of Waste Printed Circuit Boards Waste by Ion Exchange  

Microsoft Academic Search

According to the properties of bioleaching solutions of printed circuit boards (PCBs), copper in the leaching solution were recovery by ion exchange with macroporous styrene iminodiacetic acid chelating resin D401. The bed height of resin, flow rate, pH value on copper adsorption had been studied. Work Exchange Capacity (WEC) of copper increased with increasing bed height of resin and flow

Zhang Chenglong; Cai Yujia; Wang Jingwei; Bai Jianfeng; Zhou Yuan; Wu Wenjie; Mao Wenxiong

2010-01-01

276

OPERATING A SMALL FULL-SCALE ION EXCHANGE SYSTEM FOR URANIUM REMOVAL (JOURNAL VERSION)  

EPA Science Inventory

The design and operation of a small full-scale ion exchange system used to remove uranium from well water in the foothills west of Denver, Colorado, are described. Consistent removal of uranium was accomplished by anion exchange treatment at a reasonable cost. Because of a lack o...

277

Photosensitivity of ion-exchanged Er-doped phosphate glass using 248nm excimer laser radiation.  

PubMed

The photosensitivity to 248nm excimer laser radiation of Er-doped Schott IOG-1 phosphate glass is presented. The photosensitive mechanism is investigated by employing a grating recording process. Index changes of up to ~2.0x10(-3) were measured in silver ion-exchanged samples using diffraction efficiency measurements; whereas changes of only ~10(-5) were measured for non-ion-exchanged samples. Absorption measurements allowed the identification of specific color center bands, which were attributed to the glass matrix and to the silver ions. Investigation of the exposed ion-exchanged glass using scanning electron microscopy and energy dispersive x-ray microanalysis revealed that in addition to the color centers formed, silver ion migration and ionization contribute significantly to the UV-induced index changes. PMID:19483833

Pissadakis, Stavros; Ikiades, Aris; Hua, Ping; Sheridan, Anna; Wilkinson, James

2004-07-12

278

Combining Ion Mobility Spectrometry with Hydrogen-Deuterium Exchange and Top-Down MS for Peptide Ion Structure Analysis.  

PubMed

The gas-phase conformations of electrosprayed ions of the model peptide KKDDDDIIKIIK have been examined by ion mobility spectrometry (IMS) and hydrogen deuterium exchange (HDX)-tandem mass spectrometry (MS/MS) techniques. [M+4H](4+) ions exhibit two conformers with collision cross sections of 418 Å(2) and 471 Å(2). [M+3H](3+) ions exhibit a predominant conformer with a collision cross section of 340 Å(2) as well as an unresolved conformer (shoulder) with a collision cross section of ~367 Å(2). Maximum HDX levels for the more compact [M+4H](4+) ions and the compact and partially-folded [M+3H](3+) ions are ~12.9, ~15.5, and ~14.9, respectively. Ion structures obtained from molecular dynamics simulations (MDS) suggest that this ordering of HDX level results from increased charge-site/exchange-site density for the more compact ions of lower charge. Additionally, a new model that includes two distance calculations (charge site to carbonyl group and carbonyl group to exchange site) for the computer-generated structures is shown to better correlate to the experimentally determined per-residue deuterium uptake. Future comparisons of IMS-HDX-MS data with structures obtained from MDS are discussed with respect to novel experiments that will reveal the HDX rates of individual residues. PMID:25267084

Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Maleki, Hossein; Arndt, James R; Donohoe, Gregory C; Valentine, Stephen J

2014-12-01

279

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2013 CFR

...to remove undesirable ions or to replace less desirable ions with one or more of the following: bicarbonate, calcium, carbonate, chloride, hydrogen, hydroxyl, magnesium, potassium, sodium, and sulfate except that: The...

2013-04-01

280

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2012 CFR

...to remove undesirable ions or to replace less desirable ions with one or more of the following: bicarbonate, calcium, carbonate, chloride, hydrogen, hydroxyl, magnesium, potassium, sodium, and sulfate except that: The...

2012-04-01

281

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2011 CFR

...to remove undesirable ions or to replace less desirable ions with one or more of the following: bicarbonate, calcium, carbonate, chloride, hydrogen, hydroxyl, magnesium, potassium, sodium, and sulfate except that: The...

2011-04-01

282

21 CFR 173.25 - Ion-exchange resins.  

...to remove undesirable ions or to replace less desirable ions with one or more of the following: bicarbonate, calcium, carbonate, chloride, hydrogen, hydroxyl, magnesium, potassium, sodium, and sulfate except that: The...

2014-04-01

283

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2010 CFR

...to remove undesirable ions or to replace less desirable ions with one or more of the following: bicarbonate, calcium, carbonate, chloride, hydrogen, hydroxyl, magnesium, potassium, sodium, and sulfate except that: The...

2010-04-01

284

Ion-exchange material and method of storing radioactive wastes  

DOEpatents

A new cation exchanger is a modified tobermorite containing aluminum isomorphously substituted for silicon and containing sodium or potassium. The exchanger is selective for lead, rubidium, cobalt, and cadmium and is selective for cesium over calcium or sodium. The tobermorites are compatible with cement and are useful for the long-term fixation and storage of radioactive nuclear wastes.

Komarneni, S.; Roy, D.M.

1983-10-31

285

Antimicrobial properties of zeolite-X and zeolite-A ion-exchanged with silver, copper, and zinc against a broad range of microorganisms.  

PubMed

Zeolites are nanoporous alumina silicates composed of silicon, aluminum, and oxygen in a framework with cations, water within pores. Their cation contents can be exchanged with monovalent or divalent ions. In the present study, the antimicrobial (antibacterial, anticandidal, and antifungal) properties of zeolite type X and A, with different Al/Si ratio, ion exchanged with Ag(+), Zn(2+), and Cu(2+) ions were investigated individually. The study presents the synthesis and manufacture of four different zeolite types characterized by scanning electron microscopy and X-ray diffraction. The ion loading capacity of the zeolites was examined and compared with the antimicrobial characteristics against a broad range of microorganisms including bacteria, yeast, and mold. It was observed that Ag(+) ion-loaded zeolites exhibited more antibacterial activity with respect to other metal ion-embedded zeolite samples. The results clearly support that various synthetic zeolites can be ion exchanged with Ag(+), Zn(2+), and Cu(2+) ions to acquire antimicrobial properties or ion-releasing characteristics to provide prolonged or stronger activity. The current study suggested that zeolite formulations could be combined with various materials used in manufacturing medical devices, surfaces, textiles, or household items where antimicrobial properties are required. PMID:24242073

Demirci, Selami; Ustao?lu, Zeynep; Y?lmazer, Gonca Alt?n; Sahin, Fikrettin; Baē, Nurcan

2014-02-01

286

CHARACTERIZATION OF CYCLED SPHERICAL RESORCINOL-FORMALDEHYDE ION EXCHANGE RESIN  

SciTech Connect

This report presents characterization data for two spherical resorcinol-formaldehyde (sRF) resin beds that had processed cesium in non-radioactive and radioactive cycles. All column cycle operations for the resin beds including loading, displacements, elution, regeneration, breakthroughs, and solution analyses are reported in Nash and Duignan, 2009a. That report covered four ion exchange (IX) campaigns using the two {approx}11 mL beds in columns in a lead-lag arrangement. The first two campaigns used Savannah River Site (SRS) Tank 2F nonradioactive simulant while the latter two were fed with actual dissolved salt in the Savannah River National Laboratory (SRNL) Shielded Cells. Both radioactive cycles ran to cesium breakthrough of the lead column. The resin beds saw in excess of 400 bed volumes of feed in each cycle. Resin disposal plans in tank farm processing depend on characterizations of resin used with actual tank feed. Following a final 30 bed volume (BV) elution with nitric acid, the resin beds were found to contain detectable chromium, barium, boron, aluminum, iron, sodium, sulfur, plutonium, cesium, and mercury. Resin affinity for plutonium is important in criticality safety considerations. Cesium-137 was found to be less than 10E+7 dpm/g of resin, similar to past work with sRF resin. Sulfur levels are reasonably consistent with other work and are expected to represent sulfur chemistry used in the resin manufacture. There were low but detectable levels of technetium, americium, and curium. Toxicity Characteristic Leaching Procedure (TCLP) work on the used (eluted) resin samples showed significant contents of mercury, barium, and chromium. One resin sample exceeded the TCLP level for mercury while the other metals were below TCLP levels. TCLP organics measurements indicated measurable benzene in one case, though the source was unknown. Results of this work were compared with other work on similar sRF resin characterizations in this report. This is the first work to quantify mercury on sRF resin. Resin mercury content is important in plans for the disposition of used sRF resin. Mercury speciation in high level waste (HLW) is unknown. It may be partly organic, one example being methyl mercury cation. Further study of the resin's affinity for mercury is recommended.

Nash, C.; Duignan, M.

2010-02-23

287

ROTARY FILTER FINES TESTING FOR SMALL COLUMN ION EXCHANGE  

SciTech Connect

SRNL was requested to quantify the amount of 'fines passage' through the 0.5 micron membranes currently used for the rotary microfilter (RMF). Testing was also completed to determine if there is any additional benefit to utilizing a 0.1 micron filter to reduce the amount of fines that could pass through the filter. Quantifying of the amount of fines that passed through the two sets of membranes that were tested was accomplished by analyzing the filtrate by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) for titanium. Even with preparations to isolate the titanium, all samples returned results of less than the instrument's detection limit of 0.184 mg/L. Test results show that the 0.5 micron filters produced a significantly higher flux while showing a negligible difference in filtrate clarity measured by turbidity. The first targeted deployment of the RMF is with the Small Column Ion Exchange (SCIX) at the Savannah River Site (SRS). SCIX uses crystalline silicotitanate (CST) to sorb cesium to decontaminate a clarified salt solution. The passage of fine particles through the filter membranes in sufficient quantities has the potential to impact the downstream facilities. To determine the amount of fines passage, a contract was established with SpinTek Filtration to operate a 3-disk pilot scale unit with prototypic filter disk and various feeds and two different filter disk membranes. SpinTek evaluated a set of the baseline 0.5 micron filter disks as well as a set of 0.1 micron filter disks to determine the amount of fine particles that would pass the membrane and to determine the flux each set produced. The membrane on both disk sets is manufactured by the Pall Corporation (PMM 050). Each set of disks was run with three feed combinations: prototypically ground CST, CST plus monosodium titanate (MST), and CST, MST, plus Sludge Batch 6 (SB6) simulant. Throughout the testing, samples of the filtrate were collected, measured for turbidity, and sent back to SRNL for analysis to quantify the amount of fines that passed through the membrane. It should be noted that even though ground CST was tested, it will be transferred to the Defense Waste Processing Facility (DWPF) feed tank and is not expected to require filtration.

Herman, D.

2011-08-03

288

Ion exchange selectivity for cross-linked polyacrylic acid  

NASA Technical Reports Server (NTRS)

The ion separation factors for 21 common metal ions with cross-linked polyacrylic acid were determined as a function of pH and the percent of the cross-linked polyacrylic acid neutralized. The calcium ion was used as a reference. At a pH of 5 the decreasing order of affinity of the ions for the cross-linked polyacrylic acid was found to be: Hg++, Fe+++, Pb++, Cr+++, Cu++, Cd++, Al+++, Ag+, Zn++, Ni++, Mn++, Co++, Ca++, Sr++, Ba++, Mg++, K+, Rb+, Cs+, Na+, and Li+. Members of a chemical family exhibited similar selectivities. The Hg++ ion appeared to be about a million times more strongly bound than the alkali metal ions. The relative binding of most of the metal ions varied with pH; the very tightly and very weakly bound ions showed the largest variations with pH. The calcium ion-hydrogen ion equilibrium was perturbed very little by the presence of the other ions. The separation factors and selectivity coefficients are discussed in terms of equilibrium and thermodynamic significance.

May, C. E.; Philipp, W. H.

1983-01-01

289

Advanced Ion Exchange Softening. Training Module 2.212.4.77.  

ERIC Educational Resources Information Center

This document is an instructional module package prepared in objective form for use by an instructor familiar with the operation of an ion exchange softening system. It includes objectives, an instructor guide, student handouts and transparency masters. This is the third level of a three module series. This module considers the theory of ion…

McMullen, L. D.

290

Electrodialysis versus ion exchange: comparison of the cumulative energy demand by means of two applications  

Microsoft Academic Search

The aim of the present paper is the comparison of electrodialysis (ED) and ion exchange (IE) with regard to their cumulative energy demand by means of two applications separating ions with significantly different molar weight. Data for the separation of sodium gluconate and for the desalination of whey are obtained from laboratory experiments. Therefrom, a scale-up is done to an

Michael Greiter; Senad Novalin; Martin Wendland; Klaus-Dieter Kulbe; Johann Fischer

2004-01-01

291

Simulation of ion exchange water softening pretreatment for reverse osmosis desalination of brackish water  

Microsoft Academic Search

Prevention of membrane scaling in reverse osmosis (RO) desalination may require operation at low recoveries, which increases the amount of brine, increasing brine disposal costs and creating environmental hazard. Ion exchange (IEX) pretreatment removes Ca2+ and Mg2+ ions to limit scaling of salts. Use of concentrated water from RO process for regeneration of the IEX column eliminates the need for

Anand Venkatesan; Phillip C. Wankat

2011-01-01

292

Sodalite ion exchange in polyethylene oxide oligomer solvents Gina M. Canfield,a  

E-print Network

complexes that form with transition metal and rare earth cations. This can lead to the breakdown and rare earth ions. Ethylene oxide-based oligomers (polyethylene glycol, polyethylene glycol methyl ether to handle and not well-suited for aluminosilicate zeolites.5 Likewise, molten salt ion exchange (immersion

Latturner, Susan

293

Removal of lead (II) from aqueous environment by a fibrous ion exchanger: Polycinnamamide thorium (IV) phosphate  

Microsoft Academic Search

The objective of the present research was to synthesize, characterize and to investigate the removal efficiency of lead (II) ion from synthetic lead solution by a hybrid fibrous ion exchanger. In the present study polycinnamamide thorium (IV) phosphate was synthesized by co-precipitation method and was characterized using SEM, XRD, FTIR and TGA–DSC. To know the practical applicability, a detailed removal

Mahamudur Islam; Rajkishore Patel

2009-01-01

294

Water uptake and migration effects of electroactive ion-exchange polymer metal composite (IPMC) actuator  

Microsoft Academic Search

The low actuating voltage and quick bending responses of ion-exchange polymer metal composite (IPMC) are considered very attractive for the construction of various types of actuators and sensors. The principle of IPMC actuation under electric field has been believed to be the ion cluster flux and electro-osmotic drag of water from the anode to cathode direction through the hydrophilic channels

Jun Ho Lee; Jong Hoon Lee; Jae-Do Nam; Hyoukryeol Choi; Kwangmok Jung; Jae Wook Jeon; Young Kwan Lee; Kwang Jin Kim; Yongsug Tak

2005-01-01

295

Combined ion exchange treatment for removal of dissolved organic matter and hardness.  

PubMed

Dissolved organic matter (DOM) and hardness cations are two common constituents of natural waters that substantially impact water treatment processes. Anion exchange treatment, and in particular magnetic ion exchange (MIEX), has been shown to effectively remove DOM from natural waters. An important advantage of the MIEX process is that it is used as a slurry in a completely mixed flow reactor at the beginning of the treatment train. Hardness ions can be removed with cation exchange resins, although typically using a fixed bed reactor at the end of a treatment train. In this research, the feasibility of combining anion and cation exchange treatment in a single completely mixed reactor for treatment of raw water was investigated. The sequence of anion and cation exchange treatment, the number of regeneration cycles, and the chemistry of the regeneration solution were systematically explored. Simultaneous removal of DOM (70% as dissolved organic carbon) and hardness (>55% as total hardness) was achieved by combined ion exchange treatment. Combined ion exchange is expected to be useful as a pre-treatment for membrane systems because both DOM and divalent cations are major foulants of membranes. PMID:20117818

Apell, Jennifer N; Boyer, Treavor H

2010-04-01

296

Extraction of steroidal glucosideronic acids from aqueous solutions by anionic liquid ion-exchangers.  

PubMed

A pilot study on the extraction of three steroidal glucosiduronic acids from water into organic solutions of liquid ion-exchangers is reported. A single extraction of a 0.5mm aqueous solution of either 11-deoxycorticosterone 21-glucosiduronic acid or cortisone 21-glucosiduronic acid with 0.1m-tetraheptylammonium chloride in chloroform took more than 99% of the conjugate into the organic phase; under the same conditions, the very polar conjugate, beta-cortol 3-glucosiduronic acid, was extracted to the extent of 43%. The presence of a small amount of chloride, acetate, or sulphate ion in the aqueous phase inhibited extraction, but making the aqueous phase 4.0m with ammonium sulphate promoted extraction strongly. An increase in the concentration of ion-exchanger in the organic phase also promoted extraction. The amount of cortisone 21-glucosiduronic acid extracted by tetraheptylammonium chloride over the pH range of 3.9 to 10.7 was essentially constant. Chloroform solutions of a tertiary, a secondary, or a primary amine hydrochloride also will extract cortisone 21-glucosiduronic acid from water. The various liquid ion exchangers will extract steroidal glucosiduronic acid methyl esters from water into chloroform, although less completely than the corresponding free acids. The extraction of the glucosiduronic acids from water by tetraheptylammonium chloride occurs by an ion-exchange process; extraction of the esters does not involve ion exchange. PMID:5075264

Mattox, V R; Litwiller, R D; Goodrich, J E

1972-02-01

297

Ion temperatures in HIP-1 and SUMMA from charge-exchange neutral optical emission spectra  

NASA Technical Reports Server (NTRS)

Ion temperatures were obtained from observations of the H sub alpha, D sub alpha, and He 587.6 nm lines emitted from hydrogen, deuterium, and helium plasmas in the SUMMA and HIP-1 mirror devices at Lewis Research Center. Steady state discharges were formed by applying a radially inward dc electric field between cylindrical or annular anodes and hollow cathodes located at the peaks of the mirrors. The ion temperatures were found from the Doppler broadening of the charge-exchange components of spectral lines. A statistical method was developed for obtaining scaling relations of ion temperature as a function of current, voltage, and magnetic flux density. Derivations are given that take into account triangular monochromator slit functions, loss cones, and superimposed charge-exchange processes. In addition, the Doppler broadening was found to be sensitive to the influence of drift on charge-exchange cross section. The effects of finite ion-cyclotron radius, cascading, and delayed emission are reviewed.

Patch, R. W.; Lauver, M. R.

1976-01-01

298

Stability of phenol-formaldehyde ion-exchange sorbents in aqueous solutions  

NASA Astrophysics Data System (ADS)

It is shown that ion-exchange sorbents based on phenol-formaldehyde resins can be used for a long time for isolating and separating rare alkali metals without any significant changes in the ion-exchange selectivity and capacity. When the phenol sorbents were used in alkaline solutions at elevated temperatures, carboxyl groups gradually accumulated in them as a result of the oxidation of methylol groups with oxygen dissolved in the solution. This led to a considerable increase in the ion-exchange capacity of the sorbents and a simultaneous decrease in the selectivity with respect to Cs+-Rb+ and Rb+-K+ ions (it is desirable to avoid the drying of phenol ionites in air by storing them in a swelled state in closed vessels).

Shelkovnikova, L. A.; Gavlina, O. T.; Ivanov, V. A.

2011-09-01

299

Biocompatibility Research of a Novel pH Sensitive Ion Exchange Resin Microsphere  

PubMed Central

The main objective of this study was to investigate biocompatibility and provide in-vivo pharmacological and toxicological evidence for further investigation of the possibility of pH sensitive ion exchange resin microsphere for clinical utilizations. Acute toxicity study and general pharmacological studies were conducted on the pH sensitive ion exchange resin microsphere we prepared. The general pharmacological studies consist of the effects of the pH sensitive ion exchange resin microsphere on the nervous system of mice, the functional coordination of mice, the hypnosis of mice treated with nembutal at subliminal dose, the autonomic activities of tested mice, and the heart rate, blood pressure, ECG and breathing of the anesthetic cats. The LD50 of pH sensitive ion exchange resin microsphere after oral administration was more than 18.84 g·Kg-1. Mice were orally administered with 16 mg·Kg-1, 32 mg·Kg-1 and 64 mg·Kg-1 of pH sensitive ion exchange resin microsphere and there was no significant influence on mice nervous system, general behavior, function coordination, hypnotic effect treated with nembutal at subliminal dose and frequency of autonomic activities. Within the 90 min after 5 mg·Kg-1, 10 mg·Kg-1, 20 mg·Kg-1 pH sensitive ion exchange resin microsphere was injected to cat duodenum, the heart rate, blood pressure, breathing and ECG of the cats didn’t make significant changes in each experimental group compared with the control group. The desirable pharmacological and toxicological behaviors of the pH sensitive ion exchange resin microsphere exhibited that it has safe biocompatibility and is possible for clinical use.

Liu, Hongfei; Shi, Shuangshuang; Pan, Weisan; Sun, Changshan; Zou, Xiaomian; Fu, Min; Feng, Yingshu; Ding, Hui

2014-01-01

300

Biocompatibility Research of a Novel pH Sensitive Ion Exchange Resin Microsphere.  

PubMed

The main objective of this study was to investigate biocompatibility and provide in-vivo pharmacological and toxicological evidence for further investigation of the possibility of pH sensitive ion exchange resin microsphere for clinical utilizations. Acute toxicity study and general pharmacological studies were conducted on the pH sensitive ion exchange resin microsphere we prepared. The general pharmacological studies consist of the effects of the pH sensitive ion exchange resin microsphere on the nervous system of mice, the functional coordination of mice, the hypnosis of mice treated with nembutal at subliminal dose, the autonomic activities of tested mice, and the heart rate, blood pressure, ECG and breathing of the anesthetic cats. The LD50 of pH sensitive ion exchange resin microsphere after oral administration was more than 18.84 g·Kg(-1). Mice were orally administered with 16 mg·Kg(-1), 32 mg·Kg(-1) and 64 mg·Kg(-1) of pH sensitive ion exchange resin microsphere and there was no significant influence on mice nervous system, general behavior, function coordination, hypnotic effect treated with nembutal at subliminal dose and frequency of autonomic activities. Within the 90 min after 5 mg·Kg(-1), 10 mg·Kg(-1), 20 mg·Kg(-1) pH sensitive ion exchange resin microsphere was injected to cat duodenum, the heart rate, blood pressure, breathing and ECG of the cats didn't make significant changes in each experimental group compared with the control group. The desirable pharmacological and toxicological behaviors of the pH sensitive ion exchange resin microsphere exhibited that it has safe biocompatibility and is possible for clinical use. PMID:25276183

Liu, Hongfei; Shi, Shuangshuang; Pan, Weisan; Sun, Changshan; Zou, Xiaomian; Fu, Min; Feng, Yingshu; Ding, Hui

2014-01-01

301

Selective separation of sodium ions from a mixture with phenylalanine by Donnan dialysis with a profiled sulfogroup cation exchange membrane  

NASA Astrophysics Data System (ADS)

The possibility of separating ions of metal from a mixture with ampholyte (an amino acid) by Donnan dialysis with an MK-40 sulfogroup cation exchange membrane is demonstrated. Conditions ensuring the selectivity and intensity of the mass transfer of sodium ions from a mixture with bipolar phenylalanine ions into a diffusate containing hydrochloric acid through a cation exchange membrane are found.

Vasil'eva, V. I.; Goleva, E. A.

2013-11-01

302

Synthesis, Characterization, and Applications of a New Ion Exchanger Tamarind 4-aminobenzoic Acid (TABA) Resin in Industrial Wastewater Treatment  

Microsoft Academic Search

Chromatographic column separations of toxic metal ions from industrial wastewater were achieved in acid media at optimized (Kd) values with a synthesized cation exchange TABA resin. The prepared TABA resin was characterized by FTIR, elemental, and thermogravimetric analysis. Studies of total ion exchange capacity, resin durability, and swelling were carried out. The distribution coefficient values of metal ions, viz Cu,

A. V. Singh; Naresh Kumar Sharma

2012-01-01

303

VizieR Online Data Catalog: Line ratios for helium-like ions (Porquet+, 2001)  

NASA Astrophysics Data System (ADS)

The tables include data concerning six He-like ions: wavelengths, transition probabilities, wavelengths at which the radiation temperatures should be determined. Line ratios (G and R, see definition in table 1 below) for six He-like ions from Tables 3 to 69 for various parameters: density (ne), temperature (Te), dilution factor (W), radiation temperature (Trad), and spectral resolution. Atomic data (appendix A) concerning the unresolved satellite lines are displayed (from Tables A1 to A6). (4 data files).

Porquet, D.; Mewe, R.; Dubau, J.; Raassen, A. J. J.; Kaastra, J. S.

2001-09-01

304

Radial stratification of ions as a function of mass to charge ratio in collisional cooling radio frequency multipoles used as ion guides or ion traps.  

PubMed

Collisional cooling in radio frequency (RF) ion guides has been used in mass spectrometry as an intermediate step during the transport of ions from high pressure regions of an ion source into high vacuum regions of a mass analyzer. Such collisional cooling devices are also increasingly used as 'linear', two-dimensional (2D) ion traps for ion storage and accumulation to achieve improved sensitivity and dynamic range. We have used the effective potential approach to study m/z dependent distribution of ions in the devices. Relationships obtained for the ideal 2D multipole demonstrate that after cooling the ion cloud forms concentric cylindrical layers, each of them composed of ions having the same m/z ratio; the higher the m/z, the larger is the radial position occupied by the ions. This behavior results from the fact that the effective RF focusing is stronger for ions of lower m/z, pushing these ions closer to the axis. Radial boundaries of the layers are more distinct for multiply charged ions, compared to singly charged ions having the same m/z and charge density. In the case of sufficiently high ion density and low ion kinetic energy, we show that each m/z layer is separated from its nearest neighbor by a radial gap of low ion density. The radial gaps of low ion population between the layers are formed due to the space charge repulsion. Conditions for establishing the m/z stratified structure include sufficiently high charge density and adequate collisional relaxation. These conditions are likely to occur in collisional RF multipoles operated as ion guides or 2D ion traps for external ion accumulation. When linear ion density increases, the maximum ion cloud radius also increases, and outer layers of high m/z ions approach the multipole rods and may be ejected. This 'overfilling' of the multipole capacity results in a strong discrimination against high m/z ions. A relationship is reported for the maximum linear ion density of a multipole that is not overfilled. PMID:11013419

Tolmachev, A V; Udseth, H R; Smith, R D

2000-01-01

305

The chemical precipitation of nickel on ion exchangers and active carbons  

NASA Astrophysics Data System (ADS)

The chemical precipitation of nickel in the form of poorly soluble precipitates in ion exchanger matrices and on active carbons from solutions of nickel chloride and chemical nickel plating electrolytes was studied. The sorption of nickel ions from a solution of nickel chloride occurs most effectively on Purolite D24002 macroporous chelate forming ion exchanger, KU-23-15/100 sulfo cation exchanger, and KU-2-8 gel sulfo cation exchanger. Nickel enters sulfo cation exchangers in the form of counterions, and is adsorbed on Purolite D24002 largely because of complex formation. The subsequent precipitation of nickel in the solid state in matrix pores liberates ionogenic centers, which allows repeated sorption cycles to be performed. After three chemical precipitation cycles under static conditions, the amount of nickel is higher by 170-250% than the ion exchange capacity of the sorbents. The electrolyte of chemical nickel plating contains nickel predominantly in the form of negatively charged and neutral complexes with glycine, which cannot form bonds with the matrices under study. It is therefore reasonable to perform sorption at decreased solution pH values.

Khorol'Skaya, S. V.; Zolotukhina, E. V.; Polyanskii, L. N.; Peshkov, S. V.; Kravchenko, T. A.; Krysanov, V. A.

2010-12-01

306

Antistick postpassivation of high-aspect ratio silicon molds fabricated by deep-reactive ion etching  

Microsoft Academic Search

High-aspect ratio (HAR) silicon molds formed with deep-reactive ion etching (DRIE) technique are difficult to use as masters for replication, especially for replication of high-aspect ratio microstructures. Microstructures in silicon molds made by DRIE have high surface energy and wavy vertical side walls, both of which make demolding difficult. In the research reported here, microstructured silicon master molds were made

J. X. Gao; L. P. Yeo; M. B. Chan-Park; J. M. Miao; Y. H. Yan; J. B. Sun; Y. C. Lam; C. Y. Yue

2006-01-01

307

Development of inorganic ion exchangers for nuclear waste remediation. 1997 annual progress report  

SciTech Connect

'In this research program, Oak Ridge National Laboratory (ORNL) is collaborating with Texas A and M University in the development of highly selective inorganic ion exchangers for the removal of cesium and strontium from nuclear tank-waste and from groundwater. Inorganic ion exchangers are developed and characterized at Texas A and M University; ORNL is involved in preparing the powders in engineered forms and testing the performance of the sorbents in actual nuclear waste solutions. The Texas A and M studies are divided into two main categories: (1) exchangers for tank wastes and (2) exchangers for groundwater remediation. These are subdivided into exchangers for use in acid and alkaline solutions for tank wastes and those that can be recycled for use in groundwater remediation. The exchangers will also be considered for in situ immobilization of radionuclides. The approach will involve a combination of exchanger synthesis, structural characterization, and ion exchange behavior. ORNL has developed a technique for preparing inorganic ion exchangers in the form of spherules by a gel-sphere internal gelation process. This technology, which was developed and used for making nuclear fuels, has the potential of greatly enhancing the usability of many other special inorganic materials because of the improved flow dynamics of the spherules. Also, pure inorganic spherules can be made without the use of binders. ORNL also has access to actual nuclear waste in the form of waste tank supernatant solutions for testing the capabilities of the sorbents for removing the cesium and strontium radionuclides from actual waste solutions. The ORNL collaboration will involve the preparation of the powdered ion exchangers, developed and synthesized at Texas A and M, in the form of spherules, and evaluating the performance of the exchangers in real nuclear waste solutions. Selected sorbents will be provided by Texas A and M for potential incorporation into microspheres, and the performance of the sorbents and microspheres will be examined using actual waste supernatant solutions. This collaborative program could potentially take an exchanger from concept, synthesis, structure determination, and elucidation of exchange mechanism, to engineered product and testing on real waste streams.'

Egan, B.Z.; Clearfield, A.; Collins, J.L.

1997-09-01

308

Transpiration efficiency over an annual cycle, leaf gas exchange and wood carbon isotope ratio of three tropical tree species  

E-print Network

Transpiration efficiency over an annual cycle, leaf gas exchange and wood carbon isotope ratio; published online August 6, 2009 Summary Variation in transpiration efficiency (TE) and its relationship. Cumulative transpiration was determined by repeatedly weighing the pots with a pallet truck scale. Dry matter

Bermingham, Eldredge

309

Online hydrogen/deuterium exchange performed in the ion mobility cell of a hybrid mass spectrometer.  

PubMed

The present paper describes the performance of online, gas-phase hydrogen/deuterium exchange implemented in the ion mobility cell of a quadrupole time-of-flight mass spectrometer. Deuterium oxide and deuterated methanol were utilized to create deuterated vapor that is introduced into the ion mobility region of the mass spectrometer. Hydrogen/deuterium exchange occurs spontaneously in the milliseconds time frame without the need of switching the instrument into ion mobility mode. The exchange was studied in case of low molecular weight molecules and proteins. The observed number of exchanged hydrogens was equal to the number of theoretically exchangeable hydrogens for all low molecular weight compounds. This method needs only minimal instrumental modifications, is simple, cheap, environment friendly, compatible with ultraperformance liquid chromatography, and can be implemented on commercially available instruments. It does not compromise choice of liquid chromatographic solvents and accurate mass or parallel-fragmentation (MS(E)) methods. The performance of this method was compared to that of conventional alternatives where the deuterated solvent is introduced into the cone gas of the instrument. Although the degree of exchange was similar between the two methods, the "cone gas method" requires 10 times higher deuterated solvent volumes (50 muL/min) and offers reduced sensitivity in the tandem mass spectrometry (MS/MS) mode. The presented method is suggested as a standard future element of mass spectrometers to aid online structural characterization of unknowns and to study conformational changes of proteins with hydrogen/deuterium exchange. PMID:19848411

Nagy, Kornél; Redeuil, Karine; Rezzi, Serge

2009-11-15

310

Tabulation and evaluation of ion exchange data on smectites, certain zeolites and basalt  

SciTech Connect

An extensive search of the literature has been made for ion exchange data on smectites, certain zeolites and basalt. The data are in the form of thermodynamic equilibrium constants, corrected selectivity coefficients, and distribution coefficients. Room temperature alkali and alkaline earth metal cation ion exchange data for smectites are extensive. Correlation between the exchange free energies of alkali metal cations on Camp Berteau montmorillonite values with their Debeye-Hueckel parameter was found. Significant differences in values of exchange constants for the same reaction on different smectites were noted. While this in part may be attributable to differences in experimental procedures, much of the variance is probably due to differences in charge densities and the effective field strengths of the smectites. Differences in field strength are related to the type and amount of substitution on intercrystalline octahedral and tetrahedral sites. Data on smectites suggest that cation exchange selectivities are very strong functions of temperature. Experiments on the exchange properties of clinoptilolite and mordenite have been generally confined to alkali and alkaline earth cations although data for certain transition metal ions are also available for synthetic mordenite. The temperature dependences of zeolite exchange selectivities remain largely unknown. Distribution coefficients for groundwater-basalt systems have been measured for a variety of elements at temperatures up to 150/sup 0/C. Steady state concentrations are often never achieved either from the sorption or the desorption side. Classical models of ion exchange have been applied successfully to zeolite and smectite exchange reactions. The sorption behavior of a basalt is better treated with models of the interface which take surface ionization and complexation into account.

Benson, L.V.

1980-05-01

311

Modeling Multi-Metal Ion Exchange in Biosorption  

E-print Network

by protonated Sargassum fluitans biomass in systems containing two metal ions and protons at different pH values by the brown alga Sargassum fluitans, which contains the carboxyl groups of alginate and the sulfate groups

Volesky, Bohumil

312

Development and Evaluation of Sustained Release Tablet of Betahistine Hydrochloride Using Ion Exchange Resin Tulsion T344  

PubMed Central

An attempt was made to sustain the release of Betahistine hydrochloride by complexation technique using strong cation-exchange resin, Tulsion T344. The drug loading onto ion-exchange resin was optimized for mixing time, activation, effect of pH, swelling time, ratio of drug?:?resin, and temperature. The resinate was evaluated for micromeritic properties and characterized using XRPD and IR. For resinate sustained release tablets were formulated using hydoxypropyl methylcellulose K100M. The tablets were evaluated for hardness, thickness, friability, drug content, weight variation, and in vitro drug release. Tablets thus formulated (Batch T-3) provided sustained release of drug over a period of 12?h. The release of Betahistine HCl from resinate controls the diffusion of drug molecules through the polymeric material into aqueous medium. Results showed that Betahistine HCl was formulated into a sustained dosage form as an alternative to the conventional tablet. PMID:22779010

Wagh, Vijay D.; Pawar, Nilesh

2012-01-01

313

Development and evaluation of sustained release tablet of betahistine hydrochloride using ion exchange resin tulsion t344.  

PubMed

An attempt was made to sustain the release of Betahistine hydrochloride by complexation technique using strong cation-exchange resin, Tulsion T344. The drug loading onto ion-exchange resin was optimized for mixing time, activation, effect of pH, swelling time, ratio of drug?:?resin, and temperature. The resinate was evaluated for micromeritic properties and characterized using XRPD and IR. For resinate sustained release tablets were formulated using hydoxypropyl methylcellulose K100M. The tablets were evaluated for hardness, thickness, friability, drug content, weight variation, and in vitro drug release. Tablets thus formulated (Batch T-3) provided sustained release of drug over a period of 12?h. The release of Betahistine HCl from resinate controls the diffusion of drug molecules through the polymeric material into aqueous medium. Results showed that Betahistine HCl was formulated into a sustained dosage form as an alternative to the conventional tablet. PMID:22779010

Wagh, Vijay D; Pawar, Nilesh

2012-01-01

314

Sorption of beryllium from fluorine-containing solutions by amino-phosphonate amphoteric ion-exchange resins  

SciTech Connect

Sorption of beryllium ions by a series of amino-phosphonate amphoteric ion-exchange resins from BeF/sub 2/ solutions containing HF, NH/sub 4/F.HF, and NH/sub 4/F has been studied. The influence of the salt form of the resin, concentration of fluoride ions, and beryllium content in the original solutions was demonstrated. The mechanism of ion exchange on amphoteric ion-exchangers was postulated on the basis of chemical analysis and sorption and IR-spectroscopic data. Conclusions are drawn regarding the participation of phosphorus-containing groups of the resins in exchange. Data are presented on desorption of complex fluoride ions and beryllium from amphoteric ion-exchange resins by solutions of hydrofluoric, hydrochloric, and sulfuric acids, ammonium fluoride, and ammonium hydrogenfluoride.

Pakholkov, V.S.; Rychkov, V.N.

1981-10-20

315

Properties of nickel-cadmium separators. [ion exchange membrances  

NASA Technical Reports Server (NTRS)

The thickness, moisture content, exchange capacity, tensile strength, diffusion characteristics, stability, and electrical properties are discussed for the 2291 radiation-grafted separator used in military vented nickel cadmium aircraft batteries. A regression analysis of separator resistance as a function of temperature and KOH concentration is included.

Lee, J.

1977-01-01

316

Preparation of catalysts via ion-exchangeable coatings on supports  

DOEpatents

Disclosed are: new catalytic compositions which comprise an inert support coated with a hydrous alkali metal, alkaline earth metal, or quaternary ammonium titanate, niobate, zirconate, or tantalate, in which the alkali or alkaline earth metal or quaternary ammonium cations have been exchanged for a catalytically effective quantity of a catalytically effective metal.

Dosch, R.G.; Stephens, H.P.

1986-04-09

317

AN EVALUATION OF MAGNETIC ION EXCHANGE (MIEX®) FOR NOM REMOVAL  

Microsoft Academic Search

A new process for the removal of natural organic matter (NOM) was developed in Australia by Orica Watercare and South Australian Water Corporation. It employs a strongly basic anion exchange resin to remove NOM from water. In the first stage of the process, the (180 µm) MIEX® resin is mixed with the water to be treated and its small size

Michael J. Semmens; M. Burckhardt; D. Schuler; P. Davich; M. Slunjski; M. Bourke; H. Nguyen; Orica Watercare Australia

318

NITRATE REMOVAL FROM WATER SUPPLIES BY ION EXCHANGE - EXECUTIVE SUMMARY  

EPA Science Inventory

Anion exchange using synthetic organic resins is a proven and practical technology for the removal of nitrate from water supplies. However, disposal of the spent regenerant brime solution containing nitrate is a potential problem. Two processes were examined in detail in this rep...

319

NITRATE REMOVAL FROM WATER SUPPLIES BY ION EXCHANGE  

EPA Science Inventory

Anion exchange using synthetic organic resins is a proven and practical technology for the removal of nitrate from water supplies. However, disposal of the spent regenerant brine solution containing nitrate is a potential problem. Two processes were examined in detail in this rep...

320

Charge exchange spectroscopy of multiply charged ions of industrial and astrophysical interest  

NASA Astrophysics Data System (ADS)

Photon emission spectra have been measured in collisions of multiply charged ions with neutral target gases in keV collision energies. Extreme ultra-violet emission spectra of Xe and Sn ions have contributed to give the atomic data for the understanding of the light source plasmas for the next generation semiconductor lithography. And soft X-ray emission spectra of highly charged O ions have related to the solar wind charge exchange, and the results have been regarded as the useful data for the understanding the collisions of the solar wind ions with the neutral matter within the heliosphere.

Tanuma, Hajime

2013-07-01

321

Charge exchange spectroscopy of multiply charged ions of industrial and astrophysical interest  

SciTech Connect

Photon emission spectra have been measured in collisions of multiply charged ions with neutral target gases in keV collision energies. Extreme ultra-violet emission spectra of Xe and Sn ions have contributed to give the atomic data for the understanding of the light source plasmas for the next generation semiconductor lithography. And soft X-ray emission spectra of highly charged O ions have related to the solar wind charge exchange, and the results have been regarded as the useful data for the understanding the collisions of the solar wind ions with the neutral matter within the heliosphere.

Tanuma, Hajime [Department of Physics, Tokyo Metropolitan University, 1-1 Minami-Ohsawa, Hachioji, Tokyo 192-0397 (Japan)

2013-07-11

322

Magnetic exchange interaction between rare-earth and Mn ions in multiferroic hexagonal manganites  

SciTech Connect

The authors report a study of magnetic dynamics in multiferroic hexagonal manganite HoMnO{sub 3} by far-infrared spectroscopy. Low-temperature magnetic excitation spectrum of HoMnO{sub 3} consists of magnetic-dipole transitions of Ho ions within the crystal-field split J = 8 manifold and of the triangular antiferromagnetic resonance of Mn ions. They determine the effective spin Hamiltonian for the Ho ion ground state. The magnetic-field splitting of the Mn antiferromagnetic resonance allows us to measure the magnetic exchange coupling between the rare-earth and Mn ions.

Talbayev, Diyar [Los Alamos National Laboratory; Trugman, Stuart A [Los Alamos National Laboratory; Taylor, Antoinette J [Los Alamos National Laboratory; Averitt, Richard D [Los Alamos National Laboratory; Namjung, Hur [INHA UNIV; Andrew, Laforge D [UCSD; Dimitri, Basov N [UCSD

2008-01-01

323

Structure simulation into a lamellar supramolecular network and calculation of the metal ions/ligands ratio  

PubMed Central

Background Research interest in phosphonates metal organic frameworks (MOF) has increased extremely in the last two decades, because of theirs fascinating and complex topology and structural flexibility. In this paper we present a mathematical model for ligand/metal ion ratio of an octahedral (Oh) network of cobalt vinylphosphonate (Co(vP)·H2O). Results A recurrent relationship of the ratio between the number of ligands and the number of metal ions in a lamellar octahedral (Oh) network Co(vP)·H2O, has been deducted by building the 3D network step by step using HyperChem 7.52 package. The mathematical relationship has been validated using X ray analysis, experimental thermogravimetric and elemental analysis data. Conclusions Based on deducted recurrence relationship, we can conclude prior to perform X ray analysis, that in the case of a thermogravimetric analysis pointing a ratio between the number of metal ions and ligands number around 1, the 3D network will have a central metal ion that corresponds to a single ligand. This relation is valid for every type of supramolecular network with divalent metal central ion Oh coordinated and bring valuable information with low effort and cost. PMID:22932493

2012-01-01

324

Ion-exchange and selectivity behavior of thermally treated and. gamma. -irradiated phases of zirconium(IV) arsenophosphate cation exchanger: separation of Al(III) from some metal ions and removal of cations from water  

SciTech Connect

Ion-exchange and selectivity behavior of zirconium(IV) arsenophosphate (ZAP) has been studied systematically after thermal and irradiation treatments. As a result, an increase in the ion-exchange capacity and a complete reversal in the selectivity sequence for some common metal ions has been observed on heating. The modified phase of ZAP has been utilized successfully for the quantitative separation of aluminum from numerous metal ions and for the removal of cations from water. 5 figures, 3 tables.

Varshney, K.G.; Varshney, K.; Agrawal, S.

1983-01-01

325

Modification of acid sites in ZSM-5 by ion-exchange: An in-situ FTIR study  

NASA Astrophysics Data System (ADS)

A study of the acid sites in Mn+-ZSM-5 zeolites (Mn+ = H+, Al3+, Ca2+, and Ba2+), synthesized by ion-exchange from the NH4+ form, has been carried out using X-ray diffraction, 27Al MAS NMR, and in-situ FTIR spectroscopy. X-ray diffraction data indicate that the crystalline structure of ZSM-5 is maintained on ion-exchange. 27Al MAS NMR spectroscopy confirms that Lewis acid sites in all of the Mn+-ZSM-5 zeolites are mainly located on the tetrahedral aluminum atoms in the zeolite framework. However, octahedral extra-framework aluminum is another source of Lewis acid sites in H+-ZSM-5 and Al3+-ZSM-5. Brųnsted acid sites are identified as originating from the hydroxyl groups that bridge Al and Si atoms. The acid sites in Mn+-ZSM-5 have been characterized by in-situ FTIR spectroscopy with pyridine as the probe molecule. FTIR spectroscopy demonstrated that the number of accessible acid sites and ratio of Lewis to Brųnsted acid sites in Mn+-ZSM-5 can be effectively modified by ion-exchange. The number of acid sites in Mn+-ZSM-5 increases in the same order as the acidity of cations with Ba2+ < Ca2+ < NH4+ < Al3+ < H+. Though the strength of both Lewis and Brųnsted acid sites is virtually identical for all Mn+-ZSM-5 zeolites, the ratio of Brųnsted to Lewis acid sites varies as a result of the loaded cation. In addition, modification of acid sites in Mn+-ZMS-5 by loading different cations is discussed in terms of the accessibility of the surface of the zeolite channels and the reactivity of the cations with Brųnsted acid hydroxyls. We conclude that larger cations can effectively constrict the zeolite channels and impede the ability of pyridine to access acid sites on the surface of the channels.

Wu, Weiqiang; Weitz, Eric

2014-10-01

326

Preliminary report on fractionation of fucans by ion-exchange displacement centrifugal partition chromatography.  

PubMed

A new method combining ion-exchange displacement chromatography with centrifugal partition chromatography (CPC) was used for the fractionation of partially depolymerized fucans (polysulphated polysaccharides). The ion-exchanger was Amberlite LA2, a high-molecular-mass liquid secondary amine miscible with most common organic solvents and immiscible with aqueous solutions. Ion-exchange displacement centrifugal partition chromatography was performed with LA2 in methyl isobutyl ketone (MiBK) as the stationary phase, water as the mobile phase, Cl- as the carrier and OH- as the displacer. A complex mixture of partially depolymerized fucans was resolved into adjacent families characterized by their peak molecular mass and polydispersity. The Dubois test (sugar) and the azur A test (SO3-) confirmed the displacement mode of the process, and size-exclusion chromatographic controls confirmed its efficiency. PMID:9544806

Chevolot, L; Colliec-Jouault, S; Foucault, A; Ratiskol, J; Sinquin, C

1998-02-27

327

Sorption of iron(III) from chromate solution by the aminocarboxylic ion exchanger ANKB-2  

SciTech Connect

The possibility of iron(III) sorption by the amphoteric ion exchanger ANKB-2 from chromate solution and its superiority over the cation exchanger KU-23 (10/60) have been demonstrated. By means of IR spectroscopy it has been shown that iron(III) sorption from chromate solution by ANKB-2 proceeds via both ionic and coordination reactions. The proportion of these kinds of reaction does not depend on the Cr(VI) content of the initial solution.

Stoyanova, O.F.; Izmailova, D.R.; Kurolap, N.S.; Uglyanskaya, V.A.

1986-12-20

328

Ion exchange equilibria of heavy metals in aqueous solution on new chelating resins of sporopollenin  

Microsoft Academic Search

Studies have been conducted on the sorption of several heavy metal ions Cu(II), Ni(II), Zn(II), Cd(II) and Al(III) from aqueous solutions on the new chelating exchangers of sporopollenin (Lycopodium clavatum) as a function of pH at several temperatures between 20 and 50°C. The novel metal-ligand exchange resins possessing oxime and carboxylic acid side arm functionality were prepared through the reaction

M. Ersoz; E. Pehlivan; H. J. Duncan; S. Yildiz; M. Pehlivan

1995-01-01

329

Ion exchange adsorption and elution for recovering gold thiosulfate from leach solutions  

Microsoft Academic Search

A new elution process for recovering gold thiosulfate from resins is described, and is based on the concept of synergistic ion exchange. In the presence of sulfite, Au(S2O3)23? is converted to Au(S2O3)(SO3)3?, which has a reduced affinity for strong anion exchange resins and is shown to be readily eluted by weaker eluants, such as chloride. Chloride has several advantages over

M. I. Jeffrey; D. M. Hewitt; X. Dai; S. D. Brunt

2010-01-01

330

Use of multi-transition-metal-ion-exchanged zeolite 13X catalysts in methane emissions abatement  

SciTech Connect

Methane is a potent greenhouse gas. It has a global warming potential (GWP) 23 times greater than carbon dioxide. Reducing methane emissions would lead to substantial economic and environmental benefits. This study investigated the performance of multi-transition-metal-(Cu, Cr, Ni, and Co)-ion-exchanged zeolite 13X catalysts in methane emissions abatement. The catalytic activity in methane combustion using multi-ion-exchanged catalysts was studied with different parameters including the molar percentage of metal loading, the space velocity, and the inlet methane concentration under atmospheric pressure and at a relatively low reaction temperature of 500 C. The performance of the catalysts was determined in terms of the apparent activation energy, the number of active sites of the catalyst, and the BET surface area of the catalyst. This study showed that multi-ion-exchanged catalysts outperformed single-ion-exchanged and acidified 13X catalysts and that lengthening the residence time led to a higher methane conversion percentage. The enhanced catalytic activity in the multi-ion-exchanged catalysts was attributed to the presence of exchanged transition ions instead of acid sites in the catalyst. The catalytic activity of the catalysts was influenced by the metal loading amount, which played an important role in affecting the apparent activation energy for methane combustion, the active sites, and the BET surface area of the catalyst. Increasing the amount of metal loading in the catalyst decreased the apparent activation energy for methane combustion and also the BET surface area of the catalyst. An optimized metal loading amount at which the highest catalytic activity was observed due to the combined effects of the various factors was determined. (author)

Hui, K.S.; Chao, C.Y.H.; Kwong, C.W.; Wan, M.P. [Department of Mechanical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

2008-04-15

331

Influence of ion/atom arrival ratio on structure and optical properties of AlN films by ion beam assisted deposition  

NASA Astrophysics Data System (ADS)

In order to improve the optical properties of AlN films, the influence of the ion/atom arrival ratio on the structure and optical characteristics of AlN films deposited by dual ion beam sputtering was studied by using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, spectroscopic ellipsometry and UV-vis spectroscopy. The films prepared at the ion/atom arrival ratio of 1.4 are amorphous while the crystalline quality is improved with the increase of the ion/atom arrival ratio. The films deposited at the ion/atom arrival ratio of no less than 1.8 have an approximately stoichiometric ratio and mainly consist of aluminum nitride with little aluminum oxynitride, while metallic aluminum component appears in the films deposited at the ion/atom arrival ratio of 1.4. When the ion/atom arrival ratio is not less than 1.8, films are smooth, high transmitting and dense. The films prepared with high ion/atom arrival ratio (?1.8) display the characteristic of a dielectric. The films deposited at the ion/atom arrival ratio of 1.4 are coarse, opaque and show characteristic of cermet.

Meng, Jian-ping; Fu, Zhi-qiang; Liu, Xiao-peng; Yue, Wen; Wang, Cheng-biao

2014-10-01

332

Optical waveguide fabricated by ion-exchange using stain method  

NASA Astrophysics Data System (ADS)

Optical waveguides were prepared by the incorporation of silver or copper ions using the classical staining. We used commercially available soda-lime silicate and borosilicate glasses as substrates. Silver or copper stain was applied on a side of the glass substrates. The substrates were heat-treated at elevated temperature for various times. The treated glasses were optically clear and almost colorless except for a few samples stained for longer time. This indicates that silver and copper metal nanoparticles and Cu2O nanoparticles causing coloration of glasses were not formed in the glass substrates. The ion-incorporation process was approximately controlled by the diffusion of ions. We observed the propagation of 633 nm laser radiation by a prism coupling method showing that the glass surface region plays a role of waveguide. Refractive index change more than 0.01 at 633 nm was achieved in the waveguide layers.

Kadono, Kohei; Suetsugu, Tatsuya; Ohtani, Takeshi; Kominami, Norimasa; Takada, Minoru; Einishi, Toshihiko; Tarumi, Takashi

2005-04-01

333

The cardiac Na+-Ca2+ exchanger has two cytoplasmic ion permeation pathways.  

PubMed

The Na(+)-Ca(2+) exchanger (NCX) is a ubiquitously expressed plasma membrane protein. It plays a fundamental role in Ca(2+) homeostasis by moving Ca(2+) out of the cell using the electrochemical gradient of Na(+) as the driving force. Recent structural studies of a homologous archaebacterial exchanger, NCX_Mj, revealed its outward configuration with two potential ion permeation pathways exposed to the extracellular environment. Based on the symmetry of NCX_Mj structure, an atomic model of an inward-facing conformation was generated showing similar pathways but directed to the cytoplasm. The presence of these water-filled cavities has yet to be confirmed experimentally, and it is unknown if the mammalian exchanger adopts the same structure. In this study, we mutated multiple residues within transmembrane segments 2 and 7 of NCX1.1 (cardiac isoform) to cysteines, allowing us to investigate their sensitivity to membrane-impermeable sulfhydryl reagents as exchanger current block. By trapping NCX1.1 in the inward-facing configuration, we have mapped two differently sized cytoplasmic aqueous cavities, the access of which is modified during exchange. This data reveals movements of the protein associated with ion transport. Electrophysiological characterization shows that the conserved residues within transmembrane segments 2 and 7, coordinating Na(+) and Ca(2+) ions in NCX_Mj, play a fundamental role in NCX1.1. Our results suggest a similar architecture between the mammalian and archaebacterial exchangers. PMID:23589872

John, Scott A; Liao, Jun; Jiang, Youxing; Ottolia, Michela

2013-04-30

334

Structure and ion exchange properties of tunnel type titanium silicates  

Microsoft Academic Search

A large number of titanium silicates are known to exist in the mineral realm and recently a considerable literature has developed concerned with the synthesis and properties of these and related compounds. This paper describes two such families that have tunnel structures filled with cations that may easily be exchanged. A sodium titanosilicate of ideal formula, Na2Ti2O3(SiO4)2·2H2O, is tetragonal and

Abraham Clearfield

2001-01-01

335

Building 579 waste ion exchange facility characterization report  

SciTech Connect

External direct surveys were performed for elevated {gamma} levels with a PG2 portable detector connected to a PRM 5-3 meter and for elevated {alpha} and {beta} levels with an NE portable detector. No {gamma} activity above background was detected. Several locations, the floor and west wall of building 579 and the manhole, had low levels of {beta} activity, up to 87 {+-} 49 dis/min. These values are below the allowable residual surface contamination limits for removable beta activity. There is water in the Mixed Bed Exchange Vessel, the Cation Exchange Vessel, the Closed Drain Tank, the manhole and some of the pipes. The accessible internal surfaces of the pipes, tanks and columns had higher levels of {beta} activity up to 172 {+-} 52 dis/min and some {alpha} activity up to 106 {+-} 29 dis/min. After the water is removed from the vessels, tanks, and lines, they should be surveyed to determine whether the areas accessible for smear surveys are representative of the general inside contamination levels. There are elevated levels of radionuclides in the resin from the Cation Exchange Vessel and in the water from the manhole. Since the radionuclide concentrations in the manhole water are less than ten times the site release criteria, it does not need any processing before it is released to the onsite drains. Although there are RCRA metals on the resin in the Cation Exchange Vessel, the amount that is removed during a leaching analysis is below the toxicity Characteristic level. Therefore, the resin is a radioactive waste not a mixed waste.

Sholeen, C.M.; Geraghty, D.C.

1997-03-01

336

Prediction of Gas Generation and Bubble Formation in Crystalline Silicotitanate Ion Exchange Columns  

SciTech Connect

Non-elutable ion exchange technology using crystalline silicotitanate (CST) has been studied at the Savannah River Site (SRS) for removing cesium from SRS soluble radioactive waste. The authors developed a transient model to describe the process of gas generation due to radiolysis and bubble formation in CST ion exchange (IX) columns using the Aspen Custom Modeler (ACM) software package. The model calculates gas concentrations and onset of bubble formation for large CST IX columns. The calculations include cesium loading as a function of time, gas generation as a function of cesium loading, and bubble formation as a function of gas solubility.

Hang, T.

2000-12-19

337

RESORCINOL-FORMALDEHYDE ION EXCHANGE RESIN CHEMISTRY FOR HIGH LEVEL WASTE TREATMENT  

SciTech Connect

A principal goal at the Savannah River Site is to safely dispose of the large volume of liquid nuclear waste held in many storage tanks. In-tank ion exchange technology is being considered for cesium removal using a polymer resin made of resorcinol formaldehyde that has been engineered into microspheres. The waste under study is generally lower in potassium and organic components than Hanford waste; therefore, the resin performance was evaluated with actual dissolved salt waste. The ion exchange performance and resin chemistry results are discussed.

Nash, C.; Duignan, M.

2010-01-14

338

Optical parametric amplification in composite polymer/ion exchanged planar waveguide  

NASA Astrophysics Data System (ADS)

A simple hybrid polymer/ion exchanged planar optical waveguiding structure has been fabricated which allows us to realize phase matching between different guided modes without any corrugation or modulation of the structure. A nonlinear polymer is deposited on top of glass substrate with a waveguide realized by the ion-exchange technique. Efficient optical parametric amplification is demonstrated for a pump at 532 nm and a signal at 814 nm. A 1 dB internal optical gain is achieved after propagation on 5 mm, with a pump power of 15 kW/mm.

Khalil, M. Alshikh; Vitrant, G.; Raimond, P.; Chollet, P. A.; Kajzar, F.

2000-12-01

339

Ion-exchange characteristics of sodium-calcium-silicate glass: Calculation from mode spectra  

NASA Astrophysics Data System (ADS)

The characteristics of silver-sodium ion exchange in standard commercial sodium-calcium-silicate glass are investigated using mode spectroscopy. The activation energy of the process, the silver-sodium interdiffusion coefficient, and the dependence of the maximal modulation of the refractive index on the silver nitrate concentration in the experimental salt bath are determined. The data set presented here makes it possible to specify the conditions for the formation of ion-exchange optical structures with preset parameters based on the glasses studied here.

Zhurikhina, V. V.; Petrov, M. I.; Sokolov, K. S.; Shustova, O. V.

2010-10-01

340

Comparison of some commercial and laboratory prepared caesium ion-exchangers  

NASA Astrophysics Data System (ADS)

This study was aimed at comparing options for 137Cs separation from a solution (240 g of sodium chloride and 10 g of potassium chloride in 1 L of distilled water) simulating the saline solution resulting from the treatment of a fast reactor primary coolant based on sodium and potassium. 137Cs distribution coefficients, sorption kinetics and sorption capacities of several commercial and laboratory preparations of inorganic ion-exchangers were compared. On the basis of the results obtained, the KNiFC-PAN composite ion-exchanger may be recommended as the most suitable for caesium separation from this type of solution.

Kamenķk, J.; ?ebesta, F.

2003-01-01

341

Solidphase nanoreactor based on calix[4]resorcinarene: Gel diffusion kinetics of ion exchange  

Microsoft Academic Search

A nanoreactor effect is found that consists in a considerable (two orders of magnitude) increase in the rate of ion exchange\\u000a in sulfonated calixarene-containing polymers. The kinetics of ion exchange in network calixarene-containing polymers with\\u000a sulfonic acid and phenolic ionogenic groups is studied. It is shown that the interaction of these polymers with aqueous solutions\\u000a of LiCl, NaCl, AgNO3, LiOH,

O. H. Altshuler; N. V. Malyshenko; G. J. Shkurenko; H. N. Altshuler

2009-01-01

342

Preparation and characterization of nano-ZnO flakes prepared by reactive ion exchange method  

Microsoft Academic Search

Nano-ZnO flakes were synthesized by calcination of the precursor of Zn(OH)2 obtained via the reactive ion exchange method between an ion exchange resin and ZnSO4 solution at room temperature. Scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscope, UV-Vis\\u000a diffuse reflection spectrum and Na2EDTA titration were used to characterize the structure features and chemical compositions of the as-prepared ZnO. The

Y. S. Li; G. Li; S. X. Wang; H. Gao; Z. C. Tan

2009-01-01

343

Ligand-exchange chromatography of aromatic amines on resin-bound cobalt ion  

SciTech Connect

The use of cobalt metal for the selective separation of aromatic amines is completed with a chemically bonded diamine and glyoxime functional groups onto Lycopodium clavatum. Oximes and amines are excellent complexing agents for transition metal ions. Cobalt(II) metal ions can easily be immobilized on bis-diaminoethyl-glyoximated sporopollenin (bDAEG-sporopollenin). The ligand-exchange behavior of modified Lycopodium clavatum with respect to aromatic amines was investigated. This will permit the evaluation of bDAEG-sporopollenin ligand exchangers for their utilization as sorbents in the recovery, pollution control, and elimination of amines from wastewater.

Pehlivan, E.; Vural, U.S.; Ayar, A.; Yildiz, S. [Selcuk Univ., Konya (Turkey)

1996-06-01

344

Channel waveguides on RbTiOPO4 by Cs+ ion exchange.  

PubMed

In this Letter we report Cs(+) ion exchange channel waveguides on RbTiOPO(4) (RTP) for what we believe is the first time. A Ti channel mask was fabricated on an RTP substrate by conventional photolithography. The ion exchange process was carried out in a CsNO(3) melt, and the channels produced ranged from 6 to 11 ?m in width. The near-field pattern of the modes was recorded, and type II second harmonic generation in waveguide regime was obtained, producing 512.5 nm green light. The optical characterization shows optical losses of 3.8 dB/cm. PMID:23381425

Cugat, J; Solé, R; Carvajal, J J; Mateos, X; Massons, J; Lifante, G; Dķaz, F; Aguiló, M

2013-02-01

345

Tagged hypervalent iodine reagents: a new purification concept based on ion exchange through SN2 substitution.  

PubMed

The preparation of phenylsulfonate-tagged iodine(III) reagents as well as their use in a novel purification strategy for iodine(III)-promoted reactions is described. The concept is based on ion exchange and is initiated by an azide-promoted SN2-reaction at the alkyl sulfonate followed by trapping of the resulting aryl sulfonate anion with an ion-exchange resin. The concept is successfully proven for Ru-catalyzed oxidations of alcohols, the activation and glycosidation of thioglycosides, and the SuArez reaction of pyranoses. PMID:17999512

Kunst, Eike; Gallier, Florian; Dujardin, Gilles; Yusubov, Mekhman S; Kirschning, Andreas

2007-12-01

346

Corrosion of steel drums containing cemented ion-exchange resins as intermediate level nuclear waste  

NASA Astrophysics Data System (ADS)

Exhausted ion-exchange resins used in nuclear reactors are immobilized by cementation before being stored. They are contained in steel drums that may undergo internal corrosion depending on the presence of certain contaminants. The objective of this work is to evaluate the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different aggressive species. The corrosion potential and the corrosion rate of the steel, and the electrical resistivity of the matrix were monitored for 900 days. Results show that the cementation of ion-exchange resins seems not to pose special risks regarding the corrosion of the steel drums. The corrosion rate of the steel in contact with cemented ion-exchange resins in the absence of contaminants or in the presence of 2.3 wt.% sulphate content remains low (less than 0.1 ?m/year) during the whole period of the study (900 days). The presence of chloride ions increases the corrosion rate of the steel at the beginning of the exposure but, after 1 year, the corrosion rate drops abruptly reaching a value close to 0.1 ?m/year. This is probably due to the lack of water to sustain the corrosion process. When applying the results obtained in the present work to estimate the corrosion depth of the steel drums containing the cemented radioactive waste after a period of 300 years, it is found that in the most unfavourable case (high chloride contamination), the corrosion penetration will be considerably lower than the thickness of the wall of the steel drums. Cementation of ion-exchange resins does not seem to pose special risks regarding the corrosion of the steel drums that contained them; even in the case the matrix is highly contaminated with chloride ions.

Duffó, G. S.; Farina, S. B.; Schulz, F. M.

2013-07-01

347

Ion exchange membrane textile bioreactor as a new alternative for drinking water denitrification.  

PubMed

This work enters in the optics of the denitrification of a polluted water by two membrane techniques, the Donnan dialysis (DD) and the ion exchange membrane bioreactor (IEMB), using a conventional barrier, composed by an anion exchange membrane (AEM), and a hybrid barrier, where the AEM is combined to an anion exchange textile (AET). The effects of the hydrodynamic factor and the nature of the carbon source on the transfer and the reduction of nitrate ions were studied. The study results obtained through the DD showed the effectiveness of the hybrid barrier in the recovery and concentration of nitrate ions. This was also recorded during denitrification by the hybrid process, called the ion exchange membrane textile bioreactor (IEMTB), with a significant reduction of nitrates, compared to IEMB, due to the efficiency of the Pseudomonas aeruginosa biofilm formed at the surface of the AET. Here, the permselectivity of the membrane and the good bioreduction of the pollutants are no longer major conditions to the better performance of the process. The application of IEMTB in the denitrification of groundwater, having a nitrate concentration of 96.67 ppm, shows a total reduction of nitrate ions without changing the quality of the water. Indeed, the analysis of the recovered water, or yet the treated water, shows the absence of the bacterium by-products and concentrations in the nitrates and nitrites which are, respectively, equal to 0.02±0.01 ppm, and inferiors to the detection limit (<0.02 ppm). PMID:24609773

Berdous, Dalila; Akretche, Djamal-Eddine; Abderahmani, Ahmed; Berdous, Sakina; Meknaci, Rima

2014-06-01

348

Small-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241-AN-103  

SciTech Connect

The pretreatment process for BNFL, Inc.'s Hanford River Protection Project is to provide decontaminated low activity waste and concentrated eluate streams for vitrification into low activity and high level waste glass, respectively. The pretreatment includes sludge washing, filtration, precipitation, and ion exchange processes to remove entrained solids, cesium, transuranics, technetium, and strontium. The ion exchange removal of cesium (Cs) and technetium (Tc) ions is accomplished by using SuperLig 644, and 639 resins from IBC Advanced Technologies, American Fork, Utah. The resins were shown to selectively remove cesium and technetium (as pertechnetate), from alkaline salt solutions. The efficiency of ion exchange column loading and elution is a complex function involving feed compositions, equilibrium and kinetic behavior of ion exchange resins, diffusion, and the ionic strength and pH of the aqueous solution. A previous experimental program completed at the Savannah River Technology Center demonstrated the conceptualized flow sheet parameters with a similar Hanford tank sample (241-AW-101). Those experiments included determination of Cs and Tc batch distribution coefficients by SuperLig 644 and 639 resins and demonstration of small-scale column breakthrough and elution. The experimental findings were used in support of preliminary design bases and pretreatment flow sheet development by BNFL, Inc.

Hassan, N.M.

2000-07-27

349

Denitration of Rocky Flats Ion-Exchange Resins: Recommendation of Denitration Processes, October 19, 1995  

SciTech Connect

Resin denitration via anion-exchange is an implementable process that can effectively mitigate the hazards associated with stored resins in which the bulk of the nitrate consists of an "exchangeable nitrate" ionically bound to the cationic sites of the anion-exchange resins. Salicylate has been selected as the exchange anion of choice because of its superior selectivity for the Rocky Flats resins and its unique potential for comprehensive recovery and recycle. This report outlines a single recommended resin denigration procedure that is reasonably independent of the resin composition and the current stored form. This procedure is not optimized but rather seeks to `over-treat' the resins so that a single procedure works for the variety of stored resins. The recommended treatment with sodium salicylate reduces resins by 95-99+% the measured exothermic behavior of the ion-exchange.

Jacob Espinoza; Mary Barr; Wayne Smith

1998-12-01

350

RADIOMETRIC EXTRACTION METHOD FOR FLUORIDE. PYROLYSIS-ION EXCHANGE SEPARATION  

Microsoft Academic Search

In many liquid-liquid extraction systems, complexing anions cause ; lowered extraction of metal ions. The potentiality of using this as the basis ; for determining anions has been investigated with the system hafnium-; fluoridetrioctylphosphine oxide. An inverse linear response was obtained for ; hafnium extraction vs. fluoride concentration for 2 to 10 mu moles of fluoride. ; Hafnium distribution is

W. J. Maeck; G. L. Booman; M. C. Elliott; J. E. Rein

1960-01-01

351

Absorption and luminescence of silver nanocomposite soda-lime glass formed by Ag +–Na + ion-exchange  

Microsoft Academic Search

Metal nanocomposite glasses are formed by a multi step methodology which involves incorporation of the metal ions into the glass by ion-exchange process followed by suitable treatments like low mass ion irradiation or thermal annealing resulting in the aggregation of the metal ions to form nano dimension metal clusters. These embedded metal nanoclusters are well investigated by the optical absorption

D. Manikandan; S. Mohan; K. G. M. Nair

2003-01-01

352

Sorption of beryllium from sulfate solutions by amino-carboxylic amphoteric ion-exchange resins (polyampholytes)  

SciTech Connect

In studies of sorption of beryllium ions from BeSO4 solutions by a series of aminocarboxylic polyampholytes the influence of pH and of the H2SO4, (NH4)2SO4, and BeSO4 concentrations was demonstrated. The mechanism of the process is postulated on the basis of sorption data and the results of IR-spectroscopic studies. It is concluded that carboxyl groups of polyampholytes take part in ion exchange.

Pakholkov, V.S.; Tsevin, A.P.; Rychkov, V.N.

1986-05-10

353

Retention behaviours and separation of carboxylic acids by ion-exchange chromatography  

Microsoft Academic Search

The use of high-performance suppressed ion chromatography for the separation of aliphatic carboxylic acids has become an attractive and viable method during the past years. This paper summarises and critically concludes that some new results have been achieved in separation and detection of low-molecular-mass organic anions. Theoretical and practical considerations of ion-exchange selectivity to control retention behaviour are presented. The

Peter Hajós; L??via Nagy

1998-01-01

354

Investigation of the adsorption and transport of natural organic matter (NOM) in ion-exchange membranes  

Microsoft Academic Search

The adsorption and transport characteristics of natural organic matter (NOM) in an ion-exchange (IX) membrane were investigated and the various methods to characterize the properties of NOM and the IX membrane were collectively evaluated in this study. NOM adsorption by an IX membrane is affected by both pH and ion strength. Under alkaline pH and low ionic strength, greater NOM

Do Hee Kim; Seung-Hyeon Moon; Jaeweon Cho

2003-01-01

355

Refractive index changes in proton exchange LiNbO 3 by ion implantation  

NASA Astrophysics Data System (ADS)

Ion implantation has been used to change the refractive index profile of proton exchanged LiNbO 3. Details of the index profile were determined by dark mode analysis. Changes induced by electronic and nuclear processes on x-cut crystals were separated. Comparisons are made with ion implantation profiles in pure LiNbO 3. Effects of thermal annealing to 150°C were recorded.

Glavas, E.; Townsend, P. D.; Foad, M. A.

1990-02-01

356

Separation of the lanthanides on high-efficiency bonded phases and conventional ion-exchange resins  

Microsoft Academic Search

High-performance liquid chromatographic separations (< 20 min) of the lanthanides are illustrated for both 5- and 10-..mu..m bonded-phase strong-acid ion exchangers. The performance of these bonded phase packings is compared with that obtained with a 13-..mu..m styrene-divinylbenzene resin. The eluted metal ions are detected with a variable-wavelength detector after a post-column complexation reaction. The requirements and characteristics of post-column reaction

S. Elchuk; R. M. Cassidy

1979-01-01

357

Ligand-Exchange Chromatography of Aromatic Amines on Resin-Bound Cobalt Ion  

Microsoft Academic Search

The use of cobalt metal for the selective separation of aromatic amines is completed with a chemically bonded diamine and glyoxime functional groups onto Lycopodium clavatum. Oximes and amines are excellent complexing agents for transition metal ions. Cobalt(II) metal ions can easily be immobilized on bis-diami-noethyl-glyoximated sporopollenin (bDAEG-sporopollenin). The ligand-exchange behavior of modified Lycopodium clavatum with respect to aromatic amines

Erol Pehlivan; Ufuk S. Vural; Ahmet Ayar; Salih Yildiz

1996-01-01

358

Effect of ion-to-electron mass ratio on the evolution of ion beam driven instability in particle-in-cell simulations  

NASA Astrophysics Data System (ADS)

In particle-in-cell (PIC) simulation studies of ion-ion two-stream instability, a reduced ion-to-electron mass ratio is often employed to save computation time. It is tacitly assumed that electrons do not play a significant role in the evolution of the instability as the ion-ion interactions are regarded to occur on time scales much slower than the response time of electrons. However, as the effect of such a reduced mass ratio has never been closely examined, we have studied the evolution of the ion beam driven instability using a one-dimensional electrostatic PIC code by rescaling the simulation parameters according to the ion-electron mass ratio. We made a reference simulation run with a mass ratio of 100 first and compared the results to the simulation results using the real mass ratio with parameters rescaled from those of the reduced mass ratio. External electric fields were applied in these simulations, which accelerated the electrons and excited an ion acoustic type instability, forming electron phase space holes. Merging of the electron holes affected the ion dynamics significantly when the reduced mass ratio was used, while the interplay between the electron and ion dynamics became different depending on the rescaling methods in the case of the real mass ratio. Another simulation test with much enhanced external electric field results in similar mass ratio dependence. The present simulation results clearly show that the reduced mass ratio should be used cautiously in PIC simulations as the electron dynamics can modify the ion instabilities significantly by affecting the ion motions.

Hong, Jinhy; Lee, Ensang; Min, Kyoungwook; Parks, George K.

2012-09-01

359

Experiments with an ion-neutral hybrid trap: cold charge-exchange collisions  

NASA Astrophysics Data System (ADS)

Due to their large trap depths (˜1 eV or 10,000 K), versatility, and ease of construction, Paul traps have important uses in high-resolution spectroscopy, plasma physics, and precision measurements of fundamental constants. An ion-neutral hybrid trap consisting of two separate but spatially concentric traps [a magneto-optic trap (MOT) for the neutral species and a mass-selective linear Paul trap for the ionic species] is an ideal apparatus for sympathetic cooling. However, over the past few years, hybrid traps have proven most useful in measuring elastic and charge-exchange rate constants of ion-neutral collisions over a wide temperature range from kilo-Kelvin to nano-Kelvin. We report some initially surprising results from a hybrid trap system in our laboratory where we have loaded the Paul trap with Ca+ ions in the presence of a Na MOT (localized dense gas of cold Na atoms). We find a strong loss of Ca+ ions with MOT exposure, attributed to an exothermic, non-resonant ion-neutral charge-exchange process with an activation barrier, which leads to the formation of Na+ ions. We propose a detailed mechanism for this process. We obtain an estimated measure of the rate constant for this charge exchange of ˜2 × 10-11 cm3/s, much less than the Langevin rate, which suggests that the Langevin assumption of unit efficiency in the reaction region is not correct in this case.

Smith, W. W.; Goodman, D. S.; Sivarajah, I.; Wells, J. E.; Banerjee, S.; Cōté, R.; Michels, H. H.; Mongtomery, J. A.; Narducci, F. A.

2014-01-01

360

Addition of acetic acid to styrene catalyzed by ion exchanger  

Microsoft Academic Search

The possibility of preparation of 1-phenylethyl acetate by direct addition of acetic acid to styrene catalyzed by Ostion KS in the acid cycle has been investigated. The reaction is accompanied by the formation of higher molecular compounds. The effect of temperature, mole ratio of the starting compounds, stabilization of styrene, amount of the catalyst and of its repeated use on

L. ?ervenż; A. Marhoul; J. Kozel

1988-01-01

361

Design of a Carousel Process for Removing Cesium from SRS Waste Using Crystalline Silicotitanate Ion Exchanger  

SciTech Connect

Designs of a three-column carousel process based on crystalline silicotitanate (CST) ion exchanger have been developed for removing radioactive 137Cs+ from Savannah River Site's (SRS) nuclear wastes. A multicomponent ion exchange equilibrium model (Zheng et al., 1997) from Texas A&M University, which is based on batch data obtained from CST powder, is used to generate cesium loading data at different cesium concentrations for various types of SRS wastes. These loading data are fit to the Langmuir equation to obtain effective single-component cesium isotherm parameters. The predictions are in reasonable agreement with batch test data obtained from CST powder, an early CST pellet batch (38B), and a later batch (IE911) using two SRS waste simulants. The ratios between experimental cesium distribution coefficients and predicted values are between 0.56 and 1.0. The variation appears to be due to inadequate equilibration time in some of the batches. Mass transfer parameters are estimated by analyzing column data of a simulated SRS waste and Melton Valley Storage Tank W29 (MVST-W29) waste. The intraparticle diffusivity estimated for the two wastes can be well correlated by means of the Stokes-Einstein equation.Simulations are performed to determine the length of the mass transfer zone for given feed compositions, Cs+ concentrations, and linear velocities. In order to ensure high column utilization during both the transient and cyclic steady state periods, the length of a single segment in the carousel process is chosen to be the mass transfer zone length after the concentration wave achieves a constant pattern. Analysis of the dimensionless groups in the differential mass balance equations reveals that the normalized mass transfer zone length is linearly proportional to the particle Peclet number. The proportionality constant is a function of the waste composition and the Cs+ concentration in the waste. The higher the effective Cs+ capacity and the higher the Cs+ concentration, the smaller the proportionality constant. This dimensionless group analysis allows one to easily adjust designs for variations in particle size, linear velocity, and intraparticle diffusivity.

Walker, D.D.

1999-01-15

362

Ion Exchange Recovery of Rhodium (III) from Chloride Solutions by Selective Anion Exchangers  

Microsoft Academic Search

The paper describes the results of a study of the recovery of rhodium (III) from chloride by sorption from strongly and weakly acidic solutions (2 M HCl and pH = 3) by macroreticular anion exchangers on the basis of methylacrylate and divinylsulfide as long-chained cross-linking agent. The initial concentration of Rh (III) in the contacting solution was 0.25–2.15 mmol\\/L, the

O. N. Kononova; E. L. Goncharova; A. M. Melnikov; D. M. Kashirin; A. G. Kholmogorov; S. G. Konontsev

2010-01-01

363

New ion exchangers and solvent extractants for pre-analysis separation of actinides. Annual report, June 1982May 1983  

Microsoft Academic Search

Prior to radiochemical determination of actinide elements such as uranium, neptunium and plutonium, an ion exchange or solvent extraction method is often employed to separate these from themselves and other interfering elements. In order to improve the separation efficiency and reduce time, cost, and liquid waste of analytical separation methods, new and better ion exchangers and solvent extractants are under

Navratil

1983-01-01

364

ION EXCHANGE IN THE ATOMIC ENERGY INDUSTRY WITH PARTICULAR REFERENCE TO ACTINIDE AND FISSION PRODUCT SEPARATION - A REVIEW  

Microsoft Academic Search

This paper reviews some of the uses of ion exchange processes by the nuclear industry for the period April 1978 to April 1983. The topics dealt with are: thorium, protactinium, uranium, neptunium, plutonium, americium, cesium and actinide-lanthanide separations; the higher actinides - Cm, Bk, Cf, Es and Fm; fission products; ion exchange in the geological disposal of radioactive waste. Consideration

I. L. Jenkins

1984-01-01

365

EVALUATION OF ION EXCHANGE TECHNOLOGY FOR TOXIC AND NON-CONVENTIONAL POLLUTANT REDUCTION IN BLEACH PLANT EFFLUENTS  

EPA Science Inventory

This research program was designed to evaluate the applicability of ion exchange technology in reducing the pollutional effects of pulp, paper, and paperboard bleach plant effluents. To gain some perspective on the state-of-the-art concerning ion exchange, a literature review was...

366

The Recovery of Iron from Zinc Sulphate-Sulphuric Acid Processing Solutions by Solvent Extraction or Ion Exchange  

Microsoft Academic Search

The technical literature on the solvent extraction and ion exchange recovery of iron from zinc sulphate-sulphuric acid processing media was reviewed to identify technologies which might lead to marketable iron products. The solvent extraction literature was reviewed from 1986 to the present, whereas all available information on the ion exchange route was surveyed. Although several extractants were identified that can

P. A. RIVEROS; J. E. DUTRIZAC; E. BENGUEREL; G. HOULACHI

1998-01-01

367

Use of Novel Highly Selective Ion Exchange Media for Minimizing the Waste Arising from Different NPP and Other Liquids  

Microsoft Academic Search

Highly selective inorganic ion exchangers give new possibilities to implement and operate new innovative treatment systems for radioactive liquids. Because of high selectivity these ion exchangers can be used even in liquids of high salt concentrations. Only selected target nuclides will be separated and inactive salts are left in the liquid, which can be released or recategorized. Thus, it is

Esko Tusa; Risto Harjula; Jukka Lehto

2003-01-01

368

SNL-1, a highly selective inorganic crystalline ion exchange material for Sr{sup 2+} in acidic solutions  

Microsoft Academic Search

A new inorganic ion exchange material, called SNL-1, has been prepared at Sandia National Laboratories. Developmental samples of SNL-1 have been determined to have high selectivity for the adsorption of Strontium from highly acidic solutions (1 M HNOā). This paper presents results obtained for the material in batch ion exchange tests conducted at various solution pH values and in the

T. M. Nenoff; S. G. Thoma; J. E. Miller; D. E. Trudell

1995-01-01

369

Dispersion of rhodium on rutile: Comparison of samples prepared by ion exchange and impregnation  

Microsoft Academic Search

Rh\\/TiO2 (rutile) samples have been prepared by impregnation (series I) and ion exchange (series C). Upon reduction at low temperature (473 K) the metal dispersity is larger for samples C than for samples I. Removal of surface OH groups in series C cancels the strong Metal-Support Interaction, thus increasing the metal dispersity measured upon reduction at 773 K.

M. J. Holgado; A. C. Ińigo; V. Rives

1992-01-01

370

The Effect of Hydrogen Peroxide on a CST Under Cesium Ion Exchange Conditions  

Microsoft Academic Search

About 10 years ago, a crystalline silicotitanate (CST) was synthesized using an alkali metal hydroxide and the alkoxides of titanium and silicon. TAM5 is a specific form of the developed CST. Later, TAM5 was modified by replacing about 25% of the titanium with niobium. The modified TAM5 was tested extensively to enable its use as an inorganic ion exchanger for

C. V. Philip; S. H. Kim; M. Philip; R. G. Anthony

2003-01-01

371

An Optimal Ion Exchange Design for Removal of Cesium from Hanford Waste  

SciTech Connect

Non-elutable crystalline silicotitanate (CST) ion-exchanger materials have been studied for removing cesium from a variety of radioactive wastes at several U.S. DOE sites over the last decade. For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP) in Hanford, the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based on SuperLig(R) 644 resin. However, due to concerns over potential radiological and chemical degradation of SuperLig(R) 644 resin, IONSIV IE-911 (CST in its engineered form) material is being proposed as a backup ion-exchange material for the removal of cesium from Hanford radioactive waste. This paper discusses the methodology used to determine the optimal CST ion-exchange column size to process all 16 separate batches of feeds from the ten targeted Hanford waste tanks. The optimal design ensures the best utilization of CST material and therefore results in a minimum amount of spent CST.

Hang, T.

2002-03-07

372

Basic Ion Exchange Softening. Training Module 2.210.2.77.  

ERIC Educational Resources Information Center

This document is an instructional module package prepared in objective form for use by an instructor familiar with ion exchange softening. It includes objectives, an instructor guide, student handouts, and transparency masters. This is the first level of a three module series. The module considers the principles, components, operation,…

McMullen, L. D.

373

Intermediate Ion Exchange Softening. Training Module 2.211.3.77.  

ERIC Educational Resources Information Center

This document is an instructional module package prepared in objective form for use by an instructor familiar with the operation of an ion exchange softening system. It includes objectives, an instructor guide, student handouts, and transparency masters. This is the second level of a three module series. The module considers operation and…

McMullen, L. D.

374

Femtosecond laser fabrication of Bragg gratings in borosilicate ion-exchange waveguides  

Microsoft Academic Search

Ultrafast 800-nm radiation from a Ti : sapphire amplifier was used to write high reflectivity Bragg gratings in silver ion-exchange waveguides made in a borosilicate glass substrate. The fabrication and visual\\/spectral characterization of the grating structures are presented. The measurements show low polarization effects in the grating spectral characteristics

Dan Grobnic; Stephen J. Mihailov; Christopher W. Smelser; Martin Becker; Manfred W. Rothhardt

2006-01-01

375

Integrated optics Bragg filters made by ion exchange and wafer bonding  

NASA Astrophysics Data System (ADS)

A polarization-insensitive Bragg filter has been realized on a glass substrate thanks to the epoxy-free wafer bonding technique. This device is based on the combined embedding of a corrugated grating and a surface ion-exchanged waveguide, both realized on a silicate glass. With this configuration, the grating patterns are also protected from external degradation of the environment.

Gardillou, F.; Bastard, L.; Broquin, J.-E.

2006-09-01

376

Reductive sorption of molecular oxygen from water by nanodisperse metals in an ion-exchanger matrix  

NASA Astrophysics Data System (ADS)

It is shown that the reduction of oxygen dissolved in water by metal (Ag, Cu, Bi, and Ni) — KU-23 ion exchanger nanocomposite can be inhibited by either internal diffusion or kinetic mechanisms, depending on the nature of the metal and its particle size.

Polyanskii, L. N.; Khorol'Skaya, S. V.; Kravchenko, T. A.; Peshkov, S. V.; Kipriyanova, E. S.; Starodubova, S. P.

2012-04-01

377

The state of water in different forms of sulfo ion-exchange fiber  

NASA Astrophysics Data System (ADS)

The state of water in the copper, zinc, and cobalt forms of VION KS-3 ion-exchange fiber is investigated by derivatography. The presence of differently bound water is found. For each step of water removal, hydration numbers of the fiber are determined. It is shown that the amount of water in the fiber depends on its ionic form.

Astapov, A. V.; Peregudov, Yu. S.; Kopylova, V. D.

2011-07-01

378

ARSENIC REMOVAL BY FULL SCALE ION EXCHANGE AND ACTIVATED ALUMINA TREATMENT  

EPA Science Inventory

This presentation discusses the results of a one year performance evaluation study of two ion exchange plants and two activated alumina plants that were designed and operated for the removal of arsenic from well water. All the plants were shown to be capable of reducing arsenic l...

379

Modeling ion-exchange adsorption of proteins in a spherical particle  

Microsoft Academic Search

This paper presents a simple model of single- and multicomponent protein adsorption in a spherical particle. The model includes radial diffusion of salt and protein in the liquid phase coupled to adsorption by an ion-exchange mechanism described by the steric mass action isotherm. The molecular diffusivities of the protein and salt are reduced in the model by a factor which

Stuart R Gallant

2004-01-01

380

Electron probe microanalysis of ion exchange of selected elements between dentine and adhesive restorative materials  

Microsoft Academic Search

Background: There have been numerous attempts to demonstrate the phenomenon of ion exchange between auto cure glass ionomer cements (GICs) and dentine. The purpose of this study was to employ an electron probe microanalysis (EPMA) technique to examine the interchange of elements between non-demineralized dentine and two types of restorative material, auto cure GICs and a resin composite. Methods: Restorations

GM Knight; JM McIntyre; GG Craig

2007-01-01

381

Ammonium removal from primary and secondary effluents using a bioregenerated ion-exchange process  

Microsoft Academic Search

A new process for ammonia removal from sewage effluents is presented. The process uses an ion exchange material, zeolite, both as the separator of NH4 + from the wastewater and also as the carrier for a nitrifying biomass. The process is carried out in a single reactor operating in two modes: an adsorption mode in which the zeolite column acts

O. Lahav; M. Green

382

Removal of Perfluorooctane and Perfluorobutane Sulfonate from Water via Carbon Adsorption and Ion Exchange  

Microsoft Academic Search

This research investigated the removal of perfluorooctane sulfonate (PFOS) and perfluorobutane sulfonate (PFBS) from water by Filtrasorb®400 granular activated carbon (GAC) and Amberlite®IRA-458 ion exchange resin. Kinetic experiments showed that the time required for the uptake equilibrium was ?50 hours for the GAC and ?10 hours for the resin. Sorption isotherms showed that PFOS and PFBS uptake was endothermic and

Kimberly E. Carter; James Farrell

2010-01-01

383

Removal of fluoride from spent pot liner leachate using ion exchange  

Microsoft Academic Search

Spent pot liner (SPL), a hazardous solid waste produced at cell houses of aluminum smelters, is a potential source of fluoride pollution. Leachates collected from SPL disposal sites were found to contain fluoride at considerable concentration levels. This paper reports a study of selective fluoride removal following laboratory-prepared, ion-exchange treatment. Spent pot liner leachates were pretreated with lime to bring

G. Singh; B. Kumar; P. K. Sen; J. Majumdar

1999-01-01

384

Conceptual study of in-tank cesium removal using an inorganic ion exchange material  

SciTech Connect

Presently, the Hanford Site contains approximately 230,000 m{sup 3} of mixed waste stored in 177 underground tanks. Approximately 55,000 m{sup 3} of this waste is sludge, 90,000 m{sup 3} is salt cake, and 80,000 m{sup 3} is supernate. Although the pretreatment and final disposal requirements for the waste have not been entirely defined, it is likely that some supernatant pretreatment will be required to remove {sup 137}Cs and possibly {sup 90}Sr and the transuranic components. The objective of this study was to estimate the number of HLW glass canisters resulting from the use of inorganic ion exchanger materials as in-tank pretreatment technology. The variables in the study were: number of contacts between waste and ion exchange material; ion exchange material; and decontamination requirement. This conceptual study investigates a generic in-tank Cs removal flowsheet using crystalline silico-titanates and IE-96 zeolites, and the impact of each ion exchanger on the number of glass canisters produced. In determining glass formulation, data based on current reference technology was used. Sample calculations from the worksheets and summaries of final calculated results are included at the end of this report.

Goheen, R.S.; Kurath, D.E.

1996-04-01

385

Extraction of phosphorus, potassium, calcium, and magnesium from soils by an ion?exchange resin procedure  

Microsoft Academic Search

A procedure for the simultaneous extraction of phosphorus, potassium, calcium and magnesium from soils, by an ion?exchange resin procedure applicable to large?scale advisory soil testing, is described. The important steps are the disaggregation of soil by shaking in water during 15 minutes with a glass marble, the transference of the elements from the soil to a sodium bicarbonate treated mixture

B. van Raij; J. A. Quaggio; N. M. da Silva

1986-01-01

386

WASTEWATER DEMINERALIZATION BY TWO-STAGE FIXED-BED ION EXCHANGE PROCESS  

EPA Science Inventory

A 9.5 l/min (2.5 gpm) two-stage fixed bed ion exchange process (primary cation - primary anion - secondary cation - secondary anion) was operated on a feed of carbon treated secondary effluent for 48 months at Pomona, California. To achieve high levels of regeneration efficiency ...

387

Removing Radium-226 Contamination From Ion Exchange Resins Used in Drinking Water Treatment  

E-print Network

Removing Radium-226 Contamination From Ion Exchange Resins Used in Drinking Water Treatment P r o b to remove naturally occurring radioactivity in groundwater limits the effectiveness to treat to drinking removal process during cleaning of resins with varying age and total cleaning cycles. M e t h o d o l o g

388

Evaluating Magnetic Ion Exchange Resin (MIEX)® Pretreatment to Increase Ozone Disinfection and Reduce Bromate Formation  

Microsoft Academic Search

Magnetic ion exchange resin, known by its commercial name (MIEX®) provides one pretreatment alternative that could maximize ozonation disinfection while decreasing bromate formation in bromide-containing waters. During a 5-week pilot study, the MIEX® process removed up to 30 % of the dissolved organic carbon (DOC) and reduced ultraviolet absorbance at 254 nm (UV 254) by up to 60%. When MIEX®

Eric C. Wert; Jessica C. Edwards-Brandt; Philip C. Singer; George C. Budd

2005-01-01

389

Dissolved organic matter removal and disinfection byproduct formation control using ion exchange  

Microsoft Academic Search

Three different ion exchange resins were evaluated for their ability to remove dissolved organic matter (DOM) and reduce formation of disinfection byproducts (DBPs) formed during chlorination of surface waters sampled from the Intercoastal Waterway, Myrtle Beach, SC, USA (MB water), and the Tomhannock Reservoir, Troy, NY, USA (TMK water). At resin doses up to 600 mg\\/L, DOC levels were reduced

Yongrui Tan; James E. Kilduff; Mehmet Kitis; Tanju Karanfil

2005-01-01

390

Removal of natural organic material by a magnetic ion exchange resin  

Microsoft Academic Search

The aim of this research was to elucidate the interactions among dissolved organic carbon (DOC), inorganic anions and a magnetic ion exchange (MIEX) resin. Model waters containing well characterised natural organic matter (NOM) extracts in addition to DOC-free model waters containing sulphate and bicarbonate were used in all experiments. The NOM extracts used in this work included two reference fulvic

T. H. Boyer; P. C. Singer

2008-01-01

391

Highly-selective and Regenerable Ion Exchange for Perchlorate Remediation, Recovery, and Environmental Forensics  

NASA Astrophysics Data System (ADS)

Perchlorate (ClO4-) has recently emerged as a widespread contaminant found in drinking water and groundwater supplies in the United States and is known to disrupt thyroid function by inhibiting iodide uptake. Among various treatment technologies, the highly-selective and regenerable ion-exchange technology has recently been developed at ORNL for removing ClO4- from contaminated water. The selective ion exchange technology relies on a unique, highly specific resin to trap ClO4- from contaminated water. The treatment system is then regenerated and perchlorate is destroyed. The reaction that destroys ClO4- produces Cl- and Fe(III) that are used to regenerate the resin, resulting in practically zero secondary waste production. In comparison with conventional non-selective ion-exchange technology, this new treatment process is expected to result in not only a reduced O&M cost but also the elimination of the disposal of hazardous wastes containing perchlorate. Additionally, the selective and regenerable ion exchange technology has allowed the quantitative recovery of perchlorate from contaminated water for reuse, or from other environmental matrices such as sediment, groundwater, and salt deposits for perchlorate isotopic and source identification. Naturally-forming perchlorate has been found to contain distinct oxygen and chlorine isotope signatures or anomalies as compared with anthropogenic perchlorate and can thus provide unambiguous identification of the sources of perchlorate contamination as a powerful tool for the forensics of perchlorate in the environment.

Gu, B.; Brown, G.

2007-12-01

392

Drug release from ion-exchange microspheres: mathematical modeling and experimental verification.  

PubMed

This paper presents for the first time a mathematical model for a mechanism of controlled drug release involving both ion exchange and transient counter diffusion of a drug and counterions. Numerical analysis was conducted to study the effect of different factors on drug release kinetics including environmental condition, material properties, and design parameters. The concentration profiles of counterions and drug species, the moving front of ion exchange, and three distinct regions inside a microsphere, namely unextracted region, ion-exchange region and drug diffusion region, were revealed by model prediction. The numerical results indicated that the rate of drug release increased with an increase in the initial drug concentration in the microspheres, the salt concentration in the external solution, or the valence of the counterions, whereas it decreased with increasing Langmuir isotherm constant. The mathematical and experimental procedures for determination of the equilibrium constant and the usefulness of the model were demonstrated using verapamil hydrochloride and sulfopropyl dextran microsphere system as an example. This work has provided a very useful mathematical tool for predicting kinetics and equilibrium of drug release and for optimizing the design of ion-exchange drug delivery systems. PMID:18192000

Abdekhodaie, Mohammad J; Wu, Xiao Yu

2008-04-01

393

GE Healthcare Data File 11-0025-76 AB Ion exchange chromatography  

E-print Network

GE Healthcare Data File 11-0025-76 AB Ion exchange chromatography Capto Q Figure 1. Capto Q-effective processing with smaller unit operations Media characteristics High throughput in downstream purification requires separation media that combine mechanical strength of the matrix with a pore structure that allows

Lebendiker, Mario

394

EVALUATION OF ION EXCHANGE SOFTENING ON THE LEACHING OF METALS FROM HOUSEHOLD PLUMBING SYSTEMS  

EPA Science Inventory

A 16 month pilot plant study was conducted to determine the effect of ion exchange softening on the leaching of metals from household plumbing materials. wo pipe loop pilot plant systems were assembled. ach system consisted of duplicate loops of lead pipe, copper pipe with 50:50 ...

395

The recovery of gold from ammoniacal thiosulfate solutions containing copper using ion exchange resin columns  

Microsoft Academic Search

The loading of gold and copper, both individually and simultaneously, from thiosulfate solutions onto ion exchange resin columns and the subsequent elution of these species have been investigated. In the presence of copper, effective loading with good selectivity for gold can be achieved at pH 11, which balances the stability of the solution and minimizes the formation of poisoning polythionates.

Hongguang Zhang; David B Dreisinger

2004-01-01

396

The development and characterization of ion exchange membranes for selected electrochemical power sources  

NASA Astrophysics Data System (ADS)

The work is reviewed on the development and characterization of ion exchange membranes in an effort to improve the efficiency of three flowing electrolyte batteries. The batteries are: (1) NASA's iron chromium redox battery; (2) Lockheed's zinc ferricyanide battery; and (3) Johnson Control's zinc bromine battery. These batteries were developed for solar photovoltaic, utility load leveling, and electric vehicle applications, respectively.

Arnold, C., Jr.; Assink, R. A.

397

Radiation deterioration of ion-exchange Nafion N117CS membranes  

NASA Astrophysics Data System (ADS)

The cation-exchange Nafion N117 membranes swelling in electrolyte solution were irradiated with ?-rays or electron beams at various doses up to 1500 kGy in the temperature range from room temperature to 343 K to obtain detailed information on the effect of ion-exchange on the radiation deterioration in mechanical properties and ion-exchange capacity. Considerable deterioration in mechanical properties was observed when the Nafion membranes swelling in electrolyte solution were irradiated. A reason is the promotion of degradation with oxygen molecules produced by the irradiation of electrolyte solution. The concentration of electrolyte solution influenced strongly the radiation deterioration in mechanical properties. Keeping the concentration of metal ions to be negligible is important when electrolyzed highly radioactive solution in the light of the durability of polyperfluorosulfonic acid (PFSA) membrane. A sort of cation in electrolyte solution negligibly influenced radiation deterioration in mechanical properties. A sort of anion in electrolyte solution had negligible effect on radiation deterioration in mechanical properties and ion-exchange capacity. The discrepancy in the radiation deterioration in mechanical properties of Nafion membranes swelling in NaCl solution was observed between the specimens irradiated with ?-rays and electron beams. This discrepancy can be explained from the low diffusivity of oxygen from bulk into the membrane.

Iwai, Yasunori; Hiroki, Akihiro; Tamada, Masao; Isobe, Kanetsugu; Yamanishi, Toshihiko

2010-01-01

398

ANNUAL REPORT. NEW METAL NIOBATE AND SILICOTITANATE ION EXCHANGERS: DEVELOPMENT AND CHARACTERIZATION  

EPA Science Inventory

This project focuses on the synthesis and characterization of silicotitanate- and niobate-based ion exchangers for Cs and Sr removal and their related condensed phases as potential ceramic waste forms, as well as on understanding the structural property relationship and thermodyn...

399

Development of Volume-Reduction System for Ion Exchange Resin Using Inductively Coupled Plasma  

Microsoft Academic Search

The spent ion exchange resin generated as radioactive waste in water purifying system at nuclear power stations or related facilities of nuclear power has been stored in the site, and its volume has been increasing year by year. We had developed a full-scale system of IC plasma volume-reduction system for the spent resin, and have performed basic performance test using

Morio Fujisawa; Genichi Katagiri

2002-01-01

400

Repeated Use of Ion-Exchange Resin Membranes in Calcareous Soils  

Microsoft Academic Search

This study compared the consistency of nutrient extraction among repeated cycles of ion-exchange resin membrane use. Two sandy calcareous soils and different equilibration temperatures were tested. No single nutrient retained consistent values from cycle to cycle in all treatments, although both soil source and temperature conferred some influence. It was concluded that the most conservative use of resin membranes is

S. K. Sherrod; J. Belnap; M. E. Miller

2003-01-01

401

ONE MGD ION EXCHANGE PLANT FOR REMOVAL OF NITRATE FROM WELL WATER  

EPA Science Inventory

A full scale 1 mgd demonstration plant, using ion exchange, for removal of nitrate from well water was built at McFarland, California. The plant has been performing satisfactorily in the semi-automatic mode since October 1983. Full automation of the plant was completed in June 19...

402

Magnetic Exchange Interaction between Rare-Earth and Mn Ions in Multiferroic Hexagonal Manganites  

E-print Network

Magnetic Exchange Interaction between Rare-Earth and Mn Ions in Multiferroic Hexagonal Manganites D 2008; published 9 December 2008) We report a study of magnetic dynamics in multiferroic hexagonal in solids. Recently, superexchange was found to me- diate magnetoelectric (ME) coupling in multiferroics

403

SUMMARY REPORT: CONTROL AND TREATMENT TECHNOLOGY FOR THE METAL FINISHING INDUSTRY: ION EXCHANGE  

EPA Science Inventory

This Technology Transfer ummary Report is one of a series of reports that summarizes a pollution control technology for the metal finishing industry. he 45-page report is intended to promote an understanding of the use of ion exchange in the metal finishing industry. The sections...

404

Development and testing of ion exchangers for treatment of liquid wastes at Oak Ridge National Laboratory  

SciTech Connect

This report addresses three areas of waste treatment: (1) treatment of newly generated low-level liquid waste and Melton Valley Storage Tank (MVST) supernate using inorganic ion exchangers; (2) treatment of processing streams at the Radiochemical Engineering Development Center (REDC); and (3) removal of radionuclides from organic solutions. Distribution of various radionuclides between simulated waste solutions and several sorbents was determined in batch tests. Inorganic ion exchangers were prepared in the form of microspheres by an intemal gelation process. Microspheres of hydrous titania, hydrous zirconia, hydrous titania containing embedded sodium cobalt hexacyanoferrate, and the corresponding phosphate forms of these materials were prepared. Several zeolites (PDZ-140, PDZ-300, EE-96, CBV-10A) and inorganic ion exchangers (hydrous titania, hydrous zirconia, polyantimanic acid, sodium cobalt hexacyanoferrate) were tested for the removal of cesium and strontium from the acidic simulated Cleanex raffinate generated at REDC. A resorcinol-based ion-exchange resin and three types of sodium titanate were tested for removal of cesium and strontium from the REDC caustic dissolver solution. Hydrous titania, hydrous zirconia, and their corresponding phosphates were tested for the removal of Eu{sup 3+} from various solutions of di-2-ethylbexyl phosphoric acid (HDEHP) in toluene or dodecane.

Collins, J.L.; Davidson, D.J.; Chase, C.W.; Egan, B.Z. [Oak Ridge National Lab., TN (United States); Ensor, D.D.; Bright, R.M.; Glasgow, D.C. [Tennessee Technological Univ., Cookeville, TN (United States)

1993-03-01

405

Development and testing of ion exchangers for treatment of liquid wastes at Oak Ridge National Laboratory  

SciTech Connect

This report addresses three areas of waste treatment: (1) treatment of newly generated low-level liquid waste and Melton Valley Storage Tank (MVST) supernate using inorganic ion exchangers; (2) treatment of processing streams at the Radiochemical Engineering Development Center (REDC); and (3) removal of radionuclides from organic solutions. Distribution of various radionuclides between simulated waste solutions and several sorbents was determined in batch tests. Inorganic ion exchangers were prepared in the form of microspheres by an intemal gelation process. Microspheres of hydrous titania, hydrous zirconia, hydrous titania containing embedded sodium cobalt hexacyanoferrate, and the corresponding phosphate forms of these materials were prepared. Several zeolites (PDZ-140, PDZ-300, EE-96, CBV-10A) and inorganic ion exchangers (hydrous titania, hydrous zirconia, polyantimanic acid, sodium cobalt hexacyanoferrate) were tested for the removal of cesium and strontium from the acidic simulated Cleanex raffinate generated at REDC. A resorcinol-based ion-exchange resin and three types of sodium titanate were tested for removal of cesium and strontium from the REDC caustic dissolver solution. Hydrous titania, hydrous zirconia, and their corresponding phosphates were tested for the removal of Eu[sup 3+] from various solutions of di-2-ethylbexyl phosphoric acid (HDEHP) in toluene or dodecane.

Collins, J.L.; Davidson, D.J.; Chase, C.W.; Egan, B.Z. (Oak Ridge National Lab., TN (United States)); Ensor, D.D.; Bright, R.M.; Glasgow, D.C. (Tennessee Technological Univ., Cookeville, TN (United States))

1993-03-01

406

Evaluation of Selective Ion Exchange Resins for Removal of Mercury from the H-Area Water Treatment Unit  

SciTech Connect

This study investigated the ability of seven ion exchange (IX) resins, some of which were mercury specific, to remove mercury in H-Area WTU waters from three sources (Reverse Osmosis (RO) Feed, RO Permeate from Train A, and a mercury ''hot spot'' extraction well HEX 18). Seven ion exchange resins, including ResinTech CG8 and Dowex 21K (the cation and anion exchange resins currently used at the H-Area WTU) were screened against five alternative ion exchange materials plus an experimental blank. Mercury decontamination factors (DFs), mercury breakthrough, and post-test contaminant concentrations of IX resins were determined for each IX material tested.

Serkiz, S.M.

2000-09-05

407

Separation and characterisation of beta2-microglobulin folding conformers by ion-exchange liquid chromatography and ion-exchange liquid chromatography-mass spectrometry.  

PubMed

In this work we present for the first time the use of ion-exchange liquid chromatography to separate the native form and a partially structured intermediate of the folding of the amyloidogenic protein beta2-microglobulin. Using a strong anion-exchange column that accounts for the differences in charge exposure of the two conformers, a LC-UV method is initially optimised in terms of mobile phase pH, composition and temperature. The preferred mobile phase conditions that afford useful information were found to be 35 mM ammonium formate, pH 7.4 at 25°C. The dynamic equilibrium of the two species is demonstrated upon increasing the concentration of acetonitrile in the protein sample. Then, the chromatographic method is transferred to MS detection and the respective charge state distributions of the separated conformers are identified. The LC-MS results demonstrate that one of the conformers is partially unfolded, compared with the native and more compact species. The correspondence with previous results obtained in free solution by capillary electrophoresis suggest that strong ion exchange LC-MS does not alter beta2-microglobulin conformation and maintains the dynamic equilibrium already observed between the native protein and its folding intermediate. PMID:23522119

Bertoletti, Laura; Regazzoni, Luca; Aldini, Giancarlo; Colombo, Raffaella; Abballe, Franco; Caccialanza, Gabriele; De Lorenzi, Ersilia

2013-04-10

408

Basis document for PFP plutonium nitrate ion exchange process in Room 228A  

SciTech Connect

The PFP facility currently has approximately 4300 liters of plutonium nitrate solution in storage. This material will be calcined by the Vertical Denigration Calciner (VDC) located in room 230C. However, part of the material needs to be purified to remove constituents that will interfere with the calcination process. An Ion Exchange process using Reillex{trademark} HPQ anion exchange resin was tested by the Plutonium Process Support Laboratories (PPSL) (I). The Ion exchange process is to be installed in glovebox HC-7 in room 228A/234-5Z. The plutonium separated from the interfering constituents will be in a concentrated condition ready to be calcined by the VDC in room 230C. The oxide product of the VDC will be placed into the 2736-Z vaults for long term storage.

Risenmay, H.R.

1997-04-23

409

Planar Waveguides Formed by Ag Na Ion Exchange in Nonlinear Optical Glasses: Diffusion and Optical Properties  

NASA Astrophysics Data System (ADS)

All-optical communication systems are the subject of intense research related to the integration of nonlinear optical materials. In sodiocalcic borophosphate glasses that contain niobium oxide and exhibit high nonlinear optical indices, planar waveguides have been formed by a Ag Na ion-exchange technique. WKB analysis has been used to characterize the diffusion profiles of silver ions exchanged in glass substrate samples chemically by an electron microprobe technique and optically by an M -line technique. These methods permit the Ag penetration depth and diffusion profile shape and index profiles to be determined. The results are analyzed and discussed in relation to Ca 2 concentration and exchange conditions in glasses. The Ag diffusion in these glasses can be almost entirely controlled for index-profile engineering.

Martin, Marc; Videau, Jean J.; Canioni, Lionel; Adamietz, Frédéric; Sarger, Laurent; Le Flem, Gilles

2000-01-01

410

Synthesis, characterization and ion-exchange properties of a new and novel ‘organic–inorganic’ hybrid cation-exchanger: Nylon6,6, Zr(IV) phosphate  

Microsoft Academic Search

Organic–inorganic hybrid materials enable the integration of useful organic and inorganic characteristics within a single molecular-scale composite. Unique ion-exchange properties of these types of materials have been observed, and many others can be envisioned for this promising class of materials. In this paper, we describe the ion-exchange and physico-chemical properties of one family of self-assembling organic–inorganic hybrid based on nylon-6,6,

Inamuddin; Shakeel Ahmad Khan; Weqar Ahmad Siddiqui; Asif Ali Khan

2007-01-01

411

Quantum ion-acoustic solitary waves: the effect of exchange correlation.  

PubMed

Quantum ion-acoustic solitary waves are studied by considering the effects of exchange and correlation for the electrons. Starting from one-dimensional quantum hydrodynamic equations, including the term of exchange correlation for electrons, we obtain a model in which two dimensionless parameters appear (in addition to the parameter measuring the quantum diffraction) measuring the exchange and the correlation. A new deformed Korteweg-de Vries equation is derived. The effect of exchange and correlation is reflected in the phase speed as well as in the nonlinear and dispersion terms. Its solution shows that the exchange-correlation effects modify the amplitude as well as the width of the weak solitary waves. In the arbitrary amplitude regime, and as may be expected, a pseudopotential analysis shows that the exchange-correlation effects may change the nature (compressive or rarefactive) of the quantum ion-acoustic solitary waves. Our results complement and give new insight into the previously published work on this problem. PMID:24229311

Ourabah, Kamel; Tribeche, Mouloud

2013-10-01

412

Ion Exchange Equilibrium and Kinetic Properties of Polyacrylate Films and Applications to Chemical Analysis and Environmental Decontamination  

NASA Technical Reports Server (NTRS)

One of the goals of the original proposal was to study how cross-linking affects the properties of an ion exchange material(IEM) developed at Lewis Research Center. However, prior to the start of this work, other workers at LERC investigated the effect of cross-linking on the properties of this material. Other than variation in the ion exchange capacity, the chemical characteristics were shown to be independent of the cross-linking agent, and the degree of cross-linking. New physical forms of the film were developed (film, supported film, various sizes of beads, and powder). All showed similar properties with respect to ion exchange equilibria but the kinetics of ion exchange depended on the surface area per unit mass; the powder form of the IEM exchanging much more rapidly than the other forms. The research performed under this grant was directed towards the application of the IEM to the analysis of metal ions at environmental concentrations.

Tanner, Stephen P.

1997-01-01

413

Degradation of salicylic acid by photo-assisted Fenton reaction using Fe ions on strongly acidic ion exchange resin as catalyst  

Microsoft Academic Search

The photo-assisted Fenton degradation of salicylic acid (SA) was studied by using strongly acidic ion exchange resin (SAIER) exchanged with Fe ions as catalyst in the presence of UV light (254nm) and H2O2. The X-ray photoelectron spectroscopy (XPS) results revealed that the Fe ions are indeed anchored by the sulfonate groups on the surface of the SAIER and are Fe3+.

Jiyun Feng; Xijun Hu; Po Lock Yue

2004-01-01

414

The Electrochemical Characterization of Ion Exchange Membranes in Different Electrolytic Environments: Investigation of Concentration and pH Effects  

Microsoft Academic Search

In this research, the effect of electrolyte concentration and environmental pH variations on electrochemical properties of two commercial heterogeneous ion exchange membranes was studied. Membrane structure investigation was carried out using the SEM method. Obtained images showed that the anion-exchange membrane possesses a rough surface while the cation-exchange one has mainly a smooth surface with effect on ions transportation ability.

S. M. Hosseini; S. S. Madaeni; A. R. Khodabakhshi

2012-01-01

415

The Electrochemical Characterization of Ion Exchange Membranes in Different Electrolytic Environments: Investigation of Concentration and pH Effects  

Microsoft Academic Search

In this research, the effect of electrolyte concentration and environmental pH variations on electrochemical properties of two commercial heterogeneous ion exchange membranes was studied. Membrane structure investigation was carried out using the SEM method. Obtained images showed that anion-exchange membrane possesses a rough surface while the cation-exchange one has mainly a smooth surface with effect on ions transportation ability. Membrane

S. M. Hosseini; S. S. Madaeni; A. R. Khodabakhshi

2011-01-01

416

Contact Activation of Blood Plasma and Factor XII by Ion-exchange Resins  

PubMed Central

Sepharose ion-exchange particles bearing strong Lewis acid/base functional groups (sulfopropyl, carboxymethyl, quarternary ammonium, dimethyl aminoethyl, and iminodiacetic acid) exhibiting high plasma protein adsorbent capacities are shown to be more efficient activators of blood factor XII in neat-buffer solution than either hydrophilic clean-glass particles or hydrophobic octyl sepharose particles ( FXII?surfaceactivatorFXIIa; a.k.a autoactivation, where FXII is the zymogen and FXIIa is a procoagulant protease). In sharp contrast to the clean-glass standard of comparison, ion-exchange activators are shown to be inefficient activators of blood plasma coagulation. These contrasting activation properties are proposed to be due to the moderating effect of plasma-protein adsorption on plasma coagulation. Efficient adsorption of blood plasma proteins unrelated to the coagulation cascade impedes FXII contacts with ion-exchange particles immersed in plasma, reducing autoactivation, and causing sluggish plasma coagulation. By contrast, plasma proteins do not adsorb to hydrophilic clean glass and efficient autoactivation leads directly to efficient activation of plasma coagulation. It is also shown that competitive-protein adsorption can displace FXIIa adsorbed to the surface of ion-exchange resins. As a consequence of highly-efficient autoactivation and FXIIa displacement by plasma proteins, ion-exchange particles are slightly more efficient activators of plasma coagulation than hydrophobic octyl sepharose particles that do not bear strong Lewis acid/base surface functionalities but to which plasma proteins adsorb efficiently. Plasma proteins thus play a dual role in moderating contact activation of the plasma coagulation cascade. The principal role is impeding FXII contact with activating surfaces but this same effect can displace FXIIa from an activating surface into solution where the protease can potentiate subsequent steps of the plasma coagulation cascade. PMID:21982294

Yeh, Chyi-Huey Josh; Dimachkie, Ziad O.; Golas, Avantika; Cheng, Alice; Parhi, Purnendu; Vogler, Erwin A.

2011-01-01

417

Chaotic behavior of ion exchange phenomena in polymer gel electrolytes through irradiated polymeric membrane  

E-print Network

A desktop experiment has been done to show the nonlinearity in the I-V characteristics of an ion conducting electrochemical micro-system. Its chaotic dynamics is being reported for the first time which has been captured by an electronic circuit. Polyvinylidene fluoride-co-hexafluoropropene (PVdF-HFP) gel electrolyte comprising of a combination of plasticizers (ethylene carbonate and propylene carbonate) and salts have been prepared to study the exchange of ions through porous poly ethylene terephthalate (PET) membranes. The nonlinearity of this system is due to the ion exchange of the polymer gel electrolytes (PGEs) through a porous membrane. The different regimes of spiking and non-spiking chaotic motions are being presented. The possible applications are highlighted.

Sangeeta Rawat; Barnamala Saha; Awadhesh Prasad; Amita Chandra

2012-04-18

418

Electrosorptive desalination by carbon nanotubes and nanofibres electrodes and ion-exchange membranes.  

PubMed

A novel membrane capacitive deionization (MCDI) device, integrating both the advantages of carbon nanotubes and carbon nanofibers (CNTs-CNFs) composite film and ion-exchange membrane, was proposed with high removal efficiency, low energy consumption and low cost. The CNTs-CNFs film was synthesized by low pressure and low temperature thermal chemical vapor deposition. Several experiments were conducted to compare desalination performance of MCDI with capacitive deionization (CDI), showing that salt removal of the MCDI system was 49.2% higher than that of the CDI system. The electrosorption isotherms of MCDI and CDI show both of them follow Langmuir adsorption, indicating no change in adsorption behavior when ion-exchange membranes are introduced into CDI system. The better desalination performance of MCDI than that of CDI is due to the minimized ion desorption during electrosorption. PMID:18929385

Li, Haibo; Gao, Yang; Pan, Likun; Zhang, Yanping; Chen, Yiwei; Sun, Zhuo

2008-12-01

419

Competitive migration behaviors of multiple ions and their impacts on ion-exchange resin packed microbial desalination cell.  

PubMed

Mixed ion-exchange resins packed microbial desalination cell (R-MDC) could stabilize the internal resistance, however, the impacts of multiple ions on R-MDC performance was unclear. This study investigated the desalination performance, multiple ions migration behaviors and their impacts on R-MDCs fed with salt solution containing multiple anions and cations. Results showed that R-MDC removed multiple anions better than multiple cations with desalination efficiency of 99% (effluent conductivity <0.05 ms/cm) at hydraulic retention time of 50 h. Competitive migration order was SO4(2-)>NO3(-)>Cl(-) for anions and Ca(2+)?Mg(2+)>NH4(+)>Na(+) for cations, jointly affected by both their molar conductivity and exchange selectivity on resins. After long-term operation, the existence of higher concentration Ca(2+) and Mg(2+) caused the electric conductivity of mixed resins decrease and scaling on the surface of cation-exchange membrane adjoined with cathode chamber, suggesting that R-MDC would be more suitable for desalination of water with lower hardness. PMID:23982060

Zuo, Kuichang; Yuan, Lulu; Wei, Jincheng; Liang, Peng; Huang, Xia

2013-10-01

420

Biodiesel production using anionic ion-exchange resin as heterogeneous catalyst.  

PubMed

The transesterification reactions of triolein with ethanol using various ion-exchange resin catalysts were conducted to produce ethyl oleate as a biodiesel. The anion-exchange resins exhibited much higher catalytic activities than the cation-exchange resin. The anion-exchange resin with a lower cross-linking density and a smaller particle size gave a high reaction rate as well as a high conversion. By combining the three-step regeneration method, the resin could be repeatedly used for the batch transesterification without any loss in the catalytic activity. A continuous transesterification reaction was carried out using an expanded bed reactor packed with the most active resin. The reactor system permitted the continuous production of ethyl oleate with a high conversion. PMID:16455240

Shibasaki-Kitakawa, Naomi; Honda, Hiroki; Kuribayashi, Homare; Toda, Takuji; Fukumura, Takuya; Yonemoto, Toshikuni

2007-01-01

421

Forward and reverse ion-exchange kinetics for some alkali and alkaline earth metal ions on amorphous zirconium(IV) aluminophosphate  

SciTech Connect

The Nernst-Planck equations are applied to study the ion-exchange kinetics on the surface of zirconium(IV) aluminophosphate for Li{sup +}/H{sup +}, Na{sup +}/H{sup +}, K{sup +}/H{sup +}, Mg{sup 2+}/H{sup +}, Ca{sup 2+}/H{sup +}, and Sr{sup 2+}/H{sup +} exchanges in the forward and reverse directions under the conditions favoring particle diffusion. On the basis of these studies, various physical parameters such as the self-diffusion coefficient (D{sub 0}), the energy of activation (E{sub a}), and the entropy of activation ({Delta}S*) have been determined and a correlation has been made of these parameters with the ion-exchange characteristics of the material. The study gives an insight into the ion-exchange processes going on in the exchanger phase and its potential use in metal ion separations.

Varshney, K.G.; Pandith, A.H.

1999-10-26

422

Ion exchange membranes as electrolyte to improve high temperature capacity retention of LiMn2O4 cathode lithium-ion batteries.  

PubMed

A LiMn(2)O(4) cathode lithium-ion battery using lithiated ion exchange membranes swollen with organic non-aqueous solvent as the electrolyte to overcome capacity fading at high temperature is first demonstrated, and shows very good capacity retention compared with conventional lithium-ion batteries using liquid electrolyte. PMID:22903057

Liu, Yanbo; Tan, Lei; Li, Lei

2012-10-11

423

Overloading ion-exchange membranes as a purification step for monoclonal antibodies  

PubMed Central

The present study examined the overloading of ion-exchange membrane adsorbers, a form of frontal chromatography, as the final purification step in the production of mAbs (monoclonal antibodies) produced from CHO (Chinese-hamster ovary) cells. Preferential binding of impurities over antibody product was exploited using commercially available cation- and anion-exchange membranes. Three different antibody feedstreams previously purified over Protein A and ion-exchange column chromatography were tested. Feedstream conductivity and pH were adjusted to induce product and impurity adsorption. Membranes were then overloaded in a normal flow mode, resulting in retention of impurities and breakthrough of purified antibody. Although some amount of the product also binds to the membranes (usually ?30 g mAb/l membrane), yields of ?99% were achieved by marginalizing the losses, typically by loading more than 3 kg mAb/l membrane. Analyses of the purified pools show consistent removal of impurities despite strong mAb–ligand interactions and high membrane loadings. The clearance of host cell proteins was affected by pH and conductivity, but was unaffected by flow rate, membrane properties or scale. The importance of the present study lies in our demonstration of an alternative use of ion-exchange membranes for fast, effective and high yielding purification of mAbs. PMID:20497123

Brown, Arick; Bill, Jerome; Tully, Timothy; Radhamohan, Asha; Dowd, Chris

2010-01-01

424

Preparation of Ion Exchange Films for Solid-Phase Spectrophotometry and Solid-Phase Fluorometry  

NASA Technical Reports Server (NTRS)

Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this report we present a method for making ion exchange polymer films, which considerably simplify the solid-phase spectroscopic techniques. The polymer consists of formaldehyde-crosslinked polyvinyl alcohol with polyacrylic acid entrapped therein. The films are a carboxylate weak cation exchanger in the calcium form. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.

Hill, Carol M.; Street, Kenneth W.; Tanner, Stephen P.; Philipp, Warren H.

2000-01-01

425

Utilization of ion exchanger and spectrophotometry for assaying amoxycillin and flucloxacillin in dosage form.  

PubMed

A simple, rapid, accurate sensitive spectrophotometry procedure for the determination of amoxycillin (Amox) and flucloxacillin (Fluclox) in bulk samples and in dosage forms are developed. The procedure involves the use of sudan III as chromogenic reagent to produce a violet colored ion-pair with an absorption maximum at 566nm. The ion-pair complexes obey Beer's law and are suitable for the quantitative determination of 0.2-22 and 0.4-25microg/ml of Amox, and Fluclox, respectively. The optimization of different experimental conditions is described in which Amox react after 3min at 25+/-1 degrees C, whereas Fluclox take 10min at 60+/-1 degrees C. Tin(IV) antimonite ion exchanger was utilized to separate a mixture of Amox and Fluclox trihydrate. A column chromatographic technique was applied to separation the antibiotics mixture. Column of 0.3mm diameter and bed height of 3cm of the exchanger was used and the frontal elution technique was utilized. The separation factor for Fluclox and Amox was found to be 2.76. Tin(IV) antimonite ion exchanger exhibit promising feature that can be utilized as stationary phase in either HPLC or HPTLC techniques. The procedure described was applied successfully to determine Amox and Fluclox. The obtained results were compared the official methods. The proposed procedure was successfully applied to determine Amox and Fluclox in their pharmaceutical formulations. PMID:17374465

Aly, Hisham M; Amin, Alaa S

2007-06-29

426

Recovery of steroidal glucosiduronic acids from organic solvents containing anionic liquid ion-exchangers.  

PubMed

Solutions of anionic liquid ion-exchangers in organic solvents are potentially useful for extracting steroidal glucosiduronic acids from biological fluids and for purifying mixtures of these acids by chromatography. If a glucosiduronic acid is to be isolated in pure form after either of these procedures, it is necessary to separate it from the ion-exchanger. Separation from an organic solution of tetraheptylammonium chloride may be accomplished by extraction with water under the following conditions, which promote transfer of a glucosiduronate to the aqueous phase: (1) an appropriate solvent (diluent) as the organic phase, (2) the presence in the two-phase mixture of an anion such as myristate or dodecyl sulphate to combine with the tetraheptylammonium ion, and (3) an increase of the pH of the aqueous phase in association with the presence of myristate or dodecyl sulphate. The foregoing factors apply also to removal of glucosiduronates from organic solutions of ion exchangers that are hydrochlorides of tertiary, secondary, or primary amines. Since these amines exert progressively less solubilizing effect for glucosiduronates as the pH of the aqueous phase is increased, the conjugates can be released from the organic phase by adjusting the pH to 10 and omitting the myristate or dodecyl sulphate. PMID:5075265

Mattox, V R; Litwiller, R D; Goodrich, J E

1972-02-01

427

Removal of catalyst in polybutene production by treatment with ion exchange resin  

SciTech Connect

The development of process technology for removal of AlCl/sub 3/ from the reaction mass obtained in the polymerization of butenes by treatment with ion exchange resins is reported. This work also investigated certain reactions that take place in this treatment. It is proposed that the polymerized product should be treated with KU-2-8 cation exchange resin in the H form. The study demonstrates that by the use of resin treatment of the polymerized product that has been prehomogenized with alcohols, it becomes possible to produce low molecular weight polybutenes in a low waste process.

Vlasov, A.V.; Prokof'ev, K.V.; Sangalov, Yu.A.; Kotov, S.V.

1988-09-01

428

Evidence of electron saddle swap oscillations in angular differential ion-atom charge exchange cross sections  

NASA Astrophysics Data System (ADS)

State selective charge exchange processes in 1-10 keV/amu Ne8+ +Na(3s) collisions were measured by means of the magneto-optical trap recoil-ion momentum spectroscopy technique and compared to classical trajectory Monte Carlo calculations. We find that for electron capture to n-levels ? 10, the transverse momentum distributions exhibit an oscillatory structure which is very sensitive to the impact energy. Our theoretical analysis suggests that this feature is a direct consequence of the number of swaps the electron undergoes across the potential energy saddle during the charge exchange process.

Otranto, S.; Blank, I.; Olson, R. E.; Hoekstra, R.

2012-09-01

429

Design of high efficiency fibers for ion exchange and heavy metal removal  

NASA Astrophysics Data System (ADS)

Ion exchange materials coated on glass fiber substrates have a number of advantages over the conventional ion exchange beads. These include simplification of the overall synthesis including faster more efficient functionalization and elimination of toxic solvents. Other benefits include the ability to be fabricated in the form of felts, papers, or fabrics, improving media contact efficiency and enhancing both the rates of reaction and regeneration. In addition, physical and mechanical requirements of strength and dimensional stability are achieved by use of glass fiber substrates. Investigations were focused on design of: (1) polymeric cationic exchange fibers and their application for lead and mercury removal, (2) polymeric anionic exchange fibers and their application for arsenate removal, (3) enhancement of anionic fiber selectivity for monovalent ions over divalent ions through bulkier triaklylamine functional groups, and (4) polymeric mercaptyl fibers for the application of arsenite removal. The design and characterization of a cationic exchange fiber is described. Dynamic mode (breakthrough) experiments for calcium, lead, and mercury ion solutions are also presented. The second system consists of the preparation and characterization of anionic exchange fibers with equilibrium adsorption isotherms and dynamic mode kinetic experiments for arsenate removal. Modification of the resin with bulkier functional groups (trimethylamine, triethylamine, tripropylamine, tributylanmine), thereby effecting a change in the selectivity from divalent species to monovalent species, is considered in the separation of nitrates from sulfates. The ability of a thiol group to bind to the highly toxic arsenite ion (as is done in proteins and enzymes) provided the model used to chemically modify and characterize a polyvinyl alcohol mercaptyl fibrous system, coated on a fiberglass substrate, for the purpose of arsenite (As3+) removal from water. Physical/chemical aspects of naturally occurring thiols and disulfides was used to draw parallels to observations found with the polyvinyl alcohol mercaptyl system and its reactivity towards arsenite. The ability of these systems to chelate arsenite was presented through equilibrium adsorption isotherms. All fibrous systems were characterized through a variety of techniques such as scanning electron microscopy, diffuse reflectance infrared spectroscopy, elemental analysis, analytical analysis, and thermal analysis of the copolymer.

Dominguez, Lourdes

430

Photocatalytic reduction of nitrate using titanium dioxide for regeneration of ion exchange brine.  

PubMed

Nitrate is often removed from groundwater by ion exchange (IX) before its use as drinking water. Accumulation of nitrate in IX brine reduces the efficiency of IX regeneration and the useful life of the regeneration brine. For the first time, we present a strategy to photocatalytically reduce nitrate in IX brine, thereby extending the use of the brine. Titanium dioxide (Evonik P90), acting as photocatalyst, reduced nitrate effectively in both synthetic brines and sulfate-removed IX brine when formic acid (FA) was used as the hole scavenger (i.e., electron donor) and the initial FA to nitrate molar ratio (IFNR) was 5.6. Increasing the NaCl level in the synthetic brine slowed the nitrate reduction rate without affecting by-product selectivity of ammonium and gaseous N species (e.g., N(2), N(2)O). In a non-modified IX brine, nitrate removal was greatly inhibited owing to the presence of sulfate, which competed with nitrate for active surface sites on P90 and induced aggregation of P90 nanoparticles. After removing sulfate through barium sulfate precipitation, nitrate was effectively reduced; approximately 3.6 × 10(24) photons were required to reduce each mole of nitrate to 83% N Gases and 17% NH(4)(+). To make optimum use of FA and control the residual FA level in treated brine, the IFNR was varied. High IFNRs (e.g., 4, 5.6) were found to be more efficient for nitrate reduction but left higher residual FA in brine. IX column tests were performed to investigate the impact of residual FA for brine reuse. The residual FA in the brine did not significantly affect the nitrate removal capacity of IX resins, and formate contamination of treated water could be eliminated by rinsing with one bed volume of fresh brine. PMID:23276425

Yang, Ting; Doudrick, Kyle; Westerhoff, Paul

2013-03-01

431

Charge-exchange recombination spectroscopy of the plasma ion temperature at the T-10 tokamak  

SciTech Connect

Charge-exchange recombination spectroscopy (CXRS) based on a diagnostic neutral beam has been developed at the T-10 tokamak. The diagnostics allows one to measure the ion temperature profile in the cross section of the plasma column. In T-10 experiments, the measurement technique was adjusted and the elements of the CXRS diagnostics for ITER were tested. The used spectroscopic equipment makes it possible to reliably determine the ion temperature from the Doppler broadening of impurity lines (helium, carbon), as well as of the spectral lines of the working gas. The profiles of the plasma ion temperature in deuterium and helium discharges were measured at different plasma currents and densities, including with the use of active Doppler measurements of lines of different elements. The validity and reliability of ion temperature measurements performed by means of the developed CXRS diagnostics are analyzed.

Krupin, V. A., E-mail: vkrupin@nfi.kiae.ru [National Research Centre Kurchatov Institute (Russian Federation); Tugarinov, S. N. [Project Center ITER (Russian Federation)] [Project Center ITER (Russian Federation); Barsukov, A. G.; Dnestrovskij, A. Yu.; Klyuchnikov, L. A.; Korobov, K. V.; Krasnyanskii, S. A. [National Research Centre Kurchatov Institute (Russian Federation)] [National Research Centre Kurchatov Institute (Russian Federation); Naumenko, N. N. [National Academy of Sciences of Belarus, Stepanov Institute of Physics (Belarus)] [National Academy of Sciences of Belarus, Stepanov Institute of Physics (Belarus); Nemets, A. R.; Sushkov, A. V.; Tilinin, G. N. [National Research Centre Kurchatov Institute (Russian Federation)] [National Research Centre Kurchatov Institute (Russian Federation)

2013-08-15

432

A mechanism for enhancing ionic accessibility into selective ion exchange resins  

SciTech Connect

A bifunctional monophosphonic/sulfonic acid ion exchange resin with high capacity has been synthesized. Metal ion studies have been carried out with europium, americium, and ferric nitrate in solutions of varying acidity, with and without sodium nitrate added. The bifunctional resin complexes far higher levels of Eu(III) from 0.5 and 1 N nitric acid than the monofunctional phosphonic acid resin. It is postulated that the sulfonic acid ligand provides an access mechanism for the metal ions into the polymer matrix by hydrating the matrix and preventing its collapse in high ionic strength solutions thus allowing for rapid ionic complexation by the selective phosphonic acid ligands. The bifunctional monophosphonic/sulfonic acid resin has both ligands bound to a polystyrene support. It complexes higher levels of metal ions than a comparable resin differing only by having the monophosphonic acid ligand directly bound to the C-C backbone. Results are compared to a diphosphonic/sulfonic acid resin.

Alexandratos, S.D.; Shelley, C.A. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Horwitz, E.P.; Chiarizia, R. [Argonne National Lab., IL (United States). Chemistry Div.

1998-07-01

433

Inference of the ring current ion composition by means of charge exchange decay  

NASA Technical Reports Server (NTRS)

The analysis of the measured ion fluxes during the several day storm recovery period and the assumption that beside hydrogen other ions were present and that the decays were exponential in nature, it was possible to establish three separate lifetimes for the ions. These fitted decay lifetimes are in excellent agreement with the expected charge exchange decay lifetimes for H(+), O(+), and He(+) in the energy and L-value range of the data. This inference technique, thus, establishes the presence of measurable and appreciable quantities of oxygen and helium ions as well as protons in the storm-time ring current. Indications that He(+) may also be present under these same conditions were found.

Smith, P. H.; Bewtra, N. K.; Hoffman, R. A.

1978-01-01

434

Modelling Mixed Bed Ion Exchange Kinetics for Removal of Trace Levels of Divalent Cations in Ultrapure Water  

SciTech Connect

Ion exchanger resin fluid film mass transfer coefficients and the ionic diffusivities from which they are derived are often measured by use of ion exchange resin columns. Such tests, usually run dynamically using short resin beds, are often performed using relatively high (ppm) concentrations of ions to accurately measure output concentrations as a function of flow rate. The testing described herein was performed to determine fluid film ionic diffusivities for cationic concentrations typical of ultrapure water ({le}ppb levels) containing ppm levels of ammonia. Effective ionic diffusivities at these low ionic concentrations and high pHs were needed to complete a computer model (SIMIX) to be used in ion exchange simulations. SIMIX is a generalized multicomponent ion exchange model designed to simulate the removal of divalent cations from ultrapure water.

B. Widman

2003-01-01

435

Disease-associated changes in the expression of ion channels, ion receptors, ion exchangers and Ca{sup 2+}-handling proteins in heart hypertrophy  

SciTech Connect

The molecular pathology of cardiac hypertrophy is multifactorial with transcript regulation of ion channels, ion exchangers and Ca{sup 2+}-handling proteins being speculative. We therefore investigated disease-associated changes in gene expression of various ion channels and their receptors as well as ion exchangers, cytoskeletal proteins and Ca{sup 2+}-handling proteins in normotensive and spontaneously hypertensive (SHR) rats. We also compared experimental findings with results from hypertrophic human hearts, previously published (Borlak, J., and Thum, T., 2003. Hallmarks of ion channel gene expression in end-stage heart failure. FASEB J. 17, 1592-1608). We observed significant (P < 0.05) induction in transcript level of ATP-driven ion exchangers (Atp1A1, NCX-1, SERCA2a), ion channels (L-type Ca{sup 2+}-channel, K{sub ir}3.4, Na{sub v}1.5) and RyR-2 in hypertrophic hearts, while gene expression was repressed in diseased human hearts. Further, the genes coding for calreticulin and calmodulin, PMCA 1 and 4 as well as {alpha}-skeletal actin were significantly (P < 0.05) changed in hypertrophic human heart, but were unchanged in hypertrophic left ventricles of the rat heart. Notably, transcript level of {alpha}- and {beta}-MHC, calsequestrin, K{sub ir}6.1 (in the right ventricle only), phospholamban as well as troponin T were repressed in both diseased human and rat hearts. Our study enabled an identification of disease-associated candidate genes. Their regulation is likely to be the result of an imbalance between pressure load/stretch force and vascular tonus and the observed changes may provide a rational for the rhythm disturbances observed in patients with cardiac hypertrophy.

Zwadlo, Carolin [Fraunhofer Institute of Toxicology and Experimental Medicine, Center for Drug Research and Medical Biotechnology, Hannover (Germany); Borlak, Juergen [Fraunhofer Institute of Toxicology and Experimental Medicine, Center for Drug Research and Medical Biotechnology, Hannover (Germany)]. E-mail: borlak@item.fraunhofer.de

2005-09-15

436

Irradiation induced dissolution of Cu and growth of Ag nanoclusters in Cu\\/Ag ion-exchanged soda-lime glass  

Microsoft Academic Search

Complex metal nanoclusters of Cu\\/Ag are formed in a soda-lime glass matrix by sequential copper and silver ion-exchange followed by ion irradiation. Optical absorption measurements showed signature of copper clusters alone in the Cu\\/Ag ion-exchanged sample. Irradiation of the ion-exchanged sample with He+ ions of energy 100 keV of different fluences resulted in the growth of the silver clusters with,

D. Manikandan; S. Mohan; P. Magudapathy; K. G. M Nair

2002-01-01

437

Transmittance properties and TEM observation of metal doped glass by field-assisted ion exchange  

NASA Astrophysics Data System (ADS)

Metal (silver or copper) ions were doped into borosilicate glass using an electric field- assisted ion exchange method. The optical transmittance of the metal doped glass was measured to determine why the doped glass exhibited an excellent laser micro-machinability. The doped metal ions were found to have enhanced the optical absorption of the glass, especially in the ultraviolet range. This in turn facilitated the efficient absorption of incident laser irradiation, and hence improved laser machinability of the glass. The metal doped glass also exhibited some absorption in the visible range, leading to a slight yellow-brown coloration. Transmission electron microscope (TEM) observations indicated that the metal ions had penetrated the glass and therein formed nanometer-sized (~6 nm) fine particles. In an attempt to control the optical characteristics in the ultraviolet-visible range, metal doped glass was heat-treated following the ion exchange doping step. In the case of silver-doped glass with heat treatment at 723 K, silver nanoparticles aggregated locally yielding an inhomogeneous structure. The heat-treated samples had a high optical absorption in the ultraviolet range.

Matsusaka, Souta; Nomura, Taketsugu; Hidai, Hirofumi; Chiba, Akira; Morita, Noboru

2014-08-01

438

A photodiode-based neutral particle bolometer for characterizing charge-exchanged fast-ion behavior  

SciTech Connect

A neutral particle bolometer (NPB) has been designed and implemented on Tri Alpha Energy's C-2 device in order to spatially and temporally resolve the charge-exchange losses of fast-ion populations originating from neutral beam injection into field-reversed configuration plasmas. This instrument employs a silicon photodiode as the detection device with an integrated tungsten filter coating to reduce sensitivity to light radiation. Here we discuss the technical aspects and calibration of the NPB, and report typical NPB measurement results of wall recycling effects on fast-ion losses.

Clary, R.; Smirnov, A.; Dettrick, S.; Knapp, K.; Korepanov, S.; Ruskov, E. [Tri Alpha Energy, Inc., Rancho Santa Margarita, California 92688 (United States); Heidbrink, W. W.; Zhu, Y. [University of California-Irvine, Irvine, California 92697 (United States)

2012-10-15

439

Establishing ion ratio thresholds based on absolute peak area for absolute protein quantification using protein cleavage isotope dilution mass spectrometry.  

PubMed

Quantitative mass spectrometry has become central to the field of proteomics and metabolomics. Selected reaction monitoring is a widely used method for the absolute quantification of proteins and metabolites. This method renders high specificity using several product ions measured simultaneously. With growing interest in quantification of molecular species in complex biological samples, confident identification and quantitation has been of particular concern. A method to confirm purity or contamination of product ion spectra has become necessary for achieving accurate and precise quantification. Ion abundance ratio assessments were introduced to alleviate some of these issues. Ion abundance ratios are based on the consistent relative abundance (RA) of specific product ions with respect to the total abundance of all product ions. To date, no standardized method of implementing ion abundance ratios has been established. Thresholds by which product ion contamination is confirmed vary widely and are often arbitrary. This study sought to establish criteria by which the relative abundance of product ions can be evaluated in an absolute quantification experiment. These findings suggest that evaluation of the absolute ion abundance for any given transition is necessary in order to effectively implement RA thresholds. Overall, the variation of the RA value was observed to be relatively constant beyond an absolute threshold ion abundance. Finally, these RA values were observed to fluctuate significantly over a 3 year period, suggesting that these values should be assessed as close as possible to the time at which data is collected for quantification. PMID:25154770

Loziuk, Philip L; Sederoff, Ronald R; Chiang, Vincent L; Muddiman, David C

2014-09-29

440

Indentation crack shapes and their evolution during subcritical crack growth in ion-exchanged glasses  

SciTech Connect

The influence of surface residual stress on indentation crack shape and its evolution during subcritical crack growth was studied in ion-exchanged soda-lime and sodium alumino-silicate glasses. Crack shapes were determined optically from crack-arrest markings which were generated on the fracture surfaces during crack extension. The shapes, both after indentation and subsequent subcritical growth, were found to be very different from the semielliptical shapes observed in stress-free glasses. It was observed that high residual surface compression pinned the cracks near the failure origin (indentation site) and the growth occurred totally below the surface. The influence of the extent and the magnitude of the surface compression on crack-shape evolution was examined. It was found that the depth of the crack in ion-exchanged glasses was larger as compared to stress-free glasses. Furthermore, the depth of the crack increased with an increase in the compression layer thickness.

Dwivedi, P.J.; Green, D.J. [Pennsylvania State Univ., University Park, PA (United States)

1996-12-31

441

Protein losses in ion-exchange and hydrophobic interaction high-performance liquid chromatography  

SciTech Connect

Protein losses in ion-exchange and hydrophobic interaction HPLC were examined. The supports were allnon-porous, packed in columns of identical dimensions. Two ion-exchange chromatography (IEC), anion and cation, as well as a hydrophobic interaction chromatography (HIC) columns were tested. Proteins included cytochrome c, bovine serum albumin (BSA), immunoglobulin G and fibrinogen. Temperature effects on HIC supports were studied for cytochrome c and BSA. Both retention times and recoveries of the proteins were measured. The influence of column residence time on the recovery of proteins were also investigated. We found a linear relationship between the amount of protein recovered and the log of the molecular mass. Retention times also generally increased with temperature for both HIC and IEC. Other trends in retention behavior and recoveries are discussed.

Goheen, Steven C.; Gibbins, Betty M.

2000-01-01

442

The characteristic assessment of spent ion exchange resin from PUSPATI TRIGA REACTOR (RTP) for immobilization process  

NASA Astrophysics Data System (ADS)

In this paper, spent ion exchange resin generated from PUSPATI TRIGA reactor (RTP) in Malaysian Nuclear Agency were characterized based on the water content, radionuclide content and radionuclide leachability. The result revealed that the water content in the spent resin is 48%. Gamma spectrometry analysis indicated the presence of 134Cs, 137Cs, 152Eu, 54Mn, 58Co, 60Co and 65Zn. The leachability test shows a small concentrations (<1 Bq/l) of 152Eu and 134Cs were leached out from the spent resin while 60Co activity concentrations slightly exceeded the limit generally used for industrial wastewater i.e. 1 Bq/l. Characterization of spent ion exchange resin sampled from RTP show that this characterization is important as a basis to immobilize this radioactive waste using geopolymer technology.

Wahida, Nurul; Yasir, Muhamad Samudi; Majid, Amran Ab; Wahab, Mohd Abd; Marzukee, Nik; Paulus, Wilfred; Phillip, Esther; Thanaletchumy, Irwan, M. N.

2014-09-01

443

Charge-exchange erosion studies of accelerator grids in ion thrusters  

NASA Technical Reports Server (NTRS)

A particle simulation model is developed to study the charge-exchange grid erosion in ion thrusters for both ground-based and space-based operations. Because the neutral gas downstream from the accelerator grid is different for space and ground operation conditions, the charge-exchange erosion processes are also different. Based on an assumption of now electric potential hill downstream from the ion thruster, the calculations show that the accelerator grid erosion rate for space-based operating conditions should be significantly less than experimentally observed erosion rates from the ground-based tests conducted at NASA Lewis Research Center (LeRC) and NASA Jet Propulsion Laboratory (JPL). To resolve this erosion issue completely, we believe that it is necessary to accurately measure the entire electric potential field downstream from the thruster.

Peng, Xiaohang; Ruyten, Wilhelmus M.; Keefer, Dennis

1993-01-01

444

Modulation of terrestrial ion escape flux composition /by low-altitude acceleration and charge exchange chemistry/  

NASA Technical Reports Server (NTRS)

Motivated by recent observations of highly variable hot plasma composition in the magnetosphere, control of the ionospheric escape flux composition by low-altitude particle dynamics and ion chemistry has been investigated for an e(-), H(+), O(+) ionosphere. It is found that the fraction of the steady state escape flux which is O(+) can be controlled very sensitively by the occurrence of parallel or transverse ion acceleration at altitudes below the altitude where the neutral oxygen density falls rapidly below the neutral hydrogen density and the ionospheric source of O(+) tends to be rapidly converted by charge exchange to H(+). The acceleration is required both to overcome the gravitational confinement of O(+) and to violate charge exchange equilibrium so that the neutral hydrogen atmosphere appears 'optically' thin to escaping O(+). Constraints are placed on the acceleration processes, and it is shown that O(+) escape is facilitated by observed ionospheric responses to magnetic activity.

Moore, T. E.

1980-01-01

445

Ca2+ Regulation of Ion Transport in the Na+/Ca2+ Exchanger*  

PubMed Central

The binding of Ca2+ to two adjacent Ca2+-binding domains, CBD1 and CBD2, regulates ion transport in the Na+/Ca2+ exchanger. As sensors for intracellular Ca2+, the CBDs form electrostatic switches that induce the conformational changes required to initiate and sustain Na+/Ca2+ exchange. Depending on the presence of a few key residues in the Ca2+-binding sites, zero to four Ca2+ ions can bind with affinities between 0.1 to 20 ?m. Importantly, variability in CBD2 as a consequence of alternative splicing modulates not only the number and affinities of the Ca2+-binding sites in CBD2 but also the Ca2+ affinities in CBD1. PMID:22822067

Hilge, Mark

2012-01-01

446

High-speed ion-exchange separations prior to neptunium, plutonium, and impurity assays  

Microsoft Academic Search

Separation of actinides and\\/or impurities prior to assay is required when sample matrix components interfere with the assay method. Separations frequently must be performed in glove boxes or shielded and analytical cells due to high levels of alpha\\/beta-gamma radioactivity. Conventional ion-exchange separations are typically more effective and quantitative than solvent extraction, but are prohibitively slow for routine application. At the

S. L. Maxwell; M. H. Forrest

1986-01-01

447

Storage and Aging Effects on Spherical Resorcinol-Formaldehyde Resin Ion Exchange Performance  

SciTech Connect

Bechtel National, Inc. (BNI) is evaluating the alternate Cs ion exchanger, spherical resorcinol-formaldehyde (RF), for use in the River Protection Project-Waste Treatment Plant (RPP-WTP).( ) Previous test activities with spherical RF indicate that it has adequate capacity, selectivity, and kinetics to perform in the plant according to the flowsheet needs. It appears to have better elution and hydraulic properties than the existing alternatives: ground-gel RF and SuperLig® 644 (SL 644).( ) To date, the spherical RF performance testing has been conducted on freshly manufactured resin (within ~2 months of manufacture). The ion exchange resins will be manufactured and shipped to the WTP up to 1 year before being used in the plant. Changes in the resin properties during storage could reduce the capacity of the resin to remove Cs from low-activity waste solutions. Active sites on organic SL-644 resin have been shown to degrade during storage (Arm et al. 2004). Additional testing was needed to study the effects of storage conditions and aging on spherical RF ion exchange performance. Variables that could have a significant impact on ion exchange resins during storage include storage temperature, medium, and time. Battelle—Pacific Northwest Division (PNWD) was contracted to test the effects of various storage conditions on spherical RF resin. Data obtained from the testing will be used by the WTP operations to provide direction for suitable storage conditions and manage the spherical RF resin stock. Storage test conditions included wet and dry resin configurations under nitrogen at three temperatures. Work was initially conducted under contract number 24590-101-TSA-W000-00004 satisfying the needs defined in Appendix C of the Research and Technology Plan( ) TSS A-219 to evaluate the impact of storage conditions on RF resin performance. In February 2007, the contract mechanism was switched to Pacific Northwest National Laboratory (PNNL) Operating Contract DE-AC05-76RL01830.

Fiskum, Sandra K.; Arm, Stuart T.; Edwards, Matthew K.; Steele, Marilyn J.; Thomas, Kathie K.

2007-09-10

448

Development and properties of crystalline silicotitanate (CST) ion exchangers for radioactive waste applications  

Microsoft Academic Search

Crystalline silicotitanates (CSTs) are a new class of ion exchangers that were jointly invented by researchers at Sandia National Laboratories and Texas A&M University. One particular CST, known as TAM-5, is remarkable for its ability to separate parts-per-million concentrations of cesium from highly alkaline solutions (pH> 14) containing high sodium concentrations (>5M). It is also highly effective for removing cesium

James E. Miller; Norman E. Brown

1997-01-01

449

Formation of silver colloids in silver ion-exchanged soda-lime glasses during annealing  

Microsoft Academic Search

The structural and compositional changes of the soda-lime glasses during the formation of the silver colloids were analyzed by the X-ray Photoelectron Spectroscopy (XPS) in order to examine the silver colloid formation mechanism. The in situ behavior of silver and SiO2 networks on the surfaces of silver ion-exchanged soda-lime glasses during heating and cooling processes in ultra-high vaccum was monitored.

Paul W. Wang

1997-01-01

450

Treatment of waste oil\\/water emulsion by ultrafiltration and ion exchange  

Microsoft Academic Search

The present work investigates the treatment of waste drawing oil which is a high-strength waste oil\\/water emulsion commonly used in the cable and wire industries. Semi-batch ultrafiltration (UF) and ion exchange processes were employed to treat the waste oil\\/water emulsion. Experiments were conducted to examine the performance characteristics of the UF membranes of hydrophilic and hydrophobic types and of different

Sheng H. Lin; Wen J. Lan

1998-01-01

451

Paper Chromatography of Alkaloids Using Liquid Ion Exchangers as Developing Solvents  

Microsoft Academic Search

The RF vs. pH relationships of a number of more important alkaloids were determined for several solvent systems of the type oleic acid + diluting solvent\\/aqueous buffer solutions. The chromatographic data seem to indicate a high solvent power of the organic phase, belonging to the class of liquid ion exchangers. The regular RF vs. pH relationships obtained can be quantitatively

Edward Soczewi?aski; Grazyna Matysik; Halina Szumilo

1967-01-01

452

Decontamination of low-level wastewaters by continuous countercurrent ion exchange  

Microsoft Academic Search

A mobile pilot-scale continuous countercurrent ion-exchange (CCIX) system is operated at the Oak Ridge National Laboratory (ORNL) for the treatment of wastewaters that contain predominantly calcium, sodium, and magnesium bicarbonates and are slightly contaminated with ā¹Ā°Sr and Ā¹Ā³ā·Cs radioisotopes. A demonstration study is being conducted to evaluate the near-steady-state performance and feasibility of a pilot-scale CCIX column for the selective

R. Hall; S. M. Robinson; J. S. Watson

1990-01-01

453

Effect of Crown Ethers on Sr, Ba, and Ra Uptake by Tunnel?Structure Ion Exchangers  

Microsoft Academic Search

The effect of 15?crown?5 and 18?crown?6 ethers on the uptake of alkaline earth cations by tunnel?structure ion exchangers polyantimonic acid (PAA) and cryptomelane manganese dioxide (CMD) was examined. In the case of PAA, 15?crown?5 and especially 18?crown?6 strongly influence the uptake of Sr vs Ba and Ra. For separation of the Ra?Ba pair, the effect of the crown ethers is

Barbara Barto?; Aleksander Bilewicz

2006-01-01

454

Study on removing zinc from nickel electrolyte by ion-exchange  

Microsoft Academic Search

In the process of nickel production by diaphragm electrolysis, the quality of the product has been tremendously affected by\\u000a the content of zinc in the nickel electrolyte. Removing zinc from nickel electrolyte by ion-exchange is studied in the paper.\\u000a Resin D201 is selected as the resin for zinc removing. Effects of the operative parameters, such as temperature, pH value\\u000a and

Gui-qing Zhang; Qi-xiu Zhang; Lian-sheng Xiao; Bo-fan Gong

2000-01-01

455

Preparation of solid polymer electrolyte composites: investigation of the ion-exchange process  

Microsoft Academic Search

The rate of ion-exchange between an aqueous solution of platinum tetramine and a Nafion® 117 membrane in H+ form is studied. Experimental data are collected using extended X-ray absorption fine structure (EXAFS) spectroscopy in dispersive mode. Results are obtained for various platinum tetramine concentrations in the solution and different hydrodynamic regimes at the membrane-solution interface. A shift from a layer

P. Millet; F. Andolfatto; R. Durand

1995-01-01

456

New Er3+-doped phosphate glass for ion-exchanged waveguide amplifiers  

Microsoft Academic Search

A new Er(superscript 3+)-doped phosphate glass exhibiting an excellent durability in both boiling water and NaNO(subscript 3) molten salt is developed. The ion-exchange process of this glass is investigated by treating glass samples in a variety of salt baths with various exposure times. A planar waveguide with one mode at 1.54 micrometers and three modes at 632.8 nm is demonstrated.

Shibin Jiang; Tao Luo; Bor-Chyuan Hwang; Gualtiero Nunzi Conti; Michael J. Myers; Daniel L. Rhonehouse; Seppo Honkanen; Nasser Peyghambarian

1998-01-01

457

Removal of organic matter from effluents by Magnetic Ion Exchange (MIEX®)  

Microsoft Academic Search

Magnetic Ion Exchange Resin (MIEX®) is effective in removing the majority of organic carbon from biologically treated wastewater. It removed 77% of dissolved organic carbon (DOC) from synthetic wastewater when operated in batch mode using a MIEX® concentration of 10mL\\/L. A pseudo second-order reaction rate model namely the Ho model was used for the kinetic study and it was found

Tien Vinh Nguyen; Rong Zhang; Saravanamuthu Vigneswaran; Huu Hao Ngo; Jaya Kandasamy; Pram Mathes

2011-01-01

458

Combination of chlorine and magnetic ion exchange resin for drinking water treatment of algae  

Microsoft Academic Search

The effectiveness of a magnetic ion exchange resin (MIEX) for the treatment of Hongze Lake water in China was evaluated. The\\u000a kinetics of natural organic matter (NOM) removal at various MIEX doses and contact time, multiple-loading experiments, impacts\\u000a of MIEX prior to coagulation on coagulant demands and the effectiveness of combination of MIEX, pre-chlorination and coagulation\\u000a were investigated. Kinetic experimental

Zhi-gang Han; Wei Chen; Lei Li; Zhe Cao

2010-01-01

459

Experimental and theoretical investigations of steady and transient states in systems of ion exchange bipolar membranes  

Microsoft Academic Search

The electrochemical characteristics of one commercial bipolar ion exchange membrane and of two home-made bipolar membranes are investigated over a range of current densities up to 2kAm?2. Studies are performed using galvano-potentiometry (i\\/V) and impedance spectrometry methods. The temperature dependence of i\\/V curves enables the determination of the activation energies related to the overall electrochemical process of H+ and OH?

H. D Hurwitz; R Dibiani

2004-01-01

460

Fifteen years of operation with inorganic highly selective ion exchange materials  

Microsoft Academic Search

During latest fifteen years three highly selective inorganic ion exchange materials, CsTreat{sup R}, SrTreat{sup R}, and CoTreat, have been in full scale commercial use. All these materials have high capacity, and they give high decontamination factor (DF) and remarkably good volume reduction factor for storage and final disposal. A new material for antimony removal is currently coming for demonstration phase.

E. Tusa; R. Harjula; P. Yarnell

2007-01-01

461

Electrosorptive desalination by carbon nanotubes and nanofibres electrodes and ion-exchange membranes  

Microsoft Academic Search

A novel membrane capacitive deionization (MCDI) device, integrating both the advantages of carbon nanotubes and carbon nanofibers (CNTs–CNFs) composite film and ion-exchange membrane, was proposed with high removal efficiency, low energy consumption and low cost. The CNTs–CNFs film was synthesized by low pressure and low temperature thermal chemical vapor deposition. Several experiments were conducted to compare desalination performance of MCDI

Haibo Li; Yang Gao; Likun Pan; Yanping Zhang; Yiwei Chen; Zhuo Sun

2008-01-01

462

New magnetic materials obtained by ion-exchange reactions from non-magnetic layered perovskites  

Microsoft Academic Search

New layered magnetic materials, (MCl)Ca2Ta3O10 (M = Cu, Fe), have been prepared by ion-exchange reactions of non-magnetic perovskite derivatives, ACa2Ta3O10 (A = Rb, Li), in corresponding anhydrous molten salts. Powder x-ray diffraction patterns of the products are successfully indexed assuming tetragonal symmetry with cell dimensions a = 3.829 Å and c = 15.533 Å for Cu, and a = 3.822

H. Kageyama; L. Viciu; G. Caruntu; Y. Ueda; J. B. Wiley

2004-01-01

463

Cesium Removal from Simulated and Actual Hanford Tank Waste Using Ion Exchange  

Microsoft Academic Search

Effective cesium removal from Hanford tank wastes is presented using SuperLig 644, an elutable, organic ion exchanger. Test materials included simulant 241?AW?101, actual wastes from tanks 241?AP?101, 241?AN?102 combined with wash and leachate solutions from 241?C?104 solids, concentrated 241?AZ?102, 241?AZ?101, and 241?AP?104. Multiple process cycle testing was conducted using dual, small columns in series. Cesium (Cs) load and elution profiles

Sandra K. Fiskum; David L. Blanchard; Stuart T. Arm; Reid A. Peterson

2005-01-01

464

The load and release characteristics on a strong cationic ion-exchange fiber: kinetics, thermodynamics, and influences.  

PubMed

Ion-exchange fibers were different from conventional ion-exchange resins in their non-cross-linked structure. The exchange was located on the surface of the framework, and the transport resistance reduced significantly, which might mean that the exchange is controlled by an ionic reaction instead of diffusion. Therefore, this work aimed to investigate the load and release characteristics of five model drugs with the strong cationic ion-exchange fiber ZB-1. Drugs were loaded using a batch process and released in United States Pharmacopoeia (USP) dissolution apparatus 2. Opposing exchange kinetics, suitable for the special structure of the fiber, were developed for describing the exchange process with the help of thermodynamics, which illustrated that the load was controlled by an ionic reaction. The molecular weight was the most important factor to influence the drug load and release rate. Strong alkalinity and rings in the molecular structures made the affinity between the drug and fiber strong, while logP did not cause any profound differences. The drug-fiber complexes exhibited sustained release. Different kinds and concentrations of counter ions or different amounts of drug-fiber complexes in the release medium affected the release behavior, while the pH value was independent of it. The groundwork for in-depth exploration and further application of ion-exchange fibers has been laid. PMID:25114504

Yuan, Jing; Gao, Yanan; Wang, Xinyu; Liu, Hongzhuo; Che, Xin; Xu, Lu; Yang, Yang; Wang, Qifang; Wang, Yan; Li, Sanming

2014-01-01

465

The load and release characteristics on a strong cationic ion-exchange fiber: kinetics, thermodynamics, and influences  

PubMed Central

Ion-exchange fibers were different from conventional ion-exchange resins in their non-cross-linked structure. The exchange was located on the surface of the framework, and the transport resistance reduced significantly, which might mean that the exchange is controlled by an ionic reaction instead of diffusion. Therefore, this work aimed to investigate the load and release characteristics of five model drugs with the strong cationic ion-exchange fiber ZB-1. Drugs were loaded using a batch process and released in United States Pharmacopoeia (USP) dissolution apparatus 2. Opposing exchange kinetics, suitable for the special structure of the fiber, were developed for describing the exchange process with the help of thermodynamics, which illustrated that the load was controlled by an ionic reaction. The molecular weight was the most important factor to influence the drug load and release rate. Strong alkalinity and rings in the molecular structures made the affinity between the drug and fiber strong, while logP did not cause any profound differences. The drug–fiber complexes exhibited sustained release. Different kinds and concentrations of counter ions or different amounts of drug–fiber complexes in the release medium affected the release behavior, while the pH value was independent of it. The groundwork for in-depth exploration and further application of ion-exchange fibers has been laid. PMID:25114504

Yuan, Jing; Gao, Yanan; Wang, Xinyu; Liu, Hongzhuo; Che, Xin; Xu, Lu; Yang, Yang; Wang, Qifang; Wang, Yan; Li, Sanming

2014-01-01

466

Decontamination and dismantlement of the building 594 waste ion exchange facility at Argonne National Laboratory-East project final report.  

SciTech Connect

The Building 594 D&D Project was directed toward the following goals: Removal of any radioactive and hazardous materials associated with the Waste Ion Exchange Facility; Decontamination of the Waste Ion Exchange Facility to unrestricted use levels; Demolition of Building 594; and Documentation of all project activities affecting quality (i.e., waste packaging, instrument calibration, audit results, and personnel exposure) These goals had been set in order to eliminate the radiological and hazardous safety concerns inherent in the Waste Ion Exchange Facility and to allow, upon completion of the project, unescorted and unmonitored access to the area. The ion exchange system and the resin contained in the system were the primary areas of concern, while the condition of the building which housed the system was of secondary concern. ANL-E health physics technicians characterized the Building 594 Waste Ion Exchange Facility in September 1996. The characterization identified a total of three radionuclides present in the Waste Ion Exchange Facility with a total activity of less than 5 {micro}Ci (175 kBq). The radionuclides of concern were Co{sup 60}, Cs{sup 137}, and Am{sup 241}. The highest dose rates observed during the project were associated with the resin in the exchange vessels. DOE Order 5480.2A establishes the maximum whole body exposure for occupational workers at 5 rem (50 mSv)/yr; the administrative limit at ANL-E is 1 rem/yr (10 mSv/yr).

Wiese, E. C.

1998-11-23

467

Effects of ion exchange on stream solute fluxes in a basin receiving highway deicing salts  

USGS Publications Warehouse

At Fever Brook, a 1260-ha forested basin in central Massachusetts, highway deicing salt application increased the solute flux in streamflow by 120% above background flux (equivalent basis) during a 2-yr period. Attempts to isolate the nonsalt component of stream solute fluxes have commonly subtracted salt contributions based on the net Cl flux (Cl output in streamflow minus Cl input in precipitation). In these studies, any net Na flux in excess of the amount needed to balance the net Cl flux has been attributed to weathering. At Fever Brook, however, the net output of Na was less than the net output of Cl, suggesting a loss of Na within the basin. The Na sink was inferred to be cation exchange of Na for Ca and Mg in the soil. A method was developed to quantify the exchange based on a Na budget, which included an independent estimate of the Na flux from weathering. The amount of exchange was apportioned to Ca and Mg based on their relative concentrations in the stream. The background fluxes of Ca and Mg (i.e., those that would occur in the absence of deicing salts) were calculated by subtracting the amounts from ion exchange plus the much smaller direct contributions in deicing salts from the observed fluxes. Ion exchange and direct salt contributions increased the net output fluxes of Ca and Mg, each by 44% above background. In basins that receive deicing salts, failure to account for cation exchange thus may result in an underestimate of the flux of Na from weathering and overestimates of the fluxes of Ca and Mg from weathering.

Shanley, J.B.

1994-01-01

468

TRANSIENT HEAT TRANSFER ANALYSIS FOR ION-EXCHANGE WASTE REMOVAL PROCESS  

SciTech Connect

The small column ion exchange (SCIX) process treats low curie salt (LCS) waste before feeding it to the saltstone facility to be made into grout. Through this process, radioactive cesium from the salt solution is absorbed into the CST bed. A CST column loaded with radioactive cesium will generate significant heat from radiolytic decay. If engineering designs of the CST sorption column can not handle this thermal load, hot spots may develop locally within the column and degrade the performance of the ion-exchange process. The CST starts to degrade at about 80 to 85 C, and the CST completely changes to another material above 120 C. In addition, the process solution will boil around 130 C. If the column boiled dry, the sorbent could plug the column and require replacement of the column module. The objective of the present work is to compute temperature distributions across the column as a function of transit time after the initiation of accidents when there is loss of the salt solution flow in the CST column under abnormal conditions of the process operations. In this situation, the customer requested that the calculations should be conservative in that the model results would show the maximum centerline temperatures achievable by the CST design configurations. The thermal analysis results will be used to evaluate the fluid temperature distributions and the process component temperatures within the ion exchange system. This information will also assist in the system design and maintenance.

Lee, S.

2010-07-12

469

Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification.  

PubMed

Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m(2) g(-1)) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 ?mol g(-1) in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 ?mol g(-1) in an isotonic solution. The heparinized PPy-cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility. PMID:22298813

Ferraz, Natalia; Carlsson, Daniel O; Hong, Jaan; Larsson, Rolf; Fellström, Bengt; Nyholm, Leif; Strųmme, Maria; Mihranyan, Albert

2012-08-01

470

Increasing parvovirus filter throughput of monoclonal antibodies using ion exchange membrane adsorptive pre-filtration.  

PubMed

Pre-filtration using ion exchange membrane adsorbers can improve parvovirus filter throughput of monoclonal antibodies (mAbs). The membranes work by binding trace foulants, and although some antibody product also binds, yields > or =99% are easily achieved by overloading. Results show that foulant adsorption is dependent on pH and conductivity, but independent of scale and adsorber brand. The ability to use ion exchange membranes as pre-filters is significant because it provides a clean, well defined, chemically stable option for enhancing throughput. Additionally, ion exchange membranes facilitate characterization of parvovirus filter foulants. Examination of adsorber elution samples using sedimentation velocity analysis and SEC-MALS/QELS revealed the presence of high molecular weight species ranging from 8 to 13 nm in hydrodynamic radius, which are similar in size to parvoviruses and thus would be expected to plug the pores of a parvovirus filter. A study of two identical membranes in-series supports the hypothesis that the foulants are soluble, trace level aggregates in the feed. This study's significance lies in a previously undiscovered application of membrane chromatography, leading to a more cost effective and robust approach to parvovirus filtration for the production of monoclonal antibodies. PMID:20229510

Brown, Arick; Bechtel, Charity; Bill, Jerome; Liu, Hui; Liu, Jun; McDonald, Dan; Pai, Satyan; Radhamohan, Asha; Renslow, Ryan; Thayer, Brooke; Yohe, Stefan; Dowd, Chris

2010-07-01

471

Charge exchange spectroscopy system calibration for ion temperature measurement in KSTARa)  

NASA Astrophysics Data System (ADS)

The charge exchange spectroscopy (CES) system including collection assemblies, lens design, and cassettes for the KSTAR experiment was installed to obtain profiles of the ion temperature and the toroidal rotation velocity from charge exchange emission between plasma ions and beam neutrals near the plasma axis by using a modulated neutral beam and a background system. We can measure the charge exchange spectra of an impurity line such as the 529 nm line of carbon VI to get ion temperature and rotation profiles in KSTAR. The CES and background systems will have absolute intensity and spectral calibrations using a calibrated source and various spectral lamps. The calibration was done inside the tokamak after all CES systems are installed and the optical systems are slid into the cassettes. This requires that the diagnostic systems are installed near the vacuum vessel inside the cryostat maintaining the superconducting state of the superconducting coils. Repeated spectral calibrations of the spectrometer and charge coupled device for CES will be made in the diagnostic room during the experimental campaign. We show a detailed description of the KSTAR CES system, how to calibrate, and the results of calibration.

Ko, Won-Ha; Lee, Hyungho; Seo, Dongcheol; Kwon, Myeun

2010-10-01

472

Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification  

PubMed Central

Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m2 g?1) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 ?mol g?1 in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 ?mol g?1 in an isotonic solution. The heparinized PPy–cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility. PMID:22298813

Ferraz, Natalia; Carlsson, Daniel O.; Hong, Jaan; Larsson, Rolf; Fellstrom, Bengt; Nyholm, Leif; Str?mme, Maria; Mihranyan, Albert

2012-01-01

473

Nitrate removal from electro-oxidized landfill leachate by ion exchange.  

PubMed

Treatment of landfill leachates by electrochemical oxidation led to the complete removal of chemical oxygen demand and ammonium nitrogen. However, as result of the ammonium oxidation, the partial formation of nitrate ions was observed. Ion exchange technology was investigated as a polishing step in the treatment of landfill leachates. Removal of nitrate from aqueous solutions was studied using two selective anion exchangers: Purolite A 520E and Purolite A 300, under a fixed bed configuration. The following aspects of the ion exchange system were experimentally analyzed: (i) the influence of the presence of other competitive anions in solution, sulfate and chloride, during the loading step, (ii) the breakthrough point and resin saturation as a function of chloride concentration in the feed stream and, (iii) the efficiency of the regeneration step working with NaCl solutions at several concentrations. After a comparison of the experimental results, it was concluded that the resin Purolite A 300 showed a better behavior. Experimental analysis of the equilibrium isotherms made it possible to determine the equilibrium constant (K=3.21) and the maximum capacity (q(max)=183mgg(-1)), important parameters in the design of the treatment process. PMID:18805640

Primo, Oscar; Rivero, Marķa J; Urtiaga, Ana M; Ortiz, Inmaculada

2009-05-15

474

Unified superresolution experiments and stochastic theory provide mechanistic insight into protein ion-exchange adsorptive separations  

PubMed Central

Chromatographic protein separations, immunoassays, and biosensing all typically involve the adsorption of proteins to surfaces decorated with charged, hydrophobic, or affinity ligands. Despite increasingly widespread use throughout the pharmaceutical industry, mechanistic detail about the interactions of proteins with individual chromatographic adsorbent sites is available only via inference from ensemble measurements such as binding isotherms, calorimetry, and chromatography. In this work, we present the direct superresolution mapping and kinetic characterization of functional sites on ion-exchange ligands based on agarose, a support matrix routinely used in protein chromatography. By quantifying the interactions of single proteins with individual charged ligands, we demonstrate that clusters of charges are necessary to create detectable adsorption sites and that even chemically identical ligands create adsorption sites of varying kinetic properties that depend on steric availability at the interface. Additionally, we relate experimental results to the stochastic theory of chromatography. Simulated elution profiles calculated from the molecular-scale data suggest that, if it were possible to engineer uniform optimal interactions into ion-exchange systems, separation efficiencies could be improved by as much as a factor of five by deliberately exploiting clustered interactions that currently dominate the ion-exchange process only accidentally. PMID:24459184

Kisley, Lydia; Chen, Jixin; Mansur, Andrea P.; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Chen, Wen-Hsiang; Dhamane, Sagar; Willson, Richard C.; Landes, Christy F.

2014-01-01

475

Use of aminocarboxylic ion-exchangers to purify ammonium molybdate and tungstate solutions  

SciTech Connect

A number of new, commercial aminocarboxylic ion-exchangers have appeared in recent years, but with no studies on whether they can be used to prepare high purity molybdenum and tungsten compounds. This paper reports properties of those domestic aminocarboxylic ion-exchangers most promising for the purification of ammonium molybdate (AM) and ammonium tungstate (AT) solutions. Changes in the concentration of magnesium, copper, nickel, and iron-irons in solution after their static contact with ion exchangers were determined by complexometric titration except for iron, which was analyzed radiometrically by the activity of added Fe 59. Monitoring the dynamic elimination of calcium from AM and AT solutions was also done radiometrically with the Ca 45 isotope, and that of the other elements by a spectrochemical method. It is shown that a pH between 8.5 and 9.0 is the most favorable condition for simultaneously freeing AM solutions from alkaline earth, divalent transition metals, and iron impurities. The AT solutions are stable only in the presence of 25-30 g/liter of free ammonia, corresponding to pH 9.7-10.0.

Blokhin, A.A.; Semenov, M.I.; Taushkanov, V.P.; Vakolenko, V.A.

1986-06-01

476

Core-ion temperature measurement of the ADITYA tokamak using passive charge exchange neutral particle energy analyzer  

NASA Astrophysics Data System (ADS)

Core-ion temperature measurements have been carried out by the energy analysis of passive charge exchange (CX) neutrals escaping out of the ADITYA tokamak plasma (minor radius, a = 25 cm and major radius, R = 75 cm) using a 45° parallel plate electrostatic energy analyzer. The neutral particle analyzer (NPA) uses a gas cell configuration for re-ionizing the CX-neutrals and channel electron multipliers (CEMs) as detectors. Energy calibration of the NPA has been carried out using ion-source and ?E/E of high-energy channel has been found to be ˜10%. Low signal to noise ratio (SNR) due to VUV reflections on the CEMs was identified during the operation of the NPA with ADITYA plasma discharges. This problem was rectified by upgrading the system by incorporating the additional components and arrangements to suppress VUV radiations and improve its VUV rejection capabilities. The noise rejection capability of the NPA was experimentally confirmed using a standard UV-source and also during the plasma discharges to get an adequate SNR (>30) at the energy channels. Core-ion temperature Ti(0) during flattop of the plasma current has been measured to be up to 150 eV during ohmically heated plasma discharges which is nearly 40% of the average core-electron temperature (typically Te(0) ˜ 400 eV). The present paper describes the principle of tokamak ion temperature measurement, NPA's design, development, and calibration along with the modifications carried out for minimizing the interference of plasma radiations in the CX-spectrum. Performance of the NPA during plasma discharges and experimental results on the measurement of ion-temperature have also been reported here.

Pandya, Santosh P.; Ajay, Kumar; Mishra, Priyanka; Dhingra, Rajani D.; Govindarajan, J.

2013-02-01

477

Core-ion temperature measurement of the ADITYA tokamak using passive charge exchange neutral particle energy analyzer  

SciTech Connect

Core-ion temperature measurements have been carried out by the energy analysis of passive charge exchange (CX) neutrals escaping out of the ADITYA tokamak plasma (minor radius, a= 25 cm and major radius, R= 75 cm) using a 45 Degree-Sign parallel plate electrostatic energy analyzer. The neutral particle analyzer (NPA) uses a gas cell configuration for re-ionizing the CX-neutrals and channel electron multipliers (CEMs) as detectors. Energy calibration of the NPA has been carried out using ion-source and {Delta}E/E of high-energy channel has been found to be {approx}10%. Low signal to noise ratio (SNR)