Sample records for ratio ion exchange

  1. High Aspect Ratio Ion Exchange Resin Bed – Hydraulic Results for Spherical Resin Beads

    Microsoft Academic Search

    Mark R. Duignan; Charles A. Nash; Timothy M. Punch

    2008-01-01

    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

  2. ION EXCHANGE

    EPA Science Inventory

    The IONEX program's name is a contraction of "ion exchange." The IONEX program performs calculations related to removing radium and/or uranium from water with the ion exchange process. IONEX provides a quick method of calculating whether a proposed ion exchange process will m...

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

    SciTech Connect

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

    2007-09-27

    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.

  4. Modulation of Na+/Mg²+ exchanger stoichiometry ratio by Cl? ions in basolateral rat liver plasma membrane vesicles.

    PubMed

    Cefaratti, C; Romani, A

    2011-05-01

    The Na+/Mg²+ exchanger represents the main Mg²+ extrusion mechanism operating in mammalian cells including hepatocytes. We have previously reported that this exchanger, located in the basolateral domain of the hepatocyte, promotes the extrusion of intravesicular trapped Mg²+ for extravesicular Na+ with ratio 1. This electrogenic exchange is supported by the accumulation of tetraphenyl-phosphonium within the vesicles at the time when Mg²+ efflux occurs. In this present study, the role of extra- and intra-vesicular Cl? on the Na+/Mg²+ exchange ratio was investigated. The results reported here suggest that Cl? ions are not required for the Na+ to Mg²+ exchange to occur, but the stoichiometry ratio of the exchanger switches from electrogenic (1Na(in)+ :1Mg(out)²+) in the presence of intravesicular Cl? to electroneutral (2Na(in)+ :1 Mg(out)²+) in their absence. In basolateral liver plasma membrane vesicles loaded with MgCl? labeled with ³?Cl?, a small but significant Cl? efflux (~30 nmol Cl?/mg protein/1 min) is observed following addition of NaCl or Na-isethionate to the extravesicular medium. Both Cl? and Mg²+ effluxes are inhibited by imipramine but not by amiloride, DIDS, niflumic acid, bumetanide, or furosemide. In vesicles loaded with Mg-gluconate and stimulated by Na-isethionate, an electroneutral Mg²+ extrusion is observed. Taken together, these results suggest that the Na+/Mg²+ exchanger can operate irrespective of the absence or the presence of Cl? in the extracellular or intracellular environment. Changes in trans-cellular Cl? content, however, can affect the modus operandi of the Na+/Mg²+ exchanger, and consequently impact "cellular" Na+ and Mg²+ homeostasis as well as the hepatocyte membrane potential. PMID:21234652

  5. Ion exchange technology assessment report

    SciTech Connect

    Duhn, E.F.

    1992-01-01

    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.

  6. Ion exchange technology assessment report

    SciTech Connect

    Duhn, E.F.

    1992-12-31

    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.

  7. Electrically switched ion exchange

    SciTech Connect

    Lilga, M.A. [Pacific Northwest National Lab., Richland, WA (United States); Schwartz, D.T.; Genders, D.

    1997-10-01

    A variety of waste types containing radioactive {sup 137}Cs are found throughout the DOE complex. These waste types include water in reactor cooling basins, radioactive high-level waste (HLW) in underground storage tanks, and groundwater. Safety and regulatory requirements and economics require the removal of radiocesium before these wastes can be permanently disposed of. Electrically Switched Ion Exchange (ESIX) is an approach for radioactive cesium separation that combines IX and electrochemistry to provide a selective, reversible, and economic separation method that also produces little or no secondary waste. In the ESIX process, an electroactive IX film is deposited electrochemically onto a high-surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. For cesium, the electroactive films under investigation are ferrocyanides, which are well known to have high selectivities for cesium in concentrated sodium solutions. When a cathode potential is applied to the film, Fe{sup +3} is reduced to the Fe{sup +2} state, and a cation must be intercalated into the film to maintain charge neutrality (i.e., Cs{sup +} is loaded). Conversely, if an anodic potential is applied, a cation must be released from the film (i.e., Cs{sup +} is unloaded). Therefore, to load the film with cesium, the film is simply reduced; to unload cesium, the film is oxidized.

  8. Vitrification of ion exchange resins

    DOEpatents

    Cicero-Herman, Connie A. (Aiken, SC); Workman, Rhonda Jackson (North Augusta, SC)

    2001-01-01

    The present invention relates to vitrification of ion exchange resins that have become loaded with hazardous or radioactive wastes, in a way that produces a homogenous and durable waste form and reduces the disposal volume of the resin. The methods of the present invention involve directly adding borosilicate glass formers and an oxidizer to the ion exchange resin and heating the mixture at sufficient temperature to produce homogeneous glass.

  9. Electrically Switched Cesium Ion Exchange

    SciTech Connect

    JPH Sukamto; ML Lilga; RK Orth

    1998-10-23

    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.

  10. Grafted methylenediphosphonate ion exchange resins

    DOEpatents

    Trochimcznk, A.W.; Gatrone, R.C.; Alexandratos, S.; Horwitz, E.P.

    1997-04-08

    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 phosphorus. The pendent groups have the formula as shown in the patent 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.

  11. FUNDAMENTAL STUDIES ON THE ION EXCHANGE SEPARATION OF ISOTOPES. IV. SEPARATION FACTOR OF LITHIUM ISOTOPES USING ION EXCHANGER

    Microsoft Academic Search

    H. Kakihana; T. Nomura; Y. Mori

    1961-01-01

    The ion exchange separatuon factors of lithium isotopes in LiCl and LiOH ; solutions were determined with differently cross-linked sulfonated styrene-; divinylbenzene copolymers and a synthetic inorganic ion exchanger, lonite C, ; (zurconuum phosphate type). The isotopic ratios of lithuum were measured by a ; mass spectrometer using the thermionic method. The highest separation factor, ; l.022, was obtained for

  12. Resonant charge exchange and the transport of ions at high electric-field to gas-density ratios (E\\/N) in argon, neon, and helium

    Microsoft Academic Search

    M. V. V. S. Rao; R. J. van Brunt; J. K. Olthoff

    1996-01-01

    Translational kinetic-energy distributions of singly and doubly charged ions have been measured at high electric-field to gas-density ratios (E\\/N) up to 5.0×10-17 V m2 (50 kTd) in diffuse, parallel-plate Townsend discharges in Ar, Ne, and He using an ion energy analyzer-mass spectrometer. For Ar+ in Ar and Ne+ in Ne when E\\/N <2.0×10-17 V m2 and for He+ in He

  13. Ion microprobe analysis of oxygen isotope ratios in quartz from Skye granite: healed micro-cracks, fluid flow, and hydrothermal exchange

    Microsoft Academic Search

    John W. Valley; Colin M. Graham

    1996-01-01

    Quartz grains in hydrothermally altered granites from the Isle of Skye are highly heterogeneous and not equilibrated in oxygen\\u000a isotope ratio at the 20??m scale. Ion microprobe analysis of one grain shows a gradient of 13‰ over 400??m and a greater range\\u000a in ?\\u000a 18O than all quartz previously analyzed on the Isle of Skye. Other crystals from the same

  14. Pharmaceutical Applications of Ion-Exchange Resins

    ERIC Educational Resources Information Center

    Elder, David

    2005-01-01

    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…

  15. Ion exchange purification of scandium

    DOEpatents

    Herchenroeder, L.A.; Burkholder, H.R.

    1990-10-23

    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. 2 figs.

  16. Ion exchange purification of scandium

    DOEpatents

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

    1990-10-23

    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.

  17. PRTR ion exchange vault column sampling

    SciTech Connect

    Cornwell, B.C.

    1995-03-14

    This report documents ion exchange column sampling and Non Destructive Assay (NDA) results from activities in 1994, for the Plutonium Recycle Test Reactor (PRTR) ion exchange vault. The objective was to obtain sufficient information to prepare disposal documentation for the ion exchange columns found in the PRTR Ion exchange vault. This activity also allowed for the monitoring of the liquid level in the lower vault. The sampling activity contained five separate activities: (1) Sampling an ion exchange column and analyzing the ion exchange media for purpose of waste disposal; (2) Gamma and neutron NDA testing on ion exchange columns located in the upper vault; (3) Lower vault liquid level measurement; (4) Radiological survey of the upper vault; and (5) Secure the vault pending waste disposal.

  18. XAFS Studies of Silver Environments in Ion-Exchanged Glasses

    SciTech Connect

    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

    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)

  19. Titania bound sodium titanate ion exchanger

    DOEpatents

    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

    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.

  20. Ion exchange resins for metal finishing wastes

    Microsoft Academic Search

    Juzer Jangbarwala

    1997-01-01

    Many ion exchange techniques applicable to the metal finishing wastes are not used owing to the significant dilution from rinsing and the front and tail portions of the elution curve. Some of these proven techniques were revisited with the thought that new, improved ion exchange systems generating less regenerant waste can make these applications economically viable.

  1. Ion exchange in the nuclear industry

    SciTech Connect

    Bibler, J.P.

    1990-01-01

    Ion exchange is used in nearly every part of the nuclear fuel cycle -- from the purification of uranium from its ore to the final recovery of uranium and transmutation products. Ion exchange also plays a valuable role in the management of nuclear wastes generated in the fuel cycle.

  2. Ion exchange in the nuclear industry

    SciTech Connect

    Bibler, J.P.

    1990-12-31

    Ion exchange is used in nearly every part of the nuclear fuel cycle -- from the purification of uranium from its ore to the final recovery of uranium and transmutation products. Ion exchange also plays a valuable role in the management of nuclear wastes generated in the fuel cycle.

  3. 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

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

    2014-07-15

    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

  4. Ion exchanger from chemically modified banana leaves.

    PubMed

    El-Gendy, Ahmed A; Mohamed, Samar H; Abd-Elkader, Amal H

    2013-07-25

    Cation exchangers from chemically modified banana leaves have been prepared. Banana leaves were treated with different molarities of KMnO4 and cross linked with epichlorohydrin and their effect on metal ion adsorption was investigated. Phosphorylation of chemically modified banana leaves was also studied. The metal ion uptake by these modified banana leaves was clarified. Effect of different varieties, e.g. activation of produced cation exchanger, concentration of metal ions was also investigated. Characterization of the prepared ion exchangers by using infrared and thermal analysis was also taken in consideration. PMID:23768590

  5. Simultaneous removal and recovery of cadmium and cyanide ions in synthetic wastewater by ion exchange

    Microsoft Academic Search

    Seung Jai Kim; Ki Hyun Lira; Yueng Guen Park; Jin Hwan Kim; Sung Yong Cho

    2001-01-01

    Simultaneous removal and recovery of cyanide and cadmium ions using a strong-base anion exchange resin was studied on the\\u000a basis of formation of Cd-CN complexes at high pH in synthetic wastewater containing cyanide and cadmium ions. Strong-base\\u000a anion exchange resin particles, of Dowex1X8-50, were contacted with synthetic aqueous solutions. For different molar ratios\\u000a between cyanide and cadmium, ion exchange characteristics

  6. Development of novel fuel ion ratio diagnostic techniques

    SciTech Connect

    Korsholm, S. B.; Stejner, M.; Bindslev, H.; Furtula, V.; Leipold, F.; Meo, F.; Michelsen, P. K.; Moseev, D.; Nielsen, S. K.; Salewski, M. [Association EURATOM-Risoe DTU, 4000 Roskilde (Denmark); Conroy, S.; Ericsson, G. [Association EURATOM-VR, Uppsala University, 75120 Uppsala (Sweden); Gorini, G.; Tardocchi, M. [Association EURATOM-ENEA CNR, 20125 Milano (Italy); Hellermann, M. von; Lischtschenko, O.; Delabie, E. [Association EURATOM-FOM, 3430 BE Nieuwegein (Netherlands); Jaspers, R. J. E. [Department of Applied Physics, Fusion Group, Eindhoven University of Technology, 5612 AZ Eindhoven (Netherlands)

    2010-10-15

    To overcome the challenge of measuring the fuel ion ratio in the core ({rho}<0.3) of ITER, a coordinated effort aiming at developing diagnostic techniques has been initiated. The investigated techniques are novel uses or further development of existing methods such as charge exchange recombination spectrometry, neutron spectrometry, and collective Thomson scattering. An overview of the work on the three diagnostic techniques is presented.

  7. Porous Ceramic Spheres from Ion Exchange Resin

    NASA Technical Reports Server (NTRS)

    Dynys, Fred

    2005-01-01

    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.

  8. Gold recovery with ion exchange used resins

    Microsoft Academic Search

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

    2001-01-01

    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

  9. MODELING RESULTS FROM CESIUM ION EXCHANGE PROCESSING WITH SPHERICAL RESINS

    Microsoft Academic Search

    C. Nash; T. Hang; S. Aleman

    2011-01-01

    Ion exchange modeling was conducted at the Savannah River National Laboratory to compare the performance of two organic resins in support of Small Column Ion Exchange (SCIX). In-tank ion exchange (IX) columns are being considered for cesium removal at Hanford and the Savannah River Site (SRS). The spherical forms of resorcinol formaldehyde ion exchange resin (sRF) as well as a

  10. Gas permeation properties of ion-exchanged ZSM-5 zeolite membranes

    Microsoft Academic Search

    Kanna Aoki; Vu A Tuan; John L Falconer; Richard D Noble

    2000-01-01

    Hydrothermally synthesized, ZSM-5 zeolite membranes (Si\\/Al=25 and 600) were ion exchanged with H+, Na+, K+, Cs+, Ca2+ and Ba2+ cations, and the membranes were stable after exchange. Their gas permeation properties were measured over the temperature range of 323–523 K. Both the Si\\/Al ratio and the exchanged ion size affected the separation performance. For the membrane with a Si\\/Al ratio

  11. 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 ...

  12. Influence of charge exchange on the collection of the laser produced ions

    NASA Astrophysics Data System (ADS)

    Hasegawa, Shuichi; Takei, Manabu; Suzuki, Atsuyuki; Kurosawa, Hitoshi

    2001-12-01

    We evaluated influences of charge exchange on ion collection of laser isotope separation of uranium. We made a two-dimensional code based on fluid dynamics taking the charge exchange term into consideration. Parametric study was performed in terms of electric amplitude, ion density, and electron temperature. In addition to parallel electrode arrangement, calculations were performed for ?- and M-type arrangements. The ratio of charge exchanged ions is found to largely depend on the collection time.

  13. Ion thruster charge-exchange plasma flow

    NASA Technical Reports Server (NTRS)

    Carruth, M. R., Jr.; Gabriel, S. B.; Kitamura, S.

    1982-01-01

    The electron bombardment ion thruster has been under development for a number of years and during this time, studies of the plasmas produced by the thrusters and their interactions with spacecraft have been evaluated, based on available data. Due to diagnostic techniques used and facility effects, there is uncertainty as to the reliability of data from these early studies. This paper presents data on the flow of the charge-exchange plasma produced just downstream of the thruster's ion optics. The 'end-effect' of a cylindrical Langmuir probe is used to determine ion density and directed ion velocity. Results are compared with data obtained from a retarding potential analyzer-Faraday cup.

  14. Graphene/Ionic Liquid Composite Films and Ion Exchange

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

    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.

  15. Graphene/Ionic Liquid Composite Films and Ion Exchange

    PubMed Central

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

    2014-01-01

    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

  16. Calcium isotope fractionation in ion-exchange chromatography

    Microsoft Academic Search

    W. A. Russell; D. A. Papanastassiou

    1978-01-01

    Significant fractionation of the isotopes of calcium has been observed during elution through short ion-exchange columns packed with Dowex 50W-X8 resin. A double isotopic tracer was used to provide correction for instrumental fractionation effects. The absolute ⁴°Ca\\/⁴⁴Ca ratio is determined by this method to 0.05% and provides a measure of the fractionation of all Ca isotopes. It is found that

  17. Thermal Analysis of LANL Ion Exchange Column

    SciTech Connect

    Laurinat, J.E.

    1999-06-16

    This document reports results from an ion exchange column heat transfer analysis requested by Los Alamos National Laboratory (LANL). The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades.

  18. Electrically switched cesium ion exchange. FY 1997 annual report

    SciTech Connect

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

    1997-09-01

    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.

  19. Magnetic ion exchange: Is there potential for international development? 

    E-print Network

    Neale, Peta A.; Schäfer, Andrea

    2009-01-01

    Magnetic ion exchange (MIEX®) is an ion exchange resin developed as an additive to existing water treatment plants where additional organic matter is to be removed. The smaller size, magnetic properties and simple ...

  20. Isotope effects of neodymium in different ligands exchange systems studied by ion exchange displacement chromatography

    PubMed Central

    Ismail, Ibrahim; Fawzy, Ahmed S.; Ahmad, Mohammad I.; Aly, Hisham F.; Nomura, Masao; Fujii, Yasuhiko

    2012-01-01

    The isotope effects of neodymium in Nd-glycolate ligand exchange system were studied by using ion exchange chromatography. The separation coefficients of neodymium isotopes, ?’s, were calculated from the observed isotopic ratios at the front and rear boundaries of the neodymium adsorption band. The values of separation coefficients of neodymium isotopes, ?’s, for the Nd-glycolate ligand exchange system were compared with those of Nd-malate and Nd-citrate, which indicated that the isotope effects of neodymium as studied by the three ligands takes the following direction Malate > Citrate > Glycolate. This order agrees with the number of available sites for complexation of each ligand. The values of the plate height, HETP of Nd in Nd-ligand exchange systems were also calculated. PMID:25685410

  1. Isotope effects of neodymium in different ligands exchange systems studied by ion exchange displacement chromatography.

    PubMed

    Ismail, Ibrahim; Fawzy, Ahmed S; Ahmad, Mohammad I; Aly, Hisham F; Nomura, Masao; Fujii, Yasuhiko

    2013-03-01

    The isotope effects of neodymium in Nd-glycolate ligand exchange system were studied by using ion exchange chromatography. The separation coefficients of neodymium isotopes, ?'s, were calculated from the observed isotopic ratios at the front and rear boundaries of the neodymium adsorption band. The values of separation coefficients of neodymium isotopes, ?'s, for the Nd-glycolate ligand exchange system were compared with those of Nd-malate and Nd-citrate, which indicated that the isotope effects of neodymium as studied by the three ligands takes the following direction Malate > Citrate > Glycolate. This order agrees with the number of available sites for complexation of each ligand. The values of the plate height, HETP of Nd in Nd-ligand exchange systems were also calculated. PMID:25685410

  2. Porous solid ion exchange wafer for immobilizing biomolecules

    SciTech Connect

    Arora, Michelle B. (Woodridge, IL); Hestekin, Jamie A. (Morton Grove, IL); Lin, YuPo J. (Naperville, IL); St. Martin, Edward J. (Libertyville, IL); Snyder, Seth W. (Lincolnwood, IL)

    2007-12-11

    A porous solid ion exchange wafer having a combination of a biomolecule capture-resin and an ion-exchange resin forming a charged capture resin within said wafer. Also disclosed is a porous solid ion exchange wafer having a combination of a biomolecule capture-resin and an ion-exchange resin forming a charged capture resin within said wafer containing a biomolecule with a tag. A separate bioreactor is also disclosed incorporating the wafer described above.

  3. SWELLING OF A CHELATING MACROPOROUS RESIN DURING METAL ION EXCHANGE

    Microsoft Academic Search

    F. Mijangos; M. Ortueta; I. Aguirre

    2000-01-01

    The kinetics of heavy metal ion exchange onto a commercial chelating resin was investigated from the standpoint of the swelling-shrinking experienced by the resin bead during the overall ion exchange process. Temporal measurements of the volume variations were carried out for every step of an operational cycle, metal load, elution and regeneration of the ion exchanger, using a microreactor mainly

  4. Ion exchange as a tertiary treatment 

    E-print Network

    Westervelt, Ronald David

    1968-01-01

    . The effect of ion exchange on other character- istics of the waste water, such as turbidity and color was also noted. The first flow scheme studied (Flow Scheme A) consisted of sand filtration and anion exchange. The final effluent was first passed... be of great value in reducing the algaL and 17 bacterial growths, since values of more than 10 mg. /l. of phosphorus in waste water effluents are not uncommon. This is particularly true for Texas lakes and streams where silt is present and light...

  5. Polymethylmethacrylate open tubular ion exchange columns: nondestructive measurement of very small ion exchange capacities.

    PubMed

    Zhang, Min; Yang, Bingcheng; Dasgupta, Purnendu K

    2013-08-20

    We describe an approach to prepare an open tubular ion exchange (OTIE) column by coating a monolayer of anion exchange nanoparticle to a 16-20 ?m bore polymethylmethacrylate (PMMA) capillary. The latex nanoparticle was electrostatically attached to carboxylate groups on the inner wall of capillary, pretreated with strong base for hydrolyzing the ester. Several approaches to nondestructively measure ion exchange capacities (IEC) of the columns were examined: (a) adsorption-desorption of an intensely fluorescent ion, e.g. fluorescein, and off-line fluorometry, (b) loading a weakly retained ion (e.g., IO3(-)), frontal displacement by a strongly bound ion (e.g., Cl(-)), and online optical or conductometric boundary detection, and (c) similar to the above except displacement being accompanied by reaction (e.g., acid-base titration). To our knowledge, this is the first time on-column titration has been used to measure capacities. By using different pH displacer solutions, we demonstrate for the first time the possibility of pKa-differentiated ion exchange capacity measurements. The cation exchange capacity of bare PMMA capillaries was on the order of 1 pequiv/mm(2) with little dependence on time and temperature of hydrolysis conditions. After AS18 latex coating, the strong base anion exchange capacity was on the order of 10 pequiv/mm(2), very close to what would be estimated on the basis of monolayer coverage of the surface by individual latex particles. The latex used contained a significant, additional amount of weak base character, about the same as the strong base ion exchange capacity. PMID:23875750

  6. PRTR ion exchange vault water removal

    SciTech Connect

    Ham, J.E.

    1995-11-01

    This report documents the removal of radiologically contaminated water from the Plutonium Recycle Test Reactor (PRTR) ion exchange vault. Approximately 57,000 liters (15,000 gallons) of water had accumulated in the vault due to the absence of a rain cover. The water was removed and the vault inspected for signs of leakage. No evidence of leakage was found. The removal and disposal of the radiologically contaminated water decreased the risk of environmental contamination.

  7. Ion exchange selectivity of a perfluorosulfonate ionomer 

    E-print Network

    Wilkerson, James Edward

    1983-01-01

    of Advisory Committee: Dr. C. R. Martin The ion exchange selectivity of Nafion was evaluated. Two separate series of homologous cations were separated. A series of viologens, methyl, benzyl, and heptyl, were sepa- rated by utilizing tetramethyl ammonium... chloride with an organic modifier, methanol. Another series of homologous cations were also separated. This series consisted of ethyl, propyl, butyl, pentyl, and hexyl pyridinium bromides. Any combination of these five cations could be separated...

  8. Ion-Exchange Chromatography in Alcohol

    Microsoft Academic Search

    K. K. Carroll

    1955-01-01

    IN the technique of ion-exchange chromatography, the order in which compounds are eluted from a column depends basically upon differences in their ionization constants; but other factors modify and in many instances reverse the expected order1. This is illustrated in Fig. 1, where the elution peaks of a number of acids from a `Dowex' resin are plotted against their pK

  9. Comparison of chromatographic ion-exchange resins

    Microsoft Academic Search

    Arne Staby; Inge Holm Jensen; Inger Mollerup

    2000-01-01

    A comparative study has been undertaken on various strong anion-exchangers to investigate the pH dependence, titration curves, efficiency, binding strength, and dynamic capacity of the chromatographic resins. The resins tested included: Macro-Prep 25Q, TSK-Gel Q-5PW-HR, Poros QE\\/M, Q Sepharose FF, Q HyperD 20, Q Zirconia, Source 30Q, Fractogel EMD TMAE 650s, and Express-Ion Q. Testing was performed with five different

  10. Ion Exchange Temperature Testing with SRF Resin

    SciTech Connect

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

    2012-03-01

    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.

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

    SciTech Connect

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

    1981-10-20

    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.

  12. Exploration of Ion-Exchanged Glass for Seals Applications 

    E-print Network

    Ghanbari, Roushan

    2012-10-19

    , the technology selected for investigation was ion-exchanged glass. Ion-exchanged glass is relatively inexpensive, has high strength, and can be used in a variety of applications. If identical pieces of glass are exchanged under the same conditions and subjected...

  13. Evaluation of Leachable Behavior from Ion Exchange Resins

    Microsoft Academic Search

    Hiroo IGARASHI; Yusaku NISHIMURA; Katsumi OHSUMI; Shunsuke UCHIDA; Tsuneo MATSUI

    1999-01-01

    The elution rate of leachables from ion exchange resin, which is used in condensate demineralizers and is one of several major sources of organic compounds in BWR cooling water, was measured. Properties of the leachables and elution rate depended on the kind of ion exchange resin and the years of use. The organic compounds elution rate of cation exchange resin

  14. Synthesis of perrhenic acid using ion exchange method

    Microsoft Academic Search

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

    2007-01-01

    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

  15. New Metal Niobate and Silicotitanate Ion Exchangers: Development and Characterization

    Microsoft Academic Search

    Alexandra Navrotsky; Mary Lou Balmer; Tina M. Nenoff; Yali Su

    2003-01-01

    This renewal proposal outlines our current progress and future research plans for ion exchangers: novel metal niobate and silicotitanate ion exchangers and their ultimate deployment in the DOE complex. In our original study several forms (including Cs exchanged) of the heat treated Crystalline Silicotitanates (CSTs) were fully characterized by a combination of high temperature synthesis and phase identification, low temperature

  16. High pressure ratio cryocooler with integral expander and heat exchanger

    Microsoft Academic Search

    J. A. Crunkleton; J. L. Smith Jr.; Y. Iwasa

    1988-01-01

    A new 1 W, 4.2 K cryocooler is under development that is intended to miniaturize helium temperature refrigeration systems using a high-pressure-ratio Collins-type cycle. The configuration resulted from optimization studies of a saturated vapor compression (SCV) cycle that employs miniature parallel-plate heat exchangers. The basic configuration is a long displacer in a close-fitting, thin-walled cylinder. The displacer-to-cylinder gap is the

  17. Comparison of activated carbon and ion-exchange resins in recovering copper from cyanide leach solutions

    Microsoft Academic Search

    X. Dai; P. L. Breuer; M. I. Jeffrey

    2010-01-01

    The use of activated carbon and ion-exchange resins for recovering copper cyanide from gold leach solutions is compared in detail. When using activated carbon, the overall cyanide-to-copper ratio should be reduced to ?2 to achieve the most effective adsorption. This can be accomplished by dissolving metallic copper into the leach solution. However when using ion-exchange resins to recover the copper,

  18. Concept of advanced spent fuel reprocessing based on ion exchange

    Microsoft Academic Search

    Tatsuya Suzuki; Kazuyuki Takahashi; Masanobu Nogami; Masao Nomura; Yasuhiko Fujii; Masaki Ozawa; Shinichi Koyama; Hitosi Mimura; Reiko Fujita

    2007-01-01

    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.

  19. Biodegradation of ion-exchange media

    SciTech Connect

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

    1988-01-01

    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.

  20. Ion exchange capacity of Nafion and Nafion composites

    Microsoft Academic Search

    Ta-Yung Chen; Johna Leddy

    2000-01-01

    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

  1. Ion-Exchangeable, Electronically Conducting Layered Perovskite Oxyfluorides

    E-print Network

    Ion-Exchangeable, Electronically Conducting Layered Perovskite Oxyfluorides Yoji Kobayashi@chem.psu.edu Abstract: Cation-exchangeable d0 layered perovskites are amenable to intercalation, exfoliation of mixed-valent perovskites. Conversely, electronically and magnetically interesting layered perovskites

  2. Ion exchange of cesium by crystalline silico-titanates

    SciTech Connect

    Zheng, Zhixin; Anthony, R.G. [Texas A& M Univ., College Station, TX (United States). Dept. of Chemical Engineering; Miller, J.E.; Trudell, D. [Sandia National Labs., Albuquerque, NM (United States)

    1995-12-01

    The crystalline silico-titanates developed by the Department of Chemical Engineering at Texas A&M University, Sandia National Laboratories and UOP exhibits extremely high ion exchange selectivity for removing cesium from aqueous defense wastes. Based on experimental data and structure studies, a competitive ion exchange model was proposed to predict the ion exchange performance in different simulated waste solutions. The predicted distribution coefficients were within 10% of the experimentally determined values.

  3. Conducting polymers as ion-exchangers for water purification

    Microsoft Academic Search

    C. Weidlich; K.-M. Mangold; K. Jüttner

    2001-01-01

    The charging and discharging processes of conducting polymers, e.g. polypyrrole, are accompanied by the exchange of ions. This effect was used for the development of an electrochemically switchable ion-exchanger for water purification, especially for softening drinking water. The ion-exchange behaviour and capacity of electrochemically and chemically prepared polypyrrole (PPy) in dependence on the incorporated counterions are characterised using an electrochemical

  4. Evaluation of Elution Parameters for Cesium Ion Exchange Resins

    Microsoft Academic Search

    Ingrid E. Burgeson; Jaquetta R. Deschane; Bryan J. Cook; David L. Blanchard; Dennis R. Weier

    2006-01-01

    Cesium ion exchange is one of the planned processes for treating and disposing of waste at the U.S. Department of Energy Hanford Site. Radioactive supernatant liquids from the waste tanks will undergo ultrafiltration, followed by cesium ion exchange using a regenerable organic ion exchange resin. Two resins, SuperLig644 and a resorcinol?formaldehyde resin, are being evaluated for cesium removal and cesium

  5. Effects of ionizing radiation on modern ion exchange materials

    SciTech Connect

    Marsh, S.F.; Pillay, K.K.S.

    1993-10-01

    We review published studies of the effects of ionizing radiation on ion exchange materials, emphasizing those published in recent years. A brief overview is followed by a more detailed examination of recent developments. Our review includes styrene/divinylbenzene copolymers with cation-exchange or anion-exchange functional groups, polyvinylpyridine anion exchangers, chelating resins, multifunctional resins, and inorganic exchangers. In general, strong-acid cation exchange resins are more resistant to radiation than are strong-base anion exchange resins, and polyvinylpyridine resins are more resistant than polystyrene resins. Cross-linkage, salt form, moisture content, and the surrounding medium all affect the radiation stability of a specific exchanger. Inorganic exchangers usually, but not always, exhibit high radiation resistance. Liquid ion exchangers, which have been used so extensively in nuclear processing applications, also are included.

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

    SciTech Connect

    RAMSEY AA; THORSON MR

    2010-12-28

    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.

  7. Pyrolysis of Spent Ion Exchange Resins - 12210

    SciTech Connect

    Braehler, Georg; Slametschka, Rainer [NUKEM Technologies GmbH (Germany)

    2012-07-01

    Organic ion exchangers (IEX) play a major and increasing role in the reactor coolant and other water purification processes. During their operation time they receive significant amounts of radioactivity, making their disposal, together with their organic nature, as medium active waste challenging. Processes applied so far do not eliminate the organic matter, which is unwanted in disposal facilities, or, if high temperatures are applied, raise problems with volatile radionuclides. NUKEM Technologies offers their well introduces process for the destruction of spent solvent (TBP), the pebble bed pyrolysis, now for the treatment of spent IEX (and other problematic waste), with the following benefits: the pyrolysis product is free of organic matter, and the operation temperature with approx. 500 deg. C keeps Cs radionuclides completely in the solid residue. (authors)

  8. Waste treatment by selective mineral ion exchanger

    SciTech Connect

    Polito, Aurelie [Areva NC - BUA STMI, 1 route de la Noue - 91196 Gif sur Yvette, Cedex (France)

    2007-07-01

    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 synthetic inorganic compounds prepared from very pure raw materials. Different types of RANs (POLYAN, OXTAIN, Fe-Cu, Fe-CoK, Si-Fe-CoK) can be used to trap a large number of radioactive elements in contaminated effluents. Different implementations could be applied depending on technical conditions. STMI's offers consist in building global solution and preliminary design of installation either in dispersed form (batch) or in column (cartridge filtration). Those products are used all over the world not only in the nuclear business (Canada, US, Belgium, France...) but also in other fields. Indeed, it provides competitive solutions to many domains of application especially water pollution control, liquid waste treatment in the nuclear business by decreasing the activity level of waste. The following paper will focus on the theoretical principle of the mineral exchanger, its implementation and the feed back collected by STMI. (author)

  9. CHLORIDE REMOVAL FROM KRAFT LIQUORS USING ION EXCHANGE TECHNOLOGY

    Microsoft Academic Search

    Craig J. Brown; Aleksander Russer; Michael Paleologou; Roxaré Thompson; Naceur Jemaa

    A new system has been developed for removal of chloride contamination from kraft process liquors. The compact, skid-mounted system which utilizes ion exchange columns only 24 inches in height, is shown to be capable of removing 90-99% of the chloride from a wide variety of sources including dissolved ESP catch, oxidized white liquor, spent bleach scrubber liquors, spent ion exchange

  10. Spectral hole-burning in Eu 3+ ion exchanged ??-alumina

    Microsoft Academic Search

    Takeshi Hattori; Ryotaro Yagi; Kazuhiro Aso; Mareo Ishigame

    2000-01-01

    Spectral hole-burning has been observed in Eu3+ ion exchanged Na ??-alumina. There are two types of persistent holes at different burning wavelengths: One is with a complex band shape and the other with a simple Lorentzian shape. The latter persistent hole, with a simple Lorentzian shape, can be burned up to 70 K for 90% exchanged sample of Eu3+ ions.

  11. Electrolytic desorption of silver from ion-exchange resins

    Microsoft Academic Search

    Slavica Pavlini?; Ivan Piljac

    1998-01-01

    Strong base ion-exchange resins Lewatit M 500 and Lewatit M 504 have steep ascending parts of isotherm curves in the range of low silver concentration in solution and can be used for silver extraction from plating rinsing effluents. Common elution methods are very inefficient for silver removal from strong base ion-exchange resins. Hence, the silver regeneration was performed by the

  12. Evaluation of electrochemical ion exchange for cesium elution

    Microsoft Academic Search

    J. D. Bontha; D. E. Kurath; J. E. Surma; M. F. Buehler

    1996-01-01

    Electrochemical elution was investigated as an alternative method to acid elution for the desorption of cesium from loaded ion exchange resins. The approach was found to have several potential advantages over existing technologies, in particular, electrochemical elution eliminates the need for addition of chemicals to elute cesium from the ion exchange resin. Also, since, in the electrochemical elution process the

  13. HEAT TRANSFER ANALYSIS FOR ION-EXCHANGE COLUMN SYSTEM

    Microsoft Academic Search

    S. Lee; W. King

    2011-01-01

    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

  14. Radiation testing of organic ion exchange resins

    SciTech Connect

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

    1995-09-01

    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}.

  15. Protein adsorption on novel acrylamido-based polymeric ion exchangers

    Microsoft Academic Search

    Alan K. Hunter; Giorgio Carta

    2000-01-01

    Uptake kinetics and breakthrough behavior were determined for bovine serum albumin (BSA) and ?-chymotrypsinogen (?CHY) in new polymeric ion-exchange media based on acrylamido monomers. Two anion exchangers and a cation exchanger were investigated. As shown in Part I of this work, the two anion exchangers have different morphologies. The first one, BRX-Q, comprises a low-density gel with a matrix of

  16. Electroplating rinse waste water treatment by ion exchange

    Microsoft Academic Search

    I. Dobrevsky; M. Dimova-Todorova; T. Panayotova

    1997-01-01

    Purification of copper containing waste waters from electroplating plants by means of different ion exchange units has been studied. The copper containing waste water with a range of copper concentration 55–60 mg\\/l, pH 3.3–3.5 has been treated of following schemes: (I) Weak base anion exchanger (OH-form) — weak acid cation exchanger (H-form) — strong base anion exchanger (OH-form); and (II)

  17. Synthesis of layered sodium lanthanum selenide through ion exchange reactions

    SciTech Connect

    Butts, Laura J.; Strickland, Nicholas [Department of Chemistry, Texas State University - San Marcos, 601 University Drive, San Marcos, TX 78666 (United States); Martin, Benjamin R. [Department of Chemistry, Texas State University - San Marcos, 601 University Drive, San Marcos, TX 78666 (United States)], E-mail: bmartin@txstate.edu

    2009-04-02

    Layered hexagonal KLaSe2 ({alpha}-NaFeO{sub 2}-type) was synthesized using the reactive flux method and analyzed by powder XRD to determine its lattice constants (space group R-3m, a = 4.40508(5) A, c = 22.7838(5) A). NaLaSe{sub 2}, which normally crystallizes as a disordered rock salt structure with mixed Na+/La + 3 sites, was synthesized through a solid state ion exchange reaction at 585 deg. C from a 1:3 molar ratio mixture of KLaSe{sub 2}:NaI. The product of this reaction was hexagonally layered NaLaSe{sub 2} (space group R-3m, a = 4.3497(3) A, c = 20.808(2) A) isostructural to KLaSe{sub 2}. This product was analyzed by comparison with members of the set of solid solutions Na{sub (1-x)}K{sub (x)}LaSe{sub 2} to confirm that the extent ion exchange in this reaction was complete. Cubic (disordered) NaLaSe{sub 2} was also reacted with KI to yield the poorly crystalline hexagonally layered product with the approximate formula Na{sub 0.79}K{sub 0.21}LaSe{sub 2}.

  18. FRACTIONATION OF LITHIUM ISOTOPES IN ION EXCHANGE CHROMATOGRAPHY WITH TITANIUM PHOSPHATE EXCHANGER

    Microsoft Academic Search

    K. Ooi; Y. Miyai; Y. Makita; H. Kanoh

    1999-01-01

    Ion exchange chromatography of lithium was carried out to study the lithium isotope effect in an aqueous ion-exchange system, using titanium phosphate exchangers granulated with polyvinyl chloride or an inorganic binder. The sample granulated with PVC showed significant isotope fractionations when a 0.05 M (NH4)2CO3 solution was used as an eluent. The lighter isotope Li was preferentially fractionated into the

  19. IMPROVEMENTS RELATING TO ION-EXCHANGE PROCESSES AND PLANTS

    Microsoft Academic Search

    T. V. Arden; J. B. Davis; L. A. Sargent

    1961-01-01

    An ion cxchange apparatus is designed in which a pulp or suspension ; undergoes ion exchange by moving upwards through a bed of ion cxchange beads. ; The bed is supported by the pulp, with the pulp flow rate being decreased at the ; pulp-bed interface so that the heavier, loaded pulp may move downwards into the ; pulp but

  20. Hydrolyzed Poly(acrylonitrile) Electrospun Ion-Exchange Fibers

    PubMed Central

    Jassal, Manisha; Bhowmick, Sankha; Sengupta, Sukalyan; Patra, Prabir K.; Walker, Douglas I.

    2014-01-01

    Abstract A potential ion-exchange material was developed from poly(acrylonitrile) fibers that were prepared by electrospinning followed by alkaline hydrolysis (to convert the nitrile group to the carboxylate functional group). Characterization studies performed on this material using X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier-Transform infra-red spectroscopy, and ion chromatography confirmed the presence of ion-exchange functional group (carboxylate). Optimum hydrolysis conditions resulted in an ion-exchange capacity of 2.39?meq/g. Ion-exchange fibers were used in a packed-bed column to selectively remove heavy-metal cation from the background of a benign, competing cation at a much higher concentration. The material can be efficiently regenerated and used for multiple cycles of exhaustion and regeneration. PMID:24963270

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

    E-print Network

    Nguyen, Luan Thanh

    1994-01-01

    with different valences. Ion exchangers carrying exchangeable cations are called cation exchangers, and ion exchangers carrying exchangeable anions are called anion exchangers. In addition, amphoteric ion exchangers are capable of both cation and/or anion..., are used to remove the cesium cation from a standard solution containing 5. 7 M Na+, 5. 1 M NO, , and 0. 6 M OH . The cesium cation are exchanged with sodium cation from the exchangers. The experimental data are then fitted with different theoretical...

  2. Interpenetrating polymer network ion exchange membranes and method for preparing same

    DOEpatents

    Alexandratos, Spiro D. (Knoxville, TN); Danesi, Pier R. (Vienna, AT); Horwitz, E. Philip (Naperville, IL)

    1989-01-01

    Interpenetrating polymer network ion exchange membranes include a microporous polymeric support film interpenetrated by an ion exchange polymer and are produced by absorbing and polymerizing monomers within the support film. The ion exchange polymer provides ion exchange ligands at the surface of and throughout the support film which have sufficient ligand mobility to extract and transport ions across the membrane.

  3. Ion-exchanged glass waveguide technology: a review

    NASA Astrophysics Data System (ADS)

    Tervonen, Ari; West, Brian R.; Honkanen, Seppo

    2011-07-01

    We review the history and current status of ion exchanged glass waveguide technology. The background of ion exchange in glass and key developments in the first years of research are briefly described. An overview of fabrication, characterization and modeling of waveguides is given and the most important waveguide devices and their applications are discussed. Ion exchanged waveguide technology has served as an available platform for studies of general waveguide properties, integrated optics structures and devices, as well as applications. It is also a commercial fabrication technology for both passive and active wave-guide components.

  4. 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 ...

  5. 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...

  6. Tc-99 Ion Exchange Resin Testing

    SciTech Connect

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

    2010-08-01

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

  7. Electrochemical properties of sulfonated PEEK used for ion exchange membranes

    Microsoft Academic Search

    Xianfeng Li; Zhe Wang; Hui Lu; Chengji Zhao; Hui Na; Chun Zhao

    2005-01-01

    Membranes with improved selectivity, stability, and non-fouling properties will be important in future chemical and waste treatment applications. Sulfonated poly(ether ether ketone)s (S-PEEKs) based membranes have been studied due to their good mechanical properties, thermal stability and ion exchange property. In this study, S-PEEKs based membranes were evaluated for ion exchange application. The microstructures of S-PEEKs membranes were studied by

  8. Observations of solar wind ion charge exchange in the comet Halley coma

    NASA Technical Reports Server (NTRS)

    Fuselier, S. A.; Shelley, E. G.; Goldstein, B. E.; Goldstein, R.; Neugebauer, M.; Ip, W.-H.; Balsiger, H.; Reme, H.

    1991-01-01

    Giotto Ion Mass Spectrometer/High Energy Range Spectrometer (IMS/HERS) observations of solar wind ions show charge exchange effects and solar wind compositional changes in the coma of comet Halley. As the comet was approached, the He(++) to proton density ratio increased until about 1 hour before closest approach after which time it decreased. Abrupt increases in this ratio were also observed in the beginning and near the end of the so-called Mystery Region (8.6 - 5.5(10)(exp 5) km from the comet along the spacecraft trajectory). These abrupt increases in the density ratio were well correlated with enhanced fluxes of keV electrons as measured by the Giotto plasma electron spectrometer. The general increase and then decrease of the He(++) to proton density ratio is quantitatively consistent with a combination of the addition of protons of cometary origin to the plasma and loss of plasma through charge exchange of protons and He(++). In general agreement with the solar wind proton and He(++) observations, solar wind oxygen and carbon ions were observed to charge exchange from higher to lower charge states with decreasing distance to the comet. The more abrupt increases in the He(++) to proton and the He(++) to O(6+) density ratios in the mystery region require a change in the solar wind ion composition in this region while the correlation with energetic electrons indicates processes associated with the comet.

  9. MODELING RESULTS FROM CESIUM ION EXCHANGE PROCESSING WITH SPHERICAL RESINS

    SciTech Connect

    Nash, C.; Hang, T.; Aleman, S.

    2011-01-03

    Ion exchange modeling was conducted at the Savannah River National Laboratory to compare the performance of two organic resins in support of Small Column Ion Exchange (SCIX). In-tank ion exchange (IX) columns are being considered for cesium removal at Hanford and the Savannah River Site (SRS). The spherical forms of resorcinol formaldehyde ion exchange resin (sRF) as well as a hypothetical spherical SuperLig{reg_sign} 644 (SL644) are evaluated for decontamination of dissolved saltcake wastes (supernates). Both SuperLig{reg_sign} and resorcinol formaldehyde resin beds can exhibit hydraulic problems in their granular (nonspherical) forms. SRS waste is generally lower in potassium and organic components than Hanford waste. Using VERSE-LC Version 7.8 along with the cesium Freundlich/Langmuir isotherms to simulate the waste decontamination in ion exchange columns, spherical SL644 was found to reduce column cycling by 50% for high-potassium supernates, but sRF performed equally well for the lowest-potassium feeds. Reduced cycling results in reduction of nitric acid (resin elution) and sodium addition (resin regeneration), therefore, significantly reducing life-cycle operational costs. These findings motivate the development of a spherical form of SL644. This work demonstrates the versatility of the ion exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. The value of a resin with increased selectivity for cesium over potassium can be assessed for further development.

  10. Low loss bends in K+ ion-exchanged waveguides

    Microsoft Academic Search

    Olav Gaute Helleso; Philippe Gerard; Pierre Benech; Roger Rimet

    1994-01-01

    Single-mode channel waveguides are made by K+ ion-exchange in soda-lime glass microscope slides and B1664 glass. Bend losses are studied experimentally and reduced with an optimisation of the exchange temperature and the exchange time. The measured bend losses are compared to simulations. The smallest radius giving low losses is reduced from 30 mm to 10 mm using microscope slides instead

  11. ELUTION OF URANIUM VALUES FROM ION EXCHANGE RESINS

    Microsoft Academic Search

    1959-01-01

    A process is described for eluting complex uranium ions absorbed on ion ; exchange resins. The resin is subjected to the action of an aqueous eluting ; solution contuining sulfuric acid and an alkali metal, ammonium, or magnesium ; chloride or nitrate, the elution being carried out until the desired amount of ; the uranium is removed from the resin.

  12. ESIEX-Electrical Swing Ion Exchange a Process Coupling Ion Exchange, Carbonic Acid Elution and Electrochemical Regeneration

    Microsoft Academic Search

    W. Lu; G. Grévillot; L. Muhr

    2011-01-01

    A process which can be used for purification of a peptide is presented. This process is called ESIEX: Electrical Swing Ion Exchange. The principle of this process is based on a three steps cyclic mode, which avoids using pH buffers or generating wastes. The experimental set-up consists of an electrodialysis apparatus in which the cells are filled with anion exchange

  13. ESIEX-Electrical Swing Ion Exchange a Process Coupling Ion Exchange, Carbonic Acid Elution, and Electrochemical Regeneration

    Microsoft Academic Search

    W. Lu; G. Grévillot; L. Muhr

    2011-01-01

    A process which can be used for purification of a peptide is presented. This process is called ESIEX: Electrical Swing Ion Exchange. The principle of this process is based on a three steps cyclic mode, which avoids using pH buffers or generating wastes. The experimental set-up consists of an electrodialysis apparatus in which the cells are filled with anion exchange

  14. Microsecond pulsed hydrogen/deuterium exchange of electrosprayed ubiquitin ions stored in a linear ion trap.

    PubMed

    Rajabi, Khadijeh

    2015-02-01

    A pulse of D2O vapour on the order of microseconds is allowed to react with the +6 to +9 charge states of ubiquitin confined in a linear ion trap (LIT). Two envelopes of peaks are detected for the ions of ubiquitin, corresponding to the ions that exchange more quickly and more slowly. The deuterium uptake of the protonated sites on ubiquitin ions accounts for the ion population with the fast exchange. The hydrogen/deuterium exchange (HDX) kinetics of ubiquitin ions trapped in the LIT for 200 ms showed comparable structural transitions to those trapped for 300 ms. When ions are trapped for longer, i.e. up to 2000 ms, mainly the slow exchanging ion population is detected. In all experiments the +7 ions exchange the most, suggesting a short distance between the surface protonated sites and nearby charged sites, and concomitantly high accessibility of surface protonated sites towards D2O. The +6 ions are more compact than the +7 ions but have one fewer protonated site, therefore fewer surface availabilities for D2O attack. The data suggest that the +6 ions keep most of their solution-phase contacts intact while the hydrophobic core is slightly interrupted in the +7 ions, possibly due to the exposure of charged His68 that is normally buried in the hydrophobic pocket. The +8 and +9 ions have more protonated sites but are less compact than the +7 ions because of Coulombic repulsion, resulting in a larger distance between the protonated sites and the basic sites. The data indicate that the HDX mechanism of ions with the slower exchange corresponding to the second envelope of peaks is primarily governed via a relay mechanism. The results suggest that the pulsed HDX MS method is sampling a population of ubiquitin ions with a similar backbone fold to the solution. PMID:25553956

  15. Desalination of brackish waters using ion-exchange media

    SciTech Connect

    Pless, J.D.; Philips, M.L.F.; Voigt, J.A.; Moore, D.; Axness, M.; Krumhansl, J.L.; Nenoff, T.M. [Sandia National Labs., Albuquerque, NM (United States)

    2006-06-21

    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 around 3 mequiv g{sup -1}. The cation-exchange material, an amorphous aluminosilicate permutite-like material, (Na{sub x}+2yAl{sub x}Si{sub 1}-xO{sub 2+y}), has an IEC of around to 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 = similar to 11 000) with a high carbonate concentration used an additional lime softening step and resulted in a decreased TDS of 600 ppm.

  16. Desalination of brackish waters using ion exchange media.

    SciTech Connect

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

    2005-01-01

    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.

  17. Ion-exchange and iontophoresis-controlled delivery of apomorphine.

    PubMed

    Malinovskaja, Kristina; Laaksonen, Timo; Kontturi, Kyösti; Hirvonen, Jouni

    2013-04-01

    The objective of this study was to test a drug delivery system that combines iontophoresis and cation-exchange fibers as drug matrices for the controlled transdermal delivery of antiparkinsonian drug apomorphine. Positively charged apomorphine was bound to the ion-exchange groups of the cation-exchange fibers until it was released by mobile counter-ions in the external solution. The release of the drug was controlled by modifying either the fiber type or the ionic composition of the external solution. Due to high affinity of apomorphine toward the ion-exchanger, a clear reduction in the in vitro transdermal fluxes from the fibers was observed compared to the respective fluxes from apomorphine solutions. Changes in the ionic composition of the donor formulations affected both the release and iontophoretic flux of the drug. Upon the application of higher co-ion concentrations or co-ions of higher valence in the donor formulation, the release from the fibers was enhanced, but the iontophoretic steady-state flux was decreased. Overall, the present study has demonstrated a promising approach using ion-exchange fibers for controlling the release and iontophoretic transdermal delivery of apomorphine. PMID:23207323

  18. ION EXCHANGE PERFORMANCE OF TITANOSILICATES, GERMANATES AND CARBON NANOTUBES

    SciTech Connect

    Alsobrook, A.; Hobbs, D.

    2013-04-24

    This report presents a summary of testing the affinity of titanosilicates (TSP), germanium-substituted titanosilicates (Ge-TSP) and multiwall carbon nanotubes (MWCNT) for lanthanide ions in dilute nitric acid solution. 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. The MWCNT exhibited much lower affinities than the K-TSP in dilute nitric acid solutions. However, the MWCNT are much more chemically stable to concentrated nitric acid solutions and, therefore, may candidates for ion exchange in more concentrated nitric acid solutions. This technical report serves as the deliverable documenting completion of the FY13 research milestone, M4FT-13SR0303061 – measure actinide and lanthanide distribution values in nitric acid solutions with sodium and potassium titanosilicate materials.

  19. Charge exchange of metastable 2D oxygen ions with molecular oxygen - A new source of thermospheric O2/+/ ions

    NASA Technical Reports Server (NTRS)

    Torr, D. G.; Torr, M. R.; Rusch, D. W.; Nier, A. O.; Kayser, D.; Hanson, W. B.; Hoffman, J. H.; Donahue, K.

    1979-01-01

    Reactions involving metastable ions are difficult to study in the laboratory. Much new information on these reactions has been derived from satellite measurements of aeronomic parameters. In this paper, Atmosphere Explorer D data are used to study charge exchange of metastable O(+)(2D) ions with O2. Using direct measurements of the O2 at 200 km to compute O2 densities at 300 km and supporting ionic concentrations and temperature observations, we find the rate coefficient for this reaction to be 1 + or - 0.6 times 10 to the minus 9th cu cm/sec. The process constitutes a significant source of O2(+) ions in the F2 layer at times when the N2 and O2 densities are enhanced. This finding leads to the conclusion that charge exchange with O2 must be a major sink for O(+)(2D) and an important source of O2(+) ions in the E region, because of the increase in the O2 concentration/N2 concentration ratio with decreasing altitude. The results imply that 80% of all O(+) ions formed in the E region are converted to O2(+) and that only about 20% of the metastable O(+) ions are converted into N2(+) through charge exchange with N2.

  20. Properties of a Novel Ion-Exchange Film

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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.

  1. Branching ratios for the dissociative recombination of hydrocarbon ions

    NASA Astrophysics Data System (ADS)

    Mitchell, J. B. A.; Angelova, G.; Rebrion-Rowe, C.; Novotny, O.; LeGarrec, J. L.; Bluhme, H.; Seiersen, K.; Svendsen, A.; Andersen, L. H.

    2005-01-01

    Branching ratios for the recombination of hydrocarbon ions have been measured using the ASTRID storage ring electron cooler. These studies have concentrated upon the competition of channels where the carbon skeleton of the molecule is left intact with other channels where carbon-carbon bonds are broken. A discussion of the effects of initial molecular structure on the resulting dissociation pattern is given.

  2. MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS

    SciTech Connect

    Hobbs, D.; Visser, A.; Bridges, N.

    2011-09-20

    This project seeks to determine if (1) inorganic-based ion exchange materials or (2) electrochemical methods in ionic liquids can be exploited to provide effective Am and Cm separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of inorganic-based ion-exchange materials for actinide and lanthanide ions. Furthermore, we seek to determine whether ionic liquids can serve as the electrolyte that would enable formation of higher oxidation states of Am and other actinides. Experiments indicated that pH, presence of complexants and Am oxidation state exhibit significant influence on the uptake of actinides and lanthanides by layered sodium titanate and hybrid zirconium and tin phosphonate ion exchangers. The affinity of the ion exchangers increased with increasing pH. Greater selectivity among Ln(III) ions with sodium titanate materials occurs at a pH close to the isoelectric potential of the ion exchanger. The addition of DTPA decreased uptake of Am and Ln, whereas the addition of TPEN generally increases uptake of Am and Ln ions by sodium titanate. Testing confirmed two different methods for producing Am(IV) by oxidation of Am(III) in ionic liquids (ILs). Experimental results suggest that the unique coordination environment of ionic liquids inhibits the direct electrochemical oxidation of Am(III). The non-coordinating environment increases the oxidation potential to a higher value, while making it difficult to remove the inner coordination of water. Both confirmed cases of Am(IV) were from the in-situ formation of strong chemical oxidizers.

  3. Synthesis, characterization, and ion exchange properties of a sodium nonatitanate, Na4Ti9O20.xH2O 

    E-print Network

    Graziano, Gina Marie

    1998-01-01

    of the sodium nonatitanate ion exchanger, Na4Ti9O2OoxH20, such as the Na and Ti reactants, the heating time, oven temperature, Na:Ti mole ratio, and heating method, were altered and their effects on Sr2' ion exchange selectivity were examined. For example...

  4. $K^-/K^+$ ratios in relativistic heavy-ion collisions

    E-print Network

    G. Q. Li; G. E. Brown

    1998-04-07

    We study $K^-/K^+$ ratios as a function of centrality (participant nucleon number), transverse mass ($m_t$), and rapidity, in heavy-ion collisions at beam energies between 1A and 2A GeV. We use the relativistic transport model that includes expicitly the strangeness degrees of freedom and consider two scenarios for kaon properties in dense matter, one with and one without medium modifications of their properties. In both scenarios, The $K^-/K^+$ ratio does not change very much with the centrality, while the $K/\\pi$ and ${\\bar K}/\\pi$ ratios increase with increasing centrality. Significant differences are predicted, both in magnitudes and shapes, for the $m_t$ spectra and rapidity distributions of $K^-/K^+$ ratio. Experimental measurement of these ratios, currently under investigation by the FOPI, KaoS, E866, and E895 collaborations, will be useful in revealing the kaon in-medium properties.

  5. Thermodynamics of Ion Exchange in Clays

    Microsoft Academic Search

    R. P. Townsend

    1984-01-01

    As an introduction, the general thermodynamic treatments for binary cation exchange are reviewed. The normal choice of standard states for the cations in the clay phase, and commonly used thermodynamic formulations with different scales of measurement are both discussed. The definition of standard states for the clay phase which is due to Gaines & Thomas (J. chem. Phys. 21, 714

  6. FLUORESCENCE EFFECTS IN ION EXCHANGE RESINS

    Microsoft Academic Search

    T. R. Flint; G. G. Eichholz

    1961-01-01

    Available as Can. Dept. Mines and Tech. Surveys, Mines Branch ; Resesrch Report R-91, 25. Fluorescence under ultraviolet illumination was ; observed in anion and cation exchange resins when in the unloaded state. The ; fluorescence decreases rapidly in intensity as the resin is loaded and this ; process is shown to offer a practical method for controlling the loading

  7. Coccolith B/Ca ratios using SIMS ion probe analysis

    NASA Astrophysics Data System (ADS)

    Stoll, H.; Shimizu, N.; Langer, G.

    2009-04-01

    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 initial results of B/Ca analyses of coccoliths produced in laboratory culture under variable carbonate ion concentrations. Due to the impossibility of physically separating the micron-sized coccoliths from non-coccolith sediment material in quantities large enough for TIMS or ICP-MS analysis of B/Ca, eventual analysis of coccolith B/Ca from the fossil record will need to be conducted on individually picked coccoliths on the ion probe as is currently done for other trace element (eg. Sr/Ca) ratios. Hence, we employ the CAMECA IMS 1280 ion probe at the Northeast National Ion Microprobe Facility at Woods Hole Oceanographic Institution to measure B/Ca in coccoliths from cultures. We evaluated cleaning methods using a synthetic cleaning target (crushed marble) contaminated with noncalcifying algae. Cleaning is crucial for obtaining accurate B/Ca ratios and precluding sample charging. B/Ca ratios of different genera of modern coccoliths range from 5 to 25 umol/mol, 3 to 10fold lower than planktic foraminifera or abiogenic calcite precipitated in seawater in the same pH range. These low ratios suggest much more restricted uptake of B into the algae cell in the vesicle calcification used by coccolithophores, compared with the seawater vacuole calcification typical of foraminifera. Different coccolith species grown at the same pH exhibit different B/Ca ratios. One species, Coccolithus pelagicus, cultured at a range of pH conditions from 7.7 to 8.4, exhibits no significant change in B/Ca ratios across the range of pH. One explanation is pH homeostasis at the calcification site. In possible support of pH homeostasis, the degree of calcification of this species was insensitive to variable CO2 and pH conditions in published experiments. We will also present results from strains of Emiliania huxleyi grown at different pH, for which more acidic pH resulted in depressed calcification.

  8. On the electron-ion temperature ratio established by collisionless shocks

    NASA Astrophysics Data System (ADS)

    Vink, Jacco; Broersen, Sjors; Bykov, Andrei; Gabici, Stefano

    2015-07-01

    Astrophysical shocks are often collisionless shocks, in which the changes in plasma flow and temperatures across the shock are established not through Coulomb interactions, but through electric and magnetic fields. An open question about collisionless shocks is whether electrons and ions each establish their own post-shock temperature (non-equilibration of temperatures), or whether they quickly equilibrate in the shock region. Here we provide a simple, thermodynamic, relation for the minimum electron-ion temperature ratios that should be expected as a function of Mach number. The basic assumption is that the enthalpy-flux of the electrons is conserved separately, but that all particle species should undergo the same density jump across the shock, in order for the plasma to remain charge neutral. The only form of additional electron heating that we allow for is adiabatic heating, caused by the compression of the electron gas. These assumptions result in an analytic treatment of expected electron-ion temperature ratio that agrees with observations of collisionless shocks: at low sonic Mach numbers, Ms ? 2, the electron-ion temperature ratio is close to unity, whereas for Mach numbers above Ms ? 60 the electron-ion temperature ratio asymptotically approaches a temperature ratio of Te/Ti = me/ ? mi ?. In the intermediate Mach number range the electron-ion temperature ratio scales as Te/Ti ? Ms-2. In addition, we calculate the electron-ion temperature ratios under the assumption of adiabatic heating of the electrons only, which results in a higher electron-ion temperature ratio, but preserves the Te/Ti ? Ms-2 scaling. We also show that for magnetised shocks the electron-ion temperature ratio approaches the asymptotic value Te/Ti = me/ ? mi ? for lower magnetosonic Mach numbers (Mms), mainly because for a strongly magnetised shock the sonic Mach number is larger than the magnetosonic Mach number (Mms ? Ms). The predicted scaling of the electron-ion temperature ratio is in agreement with observational data for magnetosonic Mach numbers between 2 and 10, but for supernova remnants the relation requires that the inferred Mach numbers for the observations are overestimated, perhaps as a result of upstream heating in the cosmic-ray precursor. In addition to predicting a minimal electron-ion temperature ratio, we also heuristically incorporate ion-electron heat exchange at the shock, quantified with a dimensionless parameter ?, which is the fraction of the enthalpy-flux difference between electrons and ions that is used for equilibrating the electron and ion temperatures. Comparing the model to existing observations in the solar system and supernova remnants suggests that the data are best described by ? ? 5%, but also provides a hint that the Mach number of some supernova remnant shocks may have been overestimated; perhaps as a result of heating in the cosmic-ray precursor.

  9. Rupture loop annex ion exchange RLAIX vault deactivation

    SciTech Connect

    Ham, J.E.; Harris, D.L., Westinghouse Hanford

    1996-08-01

    This engineering report documents the deactivation, stabilization and final conditions of the Rupture Loop Annex Ion Exchange (RLAIX) Vault located northwest of the 309 Building`s Plutonium Recycle Test Reactor (PRTR). Twelve ion exchange columns, piping debris, and column liquid were removed from the vault, packaged and shipped for disposal. The vault walls and floor were decontaminated, and portions of the vault were painted to fix loose contamination. Process piping and drains were plugged, and the cover blocks and rain cover were installed. Upon closure,the vault was empty, stabilized, isolated.

  10. Comparison of chromatographic ion-exchange resins

    Microsoft Academic Search

    Arne Staby; Randi Holm Jensen; Matthias Bensch; Jürgen Hubbuch; Dorte L. Dünweber; Janus Krarup; Jacob Nielsen; Mette Lund; Steffen Kidal; Thomas Budde Hansen; Inge Holm Jensen

    2007-01-01

    A comparative study on weak anion exchangers was performed to investigate the pH dependence, binding strength, particle size distribution, and static and dynamic capacity of the chromatographic resins. The resins tested included: DEAE Sepharose FF, Poros 50 D, Fractogel EMD DEAE (M), MacroPrep DEAE Support, DEAE Ceramic HyperD 20, and Toyopearl DEAE 650 M. Testing was performed with five different

  11. Comparison of chromatographic ion-exchange resins

    Microsoft Academic Search

    Arne Staby; Inge Holm Jensen

    2001-01-01

    A comparative study was performed on strong anion exchangers to investigate the pH dependence, titration curves, efficiency, binding strength, particle size distribution, and static and dynamic capacity of the chromatographic resins. The resins tested included Q Sepharose XL, UNO Q-1, Poros 50 HQ, Toyopearl QAE 550c, Separon HemaBio 1000Q, Q-Cellthru Bigbeads Plus, Q Sepharose HP and Toyopearl SuperQ 650s. Testing

  12. Comparison of chromatographic ion-exchange resins

    Microsoft Academic Search

    Arne Staby; Maj-Britt Sand; Ronni G. Hansen; Jan H. Jacobsen; Line A. Andersen; Michael Gerstenberg; Ulla K. Bruus; Inge Holm Jensen

    2005-01-01

    A comparative study was performed on heparin resins and strong and weak cation exchangers to investigate the pH dependence, efficiency, binding strength, particle size distribution, static and dynamic capacity, and scanning electron microscopy pictures of chromatographic resins. The resins tested include: Heparin Sepharose FF, SP Sepharose FF, CM Sepharose FF, Heparin Toyopearl 650m, SP Toyopearl 650m, CM Toyopearl 650m, Ceramic

  13. Modeling Uranium-Proton Ion Exchange in Biosorption

    E-print Network

    Volesky, Bohumil

    Modeling Uranium-Proton Ion Exchange in Biosorption J I N B A I Y A N G A N D B O H U M I L V O L E, Quebec, Canada H3A 2B2 Biosorption of uranium metal ions by a nonliving protonated Sargassum fluitans seaweed biomass was used to remove the heavy metal uranium from the aqueous solution. Uranium biosorption

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

    PubMed Central

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

    2001-01-01

    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

  15. 1.17972 Fractoprep Ion Exchange chromatography (IEX)

    E-print Network

    Lebendiker, Mario

    1.17972 Fractoprep® SO3 - Ion Exchange chromatography (IEX) Fractoprep® is a hydrophilic synthetic Sulfogroup (SO3)- Protein binding capacity ~ 100 mg lysozyme/ml of gel pH stability range pH 2 up to pH 14

  16. Stress relaxation in glasses strengthened by ion exchange

    Microsoft Academic Search

    L. A. Trushkova; R. L. Kelina; Yu. N. Viktorova; O. I. Pukhlik; V. A. Khvostova

    1981-01-01

    The strength of the glasses strengthened by ion exchange depends on the value of the residual compressive stresses in the surface layer, andthe depth of the diffusion layer (i. e., the zone in which the compressive stresses are effective) determines the stability of the strength properties under abrasive attack. At higher temperatures, the residual stresses may relax. Since the effect

  17. Selected Ion Exchange Applications in the Hydrometallurgical Industry

    Microsoft Academic Search

    J. van Deventer

    2011-01-01

    Ion exchange is increasingly used in hydrometallurgical applications for the recovery or purification of metal solutions or for effluent treatment. This article reviews some recent applications, including the primary recovery of gold, uranium, and rhenium, and the purification of cobalt electrolyte to ensure high-purity metal by the removal of nickel, copper, zinc, and cadmium. Improved recoveries and adherence to environmental

  18. 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...

  19. Small Column Ion Exchange Design and Safety Strategy

    Microsoft Academic Search

    T. Huff; M. Rios-Armstrong; R. Edwards; D. Herman

    2011-01-01

    Small Column Ion Exchange (SCIX) is a transformational technology originally developed by the Department of Energy (DOE) Environmental Management (EM-30) office and is now being deployed at the Savannah River Site (SRS) to significantly increase overall salt processing capacity and accelerate the Liquid Waste System life-cycle. The process combines strontium and actinide removal using Monosodium Titanate (MST), Rotary Microfiltration, and

  20. Controlled drug release from coated floating ion exchange resin beads

    Microsoft Academic Search

    F. Atyabi; H. L. Sharma; H. A. H. Mohammad; J. T. Fell

    1996-01-01

    Ion exchange resin beads can be loaded with bicarbonate and coated with a semipermeable membrane. These beads exhibit prolonged gastric residence due to release of carbon dioxide which is trapped inside the coating of the beads. In addition to the bicarbonate, a model drug, theophylline, has also been loaded onto the resin. This system gives a controlled release of drug,

  1. 21 CFR 173.20 - Ion-exchange membranes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...reaction with chloromethyl methyl ether, and by subsequent amination with tri-methyl-amine, di-methyl-amine, di-ethyl-ene-triamine, or di-methyl-ethanol-amine. (b) The ion-exchange membrane is manufactured so as to comply...

  2. Chemical degradation of an ion exchange resin processing salt solutions

    Microsoft Academic Search

    Stuart T. Arm; David L. Blanchard; Sandra K. Fiskum

    2005-01-01

    This paper describes the results from an investigation into the chemical degradation of an organic ion exchange resin, SuperLig® 644, over 25 repeated cycles separating cesium from an alkaline solution of sodium salts with subsequent elution. Battelle Pacific Northwest Division (PNWD) tested the resin with a salt solution simulating the radioactive wastes currently stored at Hanford, Washington, USA generated from

  3. Cyanide recycling using strong-base ion-exchange resins

    Microsoft Academic Search

    Versiane Albis Leão; Virgínia S. T. Ciminelli; Renato De Souza Costa

    1998-01-01

    Among the techniques available to recover cyanide and metal cyanocomplexes from diluted streams, ion-exchange resins seem attractive because of the possibility of treating either pulps or clear solutions with this process. This article discusses the results of adsorption and elution of metal cyanocomplexes obtained with industrial effluents and selected data from the literature. The behavior of iron and copper cyanocomplexes

  4. Copper Removal from A-01 Outfall by Ion Exchange

    SciTech Connect

    Oji, L.N.

    1999-02-17

    Chelex100, a commercially available ion exchange resin, has been identified in this study as having a significant affinity for copper and zinc in the A-01 outfall water. Removal of copper and zinc from A-01 outfall water will ensure that the outfall meets the state of South Carolina's limit on these heavy metals.

  5. 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...

  6. Charge-exchange born He(+) ions in the solar wind

    NASA Astrophysics Data System (ADS)

    Gruntman, Michael A.

    1992-07-01

    The effect of charge transfer between solar wind alpha-particles and hydrogen atoms of interstellar origin is revisited. Singly-charged helium ions born in the charge transfer carry important information on processes in the solar wind and the heliosphere. The velocity distribution of such He(+) ions is substantially different from that of He(+) pick-up ions due to ionization of the interstellar helium atoms. Estimates of the expected abundances of the charge-exchange born He(+) in the solar wind are presented, and the possibility of measuring this plasma component on deep space missions is discussed.

  7. Boroaluminosilicate glasses as ion exchange materials

    Microsoft Academic Search

    Jayshree Ramkumar; S. Chandramouleeswaran; V. Sudarsan; R. K. Vatsa; S. Shobha; V. K. Shrikhande; G. P. Kothiyal; T. Mukherjee

    2010-01-01

    Sodium boroaluminosilicate glasses, (Na2O)0.22(K2O)0.029(B2O3)0.05(SiO2)0.69(Al2O3)0.011 and (Na2O)0.05(K2O)0.029(B2O3)0.22(SiO2)0.69(Al2O3)0.011 having different B2O3 to Na2O mole ratio of 0.23 and 4.4 respectively were investigated for their uptake characteristics of cationic dyes, namely Rhodamine 6G and methylene blue, from aqueous solutions. Both the glasses have been found to adsorb these dyes. However, the glass with B2O3 to Na2O ratio of 0.23 is found to have

  8. Interaction of heavy metal ions with an ion exchange resin obtained from a natural polyelectrolyte

    Microsoft Academic Search

    Hernán A. Maturana; Iván M. Peri?; Bernabé L. Rivas; S. Amalia Pooley

    2011-01-01

    An ion exchange resin was synthesized by using a natural polyelectrolyte, sodium alginate, and barium ion as a cross-linker\\u000a reagent. Resin was characterized by TGA and SEM. Equilibrium and kinetic experiments of Pb2+, Hg2+, Ni2+, Co2+, Fe2+, and Fe3+ ions uptake by barium alginate beads were carried out in batch-type experiments under different values of pH. The removal\\u000a efficiency increases

  9. Ion exchange resins of high loading capacity, high chloride tolerance and rapid elution for uranium recovery

    Microsoft Academic Search

    Yan

    1982-01-01

    Ion exchange process for the recovery of uranium from a pregnant carbonate lixiviant employed in uranium leaching operations in which the lixiviant is passed over a precipitation inducing anionic ion exchange resin under conditions to load the resin predominantly with non-exchangeable uranium. Non-exchangeable uranium is then recovered from the resin by eluting the resin with an aqueous acid solution having

  10. 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...

  11. Universal theoretical moment expressions for elution and frontal chromatography of pellicular ion exchange resins

    Microsoft Academic Search

    Yang Gengliang; Hu Zhide

    1996-01-01

    In this paper, theoretical moment expressions for elution and frontal chromatographies are derived when the packing material in a column is pellicular ion exchange resin. From the retention time and the height equivalent to a theoretical plate (HEPT) obtained, the advantages of the pellicular ion exchange resin are discussed by comparing with the conventional ion exchange resin bead.

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

    USGS Publications Warehouse

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

    2004-01-01

    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.

  13. Radiation degradation in EPICOR-2 ion exchange resins

    SciTech Connect

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

    1990-09-01

    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 by EG G Idaho, Inc. at the Idaho Engineering Laboratory. This is the final report of this task and summarizes results and analyses of three samplings of ion exchange resins from prefilters PF-8 and -20. Results are compared with baseline data from tests performed on unirradiated resins supplied by Epicor, Inc. to determine the extent of degradation due to the high internal radiation dose received by the organic resins. Results also are compared with those of other researchers. 18 refs., 23 figs., 7 tabs.

  14. Hybrid metallic ion-exchanged waveguides for SPR biological sensing

    NASA Astrophysics Data System (ADS)

    de Bonnault, S.; Bucci, D.; Zermatten, P.. J.; Charette, P. G.; Broquin, J. E.

    2015-02-01

    Glass substrates have been used for decades to create biosensors due to their biocompatibility, low thermal conductivity, and limited fluorescence. Among the different types of sensors, those based on surface plasmon resonance (SPR) allow exploitation of the sensing lightwave at the vicinity of the sensor surface where small entities such as DNA or proteins are located. In this paper, ion-exchanged waveguides and SPR are combined to create a multianalyte optical sensor integrated onto glass. First the principle of operation is introduced, then the theoretical analysis and design of the sensing element. Simulations have been carried out using the Aperiodic Fourier Modal Method (AFMM) and a custom software that handles ion-exchange index-profiles. Fabrication and characterization processes are also presented. Finally the first experimental spectra are displayed and discussed. The sensor presents a bulk sensibility of 5000nm/RIU.

  15. Development of inorganic ion exchangers for nuclear waste remediation. 1998 annual progress report

    SciTech Connect

    Clearfield, A.; Egan, B.Z.; Bortun, A.I.; Bortun, L.N.; Khainakov, S.; Sylvester, P.

    1998-06-01

    'To expand the authors efforts to provide families of inorganic ion exchangers useful on a global scale. In carrying out this objective, they will synthesize a variety of ion exchange materials, determine their structures and where necessary alter these structures to build in the desired properties. The underlying thermodynamic, kinetic and molecular basis of ion exchange behavior will be elucidated and their suitability for nuclear waste remediation will be assessed. As of September 1, 1996, they have synthesized a number of highly selective inorganic ion exchangers, determined their crystal structures and elucidated the mechanism of exchange for a number of these exchangers.'

  16. CHROMATOGRAPHIC MEASUREMENTS OF LITHIUM ISOTOPE SEPARATION BY ION EXCHANGE

    Microsoft Academic Search

    Knyazev

    1963-01-01

    ABS>A chromatographic method was used for measuring coefficients for Li\\/; sup 6\\/ and Li⁷ separation for three ion exchange systems: sulfocation KU-2 ; (10i divinyl benzene) 1) in mixed H-- Li form-- LiCl + HCl aqueous solution with ; total concentration 0.05 N; 2) identical system with sulfocations SBS; and, 3) ; mixed Li--NH form-- LiCl + NHâCl solution with

  17. Ion Exchange for Product Recovery in Lactic Acid Fermentation

    Microsoft Academic Search

    Shailesh M. Dave; Sachin S. Patil; A. K. Suresh

    1997-01-01

    Lactic acid fermentation is a product-inhibited fermentation, and product recovery costs in downstream processing are considerable. In this paper the feasibility of ion exchange as a technique for product separation is investigated. In initial experiments an indigenously manufactured weak-base resin was found to show promise, and detailed equilibrium and kinetic data required for design and scale-up of the separation process

  18. Cyanide regeneration by AVR process using ion exchange polymeric resins

    Microsoft Academic Search

    A. L Silva; R. A Costa; A. H Martins

    2003-01-01

    This work presents laboratory bench scale results for cyanide regeneration from pure alkaline aqueous solutions of gold, copper and iron cyanocomplexes using an innovative option of the AVR process associated to the ion exchange polymeric resins Imac HP555s® ((Room&Haas––USA) and Amberlite IRA-420® (Room&Haas Brasil Ltda.) in columns. The resin Imac HP555s® adsorbed 64.5% CN from the alkaline solution containing metal

  19. Cyanide recycling using strong-base ion-exchange resins

    Microsoft Academic Search

    Versiane Albis Leão; Virgínia S. T. Ciminelli; Renato de Souza Costa

    1998-01-01

    Among the techniques available to recover cyanide and metal cyanocomplexes from diluted streams, ion-exchange resins seem\\u000a attractive because of the possibility of treating either pulps or clear solutions with this process. This article discusses\\u000a the results of adsorption and elution of metal cyanocomplexes obtained with industrial effluents and selected data from the\\u000a literature. The behavior of iron and copper cyanocomplexes

  20. Elution of ion exchange resins by use of ultrasonication

    Microsoft Academic Search

    D Feng; C Aldrich

    2000-01-01

    The feasibility of using ultrasound to enhance the elution of three ion exchange resins was investigated. A laboratory-scale elution column immersed in an ultrasonic bath was used to investigate three elution systems. XAD7–Au (eluted with NaOH, at a pH of 10), IR120H–Cd (eluted with HCl) and A375–SO42? (eluted with saturated lime solutions). The physico-chemical stability of the resins was not

  1. Leach method including means to protect ion exchange resin

    Microsoft Academic Search

    R. L. Lozano; T. Yan

    1981-01-01

    A method for recovering uranium and\\/or related values which include means for protecting ion-exchange resins in the recovery operation from oxidative degradation due to contact with hydrogen peroxide. A guard chamber is positioned in the elution circuit so that barren eluant, after it is stripped of its uranium and\\/or related values by treatment with hydrogen peroxide, will flow through the

  2. CHARACTERIZATION OF CYCLED SPHERICAL RESORCINOL-FORMALDEHYDE ION EXCHANGE RESIN

    Microsoft Academic Search

    C. Nash; M. Duignan

    2010-01-01

    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 11 mL beds in

  3. Novel ion-exchange spacer for improving electrodialysis II. Coated spacer

    Microsoft Academic Search

    R. Messalem; Y. Mirsky; N. Daltrophe; G. Saveliev; O. Kedem

    1998-01-01

    Ion-conducting spacers were prepared by applying an ion-exchange coating to commercially available polypropylene netting. Homogeneous and heterogeneous types of coating were used. Homogeneous anion-exchange coating consisted of bromomethylated and aminated polysulfone, homogeneous cation-exchange coating of sulfonated polysulfone. All heterogeneous coatings consisted of ground ion-exchange resin, embedded in crosslinked poly(vinyl alcohol). All the coated spacers increased the rate of desalting of

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

    PubMed

    Rey, M A

    2001-06-22

    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

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    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.

  6. Lithium Isotope Fractionations on Inorganic Ion-Exchangers with Different Ion-Sieve Properties

    Microsoft Academic Search

    Kenta Ooi; Qi Feng; Hirofumi Kanoh; Takahiro Hirotsu; Takao Oi

    1995-01-01

    Lithium isotope fractionation properties were studied on five kinds of inorganic ion exchangers with different ion-sieve properties. The lithium isotope separation factors were determined batchwise in a LiOH or (LiCl + LiOH) solution at 25 or 20°C, respectively. The separation factor increased in the order birnessite-type manganese oxide ? hollandite-type manganese oxide ? spinel-type manganese oxides ? cubic antimonic acid

  7. Structural Insight into the Ion-Exchange Mechanism of the Sodium/Calcium Exchanger

    SciTech Connect

    Liao, Jun; Li, Hua; Zeng, Weizhong; Sauer, David B.; Belmares, Ricardo; Jiang, Youxing (UTSMC)

    2012-06-19

    Sodium/calcium (Na{sup +}/Ca{sup 2+}) exchangers (NCX) are membrane transporters that play an essential role in maintaining the homeostasis of cytosolic Ca{sup 2+} for cell signaling. We demonstrated the Na{sup +}/Ca{sup 2+}-exchange function of an NCX from Methanococcus jannaschii (NCX{_}Mj) and report its 1.9 angstrom crystal structure in an outward-facing conformation. Containing 10 transmembrane helices, the two halves of NCX{_}Mj share a similar structure with opposite orientation. Four ion-binding sites cluster at the center of the protein: one specific for Ca{sup 2+} and three that likely bind Na{sup +}. Two passageways allow for Na{sup +} and Ca{sup 2+} access to the central ion-binding sites from the extracellular side. Based on the symmetry of NCX{_}Mj and its ability to catalyze bidirectional ion-exchange reactions, we propose a structure model for the inward-facing NCX{_}Mj.

  8. Continuous ion exchange separation of zirconium and hafnium

    SciTech Connect

    Begovich, J.M.; Sisson, W.G.

    1981-01-01

    A pressurized continuous annular chromatograph (CAC) has been developed for truly continuous ion exchange preparative separations. This device utilizes a slowly rotating annular bed of sorbent material, fixed multiple feed points, and fixed withdrawal locations. Most of our investigations have been performed with a 28-cm-diam by 60-cm-long CAC, but a larger model has recently been designed and constructed. A detailed study has been made of the separation of copper, nickel, and cobalt components from a simulated carbonate leach liquor of the Caron process for recovering nickel and cobalt from laterite ores. Recent studies have investigated the ion exchange separation of zirconium and hafnium from a sulfate feed solution. Nuclear reactor-grade zirconium, containing < 0.01 wt % hafnium, and hafnium, containing < 1% zirconium, have been continuously prepared using cation exchange resin in the pressurized CAC. This device, because of its continuous feed and product withdrawal, its adaptability to largescale operations, and its ability to separate many components, is expected to make chromatography a more competitive process in the industrial sector.

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

    Microsoft Academic Search

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

    1985-01-01

    The authors investigate equilibrium of uranium ion exchange in hydrofluoric acid and ammonium fluoride solutions. They show that HF and NHâF 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.

  10. Diffusional transport of ions in plasticized anion-exchange membranes.

    PubMed

    Kumar, Rakesh; Pandey, Ashok K; Sharma, Manoj K; Panicker, L V; Sodaye, Suparna; Suresh, G; Ramagiri, Shobha V; Bellare, Jayesh R; Goswami, A

    2011-05-19

    Diffusional transport properties of hydrophobic anion-exchange membranes were studied using the polymer inclusion membrane (PIM). This class of membranes is extensively used in the chemical sensor and membrane based separation processes. The samples of PIM were prepared by physical containment of the trioctylmethylammonium chloride (Aliquat-336) in the plasticized matrix of cellulose triacetate (CTA). The plasticizers 2-nitrophenyl octyl ether, dioctyl phthalate, and tris(2-ethylhexyl)phosphate having different dielectric constant and viscosity were used to vary local environment of the membrane matrix. The morphological structure of the PIM was obtained by atomic force microscopy and transmission electron microscopy (TEM). For TEM, platinum nanoparticles (Pt nps) were formed in the PIM sample. The formation of Pt nps involved in situ reduction of PtCl(6)(2-) ions with BH(4)(-) ions in the membrane matrix. Since both the species are anions, Pt nps thus formed can provide information on spatial distribution of anion-exchanging molecules (Aliquat-336) in the membrane. The glass transitions in the membrane samples were measured to study the effects of plasticizer on physical structure of the membrane. The self-diffusion coefficients (D) of the I(-) ions and water in these membranes were obtained by analyzing the experimentally measured exchange rate profiles of (131)I(-) with (nat)I(-) and tritiated water with H(2)O, respectively, between the membrane and equilibrating solution using an analytical solution of Fick's second law. The values of D(I(-)) in membrane samples with a fixed proportion of CTA, plasticizer, and Aliquat-336 were found to vary significantly depending upon the nature of the plasticizer used. The comparison of values of D with properties of the plasticizers indicated that both dielectric constant and viscosity of the plasticizer affect the self-diffusion mobility of I(-) ions in the membrane. The value of D(I(-)) in the PIM samples did not vary significantly with concentration of Aliquat-336 up to 0.5 mequiv g(-1), and thereafter D(I(-)) increased linearly with Aliquat-336 concentration in the membrane. The self-diffusion coefficients of water D(H(2)O) in PIM samples were found to be 1 order of magnitude higher than the value of D(I(-)) and varied slightly depending upon the plasticizer present in the membrane. It was observed in electrochemical impedance spectroscopic studies of the PIM samples that diffusion mobility of NO(3)(-) ions was 1.66 times higher than that of I(-) ions, and diffusion mobility of SO(4)(2-) ions was half of that for I(-) ions. The theoretical interpretation of experimental counterions exchange rate profiles in terms of the Nernst-Planck equation for interdiffusion also showed higher diffusion mobility of NO(3)(-) ions in the PIM than Cl(-), I(-), and ClO(4)(-) ions, which have comparable diffusion mobility. PMID:21513289

  11. Single and binary adsorption of proteins on ion-exchange adsorbent: The effectiveness of isothermal models.

    PubMed

    Liang, Juan; Fieg, Georg; Shi, Qing-Hong; Sun, Yan

    2012-09-01

    Simultaneous and sequential adsorption equilibria of single and binary adsorption of bovine serum albumin and bovine hemoglobin on Q Sepharose FF were investigated in different buffer constituents and initial conditions. The results in simultaneous adsorption showed that both proteins underwent competitive adsorption onto the adsorbent following greatly by protein-surface interaction. Preferentially adsorbed albumin complied with the universal rule of ion-exchange adsorption whereas buffer had no marked influence on hemoglobin adsorption. Moreover, an increase in initial ratios of proteins was benefit to a growth of adsorption density. In sequential adsorption, hemoglobin had the same adsorption densities as single-component adsorption. It was attributed to the displacement of preadsorbed albumin and multiple layer adsorption of hemoglobin. Three isothermal models (i.e. extended Langmuir, steric mass-action, and statistical thermodynamic (ST) models) were introduced to describe the ion-exchange adsorption of albumin and hemoglobin mixtures. The results suggested that extended Langmuir model gave the lowest deviation in describing preferential adsorption of albumin at a given salt concentration while steric mass-action model could very well describe the salt effect in albumin adsorption. For weaker adsorbed hemoglobin, ST model was the preferred choice. In concert with breakthrough data, the research further revealed the complexity in ion-exchange adsorption of proteins. PMID:22888059

  12. Ion exchange and adsorption on low rank coals for liquefaction

    SciTech Connect

    Vorres, K.S.

    1994-09-01

    The objectives of this program are to study the application of catalysts and the catalysis of liquefaction of low rank coals. Ion exchange and adsorption techniques are being used or modified to incorporate catalytically active metals (Fe, Co, Ni and Mo) in relatively small (100-2000 ppM) quantities into coal samples. Relative oil yields are being determined by PETC and Auburn University workers as collaborators to establish the effectiveness of the catalyst incorporation techniques. It is hoped that these techniques will provide highly active forms of the catalyst in low concentrations to minimize the need for metals recovery. A two step preparation of the coal is used to (1) remove material which both limits oil conversion and prepares for the addition of exchangeable catalyst, and (2) add catalytically active material which enhances the conversion of the coal matter to the oil fraction in the processing.

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

    PubMed

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

    2000-01-01

    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

  14. Ion Exchange Testing with SRF Resin FY2012

    SciTech Connect

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

    2013-06-11

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

  15. Ion Exchange Testing with SRF Resin FY 2012

    SciTech Connect

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

    2014-07-02

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

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

    PubMed Central

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

    2013-01-01

    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

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

    E-print Network

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

    2014-01-01

    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.

  18. Solid Phase Luminescence of Several Rare Earth Ions on Ion-Exchange Films

    NASA Technical Reports Server (NTRS)

    Tanner, Stephen P.; Street, Kenneth W., Jr.

    1999-01-01

    The development and characterization of a novel ion-exchange film for solid-phase fluorometry and phosphorimetry is reported. This new cation-exchange material is suitable for spectroscopic applications in the ultraviolet and visible regions. It is advantageous because it, as a single entity, is easily recovered from solution and mounted in the spectrofluorometers. After preconcentration on the film, the luminescence intensity of lanthanide ions is several orders of magnitude greater than that of the corresponding solution, depending on the volume of solution and the amount of film. This procedure allows emission spectral measurements and determination of lanthanide ions at solution concentrations of < 5 (micro)g/L. The film may be stored for subsequent reuse or as a permanent record of the analysis. The major drawback to the use of the film is slow uptake of analyte due to diffusion limitations.

  19. A study of hard:soft layer ratios and angular switching in exchange coupled media

    Microsoft Academic Search

    A. Baker; M. Billard; K. Brown; A. Goadsby; S. Green; C. Howard; S. Kodippili; A. Newton; X. Ning; M. Stead; L. Vallance; L. Zang; D. A. Allwood; M. T. Bryan; J. Dean

    2009-01-01

    We have performed micromagnetic simulations to investigate the magnetic behavior of exchange spring grains for hard disk recording applications. The thickness ratio between magnetically hard and soft layers was varied while the soft layer anisotropy was altered to maintain a suitable energy barrier between opposite magnetization states. The minimum required magnetic field for switching a grain and the corresponding field

  20. Separation of ammonia from wastewater using clinoptilolite as ion exchanger

    SciTech Connect

    Czaran, E.; Meszaros-Kis, A.; Domokos, E.; Papp, J.

    1988-01-01

    The cation exchange properties of a Hungarian clinoptilolite rock from the Tokaj mountains have been studied. The aim of this work has been to prepare suitable cation containing forms for NH/sub 4//sup +/-removal and regeneration of the NH/sub 4//sup +/-form. The process has been followed from the start with static laboratory experiments through laboratory dynamic measurements up to pilot plant. The static CEC of the clinoptilolite containing rock proved to be 1.2 meq/q. However, under dynamic conditions this value is only 0.2 - 0.3 depending on the circumstances, thus this material is capable of the elimination of 3 - 5 mg NH/sub 3/ per g rock. The exhausted clinoptilolite can be regenerated more efficiently by potassium ions than by the usually applied sodium ions.

  1. Extraction and ion-exchange behavior of mendelevium (II)

    SciTech Connect

    Guseva, L.I.; Tikhomirova, G.S.; Buklanov, G.V.; Pkhar, Z.Z.; Lebedev, I.A.; Katargin, N.V.; Myasoedov, B.F.

    1988-09-01

    Medelevium-256 was obtained via multinucleon transfer reactions upon irradiation of /sup 249/Bk by /sup 22/Ne ions from the extracted beam of a U-300 cyclotron. In order to extract mendelevium and separate it from the products of nuclear reactions, an express ion-exchange method using one column with cationite and zinc amalgam in a solution of 1 mole/liter HCl as the eluent was developed. It was shown that under these conditions mendelevium is reduced and washes out as an alkaline earth element. On the basis of the location of the peaks of the elution curves of Sr/sup 2+/, Eu/sup 2+/, and Md/sup 2+/, the value of the ionic radium of Md/sup 2+/ is estimated and is used to estimate the heat of hydration.

  2. Electrically switched cesium ion exchange. FY 1996 annual report

    SciTech Connect

    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

    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.

  3. Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

    Microsoft Academic Search

    M. Stejner; S. K. Nielsen; H. Bindslev; S. B. Korsholm; M. Salewski

    2011-01-01

    For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio---i.e. the tritium to deuterium density ratio. Measurements of the fuel ion ratio will be important for plasma control and machine protection in future experiments

  4. Low-level liquid waste decontamination by ion exchange

    SciTech Connect

    Campbell, D.O.; Lee, D.D.; Dillow, T.A.

    1991-12-01

    Improved processes are being developed to treat contaminated liquid wastes that have been and continue to be generated at Oak Ridge National Laboratory. Both inorganic and organic ion-exchange methods have given promising results. Nickel and cobalt hexacyanoferrate(2) compounds are extremely selective for cesium removal, with distribution coefficients in excess of 10{sup 6} and remarkable insensitivity to competition from sodium and potassium. They tend to lose effectiveness at pH > {approximately}11, but some formulations are useful for limited periods of time up to pH {approximately}13. Sodium titanate is selective for strontium removal at high pH. The separations are so efficient that simple batch processes can yield large decontamination factors while generating small volumes of solid waste. A resorcinol-based resin developed at the Savannah River Site gave superior cesium removal, compared with other organic ion exchangers; the distribution coefficient was limited primarily by competition from potassium and was nearly independent of sodium. The optimum pH was {approximately}12.5. It was much less effective for strontium removal, which was limited by competition from sodium. 8 refs., 6 figs., 9 tabs.

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

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    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.

  6. Optical absorption of copper nanocluster composite soda-lime glass synthesized by binary ion-exchange and ion irradiation

    Microsoft Academic Search

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

    2004-01-01

    Nanometer dimension copper clusters are introduced into the soda-lime glass matrix by ion-exchange method. The exchanged glasses show an increase in index of refraction thus forming themselves optical waveguides. Optical absorption spectroscopic analysis showed signature of copper clusters in the ion-exchanged glass. Theoretical optical absorption spectrum was calculated using the Mie's theory, and it is confirmed that copper clusters of

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

    SciTech Connect

    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

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

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

    SciTech Connect

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

    1995-03-01

    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.

  10. Metal-organic framework threaded with aminated polymer formed in situ for fast and reversible ion exchange.

    PubMed

    Gao, Liang; Li, Chi-Ying Vanessa; Chan, Kwong-Yu; Chen, Zhe-Ning

    2014-05-21

    A porous metal-organic framework composite with flexible anion-exchange polymers threaded within the host cavity demonstrates very fast and reversible ion-exchange activity. Polyvinyl benzyl trimethylammonium hydroxide (PVBTAH) caged in ZIF-8 is synthesized in steps of chloro-monomer impregnation, in situ polymerization, amination, and alkaline ion exchange. The synthesized non-cross-linked PVBTAH?ZIF-8 material exhibits superior ion-exchange kinetics compared to conventional ion-exchange resins. PMID:24802277

  11. Small Column Ion Exchange Design and Safety Strategy

    SciTech Connect

    Huff, T.; Rios-Armstrong, M.; Edwards, R.; Herman, D.

    2011-02-07

    Small Column Ion Exchange (SCIX) is a transformational technology originally developed by the Department of Energy (DOE) Environmental Management (EM-30) office and is now being deployed at the Savannah River Site (SRS) to significantly increase overall salt processing capacity and accelerate the Liquid Waste System life-cycle. The process combines strontium and actinide removal using Monosodium Titanate (MST), Rotary Microfiltration, and cesium removal using Crystalline Silicotitanate (CST, specifically UOP IONSIV{reg_sign}IE-911 ion exchanger) to create a low level waste stream to be disposed in grout and a high level waste stream to be vitrified. The process also includes preparation of the streams for disposal, e.g., grinding of the loaded CST material. These waste processing components are technically mature and flowsheet integration studies are being performed including glass formulations studies, application specific thermal modeling, and mixing studies. The deployment program includes design and fabrication of the Rotary Microfilter (RMF) assembly, ion-exchange columns (IXCs), and grinder module, utilizing an integrated system safety design approach. The design concept is to install the process inside an existing waste tank, Tank 41H. The process consists of a feed pump with a set of four RMFs, two IXCs, a media grinder, three Submersible Mixer Pumps (SMPs), and all supporting infrastructure including media receipt and preparation facilities. The design addresses MST mixing to achieve the required strontium and actinide removal and to prevent future retrieval problems. CST achieves very high cesium loadings (up to 1,100 curies per gallon (Ci/gal) bed volume). The design addresses the hazards associated with this material including heat management (in column and in-tank), as detailed in the thermal modeling. The CST must be size reduced for compatibility with downstream processes. The design addresses material transport into and out of the grinder and includes provisions for equipment maintenance including remote handling. The design includes a robust set of nuclear safety controls compliant with DOE Standard (STD)-1189, Integration of Safety into the Design Process. The controls cover explosions, spills, boiling, aerosolization, and criticality. Natural Phenomena Hazards (NPH) including seismic event, tornado/high wind, and wildland fire are considered. In addition, the SCIX process equipment was evaluated for impact to existing facility safety equipment including the waste tank itself. SCIX is an innovative program which leverages DOE's technology development capabilities to provide a basis for a successful field deployment.

  12. Principles of fuel ion ratio measurements in fusion plasmas by collective Thomson scattering

    NASA Astrophysics Data System (ADS)

    Stejner, M.; Nielsen, S. K.; Bindslev, H.; Korsholm, S. B.; Salewski, M.

    2011-06-01

    For certain scattering geometries collective Thomson scattering (CTS) measurements are sensitive to the composition of magnetically confined fusion plasmas. CTS therefore holds the potential to become a new diagnostic for measurements of the fuel ion ratio—i.e. the tritium to deuterium density ratio. Measurements of the fuel ion ratio will be important for plasma control and machine protection in future experiments with burning fusion plasmas. Here we examine the theoretical basis for fuel ion ratio measurements by CTS. We show that the sensitivity to plasma composition is enhanced by the signatures of ion cyclotron motion and ion Bernstein waves which appear for scattering geometries with resolved wave vectors near perpendicular to the magnetic field. We investigate the origin and properties of these features in CTS spectra and give estimates of their relative importance for fuel ion ratio measurements.

  13. STUDY OF INDUSTRIAL ION EXCHANGE SEPARATION OF RARE EARTH ELEMENTS BY EDTA COPPER METHOD. VII. MODELS OF INDUSTRIAL ION EXCHANGE TOWERS

    Microsoft Academic Search

    Nishigori

    1961-01-01

    Two new models of ion exchange towers were constructed: one hopper type, ; the other cylinder type\\/su Results of tests on the scale models indicate they can ; be scaled-up for industrial processes. (P.C.H.);

  14. Ion exchange selectivities of calcium alginate gels for heavy metals.

    PubMed

    Jodra, Y; Mijangos, F

    2001-01-01

    An equilibrium model has been proposed and verified, based on the conditions in the gel phase and Donnan equilibrium theory, for the analysis of the experimental data on the recovery of lead, copper, cadmium, cobalt, nickel and zinc from synthetic, nonmetallic aqueous solutions on calcium alginate gels. This equilibrium model considers that the system behaves as an ion-exchange process between the calcium in the gels and the divalent metals in solution, and that the metallic portion enclosed in gel fluid is supposed an important quantitative contribution to the total amount of metal uptake by gels. According to the equilibrium constants calculated, it is deduced that the selectivity order is: Pb > Cu > Cd > Ni > Zn > Co. PMID:11380185

  15. Coherent pion production in heavy ion charge exchange reactions

    NASA Astrophysics Data System (ADS)

    Boyard, J.-L.; Augustyniak, W.; Dahl, R.; Drews, M.; Ellegaard, C.; Farhi, L.; Gaarde, C.; Hennino, T.; Jensen, J. A.; Jourdain, J.-C.; Kagarlis, M.; Kunne, R.; Larsen, J. S.; Radvanyi, P.; Ramstein, B.; Roy-Stephan, M.; Zupranski, P.

    2005-06-01

    We report the first observation of coherent pion production induced by a heavy ion charge exchange reaction. The ( 12C, 12N) reaction [D. Bachelier et al., Phys. Lett. B 172 (1986) 23; M. Roy-Stephan et al., Nucl. Phys. A 488 (1988) 178] at 1.1 GeV/nucleon has been used to shine negative (off-shell) pions on nuclei and observe (on-shell) pions, leaving the target nucleus in its ground state. The experiment was performed at the Laboratoire National Saturne with the SPES4- ? setup [Laurent Farhi PHD thesis IPNO-T97-12, Universite d'Orsay, 1997; Rasmus Dahl Ph.D., Niels Bohr Institutet, Copenhagen (1999)].

  16. Copper ion-exchanged channel waveguides optimization for optical trapping.

    PubMed

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

    2013-08-01

    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

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    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.

  18. D/H ratios and hydrogen exchangeability of type-II kerogens with increasing thermal maturity

    USGS Publications Warehouse

    Lis, G.P.; Schimmelmann, A.; Mastalerz, Maria

    2006-01-01

    Stable isotope ratios of non-exchangeable hydrogen (??Dn) and of carbon were measured in type-II kerogens from two suites of Late Devonian to Early Mississippian black shale, one from the New Albany Shale (Illinois Basin) and the other from the Exshaw Formation (Alberta Basin). The largely marine-derived organic matter had similar original stable isotope ratios, but today the suites of kerogens express gradients in thermal maturity that have altered their chemical and isotopic compositions. In both suites, ??D n values increase with maturation up to a vitrinite reflectance of Ro 1.5%, then level out. Increasing ??Dn values suggest isotopic exchange of organic hydrogen with water-derived deuterium and/or preferential loss of 1H-enriched chemical moieties from kerogen during maturation. The resulting changes in ??Dn values are altering the original hydrogen isotopic paleoenvironmental signal in kerogen, albeit in a systematic fashion. The specific D/H response of each kerogen suite through maturation correlates with H/C elemental ratio and can therefore be corrected to yield paleoenvironmentally relevant information for a calibrated system. With increasing thermal maturity, the abundance of hydrogen in the kerogen that is isotopically exchangeable with water hydrogen (expressed as Hex, in % of total hydrogen) first decreases to reach a minimum at Ro ??? 0.8-1.1%, followed by a substantial increase at higher thermal maturity. ?? 2005 Elsevier Ltd. All rights reserved.

  19. Ion exchange upgrade boosts Gainesville's makeup water system performance

    SciTech Connect

    Brew, C. (Gainesville Regional Utilities, FL (United States)); Fletcher, C.

    1994-10-01

    This article reports that the choice for upgrading its system produces high quality water, economically, with a minimum of operator attention at the Kelly power plant. New water treatment equipment was commissioned at Kelly Generating Station in 1993 and took over the load from an existing conventional ion exchange water treatment system. The old equipment, installed in the early 1960s, included a two bed (strong acid cation exchanger/strong base anion exchanger) primary system followed by a mixed bed polisher. Two trains allowed continuous water production during regenerations. The old system was designed to treat relatively low total dissolved solids (TDS) water from a local spring. In the mid 1970s, the Kelly plant changed to its current water source, Gainesville city water. This water is drawn from the Florida aquifer and is lime softened. The TDS of the new water source is about twice the previous level so the capacity of the old water treatment equipment reduced by about half. When water consumption was high, a train would required regeneration every 36 to 48 hours. Though the regeneration sequence was semi-automated, an operator was needed full time during the three to four hours that it took to complete a regeneration. The nature of the Kelly plant's operation meant that the plant cycled up and down frequently, and the old water treatment system had difficulty coping with the erratic water demand. The age of the existing water treatment equipment and the amount of operator attention it required prompted Gainesville Regional Utilities (GRU) to search for new water treatment equipment.

  20. Magnesium adsorption and ion exchange in marine sediments: A multi-component model

    NASA Astrophysics Data System (ADS)

    von Breymann, Marta T.; Collier, Robert; Suess, Erwin

    1990-12-01

    The observed distribution of dissolved magnesium in the pore water of rapidly accumulating sediments shows significant deviations from the seawater value. We have shown that deviations during early diagenesis can be explained by reactions occurring at the surface of sediment particles. In anoxic pore water environments with high levels of dissolved total carbon dioxide the formation of Mg +2·CO 3-2 complexes significantly reduces the concentration of the free Mg +2 ion. This decrease in the Mg +2 activity results in desorption of magnesium from the solid surfaces due to the re-equilibration of the adsorbed Mg +2 with the dissolved species. The effect of increasing carbonate complexation of Mg +2 in anoxic environments is initially compensated by the loss of sulfate, which is also a strong Mg +2 ligand. Therefore, significant changes in free Mg +2 concentration and thus in the magnesium desorption from solid surfaces by ligand competition for Mg +2 are more pronounced in sulfate-depleted systems undergoing methanogenesis. Such conditions are characteristic of most continental margin sediments. Another consequence of the decomposition of organic matter in hemipelagic sediments is the accumulation of high levels of ammonium ions which also displace Mg +2 from sediment-particle surfaces by ion exchange. These equilibria in the pore water-sediment systems can be described by empirical parameters, which were experimentally obtained. A computer model was used to determine the equilibrium conditions for solid-solution reactions as a function of changes in the pore-water composition in organicrich hemipelagic environments. This model includes complex formation, competition for Mg +2 between dissolved ligands and exchange sites and Mg +2/NH +4 exchange reactions. The relative proportion of desorbed and displaced Mg +2 from the solid surface depends on the characteristics of the sediment and on the ?CO 2:NH +4 regenerative ratio in the pore waters. In sediments from Bransfield Strait, the Gulf of California, and the Peru margin, both release mechanisms for Mg +2 - ligand competition and ion exchange with ammonium - were evaluated as part of the complex reaction system in order to explain the observed maxima in the dissolved magnesium profiles. Overlying the Mg +2 maxima, the Bransfield Strait and Gulf of California pore waters show minima in the dissolved magnesium concentration, concurrent with a measured increase in the cation exchange capacity (CEC) of the sediments. By including the observed CEC changes in the multi-component model we show that the negative anomaly in the dissolved Mg +2 profiles is a consequence of changes in the CEC of sediments during the very early stages of anoxic diagenesis.

  1. Microstructural studies of glass-metal composites produced by ion-exchange and hydrogen treatments

    Microsoft Academic Search

    D. Chakravorty; A. Shuttleworth; P. H. Gaskell

    1975-01-01

    Detailed electron micrographic studies have been carried out on float glass surface subjected to sodium ? copper ion-exchange in molten salts followed by a reduction treatment in hydrogen. Spherical copper particles of diameters ranging from 50 to 300 å are formed in the glass matrix depending on the ion-exchange and reduction temperatures. The nucleus density of these particles is maximum

  2. Possibility of improvement of boiler water treatment process—ion exchange vs. reverse osmosis

    Microsoft Academic Search

    Dragana V. Kuki?; Marina B. Š?iban; Branka B. Mitrovi?; Jelena M. Prodanovi?; Vesna M. Vasi?; Darjana Ž. Iveti?; Mirjana G. Antov

    2012-01-01

    The boiler water in certain power plant is produced by chemical decarbonization, sand filtration, and ion exchange. Process ends with mixed bed ion exchange. The current boiler water treatment process is analyzed in terms of achieved water quality, quantity and quality of wastewater, and amount of chemicals needed. The main disadvantage of current process is consumption of large amount of

  3. DETERMINATION OF THE EFFICIENCY OF AN ION EXCHANGE SYSTEM IN SEPARATING THE LITHIUM ISOTOPES (PRELIMINARY STUDY)

    Microsoft Academic Search

    R. E. Blanco; A. H. Kibbey; J. T. Roberts

    1954-01-01

    The lithium isotopic separation factors for the ion exchange systems ; studied appear to be quite low, of the magnitude of 1.003. Any possible effects ; on the separation factor attributable to concentration or the presence of ; complexing agents were within the limits of experimental error. The HTU for ; lithium ion exchange is low, i.e., a fraction of

  4. Evolution of ion-exchange: from Moses to the Manhattan Project to Modern Times

    Microsoft Academic Search

    Charles A. Lucy

    2003-01-01

    This article explores the history of ion-exchange from records of desalination in the Old Testament and the writings of Aristotle, to the identification of the phenomenon of ion-exchange by two English agricultural chemists, to the invention of suppressed conductivity by Small et al. [Anal. Chem. 54 (1975) 462]. It then focuses on the characteristics of the gradual and continuous evolution

  5. 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...

  6. Modeling of Crystalline Silicotitanate Ion Exchange Columns Using Experimental Data from SRS Simulated Waste

    SciTech Connect

    Walker, D.D.

    1999-03-15

    Non-elutable ion exchange using crystalline silicotitanate is being considered for removing cesium from Savannah River Site radioactive waste. The construction cost of this process depends strongly on the size of the ion exchange column required to meet product specifications.

  7. Ion Exchange Protein purification products All you need for rapid protein purification in one convenient kit

    E-print Network

    Lebendiker, Mario

    Vivapure Ion Exchange Protein purification products #12;2 All you need for rapid protein purification in one convenient kit Vivapure IEX protein purification kits employ an innovative and powerful ion exchange membrane technology for purification of proteins. Vivapure IEX purification protocols allow

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

    SciTech Connect

    NONE

    1996-01-01

    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 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

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

    SciTech Connect

    Not Available

    1993-12-01

    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.)

  10. Process for the elution of ion exchange resins in uranium recovery

    Microsoft Academic Search

    Yan

    1981-01-01

    Process for the recovery of uranium from a pregnant lixiviant employed in uranium leaching operations in which the uranium is concentrated by ion exchange resin. The ion exchange resin is eluted with an eluant containing 0.05-0.5 molar ammonium carbonate. The eluant also contains a base such as ammonium hydroxide in an amount sufficient to increase the ph to a value

  11. High speed ion exchange techniques for neptunium, plutonium, and uranium impurity assays

    SciTech Connect

    Maxwell, III, S L

    1988-01-01

    Rapid, efficient ion exchange separations can be performed 10 to 15 times faster than conventional flow rates by using a modified commercial vacuum extraction system and small particle resins. At the Savannah River Plant (SRP), these techniques are being applied to make ion exchange separation techniques more rapid and thus more practical for routine laboratory applications.

  12. In situ perchlorate determination on Purolite A850 ion exchange resin via Raman spectroscopy

    Microsoft Academic Search

    Tatiana G. Levitskaia; Sergei I. Sinkov; Samuel A. Bryan

    2007-01-01

    The reported investigation represents a first step toward development of a sensor methodology for in situ determination of ionic species retained on ion exchange column. Raman spectroscopy was demonstrated as a detection method for the determination of perchlorate loading on a non-selective ion exchange resin, Purolite A850 acrylic gel. This method has been established using laboratory water (DIW) samples and

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

    SciTech Connect

    NONE

    1995-01-01

    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.)

  14. Small-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241AN102

    Microsoft Academic Search

    Hassan

    2000-01-01

    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 and high activity waste glass, respectively. The pretreatment includes sludge washing, filtration, precipitation, and ion exchange processes to remove entrained solids, cesium, transuranics, technetium, and strontium. The cesium (Cs-137) and technetium (Tc-99) ion exchange removal

  15. Intermediate-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241AN102

    Microsoft Academic Search

    2001-01-01

    Ion exchange tests have been completed at the Savannah River Technology Center for British Nuclear Fuels Limited, Inc. as part of the Hanford River Protection Project. Radioactive cesium and technetium (pertechnetate form only) were removed by ion exchange from a sample of Envelope C salt solution from Hanford Tank 241-AN-102 (sample volume: approximately 18 L at 4.8 M Na plus).

  16. Intermediate-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241AN102

    Microsoft Academic Search

    2001-01-01

    Ion exchange tests have been completed at the Savannah River Technology Center for British Nuclear Fuels Limited, Inc. as part of the Hanford River Protection Project. Radioactive cesium and technetium (pertechnetate form only) were removed by ion exchange from a sample of Envelope C salt solution from Hanford Tank 241-AN-102 (sample volume: approximately 17 L at 4.8 M Na plus).

  17. Small-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241AN103

    Microsoft Academic Search

    Hassan

    2000-01-01

    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

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

    Microsoft Academic Search

    2010-01-01

    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

  19. Nanomaterials-Enhanced Electrically Switched Ion Exchange Process for Water Treatment

    SciTech Connect

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

    2009-01-01

    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.

  20. Inorganic ion-exchangers for the removal of zirconium, hafnium and niobium radioisotopes from aqueous solutions

    Microsoft Academic Search

    A. Dyer; F. H. Kadhim

    1989-01-01

    Studies were made on the uptake of zirconium, hafnium and niobium isotopes onto zeolites and amorphous zirconium phosphate. Ion exchange capacities and distribution coefficients were determined and the influence of pH examined. Kinetic experiments were made to determine the rates of uptake of the radioisotopes on the exchangers and to measure the leaching of isotopes from preloaded exchangers by synthetic

  1. Modelling the ion-exchange equilibrium in nanoporous materials

    E-print Network

    M. Luksic; V. Vlachy; B. Hribar-Lee

    2012-07-13

    Distribution of a two component electrolyte mixture between the model adsorbent and a bulk aqueous electrolyte solution was studied using the replica Ornstein-Zernike theory and the grand canonical Monte Carlo method. The electrolyte components were modelled to mimic the HCl/NaCl and HCl/CaCl_2 mixtures, respectively. The matrix, invaded by the primitive model electrolyte mixture, was formed from monovalent negatively charged spherical obstacles. The solution was treated as a continuous dielectric with the properties of pure water. Comparison of the pair distribution functions (obtained by the two methods) between the various ionic species indicated a good agreement between the replica Ornstein-Zernike results and machine calculations. Among thermodynamic properties, the mean activity coefficient of the invaded electrolyte components was calculated. Simple model for the ion-exchange resin was proposed. The selectivity calculations yielded qualitative agreement with the following experimental observations: (i) selectivity increases with the increasing capacity of the adsorbent (matrix concentration), (ii) the adsorbent is more selective for the ion having higher charge density if its fraction in mixture is smaller.

  2. Anion-exchange separations of metal ions in thiocyanate media.

    PubMed

    Fritz, J S; Kaminski, E E

    1971-05-01

    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

  3. Intermediate-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241-AN-102

    SciTech Connect

    King, W.D.

    2001-09-10

    Ion exchange tests have been completed at the Savannah River Technology Center for British Nuclear Fuels Limited, Inc. as part of the Hanford River Protection Project. Radioactive cesium and technetium (pertechnetate form only) were removed by ion exchange from a sample of Envelope C salt solution from Hanford Tank 241-AN-102 (sample volume: approximately 18 L at 4.8 M Na plus). The original sample was diluted and subjected to strontium/transuranics (Sr/TRU) precipitation and filtration processes before ion exchange processing was performed. Batch contact and column tests for the ion exchange removal of cesium and technetium were then completed on the Sr/TRU-decontaminated product. Previous ion exchange tests were conducted on a smaller portion (0.5 L) of the Tank 241-AN-102 supernate sample, which had been similarly pretreated, and the results were reported in a separate document.

  4. Intermediate-Scale Ion Exchange Removal of Cesium and Technetium from Hanford Tank 241-AN-102

    SciTech Connect

    King, W.D.

    2001-02-15

    Ion exchange tests have been completed at the Savannah River Technology Center for British Nuclear Fuels Limited, Inc. as part of the Hanford River Protection Project. Radioactive cesium and technetium (pertechnetate form only) were removed by ion exchange from a sample of Envelope C salt solution from Hanford Tank 241-AN-102 (sample volume: approximately 17 L at 4.8 M Na plus). The original sample was diluted and subjected to strontium/transuranics (Sr/TRU) precipitation and filtration processes before ion exchange processing was performed. Batch contact and column tests for the ion exchange removal of cesium and technetium were then completed on the Sr/TRU-decontaminated product. Previous ion exchange tests were conducted on a smaller portion (0.5 L) of the Tank 241-AN-102 supernate sample, which had been similarly pretreated, and the results were reported in a separate document.

  5. Integration of ion-exchange and nanofiltration processes for recovering Cr(III) salts from synthetic tannery wastewater.

    PubMed

    Gando-Ferreira, Licínio M; Marques, Joana C; Quina, Margarida J

    2015-09-01

    This study aims to investigate the possibility of integrating both ion-exchange (IX) and nanofiltration (NF) processes for the recovery of Cr(III) salts from a synthetic solution prepared with concentrations of Cr(III), [Formula: see text] and Cl(-) in the range of industrial effluents of tanneries. Ion exchange should be used as a pre-treatment for uptaking Cl(-) ions from the effluent, and thereafter the treated solution is fed to an NF unit to recover chromium sulphate salt for reuse in the tanning bath. The strong anionic resin Diaion PA316 was selected for evaluating chloride-sulphate ion-exchange equilibrium, with respect to mass of resin, NaCl concentration, temperature and ratio [Formula: see text]. It was observed that the separation factor, [Formula: see text], depends on the total electrolyte concentration and the ratio [Formula: see text] plays a role as well. Moreover, it was determined that the resin prefers sulphate over chloride since [Formula: see text] is less than 1. The performance of the NF process is dependent on [Formula: see text] and the rejection of Cr(III) may decrease from 90% to 70% as the ratio increases from 0.5 to 2. Regarding the integration of both IX and NF, the feed solution after treatement with the resin was fed to NF where the ratio of [Formula: see text] led to the best operating conditions for this process (90% of Cr(III) rejection and up to 77% for [Formula: see text] ions). This strategy may be considered as a sustainable approach since it permits to obtain a solution enriched in Cr(III) salt for reuse in the tanning process, thus contributing to environmental protection. PMID:25750988

  6. Taste masking of Etoricoxib by using ion-exchange resin.

    PubMed

    Patra, Sradhanjali; Samantaray, Rakesh; Pattnaik, Saswat; Barik, B B

    2010-01-01

    The present study was carried out in order to mask the bitter taste of the Etoricoxib by complexation with cation-exchange resin, Indion 204. The drug resin complexes (DRC) were prepared by batch process and efficient drug loading was obtained by using inactivated form of resin in the drug-resin ratio 1:3.3 with 30 min swelling time of resin in 25 mL of water with 5 min stirring time. Drug-resin complexes were characterized for dissolution studies and spectral studies. Drug release from drug-resin complex in salivary pH was insufficient to impart bitter taste. Volunteers rated the drug resin complex as tasteless and agreeable. PMID:19845450

  7. Improved Signal-to-noise Ratio in Glow Discharge Ion Trap Mass Spectrometryvia Pulsed Discharge Operation

    Microsoft Academic Search

    DOUGLAS C. DUCKWORTH; DAVID H. SMITH; SCOTT A. MCLUCKEY

    1997-01-01

    An improvement in the S\\/N ratio is reported for the analysis ence of intense matrix and discharge gas (Ar) ion beams.9 This of trace elements in brass by glow discharge ion trap mass observation was important because it allowed the dynamic spectrometry. This was achieved by synchronizing the pulsed range of the trap, which has an ion volume limited to

  8. Forbidden lines of np/q/ ions. I - Detailed balance and line intensity ratios

    NASA Technical Reports Server (NTRS)

    Kafatos, M.; Lynch, J. P.

    1980-01-01

    The detailed balance equations are solved in the ground state terms of 37 ions of C, N, O, Ne, Mg, Si, S and Fe; atomic data for 235 transitions of these ions are tabulated, and 14 line ratios of q = 2,4 ions and eight line ratios of q = 3 ions are graphed. Forbidden emission lines of these ions are in the far and near UV, visible, and near and far IR regions of the spectrum. In addition, detailed calculations of the relative populations of the levels of the ground state are presented as a function of temperature and density.

  9. Coupled acoustic-gravity field for dynamic evaluation of ion exchange with a single resin bead.

    PubMed

    Kanazaki, Takahiro; Hirawa, Shungo; Harada, Makoto; Okada, Tetsuo

    2010-06-01

    A coupled acoustic-gravity field is efficient for entrapping a particle at the position determined by its acoustic properties rather than its size. This field has been applied to the dynamic observation of ion-exchange reactions occurring in a single resin bead. The replacement of counterions in an ion-exchange resin induces changes in its acoustic properties, such as density and compressibility. Therefore, we can visually trace the advancement of an ion-exchange reaction as a time change in the levitation position of a resin bead entrapped in the field. Cation-exchange reactions occurring in resin beads with diameters of 40-120 microm are typically completed within 100-200 s. Ion-exchange equilibrium or kinetics is often evaluated with off-line chemical analyses, which require a batch amount of ion exchangers. Measurements with a single resin particle allow us to evaluate ion-exchange dynamics and kinetics of ions including those that are difficult to measure by usual off-line analyses. The diffusion properties of ions in resins have been successfully evaluated from the time change in the levitation positions of resin beads. PMID:20462180

  10. Ion-exchange, an Approach to Prepare an Oral Floating Drug Delivery System forDiclofenac

    Microsoft Academic Search

    Maryam Kouchak; Fatemeh Atyabi

    2004-01-01

    Using ion-exchange resins, a multiple-unit type of oral floating dosage system has been prepared to prolong gastric emptying time of dosage form. The system is composed of beads of drug-resin complex, which are loaded with bicarbonate ions and coated with a hydrophobic polymer. The system is so designed that when the beads reach the stomach, chloride ions are exchanged with

  11. Fast ion charge exchange spectroscopy adapted for tangential viewing geometry in LHD

    SciTech Connect

    Ito, T.; Osakabe, M.; Ida, K.; Yoshinuma, M.; Kobayashi, M.; Goto, M.; Isobe, M.; Toi, K.; Takeiri, Y.; Okamura, S. [National Institute for Fusion Science, Toki 509-5292 (Japan); Murakami, S.; Kobayashi, S. [Department of Nuclear Engineering, Kyoto University, Kyoto 606-8501 (Japan); Ogawa, K. [Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8601 (Japan)

    2010-10-15

    A tangential Fast Ion Charge eXchange Spectroscopy is newly applied on a Large Helical Device (LHD) for co/countercirculating fast ions, which are produced by high energy tangential negative-ion based neutral beam injection. With this new observation geometry, both the tangential-neutral beam (NB) and a low-energy radial-NB based on positive ions can be utilized as probe beams of the measurement. We have successfully observed Doppler-shifted H-alpha lights due to the charge exchange process between the probing NB and circulating hydrogen ions of around 100 keV in LHD plasmas.

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

    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.

  13. PRODUCTION OF NEGATIVE HEAVY ION BEAMS BY CHARGE EXCHANGE IN METAL VAPOUR

    E-print Network

    Paris-Sud XI, Université de

    1471 PRODUCTION OF NEGATIVE HEAVY ION BEAMS BY CHARGE EXCHANGE IN METAL VAPOUR J. HEINEMEIER and P and acceleration of negative heavy ion beams in a tandem accelerator. 03BCA intensities of 20 keV beams.of Li-, Be-separator sources. We found that this is the case even for a number of negative ions (Li-, Bé , B-, Na-, AI-, Câ

  14. Cementation of ILW ion exchange resins: Impact of sulfate ions released by radiolysis on hydrated matrix

    NASA Astrophysics Data System (ADS)

    Frizon, F.; Cau-dit-Coumes, C.

    2006-12-01

    Some of the ion exchange resins used during treatment of spent nuclear fuels are intermediate level radioactive wastes which may be damaged by radiolysis process, releasing sulfate ions directly into the cement-based encapsulating material. This work consists in an experimental study of the resulting sulfate attack on the properties of the hydrated matrix: dimensional stability, mineralogy and microstructure of the samples, as well as variations in the chemical composition of the curing solution, were studied during six months. Three sites of delayed ettringite formation were detected: into the cement matrix near the surface exposed to solution, localized in the interfacial transition zone between cement matrix and resins, or progressively replacing the portlandite that initially fulfilled the cracks of anionic resins. During the experiment period, the ettringite precipitation and the expansion detected were moderate, and did not lead to cracking. The material involved was considered as having a good resistance to sulfate attack.

  15. Intercalation of gaseous thiols and sulfides into Ag+ ion-exchanged aluminum dihydrogen triphosphate.

    PubMed

    Hayashi, Aki; Saimen, Hiroki; Watanabe, Nobuaki; Kimura, Hitomi; Kobayashi, Ayumi; Nakayama, Hirokazu; Tsuhako, Mitsutomo

    2005-08-01

    Ag(+) ion-exchanged layered aluminum dihydrogen triphosphate (AlP) with the interlayer distance of 0.85 nm was synthesized by the ion-exchange of proton in triphosphate with Ag(+) ion. The amount of exchanged Ag(+) ion depended on the concentration of AgNO(3) aqueous solution. Ag(+) ion-exchanged AlP adsorbed gaseous thiols and sulfides into the interlayer region. The adsorption amounts of thiols were more than those of sulfides, thiols with one mercapto group > thiol with two mercapto groups > sulfides, and depended on the amount of exchanged Ag(+) ion in the interlayer region. The thiols with one mercapto group were intercalated to expand the interlayer distance of Ag(+) ion-exchanged AlP, whereas there was no expansion in the adsorption of sulfide. In the case of thiol with two mercapto groups, there was observed contraction of the interlayer distance through the bridging with Ag(+) ions of the upper and lower sides of the interlayer region. PMID:16042448

  16. 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

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

    2010-01-01

    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.

  17. Bifunctional phenyl monophosphonic/sulfonic acid ion exchange resin and process for using the same

    DOEpatents

    Alexandratos, Spiro (Knoxville, TN); Shelley, Christopher A. (Knoxville, TN); Horwitz, E. Philip (Naperville, IL); Chiarizia, Renato (Elmhurst, IL); Gula, Michael J. (Chicago, IL); Xue, Sui (Darien, IL); Harvey, James T. (Naperville, IL)

    2002-01-01

    A cross-linked water-insoluble ion exchange resin comprised of polymerized monomers having a phenyl ring is disclosed. A contemplated resin contains (i) polymerized phenyl ring-containing monomers having a phosphonic acid ligand linked to the phenyl ring, (ii) about 2 to about 5 millimoles per gram (mmol/g) of phosphorus as phosphonic acid ligands, and (iii) a sufficient amount of a sulfonic acid ligand such that the ratio of mmol/g of phosphonic acid to mmol/g sulfonic acid is up to 3:1. A process for removing polyvalent metal cations from aqueous solution, and a process for removing iron(III) cations from acidic copper(II) cation-containing solutions that utilize the contemplated resin or other resins are disclosed.

  18. Bifunctional phenyl monophosphonic/sulfonic acid ion exchange resin and process for using the same

    DOEpatents

    Alexandratos, Spiro (Knoxville, TN); Shelley, Christopher A. (Knoxville, TN); Horwitz, E. Philip (Naperville, IL); Chiarizia, Renato (Elmhurst, IL)

    2001-01-01

    A cross-linked water-insoluble ion exchange resin comprised of polymerized monomers having a phenyl ring is disclosed. A contemplated resin contains (i) polymerized phenyl ring-containing monomers having a phosphonic acid ligand linked to the phenyl ring, (ii) about 2 to about 5 millimoles per gram (mmol/g) of phosphorus as phosphonic acid ligands, and (iii) a sufficient amount of a sulfonic acid ligand such that the ratio of mmol/g of phosphonic acid to mmol/g sulfonic acid is up to 3:1. A process for removing polyvalent metal cations from aqueous solution, and a process for removing iron(III) cations from acidic copper(II) cation-containing solutions that utilize the contemplated resin or other resins are disclosed.

  19. Low-loss glass waveguide optical power splitter by two-step ion-exchange technology

    NASA Astrophysics Data System (ADS)

    Zhou, Zigang

    2005-01-01

    A theoretical and experiment analysis of two-step ion-exchanged glass optical power splitter is reported. In order to facilitate quantitative analysis, we propose the rational model of physics for a 1×4 S-branch power splitter in glass. These surface half-round channel waveguides are fabricated by first performing a thermal exchange in Tl2SO4 through a mask patterned on the glass surface. The channel waveguides are then buried by second thermal Na+ exchange, unmasked ion exchange, in melt NaNO3. A buried optical power splitter of low insertion loss and uniformity loss has been realized.

  20. Ion exhange and molecular sorption of oxalic acid with a highly basic anion exchanger

    NASA Astrophysics Data System (ADS)

    Krisilova, E. V.; Oros, G. Yu.; Krisilov, A. V.; Selemenev, V. F.

    2014-04-01

    Ab initio modeling of a matrix fragment of resin and geometry optimization of the molecular structure of oxalic acid were performed. The isotherm of oxalic acid sorption with AV-17-8 anion exchange resin was obtained by the variable concentrations technique. The ion-exchange and molecular components of sorbate fixation with the ion exchanger were determined. The hydration of the highly basic anion exchanger that absorbed different quantities of dicarboxylic acid was evaluated by the centrifuging method. The dependence of the amount of water and sorbate concentration in the resin was linear antibatic.

  1. Ion exchange in the atomic energy industry with particular reference to actinide and fission product separation

    SciTech Connect

    Jenkins, I.L.

    1984-01-01

    Reviewed are some of the uses of ion exchange processes used 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 is given to safety in the use of ion exchangers and in safe methods of disposal of such materials. Full scale and pilot plant process descriptions are included as well as summaries of laboratory studies. 130 references.

  2. Enrichment of Magnesium Isotopes by N3O2 Azacrown Ion Exchange Resin

    Microsoft Academic Search

    D. W. Kim; B. K. Jeon; C. S. Kim; Y. S. Jeon

    2000-01-01

    The elution chromatographic separation of magnesium isotopes was investigated by chemical ion exchange with the synthesized 1,7-dioxa-4,10,13-triazacyclopentadecane-4,10,13-trimerrifield peptide resin [N3O2·3M]. The capacity of novel N3O2 azacrown ion exchanger was 0.21 meq\\/g dry resin. The heavier isotopes of magnesium concentrated in the resin phase, while the lighter isotopes are enriched in the solution phase. The glass ion exchange column used in

  3. High-resolution nitrogen and argon adsorption on ZSM-5 zeolites: effects of cation exchange and Si Al ratio

    Microsoft Academic Search

    Akira Saito; Henry C. Foley

    1995-01-01

    ZSM-5 zeolites with SiAl ratios of 23, 72 and >400 were synthesized in the laboratory as Na+ and cation (H+, Co2+, Cu2+, Fe2+ and Zn2+)-exchanged forms and were examined by nitrogen and argon porosimetry. Na-ZSM-5 of any SiAl ratio and high-alumina ZSM-5 (SiAl=23) zeolites of any exchanged cation display single transition adsorption isotherms (type I isotherm) for both nitrogen and

  4. Statistical and dynamical fluctuations of Binder ratios in heavy ion collisions

    E-print Network

    Zhiming Li; Fengbo Xiong; Yuanfang Wu

    2013-01-31

    Higher moments of net-proton Binder ratio, which is suggested to be a good experimental measurement to locate the QCD critical point, is measured in relativistic heavy ion collisions. We firstly estimate the effect of statistical fluctuations of the third and forth order Binder ratios. Then the dynamical Binder ratio is proposed and investigated in both transport and statistical models. The energy dependence of dynamical Binder ratios with different system sizes at RHIC beam scan energies are presented and discussed.

  5. Statistical and dynamical fluctuations of Binder ratios in heavy ion collisions

    E-print Network

    Li, Zhiming; Wu, Yuanfang

    2011-01-01

    Higher moments of net-proton Binder ratio, which is suggested to be a good experimental measurement to locate the QCD critical point, is measured in relativistic heavy ion collisions. We firstly estimate the effect of statistical fluctuations of the third and the forth order Binder ratios. Then the dynamical Binder ratio is proposed and investigated in both transport and statistical models. The energy dependence of dynamical Binder ratios with different system sizes at RHIC beam scan energies are presented and discussed.

  6. Use of petroleum reside for production of ion exchangers

    SciTech Connect

    Pokonova, Y.V.

    1995-03-10

    Weakly acidic commercial cation exchangers with a static exchange capacity of 4.8-6.7 meq{center_dot}{sup -1} and a mechanical strength of 90% have been synthesized from petroleum asphaltites, resorcinol, and furfural.

  7. Selectivity of alkali metal ion and lithium isotopes on ion exchangers prepared from MTi0.5Zr1.5(PO4)3(M = Li, Na)

    Microsoft Academic Search

    Hiroaki Takahashi; Takao Oi

    2001-01-01

    Inorganic ion exchangers, H-TZP(Li) and H-TZP(Na), in the hydrogen form have been prepared by ion exchange from the precursors, LiTi0.5Zr1.5(PO4)3 and NaTi0.5Zr1.5(PO4)3, respectively. The degrees of leaching of lithium and sodium ions were 99.7% and 68%, respectively. No substantial difference in ion exchange property was observed between the two ion exchangers. Both showed high selectivity toward lithium and sodium ions,

  8. Charge exchange of multiply charged fluorine and lithium ions with Ne atoms

    NASA Astrophysics Data System (ADS)

    Beigman, I. L.; Vishnyakov, E. A.; Luginin, M. S.; Ragozin, Evgenii N.; Tolstikhina, I. Yu

    2010-08-01

    The charge exchange of multiply charged fluorine and lithium ions with Ne atoms in a gas jet was recorded from the line spectra in the 125 — 350 Å range, which arise from the radiative decay of the excited states of Li II — III and F III — VIII ions populated in the charge exchange. In the F III — VI ion spectra obtained from the plasma — gas interaction region we observed transitions from levels with an open (partly filled or completely open) 2s-shell, which may be populated in sequential events of single-electron charge exchange as well as in double- and many-electron charge exchange. Partial cross sections were calculated for the single-electron charge exchange of F VIII ions with Ne atoms. By way of Hartree — Fock energy level calculations it was possible to reveal resonances between the ground states of k-fold (k = 1 — 4) ionised donor atoms and the states of k-fold excited multiply charged fluorine ion resulting from the k-fold charge exchange of F VIII ions. These resonances may be responsible for the relatively large cross sections of double- and many-electron charge exchange

  9. Development of Inorganic Ion Exchangers for Nuclear Waste Remediation

    SciTech Connect

    Clearfield, Abraham

    2000-06-01

    (1) Na2Ti2O3SiO4 {center_dot}2H2O(CST). This compound is the most highly selective Cs+ exchanger known and is also selective for Sr2+. The structure of this compound was solved from powder data and found to have a framework structure enclosing unidimensional tunnels. For alkali metals the exchange sites were found to vary depending upon the size of the cation. Li+ and Na+ are small enough to fit into framework sites which accommodate half the required cations. The remainder lie within the tunnels. The larger Cs+ cannot fit into the framework sites and can occupy only half the tunnel sites. Thus, only 25% of the total exchanger sites are available to Cs+. However, the Cs+ -O bonds that form are exactly equal to the sum of the radii for Cs+ and O2-. All other cations have a poorer fit and tend to be displaced by Cs+. In the presence of Na+ dual exchange occurs simultaneously as Na+ fills the framework sites and a second site inside the tunnels. As the sodium ion concentration increases the uptake of Cs+ site decreases to 0.05 - 0.1 meq/g in tank waste simulants. (2) Trisilicates: M(I)2M(IV) Si3O9 {center_dot}H2O, (M(I) = Na+, K+, M(IV) = Ti, Sn Zr, Ce). We have prepared a family of trisilicates and solved the crystal structures of three of them. These compounds have framework structures enclosing alternating large and small cavities. The cavity sizes vary with the size of the M(IV) cation. For example, the Ti phase does not take up Cs+ but the Zr phase exhibits very high Kd values for Cs+ (105 ml/g in groundwaters) and is even 1500 ml/g in 6M NaOH. The mixed phase Na2Zr0.75Sn0.25(Si3O9){center_dot}H2O shows even higher Kd values. The interchangeability of the M(IV) ion changes the size of the cavities and governs the selectivity. This is an excellent example of crystal engineering where substitutions within the framework change selectivities. (3) Pharmacosiderites: We have prepared a family of compounds based on the pharmacosiderite mineral structure, solved their structures and determined the ion siting. The titanium silicate version, K3H(TiO)4(SiO4)3 {center_dot} nH2O has a structure that is similar to that of the CST compound. It exhibits a high affinity for both Cs+ and Sr2+.7 The Kd values have been considerably improved by partial substitution of Ge for Ti, another example of controlling selectivity. The structure of the Sr2+ phase is under investigation. Sodium Nonatitanate: This compound, of composition Na4Ti9O20 {center_dot} nH2O is layered and the interlayer spacing varies with the water content. It is selective for Sr2+ in highly alkaline systems and the strontium is easily eluted with mild acid solutions. It works well under column flow conditions and is stable to irradiation. The main interference is Ca2+. Summary of Additional Studies: (4) We have developed a simple technique to remove Sr2+ from tank wastes that contain high levels of complexants. The scheme is to add a cation that is preferentially complexed and so releases the Sr2+ to the solution that is readily removed with our strontium selective sodium nonatitanate or CST. This really works! (5) We have prepared sodium micas and alumina and zirconia pillared clays that exhibit extremely high Kd values (>105) for Cs+ in contaminated groundwater. They are superior to zeolites for Cs+ removal and may be used as a barrier to Cs+ movement in soils. The sodium mica traps the Cs+ permanently. (6) We have prepared a sodium niobium silicate that appears to have a pyrochlore structure. It is highly selective for Sr2+ in the presence of Ca2+, Mg2+ and Na+.

  10. Kaon to Pion ratio in Heavy Ion Collisions

    E-print Network

    Jajati K. Nayak; Jan-e Alam; Pradip Roy; Abhee K. Dutt-Mazumder; Bedangadas Mohanty

    2005-11-25

    The momentum integrated Boltzmann equation has been used to study the evolution of strangeness of the strongly interacting system formed after the heavy ion collisions at relativistic energies.We argue that the experimentally observed non-monotonic, horn-like structure in the variation of the $K^+/\\pi^+$ with colliding energy appears due to the release of large number of colour degrees of freedom.

  11. Experimental Findings On Minor Actinide And Lanthanide Separations Using Ion Exchange

    SciTech Connect

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

    2013-09-17

    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.

  12. Chromium (III) recovery from waste acid solution by ion exchange processing using Amberlite IR-120 resin: batch and continuous ion exchange modelling.

    PubMed

    Alguacil, Francisco José; Alonso, Manuel; Lozano, Luis Javier

    2004-11-01

    The use of ion exchange technology was studied to remove chromium (III) from acidic waste solution by Amberlite IR-120 resin. Batch and column experimental tests were conducted to provide data for theoretical models and verify the system performance of the adsorption process. Results of batch equilibrium tests indicated that Langmuir isotherm describes well the adsorption process, whereas experimental data also provide evidence that, under the present experimental conditions, chromium (III) adsorption by Amberlite IR-120 resin is film-diffusion controlled; on the other hand, the theoretical model used in the present investigation was found to predict reasonably well the ion exchange breakthrough performance. PMID:15488570

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

    SciTech Connect

    Spires, Renee; Punch, Timothy; McCabe, Daniel

    2009-02-11

    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.

  14. Selectivity coefficient for Ca/Na ion exchange in highly compacted bentonite

    NASA Astrophysics Data System (ADS)

    Karnland, Ola; Birgersson, Martin; Hedström, Magnus

    Bentonite clay is proposed as buffer material around the waste canisters and as tunnel backfill material in several concepts for disposal of radioactive waste. The distribution of charge compensating cations in the bentonite is of interest for several reasons, one being possible release of colloid particles from the bentonite to groundwater with very low ionic strength. The cation distribution at equilibrium may be calculated for various relevant groundwater compositions by use of selectivity coefficients. However, present literature data generally concerns coefficients measured in batch experiments with high water-to-solid ratios. The basic aim with the present work was therefore to determine selectivity coefficients for sodium/calcium exchange in bentonite with low water-to-solid ratios, and thereby give a reliable base for calculating the cation distribution in a confined bentonite buffer with a relatively high density. In total, six tests with homo-ionic Na- and Ca-montmorillonite, prepared to three material densities, were equilibrated with test solutions of successively increasing concentration. The distribution of cations at equilibrium was measured by use of ion selective electrodes and ICP/AES, and selectivity coefficients were calculated according to the Gaines-Thomas convention. The obtained selectivity coefficient was found to be in the range of 3.8-7.8, which is similar to those previously reported for high water-to-solid ratios.

  15. Removal of uranium, arsenic, and nitrate by continuously regenerated ion exchange process

    SciTech Connect

    Chang, D.; Awad, J. [CH2M HILL, Santa Ana, CA (United States); Panahi, Z. [City of Riverside, CA (United States)

    1996-11-01

    Groundwater is the major source of water supply for the City of Riverside (the City). Groundwater from some of the local wells contains high levels of uranium, arsenic, and nitrate. The City is evaluating treatment technologies that can remove these contaminants, in order to be prepared to select appropriate treatment technologies when groundwater treatment is required. Treatment technologies identified by the USEPA as best available technology (BAT) for uranium and arsenic removal are coagulation/filtration, lime softening, ion exchange, and reverse osmosis. Among these technologies, ion exchange is the most cost-effective and suitable for wellhead treatment applications. Ion exchange is also effective for nitrate removal. An ion exchange pilot study was conducted for the removal of uranium, arsenic and nitrate from groundwater. This paper presents a summary of the tests results, conceptual design criteria, and preliminary cost estimate for a full-scale facility.

  16. Design and operation of an Ion-Exchange Pilot Facility for cesium and strontium sorption

    SciTech Connect

    Fowler, V.L.; Villiers-Fisher, J.F.; Hewitt, J.D.

    1989-10-01

    An Ion-Exchange Pilot Facility (IXPF) has been constructed to test fixed-bed ion-exchange for liquid waste streams generated at the Oak Ridge National Laboratory (ORNL). The test unit was designed based on the ion-exchange operation presently used at the Process Waste Treatment Plant (PWTP) but has the flexibility to vary operating parameters and analyze their effects. In this study, the IXPF was used to model the PWTP in order to identify ways in which the operating efficiency could be increased. The results indicate that significant improvements in the PWTP cannot be achieved by simply changing the operating procedures; flowsheet modifications and equipment upgrades will be necessary. The IXPF will be used to test potential flowsheets for the PWTP upgrade. The facility will also be a valuable tool for testing ion-exchange (IX) methods on other liquid wastes throughout ORNL. 4 refs., 12 figs., 5 tabs.

  17. Spin 1 frustrated antiferromagnet with biquadratic exchange and single ion anisotropy

    NASA Astrophysics Data System (ADS)

    Pires, A. S. T.

    2012-10-01

    The zero temperature properties, using the bond operator technique, are determined for the frustrated S=1 Heisenberg antiferromagnetic model plus nearest-neighbor biquadratic exchange interaction and single ion anisotropy on a two dimensional square lattice.

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

    SciTech Connect

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

    2008-08-26

    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.

  19. SEPARATION OF PROTEINS BY ION EXCHANGE AND MEMBRANE CHROMATOGRAPHY: BUFFER COMPOSITION, INTERFERING IMPURITIES AND FOULING CONSIDERATIONS

    E-print Network

    Imam, Tahmina

    2010-01-16

    solution properties (pH, ionic strength, buffer ions) in order to maximize lysozyme purification by a strong cation exchange resin. The interaction of phytic acid, a major impurity, present in transgenic rice extracts, that contributes to decreased lysozyme...

  20. Equilibrium data for cesium ion exchange of Hanford CC and NCAW tank waste

    SciTech Connect

    Bray, L.A.; Carson, K.J.; Elovich, R.J.; Kurath, D.E.

    1996-04-01

    Hanford alkaline waste storage-tank contents will be processed to remove the soluble salts. A major fraction of these solutions will require cesium recovery to produce a low-level waste (LLW). The technology for decontamination of high-level alkaline waste and sludge wash waters is being developed. At the request of Westinghouse Hanford Company (WHC), the Pacific Northwest Laboratory (PNL) has studied several ion exchange materials for the recovery of cesium from Hanford waste tanks. The WHC program was divided into tow main tasks, (1) to obtain equilibrium data for cesium ion exchange, and (2) to evaluate ion exchange column performance. The subject of this letter report is the measurement of batch distribution coefficients for several ion exchange media for a range of operating conditions for two types of waste; complexant concentrate (CC) and neutralized current acid waste (NCAW).

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

    NASA Astrophysics Data System (ADS)

    Nakayama, Morio

    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.

  2. Ratios

    NSDL National Science Digital Library

    2005-01-01

    This "homework help" lesson introduces students to ratios, ratio language, equivalent ratios, and allows students to practice with a set of problems at the end. The lesson is divided into four parts: First Glance, In Depth, Examples, and Workout.

  3. Increasing RO efficiency by chemical-free ion-exchange and Donnan dialysis: Principles and practical implications.

    PubMed

    Vanoppen, Marjolein; Stoffels, Griet; Demuytere, Célestin; Bleyaert, Wouter; Verliefde, Arne R D

    2015-09-01

    Ion-exchange (IEX) and Donnan dialysis (DD) are techniques which can selectively remove cations, limiting scaling in reverse osmosis (RO). If the RO concentrate could be recycled for regeneration of these pre-treatment techniques, RO recovery could be largely increased without the need for chemical addition or additional technologies. In this study, two different RO feed streams (treated industrial waste water and simple tap water) were tested in the envisioned IEX-RO and DD-RO hybrids including RO concentrate recycling. The efficiency of multivalent cation removal depends mainly on the ratio of monovalent to multivalent cations in the feed stream, influencing the ion-exchange efficiency in both IEX and DD. Since the mono-to-multivalent ratio was very high in the waste water, the RO recovery could potentially be increased to 92%. For the tap water, these high RO recoveries could only be reached by adding additional NaCl, because of the low initial monovalent to multivalent ratio in the feed. In both cases, the IEX-RO hybrid proved to be most cost-efficient, due to the high current cost of the membranes used in DD. The membrane cost would have to decrease from ±300 €/m² to 10-30 €/m² - comparable to current reverse osmosis membranes - to achieve a comparable cost. In conclusion, the recycling of RO concentrate to regenerate ion exchange pre-treatment techniques for RO is an interesting option to increase RO recovery without addition of chemicals, but only at high monovalent/multivalent cation-ratios in the feed stream. PMID:25996753

  4. Radiative and nonradiative deexcitation rates and branching ratios of multi-excited Li-like ion

    SciTech Connect

    Karim, K.R.; Ruesink, M.; Bhalla, C.P.

    1993-05-01

    Radiative transition rates, autoionization rates, transition energies and branching ratios are presented for 1s2{ell}n{ell}{prime} autoionizing states (n=2-8) of selected Li-like ions. Such states are produced in high-temperature plasmas by dielectronic recombination of heliumlike ions, and in certain ion-atom collision processes such as resonant transfer and excitation. The calculation has been done in the intermediate coupling scheme with the inclusion of effects due to configuration interaction.

  5. Knowledge based system for runtime controlling of multiscale model of ion-exchange solvent extraction

    NASA Astrophysics Data System (ADS)

    Macio?, Piotr; Gotfryd, Leszek; Macio?, Andrzej

    2012-09-01

    The hereby paper concerns the issue of solution of runtime controlling of multiscale model of ion-exchange solvent extraction. It is based on cooperation of a framework applying Agile Multiscale Modeling Methodology (AM3), and the REBIT Knowledge Based System. Ion-exchange solvent extraction has been shortly introduced. Design assumptions of AM3 and theoretical basis of REBIT have been described. Designed workflows and rules for simple laminar/ turbulent flow and extraction processes have been shown.

  6. An evaluation of the physicochemical degradation of gold ion-exchange resins in hypochlorite solutions

    Microsoft Academic Search

    Kathryn C. Sole; Peihao Qi; J. Brent Hiskey

    1993-01-01

    The long-term operating characteristics of ion-exchange resins suitable for the hydrometallurgical recovery of precious metals\\u000a remain largely unknown. This study examines some physicochemical properties of two promising ion-exchange resins for gold,\\u000a SR-3 and PAZ-8, when subjected to experimental conditions similar to those of a typical alkaline-chlorination gold recovery\\u000a process. It is shown that the degradation behavior may be related to

  7. A cation exchange resin bead-based microscale electrolytic suppressor for capillary ion chromatography

    Microsoft Academic Search

    Feifang Zhang; Yapu Li; Bingcheng Yang; Xinmiao Liang

    2011-01-01

    A cation exchange resin (CER) bead-based microscale electrolytic suppressor for capillary ion chromatography (CIC) has been fabricated and evaluated. Relative to common ion exchange membrane, the use of CER beads presents a simple way to fabricate a microscale suppressor due to its small surface area and spherical shape. The internal volume of the device is ?600nL, which matches the requirements

  8. Management of Spent Organic Ion-Exchange Resins by Photochemical Oxidation

    Microsoft Academic Search

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

    2003-01-01

    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

  9. Expanded-bed adsorption utilizing ion-exchange resin to purify extracellular ?-galactosidase

    Microsoft Academic Search

    José Antonio Marques Pereira; Paulo De Tarso Vieira E Rosa; Glaucia Maria Pastore; Cesar Costapinto Santana

    1998-01-01

    The application of expanded-bed ion-exchange resins allows the elimination of intermediary particulate separation steps like\\u000a filtration or centrifugation prior to adsorption steps in enzyme-purification processes from crude fermentation broths. This\\u000a work is concerned with the experimental evaluation data of a process related to the adsorption of an extracellular p-galactosidase\\u000a from the fungiScopulariopsis. The protein recovery in the ion-exchange resin Accell

  10. Hydraulic Testing of Ion Exchange Resins for Cesium Removal from Hanford Tank Waste

    Microsoft Academic Search

    Kriston P. Brooks; Brian S. Augspurger; David L. Blanchard; Judith M. Cuta; Sandra K. Fiskum; Murray R. Thorson

    2006-01-01

    The granular ion exchange resin SuperLig 644 is the ion exchange resin of choice for Cs separation from Hanford tank wastes. Current testing activities are evaluating both ground gel and spherical resorcinol?formaldehyde (RF) resins as alternatives to the sole?source supplied SL?644 while achieving comparable loading and elution performance. The purpose of this testing was then to compare the bed forces,

  11. Technology transfer: Ion exchange resins for Technetium-99 removal from X-705 raffinates

    SciTech Connect

    Deacon, L.E.; Greiner, M.J.

    1982-12-03

    An ion exchange process will be used at Portsmouth to remove Technetium-99 from uranium recovery waste solutions (raffinates). Subsequent treatment will then remove nitrates from the raffinates by a biodenitrification process prior to discharge to receiving streams to meet environmental standards for liquid wastes. Ion exchange process parameters affecting safe and efficient raffinate treatment have been examined in the laboratory, and results are described in this report. 4 refs., 3 figs., 6 tabs.

  12. Ion exchange behavior among metal trisilicates: probing selectivity, structures, and mechanism

    E-print Network

    Fewox, Christopher Sean

    2008-10-10

    ..................................................................................... 4 1.4. Purpose and overview .................................................................. 11 II STRUCTURAL AND MECHANISTIC INVESTIGATION OF RUBIDIUM ION EXCHANGE IN POTASSIUM ZIRCONIUM TRISILICATE... with umbite topology will be elucidated. In Chapter II, the structure of the rubidium zirconium trisilicate, Rb2ZrSi3O9•H2O, will be discussed along with an examination of the mechanism of ion exchange. Among alkali cations, the potassium zirconium...

  13. Effect of Temperature on Air Adsorption onto Alkali Metal Ion-Exchanged ZSM-5 Zeolites

    Microsoft Academic Search

    MASAHIRO KATOH; KAZUYUKI KATAYAMA; TAHEI TOMIDA

    1999-01-01

    Alkali metal ion-exchanged ZSM-5 zeolites, M-ZSM-5 (M = Li, Na, K, Rb, and Cs), were prepared from Na-ZSM-5 by a conventional ion-exchange method, and their abilities to adsorb air were investigated through measurements of the amount of gases adsorbed as determined from elution curves on chromatography. The interaction of adsorbed gases and cations of M-ZSM-5 were examined from IR spectra

  14. Comprehensive Scale Testing of the Ion Exchange Removal of Cesium and Technetium from Hanford Tank Wastes

    Microsoft Academic Search

    Daniel J. McCabe; Neguib M. Hassan; William D. King; John L. Steimke; Michael A. Norato; L. Larry Hamm; Lawrence N. Oji

    2001-01-01

    Highly selective ion exchange materials will be used to remove radionuclides from tank waste at the Hanford site as part of the River Protection Project. Testing in support of facility design was performed with different sizes of ion exchange columns to provide a basis for comparing results obtained using small-scale with radioactive samples and full design-height (i.e., pilot-scale) with simulant.

  15. Nonlinear inverse problem for a model of ion-exchange filter: numerical recovery of parameters

    E-print Network

    the water treatment plant designed to compensate for loss of water coolant in the power plant cycle. One is the use of ion-exchange materials, which require periodic regeneration [9-12]. Water treatment using-exchange filters results in highly mineralized, acidic and alkaline waste water [9]. With the continuous

  16. A novel series of photocatalysts with an ion-exchangeable layered structure of niobate

    Microsoft Academic Search

    K. Domen; J. Yoshimura; T. Sekine; A. Tanaka; T. Onishi

    1990-01-01

    Ion-exchangeable niobates, A(Mn-1NbnO3n+1) (A = Na, K, Rb, Cs; M = La, Ca etc.), with a layered perovskite structure are found to show a unique photocatalytic activity, especially in those H+-exchanged forms, for H2 evolution from aqueous alcohol solutions as well as O2 evolution from an aqueous silver nitrate solution.

  17. Effect of hydrochloric acid on the transport properties of tin through ion-exchange membranes

    Microsoft Academic Search

    M. García-Gabaldón; V. Pérez-Herranz; J. García-Antón; J. L. Guiñón

    2009-01-01

    This work presents a study of the transport properties of two ion-exchange membranes present in an electrochemical reactor used to process the wasted and rinse baths of the electroless plating of polymers industry. The influence of the hydrochloric acid on the transport properties of tin through both cation- and anion-exchange membranes has been evaluated by chronopotentiometry. The shape of the

  18. 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...

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

    E-print Network

    Latturner, Susan

    -cage stoichiometry, [(AlSiO4)3]32 , requires charge balancing cationic species within the cage. These M+ cations, like more complex aluminosilicate zeolites, are able to exchange their charge balancing cationic that some water content is required to promote ion exchange.4 On the other hand, neat solvents

  20. Calcium Isotope Effect in Calcium Ion Exchange with a Fluid Phase Containing a Macrocyclic Compound

    Microsoft Academic Search

    B. E. Jepson; W. F. Evans

    1987-01-01

    The separation coefficient for calcium isotope exchange with a macrocyclic polyether was measured by ion exchange chromatography. The isotopic enrichment proceeds according to the chemical exchange reaction:where L represents the macrocyclic polyether 18-crown-6. The observed -separation coefficient for the calcium 40\\/44 isotope pair, ?(40\\/44), was 4.9×10 (±1.3×10, 95% C.L.) with calcium-40 enriched in the fluid phase. A sulfonic acid resin

  1. A review of studies on ion thruster beam and charge-exchange plasmas

    NASA Technical Reports Server (NTRS)

    Carruth, M. R., Jr.

    1982-01-01

    Various experimental and analytical studies of the primary beam and charge-exchange plasmas of ion thrusters are reviewed. The history of plasma beam research is recounted, emphasizing experiments on beam neutralization, expansion of the beam, and determination of beam parameters such as electron temperature, plasma density, and plasma potential. The development of modern electron bombardment ion thrusters is treated, detailing experimental results. Studies on charge-exchange plasma are discussed, showing results such as the relationship between neutralizer emission current and plasma beam potential, ion energies as a function of neutralizer bias, charge-exchange ion current collected by an axially moving Faraday cup-RPA for 8-cm and 30-cm ion thrusters, beam density and potential data from a 15-cm ion thruster, and charge-exchange ion flow around a 30-cm thruster. A 20-cm thruster electrical configuration is depicted and facility effects are discussed. Finally, plasma modeling is covered in detail for plasma beam and charge-exchange plasma.

  2. Measurement of isotope ratio of Ca{sup +} ions in a linear Paul Trap

    SciTech Connect

    Hashimoto, Y.; Minamino, K.; Nagamoto, D.; Hasegawa, S. [Department of Quantum Engineering and Systems Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)

    2009-03-17

    Measurement of isotope ratios of Calcium is very useful in many fields. So we demonstrated the measurement of isotope ratios of {sup 40}Ca{sup +}(abundance 96.4%) to {sup 44}Ca{sup +}(2.09%) ions in a linear Paul trap with several laser lights tuning to the isotope shifts. And we found that the experimental parameters had large influences on the measurement of the isotope ratios.

  3. Influence of ion bombardment induced patterning of exchange bias in pinned artificial ferrimagnets on the interlayer exchange coupling

    SciTech Connect

    Hoeink, V.; Schmalhorst, J.; Reiss, G. [Thin Films and Nanostructures, Department of Physics, Bielefeld University, P.O. Box 100131, 33501 Bielefeld (Germany); Weis, T.; Lengemann, D.; Engel, D.; Ehresmann, A. [Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), Kassel University, Heinrich-Plett-Strasse 40, D-34132 Kassel (Germany)

    2008-06-15

    Artificial ferrimagnets have many applications as, e.g., pinned reference electrodes in magnetic tunnel junctions. It is known that the application of ion bombardment (IB) induced patterning of the exchange bias coupling of a single layer reference electrode in magnetic tunnel junctions with He ions is possible. For applications as, e.g., special types of magnetic logic, a combination of the IB induced patterning of the exchange bias coupling and the implementation of an artificial ferrimagnet as reference electrode is desirable. Here, investigations for a pinned artificial ferrimagnet with a Ru interlayer, which is frequently used in magnetic tunnel junctions, are presented. It is shown that in this kind of samples the exchange bias can be increased or rotated by IB induced magnetic patterning with 10 keV He ions without a destruction of the antiferromagnetic interlayer exchange coupling. An IrMn/Py/Co/Cu/Co stack turned out to be more sensitive to the influence of IB than the Ru based artificial ferrimagnet.

  4. Quantifying exchange coupling in f-ion pairs using the diamagnetic substitution method

    SciTech Connect

    Lukens, Wayne W.; Walter, Marc D.

    2010-04-01

    One of the challenges in the chemistry of actinide and lanthanide (f-ion) is quantifying exchange coupling between f-ions. While qualitative information about exchange coupling may be readily obtained using the diamagnetic substitution approach, obtaining quantitative information is much more difficult. This article describes how exchange coupling may be quantified using the susceptibility of a magnetically isolated analog, as in the diamagnetic substitution approach, along with the anisotropy of the ground state as determined by EPR spectroscopy. Several examples are used to illustrate and test this approach.

  5. Donnan dialysis of transition metal ions using anion exchange membrane modified with Xylenol Orange

    SciTech Connect

    Sawicka, B.; Brajter, K.; Trojanowicz, M.; Kado, B. (Univ. of Warsaw (Poland))

    1991-01-01

    A chelating ion-exchange membrane was obtained by modification of a PTFE-based anion-exchange membrane with Xylenol Orange. Its utility for dialysis of Cu(II), Ni(II), Mn(II), and Zn(II) was investigated by using receiver solutions without and with iminodiacetate. 1,2-diaminocyclohexanetetraacetic acid, and tetraethylenepentamine. In comparison to commercial PTFE cation-exchange membranes, modified chelating membranes exhibit for the metal ions investigated a larger differentiation of retention in the membrane phase and transport-to-receiver solution depending on the modifier used and the composition of the receiver solution.

  6. ANALYTICAL POTENTIAL OF SEPARATIONS BY LIQUID ION EXCHANGE

    Microsoft Academic Search

    C. F. Coleman; C. A. Jr. Blake; K. B. Brown

    1962-01-01

    While extractions by liquid anion exchange with alkylamines or ; quaternary ammoniums and by liquid cation exchange with (especially) ; organophosphorus acids are being developed intensively for chemical processing, ; they appear as yet to be used considerably less than other types of extractions ; in analytical chemistry. Thus, a representative compilation of extractions is ; summarized, and the controlling

  7. Charge-to-mass-ratio-dependent ion heating during magnetic reconnection in the MST RFP

    SciTech Connect

    Kumar, S. T. A.; Almagri, A. F.; Den Hartog, D. J.; Nornberg, M. D.; Sarff, J. S.; Terry, P. W. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States) [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Craig, D. [Wheaton College, Wheaton, Illinois 60187 (United States)] [Wheaton College, Wheaton, Illinois 60187 (United States)

    2013-05-15

    Temperature evolution during magnetic reconnection has been spectroscopically measured for various ion species in a toroidal magnetized plasma. Measurements are made predominantly in the direction parallel to the equilibrium magnetic field. It is found that the increase in parallel ion temperature during magnetic reconnection events increases with the charge-to-mass ratio of the ion species. This trend can be understood if the heating mechanism is anisotropic, favoring heating in the perpendicular degree of freedom, with collisional relaxation of multiple ion species. The charge-to-mass ratio trend for the parallel temperature derives from collisional isotropization. This result emphasizes that collisional isotropization and energy transfer must be carefully modeled when analyzing ion heating measurements and comparing to theoretical predictions.

  8. Advanced Ion Exchange Softening. Training Module 2.212.4.77.

    ERIC Educational Resources Information Center

    McMullen, L. D.

    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…

  9. Comparison of the ion-exchange behaviour of zirconium, thorium, vanadium, uranium, stannic and titanium tungstates.

    PubMed

    Qureshi, M; Gupta, J P; Sharma, V

    1974-01-01

    Zirconium, thorium, uranium, vanadium, stannic and titanium tungstates have been prepared and their properties such as ion-exchange capacity, K(d) values of metal ions, chemical composition and stability have been compared. Titanium tungstate was found to be the most stable, and to have negligible capacity for tervalent cations. PMID:18961426

  10. Carbon dioxide sequestration through novel use of ion exchange fibers (IX-fibers)

    Microsoft Academic Search

    S. Padungthon; J. E. Greenleaf; A. K. Sengupta

    2011-01-01

    Electrical power generation and metal removal processes are practiced globally and share two common attributes that make them ideal candidates to be incorporated in a novel carbon dioxide sequestration scheme using ion exchange fibers (IX-fibers). First, the softening of boiler feed water used in power generation and the removal of metals from finishing wastewaters often employs the use of ion

  11. ROTARY FILTER FINES TESTING FOR SMALL COLUMN ION EXCHANGE

    SciTech Connect

    Herman, D.

    2011-08-03

    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.

  12. CHARACTERIZATION OF CYCLED SPHERICAL RESORCINOL-FORMALDEHYDE ION EXCHANGE RESIN

    SciTech Connect

    Nash, C.; Duignan, M.

    2010-02-23

    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.

  13. Desalination by electrodialysis with the ion-exchange membrane prepared by radiation-induced graft polymerization

    NASA Astrophysics Data System (ADS)

    Choi, Seong-Ho; Han Jeong, Young; Jeong Ryoo, Jae; Lee, Kwang-Pill

    2001-01-01

    Ion-exchange membranes modified with the triethylamine [-N(CH 2CH 3) 3] and phosphoric acid (-PO 3 H) groups were prepared by radiation-induced grafting of glycidyl methacrylate (GMA) onto the polyolefin nonwavon fabric (PNF) and subsequent chemical modification of poly(GMA) graft chains. The physical and chemical properties of the GMA-grafted PNF and the PNF modified with ion-exchange groups were investigated by SEM, XPS, TGA, and DSC. Furthermore, electrochemical properties such as specific electric resistance, transport number of K +, and desalination were examined. The grafting yield increased with increasing reaction time and reaction temperature. The maximum grafting yield was obtained with 40% (vol.%) monomer concentration in dioxane at 60°C. The content of the cation- and anion-exchange group increased with increasing grafting yield. Electrical resistance of the PNF modified with TEA and -PO 3 H group decreased, while the water uptake (%) increased with increasing ion-exchange group capacities. Transport number of the PNF modified with ion-exchange group were the range of ca. 0.82-0.92. The graft-type ion-exchange membranes prepared by radiation-induced graft copolymerization were successfully applied as separators for electrodialysis.

  14. Ion exchange in an alumo-boro-silicate glass especially developed for multimode integrated optical elements

    NASA Astrophysics Data System (ADS)

    Kaps, C. H.; Karthe, Wolfgang; Mueller, Rudolf; Possner, Torsten; Schreiter, G.

    1989-12-01

    Commercially available glasses are not optimized for ion exchange in order to fabricate multimode optical waveguides. For most of the glass types the refractive index increase and the waveguide thickness are too small and the loss is increased. Therefore in the last years special glass types have been developed for thallium and silver ion exchange, respectively. By this type of exchange waveguides can be fabricated with refractive index profiles sufficiently matched to that one of 50 ?m-graded-index fibers. However, thallium is a highly toxic ion and for silver-sodium exchange a yellow cnuloring of the glasses appears due to reducing impurities as, e. g., As3+, Fe2+ and Sb3+./1/.

  15. Evolution of ion-exchange: from Moses to the Manhattan Project to modern times.

    PubMed

    Lucy, Charles A

    2003-06-01

    This article explores the history of ion-exchange from records of desalination in the Old Testament and the writings of Aristotle, to the identification of the phenomenon of ion-exchange by two English agricultural chemists, to the invention of suppressed conductivity by Small et al. [Anal. Chem. 54 (1975) 462]. It then focuses on the characteristics of the gradual and continuous evolution of ion chromatography with suppressed conductivity to its current state, with an emphasis on those discoveries that punctuated or revolutionized this evolution. PMID:12877196

  16. Automated resource-saving technology of ion-exchange water treatment

    NASA Astrophysics Data System (ADS)

    Livshits, M.

    2015-01-01

    Stable high quality of the purified water can be provided by adaptive control of water-treatment installations with the observer in a loop of the control system on the basis of observer of ion exchange processes. To obtain this goal the following problems have been solved: the hierarchic structure of water treatment system is developed; the system of water treatment quality criteria for ion exchange processes is developed; the created mathematical model of ionic exchange processes is functionally oriented to application in control system as an observer; methodologies of identification of a mathematical model of ionic exchange processes is developed; verification of the mathematical model of ionic exchange is performed on experimental-industrial basis; automatic control system of water treatment with observer in the loop is developed for low-waste installation of a heat supply system.

  17. Ratios

    NSDL National Science Digital Library

    2010-07-23

    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.

  18. An age-dependent alteration of the respiratory exchange ratio in the db/db mouse

    PubMed Central

    Choi, Hye-Min; Kim, Hae Rim; Kim, Eun-Kyoung; Byun, Yong Sub; Won, Young-Suk; Yoon, Won-Ki; Kim, Hyoung-Chin; Kang, Jong-Goo

    2015-01-01

    The leptin receptor-deficient db/db mouse is a rodent model of type 2 diabetes and obesity. Diabetes in db/db mice shows an age-dependent progression, with early insulin resistance followed by an insulin secretory defect resulting in profound hyperglycemia. However, there is insufficient data on agedependent changes of energy metabolism in db/db mice. We demonstrated an age-dependent decrease in the respiratory exchange ratio (RER), calculated by a ratio of VO2/VCO2, in db/db mice. The RER determined by indirect calorimetry, was 1.03 in db/db mice under 6 weeks of age, which were similar to those in heterozygote (db/+) and wild-type (+/+) mice. However, RER decreased from approximately 0.9 to 0.8 by 10 weeks of age and subsequently returned to approximately 0.9 at 22 weeks of age. The changes in RER were concurrent with the alterations in body weight and blood glucose level. However, other metabolic indicators such as glucose tolerance, changes in body fat mass, and urinary glucose levels, did not change with age. The results suggested that the energy source utilized in db/db mice changed with the age-related progression of diabetes. PMID:25806077

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

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

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

    PubMed Central

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

    2014-01-01

    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

  1. On the increase of the intensity ratio of doubly charged ions to singly charged ions for liquid gold and copper ion sources

    Microsoft Academic Search

    Yasuhito Gotoh; Hiroshi Tsuji; Junzo Ishikawa

    2001-01-01

    The reason for the increase of R21 which is defined by the intensity ratio of the doubly charged ions to the singly charged ions, was studied. Based on the conventional field evaporation theory, an increase in the electric field and\\/or the source temperature is considered to be attributable. We took the fact that R21 turned to decrease at the higher

  2. Rate of decrease in the intensity ratio of doubly charged ions to singly charged ions in liquid-metal ion source with gold-based alloy

    Microsoft Academic Search

    Y. Gotoh; H. Tsuji; J. Ishikawa

    1998-01-01

    We have investigated the intensity ratio of doubly charged ions to singly charged ions (R21) of Au82Si18 and Au66Sb34 ion sources. R21 was measured as a function of emission current, in order to establish the empirical relation between the electric field at the ionization point and the emission current. The rate of decrease in R21 was represented by the slope

  3. Numerical modeling of field-assisted ion-exchanged channel waveguides by the explicit consideration of space-charge buildup.

    PubMed

    Mrozek, Piotr

    2011-08-01

    A numerical model explicitly considering the space-charge density evolved both under the mask and in the region of optical structure formation was used to predict the profiles of Ag concentration during field-assisted Ag(+)-Na(+) ion exchange channel waveguide fabrication. The influence of the unequal values of diffusion constants and mobilities of incoming and outgoing ions, the value of a correlation factor (Haven ratio), and particularly space-charge density induced during the ion exchange, on the resulting profiles of Ag concentration was analyzed and discussed. It was shown that the incorporation into the numerical model of a small quantity of highly mobile ions other than exclusively Ag(+) and Na(+) may considerably affect the range and shape of calculated Ag profiles in the multicomponent glass. The Poisson equation was used to predict the electric field spread evolution in the glass substrate. The results of the numerical analysis were verified by the experimental data of Ag concentration in a channel waveguide fabricated using a field-assisted process. PMID:21833126

  4. 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

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

    2000-01-01

    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

  5. In-ESI source hydrogen/deuterium exchange of carbohydrate ions.

    PubMed

    Kostyukevich, Yury; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene

    2014-03-01

    We present the investigation of hydrogen/deuterium (H/D) exchange of carbohydrates ions occurring in the electrospray ion source. The shape of the deuterium distribution was observed to be considerably dependent on the temperature of the ion transfer tube and the solvent used. If deuterated alcohol (EtOD or MeOD) or D2O/deuterated alcohol is used as an electrospray solvent, then for high temperatures (>350 °C), intensive back exchange is observed, resulting in ?30% depth of the deuterium exchange. At low temperatures (<150 °C), the back exchange is weaker and the depth of the deuterium exchange is ?70%. In the intermediate temperature region (?250 °C), the deuterium distribution is unusually wide for methanol and bimodal for ethanol. The addition of 1% formic acid results in low (?30%) depth of the deuterium exchange for any temperature in the operating region. The bimodal distribution for the ethanol can be possibly explained by the presence of differently folded gas-phase ions of carbohydrates. PMID:24499243

  6. Ion-exchange selectivity of diclofenac, ibuprofen, ketoprofen, and naproxen in ureolyzed human urine.

    PubMed

    Landry, Kelly A; Sun, Peizhe; Huang, Ching-Hua; Boyer, Treavor H

    2015-01-01

    This research advances the knowledge of ion-exchange of four non-steroidal anti-inflammatory drugs (NSAIDs) - diclofenac (DCF), ibuprofen (IBP), ketoprofen (KTP), and naproxen (NPX) - and one analgesic drug-paracetamol (PCM) - by strong-base anion exchange resin (AER) in synthetic ureolyzed urine. Freundlich, Langmuir, Dubinin-Astakhov, and Dubinin-Radushkevich isotherm models were fit to experimental equilibrium data using nonlinear least squares method. Favorable ion-exchange was observed for DCF, KTP, and NPX, whereas unfavorable ion-exchange was observed for IBP and PCM. The ion-exchange selectivity of the AER was enhanced by van der Waals interactions between the pharmaceutical and AER as well as the hydrophobicity of the pharmaceutical. For instance, the high selectivity of the AER for DCF was due to the combination of Coulombic interactions between quaternary ammonium functional group of resin and carboxylate functional group of DCF, van der Waals interactions between polystyrene resin matrix and benzene rings of DCF, and possibly hydrogen bonding between dimethylethanol amine functional group side chain and carboxylate and amine functional groups of DCF. Based on analysis of covariance, the presence of multiple pharmaceuticals did not have a significant effect on ion-exchange removal when the NSAIDs were combined in solution. The AER reached saturation of the pharmaceuticals in a continuous-flow column at varying bed volumes following a decreasing order of DCF > NPX ? KTP > IBP. Complete regeneration of the column was achieved using a 5% (m/m) NaCl, equal-volume water-methanol solution. Results from multiple treatment and regeneration cycles provide insight into the practical application of pharmaceutical ion-exchange in ureolyzed urine using AER. PMID:25462757

  7. Adsorption of three pharmaceuticals on two magnetic ion-exchange resins.

    PubMed

    Jiang, Miao; Yang, Weiben; Zhang, Ziwei; Yang, Zhen; Wang, Yuping

    2015-05-01

    The presence of pharmaceuticals in aquatic environments poses potential risks to the ecology and human health. This study investigated the removal of three widely detected and abundant pharmaceuticals, namely, ibuprofen (IBU), diclofenac (DC), and sulfadiazine (SDZ), by two magnetic ion-exchange resins. The adsorption kinetics of the three adsorbates onto both resins was relatively fast and followed pseudo-second-order kinetics. Despite the different pore structures of the two resins, similar adsorption patterns of DC and SDZ were observed, implying the existence of an ion-exchange mechanism. IBU demonstrated a combination of interactions during the adsorption process. These interactions were dependent on the specific surface area and functional groups of the resin. The adsorption isotherm fittings verified the differences in the behavior of the three pharmaceuticals on the two magnetic ion-exchange resins. The presence of Cl(-) and SO4(2-) suppressed the adsorption amount, but with different inhibition levels for different adsorbates. This work facilitates the understanding of the adsorption behavior and mechanism of pharmaceuticals on magnetic ion-exchange resins. The results will expand the application of magnetic ion-exchange resins to the removal of pharmaceuticals in waters. PMID:25968278

  8. Calculation of exchange constants in spinel ferrites with magnetic S-state ions

    NASA Astrophysics Data System (ADS)

    Zuo, Xu; He, Yongxue; Yang, Aria; Bernardo, Barbiellini; Harris, Vincent G.; Vittoria, Carmine

    2005-05-01

    The exchange constants in spinel ferrites with S-state ions, including magnesium ferrite, lithium ferrite, and manganese ferrite, were calculated using modified Becke's three-parameter density functional, where the percentage of Hartree-Fock exchange in total exchange was introduced as a variable parameter (w) to match the experimental results of exchange constants by controlling the localization and delocalization of the electrons. Consistently, the scaling factor of the 3d orbitals of ferric ions was also introduced as a variable parameter (?). From the calculation, the values of parameters w and ? matching the experimental results of JAB (nearest-neighbor exchange constant between tetrahedral and octahedral sublattices) were concentrative, while those matching the experimental results of JAA (nearest-neighbor exchange constant inside tetrahedral sublattice) and JBB (nearest-neighbor exchange constant inside octahedral sublattice) were dispersive. Observing that JAB is dominant in most practical ferrimagnetic spinel ferrites and the current accuracy of the measurements of JBB and JAA may be insufficient to support more accurate conclusion, it is suggested that there may be an empirical universal law of parameters w and ? for spinel ferrites with S-state ions.

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

    PubMed

    Nagy, Kornél; Redeuil, Karine; Rezzi, Serge

    2009-11-15

    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

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

    SciTech Connect

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

    1981-10-20

    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.

  11. Low-loss channel waveguides and Y-splitter formed by ion-exchange in silica-on-silicon.

    PubMed

    He, Zian; Li, Yigang; Li, Yingfeng; Zhang, Yanwu; Liu, Liying; Xu, Lei

    2008-03-01

    Low-loss ion-exchanged sol-gel channel waveguides on silicon substrate were fabricated. Ion-exchangeable aluminosilicate glass film was fabricated by sol-gel technique. Ag(+)-Li(+) thermal ion-exchange was used to achieve single mode channel waveguide. Propagation loss of 0.50 dB/cm and coupling loss of 0.76 dB/facet were measured by cutback method. A Y-branch power splitter was also fabricated. The results demonstrate that ion-exchange technique can be applied to prepare low-loss channel waveguides in thin film structures. PMID:18542404

  12. 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

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

    1983-01-01

    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.

  13. Measuring initial temperature through photon to dilepton ratio in heavy ion collision

    E-print Network

    Jajati K. Nayak; Jan-e Alam; Sourav Sarkar; Bikash Sinha

    2008-07-02

    Theoretical calculation of transverse momentum($p_T$) distribution of thermal photons and dileptons originating from ultra-relativistic heavy ion collisions suffer from several uncertainties since the evaluation of these spectra needs various inputs which are not yet known unambiguously. In the present work the ratio of the $p_T$ spectra of thermal photons to lepton pairs has been evaluated and it is shown that the ratio is insensitive to some of these parameters.

  14. Line ratios for helium-like ions: Applications to collision-dominated plasmas

    Microsoft Academic Search

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

    2001-01-01

    The line ratios R and G of the three main lines of He-like ions (triplet: resonance, intercombination, forbidden lines) are calculated for C V, N Vi, O Vii, Ne Ix, Mg Xi, and Si Xiii. These ratios can be used to derive electron density n_e and temperature T_e of hot late-type stellar coronae and O, B stars from high-resolution spectra

  15. Charge exchange between low energy Si ions and Cs adatoms

    NASA Astrophysics Data System (ADS)

    Chen, X.; Sroubek, Z.; Yarmoff, J. A.

    Unexpectedly large yields of positive and negative ions are produced when 2 and 5 keV Si + is singly scattered from Cs adatoms on Al(1 0 0) and Si(1 1 1). This is in contrast with Li +, in which case the ions are almost completely neutralized. The Si + ions likely result from valence electron resonant charge transfer (RCT) enhanced by promotion of the ionization level as it interacts with the Cs 5p level, but incomplete resonance neutralization of the incoming Si + cannot be absolutely excluded. The experimental data are quantitatively compared to the model and values of the microscopic parameters are estimated. Negative Si - ions are produced when the surface work function is very small, presumably by direct RCT to the projectile affinity level as it is bent downward by the image potential and by the dipole formed by the adsorbed Cs.

  16. Ion exchange determines iodine-131 concentration in aqueous samples

    NASA Technical Reports Server (NTRS)

    Fairman, W. D.; Sedlet, J.

    1967-01-01

    Inorganic radioiodide in aqueous media is analyzed by separating the radioactive iodine-131 as the iodide ion on a silver chloride column. The activity in the final precipitate may be determined by beta or gamma counting.

  17. Synthesis of polymer ion-exchange hydrogels under ? - irradiation 60Co

    NASA Astrophysics Data System (ADS)

    Le, V. M.; Zhevnyak, V. D.; Pak, V. Kh; Ananev, V. A.; Borodin, U. V.

    2015-04-01

    We have reported earlier about the modification of ion-exchange hydrogel under the influence of gamma radiation. The optimal absorbed dose of irradiation had been choosen for radiation modification of polymer hydrogels by ionits to produce products with a high content of the gel - fractions and sufficient mechanical properties. The dependence of the static exchange capacity of hydrogels on the type of ionit and its fractional composition had been studied. The dependence of the static exchange capacity of the quantitative composition of the ionit in the volume of the hydrogel had been investigated. The ion-exchange medical eye lenses had been made under selected conditions of synthesis. Their sorption properties had been studied.

  18. Ion exchange chromatography and radioimmunoassay procedure for measuring opioid peptides and substance P

    SciTech Connect

    Bergstroem, L.; Christensson, I.; Folkesson, R.; Stenstroem, B.; Terenius, L.

    1983-10-01

    The measurements of peptides of the enkephalin, dynorphin and substance P systems is complicated by the number of possible precursor fragments and degradation products that might cross-react with the antisera. By using an ion-exchanger step before radioimmunoassay one can reduce the possibility that observed peptide levels are due to precursors or metabolites. The ion-exchanger method runs with good recovery and its main advantage is that many samples can be run in parallel. The recovery from the ion-exchanger was similar using two different homogenizing media, whereas the measured endogenous levels of (Met) and (Leu)enkephalin were 3-4 fold higher with 1M acetic acid than when a 1:1 MeOH/HCl mixture was used for tissue extraction.

  19. Improved hydrous oxide ion-exchange compound catalysts

    DOEpatents

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

    1986-04-09

    Disclosed is 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 exchanged with a catalytically effective quantity of a catalyst metal, and which has been subsequently treated with a solution of a Bronsted acid.

  20. Preparation of catalysts via ion-exchangeable coatings on supports

    DOEpatents

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

    1986-04-09

    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.

  1. 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...

  2. 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...

  3. BARIUM AND RADIUM REMOVAL FROM GROUNDWATER BY ION EXCHANGE

    EPA Science Inventory

    The primary objective of this study was to determine the applicability of weak acid exchange resin in the hydrogen form for removal of hardness, barium and radium from groundwater. Weak acid resin in the hydrogen form eliminates the addition of sodium to drinking water. The capac...

  4. Application of xylenol orange to the separation of metal ions on amberlyst A-26 macroreticular anion-exchange resin.

    PubMed

    Brajter, K; Olbrych-Sleszy?ska, E

    1983-05-01

    The possibility of using a sulphonated aromatic organic complexing agent-Xylenol Orange-for separation of metal ions on the macroreticular anion-exchanger Amberlyst A-26 has been investigated. The dependence of retention on pH was determined by the batch method for Al(3+), Cr(3+), Mn(3+), Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Ga(3+), Rh(3+) Cd(2+), In(3+), Ir(3+), and Pb(2+). The selectivity differences make possible the separation of some of these metal ions. The following mixtures, of practical importance, have been separated: Al(3+)-In(3+), Ga(3+)-In(3+) Zn(2+)-In(3+), Cu(2+)-Mn(2+), in various ratios. The method has been applied to analysis of Ga-In alloy. PMID:18963372

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

    Microsoft Academic Search

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

    1995-01-01

    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

  6. Regeneration of polythionate poisoned ion exchange resin used in uranium recovery

    SciTech Connect

    Schmiedel, H.P.C.

    1984-12-04

    A process is described for the recovery of uranium from ore wherein the ore is leached, the resulting leachate is passed over an anion exchange resin, and the resin is then eluted with an elution solution containing an anion capable of replacing the uranyl anion captured on the resin, followed by treatment with a sulfite-containing solution so that polythionates captured on the ion exchange resin are reacted to form essentially thiosulfate and trithionate. Preferably, the sulfite solution also contains other anions.

  7. Copper ion-exchanged zeolite catalysts in deNO x reaction

    Microsoft Academic Search

    Hidenori Yahiro; Masakazu Iwamoto

    2001-01-01

    Copper ion-exchanged zeolites have widely been studied as the catalysts for NOx emission control. Cu-MFI zeolites, especially over-exchanged Cu-MFI, are very active for the catalytic decomposition of NO. The reaction mechanisms and the active sites suggested are summarized. The newly developed selective catalytic reduction of NO with hydrocarbons in the presence of excess oxygen is then introduced. The role of

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

    SciTech Connect

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

    1986-12-20

    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.

  9. Desalination of Saline Sludges Using Ion-Exchange Column with Zeolite

    Microsoft Academic Search

    A. E. Ghaly; M. Verma

    2008-01-01

    A flushing process followed by a zeolite based ion-exchange process were developed for the treatment of saline sludges from oil and gas exploration sites. The particle size distribution of sludge sample indicated the presence of very fine sand and clay. The electrical conductivity of the sludge was 42.2 dS m -1 indicating very saline sludge and the Cation Exchange Capacity

  10. Determination of Trace Amounts of Molybdenum in Waters with Carminic Acid by Ion-Exchange Spectrofluorimetry

    Microsoft Academic Search

    José Luis VILCHEZ; Gonzalo SÁNCHEZ-PALENCIA; Rosario BLANC; Ramiro AVIDAD; Alberto NAVALÓN

    1994-01-01

    A spectrofluorimetric method for the determination of trace amounts of molybdenum was developed, based on ion-exchange spectrofluorimetry (IEF). Molybdenum reacts with carminic acid to give a red fluorescent complex, which was fixed on a dextran-type anion-exchange gel. The fluorescence of the gel, packed on a 1-mm quartz cell, was measured directly using a solid-surface attachment. The applicable concentration range was

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

    SciTech Connect

    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

    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)

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

    SciTech Connect

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

    1996-06-01

    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.

  13. Magnetic micropatterning of FeNi/FeMn exchange bias bilayers by ion irradiation

    SciTech Connect

    Mougin, A.; Poppe, S.; Fassbender, J.; Hillebrands, B.; Faini, G.; Ebels, U.; Jung, M.; Engel, D.; Ehresmann, A.; Schmoranzer, H.

    2001-06-01

    Ion irradiation is an excellent tool to modify magnetic properties on the submicrometer scale, without modification of the sample topography. We utilize this effect to magnetically pattern exchange bias double layers using resist masks patterned by electron-beam lithography. Ion irradiation through the masks leads to a lateral modification of the magnetization reversal behavior and allows one to study the magnetization reversal as a function of the exchange bias field strength on a single sample. Results are presented on the macroscopic and microscopic magnetization reversal using the magneto-optic Kerr effect and magnetic force microscopy, respectively. {copyright} 2001 American Institute of Physics.

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

    SciTech Connect

    Nash, C.; Duignan, M.

    2010-01-14

    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.

  15. Waste treatment by ion-exchange. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    NONE

    1996-10-01

    The bibliography contains citations concerning wastewater treatment by ion-exchange techniques. Methods for removing metals, nitrates, phosphates, fluorides, and organic pollutants are described. Applications of this technology to the electroplating, metal finishing, pulp, paper, and other industries are included. The citations examine the commercial feasibility of using ion-exchange methods for pollutant reduction when the process is used alone or in combination with various pretreatment techniques. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  16. Waste treatment by ion-exchange. (Latest citations from Pollution abstracts). Published Search

    SciTech Connect

    NONE

    1995-09-01

    The bibliography contains citations concerning wastewater treatment by ion-exchange techniques. Methods for removing metals, nitrates, phosphates, fluorides, and organic pollutants are described. Applications of this technology to the electroplating, metal finishing, pulp, paper, and other industries are included. The citations examine the commercial feasibility of using ion-exchange methods for pollutant reduction when the process is used alone or in combination with various pretreatment techniques. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  17. Summary of Testing of SuperLig 639 at the TFL Ion Exchange Facility

    SciTech Connect

    Steimke, J.L.

    2000-12-19

    A pilot scale facility was designed and built in the Thermal Fluids Laboratory at the Savannah River Technology Center to test ion exchange resins for removing technetium and cesium from simulated Hanford Low Activity Waste (LAW). The facility supports the design of the Hanford River Protection Project for BNFL, Inc. The pilot scale system mimics the full-length of the columns and the operational scenario of the planned ion exchange system. Purposes of the testing include confirmation of the design, evaluation of methods for process optimization and developing methods for waste volume minimization. This report documents the performance of the technetium removal resin.

  18. Ni-Cu ion exchange observed for Ni(II)-porphyrins on Cu(111).

    PubMed

    Doyle, Catherine M; Cunniffe, John P; Krasnikov, Sergey A; Preobrajenski, Alexei B; Li, Zheshen; Sergeeva, Natalia N; Senge, Mathias O; Cafolla, Attilio A

    2014-04-01

    A Ni-Cu ion exchange has been observed for (5,15-dibromo-10,20-diphenylporphyrinato)nickel(II) (NiDBrDPP) and (5,10,15,20-tetrakis(4-bromophenyl)porphyrinato)nickel(II) (NiTBrPP) on Cu(111). The ion exchange proceeds at a faster rate for the NiDBrDPP/Cu(111) system compared to NiTBrPP/Cu(111). This is explained in terms of the macrocycle-substrate distance and the distortions that occur when the molecules are deposited on the Cu(111) surface. PMID:24548915

  19. Remark on statistical model fits to particle ratios in relativistic heavy ion collisions

    E-print Network

    F. Becattini

    2007-09-14

    In order to determine the chemical freeze-out parameters of the hadron-emitting source in relativistic heavy ion collisions some studies in literature perform fits by using as data input a subsample of ratios calculated out of experimentally measured hadron yields instead of yields themselves. We show that this is a statistically incorrect method fit, implying a bias in the extracted parameters.

  20. Nuclear quantum effects in water exchange around lithium and fluoride ions

    E-print Network

    Wilkins, David M; Dang, Liem X

    2015-01-01

    We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the exchange processes are unaffected by quantization, so a classical description of these reaction...

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

    SciTech Connect

    Jacob Espinoza; Mary Barr; Wayne Smith

    1998-12-01

    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.

  2. Evaluation of Ion Specific Heat Ratio in a Transonic Plasma Flow

    NASA Astrophysics Data System (ADS)

    Ando, Akira; Inutake, Masaaki; Hattori, Kunihiko; Makita, Takahiro; Isobe, Hirokazu

    2006-10-01

    Dynamics of a fast-flowing plasma in a magnetic field are important to clarify a variety of MHD phenomena in space-, fusion- and also in electric propulsion-plasmas. Although an ion specific heat ratio ?i is one of the key parameters in plasma dynamic behaviors, it has not been measured yet in laboratory plasmas. In a high density plasma with a weak magnetic field, electrons are magnetized and restricted by a magnetic field, besides ions are not magnetized and behaves as ion fluid surrounded by the field-restricted electrons. In this case, ion Mach number changes according to the one-dimensional (1D) isentropic flow model. When a compressible flow passes through a Laval nozzle, Mach number becomes unity at the nozzle throat. We measured an ion Mach number Mi by a Mach probe in a transonic plasma flow passing through a Laval type magnetic nozzle. The ion specific heat ratio ?i was evaluated for the first time by comparing the spatial profile of Mi with 1D flow model.

  3. Human cytoplasmic copper chaperones Atox1 and CCS exchange copper ions in vitro.

    PubMed

    Petzoldt, Svenja; Kahra, Dana; Kovermann, Michael; Dingeldein, Artur Pg; Niemiec, Moritz S; Ådén, Jörgen; Wittung-Stafshede, Pernilla

    2015-06-01

    After Ctr1-mediated copper ion (Cu) entry into the human cytoplasm, chaperones Atox1 and CCS deliver Cu to P1B-type ATPases and to superoxide dismutase, respectively, via direct protein-protein interactions. Although the two Cu chaperones are presumed to work along independent pathways, we here assessed cross-reactivity between Atox1 and the first domain of CCS (CCS1) using biochemical and biophysical methods in vitro. By NMR we show that CCS1 is monomeric although it elutes differently from Atox1 in size exclusion chromatography (SEC). This property allows separation of Atox1 and CCS1 by SEC and, combined with the 254/280 nm ratio as an indicator of Cu loading, we demonstrate that Cu can be transferred from one protein to the other. Cu exchange also occurs with full-length CCS and, as expected, the interaction involves the metal binding sites since mutation of Cu-binding cysteine in Atox1 eliminates Cu transfer from CCS1. Cross-reactivity between CCS and Atox1 may aid in regulation of Cu distribution in the cytoplasm. PMID:25673218

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

    Microsoft Academic Search

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

    1996-01-01

    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

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

    SciTech Connect

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

    1986-05-10

    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.

  6. In vivo and in vitro measurements of complex-type chromosomal exchanges induced by heavy ions

    Microsoft Academic Search

    K. George; M. Durante; H. Wu; V. Willingham; F. A Cucinotta

    2003-01-01

    Heavy ions are more efficient in producing complex-type chromosome exchanges than sparsely ionizing radiation, and this can potentially be used as a biomarker of radiation quality. We measured the induction of complex-type chromosomal aberrations in human peripheral blood lymphocytes exposed in vitro to accelerated H-, He-, C-, Ar-, Fe- and Au-ions in the LET range of approximately 4–1400 keV\\/?m Chromosomes

  7. In Vivo and in Vitro measurements of complex-type chromosomal exchanges induced by heavy ions

    Microsoft Academic Search

    K. George; M. Durante; H. Wu; V. Winllingham; F. Cucinotta

    2002-01-01

    Heavy ions are more efficient in producing complex-type chromosome exchanges than sparsely ionizing radiation, and this can potentially be used as a biomarker of radiation quality. We measured the induction of complex-type chromosomal aberrations in human peripheral blood lymphocytes exposed in vitro to accelerated H-, He-, C-, Si-, Ar-, Fe- and Au-ions in the LET range 0.4-1400 keV\\/mum. Chromosomes were

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

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

    SciTech Connect

    Hong, Jinhy; Min, Kyoungwook [Department of Physics, KAIST, Daejeon 305-701 (Korea, Republic of); Lee, Ensang [School of Space Research, Kyung Hee University, Yongin, Gyeonggi 446-701 (Korea, Republic of); Parks, George K. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)

    2012-09-15

    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.

  10. 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...

  11. Pectin based cerium (IV) and thorium (IV) phosphates as novel hybrid fibrous ion exchangers synthesis, characterization and thermal behaviour

    Microsoft Academic Search

    K. G. Varshney; A. Agrawal; S. C. Mojumdar

    2005-01-01

    Summary Pectin based cerium (IV) and thorium (IV) phosphates have been synthesized as new phases of hybrid fibrous ion exchangers. Both materials were characterized using X-ray diffraction, infrared (IR) spectra, thermogravimetric analysis (TG), differntial thermogravimetry (DTG), differntial thermal analysis (DTA) and scanning electron microscopy (SEM), as well as the determination of their ion exchange capacity, elution and pH titration. The

  12. CHROMATE AND COPPER ADSORPTION BY DUAL-FUNCTIONAL ION EXCHANGE RESINS MADE FROM AGRICULTURAL BY-PRODUCTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ion exchange resins commonly have a single functionality for either cations or anions. Resins that have a dual functionality for both cations and anions are uncommon. The objective of this study was to create dual-functional ion exchange resins derived from soybean hulls, sugarcane bagasse and cor...

  13. Recovering gold from thiosulfate leach pulps via ion exchange

    NASA Astrophysics Data System (ADS)

    Nicol, Michael J.; O'Malley, Glen

    2002-10-01

    Increasing environmental and occupational safety concerns about the use of cyanide in gold processing has increased interest in more acceptable alternative lixiviants, the most promising of which is thiosulfate. However, the thiosulfate process lacks a proven inpulp method of recovering the dissolved gold because activated carbon is not effective for the absorption of the gold-thiosulfate complex. This paper describes work aimed at evaluating the effectiveness of commercially available anion exchange resins for the recovery of gold from thiosulfate leach liquors and pulps.

  14. Self-consistent Equilibrium Model of Low-aspect-ratio Toroidal Plasma with Energetic Beam Ions

    SciTech Connect

    E.V. Belova; N.N. Gorelenkov; C.Z. Cheng

    2003-04-09

    A theoretical model is developed which allows the self-consistent inclusion of the effects of energetic beam ions in equilibrium calculations of low-aspect-ratio toroidal devices. A two-component plasma is considered, where the energetic ions are treated using a kinetic Vlasov description, while a one-fluid magnetohydrodynamic description is used to represent the thermal plasma. The model allows for an anisotropic distribution function and a large Larmor radius of the beam ions. Numerical results are obtained for neutral-beam-heated plasmas in the National Spherical Torus Experiment (NSTX). Self-consistent equilibria with an anisotropic fast-ion distribution have been calculated for NSTX. It is shown for typical experimental parameters that the contribution of the energetic neutral-beam ions to the total current can be comparable to that of the background plasma, and that the kinetic modifications of the equilibrium can be significant. The range of validity of the finite-Larmor-radius expansion and of the reduced kinetic descriptions for the beam ions in NSTX is discussed. The calculated kinetic equilibria can be used for self-consistent numerical studies of beam-ion-driven instabilities in NSTX.

  15. Evaluation of Selective Ion Exchange Resins for Removal of Mercury from the H-Area Water Treatment Unit

    SciTech Connect

    Serkiz, S.M.

    2000-09-05

    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.

  16. Measuring surface-area-to-volume ratios in soft porous materials using laser-polarized xenon interphase exchange NMR

    E-print Network

    J. P. Butler; R. W. Mair; S. Patz; D. Hoffmann; M. I. Hrovat; R. A. Rogers; G. P. Topulos; R. L. Walsworth

    2001-08-21

    We demonstrate a minimally invasive nuclear magnetic resonance (NMR) technique that enables determination of the surface-area-to-volume ratio (S/V) of soft porous materials from measurements of the diffusive exchange of laser-polarized 129Xe between gas in the pore space and 129Xe dissolved in the solid phase. We apply this NMR technique to porous polymer samples and find approximate agreement with destructive stereological measurements of S/V obtained with optical confocal microscopy. Potential applications of laser-polarized xenon interphase exchange NMR include measurements of in vivo lung function in humans and characterization of gas chromatography columns.

  17. Exploring the favorable ion-exchange ability of phthalylated cellulose biopolymer using thermodynamic data.

    PubMed

    de Melo, Júlio C P; da Silva Filho, Edson C; Santana, Sirlane A A; Airoldi, Claudio

    2010-09-01

    A phthalylated ion-exchange biopolymer was obtained by adding cellulose to molten phthalic anhydride in a quasi solvent-free procedure. Through this route 2.99+/-0.07 mmolg(-1) of pendant groups containing ester and carboxylic acid moieties were incorporated into the polymeric structure that was characterized by elemental analysis, solid-state carbon nuclear magnetic resonance (CP/MAS), infrared spectroscopy, X-ray diffraction, and thermogravimetry. The chemically modified polysaccharide is able to exchange cations from aqueous solution as demonstrated by batchwise methodology. The data were adjusted to a modified Langmuir equation to give 2.43+/-0.12 and 2.26+/-0.11 mmolg(-1) for divalent cobalt and nickel cations, respectively. The net thermal effects obtained from calorimetric titration measurements were also adjusted to a modified Langmuir equation, and the enthalpy of the interaction was calculated to give endothermic values of 2.11+/-0.28 and 2.50+/-0.31kJmol(-1) for these cations, respectively. The spontaneity of this ion-exchange process is reflected in negative Gibbs energy and with a contribution of positive entropic values. This set of thermodynamic data at the solid-liquid interface suggests a favorable ion-exchange process for this anchored biopolymer for cation exchange from the environment. PMID:20673881

  18. Phosphorus Recovery From Urban Wastewater Treatment Plant Sludge Liquor by Ion Exchange

    Microsoft Academic Search

    A. Bottini; L. Rizzo

    2012-01-01

    In this study phosphorous recovery from sludge liquor by ion exchange process was investigated. The efficiency of a commercially available anionic iron oxide resin was evaluated in batch and packed column tests using synthetic phosphorous solution and actual sludge liquor, taken from of an urban wastewater treatment plant (UWWTP). When phosphorous recovery from sludge liquor was investigated, experimental data fitted

  19. Highly-selective and Regenerable Ion Exchange for Perchlorate Remediation, Recovery, and Environmental Forensics

    NASA Astrophysics Data System (ADS)

    Gu, B.; Brown, G.

    2007-12-01

    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.

  20. 1×4 buried optical power splitter fabricated by Tl^(+)-Na^(+) ion-exchange

    NASA Astrophysics Data System (ADS)

    Zhou, Zigang; Liu, Desen

    2003-11-01

    A new 1×4 buried optical power splitter with curved Y-junction structure has been successfully designed by a beam propagation method (BPM) software and fabricated by two-step ion-exchange in glass. The optical qualities of the device are favorable in comparison with that obtained with dry etching fabrication techniques.

  1. High-resolution determination of {sup 147}Pm in urine using dynamic ion-exchange chromatography

    SciTech Connect

    Elchuk, S.; Lucy, C.A.; Burns, K.I. [Chalk River Labs., Ontario (Canada)

    1992-10-15

    Ion exchange preconcentration followed by HPLC purification prior to scintillation counting was used to measure the concentration of {sup 147}Pm in urine. the detection limit for this method was found to be 0.1 Bq (3 fg) of {sup 147}Pm in 500 ml of urine.

  2. Development and testing of ion exchangers for treatment of liquid wastes at Oak Ridge National Laboratory

    SciTech Connect

    Collins, J.L.; Davidson, D.J.; Chase, C.W.; Egan, B.Z. (Oak Ridge National Lab., TN (United States)); Ensor, D.D.; Bright, R.M.; Glasgow, D.C. (Tennessee Technological Univ., Cookeville, TN (United States))

    1993-03-01

    This report addresses three areas of waste treatment: (1) treatment of newly generated low-level liquid waste and Melton Valley Storage Tank (MVST) supernate using inorganic ion exchangers; (2) treatment of processing streams at the Radiochemical Engineering Development Center (REDC); and (3) removal of radionuclides from organic solutions. Distribution of various radionuclides between simulated waste solutions and several sorbents was determined in batch tests. Inorganic ion exchangers were prepared in the form of microspheres by an intemal gelation process. Microspheres of hydrous titania, hydrous zirconia, hydrous titania containing embedded sodium cobalt hexacyanoferrate, and the corresponding phosphate forms of these materials were prepared. Several zeolites (PDZ-140, PDZ-300, EE-96, CBV-10A) and inorganic ion exchangers (hydrous titania, hydrous zirconia, polyantimanic acid, sodium cobalt hexacyanoferrate) were tested for the removal of cesium and strontium from the acidic simulated Cleanex raffinate generated at REDC. A resorcinol-based ion-exchange resin and three types of sodium titanate were tested for removal of cesium and strontium from the REDC caustic dissolver solution. Hydrous titania, hydrous zirconia, and their corresponding phosphates were tested for the removal of Eu[sup 3+] from various solutions of di-2-ethylbexyl phosphoric acid (HDEHP) in toluene or dodecane.

  3. Development and testing of ion exchangers for treatment of liquid wastes at Oak Ridge National Laboratory

    SciTech Connect

    Collins, J.L.; Davidson, D.J.; Chase, C.W.; Egan, B.Z. [Oak Ridge National Lab., TN (United States); Ensor, D.D.; Bright, R.M.; Glasgow, D.C. [Tennessee Technological Univ., Cookeville, TN (United States)

    1993-03-01

    This report addresses three areas of waste treatment: (1) treatment of newly generated low-level liquid waste and Melton Valley Storage Tank (MVST) supernate using inorganic ion exchangers; (2) treatment of processing streams at the Radiochemical Engineering Development Center (REDC); and (3) removal of radionuclides from organic solutions. Distribution of various radionuclides between simulated waste solutions and several sorbents was determined in batch tests. Inorganic ion exchangers were prepared in the form of microspheres by an intemal gelation process. Microspheres of hydrous titania, hydrous zirconia, hydrous titania containing embedded sodium cobalt hexacyanoferrate, and the corresponding phosphate forms of these materials were prepared. Several zeolites (PDZ-140, PDZ-300, EE-96, CBV-10A) and inorganic ion exchangers (hydrous titania, hydrous zirconia, polyantimanic acid, sodium cobalt hexacyanoferrate) were tested for the removal of cesium and strontium from the acidic simulated Cleanex raffinate generated at REDC. A resorcinol-based ion-exchange resin and three types of sodium titanate were tested for removal of cesium and strontium from the REDC caustic dissolver solution. Hydrous titania, hydrous zirconia, and their corresponding phosphates were tested for the removal of Eu{sup 3+} from various solutions of di-2-ethylbexyl phosphoric acid (HDEHP) in toluene or dodecane.

  4. 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...

  5. Electro-osmosis of the second kind near the heterogeneous ion-exchange membrane

    Microsoft Academic Search

    N. A. Mishchuk

    1998-01-01

    The features of concentrated polarization by an electric current passing through an ion-exchange membrane, with heterogeneous ionic conductivity, are considered in this paper. A space charge appears inside the concentrated polarization zone caused by a strong electric field. In the case of a surface with nonuniform conductivity, the tangential to the surface component of electric field occurs. The action of

  6. Novel integrated polarization analyzer sensor made by ion-exchange in glass

    Microsoft Academic Search

    Pierre Lemaître-Auger; Khelifa Djerroud; Philippe Benech; Pierre Benech

    2006-01-01

    In this paper, we propose a novel integrated polarization analyzer sensor (IPAS) made by ion exchange on a glass substrate. It is capable to determine the polarization state of a light beam: elliptical, circular or linear. Furthermore, in the first case, the sensor measures the ellipse's eccentricity and the angle between its major axis and the x-axis of the IPAS

  7. Dose consequence analysis for transporting Plutonium Recycle Test Reactor (PRTR) rupture loop ion exchange columns

    SciTech Connect

    Goldberg, H.J., Westinghouse Hanford

    1996-07-03

    Ion exchange columns from the 309 Plutonium Recycle Test Reactor rupture loop must be shipped to the solid waste burial ground. The enclosed calculational note documents the calculations used to calculate the absorbed doses expected in the case of a postulated accident.

  8. Extraction of phosphorus, potassium, calcium, and magnesium from soils by an ion?exchange resin procedure

    Microsoft Academic Search

    B. van Raij; J. A. Quaggio; N. M. da Silva

    1986-01-01

    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

  9. Ion exchange behavior among metal trisilicates: probing selectivity, structures, and mechanism 

    E-print Network

    Fewox, Christopher Sean

    2008-10-10

    One model system for the investigation of selectivity in inorganic ion exchangers is a group of synthetic analogues of the mineral umbite. Hydrothermally synthesized trisilicates with the general form A2BSi3O9.H2O, where A is a monovalent cation...

  10. Ultrafine sodium titanate nanowires with extraordinary sr ion-exchange properties.

    PubMed

    Ishikawa, Yoshifumi; Tsukimoto, Susumu; Nakayama, Koji S; Asao, Naoki

    2015-05-13

    Ultrafine sodium titanate nanowires are produced from TiAl alloy precursors via a nonthermal process where Al leaching and Ti oxidation occur simultaneously in an alkaline medium. The obtained nanowires demonstrate a layered crystal structure with a diameter of a few nanometers and exhibit remarkable Sr ion-exchange properties. PMID:25872867

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

    Microsoft Academic Search

    Kimberly E. Carter; James Farrell

    2010-01-01

    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

  12. Contamination of Surfaces by Conductivity Water from Ion-exchange Resins

    Microsoft Academic Search

    J. H. Schenkel; J. A. Kitchener

    1958-01-01

    IN several recent papers research workers in surface chemistry have reported using ion-exchange resins as a convenient means of removing electrolytes-in place of dialysis in the treatment of inorganic sols, for example, and to obtain `conductivity water' for studies of dilute detergent solutions or monolayers on a Langmuir trough. For most purposes where `pure' water is needed, even in colloid

  13. Exchange and polarization effects on elastic electron-atom/ion scattering

    E-print Network

    Kaganovich, Igor

    Exchange and polarization effects on elastic electron-atom/ion scattering (aka. a small part approaches Needed for modeling and simulations : · accurate atomic and molecular data (, d/d, , rates physics · atomic physics · molecular physics · beam-surface interactions #12;0 ( ) ( ) ( ) ( ) e e e i i i

  14. Selective stripping voltammetric determinations employing cells for electrolysis with simultaneous ion-exchange or solvent extraction.

    PubMed

    Stulík, K; Bedros, P

    1976-08-01

    Cells have been designed for stripping-voltammetry analyses employing graphite working electrodes and mercury film electrodes on a graphite support, permitting ion-exchange or solvent extraction separation simultaneously with the pre-electrolysis. The ion-exchange separation was tested on the determination of mercury in the presence of excess of copper(II), lead and cadmium and on the determination of bismuth in the presence of excess of copper(II). The solvent extraction separation was tested on the determination of mercury(II) in the presence of copper(II), lead and cadmium and the determination of copper(II) in the presence of bismuth. Very good results were obtained by using ion-exchange, where the sensitivity and precision of the determination are comparable with those obtained in the determinations without separation, the separation efficiency being very high, limited virtually only by the capacity of the ion-exchanger used. The solvent extraction separations yielded poorer results: the sensitivity of the determination is decreased substantially, the separation efficiency is not very high and difficulties arise from the adsorption of the organic phase on the electrode surface. PMID:18961929

  15. Cement waste-form development for ion-exchange resins at the Rocky Flats Plant

    Microsoft Academic Search

    G. W. Veazey; R. L. Ames

    1997-01-01

    This report describes the development of a cement waste form to stabilize ion-exchange resins at Rocky Flats Environmental Technology Site (RFETS). These resins have an elevated potential for ignition due to inadequate wetness and contact with nitrates. The work focused on the preparation and performance evaluation of several Portland cement\\/resin formulations. The performance standards were chosen to address Waste Isolation

  16. 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...

  17. Modelling of the chromatographic separation of xylose-mannose in ion-exchange resin columns

    Microsoft Academic Search

    A. M. Wilhelm; G. Casamatta; T. Carillon; L. Rigal; A. Gaset

    1989-01-01

    A mathematical model was proposed for the chromatographic separation of xylose and mannose on an ion-exchange resin in the Pb form: dispersion in the mobile phase, external mass transfer around the particles and internal diffusion were taken into account. Small-scale experiments provided an evaluation of the different parameters. Dispersion in the mobile phase was found to be the predominant phenomenon.

  18. Microscale separation of mixtures of acids using ion-exchange resins

    Microsoft Academic Search

    G. J. Lawson; J. W. Purdie

    1961-01-01

    Summary Mixtures of carboxylic acids, containing about 200µg of each, may be fractionated by gradient elution from micro-columns of ion-exchange resins. The fractions are collected successively on filter paper and further separated by paper chromatography. Using this method the components of a mixture of twelve acids were readily identified.

  19. PURIFICATION AND CONCENTRATION OF URANIUM IN RIVER WATER USING AN ION EXCHANGE RESIN

    Microsoft Academic Search

    R. E. Shoaf; H. L. Galloway; F. S. Voss

    1956-01-01

    An analytical method is presented for the determination of uranium in ; river water containing a high solid content. The uranium is concentrated and ; purified by adsorption of the uranyl sulfate ion on an union exchange resin, ; followed by elution with a small amount of nitric acid solution. The purified ; uranium is then determined fluorimetricelly. This method

  20. The recovery of gold from ammoniacal thiosulfate solutions containing copper using ion exchange resin columns

    Microsoft Academic Search

    Hongguang Zhang; David B Dreisinger

    2004-01-01

    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.

  1. Selective elution of copper and iron cyanide complexes from ion exchange resins using saline solutions

    Microsoft Academic Search

    G. C Lukey; J. S. J van Deventer; D. C Shallcross

    2000-01-01

    Numerous reagents for the elution of metal cyanide complexes from ion exchange resins have been proposed previously. However, a simple and cost-effective elution procedure has not been developed that is able to selectively strip metal cyanide complexes from the resin. The results of the current study show that highly saline solutions can be used to selectively elute copper cyanide and

  2. IMPROVEMENTS IN METHODS FOR THE ALKALINE TREATMENT OF URANIUM ORES BY MEANS OF ION EXCHANGE RESINS

    Microsoft Academic Search

    P. Mouret; B. Parly; P. Pottier

    1962-01-01

    After crushing, uranium ore is subjected to an alkaline leach. An ion ; exchange resin is employed to adsorb uranium from the resulting solution. ; Elution of the saturated base follows, the uranium being precipitated from the ; eluate by treatment with a base. (R.J.S.)

  3. Prediction of ion-exchange column breakthrough curves by constant-pattern wave approach.

    PubMed

    Lee, I-Hsien; Kuan, Yu-Chung; Chern, Jia-Ming

    2008-03-21

    The release of heavy metals from industrial wastewaters represents one of major threats to environment. Compared with chemical precipitation method, fixed-bed ion-exchange process can effectively remove heavy metals from wastewaters and generate no hazardous sludge. In order to design and operate fixed-bed ion-exchange processes successfully, it is very important to understand the column dynamics. In this study, the column experiments for Cu2+/H+, Zn2+/H+, and Cd2+/H+ systems using Amberlite IR-120 were performed to measure the breakthrough curves under varying operating conditions. The experimental results showed that total cation concentration in the mobile-phase played a key role on the breakthrough curves; a higher feed concentration resulted in an earlier breakthrough. Furthermore, the column dynamics was also predicted by self-sharpening and constant-pattern wave models. The self-sharpening wave model assuming local ion-exchange equilibrium could provide a simple and quick estimation for the breakthrough volume, but the predicted breakthrough curves did not match the experimental data very well. On the contrary, the constant-pattern wave model using a constant driving force model for finite ion-exchange rate provided a better fit to the experimental data. The obtained liquid-phase mass transfer coefficient was correlated to the flow velocity and other operating parameters; the breakthrough curves under varying operating conditions could thus be predicted by the constant-pattern wave model using the correlation. PMID:17686577

  4. Drug release from ion-exchange microspheres: mathematical modeling and experimental verification.

    PubMed

    Abdekhodaie, Mohammad J; Wu, Xiao Yu

    2008-04-01

    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

  5. Tank 241-AZ-102 SuperLig 639 Technetium Ion Exchange Eluate Evaporation Study

    Microsoft Academic Search

    2001-01-01

    As part of the Hanford River Protection Project (RPP), the Savannah River Technology Center (SRTC) has conducted tests on the pretreatment and vitrification of a radioactive waste sample from Hanford Tank 241-AZ-102. The original, AZ-102 sample which was received at SRTC was characterized and filtered to remove entrained solids.1 The sample was then passed sequentially through ion exchange columns containing

  6. 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 ...

  7. Hybridization of III-V semiconductor membranes onto ion-exchanged waveguides

    Microsoft Academic Search

    Matthieu Nannini; Etienne Grondin; Arnaud Gorin; Vincent Aimez; Jean-Emmanuel Broquin

    2005-01-01

    In this paper, we present an original method for the realization of hybrid photonic integrated circuits (PICs) based on ion-exchanged (IE) waveguides and III-V semiconductor materials. In our approach, we propose to bond thin semiconductor membranes at designated locations of the PIC where active functions are required. The advantage of very thin membranes is the possibility to keep the optical

  8. Effect of duty ratio of patterned surface on planarization by gas cluster ion beams

    NASA Astrophysics Data System (ADS)

    Nagato, Keisuke; Toyoda, Noriaki; Naito, Hiroki; Tani, Hiroshi; Sakane, Yasuo; Yamada, Isao; Nakao, Masayuki; Hamaguchi, Tetsuya

    2011-04-01

    We studied the effect of the duty ratio, i.e., the ratio of hill width to pitch, of patterned diamondlike carbon (DLC) surfaces on Ar gas cluster ion beam (GCIB) planarization effect. The patterns of 40 nm depth were fabricated on Si substrates by electron beam lithography and CHF3 reactive-ion etching. The pitch of the line-and-space pattern was 300 nm and three duty ratios were adopted. Then, refilling materials were deposited to 50 nm thickness on the patterned substrates. The test samples were irradiated by Ar-GCIB and the resultant surface profiles were measured by atomic force microscopy. The acceleration energy for one cluster was 20 keV. The dose was set in the range from 5×1014 to 5×1016 ion/cm2. Although there was a difference in the dose, the patterns clearly disappeared upon irradiating GCIB. The reduction rate of the peak-to-valley height decreased as the width of the hill increased. We indicated that GCIB irradiation is effective for the planarization of patterned surfaces with various duty ratios.

  9. Magnetic ion-exchange nanoparticles and their application in proton exchange membranes

    Microsoft Academic Search

    Smita B. Brijmohan; Montgomery T. Shaw

    2007-01-01

    Nanoparticles with dual properties of magnetic susceptibility and ionic conductivity were synthesized for application in proton exchange membranes (PEM). The particles were composite in nature, consisting of ?-Fe2O3 and sulfonated crosslinked polystyrene. The synthesis was carried out using emulsion polymerization with various feed compositions ranging from 0 to 23wt% ionic monomer and 8–11wt% crosslinking monomer. The synthesized particles were in

  10. Natural clinoptilolite as an exchanger of Ni 2+ and NH 4 + ions under hydrothermal conditions and high ammonia concentration

    Microsoft Academic Search

    Inocente Rodr??guez-Iznaga; Ariel Gómez; Gerardo Rodr??guez-Fuentes; Adelaida Ben??tez-Aguilar; Juan Serrano-Ballan

    2002-01-01

    Natural clinoptilolite from Caimanes deposit (Moa-Cuba) has been used for the nickel removal from aqueous solution by ion exchange. The Ni2+ elution, using ammonia-rich solution, has been also studied in form of a nickel removal–elution ion-exchange cyclic process. The stability of clinoptilolite as an exchanger of Ni2+ and NH4+ cations under hydrothermal conditions and high ammonia concentrations is analyzed. No

  11. Nanometer scale high-aspect-ratio trench etching at controllable angles using ballistic reactive ion etching

    SciTech Connect

    Cybart, Shane; Roediger, Peter; Ulin-Avila, Erick; Wu, Stephen; Wong, Travis; Dynes, Robert

    2012-11-30

    We demonstrate a low pressure reactive ion etching process capable of patterning nanometer scale angled sidewalls and three dimensional structures in photoresist. At low pressure the plasma has a large dark space region where the etchant ions have very large highly-directional mean free paths. Mounting the sample entirely within this dark space allows for etching at angles relative to the cathode with minimal undercutting, resulting in high-aspect ratio nanometer scale angled features. By reversing the initial angle and performing a second etch we create three-dimensional mask profiles.

  12. Dissociative recombination of water cluster ions with free electrons: cross sections and branching ratios.

    PubMed

    Ojekull, J; Andersson, P U; Pettersson, J B C; Markovi?, N; Thomas, R D; Al Khalili, A; Ehlerding, A; Osterdahl, F; af Ugglas, M; Larsson, M; Danared, H; Källberg, A

    2008-01-28

    Dissociative recombination (DR) of water cluster ions H(+)(H(2)O)(n) (n=4-6) with free electrons has been studied at the heavy-ion storage ring CRYRING (Manne Siegbahn Laboratory, Stockholm University). For the first time, branching ratios have been determined for the dominating product channels and absolute DR cross sections have been measured in the energy range from 0.001 to 0.7 eV. Dissociative recombination is concluded to result in extensive fragmentation for all three cluster ions, and a maximum number of heavy oxygen-containing fragments is produced with a probability close to unity. The branching ratio results agree with earlier DR studies of smaller water cluster ions where the channel nH(2)O+H has been observed to dominate and where energy transfer to internal degrees of freedom has been concluded to be highly efficient. The absolute DR cross sections for H(+)(H(2)O)(n) (n=4-6) decrease monotonically with increasing energy with an energy dependence close to E(-1) in the lower part of the energy range and a faster falloff at higher energies, in agreement with the behavior of other studied heavy ions. The cross section data have been used to calculate DR rate coefficients in the temperature range of 10-2000 K. The results from storage ring experiments with water cluster ions are concluded to partly confirm the earlier results from afterglow experiments. The DR rate coefficients for H(+)(H(2)O)(n) (n=1-6) are in general somewhat lower than reported from afterglow experiments. The rate coefficient tends to increase with increasing cluster size, but not in the monotonic way that has been reported from afterglow experiments. The needs for further experimental studies and for theoretical models that can be used to predict the DR rate of polyatomic ions are discussed. PMID:18247953

  13. Electrosorptive desalination by carbon nanotubes and nanofibres electrodes and ion-exchange membranes.

    PubMed

    Li, Haibo; Gao, Yang; Pan, Likun; Zhang, Yanping; Chen, Yiwei; Sun, Zhuo

    2008-12-01

    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

  14. Ion exchange membranes as novel passive sampling material for organic ions: application for the determination of freely dissolved concentrations.

    PubMed

    Oemisch, Luise; Goss, Kai-Uwe; Endo, Satoshi

    2014-11-28

    Many studies in pharmacology, toxicology and environmental science require a method for determining the freely dissolved concentration of a target substance. A recently developed tool for this purpose is equilibrium passive sampling with polymeric materials. However, this method has rarely been applied to ionic organic substances, primarily due to limited availability of convenient sorption materials. This study introduces ion exchange membranes (IEMs) as a novel passive sampling material for organic ions. The partitioning of 4-ethylbenzene-1-sulfonate, 2,4-dichlorophenoxyacetic acid and pentachlorophenol to one anion exchange membrane (FAS) and of difenzoquat, nicotine and verapamil to one cation exchange membrane (FKS) was investigated. All test substances exhibited a sufficiently high affinity for the respective IEM with logarithmic IEM-water partition coefficients >2.3. Sorption equilibrium was established quickly, within several hours for the FAS membrane and within 1-3 days for the FKS membrane. For permanently charged substances the partitioning to the IEMs was independent of pH, but was influenced by the salt composition of the test solution. For all test substances sorption to IEM was dependent on the substance concentration. Bovine serum albumin-water partition coefficients determined by passive sampling with IEMs agree well with those determined by the conventional dialysis method. The results of this study indicate that IEMs exhibit the potential to measure freely dissolved concentrations of organic ions in a simple and time-saving manner. PMID:25454126

  15. High aspect ratio micro- and nano-machining of silicon using time-multiplexed reactive ion etching

    Microsoft Academic Search

    Z Sanaee; M Poudineh; M Abdolahad; S Mohajerzadeh

    2011-01-01

    A low-density plasma reactive ion etching is reported to realize high aspect ratio silicon nanorods on silicon substrates. Aspect ratios with values more than 100 are obtained for features below 200 nm. The process uses a mixture of three gases of hexaflourosulfide, hydrogen and oxygen in a reactive ion etching system with a programmed passivation and etching sub-cycles. Using these

  16. Study of Flux Ratio of C60 to Ar Cluster Ion for Hard DLC Film deposition

    SciTech Connect

    Miyauchi, K.; Toyoda, N.; Kanda, K.; Matsui, S. [Lab. of adv. science and tech. for industry, Himeji Iinst. of Tech., Ako-gun, Hyogo (Japan); Kitagawa, T. [Lab. of adv. science and tech. for industry, Himeji Iinst. of Tech., Ako-gun, Hyogo (Japan); Nomura Plating Co., Ltd., Nishiyodogawa, Osaka (Japan); Yamada, I. [Lab. of adv. science and tech. for industry, Himeji Iinst. of Tech., Ako-gun, Hyogo (Japan); Collaborative research center for cluster ion beam process technology (Japan)

    2003-08-26

    To study the influence of the flux ratio of C60 molecule to Ar cluster ion on (diamond like carbon) DLC film characteristics, DLC films deposited under various flux ratios were characterized with Raman spectrometry and Near Edge X-ray Absorption Fine Structure (NEXAFS). From results of these measurements, hard DLC films were deposited when the flux ratio of C60 to Ar cluster ion was between 0.7 and 4. Furthermore the DLC film with constant sp2 content was obtained in the range of the ratio from 0.7 to 4, which contents are lower values than that of conventional films such as RF plasma. DLC films deposited under the ratio from 1 to 4 had hardness from 40 to 45GPa. It was shown that DLC films with stable properties of low sp2 content and high hardness were formed even when the fluxes were varied from 1 to 4 during deposition. It was indicated that this process was useful in the view of industrial application.

  17. Ion exchange membranes as electrolyte to improve high temperature capacity retention of LiMn2O4 cathode lithium-ion batteries.

    PubMed

    Liu, Yanbo; Tan, Lei; Li, Lei

    2012-10-11

    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

  18. Forward and reverse ion-exchange kinetics for some alkali and alkaline earth metal ions on amorphous zirconium(IV) aluminophosphate

    SciTech Connect

    Varshney, K.G.; Pandith, A.H.

    1999-10-26

    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.

  19. Ion exchange columns for selective removal of cesium from aqueous radioactive waste using hydrous crystalline silico-titanates 

    E-print Network

    Ricci, David Michael

    1995-01-01

    conscious society. In Hanford, WA, hundreds of underground storage tanks hold tens of millions of gallons of aqueous radioactive waste. This liquid waste, which has a very high sodium content, contains trace amounts of radioactive cesium 137. Since... limitations, especially concerning the Hanford waste solution. Calmon (1979) points out that a major limitation with most ion exchangers is that they remove undesirable ions as well as target ions, the exchanger reaches total capacity quicker. In the case...

  20. Two-magnon Raman scattering in spin-ladder geometries and the ratio of rung and leg exchange constants

    NASA Astrophysics Data System (ADS)

    Freitas, P. J.; Singh, R. R. P.

    2000-12-01

    We discuss ways in which the ratio of exchange constants along the rungs and legs of a spin-ladder material influences the two-magnon Raman scattering spectra and hence can be determined from it. We show that within the Fleury-Loudon-Elliott approach, the Raman line shape does not change with polarization geometries. This line shape is well known to be difficult to calculate accurately from theory. However, the Raman scattering intensities do vary with polarization geometries, which are easy to calculate. With some assumptions about the Raman scattering Hamiltonian, the latter can be used to estimate the ratio of exchange constants. We apply these results to the recent measurements of Sugai et al. of Raman scattering from spin-ladder materials such as La6Ca8Cu24O41 and Sr14Cu24O41.

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

    PubMed

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

    2014-03-01

    We report single-crystal X-band EPR and magnetic measurements of the coordination polymer catena-(trans-(?2-fumarato)tetraaquacobalt(II)), 1, and the Co(II)-doped Zn(II) analogue, 2, in different Zn:Co ratios. 1 presents two magnetically inequivalent high spin S = 3/2 Co(II) ions per unit cell, named A and B, in a distorted octahedral environment coordinated to four water oxygen atoms and trans coordinated to two carboxylic oxygen atoms from the fumarate anions, in which the Co(II) ions are linked by hydrogen bonds and fumarate molecules. Magnetic susceptibility and magnetization measurements of 1 indicate weak antiferromagnetic exchange interactions between the S = 3/2 spins of the Co(II) ions in the crystal lattice. Oriented single crystal EPR experiments of 1 and 2 were used to evaluate the molecular g-tensor and the different exchange coupling constants between the Co(II) ions, assuming an effective spin S?= 1/2. Unexpectedly, the eigenvectors of the molecular g-tensor were not lying along any preferential bond direction, indicating that, in high spin Co(II) ions in roughly octahedral geometry with approximately axial EPR signals, the presence of molecular pseudo axes in the metal site does not determine preferential directions for the molecular g-tensor. The EPR experiment and magnetic measurements, together with a theoretical analysis relating the coupling constants obtained from both techniques, allowed us to evaluate selectively the exchange coupling constant associated with hydrogen bonds that connect magnetically inequivalent Co(II) ions (|JAB(1/2)| = 0.055(2) cm(–1)) and the exchange coupling constant associated with a fumarate bridge connecting equivalent Co(II) ions (|JAA(1/2)| ? 0.25 (1) cm(–1)), in good agreement with the average J(3/2) value determined from magnetic measurements. PMID:24528370

  2. Rapid online equilibration method to determine the D/H ratios of non-exchangeable hydrogen in cellulose.

    PubMed

    Filot, Marc S; Leuenberger, Markus; Pazdur, Anna; Boettger, Tatjana

    2006-01-01

    An improved method for the determination of deuterium-to-hydrogen (D/H) ratios of non-exchangeable hydrogen in cellulose is presented. The method is based on the equilibration reaction of the hydroxyl hydrogen of cellulose and water vapour of known isotopic composition. The equilibrated cellulose is pyrolysed and the total D/H ratio determined by subsequent online isotope ratio mass spectrometry (IRMS). With a mass balance system the D/H ratio of non-exchangeable hydrogen is recalculated after an empirical calibration has been performed, yielding a mean exchangeability of 0.239 and an equilibrium fractionation factor of 1.082 between the hydroxyl hydrogen of cellulose and water hydrogen at 110 degrees C. Equilibration takes 10 min per sample. Results obtained by this online equilibration method agree very well with values obtained by the nitration technique (R2 = 0.941). The uncertainty of the equilibration method is +/-4 per thousand resulting from a single standard deviation of +/-2.8 per thousand for the equilibration determined by standard cellulose and 2.8 per thousand from the variable exchangeability of the hydroxyl hydrogen in cellulose due to crystalline areas. The latter uncertainty may be lowered by minimising the crystallinity of the cellulose. Advantages of this new technique are (i) the considerably reduced sample amount required (as low as 0.2 mg, ideally 0.5 mg compared with 20 mg for the conventional nitration technique); (ii) an approximately 100-fold reduced process time; and (iii) no need for the hazardous chemicals used in the nitration technique. PMID:17044122

  3. Isotope ratio measurements by secondary ion mass spectrometry (SIMS) and glow discharge mass spectrometry (GDMS)

    NASA Astrophysics Data System (ADS)

    Betti, Maria

    2005-04-01

    The basic principles of secondary ion mass spectrometry and glow discharge mass spectrometry have been shortly revisited. The applications of both techniques as exploited for the isotope ratio measurements in several matrices have been reviewed. Emphasis has been given to research fields in expansions such as solar system studies, medicine, biology, environment and nuclear forensic. The characteristics of the two techniques are discussed in terms of sensitivity and methodology of quantification. Considerations on the different detection possibilities in SIMS are also presented.

  4. Charge exchange of Si ions with clean and I-covered Al(100)

    NASA Astrophysics Data System (ADS)

    Chen, Xiaojian

    2005-03-01

    Ion-surface charge exchange is a central process in many surface analysis and processing methods. Charge exchange of alkali, halogen and noble gas ions with surfaces has been investigated in previous ion scattering studies, while the interaction between a semiconductor atom and a metal surface has not been measured despite its importance. Si^+ ions were incident on an atomically clean Al (100) surface in ultra-high vacuum. The absolute ionization probability of scattered Si and recoiled Al were measured with time-of-flight, and detailed spectra of the ion yield were collected with an electrostatic analyzer. All of the scattered Si was neutralized, as expected for resonant charge transfer (RCT) of Si, which has a large ionization potential. Multi-charged recoiled Al ions were emitted, however. Surprisingly, Si scattered from iodine adatoms is partially ionized and the ionization changes little with respect to the coverage, energy and exit angle. This is in direct contrast to Li scattering from I/Fe*, and cannot be explained by RCT. * J.A. Yarmoff, Y. Yang and Z. Sroubek, Phys. Rev. Lett. 91, 086104/1-4 (2003).

  5. U/Th dating by SHRIMP RG ion-microprobe mass spectrometry using single ion-exchange beads

    USGS Publications Warehouse

    Bischoff, J.L.; Wooden, J.; Murphy, F.; Williams, Ross W.

    2005-01-01

    We present a new analytical method for U-series isotopes using the SHRIMP RG (Sensitive High mass Resolution Ion MicroProbe) mass spectrometer that utilizes the preconcentration of the U-series isotopes from a sample onto a single ion-exchange bead. Ion-microprobe mass spectrometry is capable of producing Th ionization efficiencies in excess of 2%. Analytical precision is typically better than alpha spectroscopy, but not as good as thermal ionization mass spectroscopy (TIMS) and inductively coupled plasma multicollector mass spectrometry (ICP-MS). Like TIMS and ICP-MS the method allows analysis of small samples sizes, but also adds the advantage of rapidity of analysis. A major advantage of ion-microprobe analysis is that U and Th isotopes are analyzed in the same bead, simplifying the process of chemical separation. Analytical time on the instrument is ???60 min per sample, and a single instrument-loading can accommodate 15-20 samples to be analyzed in a 24-h day. An additional advantage is that the method allows multiple reanalyses of the same bead and that samples can be archived for reanalysis at a later time. Because the ion beam excavates a pit only a few ??m deep, the mount can later be repolished and reanalyzed numerous times. The method described of preconcentrating a low concentration sample onto a small conductive substrate to allow ion-microprobe mass spectrometry is potentially applicable to many other systems. Copyright ?? 2005 Elsevier Ltd.

  6. Comparison of chromatographic ion-exchange resins VI. Weak anion-exchange resins.

    PubMed

    Staby, Arne; Jensen, Randi Holm; Bensch, Matthias; Hubbuch, Jürgen; Dünweber, Dorte L; Krarup, Janus; Nielsen, Jacob; Lund, Mette; Kidal, Steffen; Hansen, Thomas Budde; Jensen, Inge Holm

    2007-09-14

    A comparative study on weak anion exchangers was performed to investigate the pH dependence, binding strength, particle size distribution, and static and dynamic capacity of the chromatographic resins. The resins tested included: DEAE Sepharose FF, Poros 50 D, Fractogel EMD DEAE (M), MacroPrep DEAE Support, DEAE Ceramic HyperD 20, and Toyopearl DEAE 650 M. Testing was performed with five different model proteins: Anti-FVII mAb (immunoglobulin G), aprotinin, bovine serum albumin (BSA), Lipolase (Novozymes), and myoglobin. Retention showed an expected increasing trend as a function of pH for proteins with low pI. A decrease in retention was observed for some resins at pH 9 likely due to initiation of deprotonation of the weak anion-exchange ligands. Expected particle size distribution was obtained for all resins compared to previous studies. Binding strength to weak anion-exchange resins as a function of ionic strength depends on the specific protein. Binding and elution at low salt concentration may be performed with Toyopearl DEAE 650 M, while binding and elution at high salt concentration may be performed with MacroPrep DEAE Support. Highest binding capacities were generally obtained with Poros 50 D followed by DEAE Ceramic HyperD 20. A general good agreement was obtained between this study and data obtained by the suppliers. Verification of binding strength trends with model proteins was achieved with human growth hormone (hGH) and a hGH variant on the same resins with different elution salts, sodium chloride, sodium hydrogenphosphate, sodium sulphate, and sodium acetate. Static capacity measurements obtained in the traditional experimental set-up were compared with high-throughput screening (HTS) technique experiments with reasonable agreement. Isotherm data obtained from HTS techniques and pulse experiments were successfully combined with mathematical modelling to simulate, develop and optimise the separation process of two model proteins, Lipolase and BSA. The data presented in this paper may be used for selection of resins for testing in process development. PMID:17658538

  7. A Multi-ion Model of the Heliosphere with Secondary Charge Exchange

    NASA Astrophysics Data System (ADS)

    Bedford, M. C.; Kryukov, I.; Pogorelov, N. V.

    2014-12-01

    Charge exchange between the solar wind (SW) and local interstellar medium (LISM) involves a complicated mixture of the unperturbed SW and LISM, primary pick-up ions (PUIs), and secondary PUIs and neutral atoms produced from multiple charge exchange processes. Furthermore, these processes are qualitatively different in each heliospheric region (supersonic SW, heliosheath, and LISM), potentially yielding over a dozen categories of charged and neutral particles with distinct properties as shown by kinetic simulations. We present a 3D multi-fluid MHD model with one primary and two secondary neutral fluids, an ion fluid for the mixture of SW and PUIs, and additional source terms for PUI pressure and density. Some charge exchanges produce hot ions which are grouped together as PUIs, while others produce ions with similar properties to the SW. This approach is supposed to bring the accuracy of the fluid model closer to that of kinetic models, in addition to reproducing phenomena observed by spacecraft, e.g., Voyager and IBEX.

  8. Ion exchange membrane cathodes for scalable microbial fuel cells.

    PubMed

    Zuo, Yi; Cheng, Shaoan; Logan, Bruce E

    2008-09-15

    One of the main challenges for using microbial fuel cells (MFCs) is developing materials and architectures that are economical and generate high power densities. The performance of two cathodes constructed from two low-cost anion (AEM) and cation (CEM) exchange membranes was compared to that achieved using an ultrafiltration (UF) cathode, when the membranes were made electrically conductive using graphite paint and a nonprecious metal catalyst (CoTMPP). The best performance in single-chamber MFCs using graphite fiber brush anodes was achieved using an AEM cathode with the conductive coating facing the solution, at a catalyst loading of 0.5 mg/cm2 CoTMPP. The maximum power densitywas 449 mW/ m2 (normalized to the projected cathode surface area) or 13.1 W/m3 (total reactor volume), with a Coulombic efficiency up to 70% in a 50 mM phosphate buffer solution (PBS) using acetate. Decreasing the CoTMPP loading by 40-80% reduced power by 28-56%, with only 16% of the power (72 mW/m2) generated using an AEM cathode lacking a catalyst. Using a current collector (a stainless steel mesh) pressed against the inside surface of the AEM cathode and 200 mM PBS, the maximum power produced was further increased to 728 mW/m2 (21.2 W/m3). The use of AEM cathodes and brush anodes provides comparable performance to similar systems that use materials costing nearly an order of magnitude more (carbon paper electrodes) and thus represent more useful materials for reducing the costs of MFCs for wastewater treatment applications. PMID:18853817

  9. Fabrication of spinel Li4-xTi5O12 via ion exchange for high-rate lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Cheng, Chongling; Liu, Hongjiang; Li, Jun; Xue, Xin; Cao, Hui; Wang, Dayang; Shi, Liyi

    2015-06-01

    The present work demonstrates that lithium ions can be stepwise substituted by protons from spinel Li4Ti5O12 crystalline particles though simple ion-exchange in aqueous HCl solution with the aid of heat treatment. This enables us to continuously tune the Li-to-Ti stoichiometric ratios from 0.80 to 0.59, 0.41, 0.21, 0.15, and 0.09, thus transforming Li4Ti5O12 to Li4-xTi5O12 nanocrystals. The resulting nanocrystals maintain the spinel crystal structure when x becomes smaller than 3. Among as-prepared the Li4-xTi5O12 crystalline particles, Li1Ti5O12 shows the highest capacity of 193 mAh g-1 at 1C and 148 mAh g-1 at 20C, lower current impedance (47 ?), significantly improved rate capability and fairly long cycle life. This excellent electrochemical performance makes spinel Li4-xTi5O12 particles as a promising anode candidate for lithium ion batteries superior.

  10. Electroreduction of oxygen on metal (Au, Cu)-ion exchanger nanocomposites in the diffusion mode

    NASA Astrophysics Data System (ADS)

    Gorshkov, V. S.; Polyanskii, L. N.; Kravchenko, T. A.

    2014-02-01

    The kinetics of the electroreduction of oxygen in the diffusion mode on single granules of nanocomposites consisting of dispersed particles of the metal (Au, Cu) of the nanometer size and macroporous sulfonic cation-exchanger matrix KU-23 is studied. No noticeable effect of the factors of size of the metal component and ion exchange over the matrix on the external diffusion current of oxygen reduction is observed. The drop in current observed in a number of cases is due to a transition to the mixed external and internal kinetics as a result of the macroporous structure of the matrix and the chemical activity of nanoparticles of the metal component.

  11. Two-electron exchange interaction between polar molecules and atomic ions — Asymptotic approach

    NASA Astrophysics Data System (ADS)

    Karbovanets, Oleksandr M.; Karbovanets, Myroslav I.; Khoma, Mykhaylo V.; Lazur, Volodymyr Yu.

    2015-05-01

    We have described the asymptotic approach for calculation of the two-electron exchange interaction between atomic ion and polar molecule responsible for direct double electron transfer processes. The closed analytic expression for matrix element of exchange interaction has been obtained in the framework of the semiclassical version of the asymptotic theory and point-dipole approximation for description of the polar molecule. Contribution to the Topical Issue "Elementary Processes with Atoms and Molecules in Isolated and Aggregated States", edited by Friedrich Aumayr, Bratislav Marinkovic, Štefan Matej?ik, John Tanis and Kurt H. Becker.

  12. Simultaneous determination of NH4+, NO2(-) and NO3(-) by ion-exclusion/anion-exchange chromatography on a strongly basic anion-exchange resin with basic eluent.

    PubMed

    Mori, Masanobu; Hironaga, Takahiro; Itabashi, Hideyuki; Nakatani, Nobutake; Kozaki, Daisuke; Tanaka, Kazuhiko

    2012-04-01

    Ion-exclusion/anion-exchange chromatography (IEC/AEC) on a combination of a strongly basic anion-exchange resin in the OH(-)-form with basic eluent has been developed. The separation mechanism is based on the ion-exclusion/penetration effect for cations and the anion-exchange effect for anions to anion-exchange resin phase. This system is useful for simultaneous separation and determination of ammonium ion (NH4+), nitrite ion (NO2(-)), and nitrate ion (NO3(-)) in water samples. The resolution of analyte ions can be manipulated by changing the concentration of base in eluent on a polystyrene-divinylbenzene based strongly basic anion-exchange resin column. In this study, several separation columns, which consisted of different particle sizes, different functional groups and different anion-exchange capacities, were compared. As the results, the separation column with the smaller anion-exchange capacity (TSKgel Super IC-Anion) showed well-resolved separation of cations and anions. In the optimization of the basic eluent, lithium hydroxide (LiOH) was used as the eluent and the optimal concentration was concluded to be 2 mmol/L, considering the resolution of analyte ions and the whole retention times. In the optimal conditions, the relative standard deviations of the peak areas and the retention times of NH4+, NO2(-), and NO3(-) ranged 1.28% - 3.57% and 0.54% - 1.55%, respectively. The limits of detection at signal-to-noise of 3 were 4.10 micromol/L for NH4+, 1.87 micromol/L for NO2(-) and 2.83 micromol/L for NO3(-). PMID:22799190

  13. LITERATURE REVIEWS TO SUPPORT ION EXCHANGE TECHNOLOGY SELECTION FOR MODULAR SALT PROCESSING

    SciTech Connect

    King, W

    2007-11-30

    This report summarizes the results of literature reviews conducted to support the selection of a cesium removal technology for application in a small column ion exchange (SCIX) unit supported within a high level waste tank. SCIX is being considered as a technology for the treatment of radioactive salt solutions in order to accelerate closure of waste tanks at the Savannah River Site (SRS) as part of the Modular Salt Processing (MSP) technology development program. Two ion exchange materials, spherical Resorcinol-Formaldehyde (RF) and engineered Crystalline Silicotitanate (CST), are being considered for use within the SCIX unit. Both ion exchange materials have been studied extensively and are known to have high affinities for cesium ions in caustic tank waste supernates. RF is an elutable organic resin and CST is a non-elutable inorganic material. Waste treatment processes developed for the two technologies will differ with regard to solutions processed, secondary waste streams generated, optimum column size, and waste throughput. Pertinent references, anticipated processing sequences for utilization in waste treatment, gaps in the available data, and technical comparisons will be provided for the two ion exchange materials to assist in technology selection for SCIX. The engineered, granular form of CST (UOP IE-911) was the baseline ion exchange material used for the initial development and design of the SRS SCIX process (McCabe, 2005). To date, in-tank SCIX has not been implemented for treatment of radioactive waste solutions at SRS. Since initial development and consideration of SCIX for SRS waste treatment an alternative technology has been developed as part of the River Protection Project Waste Treatment Plant (RPP-WTP) Research and Technology program (Thorson, 2006). Spherical RF resin is the baseline media for cesium removal in the RPP-WTP, which was designed for the treatment of radioactive waste supernates and is currently under construction in Hanford, WA. Application of RF for cesium removal in the Hanford WTP does not involve in-riser columns but does utilize the resin in large scale column configurations in a waste treatment facility. The basic conceptual design for SCIX involves the dissolution of saltcake in SRS Tanks 1-3 to give approximately 6 M sodium solutions and the treatment of these solutions for cesium removal using one or two columns supported within a high level waste tank. Prior to ion exchange treatment, the solutions will be filtered for removal of entrained solids. In addition to Tanks 1-3, solutions in two other tanks (37 and 41) will require treatment for cesium removal in the SCIX unit. The previous SCIX design (McCabe, 2005) utilized CST for cesium removal with downflow supernate processing and included a CST grinder following cesium loading. Grinding of CST was necessary to make the cesium-loaded material suitable for vitrification in the SRS Defense Waste Processing Facility (DWPF). Because RF resin is elutable (and reusable) and processing requires conversion between sodium and hydrogen forms using caustic and acidic solutions more liquid processing steps are involved. The WTP baseline process involves a series of caustic and acidic solutions (downflow processing) with water washes between pH transitions across neutral. In addition, due to resin swelling during conversion from hydrogen to sodium form an upflow caustic regeneration step is required. Presumably, one of these basic processes (or some variation) will be utilized for MSP for the appropriate ion exchange technology selected. CST processing involves two primary waste products: loaded CST and decontaminated salt solution (DSS). RF processing involves three primary waste products: spent RF resin, DSS, and acidic cesium eluate, although the resin is reusable and typically does not require replacement until completion of multiple treatment cycles. CST processing requires grinding of the ion exchange media, handling of solids with high cesium loading, and handling of liquid wash and conditioning solutions. RF processing requires h

  14. Disease-associated changes in the expression of ion channels, ion receptors, ion exchangers and Ca{sup 2+}-handling proteins in heart hypertrophy

    SciTech Connect

    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

    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.

  15. Ion-to-Neutral Ratios and Thermal Proton Transfer in Matrix-Assisted Laser Desorption/Ionization.

    PubMed

    Lu, I-Chung; Chu, Kuan Yu; Lin, Chih-Yuan; Wu, Shang-Yun; Dyakov, Yuri A; Chen, Jien-Lian; Gray-Weale, Angus; Lee, Yuan-Tseh; Ni, Chi-Kung

    2015-07-01

    The ion-to-neutral ratios of four commonly used solid matrices, ?-cyano-4-hydroxycinnamic acid (CHCA), 2,5-dihydroxybenzoic acid (2,5-DHB), sinapinic acid (SA), and ferulic acid (FA) in matrix-assisted laser desorption/ionization (MALDI) at 355 nm are reported. Ions are measured using a time-of-flight mass spectrometer combined with a time-sliced ion imaging detector. Neutrals are measured using a rotatable quadrupole mass spectrometer. The ion-to-neutral ratios of CHCA are three orders of magnitude larger than those of the other matrices at the same laser fluence. The ion-to-neutral ratios predicted using the thermal proton transfer model are similar to the experimental measurements, indicating that thermal proton transfer reactions play a major role in generating ions in ultraviolet-MALDI. Graphical Abstract ?. PMID:25851654

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

    SciTech Connect

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

    1995-11-01

    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 HNO{sub 3}). This paper presents results obtained for the material in batch ion exchange tests conducted at various solution pH values and in the presence of a number of competing cations. Results from a continuous flow column ion exchange experiment are also presented.

  17. Determination of plasma ion velocity distribution via charge-exchange recombination spectroscopy

    SciTech Connect

    Fonck, R.J.; Darrow, D.S.; Jaehnig, K.P.

    1983-12-01

    Spectroscopy of line radiation from plasma impurity ions excited by charge-exchange recombination reactions with energetic neutral beam atoms is rapidly becoming recognized as a powerful technique for measuring ion temperature, bulk plasma motion, impurity transport, and more exotic phenomena such as fast alpha particle distributions. In particular, this diagnostic offers the capability of obtaining space- and time-resolved ion temperature and toroidal plasma rotation profiles with relatively simple optical systems. Cascade-corrected excitation rate coefficients for use in both fully stripped impurity density studies and ion temperature measurements have been calculated to the principal ..delta..n = 1 transitions of He+, C/sup 5 +/, and O/sup 7 +/ with neutral beam energies of 5 to 100 keV/amu. A fiber optically coupled spectrometer system has been used on PDX to measure visible He/sup +/ radiation excited by charge exchange. Central ion temperatures up to 2.4 keV and toroidal rotation speeds up to 1.5 x 10/sup 7/ cm/s were observed in diverted discharges with P/sub INJ/ less than or equal to 3.0 MW.

  18. Transmittance properties and TEM observation of metal doped glass by field-assisted ion exchange

    NASA Astrophysics Data System (ADS)

    Matsusaka, Souta; Nomura, Taketsugu; Hidai, Hirofumi; Chiba, Akira; Morita, Noboru

    2014-08-01

    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.

  19. Ultra-low vanadium ion diffusion amphoteric ion-exchange membranes for all-vanadium redox flow batteries

    NASA Astrophysics Data System (ADS)

    Liao, J. B.; Lu, M. Z.; Chu, Y. Q.; Wang, J. L.

    2015-05-01

    An amphoteric ion-exchange membrane (AIEM) from fluoro-methyl sulfonated poly(arylene ether ketone) bearing content-controlled benzimidazole moiety, was firstly fabricated for vanadium redox flow battery (VRB). The AIEM and its covalently cross-linked membrane (AIEM-c) behave the highly suppressed vanadium-ion crossover and their tested VO2+ permeability are about 638 and 1117 times lower than that of Nafion117, respectively. This is further typically verified by the lower VO2+ concentration inside AIEM that is less than half of that inside Nafion117 detected by energy dispersive X-ray spectrometry, in addition of the nearly 3 times longer battery self-discharge time. The ultra-low vanadium ion diffusion could be ascribed to the narrower ion transporting channel originated from the acid-base interactions and the rebelling effect between the positively-charged benzimidazole structure and VO2+ ions. It is found that, VRB assembled with AIEM exhibits the equal or higher Coulombic efficiency (99.0% vs. 96.4%), voltage efficiency (90.7% vs. 90.7%) and energy efficiency (89.8% vs. 87.4%) than that with Nafion117 and keeps continuous 220 charge-discharge cycles for over 25 days, confirming that the AIEM of this type is a potentially suitable separator for VRB application.

  20. Modulation of terrestrial ion escape flux composition /by low-altitude acceleration and charge exchange chemistry/

    NASA Technical Reports Server (NTRS)

    Moore, T. E.

    1980-01-01

    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.

  1. Hydrogen production in the K-Basin ion exchange columns, modules and cartridge filters

    SciTech Connect

    Not Available

    1994-12-21

    K-Basin uses ion exchange modules and ion exchange (IX) columns for removing radionuclides from the basin water. When the columns and modules are loaded, they are removed from service, drained and stored. After a few IX columns accumulate in storage, they are moved to a burial box. One of the burial box contains 33 columns and the other, six. The radionuclides act on the liquid left within and adhering to the beads to produce hydrogen. This report describes the generation rate, accumulation rate and significance of that accumulation. This summary also highlights those major areas of concern to the external (to Westinghouse Hanford Company [WHC]) reviewers. Appendix H presents the comments made by the external reviewers and, on a separate sheet, the responses to those comments. The concerns regarding the details of the analytical approach, are addressed in Appendix H and in the appropriate section.

  2. An evaluation of organic substance fraction removal during ion exchange with Miex-DOC resin.

    PubMed

    Wolska, Ma?gorzata

    2015-07-01

    In this study, the usefulness of Miex-DOC resin in eliminating organic substances and their fractions from water sources for drinking water was evaluated. The objects of study were samples from three surface water sources and one infiltration water source taken at water treatment plants before treatment in technical conditions. In particular, the effectiveness of removing biodegradable and non-biodegradable fractions as a function of resin dosages and water-resin contact times was evaluated. The ion exchange process with the Miex-DOC resin achieved a high effectiveness in removing aromatic non-biodegradable organic substances, and therefore a reduction in UV254 absorbance. The biodegradable fraction is much less susceptible to removal yet its removal effectiveness allows for a significant reduction in hazards connected with secondary microorganism development. The results of this study indicate the possibility of using ion exchange with the Miex-DOC resin for effective removal of disinfection by-product precursors. PMID:25976333

  3. The characteristic assessment of spent ion exchange resin from PUSPATI TRIGA REACTOR (RTP) for immobilization process

    SciTech Connect

    Wahida, Nurul [School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia and Malaysian Nuclear Agency, Bangi 43000 Kajang, Selangor (Malaysia); Yasir, Muhamad Samudi; Majid, Amran Ab; Irwan, M. N. [School of Applied Physics, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia); Wahab, Mohd Abd; Marzukee, Nik; Paulus, Wilfred; Phillip, Esther; Thanaletchumy [Malaysian Nuclear Agency, Bangi 43000 Kajang, Selangor (Malaysia)

    2014-09-03

    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 {sup 134}Cs, {sup 137}Cs, {sup 152}Eu, {sup 54}Mn, {sup 58}Co, {sup 60}Co and {sup 65}Zn. The leachability test shows a small concentrations (<1 Bq/l) of {sup 152}Eu and {sup 134}Cs were leached out from the spent resin while {sup 60}Co 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.

  4. The load and release characteristics on a strong cationic ion-exchange fiber: kinetics, thermodynamics, and influences

    PubMed Central

    Yuan, Jing; Gao, Yanan; Wang, Xinyu; Liu, Hongzhuo; Che, Xin; Xu, Lu; Yang, Yang; Wang, Qifang; Wang, Yan; Li, Sanming

    2014-01-01

    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

  5. Eucalyptus hydrolysate detoxification with activated charcoal adsorption or ion-exchange resins for xylitol production

    Microsoft Academic Search

    Larissa Canilha; João Batista de Almeida e Silva; Ana Irene Nápoles Solenzal

    2004-01-01

    Eucalyptus hemicellulosic hydrolysate used for xylitol production by Candida guilliermondii FTI20037 was previously treated either with ion-exchange resins or with activated charcoal adsorption combined with pH adjustment, in order that acetic acid, furfural and hydroxymethylfurfural could be removed. The best results for xylitol yield factor (0.76g\\/g) and volumetric productivity (0.68g\\/(lh) were attained when a three-fold concentrated hydrolysate was treated with

  6. Preparation and characterization of PVdF nanofiber ion exchange membrane for the PEMFC application

    Microsoft Academic Search

    Won Gi Jang; Jian Hou; Hong sik Byun

    2011-01-01

    This paper reports the preparation and characterization of polyvinylidene fluoride (PVdF) nanofiber ion exchange membrane for the application in polymer electrolyte membrane fuel cells (PEMFC). The composite membrane of PS\\/PVdF was prepared by using the electrospinning method with PVdF solution in a mixed solvent of DMAc and acetone by pore-filling with a mixture of styrene and PS using DVB as

  7. Ion exchange recovery of Ni(II) from simulated electroplating waste solutions containing anionic ligands

    Microsoft Academic Search

    Ruey-Shin Juang; Hsiang-Chien Kao; Fong-Yi Liu

    2006-01-01

    Ion exchange is widely used for the recovery and removal of metals from process and waste streams in chemical process industries. The Na-form of strong-acid Purolite NRW-100 resin was used to recover Ni(II) from a simulated electroplating waste solution containing NiSO4, NH4Cl, NaH2PO4, and citrate. A set of mass balance equations that take into account possible aqueous complexation reactions was

  8. Lithium isotope separation on an ion exchange resin having azacrown ether as an anchor group

    Microsoft Academic Search

    D. W. Kim; Ch. P. Hong; Ch. S. Kim; Y. K. Jeong; Y. Sh. Jeon; J. K. Lee

    1997-01-01

    A study on the separation of lithium isotopes was carried out with an ion exchange resin having 1,7,13-trioxa-4,10,16-triazacyclooctadecane (N3O3) as an anchor group. The lighter isotope,6Li concentrated in the resin phase, while the heavier isotope,7Li is enriched in the fluid phase. Upon column chromatography [0.6 cm (I. D.)×20 cm (height)] using 1.0M ammonium chloride solution as an eluent, single separation

  9. About the single-stage separation coefficient of lithium isotopes by the ion-exchange method

    Microsoft Academic Search

    G. M. Panchenkov; E. M. Kuznetsova; O. N. Kaznadzei

    1961-01-01

    authors, oscillates from 1.016 to 1.021, and the solution is always enriched in the light isotope. In our work, we have considered the problem of determining the coefficient of single-stage separation of lithium isotopes for the ion-exchange reaction on domestic eationite, and also of clarifying the dependence of this coefficient upon the nature of the salts and of the cationites,

  10. Exploring the favorable ion-exchange ability of phthalylated cellulose biopolymer using thermodynamic data

    Microsoft Academic Search

    Júlio C. P. de Melo; Edson C. da Silva Filho; Sirlane A. A. Santana; Claudio Airoldi

    2010-01-01

    A phthalylated ion-exchange biopolymer was obtained by adding cellulose to molten phthalic anhydride in a quasi solvent-free procedure. Through this route 2.99±0.07mmolg?1 of pendant groups containing ester and carboxylic acid moieties were incorporated into the polymeric structure that was characterized by elemental analysis, solid-state carbon nuclear magnetic resonance (CP\\/MAS), infrared spectroscopy, X-ray diffraction, and thermogravimetry. The chemically modified polysaccharide is

  11. Purification of C-Phycocyanin from Spirulina platensis by Single-Step Ion-Exchange Chromatography

    Microsoft Academic Search

    Xiaoxia Liao; Bochao Zhang; Xiaoqin Wang; Huidan Yan; Xuewu Zhang

    2011-01-01

    C-Phycocyanin is a natural blue pigment with many commercial applications in foods, cosmetics, and medicines. In this paper\\u000a we describe the extraction and purification of C-phycocyanin from the cyanobacterium Spirulina platensis. The procedure is based on adsorption of impurities with chitosan and activated charcoal then one-step ion-exchange chromatography.\\u000a The dry algal powder was soaked in potassium phosphate buffer for 2 h

  12. Exchange bias studies of NiFe\\/FeMn\\/NiFe trilayer by ion beam etching

    Microsoft Academic Search

    V. K. Sankaranarayanan; D. Y. Kim; S. M. Yoon; C. O. Kim; C. G. Kim

    2005-01-01

    Effect of low energy ion beam etching on exchange bias in NiFe\\/FeMn\\/NiFe trilayer is investigated in multilayers prepared by rf magnetron sputtering. Stepwise etching and magnetization measurement of FeMn layer in an NiFe\\/FeMn bilayer show increase of bias as etching proceeds and FeMn thickness decreases. The bias show a maximum around 7 nm FeMn thickness and then fall sharply below

  13. Ion exchange membrane-platinum composites as electrically controllable artificial muscles

    NASA Astrophysics Data System (ADS)

    Mojarrad, Mehran; Shahinpoor, Mohsen

    1996-04-01

    Ion exchange membranes (JEM) chemically treated with platinum salt so1uions gives rise to IEM-platinum composites that undergo large deformations in an electric field of a few volts (2-4 volts/mm). They also show remarkable vibrational characteristics of about 80 lIz bandwidth. A simple theoretical treatment as well as some experimental evidence on the dependence of deformation amplitude on the imposed voltages and frequencies are presented.

  14. High Pt utilization PEMFC electrode obtained by alternative ion-exchange/electrodeposition.

    PubMed

    Chen, Siguo; Wei, Zidong; Li, Hua; Li, Li

    2010-12-14

    High Pt utilization PEMFC electrodes were prepared by an alternative ion-exchange/electrodeposition (AIEE) technique. The results demonstrated that the MEA employing an AIEE electrode with a Pt loading of 0.014 mg Pt cm(-2) exhibits performance approximately 2.2 times larger than that employing a conventional Nafion-bonded Pt/C electrode with a same Pt loading. PMID:20963211

  15. THE EXTRACTION OF SILVER FROM CYANIDE SOLUTIONS WITH ION EXCHANGE RESINS

    Microsoft Academic Search

    P. A. Riveros; W. Charles Cooper

    1985-01-01

    The ability of various ion exchange resins to extract silver from synthetic cyanide solutions was evaluated. It was found that weak base resins such as DUOLITE A-7, DOWEX WGR-2, DOWEX MWA-1, DOWEX XFS-4195, and AMBERLITE IRA-35 extract silver significantly only when the pH is lower than 8. At higher pH, the same resins exhibited little or no silver extraction. A

  16. Cesium removal from dilute streams with Epicor CS1 ion exchange resin

    Microsoft Academic Search

    Kilpatrick

    1985-01-01

    A laboratory scale ion exchange facility was used to evaluate Epicor CS-1's capability to remove cesium from a dilute NaNOâ stream (600 ppM and 300 ppM Na). Plots of % concentration change of cesium versus column volumes passed were made for the load and for the elution cycles. (See Appendix A and B). NaNOâ and HNOâ were used as elutriants.

  17. Recovery of vanillin from Kraft lignin oxidation by ion-exchange with neutralization

    Microsoft Academic Search

    M. Zabkova; E. A. Borges da Silva; A. E. Rodrigues

    2007-01-01

    This paper deals with the recovery of vanillin from Kraft lignin oxidation using an ion-exchange process with neutralization. In order to produce vanillin, oxidation of lignin takes place in the presence of alkaline medium (pH 12–13); under such condition almost all vanillin is present as vanillate. The goal of this work is the vanillin recovery that is achieved by passing

  18. Recovery of uranium from phosphoric acid solutions using chelating ion-exchange resins

    Microsoft Academic Search

    N. Kabay; M. Demircioglu; S. Yayh; E. Guenay; M. Yueksel; M. Saglam; M. Streat

    1998-01-01

    In fertilizer manufacture, calcium phosphate in phosphate rock is rendered soluble by sulfuric acid attack. The phosphoric acid obtained in this way usually contains 26%--28% PâOâ. Several novel processes have been developed for the recovery of uranium from wet-process phosphoric acid. Experimental measurements have been made on the batch extraction of uranium from phosphoric acid solutions using various chelating ion-exchange

  19. Study on elution ability of salicylic acid on ion exchange resins in supercritical carbon dioxide

    Microsoft Academic Search

    Ping Yuan; Jianguo Cai; Junjie Gong; Xiu Deng

    2009-01-01

    The elution ability of salicylic acid on ion exchange resins in supercritical carbon dioxide has been studied. Some factors\\u000a influencing elution recovery, including entrainer, temperature, pressure and the flow rate of supercritical fluid CO2 are discussed in this work. The addition of a small amount of entrainer, such as ethanol, triethanolamine and their mixture\\u000a to supercritical CO2 can cause dramatic

  20. Calcium Hydroxide Isotope Effect in Calcium Isotope Enrichment by Ion Exchange

    Microsoft Academic Search

    B. E. Jepson; G. C. Shockey

    1984-01-01

    The enrichment of calcium isotopes has been observed in ion-exchange chroma-tography with an aqueous phase of calcium hydroxide and a solid phase of sulfonic acid resin. The band front was exceedingly sharp as a result of the acid-base reaction occurring at the front of the band. Single-stage separation coefficients were found to be (Ca\\/Ca) = 11 × 10 and (Ca\\/Ca)

  1. Hydraulic Performance and Gas Behavior of a Tall Crystalline Silicotitanate Ion-Exchange Column

    Microsoft Academic Search

    T. D. Welch; K. K. Anderson; D. A. Bostick; T. A. Dillow; R. D. Hunt; R. Lenarduzzi; A. J. Mattus; P. A. Taylor; W. R. Wilmarth

    2000-01-01

    Crystalline silicotitanate (CST) sorbent is one of several technologies being evaluated by the Savannah River Site (SRS) for removing cesium from high-level tank-waste supernatant. As currently envisioned, three large 5-ft-diam, 20-ft-high ion-exchange columns will be operated in series at a superficial velocity of 4.1 cm\\/min. The CST will be subjected to a high radiation field from the sorbed cesium. The

  2. Multiple Ion Exchange Column Tests for Technetium Removal from Hanford Tank Waste Supernate

    Microsoft Academic Search

    Hassan

    2004-01-01

    Five cycles of loading, elution, and regeneration were performed to remove technetium from a Hanford waste sample retrieved from Tank 241-AW-101 using SuperLig 639 resin. The waste sample was diluted to 4.95 M Na plus and then was processed to remove 137Cs through dual ion exchange columns each containing 15 mL of SuperLig 644. To remove 99Tc, the cesium decontaminated

  3. Repeated use of ion-exchange resin membranes in calcareous soils

    USGS Publications Warehouse

    Sherrod, S.K.; Belnap, Jayne; Miller, M.E.

    2003-01-01

    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 single-use.

  4. Ion-exchange membranes: preparative methods for electrodialysis and fuel cell applications

    Microsoft Academic Search

    M. Y. Kariduraganavar; R. K. Nagarale; A. A. Kittur; S. S. Kulkarni

    2006-01-01

    Ion-exchange membranes have been used in various industrial processes, e.g., in the electrodialytic concentration of seawater to produce edible salt, as a separator for electrolysis, in the desalination of saline water by electrodialysis, in the separation of ionic materials from non-ionic materials by electrodialysis, in the recovery of acid and alkali from waste acid and alkali solution by diffusion dialysis,

  5. Magnetization reversal and enhanced tunnel magnetoresistance ratio in perpendicular magnetic tunnel junctions based on exchange spring electrodes

    NASA Astrophysics Data System (ADS)

    Wang, Yi; Yin, Xiaolu; Le Roy, D.; Jiang, Jun; Wei, H. X.; Liou, S. H.; Han, X. F.

    2013-04-01

    The [Co/Pt]n multilayer based perpendicular magnetic tunnel junction stacks with wedged Co60Fe20B20 insertions up to 2 nm, and corresponding perpendicular magnetic tunnel junctions were magnetically and electrically investigated. The focus is on the influence of CoFeB insertions in the free and reference electrodes on the overall junction magnetization reversal and magnetoresistance response. The exchange spring behavior was revealed as the Co60Fe20B20 spins canting towards the in-plane direction in the [Co/Pt]n/Co60Fe20B20 hard/soft perpendicular magnetic electrodes. The broad range thickness of wedged Co60Fe20B20 insertion enables to reveal the critical transition, in particular, from rigid coupling to exchange spring coupling. With the help of 375°C annealing under 10 kOe magnetic field, the recovery from distinct multi-domain structure to nearly single domain structure was distinctly observed in the unpatterned perpendicular magnetic tunnel junction (p-MTJ) films with CoFeB thickness tCFB?1.5 nm. Meanwhile, for the corresponding patterned perpendicular magnetic tunnel junctions with AlOx barrier, the tunnel magnetoresistance (TMR) ratio exhibited an intense enhancement over 100%. The TMR results and spin configurations were illustrated using an exchange spring model in both magnetic electrodes. The presented study shows the benefit of using exchange spring magnetic electrodes in perpendicular magnetic tunnel junction on their performance.

  6. Solar Wind Charge Exchange Studies of Highly Charged Ions on Atomic Hydrogen

    SciTech Connect

    Draganic, Ilija N [ORNL; Seely, D. G. [Albion College; McCammon, D [University of Wisconsin, Madison; Havener, Charles C [ORNL

    2011-01-01

    Accurate studies of low energy charge exchange (CX) are critical to understanding underlying soft X ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H like, and He like ions of C, N, O and Ne, which are the dominant charge states for these heavier elements in the solar wind. Absolute total cross sections for single electron capture by H like ions of C, N, O and fully stripped O ions from atomic hydrogen have been measured in an expanded range of relative collision energies (5 eV u 20 keV u) and compared to previous H oven measurements. The present measurements are performed using a merged beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source installed on a high voltage platform at the Oak Ridge National Laboratory. For the collision energy range of 0.3 keV u 3.3 keV u, which corresponds to typical ion velocities in the solar wind, the new measurements are in good agreement with previous H oven measurements. The experimental results are discussed in detail and compared with theoretical calculations where available.

  7. Latex-coated polymeric monolithic ion-exchange stationary phases. 1. Anion-exchange capillary electrochromatography and in-line sample preconcentration in capillary electrophoresis.

    PubMed

    Hutchinson, Joseph P; Zakaria, Philip; Bowie, Andrew R; Macka, Miroslav; Avdalovic, Nebojsa; Haddad, Paul R

    2005-01-15

    A sulfonated methacrylate monolithic polymer has been synthesized inside fused-silica capillaries of diameters 50-533-microm i.d. and coated with 65-nm-diameter fully functionalized quaternary ammonium latex particles (AS18, Dionex Corp.) to form an anion-exchange stationary phase. This stationary phase was used for ion-exchange capillary electrochromatography of inorganic anions in a 75-microm-i.d. capillary with Tris/perchlorate electrolyte and direct UV detection at 195 nm. Seven inorganic anions (bromide, nitrate, iodide, iodate, bromate, thiocyanate, chromate) could be separated over a period of 90 s, and the elution order indicated that both ion exchange and electrophoresis contributed to the separation mechanism. Separation efficiencies of up to 1.66 x 10(5) plates m(-1) were achieved, and the monoliths were stable under pressures of up to 62 MPa. Another latex-coated monolith in a 250-microm-i.d. capillary was used for in-line preconcentration by coupling it to a separation capillary in which the EOF had been reversed using a coating of either a cationic polymer or cationic latex particles. Several capillary volumes of sample were loaded onto the preconcentration monolith, and the analytes (inorganic anions) were then eluted from the monolith with a transient isotachophoretic gradient before being separated by electrophoresis in the separation capillary. Linear calibration curves were obtained for aqueous mixtures of bromide, nitrite, nitrate, and iodide. Recoveries of all analytes except iodide were reduced significantly when the sample matrix contained high levels of chloride. The preconcentration method was applied to the determination of iodide in open ocean water and provided a limit of detection of 75 pM (9.5 ng/L) calculated at a signal-to-noise ratio of 3. The relative standard deviation for migration time and peak area for iodide were 1.1 and 2.7%, respectively (n = 6). Iodide was eluted as an efficient peak, yielding a separation efficiency of 5.13 x 10(7) plates m(-1). This focusing was reproducible for repeated analyses of seawater. PMID:15649035

  8. Dissociative recombination of water cluster ions with free electrons: Cross sections and branching ratios

    SciTech Connect

    Oejekull, J.; Andersson, P. U.; Pettersson, J. B. C.; Markovic, N.; Thomas, R. D.; Al Khalili, A.; Ehlerding, A.; Oesterdahl, F.; Ugglas, M. af; Larsson, M.; Danared, H.; Kaellberg, A. [Department of Chemistry, Atmospheric Science, Goeteborg University, SE-412 96 Goeteborg (Sweden); Department of Chemical and Biological Engineering, Physical Chemistry, Chalmers University of Technology, SE-412 96 Goeteborg (Sweden); Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm (Sweden); Manne Siegbahn Laboratory, Frescativaegen 28, SE-104 05 Stockholm (Sweden)

    2008-01-28

    Dissociative recombination (DR) of water cluster ions H{sup +}(H{sub 2}O){sub n} (n=4-6) with free electrons has been studied at the heavy-ion storage ring CRYRING (Manne Siegbahn Laboratory, Stockholm University). For the first time, branching ratios have been determined for the dominating product channels and absolute DR cross sections have been measured in the energy range from 0.001 to 0.7 eV. Dissociative recombination is concluded to result in extensive fragmentation for all three cluster ions, and a maximum number of heavy oxygen-containing fragments is produced with a probability close to unity. The branching ratio results agree with earlier DR studies of smaller water cluster ions where the channel nH{sub 2}O+H has been observed to dominate and where energy transfer to internal degrees of freedom has been concluded to be highly efficient. The absolute DR cross sections for H{sup +}(H{sub 2}O){sub n} (n=4-6) decrease monotonically with increasing energy with an energy dependence close to E{sup -1} in the lower part of the energy range and a faster falloff at higher energies, in agreement with the behavior of other studied heavy ions. The cross section data have been used to calculate DR rate coefficients in the temperature range of 10-2000 K. The results from storage ring experiments with water cluster ions are concluded to partly confirm the earlier results from afterglow experiments. The DR rate coefficients for H{sup +}(H{sub 2}O){sub n} (n=1-6) are in general somewhat lower than reported from afterglow experiments. The rate coefficient tends to increase with increasing cluster size, but not in the monotonic way that has been reported from afterglow experiments. The needs for further experimental studies and for theoretical models that can be used to predict the DR rate of polyatomic ions are discussed.

  9. Perchlorate Degradation Using Partially Oxidized Titanium Ions and Ion Exchange Membrane Hybrid System 

    E-print Network

    Park, Sung Hyuk

    2011-08-08

    Perchlorate has entered human and environmental food chains and has received a great deal of attention because of its toxicity to humans. In this study, chemical degradation of perchlorate was investigated using partially oxidized titanium ions (Ti2...

  10. Perchlorate Degradation Using Partially Oxidized Titanium Ions and Ion Exchange Membrane Hybrid System

    E-print Network

    Park, Sung Hyuk

    2011-08-08

    Perchlorate has entered human and environmental food chains and has received a great deal of attention because of its toxicity to humans. In this study, chemical degradation of perchlorate was investigated using partially oxidized titanium ions (Ti2...

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

    PubMed

    Lee, I Hsien; Kuan, Yu-Chung; Chern, Jia-Ming

    2006-12-01

    Wastewaters containing heavy metals are usually treated by chemical precipitation method in Taiwan. This method can remove heavy metals form wastewaters efficiently, but the resultant heavy metal sludge is classified as hazardous solid waste and becomes another environmental problem. If we can remove heavy metals from sludge, it becomes non-hazardous waste and the treatment cost can be greatly reduced. This study aims at using ion-exchange resin to remove heavy metals such as copper, zinc, cadmium, and chromium from sludge generated by a PCB manufacturing plant. Factorial experimental design methodology was used to study the heavy metal removal efficiency. The total metal concentrations in the sludge, resin, and solution phases were measured respectively after 30 min reaction with varying leaching agents (citric acid and nitric acid); ion-exchange resins (Amberlite IRC-718 and IR-120), and temperatures (50 and 70 degrees C). The experimental results and statistical analysis show that a stronger leaching acid and a higher temperature both favor lower heavy metal residues in the sludge. Two-factors and even three-factor interaction effects on the heavy metal sorption in the resin phase are not negligible. The ion-exchange resin plays an important role in the sludge extraction or metal recovery. Empirical regression models were also obtained and used to predict the heavy metal profiles with satisfactory results. PMID:16843592

  12. Discerning the role of topography and ion exchange in cell response of bioactive tissue engineering scaffolds.

    PubMed

    Engel, Elisabeth; Del Valle, Sergio; Aparicio, Conrado; Altankov, George; Asin, Luis; Planell, Josep A; Ginebra, Maria-Pau

    2008-08-01

    Surface topography is known to have an influence on osteoblast activity. However, in the case of bioactive materials, topographical changes can affect also ion exchange properties. This makes the problem more complex, since it is often difficult to separate the strictly topographical effects from the effects of ionic fluctuations in the medium. The scope of this paper is to analyze the simultaneous effect of topography and topography-mediated ion exchange on the initial cellular behavior of osteoblastic-like cells cultured on bioactive tissue engineering substrates. Two apatitic substrates with identical chemical composition but different micro/nanostructural features were obtained by low-temperature setting of a calcium phosphate cement. MG63 osteoblastic-like cells were cultured either in direct contact with the substrates or with their extracts. A strong and permanent decrease of calcium concentration in the culture medium, dependent on substrate topography, was detected. A major effect of the substrate microstructure on cell proliferation was observed, explained in part by the topography-mediated ion exchange, but not specifically by the ionic Ca(2+) fluctuations. Cell differentiation was strongly enhanced when cells were cultured on the finer substrate. This effect was not explained by the chemical modification of the medium, but rather suggested a strictly topographical effect. PMID:18680388

  13. IMPACT OF THE SMALL COLUMN ION EXCHANGE PROCESS ON THE DEFENSE WASTE PROCESSING FACILITY - 12112

    SciTech Connect

    Koopman, D.; Lambert, D.; Fox, K.; Stone, M.

    2011-11-07

    The Savannah River Site (SRS) is investigating the deployment of a parallel technology to the Salt Waste Processing Facility (SWPF, presently under construction) to accelerate high activity salt waste processing. The proposed technology combines large waste tank strikes of monosodium titanate (MST) to sorb strontium and actinides with two ion exchange columns packed with crystalline silicotitanate (CST) resin to sorb cesium. The new process was designated Small Column Ion Exchange (SCIX), since the ion exchange columns were sized to fit within a waste storage tank riser. Loaded resins are to be combined with high activity sludge waste and fed to the Defense Waste Processing Facility (DWPF) for incorporation into the current glass waste form. Decontaminated salt solution produced by SCIX will be fed to the SRS Saltstone Facility for on-site immobilization as a grout waste form. Determining the potential impact of SCIX resins on DWPF processing was the basis for this study. Accelerated salt waste treatment is projected to produce a significant savings in the overall life cycle cost of waste treatment at SRS.

  14. TRANSIENT HEAT TRANSFER ANALYSIS FOR ION-EXCHANGE WASTE REMOVAL PROCESS

    SciTech Connect

    Lee, S.

    2010-07-12

    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.

  15. Evaluation of ion exchange resins and various enzymes in thiamine analysis.

    PubMed

    Ellefson, W C; Richter, E; Adams, M; Baillies, N T

    1981-11-01

    Four ion exchange resins and 9 enzyme preparations are evaluated for use in the official AOAC thiamine method because Decalso and Clarase or Mylase P either are no longer available or are available in a form that is not suitable for use in the assay. The enzymes are prepared in the same manner described for Clarase or Mylase P in the AOAC method and are compared with Clarase T300 for their effectiveness in releasing thiamine from thiamine phosphate, and their ability to produce similar results on samples. Rhozyme S is 90-100% as effective as Clarase T300 in both of these respects. The other enzymes tested were not satisfactory. Further study is necessary because Rhozyme S also is no longer manufactured. The ion exchange resins are prepared for use in the manner described for Decalso in the AOAC method. Recoveries of thiamine range from 95 to 100%, using Bio-Rex 70 (hydrogen form) ion exchange resin. The other resins tested were not satisfactory. PMID:7309654

  16. Ion exchange at the electrode/electrolyte interface studied by probe beam deflection techniques.

    PubMed

    Barbero, César A

    2005-05-01

    Probe beam deflection (PBD) techniques are a set of in situ electrochemical methods based on the measurement of refractive index gradients in front of the electrode/electrolyte interface. Here, the details of the techniques are described. First, the theory of potential step chronodeflectometry and pulse voltadeflectometry is discussed. Later, different numerical procedures used for data processing and/or simulation of cyclic voltadeflectometry experiments are described. Then, an overview is performed of the techniques use to study electrochemical systems. The systems described are limited to surface species in binary electrolytes, where a clear interpretation of the data is possible. Among the systems studied are: surface reactions on solid electrodes, electrochromic oxides, conducting polymers, redox polymers, double layer charging in nanostructured carbons and ion exchange in layer-by-layer self assembled multilayers. It is shown that PBD techniques have been able to ascertain the effect of different factors on ion exchange: anion size, pH, solvent, film composition, covalent modification, etc. The capability of the techniques to perform fast measurements was also used with success to find out kinetic effects on the ion exchange. PMID:19787889

  17. Effects of ion exchange on stream solute fluxes in a basin receiving highway deicing salts

    USGS Publications Warehouse

    Shanley, J.B.

    1994-01-01

    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.

  18. Kinetic Electron and Ion Instability of the Lunar Wake Simulated at Physical Mass Ratio

    E-print Network

    Haakonsen, Christian Bernt; Zhou, Chuteng

    2015-01-01

    The solar wind wake behind the moon is studied with 1D electrostatic particle-in-cell (PIC) simulations using a physical ion to electron mass ratio (unlike prior investigations); the simulations also apply more generally to supersonic flow of dense magnetized plasma past non-magnetic objects. A hybrid electrostatic Boltzmann electron treatment is first used to investigate the ion stability in the absence of kinetic electron effects, showing that the ions are two-stream unstable for downstream wake distances (in lunar radii) greater than about three times the solar wind Mach number. Simulations with PIC electrons are then used to show that kinetic electron effects can lead to disruption of the ion streams at least three times closer to the moon than in the hybrid simulations. This disruption occurs as the result of a novel wake phenomenon: the non-linear growth of electron holes spawned from a narrow dimple in the electron velocity distribution. Most of the holes arising from the dimple are small and quickly l...

  19. Rapid preparation of biosorbents with high ion exchange capacity from rice straw and bagasse for removal of heavy metals.

    PubMed

    Rungrodnimitchai, Supitcha

    2014-01-01

    This work describes the preparation of the cellulose phosphate with high ion exchange capacity from rice straw and bagasse for removal of heavy metals. In this study, rice straw and bagasse were modified by the reaction with phosphoric acid in the presence of urea. The introduced phosphoric group is an ion exchangeable site for heavy metal ions. The reaction by microwave heating yielded modified rice straw and modified bagasse with greater ion exchange capacities (?3.62?meq/g) and shorter reaction time (1.5-5.0?min) than the phosphorylation by oil bath heating. Adsorption experiments towards Pb²?, Cd²?, and Cr³? ions of the modified rice straw and the modified bagasse were performed at room temperature (heavy metal concentration 40?ppm, adsorbent 2.0?g/L). The kinetics of adsorption agreed with the pseudo-second-order model. It was shown that the modified rice straw and the modified bagasse could adsorb heavy metal ions faster than the commercial ion exchange resin (Dowax). As a result of Pb²? sorption test, the modified rice straw (RH-NaOH 450W) removed Pb²? much faster in the initial step and reached 92% removal after 20?min, while Dowax (commercial ion exchange resin) took 90?min for the same removal efficiency. PMID:24578651

  20. Preparation and characterization of 5-sulphosalicylic acid doped tetraethoxysilane composite ion-exchange material by sol-gel method.

    PubMed

    Rehman, Suhail-ul; Islam, Nasarul; Ahad, Sozia; Fatima, Syed Zeeshan; Pandith, Altaf Hussain

    2013-09-15

    In this manuscript, we report the preparation and characterization of sulphosalicylic doped tetraethoxysilane (SATEOS), composite material by sol-gel method as a new ion exchanger for the removal of Ni(II) from aqueous solution. The fine granular material was prepared by acid catalyzed condensation polymerization through sol-gel mechanism in the presence of cationic surfactant. The material has an ion exchange capacity of 0.64 mequiv./g(dry) for sodium ions, 0.60 mequiv./g(dry) for potassium ions, 1.84 mequiv./g(dry) for magnesium ions, 1.08 mequiv./g(dry) for calcium ions and 1.36 mequiv./g(dry) for strontium ions. Its X-ray diffraction studies suggest that it is crystalline in nature. The material has been characterized by SEM, IR, TGA and DTG so as to identify the various functional groups and ion exchange sites present in this material. Quantum chemical computations at DFT/B3LYP/6-311G (d,p) level on model systems were performed to substantiate the structural conclusions based ion instrumental techniques. Investigations into the elution behaviour, ion exchange reversibility and distribution capacities of this material towards certain environmentally hazardous metal ions are also performed. The material shows good chemical stability towards acidic conditions and exhibits fast elution of exchangeable H(+) ions under neutral conditions. This material shows remarkable selectivity for Ni(II) and on the basis of its Kd value (4×10(2) in 0.01M HClO4) some binary separations of Ni(II) from other metal ions are performed. PMID:23774782

  1. Selective Separation of Arsenic(III) and (V) Ions with Ferric Complex of Chelating Ion-Exchange Resin

    Microsoft Academic Search

    Isao Yoshida; Keihei Ueno; Hiroshi Kobayashi

    1978-01-01

    Trace levels of aqueous arsenic(III) and (V) ions were adsorbed selectively onto the ferric complex of a chelating resin, Uniselec UR-10. The adsorption was markedly dependent upon the pH of the aqueous phase. The distribution ratio and the specific adsorption capacity of arsenic(III) were 23,000 and 0.47 mmole\\/g, respectively, at the optimum pH for the adsorption, 9.2. The corresponding values

  2. Irradiation-induced Ag-colloid formation in ion-exchanged soda-lime glass

    NASA Astrophysics Data System (ADS)

    Caccavale, F.; De Marchi, G.; Gonella, F.; Mazzoldi, P.; Meneghini, C.; Quaranta, A.; Arnold, G. W.; Battaglin, G.; Mattei, G.

    1995-03-01

    Ion-exchanged glass samples were obtained by immersing soda-lime slides in molten salt baths of molar concentration in the range 1-20% AgNO 3 in NaNO 3, at temperatures varying from 320 to 350°C, and processing times of the order of a few minutes. Irradiations of exchanged samples were subsequently performed by using H +m, He +, N + ions at different energies in order to obtain comparable projected ranges. The fluence was varied between 5 × 10 15 and 2 × 10 17 ions/cm 2. Most of the samples were treated at current densities lower than 2 ?A/cm 2, in order to avoid heating effects. Some samples were irradiated with 4 keV electrons, corresponding to a range of 250 nm. The formation of nanoclusters of radii in the range 1-10 nm has been observed after irradiation, depending on the treatment conditions. The precipitation process is governed by the electronic energy deposition of incident particles. The most desirable results are obtained for helium implants. The process was characterized by the use of Secondary Ion Mass Spectrometry (SIMS) and nuclear techniques (Rutherford Backscattering (RBS), Nuclear Reactions (NRA)), in order to determine concentration-depth profiles and by optical absorption and Transmission Electron Microscopy (TEM) measurements for the silver nanoclusters detection and size evaluation.

  3. Nuclear quantum effects in water exchange around lithium and fluoride ions.

    PubMed

    Wilkins, David M; Manolopoulos, David E; Dang, Liem X

    2015-02-14

    We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the exchange processes are unaffected by quantization, so a classical description of these reactions gives qualitatively correct and quantitatively reasonable results. We also find that the quantum effects in solutions of lithium are larger than in solutions of fluoride. This is partly due to the stronger interaction of lithium with water molecules, partly due to the lighter mass of lithium and partly due to competing quantum effects in the hydration of fluoride, which are absent in the hydration of lithium. PMID:25681925

  4. Ion-exchange polymer nanofibers for enhanced osteogenic differentiation of stem cells and ectopic bone formation.

    PubMed

    Shabani, Iman; Haddadi-Asl, Vahid; Soleimani, Masoud; Seyedjafari, Ehsan; Hashemi, Seyed Mahmoud

    2014-01-01

    Nanofibrous scaffolds with specific modifications have shown promising potential for bone tissue engineering applications. In the present study, poly(ether sulfone) (PES) and sulfonated PES (SPES) nanofibers were fabricated via electrospinning. Calcium ions were then incorporated in SPES by immersion in a Ca(OH)2 solution. The calcium-ion-exchanged SPES (Ca-SPES), PES, and SPES nanofibers were characterized and then evaluated for their osteogenic capacity: both in vitro using stem cell culture and in vivo after subcutaneous implantation in mice. After 7 days of immersion in simulated body fluid, the formation of an apatite layer was only observed on Ca-SPES nanofibers. According to the MTT results, an increasing stem cell population was detected on all scaffolds during the period of study. Using real-time reverse transcriptase-polymerase chain reaction, alkaline phosphatase activity, and calcium content assays, it was demonstrated that the osteogenic differentiation of stem cells was higher on Ca-SPES scaffolds in comparison with PES and SPES nanofibers. Interestingly, Ca-SPES scaffolds were shown to induce ectopic bone formation after 12 weeks of subcutaneous implantation in mice. This was confirmed by mineralization and the production of collagen fibers using van Kossa and Masson's trichrome staining, respectively. Taken together, it was demonstrated that the incorporation of calcium ions into the ion-exchange nanofibrous scaffolds not only gives them the ability to enhance osteogenic differentiation of stem cells in vitro but also to induce ectopic bone formation in vivo. PMID:24328219

  5. Removal and recovery of nutrients by ion exchange from high rate membrane bio-reactor (MBR) effluent

    Microsoft Academic Search

    M. A. H. Johir; J. George; S. Vigneswaran; J. Kandasamy; A. Grasmick

    2011-01-01

    In this study a membrane bioreactor (MBR) with ion-exchange as post-treatment was investigated for organic removal and nutrient recovery. The MBR was operated at a short HRT of 4h in order to mainly remove organic carbon. This was followed by an ion-exchange process to remove and later recover the nitrogen and phosphorus from the MBR effluent. The increase in membrane

  6. Study of Nonlinear Wave Propagation Theory. III. Removing Heavy Metals from Wastewater by Ion-Exchange Process

    Microsoft Academic Search

    JIA-MING CHERN; FANG-CHING CHANG

    2000-01-01

    The nonlinear wave propagation theory has been applied to predict the breakthrough and regeneration curves of ion-exchange columns for heavy metal removal. Batch experimental tests using IRC-718 cationic resin were conducted to obtain the ion-exchange equilibria of H\\/Cu and H\\/Ni systems, and column tests were conducted to obtain the breakthrough and regeneration curves under various operating conditions. The batch experimental

  7. Investigation of the ion exchange equilibrium between NA+, Ca++, Mg++, and a sulfonated polystyrene resin at various concentrations 

    E-print Network

    McIlhenny, William Franklin

    1958-01-01

    INVESTIGATiON OF THE ION EXCHANGE EQUILIBRIUM BETWEEN Na , Ca++, Mg++, AND A SULFONATED POLYSTYRENE RESIN AT VARIOUS CONCENTRATIONS A THESIS BY WILLIAM FRANKLIN McILHENNY Submitted to the Graduate School of the Agricultural and Mechanical... College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE January 1958 MaJor Subject: Chemical Engineering INVESTIGATION OF THE ION EXCHANGE EQUILIBRIUM BFTWEEN Na+, Ca++ Mg++ AND A SULFONATED POLYSTYRENE RESIN...

  8. Ion temperature by charge exchange neutral analysis from vertical sightlines on the Tokamak Fusion Test Reactor

    SciTech Connect

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

    1987-12-01

    The Fokker-Planck code FPPRF is used to calculate the expected deuterium charge exchange flux along vertical sighlines from TFTR neutral-beam-injected discharges. The feasibility of obtaining central ion temperature measurements by fitting the spectra obtained from these sightlines at two energy regions--above the highest neutral beam injection energy (> 100 keV) and from 20-80 keV--is investigated. It is demonstrated that the central ion temperature can be obtained from the central vertical slightline for fitting the high energy data. The deuterium neutral particle flux energy distribution below the neutral beam injection energy is insentive to the code input ion temperature, however. 6 refs., 12 figs., 1 tab.

  9. Transition Path Sampling of Water Exchange Rates and Mechanisms around Aqueous Ions

    SciTech Connect

    Kerisit, Sebastien N.; Rosso, Kevin M.

    2009-09-21

    The rates and mechanisms of water exchange around two aqueous ions, namely, Na+ and Fe2+, have been determined using transition path sampling. In particular, the pressure dependence of the water exchange rates was computed to determine activation volumes. A common approach for calculating water exchange rates, the reactive flux method, was also employed and the two methods were compared. The water exchange rate around Na+ is fast enough to be calculated by direct molecular dynamics simulations, thus providing a reference for comparison. The transition path sampling approach yielded more accurate rates, although both approaches predicted activation volumes of +2.6 cm3·mol-1, in agreement with the direct simulation results. The only previously determined activation volume for Na+ is from a theoretical estimation (Spångberg, D.; Wojcik, M.; Hermansson, K. Chem. Phys. Lett. 1997, 276, 114-121) and differs in sign and magnitude from that calculated in this work. We show that this is due to an overestimation of the sodium hydration energy in the previous model. For water exchange around Fe2+, transition path sampling predicts an activation volume of +3.8 cm3.mol?1, in excellent agreement with available experimental data. The reactive flux approach, however, failed to identify the transition state and predicted the opposite pressure dependence of the rate as a result. Analysis of the reactive trajectories obtained with the transition path sampling approach suggests that the Fe2+ exchange reaction takes place via an associative interchange mechanism, which goes against the conventional mechanistic interpretation of a positive activation volume. Collectively, considerable insight obtains not only for the exchange rates and mechanisms for Na+ and Fe2+, but also for identifying the most robust modeling strategy for these purposes.

  10. Temperatures of individual ion species and heating due to charge exchange in the ionosphere of Venus

    NASA Astrophysics Data System (ADS)

    Kim, J.; Nagy, A. F.; Cravens, T. E.; Shinagawa, H.

    1990-05-01

    The coupled electron and multispecies ion energy equations were solved for daytime conditions in the Venus ionosphere. The heating rates due to charge exchange between hot oxygen atoms and thermal oxygen ions were calculated and incorporated into the energy equations. The combination of the traditional EUV heating and this hot oxygen energy source leads to calculated electron and individual ion temperatures significantly lower than the measured values during solar cycle maximum conditions. Calculations were also carried out for solar cycle minimum conditions, which led to considerably lower temperatures; no data are available which would allow direct comparisons of these results with measurements. In order to obtain calculated temperature values consistent with the observed ones, for solar cycle maximum conditions, topside heat inflows into the ion and electron gases have to be introduced or the thermal conductivity must be reduced by considering the effect of steady and fluctuating magnetic fields, as was done in previous studies. The addition of hot oxygen heating leads to minor increases in the calculated ion temperatures except for the case of reduced thermal conductivities. Separate temperatures were calculated for each ion species for a number of different conditions and in general the differences were found to be relatively small.

  11. Gaseous anion chemistry. Hydrogen-deuterium exchange in mono- and dialcohol alkoxide ions: ionization reactions in dialcohols

    SciTech Connect

    Lloyd, J.R.; Agosta, W.C.; Field, F.H.

    1980-08-15

    The subject of this work is H-D exchange in certain gaseous anions using D/sub 2/ as the exchanging agent. The anions involved are produced from ethylene glycol, 1,3-propanediol, 1,4-butanediol, ethanol, 1-propanol, and 1-butanol. Spectra and postulated ionization reactions for these mono- and dialcohols are given. Hydrogen-deuterium exchange occurs in the (M - 1)/sup -/ and (2M - 1)/sup -/ ions of ethylene glycol, 1,3-propanediol, and 1,4-butanediol. The amount of exchange occurring is 3-8 times greater in (2M - 1)/sup -/ than in (M - 1)/sup -/. The amount of H-D exchange occurring in ethanol, 1-propanol, and 1-butanol is small or zero in the (2M - 1)/sup -/ ions and in the (M - 1)/sup -/ ion for 1-butanol (the only (M - 1)/sup -/ ion which could be examined experimentally). The amount of exchange occurring in the (2M - 1)/sup -/ and (M - 1)/sup -/ ions from ethylene glycol is not affected by the total pressure or composition of the reaction mixture in the ionization chamber of the mass spectrometer. A novel hydrogen-bridging mechanism is suggested to account for the observed exchange occurring in the dialcohols.

  12. Measurement of charge exchange cross sections for highly charged xenon and thorium ions with molecular hydrogen in a Penning Ion Trap

    SciTech Connect

    Weinberg, G.M.

    1995-12-01

    Highly charged xenon (35+ to 46+) and thorium (72+ to 79+) ions were produced in an Electron Beam Ion Trap (EBIT). The ions were extracted from EBIT in a short pulse. Ions of one charge state were selected using an electromagnet. The ions were recaptured at low energy in a cryogenic Penning trap (RETRAP). As the ions captured electrons from molecular hydrogen, populations of the various charge states were obtained by measuring the image currents induced by the ions on the electrodes of the trap. Data on the number of ions in each charge state vs. time were compared to theoretical rate equations in order to determine the average charge exchange rates. These rates were compared to charge exchange rates of an ion with a known charge exchange cross section (Ar{sup 11+}) measured in a similar manner in order to determine the average charge exchange cross sections for the highly charged ions. The energy of interaction between the highly charged ions and hydrogen was estimated to be 4 eV in the center of mass frame. The mean charge exchange cross sections were 9 {times} 10{sup {minus}14} cm{sup 2} for Xe{sup 43+} to Xe{sup 46+} and 2 {times} 10{sup {minus}13} cm{sup 2} for Th{sup 73+} to Th{sup 79+}. Double capture was approximately 20--25% of the total for both xenon and thorium. A fit indicated that the cross sections were approximately proportional to q. This is consistent with a linear dependence of cross section on q within the measurement uncertainties.

  13. Synthesis of Single-Crystalline Niobate Nanorods via Ion-Exchange Based on Molten-Salt Reaction

    E-print Network

    Wang, Zhong L.

    Synthesis of Single-Crystalline Niobate Nanorods via Ion-Exchange Based on Molten-Salt Reaction by employing hydrothermal reaction2 or templates,3 molten-salt syn- thesis,4 and composite- exchange approach for the synthesis of single-crystal sodium and calcium niobates nanorods based on molten-salt

  14. Radiation effects on Dowex MSC1, Amberlite 252, and Duolite C-264 ion exchange resins. [Gamma rays

    Microsoft Academic Search

    A. R. Kazanjian; J. R. Stevens

    1983-01-01

    The radiation effects on three new cation exchange resins were investigated. The resins were Dowex MSC-1, Amberlite 252, and Duolite C-264. The properties examined were ion exchange capacity, moisture content, plutonium loading and elution characteristics, thermal stability, and gas generation. There were some differences in the radiation effects on these properties but the overall radiation stability was considered to be

  15. Simple and versatile operational fractionation of Fe and Zn in dietary products by solid phase extraction on ion exchange resins

    Microsoft Academic Search

    P. Pohl; B. Prusisz

    2007-01-01

    A simple and versatile protocol, based on use of solid phase extraction on strong ion exchangers and off-line detection by flame atomic absorption spectrometry, was devised to fractionate iron and zinc in common dietary food and beverages products, i.e., bee honeys, fruit juices and tea infusions. In the procedure proposed, cation exchanger Dowex 50Wx4 and anion exchanger Dowex 1x4 were

  16. UPTAKE OF METAL IONS BY A NEW CHELATING ION EXCHANGE RESIN. PART 3: PROTONATION CONSTANTS VIA POTENTIOMETRIC TITRATION AND SOLID STATE 31P NMR SPECTROSCOPY

    Microsoft Academic Search

    K. L. Nash; P. G. Rickert; J. V. Muntean; S. D. Alexandratos

    1994-01-01

    A new chelating ion exchange resin which incorporates methylenediphosphonate, carboxylate, and sulfonate functional groups in a polystyrene-divinylbenzene matrix has been prepared. This resin exhibits exceptionally high affinity for polyvalent cations even from moderately acidic aqueous media. Metal ion coordination occurs primarily at the diphosphonate group with the secondary binding sites contributing to charge neutralization when necessary and possible, and to

  17. The ratio of the single and double scattering intensities in ion scattering spectroscopy as a quantitative measure of surface structures

    Microsoft Academic Search

    A. J. Algra; S. B. Luitjens; H. Borggreve; E. P. Th. M. Suurmeijer; A. L. Boers

    1982-01-01

    The ratio R of the intensities of the single and double scattering peaks observed in Ion Scattering Spectroscopy has been determined as a function of several experimental parameters. If all particles scattered through a certain scattering angle are detected with a time of flight spectrometer or when alkali ions are used as primary particles then the absolute value of R

  18. Development of the gas puff charge exchange recombination spectroscopy (GP-CXRS) technique for ion measurements in the plasma edge

    SciTech Connect

    Churchill, R. M.; Theiler, C.; Lipschultz, B. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)] [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Dux, R.; Pütterich, T.; Viezzer, E. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany)] [Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstrasse 2, D-85748 Garching (Germany); Collaboration: Alcator C-Mod Team; ASDEX Upgrade Team

    2013-09-15

    A novel charge-exchange recombination spectroscopy (CXRS) diagnostic method is presented, which uses a simple thermal gas puff for its donor neutral source, instead of the typical high-energy neutral beam. This diagnostic, named gas puff CXRS (GP-CXRS), is used to measure ion density, velocity, and temperature in the tokamak edge/pedestal region with excellent signal-background ratios, and has a number of advantages to conventional beam-based CXRS systems. Here we develop the physics basis for GP-CXRS, including the neutral transport, the charge-exchange process at low energies, and effects of energy-dependent rate coefficients on the measurements. The GP-CXRS hardware setup is described on two separate tokamaks, Alcator C-Mod and ASDEX Upgrade. Measured spectra and profiles are also presented. Profile comparisons of GP-CXRS and a beam based CXRS system show good agreement. Emphasis is given throughout to describing guiding principles for users interested in applying the GP-CXRS diagnostic technique.

  19. Clinical oxygen enhancement ratio of tumors in carbon ion radiotherapy: the influence of local oxygenation changes.

    PubMed

    Antonovic, Laura; Lindblom, Emely; Dasu, Alexandru; Bassler, Niels; Furusawa, Yoshiya; Toma-Dasu, Iuliana

    2014-09-01

    The effect of carbon ion radiotherapy on hypoxic tumors has recently been questioned because of low linear energy transfer (LET) values in the spread-out Bragg peak (SOBP). The aim of this study was to investigate the role of hypoxia and local oxygenation changes (LOCs) in fractionated carbon ion radiotherapy. Three-dimensional tumors with hypoxic subvolumes were simulated assuming interfraction LOCs. Different fractionations were applied using a clinically relevant treatment plan with a known LET distribution. The surviving fraction was calculated, taking oxygen tension, dose and LET into account, using the repairable-conditionally repairable (RCR) damage model with parameters for human salivary gland tumor cells. The clinical oxygen enhancement ratio (OER) was defined as the ratio of doses required for a tumor control probability of 50% for hypoxic and well-oxygenated tumors. The resulting OER was well above unity for all fractionations. For the hypoxic tumor, the tumor control probability was considerably higher if LOCs were assumed, rather than static oxygenation. The beneficial effect of LOCs increased with the number of fractions. However, for very low fraction doses, the improvement related to LOCs did not compensate for the increase in total dose required for tumor control. In conclusion, our results suggest that hypoxia can influence the outcome of carbon ion radiotherapy because of the non-negligible oxygen effect at the low LETs in the SOBP. However, if LOCs occur, a relatively high level of tumor control probability is achievable with a large range of fractionation schedules for tumors with hypoxic subvolumes, but both hyperfractionation and hypofractionation should be pursued with caution. PMID:24728013

  20. Ion-Exchange Membranes Prepared Using Layer-by-Layer Polyelectrolyte Deposition.

    PubMed

    Liu, Guanqing; Dotzauer, David M; Bruening, Merlin L

    2010-05-15

    Layer-by-layer polyelectrolyte adsorption in porous polymeric membranes provides a simple way to create ion-exchange sites without greatly decreasing hydraulic permeability (<20% reduction in permeability). At 80% breakthrough, membranes coated with 3-bilayer poly(styrene sulfonate) (PSS)/polyethyleneimine (PEI) films bind 37±6 mg of negatively charged Au colloids per mL of membrane volume. The binding capacity of membranes coated with 1-bilayer films decreases in the order PSS/PEI>PSS/poly(diallyldimethyl ammonium chloride)>PSS/poly(allylamine hydrochloride). Films terminated with a polyanion present cation-exchange sites that bind lysozyme, and the lysozyme-binding capacities of (PSS/PEI)(3)/PSS films increase with the ionic strength of the solution from which the last PSS layer is deposited. Charge screening during deposition of the terminal PSS layer gives rise to a larger number of ion-exchange sites and lysozyme binding capacities as high as 16 mg per mL of membrane. At 10% breakthrough, a stack of 3 membranes binds 3 times as much lysozyme as a single membrane, showing that stacking is an effective way to increase capacity. PMID:20606722

  1. Ion-exchange funneling in thin-film coating modification of heterogeneous electrodialysis membranes.

    PubMed

    Rubinstein, Isaak; Zaltzman, Boris; Pundik, Tamara

    2002-04-01

    Inexpensive highly permselective heterogeneous ion-exchange membranes are prohibitively highly polarizable by a dc current for being used in electrodialysis. According to recent experiments, polarizability of these membranes may be considerably reduced by casting on their surface a thin layer of crosslinked polyelectrolyte, slightly charged with the same sign as the membrane's charge. The present paper is concerned with this effect. Concentration polarization of a permselective heterogeneous ion-exchange membrane by a dc current is determined by geometric factors, such as, the typical size of the ion-permeable "gates" at the membrane surface relative to the separation distance between them and the diffusion layer thickness. The main quantitative characteristic of polarizability of a heterogeneous membrane is its voltage/current curve with its typical saturation at the limiting current, which is lower than that for a homogeneous membrane. In the present study we modify the previously developed two-dimensional model of ionic transport in a diffusion layer at a heterogeneous ion-exchange membrane by including into consideration a homogeneous ion-exchange layer adjacent to the membrane surface. A numerical solution of the respective boundary value problem shows that, indeed, adding even a very thin and weakly charged layer of this kind increases the value of the limiting current, to that of a homogeneous membrane. What differs, for different values of coating parameters, is the form of the voltage/current curves but not the value of the limiting current, namely: the thinner is the coating and the lower the fixed charge density in it, the "slower" is the approach of the limiting current. In order to explain this feature, a simple limiting model of modified membrane is derived from the original two-layer model. In this limiting model, asymptotically valid for a thin coating, solution of the ionic transport equations in it is replaced, via a suitable averaging procedure, by a single nonlinear boundary condition for the membrane/solution interface. Rigorous analysis shows that the aforementioned property of the limiting current is an exact mathematical feature of this limiting model, when the underlying physical phenomenon is the funneling of counterions by the charged layer from the impermeable parts of the membrane towards the "entrance gates." An approximate analytical solution, developed for this model, compares well with the exact numerical one. PMID:12005829

  2. Ag-doped 45S5 Bioglass®-based bone scaffolds by molten salt ion exchange: processing and characterisation.

    PubMed

    Newby, P J; El-Gendy, R; Kirkham, J; Yang, X B; Thompson, I D; Boccaccini, A R

    2011-03-01

    There is increasing interest in developing scaffolds with therapeutic and antibacterial potential for bone tissue engineering. Silver is a proven antibacterial agent which bacteria such as MRSA have little or no defense against. Using an ion exchange method, silver ions have been introduced into 45S5 Bioglass(®) based scaffolds that were fabricated using the foam replication technique. This technique allows the introduction of Ag(+) ions onto the surface of the scaffold without compromising the scaffold bioactivity and other physical properties such as porosity. Controlling the amount of Ag(+) ions introduced onto the surface of the scaffold was achieved by tailoring the ion exchange parameters to fabricate samples with repeatable and predictable Ag(+) ion release behavior. In vitro studies in simulated body fluid were carried out to ensure that the scaffolds maintained their bioactivity after the introduction of Ag(+) ions. It was also shown that the addition of low concentrations (2000:1 w/w) of silver ions supported the attachment and viability of human periodontal ligament stromal cells on the 3D scaffolds. This work has thus confirmed ion exchange as an effective technique to introduce Ag(+) ions into 45S5 Bioglass(®) scaffolds without compromising the basic properties of 45S5 Bioglass(®) which are required for applications in bone tissue engineering. PMID:21293911

  3. ELECTROMAGNETIC THERMAL INSTABILITY WITH MOMENTUM AND ENERGY EXCHANGE BETWEEN ELECTRONS AND IONS IN GALAXY CLUSTERS

    SciTech Connect

    Nekrasov, Anatoly K., E-mail: nekrassov@t-online.de, E-mail: anekrasov@ifz.ru [Institute of Physics of the Earth, Russian Academy of Sciences, 123995 Moscow (Russian Federation)

    2011-10-01

    Thermal instability in an electron-ion magnetized plasma, which is relevant in the intragalactic medium of galaxy clusters, solar corona, and other two-component plasma objects, is investigated. We apply the multicomponent plasma approach where the dynamics of all species are considered separately through electric field perturbations. General expressions for the dynamical variables obtained in this paper can be applied over a wide range of astrophysical and laboratory plasmas also containing neutrals and dust grains. We assume that background temperatures of electrons and ions are different and include the energy exchange in thermal equations for electrons and ions along with the collisional momentum exchange in equations of motion. We take into account the dependence of collision frequency on density and temperature perturbations. The cooling-heating functions are taken for both electrons and ions. A condensation mode of thermal instability has been studied in the fast sound speed limit. We derive a new dispersion relation including different electron and ion cooling-heating functions and other effects mentioned above and find its simple solutions for growth rates in limiting cases. We show that the perturbations have an electromagnetic nature and demonstrate the crucial role of the electric field perturbation along the background magnetic field in the fast sound speed limit. We find that at the conditions under consideration, condensation must occur along the magnetic field while the transverse scale sizes can be both larger and smaller than the longitudinal ones. The results obtained can be useful for interpretating observations of dense cold regions in astrophysical objects.

  4. Role of metal ion incorporation in ion exchange resin on the selectivity of fluoride

    Microsoft Academic Search

    Natrayasamy Viswanathan; S. Meenakshi

    2009-01-01

    Indion FR 10 resin has sulphonic acid functional group (H+ form) possesses appreciable defluoridation capacity (DC) and its DC has been enhanced by chemical modification into Na+ and Al3+ forms by loading respective metal ions in H+ form of resin. The DCs of Na+ and Al3+ forms were found to be 445 and 478mgF?\\/kg, respectively, whereas the DC of H+

  5. Online deuterium hydrogen exchange and protein digestion coupled with ion mobility spectrometry and tandem mass spectrometry.

    PubMed

    Donohoe, Gregory C; Arndt, James R; Valentine, Stephen J

    2015-05-19

    Online deuterium hydrogen exchange (DHX) and pepsin digestion (PD) is demonstrated using drift tube ion mobility spectrometry (DTIMS) coupled with linear ion trap (LTQ) mass spectrometry (MS) with electron transfer dissociation (ETD) capabilities. DHX of deuterated ubiquitin, followed by subsequent quenching and digestion, is performed within ?60 s, yielding 100% peptide sequence coverage. The high reproducibility of the IMS separation allows spectral feature matching between two-dimensional IMS-MS datasets (undeuterated and deuterated) without the need for dataset alignment. Extracted ion drift time distributions (XIDTDs) of deuterated peptic peptides are mobility-matched to corresponding XIDTDs of undeuterated peptic peptides that were identified using collision-induced dissociation (CID). Matching XIDTDs allows a straightforward identification and deuterium retention evaluation for labeled peptides. Aside from the mobility separation, the ion trapping capabilities of the LTQ, combined with ETD, are demonstrated to provide single-residue resolution. Deuterium retention for the c- series ions across residues M(1)-L(15) and N(25)-R(42) are in good agreement with the known secondary structural elements within ubiquitin. PMID:25893550

  6. Charge exchange of low-energy ions in thin carbon foils

    NASA Technical Reports Server (NTRS)

    Buergi, Alfred; Oetliker, Michael; Bochsler, Peter; Geiss, Johannes; Coplan, Michael A.

    1990-01-01

    In order to calibrate a time-of-flight mass spectrometer which is to be flown in the solar wind, the charge exchange properties of low-energy ions in thin carbon foils have been investigated. Incident ions of He, C, N, O, Ne, and Ar with energies in the range 0.5-2 keV/nucleon have been used to measure charge-state distribution, residual energy, and angular distribution after transmission through thin (1-6 microgram/sq cm) carbon foils. Within such foils, an equilibrium between ionization and recombination of the projectile is rapidly established, and, consequently, the charge state of the emerging particle depends essentially on its residual velocity. A comparison of the charge exchange properties of Ne-22 with Ne-20 demonstrates that indeed the velocity (and not the energy) of the emerging particle determines its final charge. A comparison of properties of different elements provides an indication of an electron shell effect. Predictions for the energy loss of ions within the carbon foils made with the TRIM code are in good agreement with the experimental results presented in this paper.

  7. Charge exchange of low-energy ions in thin carbon foils

    SciTech Connect

    Buergi, A.; Oetliker, M.; Bochsler, P.; Geiss, J. (Physikalisches lnstitut, University of Bern, 3012 Bern (Switzerland)); Coplan, M.A. (Institute for Physical Science and Technology, University of Maryland, College Park, MD (USA))

    1990-09-15

    In order to calibrate a time-of-flight mass spectrometer which is to be flown in the solar wind we have investigated the charge exchange properties of low-energy ions in thin carbon foils. We have used incident ions of He, C, N, O, Ne, and Ar with energies in the range 0.5--2 keV/nucleon to measure charge-state distribution, residual energy, and angular distribution after transmission through thin (1--6 {mu}g/cm{sup 2} ) carbon foils. Within such foils an equilibrium between ionization and recombination of the projectile is rapidly established and, consequently, the charge state of the emerging particle depends essentially on its residual velocity. A comparison of the charge exchange properties of {sup 22} Ne with {sup 2}{sup 0}Ne demonstrates that indeed the velocity (and not the energy) of the emerging particle determines its final charge. Comparing properties of different elements one observes an indication of an electron shell effect. Predictions for the energy loss of ions within the carbon foils made with the TRIM code (J. F. Ziegler, computer code TRIM-88 (IBM-Research, Yorktown, NY, 1987)) are in good agreement with the experimental results presented in this paper.

  8. Synthesis, structural characterization, and performance evaluation of resorcinol-formaldehyde (R-F) ion-exchange resin

    SciTech Connect

    Hubler, T.L.; Franz, J.A.; Shaw, W.J.; Bryan, S.A.; Hallen, R.T.; Brown, G.N.; Bray, L.A.; Linehan, J.C.

    1995-08-01

    The 177 underground storage tanks at the DOE`s Hanford Site contain an estimated 180 million tons of high-level radioactive wastes. It is desirable to remove and concentrate the highly radioactive fraction of the tank wastes for vitrification. Resorcinol-formaldehyde (R-F) resin, an organic ion-exchange resin with high selectivity and capacity for the cesium ion, which is a candidate ion-exchange material for use in remediation of tank wastes. The report includes information on the structure/function analysis of R-F resin and the synthetic factors that affect performance of the resin. CS-100, a commercially available phenol-formaldehyde (P-F) resin, and currently the baseline ion-exchanger for removal of cesium ion at Hanford, is compared with the R-F resin. The primary structural unit of the R-F resin was determined to consist of a 1,2,3,4-tetrasubstituted resorcinol ring unit while CS-100, was composed mainly of a 1,2,4-trisubstituted ring. CS-100 shows the presence of phenoxy-ether groups, and this may account for the much lower decontamination factor of CS-100 for cesium ion. Curing temperatures for the R-F resin were found to be optimal at 105--130C. At lower temperatures, insufficient curing, hence crosslinking, of the polymer resin occurs and selectivity for cesium drops. Curing at elevated temperatures leads to chemical degradation. Optimal particle size for R-F resin is in the range of 20--50 mesh-sized particles. R-F resin undergoes chemical degradation or oxidation which destroys ion-exchange sites. The ion-exchange sites (hydroxyl groups) are converted to quinones and ketones. CS-100, though it has much lower performance for cesium ion-exchange, is significantly more chemically stable than R-F resin. To gamma radiation, CS-100 is more radiolytically stable than R-F resin.

  9. Statistical evaluation of ion-channel gating models based on distributions of log-likelihood ratios.

    PubMed

    Csanády, László

    2006-05-15

    The distributions of log-likelihood ratios (DeltaLL) obtained from fitting ion-channel dwell-time distributions with nested pairs of gating models (Xi, full model; Xi(R), submodel) were studied both theoretically and using simulated data. When Xi is true, DeltaLL is asymptotically normally distributed with predictable mean and variance that increase linearly with data length (n). When Xi(R) is true and corresponds to a distinct point in full parameter space, DeltaLL is Gamma-distributed (2DeltaLL is chi-square). However, when data generated by an l-component multiexponential distribution are fitted by l+1 components, Xi(R) corresponds to an infinite set of points in parameter space. The distribution of DeltaLL is a mixture of two components, one identically zero, the other approximated by a Gamma-distribution. This empirical distribution of DeltaLL, assuming Xi(R), allows construction of a valid log-likelihood ratio test. The log-likelihood ratio test, the Akaike information criterion, and the Schwarz criterion all produce asymmetrical Type I and II errors and inefficiently recognize Xi, when true, from short datasets. A new decision strategy, which considers both the parameter estimates and DeltaLL, yields more symmetrical errors and a larger discrimination power for small n. These observations are explained by the distributions of DeltaLL when Xi or Xi(R) is true. PMID:16461404

  10. Isobaric yield ratios and the symmetry energy in heavy-ion reactions near the Fermi energy

    SciTech Connect

    Huang, M. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Z. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China); Kowalski, S. [Institute of Physics, Silesia University, Katowice (Poland); Ma, Y. G. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Wada, R.; Hagel, K.; Barbui, M.; Bottosso, C.; Materna, T.; Natowitz, J. B.; Qin, L.; Rodrigues, M. R. D.; Sahu, P. K. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Keutgen, T. [FNRS and IPN, Universite Catholique de Louvain, B-1348 Louvain-Neuve (Belgium); Bonasera, A. [Cyclotron Institute, Texas A and M University, College Station, Texas 77843 (United States); Laboratori Nazionali del Sud, INFN, via Santa Sofia, 62, 95123 Catania (Italy); Wang, J. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

    2010-04-15

    The relative isobaric yields of fragments produced in a series of heavy-ion-induced multifragmentation reactions have been analyzed in the framework of a modified Fisher model, primarily to determine the ratio of the symmetry energy coefficient to the temperature, a{sub sym}/T, as a function of fragment mass A. The extracted values increase from 5 to approx16 as A increases from 9 to 37. These values have been compared to the results of calculations using the antisymmetrized molecular dynamics (AMD) model together with the statistical decay code gemini. The calculated ratios are in good agreement with those extracted from the experiment. In contrast, the values extracted from the ratios of the primary isobars from the AMD model calculation are approx4 to 5 and show little variation with A. This observation indicates that the value of the symmetry energy coefficient derived from final fragment observables may be significantly different than the actual value at the time of fragment formation. The experimentally observed pairing effect is also studied within the same simulations. The Coulomb coefficient is also discussed.

  11. Softening of oil field produced water by ion exchange for alkaline flooding and steam flooding

    SciTech Connect

    Reyes, R.B.

    1983-03-01

    Oil field ''produced'' waters usually contain high hardness, and high dissolved solids along with some alkalinity. The problem of disposing of these waters and the need for huge volumes of water for alkaline water flooding and steam generation for steam floods, necessitate the softening and reinjection of softened produced water. Water for alkaline and steam flooding needs to be softened to almost zero hardness to prevent plugging during injection and to prevent scaling on boiler tubes. Softening of high TDS and high hardness waters requires a very selective resin with high operating capacity such as a weak carboxylic acid-type ion exchange resin. Conventional softening with strong acid resins would not work under these conditions. This paper discusses the different processes in softening oil field produced water. Data obtained in softening varieties of produced waters from different oil fields in California are presented. Performance characteristics of weak cation exchange resins and their chemical regenerant requirements are also discussed.

  12. Domain propagation in He-ion-bombarded magnetic wires with opposite exchange bias

    SciTech Connect

    McCord, Jeffrey; Schaefer, Rudolf; Theis-Broehl, Katharina; Zabel, Hartmut; Schmalhorst, Jan; Hoeink, Volker; Brueckl, Hubert; Weis, Tanja; Engel, Dieter; Ehresmann, Arno [Leibniz Institute for Solid State and Materials Research IFW Dresden, Institute for Metallic Materials, Helmholtzstrasse 20, 01069 Dresden (Germany); Ruhr University Bochum, Institute of Experimental Physics IV, 44780 Bochum (Germany); University of Bielefeld, Department of Thin Films and Nanostructures, 33615 Bielefeld (Germany); Kaiserslautern University of Technology, Department of Physics, 67663 Kaiserslautern (Germany)

    2005-05-15

    Exchange-biased IrMn/CoFe full films are magnetically structured with He-ion bombardment into stripes with antiparallel-aligned loop shift. The patterning results in a two-step magnetization loop corresponding to two regions of oppositely aligned exchange bias. The longitudinal magnetization reversal through head-on domain-wall motion and partial penetration of magnetization from neighboring strips is highly asymmetric involving ripplelike domain structures and incoherent rotation of magnetization. In addition, Neel-wall-like structures with a preferred sense of rotation are formed at the edges of the strips. Along the transverse direction the reversal is dominated by the switching of the magnetic border structures between the strips. Complicated domain patterns are generated under other external field angles.

  13. Effects of Gamma Radiation on Individual and Mixed Ion Exchange Resins

    SciTech Connect

    Baumann, E.W.

    2003-01-06

    The ion exchange resins that are used to deionize moderator in the reactor purification systems may accumulate sufficient radiation dose to damage the resins. This radiation damage would be manifested by: (1) loss of useful exchange capacity of the bed, which is costly since resins from the reactor deionizers are not reused; (2) shrinking or swelling of the resins, which may have some effect on the hydraulic behavior of the beds; (3) release of resin degradation products into the process stream, which pollutes moderator with impurities and precursors of the neutron-induced radioisotopes. This document details results of a laboratory study to determine the magnitude of these three effects by gamma irradiation of individual resins and their mixtures.

  14. STRONTIUM AND ACTINIDE SORPTION BY MST AND MMST UNDER CONDITIONS REVELANT TO THE SMALL COLUMN ION-EXCHANGE PROCESS

    SciTech Connect

    Taylor-Pashow, K.; Hobbs, D.; Poirier, M.

    2011-05-06

    A series of tests were performed to examine the kinetics of Sr and actinide removal by monosodium titanate (MST) and modified monosodium titanate (mMST) under mixing conditions similar to what will be provided in the Small Column Ion Exchange (SCIX) Program. Similar removal kinetics were seen for two different mixing energies, indicating that under these conditions bulk solution transport is not the rate limiting step for Sr and actinide removal. Sr removal was found to be rapid for both MST and mMST, reaching steady-state conditions within six hours. In contrast, at least six weeks is necessary to reach steady-state conditions for Pu with MST. For mMST, steady-state conditions for Pu were achieved within two weeks. The actual contact time required for the SCIX process will depend on starting sorbate concentrations as well as the requirements for the decontaminated salt solution. During testing leaks occurred in both the MST and mMST tests and evidence of potential desorption was observed. The desorption likely occurred as a result of the change in solids to liquid phase ratio that occurred due to the loss of solution. Based on these results, Savannah River National Laboratory (SRNL) recommended additional testing to further study the effect of changing phase ratios on desorption. This testing is currently in progress and results will be documented in a separate report.

  15. Ion-exchange and potentiometric characterization of Al-cystine and Al-cysteine complexes.

    PubMed

    Bohrer, Denise; Polli, Vania Gabbi; Cícero do Nascimento, Paulo; Mendonça, Jean Karlo A; de Carvalho, Leandro Machado; Pomblum, Solange Garcia

    2006-11-01

    The interaction between aluminium and cysteine and cystine was evaluated by means of ion-exchange experiments and potentiometry. Ion-exchange experiments included other ligands with affinity for aluminium and two kinds of resins, either a Na+ -form or an Al3+ -form exchanger. The ability of the ligands to keep aluminium in solution in the presence of the Na+ exchanger or to withdraw it from the Al3+ -form resin was evaluated. Aluminium quantification was carried out by either graphite-furnace or flame atomic absorption spectrometry. Aluminium extraction isotherms were linearised using the Scatchard plot, and stability constants were obtained from the curves' slopes. The experiments showed that the ability of the ligands to withdraw aluminium from the Al3+ -form resin increased following the order cysteine < oxalate < citrate = cystine < nitrilotriacetic acid < ethylenediaminetetraacetic acid. Potentiometric titrations, carried out in aqueous solution with constant ionic strength and temperature, showed that the predominant species in solution have a metal-ligand proportion of 1:1 for both amino acids. The main species are Al(OH)3L, with log K of 6.2 for cysteine, and AlL and Al(OH)L, with log K of 10.3 and 1.7, respectively, for cystine. Stability constants obtained from the Scatchard plots showed a linear correlation with the stability constants obtained by potentiometry for cystine and cysteine in this work and those collected from the literature for the other ligands. These results show that cysteine and cystine extract and maintain aluminium in solution, which may explain elevated concentrations of aluminium in parenteral nutrition solutions containing these amino acids. PMID:16932929

  16. Crystalline silicotitanates--new ion exchanger for selective removal of cesium and strontium from radwastes

    SciTech Connect

    Dosch, R.G.; Klavetter, E.A.; Stephens, H.P.; Brown, N.E. [Sandia National Laboratories, Albuquerque, NM (United States); Anthony, R.G. [Texas A& M Univ., College Station, TX (United States)

    1996-08-01

    A new class of inorganic ion exchange material called crystalline silicotitanates (CST) has been developed for radioactive waste treatment in a collaborative effort between Sandia National Laboratories and Texas A&M University. The Sandia National Laboratories Laboratory Directed Research and Development program provided the initial funding for this effort and this report summarizes the rapid progress that was achieved. A wide range of compositions were synthesized, evaluated for cesium (Cs) removal efficiency, and a composition called TAM-5 was developed that exhibits high selectivity and affinity for Cs and strontium (Sr). Tests show it can remove parts per million concentrations of Cs{sup +} from highly alkaline, high-sodium, simulated radioactive waste solutions modeled after those at Hanford, Oak Ridge, and Savannah River. In experiments with solutions that simulate highly alkaline Hanford defense wastes, the crystalline silicotitanates exhibit distribution coefficients for Cs{sup +} of greater than 2,000 ml/g, and distribution coefficients greater than 10,000 ml/g for solutions adjusted to a pH between 1 and 10. In addition, the CSTs were found to exhibit distribution coefficients for Sr{sup +} greater than 100,000 ml/g and for plutonium of 2,000 ml/g from simulated Hanford waste. The CST crystal structure was determined and positions of individual atoms identified using x-ray and neutron diffraction. The structural information has permitted identification of the ion exchange sites and provided insights into the strong effect of pH on Cs ion exchange. Information on the synthesis, composition, and structure of CST is considered proprietary and is not discussed in this report.

  17. Kinetics of Ion Exchange on Clay Minerals and Soil: I. Evaluation of Methods1 R. A. OGWADA AND D. L. SPARKS2

    E-print Network

    Sparks, Donald L.

    Kinetics of Ion Exchange on Clay Minerals and Soil: I. Evaluation of Methods1 R. A. OGWADA AND D. L,vermiculite. Ogwada, R.A., and D.L. Sparks. 1986. Kinetics of ion exchangeon clay minerals and soil: I. Evaluation displacement or flow techniques to investigate kinetics of ion exchange on soils and clay minerals (Sparks

  18. Exchange bias studies of NiFe\\/FeMn\\/NiFe trilayer by ion beam etching

    Microsoft Academic Search

    V. K. Sankaranarayanan; D. Y. Kim; S. M. Yoon; C. O. Kim; C. G. Kim

    2005-01-01

    Effect of low energy ion beam etching on exchange bias in NiFe\\/FeMn\\/NiFe \\u000atrilayer is investigated in multilayers prepared by rf magnetron sputtering. \\u000aStepwise etching and magnetization measurement of FeMn layer in an NiFe\\/FeMn \\u000abilayer show increase of bias as etching proceeds and FeMn thickness \\u000adecreases. The bias show a maximum around 7 nm FeMn thickness and then fall \\u000asharply below 5 nm,

  19. Accuracy of a combined ion-exchange/photometric method for determining molybdenum in seawater

    SciTech Connect

    Tikhonova, N.B.; Andreeva, I.Y.; Charykov, A.K.

    1986-05-01

    This paper reports the accuracy of a combined ion-exchange/photometric method for determining molybdenum in seawater by the doubling and addition methods as well as by renormalizing the ideal calibration curve. The method involved preconcentrating the molybdenum in seawater solution on an anionic sorbent (polyacrylonitrile fiber modified with polyepoxyamine) and finishing by photometric determination using bromopyrogallol red and cetyltrimethylammonium bromide. It is shown that it is possible to renormalize a calibration curve plotted from pure solutions using constant and proportional components of the systematic error.

  20. Purification of Soybean Phosphatidylcholine Using D113-III Ion Exchange Macroporous Resin Packed Column Chromatography

    Microsoft Academic Search

    Yuanfa Liu; Liang Shan; Xingguo Wang

    2009-01-01

    Ten ion-exchange resins were compared for their abilities to separate soybean phosphatidylcholine (PC). D113-III resin was\\u000a selected for PC purification among ten resins tested. The optimum PC adsorption conditions were: concentration of PC solution,\\u000a 3 mg\\/mL; pH of PC solution, 7.5; and adsorption flow rate, 1 mL\\/min. The optimum PC desorption conditions were: eluent, 95%\\u000a ethanol aqueous solution; and elution flow rate,

  1. Gas generation and bubble formation model for crystalline silicotitanate ion exchange columns

    SciTech Connect

    Hang, T.

    2000-07-19

    The authors developed a transient model to describe the process of gas generation due to radiolysis and bubble formation in crystalline silicotitanate (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. This report summarizes the model development and predictions.

  2. Assessing filtering of mountaintop CO2 mixing ratios for application to inverse models of biosphere-atmosphere carbon exchange

    NASA Astrophysics Data System (ADS)

    Brooks, B.-G. J.; Desai, A. R.; Stephens, B. B.; Bowling, D. R.; Burns, S. P.; Watt, A. S.; Heck, S. L.; Sweeney, C.

    2011-09-01

    There is a widely recognized need to improve our understanding of biosphere-atmosphere carbon exchanges in areas of complex terrain including the United States Mountain West. CO2 fluxes over mountainous terrain are difficult to measure often due to unusual and complicated influences associated with atmospheric transport in complex terrain. Using five years of CO2 mixing ratio observations from the Regional Atmospheric Continuous CO2 Network in the Rocky Mountains (Rocky RACCOON), five statistical (subsetting) filters are used to investigate a range of approaches for identifying regionally representative CO2 mixing ratios. Test results from three filters indicate that subsets based on short-term variance and local CO2 gradients across tower inlet heights retain nine-tenths of the total observations and are able to define representative diurnal variability and seasonal cycles even for difficult-to-model sites where the influence of local fluxes is much larger than regional mixing ratio variations. Test results from two other filters that consider measurements from previous and following days using spline fitting or sliding windows are overly selective. Case study examples showed that even when standardized to common subset sizes these windowing-filters rejected measurements representing synoptic changes in CO2, which suggests that they are not well suited to filtering continental CO2 measurements. We present a novel CO2 lapse rate filter that uses CO2 differences between levels in the model atmosphere to constrain subsets of site measurements that are representative on model scales.

  3. Cometary X-Rays: Line Emission Cross Sections for Multiply Charged Solar Wind Ion Charge Exchange

    SciTech Connect

    Otranto, S; Olson, R E; Beiersdorfer, P

    2006-12-22

    Absolute line emission cross sections are presented for 1 keV/amu charge exchange collisions of multiply charged solar wind ions with H{sub 2}O, H, O, CO{sub 2}, and CO cometary targets. The present calculations are contrasted with available laboratory data. A parameter-free model is used to successfully predict the recently observed x-ray spectra of comet C/LINEAR 1999 S4. We show that the resulting spectrum is extremely sensitive to the time variations of the solar wind composition. Our results suggest that orbiting x-ray satellites may be a viable way to predict the solar wind intensities and composition on the Earth many hours before the ions reach the earth.

  4. Processes of excitation transfer in collisions of metastable atoms with ions: Matrix elements of exchange interaction

    SciTech Connect

    Belyaev, A.K. [Russian State Pedagogical Univ., St. Petersburg (Russian Federation); Stankova, K.S. [Inst. of Solid-State Physics, Sofia (Bulgaria)

    1995-10-01

    The processes of excitation transfer in collisions of metastable singlet and triplet helium atoms and metastable triplet neon atoms with the ground-state krypton, argon, and xenon ions are theoretically studied. Expressions for the many-electron matrix elements of exchange interaction are derived and investigated. The partial cross sections and the rate constants are calculated for the proposed multichannel model. The excited states of heavy inert gas ions are shown to be nonuniformly populated. It is predicted that the processes of collisions with the singlet metastable helium atoms are characterized by considerably smaller parameters than the processes of collisions with the triplet metastable helium atoms. The theory is compared with the available experimental data. 16 refs.

  5. Long-range repulsion of colloids driven by ion exchange and diffusiophoresis

    PubMed Central

    Florea, Daniel; Musa, Sami; Huyghe, Jacques M. R.; Wyss, Hans M.

    2014-01-01

    Interactions between surfaces and particles in aqueous suspension are usually limited to distances smaller than 1 ?m. However, in a range of studies from different disciplines, repulsion of particles has been observed over distances of up to hundreds of micrometers, in the absence of any additional external fields. Although a range of hypotheses have been suggested to account for such behavior, the physical mechanisms responsible for the phenomenon still remain unclear. To identify and isolate these mechanisms, we perform detailed experiments on a well-defined experimental system, using a setup that minimizes the effects of gravity and convection. Our experiments clearly indicate that the observed long-range repulsion is driven by a combination of ion exchange, ion diffusion, and diffusiophoresis. We develop a simple model that accounts for our data; this description is expected to be directly applicable to a wide range of systems exhibiting similar long-range forces. PMID:24748113

  6. Neutron spectroscopy as a fuel ion ratio diagnostic: Lessons from JET and prospects for ITERa)

    NASA Astrophysics Data System (ADS)

    Ericsson, G.; Conroy, S.; Gatu Johnson, M.; Andersson Sundén, E.; Cecconello, M.; Eriksson, J.; Hellesen, C.; Sangaroon, S.; Weiszflog, M.; Jet Efda Contributors

    2010-10-01

    The determination of the fuel ion ratio nt/nd in ITER is required at a precision of 20%, time resolution of 100 ms, spatial resolution of a/10, and over a range of 0.01ion temperatures Ti>6 keV and for nT/nD<0.6. A crucial issue is the signal-to-background situation in the measurement of the weak 2.5 MeV emission from DD reactions in the presence of a background of scattered 14 MeV DT neutrons. Important experimental input and corroboration for this assessment are presented from the time-of-flight neutron spectrometer at JET where the presence of a strong component of backscattered neutrons is observed. Neutron emission components on ITER due to beam-thermal and tritium-tritium reactions can further enhance the prospects for NES.

  7. Neutron spectroscopy as a fuel ion ratio diagnostic: Lessons from JET and prospects for ITER

    SciTech Connect

    Ericsson, G.; Conroy, S.; Gatu Johnson, M.; Andersson Sunden, E.; Cecconello, M.; Eriksson, J.; Hellesen, C.; Sangaroon, S.; Weiszflog, M. [Department of Physics and Astronomy, Uppsala University (EURATOM-VR Association), SE-75120 Uppsala (Sweden); Collaboration: JET EFDA Contributors

    2010-10-15

    The determination of the fuel ion ratio n{sub t}/n{sub d} in ITER is required at a precision of 20%, time resolution of 100 ms, spatial resolution of a/10, and over a range of 0.01ion temperatures T{sub i}>6 keV and for n{sub T}/n{sub D}<0.6. A crucial issue is the signal-to-background situation in the measurement of the weak 2.5 MeV emission from DD reactions in the presence of a background of scattered 14 MeV DT neutrons. Important experimental input and corroboration for this assessment are presented from the time-of-flight neutron spectrometer at JET where the presence of a strong component of backscattered neutrons is observed. Neutron emission components on ITER due to beam-thermal and tritium-tritium reactions can further enhance the prospects for NES.

  8. Experimental study of convective exchange in a low aspect ratio perforation: Application to cooling of multiperforated wall

    SciTech Connect

    Nguyen, Phu Hung [Dept. Machine Hydraulique et Aeronautique de l'Instituts Polytechnique de Ha Noi. No. 1 DAI Co Viet-Hai ba Trung, Hanoi (Viet Nam); Dorignac, Eva [Laboratoire d'Etudes Thermiques (UMR 6608), Universite de Poitiers, 86961 Futuroscope Chasseneuil (France)

    2008-10-15

    This work presents an experimental study pertaining to convective transfer in pipes with a square-edged inlet simulating the perforation of a multiperforated wall. The experiments were performed for a range of Reynolds numbers from 3000 to 35,000 and an aspect ratio from 2 to 8. The results achieved have allowed us to characterize the different flow areas within the pipe: takeoff, landing, and developed; they have also enabled us to highlight the influence of aerothermic (Re) and geometric (l/d, type of inlet and number of perforations) parameters. We are likewise proposing correlations allowing for determination of the convective exchange coefficient from preliminarily underscored characteristic points (maximum, minimum and established) in the perforation. (author)

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

    SciTech Connect

    Tusa, Esko; Harjula, Risto; Lehto, Jukka

    2003-02-25

    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 possible to reduce the volume of radioactive waste dramatically. On the other hand, only a small volume of highly selective material is required in applications, which makes it possible to design totally new types of compact treatment systems. The major benefit of selective ion exchange media comes from the very large volume reduction of radioactive waste in final disposal. It is also possible to save in investment costs, because small ion exchanger volumes can be used and handled in a very small facility. This paper describes different applications of these highly selective ion exchangers, both commercial fullscale applications and laboratory tests, to give the idea of their efficiency for different liquids.

  10. Combined AFM nano-machining and reactive ion etching to fabricate high aspect ratio structures.

    PubMed

    Peng, Ping; Shi, Tielin; Liao, Guanglan; Tang, Zirong

    2010-11-01

    In this paper, a new combined method of sub-micron high aspect ratio structure fabrication is developed which can be used for production of nano imprint template. The process includes atomic force microscope (AFM) scratch nano-machining and reactive ion etching (RIE) fabrication. First, 40 nm aluminum film was deposited on the silicon substrate by magnetron sputtering, and then sub-micron grooves were fabricated on the aluminum film by nano scratch using AFM diamond tip. As aluminum film is a good mask for etching silicon, high aspect ratio structures were finally fabricated by RIE process. The fabricated structures were studied by SEM, which shows that the grooves are about 400 nm in width and 5 microm in depth. To obtain sub-micron scale groove structures on the aluminum film, experiments of nanomachining on aluminum films under various machining conditions were conducted. The depths of the grooves fabricated using different scratch loads were also studied by the AFM. The result shows that the material properties of the film/substrate are elastic-plastic following nearly a bilinear law with isotropic strain hardening. Combined AFM nanomachining and RIE process provides a relative lower cost nano fabrication technique than traditional e-beam lithography, and it has a good prospect in nano imprint template fabrication. PMID:21137916

  11. Gas-Phase Hydrogen-Deuterium Exchange Labeling of Select Peptide Ion Conformer Types: a Per-Residue Kinetics Analysis.

    PubMed

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Tafreshian, Amirmahdi; Valentine, Stephen J

    2015-07-01

    The per-residue, gas-phase hydrogen deuterium exchange (HDX) kinetics for individual amino acid residues on selected ion conformer types of the model peptide KKDDDDDIIKIIK have been examined using ion mobility spectrometry (IMS) and HDX-tandem mass spectrometry (MS/MS) techniques. The [M + 4H](4+) ions exhibit two major conformer types with collision cross sections of 418 Å(2) and 446 Å(2); the [M + 3H](3+) ions also yield two different conformer types having collision cross sections of 340 Å(2) and 367 Å(2). Kinetics plots of HDX for individual amino acid residues reveal fast- and slow-exchanging hydrogens. The contributions of each amino acid residue to the overall conformer type rate constant have been estimated. For this peptide, N- and C-terminal K residues exhibit the greatest contributions for all ion conformer types. Interior D and I residues show decreased contributions. Several charge state trends are observed. On average, the D residues of the [M + 3H](3+) ions show faster HDX rate contributions compared with [M + 4H](4+) ions. In contrast the interior I8 and I9 residues show increased accessibility to exchange for the more elongated [M + 4H](4+) ion conformer type. The contribution of each residue to the overall uptake rate showed a good correlation with a residue hydrogen accessibility score model calculated using a distance from charge site and initial incorporation site for nominal structures obtained from molecular dynamic simulations (MDS). Graphical Abstract ?. PMID:25895891

  12. Ion exchange and intercalation properties of layered double hydroxides towards halide anions.

    PubMed

    Costantino, Umberto; Vivani, Riccardo; Bastianini, Maria; Costantino, Ferdinando; Nocchetti, Morena

    2014-08-14

    A layered double hydroxide (LDH) obtained by the urea method, having an empirical formula [Zn(0.61)Al(0.39)(OH)2](CO3)(0.195)·0.50H2O, has been converted into the corresponding chloride form [Zn(0.61)Al(0.39)(OH)2]Cl(0.39)·0.47H2O by making the solid come into contact with a suitable HCl solution. The intercalation of the other halide anions (X(-) = F(-), Br(-), I(-)) via the Cl(-)/X(-) anion exchange has been attained and the respective anion exchange isotherms have been obtained with the batch method. The analysis of the isotherms indicates that the selectivity of LDH towards the halides decreases with the increase of the X(-) ionic radius, the selectivity order being F(-) > Cl(-)? Br(-) > I(-). The CO3(2-)/Cl(-) isotherm has also been reported to highlight the extraordinary selectivity of LDH towards carbonate anions. Samples taken from the isotherms at different exchange degrees were analyzed by X-ray diffraction, thermogravimetry and thermodiffractometry to obtain information about the ion exchange mechanism. The Cl(-)/Br(-) and the reverse Br(-)/Cl(-) exchanges occur with the formation of solid solutions, very likely because of the similar ionic radius of the exchanging anions. In contrast, in the Cl(-)/F(-) and Cl(-)/I(-) exchange, the co-existence of the Cl(-) and F(-) (or I(-)) phases in the same sample was detected, indicating the occurrence of a first order phase transition, in which the starting phase is transformed into the final phase, as the process goes on. The variation of the interlayer distances of ZnAl-X intercalation compounds with the hydration degree has been interpreted with a structural model based on the nesting of the guest species into the trigonal pockets of the brucite-like layer surface. Rietveld refinements of the phases with the maximum F(-), Br(-) and I(-) content were also performed and compared with the above model, giving indications of the arrangement and order/disorder of the halide anions in the interlayer region. PMID:24940938

  13. Acidity field of soils as ion-exchange systems and the diagnostics of genetic soil horizons

    NASA Astrophysics Data System (ADS)

    Kokotov, Yu. A.; Sukhacheva, E. Yu.; Aparin, B. F.

    2014-12-01

    For the comprehensive description of the acidity of a two-phase ion-exchange system, we should analyze two curves of the ionite titration by a strong base in water and salt solutions and find the quantitative relationships between the corresponding pH characteristics. An idea of the three-dimensional field of acidity of ion-exchange systems (the phase space of the soil acidity characteristics) and its three two-dimensional projections is suggested. For soils, three interrelated characteristics—the pH values of the salt and water extracts and the degree of base saturation—can serve as spatial coordinates for the acidity field. Representation of factual data in this field makes it possible to compare and analyze the acidity characteristics of different soils and soil horizons and to determine their specific features. Differentiation of the field into separate volumes allows one to present the data in a discrete form. We have studied the distribution patterns of the groups of soil horizons from Leningrad oblast and other regions of northwestern Russia in the acidity field. The studied samples are grouped in different partially overlapping areas of the projections of the acidity field. The results of this grouping attest to the correctness of the modern classification of Russian soils. A notion of the characteristic soil area in the acidity field is suggested; it can be applied to all the soils with a leaching soil water regime.

  14. Patterned ion exchange membranes for improved power production in microbial reverse-electrodialysis cells

    NASA Astrophysics Data System (ADS)

    Liu, Jia; Geise, Geoffrey M.; Luo, Xi; Hou, Huijie; Zhang, Fang; Feng, Yujie; Hickner, Michael A.; Logan, Bruce E.

    2014-12-01

    Power production in microbial reverse-electrodialysis cells (MRCs) can be limited by the internal resistance of the reverse electrodialysis stack. Typical MRC stacks use non-conductive spacers that block ion transport by the so-called spacer shadow effect. These spacers can be relatively thick compared to the membrane, and thus they increase internal stack resistance due to high solution (ohmic) resistance associated with a thick spacer. New types of patterned anion and cation exchange membranes were developed by casting membranes to create hemispherical protrusions on the membranes, enabling fluid flow between the membranes without the need for a non-conductive spacer. The use of the patterned membrane decreased the MRC stack resistance by ?22 ?, resulting in a 38% increase in power density from 2.50 ± 0.04 W m-2 (non-patterned membrane with a non-conductive spacer) to 3.44 ± 0.02 W m-2 (patterned membrane). The COD removal rate, coulombic efficiency, and energy efficiency of the MRC also increased using the patterned membranes compared to the non-patterned membranes. These results demonstrate that these patterned ion exchange membranes can be used to improve performance of an MRC.

  15. Upgrading fertilizer production wastewater effluent quality for ammonium discharges through ion exchange with clinoptilolite.

    PubMed

    Beler-Baykal, B; Allar, A D

    2008-06-01

    It had previously been shown that ammonium selective natural zeolite clinoptilolite may be used successfully as an ion exchanger for ammonium removal and nitrogen control from domestic wastewater. The process had been reported to be acceptable either by itself alone or as an upgrade. In this work, the possibility of using clinoptilolite for ammonium removal from fertilizer production wastewater was investigated. The fertilizer plant under consideration was rather a non-typical one with a lower ammonium strength than what is normally expected, and a variable effluent concentration. Batch experiments were performed to assess the capacity of clinoptilolite towards ammonium removal from an industrial wastewater at two different pHs. Flow experiments for the characterization of system behavior under continuous feeding conditions at different contact times were conducted for breakthrough analysis. Both real and simulated fertilizer wastewater samples were investigated and the results have shown that the real one may successfully be represented by the simulated one. Experimental results have shown that surface capacities exceeding 14 mg ammonium g(-1) clinoptilolite could be attained, complete removal of ammonium may be achieved with empty bed contact times of 10 min or higher and ion exchange with clinoptilolite could be used successfully to comply with the effluent standards given for the fertilizer plant. PMID:18702292

  16. Modeling Ion-Exchange Processing With Spherical Resins For Cesium Removal

    SciTech Connect

    Hang, T.; Nash, C. A.; Aleman, S. E.

    2012-09-19

    The spherical Resorcinol-Formaldehyde and hypothetical spherical SuperLig(r) 644 ion-exchange resins are evaluated for cesium removal from radioactive waste solutions. Modeling results show that spherical SuperLig(r) 644 reduces column cycling by 50% for high-potassium solutions. Spherical Resorcinol Formaldehyde performs equally well for the lowest-potassium wastes. Less cycling reduces nitric acid usage during resin elution and sodium addition during resin regeneration, therefore, significantly decreasing life-cycle operational costs. A model assessment of the mechanism behind ''cesium bleed'' is also conducted. When a resin bed is eluted, a relatively small amount of cesium remains within resin particles. Cesium can bleed into otherwise decontaminated product in the next loading cycle. The bleed mechanism is shown to be fully isotherm-controlled vs. mass transfer controlled. Knowledge of residual post-elution cesium level and resin isotherm can be utilized to predict rate of cesium bleed in a mostly non-loaded column. Overall, this work demonstrates the versatility of the ion-exchange modeling to study the effects of resin characteristics on processing cycles, rates, and cold chemical consumption. This evaluation justifies further development of a spherical form of the SL644 resin.

  17. MODELING CST ION EXCHANGE FOR CESIUM REMOVAL FROM SCIX BATCHES 1 - 4

    SciTech Connect

    Smith, F.

    2011-04-25

    The objective of this work is, through modeling, to predict the performance of Crystalline Silicotitinate (CST) for the removal of cesium from Small Column Ion Exchange (SCIX) Batches 1-4 (as proposed in Revision 16 of the Liquid Waste System Plan). The scope of this task is specified in Technical Task Request (TTR) 'SCIX Feed Modeling', HLE-TTR-2011-003, which specified using the Zheng, Anthony, Miller (ZAM) code to predict CST isotherms for six given SCIX feed compositions and the VErsatile Reaction and SEparation simulator for Liquid Chromatography (VERSE-LC) code to predict ion-exchange column behavior. The six SCIX feed compositions provided in the TTR represent SCIX Batches 1-4 and Batches 1 and 2 without caustic addition. The study also investigated the sensitivity in column performance to: (1) Flow rates of 5, 10, and 20 gpm with 10 gpm as the nominal flow; and (2) Temperatures of 25, 35, and 45 C with 35 C as the nominal temperature. The isotherms and column predictions presented in this report reflect the expected performance of engineered CST IE-911. This form of CST was used in experiments conducted at the Savannah River National Laboratory (SRNL) that formed the basis for estimating model parameters (Hamm et al., 2002). As has been done previously, the engineered resin capacity is estimated to be 68% of the capacity of particulate CST without binder.

  18. Optimization of a preparative multimodal ion exchange step for purification of a potential malaria vaccine.

    PubMed

    Paul, Jessica; Jensen, Sonja; Dukart, Arthur; Cornelissen, Gesine

    2014-10-31

    In 2000 the implementation of quality by design (QbD) was introduced by the Food and Drug Administration (FDA) and described in the ICH Q8, Q9 and Q10 guidelines. Since that time, systematic optimization strategies for purification of biopharmaceuticals have gained a more important role in industrial process development. In this investigation, the optimization strategy was carried out by adopting design of experiments (DoE) in small scale experiments. A combination method comprising a desalting and a multimodal ion exchange step was used for the experimental runs via the chromatographic system ÄKTA™ avant. The multimodal resin Capto™ adhere was investigated as an alternative to conventional ion exchange and hydrophobic interaction resins for the intermediate purification of the potential malaria vaccine D1M1. The ligands, used in multimodal chromatography, interact with the target molecule in different ways. The multimodal functionality includes the binding of proteins in spite of the ionic strength of the loading material. The target protein binds at specific salt conditions and can be eluted by a step gradient decreasing the pH value and reducing the ionic strength. It is possible to achieve a maximized purity and recovery of the product because degradation products and other contaminants do not bind at specific salt concentrations at which the product still binds to the ligands. PMID:25271026

  19. Production of high resistivity water by electrodialysis. Influence of ion-exchange textiles as conducting spacers

    SciTech Connect

    Laktionov, E.; Dejean, E.; Sandeaux, J.; Sandeaux, R.; Gavach, C.; Pourcelly, G. [CNRS, Montpellier (France). Lab. of Materials and Membrane Processes] [CNRS, Montpellier (France). Lab. of Materials and Membrane Processes

    1999-01-01

    Production of high resistivity water was investigated by electrodialysis (ED) using either inert or conducting spacers. Ion-exchange textiles were used as conducting spacers. Experiments were performed on a preindustrial scale with a pilot consisting of nine two-compartment cells, each membrane having an effective area of 176 cm{sup 2}. Three configurations of the ED stack were investigated for the dilution compartment: EDIT-(2) with a 2-mm thick ion-exchange textile, and ED-(2) or ED-(0.4), with a 0.4-mm thick inert spacer inserted between 2 or 0.4 mm thick dilution compartments, respectively. The textile induces a moderate increase in the pressure drop between the inlet and outlet of the stack. The performances of the different processes were compared under various experimental conditions of pH, nitrogen bubbling throughout the feed solution, flow rate, and current density. The results show that for an inlet conductivity of 10--15 {micro}S/cm, a flow rate of 2.2 {times} 10{sup {minus}5} m{sup 3}/s, and an applied voltage of 80 V, an outlet conductivity of 0.4 {micro}S/cm was obtained with the EDIT process, while no value lower than 5 {micro}S/cm was obtained with the ED process using both stacks.

  20. THERMAL ANALYSIS FOR IN-TANK ION-EXCHANGE COLUMN PROCESS

    SciTech Connect

    Lee, S; Frank02 Smith, F

    2009-01-05

    High Level Waste (HLW) at the Savannah River Site (SRS) is stored in three forms: sludge, saltcake, and supernate. A small column ion-exchange (SCIX) process is being designed to treat dissolved saltcake waste before feeding it to the saltstone facility to be made into grout. The waste is caustic with high concentrations of various sodium salts and lower concentrations of radionuclides. Two cation exchange media being considered are a granular form of crystalline silicotitanate (CST) and a spherical form of resorcinol-formaldehyde (RF) resin. CST is an inorganic material highly selective for cesium that is not elutable. Through this process, radioactive cesium from the salt solution is absorbed into ion exchange media (either CST or RF) which is packed within a flow-through column. A packed column loaded with radioactive cesium generates significant heat from radiolytic decay. If engineering designs cannot handle this thermal load, hot spots may develop locally which could degrade the performance of the ion-exchange media. Performance degradation with regard to cesium removal has been observed between 50 and 80 C for CST [1] and at 65 C for RF resin [2]. In addition, the waste supernate solution will boil around 130 C. If the columns boiled dry, the sorbent material could plug the column and lead to replacement of the entire column module. Alternatively, for organic resins such as RF there is risk of fire at elevated temperatures. The objective of the work is to compute temperature distributions across CST- and RF-packed columns immersed in waste supernate under accident scenarios involving loss of salt solution flow through the beds and, in some cases, loss of coolant system flow. For some cases, temperature distributions are determined as a function of time after the initiation of a given accident scenario and in other cases only the final steady-state temperature distributions are calculated. In general, calculations are conducted to ensure conservative and bounding results for the maximum temperatures achievable using the current baseline column design. This information will assist in SCIX design and facility maintenance.