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Sample records for cs ion exchange

  1. Buried waveguides for passive integrated optics by Cs+ -ion-exchange

    Science.gov (United States)

    Ross, L.; Lilienhof, H.-J.; Holscher, H. W.

    1986-11-01

    Cs4-ion-exchange in glass is compared with the commonly used K+-, Ag+- and T1+-ion-exchange in glass in the process of waveguide fabrication. It will be shown that the Cs4-ion-exchange in the special substrate glass BGG21 represents an alternative method. As in the case of Ag+ AND T14 it is possible to fabricate buried waveguides by a double ion-exchange. The field-assisted ion-exchange is preferred due to the low CO+-ion mobility.

  2. The selective separation of Cs and Sr ion on the inorganic ion-exchanger zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hun Hwee; Min, Byeog Heon [Hoseo University, Taegu (Korea)

    1998-04-01

    This study shows the selective separation of Cs and Sr ion on the inorganic ion-exchanger zeolites such as clinoptilolite, Y-type CBV760, CBV780 and A-type 3A. The selective separation of Cs and Sr on these zeolites was examined using batch and continuous column experiments. For the selective separation of Cs and Sr from a synthetic wastewater, adsorption rate of Cs increased in the order, clinoptilolite> 3A>> CBV760> CBV780, adsorption rate of Sr increased in the other, 3A>> clinoptilolite> CBV760> CBV780. For the clinoptilolite, the adsorption rate of Cs reached about 96 {approx} 98% within 3h. The adsorption rate of Sr on 3A reached about 99% within 3h. (author). 40 refs., 27 figs., 4 tabs.

  3. Crystalline Silicotitanate: a New Type of Ion Exchanger for Cs Removal from Liquid Waste

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The research and developments of a new type of inorganic ion exchanger, crystalline silicotitanate (CST) are reviewed.This material is stable against radiation, and the CST has high selectivity for Cs over Na, K and Rb. It performs well in acidic, neutral, and basic solutions. The results of ion exchange tests show that CST is an excellent candidate for Cs removal from high-level liquid waste.

  4. Separation and immobilization of Sr and Cs contained in acidic media by using inorganic ion-exchangers. Literature survey

    Energy Technology Data Exchange (ETDEWEB)

    Yamagishi, Isao [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    The present study deals with the survey of inorganic ion-exchangers suitable for separation and immobilization of Sr and Cs contained in acidic high-level liquid waste. The stabilities of published waste forms and their preparation processes were evaluated from the standpoint of conversion of exchangers containing Sr and Cs into appropriate waste forms. The essential results are below. (1) For separation and immobilization of Cs, crystalline silicotitanate seems to be the most promising exchanger. Insoluble ferrocyanides and phosphates are not suitable for immobilization without additives. Mordenite is inexpensive and commercially available but it would dissolve in highly acidic media. (2) For selective separation of Sr, there is no promising exchanger up to now. It is necessary either to modify separation condition or to synthesize a novel exchanger. (3) Soluble salts, glasses and ceramics are proposed as a storage or disposal form of separated Sr and Cs. Ceramics sintered by hot-pressing are favorable waste forms of inorganic ion-exchangers but their leachabilities and thermal conductivities are largely influenced by qualities of products. Crystallinity of a sintered exchanger depends on its composition. Exchanges of low Cs contents are often converted into amorphous materials whose chemical stabilities depend on solubilities of components of exchangers. (4) A new exchanger to be synthesized is crystalline and selective toward Sr and Cs. One meq/g is enough for Sr and Cs capacities, which are restricted by thermal and transmutation effects. Composition of the exchanger should be selected from the point of a scenario of separation and disposal. The solubilities of SiO{sub 2}, TiO{sub 2}, ZrO{sub 2}, Nb{sub 2}O{sub 5} and Ta{sub 2}O{sub 5} are low in acidic media and those of Al{sub 2}O{sub 3}, TiO{sub 2} and ZrO{sub 2}, in disposal circumstances. (5) Future works are optimization of separation scheme including development of exchangers, simplification of

  5. Evaluation and comparison of SuperLig{reg_sign} 644, resorcinol-formaldehyde and CS-100 ion exchange materials for the removal of cesium from simulated alkaline supernate

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.N.; Bray, L.A.; Eloviche, R.J. [Pacific Northwest Lab., Richland, WA (United States); Bruening, R.L.; Decker, R.M. [IBC Advanced Technologies, Inc., Provo, UT (United States); Kafka, T.M.; White, L.R. [3M Co., St. Paul, MN (United States)

    1995-03-01

    PNL evaluated three polymeric materials for Cs removal efficiency from a simulated Hanford Neutralized Current Acid Waste (NCAW) supernatant liquid using 200 mL ion exchange columns. Cs loadings (mmole Cs/g resin) were 0.20, 0.18, and 0.039 for Super Lig 644, R-F, and CS-100 (0.045, 0.070, 0.011 mmole Cs/mL resin). Elution of each resin material with 0.5 M HNO{sub 3} required 3.5, 7.0, and 3.2 cv to reach 0.1 C/C{sub 0} for the respective materials, resulting in volume compressions of 27, 20, and 6.9. Peak Cs concentrations during elution was 185, 38.5, and 27.8 C/C{sub 0}. SuperLig 644 had the highest Cs loading per gram in NCAW and the greatest volume compression on aci elution. Because of high density and poor elution, R-F had the highest Cs loading per unit volume and lower volume compression. CS-100, the baseline material for Cs removal at Hanford, was inferior to both SuperLig 644 and R-F in terms of Cs loading and selectivity over sodium.

  6. Ion Exchange and Liquid Column Chromatography.

    Science.gov (United States)

    Walton, Harold F.

    1980-01-01

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

  7. Preliminary flowsheet: Ion exchange process for the separation of cesium from Hanford tank waste using Duolite{trademark} CS-100 resin

    Energy Technology Data Exchange (ETDEWEB)

    Eager, K.M.; Penwell, D.L.; Knutson, B.J.

    1994-12-01

    This preliminary flowsheet document describes an ion exchange process which uses Duolite{trademark} CS-100 resin to remove cesium from Hanford Tank waste. The flowsheet describes one possible equipment configuration, and contains mass balances based on that configuration with feeds of Neutralized Current Acid Waste, and Double Shell Slurry Feed. Process alternatives, unresolved issues, and development needs are discussed which relate to the process.

  8. Leaching of 60Co and 137Cs from spent ion exchange resins in cement–bentonite clay matrix

    Indian Academy of Sciences (India)

    I B Plecas; R S Pavlovic; S D Pavlovic

    2003-12-01

    The leaching rate of 60Co and 137Cs from the spent cation exchange resins in cement–bentonite matrix has been studied. The solidification matrix was a standard Portland cement mixed with 290–350 (kg/m3) spent cation exchange resins, with or without 2–5% of bentonite clay. The leaching rates from the cement–bentonite matrix for 60Co: (4,2–7,0) × 10-5 (cm/d) and 137Cs: (3,2–6,6) × 10-4 (cm/d), after 125 days were measured. From the leaching data the apparent diffusivity of cobalt and cesium in cement–bentonite clay matrix with a waste load of 290–350 (kg/m3) spent cation exchange resins, was measured for 60Co: (1,1–4,0) × 10-6 (cm2/d) and 137Cs: (0,5–2,6) × 10-4 (cm2/d), after 125 days. The results presented in this paper are part of the results obtained in a 20-year mortar and concrete testing project which will influence the design of radioactive waste management for a future Serbian radioactive waste disposal centre.

  9. Competitive binding exchange between alkali metal ions (K+, Rb+, and Cs+) and Na+ ions bound to the dimeric quadruplex [d(G4T4G4)]2: a 23Na and 1H NMR study.

    Science.gov (United States)

    Cesare Marincola, Flaminia; Virno, Ada; Randazzo, Antonio; Mocci, Francesca; Saba, Giuseppe; Lai, Adolfo

    2009-12-01

    A comparative study of the competitive cation exchange between the alkali metal ions K+, Rb+, and Cs+ and the Na+ ions bound to the dimeric quadruplex [d(G4T4G4)]2 was performed in aqueous solution by a combined use of the 23Na and 1H NMR spectroscopy. The titration data confirm the different binding affinities of these ions for the G-quadruplex and, in particular, major differences in the behavior of Cs+ as compared to the other ions were found. Accordingly, Cs+ competes with Na+ only for the binding sites at the quadruplex surface (primarily phosphate groups), while K+ and Rb+ are also able to replace sodium ions located inside the quadruplex. Furthermore, the 1H NMR results relative to the CsCl titration evidence a close approach of Cs+ ions to the phosphate groups in the narrow groove of [d(G4T4G4)]2. Based on a three-site exchange model, the 23Na NMR relaxation data lead to an estimate of the relative binding affinity of Cs+ versus Na+ for the quadruplex surface of 0.5 at 298 K. Comparing this value to those reported in the literature for the surface of the G-quadruplex formed by 5'-guanosinemonophosphate and for the surface of double-helical DNA suggests that topology factors may have an important influence on the cation affinity for the phosphate groups on DNA.

  10. Syntheses and X-ray Powder Structures of K(2)(ZrSi(3)O(9)).H(2)O and Its Ion-Exchanged Phases with Na and Cs.

    Science.gov (United States)

    Poojary, Damodara M.; Bortun, Anatoly I.; Bortun, Lyudmila N.; Clearfield, Abraham

    1997-07-02

    A zirconium trisilicate compound, with composition K(2)ZrSi(3)O(9).H(2)O (1), was prepared under mild hydrothermal conditions and was structurally characterized by using its X-ray powder diffraction data. The compound crystallizes in the space group P2(1)2(1)2(1) with a = 10.2977(2) Å, b = 13.3207(3) Å, c = 7.1956(1) Å, and Z = 4. The asymmetric unit consists of a metal atom, a trisilicate group, and three lattice positions corresponding to two cations and a water oxygen atom. In the structure, the Zr atom is octahedrally coordinated by the six terminal oxygens of the trisilicate group. The trisilicate groups exist as linear chain polymers connected to each other through the Zr atoms. This arrangement leads to channels and cavities in the structure that are occupied by the cations and water molecules. The K(+) ions in compound 1 were exchanged for Cs(+) ions in two steps. In the first case about 50% of the K(+) ions were exchanged to give a compound with composition K(0.9)Cs(1.1)ZrSi(3)O(9).H(2)O (2). Compound 2 was then loaded with additional Cs(+) ions which resulted in a phase K(0.5)Cs(1.5)ZrSi(3)O(9).H(2)O (3). These exchanged phases retain the crystal symmetry of compound 1, but their unit cell dimensions have expanded as a result of large Cs(+) ions replacing the smaller K(+) ions. Structure analyses of the exchanged phases show that the cations found in the cavities of compound 1 are highly selective for Cs(+) ions. A small amount of Cs ions also go to a site in the large channel that is very close to that occupied by the water oxygen in compound 1. In the absence of Cs, this site is filled with water molecules. The second cation found in the channel of 1 is partially occupied by water and K(+) ions. The K(+) ions in compound 1 were completely exchanged for Na(+) ions, and the compound thus obtained, Na(2)ZrSi(3)O(9).H(2)O (4), was treated with Cs(+) ions in a manner similar to that carried out for compound 1. The low Cs(+) ion phase, Na(0.98)Cs(1.02)Zr

  11. Highly Emissive Divalent-Ion-Doped Colloidal CsPb1-xMxBr3 Perovskite Nanocrystals through Cation Exchange.

    Science.gov (United States)

    van der Stam, Ward; Geuchies, Jaco J; Altantzis, Thomas; van den Bos, Karel H W; Meeldijk, Johannes D; Van Aert, Sandra; Bals, Sara; Vanmaekelbergh, Daniel; de Mello Donega, Celso

    2017-03-22

    Colloidal CsPbX3 (X = Br, Cl, and I) perovskite nanocrystals (NCs) have emerged as promising phosphors and solar cell materials due to their remarkable optoelectronic properties. These properties can be tailored by not only controlling the size and shape of the NCs but also postsynthetic composition tuning through topotactic anion exchange. In contrast, property control by cation exchange is still underdeveloped for colloidal CsPbX3 NCs. Here, we present a method that allows partial cation exchange in colloidal CsPbBr3 NCs, whereby Pb(2+) is exchanged for several isovalent cations, resulting in doped CsPb1-xMxBr3 NCs (M= Sn(2+), Cd(2+), and Zn(2+); 0 cells upon incorporation of the guest cations. The partial Pb(2+) for M(2+) exchange leads to a blue-shift of the optical spectra, while maintaining the high photoluminescence quantum yields (>50%), sharp absorption features, and narrow emission of the parent CsPbBr3 NCs. The blue-shift in the optical spectra is attributed to the lattice contraction that accompanies the Pb(2+) for M(2+) cation exchange and is observed to scale linearly with the lattice contraction. This work opens up new possibilities to engineer the properties of halide perovskite NCs, which to date are demonstrated to be the only known system where cation and anion exchange reactions can be sequentially combined while preserving the original NC shape, resulting in compositionally diverse perovskite NCs.

  12. Electrically switched ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Ion exchange equilibrium constants

    CERN Document Server

    Marcus, Y

    2013-01-01

    Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

  14. Highly Emissive Divalent-Ion-Doped Colloidal CsPb1–xMxBr3 Perovskite Nanocrystals through Cation Exchange

    Science.gov (United States)

    2017-01-01

    Colloidal CsPbX3 (X = Br, Cl, and I) perovskite nanocrystals (NCs) have emerged as promising phosphors and solar cell materials due to their remarkable optoelectronic properties. These properties can be tailored by not only controlling the size and shape of the NCs but also postsynthetic composition tuning through topotactic anion exchange. In contrast, property control by cation exchange is still underdeveloped for colloidal CsPbX3 NCs. Here, we present a method that allows partial cation exchange in colloidal CsPbBr3 NCs, whereby Pb2+ is exchanged for several isovalent cations, resulting in doped CsPb1–xMxBr3 NCs (M= Sn2+, Cd2+, and Zn2+; 0 50%), sharp absorption features, and narrow emission of the parent CsPbBr3 NCs. The blue-shift in the optical spectra is attributed to the lattice contraction that accompanies the Pb2+ for M2+ cation exchange and is observed to scale linearly with the lattice contraction. This work opens up new possibilities to engineer the properties of halide perovskite NCs, which to date are demonstrated to be the only known system where cation and anion exchange reactions can be sequentially combined while preserving the original NC shape, resulting in compositionally diverse perovskite NCs. PMID:28260380

  15. Emergence of Bulk CsCl Structure in $(CsCl)_{n}Cs^{+}$ Cluster Ions

    CERN Document Server

    Aguado, A

    2000-01-01

    The emergence of CsCl bulk structure in (CsCl)nCs+ cluster ions is investigated using a mixed quantum-mechanical/semiempirical theoretical approach. We find that rhombic dodecahedral fragments (with bulk CsCl symmetry) are more stable than rock-salt fragments after the completion of the fifth rhombic dodecahedral atomic shell. From this size (n=184) on, a new set of magic numbers should appear in the experimental mass spectra. We also propose another experimental test for this transition, which explicitely involves the electronic structure of the cluster. Finally, we perform more detailed calculations in the size range n=31--33, where recent experimental investigations have found indications of the presence of rhombic dodecahedral (CsCl)32Cs+ isomers in the cluster beams.

  16. Ion exchange phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Bourg, I.C.; Sposito, G.

    2011-05-01

    Ion exchange phenomena involve the population of readily exchangeable ions, the subset of adsorbed solutes that balance the intrinsic surface charge and can be readily replaced by major background electrolyte ions (Sposito, 2008). These phenomena have occupied a central place in soil chemistry research since Way (1850) first showed that potassium uptake by soils resulted in the release of an equal quantity of moles of charge of calcium and magnesium. Ion exchange phenomena are now routinely modeled in studies of soil formation (White et al., 2005), soil reclamation (Kopittke et al., 2006), soil fertilitization (Agbenin and Yakubu, 2006), colloidal dispersion/flocculation (Charlet and Tournassat, 2005), the mechanics of argillaceous media (Gajo and Loret, 2007), aquitard pore water chemistry (Tournassat et al., 2008), and groundwater (Timms and Hendry, 2007; McNab et al., 2009) and contaminant hydrology (Chatterjee et al., 2008; van Oploo et al., 2008; Serrano et al., 2009).

  17. Analytical applications of ion exchangers

    CERN Document Server

    Inczédy, J

    1966-01-01

    Analytical Applications of Ion Exchangers presents the laboratory use of ion-exchange resins. This book discusses the development in the analytical application of ion exchangers. Organized into 10 chapters, this book begins with an overview of the history and significance of ion exchangers for technical purposes. This text then describes the properties of ion exchangers, which are large molecular water-insoluble polyelectrolytes having a cross-linked structure that contains ionic groups. Other chapters consider the theories concerning the operation of ion-exchange resins and investigate th

  18. Effect of Rare Earth Elements on Exchange Performances of Cesium Ion-Sieve

    Institute of Scientific and Technical Information of China (English)

    张惠源; 王榕树; 林灿生; 张先业

    2003-01-01

    The exchange performances and the distribution coefficient of Cesium Ion-Sieve (Cs-IS) for cesium and for some rare earth elements were compared. In particular, the effects of neodymium on the cesium ion exchange and the Cs+ selectivity variation on Cs-IS owing to introduction of rare earth elements into HLLW were studied. Though rare earth elements exhibit a small influence on the distribution coefficient for Cs+, they impair Cs-exchange capacity of Cs-IS to some extent. This interruption on the selectivity to Cs+ can be significantly eliminated provided an appropriate ratio of liquid to solid V:m is used.

  19. A study on dry decontamination using ion exchange polymer

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ki Jung; Ahn, Byung Gil

    1997-12-01

    Through the project of {sup A} study on dry decontamination using ion exchange polymer{sup ,} the followings were investigated. 1. Highly probable decontamination technologies for the decontamination were investigated. 2. Development of gel type decontamination agent using ion-exchange resin powder (mixed type) as an ion exchanger. 3. Manufacturing of contaminated specimens (5 kinds) with Cs-137 solution and dust / Cs-137 solution. 4. Decontamination performance evaluation of the manufactured agent. 5. Analysis of composition (XRF) and the structure of surface of specimens (optic micrography). (author). 20 refs., 11 figs.

  20. Macroreticular chelating ion-exchangers.

    Science.gov (United States)

    Hirsch, R F; E Gancher, R; Russo, F R

    1970-06-01

    Two macroreticular chelating ion-exchangers have been prepared and characterized. One contains the iminodiacetate group and the second contains the arsonate group as the ion-exchanging site. The macroreticular resins show selectivities among metal ions similar to those of the commercially available naicroreticular chelating resins. Chromatographie separations on the new resins are rapid and sharp.

  1. Inorganic ion exchangers for nuclear waste remediation

    Energy Technology Data Exchange (ETDEWEB)

    Clearfield, A.; Bortun, A.; Bortun, L.; Behrens, E. [Texas A& M Univ., College Station, TX (United States)

    1997-10-01

    The objective of this work is to provide a broad spectrum of inorganic ion exchangers that can be used for a range of applications and separations involving remediation of groundwater and tank wastes. The authors intend to scale-up the most promising exchangers, through partnership with AlliedSignal Inc., to provide samples for testing at various DOE sites. While much of the focus is on exchangers for removal of Cs{sup +} and Sr{sup 2+} from highly alkaline tank wastes, especially at Hanford, the authors have also synthesized exchangers for acid wastes, alkaline wastes, groundwater, and mercury, cobalt, and chromium removal. These exchangers are now available for use at DOE sites. Many of the ion exchangers described here are new, and others are improved versions of previously known exchangers. They are generally one of three types: (1) layered compounds, (2) framework or tunnel compounds, and (3) amorphous exchangers in which a gel exchanger is used to bind a fine powder into a bead for column use. Most of these exchangers can be regenerated and used again.

  2. Sorption study and contribution of ion exchange in the dynamics of {sup 137}Cs n highly weathered soils; Estudo da sorcao e da contribuicao da troca ionica na dinamica do {sup 137}Cs em solos altamente intemperizados

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento Sobrinho, Guilherme Augusto

    2014-08-01

    The present study investigated the sorption kinetics and the reversibility of {sup 137}Cs within highly weathered soils, by means of sorption isotherms and desorption with three concentrations of silver thiourea (AgTU). For this purpose, four soils were selected based on their mineralogy and pedogenetics and sampled from lysimeters placed within the experimental area of the Tropical Radioecology Laboratory of the Institute for Radioprotection and Dosimetry. Three of them were tropical soils, belonging to the Argissolo (ARG), Latossolo vermelho (LV) and Latossolo vermelho amarelo (LVA) classes, and one subtropical, belonging to the Nitossolo (NIT) class. The 'goodness-of-fit' of the constant partition, Langmuir and Freundlich isotherms to the experimental data were assessed by means of a 'traditional' approach, i.e. correlation (R) and determination (R{sup 2}) coefficients, and a 'theoretic-informative' one, based upon the Corrected Akaike Information Criteria (AICc). In this work became clear that even presenting high affinity for the soil surface, once the sorption equilibrium was reached within 24 h (66 to 97% of sorbed {sup 137}Cs), quite a lot of this radionuclide remains easily mobile (40 to 73% of desorbed {sup 137}Cs), by means of a single extraction with AgTU 0,05 mol.L-1, and that such reversibility relates in an inverse manner to the sorption capacity of the studied soils for {sup 137}Cs. This work pointed also that the constant partition model, mostly known as Kdi, does not fit at all for the sorption data gathered for four highly weathered soils from four mineralogical groups, and for a very dilute solution of {sup 137}Cs. The mathematical model that most adequately described the sorption data for the four studied soils was the Langmuir equation (R{sup 2} > 0,95). The multi model analysis was not able to support generalizations for the four soils. The three models considered in this study provided good predictions of the

  3. Waste separation and pretreatment using crystalline silicotitanate ion exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Tadros, M.E.; Miller, J.E. [Sandia National Lab., Albuquerque, NM (United States); Anthony, R.G. [Texas A& M Univ., College Station, TX (United States)

    1997-10-01

    A new class of inorganic ion exchangers called crystalline silicotitanates (CSTs) has been developed jointly by Sandia National Laboratories and Texas A&M University to selectively remove Cs and other radionuclides from a wide spectrum of radioactive defense wastes. The CST exhibits high selectivity and affinity for Cs and Sr under a wide range of conditions. Tests show it can remove part-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. The materials exhibit ion exchange properties based on ionic size selectivity. Specifically, crystalline lattice spacing is controlled to be highly selective for Cs ions even in waste streams containing very high (5 to 10 M) concentrations of sodium. The CST technology is being demonstrated with actual waste at several DOE facilities. The use of inorganic ion exchangers. The inorganics are more resistant to chemical, thermal, and radiation degradation. Their high selectivities result in more efficient operations offering the possibility of a simple single-pass operation. In contrast, regenerable organic ion exchangers require additional processing equipment to handle the regeneration liquids and the eluant with the dissolved Cs.

  4. Electrically Switched Cesium Ion Exchange

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Fundamental studies on the Cs dynamics under ion source conditions

    Energy Technology Data Exchange (ETDEWEB)

    Friedl, R., E-mail: roland.friedl@physik.uni-augsburg.de; Fantz, U. [AG Experimentelle Plasmaphysik (EPP), Institute of Physics, University of Augsburg, 86135 Augsburg (Germany); Max-Planck-Institut für Plasmaphysik, EURATOM Association, Boltzmannstraße 2, 85748 Garching (Germany)

    2014-02-15

    The performance of surface conversion based negative hydrogen ion sources is mainly determined by the caesium dynamics. Therefore, fundamental investigations in vacuum and plasma are performed at a flexible laboratory setup with ion source parameters. Studies on the influence of Cs on the plasma parameters of H{sub 2} and D{sub 2} plasmas showed that n{sub e} and T{sub e} in the bulk plasma are not affected by relevant amounts of Cs and no isotopic differences could be observed. The coating of the vessel surfaces with Cs, however, leads to a considerable gettering of hydrogen atoms from the plasma volume and to the decrease of n{sub e} close to a sample surface due to the formation of negative ions.

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

    Directory of Open Access Journals (Sweden)

    Omerašević Mia

    2016-01-01

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

  7. Laser Decontamination of Surfaces Contaminated with Cs+ Ion

    Energy Technology Data Exchange (ETDEWEB)

    Baigalmaaa, B.; Won, H. J.; Moon, J. K.; Jung, C. H.; Lee, K. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Hyun, J. H. [Chungnam National University, Daejon (Korea, Republic of)

    2008-10-15

    Laser decontamination technology has been proven to be an efficient method for a surface modification of metals and concretes contaminated with radioactive isotopes. Furthermore, the generation of a secondary waste is negligible. The radioactivity of hot cells in the DFDF (Dupic Fuel Development Facility) is presumed to be very high and the predominant radionuclide is Cs-137. A series of laser decontamination studies by a fabricated Q-switched Nd:YAG laser system were performed on stainless steel specimens artificially contaminated with Cs+ ion. Decontamination characteristics of the stainless steel were analyzed by SEM and EPMA.

  8. Pharmaceutical Applications of Ion-Exchange Resins

    Science.gov (United States)

    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…

  9. Ion-exchange chromatographic protein refolding

    NARCIS (Netherlands)

    Freydell, E.; Wielen, van der L.; Eppink, M.H.M.; Ottens, M.

    2010-01-01

    The application of ion-exchange (IEX) chromatography to protein refolding (IExR) has been successfully proven, as supported by various studies using different model proteins, ion-exchange media and flow configurations. Ion-exchange refolding offers a relatively high degree of process

  10. Ion-exchange chromatographic protein refolding

    NARCIS (Netherlands)

    Freydell, E.; Wielen, van der L.; Eppink, M.H.M.; Ottens, M.

    2010-01-01

    The application of ion-exchange (IEX) chromatography to protein refolding (IExR) has been successfully proven, as supported by various studies using different model proteins, ion-exchange media and flow configurations. Ion-exchange refolding offers a relatively high degree of process intensification

  11. Electrically controlled cesium ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, M. [Pacific Northwest Lab., Richland, WA (United States)

    1996-10-01

    Several sites within the DOE complex (Savannah River, Idaho, Oak Ridge and Hanford) have underground storage tanks containing high-level waste resulting from nuclear engineering activities. To facilitate final disposal of the tank waste, it is advantageous to separate and concentrate the radionuclides for final immobilization in a vitrified glass matrix. This task proposes a new approach for radionuclide separation by combining ion exchange (IX) and electrochemistry to provide a selective and economic separation method.

  12. Multicomponent liquid ion exchange with chabazite zeolites

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-10-01

    In spite of the increasing commercial use of zeolites for binary and multicomponent sorption, the understanding of the basic mass-transfer processes associated with multicomponent zeolite ion-exchange systems is quite limited. This study was undertaken to evaluate Na-Ca-Mg-Cs-Sr ion exchange from an aqueous solution using a chabazite zeolite. Mass-transfer coefficients and equilibrium equations were determined from experimental batch-reactor data for single and multicomponent systems. The Langmuir isotherm was used to represent the equilibrium relationship for binary systems, and a modified Dubinin-Polyani model was used for the multicomponent systems. The experimental data indicate that diffusion through the microporous zeolite crystals is the primary diffusional resistance. Macropore diffusion also significantly contributes to the mass-transfer resistance. Various mass-transfer models were compared to the experimental data to determine mass-transfer coefficients. Effective diffusivities were obtained which accurately predicted experimental data using a variety of models. Only the model which accounts for micropore and macropore diffusion occurring in series accurately predicted multicomponent data using single-component diffusivities. Liquid and surface diffusion both contribute to macropore diffusion. Surface and micropore diffusivities were determined to be concentration dependent.

  13. Ion exchange in KTiOPO4 crystals irradiated by copper and hydrogen ions.

    Science.gov (United States)

    Zhang, Ruifeng; Lu, Fei; Lian, Jie; Liu, Hanping; Liu, Xiangzhi; Lu, Qingming; Ma, Hongji

    2008-05-12

    Cs(+)-K+ ion exchanges were produced on KTiOPO4 crystals which is prior irradiated by Cu+ can H+ ions. The energy and dose of implanted Cu+ ions are 1.5 MeV and 0.5 x 10(14) ions/cm2, and that of H+ are 300 keV and 1 x 10(16) ions/cm2, respectively. The temperature of ions exchange is 430 degrees C, and the time range from 15 minutes to 30 minutes. The prism coupling method is used to measure the dark mode spectra of the samples. Compared with results of ion exchange on the sample without irradiations, both the number of guided mode and its corresponding effective refractive index are decreased. The experimental results indicate that the ion exchange rate closely related with the lattice damage and the damage layers formed in the depth of maximum nuclear energy deposition act as a barrier to block the ions diffuse into the sample and the concentration of defects can modify the speed of ion exchange..

  14. A Multi-Sample Cs-Sputter Negative Ion Source

    Energy Technology Data Exchange (ETDEWEB)

    Alton, G.D.; Ball, J.A.; Bao, Y.; Cui, B.; Reed, C.A.; Williams, C.

    1998-10-05

    A multi-sample Cs sputter negative-ion source, equipped with a conical-geometry, W-surface-ionizer has been designed and fabricated that permits sample changes without disruption of on-line accelerator operation. Sample changing is effected by actuating an electro-pneumatic control system located at ground potential that drives an air-motor-driven sample-indexing-system mounted at high voltage; this arrangement avoids complications associated with indexing mechanisms that rely on electronic power-supplies located at high potential. In-beam targets are identified by LED indicator lights derived from a fiber-optic, Gray-code target-position sensor. Aspects of the overall source design and details of the indexing mechanism along with operational parameters, ion optics. intensities, and typical emittances for a variety of negative-ion species will be presented in this report.

  15. Using Ion Exchange Chromatography to Separate and Quantify Complex Ions

    Science.gov (United States)

    Johnson, Brian J.

    2014-01-01

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

  16. Using Ion Exchange Chromatography to Separate and Quantify Complex Ions

    Science.gov (United States)

    Johnson, Brian J.

    2014-01-01

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

  17. Ion Exchange Formation via Sulfonated Bicomponent Nonwovens

    Science.gov (United States)

    Stoughton, Hannah L.

    For many years ion exchange resins were used to: remove heavy metals from water, recover materials from wastewater, and eliminate harmful gases from the air. While use of these resin beads dominates the ion exchange industry, the beads have limitations that should be considered when decisions are made to employ them. For instance, officials must balance the inherent zero sum surface area and porosity of the materials. This series of studies investigates the use of bicomponent nonwovens as a base substrate for producing high surface area ion exchange materials for the removal of heavy metal ions. Functionalized materials were produced in a two-step process: (1) PET/PE spunbond bicomponent fibers were fractured completely, producing the high surface area nonwoven to be used as the base ion exchange material, and (2) the conditions for functionalizing the PET fibers of the nonwoven webs were investigated where an epoxy containing monomer was grafted to the surface followed by sulfonation of the monomer. The functionalization reactions of the PET fibers were monitored based on: weight gain, FTIR, TOF-SIMS, and SEM. Ion exchange properties were evaluated using titration and copper ion removal capacity from test solutions. The relationship between web structure and removal efficiency of the metal ions was defined through a comparison of the bicomponent and homocomponent nonwovens for copper ion removal efficiency. The investigation revealed that utilizing the high surface area, fractured bicomponent nonwoven ion exchange materials with capacities comparable to commercially available ion exchange resins could be produced.

  18. Ion exchange performance of commercial crystalline silicotitanates for cesium removal

    Energy Technology Data Exchange (ETDEWEB)

    Braun, R.; Dangieri, T.J.; Fennelly, D.J. [and others

    1996-03-01

    A new class of inorganic ion exchangers called crystalline silicotitanates (CST), invented by researchers at Sandia National Laboratories and Texas A&M University, has been commercialized in a joint Sandia-UOP effort. The original developmental materials exhibited high selectivity for the ion exchange of cesium, strontium, and several other radionuclides from highly alkaline solutions containing molar concentrations of Na{sup +}. The materials also showed excellent chemical and radiation stability. Together, the high selectivity and stability of the CSTs made them excellent candidates for treatment of solutions such as the Hanford tank supernates and other DOE radwastes. Sandia National Laboratories and UOP have teamed under a Cooperative Research and Development Agreement (CRADA) to develop CSTs in the powdered form and in an engineered form suitable for column ion exchange use. A continuous-flow, column ion exchange process is expected to be used to remove Cs and other radionuclides from the Hanford supernatant. The powder material invented by the Sandia and Texas A&M team consists of submicron-size particles. It is not designed for column ion exchange but may be used in other applications.

  19. [Ion specificity during ion exchange equilibrium in natural clinoptilolite].

    Science.gov (United States)

    He, Yun-Hua; Li, Hang; Liu, Xin-Min; Xiong, Hai-Ling

    2015-03-01

    Zeolites have been widely applied in soil improvement and environment protection. The study on ion specificity during ion exchange equilibrium is of important significance for better use of zeolites. The maximum adsorption capacities of alkali ions during ion exchange equilibrium in the clinoptilolite showed obvious specificity. For alkali metal ions with equivalent valence, the differences in adsorption capacity increased with the decrease of ionic concentration. These results cannot be well explained by the classical theories including coulomb force, ionic size, hydration, dispersion force, classic induction force and surface complexation. We found that the coupling of polarization effects resulted from the quantum fluctuation of diverse alkali metal ions and electric field near the zeolite surface should be the primary reason for specific ion effect during ion exchange in zeolite. The result of this coupling effect was that the difference in the ion dipole moment increased with the increase of surface potential, which further expanded the difference in the adsorption ability between zeolite surface and ions, resulting in different ion exchange adsorption ability at the solid/liquid interface. Due to the high surface charge density of zeolite, ionic size also played an important role in the distribution of ions in the double diffuse layer, which led to an interesting result that distinct differences in exchange adsorption ability of various alkali metal ions were only detected at high surface potential (the absolute value was greater than 0.2 V), which was different from the ion exchange equilibrium result on the surface with low charge density.

  20. Evaluation of Alternate Ion Exchange Designs for CST Non-Elutable Ion Exchange Process

    Energy Technology Data Exchange (ETDEWEB)

    Yen, S.N.; Pike, J.A.; Jacobs, R.A.; Poirier, M.R.; Sahawneh, B.M.; Leugemors, R.K.

    2001-06-27

    A study of alternative column designs was initiated in late 2000 to explore ion exchange column design concepts outside of the baseline case. The study, which is discussed in detail in the report, has identified two promising commercially proven ion-exchange column designs as candidates to be developed further for application to CST ion-exchange technology.

  1. Ion exchange in the nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    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

    Energy Technology Data Exchange (ETDEWEB)

    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. Spin-Exchange-Relaxation-Free Magnetometry with Cs Vapor

    Science.gov (United States)

    2008-03-13

    Larmor precession 6,7. In Ref. 5, sensitivity of 5 pG /Hz was achieved with the cell operating at 190 °C using potassium atoms. Estimates of the...cell containing a droplet of Cs metal, 600 Torr He buffer gas to reduce the rate at which atoms in the central part of the cell diffuse to the cell...broadening of Cs lines by helium 19, we extrapolate the FWHM of the D1 and D2 optical resonances to be =15.7 and 14.1 GHz, respectively. The cell was

  4. Positively and Negatively Charged Cesium and (C60) m Cs n Cluster Ions.

    Science.gov (United States)

    Renzler, Michael; Kranabetter, Lorenz; Goulart, Marcelo; Scheier, Paul; Echt, Olof

    2017-05-25

    We report on the formation and ionization of cesium and C60Cs clusters in superfluid helium nanodroplets. Size distributions of positively and negatively charged (C60) m Cs n(±) ions have been measured for m ≤ 7, n ≤ 12. Reproducible intensity anomalies are observed in high-resolution mass spectra. For both charge states, (C60) m Cs3(±) and (C60) m Cs5(±) are particularly abundant, with little dependence on the value of m. Distributions of bare cesium cluster ions also indicate enhanced stability of Cs3(±) and Cs5(±), in agreement with theoretical predictions. These findings contrast with earlier reports on highly Cs-doped cationic fullerene aggregates which showed enhanced stability of C60Cs6 building blocks attributed to charge transfer. The dependence of the (C60) m Cs3(-) anion yield on electron energy shows a resonance that, surprisingly, oscillates in strength as m increases from 1 to 6.

  5. Organic Ion Exchangers. Synthesis, Characterization and Applications

    Institute of Scientific and Technical Information of China (English)

    E. S. Dragan

    2005-01-01

    @@ 1Introduction Organic ion exchangers in beads form are the most widely utilized materials in the purification, concentration and separation processes of inorganic and organic ions in many fields of science and industry[1,2]. Some original contributions in the preparation and characterization of porous organic ion exchangers will be summarized first. The main types of synthetic ion exchangers were obtained by polymer-analogous reactions performed on porous styrene-divinylbenzene copolymers (S-DVB)[3,4] and porous acrylonitrile-DVB copolymers (AN-DVB) [5,6]. Porous S-DVB copolymers were used as substrate for the synthesis of weak and strong base anion exchangers by chloromethylation reaction followed by the reaction with secondary or tertiary amines.Different chloromethylation agents were employed. Weak base anion exchangers with tertiary or primary amine groups were prepared starting from AN-DVB copolymers by aminolyse-hydrolyse reaction with asymmetrical diamines or ethylenediamine (EDA), respectively. Strong base anion exchangers were obtained by quaternization reaction with alkyl halides of the tertiary amine groups. Chelating ion exchangers with iminodiacetic groups were prepared by the carboxymethylation reaction of the primary amine groups above mentioned and of those contained in a vinylamine-ethylacrylate-DVB copolymer, vinylamine units being generated by a Hofmann degradation reaction of the primary amide groups contained in the acrylamide-ethylacrylate-DVB copolymerp[7]. An amphoteric ion exchanger was prepared by the hydrolysis of the ester groups after the Hofmann degradation.

  6. First experiments with Cs doped Mo as surface converter for negative hydrogen ion sources

    Science.gov (United States)

    Schiesko, L.; Cartry, G.; Hopf, C.; Höschen, T.; Meisl, G.; Encke, O.; Heinemann, B.; Achkasov, K.; Amsalem, P.; Fantz, U.

    2015-08-01

    A study was conducted on the properties of molybdenum implanted with caesium as an approach to reduce the Cs consumption of negative hydrogen ion sources based on evaporated Cs. The depth profiles of the implanted Cs were simulated by SDTrimSP and experimentally determined by X-ray photoelectron spectroscopy depth profiling. In particular, one year after implantation, the depth profiles showed no signs of Cs diffusion into the molybdenum, suggesting long term stability of the implanted Cs atoms. The H- surface generation mechanisms on the implanted samples in hydrogen plasma were investigated, and the stability of the H- yield during four hours low power hydrogen plasma discharges was demonstrated. An estimation of the work function reduction (-0.8 eV) by the Cs implantation was performed, and a comparison of the relative negative ion yields between the implanted samples and highly oriented pyrolitic graphite showed that the Cs doped Mo negative ion yield was larger.

  7. ION EXCHANGE IN GLASS-CERAMICS

    Directory of Open Access Journals (Sweden)

    George Halsey Beall

    2016-08-01

    Full Text Available In the past few years ion-exchange in glasses has found a renewed interest with a lot of new development and research in industrial and academic labs and the commercialization of materials with outstanding mechanical properties. These glasses are now widely used in many electronic devices including hand-held displays and tablets. The exchange is generally conducted in a bath of molten salt below the transition temperature of the glass. The exchange at the surface of an alkali ion by a bigger one brings compressive stress at the surface. The mechanical properties are dependent on the stress level at the surface and the depth of penetration of the bigger ion. As compared to glasses, glass-ceramics have the interest to display a wide range of aspects (transparent to opaque and different mechanical properties (especially higher modulus and toughness. There has been little research on ion-exchange in glass-ceramics. In these materials the mechanisms are much more complex than in glasses because of their polyphasic nature: ion-exchange generally takes place mostly in one phase (crystalline phase or residual glass. The mechanism can be similar to what is observed in glasses with the replacement of an ion by another in the structure. But in some cases this ion-exchange leads to microstructural modifications (for example amorphisation or phase change.This article reviews these ion-exchange mechanisms using several transparent and opaque alumino-silicate glass-ceramics as examples. The effect of the ion exchange in the various glass-ceramics will be described, with particular emphasis on flexural strength.

  8. Ion Exchange in Glass-Ceramics

    Science.gov (United States)

    Beall, George; Comte, Monique; Deneka, Matthew; Marques, Paulo; Pradeau, Philippe; Smith, Charlene

    2016-08-01

    In the past few years ion-exchange in glasses has found a renewed interest with a lot of new development and research in industrial and academic labs and the commercialization of materials with outstanding mechanical properties. These glasses are now widely used in many electronic devices including hand-held displays and tablets. The exchange is generally conducted in a bath of molten salt below the transition temperature of the glass. The exchange at the surface of an alkali ion by a bigger one brings compressive stress at the surface. The mechanical properties are dependent on the stress level at the surface and the depth of penetration of the bigger ion. As compared to glasses, glass-ceramics have the interest to display a wide range of aspects (transparent to opaque) and different mechanical properties (especially higher modulus and toughness). There has been little research on ion-exchange in glass-ceramics. In these materials the mechanisms are much more complex than in glasses because of their polyphasic nature: ion-exchange generally takes place mostly in one phase (crystalline phase or residual glass). The mechanism can be similar to what is observed in glasses with the replacement of an ion by another in the structure. But in some cases this ion-exchange leads to microstructural modifications (for example amorphisation or phase change). This article reviews these ion-exchange mechanisms using several transparent and opaque alumino-silicate glass-ceramics as examples. The effect of the ion exchange in the various glass-ceramics will be described, with particular emphasis on flexural strength.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  11. Advanced integrated solvent extraction and ion exchange systems

    Energy Technology Data Exchange (ETDEWEB)

    Horwitz, P. [Argonne National Lab., IL (United States)

    1996-10-01

    Advanced integrated solvent extraction (SX) and ion exchange (IX) systems are a series of novel SX and IX processes that extract and recover uranium and transuranics (TRUs) (neptunium, plutonium, americium) and fission products {sup 90}Sr, {sup 99}Tc, and {sup 137}Cs from acidic high-level liquid waste and that sorb and recover {sup 90}Sr, {sup 99}Tc, and {sup 137}Cs from alkaline supernatant high-level waste. Each system is based on the use of new selective liquid extractants or chromatographic materials. The purpose of the integrated SX and IX processes is to minimize the quantity of waste that must be vitrified and buried in a deep geologic repository by producing raffinates (from SX) and effluent streams (from IX) that will meet the specifications of Class A low-level waste.

  12. Design of Ion-Exchange Resins Through EDTA and DTPA Modified Ligands

    Directory of Open Access Journals (Sweden)

    2014-07-01

    Catechol, resorcinol, and their admixtures with EDTA and DTPA moieties were converted into polymeric resins by alkaline polycondensation with formaldehyde. The resins were characterized by FTIR spectroscopy, elemental analysis, ion-exchange capacity, and distribution coefficient (D for heavy metal and radionuclide such as Cs and Sr. 137Cs and 90Sr constitutes a major source of heat in nuclear waste streams and in regards to recent nuclear event their remediation in complex solution – sea water - represent an important issue.

  13. Cation immobilization in pyrolyzed simulated spent ion exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Luca, Vittorio, E-mail: vluca@cnea.gov.ar [Programa Nacional de Gestion de Residuos Radiactivos, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina); Bianchi, Hugo L. [Gerencia de Quimica, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Av. General, Paz 1499, 1650 San Martin, Provincia de Buenos Aires (Argentina); ECyT, Universidad Nacional de General San Martin, Campus Miguelete, Ed. Tornavias, Martin de Irigoyen 3100, 1650 San Martin (Argentina); Conicet, Av. Rivadavia 1917, 1033 Buenos Aires (Argentina); Manzini, Alberto C. [Programa Nacional de Gestion de Residuos Radiactivos, Comision Nacional de Energia Atomica, Av. Del Libertador 8250, CP 1429, Ciudad Autonoma de Buenos Aires (Argentina)

    2012-05-15

    Significant quantities of spent ion exchange resins that are contaminated by an assortment of radioactive elements are produced by the nuclear industry each year. The baseline technology for the conditioning of these spent resins is encapsulation in ordinary Portland cement which has various shortcomings none the least of which is the relatively low loading of resin in the cement and the poor immobilization of highly mobile elements such as cesium. The present study was conducted with cationic resin samples (Lewatit S100) loaded with Cs{sup +}, Sr{sup 2+}, Co{sup 2+}, Ni{sup 2+} in roughly equimolar proportions at levels at or below 30% of the total cation exchange capacity. Low temperature thermal treatment of the resins was conducted in inert (Ar), or reducing (CH{sub 4}) gas atmospheres, or supercritical ethanol to convert the hydrated polymeric resin beads into carbonaceous materials that contained no water. This pyrolytic treatment resulted in at least a 50% volume reduction to give mechanically robust spherical materials. Scanning electron microscope investigations of cross-sections of the beads combined with energy dispersive analysis showed that initially all elements were uniformly distributed through the resin matrix but that at higher temperatures the distribution of Cs became inhomogeneous. Although Cs was found in the entire cross-section, a significant proportion of the Cs occurred within internal rings while a proportion migrated toward the outer surfaces to form a crustal deposit. Leaching experiments conducted in water at 25 Degree-Sign C showed that the divalent contaminant elements were very difficult to leach from the beads heated in inert atmospheres in the range 200-600 Degree-Sign C. Cumulative fractional loses of the order of 0.001 were observed for these divalent elements for temperatures below 500 Degree-Sign C. Regardless of the processing temperature, the cumulative fractional loss of Cs in water at 25 Degree-Sign C reached a plateau or

  14. Characterization of Cr ion exchange with hydrotalcite.

    Science.gov (United States)

    Terry, Patricia A

    2004-11-01

    Experiments were performed to characterize the removal of chromium from water with uncalcined hydrotalcite, a clay mineral ion exchange media. The process was characterized as a function of pH, temperature, contact time, and both Cr and hydrotalcite concentrations. A Freundlich isotherm, used to describe adsorption equilibria, was used as a model and Freundlich constants were determined. The kinetics of the ion exchange reaction were also modeled using a pseudo-first order reaction rate. Finally, an equilibrium stage process was modeled with sequential batch separations to determine if hydrotalcite ion exchange could reduce aqueous Cr levels to below the EPA limit of 0.1mgl(-1). It was shown that the process is highly pH dependent, only yielding significant removals at pH levels between 2.0 and 2.1. While hydrotalcite concentration, Cr concentration, and time did effect the ion exchange, temperature was not found to be a factor. Under optimal conditions, maximum removals of greater than 95% were achieved. Finally, sequential batch tests performed on initial Cr solutions ranging from 5mgl(-1) to 40mgl(-1), demonstrated that the water could be purified to a level that was not statistically different than the EPA limit, thus demonstrating the applicability of hydrotalcite ion exchange.

  15. Effect of polyamine reagents on exchange capacity in ion exchangers

    Science.gov (United States)

    Petrova, T. I.; Dyachenko, F. V.; Bogatyreva, Yu. V.; Borodastov, A. K.; Ershova, I. S.

    2016-05-01

    Effect of compounds involved in complex reagents is described using Helamin 906H reagent as an example. The working exchange capacity of KU-2-8chs cation exchanger in hydrogen form and Amberlite IRA 900Cl anion exchanger in OH form remained almost unchanged when they were used repeatedly to purify water that contained Helamin 906H reagent; in addition, this capacity was the same upon filtration of water that did not contain this reagent. Leakage of total organic carbon was observed earlier than that of calcium ions upon filtration of the solution through the cation exchanger layer. The test results obtained in industrial conditions indicated that using H-OH filters to purify turbine condensate enables the decrease of the concentration of organic and other impurities therein.

  16. Modeling of Crystalline Silicotitanate Ion Exchange Columns

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.D.

    1999-03-09

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

  17. Ion Exchange Testing with SRF Resin FY2012

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-06-11

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

  18. Crystal structures of a natural and a Cs-exchanged clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Smyth, J.R.; Spaid, A.T. [Univ. of Colorado, Boulder (USA); Bish, D.L. [Los Alamos National Laboratory, NM (USA)

    1990-05-01

    The crystal structures of natural and Cs-exchanged silica-rich clinoptilolite have been refined in space group C2/m using single-crystal X-ray diffraction data (R = 0.062 and 0.083, respectively; all reflections). Chemical formulae of the two structures are Na{sub 1.3}K{sub 1.2}Ca{sub 1.55}Al{sub 6.2}Si{sub 29.8}O{sub 72}{center_dot}23H{sub 2}O and Cs{sub 3.8}Ca{sub 1.2}Al{sub 6.1}Si{sub 29.7}O{sub 72}{center_dot}19H{sub 2}O. Unit-cell dimensions of the two are virtually identical (a = 17.633 {angstrom}, b = 17.941 {angstrom}, c = 7.400 {angstrom}, and {beta} = 116.39{degree} for the natural sample, and a = 17.692 {angstrom}, b = 17.945 {angstrom}, c = 7.404 {angstrom}, and {beta} = 116.36{degree} for the Cs-exchanged sample). The positions of extra-framework cations in the natural sample are similar to those reported previously, except that there is no atom at the position ascribed to Mg, consistent with the low Mg content of the sample. Cs occupies split positions near high-symmetry special positions that are unrelated to the cation positions in the natural sample. All Cs positions have relatively long Cs-H{sub 2}O and Cs-O distances ranging from 3.0 to 3.5 {angstrom}. Clinoptilolite is a major component in tuffs at the Nevada Test Site, a large reservation in southern Nevada used for underground testing of nuclear weapons, and it may be used for future isolation of high-level radioactive wastes.

  19. STATE OF WATER SORBED ON ION EXCHANGERS

    Institute of Scientific and Technical Information of China (English)

    VenkataramaniB

    1994-01-01

    Water sorption isotherms available in the literatures of Na+-from of Dowex 50W×4 and×8,BioRex-70,Amberlyst-15,Nafion-117,hydrous titanium oxide,crystalline zirconium phosphate and zinc hexacyanoferrate(Ⅱ),have been analysed by the D′Arcy and Watt equation.Hydration of Na+ in the ion exchangers is the predominant interaction of sorbed water.The correlation between the hydration numbers and those obtained for electrolyte solution is found in this paper.Qualitative implications of the state of sorbed water in the ion exchangers on its various characteristic quantities like selectivity,are briefly discussed.

  20. Ion exchange tempering of glass ophthalmic lenses.

    Science.gov (United States)

    Keeney, A H; Duerson, H L

    1975-08-01

    We performed low velocity drop-ball tests using 5/8-, 7/8-, and 1-inch diameter steel balls on ophthalmic crown glass lenses chemically tempered by the ion exchange process. Four representative dioptric strengths (+ 2.50 spherical, - 2.50 spherical, -2.50 cylindrical, and plano) were studied with the isolated lenses mounted, convex side up, on the American National Standards Institute Z80 test block. New ion exchange lenses exhibited a 100 to 350% greater capacity for attenuation of energy from low velocity, large size missiles than matched lenses of similar strength prepared by the conventional heat-treating and air-quenching process.

  1. Modeling ion exchange in clinoptilolite using the EQ3/6 geochemical modeling code

    Energy Technology Data Exchange (ETDEWEB)

    Viani, B.E.; Bruton, C.J.

    1992-06-01

    Assessing the suitability of Yucca Mtn., NV as a potential repository for high-level nuclear waste requires the means to simulate ion-exchange behavior of zeolites. Vanselow and Gapon convention cation-exchange models have been added to geochemical modeling codes EQ3NR/EQ6, allowing exchange to be modeled for up to three exchangers or a single exchanger with three independent sites. Solid-solution models that are numerically equivalent to the ion-exchange models were derived and also implemented in the code. The Gapon model is inconsistent with experimental adsorption isotherms of trace components in clinoptilolite. A one-site Vanselow model can describe adsorption of Cs or Sr on clinoptilolite, but a two-site Vanselow exchange model is necessary to describe K contents of natural clinoptilolites.

  2. Modeling ion exchange in clinoptilolite using the EQ3/6 geochemical modeling code

    Energy Technology Data Exchange (ETDEWEB)

    Viani, B.E.; Bruton, C.J. [Lawrence Livermore National Lab., CA (United States)

    1992-12-31

    Potential disposal of high-level nuclear waste at Yucca Mtn., Nevada requires the means to simulate ion-exchange behavior of clays and zeolites. Vanselow and Gapon convention cation-exchange models have been added to geochemical modeling codes EQ3NR/EQ6, allowing exchange to be modeled for up to three exchangers or a single exchanger with three independent sites. Solid-solution models that are numerically equivalent to the ion-exchange models were derived and also implemented in the code. The Gapon model is inconsistent with experimental adsorption isotherms of trace components in clinoptilolite. A one-site Vanselow model can describe adsorption of Cs and Sr on clinoptilolite, but a two-site Vanselow exchange model is necessary to describe K contents of natural clinoptilolites. 15 refs., 5 figs., 1 tab.

  3. CsI-Silicon Particle detector for Heavy ions Orbiting in Storage rings (CsISiPHOS)

    Science.gov (United States)

    Najafi, M. A.; Dillmann, I.; Bosch, F.; Faestermann, T.; Gao, B.; Gernhäuser, R.; Kozhuharov, C.; Litvinov, S. A.; Litvinov, Yu. A.; Maier, L.; Nolden, F.; Popp, U.; Sanjari, M. S.; Spillmann, U.; Steck, M.; Stöhlker, T.; Weick, H.

    2016-11-01

    A heavy-ion detector was developed for decay studies in the Experimental Storage Ring (ESR) at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. This detector serves as a prototype for the in-pocket particle detectors for future experiments with the Collector Ring (CR) at FAIR (Facility for Antiproton and Ion Research). The detector includes a stack of six silicon pad sensors, a double-sided silicon strip detector (DSSD), and a CsI(Tl) scintillation detector. It was used successfully in a recent experiment for the detection of the β+-decay of highly charged 142Pm60+ ions. Based on the ΔE / E technique for particle identification and an energy resolution of 0.9% for ΔE and 0.5% for E (Full Width at Half Maximum (FWHM)), the detector is well-suited to distinguish neighbouring isobars in the region of interest.

  4. The characteristic assessment of spent ion exchange resin from PUSPATI TRIGA REACTOR (RTP) for immobilization process

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Thermal Analysis of LANL Ion Exchange Column

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Radiation effects on ion exchange materials

    Energy Technology Data Exchange (ETDEWEB)

    Gangwer, T.E.; Goldstein, M.; Pillay, K.K.S.

    1977-11-01

    An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers are reviewed. Experimental parameters useful in characterizing the effects of radiation on synthetic ion exchange resins are identified or defined. In compiling the diverse types of data, an effort was made to present the experimental data or experimentally based parameters in a format that would be useful for inter-comparing radiation effects on resins. When subject to radiation there are various general trends or qualitative effects displayed by the different types of resins. These radiation-trends and effects have been formulated into qualitative statements. The present day level of understanding of the behavior of resins under ionizing radiation is too limited to justify quantitative predictive modeling. The limitations and deficiencies of the literature are discussed and the experimentation needed to achieve quantitative modeling are outlined. 14 figs., 108 references.

  7. Free volume and gas permeation in ion-exchanged forms of the Nafion® membrane

    Science.gov (United States)

    Mohamed, Hamdy F. M.; Kobayashi, Y.; Kuroda, C. S.; Ohira, A.

    2010-04-01

    Variations of free volume and gas permeability of the Nafion® membrane upon ion-exchange of H+ with Cs+ or Pt2+ was studied as a function of temperature. Free volume was quantified using the positron annihilation lifetime technique. Our results showed that the free volume (VFV,Ps) of the dried membrane is enlarged by thermal expansion. It was found that the ion-exchange significantly expands the free volume and at the same time decreases the permeabilities of O2 and H2. Good linear correlations between the logarithm of permeabilities of O2 and H2 at different temperatures and 1/VFV,Ps for the ion-exchanged forms of Nafion® in the dried state suggest an important role played by the free volume in gas permeation. Considerable downward deviation of the correlations for the ion-exchanged ionomers from the H+-form suggested the importance of polymer stiffening in gas permeation.

  8. SPEEDUP{trademark} ion exchange column model

    Energy Technology Data Exchange (ETDEWEB)

    Hang, T.

    2000-03-06

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

  9. An Empirical Formula From Ion Exchange Chromatography and Colorimetry.

    Science.gov (United States)

    Johnson, Steven D.

    1996-01-01

    Presents a detailed procedure for finding an empirical formula from ion exchange chromatography and colorimetry. Introduces students to more varied techniques including volumetric manipulation, titration, ion-exchange, preparation of a calibration curve, and the use of colorimetry. (JRH)

  10. First experiments with Cs doped Mo as surface converter for negative hydrogen ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Schiesko, L., E-mail: loic.schiesko@ipp.mpg.de; Hopf, C.; Höschen, T.; Meisl, G.; Encke, O.; Heinemann, B.; Fantz, U. [Max-Planck-Institut für Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany); Cartry, G.; Amsalem, P. [Aix Marseille University, CNRS, PIIM, UMR 7345, F-13013 Marseille (France); Achkasov, K. [Aix Marseille University, CNRS, PIIM, UMR 7345, F-13013 Marseille (France); CEA-Cadarache, IRFM, F-13108 St Paul lez Durance (France)

    2015-08-21

    A study was conducted on the properties of molybdenum implanted with caesium as an approach to reduce the Cs consumption of negative hydrogen ion sources based on evaporated Cs. The depth profiles of the implanted Cs were simulated by SDTrimSP and experimentally determined by X-ray photoelectron spectroscopy depth profiling. In particular, one year after implantation, the depth profiles showed no signs of Cs diffusion into the molybdenum, suggesting long term stability of the implanted Cs atoms. The H{sup −} surface generation mechanisms on the implanted samples in hydrogen plasma were investigated, and the stability of the H{sup −} yield during four hours low power hydrogen plasma discharges was demonstrated. An estimation of the work function reduction (−0.8 eV) by the Cs implantation was performed, and a comparison of the relative negative ion yields between the implanted samples and highly oriented pyrolitic graphite showed that the Cs doped Mo negative ion yield was larger.

  11. Microstructure and Cs Behavior of Ba-Doped Aluminosilicate Pollucite Irradiated with F+ Ions

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Weilin; Kovarik, Libor; Zhu, Zihua; Varga, Tamas; Engelhard, Mark H.; Bowden, Mark E.; Nenoff, Tina M.; Garino, Terry

    2014-06-24

    Radionuclide 137Cs is one of the major fission products that dominate heat generation in spent fuels over the first 300 hundred years. A durable waste form for 137Cs that decays to 137Ba is needed to minimize its environmental impact. Aluminosilicate pollucite CsAlSi2O6 is selected as a model waste form to study the decay-induced structural effects. While Ba-containing precipitates are not present in charge-balanced Cs0.9Ba0.05AlSi2O6, they are found in Cs0.9Ba0.1AlSi2O6 and identified as monoclinic Ba2Si3O8. Pollucite is susceptible to electron irradiation induced amorphization. The threshold density of the electronic energy deposition for amorphization is determined to be ~235 keV/nm3. Pollucite can be readily amorphized under F+ ion irradiation at 673 K. A significant amount of Cs diffusion and release from the amorphized pollucite is observed during the irradiation. However, cesium is immobile in the crystalline structure under He+ ion irradiation at room temperature. The critical temperature for amorphization is not higher than 873 K under F+ ion irradiation. If kept at or above 873 K all the time, the pollucite structure is unlikely to be amorphized; Cs diffusion and release are improbable. A general discussion regarding pollucite as a potential waste form is provided in this report.

  12. Porous solid ion exchange wafer for immobilizing biomolecules

    Science.gov (United States)

    Arora, Michelle B.; Hestekin, Jamie A.; Lin, YuPo J.; St. Martin, Edward J.; Snyder, Seth W.

    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.

  13. THE KINETICS OF FILM-DIFFUSION-LIMITED ION-EXCHANGE

    NARCIS (Netherlands)

    KRAAIJEVELD, G; WESSELINGH, JA

    1993-01-01

    The film-diffusion-limited ion exchange kinetics for the HCl-NaCl and HCl-CaCl2 systems on a Lewatit S100 ion exchanger are investigated. The ion exchange processes are modelled using the Maxwell-Stefan transport equations. The model uses only one fitting parameter. the film thickness, the Maxwell-S

  14. Solidification of Spent Ion Exchange Resin Using ASC Cement

    Institute of Scientific and Technical Information of China (English)

    周耀中; 云桂春; 叶裕才

    2002-01-01

    Ion exchange resins (IERs) have been widely used in nuclear facilities. However, the spent radioactive IERs result in major quantities of low and intermediate level radioactive wastes. This article describes a laboratory experimental study on solidification processing of IERs using a new type of cement named ASC cement. The strength of the cementation matrix is in the range of 18-20 MPa (28 d); the loading of the spent IER in the cement-resin matrix is over 45% and leaching rates of 137Cs, 90Sr and 60Co are 7.92×10-5, 5.7×10-6, and 1.19×10-8 cm/d. The results show that ASC cement can be a preferable cementation material for immobilization of radioactive spent IER.

  15. Cesium and strontium ion specific exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Yates, S.

    1996-10-01

    This work is one of two parallel projects that are part of an ESP task to develop high-capacity, selective, solid extractants for cesium, strontium, and technetium from nuclear wastes. In this subtask, Pacific Northwest National Laboratory (PNNL) is collaborating with AlliedSignal, Inc. (Des Plaines, Illinois) to develop inorganic ion exchangers that are selective for strontium and cesium from alkaline high-level waste and groundwater streams.

  16. PRTR ion exchange vault water removal

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. STUDIES ON SYNTHESIS AND CHARACTER OF INORGANIC ION EXCHANGER TITANIUM PHOSPHATE—AMMONIUM TUNGSTOPHOSPHATE

    Institute of Scientific and Technical Information of China (English)

    YuXintian; SunZhaoxiang

    1998-01-01

    In this paper,a new complex inorganic ion exchanger Titanium Phosphate-Ammonium Tungstophosphate(abbreviated as Tip-AWP) was synthesized,whose exchange character and chemical structure were studied.This compound exhibits high exchange capacity and selectivity for Cs+,its exchange capacity accains 0.95 mmol/g in the medium of 0.1mol/L HNO3,and which almost doesn′t change in the 1AW imitated waste solution.There are no change in exchange capacity and structute after several times of exchanging,eluting,regenerating,which is of great importance to the separation and uptaking of radio-nuclides.Further more,this exchanger has good thermal and redioactive stability.

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

    Science.gov (United States)

    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 μm 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.

  19. Collisions of alkali-metal atoms Cs and Rb in the ground state. Spin exchange cross sections

    Science.gov (United States)

    Kartoshkin, V. A.

    2016-09-01

    Collisions of alkali-metal atoms 133Cs and 85Rb in the ground state are considered in the energy interval of 10-4-10-2 au. Complex cross sections of the spin exchange, which allow one to calculate the processes of polarization transfer and the relaxation times, as well as the magnetic resonance frequency shifts caused by spin exchange Cs-Rb collisions, are obtained.

  20. Novel silica-based ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Gula, M.; Harvey, J.

    1996-12-31

    Shortcomings of chelating resins have been addressed by a new class of ion exchange resins called dual mechanism bifunctional polymers (DMBPs). DMBPs use hydrophilic cation exchange ligands with rapid uptake kinetics and use chelating ligands for selectivity for one or more metals; result is a resin that quickly recognizes and removes targeted metals from waste, remediation, and process streams. Eichrom`s Diphonix {reg_sign} resin is the first DMBP to be widely released as a commercial product; it is polystyrene based. Objective of this work is to synthesize commercial quantities of a silica-based ion exchange resin with the same or better metal ion selectivity, metal uptake kinetics, and acid stability as Diphonix. Feasibility was determined, however the process needs to be optimized. Studies at Eichrom and ANL of the performance of Diphonix resin over a broad range of HNO3 and HCl conditions and inorganic salt loadings are discussed together with the proposed method of incorporating similar characteristics into a silica-based resin. The new, silica-based resin functionalized with diphosphonic acid ligands can be used in environmental restoration and waste management situations involving processing of low-level, transuranic, and high-level radioactive wastes; it can also be used for processing liquid mixed waste including wastes contaminated with organic compounds.

  1. Optimum plasma grid bias for a negative hydrogen ion source operation with Cs

    Energy Technology Data Exchange (ETDEWEB)

    Bacal, Marthe, E-mail: marthe.bacal@lpp.polytechnique.fr [UPMC, LPP, Ecole Polytechnique, UMR CNRS 7648, Palaiseau (France); Sasao, Mamiko [R& D Promotion Organization, Doshisha University, Kamigyoku, Kyoto 602-8580 (Japan); Wada, Motoi [School of Science and Engineering, Doshisha University, Kyotonabe, Kyoto 610-0321 (Japan); McAdams, Roy [CCFE, Culham Science Center, Abingdon, Oxfordshire 0X14 3DB (United Kingdom)

    2016-02-15

    The functions of a biased plasma grid of a negative hydrogen (H{sup −}) ion source for both pure volume and Cs seeded operations are reexamined. Proper control of the plasma grid bias in pure volume sources yields: enhancement of the extracted negative ion current, reduction of the co-extracted electron current, flattening of the spatial distribution of plasma potential across the filter magnetic field, change in recycling from hydrogen atomic/molecular ions to atomic/molecular neutrals, and enhanced concentration of H{sup −} ions near the plasma grid. These functions are maintained in the sources seeded with Cs with additional direct emission of negative ions under positive ion and neutral hydrogen bombardment onto the plasma electrode.

  2. HEAT TRANSFER ANALYSIS FOR ION-EXCHANGE COLUMN SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.; King, W.

    2011-05-23

    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 (including Cs-137, Sr-90, and actinides) within a High Level Waste (HLW) storage tank at the Savannah River Site. The SCIX design includes CST columns inserted and supported in the tank top risers for cesium removal. Temperature distributions and maximum temperatures across the column were calculated with a focus on process upset conditions. A two-dimensional computational modeling approach for the in-column ion-exchange domain was taken to include conservative, bounding estimates for key parameters such that the results would provide the maximum centerline temperatures achievable under the design configurations using a feed composition known to promote high cesium loading on CST. The current full-scale design for the CST column includes one central cooling pipe and four outer cooling tubes. Most calculations assumed that the fluid within the column was stagnant (i.e. no buoyancy-induced flow) for a conservative estimate. A primary objective of these calculations was to estimate temperature distributions across packed CST beds immersed in waste supernate or filled with dry air under various accident scenarios. Accident scenarios evaluated included loss of salt solution flow through the bed, inadvertent column drainage, and loss of active cooling in the column. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature.

  3. Ion-exchange chromatographic protein refolding.

    Science.gov (United States)

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

    2010-11-12

    The application of ion-exchange (IEX) chromatography to protein refolding (IExR) has been successfully proven, as supported by various studies using different model proteins, ion-exchange media and flow configurations. Ion-exchange refolding offers a relatively high degree of process intensification, represented by the possibility of performing protein refolding, product purification and product concentration, in one unit operation. Besides its high degree of process intensification, IExR offers an additional set of key advantages including: spatial isolation of the bound protein molecules and the controllable change in chemical composition using gradients. Despite of the acknowledgement of the former advantages, the lack of mechanistic understanding on how they influence the process performance of the ion-exchange refolding reactor, limits the ability to exploit them in order to optimize the performance of the unit. This paper presents a quantitative analysis that assesses the effect that the spatial isolation and the urea gradient, have on the IExR performance, judged on the basis of the refolding yield (Y(N)) and the fractional mass recovery (f(Prot,Rec)). Additionally, this work discusses the effect of the protein load, the protein loading state (i.e., native, denatured, denatured and reduced (D&R)) and the adsorbent type on f(Prot,Rec). The presented work shows: (1) that the protein load has a direct effect on f(Prot,Rec), and the magnitude of this effect depends on the loading state of the protein solution and the adsorbent type; (2) that irrespectively of the type of adsorbent used, the saturation capacity of a denatured protein is less than the native protein and that this difference can be linked to differences in accessible binding surface area; (3) that there is a clear correlation between fractional surface coverage (θ) and f(Prot,Rec), indicating that the former could serve as a good descriptor to assess spatial isolation, and (4) that the urea

  4. Ion Exchange Testing with SRF Resin FY 2012

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-07-02

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

  5. Ion exchange properties of humus acids

    Science.gov (United States)

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

    2014-08-01

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

  6. Novel silica-based ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-11-01

    Eichrom`s highly successful Diphonixo resin resembles a conventional ion exchange resin in its use of sulfonic acid ligands on a styrene- divinylbenzene matrix. Diphonix resin exhibits rapid exchange kinetics that allow economical operation of ion exchange systems. Unlike conventional resins, Diphonix resin contains chelating ligands that are diphosphonic acid groups that recognize and remove the targeted metals and reject the more common elements such as sodium, calcium and magnesium. This latter property makes Diphonix ideal for many industrial scale applications, including those involving waste treatment. For treatment of low-level, transuranic (TRU) and high- level radioactive wastes, Diphonix`s polystyrene backbone hinders its application due to radiolytic stability of the carbon-hydrogen bonds and lack of compatibility with expected vitrification schemes. Polystyrene-based Diphonix is approximately 60% carbon- hydrogen. In response to an identified need within the Department of Energy for a resin with the positive attributes of Diphonix that also exhibits greater radiolytic stability and final waste form compatibility, Eichrom has successfully developed a new, silica-based resin version of Diphonix. Target application for this new resin is for use in environmental restoration and waste management situations involving the processing of low-level, transuranic and high-level radioactive wastes. The resin can also be used for processing liquid mixed waste (waste that contains low level radioactivity and hazardous constituents) including mixed wastes contaminated with organic compounds. Silica-based Diphonix is only 10% carbon-hydrogen, with the bulk of the matrix silica.

  7. Anion exchangers with branched functional ion exchange layers of different hydrophilicity for ion chromatography.

    Science.gov (United States)

    Shchukina, O I; Zatirakha, A V; Smolenkov, A D; Nesterenko, P N; Shpigun, O A

    2015-08-21

    Novel polystyrene-divinylbenzene (PS-DVB) based anion exchangers differing from each other in the structure of the branched functional ion exchange layer are prepared to investigate the role of linker and functional site on ion exchange selectivity. The proposed method of synthesis includes the obtaining of aminated PS-DVB particles by means of their acylation with following reductive amination with methylamine. Further modification of the obtained secondary aminogroups is provided by the alkylation with either 1,4-butanediol diglycidyl ether (1,4-BDDGE) or resorcinol diglycidyl ether (RDGE), which form the linkers of different hydrophobicity, and amination of terminal epoxide rings with trimethylamine (TMA), dimethylethanolamine (DMEA), methyldiethanolamine (MDEA) or triethanolamine (TEA). The variation of the structure and hydrophobicity of the linker and terminal quaternary ammonium sites in the functional layer allows the alteration of selectivity and separation efficiency of the obtained adsorbents. The ion exchange selectivity and separation efficiency of the anion exchangers are evaluated using the model mixtures of anions (F(-), HCOO(-), Cl(-), NO2(-), Br(-), NO3(-), HPO4(2-) and SO4(2-)) in potassium hydroxide eluents. The adsorbents show the decrease of selectivity with increasing the hydrophilicity of the terminal functional site. The anion exchangers having more flexible and hydrophilic 1,4-BDDGE linker provide smaller separation factors for most of the analytes as compared with RDGE-containing adsorbents with the same terminal ion exchange sites, but are characterized with higher column efficiencies and better peak symmetry for polarizable anions. In case of 1,4-BDDGE-modified anion exchangers of the particle size of 3.3μm functionalized with DMEA and MDEA the calculated values of column efficiencies for polarizable NO3(-) and Br(-) are up to 49,000 and 53,000N/m, respectively, which is almost twice higher than the values obtained for the RDGE

  8. Microbial treatment of ion exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Kouznetsov, A.; Kniazev, O. [D. Mendeleyev University of Chemical Technology of Russia, Dept. Biotechnology, Mocow (Russian Federation)

    2001-07-01

    A bioavailability of ion exchange resins to a microbial destruction as one of the alternative methods of compacting used ionites from the nuclear fuel manufacturing cycle enterprises has been investigated. The bio-destruction was studied after a preliminary chemical treatment or without it. A sensitivity of the ion exchange resins (including highly acidic cationite KU-2-8) to the microbial destruction by heterotrophic and chemo-litho-trophic microorganisms under aerobic conditions was shown in principle. The biodegradation of the original polymer is possible in the presence of the water soluble fraction of the resin obtained after its treatment by Fenton reagent and accelerated in the presence of Mn-ions in optimal concentration 1-2 g of Mn per liter of medium. Thus, the process of bio-destruction of ionite polymer by heterotrophic microorganisms can be compared with the bio-destruction of lignin or humic substances. The optimum parameters of bio-destruction and microorganisms used must be different for resins with different functional groups. (authors)

  9. DIFFUSIVITY OF ARRE EARTH ION IN POROUS ION EXCHANGE RESINS

    Institute of Scientific and Technical Information of China (English)

    LingDaren; LiuYucheng; 等

    1997-01-01

    The self-diffusion of Eu3+ ion in porous resins D72 and D751 was studied by isotope exchange reaction.Applying Kataoka's bidisperse pore model,the intraparticle effective diffusivity De were resolved into a solid diffusivity Dg and a macropore diffusivity Dp.The experiments show that De.Dp and Dg all increase with the increase of reaction temperature;the response Dp and Dg of D751 resin is smaller than that of D72 resin;the diffusivity of Eu3+ ion in solution is larger than Dp,which leads to the conclusion that the diffusion of ion in the pore of resin can not completely be equal to that in solution.

  10. Ion exchange materials, method of forming ion exchange materials, and methods of treating liquids

    Science.gov (United States)

    Wertsching, Alan K.; Peterson, Eric S.; Wey, John E.

    2007-12-25

    The invention includes an ion affinity material having an organic component which is sulfonated and which is chemically bonded to an inorganic substrate component. The invention includes a method of forming a metal binding material. A solid support material comprising surface oxide groups is provided and an organic component having at least one alkyl halide is covalently linked to at least some of the surface oxide groups to form a modified support material. The at least one alkyl halide is subsequently converted into an alkyl sulfonate. The invention further includes a method and system for extracting ions from a liquid. An ion exchange material having a sulfonated alkyl silane component covalently bonded to a metal oxide support material is provided and a liquid is exposed to the ion exchange material.

  11. The effect of Cs{sup +} ions on codeposition of SiC particles with nickel

    Energy Technology Data Exchange (ETDEWEB)

    Rudnik, Ewa, E-mail: erudnik@agh.edu.pl [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Department of Physical Chemistry and Metallurgy of Non-Ferrous Metals, Laboratory of Physical Chemistry and Electrochemistry, Al. Mickiewicza 30, 30-059 Cracow (Poland); Burzynska, Lidia; Gut, Marcin [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Department of Physical Chemistry and Metallurgy of Non-Ferrous Metals, Laboratory of Physical Chemistry and Electrochemistry, Al. Mickiewicza 30, 30-059 Cracow (Poland)

    2011-04-15

    Research highlights: {yields} The papers describes electrodeposition of SiC particles with nickel matrix in the presence of cesium ions. {yields} Correlations among the Cs{sup +} concentration in the bath, kinetics of the cathodic process, SiC content in the deposits as well as adsorption of Ni{sup 2+} ions on SiC were found. {yields} Microhardness of the Ni/SiC deposits was also determined. - Abstract: Electrodeposition of SiC particles (technical powder) with nickel matrix in the presence of cesium ions (0-37.6 mM) was investigated. The influence of Cs{sup +} concentration on cathodic polarization curves was determined in galvanostatic and potentiodynamic measurements. The presence of Cs{sup +} in the solution enhanced in some extent adsorption of Ni{sup 2+} ions on SiC, but preferential cesium adsorption occurred simultaneously. The last phenomenon resulted in cesium incorporation in the composite coating. The particle content in the deposits (16-24 vol%) was governed by the amount of nickel ions adsorbed on SiC. Structure of the composite coatings was studied by microscopic observations. At highest Cs{sup +} concentrations, incorporation of small SiC grains was inhibited. Microhardness of deposits (390-800 HV) was directly dependent on the SiC content in the coatings.

  12. Physicochemical characterization of the retardation of aqueous Cs+ ions by natural kaolinite and clinoptilolite minerals.

    Science.gov (United States)

    Shahwan, T; Akar, D; Eroğlu, A E

    2005-05-01

    The aim of this study was to carry out kinetic, thermodynamic, and surface characterization of the sorption of Cs+ ions on natural minerals of kaolinite and clinoptilolite. The results showed that sorption followed pseudo-second-order kinetics. The activation energies were 9.5 and 13.9 kJ/mol for Cs+ sorption on kaolinite and clinoptilolite, respectively. Experiments performed at four different initial concentrations of the ion revealed that the percentage sorption of Cs+ on clinoptilolite ranged from 90 to 95, compared to 28 to 40 for the kaolinite case. At the end of a 1 week period, the percentage of Cs+ desorption from clinoptilolite did not exceed 7%, while it amounted to more than 30% in kaolinite, indicating more stable fixation by clinoptilolite. The sorption data were best described using Freundlich and D-R isotherm models. Sorption showed spontaneous and exothermic behavior on both minerals, with deltaH(0) being -6.3 and -11.4 kJ/mol for Cs+ uptake by kaolinite and clinoptilolite, respectively. Expanding the kaolinite interlayer space from 0.71 to 1.12 nm using DMSO intercalation, did not yield a significant enhancement in the sorption capacity of kaolinite, indicating that the surface and edge sites of the clay are more energetically favored. EDS mapping and elemental analysis of the surface of kaolinite and clinoptilolite revealed more intense signals on the surface of the latter with an even distribution of sorbed Cs+ onto the surfaces of both minerals.

  13. Ion-exchange and hydrophobic interactions affecting selectivity for neutral and charged solutes on three structurally similar agglomerated ion-exchange and mixed-mode stationary phases.

    Science.gov (United States)

    Kazarian, Artaches A; Taylor, Mark R; Haddad, Paul R; Nesterenko, Pavel N; Paull, Brett

    2013-11-25

    The nature and extent of mixed-mode retention mechanisms evident for three structurally related, agglomerated, particle-based stationary phases were evaluated. These three agglomerated phases were Thermo Fisher ScientificIon PacAS11-HC - strong anion exchange, Thermo Fisher Scientific IonPac CS10--strong cation-exchange PS-DVB, and the Thermo Fisher Scientific Acclaim Trinity P1silica-based substrate, which is commercially marketed as a mixed-mode stationary phase. All studied phases can exhibit zwitterionic and hydrophobic properties, which contribute to the retention of charged organic analytes. A systematic approach was devised to investigate the relative ion-exchange capacities and hydrophobicities for each of the three phases, together with the effect of eluent pH upon selectivity, using a specifically selected range of anionic, cationic and neutral aromatic compounds. Investigation of the strong anion-exchange column and the Trinity P1 mixed-mode substrate, in relation to ion-exchange capacity and pH effects, demonstrated similar retention behaviour for both the anionic and ampholytic solutes, as expected from the structurally related phases. Further evaluation revealed that the ion-exchange selectivity of the mixed-mode phase exhibited properties similar to that of the strong anion-exchange column, with secondary cation-exchange selectivity, albeit with medium to high anion-exchange and cation-exchange capacities, allowing selective retention for each of the anionic, cationic and ampholytic solutes. Observed mixed-mode retention upon the examined phases was found to be a sum of anion- and cation-exchange interactions, secondary ion-exchange and hydrophobic interactions, with possible additional hydrogen bonding. Hydrophobic evaluation of the three phases revealed logP values of 0.38-0.48, suggesting low to medium hydrophobicity. These stationary phases were also benchmarked against traditional reversed-phase substrates namely, octadecylsilica YMC-Pac Pro C18

  14. Ion exchange pretreatment of alkaline radwaste for cesium removal

    Energy Technology Data Exchange (ETDEWEB)

    Bibler, J.P. [Westinghouse Savannah River Co., Aiken, SC (United States). Savannah River Technology Center

    1994-08-01

    A cation exchange resin has been tested for its ability to remove the Cs ion from simulants of highly alkaline liquid nuclear wastes found at the Savannah River Site, Oak Ridge, and Hanford. The resin is a condensation polymer of the K salt of resorcinol and formaldehyde. It removes milli- and micromolar amounts of Cs{sup +} from solutions that contain as high as 11 molar Na{sup +}. Small column tests indicate that approximately 200 column volumes of SRS simulant and 205 column volumes of OR Tank 25 supernatant simulant can be processed before the resin requires regeneration. For these two wastes, a carousel arrangement of two columns in series and a third in reserve can be used effectively in a process. Hanford 101-AW simulant generates a less sharp breakthrough profile with this resin, though an operation using a maximum of three columns in series with another column off-line for regeneration would be effective if the resin beds are allowed to reach about 90% breakthrough before taking them out of service. Parameters that effect the performance of the resin with a particular feed solution are the concentrations of the two primary ions of interest, Cs{sup +} and Na{sup +}, as well as the concentrations of K{sup +} and OH{sup {minus}}. A further ramification of the hydroxide ion concentration is its role in assisting oxidation of the resin, thereby destroying its usefulness in cesium removal. Although the performance of the resin is unaffected at doses of 1 E+8 rad ionizing radiation, it shows noticeable degradation after storage for 100 hours in alkaline solutions, generating quinone and ketone groups, as determined from C-13 NMR and by an increase in total organic C content of the contacting solution. Gases detected from the radiolysis of the resin/simulant mixture are CO{sub 2} from the resin, N{sub 2}O from nitrate in the simulant, and H{sub 2} possibly from resin and simulant. Oxygen depletion in the mixture results from radiolysis and chemical degradation.

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

    Science.gov (United States)

    Foster, N.; And Others

    1985-01-01

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

  16. Birefringence control for ion-exchanged channel glass waveguides.

    Science.gov (United States)

    Ayräs, P; Conti, G N; Honkanen, S; Peyghambarian, N

    1998-12-20

    We show that at 1.55-mum wavelength the waveguide birefringence of ion-exchanged channel waveguides in glass can be broadly tuned by a potassium and silver double-ion exchange. Two different potassium and silver double-ion-exchange processes are used to make surface waveguides with negligible waveguide birefringence. This process is crucially important in the manufacture of devices for dense wavelength-division multiplexing systems. The dependence of the waveguide birefringence on the channel width is also reported.

  17. Mineral Separation in a CELSS by Ion-exchange Chromatography

    Science.gov (United States)

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

    1982-01-01

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

  18. Zeolitic ammonium ion exchange for portable hemodialysis dialysate regeneration.

    Science.gov (United States)

    Patzer, J F; Yao, S J; Wolfson, S K

    1995-01-01

    Ammonia removal from a recirculating dialysate stream is a major challenge in developing a truly portable, regenerable hemodialysis system. Three zeolites, type F, type W, and clinoptilolite, were found to have good ammonia ion exchange capacity with linear equilibrium ion exchange coefficients of 0.908, 0.488, and 0.075 L/g, respectively. The linear equilibrium ion exchange coefficient relates dialysate ammonia concentration (mumol/L) to the amount of ammonia absorbed by zeolite (mumol/g) at equilibrium. Ammonia uptake by zeolite powders was fast, with equilibrium reached within 15 sec. Zeolite ammonia ion exchange and regeneration through multiple cycles was studied using an ion exchange column containing clinoptilolite pellets. Zeolite ion exchange capability was regenerated by flushing the column with 2 mol/L sodium chloride after an ion exchange run. The column maintained ammonia ion exchange capacity through six ion exchange/regeneration cycles, demonstrating multiple dialysis use possibilities. Atomic absorption spectroscopy of the column effluent showed no detectible (< 1 part per million) Si or Al leached from the zeolite.

  19. SYNTHESIS OF METHYL TERT-BUTYL ETHER CATALYZED BY ACIDIC ION-EXCHANGE RESINS - INFLUENCE OF THE PROTON ACTIVITY

    NARCIS (Netherlands)

    PANNEMAN, HJ; BEENACKERS, AACM

    1995-01-01

    The catalytic activity of various strong acid ion-exchange resins on the synthesis of methyl tert-butyl ether (MtBE) from methanol and isobutene has been investigated. Relative to Amberlyst 15, Kastel CS 381 and Amberlyst CSP have similar rate constants, whereas Duolite ES 276 and Amberlyst XE 307 h

  20. Decontamination Characteristics of Stainless Steel Surface Contaminated with Cs{sup +} Ion by Light Ablation

    Energy Technology Data Exchange (ETDEWEB)

    Baigalmaa, Byambatseren; Won, Hui-Jun; Moon, Jei-Kwon; Jung, Chong-Hun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Hyun, Jae-Hyuk [Chungnam National University, Daejeon (Korea, Republic of)

    2008-05-15

    The characteristics of decontamination method by light ablation are the remote operation, a short application time, and the high removal efficiency. Furthermore, the generation of the secondary waste is negligible. The radioactivity of hot cells in DFDF (Dupic Fuel Development Facility) is presumed to be very high and the predominant radionuclide is Cs-137. A series of laser decontamination studies by the fabricated Qswitched Nd-YAG laser system were performed on the stainless steel specimens artificially contaminated with Cs{sup +} ion. Decontamination characteristics of the stainless steel were analyzed by SEM and EPMA.

  1. Effects of ionizing radiation on modern ion exchange materials

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Scintillating 99Tc Selective Ion Exchange Resins

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell Greenhalgh; Richard D. Tillotson

    2012-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  4. Controlled porosity monolithic material as permselective ion exchange membranes.

    Science.gov (United States)

    Huang, Xiaojia; Dasgupta, Purnendu K

    2011-03-18

    Ion exchange membranes (IEMs) are used in a variety of analytical devices, including suppressors, eluent generators and other components used in ion chromatography. Such membranes are flexible and undergo substantial dimensional changes on hydration. Presently the push to miniaturization continues; a resurgent interest in open tubular ion chromatography requires microscale adaptation of these components. Incorporating IEMs in microscale devices is difficult. Although both macroporous and microporous ion exchange materials have been made for use as chromatographic packing, ion exchange material used as membranes are porous only on a molecular scale. Because such pores have vicinal ion exchange sites, ions of the same charge sign as those of the fixed sites are excluded from the IEMs. Monolithic polymers, including ion exchangers derived therefrom, are presently extensively used. When used in a separation column, such a monolithic structure contains an extensively connected porous network. We show here that by controlling the amount of porogen added during the synthesis of monolithic polymers derived from ethylene dimethacrylate - glycidyl methacrylate, which are converted to an anion exchanger by treatment with trimethylamine, it is possible to obtain rigid ion exchange polymers that behave like IEMs and allow only one charge type of ions to pass through, i.e., are permselective. We demonstrate successful open tubular cation chromatography suppressor performance.

  5. Development of long-lived radionuclide partitioning technology - Preparation of ion exchanges for selective separation of radioactive elements

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Si Joong; Jeong, Hae In; Shim, Min Sook [Korea University, Seoul (Korea, Republic of); Kim, Jeong [Seonam University, Namwon (Korea, Republic of)

    1995-07-01

    Ion exchanger contained nitrogen-oxygen donor macrocyclic units was synthesized, and immobilization process was carried out by adsorption of the exchanger to silica gel. The binding constants were measured with acid concentration. From the binding constants, selectivity for Pt(II) ion and acid concentration of eluents were determined. The most optimum conditions for the separation were also determined from investigating the effects of amount of immobile phase and column length. And liarit aza-crown ethers were synthesized and selectively separated Cs/Sr ion from mixed metal solution. 37= refs., 24 tabs., 40 figs. (author)

  6. UV laser induced desorption of CsI and RbI ion clusters

    Science.gov (United States)

    Fernández-Lima, F. A.; Ponciano, C. R.; Filho, H. D. Fonseca; Pedrero, E.; Chaer Nascimento, M. A.; da Silveira, E. F.

    2006-09-01

    Experimental results of laser sputtering of cesium and rubidium iodide secondary ions are presented. A TOF mass spectrometer, operating in linear mode, continuous extraction for positive or negative ions, was used for the analysis of (CsI) nCs +, (CsI) nI -, (RbI) nRb + and (RbI) nI - ion emission as a function of the laser irradiance. Experimental data show that the cluster ion emission yields decrease exponentially with n, for all the laser irradiances applied. Theoretical analysis of the clusters structure was performed using density functional theory at the B3LYP/LACV3P level, for the positive and negative cluster series. A quasi-equilibrium evolution of the clusters is proposed to extract a parameter characteristic of the cluster recombination process: the effective temperature. The hypothesis of the atomic species' recombination (during the expansion of a high density highly ionized cloud) leading to cluster formation is confirmed to some extent in a second set of experiments: the UV laser ablation of a mixed and non-mixed cesium iodide and potassium bromide targets. These experiments show that the emission yields contain contributions from both the recombination process and from the sample stoichiometry, even for high laser irradiances.

  7. Oxidation of H2 and CO over ion-exchanged X and Y zeolites.

    Science.gov (United States)

    Lahr, Daniel G; Li, Junhui; Davis, Robert J

    2007-03-21

    Zeolites X and Y exchanged with Group IA cations were synthesized by aqueous ion exchange of NaX and NaY and used as catalysts in the oxidation of H2 and CO at temperatures ranging from 473 to 573 K. The CsX zeolite was the most active material of the series for both reactions whereas HX was the least active. Moreover, the oxidation of CO in H2 was very selective (approximately 80%) over the alkali-metal exchanged materials. Isotopic transient analysis of CO oxidation during steady-state reaction at 573 K was used to evaluate the coverage of reactive carbon-containing intermediates that lead to product as well as the pseudo-first-order rate constant of the reaction. A factor of 4 enhancement in activity achieved by exchanging Cs for Na was attributed to a higher coverage of reactive intermediates in CsX because the pseudo-first-order rate constant was nearly same for the two materials (approximately 0.7 s(-1)). The number of reactive intermediates on both materials was orders of magnitude below the number of alkali metal cations in the zeolites but was similar to the number of impurity Fe atoms in the samples. Because the trend in Fe impurity loading was the same as that for oxidation activity, a role of transition metal impurities in zeolite oxidation catalysis is suggested.

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

    Science.gov (United States)

    Sökmen, Ilkay; Sevin, Fatma

    2003-08-01

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

  9. Study on actinoid isolation by antimonide ion exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Masamichi [Tokyo Inst. of Tech. (Japan). Faculty of Science; Kubota, Masumitsu; Yamagishi, Isao

    1996-01-01

    To establish a containment of long-life nuclides and an effective reduction of waste volume is important to reduce the loadings on the natural environment. Chemical isolation of radioactive nuclides from wastes was attempted by using inorganic ion exchanger with high specificity and thermal stability. In this study, titanium antimonide was used as an ion exchanger to investigate the adsorption of trivalent metallic ions according to Kielland plot curves. When the ionic equivalent fraction (X-bar{sub M}) was around 0.005, Kielland plot curve of either of 3-valent metallic ions was bent, suggesting the exchanger had two different adsorption sites. The slope of the curve became smaller as an elevation of temperature. These results show that the ion radius was decreased resulting from partial elimination of the hydrated water of ion and thus, the steric conditions around the exchange site might be improved. (M.N.)

  10. Local structures of ions at ion-exchange resin/solution interface.

    Science.gov (United States)

    Harada, Makoto; Okada, Tetsuo

    2005-08-26

    The local structures of Cl- and Br- in anion-exchange resins have been studied by X-ray absorption fine structure (XAFS), and separation selectivity is discussed on the basis of results. When two different anion-exchange resins having trimethylammonium and dimethylammonium groups as anion-exchange groups are employed for ion-exchange experiments, slightly higher Br- selectivity has been obtained with the former. XAFS has indicated that the average hydration numbers for a given anion is not affected by the structure of the ion-exchange group, but that the extent of ion-association between the anion and the ion-exchange groups depends on the type of the ion-exchange group. Shorter interaction distance (and in turn stronger ion-association) has been confirmed for the dimethylammonium-type resin, and is consistent with lower Br- selectivity of this resin.

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

    OpenAIRE

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

    2014-01-01

    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 co...

  12. Experimental and density functional theory study of the adsorption of N2O on ion-exchanged ZSM-5: part II. The adsorption of N2O on main-group ion-exchanged ZSM-5.

    Science.gov (United States)

    Zhang, Bo; Lu, Yongan; He, Hong; Wang, Jianguo; Zhang, Changbin; Yu, Yunbo; Xue, Li

    2011-01-01

    The adsorption and desorption of N2O on main-group ion-exchanged ZSM-5 was studied using temperature-programmed desorption (TPD) and density functional theory (DFT) calculations. TPD experiments were carried out to determine the desorbed temperature Tmax corresponding to the maximum mass intensity of N2O desorption peak and adsorption capacity of N2O on metal-ion-exchanged ZSM-5s. The results indicated that Tmax followed a sequence of Ba2+ > Ca2+ > Cs+ > K+ > Na+ > Mg2+ and the amount of adsorbed N2O on main-group metal cation followed a sequence of Ba2+ > Mg2+ > Ca2+ > Na+ > K+ > Cs+. The DFT calculations were performed to obtain the adsorption energy (Eads), which represents the strength of the interaction between metal cations and the N-end or O-end of N2O. The calculation results showed that the N-end of the N2O molecule was favorably adsorbed on ion-exchanged ZSM-5, except for Cs-ZSM-5. For alkali metal cations, the Eads of N2O on cations followed the order which was the same to that of Tmax: Cs+ > K+ > Na+. The calculated and experimental results consistently showed that the adsorption performances of alkaline-earth metal cations were better than those of alkali metal cations.

  13. Ion exchange model for α phase proton exchange waveguide in LiNbO3

    DEFF Research Database (Denmark)

    Veng, Torben Erik; Skettrup, Torben

    1998-01-01

    An H+/Li+ exchange model is found to be applicable to describe the diffusion of protons when optical waveguides are formed in LiNbO3 by proton exchange methods where the proton doped crystal structure stays in the pure α phase. The H + and Li+ self-diffusion coefficients in the ion exchange model...

  14. ION EXCHANGE MECHANISM OF Cr+3 ON NATURALLY OCCURRING CLINOPTILOLITE

    Directory of Open Access Journals (Sweden)

    M.A.S.D. de Barros

    1997-09-01

    Full Text Available Ion exchange isotherms are very important tools to achieve a better comprehension of cation removal by means of zeolite treatment. In this work, three isotherms were obtained (at 298K, at 313K and at 333K from natural pretreated Na+ clinoptilolite. The ion exchange was carried out with Cr+3 ions. The isotherms’ shape is similar to the classical type "b" isotherm, according to the arrangement proposed by Breck (1984. Mathematical fitting was applied to the experimental points (Table Curve software to obtain a representative curve thereof. From such fittings, points were simulated and then used to construct the Kielland plots, whose shape was associated with an ion exchange mechanism. Straight lines were obtained as an indication that, although the zeolite used is of natural occurrence and presents impurities such as mordenite and clays, only one site is involved in the ion exchange process

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

    Science.gov (United States)

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

    2014-06-01

    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.

  16. Radiation damage mechanisms in CsI(Tl) studied by ion beam induced luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Quaranta, Alberto [Dipartimento di Ingegneria dei Materiali e delle Tecnologie Industriali - DIMTI, Universita di Trento, Via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy)], E-mail: quaranta@ing.unitn.it; Gramegna, Fabiana; Kravchuk, Vladimir [Laboratori Nazionali di Legnaro - INFN, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy); Scian, Carlo [Dipartimento di Ingegneria dei Materiali e delle Tecnologie Industriali - DIMTI, Universita di Trento, Via Mesiano 77, I-38050 Povo, Trento (Italy); Laboratori Nazionali di Legnaro - INFN, Via dell' Universita 2, I-35020 Legnaro, Padova (Italy)

    2008-06-15

    Ion beam induced luminescence (IBIL) has been used to study the kinetics of defect production under ion beam irradiation in CsI(Tl) crystals with different Tl{sup +} concentrations (250, 560, 3250 and 6500 ppm). The crystals have been irradiated with H{sup +} and {sup 4}He{sup +} at 1.8 MeV. Both the scintillator spectra after irradiation and the intensity decrease at different wavelengths as a function of the fluence have been measured. The emission bands shift to higher wavelengths after irradiation, and the light decrease has been interpolated following a saturation model for the point defect concentration. Crystals with low Tl{sup +} concentrations present the UV emission peak of pure CsI at 300 nm whose intensity during H{sup +} irradiation and reaches a maximum under He{sup +} irradiation. At low Tl{sup +} concentrations the damage rate depends on the ion stopping power, while at higher concentrations it depends on the activator concentration. The results can be interpreted by assuming that the defects affecting the light emission are point defects nearby Tl{sup +} ions.

  17. Sers-Active Silver Nanoparticles in Ion-Exchanged Glass

    Science.gov (United States)

    Chen, Ya; Jaakola, Janne; Säynätjoki, Antti; Tervonen, Ari; Honkanen, Seppo

    We study synthesis and SERS activity of glass-embedded ion-exchanged silver nanoparticles formed by two different methods. Silver-sodium ion-exchange process with heat treatment was utilized on commercial microscope slides, while masked ion-exchange technique was performed on glass Corning 0211. The distribution of particles was studied by absorption spectroscopy and atomic force microscopy. After etching the glass surface to expose the particles, SERS performance of these particles was investigated with micro-Raman spectroscopy using Rhodamine 6G as the analyte.

  18. Ion-exchanged glass waveguide technology: a review

    Science.gov (United States)

    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.

  19. Superheated water ion-exchange chromatography: an experimental approach for interpretation of separation selectivity in ion-exchange processes.

    Science.gov (United States)

    Shibukawa, Masami; Shimasaki, Tomomi; Saito, Shingo; Yarita, Takashi

    2009-10-01

    Cation-exchange selectivity for alkali and alkaline-earth metal ions and tetraalkylammonium ions on a strongly acidic sulfonic acid cation-exchange resin has been investigated in the temperature range of 40-175 degrees C using superheated water chromatography. Dependence of the distribution coefficient (ln KD) on the reciprocal of temperature (1/T) is not linear for most of the ions studied, and the selectivity coefficient for a pair of alkali metal ions or that of alkaline-earth metal ions approaches unity as temperature increases. On the other hand, the retention order of tetraalkylammonium ions is reversed at 160 degrees C or above when eluted with Na2SO4 aqueous solution and the larger ions are eluted faster than the smaller ones contrary to the retention order obtained at ambient temperature. The change in ion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions and specific adsorption or distribution of ionic species between the external solution and ion-exchange resin. In superheated water, the electrostatic interaction or association of the ions with the fixed ion becomes a predominant mechanism resulting in different separation selectivity from that obtained at ambient temperature.

  20. Trends in Effective Diffusion Coefficients for Ion-Exchange Strengthening of Soda-Lime-Silicate Glasses

    Directory of Open Access Journals (Sweden)

    Stefan Karlsson

    2017-04-01

    Full Text Available Monovalent cations enable efficient ion-exchange processes due to their high mobility in silicate glasses. Numerous properties can be modified in this way, e.g., mechanical, optical, electrical, or chemical performance. In particular, alkali cation exchange has received significant attention, primarily with respect to introducing compressive stress into the surface region of a glass, which increases mechanical durability. However, most of the present applications rely on specifically tailored matrix compositions in which the cation mobility is enhanced. This largely excludes the major area of soda-lime-silicates (SLS such as are commodity in almost all large-scale applications of glasses. Basic understanding of the relations between structural parameters and the effective diffusion coefficients may help to improve ion-exchanged SLS glass products, on the one hand in terms of obtainable strength and on the other in terms of cost. In the present paper, we discuss the trends in the effective diffusion coefficients when exchanging Na+ for various monovalent cations (K+, Cu+, Ag+, Rb+, and Cs+ by drawing relations to physicochemical properties. Correlations of effective diffusion coefficients were found for the bond dissociation energy and the electronic cation polarizability, indicating that localization and rupture of bonds are of importance for the ion-exchange rate.

  1. Trends in Effective Diffusion Coefficients for Ion-exchange Strengthening of Soda Lime Silicate Glasses

    Science.gov (United States)

    Karlsson, Stefan; Wondraczek, Lothar; Ali, Sharafat; Jonson, Bo

    2017-04-01

    Monovalent cations enable efficient ion exchange processes due to their high mobility in silicate glasses. Numerous properties can be modified in this way, e.g., mechanical, optical, electrical or chemical performance. In particular, alkali cation exchange has received significant attention, primarily with respect to introducing compressive stress into the surface region of a glass, which increases mechanical durability. However, most of the present applications rely on specifically tailored matrix compositions in which the cation mobility is enhanced. This largely excludes the major area of soda lime silicates (SLS) such as are commodity in almost all large-scale applications of glasses. Basic understanding of the relations between structural parameters and the effective diffusion coefficients may help to improve ion-exchanged SLS glass products, on the one hand in terms of obtainable strength and on the other in terms of cost. In the present paper, we discuss the trends in the effective diffusion coefficients when exchanging Na+ for various monovalent cations (K+, Cu+, Ag+, Rb+ and Cs+) by drawing relations to physico-chemical properties. Correlations of effective diffusion coefficients were found for the bond dissociation energy and the electronic cation polarizability, indicating that localization and rupture of bonds are of importance for the ion exchange rate.

  2. Decontamination and dismantlement of the building 594 waste ion exchange facility at Argonne National Laboratory-East project final report.

    Energy Technology Data Exchange (ETDEWEB)

    Wiese, E. C.

    1998-11-23

    The Building 594 D&D Project was directed toward the following goals: Removal of any radioactive and hazardous materials associated with the Waste Ion Exchange Facility; Decontamination of the Waste Ion Exchange Facility to unrestricted use levels; Demolition of Building 594; and Documentation of all project activities affecting quality (i.e., waste packaging, instrument calibration, audit results, and personnel exposure) These goals had been set in order to eliminate the radiological and hazardous safety concerns inherent in the Waste Ion Exchange Facility and to allow, upon completion of the project, unescorted and unmonitored access to the area. The ion exchange system and the resin contained in the system were the primary areas of concern, while the condition of the building which housed the system was of secondary concern. ANL-E health physics technicians characterized the Building 594 Waste Ion Exchange Facility in September 1996. The characterization identified a total of three radionuclides present in the Waste Ion Exchange Facility with a total activity of less than 5 {micro}Ci (175 kBq). The radionuclides of concern were Co{sup 60}, Cs{sup 137}, and Am{sup 241}. The highest dose rates observed during the project were associated with the resin in the exchange vessels. DOE Order 5480.2A establishes the maximum whole body exposure for occupational workers at 5 rem (50 mSv)/yr; the administrative limit at ANL-E is 1 rem/yr (10 mSv/yr).

  3. Tc-99 Ion Exchange Resin Testing

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-08-01

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

  4. Laser ablation of metal surfaces contaminated with Cs{sup +} ions

    Energy Technology Data Exchange (ETDEWEB)

    Won, H. J.; Baigalmaa, B.; Moon, J. K.; Jung, C. H.; Lee, K. W. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Hyun, J. H. [Chungnam National University, Daejeon (Korea, Republic of)

    2009-05-15

    Laser cleaning is a relatively recent technique for removing pollutants from surfaces that is currently finding applications in many fields. In a nuclear industry, there is a great interest to develop an efficient dry decontamination process. During the application of the dry decontamination process, the generation of a secondary waste is negligible. The radioactivity of hot cells in the DFDF (Dupic Fuel Development Facility) is presumed to be high and the predominant radionuclide is Cs-137. A Q-switched Nd:YAG laser with a 1064nm and 450 mJ/pulse was employed to study the decontamination characteristics of type 304 stainless steel specimens artificially contaminated with Cs{sup +} ion. Decontamination characteristics analyzed by SEM and EPMA.

  5. A multi-sample Cs-sputter negative-ion source

    Energy Technology Data Exchange (ETDEWEB)

    Alton, G.D.; Cui, B.; Bao, Y.; Reed, C.A.; Ball, J.A.; Williams, C. (Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6368 (United States))

    1999-04-01

    A multi-sample Cs sputter negative-ion source, equipped with a conical-geometry, W-surface-ionizer has been designed and fabricated that permits sample changes without disruption of on-line accelerator operation. Sample changing is effected by actuating an electro-pneumatic control system located at ground potential that drives an air-motor-driven sample-indexing-system mounted at high voltage; this arrangement avoids complications associated with indexing mechanisms that rely on electronic power-supplies located at high potential. In-beam targets are identified by LED indicator lights derived from a fiber-optic, Gray-code target-position sensor. Aspects of the overall source design and details of the indexing mechanism along with operational parameters, ion optics, intensities, and typical emittances for a variety of negative-ion species will be presented in this report. [copyright] [ital 1999 American Institute of Physics.

  6. Storage and Aging Effects on Spherical Resorcinol-Formaldehyde Resin Ion Exchange Performance

    Energy Technology Data Exchange (ETDEWEB)

    Fiskum, Sandra K.; Arm, Stuart T.; Edwards, Matthew K.; Steele, Marilyn J.; Thomas, Kathie K.

    2007-09-10

    Bechtel National, Inc. (BNI) is evaluating the alternate Cs ion exchanger, spherical resorcinol-formaldehyde (RF), for use in the River Protection Project-Waste Treatment Plant (RPP-WTP).( ) Previous test activities with spherical RF indicate that it has adequate capacity, selectivity, and kinetics to perform in the plant according to the flowsheet needs. It appears to have better elution and hydraulic properties than the existing alternatives: ground-gel RF and SuperLig® 644 (SL 644).( ) To date, the spherical RF performance testing has been conducted on freshly manufactured resin (within ~2 months of manufacture). The ion exchange resins will be manufactured and shipped to the WTP up to 1 year before being used in the plant. Changes in the resin properties during storage could reduce the capacity of the resin to remove Cs from low-activity waste solutions. Active sites on organic SL-644 resin have been shown to degrade during storage (Arm et al. 2004). Additional testing was needed to study the effects of storage conditions and aging on spherical RF ion exchange performance. Variables that could have a significant impact on ion exchange resins during storage include storage temperature, medium, and time. Battelle—Pacific Northwest Division (PNWD) was contracted to test the effects of various storage conditions on spherical RF resin. Data obtained from the testing will be used by the WTP operations to provide direction for suitable storage conditions and manage the spherical RF resin stock. Storage test conditions included wet and dry resin configurations under nitrogen at three temperatures. Work was initially conducted under contract number 24590-101-TSA-W000-00004 satisfying the needs defined in Appendix C of the Research and Technology Plan( ) TSS A-219 to evaluate the impact of storage conditions on RF resin performance. In February 2007, the contract mechanism was switched to Pacific Northwest National Laboratory (PNNL) Operating Contract DE-AC05-76RL

  7. Separation processes in biotechnology. Ion-exchange processes.

    Science.gov (United States)

    Shuey, C D

    1990-01-01

    Through the use of several differentiating mechanisms, ion exchangers can separate ionic and nonionic materials, solutions containing only ionic species, and even completely nonionic mixtures. Although the mechanisms are distinct in their mode of operation, the resin characteristics that influence the results are largely the same. A practical understanding of the resin properties involved is all that is necessary to begin to use ion-exchange resins successfully. Ion exchange owes most of its history to water treatment, which has provided the economic and technological driving force in the past for the development of improved resins. However, specialty applications such as those in biotechnology are steadily becoming major factors in industry, perhaps not in shear volumes of resin used, but certainly in the value added by the process. The field of biotechnology no doubt holds many of the exciting new applications for ion exchange.

  8. Modeling radial flow ion exchange performance for condensate polisher conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shallcross, D. [University of Melbourne, Melbourne, VIC (Australia). Department of Chemical Engineering; Renouf, P.

    2001-11-01

    A theoretical model is developed which simulates ion exchange performance within an annular resin bed. Flow within the mixed ion exchange bed is diverging, with the solution flowing outwards away from the bed's axis. The model is used to simulate performance of a mixed annular bed operating under condensate polisher conditions. The simulation predictions are used to develop design envelope curves for practical radial flow beds and to estimate potential cost savings flowing from less expensive polisher vessels. (orig.)

  9. Samarium Ion Exchanged Montmorillonite for High Temperature Cumene Cracking Reaction

    Science.gov (United States)

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

    2011-02-01

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

  10. Samarium Ion Exchanged Montmorillonite for High Temperature Cumene Cracking Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Binitha, N N; Silija, P P; Yaakob, Z [Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, National University of Malaysia, 43600 UKM Bangi, Selangor (Malaysia); School of Materials Engineering, Universiti Malaysia Perlis, Taman Muhibah, 02600, Jejawi, Perlis (Malaysia); Suraj, V [Department of Applied Chemistry, CUSAT, Cochin 22, Kerala (India); Sugunan, S, E-mail: binithann@yahoo.co.in [National Institute of Technology, Calicut, Kerala (India)

    2011-02-15

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

  11. Recent advances in polymer monoliths for ion-exchange chromatography.

    Science.gov (United States)

    Nordborg, Anna; Hilder, Emily F

    2009-05-01

    The use of polymeric materials in ion-exchange chromatography applications is advantageous because of their typically high mechanical stability and tolerance of a wide range of pH conditions. The possibility of using polymeric monoliths in ion-exchange chromatography is therefore obvious and many of the same strategies developed for polymeric particles have been adapted for use with polymeric monoliths. In this review different strategies for the synthesis of polymeric monoliths with ion-exchange functionality are discussed. The incorporation of ion-exchange functionality by co-polymerization is included, as also are different post-polymerization alterations to the monolith surface such as grafting. The formulations and strategies presented include materials intended for use in analytical separations in ion-exchange chromatography, sample pre-treatment or enrichment applications, and materials for capillary electrochromatography. Finally, examples of the use of polymeric monoliths in ion-exchange chromatography applications are included with examples published in the years 2003 to 2008.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Synthesis and characterization of cesium molybdo vanado phosphate immobilized on platelet SBA-15: An efficient inorganic composite ion-exchanger for gadolinium ion sorption

    Energy Technology Data Exchange (ETDEWEB)

    Aghayan, H., E-mail: hasanaghayan@yahoo.com [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Tehran (Iran, Islamic Republic of); Khanchi, A.R., E-mail: akhanchi@aeoi.org.ir [Nuclear Science and Technology Institute, P.O. Box. 11365-8486, Tehran (Iran, Islamic Republic of); Mahjoub, A.R. [Department of Chemistry, Tarbiat Modares University, P.O. Box. 14155-4383, Tehran (Iran, Islamic Republic of)

    2013-06-01

    A series of cesium molybdo vanado phosphate (CsMVP) supported on platelet SBA-15 (SBA-15–%xCsMVP, x = 20, 30, 40 and 50 wt.%) was synthesized to develop an efficient inorganic composite ion-exchanger for gadolinium ion removal from aqueous solution. The preparation has been carried out using two-step aqueous impregnation methods. The obtained products were characterized by inductively coupled plasma (ICP), XRD, N{sub 2} adsorption–desorption isotherms, scanning electron microscopy (SEM) and FT-IR. In order to examine adsorption behavior of this compound on gadolinium removal, the effect of heteropoly metalate loading, pH, contact time, concentration of metal ion and temperature were investigated under batch system conditions. The SBA-15–30%CsMVP showed maximum adsorption capacity toward gadolinium removal. The results suggested that this methodology provides the general synthesis of supported heteropolymetalate with large surface areas, and ordered nano porous structures that can be used as inorganic composite ion-exchanger for efficient removal of gadolinium ions from aqueous solution.

  14. EXPLORING THE MAXWELL-STEFAN DESCRIPTION OF ION-EXCHANGE

    NARCIS (Netherlands)

    WESSELINGH, JA; VONK, P; KRAAIJEVELD, G

    1995-01-01

    In ion exchange, water and several ions diffuse simultaneously, with different velocities. They are driven by activity, electrical and pressure gradients. We describe these complicated processes with the Maxwell-Stefan equation. This equation for multicomponent diffusion requires one diffusivity or

  15. Small-Column Cesium Ion Exchange Elution Testing of Spherical Resorcinol-Formaldehyde

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-21

    This report summarizes the work performed to evaluate multiple, cesium loading, and elution cycles for small columns containing SRF resin using a simple, high-level waste (HLW) simulant. Cesium ion exchange loading and elution curves were generated for a nominal 5 M Na, 2.4E-05 M Cs, 0.115 M Al loading solution traced with 134Cs followed by elution with variable HNO3 (0.02, 0.07, 0.15, 0.23, and 0.28 M) containing variable CsNO3 (5.0E-09, 5.0E-08, and 5.0E-07 M) and traced with 137Cs. The ion exchange system consisted of a pump, tubing, process solutions, and a single, small ({approx}15.7 mL) bed of SRF resin with a water-jacketed column for temperature-control. The columns were loaded with approximately 250 bed volumes (BVs) of feed solution at 45 C and at 1.5 to 12 BV per hour (0.15 to 1.2 cm/min). The columns were then eluted with 29+ BVs of HNO3 processed at 25 C and at 1.4 BV/h. The two independent tracers allowed analysis of the on-column cesium interaction between the loading and elution solutions. The objective of these tests was to improve the correlation between the spent resin cesium content and cesium leached out of the resin in subsequent loading cycles (cesium leakage) to help establish acid strength and purity requirements.

  16. Advanced ion exchange resins for PWR condensate polishing

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, B. [Rohm and Haas Co. (United States); Tsuzuki, S. [Rohm and Haas Co. (Japan)

    2002-07-01

    The severe chemical and mechanical requirements of a pressurized water reactor (PWR) condensate polishing plant (CPP) present a major challenge to the design of ion exchange resins. This paper describes the development and initial operating experience of improved cation and anion exchange resins that were specifically designed to meet PWR CPP needs. Although this paper focuses specifically on the ion exchange resins and their role in plant performance, it is also recognized and acknowledged that excellent mechanical design and operation of the CPP system are equally essential to obtaining good results. (authors)

  17. Reduction behavior of cerium(Ⅲ) ions in NaCl-2CsCl melt

    Institute of Scientific and Technical Information of China (English)

    QI Xue; ZHU Hongmin

    2005-01-01

    The cathodic process of cerium(Ⅲ) ions in NaCl-2CsCl melt was studied by cyclic voltammetry and square wave voltammetry with tungsten and gold electrodes at 873 K. The two electroanalytical methods yield similar results. The cathodic process of cerium(Ⅲ) ions consists of two reversible steps: Ce3+ + e-= Ce2+ and Ce2+ + 2e-= Ce. The half wave potentials of Ce3+/Ce2+ and Ce2+/Ce were determined as -2.525 V vs. Cl2/Cl- and -2.975 V vs. Cl2/Cl-, respectively. The diffusion coefficient of Ce3+ was also determined as 5.5 × 10-5 cm2·s-1.

  18. Determination of Sc by Ion-exchanger Colorimetry

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Ion-exchanger colorimetry for scandium in the form of ternary color system "Sc(Ⅲ)-CPA-pc-Ac" was developed. The influences of types and grain sizes of resin, adsorption modes and the acidity on the determination were studied systematically, and the optimum operating conditions and the allowable amounts of foreign ions were determined. In comparison with the ordinary solution colorimetry, both of the sensitivity and the selectivity of this ion-exchanger colorimetry are improved obviously. The preliminary uses of this method to the determination of Sc(Ⅲ) in two synthetic samples were satisfied.

  19. Rate theory on water exchange in aqueous uranyl ion

    Science.gov (United States)

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

    2017-03-01

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

  20. Negative Joule Heating in Ion-Exchange Membranes

    OpenAIRE

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

    2014-01-01

    In ion-exchange membrane processes, ions and water flow under the influence of gradients in hydrostatic pressure, ion chemical potential, and electrical potential (voltage), leading to solvent flow, ionic fluxes and ionic current. At the outer surfaces of the membranes, electrical double layers (EDLs) are formed (Donnan layers). When a current flows through the membrane, we argue that besides the positive Joule heating in the bulk of the membrane and in the electrolyte outside the membrane, t...

  1. Multi-region Transport and Competitive Ion Exchange in Partially Saturated Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Yabusaki, Steven B.(BATTELLE (PACIFIC NW LAB)); Gamerdinger, Amy P.(WASHINGTON STATE UNIV TC); S.M. Hassanizadeh, R.J. Schotting, et al.

    2002-01-01

    In most natural subsurface settings cesium sorbs very strongly to sediments, effectively limiting its transport. At the Hanford Site in Washington State (USA), vadose zone migration of 137Cs from subsurface high-level radioactive waste tanks has been detected over 40 meters below the ground surface. Batch and saturated laboratory column studies provided the basis for a quantitative multisite, multicomponent ion exchange model of Cs+ competition with Na+, K+, Ca++, and Mg++ in a composite Hanford soil. The validity of this model under unsaturated conditions was examined in a series of reactive transport column experiments performed in an ultracentrifuge at different liquid saturations. For each experiment, a constant, uniform saturation was maintained using a steady influx of a 5 M sodium nitrate solution with 5.4E-5 M cesium iodide. Of interest was the potential for enhanced cesium transport due to the presence of immobile liquid and/or bypassed regions. Mobile and immobile fluid fractions, dispersion, and the rate of mass transfer between mobile and immobile regions were determined from the tracer breakthrough. At higher saturations ({approx} 65%), the tracer and cesium behavior could be predicted to a large degree using a single mobile region with the previously developed multicomponent ion exchange model. At lower saturations ({approx} 23%), however, the tracer breakthrough indicated a relatively large immobile fluid fraction, which could be described with a multi-region approach. In this experiment, cesium broke through earlier and at higher concentrations than predicted by multi-region theory combined with the existing cesium ion exchange model. This behavior is consistent with a higher density of exchange sites in the immobile fluid region.

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

    Energy Technology Data Exchange (ETDEWEB)

    Alsobrook, A. N.; Hobbs, D. T.

    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.

  3. Ion-exchange chromatographic analysis of peroxynitric acid.

    Science.gov (United States)

    Nakashima, Yoichi; Ikawa, Satoshi; Tani, Atsushi; Kitano, Katsuhisa

    2016-01-29

    Ion-exchange chromatographic analysis of peroxynitric acid (O2NOOH) was performed by combining an acidic eluate with an UV-vis detector and immersing the separation column in an ice-water bath. The decomposition behavior of peroxynitric acid in the solution was also studied using this system. The fraction for the peroxynitric acid peak was collected. Ion-exchange chromatographic analysis of this fraction, after standing at room temperature for 24h, showed that the decomposition products were mainly nitrate ions with a very small amount of nitrous acid. The peroxynitric acid peak area correlated perfectly with the total amount of decomposition products. The ion-exchange chromatographic isolation allowed us to evaluate the molar extinction coefficient of peroxynitric acid precisely in a wider wavelength range than previous reports. The value decreases monotonically from 1729±26M(-1)cm(-1) at 200nm to 12.0±0.5M(-1)cm(-1) at 290nm.

  4. Involvement of DNA-PK(sub cs) in DSB Repair Following Fe-56 Ion Irradiation

    Science.gov (United States)

    O'Neill, Peter; Harper, Jane; Anderson, Jennifer a.; Cucinnota, Francis A.

    2007-01-01

    When cells are exposed to radiation, cellular lesions are induced in the DNA including double strand breaks (DSBs), single strand breaks and clustered DNA damage, which if not repaired with high fidelity may lead to detrimental biological consequences. Complex DSBs are induced by ionizing radiation and characterized by the presence of base lesions close to the break termini. They are believed to be one of the major causes of the biological effects of IR. The complexity of DSBs increases with the ionization density of the radiation and these complex DSBs are distinct from the damage induced by sparsely ionizing gamma-radiation. It has been hypothesized that complex DSBs produced by heavy ions in space pose problems to the DNA repair machinery. We have used imm uno-cyto-chemical staining of phosphorylated histone H2AX (gamma-H2AX) foci, as a marker of DSBs. We have investigated the formation and loss of gamma-H2AX foci and RAD51 foci (a protein involved in the homologous recombination pathway) in mammalian cells induced by low fluences of low-LET gamma-radiation and high-LET Fe-56 ions (1GeV/n, 151 keV/micron LET). M059J and M059K cells, which are deficient and proficient in DNA-PK(sub cs) activity respectively, were used to examine the role of DNA-PK(sub cs), a key protein in the non-homologous end joining (NHEJ) pathway of DSB repair, along with HF19 human fibroblasts. Followi ng irradiation with Fe-56 ions the rate of repair was slower in M059J cells compared with that in M059K, indicating a role for DNA-PK(sub cs) in the repair of DSB induced by Fe-56 ions. However a small percentage of DSBs induced are rejoined within 5 h although many DSBs still persist up to 24 h. When RAD51 was examined in M059J/K cells, RAD51 foci are visible 24 hours after irradiation in approximately 40% of M059J cells compared with DSB induced by 56Fe ions. Vanillin, an inhibitor of DNA-PK(sub cs), reduces significantly the rate of DSB repair in HF19 cells following 1 Gy gamma

  5. Study on the permselectivity of ion exchange membrane

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Ion exchange membranes with high permselectivity (the character of separating cations from anions or anions from cations) and high selectivity (the character of separating cations or anions of different valencies) are important for electrodialysis process. The Donnan equilibrium theory, based on the equilibrium of ions and no electric field, can not exactly explain the permselectivity of ion exchange membrane for ED process, since it is impossible to set up a ion exchange equilibrium between membrane and solution and to neglect the influence of electrical driving force on ions during ED process. A novel model named "anti-electric potential " is established to interpret the permselectivity of ion exchange membrane, according to the determination of electric potential between membranes and the variation of elements content in solutions and membranes. The results of experiment prove that the "anti-electric potential" really exists within membranes. As for the selectivity, the results reveal that electric potential and hydration energy have great influence on the concentration and mobility of ions in membranes.

  6. A G-pentaplex-based assay for Cs(+) ions in aqueous solution using a luminescent Ir(III) complex.

    Science.gov (United States)

    Lin, Sheng; Yang, Chao; Mao, Zhifeng; He, Bingyong; Wang, Yi-Tao; Leung, Chung-Hang; Ma, Dik-Lung

    2016-03-15

    A series of 5 randomly designed in-house cyclometalated Ir(III) complexes were examined for their application in G-pentaplex probes and the "proof-of-principle" concept in G-pentaplex-based Cs(+) ions detection. The G-pentaplex-forming sequence (DNA1, 5'-T(iG)4T-3', where iG=isoguanine) is present in single strand DNA form ab initio, however, the addition of Cs(+) ions lead to formation of the intermolecular G-pentaplex structure which is identified by the novel Ir(III) complex 1 afterward and produce an enhanced luminescence signal for Cs(+) ions monitoring. To the best of our knowledge, this is the first G-pentaplex probe and also the first G-pentaplex-based label-free detection platform for Cs(+) ions reported in the literature. The monitoring of spiked Cs(+) ions in natural water samples demonstrates the potential application and technical sound of this "proof-of-principle" concept sensing platform.

  7. Involvement of DNA-PK(sub cs) in DSB Repair Following Fe-56 Ion Irradiation

    Science.gov (United States)

    O'Neill, Peter; Harper, Jane; Anderson, Jennifer a.; Cucinnota, Francis A.

    2007-01-01

    When cells are exposed to radiation, cellular lesions are induced in the DNA including double strand breaks (DSBs), single strand breaks and clustered DNA damage, which if not repaired with high fidelity may lead to detrimental biological consequences. Complex DSBs are induced by ionizing radiation and characterized by the presence of base lesions close to the break termini. They are believed to be one of the major causes of the biological effects of IR. The complexity of DSBs increases with the ionization density of the radiation and these complex DSBs are distinct from the damage induced by sparsely ionizing gamma-radiation. It has been hypothesized that complex DSBs produced by heavy ions in space pose problems to the DNA repair machinery. We have used imm uno-cyto-chemical staining of phosphorylated histone H2AX (gamma-H2AX) foci, as a marker of DSBs. We have investigated the formation and loss of gamma-H2AX foci and RAD51 foci (a protein involved in the homologous recombination pathway) in mammalian cells induced by low fluences of low-LET gamma-radiation and high-LET Fe-56 ions (1GeV/n, 151 keV/micron LET). M059J and M059K cells, which are deficient and proficient in DNA-PK(sub cs) activity respectively, were used to examine the role of DNA-PK(sub cs), a key protein in the non-homologous end joining (NHEJ) pathway of DSB repair, along with HF19 human fibroblasts. Followi ng irradiation with Fe-56 ions the rate of repair was slower in M059J cells compared with that in M059K, indicating a role for DNA-PK(sub cs) in the repair of DSB induced by Fe-56 ions. However a small percentage of DSBs induced are rejoined within 5 h although many DSBs still persist up to 24 h. When RAD51 was examined in M059J/K cells, RAD51 foci are visible 24 hours after irradiation in approximately 40% of M059J cells compared with Vanillin, an inhibitor of DNA-PK(sub cs), reduces significantly the rate of DSB repair in HF19 cells following 1 Gy gamma-radiation but at 0.25 Gy gamma

  8. Cementation of residue ion exchange resins at Rocky Flats

    Energy Technology Data Exchange (ETDEWEB)

    Dustin, D.F.; Beckman, T.D.; Madore, C.M.

    1998-03-03

    Ion exchange resins have been used to purify nitric acid solutions of plutonium at Rocky Flats since the 1950s. Spent ion exchange resins were retained for eventual recovery of residual plutonium, typically by incineration followed by the aqueous extraction of plutonium from the resultant ash. The elimination of incineration as a recovery process in the late 1980s and the absence of a suitable alternative process for plutonium recovery from resins led to a situation where spent ion exchange resins were simply placed into temporary storage. This report describes the method that Rocky Flats is currently using to stabilize residue ion exchange resins. The objective of the resin stabilization program is: (1) to ensure their safety during interim storage at the site, and (2) to prepare them for ultimate shipment to the Waste Isolation Pilot Plant (WIPP) in New Mexico. Included in the discussion is a description of the safety concerns associated with ion exchange resins, alternatives considered for their stabilization, the selection of the preferred treatment method, the means of implementing the preferred option, and the progress to date.

  9. Effects of ion-exchange treatment on bromate formation and oxidation efficiency during ozonation

    OpenAIRE

    Echigo, S.; Itoh, S.; Niwa, A

    2012-01-01

    Ion-exchange treatment is a promising technique for removing hydrophilic compounds during drinking water treatment. In this study, we applied several different ion exchangers (i.e., anion exchange resins and a hydrotalcite compound) to bromide removal to minimize bromate formation during ozonation. It was found that ion-exchange treatment affected ozone and hydroxyl radical concentration profiles as well as bromate ion concentration after ozonation. Selecting an appropriate ion exchanger is i...

  10. Literature Review of Spherical Resorcinol-Formaldehyde for Cesium Ion Exchange

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Garrett N.

    2014-09-30

    The current report summarizes work performed throughout the scientific community and DOE complex as reported in the open literature and DOE-sponsored reports to evaluate the Cs+ ion exchange (CIX) characteristics of SRF resin. King (2007) completed a similar literature review in support of material selection for the Small Column Ion Exchange (SCIX) project. Josephson et al. (2010) and Sams et al. (2009) provided a similar brief review of SRF CIX for the near-tank Cs+ removal (NTCR) project. Thorson (2008a) documented the basis for recommending SRF over SuperLigTM 644 as the primary CIX resin in the WTP. The current review expands on previous work, summarizes additional work completed to date, and provides a broad view of the literature without focusing on a specific column system. Although the focus of the current review is the SRF resin, many cited references include multiple materials such as the non-spherical GGRF and SuperLigTM 644 organic resins and crystalline silicotitanate (CST) IONSIVTM IE-911, a non-elutable inorganic material. This report summarizes relevant information provided in the literature.

  11. THERMODYNAMICS OF ION-EXCHANGED NATURAL CLINOPTILOLITE

    Science.gov (United States)

    Natural clinoptilolite from Castle Creek, Idaho, and its cation-exchanged variants (Na-Cpt, NaK-Cpt, K-Cpt, and Ca-Cpt) were studied by high-temperature calorimetry. The hydration enthalpy for all clinoptilolites is about -30 kJ/mol H2O (liquid water reference state) at 25 C. T...

  12. Cesium leaching from {gamma}-irradiated CsA and CsX zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Enrique [Universidad Autonoma Metropolitana, Iztapalapa, A. P. 55-532, Av. San Rafael Atlixco No. 186 Col. Vicentina, 09340 Mexico, D.F. (Mexico)], E-mail: lima@xanum.uam.mx; Ibarra, Ilich A.; Lara, Victor [Universidad Autonoma Metropolitana, Iztapalapa, A. P. 55-532, Av. San Rafael Atlixco No. 186 Col. Vicentina, 09340 Mexico, D.F. (Mexico); Bosch, Pedro [Instituto de Investigaciones en Materiales, A. P. 70-360, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, 04510 Mexico, D.F. (Mexico); Bulbulian, Silvia [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, Col. Escandon, Delegacion Miguel Hidalgo, 11801 Mexico, D.F. (Mexico)

    2008-12-30

    The present study discusses the effect of {gamma}-irradiation on Cs{sup +}-exchanged X and A zeolites. The incorporation of Cs{sup +} ions into A and X zeolites was performed using three different cesium salts (chloride, nitrate or acetate). Cs{sup +} ions immobilized into the vitrified zeolites by thermal treatment are located in different sites of the zeolite networks. It is found that {gamma}-irradiation favors cesium retention depending on the cesium precursor salt used in the cationic exchange step.

  13. Phosphorus-contained polycondensation type ion-exchange resins

    Directory of Open Access Journals (Sweden)

    Tulkun Tursunov

    2012-06-01

    Full Text Available This work describes synthesis and research of new polycondensation type phosphorus-contained ion-exchange polymers by phosphorylation of polymers received through the interaction of furfural (accessible and cheap product of hydrolytic and cotton scraping industry of Uzbekistan with benzyl bromide (chloride. Furfural and its derivatives possess high reactionary ability thanks to presence of carbonyl groups, and presence of a heterocyclic cycle gives to the received polymers high thermal and chemical stability. Polycondensation reaction kinetics of furfural and benzyl bromide, and phosphorylation reaction of the received benzyl bromide-furfural polymer were studied. Sorption, kinetic and thermo-chemical properties of received ion-exchange resins were studied using physico-chemical and chemical analyses to find out specific objects of practical application. Particularly, sorption and selective properties of received ion-exchange resins to ions of such metals as copper, nickel, calcium, magnesium, and uranyl ion were studied. Received results support the application of the investigated ion-exchange resins in processes of clearing of industrial and waste waters of hydrometallurgical manufactures.

  14. Estimation of Sputtering Damages on a Magnetron H- Ion Source Induced by Cs+ and H+ Ions

    CERN Document Server

    Pereira, H; Alessi, J; Kalvas, t

    2013-01-01

    An H− ion source is being developed for CERN’s Linac4 accelerator. A beam current requirement of 80 mA and a reliability above 99% during 1 year with 3 month uninterrupted operation periods are mandatory. To design a low-maintenance long life-time source, it is important to investigate and understand the wear mechanisms. A cesiated plasma discharge ion source, such as the BNL magnetron source, is a good candidate for the Linac4 ion source. However, in the magnetron source operated at BNL, the removal of material from the molybdenum cathode and the stainless steel anode cover plate surfaces is visible after extended operation periods. The observed sputtering traces are shown to result from cesium vapors and hydrogen gas ionized in the extraction region and subsequently accelerated by the extraction field. This paper presents a quantitative estimate of the ionization of cesium and hydrogen by the electron and H− beams in the extraction region of BNL’s magnetron ion source. The respective contributions o...

  15. MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Evaluation of electrochemical ion exchange for cesium elution

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-01

    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 eluting solution is not in direct contact with the ion exchange material, very small volumes of the eluting solution can be used in a complete recycle mode in order to minimize the total volume of the cesium elute. In addition, the cesium is eluted as an alkaline solution that does not require neutralization with caustic to meet the tank farm specifications. Other advantages include easy incorporation of the electrochemical elution process into the present cesium recovery schemes.

  17. Optical properties of Mn3+ ions in Cs2NaAlF6 and Cs2NaGaF6 single crystals

    Science.gov (United States)

    da Fonseca, R. J. M.; Sosman, L. P.; Camara, A. R.

    2017-02-01

    The optical properties of Mn3+ ions in the elpasolites Cs2NaGaF6 and Cs2NaAlF6 have been investigated by absorption spectroscopy at 4.2 K. The absorption spectra are dominated by the spin-allowed 5E → 5T2 transition and the transition between the two Jahn-Teller components of the 5E level. The crystal-field parameter Dq was determined and a low crystal-field situation was established for both Mn3+-doped fluorides. The Jahn-Teller stabilization energies of the 5E and 5T2 levels were calculated and the obtained values shown a strong Jahn-Teller splitting in the 5E ground state.

  18. Catalysis using hydrous metal oxide ion exchanges

    Science.gov (United States)

    Dosch, Robert G.; Stephens, Howard P.; Stohl, Frances V.

    1985-01-01

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

  19. Catalysis using hydrous metal oxide ion exchangers

    Science.gov (United States)

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

    1983-07-21

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

  20. Adsorption of CO2, N2, and CH4 in Cs-exchanged chabazite: A combination of van der Waals density functional theory calculations and experiment study

    Science.gov (United States)

    Shang, Jin; Li, Gang; Singh, Ranjeet; Xiao, Penny; Danaci, David; Liu, Jefferson Z.; Webley, Paul A.

    2014-02-01

    The crucial role of dispersion force in correctly describing the adsorption of some typical small-size gas molecules (e.g., CO2, N2, and CH4) in ion-exchanged chabazites has been investigated at different levels of theory, including the standard density functional theory calculation using the Perdew, Burke, and Ernzerhof (PBE) exchange-correlation functional and van der Waals density functional theory (vdWDFT) calculations using different exchange-correlation models - vdW_DF2, optB86b, optB88, and optPBE. Our results show that the usage of different vdWDFT functionals does not significantly change the adsorption configuration or the profile of static charge rearrangement of the gas-chabazite complexes, in comparison with the results obtained using the PBE. The calculated values of adsorption enthalpy using different functionals are compared with our experimental results. We conclude that the incorporation of dispersion interaction is imperative to correctly predict the trend of adsorption enthalpy values, in terms of different gas molecules and Cs+ cation densities in the adsorbents, even though the absolute values of adsorption enthalpy are overestimated by approximate 10 kJ/mol compared with experiments.

  1. Chromatographic separation of inorganic ions on thin layers of titanium phosphate ion-exchanger.

    Science.gov (United States)

    Ghoulipour, Vanik; Safari, Moharram

    2014-12-01

    The chromatographic behavior of 30 inorganic cations has been studied on thin layers of titanium phosphate ion-exchanger using several aqueous, organic and mixed mobile phases. The separation of one ion from several other ions and also ternary and binary separations have been developed. Some important analytical separations are reported. The effect of pH of the mobile phase on retention factor (Rf) values of the cations in the presence of complex-forming anion along with the separation power of the ion-exchanger were studied. This ion-exchanger exhibits high sorption capacity and varying selectivity towards metal ions and makes it a suitable stationaiy phase in thin layer chromatography.

  2. Chromatographic separation of inorganic ions on thin layers of titanium phosphate ion-exchanger

    Institute of Scientific and Technical Information of China (English)

    Vanik GHOULIPOUR; Moharram SAFARI

    2014-01-01

    The chromatographic behavior of 30 inorganic cations has been studied on thin layers of titanium phosphate ion-exchanger using several aqueous,organic and mixed mobile phases. The separation of one ion from several other ions and also ternary and binary separations have been developed. Some important analytical separations are reported. The effect of pH of the mobile phase on retention factor(Rf)values of the cations in the presence of complex-forming anion along with the separation power of the ion-exchanger were studied. This ion-exchanger exhibits high sorption capacity and varying selectivity towards metal ions and makes it a suitable stationary phase in thin layer chromatography.

  3. Ultrafiltration Membrane Fouling and the Effect of Ion Exchange Resins

    KAUST Repository

    Jamaly, Sanaa

    2011-12-01

    Membrane fouling is a challenging process for the ultrafiltration membrane during wastewater treatment. This research paper determines the organic character of foulants of different kinds of wastewater before and after adding some ion exchange resins. Two advanced organic characterization methods are compared in terms of concentration of dissolved organic carbons: The liquid chromatography with organic carbon (LC-OCD) and Shimadzu total organic carbon (TOC). In this study, two secondary wastewater effluents were treated using ultrafiltration membrane. To reduce fouling, pretreatment using some adsorbents were used in the study. Six ion exchange resins out of twenty were chosen to compare the effect of adsorbents on fouling membrane. Based on the percent of dissolved organic carbon’s removal, three adsorbents were determined to be the most efficient (DOWEX Marathon 11 anion exchange resin, DOWEX Optipore SD2 polymeric adsorbent, and DOWEX PSR2 anion exchange), and three other ones were determined to the least efficient (DOWEX Marathon A2 anion exchange resin, DOWEX SAR anion exchange resin, and DOWEX Optipore L493 polymeric adsorbent). Organic characterization for feed, permeate, and backwash samples were tested using LC-OCD and TOC to better understand the characteristics of foulants to prevent ultrafiltration membrane fouling. The results suggested that the polymeric ion exchange resin, DOWEX SD2, reduced fouling potential for both treated wastewaters. All the six ion exchange resins removed more humic fraction than other organic fractions in different percent, so this fraction is not the main for cause for UF membrane fouling. The fouling of colloids was tested before and after adding calcium. There is a severe fouling after adding Ca2+ to effluent colloids.

  4. Rupture loop annex ion exchange RLAIX vault deactivation

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Ion-exchanged Tm3+:glass channel waveguide laser.

    Science.gov (United States)

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

    2013-04-01

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

  6. Microcrystalline hexagonal tungsten bronze. 1. Basis of ion exchange selectivity for cesium and strontium.

    Science.gov (United States)

    Griffith, Christopher S; Luca, Vittorio; Hanna, John V; Pike, Kevin J; Smith, Mark E; Thorogood, Gordon S

    2009-07-06

    The structural basis of selectivity for cesium and strontium of microcrystalline hexagonal tungsten bronze (HTB) phase Na(x)WO(3+x/2).zH(2)O has been studied using X-ray and neutron diffraction techniques, 1D and 2D (23)Na magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and radiochemical ion exchange investigations. For the HTB system, this study has shown that scattering techniques alone provide an incomplete description of the disorder and rapid exchange of water (with tunnel cations) occurring in this system. However, 1D and 2D (23)Na MAS NMR has identified three sodium species within the HTB tunnels-species A, which is located at the center of the hexagonal window and is devoid of coordinated water, and species B and C, which are the di- and monohydrated variants, respectively, of species A. Although species B accords with the traditional crystallographic model of the HTB phase, this work is the first to propose and identify the anhydrous species A and monohydrate species C. The population (total) of species B and C decreases in comparison to that of species A with increasing exchange of either cesium or strontium; that is, species B and C appear more exchangeable than species A. Moreover, a significant proportion of tunnel water is redistributed by these cations. Multiple ion exchange investigations with radiotracers (137)Cs and (85)Sr have shown that for strontium there is a definite advantage in ensuring that any easily exchanged sodium is removed from the HTB tunnels prior to exchange. The decrease in selectivity (wrt cesium) is most probably due to the slightly smaller effective size of Sr(2+); namely, it is less of a good fit for the hexagonal window, ion exchange site. The selectivity of the HTB framework for cesium has been shown unequivocally to be defined by the structure of the hexagonal window, ion exchange site. Compromising the geometry of this window even in the slightest way by either (1) varying the cell volume through

  7. Ion Exchange Kinetics Testing with SRF Resin

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-04-01

    The U.S. Department of Energy (DOE) Hanford Site contains more than 53 million gallons of legacy waste generated as a byproduct of plutonium production and reprocessing operations. The wastes are a complex mixture composed mostly of NaNO3, NaNO2, NaOH, NaAlO2, Na3PO4, and Na2SO4, with a number of minor and trace metals, organics, and radionuclides stored in underground waste tanks. The DOE Office of River Protection (ORP) has contracted Bechtel National Incorporated (BNI) to build a pretreatment facility, the River Protection Project-Waste Treatment Plant (RPP-WTP), that will separate long-lived transuranics (TRU) and highly radioactive components (specifically 137Cs and, in selected cases, 90Sr) from the bulk (non-radioactive) constituents and immobilize the wastes by vitrification. The plant is designed to produce two waste streams: a high-volume low-activity waste (LAW) and a low-volume high-activity waste (HLW).

  8. A novel silica based click lysine anion exchanger for ion exchange chromatography.

    Science.gov (United States)

    Guo, Hongyue; Chu, Changhu; Li, Yan; Yang, Bingcheng; Liang, Xinmiao

    2011-12-21

    Ion chromatography (IC) is one of the most powerful analysis technologies for the determination of charged compounds. A novel click lysine stationary phase was prepared via Cu(I) catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC) and applied to the analysis of inorganic ions. The chromatographic evaluation demonstrated good performance (e.g. the plate number of thiocyanate is ∼50,000 plates m(-1)) and effective separation ability for the common inorganic anions with aqueous Na(2)SO(4) eluent. The separation mechanism was observed to be mainly dominated by ion exchange interaction. The retention of these analytes is highly dependent on the pH value of eluent. Compared with the lysine stationary phase prepared via the conventional manner, the click lysine exchanger demonstrated shorter retention time and better ion separation characteristics under the same chromatographic conditions, which is a great advantage for rapid separation and analysis of inorganic ions.

  9. Spin-Exchange Collisions of the Ground State of Cs Atoms in a High Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    FU Li-Ping; LUO Jun; ZENG Xi-Zhi

    2000-01-01

    Cs atoms were optically pumped with a Ti:sapphire laser in a magnetic field of 1.516 T. Steady absorption spectra and populations of Zeeman sublevels of the ground state of Cs in N2 gas at various pressures (5, 40, and 80 Torr)were obtained. The results show that in a high magnetic field, the combined electron-nuclear spin transition(flip-flop transition), which is mainly induced by the collision modification δa( J.I)of hyperfine interaction, is an important relaxation mechanism at high buffer-gas pressures.

  10. Carbonate and Bicarbonate Ion Transport in Alkaline Anion Exchange Membranes

    Science.gov (United States)

    2013-06-25

    Bicarbonate Ion Transport in Alk Block 13: Supplementary Note © 2013 . Published in Journal of the Electrochemical Society , Vol. Ed. 0 160, (9) (2013...for public release; distribution is unlimited. ... 60325.7-CH-II F994 Journal of The Electrochemical Society , 160 (9) F994-F999 (2013) 0013-4651/2013...160(9)/F994/6/$31.00 © The Electrochemical Society Carbonate and Bicarbonate Ion Transport in Alkaline Anion Exchange Membranes Andrew M. Kiss,a

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

    KAUST Repository

    Geise, Geoffrey M.

    2014-08-26

    © the Partner Organisations 2014. Membrane potential and permselectivity are critical parameters for a variety of electrochemically-driven separation and energy technologies. An electric potential is developed when a membrane separates electrolyte solutions of different concentrations, and a permselective membrane allows specific species to be transported while restricting the passage of other species. Ion exchange membranes are commonly used in applications that require advanced ionic electrolytes and span technologies such as alkaline batteries to ammonium bicarbonate reverse electrodialysis, but membranes are often only characterized in sodium chloride solutions. Our goal in this work was to better understand membrane behaviour in aqueous ammonium bicarbonate, which is of interest for closed-loop energy generation processes. Here we characterized the permselectivity of four commercial ion exchange membranes in aqueous solutions of sodium chloride, ammonium chloride, sodium bicarbonate, and ammonium bicarbonate. This stepwise approach, using four different ions in aqueous solution, was used to better understand how these specific ions affect ion transport in ion exchange membranes. Characterization of cation and anion exchange membrane permselectivity, using these ions, is discussed from the perspective of the difference in the physical chemistry of the hydrated ions, along with an accompanying re-derivation and examination of the basic equations that describe membrane potential. In general, permselectivity was highest in sodium chloride and lowest in ammonium bicarbonate solutions, and the nature of both the counter- and co-ions appeared to influence measured permselectivity. The counter-ion type influences the binding affinity between counter-ions and polymer fixed charge groups, and higher binding affinity between fixed charge sites and counter-ions within the membrane decreases the effective membrane charge density. As a result permselectivity decreases. The

  12. Preparation of a Cation Exchanger from Cork Waste: Thermodynamic Study of the Ion Exchange Processes

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An ion exchanger was prepared by sulfonation of cork-waste chars. The exchange properties of the resultant materialwere characterized using Na+, Ca2+ or Fe3+ aqueous solutions, The content of metal ions in the solutions weredetermined by atomic absorption spectrometry. On the basis of the results obtained, the chemical equilibrium andits thermodynamic aspects related to the ion exchange process were studied. It was found that equilibrium constantK varies by the order: Na+<Ca2+<Fe3+, its value increasing with increasing temperature, and that △H°>0 and△S°>0, with -△G° following the sequence: Ca2+>Na+>Fe3+,

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

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.D.

    1999-01-15

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

  14. Synthesis, characterization and ion exchange properties of zirconium(IV) tungstoiodophosphate, a new cation exchanger

    Indian Academy of Sciences (India)

    Weqar Ahmad Siddiqui; Shakeel Ahmad Khan

    2007-02-01

    Zirconium(IV) tungstoiodophosphate has been synthesized under a variety of conditions. The most chemically and thermally stable sample is prepared by adding a mixture of aqueous solutions of 0.5 mol L-1 sodium tungstate, potassium iodate and 1 mol L-1 orthophosphoric acid to aqueous solution of 0.1 mol L-1 zirconium(IV) oxychloride. Its ion exchange capacity for Na+ and K+ was found to be 2.20 and 2.35 meq g-1 dry exchanger, respectively. The material has been characterized on the basis of chemical composition, pH titration, Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis. The effect on the exchange capacity of drying the exchanger at different temperatures has been studied. The analytical importance of the material has been established by quantitative separation of Pb2+ from other metal ions.

  15. Removal of Radioactive Nuclides by Multi-Functional Microcapsules Enclosing Inorganic Ion-Exchangers and Organic Extractants

    Energy Technology Data Exchange (ETDEWEB)

    Mimura, H.; Akiba, K.; Onodera, Y.

    2002-02-26

    The microcapsules enclosing two kinds of functional materials, inorganic ion-exchangers and organic extractants, were prepared by taking advantage of the high immobilization ability of alginate gel polymer. The fine powders of inorganic ion-exchanger and oil drops of extractant were kneaded with sodium alginate (NaALG) solution and the kneaded sol readily gelled in a salt solution of CaCl2, BaCl2 or HCl to form spherical gel particles. The uptake properties of various nuclides, 137Cs, 85Sr, 60Co, 88Y, 152Eu and 241Am, for thirty-four specimens of microcapsules in the presence of 10-1-10-4 M HNO3 were evaluated by the batch method. The distribution coefficient (Kd) of Cs+ above 103 cm3/g was obtained for the microcapsules enclosing CuFC or AMP. The Kd of Sr2+ around 102 cm3/g was obtained for the microcapsules containing clinoptilolite, antimonic acid, zeolite A, zeolite X or titanic acid. The microcapsules enclosing DEHPA exhibited relatively large Kd values of trivalent metal ions above 103 cm3/g; for example, the Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ for a favorable microcapsule (CuFC/clinoptilolite/DEHPA/CaALG) were 1.1x104, 7.5x10, 1.1x10, 1.0x104, 1.4x104, 3.4x103 cm3/g, respectively. The uptake rates of Cs+, Y3+, Eu3+ and Am3+ for this microcapsule were rather fast; the uptake percentage above 90% was obtained after 19 h-shaking and the uptake equilibrium was attained within 1 d. The AMP/CaALG exhibited high uptake ability for Cs+ even after irradiation of 188 kGy, and DEHPA/CaALG microcapsule had similar Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ ions before and after irradiation. The microcapsules with various shapes such as spherical, columnar, fibrous and filmy forms were easily prepared by changing the way of dipping kneaded sol into gelling salt solution. The microcapsules enclosing inorganic ion-exchangers and extractants have a potential possibility for the simultaneous removal of various radioactive nuclides from waste solutions.

  16. Stydy on the Model of Ion Exchange Kinetics

    Institute of Scientific and Technical Information of China (English)

    ChenFengrong; JiangZhixin

    1994-01-01

    In this paper, a macrokinetics model equation describing the characteristics of the solid-liquid mass transfer has been proposed.The qualitative analysis and experimental verification have been done for this mode equation.The model equation can explain the ion exchange process considerably well.

  17. Ion exchange membranes in seawater applications : processes and characteristics

    NARCIS (Netherlands)

    Galama, A.H.

    2015-01-01

    Officiële titel ENG: Ion exchange membranes in seawater applications. Processes and characteristics Officiële titel NL: Ionwisselende membranen in zeewatertoepassingen. Processen en eigenschappen Auteur: A.H.Galama Jaar: 2015 ISBN: 978-94-6257-225-6 Samenvatting Zeewaterontzouting stelt me

  18. EVALUATING ION EXCHANGE FOR REMOVING RADIUM FROM GROUNDWATER

    Science.gov (United States)

    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...

  19. Determination of boron in silicates after ion exchange separation

    Science.gov (United States)

    Kramer, H.

    1955-01-01

    Existing methods for the determination of boron in silicates are not entirely satisfactory. Separation as the methyl ester is lengthy and frequently erratic. An accurate and rapid method applicable to glass, mineral, ore, and water samples uses ion exchange to remove interfering cations, and boron is determined titrimetrically in the presence of mannitol, using a pH meter to indicate the end point.

  20. Thermal Analysis for Ion-Exchange Column System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Si Y.; King, William D.

    2012-12-20

    Models have been developed to simulate the thermal characteristics of crystalline silicotitanate ion exchange media fully loaded with radioactive cesium either in a column configuration or distributed within a waste storage tank. This work was conducted to support the design and operation of a waste treatment process focused on treating dissolved, high-sodium salt waste solutions for the removal of specific radionuclides. The ion exchange column will be installed inside a high level waste storage tank at the Savannah River Site. After cesium loading, the ion exchange media may be transferred to the waste tank floor for interim storage. Models were used to predict temperature profiles in these areas of the system where the cesium-loaded media is expected to lead to localized regions of elevated temperature due to radiolytic decay. Normal operating conditions and accident scenarios (including loss of solution flow, inadvertent drainage, and loss of active cooling) were evaluated for the ion exchange column using bounding conditions to establish the design safety basis. The modeling results demonstrate that the baseline design using one central and four outer cooling tubes provides a highly efficient cooling mechanism for reducing the maximum column temperature. In-tank modeling results revealed that an idealized hemispherical mound shape leads to the highest tank floor temperatures. In contrast, even large volumes of CST distributed in a flat layer with a cylindrical shape do not result in significant floor heating.

  1. A new hybrid ion exchanger: Effect of system parameters on the adsorption of vanadium (V)

    Energy Technology Data Exchange (ETDEWEB)

    Yeom, Bong-Yeol [Nonwovens Cooperative Research Center, College of Textiles, North Carolina State University, Raleigh, NC 27695-8301 (United States); Lee, Chang-Soo [School of Applied Chemistry and Biological Engineering, College of Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Hwang, Taek-Sung, E-mail: tshwang@cnu.ac.kr [School of Applied Chemistry and Biological Engineering, College of Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2009-07-15

    The hybrid ion exchanger consisted of PONF-g-GMA anion fibrous exchanger and IRA-96 bead-type anion exchanger was developed by combining different types of layers with hot-melt adhesive. Its ion exchange capacity and the pressure drop with flow rate of water were measured and the adsorption of vanadium (V) ions on the hybrid ion exchanger was evaluated with various process parameters such as pH, initial concentration, and temperature. It was observed that the adsorption kinetics of vanadium (V) ions on the hybrid ion exchanger could be analyzed with pseudo-second-order model.

  2. New fluorescence results of Fe^3+ ions in Cs_2NaScF_6

    Science.gov (United States)

    Sosman, L. P.; da Fonseca, R. J. M.; Dias Tavaves, A., Jr.; Bordallo, H. N.; Khaidukov, N. M.

    2002-03-01

    Many spectroscopic studies on oxide materials doped with trivalent iron ions have been reported in the literature [1-4]. However, investigation on Fe3^+ luminescence in fluoride hosts is comparatively rare at the moment. In this work we present the initial fluorescence results for Cs_2NaGaF_6:Fe3^+. The emission spectrum at room temperature exhibits a broad emission band with maximum intensity at 800 nm. We believe that this emission is associated with substitutional occupancy of the octahedral Ga3^+ sites by iron ions. We also observe a band at 600 nm that corresponds probably to defect centers. [1] O´Connor G, McDonagh C, Glynn T J, 1991 J Luminescence 48 & 49 545 [2] Walker G, Glynn T J 1992 J Luminescence 54 131 [3] Kutty T R N, Nayak M, 1998 Journal of Alloys and Compounds 269 75 [4] Sosman L P, Dias Tavares Jr. A, Silva P S, Abritta T 1999 176 1085

  3. CsI-silicon heavy-ion telescope for storage rings

    Energy Technology Data Exchange (ETDEWEB)

    Najafi, Mohammad Ali [TU Muenchen (Germany); JLU Giessen (Germany); Dillmann, Iris [GSI Darmstadt (Germany); TRIUMF, Vancouver (Canada); JLU Giessen (Germany); Bosch, Fritz; Gao, Bingshui; Kozhuharov, Christophor; Litvinov, Sergey A.; Litvinov, Yuri A.; Nolden, Fritz; Popp, Ulrich; Sanjari, Mohammad Shahab; Spillmann, Uwe; Steck, Markus; Stoehlker, Thomas; Weick, Helmut [GSI Darmstadt (Germany); Boehmer, Michael; Faestermann, Thomas; Gernhaeuser, Roman; Maier, Ludwig [TU Muenchen (Germany)

    2015-07-01

    A multi-purpose particle detector was developed for heavy-ion experiments at the ESR in GSI Darmstadt, and also as a prototype for future ILIMA and EXL experiments at FAIR. The detector was designed and developed at the TU Muenchen, and was used successfully for the measurement of the decay rate of {sup 142}Pm ions in October 2014. The detector has an active area of 60 x 40 mm{sup 2} and includes a stack of six silicon pad detectors, a DSSD, and a CsI scintillator (24 x 24 x 10 mm{sup 3}) that stops the beam after a passive degrader. The excellent resolution of the detector allows an unambiguous identification of the incident particles. The relative resolution (FWHM) of the detector is 1% for the energy deposit (ΔE), and 0.9% for the residue energy (E{sub csi}), and 0.8% for the total summed energy. We report on the design, development, and the preliminary results from the experiment.

  4. Photowritten gratings in ion-exchanged glass waveguides.

    Science.gov (United States)

    Roman, J E; Winick, K A

    1993-05-15

    The fabrication of an ion-exchanged waveguide beam deflector containing a photowritten grating is described. The planar waveguide was fabricated by thermal K(+) exchange in a borosilicate glass. The grating was written by photobleaching an absorption defect centered at 330 am, which was created by gamma-ray irradiation of the glass. The bleaching was accomplished with the 351-nm line from an argon laser. The device achieved 35% deflection efficiency at 633 nm, which corresponded to a grating with a photoinduced index change of 2.6 x 10(-5). This is to our knowledge the first demonstration of an ion-exchanged glass waveguide device containing a permanent photowritten grating.

  5. Controlled charge exchange between alkaline earth metals and their ions

    Science.gov (United States)

    Gacesa, Marko; Côté, Robin

    2015-05-01

    We theoretically investigate the prospects of realizing controlled charge exchange via magnetic Feshbach resonances in cold and ultracold collisions of atoms and ions. In particular, we focus on near-resonant charge exchange in heteroisotopic combinations of alkaline earth metals, such as 9Be++10 Be9 Be+10Be+ , which exhibit favorable electronic and hyperfine structure. The quantum scattering calculations are performed for a range of initial states and experimentally attainable magnetic fields in standard coupled-channel Feshbach projection formalism, where higher-order corrections such as the mass-polarization term are explicitely included. In addition, we predict a number of magnetic Feshbach resonances for different heteronuclear isotopic combinations of the listed and related alkaline earth elements. Our results imply that near-resonant charge-exchange could be used to realize atom-ion quantum gates, as well as controlled charge transfer in optically trapped cold quantum gases. This work is partially supported by ARO.

  6. Systematics of heavy-ion charge-exchange straggling

    Science.gov (United States)

    Sigmund, P.; Schinner, A.

    2016-10-01

    The dependence of heavy-ion charge-exchange straggling on the beam energy has been studied theoretically for several ion-target combinations. Our previous work addressed ions up to krypton, while the present study focuses on heavier ions, especially uranium. Particular attention has been paid to a multiple-peak structure which has been predicted theoretically in our previous work. For high-Z1 and high-Z2 systems, exemplified by U in Au, we identify three maxima in the energy dependence of charge-exchange straggling, while the overall magnitude is comparable with that of collisional straggling. Conversely, for U in C, charge-exchange straggling dominates, but only two peaks lie in the energy range where we presently are able to produce credible predictions. For U-Al we find good agreement with experiment in the energy range around the high-energy maximum. The position of the high-energy peak - which is related to processes in the projectile K shell - is found to scale as Z12 , in contrast to the semi-empirical Z13/2 dependence proposed by Yang et al. Measurements for heavy ions in heavy targets are suggested in order to reconcile a major discrepancy between the present calculations and the frequently-used formula by Yang et al.

  7. Separation of americium from curium by oxidation and ion exchange.

    Science.gov (United States)

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

    2012-08-21

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

  8. Using ion exchange chromatography to purify a recombinantly expressed protein.

    Science.gov (United States)

    Duong-Ly, Krisna C; Gabelli, Sandra B

    2014-01-01

    Ion exchange chromatography (IEX) separates molecules by their surface charge, a property that can vary vastly between different proteins. There are two types of IEX, cation exhange and anion exchange chromatography. The protocol that follows was designed by the authors for anion exchange chromatography of a recombinantly expressed protein having a pI of 4.9 and containing two cysteine residues and one tryptophan residue, using an FPLC system. Prior to anion exchange, the protein had been salted out using ammonium sulfate precipitation and partially purified via hydrophobic interaction chromatography (see Salting out of proteins using ammonium sulfate precipitation and Use and Application of Hydrophobic Interaction Chromatography for Protein Purification). Slight modifications to this protocol may be made to accommodate both the protein of interest and the availability of equipment.

  9. Studies on the solid-state ion exchange of nickel ions into zeolites using DRS technique

    Science.gov (United States)

    Zanjanchi, M. A.; Ebrahimian, A.

    2004-05-01

    The coordination of Ni 2+ ions in the dehydrated nickel-exchanged zeolites was investigated from the analysis of diffuse reflectance spectra. Solid-state ion exchange method was used to prepare nickel-containing mordenite, Y, L and mazzite zeolites. In the dehydrated mordenite and zeolite Y, nickel cations are presented in both forms of tetrahedral and distorted tetrahedral symmetries. The relative amount of tetrahedral and distorted tetrahedral nickel species are related to the heating temperature and heating time used for calcinations. In the dehydrated zeolite L and mazzite, Ni 2+ ions are mainly in the distorted octahedral symmetries.

  10. Radiolytic stability of some recently developed ion exchange and extraction chromatographic resins containing diphosphonic acid groups

    Energy Technology Data Exchange (ETDEWEB)

    Chiarizia, R.; Horwitz, E.P.

    2000-01-01

    The effect of {sup 60}Co irradiation on the Diphonix{trademark}, Diphosil and Diphonix-CS chelating ion exchange resins, and on two Dipex{trademark} extraction chromatographic resins containing the P,P{prime}-di(2-ethylhexyl) methanediphosphonic acid (H{sub 2}DEH[MDP]) impregnated in the pores of a polymeric support (Dipex-1) and of silica (Dipex-2), respectively, has been investigated. The resins have been irradiated while in contact with HNO{sub 3} (Diphonix, Diphosil and Dipex resins) or NaOH (Diphonix-DS resin) up to an absorbed dose of about 200 Mrad. As a probe of the resin radiolytic degradation, metal uptake (both equilibrium and kinetics) and capacity measurements have been performed. Results show that the Diphonix-CS resin properties are practically unaffected by irradiation under the experimental conditions used in this work. The Diphonix, Diphosil, and especially the Dipex resins suffer substantial capacity losses, but their affinity for actinide ions is not seriously compromised. On the other hand, the kinetics of metal uptake by the silica based Diphosil and Dipex-2 resins becomes substantially slower indicating that, from a radiolytic degradation standpoint, polymeric materials perform better than silica as supports for H{sub 2}DEH[MDP] containing extraction chromatographic resins.

  11. Separation of seven arsenic species by ion-pair and ion-exchange high performance liquid chromatography

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Hansen, Sven Hedegaard

    1992-01-01

    Arsenite, arsenate, monomethylarsonate, dimethylarsinate, arsenobetaine, arsenocholine and the tetramethylarsonium ion were subjected to ion-exchange and ion-pair reversed phase HPLC. The ion exchange method was superior in selectivity and time of analysis for the arsenic anions. The ammonium ions...... used for the ion-pair method only resulted in separation of some of the anionic arsenic compounds. Flame atomic absorption spectrometry was used for on-line arsenic-specific detection....

  12. On-line ion chemistry for the AMS analysis of {sup 90}Sr and {sup 135,137}Cs

    Energy Technology Data Exchange (ETDEWEB)

    Eliades, J. [IsoTrace Laboratory, University of Toronto, 60 St. George St., Toronto, ON, M5S 1A7 (Canada); Zhao, X.-L. [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, ON, K1N 6N5 (Canada); Litherland, A.E. [IsoTrace Laboratory, University of Toronto, 60 St. George St., Toronto, ON, M5S 1A7 (Canada); Kieser, W.E., E-mail: liam.kieser@utoronto.ca [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, ON, K1N 6N5 (Canada)

    2013-01-15

    The analysis of {sup 90}Sr by AMS has so far required the use of very large tandem accelerators in order to separate the isobar {sup 90}Zr by the rate-of-energy-loss method. The analysis of {sup 135,137}Cs by AMS has never been attempted as the separation of the isobars {sup 135,137}Ba by the traditional method requires even higher energies, so that this approach would become prohibitively expensive for routine analysis. Following the successful demonstration of Cl{sup -}-S{sup -} separation by the Isobar Separator, the same apparatus was used to test the separation of other pairs of isobars. Surprisingly effective results were obtained with NO{sub 2} gas in the cases of SrF{sub 3}{sup -}-ZrF{sub 3}{sup -} and CsF{sub 2}{sup -}-BaF{sub 2}{sup -} separations. Reduction factors of {approx}4 Multiplication-Sign 10{sup -6} for ZrF{sub 3}{sup -}/SrF{sub 3}{sup -} and {approx}2 Multiplication-Sign 10{sup -5} for BaF{sub 2}{sup -}/CsF{sub 2}{sup -} were measured. SrF{sub 3}{sup -} and CsF{sub 2}{sup -} are both super-halogen anions and are preferentially produced in the ion source rather than ZrF{sub 3}{sup -} and BaF{sub 2}{sup -} when using the PbF{sub 2} matrix-assisted method. Reduction factors for ion source production with such targets of {approx}3 Multiplication-Sign 10{sup -5} for ZrF{sub 3}{sup -}-SrF{sub 3}{sup -} and {approx}5 Multiplication-Sign 10{sup -4} for BaF{sub 2}{sup -}-CsF{sub 2}{sup -} were found. The combined methods would suggest a theoretical detection sensitivity for {sup 90}Sr/Sr {approx}6 Multiplication-Sign 10{sup -16}, {sup 135}Cs/Cs {approx}7 Multiplication-Sign 10{sup -15} and {sup 137}Cs/Cs {approx}1 Multiplication-Sign 10{sup -14}, assuming 10 ppm Zr and Ba contamination in the AMS targets. In addition to the earlier Cl{sup -}-S{sup -} separation work, these measurements further illustrate the potential of on-line ion chemical methods for broadening the analytical scope of small AMS systems.

  13. Grafted megaporous materials as ion-exchangers for bioproduct adsorption.

    Science.gov (United States)

    Bibi, Noor Shad; Fernández-Lahore, Marcelo

    2013-01-01

    Megaporous chromatographic materials were manufactured by a three-step procedure, including backbone synthesis, chemical grafting, and introduction of ion-exchange functionality. The backbone of the adsorbent cylindrical bodies was prepared by polymerization of methacrylic acid and poly(ethylene glycol) diacrylate at sub-zero temperatures. Grafting was performed employing glycidyl methacrylate and a chemical initiator, cerium ammonium nitrate. The degree of grafting was adjusted by modifying the concentration of the initiator in the reaction mixture to a range of values (23, 39, 62, 89, and 105%). Further, the pendant epoxy-groups generated by the previous step were reacted to cation- and anion-exchanging moieties utilizing known chemical routes. Infrared spectroscopy studies confirmed the incorporation of epoxy and ion-exchanger groups to the backbone material. Optimized materials were tested for chromatography applications with model proteins; the dynamic binding capacity, as recorded at 10% breakthrough and 2.0 × 10(-4) m/s superficial velocity, were 350 and 58 mg/g for the cation-exchanger and the anion-exchanger material, respectively. These results may indicate that long tentacle-type polymer brushes were formed during grafting therefore increasing the ability of the megaporous body to efficiently capture macromolecules.

  14. Charge Exchange Effect on Space-Charge-Limited Current Densities in Ion Diode

    Institute of Scientific and Technical Information of China (English)

    石磊

    2002-01-01

    The article theoretically studied the charge-exchange effects on space charge limited electron and ion current densities of non-relativistic one-dimensional slab ion diode, and compared with those of without charge exchange.

  15. Chemical and radiation stability of a proprietary cesium ion exchange material manufactured from WWL membrane and SuperLig{reg_sign} 644

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.N.; Carson, K.J.; DesChane, J.R.; Elovich, R.J.; Berry, P.K.

    1996-09-01

    Pretreatment of nuclear process wastes for ion exchange removal of Cs and other radionuclides is one way to minimize amount of high-level radioactive waste at Hanford. This study evaluated Cs-selective SuperLig{reg_sign}644 (IBC Advanced Technologies, American Fork UT) entrapped in a proprietary WWL web membrane (3M) for chemical/radiation stability in simulated caustic neutralized current acid waste (NCAW), 0.5M HNO{sub 3}, water, and air. After exposure up to 2.0E+09 rad, the material was evaluated for Cs uptake in 5M sodium NCAW simulants with varying Cs contents. Radiolytic stability appears to be sufficient for ion exchange pretreatment of radioactive Cs: essentially no decrease in Cs selectivity or loading (Kd) was observed during {sup 60}Cs gamma irradiation in water or 0.5M HNO{sub 3} up to 1.0E+09 rad. Cs Kd decreased by a factor of 2 after 2.0E+09 rad exposure. Cs Kd did not change during irradiation in 5M NCAW or ambient air up to 1.0E+08 rad, but decreased by more than an order of magnitude between 1.0E+08 and 2.0E+09 rad (not typical of process conditions). Chemical stability under caustic conditions is lower than in air or under neutral/acidic conditions. Results indicate that this material is less stable in caustic solution irrespective of radiation exposure. Samples of the membrane retained their physical form throughout the entire experiment and were only slightly brittle after exposure to 2.0E+09 rad. (The material evaluated was a finely ground (400 mesh) particulate engineered to form a polymeric fiber (WWL), not the macroscopic form of SuperLig{reg_sign} 644 resin (20 to 50 mesh).)

  16. Ion exchange at the critical point of solution.

    Science.gov (United States)

    Savoy, J D; Baird, J K; Lang, J R

    2016-03-11

    A mixture of isobutyric acid (IBA)+water has an upper critical point of solution at 26.7°C and an IBA concentration of 4.40M. We have determined the Langmuir isotherms for the hydroxide form of Amberlite IRN-78 resin in contact with mixtures of IBA+water at temperatures, 27.0, 29.0, 31.0 and 38.0°C, respectively. The Langmuir plot at 38.0°C forms a straight line. At the three lower temperatures, however, a peak in the Langmuir plot is observed for IBA concentrations in the vicinity of 4.40M. We regard this peak to be a critical effect not only because it is located close to 4.40M, but also because its height becomes more pronounced as the temperature of the isotherm approaches the critical temperature. For concentrations in the vicinity of the peak, the data indicate that the larger isobutyrate ion is rejected by the resin in favor of the smaller hydroxide ion. This reversal of the expected ion exchange reaction might be used to separate ions according to size. Using the Donnan theory of ion exchange equilibrium, we link the swelling pressure to the osmotic pressure. We show that the peak in the Langmuir plot is associated with a maximum in the "osmotic" energy. This maximum has its origin in the concentration derivative of the osmotic pressure, which goes to zero as the critical point is approached.

  17. Thermal annealing of K(+)-Na(+) ion-exchanged waveguides.

    Science.gov (United States)

    Giorgetti, E; Grando, D; Palchetti, L; Sottini, S

    1995-06-15

    The process of thermal annealing of K(+)(-)Na(+) ion-exchanged waveguides in soda lime glass is characterized and compared with a simple theoretical model. The discrepancies between theory and experiments in the case of initially thick guides disappear if the existence of a stress-induced contribution to the refractive index is assumed that is not proportional to the concentration of the doping ions. The results obtained for initially thin guides are exploited for the design of annealed single-mode channel waveguides: 0.4-dB coupling losses with commercial single-mode fibers at lambda = 1.321 microm were measured.

  18. Optimization of ion exchange in polishers at PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Miller, A.D. [Pedro Point Technology, Inc., Pacifica, CA (United States); Fruzzetti, K. [Electric Power Research Inst., Palo Alto, CA (United States)

    2004-08-01

    Blowdown polishers are indispensable components in the secondary systems of pressurized water reactors. The application of advanced amines to reduce iron levels in final steam generator feedwater influences the resin selection for and operation of condensate polishers. There are many opportunities to optimize blowdown polisher performance. This paper summarizes the work currently underway to optimally use resin properties such as ion selectivity and capacity and operational parameters to maximize water quality while minimizing cost. It is shown that the best amine for a given power plant is a complex function of amine properties, ion exchange resin choice, purification systems and other plant design and operational parameters. (orig.)

  19. IR Spectroscopic Study of Adsorption of Binary Gases over Ion-Exchanged ZSM-5 Zeolites.

    Science.gov (United States)

    Katoh; Yamazaki; Ozawa

    1998-07-15

    Adsorption of binary gases (CH4/CO, CO/NO, and CO/CO2) on alkali metal (Li, Na, K, Rb, and Cs) ion-exchanged ZSM-5 zeolites were studied using IR spectroscopy. IR absorption bands of preadsorbed CH4, particularly that of nu1 (induced band), decreased with the increase in the partial pressure of CO, indicating the preferential adsorption of CO on the cation site of zeolite. In addition, IR band profiles of adsorbed CO changed in a different manner when CH4, NO, or CO2 was added to the system, suggesting that the selectivity of adsorption was governed not only by the polarity of adsorbates but also by the nature of sites present in the ZSM-5 pore bearing different electric field strengths. Copyright 1998 Academic Press.

  20. Diffusion kinetics of the ion exchange of benzocaine on sulfocationites

    Science.gov (United States)

    Al'tshuler, O. G.; Shkurenko, G. Yu.; Gorlov, A. A.; Al'tshuler, G. N.

    2016-06-01

    The theory of the ion exchange kinetics on strong acid cationites with the participation of weak electrolytes is discussed. The kinetics of desorption of benzocaine in the protonated and molecular forms from strong acid cationites, sulfonated polycalixarene, and KU-23 30/100 sulfocationite, is studied experimentally. It is shown that the flow of protonated benzocaine from cationite upon desorption proceeding by the ion-exchange mechanism is more intense than upon desorption of nonionized benzocaine molecules. It is established that the diffusion coefficient of benzocaine cations is (1.21 ± 0.23) × 10-12 m2/s in KU-23 30/100 sulfocation and (0.65 ± 0.06) × 10-13 m2/s in sulfonated polycalixarene, while the diffusion coefficient of benzocaine molecules is (0.65 ± 0.15) × 10-14 m2/s in sulfonated polycalixarene.

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

    Science.gov (United States)

    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.

  2. Determination of ammonium ion in biological nitrification-denitrification process water by ion exclusion chromatography with ion exchange enhancement of conductivity detection.

    OpenAIRE

    田中, 一彦; 黒川, 利一; 中島, 良三; Fritz, James S.

    1988-01-01

    Ammonium ion in biological nitrification-denitrification process with batchwise treatment was determined by ion exclusion chromatography using water as an eluent with ion exchange enhancement of conductivity. Ammonium ion was selectively separated by ion exclusion from alkali metal and alkaline earth metal cations. The detection sensitivity of the ammonium ion was improved about 11-fold with two ion exchange enhancement columns inserted in series between the separation column packed with OH--...

  3. An investigation into the electrochemical recovery of rare earth ions in a CsCl-based molten salt

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Shuqiang, E-mail: sjiao@ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083 (China); Zhu, Hongmin, E-mail: hzhu@metall.ustb.edu.cn [School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083 (China)

    2011-05-30

    A CsCl-based melt, was used as a supporting electrolyte for a fuel cycle in pyrochemical separation, as it has a high solubility for lanthanide oxide. Cyclic voltammetry and square wave voltammetry were carried out to investigate the cathodic reduction of those rare earth ions. The results prove that the cathodic process of La(III) ions dissolved in a CsCl-based melt, with a one-step reduction La{sup 3+} + 3e{sup -} = La, and is similar to those of other reports which have utilised LiCl-KCl or CaCl{sub 2}-KCl molten salt systems. However, for the Ce(III) ions that dissolved in a CsCl-based melt, there is a significant difference when compared with published literature as there are two reduction steps instead of the reported single step Ce{sup 3+} + e{sup -} = Ce{sup 2+} and Ce{sup 2+} + 2e{sup -} = Ce. In order to explain the novel result, a detailed investigation was focused on the cathodic process of Ce(III) in a CsCl-based melt. The identification of the M-O (M = La, Ce) compounds that are stable in the electrolyte, as well as the determination of their solubility products, were carried out by potentiometric titration using an oxide ion sensor. Furthermore, the E-pO{sup 2-} (potential-oxide ion) diagram for the M-O stable compound was constructed by combining both theoretical and experimental data.

  4. Separation of organic ion exchange resins from sludge -- engineering study

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, J.B.

    1998-08-25

    This engineering study evaluates the use of physical separation technologies to separate organic ion exchange resin from KE Basin sludge prior to nitric acid dissolution. This separation is necessitate to prevent nitration of the organics in the acid dissolver. The technologies under consideration are: screening, sedimentation, elutriation. The recommended approach is to first screen the Sludge and resin 300 microns then subject the 300 microns plus material to elutriation.

  5. Dimerisation of isobutene on acidic ion-exchange resins

    OpenAIRE

    Honkela, Maija

    2005-01-01

    Dimerisation of isobutene produces diisobutenes that can be hydrogenated to isooctane (2,2,4-trimethyl pentane). Isooctane can be used as a high octane gasoline component. The aim of this work was to study the selective production of diisobutenes through the dimerisation of isobutene on ion-exchange resin catalysts and to construct kinetic models for the reactions in the system for reactor design purposes. High selectivities for diisobutenes were obtained in the presence of polar componen...

  6. Quantitatively measured photorefractive sensitivity of proton-exchanged lithium niobate, proton-exchanged magnesium oxide-doped lithium niobate, and ion-exchanged potassium titanyl phosphate waveguides.

    Science.gov (United States)

    Kondo, Y; Miyaguchi, S; Onoe, A; Fujii, Y

    1994-06-01

    The photorefractive sensitivities of proton-exchanged lithium niobate waveguides and Rb-ion-exchanged potassium titanyl phosphate waveguides are quantitatively measured, and their influence on waveguide applications is estimated.

  7. Characterization of ion-exchange membrane materials: properties vs structure.

    Science.gov (United States)

    Berezina, N P; Kononenko, N A; Dyomina, O A; Gnusin, N P

    2008-06-22

    This review focuses on the preparation, structure and applications of ion-exchange membranes formed from various materials and exhibiting various functions (electrodialytic, perfluorinated sulphocation-exchange and novel laboratory-tested membranes). A number of experimental techniques for measuring electrotransport properties as well as the general procedure for membrane testing are also described. The review emphasizes the relationships between membrane structures, physical and chemical properties and mechanisms of electrochemical processes that occur in charged membrane materials. The water content in membranes is considered to be a key factor in the ion and water transfer and in polarization processes in electromembrane systems. We suggest the theoretical approach, which makes it possible to model and characterize the electrochemical properties of heterogeneous membranes using several transport-structural parameters. These parameters are extracted from the experimental dependences of specific electroconductivity and diffusion permeability on concentration. The review covers the most significant experimental and theoretical research on ion-exchange membranes that have been carried out in the Membrane Materials Laboratory of the Kuban State University. These results have been discussed at the conferences "Membrane Electrochemistry", Krasnodar, Russia for many years and were published mainly in Russian scientific sources.

  8. Raman microspectroscopy investigation of Ag ion-exchanged glass layers.

    Science.gov (United States)

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

    2012-11-01

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

  9. Ion exchange properties of titanic fiber of layered structure

    Energy Technology Data Exchange (ETDEWEB)

    Fujiki, Yoshinori; Komatsu, Yu; Sasaki, Takayoshi

    1986-12-01

    Usually, titanic acid is produced by hydrolyzing titanium tetrachloride, titanium sulfate or titanium alkoxide and is obtained in the form of precipitate in an amorphous gel state. The present authors have synthesized two types of titanic fibers of a layered crystaline structure to provide new ion exchangers. Three synthetic techniques, namely, flux process, annealing baking process and melt process, have been developed. This report deals with the structure and properties of these materials. In the flux process, a mixture of TiO/sub 2/, K/sub 2/CO/sub 3/ and K/sub 2/MoO/sub 4/ (flux) is melted at 1150 deg C and annealed at about 950 deg C to provide a K/sub 2/Ti/sub 4/O/sub 3/ fiber of a layered structure, which is subsequently converted into H/sub 2/Ti/sub 4/O/sub 9/ center dot nH/sub 2/O fiber. In the melt process, a mixture of materials is heate up to 1100 deg C to produce molten K/sub 2/Ti/sub 2/O/sub 5/, which is quenched to form K/sub 2/Ti/sub 2/O/sub 5/ fiber of a layered structure. Then it is converted into H/sub 2/Ti/sub 2/O/sub 5/ center dot nH/sub 2/O fiber. The annealing baking process provides K/sub 2/Ti/sub 4/O/sub 9/, which is converted into K/sub 2/Ti/sub 2/O/sub 5/ fiber. In this report, the crystal structure of H/sub 2/Ti/sub 4/O/sub 9/ center dot nH/sub 2/O is discussed and the ion exchanging properties are analized. Examination is made on the ion exchanging reactions involving potassium, alkali metal ions, alkaline earth metal ions and divalent transition metal ions. Various ion exchangers, including the present ones, are compared in terms of the partition coefficient and separation factor. (Nogami, K.).

  10. The state of Cs-137 in natural water solution

    Energy Technology Data Exchange (ETDEWEB)

    Toropova, V.V.; Toropov, I.G.; Davydov, Yu.P. [Institute of Radioecological, Minsk (Belarus); Efremenkov, V.M. [Institute of Power Engineering, Minsk (Belarus)

    1996-12-31

    The state of Cs radionuclides has been studied in natural water systems - waters of some rivers, water channel, marshes. Investigations were performed using methods of ultrafiltration, dialysis, ion exchange. Based on experimental results obtained conclusions were made on state of radiocaesium in natural waters. It was shown, that Cs in such solutions presents mainly in ionic form. It is shown, how Cs may change its dispersion conditions in natural waters.

  11. Atomistic insight into adsorption, mobility, and vibration of water in ion-exchanged zeolite-like metal-organic frameworks.

    Science.gov (United States)

    Nalaparaju, A; Babarao, R; Zhao, X S; Jiang, J W

    2009-09-22

    The adsorption, mobility, and vibration of water in ion-exchanged rho-zeolite-like metal-organic frameworks (ZMOFs) are investigated using atomistic simulations. Because of the high affinity for the ionic framework and nonframework ions, water is strongly adsorbed in rho-ZMOFs with a three-step adsorption mechanism. At low pressures, water is preferentially adsorbed onto Na(+) ions, particularly at site II; with increasing pressure, adsorption occurs near the framework and finally in the large cage. Upon water adsorption, Na(+) ions are observed to redistribute from site I to site II and gradually hydrated with increasing pressure. In Li-, Na-, and Cs-exchanged rho-ZMOFs, the adsorption capacity and isosteric heat decrease with increasing ionic radius attributed to the reduced electrostatic interaction and free volume. The mobility of water in Na-rho-ZMOF increases at low pressures but decreases upon approaching saturation. With sufficient amount of water present, the mobility of Na(+) ions is promoted. The vibrational spectra of water in Na-rho-ZMOF exhibit distinct bands for librational motion, bending, and stretching. The librational motion has a frequency higher than bulk water due to confinement. With increasing loading and hence stronger coordinative attraction, the bending frequency shows a blue shift. Symmetric and asymmetric modes are observed in the stretching as a consequence of the strong water-ion interaction. This study provides a fundamental microscopic insight into the static and dynamic properties of water in charged ZMOFs and reveals the subtle interplay between water and nonframework ions.

  12. STRUCTURAL FEATURE AND EXCHANGE KINETICS OF CARBOXYLATED POLYPROPYLENE ION EXCHANGE RESIN

    Institute of Scientific and Technical Information of China (English)

    WU Chinyung; YANG Chaoshiung; YANG Chong

    1987-01-01

    The present article deals with the exchange process of bivalent metal ions, such as Zn2 +, Cd2 + and Hg2+, etc., taken up by non-crosslinked carboxylated polypropylene (CPP) resin. The control factor of the exchange rate deduced from the kinetic data is governed basically by the chemical reaction rather than the mass transfer effect particle diffusion and/or liquid film diffusion. In solution, all the graft chains in the outer shell ofa CPP resin could form a "quasi-macromolecular solution" domain. This opinion further demonstrates the structural pattern of CPP resin proposed in earlier paper[1].

  13. Negative Joule Heating in Ion-Exchange Membranes

    CERN Document Server

    Biesheuvel, P M; Hamelers, H V M

    2014-01-01

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

  14. Hydrous Tantalum Phosphates for Ion Exchange Purposes: A Systematic Study

    Directory of Open Access Journals (Sweden)

    M.L.C.P.da Silva

    2002-03-01

    Full Text Available This work describes two methods of preparation of hydrous tantalum phosphates and their characterization as ion exchangers. The hydrous metallic phosphate compounds were chemically and physically characterized by thermal gravimetric analysis, X-ray diffractometry and surface area measurements. By the first method, tantalum phosphate was prepared by alkaline fusion of Ta2O5 with an excess of K2CO3, followed by lixiviation of the tantalate fusion product with hot water, and precipitation with diluted H3PO4. Preparation II was performed using metallic Ta dissolved in concentrated HF/HNO3 acidic mixture followed by hydrolysis of fluortantalic acid intermediary and precipitation with diluted H3PO4. Both freshly prepared materials (I and II were exaustively refluxed with concentrated H3PO4, in its boiling point temperature, resulting respectively in Ta2O5. 2.1 H2O, (IR and Ta2O5. 1.3 H2O, (IIR. Characterization of the prepared products have presented the following values: surface area of 108.27 ± 2.80; 220.14 ± 2.67; 117.07 ± 5.25 and 141.61 ± 0.27 m².g-1 respectively for I, IR, II and IIR. All these materials were amorphous. The ion exchange behavior for all four hydrous tantalum phosphates was studied using Na+, K+ and Ba+2 as the exchanged species. The values for typical ion exchange capacity were 1.64; 1.23; 1.47 and 1.01 miliequivalent.g-1, respectively for I, IR, II and IIR products.

  15. Binary ion exchange of metal ions in Y and X zeolites

    Directory of Open Access Journals (Sweden)

    M.A.S.D. Barros

    2003-10-01

    Full Text Available The ion exchange of Na for Cr/K, Cr/Mg and Cr/Ca in Y and X zeolites was studied using breakthrough curves. It was observed that Cr3+ ions were able to remove some competitive ions that had already been exchanged at the zeolitic sites, producing a sequential ion exchange. Some mass transfer parameters such as length of unused bed, overall mass transfer coefficient, operational ratio and dimensionless variance were studied. Chromium uptake was influenced much more by the competing ion in the NaX zeolite columns. The dimensionless variance indicated that Cr/K solution produced a greater axial dispersion than the Cr/Mg and Cr/Ca systems, probably due to some interaction between Cr3+ and K+ ions. The order of dynamic selectivity, provided by the cation uptake, was Cr3+ > Ca2+, Cr3+ > Mg2+ and Cr3+ > K+ for NaY zeolite and Ca2+ ~Cr3+, Mg2+ > Cr3+ and Cr3+ > K+ for NaX zeolite. Due to the more favorable mass transfer parameters and higher affinity for Cr3+, it was concluded that NaY zeolite was more efficient at chromium uptake in competitive systems.

  16. DETERMINATION OF ION EXCHANGE EQUILIBRIUM CONSTANTS FOR THE WEAK ACID CATION AND THE WEAK BASE ANION EXCHANGE RESINS

    Institute of Scientific and Technical Information of China (English)

    TAOZuyi; WANGChangshou

    1992-01-01

    The general procedure based on the potentiometric titration has developed.According to the procedure,the rational equilibrium constants of the ion exchange reactions RH/Na,RH/Ca,RH/Sr,RH/Ba for the weak acid cation exchange resin D725 and ROH/Cl for the weak base anion exchange resin D705 have been determined.

  17. Determination of {sup 135}Cs and {sup 137}Cs in environmental samples: A review

    Energy Technology Data Exchange (ETDEWEB)

    Russell, B.C., E-mail: ben.russell@npl.co.uk [GAU-Radioanalytical, Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, SO14 3ZH (United Kingdom); National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW (United Kingdom); Croudace, Ian W.; Warwick, Phil E. [GAU-Radioanalytical, Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, SO14 3ZH (United Kingdom)

    2015-08-26

    Radionuclides of caesium are environmentally important since they are formed as significant high yield fission products ({sup 135}Cs and {sup 137}Cs) and activation products ({sup 134}Cs and {sup 136}Cs) during nuclear fission. They originate from a range of nuclear activities such as weapons testing, nuclear reprocessing and nuclear fuel cycle discharges and nuclear accidents. Whilst {sup 137}Cs, {sup 134}Cs and {sup 136}Cs are routinely measurable at high sensitivity by gamma spectrometry, routine detection of long-lived {sup 135}Cs by radiometric methods is challenging. This measurement is, however, important given its significance in long-term nuclear waste storage and disposal. Furthermore, the {sup 135}Cs/{sup 137}Cs ratio varies with reactor, weapon and fuel type, and accurate measurement of this ratio can therefore be used as a forensic tool in identifying the source(s) of nuclear contamination. The shorter-lived activation products {sup 134}Cs and {sup 136}Cs have a limited application but provide useful early information on fuel irradiation history and have importance in health physics. Detection of {sup 135}Cs (and {sup 137}Cs) is achievable by mass spectrometric techniques; most commonly inductively coupled plasma mass spectrometry (ICP-MS), as well as thermal ionisation (TIMS), accelerator (AMS) and resonance ionisation (RIMS) techniques. The critical issues affecting the accuracy and detection limits achievable by this technique are effective removal of barium to eliminate isobaric interferences arising from {sup 135}Ba and {sup 137}Ba, and elimination of peak tailing of stable {sup 133}Cs on {sup 135}Cs. Isobaric interferences can be removed by chemical separation, most commonly ion exchange chromatography, and/or instrumental separation using an ICP-MS equipped with a reaction cell. The removal of the peak tailing interference is dependent on the instrument used for final measurement. This review summarizes and compares the analytical procedures

  18. Recent progress and applications of ion-exclusion/ion-exchange chromatography for simultaneous determination of inorganic anions and cations.

    Science.gov (United States)

    Nakatani, Nobutake; Kozaki, Daisuke; Mori, Masanobu; Tanaka, Kazuhiko

    2012-01-01

    One of the ultimate goals of ion chromatography is to determine both anions and cations found in samples with a single chromatographic run. In the present article, recent progress in ion-exclusion/ion-exchange chromatography for the simultaneous determinations of inorganic anions and cations are reviewed. Firstly, the principle and the control for the simultaneous separation and detection of analyte ions using ion-exclusion/cation-exchange chromatography with a weakly acidic cation-exchange column are outlined. Then, advanced chromatographic techniques in terms of analytical time, selectively and sensitivity are summarized. As a related method, ion-exclusion/anion-exchange chromatography with an anion-exchange column could be used for the simultaneous determination of inorganic nitrogen species, such as ammonium, nitrite and nitrate ions. Their usefulness and applications to water-quality monitoring and related techniques are also described.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Luminescent characteristic of the CsBr phosphor activated with Eu{sup 2+} and Mn{sup 2+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Téllez-Flores, E., E-mail: bluedays8i@hotmail.com [Programa de Posgrado en Ciencias (Física), Departamento de Investigación en Física, Universidad de Sonora, Rosales y Blvd. Transversal S/N, 83000 Hermosillo, Son., México (Mexico); Aceves, R., E-mail: raceves@cifus.uson.mx [Centro de Investigación en Física, Universidad de Sonora, Apartado Postal 5-88, 83190 Hermosillo, Son., México (Mexico); Pérez-Salas, R., E-mail: rperez@cifus.uson.mx [Centro de Investigación en Física, Universidad de Sonora, Apartado Postal 5-88, 83190 Hermosillo, Son., México (Mexico); Camarillo, I., E-mail: as99@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Delegación Iztapalapa, C.P. 09340 México D.F. (Mexico); Caldiño, U., E-mail: cald@xanum.uam.mx [Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, Col. Vicentina, Delegación Iztapalapa, C.P. 09340 México D.F. (Mexico)

    2013-12-15

    Spectra of excitation and emission were measured at RT and 15 K in crystals quenched (Q) of CsBr:Eu{sup 2+}, CsBr:Mn{sup 2+} and CsBr:Eu{sup 2+},Mn{sup 2+}. Emission bands at 444, 480, 520 and 570 nm with different relative intensities are generated in the samples after UV excitation. The blue band at 444 nm was ascribed with unknown clusters or aggregated centers (AC) of dipoles type Eu{sup 2+}–V{sub C}{sup −} and insulated dipole centers (IDC) like Eu{sup 2+}–O{sup 2−}. The bands at 480, 520 and 570 nm were assigned to Cs{sub 4}EuBr{sub 6} nanocrystals; AC containing MnBr{sub 4}{sup 2−} units in tetrahedral symmetry and another yet unidentified AC defect, respectively. In crystals of CsBr:Eu{sup 2+},Mn{sup 2+} the excitation and emission spectra taken at 15 K show no clear evidence of an energy transfer mechanism. Instead, the results suggest that the emission is produced by direct excitation of the ions of Eu{sup 2+} and Mn{sup 2+}. Accordingly, single- or double-doped CsBr crystals may contain the same type of defects, either AC and/or IDC. -- Highlights: • The PL consists of several overlapping bands in the entire visible region. • The emission bands were ascribed to dipoles, aggregated and nanocrystals of different nature. • No clear evidence of energy transfer, meaning Eu and Mn pairs are not formed. • The material shows potential characteristics for its use as LED to white emission.

  1. Charge exchange spectroscopy as a fast ion diagnostic on TEXTORa)

    Science.gov (United States)

    Delabie, E.; Jaspers, R. J. E.; von Hellermann, M. G.; Nielsen, S. K.; Marchuk, O.

    2008-10-01

    An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for active spectroscopy, injected counter the direction in which fast ions injected by the first beam are circulating, we can simultaneously measure a fast ion tail on the blue wing of the Dα spectrum while the beam emission spectrum is Doppler shifted to the red wing. An analysis combining the two parts of the spectrum offers possibilities to improve the accuracy of the absolute (fast) ion density profiles. Fast beam modulation or passive viewing lines cannot be used for background subtraction on this diagnostic setup and therefore the background has to be modeled and fitted to the data together with a spectral model for the slowing down feature. The analysis of the fast ion Dα spectrum obtained with the new diagnostic is discussed.

  2. Tungstate and Carbonate Ions Sorption Using Anion Exchangers AV-17-8 and Purolite A400

    Directory of Open Access Journals (Sweden)

    Chegrintsev S.

    2016-01-01

    Full Text Available The current paper shows the results of tungstate and carbonate ion sorption using strongly basic anion exchangers AV-17-8 and Purolite A400. It has been established that anion exchanger AV-17-8 in the chloride form with parameters of 168 g of tungstate ion and 157 g of carbonate ion per 1 kg of anion exchanger has the maximum capacity for the tungstate and carbonate ions.

  3. Advantages of ion-exchange chromatography for oligonucleotide analysis.

    Science.gov (United States)

    Cook, Ken; Thayer, Jim

    2011-05-01

    The rapid development of therapeutic oligonucleotides (ONs) has created a need for in-depth characterization of ONs, beyond previous requirements. The natural migration to LC-MS requires the use of chromatography with MS-compatible eluents to introduce the large, highly charged biopolymers into the mass spectrometer. Most frequently this employs ion-pair reversed-phase liquid chromatography, which may leave gaps in the characterization, but these can be filled with the use of high-resolution ion-exchange chromatography. Several classes of isobaric isomers are among the impurities that will require further separation prior to MS analysis. This review shows how the use of ion exchange as an additional orthogonal analytical method can be used as standalone or interfaced with MS to achieve the highest possible analytical coverage in the characterization and quantification of impurities present in single- and double-stranded ON formulations. Some of these techniques have been in use for some time and the importance of others is just being recognized.

  4. TRIPLICATE SODIUM IODIDE GAMMA RAY MONITORS FOR THE SMALL COLUMN ION EXCHANGE PROGRAM

    Energy Technology Data Exchange (ETDEWEB)

    Couture, A.

    2011-09-20

    This technical report contains recommendations from the Analytical Development (AD) organization of the Savannah River National Laboratory (SRNL) for a system of triplicate Sodium Iodide (NaI) detectors to be used to monitor Cesium-137 ({sup 137}Cs) content of the Decontaminated Salt Solution (DSS) output of the Small Column Ion Exchange (SCIX) process. These detectors need to be gain stabilized with respect to temperature shifts since they will be installed on top of Tank 41 at the Savannah River Site (SRS). This will be accomplished using NaI crystals doped with the alpha-emitting isotope, Americium-241({sup 241}Am). Two energy regions of the detector output will be monitored using single-channel analyzers (SCAs), the {sup 137}Cs full-energy {gamma}-ray peak and the {sup 241}Am alpha peak. The count rate in the gamma peak region will be proportional to the {sup 137}Cs content in the DSS output. The constant rate of alpha decay in the NaI crystal will be monitored and used as feedback to adjust the high voltage supply to the detector in response to temperature variation. An analysis of theoretical {sup 137}Cs breakthrough curves was used to estimate the gamma activity expected in the DSS output during a single iteration of the process. Count rates arising from the DSS and background sources were predicted using Microshield modeling software. The current plan for shielding the detectors within an enclosure with four-inch thick steel walls should allow the detectors to operate with the sensitivity required to perform these measurements. Calibration, testing, and maintenance requirements for the detector system are outlined as well. The purpose of SCIX is to remove and concentrate high-level radioisotopes from SRS salt waste resulting in two waste streams. The concentrated high-level waste containing {sup 137}Cs will be sent to the Defense Waste Processing Facility (DWPF) for vitrification and the low-level DSS will be sent to the Saltstone Production Facility (SPF

  5. Removal of Cs{sup +}, Sr{sup 2+}, and Co{sup 2+} ions from the mixture of organics and suspended solids aqueous solutions by zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Xiang Hong; Fang, Fang; Lu, Chun Hai [College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu (China); Zheng, Lei [Southwest University of Science and Technology, Key Laboratory of Solid Waste Treatment and Resource Recycle, Ministry of Education, Mianyang (China)

    2017-04-15

    Serving as an excellent adsorbent and inorganic ion exchanger in the water purification field, zeolite 4A has in this work presented a strong capability for purifying radioactive waste, such as Sr{sup 2+}, Cs{sup +}, and Co{sup 2+} in water. During the processes of decontamination and decommissioning of suspended solids and organics in low-level radioactive wastewater, the purification performance of zeolite 4A has been studied. Under ambient temperature and neutral condition, zeolite 4A absorbed simulated radionuclides such as Sr{sup 2+}, Cs{sup +}, and Co{sup 2+} with an absorption rate of almost 90%. Additionally, in alkaline condition, the adsorption percentage even approached 98.7%. After conducting research on suspended solids and organics of zeolite 4A for the treatment of radionuclides, it was found that the suspended clay was conducive to absorption, whereas the absorption of organics in solution was determined by the species of radionuclides and organics. Therefore, zeolite 4A has considerable potential in the treatment of radioactive wastewater.

  6. Ion-Exchange Chromatography: Basic Principles and Application.

    Science.gov (United States)

    Cummins, Philip M; Rochfort, Keith D; O'Connor, Brendan F

    2017-01-01

    Ion-Exchange Chromatography (IEC) allows for the separation of ionizable molecules on the basis of differences in charge properties. Its large sample-handling capacity, broad applicability (particularly to proteins and enzymes), moderate cost, powerful resolving ability, and ease of scale-up and automation have led to it becoming one of the most versatile and widely used of all liquid chromatography (LC) techniques. In this chapter, we review the basic principles of IEC, as well as the broader criteria for selecting IEC conditions. By way of further illustration, we outline basic laboratory protocols to partially purify a soluble serine peptidase from bovine whole brain tissue, covering crude tissue extract preparation through to partial purification of the target enzyme using anion-exchange chromatography. Protocols for assaying total protein and enzyme activity in both pre- and post-IEC fractions are also described.

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

    Directory of Open Access Journals (Sweden)

    T.M. Zewail

    2015-03-01

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

  8. The modification of ion exchange heterogeneous catalysts for biodiesel synthesis

    Science.gov (United States)

    Hartono, R.; Mulia, B.; Sahlan, M.; Utami, T. S.; Wijanarko, Anondho; Hermansyah, Heri

    2017-03-01

    Conventionally, biodiesel is produced by using the homogeneous catalyst which has difficulty in high cost of the separation process. The heterogeneous catalysts ion exchange resin by its Solid phase can make an easier separation process, able to be reactivated and used repeatedly. In this research, the heterogeneous catalyst from various source such as Lewatit macro porous resin, Amberlite gel resin and natural zeolite bayah was investigated their performance to produced biodiesel from used cooking oil. Initially, the preparation of the ion exchange process with variations in time, temperature, the concentration of HCl and NaOH solution was investigated. Then, the activity of heterogeneous catalyst to produced biodiesel under the variation of stirring rate, zeolite particle size, and comparison of different ion exchange catalysts were also investigated. Finally, the stability test and regeneration treatment were also investigated. The optimum operating conditions of biodiesel synthesis process is at the temperature of 60 °C for 2 h with a stirring speed of 700 rpm. Natural zeolite Bayah with 6 M of NaOH solution produced 16.19%, Amberlite gel with 6 M HCL produced 65.22% of biodiesel yield and material Lewatit macro porous with 6 M of NaOH solution produced 85.94% as the maximum result. As the best result, Material Lewatit macro porous selected as the material which was used in the variation of stirring speed, temperature, and reaction time, the concentration of base and stability test. According to the results of analysis, calculations yield methyl oleic HPLC produced by Lewatit macro porous with 6 M NaOH at 62.95%.

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

    Science.gov (United States)

    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.

  10. Modified ion exchange resins - synthesis and properties. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Doescher, F.; Klein, J.; Pohl, F.; Widdecke, H.

    1982-01-22

    Sulfomethylated resins are prepared by polymer analogous reactions, starting from macroporous poly(styrene-co-divinylbenzene) matrices. Different reaction paths are discussed and used in the synthesis. Sulfomethylation can be achieved by reaction of a chloromethylated resin with dimethyl sulfide and sodium sulfonate or alternatively by oxidation of polymer-bound thiol groups. Both methods give high conversions as shown by IR spectra and titration of the sulfonic acid groups. Poly(1-(4-hydroxysulfomethylphenyl)ethylene) (3) is obtained by reaction of poly(1-(4-hydroxyphenyl)ethylene) (2) resin with formaldehyde/sodium sulfonate. The thermal stability, catalytic activity, and ion exchange equilibria of the sulfomethylated resin are investigated.

  11. Multistep ion exchange processes of gradient refractive index rod lens.

    Science.gov (United States)

    Lv, Hao; Liu, Aimei; Tong, Jufang; Yi, Xunong; Li, Qianguang; Wang, Xinmin; Ding, Yaoming

    2011-01-01

    A mathematical model for research on the refractive index profile (RIP) of multistep ion exchange processes (IEPs) of gradient refractive index rod lenses (GRINs) is established by the different initial condition and boundary condition, based on the Fickian diffusion equation. GRIN rod lenses have been fabricated using the three-step IEPs. Research results indicate that the experimental deviations of refractive index (DRI) are in good agreement with the theoretical data. The DRI of three-step IEPs is superior to the one- and two-step IEPs and smaller than 10(-5).

  12. Predicting Carbonate Ion Transport in Alkaline Anion Exchange Materials

    Science.gov (United States)

    2012-01-01

    Electrochemical Society , 2013. 2. Wilson K. S. Chiu, "Part 1. Role of the 3-D Electrode Microstructure on Charge Transfer, Mass Transfer, and Electrochemical Reactions in Solid Oxide Fuel Cells; Part 2. Ion and Water Transport in Alkaline Anion Exchange Membranes," technical seminar for the Army Research Laboratory (host: Dr. Deryn Chu), Adelphi, MD, August 13, 2012. (c) Presentations Number of Presentations: 2.00 Non Peer-Reviewed Conference Proceeding publications (other than abstracts): Received Paper TOTAL: Number of Non Peer-Reviewed

  13. Complexity analysis of the glutamic acid ion-exchanged wastewater

    Institute of Scientific and Technical Information of China (English)

    林艳; 王瑞明; 徐国华; 王腾飞; 井瑞洁

    2008-01-01

    In this paper,the glutamic acid ion-exchanged wastewater has been studied.Kjeldahl determination method,Fehling reagent.muffle furnace method.and so on were used.It can be sure that the wastewater's COD is 50250 mg/L.and total solids is 13.76%.it contains:glutamic acid 0.3%:total reducing sugar 0.414%;fat 0.4274%;ammonium sulphate 10.0758%;microbial protein 0.8045%;ash 0.27%:others 1.4683%.

  14. Synthesis, characterization and evaluation of nano-zirconium vanadate ion exchanger by using three different preparation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Latif, M.M., E-mail: amona1911@yahoo.com [Fabrication Technology Department, Advanced Technology and New Materials Research Institute (ATNMRI), Mubarak City for Scientific Research and Technology Applications (MuCSAT), Alexandria (Egypt); Elkady, M.F., E-mail: maroelkady@yahoo.com [Fabrication Technology Department, Advanced Technology and New Materials Research Institute (ATNMRI), Mubarak City for Scientific Research and Technology Applications (MuCSAT), Alexandria (Egypt)

    2011-01-15

    Sol-gel, homogeneous precipitation and hydrothermal synthesis are three different preparation techniques have been used as an attempt to synthesize nano-zirconium vanadate with properties suitable to be used as ion exchangers. The impact of the synthetic preparation variables such as the reactant concentrations, reaction temperature and reaction time on the ion exchange capacity of the produced ion exchanger has been considered for each preparation technique. One sample from each preparation technique having the largest ion exchange capacity has been selected to be physically and chemically characterized using various analytical techniques such as XRD, TGA, DSC, pH titration, FTIR and SEM in order to determine the properties of the ion exchanger produced from each technique. For all the studied ZrV samples it can be presumed that they have the ion exchange affinity sequences for alkali metal ions K > Na > Li, the order for the alkaline earth metals is Ba > Ca > Mg and their affinity for radioactive metals follow Cs > Sr. Moreover, the prepared materials are of high thermal and radiation stabilities. Also they have high chemical stabilities toward wide concentration ranges of acid, basic as well as polar solvents. It has been deduced from the X-ray analysis that ZrV produced from the sol-gel technique has an amorphous structural. While those produced from the homogeneous precipitation and hydrothermal synthesis techniques, in the nano-scale have semi-crystalline structural. Furthermore, SEM confirms that particle size of the all studied prepared ZrV samples have nano-diameters of range 50-60 nm. Specific surface area of the three different prepared ion exchangers are found to be equal to 187, 192 and 320 m{sup 2}/g for sol-gel, homogeneous precipitation and hydrothermal, respectively. A tentative structural formula of Zr(OH){sub 2}(HVO{sub 4}){sub 2}.2H{sub 2}O has been proposed for all studied samples on the basis of on FTIR, DSC and TGA results.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. ION EXCHANGE SUBSTANCES BY SAPONIFICATION OF ALLYL PHOSPHATE POLYMERS

    Science.gov (United States)

    Kennedy, J.

    1959-04-14

    An ion exchange resin having a relatively high adsorption capacity tor uranyl ion as compared with many common cations is reported. The resin comprises an alphyl-allyl hydrogen phosphate polymer, the alphyl group being either allyl or a lower alkyl group having up to 5 carbon atoins. The resin is prepared by polymerizing compounds such as alkyl-diallyl phosphate and triallyl phosphate in the presence of a free radical generating substance and then partially hydrolyzing the resulting polymer to cause partial replacement of organic radicals by cations. A preferred free radical gencrating agent is dibenzoyl peroxide. The partial hydrolysis is brought about by refluxing the polymer with concentrated aqueous NaOH for three or four hours.

  17. Unravelling the secrets of Cs controlled secondary ion formation: Evidence of the dominance of site specific surface chemistry, alloying and ionic bonding

    Science.gov (United States)

    Wittmaack, Klaus

    2013-03-01

    Exposure of ion bombarded solids to Cs gives rise to a very strong enhancement of the yields of negatively charged secondary ions and, concurrently, to a lowering of positive ion yields. The phenomena have been explored in a large number of experimental and theoretical studies but attempts to clarify the mechanism of ion formation were not as successful as assumed. This review examines the state of the art in Cs controlled secondary ion mass spectrometry (SIMS) in great detail, with due consideration of low-energy alkali-ion scattering. In very basic studies on alkali induced secondary ion yield changes, sub-monolayer quantities of Cs or Li were deposited on the sample surface, followed by low-fluence ion bombardment, to avoid significant damage. If SIMS is applied to characterise the composition of solid materials, the simplest approach to achieving sample erosion as well as high negative-ion yields is bombardment with primary ions of Cs. Two other methods of sample loading with Cs provide more flexibility, (i) exposure to a collimated beam of Cs vapour and concurrent bombardment with high-energy non-Cs ions and (ii) the mixed-beam approach involving quasi-simultaneous bombardment with Cs and Xe ions. Both concepts have the advantage that undesirable sample overload with Cs can be avoided. High Cs concentrations reduce the formation probability of target specific molecular ions and lower the yields of all types of positive secondary ions, including Cs+, M+, X+, MCs+ and XCs+ (M and X denoting matrix and impurity elements). Quantitative SIMS analysis using MCs+ and XCs+ ions appears feasible, provided the Cs coverage is kept below about 5%. The semi-classical model of resonant charge transfer, also known as the tunnelling model, has long been considered a solid framework for the interpretation of Cs and Li based SIMS data. The model predicts ionisation probabilities for cases in which, at shallow distances from the surface, the affinity (ionisation) level of the

  18. Ion-Isotopic Exchange Reaction Kinetics using Anion Exchange Resins Dowex 550A LC and Indion-930A

    Directory of Open Access Journals (Sweden)

    P.U. Singare

    2014-06-01

    Full Text Available The present paper deals with the characterization of ion exchange resins Dowex 550A LC and Indion-930A based on kinetics of ion-isotopic exchange reactions for which the short lived radioactive isotopes 131I and 82Br were used as a tracers. The study was performed for different concentration of ionic solution varying from 0.001 mol/L to 0.004 mol/L and temperature in the range of 30.0 °C to 45.0 °C. The results indicate that as compared to bromide ion-isotopic exchange reaction, iodide exchange reaction take place at the faster rate. For both the ion-isotopic exchange reactions, under identical experimental conditions, the values of specific reaction rate increases with increase in the ionic concentration and decreases with rise in temperature. It was observed that at 35.00C, 1.000 g of ion exchange resins and 0.002 mol/L labeled iodide ion solution for iodide ion-isotopic exchange reaction, the values of specific reaction rate (min-1, amount of ion exchanged (mmol, initial rate of ion exchange (mmol/min and log Kd were 0.270, 0.342, 0.092 and 11.8 respectively for Dowex 550A LC resin, which was higher than the respective values of 0.156, 0.241, 0.038 and 7.4 as that obtained for Indion-930A resins. From the results, it appears that Dowex 550A LC resins show superior performance over Indion-930A resins under identical experimental conditions.

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

    Science.gov (United States)

    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.

  20. Study of pure and Pb{sup 2+} ions doped CsI crystals under alpha particles excitations

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Maria da Conceicao Costa; Madi Filho, Tufic; Hamada, Margarida Mizue, E-mail: macoper@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Scintillation crystals have been used in various fields, such as high energy physics, nuclear instrumentation, radiation measurements, medical imaging, nuclear tomography, astrophysics and other fields of science and engineering. For these applications, the development of good performance scintillation crystals is required. Scintillation crystals based on cesium iodide (CsI) matrix are matters with relatively low hygroscope, easy handling and low cost, characteristics that favor their use as radiation detectors. In this work, pure CsI crystal and lead doped CsI crystals were grown using the Bridgman vertical technique. The concentration of the lead doping element (Pb) was studied in the range of 10{sup -2} M to 5x10{sup -4} M. The distribution of the doping element in the crystalline volume was determined by flame atomic absorption. The CsI:Pb crystal with nominal concentration of 10{sup -3} M was cut into 14 slices of 6 mm. The results show a higher concentration at the top of the crystal with a decrease in the initial phase of growth. The dopant concentration of Pb showed good uniformity from the slice 2 to the slice 12: the region is, therefore, suitable for use as radiation detector. The luminescence emission of these crystals were measured. A predominant luminescence band near 450 nm and a single broad band around 320 nm were found with the addition of the Pb{sup 2+} ions. Analyses were carried out to evaluate the developed scintillators, concerning alpha particles. The resolution of 5.6% was obtained for the CsI:Pb 5x10{sup -4} M crystal, when excited with alpha particles from a {sup 241}Am source, with energy of 5.54 MeV. (author)

  1. Controlled oxidative protein refolding using an ion-exchange column.

    Science.gov (United States)

    Langenhof, Marc; Leong, Susanna S J; Pattenden, Leonard K; Middelberg, Anton P J

    2005-04-01

    Column-based refolding of complex and highly disulfide-bonded proteins simplifies protein renaturation at both preparative and process scale by integrating and automating a number of operations commonly used in dilution refolding. Bovine serum albumin (BSA) was used as a model protein for refolding and oxido-shuffling on an ion-exchange column to give a refolding yield of 55% after 40 h incubation. Successful on-column refolding was conducted at protein concentrations of up to 10 mg/ml and refolded protein, purified from misfolded forms, was eluted directly from the column at a concentration of 3 mg/ml. This technique integrates the dithiothreitol removal, refolding, concentration and purification steps, achieving a high level of process simplification and automation, and a significant saving in reagent costs when scaled. Importantly, the current result suggests that it is possible to controllably refold disulfide-bonded proteins using common and inexpensive matrices, and that it is not always necessary to control protein-surface interactions using affinity tags and expensive chromatographic matrices. Moreover, it is possible to strictly control the oxidative refolding environment once denatured protein is bound to the ion-exchange column, thus allowing precisely controlled oxido-shuffling.

  2. Ion exchange at TNX using the SKID unit

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-10-21

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

  3. Isotope exchange by Ion Cyclotron Wall Conditioning on JET

    Energy Technology Data Exchange (ETDEWEB)

    Wauters, T., E-mail: t.wauters@fz-juelich.de [Laboratory for Plasma Physics, ERM/KMS, TEC Partner, 1000 Brussels (Belgium); Douai, D.; Kogut, D. [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Lyssoivan, A. [Laboratory for Plasma Physics, ERM/KMS, TEC Partner, 1000 Brussels (Belgium); Brezinsek, S. [Forschungszentrum Jülich, Institut für Energie- und Klimaforschung Plasmaphysik, 52425 Jülich (Germany); Belonohy, E. [Max-Planck Institut für Plasmaphysik, 85748 Garching (Germany); Blackman, T. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Bobkov, V. [Max-Planck Institut für Plasmaphysik, 85748 Garching (Germany); Crombé, K. [Laboratory for Plasma Physics, ERM/KMS, TEC Partner, 1000 Brussels (Belgium); Drenik, A. [Jožef Stefan Institute, 1000 Ljubljana (Slovenia); Graham, M. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Joffrin, E. [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Lerche, E. [Laboratory for Plasma Physics, ERM/KMS, TEC Partner, 1000 Brussels (Belgium); Loarer, T. [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France); Lomas, P.L.; Mayoral, M.-L.; Monakhov, I. [JET-EFDA, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); Oberkofler, M. [Max-Planck Institut für Plasmaphysik, 85748 Garching (Germany); Philipps, V. [Forschungszentrum Jülich, Institut für Energie- und Klimaforschung Plasmaphysik, 52425 Jülich (Germany); Plyusnin, V. [IST, Instituto de Plasmas e Fusão Nuclear, 1049-001 Lisboa (Portugal); and others

    2015-08-15

    The isotopic exchange efficiencies of JET Ion Cyclotron Wall Conditioning (ICWC) discharges produced at ITER half and full field conditions are compared for JET carbon (C) and ITER like wall (ILW). Besides an improved isotope exchange rate on the ILW providing cleaner plasma faster, the main advantage compared to C-wall is a reduction of the ratio of retained discharge gas to removed fuel. Complementing experimental data with discharge modeling shows that long pulses with high (∼240 kW coupled) ICRF power maximizes the wall isotope removal per ICWC pulse. In the pressure range 1–7.5 × 10{sup −3} Pa, this removal reduces with increasing discharge pressure. As most of the wall-released isotopes are evacuated by vacuum pumps in the post discharge phase, duty cycle optimization studies for ICWC on JET-ILW need further consideration. The accessible reservoir by H{sub 2}-ICWC at ITER half field conditions on the JET-ILW preloaded by D{sub 2} tokamak operation is estimated to be 7.3 × 10{sup 22} hydrogenic atoms, and may be exchanged within 400 s of cumulated ICWC discharge time.

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

    Science.gov (United States)

    Jorgensen, T C; Weatherley, L R

    2003-04-01

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

  5. INTERACTION OF AMINO ACID WITH ION EXCHANGE RESIN Ⅲ.FURTHER INVESTIGA TION OF SUPEREQUIVALENT ADSORPTION MECHANISM OF AMINO ACID ON ION EXCHANGE RESIN

    Institute of Scientific and Technical Information of China (English)

    ZHANGHui; SHAOTong; 等

    1994-01-01

    The adsorption isotherms of glycine,alanine and oxidized glutathion on strong acid cation and strong base anion exchange resins from aqueous solutions were measured and the superequivalent adsorptions of glycine and alanine observed.The infrared spectra of glycine adsorbed on the cation and the anion exchange resins,001×7 and 201×7,were measured.From these results,it is concluded that the amino acid adsorption on the ion exchange resin proceeds not only through ion exchange and proton transfer mechanisms,but also through aminecarboxylate interaction between the adsorbed amino acid molecules,and the formation of second layer of amino acid molecules is the mechanism of superequivalent adsorption of amino acid,the carboxylate or amine groups of the first layer of amino acid molecules on the ion exchange resin act as the exchange sites for the second layer of amino acid molecules.

  6. High Level Waste System Impacts from Small Column Ion Exchange Implementation

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, D. J.; Hamm, L. L.; Aleman, S. E.; Peeler, D. K.; Herman, C. C.; Edwards, T. B.

    2005-08-18

    The objective of this task is to identify potential waste streams that could be treated with the Small Column Ion Exchange (SCIX) and perform an initial assessment of the impact of doing so on the High-Level Waste (HLW) system. Design of the SCIX system has been performed as a backup technology for decontamination of High-Level Waste (HLW) at the Savannah River Site (SRS). The SCIX consists of three modules which can be placed in risers inside underground HLW storage tanks. The pump and filter module and the ion exchange module are used to filter and decontaminate the aqueous tank wastes for disposition in Saltstone. The ion exchange module contains Crystalline Silicotitanate (CST in its engineered granular form is referred to as IONSIV{reg_sign} IE-911), and is selective for removal of cesium ions. After the IE-911 is loaded with Cs-137, it is removed and the column is refilled with a fresh batch. The grinder module is used to size-reduce the cesium-loaded IE-911 to make it compatible with the sludge vitrification system in the Defense Waste Processing Facility (DWPF). If installed at the SRS, this SCIX would need to operate within the current constraints of the larger HLW storage, retrieval, treatment, and disposal system. Although the equipment has been physically designed to comply with system requirements, there is also a need to identify which waste streams could be treated, how it could be implemented in the tank farms, and when this system could be incorporated into the HLW flowsheet and planning. This document summarizes a preliminary examination of the tentative HLW retrieval plans, facility schedules, decontamination factor targets, and vitrified waste form compatibility, with recommendations for a more detailed study later. The examination was based upon four batches of salt solution from the currently planned disposition pathway to treatment in the SCIX. Because of differences in capabilities between the SRS baseline and SCIX, these four batches were

  7. High Level Waste System Impacts from Small Column Ion Exchange Implementation

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, D. J.; Hamm, L. L.; Aleman, S. E.; Peeler, D. K.; Herman, C. C.; Edwards, T. B.

    2005-08-18

    The objective of this task is to identify potential waste streams that could be treated with the Small Column Ion Exchange (SCIX) and perform an initial assessment of the impact of doing so on the High-Level Waste (HLW) system. Design of the SCIX system has been performed as a backup technology for decontamination of High-Level Waste (HLW) at the Savannah River Site (SRS). The SCIX consists of three modules which can be placed in risers inside underground HLW storage tanks. The pump and filter module and the ion exchange module are used to filter and decontaminate the aqueous tank wastes for disposition in Saltstone. The ion exchange module contains Crystalline Silicotitanate (CST in its engineered granular form is referred to as IONSIV{reg_sign} IE-911), and is selective for removal of cesium ions. After the IE-911 is loaded with Cs-137, it is removed and the column is refilled with a fresh batch. The grinder module is used to size-reduce the cesium-loaded IE-911 to make it compatible with the sludge vitrification system in the Defense Waste Processing Facility (DWPF). If installed at the SRS, this SCIX would need to operate within the current constraints of the larger HLW storage, retrieval, treatment, and disposal system. Although the equipment has been physically designed to comply with system requirements, there is also a need to identify which waste streams could be treated, how it could be implemented in the tank farms, and when this system could be incorporated into the HLW flowsheet and planning. This document summarizes a preliminary examination of the tentative HLW retrieval plans, facility schedules, decontamination factor targets, and vitrified waste form compatibility, with recommendations for a more detailed study later. The examination was based upon four batches of salt solution from the currently planned disposition pathway to treatment in the SCIX. Because of differences in capabilities between the SRS baseline and SCIX, these four batches were

  8. RATE LAW AND ITS MOMENT EXPRESSIONS FOR PELLICULAR ION EXCHANGE MATERIALS OF VARIOURS SHAPES

    Institute of Scientific and Technical Information of China (English)

    YangGengliang; ZhangXiaomin; 等

    1994-01-01

    In this paper,the kinetic moment expressions and rate laws are derived for pellicular ion exchange materials with various geometrical forms under the conditions that ion exchange rate is controlled by both the partical diffusion and the film diffusion in finite solution volume.In addition,for strong acidic cation ion exchange fibre,by using the equations obtained we calculated the partical diffusion coefficients and the transfer coefficients in the film under different experimental conditions.

  9. Programmatic Re-Evaluation of Ion Exchange as a 1st Generation ITP Replacement

    Energy Technology Data Exchange (ETDEWEB)

    Scott, A.B. [Westinghouse Savannah River Company, AIKEN, SC (United States)

    1998-09-01

    This re-evaluation differs from previous work in that (1) the Ion Exchange option was evaluated from a standpoint assuming that ITP would never start up, thus Ion Exchange was the only viable option, (2) the DOE prescribed balanced assumptions were quite different than the WSRC Assumptions used previously, and (3) other Site events and changes within HLWM have tended to reduce the disadvantages of Ion Exchange relative to ITP as the first generation salt decontamination process.

  10. Potassium-and silver-double-ion-exchanged slab glass waveguides: characterization and modeling.

    Science.gov (United States)

    Auger, P L; Najafi, S I

    1994-06-01

    Double-ion-exchanged glass waveguides are made first by a potassium-ion exchange followed by a silver-ion exchange. The inverse WKB method is used to determine the index profile. It is shown that a combination of a truncated quadratic function and a complementary error function represents the refractive index best. A direct WKB method is employed to find the maximum index change and the diffusion coefficient of the second exchange process. The concentration of silver, potassium, and sodium ions are measured by an x-ray photoelectron spectroscopy technique. The results agree well with the index profile when a quadratic function is used.

  11. Reactive ion exchange synthesis of high pure nano-CeO2

    Institute of Scientific and Technical Information of China (English)

    ZHU Shao-min; FENG Ying-chun; WEN Yang; JIANG Yu-ling

    2010-01-01

    This paper presents a reactive ion exchange synthesis method of nano-CeO2 with positive cerium preexchanged ion exchange resin as precursor and (NH4)2CO3 as precipitant.The resultant precipitate was dried at 100 ℃ for 12 h and then was calcined at 500 K in air.The effects of ion exchange temperature and reaction time on the diameter of CeO2 particle were discussed.The TEM images show that the samples prepared with one step reactive ion exchange method are composed of nano-club with the length about 300 nm.

  12. Investigations on Cs-free alternatives for negative ion formation in a low pressure hydrogen discharge at ion source relevant parameters

    Science.gov (United States)

    Kurutz, U.; Friedl, R.; Fantz, U.

    2017-07-01

    Caesium (Cs) is applied in high power negative hydrogen ion sources to reduce a converter surface’s work function and thus enabling an efficient negative ion surface formation. Inherent drawbacks with the usage of this reactive alkali metal motivate the search for Cs-free alternative materials for neutral beam injection systems in fusion research. In view of a future DEMOnstration power plant, a suitable material should provide a high negative ion formation efficiency and comply with the RAMI issues of the system: reliability, availability, maintainability, inspectability. Promising candidates, like low work function materials (molybdenum doped with lanthanum (MoLa) and LaB6), as well as different non-doped and boron-doped diamond samples were investigated in this context at identical and ion source relevant parameters at the laboratory experiment HOMER. Negative ion densities were measured above the samples by means of laser photodetachment and compared with two reference cases: pure negative ion volume formation with negative ion densities of about 1× {10}15 {{{m}}}-3 and the effect of H- surface production using an in situ caesiated stainless steel sample which yields 2.5 times higher densities. Compared to pure volume production, none of the diamond samples did exhibit a measurable increase in H- densities, while showing clear indications of plasma-induced erosion. In contrast, both MoLa and LaB6 produced systematically higher densities (MoLa: ×1.60 LaB6: ×1.43). The difference to caesiation can be attributed to the higher work functions of MoLa and LaB6 which are expected to be about 3 eV for both compared to 2.1 eV of a caesiated surface.

  13. Ion Exchange Column Tests Supporting Technetium Removal Resin Maturation

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-20

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

  14. FORMATION OF LUMINESCENT OPTICAL WAVEGUIDES IN SILICATE GLASS MATRIX BY THE ION-EXCHANGE TECHNIQUE

    Directory of Open Access Journals (Sweden)

    I. A. Dyomichev

    2015-01-01

    Full Text Available We present spectra of the alkali-silicate glasses with copper ions in near-surface area, introduced by ion exchange of different temperature and duration. It is shown that the reduction of Cu2+ in the near-surface area causes existence of Cu+ and neutral atoms in glass after the ion-exchange in divalent salt. The ion-exchange itself involves only Cu+ and Na+ ions. The formation of subnanometer clusters Cun is due to neutral copper atoms staying in near-surface zone. We have shown that the waveguide layer in near-surface area, made by ion-exchange, has а visible luminescence with the excitation by UVradiation. At the same time, the contribution to luminescence is made by Cu+ ions, molecular clusters Cun and by dimers Cu+ - Cu+ . During the high-temperature ion-exchange at 600 °С the formation and destruction equilibrium shift of molecular clusters Cun can be seen. An hour ion-exchange leads to molecular clusters Cun destruction, while at time periods less than 30 min and around 18 hours it leads to the formation of Cun. The sample turns green after 18,5 hours ion-exchange showing formation of a considerable amount of divalent copper ions Cu2+ therein.

  15. Charge Exchange Collisions between Ultracold Fermionic Lithium Atoms and Calcium Ions

    CERN Document Server

    Haze, Shinsuke; Saito, Ryoichi; Mukaiyama, Takashi

    2014-01-01

    An observation of charge exchange collisions between ultracold fermionic 6Li atoms and 40Ca+ ions is reported. The reaction product of the charge exchange collision is dentified via mass spectrometry where the motion of the ions is excited parametrically. We measure the cross section of the charge exchange collisions between the 6Li atoms in the ground state and the 40Ca+ ions in the ground and metastable excited states. Investigation of the inelastic collision characteristics in the atom-ion mixture is an important step toward ultracold chemistry based on ultracold atoms and ions.

  16. Determination of effective capacities of ion-exchangeable materials by measuring the equilibrium conductivity.

    Science.gov (United States)

    Okabe, Toshiaki; Yokoyama, Yukio

    2010-01-01

    The effective ion-exchange capacities of ion-exchange materials were determined by measuring the change in the equilibrium conductivity of a column packed with analyte. The developed instrumental method can provide effective ion-exchange capacities for both cation and anion exchangers with simple operations. The cation-exchange capacity of a weak-acid cation-exchange resin (TSKgel SuperIC-Cation column) depended on the conditioning pH and the molar concentration of the conditioning agent. Plots of effective cation-exchange capacities over the conditioning pH exhibited three inflection points, suggesting the presence of two carboxy groups and one phenolic OH group in the resin, probably due to the inherent base polymer. This method was applied to several commercial analytical columns for ion chromatography, and could provide scientifically useful results for characterizing the resin properties.

  17. Ion exchange and dehydration experimental studies of clinoptilolite: Implications to zeolite dating

    Energy Technology Data Exchange (ETDEWEB)

    WoldeGabriel, G.

    1995-02-01

    Variable effects were noted on the argon (Ar) and potassium (K) contents of clinoptilolite fractions used in ion-exchange and dehydration experiments. The K contents of clinoptilolite fractions were differently affected during cation exchange with Ca-, Cs-, K-, and Na-chloride solutions. Ar was generally less affected during these experiments, except for a Na-clinoptitolite fraction exchanged for five days. Loss of Ar during organic heavy-liquid treatment and cleaning using acetone and deionized water does occur, as indicated by comparing the amounts of radiogenic Ar of treated and untreated fractions. Moreover, a regular decrease in radiogenic Ar contents was noted in clinoptilolite fractions during dehydration experiments at different temperatures for 16 hours. Comparable losses do not occur from saturated samples that were heated in 100 C for more than five months. Water appears to play a vital role in stabilizing the clinoptilolite framework structure and in the retention of Ar. The radiogenic Ar depletion pattern noted in clinoptilolite fractions dehydrated in unsaturated environment at different temperatures is similar to variations in the amount of radiogenic Ar observed in clinoptilolite samples from the unsaturated zone of an altered tuff. These results can be used to evaluate the extent of zeolitic water (and hence Ar) retention in unsaturated geologic settings. The utility of alkali zeolites (e.g., phillipsite, clinoptilolite, and mordenite) from low-temperature, open-hydrologic alteration as potential dateable minerals was evaluated using the K/Ar method as part of the Yucca Mountain Site Characterization Project, which is evaluating Yucca Mountain, Nevada, as a potential high-level radioactive waste repository site.

  18. Electrodialysis-ion exchange for the separation of dissolved salts

    Energy Technology Data Exchange (ETDEWEB)

    Baroch, C.J. [Wastren, Inc., Westminster, CO (United States); Grant, P.J. [Wastren, Inc., Hummelstown, PA (United States)

    1995-10-01

    The Department of Energy generates and stores a significant quantity of low level, high level, and mixed wastes. As some of the DOE facilities are decontaminated and decommissioned, additional and possibly different forms of wastes will be generated. A significant portion of these wastes are aqueous streams containing acids, bases, and salts, or are wet solids containing inorganic salts. Some of these wastes are quite dilute solutions, whereas others contain large quantities of nitrates either in the form of dissolved salts or acids. Many of the wastes are also contaminated with heavy metals, radioactive products, or organics. Some of these wastes are in storage because a satisfactory treatment and disposal processes have not been developed. There is considerable interest in developing processes that remove or destroy the nitrate wastes. Electrodialysis-Ion Exchange (EDIX) is a possible process that should be more cost effective in treating aqueous waste steams. This report describes the EDIX process.

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

    Science.gov (United States)

    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.

  20. Ion exchange of ammonium in natural and synthesized zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yifei [College of Biology and Chemical Engineering, Jiaxing University, Jiaxin, Zhejiang 314001 (China); Department of Chemistry, XiXi Campus, Zhejiang University, Hangzhou, Zhejiang 310028 (China)], E-mail: yifeiwang0206@yahoo.com.cn; Lin Feng [Department of Chemistry, XiXi Campus, Zhejiang University, Hangzhou, Zhejiang 310028 (China); Pang Wenqin [Department of Chemistry, State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun, Jilin 130023 (China)

    2008-12-30

    In this study, zeolite Na-P and Na-Y was prepared by hydrothermal treatment of the Chinese natural clinoptilolite with NaOH. The ion exchange of NH{sub 4}{sup +} into the three zeolites in the temperature range of 288-333 K was also investigated, and the thermodynamic parameters were calculated. The selectivity sequence for NH{sub 4}{sup +} entering the sodium form of the three materials was Na-clinoptilolite > Na-Y > Na-P, as indicated by values of {delta}G{sup o}. The results demonstrated that the Si/Al molar ratio of zeolites determined the selectivity for NH{sub 4}{sup +}.

  1. Investigation of the Ion-Exchange Behavior of Zeolite Y in the Presence of Resin

    Institute of Scientific and Technical Information of China (English)

    Zhang Yi; Zheng Jinyu; Liu Zhongqing; Gao Xiuzhi; Luo Yibin; Zong Baoning

    2015-01-01

    Ion-exchange process of zeolite Y using ammonium-type resin as an exchange reagent was successfully carried out. The effect of temperature, space velocity and ion concentration on the breakthrough curves was carefully investigated. At the ifrst exchange section, the maximum proportion of qualiifed zeolites (QR) was obtained at a temperature of 70℃, a weight hourly space velocity of 0.61 h-1, and an ion concentration of 197 mg/L. The minimum length of mass-transfer zone (MTZ) of the resin bed was achieved at a temperature of 70℃, a space velocity of 0.61 h-1, and an ion concentration of 423 mg/L. At the second exchange section, the length of MTZ of the resin bed was signiifcantly increased, and the exchange of Na+ions contained in zeolite Y was more dififcult than that achieved at the ifrst exchange section. In both the ifrst and the second exchange sections, the zeolite Y subjected to ion exchange with the resin maintained the similar physical and chemi-cal properties as compared to those exchanged by the conventional approaches, but the zeolite Y, which was obtained after ion exchange, contained a signiifcantly lower content of Na2O.

  2. Zinc--bromide secondary cell. [C anode, C or Zr cathode with ion exchange diaphragm between

    Energy Technology Data Exchange (ETDEWEB)

    Leddy, J.J.; Gritzner, G.

    1975-12-30

    A zinc-bromine secondary cell is divided into two compartments by an ion exchange diaphragm. The electrolyte system includes an essentially bromide-ion-free, aqueous solution containing a zinc ion as an anolyte and a bromide ion containing catholyte. A method of operating the cell is disclosed. 2 figures, 2 tables. (auth)

  3. Study of plasma off-gas treatment from spent ion exchange resin pyrolysis.

    Science.gov (United States)

    Castro, Hernán Ariel; Luca, Vittorio; Banchi, Hugo Luis

    2017-03-23

    Polystyrene divinylbenzene-based ion exchange resins are employed extensively within nuclear power plants (NPPs) and research reactors for purification and chemical control of the cooling water system. To maintain the highest possible water quality, the resins are regularly replaced as they become contaminated with a range of isotopes derived from compromised fuel elements as well as corrosion and activation products including (14)C, (60)Co, (90)Sr, (129)I, and (137)Cs. Such spent resins constitute a major proportion (in volume terms) of the solid radioactive waste generated by the nuclear industry. Several treatment and conditioning techniques have been developed with a view toward reducing the spent resin volume and generating a stable waste product suitable for long-term storage and disposal. Between them, pyrolysis emerges as an attractive option. Previous work of our group suggests that the pyrolysis treatment of the resins at low temperatures between 300 and 350 °C resulted in a stable waste product with a significant volume reduction (>50%) and characteristics suitable for long-term storage and/or disposal. However, another important issue to take into account is the complexity of the off-gas generated during the process and the different technical alternatives for its conditioning. Ongoing work addresses the characterization of the ion exchange resin treatment's off-gas. Additionally, the application of plasma technology for the treatment of the off-gas current was studied as an alternative to more conventional processes utilizing oil- or gas-fired post-combustion chambers operating at temperatures in excess of 1000 °C. A laboratory-scale flow reactor, using inductively coupled plasma, operating under sub-atmospheric conditions was developed. Fundamental experiments using model compounds have been performed, demonstrating a high destruction and removal ratio (>99.99%) for different reaction media, at low reactor temperatures and moderate power

  4. Evaluation of the thermal effect on separation selectivity in anion-exchange processes using superheated water ion-exchange chromatography.

    Science.gov (United States)

    Shibukawa, Masami; Taguchi, Akihiko; Suzuki, Yusuke; Saitoh, Kazunori; Hiaki, Toshihiko; Yarita, Takashi

    2012-07-07

    The thermal effect on retention and separation selectivity of inorganic anions and aromatic sulfonate ions in anion-exchange chromatography is studied on a quaternized styrene-divinylbenzene copolymer anion-exchange column in the temperature range of 40-120 °C using superheated water chromatography. The selectivity coefficient for a pair of identically charged anions approaches unity as temperature increases provided the ions have the same effective size, such that the retention of an analyte ion decreases with an increase in temperature when the analyte ion has stronger affinity for the ion-exchanger than that of the eluent counterion, whereas it increases when it has weaker affinity. The change in anion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions. At elevated temperatures, especially in superheated water, the electrostatic interaction or association of the ions with the fixed ion in the resin phase becomes a predominant factor resulting in a different separation selectivity from that obtained at ambient temperature.

  5. Comparison or organic and inorganic ion exchange materials for removal of cesium and strontium from Hanford waste

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.N.; Carson, K.J.; DesChane, J.R.; Elovich, R.J. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-10-01

    This work is part of an ESP-CP task to develop and evaluate high-capacity, selective, solid extractants for the uptake of cesium, strontium, and technetium (Cs, Sr, and Tc) from nuclear wastes. Pacific Northwest National Laboratory (PNNL) staff, in collaboration with researchers from industry, academia, and national laboratories are investigating these and other novel and commercial ion exchangers for use in nuclear waste remediation of groundwater, HLW, and LLW. Since FY 1995, experimental work at PNNL has focused on small-scale batch distribution (K{sub d}) testing of numerous solid sorbents with actual and simulated Hanford wastes, chemical and radiolytic stability of various organic ion exchanger resins, bench-scale column ion exchange testing in actual and simulated Complexant Concentrate (CC) and Neutralized Current Acid Waste (NCAW), and Tc and Sr removal from groundwater and LLW. In addition, PNNL has continued to support various site demonstrations at the Idaho National Engineering Laboratory, Savannah River Site, West Valley Nuclear Services, Hanford N-Springs, and Hanford N-Basin using technologies developed by their industrial partners. This summary will focus on batch distribution results from the actual waste tests. The data collected in these development and testing tasks provide a rational basis for the selection and direct comparison of various ion exchange materials in simulated and actual HLW, LLW, and groundwater. In addition, prediction of large-scale column loading performance for the materials tested is possible using smaller volumes of actual waste solution. The method maximizes information while minimizing experimental expense, time, and laboratory and process wastes.

  6. Modelling the ion-exchange equilibrium in nanoporous materials

    Directory of Open Access Journals (Sweden)

    M. Lukšič

    2012-06-01

    Full Text Available 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/CaCl2 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.

  7. Recovery of tetrachloroaurate through ion exchange with Dowex 11 resin

    Directory of Open Access Journals (Sweden)

    Alguacil, F. J.

    1998-05-01

    Full Text Available The recovery of the tetrachloroaurate complex by the anionic ion exchange resin Dowex 11 has been studied. The kinetics of gold adsorption were dependent of both gold and resin concentrations and temperature. The adsorption isotherm can be described by the expression Q = kCn. The loaded resin could be eluted by an acidic thiourea solution at 20°C. After several adsorption-elution cycles there is not any apparent loss in the adsorption properties of the resin.

    Se estudia la recuperación del ion tetracloroaurato mediante la resina aniónica Dowex 11. La extracción de oro depende tanto de las concentraciones del metal y la resina como de la temperatura. La isoterma de adsorción responde a la ecuación Q = kCn. La resina cargada con oro puede ser eluida con una disolución acida de tiourea a 20°C. Después de varios ciclos de adsorción-desorción no hay pérdida de carga por parte de la resina.

  8. Pretreatment/Radionuclide Separations of Cs/Tc from Supernates

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, M.C. [Westinghouse Savannah River Company, AIKEN, SC (United States)

    1998-09-01

    Significant improvements have been made in ion exchange and solvent extraction materials and processes available for separation of the radionuclides cesium and technetium from both acid and alkaline waste solutions. New ion exchange materials and solvent extraction reagents are more selective for Cs over sodium and potassium than previous materials. The higher selectivity gives higher Cs capacity and improved separation processes. Technetium removal has been improved by new ion exchange resins, which have either improved capacity or easier elution. Several different crown ethers have been shown to extract pertechnetate ion selectively over other anions. Organic complexants in some waste solutions reduce pertechnetate ion and stabilize the reduced species. Selective oxidation allows conversion to pertechnetate without oxidation of the organic complexants.

  9. Efficiency of Cs-free materials for negative ion production in H2 and D2 plasmas

    Science.gov (United States)

    Friedl, R.; Kurutz, U.; Fantz, U.

    2017-08-01

    High power negative ion sources use caesium to reduce the work function of the converter surface which significantly increases the negative ion yield. Caesium, however, is a very reactive alkali-metal and shows complex redistribution dynamics in consequence of plasma-surface-interaction. Thus, maintaining a stable and homogenous low work function surface is a demanding task, which is not easily compatible with the RAMI issues (reliability, availability, maintainability, inspectability) for a future DEMO fusion reactor. Hence, Cs-free alternative materials for efficient negative ion formation are desirable. At the laboratory experiment HOMER materials which are referred to as promising are investigated under identical and ion source relevant parameters: the refractory metals Ta and W, non-doped and boron-doped diamond as well as materials with inherent low work function (lanthanum-doped molybdenum, MoLa and lanthanum hexaboride, LaB6). The results are compared to the effect of in-situ caesiation, which at HOMER leads to a maximal increase of the negative ion density by a factor of 2.5. Among the examined samples low work function materials are most efficient. In particular, MoLa leads to an increase of almost 50 % compared to pure volume formation. The difference to a caesiated surface can be attributed to the still higher work function of MoLa, which is expected to be slightly below 3 eV. Using deuterium instead of hydrogen leads to increased atomic and positive ion densities, while comparable negative ion densities are achieved. In contrast to the low work function materials, bulk samples of the refractory metals as well as carbon based materials have no enhancing effect on H-, where the latter materials furthermore show severe erosion due to the hydrogen plasma.

  10. Er3+/Yb3+ Codoped Phosphate Glass for Ion-Exchanged Planar Waveguide Amplifiers

    Institute of Scientific and Technical Information of China (English)

    Shilong Zhao; Baoyu Chen; Zhuping Liu; Lili Hu

    2003-01-01

    A novel Er3+/Yb3+ codoped phosphate glass was developed, which exhibited good chemical durability in molten salts and excellent spectroscopic properties. Preliminary results of ion exchange at different time and temperature, and with varying melt concentrations indicated that WM4 glass was suitable for ion-exchange experiments and there was no deterioration of surface quality.

  11. Er~(3+)/Yb~(3+) Codoped Phosphate Glass for Ion-Exchanged Planar Waveguide Amplifiers

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel Er3+/Yb3+ codoped phosphate glass was developed, which exhibited good chemical durability in molten salts and excellent spectroscopic properties. Preliminary results of ion exchange at different time and temperature, and with varying melt concentrations indicated that WM4 glass was suitable for ion-exchange experiments and there was no deterioration of surface quality.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Selective ion exchange recovery of rare earth elements from uranium mining solutions

    Science.gov (United States)

    Rychkov, Vladimir N.; Kirillov, Evgeny V.; Kirillov, Sergey V.; Bunkov, Grigory M.; Mashkovtsev, Maxim A.; Botalov, Maxim S.; Semenishchev, Vladimir S.; Volkovich, Vladimir A.

    2016-09-01

    A comparative study of rare earth, ferric and aluminum ions ion exchange behavior on gel sulfonated p;olystyrene cation exchange resins depending on the degree of the matrix cross-linking and pH of the solution is presented. Selective ion exchange of REEs is possible at the pH range of 1.5-2.0 using strongly acidic cation exchange resins containing more than 8 % of DVB. The preliminary results of testing the efficiency of REEs recovery from the industrial uranium underground leaching solutions are also presented.

  14. Electrical Resistance and Transport Numbers of Ion-Exchange Membranes Used in Electrodialytic Soil Remediation

    DEFF Research Database (Denmark)

    Hansen, Henrik; Ottosen, Lisbeth M.; Villumsen, Arne

    1999-01-01

    causes damage to the membrane. This work presents the result from transport number and electrical resistance measurements done on four sets of ion-exchange membranes (Ionics, Inc. CR67 HMR412 cation-exchange membranes and Ionics, Inc. AR204 SXZR anion-exchange membranes), which have been used in four......Electrodialytic soil remediation is a recently developed method to decontaminate heavy metal polluted soil using ion-exchange membranes. In this method one side of the ion-exchange membrane is in direct contact with the polluted soil. It is of great importance to know if this contact with the soil...... different electrodialytic soil remediation experiments. The experiments showed that after the use in electrodialytic soil remediation, the ion-exchange membranes had transport numbers in the same magnitude as new membranes. The electrical resistance for six membranes did not differ from that of new...

  15. Nonlinear Inverse Problem for an Ion-Exchange Filter Model: Numerical Recovery of Parameters

    Directory of Open Access Journals (Sweden)

    Balgaisha Mukanova

    2015-01-01

    Full Text Available This paper considers the problem of identifying unknown parameters for a mathematical model of an ion-exchange filter via measurement at the outlet of the filter. The proposed mathematical model consists of a material balance equation, an equation describing the kinetics of ion-exchange for the nonequilibrium case, and an equation for the ion-exchange isotherm. The material balance equation includes a nonlinear term that depends on the kinetics of ion-exchange and several parameters. First, a numerical solution of the direct problem, the calculation of the impurities concentration at the outlet of the filter, is provided. Then, the inverse problem, finding the parameters of the ion-exchange process in nonequilibrium conditions, is formulated. A method for determining the approximate values of these parameters from the impurities concentration measured at the outlet of the filter is proposed.

  16. Low loss two-step ion-exchanged waveguides with high surface refractive index

    Science.gov (United States)

    Hassanzadeh, Abdollah; Mittler, Silvia

    2011-07-01

    Two-step ion-exchanged waveguides with high surface refractive indices are fabricated under a variety of conditions. By modifying the conventional two-step ion exchange, the losses and the effective diffusion depth can be decreased without a significant effect on the surface refractive index. The influence of the first step, K+-Na+ ion exchange, performed time dependably on the surface refractive index change is investigated. Energy-dispersive x-ray spectroscopy is performed to establish the diffusion profiles of various ions.

  17. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 1. Peptides to Proteins

    Science.gov (United States)

    Donohoe, Gregory C.; Khakinejad, Mahdiar; Valentine, Stephen J.

    2015-04-01

    Ion mobility spectrometry (IMS) coupled with hydrogen deuterium exchange (HDX)-mass spectrometry (MS) has been used to study the conformations of negatively-charged peptide and protein ions. Results are presented for ion conformers of angiotensin 1, a synthetic peptide (SP), bovine insulin, ubiquitin, and equine cytochrome c. In general, the SP ion conformers demonstrate a greater level of HDX efficiency as a greater proportion of the sites undergo HDX. Additionally, these ions exhibit the fastest rates of exchange. Comparatively, the angiotensin 1 ions exhibit a lower rate of exchange and HDX level presumably because of decreased accessibility of exchange sites by charge sites. The latter are likely confined to the peptide termini. Insulin ions show dramatically reduced HDX levels and exchange rates, which can be attributed to decreased conformational flexibility resulting from the disulfide bonds. For the larger ubiquitin and protein ions, increased HDX is observed for larger ions of higher charge state. For ubiquitin, a conformational transition from compact to more elongated species (from lower to higher charge states) is reflected by an increase in HDX levels. These results can be explained by a combination of interior site protection by compact conformers as well as decreased access by charge sites. The elongated cytochrome c ions provide the largest HDX levels where higher values correlate with charge state. These results are consistent with increased exchange site accessibility by additional charge sites. The data from these enhanced IMS-HDX experiments are described in terms of charge site location, conformer rigidity, and interior site protection.

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

    Science.gov (United States)

    Khokhlova, O. N.

    2014-08-01

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

  19. Overloading ion-exchange membranes as a purification step for monoclonal antibodies

    OpenAIRE

    Brown, Arick; Bill, Jerome; Tully, Timothy; Radhamohan, Asha; Dowd, Chris

    2010-01-01

    The present study examined the overloading of ion-exchange membrane adsorbers, a form of frontal chromatography, as the final purification step in the production of mAbs (monoclonal antibodies) produced from CHO (Chinese-hamster ovary) cells. Preferential binding of impurities over antibody product was exploited using commercially available cation- and anion-exchange membranes. Three different antibody feedstreams previously purified over Protein A and ion-exchange column chromatography were ...

  20. Revised Thermal Analysis of LANL Ion Exchange Column

    Energy Technology Data Exchange (ETDEWEB)

    Laurinat, J

    2006-04-11

    This document updates a previous calculation of the temperature distributions in a Los Alamos National Laboratory (LANL) ion exchange column.1 LANL operates two laboratory-scale anion exchange columns, in series, to extract Pu-238 from nitric acid solutions. The Defense Nuclear Facilities Safety Board has requested an updated analysis to calculate maximum temperatures for higher resin loading capacities obtained with a new formulation of the Reillex HPQ anion exchange resin. The increased resin loading capacity will not exceed 118 g plutonium per L of resin bed. Calculations were requested for normal operation of the resin bed at the minimum allowable solution feed rate of 30 mL/min and after an interruption of flow at the end of the feed stage, when one of the columns is fully loaded. 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. At low temperatures, resin bed temperatures increase primarily due to decay heat. At {approx}70 C a Low Temperature Exotherm (LTE) resulting from the reaction between 8-12 M HNO{sub 3} and the resin has been observed. The LTE has been attributed to an irreversible oxidation of pendant ethyl benzene groups at the termini of the resin polymer chains by nitric acid. The ethyl benzene groups are converted to benzoic acid moities. The resin can be treated to permanently remove the LTE by heating a resin suspension in 8M HNO{sub 3} for 30-45 minutes. No degradation of the resin performance is observed after the LTE removal treatment. In fact, heating the resin in boiling ({approx}115-120 C) 12 M HNO{sub 3} for 3 hr displays thermal stability analogous to resin that has been treated to remove the LTE. The analysis is based on a previous study of the SRS Frames Waste Recovery (FWR) column, performed in support of the Pu-238 production campaign for NASA's Cassini mission. In that study, temperature transients

  1. Praseodymium ion doped phosphate glasses for integrated broadband ion-exchanged waveguide amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Shen, L.F. [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Chen, B.J. [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Lin, H., E-mail: lhai8686@yahoo.com [School of Textile and Material Engineering, Dalian Polytechnic University, Dalian 116034 (China); Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Pun, E.Y.B. [Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)

    2015-02-15

    Highlights: • Effective near-infrared emission (1380-1525 nm) is observed in Pr{sup 3+}-doped phosphate glasses. • Effective bandwidth of {sup 1}D{sub 2} → {sup 1}G{sub 4} transition emission is obtained to be 124 nm. • Channel waveguides have been fabricated by K{sup +}-Na{sup +} ion-exchange method. • Pr{sup 3+}-doped phosphate glasses are promising in developing integrated broadband waveguide amplifier. - Abstract: Effective near-infrared emission covering the fifth optical telecommunication window (1380-1525 nm) has been observed in Pr{sup 3+}-doped phosphate (NMAP) glasses. Judd-Ofelt parameters Ω{sub 2} (6.38 × 10{sup −20} cm{sup 2}), Ω{sub 4} (20.30 × 10{sup −20} cm{sup 2}) and Ω{sub 6} (0.40 × 10{sup −20} cm{sup 2}) indicate a high inversion asymmetrical and strong covalent environment in the optical glasses. The effective bandwidth (Δλ{sub eff}) of the corresponding {sup 1}D{sub 2} → {sup 1}G{sub 4} transition emission is obtained to be 124 nm, and the maximum stimulated emission cross-section (σ{sub em-max}) at 1468 nm is derived to be 1.14 × 10{sup −20} cm{sup 2}. Channel waveguide was fabricated successfully by K{sup +}-Na{sup +} ion-exchange method with mode field diameter of 8.8 μm in the horizontal direction and 6.7 μm in the vertical direction. Broad effective bandwidth, large emission cross-section and perfect thermal ion-exchangeability indicate that Pr{sup 3+}-doped NMAP phosphate glasses are promising in developing integrated broadband waveguide amplifier, especially operating at E- and S-bands which belong to the fifth optical telecommunication window.

  2. Adsorption Characteristics of Ion-Exchanged ZSM-5 Zeolites for CO(2)/N(2) Mixtures.

    Science.gov (United States)

    Katoh, Masahiro; Yoshikawa, Takushi; Tomonari, Takao; Katayama, Kazuyuki; Tomida, Tahei

    2000-06-01

    Adsorption characteristics of alkali metal ion-exchanged ZSM-5 zeolites, M-ZSM-5 (M=Li, Na, K, Rb, and Cs), for CO(2)/N(2) mixtures were investigated by a column method and IR study. It was shown that CO(2) was adsorbed from CO(2)/N(2) mixtures on M-ZSM-5 zeolites by two types of adsorbtion at temperatures below 333 K. One was a weak adsorption due to interaction with the wall of ZSM-5, and the other was a strong adsorption caused by interactions with the cation of ZSM-5. IR-spectra of gases adsorbed at various temperatures revealed that the CO(2) were strongly adsorbed on M-ZSM-5 in several ways, which seemed to be caused by different adsorption sites. At temperatures above 373 K, almost all CO(2) adsorbed were on cation sites, while N(2) coadsorbed with CO(2) was shown to interact with the wall of ZSM-5 under all experimental conditions. Copyright 2000 Academic Press.

  3. Combination of Metal Coordination Tetrahedra and Asymmetric Coordination Geometries of Sb(III) in the Organically Directed Chalcogenidometalates: Structural Diversity and Ion-exchange Properties.

    Science.gov (United States)

    Feng, Mei-Ling; Wang, Kai-Yao; Huang, Xiao-Ying

    2016-04-01

    Chalcogenidometalates exhibit rich and diverse structures and properties applicable to ion exchange, thermoelectrics, photocatalysis, nonlinear optics, and so on. This personal account summarizes our recent progress in constructing chalcogenidometalates by combining metal coordination tetrahedra and the asymmetric coordination geometries of Sb(3+) in the presence of organic species (typically organic amines and metal-organic amine complexes), which has been demonstrated as an effective strategy for synthesizing chalcogenidometalates with diversified structures and interesting properties. The linkage modes of asymmetric SbQn (n = 3, 4) geometries and group 13 (or 14) metal coordination tetrahedra are analyzed, and the secondary building units (SBUs), with different compositions and architectures, are clarified. The crucial role and function of organic species in the formation of chalcogenidometalates are explored, with an emphasis on their powerful structure-directing features. In particular, some chalcogenidometalates in this family exhibit excellent ion-exchange properties for Cs(+) and/or Sr(2+) ions; the factors affecting ion-exchange properties are discussed to understand the underlying ion-exchange mechanism.

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

    Science.gov (United States)

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

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

  5. Stabilization of Metal-Loaded Ion-Exchange Resin with a Porous Silica Supporter Through Thermal Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, I-T. Park, H-S.; Yoo, J-H.; Kim, J-H.

    2003-02-25

    A new ion exchanger with porous silica as a supporting material and diphosphonic acid as a functional chelating group has been developed at ANL for the effective removal of transition metals and actinide ions from very acidic radioactive liquid wastes. The applicability of this resin for the treatment of low- and/or intermediate-level aqueous waste from nuclear power plants (NPP) has not been reported in scientific literature, but is under study now in Korea. The major radioisotopes in NPP radioactive liquid waste are Cs and Co in neutral pH ranges. This study on the thermal stabilization of metal-loaded waste resin has been carried out in parallel with the sorption experiment. Thermal treatment of metal (Co, Cs or U) loaded resin was accomplished to see the possibility of enhancing the safety and stability of the final product during transportation and disposal. In this paper, characteristics of the metal-loaded resins before and after heat treatment at three different thermal conditions were investigated and compared with each other to see the effectiveness of the thermal treatment method.

  6. New Inorganic Ion-exchange Material for the Selective Removal of Fluoride from Potable Water Using Ion-selective Electrode

    Directory of Open Access Journals (Sweden)

    Rasheed M.A.Q. Jamhour

    2005-01-01

    Full Text Available An ion-exchange procedure involving the selective retention of fluoride ions from aqueous solutions containing 1, 5, 10, 20 and 50 mg F- L-1 using a new inorganic ion exchanger zirconium(IV oxide-ethanolamine ZrO-EA and its application to fluoride removal from potable water has been described. A column equilibrium studies, batch process and different analytical parameters such as concentration, pH and temperature for the quantitative recoveries of F- ion using ZrO-EA exchanger were investigated and determined by an ion selective electrode. The effect of some other anions that might be present with the analyte was also examined. The column experiments showed a quantitative collection of fluoride at low concentration in water samples with more than 96% recovery.

  7. A new fluorescent film sensor for Pb(II) ions developed by simulating bio-mineralization process synthesizing of ZnS/CS nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Wang Shan, E-mail: shanwang2005@163.com [School of Chemistry and Chemical Engineering, Xianyang Normal University, Xianyang, 712000, Shaanxi Province (China) and Department of Applied Chemistry, Xi' an Jiaotong University, Xi' an, 710049, Shaanxi Province (China); Yu Demei; Wu Guangwen [Department of Applied Chemistry, Xi' an Jiaotong University, Xi' an, 710049, Shaanxi Province (China); Guo Jinchan; Lei Cao [School of Chemistry and Chemical Engineering, Xianyang Normal University, Xianyang, 712000, Shaanxi Province (China)

    2011-07-25

    Highlights: > Chitosan/zinc sulfide (CS/ZnS) nano-composite films have been prepared by simulating bio-mineralization process.the sensing properties of nano-composite films to lead ions have been systematically investigated. > SEM and TEM observations showed that the size of ZnS particles in the CS films. > The fluorescence emission of the nanocomposite films is very sensitive to the presence of Pb ions and the emission is hardly affected by common ions in water, except for the iron ions. > The films may be developed as excellent sensing films for Pb ions in water. - Abstract: Chitosan/zinc sulfide (CS/ZnS) nano-composite films have been prepared by simulating bio-mineralization process. Factors affecting the hydrothermal stability and fluorescence properties of the films have been studied. Furthermore, the sensing properties of nano-composite films to lead ions have been systematically investigated. SEM and TEM observations showed that the size of ZnS particles is 70 nm, and the particles are evenly distributed within the CS films. The fluorescence emission of the nano-composite films indicates that the sizes of real fluorescing ZnS particles are less than 20 nm. This suggests that ZnS particles observed via SEM and TEM may be aggregates of smaller ZnS particles, and the smaller particles may be separated by the organics. The fluorescence emission (363 nm) of the nano-composite films is very sensitive to the presence of Pb ions. C{sub (Pb}{sup 2+}{sub )} increased from 0 to 664.2 mg L{sup -1} increases the emission dramatically. The emission is hardly affected by common ions in water, except for the iron ions. The films may be developed as excellent sensing films for Pb ions in water.

  8. Crystalline Silicotitanate Ion Exchange Support for Salt-Alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Fondeur, F.F.

    2001-02-23

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

  9. Porous metal oxide microspheres from ion exchange resin

    Science.gov (United States)

    Picart, S.; Parant, P.; Caisso, M.; Remy, E.; Mokhtari, H.; Jobelin, I.; Bayle, J. P.; Martin, C. L.; Blanchart, P.; Ayral, A.; Delahaye, T.

    2015-07-01

    This study is devoted to the synthesis and the characterization of porous metal oxide microsphere from metal loaded ion exchange resin. Their application concerns the fabrication of uranium-americium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Those mixed oxide ceramics are one of the materials envisaged for americium transmutation in sodium fast neutron reactors. The advantage of such microsphere precursor compared to classical oxide powder is the diminution of the risk of fine dissemination which can be critical for the handling of highly radioactive powders such as americium based oxides and the improvement of flowability for the filling of compaction chamber. Those millimetric oxide microspheres incorporating uranium and americium were synthesized and characterizations showed a very porous microstructure very brittle in nature which occurred to be adapted to shaping by compaction. Studies allowed to determine an optimal heat treatment with calcination temperature comprised between 700-800 °C and temperature rate lower than 2 °C/min. Oxide Precursors were die-pressed into pellets and then sintered under air to form regular ceramic pellets of 95% of theoretical density (TD) and of homogeneous microstructure. This study validated thus the scientific feasibility of the CRMP process to prepare bearing americium target in a powder free manner.

  10. Protein-surface interaction maps for ion-exchange chromatography.

    Science.gov (United States)

    Freed, Alexander S; Cramer, Steven M

    2011-04-05

    In this paper, protein-surface interaction maps were generated by performing coarse-grained protein-surface calculations. This approach allowed for the rapid determination of the protein-surface interaction energies at a range of orientations and distances. Interaction maps of lysozyme indicated that there was a contiguous series of orientations corresponding to several adjacent preferred binding regions on the protein surface. Examination of these orientations provided insight into the residues involved in surface interactions, which qualitatively agreed with the retention data for single-site mutants. Interaction maps of lysozyme single-site mutants were also generated and provided significant insight into why these variants exhibited significant differences in their chromatographic behavior. This approach was also employed to study the binding behavior of CspB and related mutants. The results indicated that, in addition to describing general trends in the data, these maps provided significant insight into retention data of the single-site mutants. In particular, subtle retention trends observed with the K12 and K13 mutants were well-described using this interaction map approach. Finally, the number of interaction points with energies stronger than -2 kcal/mol was shown to be able to semi-quantitatively predict the behavior of most of the mutants. This rapid approach for calculating protein-surface interaction maps is expected to facilitate future method development for separating closely related protein variants in ion-exchange systems.

  11. Ion-exchange chromatography for the characterization of biopharmaceuticals.

    Science.gov (United States)

    Fekete, Szabolcs; Beck, Alain; Veuthey, Jean-Luc; Guillarme, Davy

    2015-09-10

    Ion-exchange chromatography (IEX) is a historical technique widely used for the detailed characterization of therapeutic proteins and can be considered as a reference and powerful technique for the qualitative and quantitative evaluation of charge heterogeneity. The goal of this review is to provide an overview of theoretical and practical aspects of modern IEX applied for the characterization of therapeutic proteins including monoclonal antibodies (Mabs) and antibody drug conjugates (ADCs). The section on method development describes how to select a suitable stationary phase chemistry and dimensions, the mobile phase conditions (pH, nature and concentration of salt), as well as the temperature and flow rate, considering proteins isoelectric point (pI). In addition, both salt-gradient and pH-gradient approaches were critically reviewed and benefits as well as limitations of these two strategies were provided. Finally, several applications, mostly from pharmaceutical industries, illustrate the potential of IEX for the characterization of charge variants of various types of biopharmaceutical products.

  12. The heats of exchange of transition metal ions on the Na form of clinoptilolite

    Science.gov (United States)

    Tarasevich, Yu. I.; Krysenko, D. A.; Polyakov, V. E.; Aksenenko, E. V.

    2008-09-01

    Direct calorimetric measurements were used to determine the heats of exchange of the Mn2+, Co2+, Cu2+, and Ni2+ cations on the Na form of clinoptilolite over the entire range of solid phase fillings with sorbed cations. In parallel, ion exchange isotherms for the systems were measured by the sorption-analytic method. The integral free energies and entropies of ion exchange were calculated. It was shown that the solution phase of the clinoptilolite-electrolyte solution two-phase system contributed significantly to the total thermodynamic characteristics of ion exchange. The differentiation of the dependence of the integral enthalpy on the degree of filling was performed to show that the clinoptilolite structure contained at least two types of exchange sites having different interaction energies with transition metal ions.

  13. Preparation and characterization of polysulfone/PEG heterogeneous ion exchange membrane for reverse electrodialysis (RED)

    Science.gov (United States)

    Ariono, D.; Khoiruddin; Prabandari, D.; Wulandari, R.; Wenten, I. G.

    2017-07-01

    Heterogeneous cation-exchange membrane is synthesized using solution casting method. The casting solution is prepared by dispersing finely ground cation-exchange resin particles in N,N-dimethylacetamide (DMAc) solutions of polysulfone (PSf) while polyethylene glycol (PEG400) is used as a modifier. The results show that the PEG400 can increase water uptake, conductivity, and ion-exchange capacity (IEC) of the heterogeneous cation-exchange membrane due to the hydrophilic nature of PEG400. The more hydrophilic membrane results in higher water uptake and wider access for functional sites. However, when the concentration of PEG400 is increased further, the IEC and conductivity tend to decrease. This tendency is more pronounced when the ion-exchange resin particle is increased from 50 to 60%-wt. It could be attributed to the washed out of some ion-exchange particle during membrane immersion due to lower bonding between membrane matrix and the particles.

  14. Modeling cesium ion exchange on fixed-bed columns of crystalline silicotitanate granules

    Energy Technology Data Exchange (ETDEWEB)

    Latheef, I.M.; Huckman, M.E.; Anthony, R.G.

    2000-05-01

    A mathematical model is presented to simulate Cs exchange in fixed-bed columns of a novel crystalline silicotitanate (CST) material, UOP IONSIV IE-911. A local equilibrium is assumed between the macropores and the solid crystals for the particle material balance. Axial dispersed flow and film mass-transfer resistance are incorporated into the column model. Cs equilibrium isotherms and diffusion coefficients were measured experimentally, and dispersion and film mass-transfer coefficients were estimated from correlations. Cs exchange column experiments were conducted in 5--5.7 M Na solutions and simulated using the proposed model. Best-fit diffusion coefficients from column simulations were compared with previously reported batch values of Gu et al. and Huckman. Cs diffusion coefficients for the column were between 2.5 and 5.0 x 10{sup {minus}11} m{sup 2}/s for 5--5.7 M Na solutions. The effect of the isotherm shape on the Cs diffusion coefficient was investigated. The proposed model provides good fits to experimental data and may be utilized in designing commercial-scale units.

  15. Preparation, Characterization and Catalytic Behavior of 12-Molybdophosphoric Acid Encapsulated in the Supercage of Cs+-exchanged Y Zeolite%Cs交换Y沸石超笼中的磷钼杂多酸的制备、表征和催化性能

    Institute of Scientific and Technical Information of China (English)

    魏瑞平; 郭麦平; 王军

    2009-01-01

    In order to solve the serious leaching problem of supported heteropoly acid catalysts in polar reaction media, 12-molybdophosphoric acid encapsulated in the supercage of Cs+-exchanged Y zeolite was prepared by the"ship in the bottle" synthesis. The influence of ion-exchange conditions and the synthesis parameters on the encapsulation of PMo12 were investigated. The obtained solid sample was characterized by X-ray diffraction (XRD), 31pmagic angle spin nuclear magnetic resonance (MAS NMR) and Fourier Transform Infrared Spectroscopy (FT-IR), and its catalytic activity in the esterification of acetic acid and n-butanol was tested. The ion-exchange time, concentration of aqueous Cs+ solution, pH value, and amount of Mo added in the synthesis mixture were revealed to influence the encapsulation very remarkably. Under the optimal conditions, 12-molybdophosphoric acid could be successfully encapsulated in the supercage of CsY zeolite, and the samples showed considerable catalytic activity and excellent reusability in the esterification reaction.

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

    Science.gov (United States)

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

    2005-08-02

    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.

  17. On-line coupling of an ion chromatograph to the ICP-MS: Separations with a cation exchange chromatography column

    Energy Technology Data Exchange (ETDEWEB)

    Roellin, Stefan [Studsvik Nuclear AB, Nykoeping (Sweden)

    1999-12-01

    An ion chromatography system was coupled on-line to the ICP-MS. All separations were made with a cation exchange chromatography column. Fundamental laws about elution parameters affecting individual retention times and elution forms are explained by applying a proper ion exchange mechanism for the isocratic elution (separations with constant eluent concentration) of mono-, di-, tri-, and tetravalent cations and the actinide species MO{sub 2}{sup +} and MO{sub 2}{sup 2+}. A separation method with two eluents has been investigated to separate mono- from divalent ions in order to separate isobaric overlaps of Rb/Sr and Cs/Ba. The ions normally formed by actinides in aqueous solutions in the oxidation states III to VI are M{sup 3+}, M{sup 4+}, MO{sub 2}{sup +} and MO{sub 2}{sup 2+} respectively. Elution parameters were investigated to separate all four actinide species from each other in order to separate isobaric overlaps of the actinides Np, Pu, U and Am. A major question of concern over the possible release of actinides to the environment is the speciation of actinides within their four possible oxidation states. To check the possibility of speciation analysis with ion chromatography, a separation method was investigated to separate U{sup 4+} and UO{sub 2}{sup 2+} without changing the redox species composition during the separation. First results of Pu speciation analysis showed that Pu could be eluted as three different species. Pu(VI) was always eluting at the same time as Np(V). This was surprising as Pu(VI) is expected to have the same chemical characteristics as U(VI) and thus was expected to elute at the same time as U(VI)

  18. A comparative study of ion exchange kinetics in zinc/lead-modified zeolite-clinoptilolite systems.

    Science.gov (United States)

    Trgo, M; Perić, J; Medvidović, N Vukojević

    2006-08-25

    The kinetics of zinc and lead ions removal by modified zeolite-clinoptilolite has been investigated. The rate of the ion exchange process for lead ions is faster than for zinc ions, as well as the time needed to reach the equilibrium. The ion exchange capacity of zeolite of lead ions is doubly higher than that of zinc ions. Diffusion models according to the Vermeulen's approximation, the parabolic diffusion model and the homogeneous diffusion model have been tested with the experimental data of ion exchange for zinc and lead. For both systems examined, the best fit of the models proposed with the experimental data was shown by the Vermeulen's approximation and the homogeneous diffusion model with t-->t(infinity). The diffusion coefficients are calculated from kinetic models of lead ions they are of the order of 10(-6)cm(2)/min, constant for all examined initial concentrations and not dependent on time. The diffusion coefficients in the system of zinc ions is of the order of 10(-8)cm(2)/min, also independent of initial concentrations, but decreasing with time from the beginning of ion exchange to the equilibrium.

  19. Electrospun Zeolite/Cellulose Acetate Fibers for Ion Exchange of Pb2+

    Directory of Open Access Journals (Sweden)

    Daniel N. Tran

    2014-12-01

    Full Text Available The ion exchange capability of electrospun cellulose acetate (CA fibers containing zeolite A nanoparticles is reported. Solid and porous CA fibers were used to make a zeolite-embedded filter paper, which was then used to ion exchange Na+ with Cu2+ and Pb2+. The composite Linde Type A (LTA zeolite CA fibers exchanged 0.39 mmol/g more Pb2+ than LTA nanoparticles in the solid CA fibers. These fibers could provide a simple and effective method for heavy metal ion removal in water.

  20. Analyzing the effect of ion exchange on flexural strength of cermaco II and colorlogic veneer porcelains

    Directory of Open Access Journals (Sweden)

    N. Rashidan

    1998-04-01

    Full Text Available   The major foible of dental ceramics is their brittle nature. Therefore, the producers of these materials have focused on the “strength” issue. A method of increasing strength is ion exchange on porcelain surface which leads to formation of a compressive crust that opposing forces should overcome before developing a crack. In current study, ion exchange in two types of porcelain, Ceramco II which is used in PFM restorations and Colorloic veneer which is used for laminates, veneers, inlays and onlays, are evaluated. Additionally, laminate porcelains, etching effect on strength of porcelain and interaction of acid etching and ion exchange have been studied.

  1. Mixed ion exchange supports as useful ion exchangers for protein purification: purification of penicillin G acylase from Escherichia coli.

    Science.gov (United States)

    Fuentes, Manuel; Batalla, Pilar; Grazu, Valeria; Pessela, Benevides C C; Mateo, Cesar; Montes, Tamara; Hermoso, Juan A; Guisan, Jose M; Fernandez-Lafuente, Roberto

    2007-02-01

    A support having similar amounts of carboxymethyl and amino groups has been prepared and evaluated as an ion exchanger. It has been found that this support was able to adsorb a high amount of protein from a crude extract of proteins (approximately 55%) at pH 5. Moreover, it was able to adsorb approximately 60% of the protein that did not become adsorbed on supports bearing just one kind of ionic groups. The use of divalent cations reinforced the adsorption of proteins on these supports. These results suggest that the adsorption of proteins on supports bearing almost neutral charge is not driven by the existence of opposite charges between the adsorbent and the biomacromolecule but just by the possibility of forming a high number of enzyme-support ionic bonds. This support has been used to purify the enzyme penicillin G acylase (PGA) from Escherichia coli. PGA was not significantly adsorbed at any pH value on either amino- or carboxyl-activated supports, while it can be fully adsorbed at pH 5 on this new carboxyl-amino matrix. Thus, we have been able to almost fully purify PGA from crude extracts with a very high yield by using these new supports.

  2. Zero-field splitting and local structure for V2+ ions in CsMgX$_{3} (X=Cl, Br, I)$ crystals

    Indian Academy of Sciences (India)

    Q Wei; Q M Xu; Z Y Yang; D Y Zhang; J G Zhang

    2009-11-01

    The zero-field splitting and local structure for V2+ ions in CsMgX3 $(X = Cl, Br, I)$ crystals are theoretically investigated using complete diagonalization method (CDM) for a $3d^{3}$ ion in trigonal symmetry. Spin–spin (SS) and spin–other-orbit (SOO) interactions are taken into account in addition to the general spin–orbit (SO) interaction. On this basis, using ligand ion displacement model, we find that the ligand ions move away from $C_{3}$-axis, and therefore the local angles in the $V^{2+}$ centres are larger than the angles in the hosts. The results show good agreement with the observed values.

  3. CW/Pulsed H- ion beam generation with PKU Cs-free 2.45 GHz microwave driven ion source

    Science.gov (United States)

    Peng, S. X.; Ren, H. T.; Xu, Y.; Zhang, T.; Zhang, A. L.; Zhang, J. F.; Zhao, J.; Guo, Z. Y.; Chen, J. E.

    2015-04-01

    Circular accelerators used for positron emission tomography (PET, i.e. accelerator used for make radio isotopes) need several mA of CW H- ion beam for their routine operation. Other facilities, like Space Radio-Environment Simulate Assembly (SPRESA), require less than 10 mA pulsed mode H- beam. Caesium free negative hydrogen ion source is a good choice for those facilities because of its compact structure, easy operation and low cost. Up to now, there is no H- source able to produce very intense H- beams with important variation of the duty factor[1]. Recently, a new version of 2.45 GHz microwave H- ion source was designed at PKU, based on lessons learnt from the previous one. This non cesiated source is very compact thanks to its permanent magnet configuration. Special attention was paid on the design of the discharge chamber structure, electron dumping and extraction system. Source test to produce H- ion beams in pulsed and CW mode was carried out on PKU ion source test bench. In CW mode, a 10.8 mA/30keV H- beam with rms emittance about 0.16 π.mm.mrad has been obtained with only 500 W rf power. The power efficiency reaches 21 mA/kW. In pulsed mode with duty factor of 10% (100Hz/1ms), this compact source can easily deliver 20 mA H- ion beam at 35 keV with rms emittance about 0.2 π.mm.mrad when RF power is set at 2.2 kW (peak power). Several hour successive running operation in both modes and totaling more than 200 hours proves its high quality. The outside dimension of this new H- source body is ϕ116 mm × 124 mm, and the entire H- source infrastructure, including rf matching section, plasma chamber and extraction system, is ϕ310 × 180 mm. The high voltage region is limited with in a ϕ310 mm × 230 mm diagram. Details are given in this paper.

  4. Quantitative Analysis of Water Confined in Ion-Exchanged Zeolites

    Science.gov (United States)

    Wang, J.; Neuhoff, P. S.

    2009-12-01

    Zeolites, which host large quantities of water, are among the most important rock-forming and environmental minerals in the surface and near-surface regions of the Earth. The physical properties and geochemical behavior of water confined in zeolites differs substantially from that of bulk liquid water, and the energectics of confined water exerts a profound influence on the stability and behavior of zeolites in natural and engineered systems. Because the cations and water molecules are both located in the zeolitic channels, changes in cation content can influence the amount and site occupancies of water molecules in zeolites. In order to find out the relationship between the behavior of confined water and cation composition in zeolites, thermogravimetric and calorimetric experiments were conducted on the mordenite (one of the most common zeolites) samples of mixing Na+ and K+. These mordenite solid solutions were generated by binary ion exchange between pure synthetic Na-mordenite (CBV 10A, obtained from Zeolyst International) and chloride solutions containing Na+ and K+ of different equivalent concentration ratios. The results from dehydration and hydration of the mordenite solid solutions show that when the mole fraction of K+ in mordenite increases, the maximum water content of mordenite decreases and the enthalpy of hydration becomes less exothermic. More importantly, both maximum water content and enthalpy of hydration of mordenite are demonstrated to change linearly with mole fraction of K+. Two energetically distinct sets of water molecules have been observed in mordenite: W1 (relatively less energetic) and W2 (relatively high energetic). Thermodynamic analysis on the hydration of W1 and W2 reveals that these two sets of water molecules behave differently when cation composition of mordenite changes. The water content of W2 is independent of cation composition, whereas W1 loses water with when mole fraction of K+ increases; the enthalpy of hydration of W1

  5. Characteristics of cesium ion sorption from aqueous solution on bentonite- and carbon nanotube-based composites

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shubin [Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561 (Japan); Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Han, Cho [Graduate School of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan); Wang, Xiangke [Key Laboratory of Novel Thin Film Solar Cells, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Faculty of Engineering, King Abdulaziz University, Jeddah 21589 (Saudi Arabia); Nagatsu, Masaaki, E-mail: tmnagat@ipc.shizuoka.ac.jp [Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561 (Japan); Graduate School of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan)

    2014-06-01

    Highlights: • The effects of cation and hydroxyl exchanges on Cs{sup +} sorption are investigated. • The CS-g-CNTs and the CS-g-bentonite composites are designed. • The effect of different cations on Cs{sup +} adsorption is detected. • The cation-exchange is much more effective in Cs{sup +} sorption than the hydroxyl group. • We give the future directions of new and selective adsorbents for Cs{sup +} ions. - Abstract: The technology development of Cs{sup +} capture from aqueous solution is crucial for the disposal of nuclear waste and still remains a significant challenge. Previous researches have been proven that ion exchanges with the cations and hydroxyl exchange are the main sorption mechanisms for Cs{sup +}. Therefore, how important are the cation exchange and the hydroxyl exchange mechanisms to Cs{sup +} sorption? And whether can we improve the sorption capacity of the material by increasing the amount of hydroxyl groups? With these in mind, we herein designed the chitosan-grafted carbon nanotubes (CS-g-CNTs) and the chitosan-grafted bentonite (CS-g-bentonite) by plasma-induced grafting method. The interactions of Cs{sup +} with CNTs, bentonite, CS-g-CNTs and CS-g-bentonite composites were investigated. The sorption of Cs{sup +} is mainly dominated by strong cation exchange in monovalent Group I and divalent Group II. And the cation-exchange mechanism is much more effective than the hydroxyl group exchange. The effect of hydroxyl groups is dependent on the property of the matrix. We cannot improve the Cs adsorption capacity of material for Cs{sup +} only by increasing the amount of hydroxyl groups in any case. The spatial structure and the cation-exchange capacity of the material are important factors for choosing the sorbent for Cs{sup +} removal from radioactive waste water.

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

    Directory of Open Access Journals (Sweden)

    Marta Miola

    2016-05-01

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

  7. Enhanced capacity and stability for the separation of cesium in electrically switched ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Tawfic, A.F.; Dickson, S.E.; Kim, Y. [McMaster University, Hamilton, ON (Canada); Mekky, W. [AMEC NSS, Power and Process America, Toronto (Canada)

    2015-03-15

    Electrically switched ion exchange (ESIX) can be used to separate ionic contaminants from industrial wastewater, including that generated by the nuclear industry. The ESIX method involves sequential application of reduction and oxidation potentials to an ion exchange film to induce the respective loading and unloading of cesium. This technology is superior to conventional methods (e.g electrodialysis reversal or reverse osmosis) as it requires very little energy for ionic separation. In previous studies, ESIX films have demonstrated relatively low ion exchange capacities and limited film stabilities over repeated potential applications. In this study, the methodology for the deposition of electro-active films (nickel hexacyanoferrate) on nickel electrodes was modified to improve the ion exchange capacity for cesium removal using ESIX. Cyclic voltammetry was used to investigate the ion exchange capacity and stability. Scanning electron microscopy (SEM) was used to characterize the modified film surfaces. Additionally, the films were examined for the separation of cesium ions. This modified film preparation technique enhanced the ion exchange capacity and improves the film stability compared to previous methods for the deposition of ESIX films. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  9. DEVELOPMENT OF AN APPROACH TO MODELING LOADING AND ELUTION OF SPHERICAL RESORCINOL FORMALDEHYDE ION-EXCHANGE RESIN

    Energy Technology Data Exchange (ETDEWEB)

    Aleman, S.; Hamm, L.; Smith, F.

    2011-10-03

    The current strategy for removal of cesium from the Hanford waste stream is ion-exchange using spherical Resorcinol-Formaldehyde (sRF) resin. The original resin of choice was granular SuperLig 644 resin and during testing of this resin several operational issues were identified. For example, the granular material had a high angle of internal friction resulting in fragmentation of resin particles along its edges during cycling and adverse hydraulic performance. Efforts to replace SuperLig 644 were undertaken and one candidate was the granular Resorcinol-Formaldehyde (RF) resin where experience with this cation exchanger dates back to the late 1940's. To minimize hydraulic concerns a spherical version of RF was developed and several different chemically produced batches were created. The 5E-370/641 batch of sRF was selected and for the last decade numerous studies have been performed (e.g., batch contact tests, column loading and elution tests). The Waste Treatment Plant (WTP) flowsheet shows that the aqueous phase waste stream will have a wide range of ionic concentrations (e.g., during the loading step 0-3 M free OH, 5+ M Na, 0-1 M K, 0-3 M NO{sub 3}). Several steps are required in the ion-exchange process to achieve the required Cs separation factors: loading, displacement, washing, elution, and regeneration. The sRF resin will be operated over a wide range in pH (i.e., pH of 12-14 during the loading step and pH of 0.01-1 during the elution step). During some of these steps very high levels of counter-ions and co-ions will be present within the aqueous phase. Alternative process feeds are under consideration as well (e.g., sodium levels as high as 8 M and column operation up to 45 C during loading, reduced and recycled HNO{sub 3} during elution). In order to model the performance of sRF resin through an entire ion-exchange cycle, a more robust isotherm model is required. To achieve this more robust isotherm model requires knowledge of the numbers and kinds of

  10. Tuning a High Transmission Ion Guide to Prevent Gas-Phase Proton Exchange During H/D Exchange MS Analysis.

    Science.gov (United States)

    Guttman, Miklos; Wales, Thomas E; Whittington, Dale; Engen, John R; Brown, Jeffery M; Lee, Kelly K

    2016-04-01

    Hydrogen/deuterium exchange (HDX) mass spectrometry (MS) for protein structural analysis has been adopted for many purposes, including biopharmaceutical development. One of the benefits of examining amide proton exchange by mass spectrometry is that it can readily resolve different exchange regimes, as evidenced by either binomial or bimodal isotope patterns. By careful analysis of the isotope pattern during exchange, more insight can be obtained on protein behavior in solution. However, one must be sure that any observed bimodal isotope patterns are not artifacts of analysis and are reflective of the true behavior in solution. Sample carryover and certain stationary phases are known as potential sources of bimodal artifacts. Here, we describe an additional undocumented source of deuterium loss resulting in artificial bimodal patterns for certain highly charged peptides. We demonstrate that this phenomenon is predominantly due to gas-phase proton exchange between peptides and bulk solvent within the initial stages of high-transmission conjoined ion guides. Minor adjustments of the ion guide settings, as reported here, eliminate the phenomenon without sacrificing signal intensity. Such gas-phase deuterium loss should be appreciated for all HDX-MS studies using such ion optics, even for routine studies not focused on interpreting bimodal spectra. Graphical Abstract ᅟ.

  11. Non-centrosymmetric behavior of a clay film ion-exchanged with chiral metal complexes.

    Science.gov (United States)

    Suzuki, Yasutaka; Matsunaga, Ryoya; Sato, Hisako; Kogure, Toshihiro; Yamagishi, Akihiko; Kawamata, Jun

    2009-12-07

    SHG measurements on a highly transparent clay film ion-exchanged with chiral metal complexes revealed that the mono-molecular layer of the chiral complexes in an interlayer space acquired a non-centrosymmetric character.

  12. Adsorption Mechanisms of Heavy Metal Ions from Drinking Water by Weakly Basic Anion Exchange Resins

    Institute of Scientific and Technical Information of China (English)

    赵璇; 何仕均; 杨磊

    2002-01-01

    Heavy metal micro-contaminants can be removed from water sources technologies. Weakly basic anion exchange resins offer the best ability to remove trace amounts of heavy metals with high selectivity. This paper discusses how weakly basic resins adsorb heavy metals using two different approaches. The removal of mercury, cadmium, and lead ions is based on the fundamental theory of coordination chemistry. The mechanism is not ion exchange but extractive adsorption of heavy metal salts. However, the marked preferential adsorption of chromate by weakly basic anion exchange can be explained using the traditional theory of ion exchange. A lab-scale study produced positive results for the removal of trace amounts of heavy metal ions from drinking water.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

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

    1981-01-01

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

  15. Media selection in ion-exchange chromatography in a single microplate.

    Science.gov (United States)

    Cabanne, Charlotte; Santarelli, Xavier

    2014-01-01

    High-throughput process development is more and more used in chromatography. Limitations are the tools provided by the manufacturers. Here, we describe a method to select chromatographic media for ion-exchange chromatography using a 96-well filter microplate.

  16. Separation of Radioactive Elements Using Nitrogen Oxygen Donor Macrocyclic Ion Exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Si Joong; Shim, Min Sook [Korea University, Seoul (Korea, Republic of); Kim, Jeong; Lee, Myung No [Seonam University, Namwon (Korea, Republic of)

    1997-07-01

    The study for the selective separation and recovery of Pd{sup 2+} ion lead to following results. The four kinds of stationary phase, SGB-NTOE, SGB-NTOT, SGB-NEOD, and SGB-NTOD, were synthesized to react NOTE, NTOT, NEOD, and NTOD with 3-glycidyloxypropyltrimethoxy silane and silica gel. Using these macrocycles, selective separation of Hg(II), Pt(II), and Pd(II) from alkali earth and transition metal ions were possible by column chromatography. Maximum separation capability was appeared in SGB-NTOT and it took 12 hours for complete separation of Pd{sup 2+} ion with the column which inner diameter was 24 cm. The results of the study for the selective separation of Cs{sup +} and Sr{sup 2+} are as follows: Sr{sup 2+} ion was effectively separated through liquid membrane with CR22BB and the relative transport ration of Sr{sup 2+}/Na{sup +} was 15. Cs{sup +} ion was effectively separated through liquid membrane with CR22BB(OH)Ph and the relative transport ration of Cs{sup +}/Na{sup +} was 3.4. 9 refs., 7 tabs., 15 figs. (author)

  17. Ion Exchange and Solvent Extraction: Supramolecular Aspects of Solvent Exchange Volume 21

    Energy Technology Data Exchange (ETDEWEB)

    Gloe, Karsten [Technischen Universität Dresden; Tasker, Peter A [ORNL; Oshima, Tatsuya [University of Miyazaki; Watarai, Hitoshi [Institute for NanoScience Design at Osaka University; Nilsson, Mikael [University of California, Irvine

    2013-01-01

    Preface The theme of supramolecular chemistry (SC), entailing the organization of multiple species through noncovalent interactions, has permeated virtually all aspects of chemical endeavor over the past several decades. Given that the observed behavior of discrete molecular species depends upon their weak interactions with one another and with matrix components, one would have to conclude that SC must indeed form part of the fabric of chemistry itself. A vast literature now serves to categorize SC phenomena within a body of consistent terminology. The word supramolecular itself appears in the titles of dozens of books, several journals, and a dedicated encyclopedia. Not surprisingly, the theme of SC also permeates the field of solvent extraction (SX), inspiring the framework for this volume of Ion Exchange and Solvent Extraction. It is attempted in the six chapters of this volume to identify both how supramolecular behavior occurs and is studied in the context of SX and how SC is influencing the current direction of SX. Researchers and practitioners have long dealt with supramolecular interactions in SX. Indeed, the use of polar extractant molecules in nonpolar media virtually assures that aggregative interactions will dominate the solution behavior of SX. Analytical chemists working in the 1930s to the 1950s with simple mono- and bidentate chelating ligands as extractants noted that extraction of metal ions obeyed complicated mass-action equilibria involving complex stoichiometries. As chemists and engineers developed processes for nuclear and hydrometallurgical applications in the 1950s and 1960s, the preference for aliphatic diluents only enhanced the complexity and supramolecular nature of extraction chemistry. Use of physical techniques such as light scattering and vapor-pressure measurements together with various spectroscopic methods revealed organic-phase aggregates from well-defined dimers to small aggregates containing a few extractant molecules to large

  18. CIM(®) monolithic anion-exchange chromatography as a useful alternative to CsCl gradient purification of bacteriophage particles.

    Science.gov (United States)

    Adriaenssens, Evelien M; Lehman, Susan M; Vandersteegen, Katrien; Vandenheuvel, Dieter; Philippe, Didier L; Cornelissen, Anneleen; Clokie, Martha R J; García, Andrés J; De Proft, Maurice; Maes, Martine; Lavigne, Rob

    2012-12-20

    The use of anion-exchange chromatography was investigated as an alternative method to concentrate and purify bacterial viruses, and parameters for different bacteriophages were compared. Chromatography was performed with Convective Interactive Media(®) monoliths, with three different volumes and two matrix chemistries. Eleven morphologically distinct phages were tested, infecting five different bacterial species. For each of the phages tested, a protocol was optimized, including the choice of column chemistry, loading, buffer and elution conditions. The capacity and recovery of the phages on the columns varied considerably between phages. We conclude that anion-exchange chromatography with monoliths is a valid alternative to the more traditional CsCl purification, has upscaling advantages, but it requires more extensive optimization.

  19. Hydrogen adsorption over Zeolite-like MOF materials modified by ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Calleja, G.; Botas, J.A.; Orcajo, M.G. [Department of Chemical and Energy Technology, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, 28933 Mostoles, Madrid (Spain); Sanchez-Sanchez, M. [Instituto de Catalisis y Petroleoquimica, CSIC, C/Marie Curie 2, 28049 Madrid (Spain)

    2010-09-15

    Novel porous Zeolite-like metal-organic framework (ZMOF) materials with Rho and Sod topologies are promising adsorbents for hydrogen storage due to their high surface area and, more importantly, to their capacity of being ion-exchanged, potentially changing their affinity for hydrogen. In this work, we have successfully synthesized both Rho and SodZMOF materials, optimizing experimental conditions for scaling-up the procedure already published to produce grams of material. The resultant materials were alkaline-cation-exchanged, widely characterized and finally tested as hydrogen adsorbents. RhoZMOF is converted into an amorphous phase during some of the ion-exchange processes, whereas SodZMOF, whose ion-exchange capacity has not been investigated so far, always maintains its topology for any tested exchange cation and conditions. Additionally, thermogravimetric analyses and thermal treatments followed by in-situ powder X-ray diffraction analysis have evidenced a significantly higher thermal stability of both as-prepared and ion-exchanged SodZMOF materials in comparison to their Rho-structured homologues. Moreover, the thermal stability of the cation-exchanged ZMOF samples improves when methanol is the ion-exchange solvent rather than the reported ethanol-water mixture. Nitrogen and hydrogen adsorption isotherms at 77 K suggested that alkali-exchanged materials have lower affinity for hydrogen than the as-prepared samples compensated by imidazolium ion; however, due to the smaller size of Na{sup +} or Li{sup +} cations, their lower affinity is easily compensated by the inherent increase in surface area and pore volume as exchange degree increases. (author)

  20. Analyzing the effect of ion exchange on flexural strength of cermaco II and colorlogic veneer porcelains

    OpenAIRE

    N. Rashidan; HA. Mahgoli

    1998-01-01

      The major foible of dental ceramics is their brittle nature. Therefore, the producers of these materials have focused on the “strength” issue. A method of increasing strength is ion exchange on porcelain surface which leads to formation of a compressive crust that opposing forces should overcome before developing a crack. In current study, ion exchange in two types of porcelain, Ceramco II which is used in PFM restorations and Colorloic veneer which is used for laminates, veneers, inlays an...

  1. Experimental Ion Exchange Column With SuperLig 639 And Simulant Formulation

    Energy Technology Data Exchange (ETDEWEB)

    Morse, Megan; Nash, C.

    2013-08-26

    SuperLig®639 ion exchange resin was tested as a retrieval mechanism for pertechnetate, through decontamination of a perrhenate spiked 5M Simple Average Na{sup +} Mass Based Simulant. Testing included batch contacts and a three-column ion exchange campaign. A decontamination of perrhenate exceeding 99% from the liquid feed was demonstrated. Analysis of the first formulation of a SBS/WESP simulant found unexpectedly low concentrations of soluble aluminum. Follow-on work will complete the formulation.

  2. Lawps ion exchange column gravity drain of spherical resorcinol formaldehyde resin

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Herman, D. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Restivo, M. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-01-28

    Experiments at several different scales were performed to understand the removal of spherical resorcinol formaldehyde (sRF) ion exchange resin using a gravity drain system with a valve located above the resin screen in the ion exchange column (IXC). This is being considered as part of the design for the Low Activity Waste Pretreatment System (LAWPS) to be constructed at the DOE Hanford Site.

  3. "One-Pot" Ion-Exchange and Mesopore Formation During Desilication

    DEFF Research Database (Denmark)

    Holm, Martin Spangsberg; Hansen, Martin Kalmar; Christensen, Claus Hviid

    2009-01-01

    A desilication protocol using tetramethylammonium hydroxide was applied to zeolite beta. The new route presented here integrates the desilication and ion-exchange post-treatment steps allowing for a subsequent ion-exchange step to be avoided. It is shown that the acidic and highly mesoporous zeol...... zeolite is obtained directly upon calcination. Thus, careful choice of base and post-treatment conditions lead to the fabrication of a hierarchical meso- and microporous structure with completely retained crystallinity. (...

  4. A Simple and Efficient Method for Purification of Egg White Major Proteins Using Ion Exchange Chromatography

    OpenAIRE

    Sh. Veisi; A. Mostafaie; Z. Mohammad Hasan

    2008-01-01

    Introduction & Objective: Egg white contains four high-quantity proteins which have numerous applications. In this research, a simple and efficient method for the purification of those proteins was designed and performed based on ion exchange chromatography.Materials & Methods: In this experimental study egg white was initially separated from insoluble substances by acidic pH. The resulting extract was isolated after two steps of ion exchange chromatography using CM-Sepharose and DEAE-Sepharo...

  5. Immobilization of ion exchange radioactive resins of the TRIGA Mark III nuclear reactor; Inmovilizacion de resinas de intercambio ionico radiactivas del reactor nuclear Triga Mark III

    Energy Technology Data Exchange (ETDEWEB)

    Garcia M, H.; Emeterio H, M.; Canizal S, C. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, C.P. 11801 Mexico D.F. (Mexico)

    2000-07-01

    This work has the objective to develop the process and to define the agglutinating material which allows the immobilization of the ion exchange radioactive resins coming from the TRIGA Mark III nuclear reactor contaminated with Ba-133, Co-60, Cs-137, Eu-152, and Mn-54 through the behavior analysis of different immobilization agents such as: bitumens, cement and polyester resin. According to the International Standardization the archetype samples were observed with the following tests: determination of free liquid, leaching, charge resistance, biodegradation, irradiation, thermal cycle, burned resistance. Generally all the tests were satisfactorily achieved, for each agent. Therefore, the polyester resin could be considered as the main immobilizing. (Author)

  6. Performance evaluation of 24 ion exchange materials for removing cesium and strontium from actual and simulated N-Reactor storage basin water

    Energy Technology Data Exchange (ETDEWEB)

    Brown, G.N.; Carson, K.J.; DesChane, J.R.; Elovich, R.J.

    1997-09-01

    This report describes the evaluation of 24 organic and inorganic ion exchange materials for removing cesium and strontium from actual and simulated waters from the 100 Area 105 N-Reactor fuel storage basin. The data described in this report can be applied for developing and evaluating ion exchange pre-treatment process flowsheets. Cesium and strontium batch distribution ratios (K{sub d}`s), decontamination factors (DF), and material loadings (mmol g{sup -1}) are compared as a function of ion exchange material and initial cesium concentration. The actual and simulated N-Basin waters contain relatively low levels of aluminum, barium, calcium, potassium, and magnesium (ranging from 8.33E-04 to 6.40E-05 M), with slightly higher levels of boron (6.63E-03 M) and sodium (1.62E-03 M). The {sup 137}Cs level is 1.74E-06 Ci L-{sup 1} which corresponds to approximately 4.87E-10 M Cs. The initial Na/Cs ratio was 3.33E+06. The concentration of total strontium is 4.45E-06 M, while the {sup 90}Sr radioactive component was measured to be 6.13E-06 Ci L{sup -1}. Simulant tests were conducted by contacting 0.067 g or each ion exchange material with approximately 100 mL of either the actual or simulated N-Basin water. The simulants contained variable initial cesium concentrations ranging from 1.00E-04 to 2.57E- 10 M Cs while all other components were held constant. For all materials, the average cesium K{sub d} was independent of cesium concentration below approximately 1.0E-06 M. Above this level, the average cesium K{sub d} values decreased significantly. Cesium K{sub d} values exceeding 1.0E+07 mL g{sup -1} were measured in the simulated N-Basin water. However, when measured in the actual N-Basin water the values were several orders of magnitude lower, with a maximum of 1.24E+05 mL g{sup -1} observed.

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

    Science.gov (United States)

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

    2004-07-12

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

  8. Influence of Ionic Liquids on the Selectivity of Ion Exchange-Based Polymer Membrane Sensing Layers.

    Science.gov (United States)

    Mendecki, Lukasz; Callan, Nicole; Ahern, Meghan; Schazmann, Benjamin; Radu, Aleksandar

    2016-07-16

    The applicability of ion exchange membranes is mainly defined by their permselectivity towards specific ions. For instance, the needed selectivity can be sought by modifying some of the components required for the preparation of such membranes. In this study, a new class of materials -trihexyl(tetradecyl)phosphonium based ionic liquids (ILs) were used to modify the properties of ion exchange membranes. We determined selectivity coefficients for iodide as model ion utilizing six phosphonium-based ILs and compared the selectivity with two classical plasticizers. The dielectric properties of membranes plasticized with ionic liquids and their response characteristics towards ten different anions were investigated using potentiometric and impedance measurements. In this large set of data, deviations of obtained selectivity coefficients from the well-established Hofmeister series were observed on many occasions thus indicating a multitude of applications for these ion-exchanging systems.

  9. Effect of grinding and fluoride-gel exposure on strength of ion-exchanged porcelain.

    Science.gov (United States)

    Anusavice, K J; Hojjatie, B; Chang, T C

    1994-08-01

    Strengthening of dental porcelain through a diffusion heat treatment at 450 degrees C of a potassium-enriched, ion-exchange surface coating has been demonstrated in several recent studies. However, little attention has been focused on the potential strength reduction of these materials when the treated surfaces are ground or etched under clinically simulated conditions. The objective of this study was to test the hypothesis that partial removal of the surface layers of ion-exchanged porcelains by grinding or exposure to acidulated fluoride gel will significantly reduce their flexure strength. Nine groups of body porcelain disks were ion-exchanged at 450 degrees C for 30 min. One of these groups was subjected to ion exchange and no further surface treatment. Eight specimen groups were subjected to the following procedures after ion exchange: grinding to depths of 50 microns, 100 microns, 150 microns, 200 microns, and 250 microns, and exposure to acidulated fluoride for 30 min, 60 min, and 300 min. A tenth group (FC) was fired at 960 degrees C and fast-cooled in air, but the disks were not subjected to the ion-exchange treatment. Surface stress was calculated from measured values of cracks induced in the treated surfaces. Fluoride exposure for up to 60 min resulted in a significant decrease in surface compression (P 0.05).

  10. Reducing ion exchange resins rad-wastes, experience at EDF PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Fene, G. [Rohm and Haas Co. (France); Hoffman, B. [Rohm and Haas Co. (United States)

    2002-07-01

    Life time of an ion exchange resin in a Nuclear Power Station (EDF PWR). At the end of its life, an ion exchange resin which has been used to treat radioactive streams becomes a radwaste itself. Its level of radioactivity depends on the point of use and consequently on the circuit where it was used. Roughly speaking, in a Nuclear Power Station PWR we can consider two types of radwaste families: High radioactive family Ion exchange resins which come from primary circuit: reactor control and storage pools. Ion exchange resins which have worked in a decontamination circuit: waste water treatment. Low radioactive family Ion exchange resins which come from secondary circuit: Steam Generator Blowdown By understanding and carefully applying some critical properties of ion exchange resins, such as total capacity, selectivity, and physical structure, it is possible for nuclear power stations to minimize radwaste volumes, while at the same time improving plant performance. This type of improvement can be facilitated by close cooperation and communication between the resin producer and the nuclear power user. (authors)

  11. ROTARY FILTER FINES TESTING FOR SMALL COLUMN ION EXCHANGE

    Energy Technology Data Exchange (ETDEWEB)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  13. Synthesis, Characterization and Ion Exchange Properties of a New Composite of Inorganic Ion Exchanger: Polyacrylonitrile Cerium(IV) Molybdophosphate%Synthesis, Characterization and Ion Exchange Properties of a New Composite of Inorganic Ion Exchanger: Polyacrylonitrile Cerium(IV) Molybdophosphate

    Institute of Scientific and Technical Information of China (English)

    Ahmadi, Seyed Javad; Yavari, Ramin; Ashtari, Parviz'; Gholipour, Vanik; Kamel, Leila; Rakhshandehru, Farokh

    2012-01-01

    In this work, the synthesis of the composite of cerium(IV) molybdophosphate (CMP) and polyacrylonitrile (PAN) was reported (CMP-PAN). The material has been characterized by elemental and spectral (FT-IR), X-ray and thermal (TGA) analysis. Also the size analysis of the composite was done by scanning electron microscopy (SEM). Its chemical stability in acidic, basic and saline solutions and radiation stability up to 100 kGy total expose dose were assessed. Whereas the synthesized composite has ion exchange properties, its ion exchange capacity and behavior toward several metal ions were also investigated. Further, the distribution coefficients of the metal ions were calculated. Finally, the ability of the synthesized CMP-PAN composite for the decontamination of low level liquid waste (LLLW) was investigated.

  14. PILOT-SCALE HYDRAULIC TESTING OF RESORCINOL FORMALDEHYDE ION EXCHANGE RESIN

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, D.

    2009-05-28

    Savannah River National Laboratory (SRNL) performed pilot-scale hydraulic/chemical testing of spherical resorcinol formaldehyde (RF) ion exchange (IX) resin for the River Protection Project-Hanford Tank Waste Treatment & Immobilization Plant (WTP) Project. The RF resin hydraulic cycle testing was conducted in two pilot-scale IX columns, 1/4 and 1/2 scale. A total of twenty-three hydraulic/chemical cycles were successfully completed on the spherical RF resin. Sixteen of these cycles were completed in the 24-inch IX Column (1/2 scale column). Hydraulic testing showed that the permeability of the RF resin remained essentially constant, with no observed trend in the reduction of the permeability as the number of cycles increased. The permeability during the pilot-scale testing was 3 times better than the design requirements of the WTP full-scale IX system. The RF resin bed showed no tendency to form fissures or pack more densely as the number of cycles increased. Particle size measurements of the RF resin showed no indication of particle size change (for a given chemical) with cycles and essentially no fines formation. The permeability of the resin bed was uniform with respect to changes in bed depth. Upflow Regeneration and Simulant Introduction in the IX columns revealed another RF resin benefit; negligible radial pressures to the column walls from the swelling of resin beads. The hydraulic and chemical performance of the spherical RF resin during cycle testing was found to be superior to all other tested IX resins. The pilot-scale testing indicates that the RF resin is durable and should hold up to many hydraulic cycles in actual radioactive Cesium (Cs) separation.

  15. Competitive migration behaviors of multiple ions and their impacts on ion-exchange resin packed microbial desalination cell.

    Science.gov (United States)

    Zuo, Kuichang; Yuan, Lulu; Wei, Jincheng; Liang, Peng; Huang, Xia

    2013-10-01

    Mixed ion-exchange resins packed microbial desalination cell (R-MDC) could stabilize the internal resistance, however, the impacts of multiple ions on R-MDC performance was unclear. This study investigated the desalination performance, multiple ions migration behaviors and their impacts on R-MDCs fed with salt solution containing multiple anions and cations. Results showed that R-MDC removed multiple anions better than multiple cations with desalination efficiency of 99% (effluent conductivity NO3(-)>Cl(-) for anions and Ca(2+)≈Mg(2+)>NH4(+)>Na(+) for cations, jointly affected by both their molar conductivity and exchange selectivity on resins. After long-term operation, the existence of higher concentration Ca(2+) and Mg(2+) caused the electric conductivity of mixed resins decrease and scaling on the surface of cation-exchange membrane adjoined with cathode chamber, suggesting that R-MDC would be more suitable for desalination of water with lower hardness.

  16. Intensification of ammonia removal from waste water in biologically active zeolitic ion exchange columns.

    Science.gov (United States)

    Almutairi, Azel; Weatherley, Laurence R

    2015-09-01

    The use of nitrification filters for the removal of ammonium ion from waste-water is an established technology deployed extensively in municipal water treatment, in industrial water treatment and in applications such as fish farming. The process involves the development of immobilized bacterial films on a solid packing support, which is designed to provide a suitable host for the film, and allow supply of oxygen to promote aerobic action. Removal of ammonia and nitrite is increasingly necessary to meet drinking water and discharge standards being applied in the US, Europe and other places. Ion-exchange techniques are also effective for removal of ammonia (as the ammonium ion) from waste water and have the advantage of fast start-up times compared to biological filtration which in some cases may take several weeks to be fully operational. Here we explore the performance of ion exchange columns in which nitrifying bacteria are cultivated, with the goal of a "combined" process involving simultaneous ion-exchange and nitrification, intensified by in-situ aeration with a novel membrane module. There were three experimental goals. Firstly, ion exchange zeolites were characterized and prepared for comparative column breakthrough studies for ammonia removal. Secondly effective in-situ aeration for promotion of nitrifying bacterial growth was studied using a number of different membranes including polyethersulfone (PES), polypropylene (PP), nylon, and polytetra-fluoroethylene (PTFE). Thirdly the breakthrough performance of ion exchange columns filled with zeolite in the presence of aeration and in the presence of nitrifying bacteria was determined to establish the influence of biomass, and aeration upon breakthrough during ammonium ion uptake. The methodology adopted included screening of two types of the naturally occuring zeolite clinoptilolite for effective ammonia removal in continuous ion-exchange columns. Next, the performance of fixed beds of clinoptilolite in the

  17. Development of a transparent, non-cytotoxic, silver ion-exchanged glass with antimicrobial activity and low ion elution.

    Science.gov (United States)

    Shim, Gyu-In; Kim, Seong-Hwan; Eom, Hyung-Woo; Kim, Kwang-Mahn; Choi, Se-Young

    2015-05-01

    We investigated the antimicrobial, cytotoxicity, skin irritation, and ion elution behaviors of glass doped with silver ions with respect to its application to electronic equipment such as phones and tablet screens. The microbes tested were Escherichia coli, Staphylococcus aureus, and Penicillium funiculosum. AgNO3 powder was spread on both sides of aluminosilicate glass, and it was heated to 250-280°C for 10min. Under optimized heating conditions (260°C, 10min), the antimicrobial activity of ion-exchanged glass against bacteria and fungi was over 99.9% after 24 weeks. The glass failed to irritate the skin of experimental animals and was considered non-cytotoxic. The maximum amount of Ag ions that were eluted from the ion-exchanged glass into drinking water was measured at 0.037±0.003μgL(-1), an amount which is several orders of magnitude below the standard limit of 0.1mgL(-1) in drinking water. Ag ion-exchanged glass had characteristics suitable for use as a display screen, such as a light transmittance of 90% and a surface roughness of 0.704nm. Our findings suggest that glass doped with silver ions is more hygienic than non-doped glass is, and should be applied to display screens and glassware.

  18. Synthesis and characterization of functional peek for ion-exchange membranes

    CSIR Research Space (South Africa)

    Luo, H

    2010-03-01

    Full Text Available The sulfonated and sulfinated polyetheretherketone (SsPEEK) was prepared via a novel method. SsPEEK has two types of functional groups, the functional groups for ion-exchange and the functional groups for further strengthening of the ion...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Absorbance of UO{sub 2}{sup 2+} ion in NaCl-2CsCl molten salt

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Fuminori; Tayama, Toshimitsu [Japan Nuclear Cycle Development Inst., Tokai Works, Tokai, Ibaraki (Japan); Nagai, Takayuki [Japan Nuclear Cycle Development Inst., Innovative Research Promotion Office, Tokai, Ibaraki (Japan)

    2003-06-01

    In Feasibility Studies (FS) for the commercialized fast breeder reactor (FBR) cycle system, the oxide electrowinning process is being developed by Japan Nuclear Cycle Development Institute (JNC). In the oxide electrowinning process, spent nuclear fuel is dissolved into molten salt and U and Pu are recovered as MOX by MOX-electrolysis. MOX-electrolysis has many requirements such as U/Pu ratio controls and separation from FP of U-Pu. Therefore, it is necessary to analyze the amounts of nuclear material (U and Pu) in the molten salt and control MOX-electrolysis based on this analysis result. This report considers the optical method as one candidate for process analysis technology. Absorbance of UO{sub 2}{sup 2+} ion, the basic data for optical analysis, was measured in NaCl-2CsCl molten salt. Although Khokhryakov reported on UO{sub 2}{sup 2+} absorbance using the Reflection-Absorption method no detailed report exists on the relation between absorbance and UO{sub 2}{sup 2+} concentration. Therefore, necessary spectral data for the process analysis technology were collected by the experiment. (author)

  1. Composite Membranes Containing Nanoparticles of Inorganic Ion Exchangers for Electrodialytic Desalination of Glycerol

    Science.gov (United States)

    Dzyazko, Yu S.; Rozhdestvenska, L. M.; Vasilyuk, S. L.; Kudelko, K. O.; Belyakov, V. N.

    2017-06-01

    Composite membranes were obtained by modification of heterogeneous polymer cation and anion-exchange membranes with nanoparticles of zirconium hydrophosphate and hydrated zirconium dioxide, respectively. The ion-exchange materials were investigated with the methods of electron microscopy, potentiometry, voltammetry, and impedance spectroscopy. Single nanoparticles, which were precipitated in aqueous media, form aggregates, when the composites are in a contact with polar organic solvent. Both single nanoparticles (up to 10 nm) and their aggregates (up to 200 nm) were precipitated in ion-exchange polymers in glycerol media. Non-aggregated nanoparticles improve electrical conductivity of the ion-exchange materials, the aggregates are barriers against fouling. The membranes were applied to NaCl removal from highly concentrated glycerine-water mixture containing organic additives (byproduct of biodiesel production). As opposite to pristine materials, the composites demonstrate stability against fouling.

  2. Preparation and emanation properties of an ion-exchanged solid thoron source.

    Science.gov (United States)

    Tang, F; Zhuo, W; He, L; Zhao, C; Xu, Y

    2012-11-01

    For the calibration purpose of thoron ((220)Rn) measurements, solid sources with constant (220)Rn emanation are generally desired. In this study, Th(4+) in the thorium nitrate powder was successfully exchanged to the surfaces of sodium benzenesulphonate resins with a bead diameter of ∼0.5 mm by using the ion-exchange method. Tests of (220)Rn emanating from the ion-exchanged resin indicated that the emanation rates were nearly constant, provided both the air humidity and air temperature were controlled. As the resin can be easily prepared to be of various sizes and activities of sources, the ion-exchanged resin is considered as a promising standard source for calibrations of (220)Rn measurements.

  3. Preparation of bioconjugates by solid-phase conjugation to ion exchange matrix-adsorbed carrier proteins

    DEFF Research Database (Denmark)

    Houen, G.; Olsen, D.T.; Hansen, P.R.;

    2003-01-01

    A solid-phase conjugation method utilizing carrier protein bound to an ion exchange matrix was developed. Ovalbumin was adsorbed to an anion exchange matrix using a batch procedure, and the immobilized protein was then derivatized with iodoacetic acid N-hydroxysuccinimid ester. The activated......, and immunization experiments with the eluted conjugates showed that the more substituted conjugates gave rise to the highest titers of glutathione antibodies. Direct immunization with the conjugates adsorbed to the ion exchange matrix was possible and gave rise to high titers of glutathione antibodies. Conjugates...... of ovalbumin and various peptides were prepared in a similar manner and used for production of peptide antisera by direct immunization with the conjugates bound to the ion exchanger. Advantages of the method are its solid-phase nature, allowing fast and efficient reactions and intermediate washings...

  4. Separation of hemicellulose-derived saccharides from wood hydrolysate by lime and ion exchange resin.

    Science.gov (United States)

    Wang, Xiaojun; Zhuang, Jingshun; Fu, Yingjuan; Tian, Guoyu; Wang, Zhaojiang; Qin, Menghua

    2016-04-01

    A combined process of lime treatment and mixed bed ion exchange was proposed to separate hemicellulose-derived saccharides (HDS) from prehydrolysis liquor (PHL) of lignocellulose as value added products. The optimization of lime treatment achieved up to 44.2% removal of non-saccharide organic compounds (NSOC), mainly colloidal substances, with negligible HDS degradation at 0.5% lime level and subsequent neutralization by phosphoric acid. The residual NSOC and calcium ions in lime-treated PHL were eliminated by mixed bed ion exchange. The breakthrough curves of HDS and NSOC showed selective retention toward NSOC, leading to 75% HDS recovery with 95% purity at 17 bed volumes of exchange capacity. In addition, macroporous resin showed higher exchange capacity than gel resin as indicated by the triple processing volume. The remarkable selectivity of the combined process suggested the feasibility for HDS separation from PHL.

  5. Electrochemically Controlled Ion-exchange Property of Carbon Nanotubes/Polypyrrole Nanocomposite in Various Electrolyte Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Daiwon [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; Zhu, Chengzhou [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Fu, Shaofang [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Du, Dan [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States; Engelhard, Mark H. [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; Lin, Yuehe [Pacific Northwest National Laboratory, 902 Battelle Boulevard P.O. Box 999 Richland WA 99352 USA; School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99164-2920 United States

    2016-09-15

    The electrochemically controlled ion-exchange properties of multi-wall carbon nanotube (MWNT)/electronically conductive polypyrrole (PPy) polymer composite in the various electrolyte solutions have been investigated. The ion-exchange behavior, rate and capacity of the electrochemically deposited polypyrrole with and without carbon nanotube (CNT) were compared and characterized using cyclic voltammetry (CV), chronoamperometry (CA), electrochemical quartz crystal microbalance (EQCM), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). It has been found that the presence of carbon nanotube backbone resulted in improvement in ion-exchange rate, stability of polypyrrole, and higher anion loading capacity per PPy due to higher surface area, electronic conductivity, porous structure of thin film, and thinner film thickness providing shorter diffusion path. Chronoamperometric studies show that electrically switched anion exchange could be completed more than 10 times faster than pure PPy thin film. The anion selectivity of CNT/PPy film is demonstrated using X-ray photoelectron spectroscopy (XPS).

  6. Fractioning electrodialysis: a current induced ion exchange process

    NARCIS (Netherlands)

    Galama, A.H.; Daubaras, G.; Burheim, O.S.; Rijnaarts, H.; Post, J.W.

    2014-01-01

    In desalination often multi ionic compositions are encountered. A preferential removal of multivalent ions over monovalent ions can be of interest to prevent scaling in the desalination process. Recently, a novel fractionating electrodialysis stack is described by Zhang et al., 2012 (in Sep. purify.

  7. Fractioning electrodialysis : a current induced ion exchange process

    NARCIS (Netherlands)

    Galama, A. H.; Daubaras, G.; Burheim, O. S.; Rijnaarts, H. H. M.; Post, J. W.

    2014-01-01

    In desalination often multi ionic compositions are encountered. A preferential removal of multivalent ions over monovalent ions can be of interest to prevent scaling in the desalination process. Recently, a novel fractionating electrodialysis stack is described by Zhang et al., 2012 (in Sep. purify.

  8. Continuous Separation of Cesium Based on NiHCF/PTCF Electrode by Electrochemically Switched Ion Exchange

    Institute of Scientific and Technical Information of China (English)

    孙斌; 郝晓刚; 王忠德; 张忠林; 刘世斌; 官国清

    2012-01-01

    Nickel hexacyanoferrate (NiHCF) film was synthesized on porous three-dimensional carbon felt (PTCF) substrate by repetitious batch chemical depositions, and the NiHCF/PTCF electrode was used as electrochemically switched ion exchange (ESIX) electrode in a packed bed for continuous separation for cesium ions. The morphologies of the prepared electrodes were characterized by scanning electron microscopy and the effects of solution concentration on the ion-exchange capacity of the electrodes were investigated by cyclic voltammetry technique. Cycling stability and long-term storage stability of NiHCF/PTCF electrodes were also studied. The NiHCF/PTCF electrodes with excellent ion-exchange ability were used to assemble a diaphragm-isolated ESIX reactor for cesium separation. Continuous separation of cesium and regeneration of NiHCF/PTCF electrode based on the diaphragm-isolated reactor were performed in a laboratory-scale two-electrode system.

  9. The influence of silver ion exchange on the luminescence properties of Er-Yb silicate glasses

    Science.gov (United States)

    Stanek, S.; Nekvindova, P.; Svecova, B.; Vytykacova, S.; Mika, M.; Oswald, J.; Barkman, O.; Spirkova, J.

    2017-10-01

    A set of zinc-silicate glasses with different ratios of Er-Yb as well amount of Zn was fabricated. The preparation of silver doped glasses was carried out using the Ag-Na ion-exchange method to enhance Er-Yb luminescence properties of the material. The samples were also annealed for 1-5 h to further support the creation of silver nanoparticles. Intensive absorption at 980 nm was observed in absorption spectra after ion exchange and annealing as well. Also luminescence spectra in the near-infrared range were measured and results showed positive effect of ion exchange process on luminescence properties. Luminescence intensity at 1530 nm was increased almost three times. Possible mechanisms responsible for the increase of the luminescence intensity are also discussed in this paper. We suggest that the enhancement of erbium luminescence intensity is caused by the energy transfer from isolated Ag+ ions to Er.

  10. Central metal ion exchange in a coordination polymer based on lanthanide ions and di(2-ethylhexyl)phosphoric acid: exchange rate and tunable affinity.

    Science.gov (United States)

    Tasaki-Handa, Yuiko; Abe, Yukie; Ooi, Kenta; Tanaka, Mikiya; Wakisaka, Akihiro

    2014-01-01

    In this paper the exchange of lanthanide(III) ions (Ln(3+)) between a solution and a coordination polymer (CP) of di(2-ethylhexyl)phosphoric acid (Hdehp), [Ln(dehp)3], is studied. Kinetic and selectivity studies suggest that a polymeric network of [Ln(dehp)3] has different characteristics than the corresponding monomeric complex. The reaction rate is remarkably slow and requires over 600 h to reach in nearly equilibrium, and this can be explained by the polymeric crystalline structure and high valency of Ln(3+). The affinity of the exchange reaction reaches a maximum with the Ln(3+) possessing an ionic radius 7% smaller than that of the central Ln(3+), therefore, the affinity of the [Ln(dehp)3] is tunable based on the choice of the central metal ion. Such unique affinity, which differs from the monomeric complex, can be explained by two factors: the coordination preference and steric strain caused by the polymeric structure. The latter likely becomes predominant for Ln(3+) exchange when the ionic radius of the ion in solution is smaller than the original Ln(3+) by more than 7%. Structural studies suggest that the incoming Ln(3+) forms a new phase though an exchange reaction, and this could plausibly cause the structural strain.

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

    Science.gov (United States)

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

    2013-11-01

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

  12. Thermodynamics of ion exchange equilibrium for some uni-univalent and divalent reaction systems using strongly basic anion exchange resin Indion FF-IP

    Directory of Open Access Journals (Sweden)

    P.U. Singare

    2008-12-01

    Full Text Available The study on thermodynamics of ion exchange equilibrium for uni-univalent Cl-/I-, Cl-/Br-, and uni-divalent Cl-/SO42-, Cl-/C2O42- reaction systems was carried out using ion exchange resin Indion FF-IP. The equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well as in the resin phase. For uni-univalent ion exchange reaction systems, the equilibrium constant K’ were also calculated by considering mole fraction of ions in the resin phase. The K values calculated for uni-univalent and uni-divalent anion exchange reaction systems were observed to increase with rise in temperature, indicating the endothermic exchange reactions having enthalpy values of 22.45, 28.57, 17.84, 15.97 kJ/mol, respectively.

  13. Ion exchange properties of Wyodak premium coal samples

    Energy Technology Data Exchange (ETDEWEB)

    Vorres, K.S.

    1993-08-23

    Low rank coals (lignite and subbituminous) contain exchangeable cations. A sample of {minus}20+200 mesh Argonne Premium Wyodak coal was washed with nitric acid in a burette fitted with a coarse glass frit at the base of the graduations to remove the exchangeable cations from the system. The eluent was passed to a flow-through pH electrode and a titration curve was obtained on a computer file. A series of electrodes (pH, calcium, sodium and potassium) were used in separate experiments to follow the elution from the coal. Some implications for coal structure are also indicated.

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

    DEFF Research Database (Denmark)

    Christensen, Søren Gregers; Thomsen, Kaj

    2005-01-01

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

  15. Modelling of graded index waveguide fabricated by ion exchange on Er3+ doped glass

    Institute of Scientific and Technical Information of China (English)

    Shao Gong-Wang; Jin Guo-Liang

    2009-01-01

    A general numerical tool, based on thermal diffusion equation and full-vectorial eigen-mode equation, has been presented for the systematic analysis of graded index channel waveguide fabricated by ion exchange on Er3+ doped glass. Finite difference method with full-vectorial formulation (FV-FDM) is applied to solving the full-vectorial modes of graded index channel waveguide for the first time. The coupled difference equations based on magnetic fields in FV-FDM are derived from the Taylor series expansion and accurate formulation of boundary conditions. Hybrid nature of vectorial guided modes for both pump (980 nm) and signal light (1550 nm) are demonstrated by the simulation. Results show that the fabrication parameters of ion exchange, such as channel opening width and time ratio of second step to first step in ion exchange, have large influence on the properties of waveguide. By optimizing the fabrication parameters, maintenance of monomode for signal light and improvement of the gain dynamics can be achieved in Er3+ doped waveguide amplifier (EDWA) fabricated by ion exchange technique. This theoretical model is significant for the design and fabrication of EDWA with ion exchange technique. Furthermore, a single polarization EDWA, which operates at wavelength from 1528 nm to 1541 nm for HE polarization, is numerically designed.

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

    Science.gov (United States)

    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.

  17. STUDIES ON INOSINE EXTRACTION BY ION EXCHANGE METHOD

    Institute of Scientific and Technical Information of China (English)

    HuangXiwen; ShiFang; 等

    1998-01-01

    The adsorption characteristics of inosine from fermentation solution on anion exchange resin under the condition of different pH,resin type are investigated.Besides,the desorption conditions are studied under different temperature.The adsorption and desorption mechanism are described to obtain the optimum technological condition of inosine extraction.

  18. Kilogram-scale purification of americium by ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Wheelwright, E. J.

    1979-01-01

    Sequential anion and cation exchange processes have been used for the final purification of /sup 241/Am recovered during the reprocessing of aged plutonium metallurgical scrap. Plutonium was removed by absorption of Dowex 1, X-3.5 (30 to 50 mesh) anion exchange resin from 6.5 to 7.5 M HNO/sub 3/ feed solution. Following a water dilution to 0.75 to 1.0 M HNO/sub 3/, americium was absorbed on Dowex 50W, X-8 (50 to 100 mesh) cation exchange resion. Final purification was accomplished by elution of the absorbed band down 3 to 4 successive beds of the same resin, preloaded with Zn/sup 2 +/, with an NH/sub 4/OH buffered chelating agent. The recovery of mixed /sup 241/Am-/sup 243/Am from power reactor reprocessing waste has been demonstrated. Solvent extraction was used to recover a HNO/sub 3/ solution of mixed lanthanides and actinides from waste generated by the reprocessng of 13.5 tons of Shippingport Power Reactor blanket fuel. Sequential cation exchange band-displacement processes were then used to separate americium and curium from the lanthanides and then to separate approx. 60 g of /sup 244/Cm from 1000 g of mixed /sup 241/Am-/sup 243/Am.

  19. Energy exchange via multi-species streaming in laser-driven ion acceleration

    Science.gov (United States)

    King, M.; Gray, R. J.; Powell, H. W.; Capdessus, R.; McKenna, P.

    2017-01-01

    Due to the complex electron dynamics and multiple ion acceleration mechanisms that can take place in the interaction of an ultra-intense laser pulse with a thin foil, it is possible for multiple charged particle populations to overlap in space with varying momentum distributions. In certain scenarios this can drive streaming instabilities such as the relativistic Buneman instability and the ion-ion acoustic instability. The potential for such instabilities to occur are demonstrated using particle-in-cell simulations. It is shown that if a population of ions can be accelerated such that it can propagate through other slowly expanding ion populations, energy exchange can occur via the ion-ion acoustic instability.

  20. Encapsulation of Cs/Sr contaminated clinoptilolite in geopolymers produced from metakaolin

    Energy Technology Data Exchange (ETDEWEB)

    Kuenzel, C., E-mail: c.kuenzel08@imperial.ac.uk [Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom); Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom); Cisneros, J.F. [Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom); Neville, T.P. [Centre for CO_2 Technology, Department of Chemical Engineering, University College London, Gower Street, London WC1E6JE (United Kingdom); Vandeperre, L.J. [Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom); Simons, S.J.R.; Bensted, J. [Centre for CO_2 Technology, Department of Chemical Engineering, University College London, Gower Street, London WC1E6JE (United Kingdom); Cheeseman, C.R. [Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom)

    2015-11-15

    The encapsulation of caesium (Cs) and strontium (Sr) contaminated clinoptilolite in Na and K based metakaolin geopolymers is reported. When Cs or Sr loaded clinoptilolite is mixed with a metakaolin geopolymer paste, the high pH of the activating solution and the high concentration of ions in solution cause ion exchange reactions and dissolution of clinoptilolite with release of Cs and Sr into the geopolymer matrix. The leaching of Cs and Sr from metakaolin-based geopolymer has therefore been investigated. It was found that Na-based geopolymers reduce leaching of Cs compared to K-based geopolymers and the results are in agreement with the hard and soft acids and bases (HSAB) theory. Cs ions are weak Lewis acids and aluminates are a weak Lewis base. During the formation of the geopolymer matrix Cs ions are preferentially bound to aluminate phases and replace Na in the geopolymer structure. Sr uptake by Na-geopolymers is limited to 0.4 mol Sr per mole of Al and any additional Sr is immobilised by the high pH which causes precipitation of Sr as low solubility hydroxide and carbonate phases. There was no evidence of any other phases being formed when Sr or Cs are added to metakaolin geopolymers. - Highlights: • Leaching. • Encapsulation of Cs and Sr. • Nuclear waste. • Clinoptilolite.

  1. MECHANISM OF CESIUM EXCHANGE WITH POTASSIUM TITANIUM HEXACYANOFERRATE

    Institute of Scientific and Technical Information of China (English)

    XuShiping; SunYongxia; 等

    1998-01-01

    The mechanism of cesium exchange on potassium titanium hexacyanoferrate (KTiFC) is described in this paper.The dependence of the exchange rate on temperature,particle granule size,and shaking frequency is studied.The results show that ion exchange process is controlled by liquid film diffusion in granule particle.An exchange reaction occurs mainly between K+ in the exchanger and Cs+ in the solution.

  2. Bactericidal and ammonia removal activity of silver ion-exchanged zeolite.

    Science.gov (United States)

    Krishnani, K K; Zhang, Yu; Xiong, Laj; Yan, Yushan; Boopathy, Raj; Mulchandani, Ashok

    2012-08-01

    The antimicrobial activity of silver-zeolite against Escherichia coli, Vibrio harveyi, Vibrio cholerae and Vibrio parahaemolyticus was examined in liquid medium and agar well diffusion assays. The minimum inhibitory concentration for silver ion-exchanged zeolite against E. coli and V. harveyi was 40 μg/ml, and 50-60 μg/ml for V. cholerae and V. parahaemolyticus. The diameter of the inhibition zones for E. coli, V. harveyi, V. cholerae and V. parahaemolyticus, respectively, increased from 0.5 to 2.3 cm, 0.6 to 2.4 cm, 0.3 to 1.65 cm and 0.3 to 1.7 cm with increasing concentrations of silver ion-exchanged zeolite from 10 to 400 μg. Silver-zeolite removed 20-37% ammonia from aqueous solutions. This study suggests that silver ion-exchanged zeolite could impact disease and environmental management in shrimp aquaculture.

  3. Mathematical modeling of salt-gradient ion-exchange simulated moving bed chromatography for protein separations

    Institute of Scientific and Technical Information of China (English)

    卢建刚

    2004-01-01

    The salt-gradient operation mode used in ion-exchange simulated moving bed chromatography (SMBC) can improve the efficiency of protein separations. A detailed model that takes into account any kind of adsorption/ion-exchange equilibrium, salt gradient, size exclusion, mass transfer resistance, and port periodic switching mechanism, was developed to simulate the complex dynamics. The model predictions were verified by the experimental data on upward and downward gradients for protein separations reported in the literature. All design and operating parameters (number, configuration, length and diameter of columns, particle size, switching period, flow rates of feed, raffinate, desorbent and extract, protein concentrations in feed, different salt concentrations in desorbent and feed) can be chosen correctly by numerical simulation. This model can facilitate the design, operation, optimization, control and scale-up of salt-gradient ion-exchange SMBC for protein separations.

  4. Livestock wastewater treatment by zeolite ion exchange and gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Ryul; Kim, Tak Hyun; Lee, Myun Joo [Radiation Research Center for Industry and Environment, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of)

    2008-01-15

    Livestock wastewater containing high concentrations of organic matters and ammonia-nitrogen has been known as one of the recalcitrant wastewater. It is difficult to treat by conventional wastewater treatment techniques. This study was carried out to evaluate the feasibility of zeolite ion exchange and gamma-ray irradiation treatment of livestock wastewater. The removal efficiencies of SCOD{sub Cr} and NH3-N were significantly enhanced by gamma-ray irradiation after zeolite ion exchange as a pre-treatment. However, the effects of zeolite particle size on the SCOD{sub Cr} and NH{sub 3}-N removal efficiencies were insignificant. These results indicate that the combined process of zeolite ion exchange and gamma-ray irradiation has potential for the treatment of livestock wastewater.

  5. Synthesis, characterization and antimicrobial activity of alkaline ion-exchanged ZnO/bentonite nanocomposites

    Institute of Scientific and Technical Information of China (English)

    Hamideh Pouraboulghasem; Mohammad Ghorbanpour; Razieh Shayegh; Samaneh Lotfiman

    2016-01-01

    Nanocomposites of zinc/bentonite clay were synthesized for use as an antibacterial material by a quick and simple alkaline ion exchange method. The synthesis of zinc doped bentonite nanocomposite was accomplished by placing bentonite in a melting bath of ZnSO4 for 10, 20, 40, 60 and 90 min. The complexes were characterized by XRD, SEM and DRS. XRD analyses and SEM observations confirmed the diffusion of zinc to the clay surfaces. Antibacterial activity tests againstEscherichia coli showed that bentonite did not present any antibacterial properties, but after alkaline ion exchange treatment, inhibition was noted. The highest antibacterial activity was observed with ZnO/bentonite composite alkaline ion exchange for 60 and 90 min. Interestingly, the leaching test indicated that ZnO/bentonite did not present any risk for drinking water treatment.

  6. ELECTRIC REGENERATION METHOD OF ION EXCHANGE RESIN IN THE MIXED BED

    Institute of Scientific and Technical Information of China (English)

    WangFang

    1998-01-01

    In this paper,the self-regeneration process of the mixed resins consisting of cation and anion ion exchangers in the electrolialyser of the packed bed is analyzed,and an electric regeneration method is put forward to supply the desalinated water by mixed bed.The electric regeneration technology is a new one used for regeneration of the exhausted ion exchangers in the mixed bed,instead of the traditional regenerating process by using acid and alkali liquor.Electric energy is consumed to regenerate the ion exchangers loaded by salts from water treatment without any chemicals-acid and alkali.The advantage of the electric regeneration process exhibited convenient operation,no discharge any waste,and therefore no pollution to the receiving water body and the environmental ground.

  7. Influence of anodic surface treatment of activated carbon on adsorption and ion exchange properties

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.J.; Kim, K.D.

    1999-10-01

    The effect of anodic surface treatment of activated carbon on adsorption and ion exchange characteristics was investigated in the condition of 35 wt% NaOH electrolyte for 60 s. The acid and base values were determined by a titration technique, and surface and pore structures were studied in terms of BET volumetric measurement with N{sub 2} adsorption. The ion exchange capacity of the anodized activated carbons was characterized by a dry weight capacity technique. It was observed that an increase in current intensity leads to an increase in the surface functional groups of activated carbons, resulting in increasing pH, acid-base values, and anion-cation exchange capacities, without significant change of surface and pore structures (i.e., specific surface area, total pore volume, micropore volume, and average pore diameter). Also, anodically treated activated carbons are more effectively evaluated on the base value or cation exchange capacity than on the oppose properties in this electrolytic system.

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

    OpenAIRE

    Alguacil,Francisco José; Alonso Gámez, Manuel; Lozano, Kuis Javier

    2004-01-01

    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, chro...

  9. Electrochemical Ion-Exchange Regeneration and Fluidized Bed Crystallization for Zero-Liquid-Discharge Water Softening.

    Science.gov (United States)

    Chen, Yingying; Davis, Jake R; Nguyen, Chi H; Baygents, James C; Farrell, James

    2016-06-01

    This research investigated the use of an electrochemical system for regenerating ion-exchange media and for promoting the crystallization of hardness minerals in a fluidized bed crystallization reactor (FBCR). The closed-loop process eliminates the creation of waste brine solutions that are normally produced when regenerating ion-exchange media. A bipolar membrane electrodialysis stack was used to generate acids and bases from 100 mM salt solutions. The acid was used to regenerate weak acid cation (WAC) ion-exchange media used for water softening. The base solutions were used to absorb CO2 gas and to provide a source of alkalinity for removing noncarbonate hardness by WAC media operated in H(+) form. The base solutions were also used to promote the crystallization of CaCO3 and Mg(OH)2 in a FBCR. The overall process removes hardness ions from the water being softened and replaces them with H(+) ions, slightly decreasing the pH value of the softened water. The current utilization efficiency for acid and base production was ∼75% over the operational range of interest, and the energy costs for producing acids and bases were an order of magnitude lower than the costs for purchasing acid and base in bulk quantities. Ion balances indicate that the closed-loop system will accumulate SO4(2-), Cl(-), and alkali metal ions. Acid and base balances indicate that for a typical water, small amounts of base will be accumulated.

  10. Metal ion exchange process by natural and modified clinoptilolite

    Energy Technology Data Exchange (ETDEWEB)

    Athanasiadis, K.; Petter, C.; Hilliges, R.; Helmreich, B.; Wilderer, P.A. [TU Muenchen (Germany). Lehrstuhl fuer Wasserguete- und Abfallwirtschaft

    2003-07-01

    Clinoptilolite, one of the most frequently studied natural zeolites, was shown to have high selectivity for certain heavy metals such as lead, cadmium and nickel. The aim of this study is to present equilibrium and kinetic data for Pb{sup 2+}, Cu{sup 2+} and Zn{sup 2+} exchange on natural and modified clinoptilolite for two different pH values. Selectivity series and kinetic data from these three heavy metals are presented. (orig.)

  11. Technical note: Efficiency of total demineralization and ion-exchange column for DNA extraction from bone.

    Science.gov (United States)

    Seo, Seung Bum; Zhang, Aihua; Kim, Hye Yeon; Yi, Jin A; Lee, Hye Young; Shin, Dong Hoon; Lee, Soong Deok

    2010-01-01

    We investigated whether a combination of recently introduced methods, total demineralization and ion-exchange columns, would increase DNA recovery from old bone. Ten bone samples taken after a burial period of approximately 60 years were used in this study. Bone powder was digested using total or incomplete demineralization. DNA was extracted by the standard organic method. The DNA extract was purified with ion-exchange columns or QIAquick spin columns. The efficiency of different DNA extraction methods was compared in terms of DNA concentration, inhibitors generated by real-time PCR, and conventional STR typing results. The mean DNA concentration using the total demineralization method is approximately 3 times higher than that using the incomplete demineralization method. For DNA purification, the method using QIAquick spin columns appeared to yield approximately double the DNA than the method using ion-exchange columns. Furthermore, 2 out of 10 samples showed higher levels of inhibition with C(T) values of IPC > or =30 cycles when using only ion-exchange columns. In STR results, total demineralization yielded more locus profiles by 4.2 loci than incomplete demineralization, and QIAquick spin columns also yielded more locus profiles by 3.5 loci than ion-exchange columns. Total demineralization of bone powder significantly increased DNA yield and improved STR typing results. However, the use of ion-exchange columns was not efficient when compared with the method using QIAquick spin columns. It is suggested that the combination of total demineralization and QIAquick spin columns lead to greatly improved STR typing results.

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

    Directory of Open Access Journals (Sweden)

    Abdel E. Ghaly

    2008-01-01

    Full Text Available 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 (CEC was 40 cmoL kg-1 which was very suitable for ion-exchange process. A 500 g sample of saline sludge (containing CaCl2:MgCl2:NaCl ratio as 1:1.16:36.61 was washed using demineralized water in a mixed reactor and the sludge was allowed to settle for 36 h. The optimal number of washes was determined to be two washes with an overall salt removal efficiency of 94.47%. The treated sludge contained 515 mg salt kg-1 sludge (or 0.05% w w-1 and was suitable for agricultural application. The washwater was passed through a Mountain Stronach zeolite (chabazite based ion-exchange column for salt reduction. The sodium salt removal efficiency was 75.34%. This was increased to 99.79% when using two ion-exchange columns. The Ca and Mg ions were under regulatory limits and required no further treatment. The final salt concentration in the wash water was 314.0 mg L-1 which was below the limits established by the Canadian Guidelines. For complete removal of total salts, a series of ion-exchange columns with different zeolites (for removal of NaCl, MgCl2 and CaCl2 will be required.

  13. Gold Loading on Ion Exchange Resins in Non-Ammoniacal Resin-Solution Systems

    OpenAIRE

    Abrar Muslim

    2010-01-01

    The loading of gold using strong base anion exchange resin in non-ammoniac resin-solution (NARS) systems has been studied. The loading of gold onto ion exchange resins is affected by polythionate concentration, and trithionate can be used as the baseline in the system. The results also show that resin capacity on gold loading increases due to the increase in the equilibrium thiosulfate concentration in the NARS system. Gold loading performances show the need of optimization the equilibrium co...

  14. Disease-associated changes in the expression of ion channels, ion receptors, ion exchangers and Ca(2+)-handling proteins in heart hypertrophy.

    Science.gov (United States)

    Zwadlo, Carolin; Borlak, Jürgen

    2005-09-15

    The molecular pathology of cardiac hypertrophy is multifactorial with transcript regulation of ion channels, ion exchangers and Ca(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(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 ion exchangers (Atp1A1, NCX-1, SERCA2a), ion channels (L-type Ca(2+)-channel, K(ir)3.4, Na(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 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. Relation between stabilization energy, crystal field coefficient and themagnetic exchange interaction for Tb3+ ion

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiangmu; MA Wenjuan; CUI Shuwen; WANG Lihua

    2006-01-01

    Based on a single ion model, Hamiltonian of the simplest form about magnetocrystalline anisotropy for Tb3+ ion was solved by using the numerical method. The relation between the stabilization energy, crystal field coefficient B20 and the magnetic exchange interaction was studied as temperature approaches to 0K. The results show that the stabilization energy contributed by Tb3+ is linear with crystal field coefficient B20 approximately, but it is insensitive to the change of magnetic exchange interaction for the strong magnetic substancessuch as TbCo5, Tb2Co17 and Tb2Fe14B compounds.

  16. Processing of indium (III) solutions via ion exchange with Lewatit K-2621 resin

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Diaz-Pavon, A.; Cerpa, A.; Alguacil, F. J.

    2014-10-01

    The processing of indium(III)-hydrochloric acid solutions by the cationic ion exchange Lewatit K-2621 resin has been investigated. The influence of several variables such as the hydrochloric acid and metal concentrations in the aqueous solution and the variation of the amount of resin added has been studied. Moreover, a kinetic study performed in the uptake of indium(III) by Lewatit K-2621, shows that either the film-diffusion and the particle-diffusion models fit the ion exchange process onto the resin, depending upon the initial metal concentration in the aqueous solution. The loaded resin could be eluted by HCl solutions at 20 degree centigrade. (Author)

  17. Lability of heavy metal species in aquatic humic substances characterized by ion exchange with cellulose phosphate.

    Science.gov (United States)

    Rocha, J C; Toscano, I A; Burba, P

    1997-01-01

    Labile metal species in aquatic humic substances (HSs) were characterized by ion exchange on cellulose phosphate (CellPhos) by applying an optimized batch procedure. The HSs investigated were pre-extracted from humic-rich waters by ultrafiltration and a resin XAD 8 procedure. The HS-metal species studied were formed by complexation with Cd(II), Ni(II), Cu(II), Mn(II) and Pb(II) as a function of time and the ratio ions to HSs. The kinetics and reaction order of this exchange process were studied. At the beginning ( Pb > Mn > Ni > Cd. The required metal determinations were carried out by atomic absorption spectrometry.

  18. Features of the sorption of phenylalanine by profiled ion-exchange membranes

    Science.gov (United States)

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

    2016-10-01

    Features of the equilibrium sorption of phenylalanine from neutral media by profiled ion-exchange membranes in a wide range of concentrations is studied under static conditions. The mechanism of phenylalanine sorption by ion-exchange membranes with profiled and smooth surfaces is discussed. It is shown that phenylalanine sorption is accompanied by the formation of spatial associative structures of the aminoacid in an external equilibrium solution, and in a solution of the membrane's pore spaces or on its surface. The increased sorption capacity of the profiled membranes is explained by features of the microstructure of their surface and volume.

  19. Nanofiltration: ion exchange system for effective surfactant removal from water solutions

    Directory of Open Access Journals (Sweden)

    I. Kowalska

    2014-12-01

    Full Text Available A system combining nanofiltration and ion exchange for highly effective separation of anionic surfactant from water solutions was proposed. The subjects of the study were nanofiltration polyethersulfone membranes and ion-exchange resins differing in type and structure. The quality of the treated solution was affected by numerous parameters, such as quality of the feed solution, membrane cut-off, resin type, dose and the solution contact time with the resin. A properly designed purification system made it possible to reduce the concentration of anionic surfactant below 1 mg L-1 from feed solutions containing surfactant in concentrations above the CMC value.

  20. Mass and Heat Transfer in Ion-Exchange Membranes Applicable to Solid Polymer Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Otteroey, M.

    1996-04-01

    In this doctoral thesis, an improved emf method for determination of transference numbers of two counter ions in ion-exchange membranes is presented. Transference numbers were obtained as a continuous function of the composition. The method avoids problems with diffusion by using a stack of membranes. Water transference coefficients in ion-exchange membranes is discussed and reversible and irreversible water transfer is studied by emf methods. Efforts were made to get data relevant to the solid polymer fuel cell. The results support the findings of other researchers that the reversible water transfer is lower than earlier predicted. A chapter on the conductivity of ion-exchange membranes establishes a method to separate the very thin liquid layers surrounding the membranes in a stack. Using the method it was found that the conductivity is obtained with high accuracy and that the liquid layer in a membrane stack can contribute significantly to the total measured resistance. A four point impedance method was tested to measure the conductivity of membranes under fuel cell conditions. Finally, there is a discussion of reversible heat effects and heat transfer in ion-exchange membranes. 155 refs., 45 figs., 13 tabs.

  1. Patchiness of ion-exchanged mica revealed by DNA binding dynamics at short length scales

    Science.gov (United States)

    Billingsley, D. J.; Lee, A. J.; Johansson, N. A. B.; Walton, A.; Stanger, L.; Crampton, N.; Bonass, W. A.; Thomson, N. H.

    2014-01-01

    The binding of double-stranded (ds) DNA to mica can be controlled through ion-exchanging the mica with divalent cations. Measurements of the end-to-end distance of linear DNA molecules discriminate whether the binding mechanism occurs through 2D surface equilibration or kinetic trapping. A range of linear dsDNA fragments have been used to investigate length dependences of binding. Mica, ion-exchanged with Ni(II) usually gives rise to kinetically trapped DNA molecules, however, short linear fragments (ion-exchanged mica is heterogeneous, and contains patches or domains, separating different ionic species. These results correlate with imaging of dsDNA under aqueous buffer on Ni(II)-mica and indicate that binding domains are of the order of 100 nm in diameter. Shorter DNA fragments behave intermediate to the two extreme cases of 2D equilibration and kinetic trapping. Increasing the incubation time of Ni(II) on mica, from minutes to hours, brings the conformations of the shorter DNA fragments closer to the theoretical value for kinetic trapping, indicating that long timescale kinetics play a role in ion-exchange. X-ray photoelectron spectroscopy (XPS) was used to confirm that the relative abundance of Ni(II) ions on the mica surface increases with time. These findings can be used to enhance spatial control of binding of DNA to inorganic surfaces with a view to patterning high densities arrays.

  2. Mass and Heat Transfer in Ion-Exchange Membranes Applicable to Solid Polymer Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Otteroey, M.

    1996-04-01

    In this doctoral thesis, an improved emf method for determination of transference numbers of two counter ions in ion-exchange membranes is presented. Transference numbers were obtained as a continuous function of the composition. The method avoids problems with diffusion by using a stack of membranes. Water transference coefficients in ion-exchange membranes is discussed and reversible and irreversible water transfer is studied by emf methods. Efforts were made to get data relevant to the solid polymer fuel cell. The results support the findings of other researchers that the reversible water transfer is lower than earlier predicted. A chapter on the conductivity of ion-exchange membranes establishes a method to separate the very thin liquid layers surrounding the membranes in a stack. Using the method it was found that the conductivity is obtained with high accuracy and that the liquid layer in a membrane stack can contribute significantly to the total measured resistance. A four point impedance method was tested to measure the conductivity of membranes under fuel cell conditions. Finally, there is a discussion of reversible heat effects and heat transfer in ion-exchange membranes. 155 refs., 45 figs., 13 tabs.

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

    CERN Document Server

    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...

  4. Effects of swift argon-ion irradiation on the proton-exchanged LiNbO3 crystal

    Science.gov (United States)

    Huang, Qing; Liu, Peng; Liu, Tao; Guo, Sha-Sha; Wang, Xue-Lin

    2012-05-01

    A proton-exchanged LiNbO3 crystal was subjected to 70-MeV argon-ion irradiation. The lattice damage was investigated by the Rutherford backscattering and channeling technique. It was found that the lattice disorder induced by the proton exchange process was partially recovered and the proton-exchanged layer was broadened. It indicated that the lithium ions underneath the initial proton-exchanged layer migrated to the surface during the swift argon-ion irradiation and supplemented the lack of lithium ions in the initial proton-exchanged layer. This effect was ascribed to the great electronic energy deposition and relaxation. The swift argon-ion irradiation induced an increase in extraordinary refractive index and formed another waveguide structure beneath the proton-exchanged waveguide.

  5. Effects of swift argon-ion irradiation on the proton-exchanged LiNbO3 crystal

    Institute of Scientific and Technical Information of China (English)

    Huang Qing; Liu Peng; Liu Tao; Guo Sha-Sha; Wang Xue-Lin

    2012-01-01

    A proton-exchanged LiNbO3 crystal was subjected to 70-MeV argon-ion irradiation.The lattice damage was investigated by the Rutherford backscattering and channeling technique.It was found that the lattice disorder induced by the proton exchange process was partially recovered and the proton-exchanged layer was broadened.It indicated that the lithium ions underneath the initial proton-exchanged layer migrated to the surface during the swift argon-ion irradiation and supplemented the lack of lithium ions in the initial proton-exchanged layer.This effect was ascribed to the great electronic energy deposition and relaxation.The swift argon-ion irradiation induced an increase in extraordinary refractive index and formed another waveguide structure beneath the proton-exchanged waveguide.

  6. Modified DIX model for ion-exchange equilibrium of L-phenylalanine on a strong cation-exchange resin☆

    Institute of Scientific and Technical Information of China (English)

    Jinglan Wu; Pengfei Jiao; Wei Zhuang; Jingwei Zhou; Hanjie Ying

    2016-01-01

    L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of L-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of L-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimental y and theoretical y. A modified Donnan ion-exchange (DIX) model, which takes the activity into account, was established to predict the uptake of L-phenyl-alanine at various solution pH values. The model parameters including selectivity and mean activity coefficient in the resin phase are presented. The modified DIX model is in good agreement with the experimental data. The optimum operating pH value of 2.0, with the highest L-phenylalanine uptake on the resin, is predicted by the model. This basic information combined with the general mass transfer model wil lay the foundation for the prediction of dynamic behavior of fixed bed separation process.

  7. Improved durability of proton exchange membrane fuel cells by introducing Sn (IV) oxide into electrodes using an ion exchange method

    Science.gov (United States)

    Poulsen, M. G.; Larsen, M. J.; Andersen, S. M.

    2017-03-01

    Electrodes of Proton Exchange Membrane Fuel Cells (PEMFCs), consisting of catalyst-coated gas diffusion layers, were subjected to an optimized ion exchange procedure, in which tin (IV) oxide (SnO2) nanoparticles were introduced into them. Both methanol and sulfuric acid were tested as ion exchange solvents. SnO2 has previously been shown to exhibit radical scavenging abilities towards radicals inside the electrocatalyst layers. Its presence inside the electrodes was confirmed using X-ray photoelectron spectroscopy and X-ray fluorescence. After exposure to an accelerated stress test in a three-electrode setup, the electrodes containing SnO2 were found to have retained approximately 73.0% of their original Pt, while only 53.2% was retained in electrodes treated identically, but without Sn. Similarly, the SnO2-treated electrodes also experienced a smaller loss in electrochemical surface area in comparison to before the accelerated stress test. A membrane electrode assembly (MEA) constructed with a SnO2-containing anode was evaluated over 500 h. The results showed remarkably reduced OCV decay rate and end of test hydrogen crossover compared to the control MEA, indicating that SnO2 aids in impeding membrane thinning and pinhole formation. The results point toward a positive effect of SnO2 on fuel cell durability, by reducing the degradation of the membrane as well as of the ionomer in the electrocatalyst layer.

  8. Effect of diffusion potential, osmosis and ion-exchange on transdermal drug delivery: theory and experiments.

    Science.gov (United States)

    Hirvonen, J; Murtomäki, L; Kontturi, K

    1998-12-04

    Equations expressing the effect of the diffusion potential on the trace ion transfer across a porous charged membrane have been derived. These equations have been tested with experiments with human cadaver skin. The transfer of sotalol and salicylate was measured varying the salt (NaCl) concentration in the donor and receiver compartments. It appears that osmotic pressure and ion-exchange make a significant contribution to the flux enhancement by the diffusion potential.

  9. Acid Extraction - Ion Exchange Recovery of Cinchona Alkaloids Process and Plant Development

    Science.gov (United States)

    1945-06-08

    farther and farther into the almost impenetrable rain forests of the Andes in search of drug- bearing bark. b. Labor and Transportation. In these...a certain percentage of the ion exchanger still bearing its hydrogen ion charge. As long as this situation exists, a certain amount of COp will...extraction medium. Hence, the contact time need be no greater than that re- quired to soften and disintegrate the gummy contents of the cell, plus

  10. POTENTIOMETRIC BEHAVIOR OF CHELATING ION EXCHANGE RESIN IN WATER AND IN ETHANOL—WATER MIXTURES

    Institute of Scientific and Technical Information of China (English)

    DOUHuiyuan; WANGChangshou; 等

    1993-01-01

    The potentiometric behavior of the chelating ion exchange resin D751 containing iminodiacetic acid groups has been studied at 25℃ by batch titration with alkali and acid in water and in ethanol-water mixture solvent.The titrtion curves,the amount of chemically bound counter-ions and invasive electrolytes in the resin phase,and the solvent contents the resin have been investigated.

  11. Nitroguanidine Wastewater Pollution Control Technology: Phase III. Ion Exchange and Carbon Adsorption Treatment

    Science.gov (United States)

    1984-03-01

    SD are synthetic cross-linked resins provided as moist spherical beads nominally of 50 percent water content. The clinoptilolite was supplied presized...Na+ i3 provided by a resin (either naturally occurring or synthetic ). Usually, the resin is prepared in a fixed-bed column, and hard water ion is...these :.ons as well as NQ. I/’ I . , I * MATERIALS AND METHODS RESINS AND CARBONS Three ion-exchange materials were studied: clinoptilolite , an

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Effect of formaldehyde on Cu(II) removal from synthetic complexed solutions by ion exchange.

    Science.gov (United States)

    Juang, Ruey-Shin; Lin, Su-Hsia; Kao, Hsiang-Chien; Theng, Ming-Huei

    2005-06-01

    The effect of formaldehyde (HCHO) on the ion exchange of Cu(II) from an equimolar EDTA (ethylenediaminetetraacetic acid, H(4)L) solution with a strong-base Amberlite IRA-400 resin was studied. Experiments were conducted as a function of the initial concentration of Cu(II) (0.5-10 mM), solution pH (1.0-6.0), HCHO concentration (0-6 vol%), and temperature (15-35 degrees C). It was shown that the amount of exchange of Cu(II), which exists in the form of complexed anions CuL(2-), increased with increasing solution pH and reached a plateau at an equilibrium pH (pH(e)) of 3.5. However, the amount of exchange decreased with increasing HCHO concentration up to 3 vol% but then slightly decreased with a further increase in HCHO concentration. Such effect of added HCHO was determined by the following two factors: the competitive exchange of HCOO(-) anions and the enhanced exchange of Cu(I) in the form of complexed anions CuL(3-). The exchange isotherm obtained at a fixed pH(e) could be well described by the Langmuir equation. The isosteric enthalpy change for the present ion exchange process was also evaluated and discussed.

  14. Molecular CsF 5 and CsF 2 +

    KAUST Repository

    Rogachev, Andrey Yu.

    2015-06-03

    D5h star-like CsF5, formally isoelectronic with known XeF5− ion, is computed to be a local minimum on the potential energy surface of CsF5, surrounded by reasonably large activation energies for its exothermic decomposition to CsF+2 F2, or to CsF3 (three isomeric forms)+F2, or for rearrangement to a significantly more stable isomer, a classical Cs+ complex of F5−. Similarly the CsF2+ ion is computed to be metastable in two isomeric forms. In the more symmetrical structures of these molecules there is definite involvement in bonding of the formally core 5p levels of Cs.

  15. Ion exchanger in the brain: Quantitative analysis of perineuronally fixed anionic binding sites suggests diffusion barriers with ion sorting properties

    Science.gov (United States)

    Morawski, Markus; Reinert, Tilo; Meyer-Klaucke, Wolfram; Wagner, Friedrich E.; Tröger, Wolfgang; Reinert, Anja; Jäger, Carsten; Brückner, Gert; Arendt, Thomas

    2015-12-01

    Perineuronal nets (PNs) are a specialized form of brain extracellular matrix, consisting of negatively charged glycosaminoglycans, glycoproteins and proteoglycans in the direct microenvironment of neurons. Still, locally immobilized charges in the tissue have not been accessible so far to direct observations and quantifications. Here, we present a new approach to visualize and quantify fixed charge-densities on brain slices using a focused proton-beam microprobe in combination with ionic metallic probes. For the first time, we can provide quantitative data on the distribution and net amount of pericellularly fixed charge-densities, which, determined at 0.4-0.5 M, is much higher than previously assumed. PNs, thus, represent an immobilized ion exchanger with ion sorting properties high enough to partition mobile ions in accord with Donnan-equilibrium. We propose that fixed charge-densities in the brain are involved in regulating ion mobility, the volume fraction of extracellular space and the viscosity of matrix components.

  16. Charge-exchange Induced Modulation of the Heliosheath Ion Distribution Downstream of the Termination Shock

    Science.gov (United States)

    Fahr, H. J.; Fichtner, H.; Scherer, K.

    2015-12-01

    We consider the evolution of the solar wind ion distribution function alongthe plasma flow downstream from the termination shock induced by chargeexchange processes with cold interstellar H-atoms. We start from a kineticphase space transport equation valid in the bulk frame of the plasma flowthat takes into account convective changes, cooling processes, energydiffusion and ion injection, and describes solar wind and pick-up ionsas a co-moving, isotropic, joint ion population. From this kinetic transportequation one can ascend to an equation for the pressure moment of the iondistribution function, a so-called pressure transport equation, describingthe evolution of the ion pressure in the comoving rest frame. Assuming thatthe local ion distribution can be represented by an adequate kappa functionwith a kappa parameter that varies with the streamline coordinate, weobtain an ordinary differential equation for kappa as function of thestreamline coordinate s. With this result then we gain the heliosheath iondistribution function downstream of the termination shock. The latter thencan be used to predict the Voyager-2 measured moments of the distributionfunction like ion density and ion temperature, and it can also be used topredict spectral fluxes of ENA`s originating from these ions and registeredby IBEX-Hi and IBEX-Lo.We especially analyse the solar wind ion temperature decreasemeasured by Voyager-2 between the years 2008 to 2011 and try to explain itas a charge-exchange induced cooling of the ion distribution function duringthe associated ion convection period.

  17. Development of a new analysis method evaluating adsorption energies for the respective ion-exchanged sites on alkali-metal ion-exchanged ZSM-5 utilizing CO as a probe molecule: IR-spectroscopic and calorimetric studies combined with a DFT method.

    Science.gov (United States)

    Kumashiro, Ryotaro; Fujie, Kazuhiko; Kondo, Aki; Mori, Toshinori; Nagao, Mahiko; Kobayashi, Hisayoshi; Kuroda, Yasushige

    2009-07-07

    For alkali-metal ion-exchanged ZSM-5 zeolites (MZSM-5; M: Li, Na, K, Rb, Cs) the analysis of ion-exchangeable sites was performed by means of a combined method based on IR spectroscopic and calorimetric measurements using CO as the probe molecule. The heat of adsorption of CO was found to be correlated with an IR frequency of stretching vibration of C-O in the adsorbed species. It was revealed that there exists at least two types of sites capable of ion-exchanging; for the lithium ion-exchanged ZSM-5 (LiZSM-5) CO adsorption on each type of site is evaluated to give a set of IR bands and heats of adsorption, 2195 cm(-1) and 49 kJ mol(-1), 2185 cm(-1) and 39 kJ mol(-1) with the aid of the newly developed method utilizing the data obtained from a combined microcalorimetric and IR-spectroscopic study. Such types of data were also obtained for Na- and K-ion-exchanged ZSM-5 samples. Furthermore, a linear relationship between the differential heat of adsorption (q(diff)) evaluated and the shift of wavenumber of the C-O stretching vibration from that of a gaseous CO molecule (Deltanu) was established for the systems of MZSM-5-CO, and the bonding nature of the CO molecule with each site can be explained in terms of the electrostatic force. The model of each adsorption site was also examined by the quantum calculation method (density functional theory: DFT). The trends obtained from the experimental data may be substantially supported by the calculation method even adopting a model as simple as the ZSM-5-type zeolite: the composition of MAlSi(4)O(4)H(12).

  18. Pyrolysis of spent ion exchange resins; Die Pyrolyse von verbrauchten Ionentauscherharzen

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-07-15

    Ion exchangers are employed in all nuclear power plants with water loops to remove radionuclides from the primary coolant. Cation and anion exchangers are used as coarse-grained spherical resins in pressurized water reactors and as finely ground powder resins in boiling water reactors. In new plants there is a trend to exploit all possibilities of avoiding contaminated liquids and, should solutions occur nevertheless, clean them by ion exchange to such an extent that they can be disposed of as non-radioactive waste. This means less use of evaporator facilities or even giving them up altogether. Regeneration, which is possible in principle, is hardly employed at all. As a rule, ion exchangers consist of cross-linked polystyrene. As no use is made of regeneration in nuclear power plants, unlike conventional technology, the material must be disposed of as radioactive waste. In this connection, it is important to bear in mind that spent ion exchangers are too moist for direct disposal and are made up of inorganic matter. Consequently, a process is needed which reduces volume, produces an inert or mineralized product, works at temperatures not exceeding approx. 600 C, and can be run in a simple plant. NUKEM further developed a pyrolysis technique known from other technical applications. These ion exchangers can be decomposed by pyrolysis very effectively; the product is inert and chemically resistant. No additives are needed. The entire radioactivity inventory remains in the pyrolysate. The pyrolysate is a flowable solid. This makes it easy to handle and allows it to be compacted or cemented, depending on interim and repository storage conditions and on the activity inventory. (orig.)

  19. Direct Encapsulation of Spent Ion-exchange Resins at the Dukovany Nuclear Power Plant, Czech Republic - 12367

    Energy Technology Data Exchange (ETDEWEB)

    Fletcher, Paul [AMEC Nuclear UK, Knutsford (United Kingdom); Rima, Steve [AMEC USA (United States)

    2012-07-01

    At the Dukovany Nuclear Power Plant there are large amounts of spent ion exchange resins contained within storage tanks. These resins are a product of the operation of an Active Water Purification System within the Power Plant. Activity levels of the resins are in the range of 105 to 10{sup 6} Bq/l and the main isotopes present are Co-60, Cs-137, Mn-54 and Ag-110m. In order to maintain storage tank availability throughout the planned lifetime of the Power Plant these resins must be removed and disposed of safely. The storage tanks do not have an effective retrieval route for the resins and the installed agitation system is inoperable. A proven system for retrieving and directly encapsulating these resins to a standard required for the Czech repository is described, together with an overview of operational performance. Experience gained from this and other projects has highlighted some common challenges relating to the treatment of ion-exchange resins and sludges. There are common approaches that can assist in overcoming these challenges. 1. Transport resin / sludge type waste over as short a distance as possible to avoid issues with line plugging. 2. Transport these wastes once and once only wherever possible. 3. Try to keep the treatment process as simple as possible. With sludge or resin handling equipment consider the physical properties foremost - radiological issues can be addressed within any subsequent design. 4. Consider the use of dry-mix technologies. This avoids the requirement for expensive and complicated grouting plant. 5. Avoid the use of make up water for transport purposes if at all possible - it introduces secondary waste that needs to be treated at additional cost. 6. Consider alternative disposal techniques. SIAL{sup R} is AMEC's preferred technology as we developed it and understand it well - additionally the waste loading factors are much higher than for cement. 7. Consider final waste volumes when selecting the disposal technique

  20. Commercial Ion Exchange Resin Vitrification in Borosilicate Glass

    Energy Technology Data Exchange (ETDEWEB)

    Cicero-Herman, C.A.; Workman, P. [Westinghouse Savannah River Co., Aiken, SC (United States); Poole, K.; Erich, D.; Harden, J. [Clemson Environmental Technologies Laboratory, Anderson, SC (United States)

    1998-05-01

    Bench-scale studies were performed to determine the feasibility of vitrification treatment of six resins representative of those used in the commercial nuclear industry. Each resin was successfully immobilized using the same proprietary borosilicate glass formulation. Waste loadings varied from 38 to 70 g of resin/100 g of glass produced depending on the particular resin, with volume reductions of 28 percent to 68 percent. The bench-scale results were used to perform a melter demonstration with one of the resins at the Clemson Environmental Technologies Laboratory (CETL). The resin used was a weakly acidic meth acrylic cation exchange resin. The vitrification process utilized represented a approximately 64 percent volume reduction. Glass characterization, radionuclide retention, offgas analyses, and system compatibility results will be discussed in this paper.

  1. Modification of a montmorillonite-illite clay using alkaline hydrothermal treatment and its application for the removal of aqueous Cs+ ions.

    Science.gov (United States)

    Oztop, B; Shahwan, T

    2006-03-15

    A montmorillonite-illite clay was modified using alkaline hydrothermal treatment (reflux method) and applied to the removal of aqueous Cs+ ions. The alkaline solutions were prepared by dissolving NaOH in seawater and in distilled water, and the effect of the two alkaline media on the sorption capacities of the modified clay was discussed. The modified materials were characterized using XRD, SEM/EDS, and FTIR. As a result of the modification, the original mineral was partially transformed into a zeolitic material with spherical morphology. The results showed that the modification improved the Cs+ uptake capacity of the starting clay, with the clay modified in distilled water medium demonstrating higher sorption capacity. The sorption data were adequately described using the Freundlich and Dubinin-Radushkevich isotherm models.

  2. GeS2-In2S3-CsI Chalcogenide Glasses Doped with Rare Earth Ions for Near- and Mid-IR Luminescence.

    Science.gov (United States)

    Li, Legang; Bian, Junyi; Jiao, Qing; Liu, Zijun; Dai, Shixun; Lin, Changgui

    2016-11-21

    Chalcogenide glass has been considered as a promising host for the potential laser gain and amplifier media operating in near- and mid-IR spectral region. In this work, the IR luminescence spectra of rare earth ions (Tm(3+), Er(3+), and Dy(3+)) doped 65GeS2-25In2S3-10CsI chalcogenide glasses were measured under the excitation of an 808 nm laser diode. To the best of our knowledge, it firstly provides the luminescence spectra of a full near- and mid-IR spectral range from 1 to 4 μm in rare earth ions doped chalcogenide glasses. The results of absorption spectra, luminescence spectra, and fluorescence decay curves were obtained in these samples with singly-, co- and triply-doping behaviors of Tm(3+), Er(3+), and Dy(3+) ions. In order to search possible efficient IR emissions, the luminescence behavior was investigated specifically with the variation of doping behaviors and dopant ions, especially in the samples co- and triply-doped active ions. The results suggest that favorable near- and mid-IR luminescence of rare earth ions can be further modified in chalcogenide glasses through an elaborated design of doping behavior and optically active ions.

  3. GeS2–In2S3–CsI Chalcogenide Glasses Doped with Rare Earth Ions for Near- and Mid-IR Luminescence

    Science.gov (United States)

    Li, Legang; Bian, Junyi; Jiao, Qing; Liu, Zijun; Dai, Shixun; Lin, Changgui

    2016-11-01

    Chalcogenide glass has been considered as a promising host for the potential laser gain and amplifier media operating in near- and mid-IR spectral region. In this work, the IR luminescence spectra of rare earth ions (Tm3+, Er3+, and Dy3+) doped 65GeS2–25In2S3–10CsI chalcogenide glasses were measured under the excitation of an 808 nm laser diode. To the best of our knowledge, it firstly provides the luminescence spectra of a full near- and mid-IR spectral range from 1 to 4 μm in rare earth ions doped chalcogenide glasses. The results of absorption spectra, luminescence spectra, and fluorescence decay curves were obtained in these samples with singly-, co- and triply-doping behaviors of Tm3+, Er3+, and Dy3+ ions. In order to search possible efficient IR emissions, the luminescence behavior was investigated specifically with the variation of doping behaviors and dopant ions, especially in the samples co- and triply-doped active ions. The results suggest that favorable near- and mid-IR luminescence of rare earth ions can be further modified in chalcogenide glasses through an elaborated design of doping behavior and optically active ions.

  4. Beam propagation in Cu +-Na + ion exchange channel waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Villegas Vicencio, L. J.; Khomenko, A. V.; Salazar, D.; Marquez, H. [Centro de Investigacion Cientifica y de Educacion Superior de Ensenada, Baja California (Mexico); Porte, H. [Universite de Franche-Comte, UFR des Sciences et Techniques, Besancon, Cedex (France)

    2001-06-01

    We employ the fast Fourier transform beam propagation method to simulate the propagation of light in graded index channel waveguides, these have been obtained by solid state diffusion of copper ions in soda-lime glass substrates. Longitudinal propagation has been simulated, the input light beam has a gaussian profile. Two cases have been analyzed, in the first, the Gaussian beam is collinear center to center with respect to waveguide; in the second, a small lateral offset and angular tilt have been introduced. Modal beating and bending effects have been founded. We have proven the validity of our numerical results in detailed comparison with experimental data. [Spanish] Se ha empleado el metodo de propagacion de haces por la transformada rapida de Fourier para simular la propagacion de la luz en guias de onda de indice de gradiente. Estas han sido fabricadas por difusion de iones de cobre en estado solido en substratos de vidrios sodicos-calcicos. Se han simulado dos casos, el primero, el perfil de luz de entrada, que es gaussiano, es colineal centro a centro respecto al centro de la guia de ondas: el segundo, se ha dado un pequeno corrimiento lateral y una inclinacion angular. Como consecuencia de los casos anteriores se ha observado efectos de batimiento modal. Los resultados de la simulacion se han validado con resultados experimentales.

  5. THE TESTS AND MECHANISM ABOUT SODIUM IONS FROM AN ANION EXCHANGER

    Institute of Scientific and Technical Information of China (English)

    ZhuXingbao; YuJinchun; 等

    1996-01-01

    There exists a universal phenomena that sodium ions are leaked from the strong basic anion exdchanger in operation,which has been puzzling the researchers working in the field of water treatment for years.It is well known that the leakage of sodium ions will seriously affect the pruity of effluent.On the basis of lots of laboratory and industrial experiments,the mechanism of the sodium ions leaked from an anion exchanger has been preliminarily made out and some new chemical reaction equations as well as some improving measures have been put forward in this article.

  6. Synthesis and Characterization of Templated Ion Exchange Resins for the Selective Complexation of Actinide Ions

    Energy Technology Data Exchange (ETDEWEB)

    Uy, O. Manual

    2001-03-01

    The purpose of this research is to develop a polymeric extractant for the selective complexation of uranyl ions (and subsequently other actinyl and actinide ions) from aqueous solutions (lakes, streams, waste tanks and even body fluids). Chemical insights into what makes a good complexation site will be used to synthesize reagents tailor-made for the complexation of uranyl and other actinide ions. These insights, derived from studies of molecular recognition include ion coordination number and geometry, ionic size and ionic shape, as well as ion to ligand thermodynamic affinity. Selectivity for a specific actinide ion will be obtained by providing the polymers with cavities lined with complexing ligands so arranged as to match the charge, coordination number, coordination geometry, and size of the actinide metal ion. These cavity-containing polymers will be produced by using a specific ion (or surrogate) as a template around which monomeric complexing ligands will be polymerized. The complexing ligands will be ones containing functional groups known to form stable complexes with a specific ion and less stable complexes with other cations. Prior investigator's approaches for making templated resins for metal ions have had marginal success. We have extended and amended these methodologies in our work with Pb(II) and uranyl ion, by changing the order of the steps, by the inclusion of sonication, by using higher complex loading, and the selection of functional groups with better complexation constants. This has resulted in significant improvements to selectivity. The unusual shape of the uranyl ion suggests that this approach will result in even greater selectivities than already observed for Pb(II). Preliminary data obtained for uranyl templated polymers shows unprecedented selectivity and has resulted in the first ion selective electrode for uranyl ion.

  7. Release of proteins via ion exchange from albumin-heparin microspheres

    NARCIS (Netherlands)

    Kwon, Glen S.; Bae, You Han; Cremers, Harry; Feijen, Jan; Kim, Sung Wan

    1992-01-01

    Albumin-heparin and albumin microspheres were prepared as ion exchange gels for the controlled release of positively charged polypeptides and proteins. The adsorption isotherms of chicken egg and human lysozyme, as model proteins, on microspheres were obtained. An adsorption isotherm of chicken egg

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

    Energy Technology Data Exchange (ETDEWEB)

    Duffó, G.S. [Departamento de Materiales, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Universidad Nacional de San Martín, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Tecnológicas – CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Farina, S.B., E-mail: farina@cnea.gov.ar [Departamento de Materiales, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Universidad Nacional de San Martín, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Tecnológicas – CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina); Schulz, F.M. [Consejo Nacional de Investigaciones Científicas y Tecnológicas – CONICET, Av. Gral. Paz 1499, 1650 Buenos Aires (Argentina)

    2013-07-15

    Highlights: • There are no works related to the corrosion of drums containing radioactive waste. • Chloride induces high corrosion rate and after 1 year it drops abruptly. • Decrease in the corrosion rate is due to the lack of water to sustain the process. • Cementated ion-exchange resins do not pose risks of corrosion of the steel drums. -- Abstract: Exhausted ion-exchange resins used in nuclear reactors are immobilized by cementation before being stored. They are contained in steel drums that may undergo internal corrosion depending on the presence of certain contaminants. The objective of this work is to evaluate the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different aggressive species. The corrosion potential and the corrosion rate of the steel, and the electrical resistivity of the matrix were monitored for 900 days. Results show that the cementation of ion-exchange resins seems not to pose special risks regarding the corrosion of the steel drums.

  9. The Effects of Sulfonated Poly(ether ether ketone Ion Exchange Preparation Conditions on Membrane Properties

    Directory of Open Access Journals (Sweden)

    Rebecca S. L. Yee

    2013-08-01

    Full Text Available A low cost cation exchange membrane to be used in a specific bioelectrochemical system has been developed using poly(ether ether ketone (PEEK. This material is presented as an alternative to current commercial ion exchange membranes that have been primarily designed for fuel cell applications. To increase the hydrophilicity and ion transport of the PEEK material, charged groups are introduced through sulfonation. The effect of sulfonation and casting conditions on membrane performance has been systematically determined by producing a series of membranes synthesized over an array of reaction and casting conditions. Optimal reaction and casting conditions for producing SPEEK ion exchange membranes with appropriate performance characteristics have been established by this uniquely systematic experimental series. Membrane materials were characterized by ion exchange capacity, water uptake, swelling, potential difference and NMR analysis. Testing this extensive membranes series established that the most appropriate sulfonation conditions were 60 °C for 6 h. For mechanical stability and ease of handling, SPEEK membranes cast from solvent casting concentrations of 15%–25% with a resulting thickness of 30–50 µm were also found to be most suitable from the series of tested casting conditions. Drying conditions did not have any apparent impact on the measured parameters in this study. The conductivity of SPEEK membranes was found to be in the range of 10−3 S cm−1, which is suitable for use as a low cost membrane in the intended bioelectrochemical systems.

  10. Ion-exchanged glass waveguides with low birefringence for a broad range of waveguide widths.

    Science.gov (United States)

    Yliniemi, Sanna; West, Brian R; Honkanen, Seppo

    2005-06-01

    Optical communications networks require integrated photonic components with negligible polarization dependence, which typically means that the waveguides must feature very low birefringence. Recent studies have shown that waveguides with low birefringence can be obtained, e.g., by use of silica-on-silicon waveguides or buried ion-exchanged glass waveguides. However, many integrated photonic circuits consist of waveguides with varying widths. Therefore low birefringence is consequently required for waveguides having different widths. This is a difficult task for most waveguide fabrication technologies. We present experimental results on waveguide birefringence for buried silver-sodium ion-exchanged glass waveguides. We show that the waveguide birefringence of the order of 10(-6) for waveguide mask opening widths ranging from 2 to 10 microm can be obtained by postprocessing the sample through annealing at an elevated temperature. The measured values are in agreement with the values calculated with our modeling software for ion-exchanged glass waveguides. This unique feature of ion-exchanged waveguides may be of significant importance in a wide variety of integrated photonic circuits requiring polarization-independent operation.

  11. Ag clustering investigation in laser irradiated ion-exchanged glasses by optical and vibrational spectroscopy

    Science.gov (United States)

    Trave, E.; Cattaruzza, E.; Gonella, F.; Calvelli, P.; Quaranta, A.; Rahman, A.; Mariotto, G.

    2012-09-01

    Ion exchange process is widely used to dope silicate glass layers with silver for several applications, ranging from light waveguide to nanostructured composite glass fabrication. The silver-doped structure and its physical properties depend on the preparation parameters as well as on subsequent treatments. In particular, laser irradiation of the ion exchanged glasses has been demonstrated to be an effective tool to control cluster size and size distribution. Nevertheless, a complete comprehension of the basic phenomena and a systematic characterization of these systems are still lacking. In this paper, an extended optical characterization is presented for soda-lime glass slides, doped with silver by Ag+-Na+ ion exchange, thermally treated and irradiated with a Nd:YAG laser beam at different wavelengths, and for different energy density. The samples were characterized by various spectroscopic techniques, namely, optical absorption, photoluminescence and micro-Raman analysis. The availability of all these characterization techniques allowed pointing out a suitable scenario for the Ag clustering evolution as a function of the ion exchange, annealing and laser irradiation parameters.

  12. CFD Modeling of Flow and Ion Exchange Kinetics in a Rotating Bed Reactor System

    DEFF Research Database (Denmark)

    Larsson, Hilde Kristina; Schjøtt Andersen, Patrick Alexander; Byström, Emil

    2017-01-01

    be achieved by making the baffles deeper. Two-phase simulations were performed, which managed to reproduce the deflection of the gas–liquid interface in an unbaffled system. A chemical reaction was implemented in the model, describing the ion-exchange phenomena in the porous material using four different...

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

    Science.gov (United States)

    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.

  14. A hydrogen-oxygen fuel cell using an ion-exchange membrane as an electrolyte

    NARCIS (Netherlands)

    Duin, P.J. van; Kruissink, C.A.

    1966-01-01

    Using an acidic type of water leached ion exchange membrane, cell current outputs of the order of 100 mA▪cm-2 at 0,6 V cell voltage have been obtained; the removal of produced water largely limits the cell performance. Cells using the alkaline type of membrane exhibit much smaller current densities,

  15. Charge exchange process with low energy multicharged ions: n, l populations

    Energy Technology Data Exchange (ETDEWEB)

    Chetioui, A.; Rozet, J.P.; Vernhet, D.; Wohrer, K.; Bouisset, P.; Touati, A.; Stephan, C.

    1985-11-01

    Theoretical models for low energy charge exchange collisions of highly charged ions are reviewed in connection with population final states. A simple experimental method is presented which provides the most populated n level, the percentage of p substates and the mean l value. Results are reported for 10 keV/q Al S collisions on H2 and He. (orig.).

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Synthesis of Anomeric Methyl Fructofuranosides and Their Separation on an Ion-Exchange Resin

    Science.gov (United States)

    Nurminen, Erkki; Poijarvi, Paivi; Koskua, Katja; Hovinen, Jari

    2007-01-01

    Treatment of d-fructose with methanol in the presence of acid as a catalyst gives a mixture of methyl-[beta]-d-fructopyranoside, methyl-[alpha]-D-fructofuranoside, and methyl-[beta]-d-fructofuranoside, which were separated on an ion exchange column and characterized polarimetrically.

  18. Controlled transdermal delivery of leuprorelin by pulsed iontophoresis and ion-exchange fiber.

    Science.gov (United States)

    Malinovskaja, Kristina; Laaksonen, Timo; Hirvonen, Jouni

    2014-11-01

    Poor transport efficacy and issues related to biological variation are major concerns in the development of novel iontophoretic devices for the transdermal delivery of therapeutic peptides. The objective of this study was to examine the impact of constant and pulsed current on the transport of nonapeptide leuprorelin acetate across porcine epidermis. Also, the potential of drug delivery system combining iontophoresis and ion-exchange fibers as drug matrices for the delivery of the same peptide was tested. The present study demonstrated the benefit of pulsed current (Tn=2.59×10(-4)) over constant current (Tn=1.7×10(-4)) in terms of more efficient transdermal peptide transport. An increase in the delivery of electroosmotic marker by pulsed current was due to the combined effect of more pronounced electroosmotic transport and reduced inhibition of passive transport. We also showed a promising approach using ion-exchange fibers for controlling the release and iontophoretic transdermal delivery of peptides. Positively charged leuprorelin acetate was bound to the ion-exchange groups of cation-exchange fibers until it was gradually released by mobile counter ions in the external solution. Transdermal flux from acrylic acid grafted Smopex®-102 fibers remained higher (Jss=0.71μg/hcm(2)) than from sulfonic acid grafted Smopex®-101 fibers (Jss=0.31μg/hcm(2)) due to better drug release.

  19. Rate-determining steps in fuel cells with ion exchange membranes

    NARCIS (Netherlands)

    Duin, P.J. van; Kruissink, C.A.

    1967-01-01

    It has been shown by impedance measurements that over a large range of potentials the current at the oxygen electrode of hydrogen-oxygen ion exchange membrane fuel cells is controlled by a charge tra11sfer reaction. The frequency range used covered six decades.

  20. Reactivity of Phenol Allylation Using Phase-Transfer Catalysis in Ion-Exchange Membrane Reactor

    Directory of Open Access Journals (Sweden)

    Ho Shing Wu

    2012-01-01

    Full Text Available This study investigates the reactivity of phenol allylation using quaternary ammonium salt as a phase-transfer catalyst in three types of membrane reactors. Optimum reactivity and turnover of phenol allylation were obtained using a respond surface methodology. The contact angle, water content, and degree of crosslinkage were measured to understand the microenvironment in the ion exchange membrane.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-03-01

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

  3. Separation and characterisation of beta2-microglobulin folding conformers by ion-exchange liquid chromatography and ion-exchange liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Bertoletti, Laura; Regazzoni, Luca; Aldini, Giancarlo; Colombo, Raffaella; Abballe, Franco; Caccialanza, Gabriele; De Lorenzi, Ersilia

    2013-04-10

    In this work we present for the first time the use of ion-exchange liquid chromatography to separate the native form and a partially structured intermediate of the folding of the amyloidogenic protein beta2-microglobulin. Using a strong anion-exchange column that accounts for the differences in charge exposure of the two conformers, a LC-UV method is initially optimised in terms of mobile phase pH, composition and temperature. The preferred mobile phase conditions that afford useful information were found to be 35 mM ammonium formate, pH 7.4 at 25°C. The dynamic equilibrium of the two species is demonstrated upon increasing the concentration of acetonitrile in the protein sample. Then, the chromatographic method is transferred to MS detection and the respective charge state distributions of the separated conformers are identified. The LC-MS results demonstrate that one of the conformers is partially unfolded, compared with the native and more compact species. The correspondence with previous results obtained in free solution by capillary electrophoresis suggest that strong ion exchange LC-MS does not alter beta2-microglobulin conformation and maintains the dynamic equilibrium already observed between the native protein and its folding intermediate.

  4. Effects of Propylene Carbonate Content in CsPF6-Containing Electrolytes on the Enhanced Performances of Graphite Electrode for Lithium-Ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jianming; Yan, Pengfei; Cao, Ruiguo; Xiang, Hongfa; Engelhard, Mark H.; Polzin, Bryant; Wang, Chong M.; Zhang, Jiguang; Xu, Wu

    2016-02-10

    Cesium salt has been demonstrated as an efficient electrolyte additive in suppressing the lithium (Li) dendrite formation and directing the formation of an ultrathin and stable solid electrolyte interphase (SEI) even in propylene carbonate (PC)-ethylene carbonate (EC)-based electrolytes. Here, we further investigate the effect of PC content in the presence of CsPF6 additive (0.05 M) on the performances of graphite electrode in Li||graphite half cells and in graphite||LiNi0.80Co0.15Al0.05O2 (NCA) full cells. It is found that the performance of graphite electrode is also affected by PC content even though CsPF6 additive is present in the electrolytes. An optimal PC content of 20% by weight in the solvent mixtures is identified. The enhanced electrochemical performance of graphite electrode is attributed to the synergistic effects of the Cs+ additive and the PC solvent. The formation of a robust, ultrathin and compact SEI layer containing lithium-enriched species on the graphite electrode, directed by Cs+, effectively suppresses the PC co-intercalation and thus prevents the graphite exfoliation. This SEI layer is only permeable for de-solvated Li+ ions and allows fast Li+ ion transport through it, which therefore largely alleviates the Li dendrite formation on graphite electrode during lithiation even at high current densities. The presence of low-melting-point PC solvent also enables the sustainable operation of the graphite||NCA full cells under a wide spectrum of temperatures. The fundamental findings of this work shed light on the importance of manipulating/maintaining the electrode/electrolyte interphasial stability in a variety of energy storage devices.

  5. Degradation mechanism of sulfonated poly(ether ether ketone) (SPEEK) ion exchange membranes under vanadium flow battery medium.

    Science.gov (United States)

    Yuan, Zhizhang; Li, Xianfeng; Hu, Jinbo; Xu, Wanxing; Cao, Jingyu; Zhang, Huamin

    2014-10-07

    The degradation mechanism of hydrocarbon ion exchange membranes under vanadium flow battery (VFB) medium was investigated and clarified for the first time. This work will be highly beneficial for improving the chemical stability of hydrocarbon ion exchange membranes, which is one of the most challenging issues for VFB application.

  6. Ion exchange substrates for plant cultivation in extraterrestrial stations and space crafts

    Science.gov (United States)

    Soldatov, Vladimir

    2012-07-01

    Ion exchange substrates Biona were specially designed at the Belarus Academy of Sciences for plants cultivation in spacecrafts and extraterrestrial stations. The first versions of such substrates have been successfully used in several space experiments and in a long-term experiment in which three soviet test-spacemen spent a full year in hermetic cabin imitating a lunar station cabin (1067-1968). In this experiment the life support system included a section with about one ton of the ion exchange substrate, which was used to grow ten vegetations of different green cultures used in the food of the test persons. Due to failure of a number of Soviet space experiments, decay of the Soviet Union and the following economic crisis the research in this field carried out in Belarus were re-directed to the needs of usual agriculture, such as adaptation of cell cultures, growing seedlings, rootage of cuttings etc. At present ion exchange substrate Biona are produced in limited amounts at the experimental production plant of the Institute of Physical Organic Chemistry and used in a number of agricultural enterprises. New advanced substrates and technologies for their production have been developed during that time. In the presentation scientific principles of preparation and functioning of ion exchange substrates as well as results of their application for cultivation different plants are described. The ion exchange substrate is a mixture of cation and anion exchangers saturated in a certain proportions with all ions of macro and micro elements. These chemically bound ions are not released to water and become available for plants in exchange to their root metabolites. The substrates contain about 5% mass of nutrient elements far exceeding any other nutrient media for plants. They allow generating 3-5 kg of green biomass per kilogram of substrate without adding any fertilizers; they are sterile by the way of production and can be sterilized by usual methods; allow regeneration

  7. Separation of {sup 134}Cs and {sup 137}Cs from {sup 125}I solution for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Ram, Ramu; Dash, Ashutosh [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Isotope Production and Applications Div.; Banerjee, Dayamoy [Bhabha Atomic Research Centre, Trombay, Mumbai (India). Process Development Div.

    2015-06-01

    While neutron irradiation of natural Xe gas followed by wet chemical dissolution of activation products constitutes a successful paradigm for the small scale production {sup 125}I, the concomitant production of {sup 134}Cs and {sup 137}Cs emerged as the primary impediment which necessitates purification of {sup 125}I solution. This paper describes an ion-exchange chromatographic technique using Resorcinol Formaldehyde (RF) resin to purify {sup 125}I solution from {sup 134}Cs and {sup 137}Cs impurities. A thorough investigation of the adsorption parameters of RF resin was carried out to arrive at the experimental conditions resulting optimum retention of {sup 134}Cs and {sup 137}Cs impurities. Based on the experimental findings, an optimized separation procedure was developed in which the neutron irradiated dissolved products at pH ∝ 13 was passed through a chromatography column containing RF resin where in {sup 134}Cs and {sup 137}Cs impurities gets adsorbed leaving behind {sup 125}I to appear in the effluent. The overall recovery of {sup 125}I was >90% with acceptable purity amenable for clinical applications.

  8. Removal of chromium from electroplating industry effluents by ion exchange resins.

    Science.gov (United States)

    Cavaco, Sofia A; Fernandes, Sandra; Quina, Margarida M; Ferreira, Licínio M

    2007-06-18

    Effluent discharged from the chromium electroplating industry contains a large number of metals, including chromium, copper, nickel, zinc, manganese and lead. The ion exchange process is an alternative technique for application in the treatment of industrial wastewater containing heavy metals and indeed it has proven to be very promising in the removal and recovery of valuable species. The main objective of the present work is to evaluate the performance of commercial ion exchange resins for removing chromium trivalent from industrial effluents, and for this purpose two resins were tested: a chelating exchange resin (Diaion CR11) and a weak cationic resin (Amberlite IRC86). In order to evaluate the sorption capacity of the resins some equilibrium experiments were carried out, being the temperature and pH the main variables considered. The chromium solutions employed in the experiments were synthetic solutions and industrial effluents. In addition, a transient test was also performed as an attempt to understand the kinetic behaviour of the process.

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

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

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

  10. Removal of Carbon Dioxide from Gas Mixtures Using Ion-Exchanged Silicoaluminophosphates

    Science.gov (United States)

    Hernandez-Maldonado, Arturo J (Inventor); Rivera-Ramos, Milton E (Inventor); Arevalo-Hidalgo, Ana G (Inventor)

    2017-01-01

    Na+-SAPO-34 sorbents were ion-exchanged with several individual metal cations for CO2 absorption at different temperatures (273-348 K) and pressures (<1 atm). In general, the overall adsorption performance of the exchanged materials increased as follows: Ce3+exchanged materials excelled at low-pressure ranges, exhibiting very sharp isotherms slopes at all temperatures. The Sr2+ species were responsible for the surface strong interaction and the cations were occupying exposed sites (SII') in the materials Chabazite cages. All the sorbent materials exhibited higher affinity for CO2 over the other gases tested (i.e., CH4, H2, N2 and O2) due to strong ion-quadrupole interactions. Sr2+-SAPO-34 sorbents are by far the best option for CO2 removal from CH4 mixtures, especially at low concentrations.

  11. Encapsulation of Cs/Sr contaminated clinoptilolite in geopolymers produced from metakaolin

    Science.gov (United States)

    Kuenzel, C.; Cisneros, J. F.; Neville, T. P.; Vandeperre, L. J.; Simons, S. J. R.; Bensted, J.; Cheeseman, C. R.

    2015-11-01

    The encapsulation of caesium (Cs) and strontium (Sr) contaminated clinoptilolite in Na and K based metakaolin geopolymers is reported. When Cs or Sr loaded clinoptilolite is mixed with a metakaolin geopolymer paste, the high pH of the activating solution and the high concentration of ions in solution cause ion exchange reactions and dissolution of clinoptilolite with release of Cs and Sr into the geopolymer matrix. The leaching of Cs and Sr from metakaolin-based geopolymer has therefore been investigated. It was found that Na-based geopolymers reduce leaching of Cs compared to K-based geopolymers and the results are in agreement with the hard and soft acids and bases (HSAB) theory. Cs ions are weak Lewis acids and aluminates are a weak Lewis base. During the formation of the geopolymer matrix Cs ions are preferentially bound to aluminate phases and replace Na in the geopolymer structure. Sr uptake by Na-geopolymers is limited to 0.4 mol Sr per mole of Al and any additional Sr is immobilised by the high pH which causes precipitation of Sr as low solubility hydroxide and carbonate phases. There was no evidence of any other phases being formed when Sr or Cs are added to metakaolin geopolymers.

  12. Chaotic behavior of ion exchange phenomena in polymer gel electrolytes through irradiated polymeric membrane

    Energy Technology Data Exchange (ETDEWEB)

    Rawat, Sangeeta; Saha, Barnamala; Prasad, Awadhesh [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Chandra, Amita, E-mail: achandra@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

    2012-05-14

    A desktop experiment has been done to show the nonlinearity in the I–V characteristics of an ion conducting electrochemical micro-system. Its chaotic dynamics is being reported for the first time which has been captured by an electronic circuit. Polyvinylidene fluoride-co-hexafluoropropene (PVdF-HFP) gel electrolyte comprising of a combination of plasticizers (ethylene carbonate and propylene carbonate) and salts have been prepared to study the exchange of ions through porous polyethylene terephthalate (PET) membranes. The nonlinearity of this system is due to the ion exchange of the polymer gel electrolytes (PGEs) through a porous membrane. The different regimes of spiking and non-spiking chaotic motions are being presented. The possible applications are highlighted. -- Highlights: ► For the first time, the nonlinear dynamics of an electrochemical micro-system has been reported. ► The nonlinearity generates due to the ion exchange of polymer gel electrolytes through irradiated polymeric membrane. ► The nonlinearity can be tailored by changing the pore size of irradiated membrane. ► Sprott's circuit has been modified to capture the phenomena of ion transport through membrane. ► Attractor formation and Lyapunov exponent confirms the chaotic behavior of presently investigated system.

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

    Science.gov (United States)

    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.

  14. Alkaline aluminum phosphate glasses for thermal ion-exchanged optical waveguide

    Science.gov (United States)

    Wang, Fei; Chen, Baojie; Pun, Edwin Yue Bun; Lin, Hai

    2015-04-01

    Alkaline aluminum phosphate glasses (NMAP) with excellent chemical durability for thermal ion-exchanged optical waveguide have been designed and investigated. The transition temperature Tg (470 °C) is higher than the ion-exchange temperature (390 °C), which is favorable to sustain the stability of the glass structure for planar waveguide fabrication. The effective diffusion coefficient De of K+-Na+ ion exchange in NMAP glasses is 0.110 μm2/min, indicating that ion exchange can be achieved efficiently in the optical glasses. Single-mode channel waveguide has been fabricated on Er3+/Yb3+ doped NMAP glass substrate by standard micro-fabrication and K+-Na+ ion exchange. The mode field diameter is 9.6 μm in the horizontal direction and 6.0 μm in the vertical direction, respectively, indicating an excellent overlap with a standard single-mode fiber. Judd-Ofelt intensity parameter Ω2 is 5.47 × 10-20 cm2, implying a strong asymmetrical and covalent environment around Er3+ in the optical glasses. The full width at half maximum and maximum stimulated emission cross section of the 4I13/2 → 4I15/2 are 30 nm and 6.80 × 10-21 cm2, respectively, demonstrating that the phosphate glasses are potential glass candidates in developing compact optoelectronic devices. Pr3+, Tm3+ and Ho3+ doped NMAP glasses are promising candidates to fabricate waveguide amplifiers and lasers operating at special telecommunication windows.

  15. Transport, charge exchange and loss of energetic heavy ions in the earth's radiation belts - Applicability and limitations of theory

    Science.gov (United States)

    Spjeldvik, W. N.

    1981-01-01

    Computer simulations of processes which control the relative abundances of ions in the trapping regions of geospace are compared with observations from discriminating ion detectors. Energy losses due to Coulomb collisions between ions and exospheric neutrals are considered, along with charge exchange losses and internal charge exchanges. The time evolution of energetic ion fluxes of equatorially mirroring ions under radial diffusion is modelled to include geomagnetic and geoelectric fluctutations. Limits to the validity of diffusion transport theory are discussed, and the simulation is noted to contain provisions for six ionic charge states and the source effect on the radiation belt oxygen ion distributions. Comparisons are made with ion flux data gathered on Explorer 45 and ISEE-1 spacecraft and results indicate that internal charge exchanges cause the radiation belt ion charge state to be independent of source charge rate characteristics, and relative charge state distribution is independent of the radially diffusive transport rate below the charge state redistribution zone.

  16. Comparison of ion exchange and cw CO2 laser treatment of Nd-doped phosphate laser glass

    Science.gov (United States)

    Hui, Gong; Chengfu, Li

    1996-05-01

    In recent years, the effect of laser pre-irradiation and ion exchange on glasses surface were widely carried out to stabilize their damage thresholds. But comparison of ion exchange and CW CO2 laser treatment is never studied, this paper is devoted to the investigation of this question. Nd-doped phosphate laser glasses were heated with CW CO2 laser radiation and were strengthened by ion exchange. Laser damage thresholds of the surface were measured with 1064 nm 10 ns pulses focused to small spots irradiation. Both ion exchange treatment and CW CO2 laser treatment result in residual compress stress occurred at surface, peak-to- volley and microcracks decreased in surface appearance, and damage thresholds of surfaces increased by a factor of over 2. Polariscope, reflected optical microscope and atomic force microscope are used for stress, damage morphologies and surface topography analysis on glass surface. It is shown that laser condition mechanism is consistent with ion exchange treatment mechanism.

  17. Ion Exchange Equilibrium and Kinetic Properties of Polyacrylate Films and Applications to Chemical Analysis and Environmental Decontamination

    Science.gov (United States)

    Tanner, Stephen P.

    1997-01-01

    One of the goals of the original proposal was to study how cross-linking affects the properties of an ion exchange material(IEM) developed at Lewis Research Center. However, prior to the start of this work, other workers at LERC investigated the effect of cross-linking on the properties of this material. Other than variation in the ion exchange capacity, the chemical characteristics were shown to be independent of the cross-linking agent, and the degree of cross-linking. New physical forms of the film were developed (film, supported film, various sizes of beads, and powder). All showed similar properties with respect to ion exchange equilibria but the kinetics of ion exchange depended on the surface area per unit mass; the powder form of the IEM exchanging much more rapidly than the other forms. The research performed under this grant was directed towards the application of the IEM to the analysis of metal ions at environmental concentrations.

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

    Science.gov (United States)

    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.

  19. Indirect UV detection-ion-exclusion/cation-exchange chromatography of common inorganic ions with sulfosalicylic acid eluent.

    Science.gov (United States)

    Kozaki, Daisuke; Mori, Masanobu; Nakatani, Nobutake; Arai, Kaori; Masuno, Tomoe; Koseki, Masakazu; Itabashi, Hideyuki; Tanaka, Kazuhiko

    2013-01-01

    Herein, we describe indirect UV detection-ion-exclusion/cation-exchange chromatography (IEC/CEC) on a weakly acidic cation-exchange resin in the H(+)-form (TSKgel Super IC-A/C) using sulfosalicylic acid as the eluent. The goal of the study was to characterize the peaks detected by UV detector. The peak directions of analyte ions in UV at 315 nm were negative because the molar absorbance coefficients of analyte anions and cations were lower than that of the sulfosalicylic acid eluent. Good chromatographic resolution and high signal-to-noise ratios of analyte ions were obtained for the separations performed using 1.1 mM sulfosalicylic acid and 1.5 mM 18-crown-6 as the eluent. The relative standard deviations (RSDs) of the peak areas ranged from 0.6 to 4.9%. Lower detection limits of the analytes were achieved using indirect UV detection at 315 nm (0.23 - 0.98 μM) than those obtained with conductometric detection (CD) (0.61 - 2.1 μM) under the optimized elution conditions. The calibration curves were linear in the range from 0.01 to 1.0 mM except for Cl(-), which was from 0.02 to 2.0 mM. The present method was successfully applied to determine common inorganic ions in a pond water sample.

  20. Removal of charged micropollutants from water by ion-exchange polymers -- effects of competing electrolytes.

    Science.gov (United States)

    Bäuerlein, Patrick S; Ter Laak, Thomas L; Hofman-Caris, Roberta C H M; de Voogt, Pim; Droge, Steven T J

    2012-10-15

    A wide variety of environmental compounds of concern, e.g. pharmaceuticals or illicit drugs, are acids or bases that may predominantly be present as charged species in drinking water sources. These charged micropollutants may prove difficult to remove by currently used water treatment steps (e.g. UV/H(2)O(2), activated carbon (AC) or membranes). We studied the sorption affinity of some ionic organic compounds to both AC and different charged polymeric materials. Ion-exchange polymers may be effective as additional extraction phases in water treatment, because sorption of all charged compounds to oppositely charged polymers was stronger than to AC, especially for the double-charged cation metformin. Tested below 1% of the polymer ion-exchange capacity, the sorption affinity of charged micropollutants is nonlinear and depends on the composition of the aqueous medium. Whereas oppositely charged electrolytes do not impact sorption of organic ions, equally charged electrolytes do influence sorption indicating ion-exchange (IE) to be the main sorption mechanism. For the tested polymers, a tenfold increased salt concentration lowered the IE-sorption affinity by a factor two. Different electrolytes affect IE with organic ions in a similar way as inorganic ions on IE-resins, and no clear differences in this trend were observed between the sulphonated and the carboxylated cation-exchanger. Sorption of organic cations is five fold less in Ca(2+) solutions compared to similar concentrations of Na(+), while that of anionic compounds is three fold weaker in SO(4)(2-) solutions compared to equal concentrations of Cl(-).

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

    Science.gov (United States)

    El-Kamash, A M

    2008-03-01

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

  2. Taste masking of ciprofloxacin by ion-exchange resin and sustain release at gastric-intestinal through interpenetrating polymer network

    Directory of Open Access Journals (Sweden)

    A. Michael Rajesh

    2015-07-01

    Full Text Available The aim of the study was to taste mask ciprofloxacin (CP by using ion-exchange resins (IERs followed by sustain release of CP by forming interpenetrating polymer network (IPN. IERs based on the copolymerization of acrylic acid with different cross linking agents were synthesised. Drug-resin complexes (DRCs with three different ratios of drug to IERs (1:1, 1:2, 1:4 were prepared & evaluated for taste masking by following in vivo and in vitro methods. Human volunteers graded ADC 1:4, acrylic acid-divinyl benzene (ADC-3 resin as tasteless. Characterization studies such as FTIR, SEM, DSC, P-XRD differentiated ADC 1:4, from physical mixture (PM 1:4 and confirmed the formation of complex. In vitro drug release of ADC 1:4 showed complete release of CP within 60 min at simulated gastric fluid (SGF i.e. pH 1.2. IPN beads were prepared with ADC 1:4 by using sodium alginate (AL and sodium alginate-chitosan (AL-CS for sustain release of CP at SGF pH and followed by simulated intestinal fluid (SIF i.e. pH 7.4. FTIR spectra confirmed the formation of IPN beads. The release of CP was sustain at SGF pH (75%. The kinetic model of IPN beads showed the release of CP was non-Fickian diffusion type.

  3. Synthesis and exchange properties of sulfonated poly(phenylene sulfide) with alkali metal ions in organic solvents

    Energy Technology Data Exchange (ETDEWEB)

    Son, Won Keun [Chungnam National Univ., Taejon (Korea, Republic of); Kim, Sang Hern [Taejon National Univ., Taejon (Korea, Republic of); Park, Soo Gil [Chungbuk National Univ., Cheongju (Korea, Republic of)

    2001-01-01

    Sulfonated poly(phenylene sulfide) (SPPS) polymers were prepared by sulfonation of poly[methyl[4-(phenylthio)phenyl] sulfonium trifluoromethanesulfonate] (PPST) with fumic sulfonic acid (10% SO{sub 3}-H{sub 2}SO{sub 4}) and demethylation with aqueous NaOH solution. The equilibrium constants of ion exchange reactions between alkali metal cations (Li{sup +}, Na{sup +}, and K{sup +}) and SPPS ion exchanger in organic solvents such as in organic solvents such as tetrahydrofuran (THF) and dioxane were measured. The equilibrium constants of ion exchange reactions increased as the polarity of the solvent increased, and the reaction temperature decreased. The equilibrium constants of the ion exchange reaction (K{sub eq}) also increased in the order of Li{sup +}, Na{sup +}, and K{sup +}. To elucidate the spontaneity of the exchange reaction in organic solvents, the enthalpy, entropy, and Gibbs free energy were calculated. The enthalpy of reaction ranged from -0.88 to -1.33 kcal/mol, entropy ranged from 1.42 to 4.41 cal/Kmol, and Gibbs free energy ranged from -1.03 to -2.55 kcal/mol. Therefore, the exchange reactions were spontaneous because the Gibbs free energies were negative. The SPPS ion exchanger and alkali metal ion bounding each other produced good ion exchange capability in organic solvents.

  4. The Ring Counter (RCo): A high resolution IC-Si-CsI(Tl) device for heavy ion reaction studies at 10-30 MeV/A

    Energy Technology Data Exchange (ETDEWEB)

    Moroni, A.; Brambilla, S.; Giussani, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Milano and Dipartimento di Fisica dell' Universita, Milan (Italy); Bruno, M. [Istituto Nazionale di Fisica Nucleare, Sezionedi Bologna and Dipartimento di Fisica dell' Universita, Bologna (Italy); Bardelli, L. [Istituto Nazionale di Fisica Nucleare, Sezione di Firenze and Dipartimento di Fisica dell' Universita, Florence (Italy); Barlini, S. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (Italy); Casini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Firenze and Dipartimento di Fisica dell' Universita, Florence (Italy); Cavaletti, R. [Istituto Nazionale di Fisica Nucleare, Sezionedi Bologna and Dipartimento di Fisica dell' Universita, Bologna (Italy); Chiari, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Firenze and Dipartimento di Fisica dell' Universita, Florence (Italy); Cortesi, A. [Istituto Nazionale di Fisica Nucleare, Sezione di Milano and Dipartimento di Fisica dell' Universita, Milan (Italy); D' Agostino, M. [Istituto Nazionale di Fisica Nucleare, Sezionedi Bologna and Dipartimento di Fisica dell' Universita, Bologna (Italy)]. E-mail: dagostino@bo.infn.it; De Sanctis, J. [Istituto Nazionale di Fisica Nucleare, Sezionedi Bologna and Dipartimento di Fisica dell' Universita, Bologna (Italy); Geraci, E. [Istituto Nazionale di Fisica Nucleare, Sezionedi Bologna and Dipartimento di Fisica dell' Universita, Bologna (Italy); Giordano, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Napoli and Dipartimento di Fisica dell' Universita, Napoli (Italy); Gramegna, F. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (Italy); Guiot, B. [Istituto Nazionale di Fisica Nucleare, Sezionedi Bologna and Dipartimento di Fisica dell' Universita, Bologna (Italy); Kravchuk, V.; Lanchais, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro (Italy)] [and others

    2006-01-15

    An annular detector (Ring Counter, RCo) is presented, which has been designed and built to detect and identify in mass and charge light charged particles and fragments with very low energy thresholds and high energy resolution. It complements the GARFIELD apparatus, operating at INFN Laboratori Nazionali di Legnaro, to detect the forward emitted products of nuclear heavy ion reactions. It consists of eight sectors of a three-stage telescope, each one formed by an ionization chamber followed by eight strips of a silicon detector and by two CsI(Tl) scintillators. Construction features and performances are described and discussed in details.

  5. The Ring Counter (RCo): A high resolution IC Si CsI(Tl) device for heavy ion reaction studies at 10 30 MeV/A

    Science.gov (United States)

    Moroni, A.; Bruno, M.; Bardelli, L.; Barlini, S.; Brambilla, S.; Casini, G.; Cavaletti, R.; Chiari, M.; Cortesi, A.; D'Agostino, M.; De Sanctis, J.; Geraci, E.; Giordano, G.; Giussani, A.; Gramegna, F.; Guiot, B.; Kravchuk, V.; Lanchais, A.; Margagliotti, G. V.; Nannini, A.; Ordine, A.; Piantelli, S.; Vannini, G.; Vannucci, L.

    2006-01-01

    An annular detector (Ring Counter, RCo) is presented, which has been designed and built to detect and identify in mass and charge light charged particles and fragments with very low energy thresholds and high energy resolution. It complements the GARFIELD apparatus, operating at INFN Laboratori Nazionali di Legnaro, to detect the forward emitted products of nuclear heavy ion reactions. It consists of eight sectors of a three-stage telescope, each one formed by an ionization chamber followed by eight strips of a silicon detector and by two CsI(Tl) scintillators. Construction features and performances are described and discussed in details.

  6. Determination of the maximum retention of cobalt by ion exchange in h-zeolites

    Directory of Open Access Journals (Sweden)

    A. S. Zola

    2012-06-01

    Full Text Available This work aimed to determine the maximum content of cobalt that can be incorporated by ion exchange in zeolites H-USY, H-Beta, H-Mordenite, and H-ZSM-5. To reach this goal, batch isotherms at 75ºC were constructed after addition of zeolite samples in flasks filled with cobalt nitrate solution. The equilibrium data were fitted to Langmuir, Freundlich, and Tóth adsorption isotherm models. Langmuir was the best model for zeolites H-Beta, H-Mordenite, and H-ZSM-5, whereas experimental data for H-USY were better fitted to the Freundlich isotherm model. From the isotherms, it was possible to determine the maximum cobalt exchange level (q max that can be incorporated in each zeolite through ion exchange. In this sense, H-USY presented the highest q max value (2.40 meq/g zeol, while H-ZSM-5 showed the lowest one (0.64 meq/g zeol. These results also show the influence of the zeolite framework related to the channel system, pore opening, presence of cavities and secondary porosity and SiO2/Al2O3 ratio (SAR on the maximum capacity and behavior of cobalt ion exchange in protonic zeolites.

  7. Preparation of Ion Exchange Films for Solid-Phase Spectrophotometry and Solid-Phase Fluorometry

    Science.gov (United States)

    Hill, Carol M.; Street, Kenneth W.; Tanner, Stephen P.; Philipp, Warren H.

    2000-01-01

    Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this report we present a method for making ion exchange polymer films, which considerably simplify the solid-phase spectroscopic techniques. The polymer consists of formaldehyde-crosslinked polyvinyl alcohol with polyacrylic acid entrapped therein. The films are a carboxylate weak cation exchanger in the calcium form. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.

  8. Overloading ion-exchange membranes as a purification step for monoclonal antibodies.

    Science.gov (United States)

    Brown, Arick; Bill, Jerome; Tully, Timothy; Radhamohan, Asha; Dowd, Chris

    2010-06-11

    The present study examined the overloading of ion-exchange membrane adsorbers, a form of frontal chromatography, as the final purification step in the production of mAbs (monoclonal antibodies) produced from CHO (Chinese-hamster ovary) cells. Preferential binding of impurities over antibody product was exploited using commercially available cation- and anion-exchange membranes. Three different antibody feedstreams previously purified over Protein A and ion-exchange column chromatography were tested. Feedstream conductivity and pH were adjusted to induce product and impurity adsorption. Membranes were then overloaded in a normal flow mode, resulting in retention of impurities and breakthrough of purified antibody. Although some amount of the product also binds to the membranes (usually or =99% were achieved by marginalizing the losses, typically by loading more than 3 kg mAb/l membrane. Analyses of the purified pools show consistent removal of impurities despite strong mAb-ligand interactions and high membrane loadings. The clearance of host cell proteins was affected by pH and conductivity, but was unaffected by flow rate, membrane properties or scale. The importance of the present study lies in our demonstration of an alternative use of ion-exchange membranes for fast, effective and high yielding purification of mAbs.

  9. Ag clustering investigation in laser irradiated ion-exchanged glasses by optical and vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Trave, E., E-mail: enrico.trave@unive.it [Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venezia, Dorsoduro 2137, I-30123 Venezia (Italy); Cattaruzza, E.; Gonella, F.; Calvelli, P. [Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venezia, Dorsoduro 2137, I-30123 Venezia (Italy); Quaranta, A. [Department of Materials Engineering and Industrial Technologies, University of Trento, via Mesiano 77, I-38050 Povo (Italy); Rahman, A.; Mariotto, G. [Department of Computer Science, University of Verona, Strada le Grazie 15, 37134 Verona (Italy)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer We modify the properties of Ag{sup +} exchanged glasses by thermal and laser treatment. Black-Right-Pointing-Pointer The induced microstructural changes are analyzed by optical and Raman spectroscopy. Black-Right-Pointing-Pointer Ag-based species in the glass show a peculiar PL activity in the UV-Vis range. Black-Right-Pointing-Pointer Raman and OA analysis allow for determining the Ag cluster size evolution. Black-Right-Pointing-Pointer Laser processing leads to different cluster formation and fragmentation mechanisms. - Abstract: Ion exchange process is widely used to dope silicate glass layers with silver for several applications, ranging from light waveguide to nanostructured composite glass fabrication. The silver-doped structure and its physical properties depend on the preparation parameters as well as on subsequent treatments. In particular, laser irradiation of the ion exchanged glasses has been demonstrated to be an effective tool to control cluster size and size distribution. Nevertheless, a complete comprehension of the basic phenomena and a systematic characterization of these systems are still lacking. In this paper, an extended optical characterization is presented for soda-lime glass slides, doped with silver by Ag{sup +}-Na{sup +} ion exchange, thermally treated and irradiated with a Nd:YAG laser beam at different wavelengths, and for different energy density. The samples were characterized by various spectroscopic techniques, namely, optical absorption, photoluminescence and micro-Raman analysis. The availability of all these characterization techniques allowed pointing out a suitable scenario for the Ag clustering evolution as a function of the ion exchange, annealing and laser irradiation parameters.

  10. Environmentally benign hardness removal using ion-exchange fibers and snowmelt.

    Science.gov (United States)

    Greenleaf, John E; Sengupta, Arup K

    2006-01-01

    Many industrial unit operations and unit processes require near-complete removal of hardness to avoid scaling in heat-transfer equipment, fouling in membranes, and high consumption of detergents and sequestering chemicals in cooling and wash water. Lime softening and cation exchange are the most commonly used processes practiced to date for hardness removal. Herein, we report and discuss the results and attributes of a new hardness removal process using ion-exchange fibers (IX-fibers). Most importantly, the process uses harvested snowmelt (or rainwater) as the regenerant chemical along with sparged carbon dioxide. Consequently, the spent regenerant does not contain a high concentration of aggressive chemicals such as sodium chloride or acid like traditional ion-exchange processes nor does the process produce voluminous sludges similar to lime softening. The bulk of carbon dioxide consumed during regeneration remains sequestered in the aqueous phase as alkalinity. IX-fibers form the heart of the process. They are essentially thin cylindrical polymeric strands 10-20 microm in diameter. The weak-acid carboxylate functional groups reside near to the surface of these cylindrical fibers. Low intraparticle diffusional resistance is the underlying reason IX-fibers are amenable to efficient regeneration with snowmelt sparged with carbon dioxide. When the carbon dioxide partial pressure is increased to 6.8 atm, over 90% calcium desorption efficiency is obtained. On the contrary, commercial weak-acid ion-exchange resins in spherical bead forms are ineffective for regeneration with carbon-dioxide-sparged snowmelt due to extremely slow ion-exchange kinetics involving counter-transport of Ca2+ and H+.

  11. Characterization of cross-linked cellulosic ion-exchange adsorbents: 2. Protein sorption and transport.

    Science.gov (United States)

    Angelo, James M; Cvetkovic, Aleksandar; Gantier, Rene; Lenhoff, Abraham M

    2016-03-18

    Adsorption behavior in the HyperCel family of cellulosic ion-exchange materials (Pall Corporation) was characterized using methods to assess, quantitatively and qualitatively, the dynamics of protein uptake as well as static adsorption as a function of ionic strength and protein concentration using several model proteins. The three exchangers studied all presented relatively high adsorptive capacities under low ionic strength conditions, comparable to commercially available resins containing polymer functionalization aimed at increasing that particular characteristic. The strong cation- and anion-exchange moieties showed higher sensitivity to increasing salt concentrations, but protein affinity on the salt-tolerant STAR AX HyperCel exchanger remained strong at ionic strengths normally used in downstream processing to elute material fully during ion-exchange chromatography. Very high uptake rates were observed in both batch kinetics experiments and time-series confocal laser scanning microscopy, suggesting low intraparticle transport resistances relative to external film resistance, even at higher bulk protein concentrations where the opposite is typically observed. Electron microscopy imaging of protein adsorbed phases provided additional insight into particle structure that could not be resolved in previous work on the bare resins.

  12. Comparison of the ion exchange uptake of ammonium ion onto New Zealand clinoptilolite and mordenite.

    Science.gov (United States)

    Weatherley, L R; Miladinovic, N D

    2004-12-01

    In this study the uptake performances of the naturally occurring zeolite, clinoptilolite, and of New Zealand mordenite are compared. The uptake of fully ionised ammonium ion from aqueous solutions in the concentration range 0-200 mg/l on to these two materials was compared. The influence of other cations present in water upon the ammonia uptake was also determined. The cations studied were potassium, calcium and magnesium. In all cases the anionic counterion present was chloride. The results showed that the mordenite exhibited higher overall uptake concentrations at equilibrium compared with clinoptilolite at solution concentrations greater than 80 mg/l. Beyond this value, the difference in solid-phase equilibrium concentrations on the mordenite became greater at higher solution-phase ammonium ion concentrations. The effect of the other cations upon uptake of ammonium ion was relatively small. In all cases, the ammonium ion showed the highest uptake on to both the mordenite and the clinoptilolite. In the case of clinoptilolite this was rather an unexpected result since the majority of other work shows clinoptilolite exhibiting a higher affinity for potassium ion compared with ammonium ion. This may be explained by the fact that the clinoptilolite came from volcanic deposits in New Zealand. This is the first such study on this material. At solution-phase equilibrium concentrations of greater than 80 mg/l, the mordenite showed smaller reductions in ammonium ion uptake in the presence of the other cations when compared with clinoptilolite.

  13. Potentiometric Multisensory Systems with Novel Ion-Exchange Polymer-Based Sensors for Analysis of Drugs

    Directory of Open Access Journals (Sweden)

    Olga V. Bobreshova

    2012-01-01

    Full Text Available This paper examines potentiometric multisensory systems that consist of novel cross-sensitive PD-sensors (Potential Donnan-sensors. The analytical signal of PD-sensors is the Donnan potential at the ion-exchange polymer/electrolyte test solution interface. The use of novel sensors for the quantitative analysis of multicomponent aqueous solutions of amino acids, vitamins and medical substances is based on protolytic and ion-exchange reactions at the interfaces of ion-exchangers and test solutions. The potentiometric sensor arrays consist of PD-sensors and ion-selective electrodes. Such systems were developed for the multicomponent quantitative analysis of lysine monohydrochloride, thiamine chloride and novocaine hydrochloride solutions that contained salts of alkaline and alkaline-earth metals, as well as for mixed solutions of nicotinic acid and pyridoxine hydrochloride. Multivariate methods of analysis were used for sensor calibration and the analysis of the total response of sensor arrays. The errors of measurement of the electrolytes in aqueous solutions did not exceed 10%. The developed multisensory systems were used to determine the composition of a therapeutic “Mineral salt with low content of sodium chloride” and to determine concentrations of novocaine in sewage samples from a dental clinic.

  14. Adsorption of gaseous formaldehyde and carboxylic acids by ammonium-ion-exchanged alpha-zirconium phosphate.

    Science.gov (United States)

    Hayashi, A; Fujimoto, Y; Ogawa, Y; Nakayama, H; Tsuhako, M

    2005-03-01

    Ammonium-ion-exchanged alpha-Zr(HPO(4))(2)H(2)O (alpha-ZrP) was obtained as a single phase with the interlayer distance of 9.4 A by the ion-exchange of proton with ammonium ion. The ammonium ion-exchanged alpha-ZrP could adsorb ill-smelling gases, such as formaldehyde and carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid). The adsorption amounts of carboxylic acids increased in the order, butyric acid

  15. 掺杂 Nd3+离子 CsCdBr3晶体光谱的理论分析%Theoretical Analysis of Spectra for Nd3 + Ions in CsCdBr 3 Crystals

    Institute of Scientific and Technical Information of China (English)

    苏萍; 李邦兴

    2015-01-01

    运用稀土自由离子理论和晶体场理论,通过对掺杂 Nd3+离子的 CsCdBr3晶体的发光光谱的计算分析,分别拟合了实验光谱数据中的28、47和65条能级,得出理论晶场能级与实验值的标准差分别为3.83,12.367和25.852 cm -1。该结果比已有的拟合结果小得多,表明此计算结果与实验光谱吻合得较好,说明拟合过程和方法是合理的。同时得到了合理的自由离子参量和晶场参量,为进一步研究稀土离子在晶体材料中受到晶体场作用的各种物理机制打下基础。%The optical spectra of Nd3 + in CsCdBr3 were calculated by using the free rare earth ion the-ory and crystal field theory. Respectively,28,47,65 experimental crystal field levels were fitted, with the standard deviations of 3. 83 cm - 1 ,12. 367 cm - 1 ,25. 852 cm - 1 . These deviations are signif-icantly smaller than those in previous work. The calculated energy levels fit better with the experimen-tal data,which shows that the calculation process and the method are reasonable. Through this fitting procedure,the reasonable free-ion and crystal-field parameters have been obtained. It is beneficial for further research on the physical mechanisms of crystal field of rare earth ions in crystals.

  16. 纳米晶复合Er3+掺杂Ge-In-S-CsI玻璃的发光性能%Luminescence Properties of Nanocrystals Composited Er3+Ions Doped Ge-In-S-CsI Glasses

    Institute of Scientific and Technical Information of China (English)

    戚嘉妮; 许银生; 魏淑林; 陈飞飞; 林常规; 徐铁峰; 戴世勋

    2013-01-01

      纳米晶复合的玻璃材料在稀土离子发光方面有着重要的研究意义。用真空熔融淬冷法制备了Er3+掺杂的70GeS2–20In2S3–10CsI玻璃样品,研究了不同温度和时间热处理玻璃基质内部析出的纳米晶对Er3+发光性能的影响。结果表明:随着热处理温度和时间的增加,玻璃样品的短波截止波长发生了明显的红移现象。在380℃经过18 h热处理后的玻璃样品析出均匀的纳米晶颗粒,尺寸约为10~20 nm。玻璃基质中先后析出In2S3和GeS2晶体。玻璃样品在380℃,经过12 h热处理后,Er3+在1540 nm处的发光增强了3倍,有望应用于C波段通讯用光纤放大器。%The Er2S3 and Ag2S co-doped 70GeS2-20In2S3-10CsI glasses were synthesized by a vacuumed melt-quenching technique. The influence of precipitated nanocrystal on the luminescence properties of RE (rare earth) ions was investigated. The short-wavelength absorption edge appears red-shift when the temperature and duration increase. For the samples treated at 380 for 12℃ h, the nanocrystals in the size range from 10 to 20 nm disperse homogeneously in the glass. The In2S3 and GeS2 nanocrystals precipitate successively. The intensity of 1 540 nm luminescence of Er3+ions is three times greater than that of the glass matrix. The Er3+ions doped chalcogenide glasses with the nanocrystals have potential applications in the C band optical fiber amplifier.

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

    Science.gov (United States)

    Dominguez, Lourdes

    Ion exchange materials coated on glass fiber substrates have a number of advantages over the conventional ion exchange beads. These include simplification of the overall synthesis including faster more efficient functionalization and elimination of toxic solvents. Other benefits include the ability to be fabricated in the form of felts, papers, or fabrics, improving media contact efficiency and enhancing both the rates of reaction and regeneration. In addition, physical and mechanical requirements of strength and dimensional stability are achieved by use of glass fiber substrates. Investigations were focused on design of: (1) polymeric cationic exchange fibers and their application for lead and mercury removal, (2) polymeric anionic exchange fibers and their application for arsenate removal, (3) enhancement of anionic fiber selectivity for monovalent ions over divalent ions through bulkier triaklylamine functional groups, and (4) polymeric mercaptyl fibers for the application of arsenite removal. The design and characterization of a cationic exchange fiber is described. Dynamic mode (breakthrough) experiments for calcium, lead, and mercury ion solutions are also presented. The second system consists of the preparation and characterization of anionic exchange fibers with equilibrium adsorption isotherms and dynamic mode kinetic experiments for arsenate removal. Modification of the resin with bulkier functional groups (trimethylamine, triethylamine, tripropylamine, tributylanmine), thereby effecting a change in the selectivity from divalent species to monovalent species, is considered in the separation of nitrates from sulfates. The ability of a thiol group to bind to the highly toxic arsenite ion (as is done in proteins and enzymes) provided the model used to chemically modify and characterize a polyvinyl alcohol mercaptyl fibrous system, coated on a fiberglass substrate, for the purpose of arsenite (As3+) removal from water. Physical/chemical aspects of naturally

  18. Study of the retention of radionuclides by ion-exchange resins contained in the circuits of a Pressurized Water Reactor; Etude de la retention des radionucleides dans les resines echangeuses d'ions des circuits d'une centrale nucleaire a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Gressier, F.

    2008-11-15

    Physico-chemical quality of fluids in nuclear power plant circuits must be maintained in order to limit contamination and dose rate especially when the shutdown takes place. Nevertheless, an optimum between diminishing liquid waste and limiting solid waste production has to be reached, but at affordable costs. Ion-exchange resins of purification circuits are used to fulfill this goal. In this work, different resin types have been characterized (exchange capacity, water and electrolyte sorption) and their selectivity towards Co{sup 2+}, Ni{sup 2+}, Cs{sup +} and Li{sup +} cations have been studied. We have shown that the two cation-exchange resins selectivity varies according to the nature and concentrations of their counter-ions. Moreover, flow rate (and thus hydro-kinetics) impact on species retention in a column has been characterized: the more the flow rate, the more the ionic leakage (output concentration divided by input concentration) is fast and the more the output concentration front is spread. A literature revue has enabled to put in light advantages and drawbacks of the models of interest to simulate operations of ion-exchange resins. Thus, the pure end-members mixing model associated to a non-ideality description of the resin phase based on the regular solutions model has been retained for modelling ion-exchange equilibrium. Ion-exchange kinetics has been described by mass transfer coefficients. Using the experimental results to determine model parameters, these last ones have been implemented in a speciation code CHESS, coupled with a hydrodynamic code in HYTEC. On the one hand, equilibrium experiments of ion retention have been simulated and, on the other hand, column retention tests have been modelled. Finally, selectivity variations and hydro-kinetics impacts have been simulated on some test cases so as to demonstrate the importance of taking these into account when simulating ion-exchange resins operations. (author)

  19. Charge exchange between two nearest neighbour ions immersed in a dense plasma

    Science.gov (United States)

    Sauvan, P.; Angelo, P.; Derfoul, H.; Leboucher-Dalimier, E.; Devdariani, A.; Calisti, A.; Talin, B.

    1999-04-01

    In dense plasmas the quasimolecular model is relevant to describe the radiative properties: two nearest neighbor ions remain close to each other during a time scale of the order of the emission time. Within the frame of a quasistatic approach it has been shown that hydrogen-like spectral line shapes can exhibit satellite-like features. In this work we present the effect on the line shapes of the dynamical collision between the two ions exchanging transiently their bound electron. This model is suitable for the description of the core, the wings and the red satellite-like features. It is post-processed to the self consistent code (IDEFIX) giving the adiabatic transition energies and the oscillator strengths for the transient molecule immersed in a dense free electron bath. It is shown that the positions of the satellites are insensitive to the dynamics of the ion-ion collision. Results for fluorine Lyβ are presented.

  20. Charge-exchange recombination spectroscopy of the plasma ion temperature at the T-10 tokamak

    Science.gov (United States)

    Krupin, V. A.; Tugarinov, S. N.; Barsukov, A. G.; Dnestrovskij, A. Yu.; Klyuchnikov, L. A.; Korobov, K. V.; Krasnyanskii, S. A.; Naumenko, N. N.; Nemets, A. R.; Sushkov, A. V.; Tilinin, G. N.

    2013-08-01

    Charge-exchange recombination spectroscopy (CXRS) based on a diagnostic neutral beam has been developed at the T-10 tokamak. The diagnostics allows one to measure the ion temperature profile in the cross section of the plasma column. In T-10 experiments, the measurement technique was adjusted and the elements of the CXRS diagnostics for ITER were tested. The used spectroscopic equipment makes it possible to reliably determine the ion temperature from the Doppler broadening of impurity lines (helium, carbon), as well as of the spectral lines of the working gas. The profiles of the plasma ion temperature in deuterium and helium discharges were measured at different plasma currents and densities, including with the use of active Doppler measurements of lines of different elements. The validity and reliability of ion temperature measurements performed by means of the developed CXRS diagnostics are analyzed.

  1. Ultra-low vanadium ion diffusion amphoteric ion-exchange membranes for all-vanadium redox flow batteries

    Science.gov (United States)

    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.

  2. Ion exchange equilibrium for some uni-univalent and uni-divalent reaction systems using strongly basic anion exchange resin Duolite A-102 D

    Directory of Open Access Journals (Sweden)

    R.S. Lokhande

    2008-04-01

    Full Text Available The study on thermodynamics of ion exchange equilibrium for uni-univalent Cl-/I-, Cl-/Br-, and uni-divalent Cl-/SO42-, Cl-/C2O42- reaction systems was carried out using ion exchange resin Duolite A-102 D. The equilibrium constant K was calculated by taking into account the activity coefficient of ions both in solution as well as in the resin phase. The K values calculated for uni-univalent and uni-divalent anion exchange reaction systems was observed to increase with rise in temperature, indicating the endothermic exchange reactions having enthalpy values of 13.7, 38.0, 23.9, 22.9 kJ/mol, respectively.

  3. Influence of Ga+ ion irradiation on thermal relaxation of exchange bias field in exchange-coupled CoFe/IrMn bilayers

    Institute of Scientific and Technical Information of China (English)

    Qi Xian-Jin; Wang Yin-Gang; Miao Xue-Fei; Li Zi-Quan; Huang Yi-zhong

    2011-01-01

    This paper reports that the CoFe/IrMn bilayers are deposited by magnetron sputtering on the surfaces of thermallyoxidized Si substrates. It investigates the thermal relaxations of both non-irradiated and Ga+ ion irradiated CoFe/IrMn bilayers by means of holding the bilayers in a negative saturation field. The results show that exchange bias field decreases with the increase of holding time period for both non-irradiated and Ga+ ion irradiated CoFe/IrMn bilayers. Exchange bias field is also found to be smaller upon irradiation at higher ion dose. This reduction of exchange bias field is attributed to the change of energy barrier induced by ion-radiation.

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

    Science.gov (United States)

    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(-).

  5. Simulations of ion velocity distribution functions taking into account both elastic and charge exchange collisions

    Science.gov (United States)

    Wang, Huihui; Sukhomlinov, Vladimir S.; Kaganovich, Igor D.; Mustafaev, Alexander S.

    2017-02-01

    Based on accurate representation of the He+-He angular differential scattering cross sections consisting of both elastic and charge exchange collisions, we performed detailed numerical simulations of the ion velocity distribution functions (IVDF) by Monte Carlo collision method (MCC). The results of simulations are validated by comparison with the experimental data of the ion mobility and the transverse diffusion. The IVDF simulation study shows that due to significant effect of scattering in elastic collisions IVDF cannot be separated into product of two independent IVDFs in the transverse and parallel to the electric field directions.

  6. Influence of Acid Etching on Wettability of Ion-exchanged Aluminosilicate Float Glass

    Directory of Open Access Journals (Sweden)

    LI Xiaoyu

    2016-12-01

    Full Text Available The influence of acid etching time on wettability of ion-exchanged aluminosilicate float glass was investigated. The contact angle, roughness and surface composition were measured. The results show that the contact angle increases to a maximum value in the first 7 min and then decreases with the corrosion time. The main reason that cause the change of the contact angle is the change of surface roughness and the content of fluorine atom. The contact angle on the tin side is always larger than that on the air side which is caused by the tin ions on the tin side.

  7. NUMEN Project @ LNS : Heavy Ions Double Charge Exchange as a tool towards the 0νββ Nuclear Matrix Element

    Science.gov (United States)

    Agodi, C.; Cappuzzello, F.; Bonanno, D. L.; Bongiovanni, D. G.; Branchina, V.; Calabrese, S.; Calabretta, L.; Calanna, A.; Carbone, D.; Cavallaro, M.; Colonna, M.; Foti, A.; Finocchiaro, P.; Greco, V.; Lanzalone, G.; Lo Presti, D.; Longhitano, F.; Muoio, A.; Pandola, L.; Rifuggiato, D.; Tudisco, S.

    2016-06-01

    The NUMEN Project, proposed at INFN Laboratori Nazionali del Sud (LNS) in Catania, has the aim to access the nuclear matrix elements, entering the expression of the life time of double beta decay, by relevant cross sections of double charge exchange reactions. The basic point, on which it is based this innovative technique, is the coincidence of the initial and final state wave-functions in the two classes of processes and the similarity of the transition operators. A key aspect of the Project is the use of MAGNEX large acceptance magnetic spectrometer, for the detection of the ejectiles, and of the INFN LNS K800 Superconducting Cyclotron (CS), for the acceleration of the required high resolution and low emittance heavy-ion beams.

  8. PREPARATION AND CHARACTERIZATION OF ION EXCHANGE MEMBRANES BASED ON POLYVINYLIDENE FLUORIDE

    Institute of Scientific and Technical Information of China (English)

    Bo Tian; Chuan-wei Yan; Fu-hui Wang

    2004-01-01

    A new ion exchange membrane based on polyvinylidene fluoride (PVDF) and sulfonated poly(styrenedivinylbenzene) was prepared by in-situ polymerization. The incorporation of sulfonic groups into the polyvinylidene fluoride composite membrane was confirmed by infrared spectroscopy (IR), ion exchange capacity (IEC) and energy dispersive X-ray analysis (EDAX). Area resistance, IEC and water uptake of the treated membrane were evaluated. When area resistance in NaCl aqueous solution at 25℃, IEC is as high as 2.43 millimoles per gram of the wet membrane. The hydrophilicity of PVDF membrane is also significantly improved after treatment. When 60% of crosslinked membrane was sulfonated at 80℃ for 6 h, water uptake of the treated membrane can attain 64.7%.

  9. Interferometric angular characterization of ion-exchanged glass binary phase plates

    Science.gov (United States)

    Moreno, Vicente; Prieto-Blanco, Xesús; Montero, Carlos; Crespo, José; Barral, David; Mouriz, Dolores; Nistal, María C.; Mateo, Eduardo F.; Liñares, Jesús

    2015-04-01

    An interferometric characterization of the phase angular shifting produced by rotation of an ion-exchanged glass binary phase plates is presented. The inverse WKB method is used as a starting point to fabricate the phase plates, because such a method can only characterize the phase shift for normal incidence of the light on the plate. A complete phase angular shifting characterization is made by a Mach-Zehnder interferometer where a four-step phase shifting method is used for acquisition of data and a modified Carre algorithm is applied to data processing. The theoretical phase shifting is calculated by using the phase accumulated by a plane wavefront propagating in an axial graded-index media modelling an ion-exchanged glass phase plate. Experimental results present a good agreement with theoretical predictions.

  10. Fabrication and comprehensive modeling of ion-exchanged Bragg optical add-drop multiplexers.

    Science.gov (United States)

    Castro, Jose M; Geraghty, David F; West, Brian R; Honkanen, Seppo

    2004-11-20

    Optical add-drop multiplexers (OADMs) based on asymmetric Y branches and tilted gratings offer excellent-performance in wavelength-division multiplexed systems. To simplify waveguide fabrication, ion-exchange techniques appear to be an important option in photosensitive glasses. Optimum OADM performance depends on how accurately the waveguide fabrication process and tilted Bragg grating operation are understood and modeled. Results from fabrication and comprehensive modeling are compared for ion-exchange processes that use different angles of the tilted grating. The transmission and reflection spectra for the fabricated and simulated OADMs show excellent agreement. The OADM's performance is evaluated in terms of the measured characteristics of the Y branches and tilted gratings.

  11. Charge exchange and energy loss of slow highly charged ions in 1 nm thick carbon nanomembranes.

    Science.gov (United States)

    Wilhelm, Richard A; Gruber, Elisabeth; Ritter, Robert; Heller, René; Facsko, Stefan; Aumayr, Friedrich

    2014-04-18

    Experimental charge exchange and energy loss data for the transmission of slow highly charged Xe ions through ultrathin polymeric carbon membranes are presented. Surprisingly, two distinct exit charge state distributions accompanied by charge exchange dependent energy losses are observed. The energy loss for ions exhibiting large charge loss shows a quadratic dependency on the incident charge state indicating that equilibrium stopping force values do not apply in this case. Additional angle resolved transmission measurements point on a significant contribution of elastic energy loss. The observations show that regimes of different impact parameters can be separated and thus a particle's energy deposition in an ultrathin solid target may not be described in terms of an averaged energy loss per unit length.

  12. Correlation analysis on partition of rare earth in ion-exchangeable phase from weathered crust ores

    Institute of Scientific and Technical Information of China (English)

    CHI Ru-an; DAI Zu-xu; XU Zhi-gao; WU Yuan-xin; WANG Cun-wen

    2006-01-01

    The rare earth(RE) in weathered crust ores mainly exists as ion-exchangeable phase, approximately 80%. The correlation analysis on partition of 376 samples in ion-exchangeable phase from weathered crust ores was conducted. The results show that partition both among heavy RE elements and light RE elements with high partition appears positive correlation, but partition sums between the heavy RE elements and the light RE elements appear close negative correlation obviously. Clear negative correlations exist between the light RE elements (except Ce) and yttrium(Y). Matrix of correlation analysis on this partition can be divided into three zones. The correlated coefficient variation from negative to positive in zones B and C occurs at Gd, so does that in zones B and A (except Ce, Eu, and Sm), suggesting that RE elements can be divided into two groups with Gd as border. This phenomenon is called Gadolinium-broken effect.

  13. A novel protein refolding method integrating ion exchange chromatography with artificial molecular chaperone

    Institute of Scientific and Technical Information of China (English)

    Qin Ming Zhang; Chao Zhan Wang; Jiang Feng Liu; Li Li Wang

    2008-01-01

    Artificial molecular chaperone (AMC) and ion exchange chromatography (IEC) were integrated, thus a new refolding method,artificial molecular chaperone-ion exchange chromatography (AMC-IEC) was developed. Compared with AMC and IEC, theactivity recovery of lysozyme obtained by AMC-IEC was much higher in the investigated range of initial protein concentrations,and the results show that AMC-IEC is very efficient for protein refolding at high concentrations. When the initial concentration oflysozyme is 180 mg/mL, its activity recovery obtained by AMC-IEC is still as high as 76.6%, while the activity recoveries obtainedby AMC and IEC are 45.6% and 42.4%, respectively.2008 Chao Zhan Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

  14. PVDF based ion exchange membrane prepared by radiation grafting of ethyl styrenesulfonate and sequent hydrolysis

    Science.gov (United States)

    Wang, Yicheng; Peng, Jing; Li, Jiuqiang; Zhai, Maolin

    2017-01-01

    A new synthesis route for poly(vinylidene fluoride)-g-polystyrene sulfonic acid ion exchange membrane (PVDF-g-PSSA IEM) has been developed via preradiation-induced grafting of ethyl styrenesulfonate and sequent hydrolysis. A high grafting yield (GY) 120% for PETSS grafted onto PVDF could be obtained at a reaction time of 3 h and dose of 50 kGy. The structure of PVDF-g-PSSA IEM was testified by FTIR, XPS, TGA and SEM analysis. At the GY above 80%, the ion exchange capacity, water uptake and proton conductivity of the resultant PVDF-g-PSSA IEM exceeds Nafion 117 membrane. This work provides an environmental method for the preparation of the IEM used in fuel cell or water treatment.

  15. Safety Evaluation for Packaging for onsite Transfer of plutonium recycle test reactor ion exchange columns

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R.J.

    1995-09-11

    The purpose of this Safety Evaluation for Packaging (SEP) is to authorize the use of three U.S. Department of Transportation (DOT) 7A, Type A metal boxes (Capital Industries Part No. S 0600-0600-1080- 0104) to package 12 Plutonium Recycle Test Reactor (PRTR) ion exchange columns as low-level waste (LLW). The packages will be transferred from the 309 Building in the 300 Area to low level waste burial in the 200 West Area. Revision 1 of WHC-SD-TP-SEP-035 (per ECN No. 621467) documents that the boxes containing ion exchange columns and grout will maintain the payload under normal conditions of transport if transferred without the box lids

  16. Expanded-bed adsorption utilizing ion-exchange resin to purify extracellular beta-galactosidase.

    Science.gov (United States)

    Pereira, J A; Vieira E Rosa, P De T; Pastore, G M; Santana, C C

    1998-01-01

    The application of expanded-bed ion-exchange resins allows the elimination of intermediary particulate separation steps like filtration or centrifugation prior to adsorption steps in enzyme-purification processes from crude fermentation broths. This work is concerned with the experimental evaluation data of a process related to the adsorption of an extracellular p-galactosidase from the fungi Scopulariopsis. The protein recovery in the ion-exchange resin Accell Plus QMA was accomplished using a continuous-monitoring method. The direct adsorption step was followed by a elution step with concentrated NaCl solutions aiming to improve the enzyme-specific activity. Experimental data for fixed and expanded bed were compared.

  17. Refolding of detergent-denatured lysozyme using β-cyclodextrin-assisted ion exchange chromatography.

    Science.gov (United States)

    Zhang, Li; Zhang, Qinming; Wang, Chaozhan

    2013-03-01

    Chromatography-based protein refolding is widely used. Detergent is increasingly used for protein solubilization from inclusion bodies. Therefore, it is necessary to develop a refolding method for detergent-denatured/solubilized proteins based on liquid chromatography. In the present work, sarkosyl-denatured/dithiothreitol-reduced lysozyme was used as a model, and a refolding method based on ion exchange chromatography, assisted by β-cyclodextrin, was developed for refolding detergent-denatured proteins. Many factors affecting the refolding, such as concentration of urea, concentration of β-cyclodextrin, pH and flow rate of mobile phases, were investigated to optimize the refolding conditions for sarkosyl-denatured lysozymes. The results showed that the sarkosyl-denatured lysozyme could be successfully refolded using β-cyclodextrin-assisted ion exchange chromatography.

  18. Development of treatment process by pyrolysis of low level radioactive spent ion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Nagahara, Satoshi; Kidoguchi, Akira; Ushikoshi, Juntaro; Kanda, Nobuyasu [Mitsui Shipbuilding and Engineering Co. Ltd., Tokyo (Japan)

    2001-03-01

    Mitsui Engineering and Shipbuilding Co., Ltd. has been successfully developing a continuous treatment process by pyrolysis under reduction condition for low level radioactive ion-exchange resin used in nuclear power plants, for the purpose of reducing its volume with excellent decontamination performance. Pyrolysis experiments with labo-scale and bench-scale test equipments were carried out, followed by the continuous pyrolysis treatment test in the full-scale test equipment with feed rate at 7 liter/hour which was composed of a rotary kiln pyrolysis drum and an after-burner. Results showed an excellent performance of pyrolysis for the treatment of the spent resin. The properties of cement immobilization of residue sufficiently meet the governmental regulations, and we are confident that the continuous treatment process of the disposal for the low level radioactive ion-exchange resin used in nuclear power plants is established. (author)

  19. A Simple and Efficient Method for Purification of Egg White Major Proteins Using Ion Exchange Chromatography

    Directory of Open Access Journals (Sweden)

    Sh. Veisi

    2008-04-01

    Full Text Available Introduction & Objective: Egg white contains four high-quantity proteins which have numerous applications. In this research, a simple and efficient method for the purification of those proteins was designed and performed based on ion exchange chromatography.Materials & Methods: In this experimental study egg white was initially separated from insoluble substances by acidic pH. The resulting extract was isolated after two steps of ion exchange chromatography using CM-Sepharose and DEAE-Sepharose columns, respectively. Purification degree and yield of each fraction were analyzed by electrophoresis densitometry.Results: The results showed that purification degrees of ovalbumin, ovotransferrin, ovomucoid and lysozyme were 97, 98, 85 and 99 percent and their yields were 98, 98 95 and 99 percent, respectively.Conclusion: High yields, reproducibility and feasibility on low or high scales are considered as the strengths of this method.

  20. Effect of calcium/sodium ion exchange on the osmotic properties and structure of polyelectrolyte gels.

    Science.gov (United States)

    Horkay, Ferenc; Basser, Peter J; Hecht, Anne-Marie; Geissler, Erik

    2015-12-01

    We discuss the main findings of a long-term research program exploring the consequences of sodium/calcium ion exchange on the macroscopic osmotic and elastic properties, and the microscopic structure of representative synthetic polyelectrolyte (sodium polyacrylate, (polyacrylic acid)) and biopolymer gels (DNA). A common feature of these gels is that above a threshold calcium ion concentration, they exhibit a reversible volume phase transition. At the macroscopic level, the concentration dependence of the osmotic pressure shows that calcium ions influence primarily the third-order interaction term in the Flory-Huggins model of polymer solutions. Mechanical tests reveal that the elastic modulus is practically unaffected by the presence of calcium ions, indicating that ion bridging does not create permanent cross-links. At the microscopic level, small-angle neutron scattering shows that polyacrylic acid and DNA gels exhibit qualitatively similar structural features in spite of important differences (e.g. chain flexibility and chemical composition) between the two polymers. The main effect of calcium ions is that the neutron scattering intensity increases due to the decrease in the osmotic modulus. At the level of the counterion cloud around dissolved macroions, anomalous small-angle X-ray scattering measurements made on DNA indicate that divalent ions form a cylindrical sheath enveloping the chain, but they are not localized. Small-angle neutron scattering and small-angle X-ray scattering provide complementary information on the structure and interactions in polymer solutions and gels.

  1. Characterization of poly(allylamine) as a polymeric ligand for ion-exchange protein chromatography.

    Science.gov (United States)

    Li, Ming; Li, Yanying; Yu, Linling; Sun, Yan

    2017-02-24

    This work reports poly(allylamine) (PAA), as a polymeric ion-exchange ligand for protein chromatography. Sepharose FF was modified with PAA, and six anion exchangers with ionic capacities (ICs) from 165 to 618mmol/L were prepared. Inverse size exclusion chromatography, adsorption equilibrium, uptake kinetics and column elution were performed. It was found that both the adsorption capacity and effective diffusivity maintained low values in the IC range of 165-373mmol/L, but they started to increase beyond 373mmol/L, and increased by 80% and 23 times, respectively, when the IC reached 618mmol/L. Interestingly, a drastic decrease of pore size was observed around the IC of 373mmol/L. The results suggest that the PAA chains played an important role in protein adsorption by altering the inner pore structure of the gels. It is considered that, PAA chains turn from inextensible states with multipoint-grafting on the pore surface at low coupling densities (IC373mmol/L). These characters of the grafted chains at higher IC values benefit in protein adsorption by three-dimensional binding and encouraged the happening of "chain delivery" of bound proteins on the chains. Besides, the ion exchangers showed favorable adsorption and uptake properties in a wide ionic strength range, 0-500mmol/L NaCl, indicating much better salt tolerance feature than the so-far reported ion exchangers. Moreover, a mild condition of pH 5.0 offered effective recovery of bound proteins in elution chromatography. The results indicate that the PAA-based anion exchanger of a high IC value is promising for high-capacity protein chromatography dealing with feedstock of a wide range of ionic strengths.

  2. A conditioning process for ion exchanger resins contaminated with radioactive elements. Procede de conditionnement de resines echangeuses d'ions contaminees par des elements radioactifs

    Energy Technology Data Exchange (ETDEWEB)

    Legros, R.; Wiegert, B.; Zeh, J.L.

    1993-08-20

    Ion exchanger resins are embedded in a pre-polymer syrup prepared from acrylic monomers having high boiling point. A curing catalyst (a peroxide) and an activation agent (a tertiary amine) are added. 12 examples are given. 9 p.

  3. Repeated use of ion-exchange resin membranes in calcareous soils

    Science.gov (United States)

    Sherrod, S.K.; Belnap, J.; 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. Solvent and irradiation doses effects on the ion exchange capacity of sulfonated styrene grafted PVDF

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Henrique P.; Parra, Duclerc F.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Polymers exhibiting ion exchange capacity are studied for many years due to their application in several fields, such as membranes for proton exchange fuel cells, filtration membranes, heavy ions recovery and artificial muscles and sensors. Radiation induced grafting followed by sulfonation is a well-known way to obtain ion exchange polymers. Fluorinated polymers are frequently used as polymeric matrix for grafting due to their excellent physicochemical properties. Radiation induced grafting of styrene into poly (vinylidene fluoride) (PVDF) by simultaneous method in 1:1 styrene/toluene or styrene/N,N-dimethylformamide solutions was studied. Irradiations were performed under nitrogen atmosphere, room temperature and at doses of 5, 10 and 20 kGy with dose rate of 5 kGy.h{sup -1} from a {sup 60}Co gamma source. After washing, grafted materials were sulfonated in 10% chlorosulfonic acid/1,2-dichloroethane solutions for 4 h at room temperature. Characterization shows that increasing irradiation dose corresponds to increases in the grafting yield (GY %) gravimetrically calculated and these different solvents shows different grafting behaviors. Toluene allows no more than 3 % of grafting while DMF allows up to 55 % of grafting in the same condition. Grafting in toluene solution occurs on the surface and in DMF solution it occurs in the bulk, as confirmed by SEM. Both irradiation doses and solvent used have direct effects in the ion exchange capacities (calculated after titrations). FT-IR spectra exhibit new peaks after grafting and after sulfonation, attributed to grafted monomer and sulfonic groups attached to the styrene. DSC shows differences in thermal behavior of the polymer before and after each step. (author)

  5. Buried ion-exchanged glass waveguides: burial-depth dependence on waveguide width.

    Science.gov (United States)

    Madasamy, P; West, B R; Morrell, M M; Geraghty, D F; Honkanen, S; Peyghambarian, N

    2003-07-01

    A detailed theoretical and experimental study of the depth dependence of buried ion-exchanged waveguides on waveguide width is reported. Modeling, which includes the effect of nonhomogeneous time-dependent electric field distribution, agrees well with our experiments showing that burial depth increases linearly with waveguide width. These results may be used in the proper design of integrated optical circuits that need waveguides of different widths at different sections, such as arrayed waveguide gratings.

  6. Effect of thermochemical treatment on the surface morphology and hydrophobicity of heterogeneous ion-exchange membranes

    Science.gov (United States)

    Vasil'eva, V. I.; Pismenskaya, N. D.; Akberova, E. M.; Nebavskaya, K. A.

    2014-08-01

    A comparative analysis is performed on the effect thermochemical treatment in aqueous, alkali, and acid media has on the surface morphology and hydrophobicity of swelling heterogeneous ion-exchanged membranes. A correlation between changes in surface morphology and hydrophobicity is established. It is shown that under prolonged (50 h) membrane thermal treatment above room temperature, hydrophobicity is reduced due to substantial enlargement of cavities and cracks resulting from the partial destruction of inert binder (polyethylene) and reinforcing poly-ɛ-caproamide fabric (capron).

  7. Development and properties of crystalline silicotitanate (CST) ion exchangers for radioactive waste applications

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.E.; Brown, N.E.

    1997-04-01

    Crystalline silicotitanates (CSTs) are a new class of ion exchangers that were jointly invented by researchers at Sandia National Laboratories and Texas A&M University. One particular CST, known as TAM-5, is remarkable for its ability to separate parts-per-million concentrations of cesium from highly alkaline solutions (pH> 14) containing high sodium concentrations (>5M). It is also highly effective for removing cesium from neutral and acidic solutions, and for removing strontium from basic and neutral solutions. Cesium isotopes are fission products that account for a large portion of the radioactivity in waste streams generated during weapons material production. Tests performed at numerous locations with early lab-scale TAM-5 samples established the material as a leading candidate for treating radioactive waste volumes such as those found at the Hanford site in Washington. Thus Sandia developed a Cooperative Research and Development Agreement (CRADA) partnership with UOP, a world leader in developing, commercializing, and supplying adsorbents and associated process technology to commercialize and further develop the material. CSTs are now commercially available from UOP in a powder (UOP IONSIV{reg_sign} IE-910 ion exchanger) and granular form suitable for column ion exchange operations (UOP IONSIV{reg_sign} IE-911 ion exchanger). These materials exhibit a high capacity for cesium in a wide variety of solutions of interest to the Department of Energy, and they are chemically, thermally, and radiation stable. They have performed well in tests at numerous sites with actual radioactive waste solutions, and are being demonstrated in the 100,000 liter Cesium Removal Demonstration taking place at Oak Ridge National Laboratory with Melton Valley Storage Tank waste. It has been estimated that applying CSTs to the Hanford cleanup alone will result in a savings of more than $300 million over baseline technologies.

  8. Photocatalytic reduction of nitrate using titanium dioxide for regeneration of ion exchange brine

    OpenAIRE

    Yang,Ting; Doudrick, Kyle; Westerhoff, Paul

    2012-01-01

    Nitrate is often removed from groundwater by ion exchange (IX) before its use as drinking water. Accumulation of nitrate in IX brine reduces the efficiency of IX regeneration and the useful life of the regeneration brine. For the first time, we present a strategy to photocatalytically reduce nitrate in IX brine, thereby extending the use of the brine. Titanium dioxide (Evonik P90), acting as photocatalyst, reduced nitrate effectively in both synthetic brines and sulfate-removed IX brine when ...

  9. Thermal potential of ion-exchange membranes and its application to thermoelectric power generation

    OpenAIRE

    Jokinen, Miikka; Manzanares Andreu, Jose; Kontturi, Kyösti; Murtomäki, Lasse

    2016-01-01

    The low efficiency and high price of thermoelectric semiconductors has generated interest in unconventional forms of thermoelectric materials. In this article, ionic thermoelectricity has been studied with commercial ion-exchange membranes for different aqueous 1:1 electrolytes. The theory of thermal membrane potential has been derived taking into account the ionic heats of transport, the non-isothermal Donnan potentials, the temperature polarization, and the thermally-induced concentration p...

  10. Influence of the Functionalization Degree of Acidic Ion-Exchange Resins on Ethyl Octyl Ether Formation

    OpenAIRE

    Guilera, J.; Hanková, L. (Libuše); Jeřábek, K.; E Ramírez; Tejero, J.

    2014-01-01

    Ethyl octyl ether (EOE) can be obtained by the ethylation of 1-octanol by means of ethanol or diethyl carbonate over acidic ion-exchange resins. However, EOE formation has to compete with the less steric demanding formation of diethyl ether, by-product obtained from ethanol dehydration or diethyl carbonate decomposition. In the present work, the influence of the resin functionalization degree on EOE formation has been evaluated. A series of partially sulfonated resins were prepared by the sul...

  11. Unified superresolution experiments and stochastic theory provide mechanistic insight into protein ion-exchange adsorptive separations

    OpenAIRE

    Kisley, Lydia; Chen, Jixin; Mansur, Andrea P.; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Chen, Wen-Hsiang; Dhamane, Sagar; Willson, Richard C.; Landes, Christy F.

    2014-01-01

    Adsorption of proteins underlies the purification of biopharmaceuticals, as well as therapeutic apheresis, immunoassays, and biosensors. In particular, separation of proteins by interactions with charged ligands on surfaces (ion-exchange chromatography) is an essential tool of the modern pharmaceutical industry. By quantifying the interactions of single proteins with individual charged ligands, we demonstrate that clusters of charges are necessary to create functional adsorption sites and tha...

  12. Perchlorate Selectivity of Anion Exchange Resins as Evaluated Using Ion-Selective Electrodes.

    Science.gov (United States)

    Yamamoto, Kenji; Mitsuda, Shin'ya; Ohtake, Naomi; Murashige, Natsuki; Ohmuro, Satoshi; Yuchi, Akio

    2017-01-01

    The selectivity coefficients reported for perchlorate of the high selectivity on anion exchange resins (AXRs) have not been consistent with one another. Possible errors by the unique use of four parameters (concentrations of two anions in two phases) were experimentally verified. The concentrations of perchlorate buffered at low levels (10(-6) - 10(-4) mol L(-1)) by two forms of AXRs were successfully determined by potentiometry with a perchlorate ion-selective electrode. This gave reasonable coefficients. The coefficients for perchlorate on several AXRs were independent of the relative exchange (RE), in contrast to the previous reports. On the other hand, the coefficients for fluoride of the low selectivity that were examined for comparison decreased with an increase in RE, and the dependency was more remarkable for the resins of large exchange capacity.

  13. Simulation model for overloaded monoclonal antibody variants separations in ion-exchange chromatography.

    Science.gov (United States)

    Guélat, Bertrand; Ströhlein, Guido; Lattuada, Marco; Delegrange, Lydia; Valax, Pascal; Morbidelli, Massimo

    2012-08-31

    A model was developed for the design of a monoclonal antibody charge variants separation process based on ion-exchange chromatography. In order to account for a broad range of operating conditions in the simulations, an explicit pH and salt concentration dependence has been included in the Langmuir adsorption isotherm. The reliability of this model was tested using experimental chromatographic retention times as well as information about the structural characteristics of the different charge variants, e.g. C-terminal lysine groups and deamidated groups. Next, overloaded isocratic elutions at various pH and salt concentrations have been performed to determine the saturation capacity of the ion-exchanger. Furthermore, the column simulation model was applied for the prediction of monoclonal antibody variants separations with both pH and salt gradient elutions. A good prediction of the elution times and peak shapes was observed, even though none of the model parameters was adjusted to fit the experimental data. The trends in the separation performance obtained through the simulations were generally sufficient to identify the most promising operating conditions. The predictive column simulation model thus developed in this work, including a set of parameters determined through specific independent experiments, was experimentally validated and offers a useful basis for a rational optimization of monoclonal antibody variants separation processes on ion-exchange chromatography.

  14. Boron Separation by the Two-step Ion-Exchange for the Isotopic Measurement of Boron

    Institute of Scientific and Technical Information of China (English)

    WANG,Qing-Zhong(王庆忠); XIAO,Ying-Kai(肖应凯); WANG,Yun-Hui(王蕴惠); ZHANG,Chong-Geng(张崇耿); WEI,Hai-Zhen(魏海珍)

    2002-01-01

    An improved procedure for extraction and purification of boron from natural samples is presented. The separation and purification of boron was carried out using a boron-specific resin, Amberlite IRA743, and a mixed ion exchange resin,Dowex 50W × 8 and Ion Exchanger Ⅱ resin. Using the mixed ion exchange resin which adsorbs all cations and anions except boron, the HCl and other cations and anions left in eluant from the Amberlite IRA 743 were removed effectively. In this case, boron loss can be avoided because the boron-bearing solution does not have to be evaporated to reach dryness to dislodge HCl. The boron recovery ranged from 97.6% to 102% in this study. The isotopic fractionation of boron can be negligible within the precision of the isotopic measurement. The results show that boron separation for the isotopic measurement by using both Amberlite IRA 743 resin and the mixed rein is more effective than that using Amberlite IRA 743 resin alone. The boron in samples of brine, seawater, rock, coral and foraminifer were separated by this procedure. Boron isotopic compositions of these samples were measured by thermal ionization mass spectrometry in this study.

  15. Selective adsorption of thiophene and 1-benzothiophene on metal-ion-exchanged zeolites in organic medium.

    Science.gov (United States)

    Xue, Mei; Chitrakar, Ramesh; Sakane, Kohji; Hirotsu, Takahiro; Ooi, Kenta; Yoshimura, Yuji; Feng, Qi; Sumida, Naoto

    2005-05-15

    Adsorption of the organic sulfur compounds thiophene (TP) and 1-benzothiophene (1-BTP) in an organic model solution of hydrodesulfurizated gasoline (heptane with 1 wt% toluene and 0.156 mM (5 ppmw as sulfur) TP or 1-BTP) was studied by a batch method at 80 degrees C using metal-ion-exchanged Y-zeolites. Although NaY-zeolite or its acid-treated material rarely adsorbed the organic sulfur compounds, NaY-zeolites exchanged with Ag+, Cu2+, and Ce3+ ions and NH(4)Y-zeolites exchanged with Ce3+ ions showed markedly high adsorptive capacities for TP and 1-BTP. The sulfur uptake increased in the order CuY-zeolite(Na)

  16. Regeneration of Ion-Exchanging Resin%离子交换树脂的再生

    Institute of Scientific and Technical Information of China (English)

    周潇

    2011-01-01

    Desalination by ion exchange is widely used in purifying water for boiler. Regeneration of ion-exchanging resin is a complication process ,and regeneration results are affected by regeneration concentration, velocity and time. In this paper, on the basis of summarizing regeneration experiences of the desalination system in Guangxi Hechi chemical company, regeneration process was studied, which can provide some references for other enterprises which adopt ion-exchanging process.%离子交换法除盐在锅炉给水除盐工艺中有广泛地应用,离子交换树脂的再生是一个复杂的过程,再生浓度、流速和时间等都会影响再生的效果.在总结广西河池化工股份有限公司除盐水系统再生经验的基础上,对再生工艺进行了研究,为采用离子交换法除盐的企业提供借鉴.

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

    Science.gov (United States)

    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.

  18. Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification

    Science.gov (United States)

    Ferraz, Natalia; Carlsson, Daniel O.; Hong, Jaan; Larsson, Rolf; Fellström, Bengt; Nyholm, Leif; Strømme, Maria; Mihranyan, Albert

    2012-01-01

    Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m2 g−1) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 μmol g−1 in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 μmol g−1 in an isotonic solution. The heparinized PPy–cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility. PMID:22298813

  19. Unified superresolution experiments and stochastic theory provide mechanistic insight into protein ion-exchange adsorptive separations.

    Science.gov (United States)

    Kisley, Lydia; Chen, Jixin; Mansur, Andrea P; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Chen, Wen-Hsiang; Dhamane, Sagar; Willson, Richard C; Landes, Christy F

    2014-02-11

    Chromatographic protein separations, immunoassays, and biosensing all typically involve the adsorption of proteins to surfaces decorated with charged, hydrophobic, or affinity ligands. Despite increasingly widespread use throughout the pharmaceutical industry, mechanistic detail about the interactions of proteins with individual chromatographic adsorbent sites is available only via inference from ensemble measurements such as binding isotherms, calorimetry, and chromatography. In this work, we present the direct superresolution mapping and kinetic characterization of functional sites on ion-exchange ligands based on agarose, a support matrix routinely used in protein chromatography. By quantifying the interactions of single proteins with individual charged ligands, we demonstrate that clusters of charges are necessary to create detectable adsorption sites and that even chemically identical ligands create adsorption sites of varying kinetic properties that depend on steric availability at the interface. Additionally, we relate experimental results to the stochastic theory of chromatography. Simulated elution profiles calculated from the molecular-scale data suggest that, if it were possible to engineer uniform optimal interactions into ion-exchange systems, separation efficiencies could be improved by as much as a factor of five by deliberately exploiting clustered interactions that currently dominate the ion-exchange process only accidentally.

  20. Unified superresolution experiments and stochastic theory provide mechanistic insight into protein ion-exchange adsorptive separations

    Science.gov (United States)

    Kisley, Lydia; Chen, Jixin; Mansur, Andrea P.; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Chen, Wen-Hsiang; Dhamane, Sagar; Willson, Richard C.; Landes, Christy F.

    2014-01-01

    Chromatographic protein separations, immunoassays, and biosensing all typically involve the adsorption of proteins to surfaces decorated with charged, hydrophobic, or affinity ligands. Despite increasingly widespread use throughout the pharmaceutical industry, mechanistic detail about the interactions of proteins with individual chromatographic adsorbent sites is available only via inference from ensemble measurements such as binding isotherms, calorimetry, and chromatography. In this work, we present the direct superresolution mapping and kinetic characterization of functional sites on ion-exchange ligands based on agarose, a support matrix routinely used in protein chromatography. By quantifying the interactions of single proteins with individual charged ligands, we demonstrate that clusters of charges are necessary to create detectable adsorption sites and that even chemically identical ligands create adsorption sites of varying kinetic properties that depend on steric availability at the interface. Additionally, we relate experimental results to the stochastic theory of chromatography. Simulated elution profiles calculated from the molecular-scale data suggest that, if it were possible to engineer uniform optimal interactions into ion-exchange systems, separation efficiencies could be improved by as much as a factor of five by deliberately exploiting clustered interactions that currently dominate the ion-exchange process only accidentally. PMID:24459184