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Sample records for adjustment ion exchange

  1. Natural ion exchangers

    Present article is devoted to natural ion exchangers. Ion exchange properties of minerals are described. Structural types of porous matrixes of natural ion exchangers are considered. Types of sorption centres in minerals are considered as well.

  2. Ion exchange equilibrium constants

    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

  3. Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores

    The uranium recovery from acid leach solutions of uranium-phosphate ores has been studied. Relations have been found between the solution characteristics and the results obtained at different stages of the process. The following data can thus be predicted: solids to remove and uranium recovery in the pH adjustment stage, uranium capacity of the resin, more suitable eluating agent, elution velocity and uranium concentration in the eluate in the ion exchange stage, and composition of the concentrate produced by direct precipitation of the eluate in the concentrate precipitation stage. (Author) 8 refs

  4. Ion exchange phenomena

    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).

  5. Analytical applications of ion exchangers

    Inczédy, J

    2013-01-01

    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

  6. Ion exchange technology assessment report

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

  7. Electrically switched ion exchange

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

    1997-10-01

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

  8. A Colorful Ion Exchange Experiment

    Mendes, Adélio

    1999-11-01

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

  9. Graphene/Ionic Liquid Composite Films and Ion Exchange

    Yufei Mo; Yunfang Wan; Alicia Chau; Fuchuan Huang

    2014-01-01

    Wettability of graphene is adjusted by the formation of various ionic surfaces combining ionic liquid (IL) self-assembly with ion exchange. The functionalized ILs were designed and synthesized with the goal of obtaining adjustable wettability. The wettability of the graphene surface bearing various anions was measured systematically. The effect of solvent systems on ion exchange ratios on the graphene surface has also been investigated. Meanwhile, the mechanical properties of the graphene/IL ...

  10. Solidification method for spent ion exchange resin

    A hydrophilic binder having a binder effect increased upon contact with water and a cellulose type fibrous binder for reinforcement are added each in an appropriate amount to spent ion exchange resins in a state moistened with water. After the water content of the mixture is appropriately adjusted, they are pelletized by press molding or extrusion molding. With such procedures, less swelling product are obtained which can be solidified into stable products. (T.M.)

  11. SPEEDUPtrademark ion exchange column model

    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 SpeedUptrademark 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 SuperLigtrademark ion exchange resins, once the experimental data are complete

  12. A Simple Apparatus for Fast Ion Exchange Separations

    An apparatus suitable for very fast ion exchange group separations in radiochemistry has been elaborated. The apparatus which consists of a system of glass tubes with pistons driven by the same force, allows the exact adjustment of influent solutions to a long series of ion-exchange columns. The practical application of the apparatus to the simultaneous separation of six groups of trace elements in the neutron activation analysis of biological material is described

  13. Ion exchange purification of scandium

    Herchenroeder, Laurie A.; Burkholder, Harvey R.

    1990-10-23

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

  14. 225-B ion exchange piping design documentation

    Prather, M.C. [ICF Kaiser Hanford Co., Richland, WA (United States)

    1996-02-01

    This document describes the interface between the planned permanent ion exchange piping system and the planned portable ion exchange system. This is part of the Waste Encapsulation and Storage Facility (WESF). In order to decouple this WESF from B-Plant and to improve recovery from a capsule leak, contaminated pool cell water will be recirculated through a portable ion exchange resin system.

  15. 225-B ion exchange piping design documentation

    This document describes the interface between the planned permanent ion exchange piping system and the planned portable ion exchange system. This is part of the Waste Encapsulation and Storage Facility (WESF). In order to decouple this WESF from B-Plant and to improve recovery from a capsule leak, contaminated pool cell water will be recirculated through a portable ion exchange resin system

  16. Electrically controlled cesium ion exchange

    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.

  17. The Adjustment of Prices and the Adjustment of the Exchange Rate

    Charles Engel; James Morley

    2001-01-01

    The purchasing power parity puzzle relates to the adjustment of real exchange rates. Real exchange rates are extremely volatile, suggesting that temporary shocks emanate from the monetary sector. But the half-life of real exchange rate deviations is extremely large -- 2.5 to 5 years. This half-life seems too large to be explained by the slow adjustment of nominal prices. We offer a different interpretation. We maintain that nominal exchange rates and prices need not converge at the same rate,...

  18. PRTR ion exchange vault column sampling

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

  19. Ion exchange investigation on the Syrian zeolite

    We have studied the ion exchange process by using Syrian zeolite from the region of Tell-Assis with four solutions containing these ions: Ag+, NH4+, Pb2+, and Cu2+. It was found that the required time to reach the equilibrium is 6-8 hours, and depends on the type of ion. the exchange capacity mainly depends on the type of ions, and range between 0.5-1.57 m. mol/g. The effect of pH on ion exchange capacity was obvious and the best results were reached when the pH ranged between 5+ will exchange with univalent and bivalent ions in the zeolite, whereas the bivalent ions as Pb+2 will preferentially exchange with the bivalent ions in the zeolite. we concluded that the used zeolite gave good results compared with some known zeolite. (Author)

  20. Behaviour of the pH adjustment, Ion exchange and concentrate precipitation stages in the acid leaching of uranium phosphate ores; Tratamiento de disoluciones de lixiviacion de minerales de uranio en presencia de fosfatos. Comportamiento en las etapas de ajuste de PH, cambio de ion y precipitacion de concentrados

    Estrada Aguilar, J.; Uriarte Hueda, A.

    1962-07-01

    The uranium recovery from acid leach solutions of uranium-phosphate ores has been studied. Relations have been found between the solution characteristics and the results obtained at different stages of the process. The following data can thus be predicted: solids to remove and uranium recovery in the pH adjustment stage, uranium capacity of the resin, more suitable eluating agent, elution velocity and uranium concentration in the eluate in the ion exchange stage, and composition of the concentrate produced by direct precipitation of the eluate in the concentrate precipitation stage. (Author) 8 refs.

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

    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"…

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

    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. PMID:25929073

  3. Ion exchange in the nuclear industry

    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

  4. Adsorption on mixtures of ion exchangers

    A theoretical study has been made of adsorption on mixtures of ion exchangers. The effect of variables such as the concentration of the ion being adsorbed, the concentration of the supporting electrolyte, loading, the values of the capacities and equilibrium constants for the various exchange processes, and the fraction of each adsorber in the mixture on the observed distribution coefficient has been investigated. A computer program has been written to facilitate the calculation of distribution coefficients for the adsorption of an ion on a given mixture of ion exchangers under a specified set of conditions

  5. Decomposing method for ion exchange resin

    The present invention concerns a method of decomposing ion exchange resins generated in a nuclear power plant to carbon dioxide reliably in a short period of time. (1) The ion exchange resins are mixed with water, and then they are kept for a predetermined period of time in the presence of an inert gas at high temperature and high pressure exceeding the critical point of water to decompose the ion exchange resins. (2) The ion exchange resins is mixed with water, an oxidant is added and they are kept for a predetermined time in the presence of an inert gas at a high temperature and a high pressure exceeding a critical point of water of an inert gas at a high temperature to decompose the ion exchange resins. (3) An alkali or acid is added to ion exchange resins and water to control the hydrogen ion concentration in the solution and the ion exchange resins are decomposed in above-mentioned (1) or (2). Sodium hydroxide is used as the alkali and hydrochloric acid is used as the acid. In addition, oxygen, hydrogen peroxide or ozone is used as an oxidant. (I.S.)

  6. Graphene/Ionic Liquid Composite Films and Ion Exchange

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

    2014-06-01

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

  7. Biodegradation of ion-exchange media

    Ion-exchange media, both bead resins and powdered filter media, are used in nuclear power plants to remove radioactivity from process water prior to reuse or environmental discharge. Since the ion- exchange media are made from synthetic hydrocarbon-based polymers, they may be susceptible to damage from biological activity. The purpose of this study was to investigate some of the more basic aspects of biodegradation of ion-exchange media, specifically to evaluate the ability of microorganisms to utilize the ion-exchange media or materials sorbed on them as a food source. The ASTM-G22 test, alone and combined with the Bartha Pramer respirometric method, failed to indicate the biodegradability of the ion-exchange media. The limitation of these methods was that they used a single test organism. In later phases of this study, a mixed microbial culture was grown from resin waste samples obtained from the BNL High Flux Beam Reactor. These microorganisms were used to evaluate the susceptibility of different types of ion-exchange media to biological attack. Qualitative assessments of biodegradability were based on visual observations of culture growths. Greater susceptibility was associated with increased turbidity in solution indicative of bacterial growth, and more luxuriant fungal mycelial growth in solution or directly on the ion-exchange resin beads. 21 refs., 9 figs., 18 tabs

  8. Cesium ion exchange kinetics with PAN-KCoFC composite ion exchanger

    Moon, Jei Kwong; Han, Yoon Ju; Lee, Eil Hee; Jung, Chong Hun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Lee, Byung Chul [Hannam University, Taejon (Korea, Republic of)

    2004-07-01

    PAN based inorganic-organic composite ion exchanger beads are recently reviewed as promising one for removal of radionuclides due to their characterizing advantages, no dissolution in liquid solution and no pressure drop problem in column operation, over the existing inorganic ion exchangers such as zeolites. Also since the PAN acts as an inert binder all radionuclides are bound to inorganic materials. Therefore no radionuclides release occurs even when they are decomposed underground. In this study, ion exchange kinetics for cesium ion was performed using a PAN-KCoFC composite ion exchanger in a batch reactor together with column system.

  9. Cesium ion exchange kinetics with PAN-KCoFC composite ion exchanger

    PAN based inorganic-organic composite ion exchanger beads are recently reviewed as promising one for removal of radionuclides due to their characterizing advantages, no dissolution in liquid solution and no pressure drop problem in column operation, over the existing inorganic ion exchangers such as zeolites. Also since the PAN acts as an inert binder all radionuclides are bound to inorganic materials. Therefore no radionuclides release occurs even when they are decomposed underground. In this study, ion exchange kinetics for cesium ion was performed using a PAN-KCoFC composite ion exchanger in a batch reactor together with column system

  10. Thermal stability of ion-exchange resins

    The action of heat, radiation and oxidants on carbonchain polymers, such as ion-exchange resins, often cause irreversible chemical changes in macro molecules. These changes can be e g the rupture of the carbon-carbon single or double bond, and/or the degradation of the macro molecule. Ion-exchange materials also contain the far less stable bonds between functional groups and the polymer matrix. For this reason the thermal stability of ion-exchange mat- erials is mainly based on the behaviour of the functional groups, which are responsible for the ion-exchange. The solidification of the ion-exchange resin waste usually involves elevated tempera- tures. Bituminization is carried out at 130-160 degrees C. Cementa- tion is carried out at room temperature. However, cementation can generate temperatures of up to 100-120 degrees C in the solidifica- tion product during the curing period. In this study the swelling/ shrinking properties of different ion-exchange materials have been studied in air and water as a function of the drying time and temp- erature. The air dried resins were used as the reference material. The effect of sodium sulphate as a possible additive to reduce swelling was studied, The experiments which were performed and re- sults observed are discussed in detail in the Appendices. (Authors)

  11. Inorganic ion exchangers for nuclear waste remediation

    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.

  12. Cesium separation Using Electrically Switched Ion Exchange

    Electrically Switched Ion Exchange (ESIX) is a separation technology being developed at Pacific Northwest National Laboratory as an alternative to conventional ion exchange for removing metal ions from wastewater. In ESIX, which combines ion exchange and electro-chemistry, ion uptake and elution can be controlled directly by modulating the potential of an ion exchange film that has been electrochemically deposited onto an electrode. This paper presents the results of experiments on high surface area electrodes and the development of a flow system for cesium ion separation. Bench-scale flow system studies showed no change in capacity or performance of the ESIX films at a flow rate up to 113 BV/h, the maxi-mum flow rate tested, and breakthrough curves supported once-through waste processing. A comparison of results for a stacked 5-electrode cell versus a single-electrode cell showed enhanced breakthrough performance. In the stacked configuration, break-through began at about 120 BV for a feed containing 0.2 ppm cesium at a flow rate of 13 BV/h. A case study for the KE Basin (a spent nuclear fuel storage basin) on the Hanford Site demonstrated that KE Basin wastewater could be processed continuously with minimal waste generation, reduced disposal costs, and lower capital expenditures

  13. Exchange Rates and Fiscal Adjustments: Evidence from the OECD and Implications for EMU

    2003-01-01

    We study monetary and exchange-rate policies around successful and unsuccessful fiscal adjustments and find that successful adjustments are preceded by large nominal exchange rate depreciations, whereas unsuccessful adjustments are preceded by appreciations. Pre-adjustment depreciation is a significant and quantitatively important predictor of the success of adjustment. Our results are robust to the inclusion of other determinants of the success of adjustment and to the definition of the depr...

  14. Method of processing spent ion exchange resins

    Purpose: To decrease the amount of radioactive spent ion exchange resins generated from nuclear power plants, etc and process them into stable inorganic compounds through heat decomposition. Method: Spent ion exchange resins are heat-decomposed in an inert atmosphere to selectively decompose only ion exchange groups in the preceeding step while high molecular skeltons are completely heat-decomposed in an oxidizing atmosphere in the succeeding step. In this way, gaseous sulfur oxides and nitrogen oxides are generated in the preceeding step, while gaseous carbon dioxide and hydrogen requiring no discharge gas procession are generated in the succeeding step. Accordingly, the amount of discharged gases requiring procession can significantly be reduced, as well as the residues can be converted into stable inorganic compounds. Further, if transition metals are ionically adsorbed as the catalyst to the ion exchange resins, the ion exchange groups are decomposed at 130 - 300 0C, while the high molecular skeltons are thermally decomposed at 240 - 300 0C. Thus, the temperature for the heat decomposition can be lowered to prevent the degradation of the reactor materials. (Kawakami, Y.)

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

    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. Electrodialytic decontamination of spent ion exchange resins

    Development of a novel electrodialytic decontamination process for the selective removal of radioactive Cs from spent ion exchange resins containing large amounts of Li is described. The process involves passage of a dc electric current through a bed of the spent ion exchange resin in a specially designed electrodialytic cell. The radiocesium so removed from a volume of the spent resin is concentrated onto a much smaller volume of a Cs selective sorbent to achieve a significant radioactive waste volume reduction. Technical feasibility of the electrodialytic resin decontamination process has been demonstrated on a bench scale with a batch of simulated spent ion exchange resin and using potassium cobalt ferrocyanide as the Cs selective sorbent. A volume reduction factor between 10 and 17 has been estimated. The process appears to be economically attractive. Improvements in process economics can be expected from optimization of the process. Other possible applications of the EDRD process have been identified

  17. Modeling of Crystalline Silicotitanate Ion Exchange Columns

    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 ampersand 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

  18. Dissecting the PPP Puzzle: The Unconventional Roles of Nominal Exchange Rate and Price Adjustments

    Yin-wong Cheung; Lai, Kon S.; Michael Bergman

    2003-01-01

    The conventional view, as expounded by sticky-price models, is that price adjustment determines the PPP reversion rate. This study examines the mechanism by which PPP deviations are corrected. Nominal exchange rate adjustment, not price adjustment, is shown to be the key engine governing the speed of PPP convergence. Moreover, nominal exchange rates are found to converge much more slowly than prices. With the reversion being driven primarily by nominal exchange rates, real exchange rates also...

  19. Dissecting the PPP Puzzle: The Unconventional Roles of Nominal Exchange Rate and Price Adjustment

    Cheung, Yin-Wong; Lai, Kon S.; BERGMAN, MICHAEL

    2003-01-01

    The conventional view, as expounded by sticky-price models, is that price adjustment determines the PPP reversion rate. This study examines the mechanism by which PPP deviations are corrected. Nominal exchange rate adjustment, not price adjustment, is shown to be the key engine governing the speed of PPP convergence. Moreover, nominal exchange rates are found to converge much more slowly than prices. With the reversion being driven primarily by nominal exchange rates, real exchange rates also...

  20. Radiation degradation in organic ion exchange resins

    The EPICOR-2 Resin/Liner Investigation: Low-Level Waste Data Base Development Program, funded by the US Nuclear Regulatory Commission, studied the degradation effects in EPICOR-II organic ion exchange resins caused by internal radiation. Results of the third sampling analysis of ion exchange resins from prefilters PF-8 and PF-20 are compared with baseline data from tests performed on unirradiated resins and with results from the first and second samplings to determine if degradation has occurred because of the high internal radiation dose. Those results are also compared to findings of other researchers

  1. Contamination weeping: A chemical ion exchange model

    Experiments have been conducted to determine the applicability of a chemical ion-exchange model to characterize the problem of nuclear fuel transportation cask contamination and release (''weeping''). Surface charge characteristics of Cr2O3 and stainless steel (304) powders have been measured to determine the potential for ion exchange at metal oxide -- aqueous interfaces. The solubility of pool contaminant Co and Cs electrolytes at varying pH and the adsorption characteristics of these ions on Cr2O3 and stainless steel powders in aqueous slurries have been studied. Experiments show that Co ions do reversibly adsorb on these powder surfaces and, more specifically, that adsorption occurs in the nominal pH range (pH = 4--6) of a boric acid-moderated spent fuel pool. Desorption has been demonstrated to occur at pH ≤ 3. Cs ions also have been shown to have an affinity for these surfaces although the reversibility of Cs+ bonding by H+ ion exchange has not been fully demonstrated. These results have significant implications for effective decontamination and coating processes used on nuclear fuel transportation casks. 9 refs., 5 figs., 1 tab

  2. Separation of cesium by ion exchange columns

    Crystalline silico titanate (CST) has been tested as a selective inorganic ion exchanger to separate Cs 137 from the residual fission product s solution of the Mo 99 plant. The tests are described in detail and show decontamination factors higher than 6000 and a good elution yield

  3. Thermal Analysis of LANL Ion Exchange Column

    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.

  4. Radiation effects on ion exchange materials

    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

  5. Radiation effects on ion exchange materials

    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.

  6. Ball-like inorganic ion exchangers

    Presented are the results of works aimed at developing the method of obtaining ball-shaped inorganic ion exchangers with suitable exchange and mechanical properties. Satisfactory results have been obtained at using the sol-gel method, which is characterized by its product of spherical particles. The preparation method of hydrooxidic gels of aluminium, chromium, iron, silicon, germanium, titanium, zirconium, tin, niobium, tantalum, thorium and uranium has been mastered. By the gel conversion of hydrooxidic character, low-soluble compounds, possessing ion exchange properties have been prepared. Among them, phosphates, ferrocyanides, sulfides, molybdates, vanadates are of special significance. Cesium capture on zirconium phosphate, possessing interesting properties from the veiwpoint of nuclear technique, has been considered in detail

  7. Immobilisation of ion exchange resins in cement

    Over the last seven years, Low Oxidation State Metal Ion reagents (LOMI) have been used to decontaminate the 100 MW(e) Steam Generating Heavy Water Ractor (SGHWR) at Winfrith. The use of these reagents has resulted in a dilute ionic solution containing activation products which are produced by corrosion of metallic components in the reactor. It has been demonstrated that the amount of activity in the solution can be reduced using organic ion exchanger resins. These resins consist of a cross linked polystyrene with sulphonic acid or quaternary ammonium function groups and can be successfully immobilised in blended cement systems. The formulation which has been developed is produced from a 9 to 1 blend of ground granulated blast furnace slag (BFS) and ordinary Portland cement (OPC) containing 28% ion exchange resin in the water saturated form. If 6% Microsilica is added to the blended cement the waste loading can be increased to 36 w/o. (author)

  8. SpeedUptrademark ion exchange column model

    The Savannah River Site (SRS) is studying non-elutable ion exchange using crystalline silicotitanate (CST) as a potential replacement for the In-Tank Precipitation process to remove Cesium from SRS soluble radioactive waste. A transient model to describe the process of loading Cesium onto the granular fixed bed in an ion exchange (IX) column has been developed using the SpeedUp 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 IX column model was tested by comparison with the analytical solutions of transport problems from the ion exchange literature. In addition, a sample calculation of a train of three CST IX columns was made using both the SpeedUp model and Purdue University's VERSE-LC code. This paper summarizes the model development and verification assessment

  9. Poster 29. Modelling of ion exchange processes in ultrapure water

    The ion exchange process of the Reactor Water Clean-up (RWCU) system has been studied to better use the maximum possible exchange capacity of the ion exchange resin. Laboratory data have been correlated with computer simulations of the ion exchange process. Data were correlated using a mixed-bed ion exchange model for ultralow ionic concentrations developed at Oklahoma State University. Experimental results of the ion exchange column operation in the concentration range of 10-3 M boric acid is compared with the simulated performance predicted by the computer model. The model is found to agree reasonably well with the data. (author)

  10. Porous solid ion exchange wafer for immobilizing biomolecules

    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.

  11. Ion exchange properties of carboxylate bagasse

    Bagasse fibers were chemically modified using three different reactions: esterification using monochloro acetic acid, esterification using succinic anhydride, and oxidation using sodium periodate and sodium chlorite to prepare cation exchanger bearing carboxylic groups. Bagasse was crosslinked using epichlorohydrin before chemical modification to avoid loss of its constituents during the chemical modification. The structure of the prepared derivatives was proved using Fourier transform infrared (FTIR) and chemical methods. The ability of the prepared bagasse cation exchangers to adsorb heavy metal ions (Cu+2, Ni+2, Cr+3, Fe+3), on a separate basis or in a mixture of them, at different metal ion concentration was tested. Thermal stability of the different bagasse derivative was studied using thermogravimetric analysis (TGA)

  12. Electrochemical regeneration of spent ion exchange resin

    CAN-DECON™, CAN-DEREM™ and CAN-DEREM Plus™ processes developed by Atomic Energy of Canada Limited (AECL) are dilute regenerative chemical decontamination processes that employ ion exchange resin to remove dissolved metals and radionuclides and to regenerate the reagents. Depending on the system volume and oxide and radionuclide inventories, a large volume of spent ion exchange resin may be generated. Storage and long term disposal of spent resin may be one of the impediments to routine use of chemical decontamination processes. An electrochemical method is being developed by AECL for the regeneration of spent ion exchange resin generated during application of CAN-DECON, CAN-DEREM and CAN-DEREM Plus processes. In addition, some of the work being carried out is directed at methods for liquid waste treatment. This paper will describe the three-compartment electrochemical cell developed for laboratory tests. The cell consists of an anode, cathode and central compartment, the latter containing either solid spent resin or spent solution. The anode and the cathode compartments are separated from the central section by cation exchange membranes which allow cations to transport from anode to cathode compartments through the membranes. The paper will discuss the results of cyclic voltammetry tests performed in CAN-DEREM reagents to determine the iron redox potential in these electrolytes. The results of iron deposition tests performed in simulated spent CAN-DEREM reagents to study the current efficiency of iron deposition as a function of iron concentration, pH, cathode material and temperature will be presented. The results of tests of several commercial cation exchange membranes to study transport efficiency of iron through these membranes will also be discussed. (author)

  13. Cesium and strontium ion specific exchangers

    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.

  14. Novel silica-based ion exchange resin

    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.

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

    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

  16. Microbial treatment of ion exchange resins

    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)

  17. Microbial treatment of ion exchange resins

    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)

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

    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.

  19. Solidification of ion exchange resin wastes

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

  20. Real Output and Prices Adjustments under Different Exchange Rate Regimes

    Rajmund MIRDALA

    2013-01-01

    Exchange rate regimes evolution in the European transition economies refers to one of the most crucial policy decision in the beginning of the 1990s employed during the initial stages of the transition process. During the period of last two decades we may identify some crucial milestones in the exchange rate regimes evolution in the European transition economies. due to existing diversity in exchange rate arrangements in the European transition economies in the pre-ERM2 period there seems to ...

  1. Biodegradation of ion-exchange media

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

  2. Biodegradation of ion-exchange media

    Ion Exchange resin waste from the high flux beam reactor at Brookhaven National Laboratory provided a mixed microbial culture which was used to evaluate the ability of different resin types to support biological activity. The culture of bacteria and fungi grew after the dewatered resin wastes were mixed with water, nutrient slats and a secondary carbon source. The effects of environment factors such as resin chemicals sorbed on the resins and radiation damage were examined. Heavier growths were seen in Amberlite IRN resins subjected to 100 Mrad of gamma irradiation. The presence of organic acids anions (used in dilute chemical decontamination processes) on the resins encouraged heavier microbial growths

  3. Ion exchange resin for immobilizing radioactive waste

    Snyder, T.S.; Burgman, H.A.; Nahemow, M.D.

    1988-10-25

    A method of making an ion exchange material comprising: (1) implanting a ceramic material with an element selected from the group consisting of sulfur, carbon, phosphorus, nitrogen mixtures thereof; (2) oxidizing the sulfur to sulfate, the carbon to carboxylate or carbonate, the phosphorus to phosphate, the nitrogen to nitrate, or reducing the nitrogen to amine or amide, wherein the element is implanted at an energy of at least about 50 KeV and at a concentration of at least about 10/sup 12/ moieties per cm/sup 2/.

  4. Ion exchange resin for immobilizing radioactive waste

    A method of making an ion exchange material comprising: (1) implanting a ceramic material with an element selected from the group consisting of sulfur, carbon, phosphorus, nitrogen mixtures thereof; (2) oxidizing the sulfur to sulfate, the carbon to carboxylate or carbonate, the phosphorus to phosphate, the nitrogen to nitrate, or reducing the nitrogen to amine or amide, wherein the element is implanted at an energy of at least about 50 KeV and at a concentration of at least about 10/sup 12/ moieties per cm/sup 2/

  5. Ion-exchange selectivities on antimonic acids and metal antimonates

    Antimonic acids and metal antimonates as the inorganic ion-exchangers exhibit extremely high selectivity for a certain element or group of elements for comparison with sulfonated polystyrene ion-exchange resin. Various antimonic acid materials have been obtained with different compositions and ion-exchange properties, depending on the method of their preparations as well as on aging. The species can be divided into three groups - crystalline, amorphous and glassy. The affinity sequence for alkali metal ions shows LiNa>K>Rb>Cs. These selectivities are discussed in the terms of steric effect and entropy changes of the ion-exchange reactions. (author)

  6. Radionuclide Leaching from Organic Ion Exchange Resin

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

  7. The mechanism of ion exchange on ammonium 12-molybdophosphate (AMP)

    This paper reviews some published and unpublished data on the ion-exchange properties of AMP. The three NH4+ ions are only partially exchanged for large monovalent ions. In the case of NH4+/K+ exchange, the energy lost by the breaking of H bonds between the NH4+ ions and anionic cage oxygen atoms beyond the point of maximum exchange is no longer compensated for by bond strengthening in the anion due to contraction of the cage. With Rb+, Cs+ and T1+, limited convertibility results from the lattice expansion required to accommodate these larger ions. During exchange, part of the cations pass through the anionic cages, thereby causing considerable lattice disorder. The maximum exchange capacity of AMP for the alkali metal ions is not a simple function of cation radius. (author)

  8. Synthesis, characterization and ion exchange properties of a new inorganic ion exchange material: zirconium(IV) iodooxalate

    A new three component inorganic ion exchange material zirconium (IV) iodooxalate (ZIO) has been synthesized by adding a mixture of O.1M potassium iodate and O.1M oxalic acid to O.1M zirconium oxychloride in different volume ratios at pH 1. Among several samples synthesized, ZIO-6 is selected for detailed studies owing to its highest ion exchange capacity and chemical stability. The material has been characterized on the basis of chemical composition, pH-titration, FTIR and thermogravimetric studies. The ion exchange capacity of the material for Na+ ion has been found to be 2.70 meq g-l dry exchanger. The ion exchange capacity varies and is found to depend upon the crystal ionic radius of exchanging cations. The chemical stability of the material has been tested in acidic, neutral and basic media. The sorption studies of some metal ions have been made in distilled water and nitric acid. (author)

  9. Effects of ionizing radiation on modern ion exchange materials

    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.

  10. Effects of ionizing radiation on modern ion exchange materials

    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

  11. Method of decomposing radioactive spent ion exchange resins

    Purpose: To improve the decomposability of spent ion exchange resins such as anionic resins, anionic - cationic mixed resins or the likes issued from nuclear power plants. Method: Spent ion exchange resins containing radioactive materials are decomposed by hydrogen peroxide. In this case, anionic exchange resins or mixture of anionic exchange resins and cationic exchange resins are decomposed by using bivalent or trivalent iron ions coexistent with sulfate groups in excess of the amount corresponding to the molar amount of bivalent or trivalent iron ions as a catalyst. Since the anionic exchange resins or the mixture of the anionic exchange resins and cationic resins are decomposed substantially completely, the amount of residue after the decomposition is reduced and the volume-reducing property of the radioactive wastes can be improved to facilitate the solidifying treatment. (Moriyama, K.)

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

    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.

  13. Pyrolysis of Spent Ion Exchange Resins

    Ion exchangers (IEX in international language) are used to remove radionuclides from the primary coolant in all nuclear power stations with a water cooling circuit. This is done by continuously removing a volume of coolant from the primary circuit and passing it through coolers, filters and the ion exchange beds. Cation and anion exchangers, in the form of coarse-grained resin beads in pressurized-water reactors and as finely ground powdered resins in boiling water reactors, are used. The trend for new power stations is to exploit all the possibilities for avoiding the generation of contaminated liquids and then to clean, as far as possible, the solutions that are nevertheless generated using ion exchange for it to be possible to dispose of them as non-radioactive waste. This relieves the burden on evaporator facilities, or means that these can even be dispensed with entirely. Regeneration is possible in principle, but little use is made of it. As the regeneration usual in conventional technologies is not employed in nuclear power stations, it is necessary to dispose of this material as radioactive waste. On the international level, a great number of processes are offered that are intended to meet the relevant national regulations, and these will be discussed in brief with their advantages and disadvantages. The aim is then to find a process which reduces the volume, yields an inert or mineralized product, works at temperatures of no more than approximately 600 deg. C and can be run in a simple facility. Originally, the pyrolysis process was developed to treat liquid organic waste from reprocessing. A typical application is the decomposition of spent solvent (TBP, tributyl phosphate, mixed with kerosene). In this process TBP is pyrolyzed together with calcium hydroxide in a fluidized bed facility at temperatures of around 500 deg. C, the calcium hydroxide reacts with the phosphate groups directly to form calcium pyrophosphate which contains all the radioactivity

  14. The effect of organic ion-exchange resin on properties of heterogeneous ion-exchange membranes

    Křivčík, J.; Vladařová, J.; Hadrava, J.; Černín, A.; Brožová, Libuše

    2010-01-01

    Roč. 14, - (2010), s. 179-184. ISSN 1944-3994. [Membrane Science and Technology Conference of Visegrad Countries /4./ PERMEA 2009, 07.07.2009-11.07.2009] R&D Projects: GA MPO FT-TA4/116 Institutional research plan: CEZ:AV0Z40500505 Keywords : heterogeneous ion-exchange membrane * membrane modification * particle size of distribution Subject RIV: CG - Electrochemistry Impact factor: 0.752, year: 2010

  15. Synthesis, Characterization and Ion Exchange Properties of Lithium Zirconium Silicate as Inorganic Ion Exchanger

    A new three components inorganic ion exchange material lithium zirconium silicate (Li Zr Si) has been synthesized by adding a mixture of lithium hydroxide (LiOH)and zirconium oxychloride (ZrOCI2) to sodium metasilicate (Na2Si O3) in different volume ratios. the synthesized materials ratios I,II and III have been characterize on the basis of chemical composition, X-ray fluorescence, X-ray diffraction, fourier transform infrared spectroscopy (FTIR) and thermal analysis . from the data obtained the synthesized different ratios of lithium zirconium silicates can be written as (Zr O)2 Li2 (SiO3)3. 10.7H2O, (Zr O) Li2(SiO3)2-5.3H2O and (Zr o)Li4 (SiO3)3- 4.4 H2O with amorphous structure. The chemical stability of the materials has been tested in water and acidic media. The ion exchange capacities of these materials for Na+, K+and Cs+ ions have been found to take the order Na+>K+>Cs+for all synthesized materials and depend on the crystal ionic radii of exchanging cations

  16. Synthesis, Characterization and Ion Exchange Properties of Lithium Zirconium Silicate as Inorganic Ion Exchanger

    A new three components inorganic ion exchange material lithium zirconium silicate (LiZrSi) has been synthesized by adding a mixture of lithium hydroxide (LiOH) and zirconium oxychloride(ZrOCl2) to sodium metasilicate (Na2SiO3) at different ratios. The synthesized materials ratios I, II and III have been characterized on the basis of chemical composition, X-ray fluorescence, XRD, Fourier Transform Infrared Spectroscopy (FTIR) and thermal analysis. From the data obtained, the synthesized different ratios of lithium zirconium silicates can be written as (ZrO)2Li2(SiO3)3. 10.7H2O, (ZrO)Li2(SiO3)2. 5.3H2O and (ZrO)Li4(SiO3.3. 4.4H2O with amorphous structure. The solubility of the materials has been tested in water and acidic media. The ion exchange capacities of these materials for Na+, K+ and Cs+ ions have been found to take the order Na+ > K+ > Cs+ for all synthesized materials and depend on the ionic radii of exchanging cations

  17. Treatment of Soil Decontamination Solution by the Cs+ Ion Selective Ion Exchange Resin

    Occasionally, radioactively contaminated soils have been excavated and stored at the temporary storage facility. Cesium as a radionuclide is one of the most toxic elements and it has a long half decay life. During the operation of nuclear facility, soils near the facility would be contaminated with radioactive cesium and it will cause the deleterious effect to human body and environment. In this study, Cs+ ion selective ion exchange resin was prepared by changing the functional group of commercial anion exchange resin for a ferrocyanide ion. Ion exchange capability of using the soil decontamination solution was investigated. We also performed the feasibility test of recycling the spent Cs ion selective ion exchange resin

  18. Development of heat resistant ion exchange resin. First Report

    In nuclear power stations, as a means of maintaining the soundness of nuclear reactors, the cleaning of reactor cooling water has been carried out. But as for the ion exchange resin which is used as the cleaning agent in the filtrating and desalting facility in reactor water cleaning system, since the heat resistance is low, high temperature reactor water is cooled once and cleaned, therefore large heat loss occurs. If the cleaning can be done at higher temperature, the reduction of heat loss and compact cleaning facilities become possible. In this study, a new ion exchange resin having superior heat resistance has been developed, and the results of the test of evaluating the performance of the developed ion exchange resin are reported. The heat loss in reactor water cleaning system, the heat deterioration of conventional ion exchange resin, and the development of the anion exchange resin of alkyl spacer type are described. The outline of the performance evaluation test, the experimental method, and the results of the heat resistance, ion exchange characteristics and so on of C4 resin are reported. The with standable temperature of the developed anion exchange resin was estimated as 80 - 90degC. The ion exchange performance at 95degC of this resin did not change from that at low temperature in chloride ions and silica, and was equivalent to that of existing anion exchange resin. (K.I.)

  19. Silver(I) sorption on zirconium phosphate ion exchangers

    This article is devoted to silver sorption on zirconium phosphate ion exchangers. Thus, the sorption of silver from nitrate and ammoniac solutions on three component ion exchangers is studied. Influence of ph on sorption of zirconium phosphates is studied as well.

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

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

  1. New System for Dynamic Ion Exchange in Countercurrent

    This system was developed according to a new assumption which supposed that ion-exchange operation can be done by mechanical agitation in separate batches, followed by transferring the partially loaded resin to contact with a fresh liquor and transferring the partially depleted liquor to contact with a fresh resin to make countercurrent action. By this way, tbe maximum expected facilities in ion exchange technique could be successfully employed. It comprises rapid contacting through mechanical agitation to accelerate ion exchange reaction and consequently enhance the reaction kinetic. This was followed by moving both of resin and leach liquor in opposite directions to perform countercurrent action. This led to both highly reducing in processing time, and effective use of the resin capacity. It is also constructed to complete the purposed advantages in the previous ion exchange systems and creation of new parameters for ion exchange process.

  2. Ion exchange behaviour of polymeric zirconium cations

    Polymeric zirconium cations formed in weakly acid solutions (pH2) are taken up strongly into macroporous cation exchange resins, while uptake into normal cation exchange resins (pore diameter about 1 nm) is low. Macroporous cation exchange resins loaded with polymeric Zr cations are shown to function as ligand exchange sorbents. (Authors)

  3. Studies on separation of boron isotopes by ion exchange

    Studies have been carried out for the enrichment of boron isotopes by the ion exchange method using various anion exchange resins available. The elementary separation factors and heights equivalent of theoretical plate were measured at different concentrations and flow rates. A number of experiments were performed to study the displacement of borate band on ion exchange columns. The problem of CO2 evolution during displacement was also studied and a solution was found. (author). 9 refs

  4. Ion exchange separation for decontamination of centrifuge enrichment plant

    Ion exchange separation of uranyl ion (UO22+) from metal cations has been carried out by the columnar operation using ion exchange resins in 0.1 mol/dm3 sulfuric acid medium. Uranyl ion was adsorbed in an anion exchange resin and the rest metal cations, Fe(III), Al(III), Cr(III), Ni(II) and Cu(II) ions, were adsorbed in a cation exchange resin in this system. Desorption of uranyl ion and metal cations adsorbed in the resins were tested by 2 mol/dm3 sulfuric acid solution. Desorbed elements were confirmed to be precipitated by appropriate alkaline solutions. On the basis of the results obtained, a concept was made on a decontamination system for uranium-contaminated waste solution from centrifuge enrichment plant. (author)

  5. Study on actinoid isolation by antimonide ion exchanger

    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.)

  6. Ion exchange defines the biological activity of titanate nanotubes.

    Rónavári, Andrea; Kovács, Dávid; Vágvölgyi, Csaba; Kónya, Zoltán; Kiricsi, Mónika; Pfeiffer, Ilona

    2016-05-01

    One-dimensional titanate nanotubes (TiONTs) were subjected to systematic ion exchange to determine the impact of these modifications on biological activities. Ion exchanged TiONTs (with Ag, Mg, Bi, Sb, Ca, K, Sr, Fe, and Cu ions) were successfully synthesized and the presence of the substituted ions was verified by energy dispersive X-ray spectroscopy (EDS). A complex screening was carried out to reveal differences in toxicity to human cells, as well as in antibacterial, antifungal, and antiviral activities between the various modified nanotubes. Our results demonstrated that Ag ion exchanged TiONTs exerted potent antibacterial and antifungal effects against all examined microbial species but were ineffective on viruses. Surprisingly, the antibacterial activity of Cu/TiONTs was restricted to Micrococcus luteus. Most ion exchanged TiONTs did not show antimicrobial activity against the tested bacterial and fungal species. Incorporation of various ions into nanotube architectures lead to mild, moderate, or even to a massive loss of human cell viability; therefore, this type of biological effect exerted by TiONTs can be greatly modulated by ion exchange. These findings further emphasize the contribution of ion exchange in determining not only the physical and chemical characteristics but also the bioactivity of TiONT against different types of living cells. PMID:26972521

  7. Inorganic ion exchange evaluation and design: Silicotitanate ion exchange waste conversion

    Ion exchange materials are being evaluated for removing Cs, SR from tank waste. Thermal conversion of a variety of compositions within the Cs2O-TiO2-SiO2 phase diagram yielded both glass and crystalline materials, some of which show low leach rates and negligible Cs losses during heat treatment. A new material, CsTiSi206, with a structure isomorphous to pollucite (CsAlSi206) has been identified. This material represents a new class of crystalline zeolite materials which contain large amounts of titanium. Direct conversion of Cs loaded silicotitanate ion exchangers to CsTiSi2O6 is an excellent alternative to dissolving the Cs-loaded or Cs-eluted exchangers in borosilicate glass because: CsTiSi2O6 is formed using a simple, one step heat treatment. The unique crystalline pollucite-like structure of CsTiSi2O6 traps Cs, and exhibits extremely low Cs leach rates. CsTiSi2O6 is converted to solid waste at a low processing temperature of 700 to 800 C (nominal melter operating temperatures are 1150 C). CsTiSi206 concentrates the waste, thus generating lower volumes of expensive HLW. Cs losses due to volatilization during processing of CsTiSi2O6 are extremely low

  8. Cation exchange abilities of nanocomposites based on ion exchange resin and zirconium hydrophosphate

    A modification of cation-exchange resin with nanoparticles of zirconium hydrophosphate leads to the synergism of ion-exchange properties. The exchange of Cu2+→H+ shows that the nanocomposite ion exchangers demonstrate a high affinity to d-metal ions due to the polymer matrix, as well as to the inorganic component. The best characteristics are obtained for materials containing spherical particles of zirconium hydrophosphate with a diameter of (1.4-1.7) x 10-8 m, these aggregates being the most porous.

  9. Study of kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 5

    The kinetics of Na+ - UO22+ and Mg2+ - UO22+ ion exchange on strongly acidic cation exchangers in a batch stirred reactor was studied. The exchangers Ostion KS (containing DVB in the range of 1.5-12%) and Amberlite IR 120 for experimental work were used; the concentration of the aqueous nitrate solution was always 0.2 molx1-1. The Nernst-Planck equation was applied for description of ion diffusion in the particle. The diffusion coefficients of UO22+ ions in the exchangers and their dependence on the content of DVB were obtained by evaluating the experimental data. (author)

  10. Study of kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 4

    The kinetics of ion exchange in the Nasup(+)-Mgsup(2+)-strongly acidic cation exchanger system in a batch stirred reactor was studied. The samples of exchangers OSTION KS (containing DVB in the range of 1.5 - 12%) and AMBERLITE IR 120 for experimental work were used; the concentration of the aqueous nitrate solution was always 0.2M. The Nernst-Planck equation for description of diffusion of ions in a particle was used. The values of diffusion coefficients of magnesium ions in the exchangers and their dependence on the content of DVB were obtained by evaluating the experimental data and using the self-diffusion coefficients of sodium. (author)

  11. Ion exchange nonwoven fabric chemical filter. 2

    This report outlined the characteristics of EPIX filter and its complex with activated carbon to eliminate organic compounds from solvent. Elimination performance of this filter was determined using an ion chromatographic analyzer. EPIX filter showed high performance to eliminate trace amount of ionic compounds. The rate of elimination was both 99% or more for NH3 and SO2 in an early phase of filtration. Release of dust as well as impurities was significantly reduced by the use of EPIX filter. Gases once adsorbed on the filter were not released even at an elevated temperature of atmosphere. Combined use of non-woven fabrics was possible. For EPIX filter, there are three kinds; strong acid cation exchange filter and strong/weak basic anion filters. The weak basic anion filter has been applied to the conventional apparatus in wafer makers because the filter was very effective for selective boron trapping. When polyethyleneterephthalate was used as the base polymer, radical groups produced on the polymer were co-polymerized with monomer substances. The lifetime of filter was estimated on a base of gas concentration and wind velocity to determine the time to replace with a new one. Furthermore, the loss of pressure became less than a half when EPIX filter was used. (M.N.)

  12. Pyrolysis of spent ion-exchanger resins

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

    2012-11-01

    Initial tests have shown that ion exchangers (IEX) can be decomposed by pyrolysis with very good results, yielding an inert and chemically resistant product. No additives are necessary. The main constituent of the product, the pyrolysis residues or ash, is carbon. It has been discovered that the entire radioactive inventory remains in the pyrolysis residues during pyrolysis of the IEX. This is achieved by relatively low process temperatures that prevent highly volatile nuclides such as the caesium nuclides from passing into the gaseous phase. Sintered metal filters in pyrolysis plant ensure that even the radioactivity bonded to the dust remains in the pyrolysis residues. In addition to the radionuclides, the main constituents of the residue are carbon from the original polystyrene matrix and sulphur from the functional groups. The pyrolysis residues form a flowable solid material and not a melt. It is thus easy to handle and can be compacted or cemented, depending on the requirements for interim and permanent storage. Any further constituents such as inorganic filter materials or even other organic materials do not interfere with the process, they are dried, calcined or also pyrolysed. (orig.)

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

    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.

  14. Preparation of Nafion 117™-SnO2 Composite Membranes using an Ion-Exchange Method

    Nørgaard, Casper Frydendal; Nielsen, Ulla Gro; Skou, Eivind Morten

    Nafion 117™-SnO2 composite membranes were successfully prepared using an ion-exchange method. SnO2 was incorporated into Nafion 117™ membranes by ion-exchange in solutions of SnCl2 · 2 H2O in methanol, followed by oxidation to SnO2 in air. The content of SnO2 proved controllable by adjusting the ...

  15. Gadolinium-hydrogen ion exchange of zirconium phosphate

    Liu, D. C.; Power, J. L.

    1972-01-01

    The Gd(+3)/H(+) ion exchange on a commercial zirconium phosphate ion exchanger was investigated in chloride, sulfate, and phosphate solutions of Gd(+3) at gadolinium concentrations of 0.001 to 1 millimole per cc and in the pH range of 0 to 3.5. Relatively low Gd(+3) capacities, in the range of 0.01 to 0.1 millimole per g of ion exchanger were found at room temperature. A significant difference in Gd(+3) sorption was observed, depending on whether the ion exchanger was converted from initial conditions of greater or lesser Gd(+3) sorption than the specific final conditions. Correlations were found between decrease in Gd(+3) capacity and loss of exchanger phosphate groups due to hydrolysis during washing and between increase in capacity and treatment with H3PO4. Fitting of the experimental data to ideal ion exchange equilibrium expressions indicated that each Gd(+3) ion is sorbed on only one site of the ion exchanger. The selectivity quotient was determined to be 2.5 + or - 0.4 at room temperature on gadolinium desorption in chloride solutions.

  16. Separation of zirconium from hafnium by ion exchange

    Zirconium and hafnium are two of the most important metals for the nuclear industry. Hafnium occurs in all zirconium ores usually in the range 2 - 3%. However, for the most nuclear industry applications, it is necessary to use a zirconium of extremely pure level. The current work consists in the separation of zirconium and hafnium by the ion exchange method in order to obtain a zirconium concentrate of high purity. The zirconium and hafnium liquors were produced from the leaching of the Zr(OH)4 and Hf(OH)4 with nitric acid for 24 hours. From these two liquors it was prepared one solution containing 7.5 x 10-2 mol L-1 of Zr and 5.8 x 10-3 mol L-1 of Hf with acidity of 1 M. Ion exchange experiments were carried out in batch with the resins Dowex 50WX4, Dowex 50WX8 100, Dowex 50WX8 50, Amberlite IR-120 and Marathon C at constant temperature 28 deg C. Other variables such as, acidity and agitation were kept constant. The data were adjusted to Langmuir equation in order to calculate the maximum loading capacity (qmax) of the resins, the distribution coefficient (Kd) for Zr and Hf and the separation factor (αHfZr ). The results of maximum loading capacity (qmax) for Zr and Hf, in mmol g-1, showed that the most suitable resins for columns experiments are: Dowex 50WX4 50 (qmax Zr = 2.21, Hf = 0.18), Dowex 50WX8 50 (qmax Zr = 1.89, Hf = 0.13) and Amberlite (qmax Zr = 1.64, Hf = 0.12). However, separations factors, αHfZr, showed that the resins are not selective. (author)

  17. Separation of zirconium from hafnium by ion exchange

    Felipe, Elaine C.B.; Palhares, Hugo G.; Ladeira, Ana Claudia Q., E-mail: elainecfelipe@yahoo.com.br, E-mail: hugopalhares@gmail.com, E-mail: ana.ladeira@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-07-01

    Zirconium and hafnium are two of the most important metals for the nuclear industry. Hafnium occurs in all zirconium ores usually in the range 2 - 3%. However, for the most nuclear industry applications, it is necessary to use a zirconium of extremely pure level. The current work consists in the separation of zirconium and hafnium by the ion exchange method in order to obtain a zirconium concentrate of high purity. The zirconium and hafnium liquors were produced from the leaching of the Zr(OH){sub 4} and Hf(OH){sub 4} with nitric acid for 24 hours. From these two liquors it was prepared one solution containing 7.5 x 10{sup -2} mol L{sup -1} of Zr and 5.8 x 10{sup -3} mol L{sup -1} of Hf with acidity of 1 M. Ion exchange experiments were carried out in batch with the resins Dowex 50WX4, Dowex 50WX8 100, Dowex 50WX8 50, Amberlite IR-120 and Marathon C at constant temperature 28 deg C. Other variables such as, acidity and agitation were kept constant. The data were adjusted to Langmuir equation in order to calculate the maximum loading capacity (q{sub max}) of the resins, the distribution coefficient (K{sub d}) for Zr and Hf and the separation factor (α{sub Hf}{sup Zr} ). The results of maximum loading capacity (q{sub max}) for Zr and Hf, in mmol g{sup -}1, showed that the most suitable resins for columns experiments are: Dowex 50WX4 50 (q{sub max} Z{sub r} = 2.21, Hf = 0.18), Dowex 50WX8 50 (q{sub max} Zr = 1.89, Hf = 0.13) and Amberlite (q{sub max} Zr = 1.64, Hf = 0.12). However, separations factors, α{sub Hf}{sup Zr}, showed that the resins are not selective. (author)

  18. The decontamination of spent regenerant by ion exchange and filtration

    The sodium sulfate solutions produced by the regeneration of deep bed polisher resins have typically been prepared for disposal by concentration by evaporation followed by solidification in concrete. Filtration and ion exchange followed by discharge of the sodium sulfate solution is one possible alternative to evaporation and solidification. The high salt content of the solutions makes the use of non-selective ion exchange resins volume inefficient. This paper describes tests using filtration and selective ion exchange to clean regenerative wastes. It concludes that such a process is technically feasible and would result in substantial cost savings and volume reduction

  19. Tc-99 Ion Exchange Resin Testing

    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.

  20. The exchange rate as an adjustment mechanism: a structural VAR approach to the case of Ireland

    Dermot Hodson

    2003-01-01

    Ireland’s participation in stage three of Economic and Monetary Union precludes exchange rate adjustment in response to asymmetric shocks. A Structural VAR model is used to decompose the effects of asymmetric supply, demand and nominal disturbances on macroeconomic imbalances between Ireland and the UK and on the Irish pound-sterling exchange rate. The results indicate that supply shocks account for a significant degree of the fluctuation in both variables. This lends weight to the view that ...

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

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

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

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

    2010-09-01

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

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

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

  4. Ion Exchange Separation of the Oxidation State of Vanadium.

    Cornelius, Richard

    1980-01-01

    Describes an experiment that emphasizes the discrete nature of the different oxidation states of vanadium by the separation of ammonium metavanadate into all four species by ion exchange chromatography. (CS)

  5. Inorganic ion exchangers. Application to liquid effluent processing

    Main inorganic ion exchangers used for radioactive liquid effluents presented in this report are: synthetic and natural zeolites, in titanium oxides, titanates, niobates, tantalates, zirconates, some insoluble salts of zirconium, molybdenum and tin, heteropolyacids and polyantimonic acid. Properties of these ion exchangers are described: structure, adsoption, radiation effects and thermal stability, application to waste processing, radioactive waste storage uranium and cesium 137 recovery are evoked

  6. Nonlinear Adjustment, Purchasing Power Parity and the Role of Nominal Exchange Rates and Prices

    Beckmann, Joscha

    2011-01-01

    Although the literature on purchasing power parity (PPP) is rich in controversy, the relative contribution of prices and nominal exchange rates to real exchange rate movements which restore PPP disequilibria has rarely been put under any close scrutiny. Using monthly data from 1973:01 to 2009:12 from the USA, UK, Germany, France and Japan, this paper as a fi rst step applies a cointegrated VAR framework to test for stationary real exchange rates and linear adjustments in prices and nominal ex...

  7. Sorption selectivity of alkali metal ions in polymer inclusion ion exchange membranes

    Sorption selectivity of different alkali metal ions in polymer inclusion cation exchange membranes has been studied. The concentration of the metal ions were measured using neutron activation analysis. The results show the selectivity of polymer inclusion membranes for metal ions in the order Na++++. The trend have been explained in terms of the radius of the hydrated metal ion. (author)

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

    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.

  9. Thermochemical treatment of spent ion exchange resins

    Spent ion exchange resins (IER) is a principal type of radioactive waste constantly generated by nuclear plants of various functions. The reduction of volume of this waste and its treatment to the forms suitable for long-term disposal is an urgent problem facing the present-day atomic energetics. Nowadays the technological process THOR (Studsvik, Sweden) based on the thermodestruction of IER is the best developed and realized on the industrial scale. Unfortunately, this process requires expensive equipment and great energy consumption for the moisture to be evaporated and thereafter IER to be destroyed by heat. Meanwhile the capability of some elements (Mg, Al, Si, Ti etc.) has long been known and practical use found for active interaction with water in combustion regime. This property of the metals has been used in the development of new technology of treatment of IERs in SIA ''Radon''. Wet IER is mixed with powder metal fuel (PMF) which represents a mixture of metal powder, a quantity of burning activator and some technological additives. On initiation, the mixture of IER with PMF burns without extra energy supply to generate enough heat for the moisture to be evaporated and products of IER decomposition to be destroyed and evaporated. To burn out the products of IER evaporation the air is used. The thermodynamic simulation data and the results of experiments using a pilot plant show that radionuclides contained in IER are chemically bound in ash residue consisting of metal oxides, spinel, silicates, etc. According to the experimental data, radionuclides in amounts of 90% or more of Cs-137 and up to 95% of Sr-90 and Co-60 are fixed in the ash residue. The residue volume is several times less than the initial volume of IER. Concentrations of hazard gases in off-gases do not exceed maximum permissible ones accepted in different countries. The technological process is easy to perform, it does not require sophisticated equipment and great energy consumption which

  10. Advanced ion exchange resins for PWR condensate polishing

    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)

  11. Ion momentum and energy transfer rates for charge exchange collisions

    Horwitz, J.; Banks, P. M.

    1973-01-01

    The rates of momentum and energy transfer have been obtained for charge exchange collisions between ion and neutral gases having arbitrary Maxwellian temperatures and bulk transport velocities. The results are directly applicable to the F-region of the ionosphere where 0+ - 0 charge is the dominant mechanism affecting ion momentum and energy transfer.

  12. A zeolite ion exchange membrane for redox flow batteries.

    Xu, Zhi; Michos, Ioannis; Wang, Xuerui; Yang, Ruidong; Gu, Xuehong; Dong, Junhang

    2014-03-01

    The zeolite-T membrane was discovered to have high proton permselectivity against vanadium ions and exhibit low electrical resistance in acidic electrolyte solutions because of its enormous proton concentration and small thickness. The zeolite membrane was demonstrated to be an efficient ion exchange membrane in vanadium redox flow batteries. PMID:24396857

  13. Modeling multicomponent ion exchange equilibrium utilizing hydrous crystalline silicotitanates by a multiple interactive ion exchange site model

    An equilibrium multicomponent ion exchange model is presented for the ion exchange of group I metals by TAM-5, a hydrous crystalline silicotitanate. On the basis of the data from ion exchange and structure studies, the solid phase is represented as Na3X instead of the usual form of NaX. By using this solid phase representation, the solid can be considered as an ideal phase. A set of model ion exchange reactions is proposed for ion exchange between H+, Na+, K+, Rb+, and Cs+. The equilibrium constants for these reactions were estimated from experiments with simple ion exchange systems. Bromley's model for activity coefficients of electrolytic solutions was used to account for liquid phase nonideality. Bromley's model parameters for CsOH at high ionic strength and for NO2- and Al(OH)4- were estimated in order to apply the model for complex waste simulants. The equilibrium compositions and distribution coefficients of counterions were calculated for complex simulants typical of DOE wastes by solving the equilibrium equations for the model reactions and material balance equations. The predictions match the experimental results within 10% for all of these solutions

  14. Radiation effects on a zeolite ion exchanger and a pollucite

    Cation exchange capacity and selective Cs and Sr ion sorption measurements were found to be too insensitive to detect radiation effects on irradiated Ionsiv-IE-95 zeolite. However, leaching the zeolite while under γ-irradiation caused a modest increase in the desorption of exchangeable ions. Gamma-irradiation and subsequent leaching of a natural pollucite also slightly enhanced the leachability of this material. The increased desorption of ions from the zeolite and the enhanced leachability of the pollucite are apparently caused by a decrease in pH due to the generation of acidic species during irradiation

  15. Preparation, properties and ion-exchange behavior of stannic silicomolybdate

    The ion-exchange properties of stannic silicomolybdate were studied using the batch method. Preparation of stannic silicomolybdate is shown. The sorbent is stable in water and diluted mineral acids. X-ray diffraction study shows amorphous structure and chemical analysis was performed. The ion-exchange capacities for alkali metals and strontium cations were determined by using fotometric measurements and chemical analyses of the equilibrated exchangers by atomic absorption. The tow techniques showed similar results which revealed that the capacities was changed in values and orders with the changing of the preparation method of the exchangers. The exchangers showed high selectivity for cesium and strontium cations. The results showed decreasing of Kd with increasing of the concentration of ion-exchanger. Also the effect of nitrate anions was investigated by studying the distribution coefficients in nitrate media. The results showed that nitrate anion from nitric acid or ammonium nitrate, led to decrease the distribution coefficients. The results obtained reveal that the properties of the exchangers is slightly changed with the change of the conditions of preparation but the general behaviour of Cs+ and Sr++ cations almost remain the same. Also nitrate solution can be used to reextract these cations from the exchangers. 4 tabs

  16. Nuclear plant applications of selective ion exchange media

    The organic ion exchange resins typically used in PWR reactor waste water cleanup are non ion-selective: i.e., they remove all ionic species present. Most of their ion exchange capacity is taken up by such species as sodium (Na+) and chloride (Cl-) which can be safely returned to the environment. Durasil ion exchange media are designed to selectively remove radioactive species such as cesium (Cs+), cobalt (Co+2) and iodine (I-) typically found in radwaste streams. The application of these media in three PWRs is described. The nature of the waste water in these plants varied from very high to very low conductivity, but the results in all three applications were substantially improved throughputs and superior removal of radioactive species

  17. Study on the permselectivity of ion exchange membrane

    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.

  18. Intraday Speed of Adjustment and the Realized Variance in the Indonesia Stock Exchange

    Zaafri A Husodo

    2009-01-01

    Full Text Available We examine the intraday trading and price dynamics for frequently traded stocks at the Indonesian Stock Exchange. Using trade price, time series generated at one, two, three, five, ten, fifteen, thirty and sixty-minute intervals, we estimate the speed of adjustment and the corresponding realized variance of these series. The objective of the estimation is to infer the noise impact to the deviation of observed prices from their fundamental value. The result from the speed of adjustment estimate is consistent with the realized variance estimator. Both conclude that the 50 most frequently traded stocks in the Indonesia Stock Exchange adjust to new information within 30 minutes. At the interval, the coefficient of the speed of price adjustment is insignificantly different from zero implying negligible noise impact to the observed price. Concurrently, the realized variance starts to stabilize at 30-minute interval purporting fading impact of noise to the realized variance estimate. The evidence justifies the use of realized variance at various intervals as a reliable indicator of price discovery rate in the Indonesia Stock Exchange.

  19. Characterization of electroactive Cs ion-exchange materials using XAS

    Various ion exchange materials have been proposed for the removal of Cs from high level waste streams produced during the reprocessing of fuel rods. Cs can be released from loaded traditional exchange resins by elution and then the resin can be reused. However large quantities of secondary wastes are generated. Another class of single use exchangers is directly incorporated in the loaded state into a solid waste form (e.g., borosilicate glass logs). A third alternative is electroactive ion-exchange materials, where the uptake and elution of Cs are controlled by an applied potential. This approach has several advantages over traditional reusable ion-exchange resin including much reduced secondary waste, higher Cs selectivity, and higher durability. XAS experiments were conducted at the Fe K-edge and Cs LIII-edge on a series of electrochemically produced nickel ferrocyanide films to determine the effects of deposition conditions and subsequent alkali exchange on structural and chemical aspects of the films. The deposition conditions include methods described in the literature and PNNL proprietary procedures. Although the performance and the durability of the films do vary with processing conditions, Fe K-edge EXAFS results indicate that all deposition conditions result in the formation of the cubic phase. Initial results from Cs LIII-edge EXAFS analysis suggest that the Cs ion is present as a hydrated species

  20. THERMODYNAMICS OF ION-EXCHANGED NATURAL CLINOPTILOLITE

    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...

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

    A new class of inorganic ion exchangers called crystalline silicotitanates (CST), invented by researchers at Sandia National Laboratories and Texas A ampersand 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+. 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 ampersand M team consists of submicron-size particles. It is not designed for column ion exchange but may be used in other applications

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

    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.

  3. Inhibition of spent ion exchangers in geopolymer matrix

    Experience with spent ion exchanger mixtures containing 50 % of water encapsulated in geopolymer matrix prepared from natural kaolinitic clay and standard alkali activation is described, with focus on the inhibition of radioactive caesium. Inhibition directly in the inorganic network of the geopolymer was proved. As has been shown previously, the geopolymer reaction could be started by appropriate addition of Na+, K+ or also of Cs+ in aqueous solutions. Metals of group I equilibrate the formatted inorganic network of siloxo-sial chains, resulting in a non-soluble solid matter. The liquid content captured inside the spent ion exchangers contains radioactive material, of which Cs is among the most hazardous. During the experiments, we faced the problem of porosity of the geopolymer matrix, bringing about destruction of samples prepared with more than 10 wt. % dry spent ion exchangers. During the setting of the geopolymer matrix, water as a precursor of the reaction evaporates slowly, leaving small pores of generally 20 μm. Unfortunately, after submerging the sample in water, the penetrating water attacks the dried spherical ion exchanger particles, which groove and damage the sample particles with cracks, followed by total disintegration. This was a reason why we tested a procedure where the wet balls are smashed by using a friction machine and the crushed ion exchanger particles are fixed into the prepared geopolymer matrix in proportions of 14.8 - 17 and 22 wt. %, respectively. The experiments gave favourable results: no destruction after submerging the samples in water was detected. (author)

  4. Phosphorus-contained polycondensation type ion-exchange resins

    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.

  5. Synthetic inorganic ion exchangers. XVI. Electrochromatographic separations of metal ions on zirconium tungstate-impregnated paper

    The electrochromatographic behavior of 25 metal ions on zirconium tungstate-impregnated papers is described. Six background electrolytes were used. On the basis of the differential mobilities of metal ions which depend on the ion-exchange properties of zirconium tungstate and the nature of complex formation with the electrolytes, some important binary and ternary separations have been achieved

  6. MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS

    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.

  7. Catalysis using hydrous metal oxide ion exchangers

    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.

  8. Catalysis using hydrous metal oxide ion exchanges

    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.

  9. Recovery of boric acid from ion exchangers

    The recovery of boric acid from an anion exchange resin is improved by eluting the boric acid with an aqueous solution of ammonium bicarbonate. The boric acid can be readily purified and concentrated by distilling off the water and ammonium bicarbonate. This process is especially useful for the recovery of boric acid containing a high percentage of 10B which may be found in some nuclear reactor coolant solutions. 10 claims

  10. Evaluation of electrochemical ion exchange for cesium elution

    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

  11. Method and device of processing spent ion exchange resins

    Purpose: To formulate the residues of thermally decomposed spent ion exchange resins into firm pellets of excellent durability neither with particular high temperature heat treatment nor by the addition of binders. Method: Spent ion exchange resins are thermally or oxidatively decomposed in an inert atmosphere or oxygen-containing atmosphere at a temperature from 300 to 600 deg C and the decomposition residues obtained thereby are hot pressed at a predetermined temperature into pellets, since firm pellets excellent in durability can be prepared from thermally decomposed or oxidatively decomposed residues of spent ion exchange resins neither with particular high temperature heat treatment nor with addition of binders, it is possible to reduce the cost and simplify the system. (Yoshihara, H.)

  12. Q-CEP trademark processing of spent ion exchange resins

    This paper discusses a commercial process being marketed by Molten Metal Technology (MMT) and Scientific Ecology Group (SEG), aimed at the processing of spent ion exchange resins, to accomplish a volume reduction of a factor of 30, and produce a final state product which is self shielding, stable, and non-exchangeable. The author discusses the facility construction, performance testing, and cost savings based on current and projected disposal costs

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

    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.

  14. Treatment of radioactive wastewaters by chemical precipitation and ion exchange

    Precipitation and ion exchange methods are being developed at Oak Ridge National Laboratory to decontaminate wastewaters containing small amounts of 90Sr and 137Cs while minimizing waste generation. Distribution coefficients have been determined for strontium and cesium as functions of Ca, Na, and Mg concentrations from bench- and pilot-scale data for ion exchange resins and zeolites using actual wastewaters. Models have been used to estimate the total amount of waste that would be generated at full-scale operation. Based on these data, four process flowsheets are being tested at full-scale. 14 refs., 8 figs., 7 tabs

  15. STIRRED FLUIDIZED-BED DRYER OF REGENERATED ION EXCHANGER PARTICLES

    Michal Pěnička

    2014-06-01

    Full Text Available This article describes intensification of the fluidized-bed drying process for regenerated spherical-shape ion exchanger particles in the batch mode, achieved by a mechanical stirrer in the fluidized bed layer of the dried particles. The effect of the mechanical stirring system on the drying process was examined. Calculations as well as results of comparison measurements provide evidence of a favourable effect of stirring on the total drying time as compared to the initial unstirred system. The regenerated ion exchanger particles pass to the fluid state in a shorter time and the ultimate total drying time is thus more than 60% shorter.

  16. Rupture loop annex ion exchange RLAIX vault deactivation

    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.

  17. An investigation on important factors influencing on forecasted earnings adjustment: Evidence from Tehran Stock Exchange

    Fatemeh Babakhani

    2014-01-01

    Full Text Available This paper presents an empirical investigation to detect important factors influencing earning adjustment on firms selected on Tehran Stock Exchange over the period 2006-2011. There are four independent variables associated with the proposed study of this paper including Proportion of shares owned by institutional investors, Return on assets, Profit change and Market value to book value. In addition, Investment restructuring is considered as control variable. The results of the implementation of regression analysis indicate that there was a reverse relationship between earning forecasted adjustment and two independent variables including size of firm as well as the ratio of market value to book value. However, Net profit has a direct and positive relationship with earning forecast adjustment.

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

    Larsen, Erik Huusfeldt; Hansen, Sven Hedegaard

    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 ion...

  19. Waste separation and pretreatment using crystalline silicotitanate ion exchangers

    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.

  20. Thermodynamics of ion exchange on ammonium 12-molybdophosphate

    Standard free energies, enthalpies and entropies for the exchange of NH4+ ions on AMP are reported for eight cationic species. For those ions which are weakly adsorbed (e.g. Li+, Na+, H3O+, Ag+ and K+) ΔG0 values are positive, as expected, whereas for reactions involving Rb+, Cs+ and T1+, ΔG0 values are negative. Variations in enthalpy and entropy terms for the various exchange reactions are discussed in terms of the energies required to remove the hydration shells of ingoing ions relative to that of the NH4+ ions and the energy term for the electrostatic interaction between the cations and the lattice anions. (author)

  1. Insoluble polyelectrolyte and ion-exchange hollow fiber impregnated therewith

    Rembaum, A. (Inventor)

    1977-01-01

    The number of quaternary sites and ion exchange capacity of a polyquaternary, cross linked, insoluble copolymer of a vinyl pyridine and a dihalo organic compound is increased by about 15-35% by reaction of the polymer with an amine followed by quaternization, if required. The polymer forms spontaneously in the presence of a substrate such as within the pores of a hollow fiber. The improved resin impregnated fiber may be utilized to remove ions from waste or process steams.

  2. Alkaline Anion-Exchange Membranes Containing Mobile Ion Shuttles.

    Ge, Xiaolin; He, Yubin; Guiver, Michael D; Wu, Liang; Ran, Jin; Yang, Zhengjin; Xu, Tongwen

    2016-05-01

    A new class of alkaline anion-exchange membranes containing mobile ion shuttles is developed. It is achieved by threading ionic linear guests into poly(crown ether) hosts via host-guest molecular interaction. The thermal- and pH-triggered shuttling of ionic linear guests remarkably increases the solvation-shell fluctuations in inactive hydrated hydroxide ion complexes (OH(-) (H2 O)4 ) and accelerates the OH(-) transport. PMID:26972938

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

    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+,

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

    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.

  5. Kinetics, equilibrium and isotope exchange in ion exchange systems Pt. 3

    The kinetics of isotope exchange in the sup(23)Na-sup(22)Na strongly acidic cation exchanger system was studied in a batch stirred reactor. Samples of exchangers OSTION KS (containing divinylbenzene (DVB) in the range of 1.5-12%) and AMBERLITE IR 120 were used for experimental work. In all cases the concentration of the aqueous solution was 02.M NaNOsub(3). Fick's equation was used for the description of diffusion of ions in the particle. By evaluating the experimental data, values were obtained for the self-diffusion coefficients of sodium ions in the exchangers and their dependences on the content of DVB and on the concentration of functional groups in the resin particle. (author)

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

    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 104 , 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

  7. Studies on the ion-exchange behaviour of chromium ferrocyanide

    The sorption of univalent, bivalent and trivalent ions has been studied on chromium ferrocyanide gel. The distribution of various metal cations were determined by shaking the exchanger (0.1 g) and 20 ml of 0.005M metal ion solution of pH 2-3, till equilibrium was attained. The concentration of Pb2+, Cu2+, Mn2+, Ni2+, Mg2+ and Al3+ were determined by EDTA, ZrO2+, Th4+, UO2+ and Fe2+ were estimated spectrophotometrically and radiometric methods were used for Rb+, Cs+, Tl+, Ag+, Zn2+, Co2+, Cd2+, Hg2+ and Fe3+ metal ions. The distribution coefficients of various univalent, bivalent and trivalent metal ions (0.002M) were also determined as a function of NH4NO3 and HNO3 concentrations and pH. The studies reveal a high sorption capacity for Cs+, Tl+, Ag+, Cu2+, Zn2+, Cd2+, Fe3+ and Th4+. The sorption of monovalent cations show purely ion exchange mechanism while the uptake of bivalent and trivalent cations is non-equivalent in nature. Single elution of Rb+, Cs+ and Tl+ has been performed from the columns of this exchanger and the recovery is almost complete in all the cases. Cu2+ and Ag+ get completely adsorbed on the gel column and their elution is not possible probably due to the formation of some new solid phases. Depending on the Ksub(d) values of the metal ions, a large number of separations of radiochemical as well as analytical importance can be performed on the columns of this exchanger material. It is apparent from the Ksub(d) values that a number of separations as Hg2+ from Mg2+, Ca2+ and Pb2+; Mg2+ from Mn2+: Fe3+ from Al3+; and Th4+ from ZrO2+ can be performed on the columns of this exchanger. (T.G.)

  8. Microspheres aided introduction of ionophore and ion-exchanger to the ion-selective membrane.

    Wojciechowski, Marcin; Kisiel, Anna; Bulska, Ewa; Michalska, Agata

    2012-01-15

    In this work a novel method for introduction of ionophore and ion-exchanger to the ion-selective polyacrylate based membrane is proposed. These compounds (and optionally primary ions) are introduced to polyacrylate microspheres, used to prepare ion-selective membrane. The approach proposed here can be used to prepare membranes containing primary ions equally distributed through the receptor phase, i.e. membranes that do not require conditioning in primary ions solution and are free from problems related to slow diffusion of primary ions. Thus obtained sensors were characterized with linear responses (also at relatively high activities) and high selectivities, despite considerable reduction of ionophore and ion-exchanger amount introduced to the membrane. To be able to prepare ion-selective membranes using this approach, a method for quantification of ionophore and ion-exchanger introduced into microspheres is required. In this work a novel method utilizing high performance liquid chromatography (HPLC) with DAD or FLD detection is proposed. Incorporation of ionophore and ion-exchanger into the microspheres was achieved either by absorption into ready spheres or in course of photopolymerization of polymeric beads. The obtained results have proven that both procedures led to incorporation of ionophore/ion-exchanger into polymeric spheres, however, the content of the compounds in the spheres post process is different from their ratio in solution from which they had been introduced. These effects need to be considered/compensated while preparing microspheres containing ion-selective membranes. As a model system poly(n-butyl acrylate) spheres, silver selective ionophore and sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate were chosen, resulting ultimately in silver-selective electrodes. PMID:22265471

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

    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

  10. Ion exchange kinetics of alkaline earth metals on acrylamide zirconium(IV) phosphate cation exchanger

    The kinetics of Mg(II), Ca(II), Sr(II) and Ba(II) exchange with H(I) on acrylamide zirconium(IV) phosphate has been studied applying the Nernst-Planck equation. The rate of exchange is found to be particle diffusion controlled at a metal ion concentration ≥ 0.01M in aqueous medium. The energy and entropy of activation vary linearly with the ionic radii and mobilities. (author)

  11. Charge exchange between hydrogen atoms and fully stripped heavy ions

    Charge exchange between multicharged ions and background atomic and molecular gases represents one of the limitations to the attainment of high charge states in heavy ion sources, particularly containment sources. An attempt is made to study systematically a particularly simple but in many respects representative class of such reactions, namely charge transfer between atomic hydrogen and fully stripped heavy ions. Approximate cross sections for these processes in the low keV range of collision energies were obtained using a multistate Landau--Zener method. The energy and Z dependences of the cross sections are discussed

  12. DEVELOPMENT OF INORGANIC ION EXCHANGERS FOR NUCLEAR WASTE REMEDIATION

    This research is concerned with the development of highly selective inorganic ion exchangers for the removal of primarily Cs+ and Sr2+ from nuclear tank waste and from groundwater. In this study, we will probe the, origins of selectivity through detailed structural studies and th...

  13. Ion exchange technology in the nuclear fuel cycle

    The application of ion exchange has been expanded to various parts of the nuclear fuel cycle. Major applications are in uranium production facilities, nuclear power plants, spent fuel reprocessing and waste treatment. Furthermore, application to isotope separation has been under development. The appendix contains a compilation of resin data. A separate abstract was prepared for each of the 6 chapters in this technical document

  14. Ion exchange in a zeolite-molten chloride system

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

  15. Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR

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

    2008-01-01

    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

  16. Increasing selectivity of a heterogeneous ion-exchange membrane

    Křivčík, J.; Neděla, D.; Hadrava, J.; Brožová, Libuše

    2015-01-01

    Roč. 56, č. 12 (2015), s. 3160-3166. ISSN 1944-3994. [International Conference on Membrane and Electromembrane Processes - MELPRO 2014. Prague, 18.05.2014-21.05.2014] Institutional support: RVO:61389013 Keywords : ion-exchange membrane * selectivity * permselectivity Subject RIV: JP - Industrial Processing Impact factor: 1.173, year: 2014

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

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

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

    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

  19. Determination of boron in silicates after ion exchange separation

    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. Cesium Ion Exchange Using Tank 241-AN-104 Supernate

    The River Protection Project is to design and build a high level nuclear waste treatment facility. The waste treatment plant is to process millions of gallons of radioactive waste stored in tanks at the Hanford Site. The high level nuclear waste treatment process includes various unit operations, such as ultrafiltration, precipitation, evaporation, ion exchange, and vitrification. Ion exchange is identified as the optimal treatment method for removal of cesium-137 and Tc-99 from the waste. Extensive ion exchange testing was performed using small-scale columns with actual waste samples. The objectives of this study were to: demonstrate SuperLig 644 ion exchange performance and process steps for the removal of cesium from actual AN-104 tank waste; pretreat actual AN-104 tank waste to reduce the concentration of cesium-137 in the waste below LAW vitrification limit; produce and characterize cesium eluate solutions for use in eluate evaporation tests. The experiments consisted of batch contact and small-scale column tests. The batch contact tests measured sorption partition coefficients Kds. The Kds were used to predict the effective resin capacity. The small-scale column tests, which closely mimic plant conditions, generated loading and elution profile data used to determine whether removal targets and design requirements were met

  1. Field experiment on multicomponent ion exchange in a sandy aquifer

    A field experiment is performed in a sandy aquifer in order to study ion exchange processes and multicomponent solute transport modeling. An injection of groundwater spiked with sodium and potassium chloride was performed over a continuous period of 37 days. The plume is monitored by sampling 350 filters in a spatial grid. The sampling aims at establishing compound (calcium, magnesium, potassium, sodium, chloride) breakthrough curves at various filters 15 to 100 m from the point of injection and areal distribution maps at various cross sections from 0 to 200 m from the point of injection. A three-dimensional multicomponent solute transport model will be used to model the field experiments. The chemical model includes cation exchange, precipitation, dissolution, complexation, ionic strength and the carbonate system. Preliminary results from plume monitoring show that the plume migration is relatively well controlled considering the scale and conditions of the experiment. The transverse dispersion is small causing less dilution than expected. The ion exchange processes have an important influence on the plume composition. Retardation of the injected ions is substantial, especially for potassium. Calcium exhibits a substantial peak following chloride due to release from the ion exchange sites on the sediment. (Author) (8 refs., 5 figs., tab.)

  2. Direct measurement of birefringence in ion-exchanged planar waveguides

    Fazio, E.; Ramadan, W. A.; Bertolotti, M.; Righini, G. C.

    1996-08-01

    A direct measurement of the birefringence of a planar waveguide obtained by Na+ - K + ion exchange was performed with a double Lloyd interferometer. The results are compared with those obtained by a round-robin test involving the same sample. Birefringence of as much as Delta n=(2.0+/-0.2) \\times 10-3 was measured.

  3. Ion-exchanged Nd:glass tapered waveguide laser

    Hettrick, S.J.; Mackenzie, J.I.; Wilkinson, J.S.; Tropper, A.C.; Shepherd, D.P.

    2000-01-01

    We report an efficient (>40% slope) and low threshold (~10mW) ion-exchanged Nd:glass tapered waveguide laser with near-diffraction-limited output. This structure is compatible with high-power, broad-stripe, diode pumping.

  4. Adsorption Assisted Ion Exchanger Catalyst for Fatty Acid Esterification

    Jeřábek, Karel; Holub, Ladislav; Hanková, Libuše; Corain, B.; Centomo, P.

    - : -, 2011, s. 18. ISBN N. [IUPAC International Conference on Chemical Research Applied to World Needs /19./. Kuala Lumpur (MY), 27.09.2011-29.09.2011] Institutional research plan: CEZ:AV0Z40720504 Keywords : ion exchanger * catalysts * acid esterification Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  5. Pyrolysis of ion exchange resins for volume reduction and inertisation

    Radioactive ion exchange resins are produced in water cleaning systems in nuclear power plants. Studsvik RadWaste AB and GNS have developed a pyrolysis process for the treatment of resins with the goal of an optimal volume reduction and a transformation of the ion exchange resins into a biological and chemical inert state. The degradation products arising from the pyrolysis are char, tar and gas. In the pyrolysis process used by Studsvik RadWaste and GNS about 1/3 char, 1/3 water and tar and 1/3 gas are produced. The char is supercompacted in order to receive a volume reduction of about 10:1 and a better product for final storage. Ion exchange resins with a specific β/γ activity of 1E12 Bq/m3 with 50% of Co-60 can be handled. The retention of the activity has been 0.5E6:1. By processing a total of 100 kg ion exchange resins with a total activity of IE9 Bq only some hundred becquerel have been monitored outside the pyrolyzing unit. This means that the products leaving the pyrolyzing unit, in this case tar, water and gas could be handled as non radioactive material in a conventional waste treatment facility

  6. Ion Exchanger Catalyst Modification for Reactions Involving Lipophilic Reagents

    Hanková, Libuše; Holub, Ladislav; Jeřábek, Karel

    Bratislava: Slovak Society of Chemical Engineering, 2011 - (Markoš, J.), s. 229 ISBN 978-80-227-3503-2. [International Conference of Slovak Society of Chemical Engineering /38./. Tatranské Matliare (SK), 23.05.2011-27.05.2011] Institutional research plan: CEZ:AV0Z40720504 Keywords : ion exchangers * catalysts * lipophilic Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  7. Essays in applied macroeconomics: Asymmetric price adjustment, exchange rate and treatment effect

    Gu, Jingping

    This dissertation consists of three essays. Chapter II examines the possible asymmetric response of gasoline prices to crude oil price changes using an error correction model with GARCH errors. Recent papers have looked at this issue. Some of these papers estimate a form of error correction model, but none of them accounts for autoregressive heteroskedasticity in estimation and testing for asymmetry and none of them takes the response of crude oil price into consideration. We find that time-varying volatility of gasoline price disturbances is an important feature of the data, and when we allow for asymmetric GARCH errors and investigate the system wide impulse response function, we find evidence of asymmetric adjustment to crude oil price changes in weekly retail gasoline prices. Chapter III discusses the relationship between fiscal deficit and exchange rate. Economic theory predicts that fiscal deficits can significantly affect real exchange rate movements, but existing empirical evidence reports only a weak impact of fiscal deficits on exchange rates. Based on US dollar-based real exchange rates in G5 countries and a flexible varying coefficient model, we show that the previously documented weak relationship between fiscal deficits and exchange rates may be the result of additive specifications, and that the relationship is stronger if we allow fiscal deficits to impact real exchange rates non-additively as well as nonlinearly. We find that the speed of exchange rate adjustment toward equilibrium depends on the state of the fiscal deficit; a fiscal contraction in the US can lead to less persistence in the deviation of exchange rates from fundamentals, and faster mean reversion to the equilibrium. Chapter IV proposes a kernel method to deal with the nonparametric regression model with only discrete covariates as regressors. This new approach is based on recently developed least squares cross-validation kernel smoothing method. It can not only automatically smooth

  8. Ion-exchange behavior of alkali metals on treated carbons

    The ion-exchange behavior of trace quantities of the alkali-metal ions sodium and cesium, on activated carbon impregnated with zirconium phosphate (referred to here as ZrP), was studied. Impregnated carbon had twice as much ion-exchange activity as unimpregnated, oxidized carbon, and 10 times as much as commercial activated carbons. The distribution coefficient of sodium increased with increasing pH; the distribution coefficient of cesium decreased with increasing pH. Sodium and cesium were separated with an electrolytic solution of 0.1 M HCl. Preliminary studies indicated that 0.2 M potassium and cesium can also be separated. Distribution coefficients of the supported ZrP were determined by the elution technique and agreed within 20% of the values for pure ZrP calculated from the literature

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

    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. PMID:22827724

  10. Ion-exchange membranes in chemical synthesis – a review

    Jaroszek Hanna

    2016-12-01

    Full Text Available The applicability of ion-exchange membranes (IEMs in chemical synthesis was discussed based on the existing literature. At first, a brief description of properties and structures of commercially available ion-exchange membranes was provided. Then, the IEM-based synthesis methods reported in the literature were summarized, and areas of their application were discussed. The methods in question, namely: membrane electrolysis, electro-electrodialysis, electrodialysis metathesis, ion-substitution electrodialysis and electrodialysis with bipolar membrane, were found to be applicable for a number of organic and inorganic syntheses and acid/base production or recovery processes, which can be conducted in aqueous and non-aqueous solvents. The number and the quality of the scientific reports found indicate a great potential for IEMs in chemical synthesis.

  11. Ion-Exchange Processes and Mechanisms in Glasses

    Leaching of alkalis from glass is widely recognized as an important mechanism in the initial stages of glass-water interactions. Pioneering experimental studies [1-3] nearly thirty-five years ago established that alkali (designated as M+) are lost to solution more rapidly than network-forming cations. The overall chemical reaction describing the process can be written as: (triplebond)Si-O-M + H+ → (triplebond)Si-OH + M+ (1) or (triplebond)Si-O-M + H3O+ → (triplebond)Si-OH + M+ + H2O. (2) Doremus and coworkers [4-7] fashioned a quantitative model where M+ ions in the glass are exchanged for counter-diffusing H3O+ or H+. Subsequent investigations [8], which have relied heavily on reaction layer analysis, recognized the role of H2O molecules in the alkali-exchange process, without minimizing the importance of charged hydrogen species. Beginning in the 1980s, however, interest in M+-H+ exchange reactions in silicate glasses diminished considerably because important experimental observations showed that network hydrolysis and dissolution rates were principally controlled by the chemical potential difference between the glass and solution (chemical affinity) [9]. For nuclear waste glasses, formation of alteration products or secondary phases that remove important elements from solution, particularly Si, was found to have very large impacts on glass dissolution rates [10,11]. Consequently, recent work on glass/water interactions has focused on understanding this process and incorporating it into models [12]. The ion-exchange process has been largely ignored because it has been thought to be a short duration, secondary or tertiary process that had little or no bearing on long-term corrosion or radionuclide release rates from glasses [13]. The only significant effect identified in the literature that is attributed to alkali ion exchange is an increase in solution pH in static laboratory tests conducted at high surface area-to-volume ratios [14,15]. Renewed interest in

  12. Highly sensitive determination of hydrazine ion by ion-exclusion chromatography with ion-exchange enhancement of conductivity detection.

    Mori, Masanobu; Tanaka, Kazuhiko; Xu, Qun; Ikedo, Mikaru; Taoda, Hiroshi; Hu, Wenzhi

    2004-06-11

    An ion-exclusion chromatography method with ion-exchange enhancement of conductivity was developed for the selective separation and sensitive determination of hydrazine ion from alkali/alkaline earth metal cations and ammonium ion. Hydrazine ion was separated by ion-exclusion/penetration effect from other cations on a weakly basic anion-exchange column in the OH- form (TSKgel DEAE-5PW). Moreover, two different ion-exchange resin columns were inserted between the separating column and conductimetric detector in order to improve the sensitivity of hydrazine ion. The first enhancement column packed with a strongly basic anion-exchange resin in the SO4(2-) form (TSKgel SAX) for hydrazine ion can convert from N2H5OH to (N2H5)2SO4. Moreover, the second enhancement column packed with a strongly acidic cation-change resin in the H+ form (TSKgel SCX) can convert to H2SO4. As a result, the sensitivity of hydrazine ion using two conductivity enhancement columns could be 26.8-times greater than using the separating column alone. This method was effectiveness also for the enhancement of ammonium ion (6.1-times) and sodium ion (1.2-times). The calibration graph of hydrazine ion detected as H2SO4 was linear over the concentration range of 0.001-100 ppm (r2 = 0.9988). The detection limit of hydrazine ion in this system was 0.64 ppb. Therefore, hydrazine ion in real boiler water sample could be accurately determined, avoiding the interference of other cations. PMID:15250415

  13. Low-level radioactive wastes bituminization - ion exchange resins

    The present work describes the research and development of low level radioactive waste treatment by bituminization process in Nuclear Technology Development Centre (CDTN). Low level radioactive solid waste was simulated by mixed ion exchange resin. Cation exchange and anion resin were loaded with lithium and boric acid respectively and were incorporated in bitumen of suitable rheological properties. The simulated solid wastes incorporated in bitumen were 30 to 46 weight %. The rheological properties of waste product bitumen-mixed resin have been reported. The waste product with bitumen V-65 showed best physical and rheological properties and grave lowest leaching rates of boron and lithium. (author)

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

    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 ion...... 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....

  15. Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR

    Delabie, E.; Jaspers, R.J.E.; von Hellermann, M.G.;

    2008-01-01

    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 D-alpha spectrum while the beam emission spectrum is Doppler shifted to the red wing. An analysis combining the two......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...... 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...

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

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

    1978-01-01

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

  17. Ion exchange at the critical point of solution.

    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. PMID:26884137

  18. Radiation degradation in EPICOR-2 ion exchange resins

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

    1990-09-01

    The Low-Level Waste Data base Development -- EPICOR-II Resin/Liner Investigation Program funded by the US Nuclear Regulatory Commission is investigating chemical and physical conditions for organic ion exchange resins contained in several EPICOR-II prefilters. Those prefilters were used during cleanup of contaminated water from the Three Mile Island Nuclear Power Station after the March 1979 accident. The work was performed by EG G Idaho, Inc. at the Idaho Engineering Laboratory. This is the final report of this task and summarizes results and analyses of three samplings of ion exchange resins from prefilters PF-8 and -20. Results are compared with baseline data from tests performed on unirradiated resins supplied by Epicor, Inc. to determine the extent of degradation due to the high internal radiation dose received by the organic resins. Results also are compared with those of other researchers. 18 refs., 23 figs., 7 tabs.

  19. Method of eluting radioactive nuclide from spent ion exchange resin

    Highly radioactive spent ion exchange resins containing a great amount of cesium or strontium as radioactive nuclides are immersed in an eluting solution and, by stirring solution, cesium or strontium adsorbed to the spent ion exchange resins are eluted. The eluting solution is passed through a zeolite bed to selectively remove cesium and/or strontium. As an eluent for the eluting solution to be used, sodium salts such as sodium hydroxide or sodium sulfate is preferred. Zeolite having radiation resistance and not suffering from reduction in the absorbent performance by the presence of boric acid or sodium are used. Since the zeolite is highly stabilized with inorganic material by cement or glass solidification, the amount is remarkably reduced as compared with that of the spent resins and the administration is facilitated. (K.M.)

  20. Radiation degradation in EPICOR-2 ion exchange resins

    The Low-Level Waste Data base Development -- EPICOR-II Resin/Liner Investigation Program funded by the US Nuclear Regulatory Commission is investigating chemical and physical conditions for organic ion exchange resins contained in several EPICOR-II prefilters. Those prefilters were used during cleanup of contaminated water from the Three Mile Island Nuclear Power Station after the March 1979 accident. The work was performed by EG ampersand G Idaho, Inc. at the Idaho Engineering Laboratory. This is the final report of this task and summarizes results and analyses of three samplings of ion exchange resins from prefilters PF-8 and -20. Results are compared with baseline data from tests performed on unirradiated resins supplied by Epicor, Inc. to determine the extent of degradation due to the high internal radiation dose received by the organic resins. Results also are compared with those of other researchers. 18 refs., 23 figs., 7 tabs

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

    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. Sorption properties of radiation-cross-linked polymer hydrogels containing ion-exchange fibers

    Rezvova, M. A.; Zhevnyk, V. D.; Pak, V.; Borodin, Y. V.; Kachina, E. V.

    2016-02-01

    Polymer hydrogel modification for soft contact lenses by ion-exchange fibers was studied in this work. The obtained results showed that the ion-exchange fiber modifiers have a number of advantages as compared with ion-exchange resin modifiers.

  3. Preparation of Nafion 117™-SnO2 Composite Membranes using an Ion-Exchange Method

    Nørgaard, Casper Frydendal; Nielsen, Ulla Gro; Skou, Eivind Morten

    2012-01-01

    Nafion 117™-SnO2 composite membranes were prepared by in-situ particle formation using an ion-exchange method. SnO2 was incorporated into Nafion 117ä membranes by ion-exchange in solutions of SnCl2 ∙2 H2O in methanol, followed by oxidation to SnO2 in air. By adjustment of the concentration of SnCl2...... ∙ 2 H2O used in the ion-exchange step, compositions ranging from 2 to 8 wt% SnO2 with SnO2 homogeneously distributed as nanoparticles were obtained. The prepared nanocomposite membranes were characterized by powder XRD, 119Sn MAS NMR spectroscopy, electrochemical impedance spectroscopy, water uptake......, tensile stress-strain measurements and thermogravimetric analysis. A SnO2 content around 4 wt% gave a significant increase in membrane stiffness without losses in conductivity....

  4. Trade Adjustments to Exchange Rate Changes by Japanese Manufacturing MNEs: Intra-firm and arm's length transactions

    Ando, Mitsuyo; Fukunari KIMURA

    2013-01-01

    This paper examines how Japanese manufacturing multinational enterprises (MNEs) adjust to exchange rate changes. Using the micro-data of Japanese manufacturing MNEs from 1994 to 2010, we find that exports tend to respond to exchange rate changes, in particular when wholly or majority-owned affiliates are dominant among their foreign affiliates and when intra-firm trade ratios are higher. Moreover, the responsiveness to exchange rate changes is higher for intra-firm exports than for total expo...

  5. Modeling and Predicting the EUR/USD Exchange Rate: The Role of Nonlinear Adjustments to Purchasing Power Parity

    Jesús Crespo Cuaresma; Anna Orthofer

    2010-01-01

    Reliable medium-term forecasts are essential for forward-looking monetary policy decisionmaking. Traditionally, predictions of the exchange rate tend to be linked to the equilibrium concept implied by the purchasing power parity (PPP) theory. In particular, the traditional benchmark for exchange rate models is based on a linear adjustment of the exchange rate to the level implied by PPP. In the presence of aggregation effects, transaction costs or uncertainty, however, economic theory predict...

  6. Charge-exchange collision dynamics and ion engine grid geometry optimization

    Morris, Bradford

    The development of a new three-dimensional model for determining the absolute energy distribution of ions at points corresponding to spacecraft surfaces to the side of an ion engine is presented. The ions resulting from elastic collisions, both charge-exchange (CEX) and direct, between energetic primary ions and thermal neutral xenon atoms are accounted for. Highly resolved energy distributions of CEX ions are found by integration over contributions from all points in space within the main beam formed by the primary ions.The sputtering rate due to impingement of these ions on a surface is calculated. The CEX ions that obtain significant energy (10 eV or more) in the collision are responsible for the majority of the sputtering, though this can depend on the specific material being sputtered. In the case of a molybdenum surface located 60 cm to the side of a 30 cm diameter grid, nearly 90% of the sputtering is due to the 5% of ions with the highest collision exit energies. Previous models that do not model collision energetics cannot predict this. The present results agree with other models and predict that the majority of the ion density is due to collisions where little to no energy is transferred.The sputtering model is combined with a grid-structure model in an optimization procedure where the sputtering rate at specified locations is minimized by adjustment of parameters defining the physical shape of the engine grids. Constraints are imposed that require that the deflection of the grid under a specified load does not exceed a maximum value, in order to ensure survivability of the grids during launch. To faciliate faster execution of the calculations, simplifications based on the predicted behavior of the CEX ions are implemented. For diametrically opposed sputtering locations, a rounded barrel-vault shape reduces the expected sputtering rate by up to 30% in comparison to an NSTAR-shaped grid.

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

    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

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

    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.

  9. STIRRED FLUIDIZED-BED DRYER OF REGENERATED ION EXCHANGER PARTICLES

    Michal Pěnička; Pavel Hoffman; Ivan Fořt

    2014-01-01

    This article describes intensification of the fluidized-bed drying process for regenerated spherical-shape ion exchanger particles in the batch mode, achieved by a mechanical stirrer in the fluidized bed layer of the dried particles. The effect of the mechanical stirring system on the drying process was examined. Calculations as well as results of comparison measurements provide evidence of a favourable effect of stirring on the total drying time as compared to the initial unstirred system. T...

  10. Selective ion exchange onto Slovakian natural zeolites in aqueous solutions

    Ion exchange isotherms have been measured and plotted for the uptake of cesium, barium, cobalt, zinc, silver and ammonium onto clinoptilolite- and mordenite-rich tuffs of Slovakian origin selectively for both the natural and near homoionic Na form as well, using the radioanalytical determination. The higher quality clinoptilolite-rich tuff has been proven to be effective for a potential radionucleides removal in native form according to the following selectivity sequence: Ag+,Ba2,Cs+>NH4+>Co2+, while parent tuff in Na exchanged variety exhibited a little different sequence according to: Ag+ > NH4+ > Ba2+ > Cs+. The raw and Na exchanged mordenite-rich tuffs proved subsequently more or less similar selectivity: Ag+ > Zn2+ > Cs+, Ba2+ > Co2+ and Ag+ > Zn2+. (author)

  11. Ion exchange resin fouling of molybdenum in recovery uranium processess

    The relationship between anion exchange resin fouling and molybdic acid polymerization was studied. By using potentiometer titration and laser-Raman spectroscopy the relationship of molybdic acid polymerization and the pH value of solution or the molybdenum concentration was determined. It was shown that as the concentration of initial molybdenum in solution decreases from 0.2 mol/L to 0.5 mmol/L, the pH value of starting polymerization decreased from 6.5 to 4.5. The experimental results show that the fouling of 201 x 7 resin in the acidic solution is mainly caused by the adsorbing of Mo3O264- ion and occupying the exchange radical site of the resin. Under the leaching conditions the molybdenum and phosphate existing in the leaching liquor can form 12-molybdo-phosphate ion. It also leads to resin fouling. The molybdenum on the fouled resin can synergically be desorbed by mixed desorbents containing ammonium hydroxide and ammonium sulfate. The desorbed resin can be used for uranium adsorption and the desorbed molybdenum can be recovered by ion exchange method

  12. Solidification of ion exchange powder in sodium water-glasses

    Ion exchange materials loaded with radioactive isotopes are produced in several processes along the nuclear fuel cycle. The aim of this study is to investigate the possibility of solidifying ion exchanger in water glass to replace cement. Ion exchange powder was loaded with radioactive Cs-137 and Sr-90, solidified in sodium water glasses, hardened with AlPO4 and leached in water and Q-brine at 50oC. Control samples were made of high alumina cement under similar conditions. Tolerance of solidified matrix to water was quite adequate. Samples maintained their shape and dimensions to the end of the experiments. In Q-brine, samples were cracked or broken to small pieces within the first week. The fraction of Cs leached into Q-brine was 70-90% and not more than 14% in water. 15% of the strontium leached into Q-brine and less than 0.4% leached into water. Sodium water-glass was shown to be superior phase in water, while cement behaved better in Q-brine. (author) 4 figs., 1 tab., 5 refs

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

    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].

  14. Adjustment of threshold voltage of MOS devices by ion implantation

    In this paper we report the effect of oxide thickness, implant energy and dose on threshold voltage shift Δ Vsub(T). The implant parameters e.g. stopping power, projected range, straggle and the energy loss per micron for an ion in the substrate lattice are calculated using the WHB potential. The junction depth beneath the oxide semiconductor surface is calculated using a two layer model. The parameters are then used in a theoretical calculation of threshold shift of MOS devices. Experimental threshold voltages for unimplanted and implanted samples were obtained from C-V plots, showing fairly good agreement with theory. (author)

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

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

  16. Negative Joule Heating in Ion-Exchange Membranes

    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.

  17. Charge exchange measurements of ion behavior in the ISX tokamak

    Analysis of charge exchange neutrals is the standard method for measuring ion behavior in tokamak plasmas. Limitations of this technique, which arise in dense and neutral-beam-heated plasmas, are discussed. Two refinements that address these limitations are described: a neutral particle analyzer, which incorporates both mass and energy resolution to distinguish different ion components such as the fast and thermal ions in beam-heated plasmas, and an improved data analysis procedure, which accounts for the effects of profiles and neutral attenuation in dense plasmas. A simple two-dimensional Monte Carlo neutral transport code was developed and used to investigate the effects of toroidally asymmetric neutral density profiles. Applications of these methods to experiments in the Impurity Study Experiment (ISX) are discussed; they include energy confinement studies on ISX-A, natural beam heating and high beta studies on ISX-B, and pellet fueling studies on ISX-B

  18. A study on free radical oxidation of spent radioactive ion-exchange resins

    The resin dissolution process was conducted successfully in bench-scale tests. The polystyrene based strong acid cation-exchange resins with water content of about 58% (wt) were dissolved by hydrogen peroxide and ferrous ions as catalyst under pH of 2.0∼3.0 adjusted by sulphuric acid. For the same objective of dissolution of the strong basic anion-exchange resins with water content about 63% (wt), citric acid was the best choice for pH control, and the use of Fe2+ and Cu2+ was verified having a synergetic effect. Mixed resins were also dissolved successfully under proper conditions. The dissolution temperature was generally below 99 degree C. The COD and TOC levels of the dissolution residues depended on the doses and dosing rate of hydrogen peroxide as well as the catalyst supplied. All the three types of dissolution reactions gave the similar degradation pattern

  19. Chlorine isotope effects in ion exchange reactions with a strongly basic anion exchanger

    As can be shown by the results of this study, the chemical preenrichment of the stable chlorine isotopes in inorganic ion-exchange equilibria is feasible in principle. This process should be performed in chromotographic separation columns at temperatures as low as possible. Because of the dependence of the isotopic effect on the elution medium concentration a very low concentration is desirable for the chemical enrichment process. Smaller elution concentrations however result in increasingly longer elution times. (HK)

  20. Possibility of sorption purification of chromium comprising waste waters of galvanic production by inorganic ion exchangers

    Present work is devoted to possibilities of sorption purification of chromium comprising waste waters of galvanic production by inorganic ion exchangers. Thus, the comparative study of sorption of chromium ions on anion exchanger A B-17 and on inorganic ion exchangers on the basis of hydrated titanium and zirconium dioxides in static and dynamic conditions is conducted. The influence of chromium ions concentration, solutions acidity (ph=1÷12) and presence of base electrolyte on sorption is studied. The state of chromium ions sorbed by inorganic ion exchangers is studied by means of infrared spectroscopy and spectroscopy. It is defined that inorganic sorbents could be used for chromium extraction from different solutions.

  1. Operation and control of ion-exchange processes for treatment of radioactive wastes

    A manual dealing with the application of ion-exchange materials to the treatment of radioactive wastes and reviewing the facilities currently using this method. This book is one of three commissioned by the IAEA on the principal methods of concentrating radioactive wastes. The content of this document is: (i) Historical review related to removal of radioactivity; (ii) Principles of ion exchange (iii) Ion-exchange materials; (iv) Limitations of ion exchangers; (v) Application of ion exchange to waste processing; (vi) Operational procedures and experiences; (vii) Cost-of-treatment by ion-exchange. The document also gives a list of producers of ion-exchange material and defines some relevant terms. 101 refs, 31 figs, 27 tabs

  2. Respective influence of thermodynamic, hydrodynamic and diffusion factors on ion exchanger operation. Application to the ion exchanger NYMPHEA

    Nymphea is an annular ion exchanger, with a resin bed 30 centimeter-thick, used for purification of the water from the spent fuel storage pool at La Hague reprocessing plant. Very low concentration solutions (10-12 eq/l for cobalt) are purified by Nymphea, and parameter must be extrapolated from the range 0.01 - 0.0001 eq/l to very low concentrations. A model is developed, describing ion state inside the grains. The limiting step in Nymphea operation is external diffusion. Diffusion time is determined by mean grain size which should be accurately defined for extrapolation of results from monodispersed distribution (often the case in laboratories) to polydispersed (often the case in industry). Operation of an ion exchanger can be simulated for any ion number in solution. In steady state condition of concentration pool purification increases with flow rate. Simulation in transient operation allows the determination of all the concentrations in function of time and hence to calculate the time to reach the maximum permissible concentration for cobalt. This time depends upon calcium pollution (by fuel can dissolution, atmospheric pollution) which is not accurately known

  3. Continuous ion exchange separation of zirconium and hafnium

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

  4. Novel ion exchange chromatographic method using conductimetric detection

    Ion exchange resins have a well known ability to provide excellent separation of ions, but the automated analysis of the eluted species is often frustrated by the presence of the background electrolyte used for elution. A novel combination of resins succeeded in neutralizing or suppressing this background without significantly affecting the species being analyzed which in turn permits the use of a conductivity cell as a universal and very sensitive monitor of all ionic species either cationic or anionic. Using this technique, automated analytical schemes were devised for Li+, Na+, K+, Rb+, Cs+, NH4+, Ca2+, Mg2+, F-, Cl-, Br-, I-, NO3-, NO2-, SO42-, SO32-, PO43- and many amines, quaternary ammonium compounds, and organic acids. Elution time can take as little as 1.0 min/ion and is typically 3 min/ion. Ions were determined in a diversity of backgrounds, e.g., waste streams, various local-surface waters, blood serum, urine, and fruit juices. (U.S.)

  5. High ionic strength narrows the population of sites participating in protein ion-exchange adsorption: A single-molecule study

    Kisley, Lydia; Chen, Jixin; Mansur, Andrea P.; Dominguez-Medina, Sergio; Kulla, Eliona; Kang, Marci; Shuang, Bo; Kourentzi, Katerina; Poongavanam, Mohan-Vivekanandan; Dhamane, Sagar; Willson, Richard C.; Landes, Christy F.

    2014-01-01

    The retention and elution of proteins in ion-exchange chromatography is routinely controlled by adjusting the mobile phase salt concentration. It has repeatedly been observed, as judged from adsorption isotherms, that the apparent heterogeneity of adsorption is lower at more-eluting, higher ionic strength. Here, we present an investigation into the mechanism of this phenomenon using a single-molecule, super-resolution imaging technique called motion-blur Points Accumulation for Imaging in Nan...

  6. Fractionation of inorganic arsenic by adjusting hydrogen ion concentration.

    Oliveira, Andrea; Gonzalez, Mario Henrique; Queiroz, Helena Müller; Cadore, Solange

    2016-12-15

    The inorganic fraction of arsenic species, iAs=∑[As(III)+As(V)] present in fish samples can be quantified in the presence of other arsenic species also found in fishes, such as: monomethylarsonic acid (MMA), dimethylarsinic acid (DMA) and arsenobetaine (AsB). The toxic arsenic fraction was selected taking into account the dissociation constants of these arsenic species in different hydrogen ions concentration leading to the arsine formation from iAs compounds detected as As(III) by HG AAS. For thus, a microwave assisted extraction was carried out using HCl 1molL(-1) in order to maintain the integrity of the arsenic species in this mild extraction media. Recovery experiments were done for iAs fraction, in the presence of other arsenic species. The recovery values obtained for iAs fraction added were quantitative about 87-107% (for N=3, RSD⩽3%). The limit of detection (LOD), and the limit of quantification (LOQ), were 5μgkg(-1) and 16μgkg(-1) respectively. PMID:27451157

  7. Ra/Ca separation by ion exchange chromatography

    Ra/Ca separation by ion exchange. The objective of this work was to acquire knowledge of the chromatographic behaviour of the alkaline earth cations calcium, barium and radium and the obtention of well-defined alpha spectra of 226 Ra. Three cationic ion exchange resins (Dower 50 W-X8, AG 50W-XB and Merck I) and three complexing agents (ethylenediaminetetraacetic acid, citric acid and tartaric acid) at various pH values have been investigated. The three types of ions are fixed on the resins at pH 4.8; calcium is eluted at pH between 5 and 6 depending on the resin; barium and radium are eluted at pH values from 8 to 11. Radium is also eluted with a 2 M nitric acid solution, from which it can be electrodeposited on a stainless steel disk potassium fluoride as electrolyte at pH 14. The electrolysis is conducted for 18 hours with a current of mA. Under these conditions high resolution alpha spectra were obtained for 226 Ra, which was practically free from radioactive contaminants (Author)

  8. Separation of cadmium from not waters by ion exchange resins

    The relationship between the ion exchange reaction in a column and temperature was examined in the system cadmium-ion exchanger resin Lewatin S 1080. Cadmium was bound by 0.02 M NHO3 and then eluted by 2.0 M HCl. Working temperature was gradually increased from 273 to 333 K. Cadmium concentrations were determined by atomic absorption spectrometry. Thermostated columns were of our own construction. The distillation plate theory was applied for the same ion eluated at different temperatures. It was necessary to determine graphically the following parameters: cex, cmax, Vmax, and the width of elution band. These parameters obtained for elution curves were related to temperature. The elution curves were found to be temperature specific. Deviations from Gauss normal distribution are larger at higher temperatures. This value can be determined from the segment of the elution curve with the ordinate cmax/e. Consequently, we suggest the width of elution curve to be a measure of elution conditions at higher temperatures. (author). 19 refs, 1 fig., 1 tab

  9. Embedded system for power supply adjuster in radiotherapy with heavy ion

    In order to meet the requirement of exact control for scanning magnet power supply in the device for HITFiL radiotherapy with heavy ion, a kind of digital adjuster for magnet power supply system based on EDA technology is designed. This digital adjuster is completed by using ARM, FPGA and DA/AD technology. Through the test on the spot, the whole system was robust and reliable, satisfied the design requirement, and provided a reliable technique support for the construction and application of radiotherapy with heavy ion equipment. (authors)

  10. The Purification of Residual Waters Using Natural Ion Exchangers

    RUSU T.

    2009-12-01

    Full Text Available Man’s day-by-day activities have a big impact on the environment so we continuously search fordifferent methods of cleaning it. In this paper is studied a very efficient way to purify the residual waters usingnatural ions exchangers. There are made a series of studies above the zeolites, as a class of specific structuresilicates. The main characteristic of the zeolites is the presence of some loose water molecules, the concedingand readmission of these being done without any damage to the crystal lattice. The paper contains a kineticstudy regarding the copper’s elimination from the residual waters, using the Mirsid volcanic tuff. Theexperimental study of the ionic exchange reaction permitted the appraisal of the speed limit stage and theinfluence of the parameters over the purifying process of the residual waters.

  11. Isotopic exchange in ion-molecule reactions: interstellar implications

    The results of a study of the rates of isotopic exchange in several positive ion/molecule reactions are outlined. The data were obtained over the temperature range 90 - 550 K using a SIFT apparatus. Reversible reactions of the kind: 13C+ + 12CO reversible 12C+ + 13CO were studied and the rate coefficients were determined. Other similar reactions studied were those between HCO+ and CO in which the carbon and oxygen were variously isotopically labelled. Differences between the rate coefficients were apparent at the lower temperatures which, it is suggested, contribute to the observed enhanced concentrations of the rarer isotopes in interstellar CO and HCO+. Isotopic exchange in the reactions of CH+, CH2+ and CH3+ with HD and D2 and in the reactions of CD+, CD2+ and CD3+ with HD and H2 has also been studied and these data are briefly discussed. (Auth.)

  12. Ion exchange in ultramarine blue. Studies using radioactive tracers (1963)

    A study has been made of the exchange reaction between the constituent sodium in ultramarine blue, and silver in the form of a silver nitrate solution; an attempt hat been made to define the influence of the solvent of the silver nitrate on the kinetics of the exchange reaction. Five solvents have been used: water, methanol, ethanol, n-propanol and acetone. The reaction rates are controlled by a diffusion process inside the ultramarine grains, whatever the solvent used. It seems that the solvated ionic radius of the diffusing ion is one of the factors influencing the rate of reaction. Furthermore, the solvated ionic radius varies with temperature; this variation is different for each solvent and should explain the differences observed in the activation energies. (author)

  13. Silicate glasses doped with Ag+ ions: The comparisSilicate glasses doped with Ag+ ions: The comparison between the ion-exchange and ion implantationon between the ion-exchange and ion implantation

    Švecová, B.; Nekvindová, P.; Kormunda, M.; Macková, Anna; Malinský, Petr; Pešička, J.; Špirková, J.

    Praha, 2010. s. 139-139. ISBN 978-80-904678-0-4. [SSC-Conference on Solid State Chemistry. 11.09.2010-15.09.2010, Praha] R&D Projects: GA ČR GA106/09/0125; GA MŠk(CZ) LC06041 Institutional research plan: CEZ:AV0Z10480505 Keywords : Silicate glasses * Silver * Ion exchange * Ion implantation Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  14. Improved brine recycling during nitrate removal using ion exchange.

    Bae, Byung-Uk; Jung, Yoo-Hoon; Han, Woon-Woo; Shin, Hang-Sik

    2002-07-01

    Ion exchange technology is currently the best for removing nitrate from drinking water. However, problems related to the disposal of spent brine from regeneration of exhausted resins must be overcome so that ion exchange can be applied more widely and economically, especially in small communities. For this purpose, a novel spent brine recycling system using combined biological denitrification and sulfate reduction processes was developed for more efficient reuse of brine. A granular activated carbon (GAC) adsorption column was introduced as an additional step to prevent contamination of resins by bio-polymers and dissolved organics present in the bio-reactor effluent. Two upflow sludge blanket reactors (USBRs) were operated in series for 166 days to provide denitrification and sulfate reduction. The denitrification reactor provided a nitrate removal efficiency of 96% at a nitrate-N loading rate of 5.4 g NO3(-)-N/l d. The sulfate reduction efficiency of the sulfate reduction reactor remained approximately 62% at a sulfate loading rate of 1.8 g SO4(2-)/l d. Five ion exchange columns containing A520E resins were repeatedly operated in up to 25 cycles of service and regeneration using five kinds of brine: one virgin 3% NaCl and four differently recycled spent brines. Throughput decreased remarkably when the biologically recycled brine was not treated with the GAC column, probably due to the presence of bio-polymers and dissolved organic compounds. The sulfate reduction reactor placed after the denitrification step increased the bicarbonate concentration, which could be used as a co-regenerant with chloride. The inclusion of the sulfate reduction reactor into the conventional brine recycling system allowed more efficient reuse of brine, resulting in both reduced salt consumption and brine discharge. PMID:12188132

  15. Cesium ion exchange using actual waste: Column size considerations

    It is presently planned to remove cesium from Hanford tank waste supernates and sludge wash solutions using ion exchange. To support the development of a cesium ion exchange process, laboratory experiments produced column breakthrough curves using wastes simulants in 200 mL columns. To verify the validity of the simulant tests, column runs with actual supernatants are being planned. The purpose of these actual waste tests is two-fold. First, the tests will verify that use of the simulant accurately reflects the equilibrium and rate behavior of the resin compared to actual wastes. Batch tests and column tests will be used to compare equilibrium behaviors and rate behaviors, respectively. Second, the tests will assist in clarifying the negative interactions between the actual waste and the ion exchange resin, which cannot be effectively tested with simulant. Such interactions include organic fouling of the resin and salt precipitation in the column. These effects may affect the shape of the column breakthrough curve. The reduction in column size also may change the shape of the curve, making the individual effects even more difficult to sort out. To simplify the evaluation, the changes due to column size must be either understood or eliminated. This report describes the determination of the column size for actual waste testing that best minimizes the effect of scale-down. This evaluation will provide a theoretical basis for the dimensions of the column. Experimental testing is still required before the final decision can be made. This evaluation will be confined to the study of CS-100 and R-F resins with NCAW simulant and to a limited extent DSSF waste simulant. Only the cesium loading phase has been considered

  16. Vitrification of cesium-contaminated organic ion exchange resin

    Sargent, T.N. Jr. [Clemson Univ., SC (United States)

    1994-08-01

    Vitrification has been declared by the Environmental Protection Agency (USEPA) as the Best Demonstrated Available Technology (BDAT) for the permanent disposal of high-level radioactive waste. Savannah River Site currently uses a sodium tetraphenylborate (NaTPB) precipitation process to remove Cs-137 from a wastewater solution created from the processing of nuclear fuel. This process has several disadvantages such as the formation of a benzene waste stream. It has been proposed to replace the precipitation process with an ion exchange process using a new resorcinol-formaldehyde resin developed by Savannah River Technical Center (SRTC). Preliminary tests, however, showed that problems such as crust formation and a reduced final glass wasteform exist when the resin is placed in the melter environment. The newly developed stirred melter could be capable of overcoming these problems. This research explored the operational feasibility of using the stirred tank melter to vitrify an organic ion exchange resin. Preliminary tests included crucible studies to determine the reducing potential of the resin and the extent of oxygen consuming reactions and oxygen transfer tests to approximate the extent of oxygen transfer into the molten glass using an impeller and a combination of the impeller and an external oxygen transfer system. These preliminary studies were used as a basis for the final test which was using the stirred tank melter to vitrify nonradioactive cesium loaded organic ion exchange resin. Results from this test included a cesium mass balance, a characterization of the semi-volatile organic compounds present in the off gas as products of incomplete combustion (PIC), a qualitative analysis of other volatile metals, and observations relating to the effect the resin had on the final redox state of the glass.

  17. Treatment of spent ion-exchange resins for disposal

    Ion-exchange resins are used in CANDU-PHW nuclear power stations to purify heavy water in the primary heat transport (PHT) and moderator systems. Two techniques for conditioning spent ion-exchange resins for disposal have been evaluated: direct immobilization, and incineration combined with immobilization of the ash and scrubbed off-gases. When ion-exchange resins were immobilized directly, no volume reductions were obtained at the various resin-to-matrix weight ratios attempted. Volumes of bitumen and glass products were equal to the volumes of untreated resin while the volumes of cement and polyester products were two and three times larger. While incinerating the resin is an extra processing step, high reductions in volume result. Bitumen and glass product volumes were six times smaller than the volumes of untreated resin while cement and polyster product volumes were about half the volume of untreated resin. Since the releases of Cs-137 were about ten times lower for products made by direct immobilization, PHT resins, which have high concentrations of Cs-137, should be immobilized directly. Moderator resins which have high concentrations of C-14 should be incinerated and the ash- and C-14-contaminated scrubbing solutions should be immobilized. By pretreating such resins with calcium chloride, the C-14 present on resin could be released at temperatures below the ignition temperature of the resin. This technique reduces the amount of inactive carbon dioxide that must be scrubbed to trap the C-14. The releases of C-14 from immobilized barium hydroxide scrubbing solution were the same as releases from immobilized resin

  18. MMI splitter by ion exchange on K9

    Yuan, Jing; Luo, Fengguang; Cao, Mingcui; Chen, Wenmin

    2005-11-01

    A wavelength 0.85μm-based optical power splitter designed with Multi Mode Interference (MMI) by ion exchange on K9 glass was introduced. The waveguide material is K9 glass made in China and formed by K +-Na + pure melt salt ion exchange method. The grade index profile of planar ion-exchanged waveguide on K9 was studied and accorded with erfc function through compare of experimental and theoretic index profiles. The fabrication process of planar ionexchanged waveguide device was described. The basic theory of 1×8 MMI optical power splitter was illuminated by using guided-model propagation analysis. The working wavelength is 0.85μm, and the structure parameters of 1×8 MMI splitter were designed. The core pitch on this chip is chosen as 250μm to take the fiber connections into account, and the typical cladding diameter of optical fibers as 125μm. The critical parameters in the fabrication of the MMI power splitter are the multimode section width and length. In general the key performance specifications of the optical power splitter are insertion loss and uniformity. The output performances and the refractive index change's influence of the device were simulated by Bear Propagation Method (BPM). The uniformity was 0.93×10 -2dB, the average insertion loss was 9.12dB, and the maximal insertion loss was 9.14dB. The result shows that the advantages of the method include low loss, ease of fabrication, and low material cost.

  19. Ion Exchange Testing with SRF Resin FY2012

    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.

  20. Vitrification of cesium-contaminated organic ion exchange resin

    Vitrification has been declared by the Environmental Protection Agency (USEPA) as the Best Demonstrated Available Technology (BDAT) for the permanent disposal of high-level radioactive waste. Savannah River Site currently uses a sodium tetraphenylborate (NaTPB) precipitation process to remove Cs-137 from a wastewater solution created from the processing of nuclear fuel. This process has several disadvantages such as the formation of a benzene waste stream. It has been proposed to replace the precipitation process with an ion exchange process using a new resorcinol-formaldehyde resin developed by Savannah River Technical Center (SRTC). Preliminary tests, however, showed that problems such as crust formation and a reduced final glass wasteform exist when the resin is placed in the melter environment. The newly developed stirred melter could be capable of overcoming these problems. This research explored the operational feasibility of using the stirred tank melter to vitrify an organic ion exchange resin. Preliminary tests included crucible studies to determine the reducing potential of the resin and the extent of oxygen consuming reactions and oxygen transfer tests to approximate the extent of oxygen transfer into the molten glass using an impeller and a combination of the impeller and an external oxygen transfer system. These preliminary studies were used as a basis for the final test which was using the stirred tank melter to vitrify nonradioactive cesium loaded organic ion exchange resin. Results from this test included a cesium mass balance, a characterization of the semi-volatile organic compounds present in the off gas as products of incomplete combustion (PIC), a qualitative analysis of other volatile metals, and observations relating to the effect the resin had on the final redox state of the glass

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

    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.

  2. Diffusion of radiocesium in natural and synthetic ion exchangers

    Sorption of radiocesium on natural zeolites from Zaloshka gorica has been studied at different conditions and compared with that on Dowex 50 strongly acidic ion exchanger. The diffusion coefficients of cesium in the system Dowex-solution and zeolite-water were determined. The energy of activation for the diffusion found is 5.5 in first case and 13.6 kcal/mole in the second. The concentration profiles for the diffusion of cesium from a layer at different times are given. (author)

  3. Ion exchange of ammonium in natural and synthesized zeolites

    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 NH4+ 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 NH4+ entering the sodium form of the three materials was Na-clinoptilolite > Na-Y > Na-P, as indicated by values of ΔGo. The results demonstrated that the Si/Al molar ratio of zeolites determined the selectivity for NH4+

  4. Low temperature plasma incineration of radioactive ion-exchange resin

    The results of the incineration studies of radioactive ion-exchange resin in an oxygen plasma atmosphere at pressures 20...50 mbar are presented. The plasma is generated using a 27.12 MHz radio frequency (RF) generator. The chamber temperature during the incineration varies between 100...140 deg C depending on the oxygen pressure in the chamber. The virtue of the low-temperature incineration is that the radioactive substances remain in the solid ash. The average retention of 60Co and 137Cs in the incineration chamber was about 94 %. The retention of 99mTc was in the average 77 % and of 131I about 70 %. The results indicate that, within the limit of the measurement accuracy, practically all Co and Cs remains in the chamber and can be recovered and further conditioned with the ash. The rest of technetium and iodine can be easily recovered on any cooled surface right after the incineration chamber. The mass reduction achievable with this method is 95 %. The ion-exchange resins in use at the Loviisa NPP were used as test samples. The activity retention and ashing experiments were made with a 1:1 mixture of granular anion and cation resin. The same kind of mixture is used for the primary water purification at the Loviisa NPP. The test resin was labelled with 60Co, 137Cs, 99mTc and 131I. Also spent Loviisa NPP resin was incinerated. The VVER-440 reactors of the Loviisa NPP use boric acid to control the reactivity of the core. The boric acid in the resin presents an extra cumber in the incineration process tending to prevent the oxygen plasma from getting into contact with the resin. The results with the granulated spent Loviisa NPP resin were drastically inferior to the results with the labelled test resin. The average unburnt residual mass was about 20 %. By prior crushing of the resin equal incineration results could be achieved with the test resin and with the spent Loviisa NPP resin. The low-temperature plasma incineration of radioactive ion-exchange resins presents

  5. Immobilisation of ion exchange resins in cement: final report

    The removal of activity from spent decontaminating solutions eg LOMI can be achieved using organic ion exchange resins. These resins can be successfully immobilised in cement based matrices. The optimum cement system contained 10% Ordinary Portland Cement 84% gg Blast Furnace Slag, 6% Microsilica with a water cement ratio of 0.5 and a dry resin loading of 36% with respect to total weight. This information was successfully scaled up to 200 litres giving a product with acceptable compressive strength, dimensional stability and elastic modulus. Storage of samples under water appears to have no detrimental effects on the product's properties. (author)

  6. Processing of residual gold (III) solutions via ion exchange

    Alguacil, Francisco José; Adeva, Paloma; Alonso Gámez, Manuel

    2005-01-01

    The processing of gold (III)-hydrochloric acid solutions by the anionic ion exchange Lewatit MP-64_resin has been investigated. The influence of several variables such as the temperature, 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 gold (III) by Lewatit MP-64_shows that either the film-diffusion and the particle-diffusion models fit the adsorption pr...

  7. Ion-exchange resin separation applied to activation analysis (1963)

    The separation techniques based on ion-exchange resins have been used, in this study, for carrying out activation analyses on about thirty impurities. A separation process has been developed so as to standardise these analyses and to render them execution a matter of routine. The reparation yields obtained are excellent and make it possible to carry out analyses on samples having a large activation cross-section ween working inside a reinforced fume-cupboard. This technique has been applied to the analysis of impurities in tantalum, iron, gallium, germanium, terphenyl, and tungsten. The extension of this process to other impurities and to other matrices is now being studied. (authors)

  8. Optimizing the management of spent ion exchange resin

    Safety treatment,conditioning and disposal of spent ion exchange resin (SR) from nuclear facilities is a hot topic. The SR features, various treatment and conditioning methods, such as filling into the high integrity container after drying and dewatering, elution, hot compaction, biodegradation, incineration, wet oxidation, bituminization and vitrification are described in this paper. Especially, the cementation is expounded in detail. The swelling mechanism of cementlined spent resins and preventative measures are discussed. It is pointed out that the cementation formulation has to be given more attention and the key point is to comply with disposal requirements. Finally, comments and suggestions for optimizing the management of spent resins are addressed

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

    Alguacil, F. J.

    1998-01-01

    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 th...

  10. Esterification of levulinic acid with butanol over ion exchange resins

    Tejero Iborra, M. Àngels; Ramírez Rangel, Eliana; Fité Piquer, Carles; Tejero Salvador, Xavier; Cunill García, Fidel

    2016-01-01

    Alkyl levulinates are biobased chemicals with a great number of applications and great biofuel potential for blending to conventional diesel or gasoline. The present work focuses on the liquid-phase synthesis of butyl levulinate (BL) by esterification of levulinic acid (LA) with 1-butanol (BuOH) using a set of acidic ion-exchange resins. Experiments were performed at 80 °C and 2.5 MPa in a batch reactor by using an initial molar ratio AL/BuOH of 1/3 and a catalyst loading of 0.8%. It has been...

  11. Ion exchange separation and production of metallic tachnetium

    The ion-exchange method of technetium concentration on resins permits to separate it from radioruthenium which transforms into the cation form rather completely at pH 3. It is established that increase of nitric acid concentration in the solution brings about monotonous decrease of pertechnetate-ion distribution coefficient. It is found that selectiveness of resins to [TcO4]- is conditioned by properties of resins, [TcO4]- structure, high degree of hydration. Technetium desorption from resin is performed by sodium nitrate. After deep purification by extraction from fission products and large content of technetium salts is transformed into metallic state by thermal decomposition of pertechnates of organic substances in inert atmosphere

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

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

  13. Ion exchange characteristics of decontaminating formulations as suited to nuclear reactors

    Ion exchangers are employed in the chemical decontamination process for metal ion removal, regeneration of decontaminants and removal of the formulation chemicals from the coolant. Decontaminants can interact with both strong base and acid ion exchangers leading to a loss of the required chemical concentrations in the liquid phase for effectively decontaminating the radioactive deposits. In order to understand these interactions, adsorption of EDTA, HEEDTA, DTPA and NTA on strong cation exchanger was studied under dynamic conditions. Selective retention of decontaminant formulation on anion exchanger, pickup of metals by preequilibrated anion exchanger and the effect of temperature on the cation exchanger were studied. (author)

  14. The selectivity of zirconium phosphate for caesium in electrochemical ion exchange

    The properties of amorphous zirconium phosphate are investigated as an inorganic ion exchanger for use in liquid waste treatment by electrochemical ion exchange. Experiments to determine and increase the selectivity for caesium exchange over sodium are discussed, including various pulsed waveforms and studies with rotating membranes. Automation of a sampling system with pH and atomic absorption measurements is described. (author)

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

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

    2011-06-01

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

  16. Study of Aging ion exchange membranes used in separation processes

    Presently, the most important application of ion exchange membranes (IEM) is the electrodialysis. This technique consists of a membrane separation using a series of anion exchange membranes alternately and cations, often used for the desalination of brackish water. These membranes are confronted with problems of aging. Indeed, the more they are used more physical and chemical properties will change. A comparative study of the behavior of both EMI and new but the same treatment is carried out by measuring a magnitude transfer characteristic: ion permeability. Ionic permeability is a physical quantity can have an idea about the selectivity of the membrane towards the charged species and the porosityof the membrane. It is a transport of ions (cations + anions) through the membrane. Thus, determining the ion permeability is to determine the diffusion flux of a strong electrolyte through a membrane separating two compartments (one containing electrolytes and other water initially ultrapure who will gradually electrolyte through the membrane). The measurement technique used is that by conductimetric detection because of the ease of its implementation and its accuracy. Thus, the variation of the concentration of the electrolyte is continuously monitored by measuring the conductivity of the solution diluted with time. The curves s = f (t) MEA and MEC new and used varying concentration of the electrolyte membranes show that let in less waste of strong electrolyte (NaCl and HCl) than new ones. This can be explained by: - The functional sites are combined with polyvalent ions present even in trace amounts in the solution process and become inactive. The membrane loses its hydrophilic character and turns into a film almost hydrophobic. - The chemical attacks and electrodialysis operations have degraded and eliminated much of the fixed sites leading to the same effects on the hydrophilic membrane. - These two assumptions have been reinforced by the extent of exchange capacities

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

    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.

  18. Evaluation of Ion Exchange Materials in K Basin Floor Sludge and Potential Solvents for PCB Extraction from Ion Exchange Materials

    Approximately 73 m3 of heterogeneous solid material, ''sludge,'' (upper bound estimate, Packer 1997) have accumulated at the bottom of the K Basins in the 100 K Area of the Hanford Site. This sludge is a mixture of spent fuel element corrosion products, ion exchange materials (organic and inorganic), graphite-based gasket materials, iron and aluminum metal corrosion products, sand, and debris (Makenas et al. 1996, 1997). In addition, small amounts of polychlorinated biphenyls (PCBs) have been found. These small amounts are significant from a regulatory standpoint. Ultimately, it is planned to transfer the K Basins sludge to the Hanford double shell tanks (DSTs). Chemical pretreatment is required to address criticality issues and the destruction or removal of PCBs before the K Basin sludge can be transferred to the DSTs. Eleven technologies have been evaluated (Papp 1997) as potential pretreatment methods. Based on the evaluations and engineering studies and limited testing, Fluor Daniel Hanford recommended solvent washing of the K Basin sludge, followed by nitric acid dissolution and, potentially, peroxide addition (FDH 1997). The solvent washing (extraction) and peroxide addition would be used to facilitate PCB removal and destruction. Following solvent extraction, the PCBs could be distilled and concentrated for disposal as a low-level waste. The purpose of the work reported here was to continue investigating solvent extraction, first by better identifying the ion exchange materials in the actual sludge samples and then evaluating various solvents for removing the PCBs or possibly dissolving the resins. This report documents some of the process knowledge on ion exchange materials used and spilled in the K Basins and describes the materials identified from wet sieving KE Basin floor and canister sludge and the results of other analyses. Several photographs are included to compare materials and illustrate material behavior. A summary of previous tests on solvent

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

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

    2014-01-01

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

  20. Incorporation of radioactive spent ion exchange resins in plastics

    Experiments were undertaken on the incorporation in plastics - polyethylene in particular - of radioactive spent ion exchange resins produced in nuclear power plants. The resulting polyethylene products burdened with radioactive resin were tested to ascertain the properties considered important for radioactive waste management. The items chosen for testing were mechanical strength, leachability of radionuclide and radiation resistance. Polyethylene products burdened with 50 wt % of resin were found to possess an impact strength of 10 kg.cm/cm and a compressive strength of 300 kg/cm2, which values do not indicate any appreciable decrease in mechanical strength compared with polyethylene unburdened with resin. The leaching rate of 137Cs from the resin-burdened polyethylene product was very small - only 0.1% leached out in one year. In respect of decomposition by radiation, the amount of gases evolving upon absorbing a dose of 109 rad was 10 ml/g. The effect of radiation on the mechanical strength was also studied. It is concluded from above results that solidification of radioactive spent ion exchange resin by incorporation in plastics is one of the best methods devised so far for treating spent resins. (auth.)

  1. Low-level liquid waste decontamination by ion exchange

    Improved processes are being developed to treat contaminated liquid wastes that have been and continue to be generated at Oak Ridge National Laboratory. Both inorganic and organic ion-exchange methods have given promising results. Nickel and cobalt hexacyanoferrate(Il) compounds are extremely selective for Cs removal, with distribution coefficients in excess of 106 and remarkable insensitivity to competition from Na and K. They tend to lose effectiveness at pH > - 11, but some formulations are useful for limited periods of time up to pH - 13. Sodium titanate is selective for Sr removal at high pH. The separations are so efficient that simple, batch processes can yield large DFs while generating small volumes of solid waste. A resorcinol-based resin developed at the Savannah River Site gave superior Cs removal compared with other organic ion exchangers; the distribution coefficient was limited primarily by competition from K and nearly independent of Na. The optimum pH was - 12.5. It was much less effective for Sr removal, which was limited by competition from Na. 8 refs., 4 figs., 9 tabs

  2. Ion exchangers in radioactive waste management: Natural Iranian zeolites

    Five samples of natural zeolites from different parts of Iran were chosen for this study. In order to characterize and determine their structures, X-ray diffraction and infrared spectrometry were carried out for each sample. The selective absorption properties of each zeolite were found by calculating the distribution coefficient (K d) of various simulated wastes which were prepared by spiking the radionuclides with 131I, 99Mo, 153Sm, 140La and 147Nd. All the zeolite samples used in this study had extremely high absorption value towards 140La; clinoptolite from Mianeh and analsite from Ghalehkhargoshi showed good absorption for 147Nd; clinoptolite from Semnan and clinoptolite from Firozkoh showed high absorption for 153Sm; mesolite from Arababad Tabas showed good absorption for 99Mo; and finally mesolite from Arababad Tabas, clinoptolite from Semnan and clinoptolite from Firozkoh could be used to selectively absorb 131I from the stimulated waste which was prepared. The natural zeolites chosen for these studies show a similar pattern to those synthetic ion exchangers in the literature and in some cases an extremely high selectivity towards certain radioactive elements. Hence the binary separation of radioactive elements could easily be carried out. Furthermore, these zeolites, which are naturally occurring ion exchangers, are viable economically and extremely useful alternatives in this industry

  3. Treatment of geothermal wastewater by ion exchange method

    Beker, U.G. [Istanbul Technical University (Turkey). Chemical Engineering Dept.

    1999-04-01

    The west part of Turkey has great potential for geothermal energy resources. The exploitation of this potential in the Denizli-Kizildere geothermal energy region depends on the removal of its high boron content since waste brine is discharged into the nearby River Buyuk Menderes. This river is an important source of agricultural irrigation so consideration must be given to the amount and quality of the added geothermal waste water. A study is made of boron removal from Kizildere/Turkey geothermal wastewater using ion exchange resin. The use of ion exchange resin for the removal of boron from wastewaters requires expensive regeneration steps. A three stage acid regeneration process has been investigated to find the optimal operational conditions for minimizing the regenerant consumption. Boron removal after three stage acid regeneration with 5% H{sub 2}SO{sub 4} is possible since the wastewater of the Kizildere geothermal field has enough buffering capacity to neutralize the released acid from the resin. (author)

  4. Ion-exchange equilibria and diffusion in engineered backfill

    Engineered backfill can add confidence to confinement times of high-level nuclear waste stored in geologic media. This paper discusses the design and operation of a unique radial-flow diffusion cell to determine ion migration rates in backfill material under realistic repository conditions. New experimental results were reported for diffusion of CsCl in a background of NaCl into compacted bentonite and bentonite/quartz mixtures. Representation of the measured diffusion rates by the traditional, homogeneous porous-medium model significantly underestimates cesium penetration distances into the backfill. Surface diffusion is suggested as an additional mechanism by which cations transport in swollen montmorillonite; the surface diffusion coefficients for cesium is determined to be approximately 10-7 cm2/s. An electrostatic site-binding model is developed for ion-exchange equilibria on montmorillonite clay. The effect of pH, ionic strength, and specific adsorption are evaluated and compared favorably to new, experimental exchange isotherms measured on disaggregated clay. The electrostatic site-binding model permits a prediction of the influence of backfill compaction on K/sub d/ values. We find that for strongly adsorbing cations, compactions has little effect. However, anions exhibit significant Donnan exclusion with clay compaction. 40 references, 12 figures

  5. Plasma arc pyrolysis of radioactive ion exchange resin

    This paper reports on two ion exchange resins (IRN 77 and IRN 78) which were pyrolysed in a plasma-arc furnace. Both continuous and batch tests were performed. Volume reduction ratios of 10 to 1 and 10 to 3.5 were achieved for IRN 78 and IRN 77 respectively. The product of the resin pyrolysis was a char which contained the radioactive elements such as cobalt. The off-gases consisted of mainly hydrogen and carbon monoxide. There was a relatively small amount of dust in the off-gases. At the present time radioactive ion exchange resign is being kept in storage. The volume of this waste is increasing and it is important that the volume be reduce. The volume reduction ratio should be of the order of ten-to-one. Also, it is required that the radioactive elements can be collected or fixed in a form which could easily be disposed of. Plasma arc treatment offers considerable potential for the processing of the waste

  6. Low-level liquid waste decontamination by ion exchange

    Improved processes are being developed to treat contaminated liquid wastes that have been and continue to be generated at Oak Ridge National Laboratory. Both inorganic and organic ion-exchange methods have given promising results. Nickel and cobalt hexacyanoferrate(2) compounds are extremely selective for cesium removal, with distribution coefficients in excess of 106 and remarkable insensitivity to competition from sodium and potassium. They tend to lose effectiveness at pH > ∼11, but some formulations are useful for limited periods of time up to pH ∼13. Sodium titanate is selective for strontium removal at high pH. The separations are so efficient that simple batch processes can yield large decontamination factors while generating small volumes of solid waste. A resorcinol-based resin developed at the Savannah River Site gave superior cesium removal, compared with other organic ion exchangers; the distribution coefficient was limited primarily by competition from potassium and was nearly independent of sodium. The optimum pH was ∼12.5. It was much less effective for strontium removal, which was limited by competition from sodium. 8 refs., 6 figs., 9 tabs

  7. Isotope exchange by Ion Cyclotron Wall Conditioning on JET

    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.

  8. Study of the Fixation and Migration of Radioactive Cations in a Natural Ion Exchanger

    With a view to utilizing lignite as a natural ion exchanger in the treatment of radioactive waste, a study was made of its physical and physico-chemical properties with reference to ion exchange. The distribution of Sr90 and Cs137 ions in the presence of Ca, Na and H was first examined and the equilibrium constants calculated. The kinetics and fixation of ions were then studied, and various parameters required for the calculation of ion-exchange beds were established. Study of the complex phenomenon of radioactive ion migration in the soil was started by the separate investigation of each component ionic equilibrium. (author)

  9. Enhanced DOC removal using anion and cation ion exchange resins.

    Arias-Paic, Miguel; Cawley, Kaelin M; Byg, Steve; Rosario-Ortiz, Fernando L

    2016-01-01

    Hardness and DOC removal in a single ion exchange unit operation allows for less infrastructure, is advantageous for process operation and depending on the water source, could enhance anion exchange resin removal of dissolved organic carbon (DOC). Simultaneous application of cationic (Plus) and anionic (MIEX) ion exchange resin in a single contact vessel was tested at pilot and bench scales, under multiple regeneration cycles. Hardness removal correlated with theoretical predictions; where measured hardness was between 88 and 98% of the predicted value. Comparing bench scale DOC removal of solely treating water with MIEX compared to Plus and MIEX treated water showed an enhanced DOC removal, where removal was increased from 0.5 to 1.25 mg/L for the simultaneous resin application compared to solely applying MIEX resin. A full scale MIEX treatment plant (14.5 MGD) reduced raw water DOC from 13.7 mg/L to 4.90 mg/L in the treated effluent at a bed volume (BV) treatment rate of 800, where a parallel operation of a simultaneous MIEX and Plus resin pilot (10 gpm) measured effluent DOC concentrations of no greater than 3.4 mg/L, even at bed volumes of treatment 37.5% greater than the full scale plant. MIEX effluent compared to simultaneous Plus and MIEX effluent resulted in differences in fluorescence intensity that correlated to decreases in DOC concentration. The simultaneous treatment of Plus and MIEX resin produced water with predominantly microbial character, indicating the enhanced DOC removal was principally due to increased removal of terrestrially derived organic matter. The addition of Plus resin to a process train with MIEX resin allows for one treatment process to remove both DOC and hardness, where a single brine waste stream can be sent to sewer at a full-scale plant, completely removing lime chemical addition and sludge waste disposal for precipitative softening processes. PMID:26624231

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

    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.