Note: This page contains sample records for the topic ratio ion exchange from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

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

SciTech Connect

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

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

2007-09-27

2

Ion Exchange  

Microsoft Academic Search

\\u000a Several processes can be used to attract soluble ions from the liquid phase to the solid phase and among these is ion exchange,\\u000a which is arguably the most widely used in the water treatment industry for this purpose (1-4). Ion exchange (IX) provides\\u000a a means for transferring one or more ionic species from one liquid phase to another via intermediate

J. Paul Chen; Lei Yang; Wun-Jern Ng; Lawrence K. Wang; Sook-Leng Thong

3

Data of Ion Exchange.  

National Technical Information Service (NTIS)

Behavior of ion exchange of several elements are compiled as 30 figures in the sequence of periodic system. Exchangers are Dowex, Diaion and inorganic ion exchangers. Data of adsorption on charcoal and silica gel are also given. (Atomindex citation 09:367...

E. Akatsu

1977-01-01

4

Ardennes Fractional Exchange Ratio Research.  

National Technical Information Service (NTIS)

The US Army Concepts Analysis Agency (CAA) requires guidelines on use and computation of the combat measure of effectiveness (MOE) denote as the fractional exchange ratio (FER). The Ardennes Campaign Simulation Data Base (ACSDB) derived from historical ar...

W. Bauman

1997-01-01

5

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

Microsoft Academic Search

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

John W. Valley; Colin M. Graham

1991-01-01

6

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

PubMed

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

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

2011-07-28

7

Ion exchange phenomena  

SciTech Connect

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).

Bourg, I.C.; Sposito, G.

2011-05-01

8

Ion Exchange Membrane Processes  

SciTech Connect

Techniques were developed, and promising preliminary tests were completed in an exploratory study of the applicability of ion exchange membrane processes to such chemical operations as the separation of plutonium from uranium, the separation of americium from curium, the isolation of individual rare earths, the removal of strontium from process waste streams. This report discusses results of those tests.

Wallace, R.M.

2002-10-30

9

Pharmaceutical Applications of Ion-Exchange Resins  

NASA Astrophysics Data System (ADS)

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

Elder, David P.

2005-04-01

10

Ion exchange technology assessment report  

SciTech Connect

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

Duhn, E.F.

1992-01-01

11

Ion exchange technology assessment report  

SciTech Connect

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

Duhn, E.F.

1992-12-31

12

Ion Exchange Properties of New Crystalline Inorganic Ion Exchangers.  

National Technical Information Service (NTIS)

Micro crystals of both alpha-FeOOH and mono-clinic zirconia (ZrO2) were prepared. They possess weak acidic or weak basic or amphoteric ion exchange behavior. Using new pH titration techniques, detailed studies were made on these exchangers. They were show...

H. U. Rehman

1987-01-01

13

Cesium-specific phenolic ion exchange resin  

DOEpatents

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

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

1995-08-15

14

Electrically Switched Cesium Ion Exchange  

SciTech Connect

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

JPH Sukamto; ML Lilga; RK Orth

1998-10-23

15

Ion Exchange Chromatography  

NSDL National Science Digital Library

This website contains an ion chromatography simulator that can be run online or can be downloaded. The simulator focuses on separations of proteins using Ion Chromatography. Also included is linked reference information, an example of a homework assignment using the simulator, and some information on protein structures.

2011-05-23

16

Phosphonic acid based ion exchange resins  

DOEpatents

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

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1996-01-01

17

Phosphonic acid based ion exchange resins  

DOEpatents

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

Horwitz, E. Philip (Naperville, IL); Alexandratos, Spiro D. (Knoxville, TN); Gatrone, Ralph C. (Naperville, IL); Chiarizia, Ronato (Oak Park, IL)

1994-01-01

18

DIVALENT ION EXCHANGE WITH ALKALI  

SciTech Connect

Exchange of hardness ions is important in enhanced oil recovery with chemical additives. In both micellar-polymer and caustic flooding processes, multivalent ions released from rock surfaces can interact with anionic surfactants, rendering them preferentially oil soluble and/or insoluble in water. Because hardness cations are sparingly soluble and precipitate in alkaline solutions, such solutions may be more efficient as surfactant flood preflushes than are softened brines. Multivalent ion precipitation may also occur in alkaline waterflooding. To permit design of such processes, this paper presents a chromatographic theory for simultaneous ion exchange with precipitation of divalent ions. Theoretical effluent histories and concentration profiles are presented for the cases of finite pulses and continuous injection of hydroxide ions into linear cores. Complete capture of the insoluble salt particles is assumed. Results are given for the case of instantaneous equilibration of the solution with the precipitate, as well for the case of complete nonequilibrium, in which the solid precipitate does not redissolve. The efficiency of alklaine preflushing is shown to depend on the exchange isotherm, initial divalent loading of the rock, injected pH and salinity, the solubility product of the precipitated salt, and pulse size. The effect of slug size on complete equilibrium removal of hardness ions is reduced efficiency with increasing size until a critical volume approximating continuous injection is reached. Increasing injected pH and salinity provides a more favorable response. Experimental data for Berea sandstone and an argillaceous sand compare favorably with the proposed theory.

Bunge, A.L.; Klein, G.; Radke, C.J.

1980-05-01

19

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

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

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

1997-04-08

20

Ion exchange of mixed-alkali glasses  

NASA Astrophysics Data System (ADS)

The effect of mixed-alkali composition on ion-exchange strengthening of glasses was studied. The partial substitution of potassium for sodium in a soda-lime-silicate host glass was found to increase the potassium penetration depth during ion exchange in molten potassium nitrate. A host glass with an alkali ratio of K:Na = 0.27 showed a 13% increase in potassium penetration depth for an eight-hour exchange at 510°C, as compared to the base soda-lime-silicate glass. However, the substitution of potassium caused a decrease in the strain point which resulted in appreciable stress relaxation during ion-exchange strengthening. Hence less compressive stress developed. This decrease was addressed by a partial substitution of alumina for silica in the host glass. The substitution of 3 mol% alumina increased the strain point ? 12°C and resulted in a decrease in the stress relaxation of the host glass. For high-temperature ion-exchange treatments, the addition of alumina was found to increase the potassium penetration depth of the mixed-alkali glasses. As a result of the increased potassium penetration depth and the decreased stress relaxation, the mixed-alkali glasses were found to have an increased resistance to abrasion by SiC, as measured by breaking strength.

Mattos, Louis, Jr.

1999-11-01

21

Ion-Exchanged Diffractive Optical Elements.  

National Technical Information Service (NTIS)

The research presented in this dissertation involves a new fabrication method for diffractive elements, namely, ion exchange in glass. Enhancements in the design of ion-exchanged diffractive elements in waveguides are also presented. Some introductory bac...

R. P. Salmio

1998-01-01

22

Ion Exchange Waveguides and Methods Fabrication.  

National Technical Information Service (NTIS)

A method for fabricating ion exchange waveguides, such as lithium niobate or lithium tantalate waveguides in optical modulators and other optical waveguide devices, utilizes pressurized annealing to further diffuse and limit exchange of the ions and inclu...

L. J. Burrows

2004-01-01

23

Divalent ion exchange with alkali  

SciTech Connect

Exchange of hardness ions is important in EOR with chemical additives. In both micellar/polymer and caustic flooding processes, multivalent ions released from rock surfaces can interact with anionic surfactants, rendering them preferentially oil soluble and/or insoluble in water. Because hardness cations are sparingly soluble and precipitate in alkaline solutions, such solutions may be more efficient as surfactant-flood preflushes than are softened brines. Multivalent ion precipitation may also occur in alkaline waterflooding. To permit design of such processes, this paper presents a chromatographic theory for simultaneous ion exchange with precipitation of divalent ions. Theoretical effluent histories and concentration profiles are presented for the cases of finite pulses and continuous injection of hydroxide ions into linear cores. Complete capture of the insoluble salt particles is assumed. Results are given for the case of instantaneous equilibration of the solution with the precipitate, as well as for the case of complete nonequilibrium, in which the solid precipitate does not redissolve. The theoretical model, when applied to field conditions, predicts redissolution zones that have not been previously recognized because solution residence times in laboratory columns are too short.

Bunge, A.L.

1983-08-01

24

Pharmaceutical Applications of Ion-Exchange Resins  

Microsoft Academic Search

The historical uses of ion-exchange resins and a summary of the basic chemical principles involved in the ion-exchange process are discussed. Specific applications of ion-exchange resins are provided. The utility of these agents to stabilize drugs are evaluated. Commonly occurring chemical and physical incompatibilities are reviewed. Ion-exchange resins have found applicability as inactive pharmaceutical constituents, particularly as disintegrants (inactive tablet

David P. Elder

2005-01-01

25

225B ion exchange piping design documentation  

Microsoft Academic Search

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

Prather

1996-01-01

26

Pharmaceutical Applications of Ion-Exchange Resins  

ERIC Educational Resources Information Center

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

Elder, David

2005-01-01

27

Ion exchange purification of scandium  

DOEpatents

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

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

1990-10-23

28

Model Hydrophobic Ion Exchange Membrane  

PubMed Central

Two models of hydrophobic ion exchange membranes were examined theoretically with regard to the characteristics of cellulose acetate-nitrate membranes saturated with hydrophobic solvents. The first model, consisting of fixed negative sites dispersed in a homogeneous medium of low dielectric constant, was shown to be invalid for the experimental membranes. The second model, consisting of fixed negative sites in an aqueous channel surrounded by a medium of low dielectric constant, explains many properties of the cellulose acetate-nitrate hydrophobic membranes and was analyzed in some detail. Organic cations can enter the membranes through the hydrophobic phase as well as through the aqueous channels. The mechanism of counterion movement in such a model is assumed to consist of exchange of vacancies and or double-occupied sites positions. The presence of the medium of low dielectric constant around the aqueous channel increases the “self”-energy of the ions in the channel and the electrostatic interaction between a fixed site and a counterion in the membrane. Both these factors can account for the marked dependence of ion mobility in the aqueous channels on the dielectric constant of the surrounding medium. The model predicts membrane preference for monovalent counterions over divalent ones. ImagesFigure 3

Shohami, Esther; Ilani, Asher

1973-01-01

29

Divalent ion exchange with alkali  

SciTech Connect

In micellar polymer and alkaline floodings in order to increase the oil production of strata, Ca-cation(2) ions and Mg-cation(2) ions in the stratum water are placed in reaction with anionic surfacants (PAV), reducing the effectiveness of using these particular methods. To determine the capability of sedimenting the divalent ions in the form of salts with pumping of alkaline margins, a chromatographic theory of simultaneous ion exchange and salt sedimentation is proposed. Data are presented for the cases of pulsation and continuous pumping of OH-anion ions into cores and the results are cited for equilibrium of a solution with a sediment and for imbalance with which the sediment is not redisolved. A conclusion is drawn about the possibility of repeat solution of the sedimented salts in practice, which was not established in laboratory conditions. In predicting, the sedimentation of silicates should be considered, as well as the phenomena of dispersion. On the whole, the theoretical model agrees well with experimental results.

Bunge, A.L.; Radke, C.J.

1983-01-01

30

Ion exchange and protonation equilibria of an amphoteric ion-exchange resin in the presence of simple salt.  

PubMed

The influence of simple salts on the ion exchange and protonation equilibria of an amphoteric ion-exchange resin, which has strong base and weak acid moieties in a single functional group fixed onto the styrene-DVB matrix, has been investigated. Concentrations of ionic species in the amphoteric ion-exchange resin in equilibrium with various sodium salt solutions were estimated by (23)Na NMR spectroscopy. For the NaClO(4) system, the ratio of sodium ion concentration in the resin phase to that in the equilibrium solution was greater than 1 and increased with a decrease in the salt concentration. In contrast to an ordinary cation-exchange resin, the ion exchange behavior of Mg(2+) and Ca(2+) on the amphoteric ion-exchange resin showed a marked dependence on the kinds of salts: the distribution coefficients for the NaCl system were independent of the salt concentration, while the log D vs. log[Na(+)] plots for the NaClO(4) system showed linear relationships with slopes being neither -2 nor 0. Apparent protonation constants of the carboxylate in the functional group of the resin in equilibrium with NaClO(4) solutions were greater than those with NaCl solutions. The ion exchange and protonation properties of the amphoteric ion-exchange resin were elucidated on the basis of the information about the salt concentrations in the resin phase estimated by the NMR method. PMID:18781023

Miyazaki, Yoshinobu; Qu, Hui; Konaka, Junko

2008-09-01

31

Solidification of ion exchange resin wastes  

SciTech Connect

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

Not Available

1982-08-01

32

Using Ion Exchange Chromatography to Separate Proteins  

NSDL National Science Digital Library

This activity website, hosted by the National Health Museum Activities Exchange, explores protein purification using ion chromatography. Students will separate a positively charged lysozyme from a negatively charged albumin at a neutral pH using ion exchange chromatography. The site includes information for the teacher, instructions and follow-up questions for students, and a list of supplies.

Daugherty, Ellyn A.; Exchange, Access E.

33

Using Ion Exchange Chromatography to Separate Proteins  

NSDL National Science Digital Library

This activity website, hosted by the National Health Museum Activities Exchange, explores protein purification using ion chromatography. Students will separate a positively charged lysozyme from a negatively charged albumin at a neutral pH using ion exchange chromatography. The site includes information for the teacher, instructions and follow-up questions for students, and a list of supplies.

Daugherty, Ellyn A.

2010-02-02

34

Titania bound sodium titanate ion exchanger  

DOEpatents

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

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

1999-03-23

35

Ion Exchange and Adsorption of Inorganic Contaminants  

EPA Science Inventory

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

36

Ion exchange in the nuclear industry  

SciTech Connect

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.

Bibler, J.P.

1990-12-31

37

Ion exchange in the nuclear industry  

SciTech Connect

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.

Bibler, J.P.

1990-01-01

38

Ion Exchange Membrane Influence on Ohmic Resistance  

Technology Transfer Automated Retrieval System (TEKTRAN)

Selection of the proper ion exchange membrane can have a significant influence on bioelectrochemical system (BES) power densities. Because ions move across the membrane to achieve electroneutrality, the ion transport resistance (ohmic loss) needs to be minimized to increase power densities. Ohmic ...

39

Trivalent Ion Exchange in Beta' Alumina.  

National Technical Information Service (NTIS)

Ion exchange techniques were used to substitute trivalent cations for the sodium ions present in sodium beta alumina single crystals. Complete replacement was achieved using Gd3+, Nd3+, and Eu3+ ions in molten salts. The conductivity of Gd3+ beta alumina ...

B. Dunn G. C. Farrington

1984-01-01

40

10 CFR Appendix E to Part 110 - Illustrative List of Chemical Exchange or Ion Exchange Enrichment Plant Equipment and Components...  

Code of Federal Regulations, 2010 CFR

...Illustrative List of Chemical Exchange or Ion Exchange Enrichment Plant Equipment and...Illustrative List of Chemical Exchange or Ion Exchange Enrichment Plant Equipment and...liquid-liquid chemical exchange and solid-liquid ion exchange. A. In the...

2009-01-01

41

Ion Exchange Analysis of Columbium Alloys.  

National Technical Information Service (NTIS)

An ion-exchange method developed at AMRA (see AD-653 767) was applied to the analysis of synthetic mixtures representing various columbium-base alloys. The alloying elements which were separated and determined include vanadium, zirconium, hafnium, titaniu...

T. A. Ferraro

1967-01-01

42

Composite ion exchangers: Prospective nuclear applications  

Microsoft Academic Search

Properties and applications of composite ion exchangers developed in this Institute are described. The new sorbents consist of a selective inorganic ion exchanger, e.g., hexacyanoferrate of transition metals or hydrated antimony pentoxide, firmly incorporated into a resin matrix, e.g., phenol-formaldehyde, of various shapes. The composites have proved to be effective adsorbents for radionuclides of cesium, sodium, francium, elements 104 and

J. Narbutt; A. Bilewicz; B. Barto?

1994-01-01

43

Ion Exchange Resins Transforming Drug Delivery Systems.  

PubMed

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

Gupta, Shweta; Parul; Sahoo, P K

2010-02-17

44

Influence of water hardness on removal of copper ions by ion-exchange-assisted electrodialysis  

Microsoft Academic Search

The organic ion exchangers (Dowex HCR-S, Dowex 50WX-2) and inorganic ion exchangers with phosphate functional groups (zirconium phosphates ZrP-1, ZrP-2) were studied as transport media for ion-exchange-assisted electrodialysis of diluted solutions containing Cu (II) ions. The ion-exchange and electric conductive properties of ion exchangers containing Cu(II) ions were studied. The most conductive exchangers were chosen. The adsorption data showed a

S. L Vasilyuk; T. V Maltseva; V. N Belyakov

2004-01-01

45

Ion-exchange studies with some complex ions on ion-exchange resins  

SciTech Connect

The ion exchange equilibria of Cr(NH{sub 3}){sub 6}{sup 3+}, Cr(NH{sub 3}){sub 5}Cl{sup 2+}, cis-Cr(en){sub 2}Cl{sub 2}{sup +}, trans-Cr(en){sub 2}(SCN){sub 2}{sup +}, Cr(H{sub 2}O){sub 6}{sup 3+} complex ions against La{sup 3+} ions were studied. The effect of the ionic charge, radius and composition of various chromium complex ions on the selectivity were discussed. The logarithms of the selectivity constants were plotted versus mole fraction of complex ions in the resin phase. Linear variations with negative slopes were observed in experiments except for the Cr(H{sub 2}O){sub 6}{sup 3+}-La{sup 3+} system. 17 refs., 5 figs.

Besirli, N. [Karadeniz Technical Univ., Trabzon (Turkey); Baysal, B.M. [Istanbul Technical Univ., Istanbul (Turkey)

1993-07-01

46

The electrochemical investigation of salts partition with ion exchange membranes.  

PubMed

The regenaration of acid and base from the solutions containing metallic salts was achieved by salt splitting method (SSM) using not only anion-exchange membranes (AEM) but also cation-exchange membrane (CEM). In these experiments, while the ion exchange membrane was anion-exchange membrane, acid solutions were used as an anolyte and different salts of potassium were used as a catholyte. In addition to these experiments, while the ion exchange membrane was cation-exchange membrane, base solutions were used as a catholyte and different salts of potassium were used as an anolyte. The effects of current density, initial concentrations of anolyte and catholyte solutions, the type of salt solution and the type of the ion-exchange membranes on the recovery ratio of bases and acids were investigated. The results of the experiments were investigated with the Statistical Package for Social Sciences (SPSS) program. The obtained results show that this technique can be used not only for recovering the acid and base wastes of industry but also for removing the impurities in order to obtain pure acids and bases in laboratory conditions. PMID:18417288

Ata, Nejla; Yazicigil, Zafer; Oztekin, Yasemin

2008-03-04

47

Ion Exchange Resins Transforming Drug Delivery Systems.  

PubMed

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

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

2010-05-24

48

Ion-exchanged waveguides: current status  

NASA Astrophysics Data System (ADS)

Integrated optical components based on ion-exchanged glass waveguides are finding applications in real systems. Recently, significant progress has occurred in the understanding of the ion-exchange process. It is now possible to model the thermal as well as electrical field enhanced diffusion with reasonable accuracy and to design ion-exchanged waveguides and devices with prespecified characteristics. This paper describes the theory of the ion-exchange process and explains the diffusion profile for Ag+-Na+ and K+- Na+ cation pairs used in BK7 glass for planar and 2-D (channel) waveguide fabrication. Following this, we present the latest results in modeling and fabrication of several devices based on single-mode channel waveguides. These include couplers, power dividers, MUX/DEMUX, and polarization splitters for applications in optical communications. Finally, we point out the latest trends and novel emerging applications of ion-exchanged waveguides, such as all optical switching, waveguide lasers and amplifiers, and integration of passive waveguides on glass with optoelectronic devices.

Srivastava, Ramakant; Ramaswamy, Ramu V.

1991-12-01

49

Ion exchange enrichment of uranium isotopes  

SciTech Connect

A process for the enrichment of one isotope in a mixture of uranium isotopes by passing a solution of the mixture in a solvent through an anion exchanger thereby forming on the anion exchanger a boundary (A) between a uranium adsorption zone and an adjacent reducing agent zone and/or a boundary (B) between a uranium adsorption zone and an adjacent oxidizing agent zone, the uranium adsorption zone advancing through the anion exchanger, effecting reduction at the boundary (A) and/or effecting oxidation at the boundary (B), thereby effecting enrichment adjacent said boundary, and separating a fraction enriched in one of said isotopes, which process comprises using as the solvent medium a composition comprising (A) a solvent having a dielectric constant of at least 80 at 20* C., (B) hydrochloric acid and (C) at least one of hydrobromic acid and sulfuric acid, the solvent medium having a hydrogen ion concentration of about 0.1 m/l to about 10 m/l, a total chlorine ion concentration of about 0.1 m/l to about 12 m/l, at least one of bromine and sulfate ion being present in about 0.01 m/l to about 10 m/l and the other being present in from zero up to 10 m/l, and passing the materials through the ion exchanger at a rate such that the migration velocity of the uranium adsorption zone through the ion exchanger is at least about 1 cm per minute.

Miyake, T.; Onitsuka, H.; Takeda, K.

1983-01-11

50

Ion exchange in a semifluidized bed  

SciTech Connect

Removal of copper ions from electroplating wastewater by ion exchange in a liquid-solid semifluidized bed is studied. The column diameter and height of the semifluidized bed is studied. The column diameter and height of the semifluidized bed are 8.1 and 150 cm, respectively. CUSO{sub 4} solution is used as the synthetic wastewater, and Amberlite 200 C resins are employed as the ion-exchange resins. It is found that the effluent Cu{sup 2+} concentration of the semifluidized bed increases as the liquid volumetric flow rate or feed concentration is increased. Moreover, the height of the fluidized bed section keeps decreasing during the ion-exchange process. A mathematical model is developed to describe the ion-exchange process in the semifluidized bed satisfactorily. A comparison of the performance of the semifluidized bed, the fluidized bed, and the packed bed based on the treatment efficiency is also made. It shows that the treatment efficiency is the highest for the semifluidized bed.

Hwang, S.J.; Lu, W.J. [National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Chemical Engineering

1995-04-01

51

Thermal Stability of Ion-Exchange Resins.  

National Technical Information Service (NTIS)

The action of heat, radiation and oxidants on carbon chain 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 deg...

J. P. Aittola J. Chyssler H. Ringberg

1982-01-01

52

Charge Exchange in Collisions Involving Multicharged Ions.  

National Technical Information Service (NTIS)

Recent experimental and theoretical studies related to charge exchange in collisions of hydrogen atom with multicharged ion are reviewed. Two areas of relative collision velocities are separated: 1) slow collisions V=Zsub(a), where Zsub(a)sup(2)/2 - ioniz...

E. L. Duman L. I. Men'shikov

1979-01-01

53

Thermal Analysis of LANL Ion Exchange Column  

SciTech Connect

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.

Laurinat, J.E.

1999-06-16

54

Field Testing of Improved Ion Exchange Techniques.  

National Technical Information Service (NTIS)

Pilot plant field tests were conducted at four sites to evaluate the potential of some new ion exchange techniques to desalt certain brackish waters. A three bed and four bed system were evaluated. The first bed contains a weak-acid resin, the second bed ...

S. A. Bresler F. Husseini E. Kreusch

1974-01-01

55

Thermal Analysis of LANL Ion Exchange Column.  

National Technical Information Service (NTIS)

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 ...

J. E. Laurinat

1999-01-01

56

Solidification of ion exchange resin wastes in hydraulic cement  

SciTech Connect

Work has been conducted to investigate the solidification of ion exchange resin wastes with portland cements. These efforts have been directed toward the development of acceptable formulations for the solidification of ion exchange resin wastes and the characterization of the resultant waste forms. This paper describes formulation development work and defines acceptable formulations in terms of ternary phase compositional diagrams. The effects of cement type, resin type, resin loading, waste/cement ratio and water/cement ratio are described. The leachability of unsolidified and solidified resin waste forms and its relationship to full-scale waste form behavior is discussed. Gamma irradiation was found to improve waste form integrity, apparently as a result of increased resin crosslinking. Modifications to improve waste form integrity are described. 3 tables.

Neilson, R.M. Jr.; Kalb, P.; Fuhrmann, M.; Colombo, P.

1982-01-01

57

Adsorption and selection of rhizobia with ion-exchange papers  

Microsoft Academic Search

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

D. Werner; J. Wilcockson; E. Zimmermann

1975-01-01

58

Ion exchange in a zeolite-molten chloride system  

SciTech Connect

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

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

1997-07-01

59

Electrically switched cesium ion exchange. FY 1997 annual report  

SciTech Connect

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

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

1997-09-01

60

SPEEDUP{trademark} ion exchange column model  

SciTech Connect

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

Hang, T.

2000-03-06

61

Case studies in applying recoflo ion-exchange technology  

NASA Astrophysics Data System (ADS)

Recoflo ion-exchange technology offers improvements over conventional ion-exchange equipment through the use of fine mesh resins; short-depth, fully packed ion-exchange columns; and counter-current regeneration. The system is particularly suited for hydrometallurgical applications due to its ability to process more concentrated feed solutions, the recovery of concentrated-metal product streams, and the much smaller required volume of ion-exchange resin.

Sheedy, Michael

1998-10-01

62

21 CFR 173.21 - Perfluorinated ion exchange membranes.  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 true Perfluorinated ion exchange membranes. 173.21 Section...Treatment § 173.21 Perfluorinated ion exchange membranes. Substances identified...a) of this section may be safely used as ion exchange membranes intended for use...

2010-01-01

63

21 CFR 173.20 - Ion-exchange membranes.  

Code of Federal Regulations, 2010 CFR

...Drugs 3 2010-01-01 2009-04-01 true Ion-exchange membranes. 173.20 Section 173...Polymer Adjuvants for Food Treatment § 173.20 Ion-exchange membranes. Ion-exchange membranes may be safely used in the...

2010-01-01

64

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2010 CFR

...Drugs 3 2009-04-01 2009-04-01 false Ion-exchange resins. 173.25 Section 173.25...Polymer Adjuvants for Food Treatment § 173.25 Ion-exchange resins. Ion-exchange resins may be safely used in the...

2009-04-01

65

21 CFR 173.21 - Perfluorinated ion exchange membranes.  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 false Perfluorinated ion exchange membranes. 173.21 Section...Treatment § 173.21 Perfluorinated ion exchange membranes. Substances identified...a) of this section may be safely used as ion exchange membranes intended for use...

2009-04-01

66

21 CFR 173.20 - Ion-exchange membranes.  

Code of Federal Regulations, 2010 CFR

...Drugs 3 2009-04-01 2009-04-01 false Ion-exchange membranes. 173.20 Section 173...Polymer Adjuvants for Food Treatment § 173.20 Ion-exchange membranes. Ion-exchange membranes may be safely used in the...

2009-04-01

67

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2010 CFR

... 3 2010-01-01 2009-04-01 true Ion-exchange resins. 173.25 Section 173.25 Food...Polymer Adjuvants for Food Treatment § 173.25 Ion-exchange resins. Ion-exchange resins may be safely used in the treatment...

2010-01-01

68

Water softening by combination of ultrasound and ion exchange  

Microsoft Academic Search

Ion exchange resin used in this work was styrene-divinylbenzene co-polymer with sulfonic acid group as a strong acid cation resin. This resin is particularly well suited for the removal of water hardness. In water treatment, commonly used softening processes are chemical precipitation and ion exchange. In this study, a combination of ultrasound and ion exchange was applied for reducing the

M. H. Entezari; M. Tahmasbi

2009-01-01

69

Multiple Bennett acceptance ratio made easy for replica exchange simulations  

NASA Astrophysics Data System (ADS)

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

Procacci, Piero

2013-09-01

70

Ion-exchanged glass waveguides: a review  

Microsoft Academic Search

Passive glass waveguides made by ion-exchange technique are potential candidates for integrated optics (IO) applications. The authors review the advantages in the technology as applied to fabrication of useful single-mode structures. Progress in process, fabrication, modeling, and waveguide performance using different monovalent cation systems and glass compositions is described with emphasis on fiber-compatible single-mode structures prepared from molten baths. It

Ramu V. Ramaswamy; Ramakant Srivastava

1988-01-01

71

ION-EXCHANGE PROPERTIES OF CELLULOSE PHOSPHATE  

Microsoft Academic Search

The ion-exchange properties of cellulose phosphate prepared by the urea-; phosphoric acid method have been investigated. This material has been shown to ; possess a high affinity for certain cations, principally Th\\/sup 4+\\/, Ti\\/sup 4+\\/, ; U\\/sup 4+\\/, Ce\\/sup 4+\\/, Fe\\/sup 3+\\/, ZrO\\/sup 2+\\/, and UOâ \\/sup 2+\\/, ; which are adsorbed from 4N-acid. The influence of the preparative conditions

A. J. Head; N. F. Kember; R. P. Miller; R. A. Wells

1958-01-01

72

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

PubMed

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

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

2013-08-07

73

Novel silica-based ion exchange resin  

SciTech Connect

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

Gula, M.; Harvey, J.

1996-12-31

74

Ion Exchange Temperature Testing with SRF Resin  

SciTech Connect

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

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

2012-03-01

75

Electrochemical ion exchange of LOMI decontamination solutions  

SciTech Connect

The objective of the LOMI Electrochemical Ion Exchange (ELOMIX) process is to reduce the volume of waste arising from LOMI decontamination operations. This is achieved by using the conventional ion exchange resin as an intermediate, rather than a final waste form. Radioactive and metal ion constitutents removed during the decontamination are converted by the process to a metallic form. In its simplest form the ELOMIX cell consists of three compartments, (anode, cathode and resin) separated by cation permeable membranes. In the resin compartment, radioactive and chemical components are removed from the flowing solution by the resin. These components are then migrated under the influence of an electric field into the cathode compartment where metallic elements are deposited. After successful laboratory testing a pilot scale ELOMIX unit was constructed and shipped to Commonwealth Edison's Dresden Unit 2 LOMI decontamination in October 1990. The pilot-scale cell was tied in to the decontamination equipment. The cell operated successfully during three LOMI steps, processing a total of 165 resin bed volumes of solution, far exceeding the normal capacity of the ion exchange resin. Removal efficiencies for iron and radioactivity were good throughout the test. The ELOMIX unit was successfully operated in the time, operational and safety constraints of a reactor decontamination. The main benefits of the process are reduced waste volume, and greater chemical and radiation stability of the waste, which is particularly relevant to full system decontamination. Although the testing to date has focused on the LOMI process, the ELOMIX technique could in principle be applied to be other decontamination processes. 13 figs., 1 tab.

Bradbury, D.; Elder, G.R. (Bradtec Ltd., Bristol (UK))

1991-05-01

76

Novel silica-based ion exchange resin  

SciTech Connect

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.

NONE

1997-11-01

77

Biodegradation of ion-exchange media  

SciTech Connect

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

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

1988-01-01

78

Fixation of radioactive ions in porous media with ion exchange gels  

DOEpatents

A method is provided for fixing radioactive ions in porous media by injecting into the porous media water-soluble organic monomers which are polymerizable to gel structures with ion exchange sites and polymerizing the monomers to form ion exchange gels. The ions and the particles of the porous media are thereby physically fixed in place by the gel structure and, in addition, the ions are chemically fixed by the ion exchange properties of the resulting gel.

Mercer, Jr., Basil W. (Pasco, WA); Godfrey, Wesley L. (Aiken, SC)

1979-01-01

79

Silicon Removal from Waste Simulants via Ion Exchange  

Microsoft Academic Search

examine a number of silica removal technologies to assist the processing of DWPF recycle water. Ion exchange is used commercially to remove soluble silicate ions and colloidal silica from various process waters. Three candidate ion exchange resins were selected after a literature search showed a potential applicability for DWPF Recycle. The results of these scouting tests showed the resins to

Wilmarth

2002-01-01

80

Anisotropic microporous supports impregnated with polymeric ion-exchange materials  

DOEpatents

Novel ion-exchange media are disclosed, the media comprising polymeric anisotropic microporous supports containing polymeric ion-exchange or ion-complexing materials. The supports are anisotropic, having small exterior pores and larger interior pores, and are preferably in the form of beads, fibers and sheets.

Friesen, Dwayne (Bend, OR); Babcock, Walter C. (Bend, OR); Tuttle, Mark (Bend, OR)

1985-05-07

81

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

ERIC Educational Resources Information Center

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

Foster, N.; And Others

1985-01-01

82

Anisotropic microporous supports impregnated with polymeric ion-exchange materials  

DOEpatents

Novel ion-exchange media are disclosed, the media comprising polymeric anisotropic microporous supports containing polymeric ion-exchange or ion-complexing materials. The supports are anisotropic, having small exterior pores and larger interior pores, and are preferably in the form of beads, fibers and sheets. 5 figs.

Friesen, D.; Babcock, W.C.; Tuttle, M.

1985-05-07

83

Ion Exchange Purification of Bis(2-Ethylhexyl)Phosphoric Acid.  

National Technical Information Service (NTIS)

Bis(2-ethylhexyl)phosphoric acid (HDEHP) may be purified by absorption on a macroreticular, strong base anion exchange resin. Properties of ion exchange purified HDEHP are in excellent agreement with literature values. (ERA citation 02:025119)

C. B. Honaker W. W. Schulz

1976-01-01

84

Multicomponent liquid ion exchange with chabazite zeolites  

SciTech Connect

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

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

1993-10-01

85

Transesterification of brazilian vegetable oils with methanol over ion-exchange resins  

Microsoft Academic Search

The transesterification of several Brazilian vegetable oils with methanol was carried out at 60C in the presence of several\\u000a ion-exchange resins having different structures. The vegetable oils used were from Babassu coconut, corn, palm, palm kernel,\\u000a and soybean. The effect of the methanol\\/oil mole ratio and the influences of the structure of the ion-exchange resin and the\\u000a type of vegetable

Simone C. M. dos Reis; Elizabeth R. Lachter; Regina S. V. Nascimento; Jorge A. Rodrigues; Marcelli Garcia Reid

2005-01-01

86

Conducting polymers as ion-exchangers for water purification  

Microsoft Academic Search

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

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

2001-01-01

87

Synthetic inorganic ion exchange materials XLIV: synthesis and ion exchange properties of cubic niobic acid (HNbO 3)  

Microsoft Academic Search

A cubic niobic acid (C-NbA) was synthesized by Li+\\/H+ ion exchange reaction with an 8 M (mol dm?3) nitric acid solution from LiNbO3. The LiNbO3 was obtained by heating a mixture of Li2CO3 and Nb2O5 with molar ratio of 1:1 at 900°C for 24 h. X-ray diffraction pattern of C-NbA was indexed to a cubic structure (space group Im3), with

Tohru Ohsaka; Mitsuo Abe; Yasushi Kanzaki; Takashi Kotani; Sachio Awano

1999-01-01

88

The role of SBR mixed liquor volume exchange ratio in aerobic granulation  

Microsoft Academic Search

Four sequencing batch reactors (SBR) were operated at different volume exchange ratios of 20–80%. Results showed that a rapid aerobic granulation could be achieved in SBR run at high volume exchange ratios, and the characteristics of mature aerobic granules in terms of mean size, SVI, granule fraction, EPS and calcium content were all closely related to the volume exchange ratio

Zhi-Wu Wang; Yu Liu; Joo-Hwa Tay

2006-01-01

89

Scintillating 99Tc Selective Ion Exchange Resins  

SciTech Connect

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

Mitchell Greenhalgh; Richard D. Tillotson

2012-07-01

90

Radiation testing of organic ion exchange resins  

SciTech Connect

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

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

1995-09-01

91

Elaboration and chemical reactivity of enzyme modified ion exchanging textiles  

Microsoft Academic Search

Ion exchanging textile are used as organic supports for enzyme immobilisation with the aim of developing reactive fibrous materials able to be substituted for membrane systems in bioreactors or acting for instance as reactive bags for waste treatment devices, thus extending the range of their potential applications. The cationic or anionic sites of ion exchanging textiles are used for the

M Amounas; V Magne; C Innocent; E Dejean; P Seta

2002-01-01

92

Method for permanently storing radioactive ion exchanger resins  

Microsoft Academic Search

A method is claimed for forming a hardened product containing a radioactive ion exchanger resin in a condition for permanent, noncontaminating storage, by the steps of: providing, before fixing, a mass of such ion exchanger resin saturated in water, the resin being at least one resin selected from the group consisting of spherical resins and powdered resins; mixing the resin

S. Kunze; G. Eden; R. Koster

1984-01-01

93

Ammonium removal using ion exchange and biological regeneration  

Microsoft Academic Search

A new concept for ammonium removal from secondary effluent by zeolite followed by bioregeneration has been studied. In contrast to other studies of hybrid biological-ion exchange multireactor systems, the proposed process uses the ion exchange material, zeolite, as a carrier for the nitrifying biomass. Therefore, the entire process is carried out in a single reactor. Since all the ammonium from

Ori Lahav; Michal Green

1998-01-01

94

Ion exchange membranes: State of their development and perspective  

Microsoft Academic Search

During the last 50 years, ion exchange membranes have evolved from a laboratory tool to industrial products with significant technical and commercial impact. Today ion exchange membranes are receiving considerable attention and are successfully applied for desalination of sea and brackish water and for treating industrial effluents. They are efficient tools for the concentration or separation of food and pharmaceutical

Tongwen Xu

2005-01-01

95

Heated ion exchange process for the recovery of uranium  

SciTech Connect

The present invention relates to an improved method for the recovery of uranium values from a uranium-containing lixiviant by passing the lixiviant through a heated ion exchange resin to cause the resin to retain uranium values. The uranium values are subsequently recovered from the ion-exchange resin.

Fletcher, A.

1984-02-07

96

Electrical and magnetic properties of ion-exchangeable layered ruthenates  

Microsoft Academic Search

An ion-exchangeable ruthenate with a layered structure, K0.2RuO2.1, was prepared by solid-state reactions. The interlayer cation was exchanged with H+, C2H5NH3+, and ((C4H9)4N+) through proton-exchange, ion-exchange, and guest-exchange reactions. The electrical and magnetic properties of the products were characterized by DC resistivity and susceptibility measurements. Layered K0.2RuO2.1 exhibited metallic conduction between 300 and 13K. The products exhibited similar magnetic behavior

Wataru. Sugimoto; Masashi Omoto; Katsunori Yokoshima; Yasushi Murakami; Yoshio Takasu

2004-01-01

97

Ion-exchange properties of industrial flat glass  

Microsoft Academic Search

A study of the ion-exchange processes in a glass-fused salt system makes it possible to determine the various thermodynamic characteristics of both the exchange process and of the glass. These characteristics are necessary for the development of the optimum parameters for strengthening various glass products. The aim of the present work was to study the ion-exchange properties of industrial flat

T. V. Permyakova; V. V. Moiseev; G. E. Sheshukova; T. G. Chernyakova; E. V. Sobolev; O. V. Shcheglova; N. E. Tikhomorova; T. A. Zykova

1981-01-01

98

Ion exchanged potassium titanoniobate as photocatalyst under visible light  

Microsoft Academic Search

Potassium titanoniobate (KTiNbO5) was synthesized by solid-state reaction. The potassium ion of KTiNbO5 was exchanged for hydrogen ion in hydrochloric acid, and the sample was heat-treated. The shrinkage of the distance between\\u000a titanoniobate layers that arise from ion-exchange was observed by using X-ray diffraction. The absorption edges of the UV–Vis\\u000a spectra for the ion exchanged samples which were treated at

Koichi Inoue; Satoshi Suzuki; Masayuki Nagai

2010-01-01

99

Trivalent ion exchange in beta' alumina. Technical report  

SciTech Connect

Ion exchange techniques were used to substitute trivalent cations for the sodium ions present in sodium beta alumina single crystals. Complete replacement was achieved using Gd3+, Nd3+, and Eu3+ ions in molten salts. The conductivity of Gd3+ beta alumina was measured and optical properties of Nd3+ exchanged materials were studied. The trivalent beta aluminas appear to be the first solid electrolytes to exhibit rapid trivalent cation motion at moderate temperatures.

Dunn, B.; Farrington, G.C.

1984-07-06

100

Vibrational spectroscopy of ion exchange membranes  

NASA Astrophysics Data System (ADS)

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

Kumari, Dunesh

101

Synthesis of layered sodium lanthanum selenide through ion exchange reactions  

SciTech Connect

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

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

2009-04-02

102

Acid–base properties of ion exchangers. I. Optimising of potentiometric titration of ion exchangers exemplified by carboxylic acid resins  

Microsoft Academic Search

The aim of this work was to determined conditions for fast titration the ion exchanger in the one-sample experiment allowing obtaining its equilibrium titration curve. Carboxylic acid ion exchangers KB-4 and Dowex MAC-3 were taken as examples. They were titrated under different conditions with NaOH, KOH and Ba(OH)2. The forward and backward titration of concentrated immersions of finely ground ion

V. S Soldatov; Z. I Sosinovich; T. A Korshunova; T. V Mironova

2004-01-01

103

Ion exchange properties of Japanese natural zeolites in seawater.  

PubMed

Ion exchange properties of five different Japanese natural zeolites in seawater were examined. Sodium ions could be reduced by all zeolites, although anions, Cl(-) and SO(4)(2-), in seawater showed barely changes. Natural zeolite desalination treatment mainly depends on the ion exchange between Na(+), K(+) and Mg(2+) in seawater and Ca(2+) in natural zeolite. This study found that mordenite is superior to clinoptilolite for use in Na(+) reduction. Mordenite with high cation exchange capacity containing Ca(2+) resulted in the highest Na(+) reduction from seawater. PMID:23303099

Wajima, Takaaki

2013-01-01

104

Ion-exchanged glass waveguide technology: a review  

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

105

Ion chromatographic investigation of the ion-exchange properties of microdisperse sintered nanodiamonds  

Microsoft Academic Search

The possibility of using sintered diamonds as a stationary phase in ion chromatography has been evaluated. Bare sintered synthetic nanodiamonds demonstrated the properties of a weak cation-exchanger. The observed ion-exchange selectivity is similar to carboxylic type cation-exchangers. The regularities of retention of alkali, alkaline-earth and transition metal ions on a column packed with sintered nanodiamonds in dilute nitric acid were

Pavel N. Nesterenko; Olga N. Fedyanina; Yurii V. Volgin; Phil Jones

2007-01-01

106

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

Microsoft Academic Search

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

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

2008-01-01

107

Cesium Ion Exchange Loading Kinetics Testing with SRF Resin  

SciTech Connect

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

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

2012-11-02

108

Tc-99 Ion Exchange Resin Testing  

SciTech Connect

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

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

2010-08-01

109

FRACTIONATION OF COMPLEX MIXTURES USING AND ION-EXCHANGE METHODOLOGY  

EPA Science Inventory

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

110

Application of pressurized ion exchange to separations of transplutonium elements  

SciTech Connect

High-pressure ion exchange chromatography, used first for nucleic acid separations, was applied to the production of the heavier actinides, particularly the transcurium elements. Its use at the TRU plant is described. Future developments are considered briefly. (DLC)

Campbell, D.O.

1980-01-01

111

Carbonate and Bicarbonate Ion Transport in Alkaline Anion Exchange Membranes.  

National Technical Information Service (NTIS)

Anion exchange membranes (AEMs) are being developed for potential use in fuel cell systems which include portable power applications. In a fuel cell, these membranes transport hydroxide ions from the cathode to the anode. If carbon dioxide is present, car...

A. A. Peracchio A. M. Kiss G. J. Nelson K. N. Grew T. D. Myles

2013-01-01

112

Effects of ionizing radiation on modern ion exchange materials.  

National Technical Information Service (NTIS)

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/diviny...

S. F. Marsh K. K. S. Pillay

1993-01-01

113

Minor Actinide Separations Using Ion Exchangers or Ionic Liquids.  

National Technical Information Service (NTIS)

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 c...

A. Clearfield A. E. Visser D. T. Hobbs N. J. Bridges

2011-01-01

114

Selenium Removal from Drinking Water by Ion Exchange.  

National Technical Information Service (NTIS)

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

J. E. Maneval G. Klein J. Sinkovic

1985-01-01

115

Low-level liquid waste decontamination by ion exchange.  

National Technical Information Service (NTIS)

Improved processes are being developed to treat contaminated liquid wastes that have been and continue to be generated at Oak Ridge National Laboratory using both inorganic and organic ion-exchange methods. Nickel and cobalt hexacyanoferrate(2) compounds ...

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

1990-01-01

116

Low-level liquid waste decontamination by ion exchange.  

National Technical Information Service (NTIS)

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 hexacy...

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

1991-01-01

117

Samarium Ion Exchanged Montmorillonite for High Temperature Cumene Cracking Reaction  

NASA Astrophysics Data System (ADS)

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

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

2011-02-01

118

Ion-ion charge exchange cross-sections for heavy ion fusion  

NASA Astrophysics Data System (ADS)

In heavy ion fusion the compression of the DT-pellet requires adequate accelerators and storage rings for the driving projectile ions. The design of such storage rings crucially depends on the expected particle losses due to charge-changing collisions between the stored ions. Although the kinetic energy of driver ions in a heavy ion fusion scenario is in the order of several GeV, the relative kinetic energy of intrabeam ion-ion collisions is only in the keV region and therefore attainable in an ion-ion crossed-beams experiment. In this paper we report on the investigation of charge exchange in collisions between quadruply charged xenon and bismuth ions. With the knowledge of these cross-sections we were able to estimate the particle losses from a 100Tm synchrotron which is one of the possible options for a future GSI upgrade. The relevance of such a synchrotron for plasma physics and HIF is given by the possible intensity of 1013 ions and approximately 40kJ bunch energy.

Trassl, R.; Bräuning, H.; Diemar, K. v.; Melchert, F.; Salzborn, E.; Hofmann, I.

2001-05-01

119

Strengthening of container glasses by ion-exchange dip coating  

Microsoft Academic Search

The strengthening of industrial grade sodium aluminosilicate glasses was investigated using halide base ion-exchange by dip coating. Li ion-exchange showed a significant flexural strength enhancement of 16–163% up to a maximum value of 506MPa for container glass composition with progressively increasing network modifier additions of alumina from 3 to 10wt%. The results showed a linear relationship between square root of

K. K. Mallick; D. Holland

2005-01-01

120

Simulation of an ion exchange membrane electrodialysis process for continuous saline water desalination  

Microsoft Academic Search

A computer program is developed and a continuous ion exchange membrane process is simulated applying a constant voltage between electrodes. Inputting membrane characteristics, electrodialyzer specifi cations and electrodialysic conditions into the program, the performance of an electrodialyzer is predicted. Salt concentration in a desalted solution, current efficiency, desalting ratio, water recovery, energy consumption, current density distribution, current density non-uniformity coefficient,

Yoshinobu Tanaka

2010-01-01

121

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

Microsoft Academic Search

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

Sami ?ahin

2002-01-01

122

THE DETERMINATION OF MAGNESIUM IN ZIRCONIUM USING ION EXCHANGE CHROMATOGRAPHY  

Microsoft Academic Search

The method is based upon the ability of zirconium to form an easily ; soluble oxalate complex compound which is not adsorbed by a cation exchanger ; (catfonite). The magnesium in the solution is, however, adsorbed by the ; cationite and can then be eluted with hydrochloric acid. An ion exchange resin ; with SOâH as the active group was

S. V. Yelinson; M. S. Limonik

1958-01-01

123

Removal of natural organic matter by ion exchange  

Microsoft Academic Search

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

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

2002-01-01

124

Thorium Uptake on Synthetic Inorganic Ion Exchangers  

Microsoft Academic Search

Birnessite, antimonysilicate and their cation-exchange derivatives were tested to take up thorium. Sorption experiments were performed in different concentrations of acid, and sodium, potassium and calcium nitrate solutions in order to evaluate the influence of cations that likely to be present in waste effluents. Variation in the magnitude and mechanism of thorium sorption on the exchangers was ascribed to structural

Lina Al-Attar; Youssef Budeir

2011-01-01

125

Water softening by combination of ultrasound and ion exchange.  

PubMed

Ion exchange resin used in this work was styrene-divinylbenzene co-polymer with sulfonic acid group as a strong acid cation resin. This resin is particularly well suited for the removal of water hardness. In water treatment, commonly used softening processes are chemical precipitation and ion exchange. In this study, a combination of ultrasound and ion exchange was applied for reducing the hardness of water. The rate of exchange or kinetics of ion exchange is governed by several parameters. Therefore, important variables such as intensity of ultrasound, amount of resin, concentration of ions and contact time were investigated. The experimental data related to the removal of magnesium and calcium ions were fitted properly with Langmuir model. The kinetic of removal for both ions was pseudo-first-order. In point of mechanism, the internal porous and film diffusion were both effective in the process. The capacity of sorption and the velocity of removal were higher in the presence of ultrasound than control method and this is related to the cavitation process. PMID:19014894

Entezari, M H; Tahmasbi, M

2008-10-15

126

New Metal Niobate and Silicotitanate Ion Exchangers: Development and Characterization  

SciTech Connect

This renewal proposal outlines our current progress and future research plans for ion exchangers: novel metal niobate and silicotitanate ion exchangers and their ultimate deployment in the DOE complex. In our original study several forms (including Cs exchanged) of the heat treated Crystalline Silicotitanates (CSTs) were fully characterized by a combination of high temperature synthesis and phase identification, low temperature synthesis and phase identification, and thermodynamics. This renewal proposal is predicated on work completed in our current EMSP program: we have shown preliminary data of a novel class of niobate-based molecular sieves (Na/Nb/M/O, M = transition metals), which show exceptionally high selectivity for divalent cations under extreme conditions (acid solutions, competing cations), in addition to novel silicotitanate phases which are also selective for divalent cations. Furthermore, these materials are easily converted by a high temperature in-situ heat treatment into a refractory ceramic waste form with low cation leachability. The new waste form is a perovskite phase, which is also a major component of Synroc, a titanate ceramic waste form used for sequestration of HLW wastes from reprocessed, spent nuclear fuel. These new niobate ion exchangers also shown orders of magnitude better selectivity for Sr2+ under acid conditions than any other material. The goal of the program is to reduce the costs associated with divalent cation waste removal and disposal, to minimize the risk of contamination to the environment during ion exchanger processing, and to provide DOE with materials for near-term lab-bench stimulant testing, and eventual deployment. The proposed work will provide information on the structure/property relationship between ion exchanger frameworks and selectivity for specific ions, allowing for the eventual ''tuning'' of framework for specific ion exchange needs. To date, DOE sites have become interested in on-site testing of these materials; ongoing discussions and initial experiments are occurring with Dr. Dean Peterman, Idaho National Engineering and Environmental Laboratory (INEEL) (location of the DOE/EM Waste Treatment Focus Area), and Dr. John Harbour, Savannah River Site (SRS). Yet the materials have not been optimized, and further research and development of the novel ion exchangers and testing conditions with simulants are needed. In addition, studies of the ion exchanger composition versus ion selectivity, ion exchange capacity and durability of final waste form are needed. This program will bring together three key institutions to address scientific hurdles of the separation process associated with metal niobate and silicotitanate ion exchangers, in particular for divalent cations (e.g., Sr2+). The program involves a joint effort between researchers at Pacific Northwest National Laboratory, who are leaders in structure/property relations in silicotitanates and in waste form development and performance assessment, Sandia National Laboratories, who discovered and developed crystalline silicotitanate ion exchangers (with Texas A&M and UOP) and also the novel class of divalent metal niobate ion exchangers, and the Thermochemistry Facility at UC Davis, who are world renowned experts in calorimetry and have already performed extensive thermodynamic studies on silicotitanate materials. In addition, Dr. Rodney Ewing of University of Michigan, an expert in radiation effects on materials, and Dr. Robert Roth of the National Institute of Standards and Technology and The Viper Group, a leader in phase equilibria development, will be consultants for radiation and phase studies. The research team will focus on three tasks that will provide both the basic research necessary for the development of highly selective ion exchange materials and also materials for short-term deployment within the DOE complex: (1) Structure/property relationships of a novel class of niobate-based molecular sieves (Na/Nb/M/O, M = transition metals), which show exceptionally high selectivity for divalent cations un

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

2003-12-05

127

ION EXCHANGE PROCESS FOR THE RECOVERY AND PURIFICATION OF MATERIALS  

Microsoft Academic Search

A process for the recovery of certain metallic ions from aqueous ; solutions by ion exchange techniques is described. It is applicable to elements ; such as vanadium, chromium, nnanganese, and the like, which are capable of ; forming lower valent cations soluble in aqueous solutions and which also form ; ldgher valent anions soluble in aqueous acidic solutions. For

R. S. Long; R. H. Bailes

1958-01-01

128

Tunable selectivity of lanthanide ion exchange within a coordination polymer.  

PubMed

The exchange of lanthanide(III) ions (Ln(3+)) between a solution and a coordination polymer (CP) formed by cerium(III) or samarium(III) ion and an organophosphorous ligand has been studied. The CPs exhibit distinctive Ln(3+) affinity that varies with a small change in its framework, depending on the central Ln(3+). PMID:23842409

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

2013-01-01

129

Desalination of brackish waters using ion exchange media.  

SciTech Connect

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

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

2005-01-01

130

Computer prediction of arsenic ion exchange  

Microsoft Academic Search

Anion exchange may be the method of choice for removing arsenic from drinking water provided that the sulfate and total dissolved solids (TDS) levels are not too high. In this process, arsenic-contaminated water, which has been preoxidized to convert arsenite [As(III)] to arsenate [As(V)], is passed through a bed of anion exchange resin in the chloride form. Two important engineering

1995-01-01

131

Heavy-ion charge exchange in the eikonal approximation  

NASA Astrophysics Data System (ADS)

In high-energy collisions (Elab > 50 MeV/nucleon) the eikonal approximation provides a transparent description of heavy-ion exchange reactions. The formalism is applied to the reaction 13N(13C, 13N)13C at 70 MeV/nucleon. The relative contributions of pion- and rho-exchange are determined. It is found that heavy-ion reactions are more sensitive to the one-pion exchange component of the interaction than nucleon-induced charge exchange. The cross section for double charge exchange are estimated, which could be useful for future experiments. Permanent address: Instituto de Física, Universidade Federal do Rio de Janeiro, 21945 Rio de Janeiro, Brazil.

Bertulani, C. A.

1993-03-01

132

Electrical and magnetic properties of ion-exchangeable layered ruthenates  

SciTech Connect

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

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

2004-12-01

133

Preparation and ion-exchange properties of zirconium sulphosphosphonates  

SciTech Connect

A number of layered zirconium phosphite arylphosphonate and zirconium phosphate arylphosphonate mixed derivatives were prepared. These compounds were readily sulfonated in fuming sulfuric acid and the resultant sulfonates behaved as strong-acid ion exchangers. In the case where the aryl group bridged across layers, a non-swelling exchanger resulted, and these solids showed ion exclusion towards large complexes. They also exhibited the selectivity sequences lithium + greater than sodium + less than potassium + and magnesium + greater than calcium + less than barium +. In the exchanger in which the layers were not connected, large degrees of swelling to the point of colloid formation, were observed. As a consequence, the rates of exchange were very high. The non-crosslinked exchanger showed increased selectivity was remarkable and may stem from a combination of favorable electrostatic and steric factors.

Yang, C.Y.; Clearfield, A.

1987-01-01

134

Ion-exchange and iontophoresis-controlled delivery of apomorphine.  

PubMed

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

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

2012-12-01

135

Ion-exchange purification of aqueous solutions of secondary caprolactam  

Microsoft Academic Search

Caprolactam is recovered from the waste products of the primary and secondary raw materials by a series of extraetion processes with seeondary eaprolactam one of which consists of filtering the solutions through ion-exchange resins \\/1-6\\/. Some ion-exohange apparatus for purifying caprolaetoam solutions use imported ion-exehange resins which ean be replaeed with advantage with a Soviet produet. The writers earried out

Z. V. Arkhangelskaya; V. N. Gorodnicheva; O. A. Sokolova; A. S. Smirnov; P. D. Novikov

1971-01-01

136

Studies of Ion Exchange and Chelation Compounds Adsorbed on Granular Graphite.  

National Technical Information Service (NTIS)

Several compounds that have particular ion exchange or chelation properties have been adsorbed on granular graphite and coke. The resulting materials exhibit ion exchange and chelation properties similar to typical commercial exchange resins used for sepa...

J. L. Hern

1976-01-01

137

Silicon Removal from Waste Simulants via Ion Exchange  

SciTech Connect

examine a number of silica removal technologies to assist the processing of DWPF recycle water. Ion exchange is used commercially to remove soluble silicate ions and colloidal silica from various process waters. Three candidate ion exchange resins were selected after a literature search showed a potential applicability for DWPF Recycle. The results of these scouting tests showed the resins to be chemically stable in the alkaline environment of DWPF recycle. However, the resins were not effective at removing silicon. Additionally, results of silica analyses showed the silicon solubility in these feed solutions for ion exchange were still high after further acidification with respect to the goal of silicon removal. This suggests very strongly that pH adjustment (from 14 to 9), as a silicon removal technology is not viable.

Wilmarth, W.R.

2002-09-23

138

Coccolith B/Ca ratios using SIMS ion probe analysis  

NASA Astrophysics Data System (ADS)

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

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

2009-04-01

139

Ion exchange performance of commercial crystalline silicotitanates for cesium removal  

SciTech Connect

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.

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

1996-03-01

140

SELENIUM OXIDATION AND REMOVAL BY ION EXCHANGE  

EPA Science Inventory

Strong-base anion exchange was evaluated as a process for the removal of trace quantities of selenium from groundwater. The efficiency of the process was found to be dependent on the oxidation state of selenium, with the selenate anion (Se(VI)) having a greater affinity for the a...

141

Charge exchange of multiply charged laser plasma ions with rare-gas jet atoms  

SciTech Connect

The interaction of a gas jet (He, Ne, Xe) with the incident laser plasma from a solid target [B, (CH{sub 2}){sub n}, (CF{sub 4}){sub n}] removed by {approx}1 cm is investigated. Line spectra arising from the charge exchange of multiply charged plasma ions with rare-gas atoms are recorded in the multiply charged ions-gas interaction region. The ratios between the partial cross sections of the charge exchange with the production of these ions in excited states are determined from the relative intensities of the Balmer series transitions in BV and CVI ions. These results are compared with theoretical data. (interaction of laser radiation with matter. laser plasma)

Beigman, I L; Levashov, V E; Mednikov, K N; Pirozhkov, A S; Ragozin, E N; Tolstikhina, I Yu [P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2007-11-30

142

MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS  

SciTech Connect

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.

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

2011-09-20

143

The use of multiple ion exchange to produce energy transfer in beta-aluminas  

SciTech Connect

The preparation of single crystals of {beta}-alumina containing two trivalent lanthanide species is described. The use of eutectic melts enables the two rare earth species to be introduced during a single ion exchange process. Energy transfer in crystals containing Ce/sup +3//Nd/sup +3/ and Ce/sup +3//Tb/sup +3/ is shown. High transfer efficiencies were measured for crystals with low sensitizer-to-activator ion concentration ratios. Up-conversion processes were observed in crystals doped with Yb/sup +3/ and Er/sup +3/ ions.

Momoda, L.A.; Barrie, J.D.; Dunn, B. (California Univ., Los Angeles, CA (USA). Dept. of Materials Science and Engineering)

1989-07-01

144

Evaluation of electrochemical ion exchange for cesium elution  

SciTech Connect

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.

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

1996-04-01

145

Mixed matrix microporous hollow fibers with ion-exchange functionality  

Microsoft Academic Search

Heterogeneous hollow fiber membranes with cation exchange functionality are prepared using a wet spinning technique. The spinning dope solutions are prepared by dispersing finely ground cation ion-exchange resin (CER) particles in an N-methyl pyrrolidone solution of polysulfone (PSF). The polymer solution is shaped into a hollow fiber by forcing the solution through a tube-in-orifice spinneret followed by phase inversion in

R. Kiyono; G. H. Koops; M. Wessling; H. Strathmann

2004-01-01

146

Selenium oxidation and removal by ion exchange  

SciTech Connect

Strong-base anion exchange was evaluated as a process for the removal of trace quantities of selenium from groundwater. The efficiency of the process was found to be dependent on the oxidation state of selenium, with the selenate anion (Se(VI)) having a greater affinity for the anion-exchange resin than selenite or biselenite anions (Se(IV)). An analytical method was developed to measure the concentrations of Se(IV) and Se(VI) (i.e., to determine the speciation of selenium) at trace concentrations in groundwater. The oxidation of Se(IV) to Se(VI) at trace concentration in groundwater was studied with this new analytical method.

Boegel, J.V.; Clifford, D.A.

1986-03-01

147

Comparison of chromatographic ion-exchange resins  

Microsoft Academic Search

Strong and weak cation-exchangers were compared for a number of chromatographic parameters, i.e. pH dependence, efficiency, binding strength, particle size distribution, static and dynamic capacity, and scanning electron microscopy (SEM) pictures. Chromatographic resins investigated were Fractogel EMD SO3? (M), Fractogel EMD SE Hicap (M), Fractogel EMD COO? (M), MacroPrep 25S, MacroPrep High S, MacroPrep CM, CM HyperZ, and Matrex Cellufine

Arne Staby; Jan H. Jacobsen; Ronni G. Hansen; Ulla K. Bruus; Inge Holm Jensen

2006-01-01

148

Recovery of boric acid from ion exchangers  

DOEpatents

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 .sup.10 B which may be found in some nuclear reactor coolant solutions.

Pollock, Charles W. (Richland, WA)

1976-01-01

149

Catalysis using hydrous metal oxide ion exchangers  

DOEpatents

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

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

1983-07-21

150

Catalysis using hydrous metal oxide ion exchanges  

DOEpatents

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

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

1985-01-01

151

Experimental study of copper-alkali ion exchange in glass  

NASA Astrophysics Data System (ADS)

Copper-alkali ion exchange was performed by immersing different silicate glasses (soda-lime and BK7) in different molten eutectic salt baths (CuSO4:Na2SO4 and CuSO4:K2SO4). The obtained optical waveguides were characterized by m-lines spectroscopy for the determination of refractive index profiles, and by secondary ion mass spectrometry for the concentration profiles of the ion species involved in the exchange process. The different oxidation states of copper inside the glass structure were studied by electron paramagnetic resonance and x-ray absorption techniques. Interdiffusion copper coefficients were also determined. The Cu-alkali exchange was observed to give rise to local structural rearrangement of the atoms in the glass matrix. The Cu+ ion was found to mainly govern the exchange process, while competition between Cu-Na and K-Na exchanges occurred when a potassium sulfate bath was used. In this case, significant waveguide modal birefringence was observed.

Gonella, F.; Caccavale, F.; Bogomolova, L. D.; D'Acapito, F.; Quaranta, A.

1998-02-01

152

Rupture loop annex ion exchange RLAIX vault deactivation  

SciTech Connect

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.

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

1996-08-01

153

An Empirical Formula from Ion Exchange Chromatography and Colorimetry  

NASA Astrophysics Data System (ADS)

Experimental determination of the empirical formula for sodium salicylate, Nax(C7H5O3)y, using colorimetry and cation exchange. A Beer's Law plot is prepared for salicylate using 0.0050 M salicylic acid solution. Colorimetric analysis is performed on the salicylate ion in the form of an aqueous ferric complex, which is intensely violet-red, using a simple, inexpensive colorimeter constructed from readily available electronic parts and PVC pipe. Determination of sodium content is conducted using cation exchange, using simple re-usable exchange columns, followed by titration with OH-. The procedure is involved, yet has been conducted by high school chemistry students as a lab final.

Johnson, Steven D.

1996-12-01

154

Transport limitations in ion exchange membranes at low salt concentrations  

Microsoft Academic Search

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

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

2010-01-01

155

Fission product ion exchange between zeolite and a molten salt  

NASA Astrophysics Data System (ADS)

The electrometallurgical treatment of spent nuclear fuel (SNF) has been developed at Argonne National Laboratory (ANL) and has been demonstrated through processing the sodium-bonded SNF from the Experimental Breeder Reactor-II in Idaho. In this process, components of the SNF, including U and species more chemically active than U, are oxidized into a bath of lithium-potassium chloride (LiCl-KCl) eutectic molten salt. Uranium is removed from the salt solution by electrochemical reduction. The noble metals and inactive fission products from the SNF remain as solids and are melted into a metal waste form after removal from the molten salt bath. The remaining salt solution contains most of the fission products and transuranic elements from the SNF. One technique that has been identified for removing these fission products and extending the usable life of the molten salt is ion exchange with zeolite A. A model has been developed and tested for its ability to describe the ion exchange of fission product species between zeolite A and a molten salt bath used for pyroprocessing of spent nuclear fuel. The model assumes (1) a system at equilibrium, (2) immobilization of species from the process salt solution via both ion exchange and occlusion in the zeolite cage structure, and (3) chemical independence of the process salt species. The first assumption simplifies the description of this physical system by eliminating the complications of including time-dependent variables. An equilibrium state between species concentrations in the two exchange phases is a common basis for ion exchange models found in the literature. Assumption two is non-simplifying with respect to the mathematical expression of the model. Two Langmuir-like fractional terms (one for each mode of immobilization) compose each equation describing each salt species. The third assumption offers great simplification over more traditional ion exchange modeling, in which interaction of solvent species with each other is considered. (Abstract shortened by UMI.)

Gougar, Mary Lou D.

156

Inline Monitors for the SRS Small Column Ion Exchange Process.  

National Technical Information Service (NTIS)

A Small Column Ion Exchange (SCIX) system, designed by the Oak Ridge and Savannah River National Laboratories (ORNL and SRNL), is a potential way to reduce Cs-137 concentrations in high-level radioactive waste at the Savannah River Site (SRS). SRNL has de...

V. R. Casella R. A. Sigg F. S. Moore T. N. Riley

2005-01-01

157

Small Column Ion Exchange Monitor System Final Report.  

National Technical Information Service (NTIS)

A Small Column Ion Exchange (SCIX) system has been designed by the Oak Ridge and Savannah River National Laboratories (ORNL and SRNL) as a potential way to reduce Cs-137 concentrations in high-level radioactive waste at the Savannah River Site. SRNL was a...

V. R. Casella R. A. Sigg F. S. Moore T. N. Riley S. R. Salaymeh

2004-01-01

158

Copper Removal from A-01 Outfall by Ion Exchange  

SciTech Connect

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.

Oji, L.N.

1999-02-17

159

Gas Separation Using Ion Exchange Membranes: Final Report.  

National Technical Information Service (NTIS)

The objectives of this project were twofold. The primary objective was to demonstrate the concept of using reactive ion exchange membranes (IEMs) containing organic amines for the separation of CO sub 2 and H sub 2 S from coal gasification product gases. ...

J. D. Way R. D. Noble L. A. Powers

1986-01-01

160

Ion exchange for the removal of natural organic matter  

Microsoft Academic Search

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

Brian Bolto; David Dixon; Robert Eldridge

2004-01-01

161

ANION EXCHANGE SEPARATIONS OF METAL IONS IN PARTIALLY NONAQUEOUS SOLUTIONS  

Microsoft Academic Search

A systematic approach to anion exchange in partially nonaqueous solvents ; was initiated. Distribution coefficicients of metal ions for Dowex 1 X8, ; chloride form resin in organic solvent-water mixtures containing hydrochloric ; acid were measured. The organic solvents used were methyl alcohol, ethyl ; alcohol, isopropyl alcohol, acetone, and dioxane. When the organic solvent ; concentration was increased and

D. J. Pietrzyk; J. S. Fritz

1960-01-01

162

Thermal Analysis for Ion-Exchange Column System  

SciTech Connect

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

Lee, S.

2012-12-20

163

Purification of metal plating rinse waters with chelating ion exchangers  

Microsoft Academic Search

A wide range of chelating ion exchangers was tested for their abilities to remove Zn, Ni, Cu and Cd from solutions simulating waste effluents from the metal-plating industry. The task was to reduce metal discharges to the environment so that metal-plating shops could keep up with the modern, more stringent regulations of waste effluents. The resins were tested by batch

Risto Koivula; Jukka Lehto; Leena Pajo; Thomas Gale; Heikki Leinonen

2000-01-01

164

The Ion-Exchange Separation of Zirconium and Hafnium  

Microsoft Academic Search

In the course of a rather cursory examination of the elution of tetra-positive ions from the cation exchange resin Dowex 50 with hydrochloric acid solutions, the authors have discovered a very effective method of separating zirconium from hafnimu. In view of the great labor involved in preparing even reasonably pure hafnium compounds by existing methods, they feel that this procedure

Glenn T. Seaborg

1948-01-01

165

ION EXCHANGE FOR THE REMOVAL OF NITRATE FROM WELL WATER  

EPA Science Inventory

A 1-mgd (3.8-ML/d) ion exchange plant was built in McFarland, Calif., to remove excess concentrations of nitrate from one of the city's supply wells. Data are reported for the semiautomatic mode of operation, during which time the plant has performed satisfactorily. Nitrate has b...

166

Incineration of ion-exchange resins in a fluidized bed  

Microsoft Academic Search

Incineration of ion-exchange resins in a fluidized bed was studied on the pilot plant scale. Granular resins were incinerated mostly in the dry form, while powdered resins were incinerated in an ethanol-water mixture. Incineration converts the organic resin into inert oxide material, which can be immobilized for instance with cement. The weight of the ash was 1 to 20% and

M. Valkiainen; M. Nykyri

1982-01-01

167

Reuse system for powdered ion-exchange resins  

Microsoft Academic Search

A reuse system has been developed for powdered ion-exchange resins generated from nuclear power plants in order to reduce their waste volume. The system consists of: 1. crud removal from resins; 2. decomposition of flocks (flocculated resins); 3. resin separation into cation and anion types; 4. regeneration of each type. The most important points in this system are items 2

K. Funabashi; T. Fukasawa; F. Kawamura; H. Yusa; M. Kikuchi; N. Sasaki; T. Yamadera

1986-01-01

168

ION-EXCHANGE PROCESSES AND MECHANISMS IN GLASSES  

EPA Science Inventory

Recent performance assessment calculations of a disposal system at Hanford, Washington for low activity waste glass show that a Na ion-exchange reaction can effectively increase the radionuclide release rate by over a factor of 1000 and so is a major factor that currently limits ...

169

Treatment of Spent Ion Exchange Resins IAEA Research Coordination Programme.  

National Technical Information Service (NTIS)

Spent ion-exchange resins arising from steam condensate systems, reactor coolant clean-up systems and rad-waste procession, are considered as a specific solid waste management problem. This is the second report on the product characterisation with respect...

K. Balu S. C. Bhatia P. K. Wattal N. Chanana

1981-01-01

170

Small Column Ion Exchange Design and Safety Strategy  

Microsoft Academic Search

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

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

2011-01-01

171

New Advances in Catalysis by Ion-exchange Resins  

Microsoft Academic Search

Current research on the general problems, methods and theory of catalysis by ion-exchange resins as well as new advances in its application in hydrolytic, hydration, and dehydration reactions, the synthesis of esters, alkylation, polymerisation, isomerisation, and condensation are surveyed. The bibliography includes 276 references.

N. G. Polyanskii; V. K. Sapozhnikov

1977-01-01

172

Stress relaxation in glasses strengthened by ion exchange  

Microsoft Academic Search

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

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

1981-01-01

173

SELENIUM REMOVAL FROM DRINKING WATER BY ION EXCHANGE  

EPA Science Inventory

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

174

Stability of tumor necrosis factor-? during ion exchange chromatography  

Microsoft Academic Search

Denaturation of target protein by various separation and purification steps contributes significant part to the total product loss in bioseparation. The conformational change and accompanying loss of activity of tumor necrosis factor-a during ion exchange chromatography was reversible and was decreased by adding polyethylene glycol 200 at 2 to 5% (v\\/v) to the eluting solution.

Ming Li; Yunshan Wang; Weijun Li; Zhiguo Su

2003-01-01

175

Routine activation analysis with an automatic ion-exchange apparatus  

Microsoft Academic Search

Summary The application of the automatic ion-exchange apparatus by Samsahl, to the determination of trace elements in biological, medical and environmental samples, is described. By this method it is possible to analyse for up to about 40 trace elements in various materials. Because of the large number of elements determined by this device, a flux-monitor irradiation method is applied for

Peter Schramel

1978-01-01

176

Low-level liquid waste decontamination by ion exchange  

Microsoft Academic Search

Improved processes are being developed to treat contaminated liquid wastes that have been and continue to be generated at Oak Ridge National Laboratory using both inorganic and organic ion-exchange methods. Nickel and cobalt hexacyanoferrate(2) 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

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

1990-01-01

177

Low-level liquid waste decontamination by ion exchange  

Microsoft Academic Search

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.

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

1991-01-01

178

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

PubMed

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

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

2013-10-22

179

Separation of americium from curium by oxidation and ion exchange.  

PubMed

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

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

2012-07-31

180

Magnetization reversal with variation of the ratio of the anisotropy energies in exchange bias systems  

SciTech Connect

We systematically vary the ratio of the exchange and ferromagnetic anisotropies in a single multilayered system in finally unravelling the mysteries of magnetization reversal of exchange coupled systems. This is particularly possible due to increasing unidirectional exchange anisotropies in our multilayer system which we saw earlier from sequential switching of exchange coupled layers along the stack with increasing applied field strengths. Here, by introducing different directions ({theta}) of the applied field with respect to the unidirectional anisotropy direction, we have varied two different energy parameters: (i) the exchange anisotropy for each layer (ii) the ferromagnetic anisotropy. Our polarized neutron measurements thus show a gradual crossover from layer flipping (domain-wall motion) for low torque regimes of the effective field to coherent rotation for high torque regimes. We explain these findings within a general and simple model where the angular dependencies for reversal are guided by the relative strengths of Zeeman, exchange, and anisotropy energies.

Paul, Amitesh; Kentzinger, Emmanuel; Ruecker, Ulrich; Brueckel, Thomas [Institut fuer Festkoerperforschung, Forschungszentrum Juelich GmbH, D-52425 Juelich (Germany)

2006-08-01

181

Acid–base properties of ion exchangers. III. Anion exchangers on the basis of polyacrylonitrile fiber  

Microsoft Academic Search

The anion exchange fibers on the basis of industrially produced polyacrylonitrile fiber NITRON with different strong and weak base groups have been described in the paper. Their acid–base properties were characterized by the acidity parameters calculated from the potentiometric titration curves. The method of computer analysis of the titration curves described elsewhere was used. It was established that the ion

A. A. Shunkevich; Z. I. Akulich; G. V. Mediak; V. S. Soldatov

2005-01-01

182

Single Motional Quantum Exchange between Independently Trapped Ions  

NASA Astrophysics Data System (ADS)

The Coulomb coupling of ions in separate potential wells is a key feature of proposals to implement quantum simulation and could enable logic operations to be performed in a multi-zone quantum information processor without the requirement of bringing the ion qubits into the same trapping potential. It might also extend the capabilities of quantum logic spectroscopy to ions that cannot be trapped in the same potential well as the measurement ion, such as oppositely charged ions or even antimatter particles. We report recent results demonstrating tunable coupling of two ^9Be^+ ions held in trapping potentials separated by 40 ?m [1]. The ions are trapped 40 ?m above the surface of a microfabricated planar trap with independently tunable axial frequencies of ˜4 MHz. The trap is cooled to 4.2 K with a helium bath cryostat to suppress anomalous heating and to extend the lifetime of ions from minutes to days. By preparing approximate motional number states with n=0 and n=1 in the respective wells, and tuning the confining wells into resonance, a single quantum of motion is exchanged between the ions in ˜200 ?s. [4pt] [1] arXiv:1011.0473, accepted to Nature.

Brown, K. R.; Ospelkaus, C.; Colombe, Y.; Wilson, A. C.; Leibfried, D.; Wineland, D. J.

2011-06-01

183

Development of Electrochemical Ion Exchange Materials and Techniques for Desalting Water.  

National Technical Information Service (NTIS)

The Thermosorb and Electrosorb methods of desalting, and the present status of the Thermosorb process are described. Both approaches to desalination depend upon combined electrochemical ion exchange effects. In this exchange, ions are reversibly sorbed fr...

A. W. Venolia A. M. Johnson

1968-01-01

184

Grafted megaporous materials as ion-exchangers for bioproduct adsorption.  

PubMed

Megaporous chromatographic materials were manufactured by a three-step procedure, including backbone synthesis, chemical grafting, and introduction of ion-exchange functionality. The backbone of the adsorbent cylindrical bodies was prepared by polymerization of methacrylic acid and poly(ethylene glycol) diacrylate at sub-zero temperatures. Grafting was performed employing glycidyl methacrylate and a chemical initiator, cerium ammonium nitrate. The degree of grafting was adjusted by modifying the concentration of the initiator in the reaction mixture to a range of values (23, 39, 62, 89, and 105%). Further, the pendant epoxy-groups generated by the previous step were reacted to cation- and anion-exchanging moieties utilizing known chemical routes. Infrared spectroscopy studies confirmed the incorporation of epoxy and ion-exchanger groups to the backbone material. Optimized materials were tested for chromatography applications with model proteins; the dynamic binding capacity, as recorded at 10% breakthrough and 2.0 × 10(-4) m/s superficial velocity, were 350 and 58 mg/g for the cation-exchanger and the anion-exchanger material, respectively. These results may indicate that long tentacle-type polymer brushes were formed during grafting therefore increasing the ability of the megaporous body to efficiently capture macromolecules. PMID:23401432

Bibi, Noor Shad; Fernández-Lahore, Marcelo

2013-03-07

185

SEPARATION OF RADIUM AND BARIUM BY ION EXCHANGE ELUTION  

Microsoft Academic Search

Radium can be separated from barium-radium mixtures in ratios as high as ; 4440to 1 by a single elution from a cation exchange resin. Bariuim elution ; characteristics from Dowex 50 resin, position of elution maxima, and maximum ; barium loadings are correlated with citrate concentration and pH by the use of ; citrate complex equilibria, Ammonium citrate, 0.32M at

W. H. Power; H. W. Kirby; W. C. McCluggage; G. D. Nelson; J. H. Jr. Payne

1959-01-01

186

Ion exchange and surface charge on montmorillonite clay  

SciTech Connect

An ion-exchange model originally developed for pure oxides prepared in the laboratory is extended to study of ion exchange and surface charge on a naturally occurring montmorillonite clay. The range of surface charges measured for montmorillonite with various electrolyte solutions and clay pretreatments is within the range of those measured for a wide variety of oxides prepared in the laboratory, including MnO{sub 2}-IC1, MnO{sub 2}-IC12, MnO{sub 2}-IC22, titanium dioxide, ferric oxide, and aluminum oxide. In addition, fitted parameter values for lateral interaction constants and equilibrium constants for the acid sites that characterize ion exchange on montmorillonite are on the same order of magnitude as those obtained for pure oxides. Surface charge of montmorillonite in sodium nitrate solution is measured to be approximately 15 to 25% greater than that measured between a pH of 4 and 9 in calcium chloride solution. This difference is attributed to the greater charge on the calcium (2{sup +}) ion; thus, its stronger electrostatic attraction to the acid hydroxyl site. An order of magnitude change in solids concentration (C{sub p}) can lead to a difference in measured net surface charge density of the same oxide sample of several orders of magnitude. This difference increases at higher pH, indicating the importance of reporting the corresponding C{sub p} at which experiments are conducted.

Sperry, J.M.; Peirce, J.J.

1999-05-01

187

Syntesis of lanthanum zirconate hydrosols by the ion exchange method  

Microsoft Academic Search

Ion exchange of LaCl3 and ZrOCl2 aqueous solutions with anion-exchanger AV-17-8 was used to synthesize finely dispersed hydrosol of amorphous lanthanum zirconate La2Zr2O7. Heat treatment of dried La2Zr2O7 hydrosols at 700°C and 1100°C resulted in the formation of powders with fluorite and pyrochlore type structures, respectively. Epitaxial La2Zr2O7 films were obtained on SrTiO3 (001) single crystals. The substrate has an

E. A. Bovina; J. V. Tarasova; F. Kh Chibirova

2011-01-01

188

Syntesis of lanthanum zirconate hydrosols by the ion exchange method  

NASA Astrophysics Data System (ADS)

Ion exchange of LaCl3 and ZrOCl2 aqueous solutions with anion-exchanger AV-17-8 was used to synthesize finely dispersed hydrosol of amorphous lanthanum zirconate La2Zr2O7. Heat treatment of dried La2Zr2O7 hydrosols at 700°C and 1100°C resulted in the formation of powders with fluorite and pyrochlore type structures, respectively. Epitaxial La2Zr2O7 films were obtained on SrTiO3 (001) single crystals. The substrate has an influence on the lanthanum zirconate crystal orientation, as well as strong inhibitory effect on sintering processes.

Bovina, E. A.; Tarasova, J. V.; Chibirova, F. Kh

2011-04-01

189

Problem of describing the equilibrium during the dissolving of precipitates by ion-exchange resins  

Microsoft Academic Search

1.Different variations of dissolving the 1,1-charge precipitate of difficultly soluble substances, using either one ion exchanger or a mixed bed of ion exchangers, were discussed.2.Appropriate equations were derived, which made it possible to calculate the amount of ion exchangers required to completely dissolve the precipitate, and a comparative study of them was made.

A. V. Nikolaev; V. L. Bogatyrev

1971-01-01

190

Ion Exchange Media for Reduction of Liquid Radwaste in Commercial Power Plants  

Microsoft Academic Search

Ion exchange resins currently make up as much as one-half of all radioactive waste generated by commercial nuclear power plants. A major challenge is reduction of the quantity of ion exchange media requiring disposal. Although the amount of spent ion exchange resins disposed has decreased year after year, a new urgency has arisen with the pending closure of a major

P. A. Yarnell; A. Tavares

2008-01-01

191

SEPARATION OP ZIRCONIUM \\/IV\\/ FROM HAFNIUM \\/IV\\/ ON VARIOUS TYPES OF SELECTIVE ION-EXCHANGERS  

Microsoft Academic Search

Results of the studies on separation of hefnium \\/IV\\/ from zirconium \\/IV\\/ by frontal analysis on chelating ion-exchangers of different types have been presented. The phosphonic ion-exchanger Duolite ES-63 proved to be the best in zirconium sulphate purification from hafnium \\/IV\\/ among the examined chelating ion-exchangers.

Z. HUBICKI

1988-01-01

192

Co[sup 2+] ion exchange with NaY  

SciTech Connect

Co[sup 2+] ion exchange from aqueous cobalt chloride-sodium chloride solutions with NaY zeolite has been investigated. The effect of contact time on the sorption of Co[sup 2+] by dehydrated Y zeolite at 150[degrees]C is unusual. A fast sorption uptake is observed in which 1.73 mequiv/g of zeolite of Na[sup +] ions is replaced by cobalt ions, followed by a desorption process where the uptake decreases to 1.56 mequiv/g of zeolite. This behavior is explained by the location and coordination of cobalt in Y zeolite sites. It is suggested that the maximum uptake corresponds to cobalt ions being simultaneously in two sites; tetrahedrally coordinated in the sodalite units and octahedrally coordinated in the large cavities. It is also suggested that the desorption process is a consequence of a reaction between Cl[sup [minus

Garcia, I.; Solache-Rios, M.; Bulbulian, S. (Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico)); Bosch, P. (Instituto Nacional de Investigaciones Nucleares, Mexico City (Mexico) Universidad Autonoma Metropolitana, Iztapalapa (Mexico))

1993-02-11

193

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

USGS Publications Warehouse

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

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

2004-01-01

194

Method for permanently storing radioactive ion exchanger resins  

SciTech Connect

A method is claimed for forming a hardened product containing a radioactive ion exchanger resin in a condition for permanent, noncontaminating storage, by the steps of: providing, before fixing, a mass of such ion exchanger resin saturated in water, the resin being at least one resin selected from the group consisting of spherical resins and powdered resins; mixing the resin mass, with stirring, with a blast furnace cement having a composition which causes it to exhibit slow initial hardening, high sulfate resistance and low hydration heat and with a quantity of additional water equal in weight to 20% to 40% of the weight of the blast furnace cement; and allowing the resulting mixture to harden at room temperature.

Kunze, S.; Eden, G.; Koster, R.

1984-11-20

195

Reuse system for powdered ion-exchange resins  

SciTech Connect

A reuse system has been developed for powdered ion-exchange resins generated from nuclear power plants in order to reduce their waste volume. The system consists of: 1. crud removal from resins; 2. decomposition of flocks (flocculated resins); 3. resin separation into cation and anion types; 4. regeneration of each type. The most important points in this system are items 2 and 3, because generally resins flocculate too tightly to separate easily. By combined usage of a strong electrolyte (15 wt% NaOH solution) and a dual-basket-type centrifuge, spent powdered resins can be separated with an efficiency of 95% and regenerated for another use. The waste volume can be reduced to one-half after four reuse cycles, with a decrease in the ion-exchange capacity of only 5%.

Funabashi, K.; Fukasawa, T.; Kawamura, F.; Yusa, H.; Kikuchi, M.; Sasaki, N.; Yamadera, T.

1986-05-01

196

Switch to an advanced ion exchange resin cuts boiler costs  

SciTech Connect

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

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

1994-10-01

197

Cyanide recycling using strong-base ion-exchange resins  

NASA Astrophysics Data System (ADS)

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

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

1998-10-01

198

Controlled oxidative protein refolding using an ion-exchange column  

Microsoft Academic Search

Column-based refolding of complex and highly disulfide-bonded proteins simplifies protein renaturation at both preparative and process scale by integrating and automating a number of operations commonly used in dilution refolding. Bovine serum albumin (BSA) was used as a model protein for refolding and oxido-shuffling on an ion-exchange column to give a refolding yield of 55% after 40h incubation. Successful on-column

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

2005-01-01

199

Ion exchange and adsorption on low rank coals for liquefaction  

SciTech Connect

The objectives of this program involve the study of the catalysis of liquefaction of low rank coals. Ion exchange and adsorption techniques are being used or modified to incorporate catalytically active metals into coal samples. Relative oil yields will be determined by Sandia National Laboratory and PETC collaborators to establish the effectiveness of the catalyst incorporation techniques. This report describes work done over the past 12 months of an on-going project.

Vorres, K.S.

1995-08-01

200

Enhanced coagulation using a magnetic ion exchange resin  

Microsoft Academic Search

The objective of this investigation was to examine the effectiveness of a magnetic ion exchange resin (MIEX®) to enhance the coagulation of disinfection by-product precursors in nine surface waters, each representing a different element of the USEPA's 3×3 enhanced coagulation matrix. The effect of MIEX-pretreatment on the requisite alum dose needed for subsequent coagulation of turbidity was also evaluated.Enhanced coagulation

Philip C. Singer; Katya Bilyk

2002-01-01

201

Explosion hazards of ion exchange resin mixed with perchloric acid  

Microsoft Academic Search

On January 21, 2003, an explosion occurred while ion exchange resin (IER) was being used to separate impurities from uranium\\u000a solution. To clarify the cause of the accident and go\\/no-go criteria of the explosion, elemental analysis of the IER, DSC\\u000a analysis, and SIKAREX analysis (a screening tool for runaway reactions) were performed. Finally, experiments on the same scale\\u000a as the

Ken Okada; Miyako Akiyoshi; Atsumi Miyake; Terushige Ogawa; Mitsuo Nomura; Takehiro Matsunaga

2009-01-01

202

Reflective integrated optical elements produced by ion exchange in glass.  

PubMed

The use of total reflection at the boundary between the guiding region and the substrate (or another guiding region) to implement waveguide achromatic elements is discussed. Two geometries of the boundary, parabolic and elliptical, are proposed and analyzed. The parabolic boundary was fabricated by selective ion exchange, and both its focusing capabilities and the compatibility of its numerical aperture with optical fibers are demonstrated. PMID:18286138

Prieto, X; Liñares, J

1998-09-20

203

An Empirical Formula from Ion Exchange Chromatography and Colorimetry  

Microsoft Academic Search

Experimental determination of the empirical formula for sodium salicylate, Nax(C7H5O3)y, using colorimetry and cation exchange. A Beer's Law plot is prepared for salicylate using 0.0050 M salicylic acid solution. Colorimetric analysis is performed on the salicylate ion in the form of an aqueous ferric complex, which is intensely violet-red, using a simple, inexpensive colorimeter constructed from readily available electronic parts

Steven D. Johnson

1996-01-01

204

Pellicular ion exchange resins based on divinylbenzene and 2-vinylpyridine  

Microsoft Academic Search

A semi-suspension polymerization process was used in this work in order to prepare ion exchange pellicular resins. This technique allowed us to produce cores of polydivinylbenzene or poly(divinylbenzene-co-2-vinylpyridine) with narrow particle size distribution. The shell structure was formed by a porous thin layer of a functional polymer based on poly(divinylbenzene-co-2-vinylpyridine) grafted to the core. The characterization of cores and pellicular

F. M. B Coutinho; D. L Carvalho; M. L La Torre Aponte; C. C. R Barbosa

2001-01-01

205

Continuous ion exchange separation of zirconium and hafnium  

Microsoft Academic Search

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

J. M. Begovich; W. G. Sisson

1981-01-01

206

Synthesis and Characterization of Molecularly Imprinted Uranyl Ion Exchange Resins  

Microsoft Academic Search

Ion exchange resins with enhanced capacity and selectivity for UO2 have been prepared using the molecular imprinting method. The imprinted structure was introduced by copolymerization of styrene with uranyl vinylbenzoate in the presence of divinylbenzene as the cross?linking agent. The polymerization was carried out in bulk with free?radical initiation using 2?methoxyethanol as a solvent and porogen. Upon removal of the

Anael Kimaro; Lisa A. Kelly; George M. Murray

2005-01-01

207

Ion exchange extraction of heavy metals from wastewater sludges.  

PubMed

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

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

2004-01-01

208

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

SciTech Connect

'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.'

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

1998-06-01

209

Ion-optical studies for improved ion transmission in multistage isotope-ratio mass spectrometers  

SciTech Connect

Theoretical and experimental ion-optical studies of multistage isotope-ratio mass spectrometers were conducted to determine what improvement in ion transmission efficiency might be attainable through design changes. The computer program GIOS (General Ion Optical Systems) was used to perform theoretical calculations of focusing properties and ion transmission efficiency. Actual transmission through multiple-sector instruments was determined from measurements of the ion beam vertical profile at the focus of each stage. For existing mass spectrometers with tandem magnets of normal geometry, our studies determined a feasible design change that significantly increases ion transmission through the analyzer. The use of a cylindrical einzel lens or an electrostatic quadrupole lens near the focal point between the magnets provides vertical focusing of the ion beam to achieve the improved transmission. We also established a new mass spectrometer design that give 100% transmission through tandem magnetic analyzers and through a third-stage electrostatic analyzer without the use of an intermediate focusing lens. Non-normal magnetic field boundaries provide ion beam focusing in the vertical plant to achieve this complete transmission. 19 refs., 27 figs., 3 tabs.

Stoffels, J.J. (Pacific Northwest Lab., Richland, WA (United States)); Laue, H.J. (Purdue Univ., Lafayette, IN (United States))

1991-10-01

210

Kinetics of liquid-solid ion-exchange reactions of transition metal ions in tin(IV) phosphate  

NASA Astrophysics Data System (ADS)

A simple approach to liquid-solid ion exchange kinetics of Cu2+, Zn2+, Cd2+, Co2+ ions in tin(IV) phosphate under different conditions of temperature, exchange ion concentration, and the particle size of the exchanger has been reported. The kinetics were controlled by particle diffusion and the t1/2 law operated to about 65-75% of exchange. The diffusion coefficients and activation energies were calculated. The activation energies of Cu2+ and Co2+ ions were found to be low when compared with Zn2+ and Cd2+ ions due to Jahn-Teller distortion.

Thind, Pritam S.; Gandhi, Jatinder S.

1985-11-01

211

Charge exchange measurements with an x-ray calorimeter at an electron beam ion trap  

NASA Astrophysics Data System (ADS)

We present K-shell x-ray spectra of highly ionized Mg acquired with the EBIT calorimeter spectrometer at a resolution of 4.5 eV in charge exchange recombination experiments using the LLNL EBIT-I electron beam ion trap. We measured the Doppler width of Mg11+ Ly? in the same experiments using a high resolution crystal spectrometer, giving an estimate of the ion temperature. We find hardness ratios for Mg11+ ranging from 0.6 to 1.6, depending on the neutral gas target. In most of the experiments, the ion temperature was ˜ 10-15 eV?amu-1, indicating that the variations in hardness ratio are intrinsic to the choice of neutral target gas, and are not simply a consequence of variations in the collision velocity resulting from evaporative cooling of the trapped ions. The spectral variations show that high resolution x-ray spectroscopy is highly diagnostic of charge exchange reactions, but requires well-developed theory to interpret.

Leutenegger, Maurice A.; Betancourt-Martinez, Gabriele L.; Beiersdorfer, Peter; Brown, Gregory V.; Kelley, Richard L.; Kilbourne, Caroline A.; Porter, F. Scott

2013-09-01

212

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

Microsoft Academic Search

The scope of this study was the removal of ammonium by ion exchange from simulated wastewater. The study looks at the effect of organics upon ammonium ion exchange equilibrium uptake. The ion exchangers included a natural zeolite clinoptilolite, and two polymeric exchangers, Dowex 50w-x8, and Purolite MN500. The organic compounds studied included citric acid and a number of proteins. The

T. C. Jorgensen; L. R. Weatherley

2003-01-01

213

Indirect UV detection-ion-exclusion/cation-exchange chromatography of common inorganic ions with sulfosalicylic acid eluent.  

PubMed

Herein, we describe indirect UV detection-ion-exclusion/cation-exchange chromatography (IEC/CEC) on a weakly acidic cation-exchange resin in the H(+)-form (TSKgel Super IC-A/C) using sulfosalicylic acid as the eluent. The goal of the study was to characterize the peaks detected by UV detector. The peak directions of analyte ions in UV at 315 nm were negative because the molar absorbance coefficients of analyte anions and cations were lower than that of the sulfosalicylic acid eluent. Good chromatographic resolution and high signal-to-noise ratios of analyte ions were obtained for the separations performed using 1.1 mM sulfosalicylic acid and 1.5 mM 18-crown-6 as the eluent. The relative standard deviations (RSDs) of the peak areas ranged from 0.6 to 4.9%. Lower detection limits of the analytes were achieved using indirect UV detection at 315 nm (0.23 - 0.98 ?M) than those obtained with conductometric detection (CD) (0.61 - 2.1 ?M) under the optimized elution conditions. The calibration curves were linear in the range from 0.01 to 1.0 mM except for Cl(-), which was from 0.02 to 2.0 mM. The present method was successfully applied to determine common inorganic ions in a pond water sample. PMID:23303096

Kozaki, Daisuke; Mori, Masanobu; Nakatani, Nobutake; Arai, Kaori; Masuno, Tomoe; Koseki, Masakazu; Itabashi, Hideyuki; Tanaka, Kazuhiko

2013-01-01

214

Improvement of drug loading onto ion exchange resin by cyclodextrin inclusion complex.  

PubMed

Context: Ion exchange resins have ability to exchange their counter ions for ionized drug in the surrounding medium, yielding "drug resin complex." Cyclodextrin can be applied for enhancement of drug solubility and stability. Objective: Cyclodextrin inclusion complex of poorly water-soluble NSAIDs, i.e. meloxicam and piroxicam, was characterized and its novel application for improving drug loading onto an anionic exchange resin, i.e. Dowex(®) 1×2, was investigated. Methods: ?-cyclodextrin (?-CD) and hydroxypropyl ?-cyclodextrin (HP-?-CD) were used for the preparation of inclusion complex with drugs in solution state at various pH. The inclusion complex was characterized by phase solubility, continuous variation, spectroscopic and electrochemistry methods. Then, the drug with and without cyclodextrin were equilibrated with resin at 1:1 and 1:2 weight ratio of drug and resin. Results and discussion: Solubility of the drugs was found to increase with increasing cyclodextrin concentration and pH. The increased solubility was explained predominantly due to the formation of inclusion complex at low pH and the increased ionization of drug at high pH. According to characterization studies, the inclusion complex was successfully formed with a 1:1 stoichiometry. The presence of cyclodextrin in the loading solution resulted in the improvement of drug loading onto resin. Conclusions: Enhancing drug loading onto ion-exchange resin via the formation of cyclodextrin inclusion complex is usable in the development of ion-exchange based drug delivery systems, which will beneficially reduce the use of harmful acidic or basic and organic chemicals. PMID:23078590

Samprasit, Wipada; Rojanarata, Theerasak; Akkaramongkolporn, Prasert; Ngawhirunpat, Tanasait; Sila-On, Warisada; Opanasopit, Praneet

2012-10-19

215

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

SciTech Connect

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

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

2012-06-19

216

Origin of Selectivity in Tunnel Type Inorganic Ion Exchangers  

SciTech Connect

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

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

2004-03-29

217

Performance evaluation of ion-exchange chromatography in capillary format.  

PubMed

The performance of a recently introduced capillary ion-exchange chromatography system was explored. Experiments were conducted in isocratic mode with a commercial capillary anion-exchange column (id = 0.4 mm, L = 15 cm) using a five-anion standard mixture. The achieved results were compared to the performance of a standard bore ion-exchange system (id = 4 mm, L = 15 cm), which was considered as a reference. The first-generation capillary columns exhibited a minimal reduced plate-height value below two witnessing a good packing quality and system performance. However, compared to the standard bore system the capillary system displayed an increased apparent C-term which could be due to a difference in packing morphology and/or possible external band-broadening contributions. For fast separations, the standard bore system outperformed the capillary system, while for complex separations both systems performed nearly equally well. In addition, the retention characteristics of the capillary system were investigated. To illustrate the suitability of the capillary system, the analysis of real-world water samples originating from two local Belgian rivers was demonstrated. PMID:23125111

Eghbali, Hamed; Bruggink, Cees; Agroskin, Yury; Pohl, Christopher A; Eeltink, Sebastiaan

2012-11-02

218

Continuous ion exchange separation of zirconium and hafnium  

SciTech Connect

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.

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

1981-01-01

219

Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR  

NASA Astrophysics Data System (ADS)

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

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

2008-10-01

220

Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR  

SciTech Connect

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

Delabie, E.; Jaspers, R. J. E.; Hellermann, M. G. von [FOM-Rijnhuizen, EURATOM-FOM, NL-3430 BE Nieuwegein (Netherlands); Nielsen, S. K. [Association EURATOM-Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Marchuk, O. [Forschungszentrum Juelich, EURATOM-FZJ, D-52424 Juelich (Germany)

2008-10-15

221

Calculation of stopping power ratios for carbon ion dosimetry.  

PubMed

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

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

2006-04-19

222

Assessment of cadmium in aquatic sediment using dialysis samplers with ion-exchange-resin collection  

SciTech Connect

Simultaneously extracted metals (SEM) and acid volatile sulfide (AVS) show the potential for toxicity on the basis of their ratio. Accordingly, the authors spiked cadmium in a range for which Cd/AVS ratios were from 0.2 to 10 in the sediment with its weight about 8 kg in each batch. Dialysis samplers with a cation ion-exchange resin (Dowex 50W-X4) collection were used in a laboratory for the determination of free cadmium concentrations in pore water of the collected sediment. When equilibrium was reached among cadmium in pore water, sediment, and ion-exchange resin, cadmium exchanged onto resin phase was regenerated with 1 N hydrochloric acid (OPTIMA grade) and determined using an atomic absorption spectrophotometer (Zeeman 5000) with a graphite furnace accessory. Cadmium determined using the dialysis sampler is considered as free cadmium which is related to the metal bioavailability toward aquatic biota. The developed methodology provides a new technique for assessment of free metal in aquatic sediment systems.

Shi, B. [Kimberly-Clark Corp., Neenah, WI (United States). Environmental Technology; Allen, H.E. [Univ. of Delaware, Newark, DE (United States). Dept. of Civil and Environmental Engineering; Desnoyers, C. [ERM Program Management Co., Exton, PA (United States)

1998-05-01

223

Removal of THM precursors by coagulation or ion exchange.  

PubMed

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

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

2002-12-01

224

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

Microsoft Academic Search

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

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

1985-01-01

225

HEAT TRANSFER ANALYSIS FOR ION-EXCHANGE COLUMN SYSTEM  

SciTech Connect

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

Lee, S.; King, W.

2011-05-23

226

Vitrification of cesium-contaminated organic ion exchange resin  

SciTech Connect

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.

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

1994-08-01

227

Studies of ion-exchange resin complex of chloroquine phosphate.  

PubMed

High-potency adsorbates of chloroquine phosphate (CQP) were prepared by the batch method using a polyacrylic acid ion-exchange resin. Taste evaluation of the adsorbates shows significant masking of the bitterness of the drug. The complex formation was complete at pH 6.0. Stability studies at 37 degrees C, 45 degrees C, and 60 degrees C indicated that the complex was stable at all conditions for 1 month. In vitro release studies revealed complete drug elution from the complex at pH 1.2 and 2.0. PMID:10872097

Agarwal, R; Mittal, R; Singh, A

2000-07-01

228

Preparation and evaluation of microencapsulated ion-exchange resin beads.  

PubMed

Ion-exchange resin beads in the benzoate form were coated by several microencapsulation techniques to alter and improve characteristics, especially the control of drug release, of this type of drug delivery system. The most successful techniques included polymer-polymer interaction, temperature change, and nonsolvent addition. The microencapsulated beads then were studied with respect to the release rate of the organic anion to determine the effects of microencapsulation. The release rate of the organic anion could be controlled over a wide range, depending on the encapsulating material characteristics. Factors affecting the extent and rate of release as result of microencapsulation are discussed. PMID:423093

Motycka, S; Nairn, J G

1979-02-01

229

Selective removal of the heavy metal ions from waters and industrial wastewaters by ion-exchange method  

Microsoft Academic Search

By ion exchange undesirable ions are replaced by others which don't contribute to contamination of the environment. The method is technologically simple and enables efficient removal of even traces of impurities from solutions. Examples of selective removal of heavy metal ions by ion-exchange are presented. They include removal of Pb(II), Hg(II), Cd(II), Ni(II), V(IV,V), Cr(III,VI), Cu(II) and Zn(II) from water

Z. Hubicki; P. Podko?cielny; E. Robens

2004-01-01

230

ION EXCHANGE SUBSTANCES BY SAPONIFICATION OF ALLYL PHOSPHATE POLYMERS  

DOEpatents

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

Kennedy, J.

1959-04-14

231

Electrically switched cesium ion exchange. FY 1996 annual report  

SciTech Connect

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

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

1996-12-01

232

THE ION-INDUCED CHARGE-EXCHANGE X-RAY EMISSION OF THE JOVIAN AURORAS: MAGNETOSPHERIC OR SOLAR WIND ORIGIN?  

SciTech Connect

A new and more comprehensive model of charge-exchange induced X-ray emission, due to ions precipitating into the Jovian atmosphere near the poles, has been used to analyze spectral observations made by the Chandra X-ray Observatory. The model includes for the first time carbon ions, in addition to the oxygen and sulfur ions previously considered, in order to account for possible ion origins from both the solar wind and the Jovian magnetosphere. By comparing the model spectra with newly reprocessed Chandra observations, we conclude that carbon ion emission provides a negligible contribution, suggesting that solar wind ions are not responsible for the observed polar X-rays. In addition, results of the model fits to observations support the previously estimated seeding kinetic energies of the precipitating ions ({approx}0.7-2 MeV u{sup -1}), but infer a different relative sulfur-to-oxygen abundance ratio for these Chandra observations.

Hui Yawei; Schultz, David R. [Physics Division, Oak Ridge National Laboratory Bldg. 6010, Oak Ridge, TN 37831 (United States); Kharchenko, Vasili A. [Physics Department, University of Connecticut 2152 Hillside Road, U-3046, Storrs, CT 06269 (United States); Stancil, Phillip C. [Department of Physics and Astronomy and the Center for Simulational Physics, University of Georgia, Athens, GA 30602 (United States); Cravens, Thomas E. [Department of Physics and Astronomy, University of Kansas 1251 Wescoe Hall Drive, Lawrence, KS 66045 (United States); Lisse, Carey M. [Johns Hopkins University Applied Physics Laboratory SD/SRE, MP3-E167, 11100 Johns Hopkins Road, Laurel MD 20723 (United States); Dalgarno, Alexander [Harvard-Smithsonian Center for Astrophysics 60 Garden Street, Cambridge, MA 02138 (United States)], E-mail: huiy@ornl.gov, E-mail: schultzd@ornl.gov, E-mail: kharchenko@phys.uconn.edu, E-mail: stancil@physast.uga.edu, E-mail: cravens@ku.edu, E-mail: carey.lisse@jhuapl.edu, E-mail: adalgarno@cfa.harvard.edu

2009-09-10

233

The Ion-induced Charge-exchange X-ray Emission of the Jovian Auroras: Magnetospheric or Solar Wind Origin?  

SciTech Connect

A new and more comprehensive model of charge-exchange induced X-ray emission, due to ions precipitating into the Jovian atmosphere near the poles, has been used to analyze spectral observations made by the Chandra X-ray Observatory. The model includes for the first time carbon ions, in addition to the oxygen and sulfur ions previously considered, in order to account for possible ion origins from both the solar wind and the Jovian magnetosphere. By comparing the model spectra with newly reprocessed Chandra observations, we conclude that carbon ion emission provides a negligible contribution, suggesting that solar wind ions are not responsible for the observed polar X-rays. In addition, results of the model fits to observations support the previously estimated seeding kinetic energies of the precipitating ions ( 0.7-2 MeV/u), but infer a different relative sulfur to oxygen abundance ratio for these Chandra observations.

Hui, Yawei [ORNL; Schultz, David Robert [ORNL; Kharchenko, Vasili A [ORNL; Stancil, Phillip C. [University of Georgia, Athens, GA; Cravens, Thomas E. E. [University of Kansas; Lisse, Carey M. [Johns Hopkins University; Dalgarno, A. [Harvard-Smithsonian Center for Astrophysics

2009-01-01

234

Kinetics of sorption of niobium ions by anion-exchangers from mixed chloride-fluoride solutions  

Microsoft Academic Search

The authors showed earlier on the basis of experimental and calculated data obtained in studies of ion-exchange equilibrium that the sorbability and composition of sorbed niobium ions are determined by the content of hydrofluoric acid in mixed chloride-fluoride solutions. Variation of the ionic state of niobium in these solutions should also influence the rate of ion exchange. In this communication

V. N. Rychkov; V. S. Pakholkov; L. D. Kuznetsova

1987-01-01

235

EVALUATION OF SYNTHETIC INORGANIC ION EXCHANGERS FOR CESIUM AND STRONTIUM REMOVAL FROM CONTAMINATED GROUNDWATER AND WASTEWATER  

Microsoft Academic Search

The ion exchange testing of 30 synthetic adsorbents including layered and framework polyvalent metal silicates and phosphates, as well as amorphous exchangers was carried out. Their selectivity to alkali and alkaline earth metal cations in individual and complex solutions was determined. Several exchangers were found to have high selectivity for cesium and strontium. These exchangers are sodium phlogopite, layered sodium

Anatoly I. Bortun; Lyudmila N. Bortun; Abraham Clearfield

1997-01-01

236

Selective ion electrode measurements of chloride concentrations in the determination of cation exchange capacities of soils  

Microsoft Academic Search

The determination of chloride ion in soil extracts for cation exchange capacity in the presence of ammonium ions of nearly equal concentration (5 x 10 M) and excess sodium sulphate (0.5 M) by an Orion solid state selective ion electrode is reported. Ammonium ions were found to interfere by reducing the determined value of the chloride ion by up to

R. St. C. Smart; A. D. Thomas; D. P. Drover

1974-01-01

237

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

USGS Publications Warehouse

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

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

2000-01-01

238

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

SciTech Connect

Approximately 73 m{sup 3} 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 extraction of PCB surrogates from simulant K Basin sludge is also given.

Schmidt, A.J.; Klinger, G.S.; Bredt, P.R.

1999-04-10

239

The role of humic non-exchangeable binding in the promotion of metal ion transport in groundwaters in the environment.  

PubMed

Metal ions form strong complexes with humic substances. When the metal ion is first complexed by humic material, it is bound in an 'exchangeable' mode. The metal ion in this fraction is strongly bound, however, if the metal-humic complex encounters a stronger binding site on a surface, then the metal ion may dissociate from the humic substance and be immobilised. However, over time, exchangeably-bound metal may transfer to a 'non-exchangeable' mode. Transfer into this mode and dissociation from it are slow, regardless of the strength of the competing sink, and so immobilisation may be hindered. A series of coupled chemical transport calculations has been performed to investigate the likely effects of non-exchangeable binding upon the transport of metal ions in the environment. The calculations show that metal in the non-exchangeable mode will have a significantly higher mobility than that in the exchangeable mode. The critical factor is the ratio of the non-exchangeable first-order dissociation rate constant and the residence time in the groundwater column, metal ion mobility increasing with decreasing rate constant. A second series of calculations has investigated the effect of the sorption to surfaces of humic/metal complexes on the transport of the non-exchangeably bound metal. It was found that such sorption may reduce mobility, depending upon the humic fraction to which the metal ion is bound. For the more weakly sorbing humic fractions, under ambient conditions (humic concentration etc.) the non-exchangeable fraction may still transport significantly. However, for the more strongly sorbed fractions, the non-exchangeable fraction has little effect upon mobility. In addition to direct retardation, sorption also increases the residence time of the non-exchangeable fraction, giving more time for dissociation and immobilisation. The non-exchangeable dissociation reaction, and the sorption reaction have been classified in terms of two Damkohler numbers, which can be used to determine the importance of chemical kinetics during transport calculations. These numbers have been used to develop a set of rules that determine when full chemical kinetic calculations are required for a reliable prediction, and when equilibrium may be assumed, or when the reactions are sufficiently slow that they may be ignored completely. PMID:17410308

Bryan, Nick D; Jones, Dominic L M; Keepax, Rose E; Farrelly, Dean H; Abrahamsen, Liam G; Pitois, Aurelien; Ivanov, Peter; Warwick, Peter; Evans, Nick

2007-03-01

240

Ion exchangers in radioactive waste management: natural Iranian zeolites.  

PubMed

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 (131)I, (99)Mo, (153)Sm, (140)La and (147)Nd. All the zeolite samples used in this study had extremely high absorption value towards (140)La; clinoptolite from Mianeh and analsite from Ghalehkhargoshi showed good absorption for (147)Nd; clinoptolite from Semnan and clinoptolite from Firozkoh showed high absorption for (153)Sm; mesolite from Arababad Tabas showed good absorption for (99)Mo; and finally mesolite from Arababad Tabas, clinoptolite from Semnan and clinoptolite from Firozkoh could be used to selectively absorb (131)I 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. PMID:16099667

Nilchi, A; Maalek, B; Khanchi, A; Ghanadi Maragheh, M; Bagheri, A; Savoji, K

2005-08-15

241

Low-level liquid waste decontamination by ion exchange  

SciTech Connect

Improved processes are being developed to treat contaminated liquid wastes that have been and continue to be generated at Oak Ridge National Laboratory using both inorganic and organic ion-exchange methods. Nickel and cobalt hexacyanoferrate(2) compounds are extremely selective for Cs removal, with distribution coefficients in excess of 10{sup 6} and remarkable insensitivity to competition from Na and K. They tend to lose effectiveness at pH >{approximately}11, but some formulations are useful for limited periods of time up to pH {approximately}13. Sodium titanate is selective for Sr removal at high pH. 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 {approximately}12.5. It was much less effective for Sr removal, which was limited by competition from Na. 8 refs., 4 figs., 9 tabs.

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

1990-01-01

242

Purification of lithium salts by CSA continuous countercurrent ion exchange  

SciTech Connect

A Continuous Countercurrent Ion Exchange (CCIX) process was developed for extraction of low levels of sodium, potassium, iron, and nickel from strong solutions of lithium chloride and lithium hydroxide. This study was done on a two-inch diameter CSA, Inc. CCIX pilot unit. A standard 8% cross-linked cation exchange resin was used. The feed was either 2[und M] LiCl or 2[und M] LiOH. The trace levels of contaminants had a slightly higher affinity for the resin than lithium and extracted 90% or better. Residual lithium on the resin was scrubbed of with KOH to render a lithium loss of less than 1% in the waste. Contaminants were stripped from the resin with 3[und M] HCl. Zinc was one metal that was not extracted because it formed an anionic chloride complex. However zinc and certain other metals were extracted with high efficiency using strong-base type resin. Other resins are available for efficient extraction of many other metal contaminants, but the alkali metals, Na and K, were dependent on the CCIX common cation exchange system.

Higgins, I.R. (CSA, Inc., Oak Ridge, TN (United States))

1986-12-01

243

Computational Module for Charge Exchange and Ion Stripping in  

NASA Astrophysics Data System (ADS)

Stripping on background gases or plasma in heavy ion beam fusion chamber increases the charge state of the beam, and increases the diameter of the focus making the final focusing more complex. To model transport in the chamber, it is necessary to know the beam charge state evolution including charge exchange. In this paper, data mining of stripping cross section and charge exchange data from finished experiments, handbooks and calculations will be conducted as a first step. Followed are theoretical approaches to unsolved data especially for near-term experiments in HIF especially about multi electron stripping. Among frequently used theoretical approaches, the classical trajectory Monte Carlo (CTMC) calculation is simpler and can yield results close to quantum mechanical calculations. That's why we will apply CTMC approach here. In the theoretical approach, scaling law is needed in some case to widen the applications in higher energy range. After the data mining and theoretical calculations on stripping and charge exchange, a computational database will be developed followed by a subroutine for the electromagnetic plasma simulation code LSP's use and applications in near-term experiments and simulations in HIF. All the computational work and database building will be implemented using C++ language. Further work is supposed to serve future driver-scale experiments and simulations in HIF.

Wu, Linchun; Miley, George H.

2004-05-01

244

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

NASA Astrophysics Data System (ADS)

In the present investigation, 82Br radioactive isotope was used as a tracer to study the kinetics and mechanism of exchange reaction between an ion exchange resin and an external bromide ion solution. In an attempt to study the reversible bromide ion isotopic exchange reaction kinetics, it was expected that whether the initial step was the exchange of radioactive bromide ions from the solution into the ion exchange resin (forward reaction) or from the ion exchange resin into the solution (reverse reaction), two ion isotopic exchange reactions should occur simultaneously, which was further confirmed by the experimental specific reaction rates of 0.130 and 0.131 min-1, respectively. The results can be used to standardize process parameters so as to optimize the utilization of ion exchange resins in various industrial applications.

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

2007-11-01

245

Solidification in cement of ion-exchange resins from LOMI (Low Oxidation State Metal Ion) decontamination  

SciTech Connect

Chemical decontamination of operating nuclear power plants is performed to remove radioactive metal oxides from pipes and equipment thereby reducing the radiation exposure to personnel performing inspection and maintenance. The LOMI (Low Oxidation State Metal Ion) process is widely used to perform this decontamination. At the end of the decontamination operations, the chemicals remaining in solution are removed by ion exchange resins. The resins are subsequently solidified in metal liners using cement, transported and buried at an approved burial site. The work covered by this report was undertaken because of an incomplete solidification of the ion exchange resins. The details of the decontamination operations have been described. At the time the problem arose, a preliminary investigation led to the conclusion that the unsolidified resin resulted from inadequate mixing caused by the formation of hydrated gel. The purpose of this project was to develop an understanding of the variables affecting the formation of the gel and to devise methods to avoid its formation. Additionally, safe limits would be defined that would assure the complete solidification in cement of ion exchange resins used in LOMI chemical decontaminations. 5 refs., 3 figs., 6 tabs.

Not Available

1990-08-01

246

Ion exchange resins. (Latest citations from the US Patent bibliographic file with exemplary claims). Published Search  

SciTech Connect

The bibliography contains citations concerning preparation, regeneration, and applications of ion exchange resins. Applications include water and waste treatment; food processing; chemical recovery, separation, purification, and catalysis; desalination; and ore treatment and recovery. Methods are included for the processing of spent ion exchange resins and for protecting ion exchange resins from oxidation and chemical degradation. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1994-04-01

247

Comparison of inorganic ion exchange materials for removing cesium, strontium, and transuranic elements from K-basin water  

SciTech Connect

The work presented in this report was conducted by the Pacific Northwest National Laboratory (PNNL) under the Efficient Separations and Crosscutting Program (ESP), Office of Science and Technology, U.S. Department of Energy (DOE). The objective of this work was to investigate radionuclide uptake by several newly produced ion exchange materials under actual waste conditions, and to compare the performance of those materials with that of commercially available ion exchangers. The equilibrium uptake data presented in this report are useful for identifying potential materials that are capable of removing cesium and strontium from 105-KE Basin water. The data show the relative selectivities of the ion exchange materials under similar operating conditions. Additional flow studies are needed to predict material capacities and to develop complete ion exchange process flow sheets. The materials investigated in this study include commercially available ion exchangers such as IONSIV{reg_sign} IE-911 (manufactured by UOP), clinoptilolite (a naturally occurring zeolite), and materials produced on an experimental basis by AlliedSignal (biotites and nonatitanates), 3M (hexacyanoferrates), Selion Technologies, Inc. (hexacyanoferrates and titanates), and Texas A&M University (pharmacosiderites, biotites, and nonatitanates). In all, the performance of 14 ion exchange materials was evaluated at two solution-to-exchanger mass ratios (i.e., 10{sup 4} and 10{sup 5}) using actual 105-KE Basin water. Evaluation consisted of determining cesium and strontium batch distribution coefficients, loading, and decontamination factors. Actual 105-KE Basin water was obtained from a sample collected during the sludge dissolution work conducted by PNNL in FY 1996. This sample was taken from the bottom of the basin and contained significantly higher concentrations of the radioactive constituents than do samples taken from the top of the basin.

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

1997-10-01

248

The ion-exchange and electron-exchange properties of semicokes from the coals of the Kansk-Achinsk basin  

SciTech Connect

It has been found that, by the oxidation and heat treatment of semicokes from the coals of the Kansk-Achinsk basin, it is possible to obtain materials with ion- and electron-exchange properties approximating in their characteristics to well-known carbonaceous ion-exchangers such as those based on BAU activated charcoal. The possibility has been shown of the practical use of modified semicokes for purifying water.

Tarkovskaya, I.A.; Goba, V.E.; Nikolaeva, V.A.; Tomashevskaya, A.N.

1984-01-01

249

The separation of Zn and Cu using chelating ion exchangers and temperature variations  

SciTech Connect

This paper reports the results of a study on the ion-exchange equilibrium of Cu{sup 2+} and Zn{sup 2+} at different temperatures on chelating ion-exchange resins: Amberlite IRC-718 (iminodiacetic acid based functional groups), VPC-l (picolinic acid based) and thiourea-based resins. The separation factors and the conditional equilibrium constants of the ion-exchange reaction were determined in temperature range from 15 to 75 {degrees}C. An estimation of thermodynamic functions has also been carried out. Possibility of the separation of Cu and Zn mixture by dual temperature ion-exchange method has been demonstrated.

Zagorodni, A.A.; Muhammed, M.; Muiraviev, D.N. [Royal Inst. of Technology, Stockholm (Sweden)

1997-01-01

250

Extraction of metal ions sorbed on Mn(IV) oxides and CaCO 3 using ion exchange resins  

Microsoft Academic Search

The ability of ion exchange resins to promote release of metal ions (Cu, Ph, Cd or Zn) presorbed on different structural forms of Mn(IV) oxide or CaCO3 has been investigated using exchangers possessing different types of functional groups and charged in either the H+ or Na+ form. The exchanger uptake reflected the degree of soluble salt or labile complex displaced

J. Slavek; W. F. Pickering

1989-01-01

251

Removing thiocyanates from wastewater with pyridine and quinoline ion exchange resins  

SciTech Connect

The use of ion exchange resins for the treatment of coking plant wastewater has been investigated. Anion resins synthesized from chloromethylated styrene copolymer and divinylbenzene with pyridine and quinoline groups, appear promising for the removal of thiocyanate ions.

Lipunov, I.N.

1981-01-01

252

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

SciTech Connect

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

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

1993-03-01

253

The prospect for fuel ion ratio measurements in ITER by collective Thomson scattering  

NASA Astrophysics Data System (ADS)

We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT/nD, in ITER. Fuel ion ratio measurements will be important for plasma control and machine protection in ITER. Measurements of ion cyclotron structures in CTS spectra have been suggested as the basis for a new fuel ion ratio diagnostic which would be well suited for reactor environments and capable of providing spatially resolved measurements in the plasma core. Such measurements were demonstrated in recent experiments in the TEXTOR tokamak. Here we conduct a sensitivity study to investigate the potential measurement accuracy of a CTS fuel ion ratio diagnostic on ITER. The study identifies regions of parameter space in which CTS can be expected to provide useful information on plasma composition, and we find that a CTS fuel ion ratio diagnostic could meet the ITER measurement requirements for a standard ELMy H-mode discharge.

Stejner, M.; Korsholm, S. B.; Nielsen, S. K.; Salewski, M.; Bindslev, H.; Furtula, V.; Leipold, F.; Michelsen, P. K.; Meo, F.; Moseev, D.

2012-02-01

254

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

255

Mössbauer Effect and X-ray Photoelectron Characterization of Iron Oxide Nanoparticles Synthesized by Ion Exchange  

NASA Astrophysics Data System (ADS)

Three samples of iron oxide nanoparticles have been synthesized by ion exchanging in a sulfonated divinyl benzene polystyrene resin matrix. The first was prepared by ion exchanging an aqueous solution of FeCl2 within this matrix, the second by an aqueous solution of FeCl2 and FeCl3 in a 1:2 molar ratio, and the third by an aqueous solution of FeCl2 and CoCl2 in a 4:1 molar ratio. The samples were characterized by X-ray diffraction, transmission electron microscopy, Fe^57 Mössbauer spectroscopy, and X-ray photoelectron spectroscopy (XPS). The room temperature Mössbauer spectrum of the sample prepared by using the FeCl2 solution indicates a broad distribution of both particle size and blocking temperatures (T_B). In contrast, the spectrum for the sample prepared by mixing FeCl2 and FeCl3 consists only of a quadrupole doublet from room temperature down to 78 K, indicating a much narrower superparamagnetic particle size distribution with a TB below 78 K. Eventually at LHe temperatures the spectrum exhibits the two superimposed six line patterns. The Fe^57 Mössbauer results for the third sample are similar to the first sample. Further details on the particle size distribution and the relative amounts of the iron oxides phases from XRD and XPS studies will also be presented. *Permanent address: Kettering University, Flint, MI

Vaishnava, P. P.; McCullen, E.; Kroll, E.; Naik, R.; Wenger, L. E.; Suryanarayanan, R.; Tao, Qu; Boolchand, P.; Naik, V. M.

2003-03-01

256

Copper ion-exchanged channel waveguides optimization for optical trapping.  

PubMed

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

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

2013-05-30

257

Complex chromatid-isochromatid exchanges following irradiation with heavy ions?  

PubMed

We describe a peculiar and relatively rare type of chromosomal rearrangement induced in human peripheral lymphocytes that were ostensibly irradiated in G(0) phase of the cell cycle by accelerated heavy ions, and which, to the best of our knowledge, have not been previously described. The novel rearrangements which were detected using mFISH following exposure to 500 MeV/nucleon and 5 GeV/n 56Fe particles, but were not induced by either 137Cs gamma rays or 238Pu alpha particles, can alternatively be described as either complex chromatid-isochromatid or complex chromatid-chromosome exchanges. Different mechanisms potentially responsible for their formation are discussed. PMID:15162039

Loucas, B D; Eberle, R L; Durante, M; Cornforth, M N

2004-01-01

258

Recovery of very dilute acetic acid using ion exchange  

SciTech Connect

Acetic and related acids occur in many industrial wastewaters, often mixed with several other classes of organic compounds. Acetic acid can be recovered from 1% solutions using weakly basic ion exchange resins. The acid is adsorbed by the free-base form of the resin, which can then be eluted using a slurry of lime to give a solution of calcium acetate. This solution could either be evaporated to crystallize calcium acetate or reacted with sulfuric acid to form acetic acid and gypsum. Laboratory tests of the proposed process gave product solutions of 15--20% acetic acid using pure 1% acetic acid as feed. Some measurements using a typical industrial effluent gave similar recoveries and showed that there was no initial fouling of the resins.

Cloete, F.L.D.; Marais, A.P. [Univ. of Stellenbosch (South Africa). Dept. of Chemical Engineering

1995-07-01

259

Manifestation of exchange effects in heavy-ion interactions  

SciTech Connect

Three different approaches to taking into account exchange effects in heavy-ion collisions are studied. Within the first of them, the lowest eigenstates of the Hamiltonian are treated as forbidden states. In the second approach, the eigenstates of the normalization kernel of the resonating-group model that correspond to zero eigenvalues are treated as forbidden states. The third approach takes additionally into account semiforbidden states. The {sup 16}O + {sup 16}O system is considered. A hybrid approach that combines the methods of discrete and continuous mathematics is developed for calculating the widths of narrow resonance states. The resonance width calculated within the approach that takes into account semiforbidden states proves to be sharply different from the widths obtained within traditional approaches.

Igashov, S. Yu.; Tchuvil'sky, Yu. M., E-mail: tchuvl@nucl-th.sinp.msu.ru [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

2011-11-15

260

Isolation of natural products by ion-exchange methods.  

PubMed

The primary goal of many natural products chemists is to extract, isolate, and characterize specific analytes from complex plant, animal, microbial, and food matrices. To achieve this goal, they rely considerably on highly sophisticated and highly hyphenated modern instrumentation. Yet, the vast majority of modern instrumentation typically found in the laboratories of natural products chemists is founded on the simple principles of intermolecular forces to achieve separation. Ion-exchange chromatography (IEC) is, at heart, the most fundamental, and strongest, of these interactions and is considered a relatively inexpensive and effective medium in which to "clean-up" a sample. Additionally, IEC offers high recoveries of key analytes and offers the ability to modify the stationary and mobile phases in order to selectively "catch and release" compounds of interest. PMID:22367898

Dragull, Klaus; Beck, John J

2012-01-01

261

Electrodialysis-ion exchange for the separation of dissolved salts  

SciTech Connect

The Department of Energy generates and stores a significant quantity of low level, high level, and mixed wastes. As some of the DOE facilities are decontaminated and decommissioned, additional and possibly different forms of wastes will be generated. A significant portion of these wastes are aqueous streams containing acids, bases, and salts, or are wet solids containing inorganic salts. Some of these wastes are quite dilute solutions, whereas others contain large quantities of nitrates either in the form of dissolved salts or acids. Many of the wastes are also contaminated with heavy metals, radioactive products, or organics. Some of these wastes are in storage because a satisfactory treatment and disposal processes have not been developed. This report describes the process of electrodialysis-ion exchange (EDIX) for treating aqueous wastes streams consisting of nitrates, sodium, organics, heavy metals, and radioactive species.

Baroch, C.J.; Grant, P.J.

1995-12-31

262

PIC simulation study of the effect of ion to electron mass ratio on Ion beam driven instability and generation of ion holes  

NASA Astrophysics Data System (ADS)

Solitary wave structures with a lifetime of a few 'ms' and a scale width of 10~50 electron debye length have been observed in the magnetosphere. These relatively slow solitary waves have been considered as ion holes, which are suggested to be generated by ion beam driven instability. Previously, some particle simulations have shown that the ion holes are generated by ion beam driven instability. However, these simulations posed a problem that they used reduced ion to electron mass ratios to save computation time. It was assumed that ion and electron dynamics are sufficiently separated with the reduced mass ratios, but it was not clearly verified. In this study, we examine the effect of ion to electron mass ratios on the generation of ion holes by ion beam driven instability using one-dimensional electrostatic particle-in-cell simulation. Using the same plasma condition with one of the previous simulations we obtained almost same results when the same reduced ion to electron mass ratio was used. However, with the real ion to electron mass ratio ion holes were not generated. This implies that the previously suggested ion beam driven instability is strongly affected by the coupling between ions and electrons and the ion to electron mass ratio is important on the development of the instability. Also, this result suggests that the ion beam driven instability may not be the generation mechanism of the ion holes. We will discuss in detail the physical differences in the ion beam driven instability arising from the different ion to electron mass ratios.

Hong, J.; Lee, E.; Min, K. W.; Parks, G. K.

2011-12-01

263

Optimization of affinity and ion-exchange chromatographic processes for the purification of proteins.  

PubMed

This study documents several alternative approaches for the optimization of the ion-exchange and affinity chromatographic purification of proteins. In these approaches, the chromatographic process has been treated as a four-stage (adsorption, washing, elution, and regeneration) operation. Central to these investigations has been the elaboration of practical iterative procedures based on the use of theoretical models describing each of these stages. Predictions derived from these models have then been evaluated in terms of experimental data obtained using batch adsorption measurements in finite bath configurations and frontal breakthrough measurements with packed beds of different dimensions, containing nonporous and porous adsorbents of different selectivities and capacities for proteins. Commencing with the kinetic and distribution parameters derived from batch equilibrium measurements, the effect of the initial concentration of the target protein, the solid-liquid volume ratio, the superficial velocity and the column dimensions on the pressure drop, production rate, concentration profile, column utilization, and yield have been determined with packed beds. The potential of these iterative approaches to simplify the determination of key mass transfer and interaction parameters required for scale-up and economic optimization of chromatographic purifications of proteins has been examined using ion exchange, immobilized metal ion affinity, and triazine dye pseudo-affinity adsorbents of different selectivity and adsorption capacities. PMID:18629889

Mao, Q M; Hearn, M T

1996-10-20

264

Peptide Orientation Affects Selectivity in Ion-Exchange Chromatography  

PubMed Central

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

2010-01-01

265

Peptide Orientation Affects Selectivity in Ion-Exchange Chromatography  

SciTech Connect

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

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

2010-06-15

266

Immobilization of Acetobacter aceti on cellulose ion exchangers: adsorption isotherms  

SciTech Connect

The adsorptive behavior of cells of Acetobacter aceti, ATCC 23746, on DEAE-, TEAE-, and DEHPAE-cellulose ion exchangers in a modified Hoyer's medium at 30 degrees Centigrade was investigated. The maximum observed adsorption capacities varied from 46 to 64 mg dry wt/g resin. The Langmuir isotherm form was used to fit the data, since the cells formed a monolayer on the resin and exhibited saturation. The equilibrium constant in the Langmuir expression was qualitatively correlated with the surface charge density of the resin. The adsorption was also ''normalized'' by considering the ionic capacities of the resins. The exceptionally high normalized adsorption capacity of ECTEOLA-cellulose, 261 mg dry/meq, may be explained by an interaction between the cell wall and the polyglyceryl chains of the exchanging groups in addition to the electrostatic effects. The effect of pH on the bacterial adsorption capacity of ECTEOLA-, TEAE-, and phosphate-cellulose resins was studied and the pH of the bacteria was estimated to be 3.0. 17 references.

Bar, R.; Gainer, J.L.; Kirwan, D.J.

1986-08-01

267

Development of Electrically Switched Ion Exchange Process for Selective Ion Separations  

SciTech Connect

The electrically switched ion exchange (ESIX) process, being developed at Pacific Northwest National Laboratory, provides an alternative separation method to selectively remove ions from process and waste streams. In the ESIX process, in which an electroactive ion exchange film is deposited onto a high surface area electrode, uptake and elution are controlled directly by modulating the electrochemical potential of the film. This paper addresses engineering issues necessary to fully develop ESIX for specific industrial alkali cation separation challenges. The cycling and chemical stability and alkali cation selectivity of nickel hexacyanoferrate (NiHCF) electroactive films were investigated. The selectivity of NiHCF was determined using cyclic voltammetry and a quartz crystal microbalance to quantify ion uptake in the film. Separation factors indicated a high selectivity for cesium and a moderate selectivity for potassium in high sodium content solutions. A NiHCF film with improved redox cycling and chemical stability in a simulated pulp mill process stream, a targeted application for ESIX, was also prepared and tested.

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

1999-05-03

268

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

SciTech Connect

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

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

2004-03-29

269

Synthesis and characterization of zirconium(IV) 4-amino, 3-hydroxy naphthalene sulfonate ion exchanger: Quantitative separation of mercury from numerous metal ions  

Microsoft Academic Search

Zirconium (IV) 4-amino, 3-hydroxy naphthalene sulfonate ion-exchanger has been synthesized by mixing equimolar solutions of zirconium oxychloride and ammonium hydroxide in molar ratio 1:1.66 to get a gelatinous material. To this were added varying amounts of 4-amino, 3-hydroxynaphthalene sulphonic acid (ANSA) with constant stiring in order to ensure a complete adsorption of organic molecules to the surface of the gel.

S. Z. Qureshi; G. Asif; M. R. Khayer

1999-01-01

270

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

Microsoft Academic Search

'In this research program, Oak Ridge National Laboratory (ORNL) is collaborating with Texas A and M University in the development of highly selective inorganic ion exchangers for the removal of cesium and strontium from nuclear tank-waste and from groundwater. Inorganic ion exchangers are developed and characterized at Texas A and M University; ORNL is involved in preparing the powders in

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

1997-01-01

271

SOME EXPERIMENTS ON THE USE OF THE CHELATING ION EXCHANGER DOWEX A-1 IN NUCLEAR CHEMISTRY  

Microsoft Academic Search

Two preliminary experiments were performed to study the behavior of ; trivalent ions in the chelating ion exchanger Dowex A-1. The exchange between ; La and Cu in Cu saturated resins showed that the affinity of Dowex A-1 is ; slightly higher for La\\/sup 3+\\/ than for Cu\\/sup 2+\\/ under the conditions employed. ; The separation of La\\/sup 3+\\/ and

R. Christell; S. Forberg; T. Westermark

1961-01-01

272

Surface Hydroxyl Site Densities on Metal Oxides as a Measure for the Ion-Exchange Capacity  

Microsoft Academic Search

Hydroxyl groups on metal oxide in water are the sites for ion exchange, and the surface hydroxyl site density on oxides is a measure of the ion-exchange capacity. Here, the Grignard reagent method was applied to determine the surface hydroxyl site density of oxide samples. The results were similar to those reported for different oxides with other methods (dehydration by

Hiroki Tamura; Akio Tanaka; Ken-ya Mita; Ryusaburo Furuichi

1999-01-01

273

A new class of non-zeolitic sorbents for air separations: Lithium ion exchanged pillared clays  

Microsoft Academic Search

Zeolites are the only known sorbents that adsorb Nâ selectively over Oâ, and are used for industrial air separation. Pillared clays (PILCs) have a high Broensted acidity (k.e., high proton density). It is found in this study that when the protons are exchanged by alkali metal ions, in particular Li{sup +}, the ion exchanged pillared clays can exhibit a high

Linda S. Cheng; Ralph T. Yang

1995-01-01

274

Speciation in metal contaminated soils as revealed by an ion exchange resin membrane fractionation procedure  

Microsoft Academic Search

Ion exchangers have proven to be a useful tool in the study of metal speciation in aquatic environments, but have seen little application in the study of metal behavior in soil environments. The labile metal species in polluted soils were evaluated by equilibrating soil suspensions with ion exchange resin membranes of different types at pH values ranging from 3 to

J. Liang; J. J. Schoenau

1996-01-01

275

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

Microsoft Academic Search

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

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

1998-01-01

276

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

SciTech Connect

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

Not Available

1993-05-01

277

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

SciTech Connect

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

NONE

1995-01-01

278

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

Microsoft Academic Search

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

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

1975-01-01

279

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

SciTech Connect

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

Walker, D.D.

1999-03-15

280

High Performance Liquid Chromatographic Studies of the Ion Exchange Selectivity of Nafion.  

National Technical Information Service (NTIS)

Nafion films were coated on 5 micron octadecyl-derivatized silica. HPLC columns were packed with this film-modified ODS and the ion exchange selectivity of Nafion was studied. A homologous series of organic cations was used to probe the ion exchange prope...

R. B. Moore J. E. Wilkerson C. R. Martin

1984-01-01

281

Use of ion exchange for the treatment of liquids in nuclear power plants  

Microsoft Academic Search

The current and future use of ion exchange (demineralization) as a ; method for treating liquid radioactive streams at nuclear power plants was ; investigated. Pertinent data were obtained by contacting utility companies, ; nuclear-steam-supply system vendors, selected AEC-operated facilities, as well as ; ion exchange resin and equipment manufacturers. Principal emphasis was on ; obtaining data concerning the decontamination

Lin

1973-01-01

282

Ion-exchanged waveguides in glass doped with PbS quantum dots  

Microsoft Academic Search

The lowest-loss (<~1 dB\\/cm) ion-exchanged waveguides in glass doped with PbS quantum dots are presented. Near-field mode profile and refractive index profile using the refracted near-field technique were measured for these waveguides. We demonstrate that the optical properties of this glass remain unchanged during the ion-exchange process.

Jason M. Auxier; Michael M. Morrell; Brian R. West; Seppo Honkanen; Axel Schülzgen; Nasser Peyghambarian; Sabyasachi Sen; Nicholas F. Borrelli

2004-01-01

283

Purification of textile wastewater effluents by a combined Fenton process and ion exchange  

Microsoft Academic Search

Treatment of wastewater effluent from the secondary wastewater treatment plant of a dyeing and finishing mill is investigated for possible reuse. The treatment system employed consists of the Fenton process, chemical coagulation and ion exchange. The Fenton process and chemical coagulation are intended primarily to remove color, turbidity (NTU) and COD concentration of wastewater effluent while ion exchange is used

Sheng H. Lin; Ming L. Chen

1997-01-01

284

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

Microsoft Academic Search

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

Lourdes Dominguez

2002-01-01

285

Weak-Electrolyte Ion Exchange in Advanced-Technology Water-Reuse Systems.  

National Technical Information Service (NTIS)

Ion-exchange treatment can be used to purify wastewater in various ways, including selective removal of individual unwanted ionic species. Weak-acid and weak-base ion exchangers, relatively new on a commercial scale, furnish and exceptional range of perfo...

G. Klein J. Sinkovic T. Vermeulen . H. Williams J. Dong

1982-01-01

286

Nanomaterials-Enhanced Electrically Switched Ion Exchange Process for Water Treatment  

Microsoft Academic Search

The objective of our work is to develop an electrically switched ion exchange (ESIX) system based on conducting polymer\\/carbon nanotube (CNT) nanocomposites as a new and cost-effective approach for removal of radioactive cesium, chromate, and perchlorate from contaminated groundwater. The ESIX technology combines ion exchange and electrochemistry to provide a selective, reversible method for the removal of target species from

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

2009-01-01

287

Cyanide recovery by ion exchange from gold ore waste effluents containing copper  

Microsoft Academic Search

The recovery of cyanide from waste effluents of the cyanidation process in gold extraction plants is important environmentally and economically. In this respect ion exchange is being tested as a possible economic and versatile method for gold ores containing copper minerals. The present study shows the potential of strong and weak base ion exchange resins, particularly the former, for separating

D. Bachiller; M. Torre; M. Rendueles; M. D??az

2004-01-01

288

The effect of domestic ion-exchange water softeners on the microbiological quality of drinking water  

Microsoft Academic Search

This paper covers the testing and evaluation of the impact an ion-exchange water softener has on the microbiological quality of water. Water quality was assessed in two situations, firstly in normal domestic use and secondly under microbial shock loading conditions in the laboratories at Cranfield University. This study was undertaken to determine whether the passage of water through an ion-exchange

Simon A Parsons

2000-01-01

289

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

Microsoft Academic Search

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

Charles A. Lucy

2003-01-01

290

A new concept of nuclear fuel reprocessing by applying ion-exchange technology  

Microsoft Academic Search

The development of advanced technology for the spent nuclear fuel reprocessing should be achieved not only considering cost, non proliferation and reduction of radioactive wastes but also corresponding to both spent nuclear fuels of LWR and FBR.We have proposed an ion exchange process for reprocessing using a new type ion exchanger developed to chemical method of U enrichment technology. This

T. Hoshikawa; F. Kawamura; T. Sawa; A. Suzuoki; M. Kumagai; Y. Takashima; M. Asou; T. Namba; H. Kinumaki; S. Ohe

1998-01-01

291

The Concentration of Trace Elements from Sea Water by Ion Exchange.  

National Technical Information Service (NTIS)

A study was conducted to determine the feasibility of concentrating trace elements found in sea water by ion exchange. The conventional ion-exchange materials are not sufficiently specific in sea water for this task. However, Chelex 100, a chelating resin...

C. M. Callahan J. N. Pascual M. G. Lai

1966-01-01

292

Determination of Cs137 in environmental water by ion-exchange chromatography  

Microsoft Academic Search

Methods of Cs-137 determination employing ion-exchange concentration in environmental waters such as seawater and river water have been reviewed. Ammonium molybdophosphate (AMP) is the most used inorganic ion exchanger for the determination of cesium in water. Since AMP could be obtained only in the form of fine crystals, it was difficult to use it in the columns for separation and

Sushma Gaur

1996-01-01

293

The Award for the Development of Ion Exchange Systems for Food Processing  

NASA Astrophysics Data System (ADS)

In the food industry, ion exchange resins have been used not only for water treatment, but also for the purification of foodstuff itself. Here I will introduce some topics in the development and improvement of ion exchange systems for food proccssing that I have worked on.

Yao, Eiya

294

Ion irradiation effects on the exchange bias in IrMn/Co films  

SciTech Connect

The present work reports on the influence of ion irradiation in exchange-coupled bilayers. Magnetron-sputtered IrMn{sub 4}/Co films were irradiated with 40 keV He{sup +} ions and the dependence of their magnetic properties was studied as function of ion fluence and current used during the irradiations. The effects of ion damage and electronic excitation were also studied through additional irradiations with H{sup +} and Ne{sup +} ions. The results show a clear dependence of the exchange-bias field on the defects caused by the ion bombardment. No correlations with other irradiation effects were observed.

Schafer, D.; Grande, P. L.; Pereira, L. G.; Geshev, J. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, 91501-970 Rio Grande do Sul (Brazil)

2011-01-15

295

Taste masking of Etoricoxib by using ion-exchange resin.  

PubMed

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

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

296

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS. II. HYDROUS ZIRCONIUM OXIDE AND OTHER OXIDES  

Microsoft Academic Search

The oxides ZrOâ, ThOâ, and TiOâ behave as anion ; exchangers in acid and neutral solution and cation exchangers in alkaline ; solution, the pH at which their behavior changes depending upon the oxide itself ; and Possibly also upon the nature of the exchanging ion. The oxides have been ; prepared in granular form and their reversible reactions with

C. B. Amphlett; L. A. McDonald; M. J. Redman

1958-01-01

297

Cleaning condensate in separate ion exchange filters VK-50 turbine plant at nuclear power stations  

Microsoft Academic Search

In order to evaluate the effectiveness of ion exchange resins used in ; cleaning condensates at nuclear power stations by removing dissolved and ; suspended impurities,- and also to check the design of individual units of the ; filters, an experimental plant with separate H-cation exchange and OH-anion ; exchange filters (diameter 2m) in series was installed and tested on

Nudel

1972-01-01

298

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

Microsoft Academic Search

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

A. Dyer; F. H. Kadhim

1989-01-01

299

Nanomaterials-Enhanced Electrically Switched Ion Exchange Process for Water Treatment  

SciTech Connect

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

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

2009-01-01

300

Ion-exchange selectivities of periderm and cuticular membranes toward alkali cations  

SciTech Connect

The ion-exchange selectivities of lithium, sodium, potassium, and cesium on isolated potato periderm (Solanum tuberosum) and pear fruit cuticular membranes were investigated; the general order of preference both for cation selectivities and ion-exchange capacities was lithium > sodium > potassium > cesium. The potato periderm and pear fruit cuticular membranes exhibited a behavior typical of ion-exchange resins of the weak acid type. At constant pH 7, the ion-exchange capacities of periderm and cuticular membranes increased with hydrated ionic radius, and also with increasing pH and neutral salt concentration, and decreased with crystal ionic radius. Counterion selectivities also exhibited the same behavior. The ion-exchange properties are discussed in terms of the structure and function of potato periderm and pear fruit cuticular membranes.

Ersoz, M. [Univ. of Selcuk, Konya (Turkey); Duncan, H.J. [Univ. of Glasgow, Scotland (United Kingdom)

1994-08-01

301

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

SciTech Connect

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

King, W.D.

2001-09-10

302

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

SciTech Connect

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

King, W.D.

2001-02-15

303

Ion Exchange Media for Reduction of Liquid Radwaste in Commercial Power Plants  

SciTech Connect

Ion exchange resins currently make up as much as one-half of all radioactive waste generated by commercial nuclear power plants. A major challenge is reduction of the quantity of ion exchange media requiring disposal. Although the amount of spent ion exchange resins disposed has decreased year after year, a new urgency has arisen with the pending closure of a major disposal site in 2008. This paper explores whether ion exchange resins also can be used to potentially reduce radioactive liquid waste volumes and / or limit them to Class A wastes only. Source term reduction and minimization of manpower exposure to radioactivity are other important goals. Specialty ion exchange products may help to achieve source term reduction of certain radionuclides. Some established operations, data, and process concepts are presented to address these critical issues encountered in liquid radwaste management. (authors)

Yarnell, P.A. [Graver Technologies, LLC, Glasgow, DE (United Kingdom); Tavares, A. [Graver Technologies, LLC, Newark, NJ (United States)

2008-07-01

304

Ratios  

NSDL National Science Digital Library

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

2005-01-01

305

[Method of purification of water by means of ion-exchange cellulose fibers].  

PubMed

A new method of and an arrangement for continuous ion-exchange purification of water from admixtures contained therein in the form of dissolved electrolyte ions have been devised. As a basic working element for this purpose serves anion-exchange tape made of anion-exchange cellulose fibre (ICF) that enables a continuous purification of water from impurities contained therein the be effected as needed. PMID:1233023

Tsibikov, V B; Serafimov, A S; Izbekova, G I; Meerkop, G E

306

Raman Scattering of Hydrogen-Ion-Exchanged LiNbO3 Crystal  

Microsoft Academic Search

Raman spectra of LiNbO3 crystals with different hydrogen-ion-exchanged time were examined. E(TO) and A1(TO) modes appear gradually in the transverse A1- and E-symmetry spectra respectively with increasing the exchange time and the dependence of their intensities on the exchange time is also observed. We attribute these results to both the internal strains resulting from the ordering-disordering distribution of H ions

Xinglong Wu; Mingsheng Zhang; Duan Feng; Zhengtao Liu

1995-01-01

307

Outlook for treatment of nuclear power station process waters with powdered ion-exchange resins  

Microsoft Academic Search

Clarification and ion-exchange treatment of the process water are also combined in the case of ionexchange resin filters of the washed-on type, but some of the disadvantages are lacking here. The extent to which the complete exchange capacity of the ion-exchange resins is utilized in filters of the washed-on type, in both deionization and combined deionization and clarification, is much

O. I. Martynova; N. P. Subbotina; A. S. Kopylov

1969-01-01

308

Comparative studies on electrochemical characterization of homogeneous and heterogeneous type of ion-exchange membranes  

Microsoft Academic Search

Interpolymer films of poly-ethylene and styrene-divinyl benzene copolymer were subjected to chlorosulfonation or chloromethylation then amination for the preparation of homogeneous type of cation- or anion-exchange membranes, respectively. Heterogeneous types of ion-exchange membranes were prepared from polyvinyl chloride (PVC) as binder and ion-exchange resin powder in tetrahydrofuran solvent. Membrane potential and conductance measurements have been carried out in NaCl(aq), CuCl2(aq)

G. S. Gohil; Vinod K. Shahi; R. Rangarajan

2004-01-01

309

Multivariant ion exchange: applications of weak-electrolyte resins in water purification  

Microsoft Academic Search

Weak-electrolyte ion exchange resins differ from strong-electrolyte resins in several aspects, including the dependence of exchange capacity on pH, the tendency to shrink or swell appreciably, and the stronger forces holding the counter-ion in the resin matrix. These differences lead to variations in sorption performance. A model has been developed based on the mass-action law for exchange of a multi-protic

Wheelwright

1982-01-01

310

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

NASA Astrophysics Data System (ADS)

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

Hassanzadeh, Abdollah; Mittler, Silvia

2011-07-01

311

Adsorption of gaseous formaldehyde and carboxylic acids by ammonium-ion-exchanged ?-zirconium phosphate  

Microsoft Academic Search

Ammonium-ion-exchanged ?-Zr(HPO4)2?H2O (?-ZrP) was obtained as a single phase with the interlayer distance of 9.4 Å by the ion-exchange of proton with ammonium ion. The ammonium ion-exchanged ?-ZrP could adsorb ill-smelling gases, such as formaldehyde and carboxylic acids (formic acid, acetic acid, propionic acid, and butyric acid). The adsorption amounts of carboxylic acids increased in the order, butyric acid

A. Hayashi; Y. Fujimoto; Y. Ogawa; H. Nakayama; M. Tsuhako

2005-01-01

312

Photoluminescence of ZnO in metal ion exchanged zeolite Y.  

PubMed

The photoluminescence of nano-sized ZnO in metal-ion-exchanged zeolite Y (ZnO/M-FAU, M = Na, Ca, Er) was investigated. ZnO/M-FAU was prepared by exposing Er(3+)- or Ca(2+)-exchanged Na-FAU to Zn vapor and to air at 723 K. The ZnO formation in the M-FAU showed a change in intensity in the (220), (311) and (331) lines, but no indication of ZnO peaks. In the EDXS and ICPAES analyses, it was found that the molar ratio of Zn/Si was linearly related to the exchanged amount of metal ions, and that the slope of the Zn/Si to the metal/Si was in the order of ZnO/Na-FAU < ZnO/CaNa-FAU < ZnO/ErNa-FAU. In the photoluminescence spectra of all the ZnO/M-FAU samples, peaks were observed at around 380 nm (3.2 eV) and 530 nm (2.5 eV) of ZnO. In ZnO/ErNa-FAU sample, the reabsorption of Er3+ at 520 nm and its emission at 650 nm were observed at the 530 nm peak of ZnO, which can be explained in terms of the interaction of ZnO with Er3+ in the FAU. In the case of ZnO/CaNa-FAU, the peak at around 380 nm was broaden to a longer wavelength, which is supposed to have been caused by emission peak of (CaO)x(ZnO)y. In addition, there were some indications of interaction between Na+ ZnO in ZnO/Na-FAU and the ZnO that was doped with Na+. From the result, it is suggested that ZnO particles were formed in the cavities that interacted with the ions in the zeolites. PMID:21446559

So, Soo Jeong; Kim, Hee Jin; Cha, Du Hwan; Han, Chong Soo

2011-01-01

313

Revised Thermal Analysis of LANL Ion Exchange Column  

SciTech Connect

This document updates a previous calculation of the temperature distributions in a Los Alamos National Laboratory (LANL) ion exchange column.1 LANL operates two laboratory-scale anion exchange columns, in series, to extract Pu-238 from nitric acid solutions. The Defense Nuclear Facilities Safety Board has requested an updated analysis to calculate maximum temperatures for higher resin loading capacities obtained with a new formulation of the Reillex HPQ anion exchange resin. The increased resin loading capacity will not exceed 118 g plutonium per L of resin bed. Calculations were requested for normal operation of the resin bed at the minimum allowable solution feed rate of 30 mL/min and after an interruption of flow at the end of the feed stage, when one of the columns is fully loaded. The object of the analysis is to demonstrate that the decay heat from the Pu-238 will not cause resin bed temperatures to increase to a level where the resin significantly degrades. At low temperatures, resin bed temperatures increase primarily due to decay heat. At {approx}70 C a Low Temperature Exotherm (LTE) resulting from the reaction between 8-12 M HNO{sub 3} and the resin has been observed. The LTE has been attributed to an irreversible oxidation of pendant ethyl benzene groups at the termini of the resin polymer chains by nitric acid. The ethyl benzene groups are converted to benzoic acid moities. The resin can be treated to permanently remove the LTE by heating a resin suspension in 8M HNO{sub 3} for 30-45 minutes. No degradation of the resin performance is observed after the LTE removal treatment. In fact, heating the resin in boiling ({approx}115-120 C) 12 M HNO{sub 3} for 3 hr displays thermal stability analogous to resin that has been treated to remove the LTE. The analysis is based on a previous study of the SRS Frames Waste Recovery (FWR) column, performed in support of the Pu-238 production campaign for NASA's Cassini mission. In that study, temperature transients following an interruption of flow to the column were calculated. The transient calculations were terminated after the maximum resin bed temperature reached the Technical Standard of 60 C, which was set to prevent significant resin degradation. The LANL column differs from the FWR column in that it has a significantly smaller radius, 3.73 cm nominal versus approximately 28 cm. It follows that natural convection removes heat much more effectively from the LANL column, so that the column may reach thermal equilibrium. Consequently, the calculations for a flow interruption were extended until an approach to thermal equilibrium was observed. The LANL ion exchange process also uses a different resin than was used in the FWR column. The LANL column uses Reillex HPQ{trademark} resin, which is more resistant to attack by nitric acid than the Ionac 641{trademark} resin used in the FWR column. Heat generation from the resin oxidation reaction with nitric acid is neglected in this analysis since LANL will be treating the resin to remove the LTE prior to loading the resin in the columns. Calculations were performed using a finite difference computer code, which incorporates models for absorption and elution of plutonium and for forced and natural convection within the resin bed. Calculations for normal column operation during loading were performed using an initial temperature and a feed temperature equal to the ambient air temperature. The model for the normal flow calculations did not include natural convection within the resin bed. The no flow calculations were started with the temperature and concentration profiles at the end of the loading stage, when there would be a maximum amount of plutonium either adsorbed on the resin or in the feed solution in the column.

Laurinat, J

2006-04-11

314

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

PubMed

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

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

2010-06-01

315

Ion exchange of alkali metals on hydrous titanium dioxide in neutral and alkaline solutions  

Microsoft Academic Search

Selectivity of hydrous titanium dioxide as an ion exchanger for alkali metal and tetraalkylammonium ions, has been studied using radioactive indicators:22Na and137Cs. The equilibrium distribution of trace amounts of sodium and cesium ions between the exchanger and aqueous solutions containing macroamounts of other univalent cations was studied over the temperature range of 15 to 80°C. The selectivity sequence in slightly

A. Bilewicz; R. Dybczynski; J. Narbutt

1991-01-01

316

Extended ion exchange process for removal and recovery of technetium from soluble waste  

Microsoft Academic Search

A well-established method of separation of ⁹⁹Tc from soluble waste is sorption of pertechnetate ion, TcOâ⁻, onto a strong base anion exchange resin such as Dowex 1x8. Pertechnetate ion can then be removed from the resin by elution with 4M HNOâ. An improved ion exchange method which encompasses removal and recovery of ⁹⁹Tc from defense waste supernate has been demonstrated.

J. P. Bibler; R. M. Wallace

1984-01-01

317

Ion-exchange properties of a salicylic acid–melamine–formaldehyde terpolymer resin  

Microsoft Academic Search

Terpolymer resins, synthesized by the condensation of salicylic acid and melamine with formaldehyde in the presence of an acid catalyst, proved to be a selective chelating ion-exchange polymer for certain metals. The chelating ion-exchange properties of this polymer were studied for Cu2+, Ni2+, Co2+, Zn2+, Fe3+, Cd2+ and Pb2+ ions. A batch equilibrium method was employed in the study of

Wasudeo B Gurnule; H. D Juneja; L. J Paliwal

2002-01-01

318

Evaluation of Ion Exchange Technology for Toxic and Non-Conventional Pollutant Reduction in Bleach Plant Effluents.  

National Technical Information Service (NTIS)

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

J. H. Fitch

1981-01-01

319

High Ion/Ioff ratio of electrochemically prepared graphene quantum dots  

NASA Astrophysics Data System (ADS)

Herein we report lithographically fabricated FET with annealed graphene quantum dots (GQDs) as channel shows higher Ion/Ioff ratio as compared to as-prepared GQDs as channel. GQDs are synthesized via an electrochemical avenue using multiwall carbon nanotubes. As-prepared dots of 4.5 +/- 0.55 nm average diameter are found to be p-type in air under ambient conditions with Ion/Ioff ratio of 45 and after annealing in Argon atmosphere at 300°C for 20 min it shows ambipolar nature with significant increase in resistance with Ion/Ioff ratio of 200.

Kalita, Hemen; Harikrishnan, V.; Aslam, M.

2013-06-01

320

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

SciTech Connect

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

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

2010-10-15

321

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

322

Medium Effects on Charged Pion Ratio in Heavy Ion Collisions  

Microsoft Academic Search

We have recently studied in the delta-resonance-nucleon-hole model the dependence of the pion spectral function in hot dense asymmetric nuclear matter on the charge of the pion due to the pion p-wave interaction in nuclear medium. In a thermal model, this isospin-dependent effect enhances the ratio of negatively charged to positively charged pions in neutron-rich nuclear matter, and the effect

Che Ming Ko; Yongseok Oh; Jun Xu

2010-01-01

323

Removal of fluoride from spent pot liner leachate using ion exchange  

SciTech Connect

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

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

1999-01-01

324

Application of ion exchange resin in floating drug delivery system.  

PubMed

The purpose of this study was to explore the application of low-density ion exchange resin (IER) Tulsion(R) 344, for floating drug delivery system (FDDS), and study the effect of its particle size on rate of complexation, water uptake, drug release, and in situ complex formation. Batch method was used for the preparation of complexes, which were characterized by physical methods. Tablet containing resin with high degree of crosslinking showed buoyancy lag time (BLT) of 5-8 min. Decreasing the particle size of resin showed decrease in water uptake and drug release, with no significant effect on the rate of complexation and in situ complex formation for both preformed complexes (PCs) and physical mixtures (PMs). Thus, low-density and high degree of crosslinking of resin and water uptake may be the governing factor for controlling the initial release of tablet containing PMs but not in situ complex formation. However, further sustained release may be due to in situ complex formation. PMID:18777244

Upadhye, Abhijeet A; Ambike, Anshuman A; Mahadik, Kakasaheb R; Paradkar, Anant

2008-10-01

325

Crystalline Silicotitanate Ion Exchange Support for Salt-Alternatives  

SciTech Connect

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

Fondeur, F.F.

2001-02-23

326

Ion Exchange Resin and Clay Vitrification by Plasma Discharges  

NASA Astrophysics Data System (ADS)

The lack of treatment of a low and intermediate level radioactive waste (LILRW) lead us to propose a vitrification process based on a plasma discharge; this technique incorporates LILRW into a matrix glass composed of ceramic clays material. The Mexican Institute of Nuclear Research (ININ), uses an ion exchange resin IRN 150 (styrene-divinilbence copolymer) in the TRIGA MARK III nuclear reactor. The principal objective of this resin is to absorb particles containing heavy metals and low-level radioactive particles. Once the IRN 150 resin filter capacity has been exceeded, it should be replaced and treated as LILRW. In this work, a transferred plasma system was realized to vitrify this resin taking advantage of its high power density, enthalpy and chemical reactivity as well as its rapid quenching and high operation temperatures. In order to characterize the morphological structure of these clay samples, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Thermogravimetric analysis (TGA) techniques were applied before and after the plasma treatment.

Díaz A., Laura V.; Pacheco S., Joel O.; Pacheco P., Marquidia; Monroy G., Fabiola; Emeterio H., Miguel; Ramos F., Fidel

2006-12-01

327

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

Microsoft Academic Search

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

Mark N. Kobrak

2008-01-01

328

Kinetics of sorption of niobium ions by anion-exchangers from mixed chloride-fluoride solutions  

SciTech Connect

The authors showed earlier on the basis of experimental and calculated data obtained in studies of ion-exchange equilibrium that the sorbability and composition of sorbed niobium ions are determined by the content of hydrofluoric acid in mixed chloride-fluoride solutions. Variation of the ionic state of niobium in these solutions should also influence the rate of ion exchange. In this communication they examine the results of a study of the kinetics of exchange of niobium ions on AV-17 x 8, EDE-10P, and AN-2F anion-exchange resins in fluoride-containing solutions. Kinetic curves for sorption of niobium ions and the results of their evaluation are presented.

Rychkov, V.N.; Pakholkov, V.S.; Kuznetsova, L.D.

1987-08-10

329

Interionic and intermolecular interactions in ion-exchange and sorption systems involving physiologically active substances  

SciTech Connect

This paper reviews the results obtained by studying the sorption of physiologically active substances (PAS) of different types such as, amino acids, nucleotides and melanoidins on ion exchangers and non-ionogenic sorbents. The review is mainly focused upon the mechanisms of interaction of PAS molecules in the sorbent phase. The contribution of ion-ionic, ion-molecular and intermolecular interactions to the overall sorption effect is discussed. The results of studying ion-exchange isothermal supersaturation of amino acid solutions on anion exchangers are reported and discussed. The mechanisms of aging of ion-exchange materials in the course of recovery of PAS from fermentation broths and hydrolysates are proposed. 48 refs.

Selemenev, V.F.; Chikin, G.A.; Khokhlov, V.J.

1999-07-01

330

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

SciTech Connect

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

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

1988-06-20

331

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

SciTech Connect

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

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

2010-01-01

332

Ratios  

NSDL National Science Digital Library

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

Stapel, Elizabeth

2000-01-01

333

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

SciTech Connect

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

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

1992-06-01

334

Separation of Molybdenum-Uranium by a Process Combining Ion Exchange Resin and Membranes  

NASA Astrophysics Data System (ADS)

The purpose of this study is to determine whether the electrodeionization with ion-exchange resin is suitable for removing uranium from a solution containing molybdenum. A hybrid process combining ion exchange (resins and membranes) using electric current. For this electroextraction process, the cation exchange resin is introduced into an electrodialysis cell and compressed between two cations exchange membranes. We have investigated a continuous electroextraction process. As important result we note that: The factor of selectivity,r, for molybdenum versus uranium is superior to 3; the concentration in radio active element (U3O8) is lower than 1.5 mg L-1 and small cell voltage is observed.

Lounis, A.; Setti, L.; Djennane, A.; Melikchi, R.

335

Theory of dipole-exchange spin waves in metallic ferromagnetic nanotubes of large aspect ratio  

NASA Astrophysics Data System (ADS)

A macroscopic continuum theory is presented for the dipole-exchange spin waves in nanometer-sized cylindrical tubes with a large length-to-diameter aspect ratio. The magnetization and applied magnetic field are taken parallel to the cylinder axis, and the properties of the hybridized surface and bulk magnetic excitations are studied in relation to the inner and outer interfaces of the nanotubes. The calculations describe the radial and angular quantization of the different modes for both unpinned and effective pinned cases. The results for tube geometries are found to be in contrast with the limiting (single-interface) special cases of wires and antiwires. Numerical examples are presented mainly for Ni materials.

Das, Tushar K.; Cottam, Michael G.

2011-04-01

336

Thermal FT-IR microspectroscopy for rapid detection of solid-state ion-exchange reaction between metoclopramide HCl monohydrate and potassium bromide.  

PubMed

The combination of Fourier transform infrared (FT-IR) microspectroscopy with a thermal analyzer was applied to quickly investigate the solid-state ion-exchange reaction of metoclopramide HCl monohydrate (MCP H(2)O) by clipping MCP H(2)O powder between two KBr or KCl pellets. The physical and ground mixtures of MCP H(2)O or 150 °C-preheated MCP powder and KBr or KCl powders with a weight ratio of 1 : 100 were also prepared and determined by FT-IR microspectroscopy. The samples of MCP H(2)O or 150 °C-preheated MCP were identified by using differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The results of present study indicate that the ion-exchange reaction was easily induced between MCP H(2)O and KBr by grinding and heating processes. The possible mechanism of ion-exchange reaction may take place between the HCl salt of MCP H(2)O and a KBr matrix by grinding or heating to yield a mixture of HCl and HBr salts of the MCP sample in the presence of hydrated water. The crystal hydrate played an important role to improve this ion-exchange reaction between MCP H(2)O and KBr. However, no ion-exchange reaction occurred between MCP H(2)O and KCl or between 150 °C-preheated MCP and KBr. The solid-state ion-exchange reaction was more easily determined by this novel thermal FT-IR microspectroscopy than other conventional methods. PMID:21183974

Cheng, Wen-Ting; Wang, Shun-Li; Lin, Shan-Yang

2010-12-23

337

Kinetics Characterization of Ions Release Under Dynamic and Batch Conditions. Strong Acid and Strong Base Type Ion Exchange Resins  

Microsoft Academic Search

The purpose of this study has been to investigate the influence of key parameters (i.e., the structure of the resin organic polymer and its particle size, as well as the temperature of the process) on the release of calcium and fluoride ions from cationic and anionic ion exchange resins of strong character, in order to develop a formulation for a

A. Torrado; M. Valiente

2008-01-01

338

Uranium ion exchange from low-grade acidic solutions in a fluidized system  

SciTech Connect

Using a fluidized, countercurrent multiple-compartment ion-exchange (MCIX) column previously developed by the Bureau of Mines, Bureau researchers have successfully extracted uranium from a simulated acidic in situ leach liquor that contained 150 ppM U/sub 3/O/sub 8/. This successful demonstration of the MCIX system is reported, and the effects of varying the operating conditions on the performance of the system are also examined. Operating the MCIX system with a flow rate of 15 gpm/ft/sup 2/ and an aqueous-to-resin flow ratio of 200:1, more than 90% of the uranium was extracted, and a resin containing approximately 28 grams U/sub 3/O/sub 8/ per liter was produced. The absorption column used to investigate the operating variables was approximately 18 feet long with a 2-inch ID and was divided into compartments that were 1 foot long.

Palmer, G.R.; Nichols, I.L.; Seidel, D.C.

1980-01-01

339

Anomalous exchange bias behavior in ion-beam bombarded NiCo/(Ni,Co)O bilayers  

SciTech Connect

The structural and magnetic properties of NiCo/(Ni,Co)O bilayers were investigated. X-ray diffractometry results have shown that the top NiCo layer consisted of a fcc NiCo phase. The bilayer bottom was either a pure (Ni,Co)O or a composite [NiCo+(Ni,Co)O] phase, depending on the percent of O{sub 2}/Ar ratio used during deposition. A double-shifted hysteresis loop exhibiting components that were from positive or negative coupling was observed in the NiCo/(Ni,Co)O (8%O{sub 2}/Ar) bilayers. The microstructural changes, which result from a combination of deposition oxygen content and the ion-beam bombardment, will result in the unusual exchange bias behavior.

Lin, K.-W.; Guo, J.-Y.; Liu, H.-Y.; Ouyang, H. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Chan, Y.-L.; Wei, D.-H. [National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Lierop, J. van [Department of Physics and Astronomy, University of Manitoba, Winnipeg R3T2N2 (Canada)

2008-04-01

340

Performance of an electron cyclotron resonance ion source designed for isotope ratio mass spectrometry  

SciTech Connect

We have designed, built, and tested an electron cyclotron resonance ion source suited to the needs of an experimental program examining new methods of isotope ratio mass spectrometry using multiply charged ions. Contaminant levels have been reduced to low levels. Sample absorption and desorption effects are under investigation and preliminary results are presented.

Hotchkis, M. A. C.; Buckley, D.; Button, D. [Australian Nuclear Science and Technology Organisation, PMB 1, Menai, New South Wales 2234 (Australia)

2008-02-15

341

Performance of an electron cyclotron resonance ion source designed for isotope ratio mass spectrometry  

Microsoft Academic Search

We have designed, built, and tested an electron cyclotron resonance ion source suited to the needs of an experimental program examining new methods of isotope ratio mass spectrometry using multiply charged ions. Contaminant levels have been reduced to low levels. Sample absorption and desorption effects are under investigation and preliminary results are presented.

M. A. C. Hotchkis; D. Buckley; D. Button

2008-01-01

342

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

SciTech Connect

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

Beigman, I L; Vishnyakov, E A; Luginin, M S; Ragozin, Evgenii N; Tolstikhina, I Yu [P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2010-08-27

343

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

SciTech Connect

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

Spires, Renee; Punch, Timothy; McCabe, Daniel

2009-02-11

344

Vitrification of ion exchange materials. Innovative technology summary report  

SciTech Connect

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

Not Available

1999-07-01

345

Synthesis and sulfate ion-exchange properties of a hydrotalcite-like compound intercalated by chloride ions.  

PubMed

To reduce the generation of hydrogen sulfide gas from sulfate ions, we synthesized a layered double hydroxide hydrotalcite-like compound intercalated with chloride ions in the interlayer (HT-Cl) using a coprecipitation reaction. The resultant HT-Cl material had a Mg/Al molar ratio of approximately 2, and the molar fraction of the chloride ions on the intercalated anion layer of the HT was 0.90. A higher molar fraction of chloride ions can be inserted into the interlayers of the HT by increasing the initial concentration ratio of chloride ions to aluminum ions [Cl(-)](0)/[Al(3+)](0) in the solution. Approximately 98% of the sulfate ions in the solution were removed within 10 min after adding 1.12 times the stoichiometric quantity of synthesized HT-Cl, which contained a Mg/Al molar ratio of 2 equal to a solution containing a 12 mM calcium sulfate solution. PMID:17079079

Tsujimura, Akino; Uchida, Miho; Okuwaki, Akitsugu

2006-09-29

346

Effect of ion-exchange purification on the determination of plutonium at the New Brunswick Laboratory.  

National Technical Information Service (NTIS)

The method of plutonium (Pu) determination at the Brunswick Laboratory (NBL) consists of a combination of ion-exchange purification followed by controlled-potential coulometric analysis (IE/CPC). The present report's purpose is to quantify any detectable ...

W. G. Mitchell M. I. Spaletto K. Lewis M. D. Soriano M. W. Smith

1990-01-01

347

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

ERIC Educational Resources Information Center

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

Dietz, Mark L.

1986-01-01

348

Ion Exchange Separation and Mass Spectrometric Analysis of Uranium for Solutions Containing Plutonium.  

National Technical Information Service (NTIS)

An ion exchange technique separates plutonium from uranium using Dowex-1 resin and a methanol--HCl plutonium elutriant. The method is applicable to both trace uranium determination and uranium isotopic distribution analysis by mass spectrometry. Distribut...

K. C. McBride

1975-01-01

349

Fractionation of Complex Combustion Mixtures Using an Ion-Exchange Methodology.  

National Technical Information Service (NTIS)

Fractionation of particle emission extracts captured from complex combustion mixtures was performed upon environmental samples using an ion-exchange technique. Captured emissions from hazardous waste, municipal and medical/pathological incinerators along ...

R. Williams L. Brooks M. Taylor D. Thompson D. Bell

1991-01-01

350

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

National Technical Information Service (NTIS)

Management of spent ion-exchange resin waste arising from nuclear reactor operations by traditional practice of encapsulation in cement is associated with problems such as swelling and disintegration. Complete oxidation (mineralization) is an attractive a...

C. Srinivas G. Sugilal P. K. Wattal

2003-01-01

351

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

SciTech Connect

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

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

1996-04-01

352

Spatial distributions of scandium in granules of different ion-exchangers  

SciTech Connect

Scanning electron microscopy (SEM) and electron probe microanalysis (EPM) using an electron probe with high local sensitivity in nondestructive action on the sample, which is important in the analysis of ion-exchange materials, are efficient methods for physicochemical studies. SEM and EPM make it possible to study the spatial distribution of elements, characteristics of their absorption by ion-exchange materials, and establish the mechanisms of physicochemical transformations, the composition of microsections of granules, etc.. Effective ion-exchangers for extraction of scandium from sulfuric acid solutions were selected, and the characteristics of sorption absorption of scandium and the accompanying elements on these ion-exchangers were investigated by SEM and EPM. 11 refs., 2 figs.

Komarova, N.I.; Molchanova, T.V.; Rodionov, V.V.; Vodolazov, L.I.

1992-01-20

353

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

SciTech Connect

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

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

2008-08-26

354

Calculation of Isotopic Profile During Band Displacement on Ion-Exchange Resins.  

National Technical Information Service (NTIS)

A method has been developed to calculate the isotopic profile during band displacement on ion exchange resins using computer simulation. Persoz had utilized this technique earlier for calculating the isotopic profile during band displacement as well as fr...

A. S. Sonwalkar V. D. Puranik A. B. D'Souza

1981-01-01

355

Continuous Stationary-Bed Ion Exchange: Incomparable Power for Difficult Separations Involving Higher Value Products.  

National Technical Information Service (NTIS)

Chromatography, ion exchange, and other techniques based on the interaction of solutes with solid phases offer versatility, high resolution capabilities, and near-universal potential applicability for the separation of valuable constituents in liquid solu...

R. M. Canon J. M. Begovich

1985-01-01

356

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2013 CFR

...dimethylamine and oxidized with hydrogen peroxide whereby the resin contains not...calcium, carbonate, chloride, hydrogen, hydroxyl, magnesium...cation-exchange resins in the hydrogen form identified in...

2013-04-01

357

Effect of Cerium on the Ion-Exchange Parameters in Alkali Silicate Glasses  

Microsoft Academic Search

Alkali gallosilicate glasses containing 1–8 mol % CeO2 after ion-exchange treatment in a NaNO3 melt at different temperatures are studied. The refractive index distributions in glasses with different cerium oxide contents are obtained, and the profiles of the Na2O concentration distribution in the samples containing 2 mol % CeO2 after ion-exchange treatment at temperatures T = 500–550°C are determined. It

T. V. Bocharova; Yu. A. Zhatkin; G. O. Karapetyan

2005-01-01

358

Hydrophilic Interaction Liquid Chromatographic (HILIC)\\/Ion Exchange Separation of Picolinic and Nicotinic Acids  

Microsoft Academic Search

A hydrophilic interaction liquid chromatography (HILIC)\\/ion?exchange method for the analysis of nicotinic and picolinic acid is presented. Separation of nicotinic and picolinic acid was achieved at relatively high acetonitrile concentration (70%). Various aspects of the separation were examined, including buffer concentration, column temperature, buffer pH, and column configuration. Throughout the study, the method demonstrated characteristics of both ion?exchange and HILIC

Matthew J. Christopherson; Kenton J. Yoder; Jason T. Hill

2006-01-01

359

Ion exchange and electrochemical evaluation of the microporous phosphate LiFe(PO)  

Microsoft Academic Search

A new lithium iron(III) phosphate, LiFe(PO), has been synthesized and is currently under electrochemical evaluation as an anode material for rechargeable lithium-ion battery applications. The sample was prepared via the ion exchange reaction of CsKFe(PO)1 in the 1 M LiNO solution under hydrothermal conditions at 200 deg. C. The fully Li{sup +}-exchanged sample LiFe(PO)2 cannot yet be synthesized by conventional

Gregory A. Becht; John T. Vaughey; Robin L. Britt; Cassandra T. Eagle; Shiou-Jyh Hwu

2008-01-01

360

Conditioning the slag formed during thermochemical treatment of spent ion-exchange resins  

Microsoft Academic Search

This article describes the composition of an optimized powdered metallized fuel for thermochemical treatment of spent ion-exchange\\u000a resins for the production of slags that are suitable for inclusion in lowtemperature magnesium phosphate ceramic. Mineral\\u000a additives are added to this fuel which bind sulfo-groups in the ion-exchange resins into compounds with low solubility in\\u000a water. Test samples of magnesium phosphate ceramic

M. S. Bortnikova; O. K. Karlina; G. Yu. Pavlova; K. N. Semenov; S. A. Dmitriev

2008-01-01

361

Management of Spent Organic Ion-Exchange Resins by Photochemical Oxidation  

Microsoft Academic Search

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

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

2003-01-01

362

Molten Salt Oxidation of Ion-exchange Resins Doped with Toxic Metals and Radioactive Metal Surrogates  

Microsoft Academic Search

Ion-exchange resins doped with toxic metals and radioactive metal surrogates were test-burned in a bench-scale molten salt oxidation (MSO) reactor system. The purposes of this study are to confirm the destruction performance of the two-stage MSO reactor system for the organic ion-exchange resin and to obtain an understanding of the behavior of the fixed toxic metals and the sulfur in

Hee-Chul YANG; Yong-Jun CHO; Hee-Chul EUN; Jae-Hyung YOO; Joon-Hyung KIM

2005-01-01

363

Standardization of catalyst preparation using reference catalyst: ion exchange of mordenite type zeolite  

Microsoft Academic Search

A joint study was organized to establish a standard set of conditions for the ion exchange of zeolite from sodium into proton-form. The sodium-form mordenite with Si\\/Al2=ca. 15 was ion exchanged into an NH4-form, followed by calcination according to various recipes. Then various advanced techniques for characterization (ICP, TG, XPS, SEM, XRD, N2 adsorption, 29Si and 27Al NMR, benzene diffusion,

Naonobu Katada; Tatsuya Takeguchi; Tatsuya Suzuki; Toshihisa Fukushima; Kinya Inagaki; Setsuo Tokunaga; Hiromichi Shimada; Koichi Sato; Yasunori Oumi; Tsuneji Sano; Kohichi Segawa; Kazuyuki Nakai; Hiroshi Shoji; Peng Wu; Takashi Tatsumi; Takayuki Komatsu; Takao Masuda; Kazunari Domen; Eisuke Yoda; Junko N. Kondo; Toshio Okuhara; Yasuyoshi Kageyama; Miki Niwa; Masaru Ogura; Masahiko Matsukata; Eiichi Kikuchi; Noriyasu Okazaki; Motoi Takahashi; Akio Tada; Shogo Tawada; Yoshihiro Kubota; Yoshihiro Sugi; Yasuhiko Higashio; Masahiko Kamada; Yukiyo Kioka; Kohei Yamamoto; Takayuki Shouji; Yusaku Arima; Yasuaki Okamoto; Hideyuki Matsumoto

2005-01-01

364

Pilot scale recovery of monoclonal antibodies by expanded bed ion exchange adsorption  

Microsoft Academic Search

The aim of the investigations was to estimate the scale up properties of an efficient chromatographic first capture step for the recovery of murine IgG1 from undiluted and unclarified hybridoma cell culture broth using an ion exchange matrix in expanded bed mode. The tested new sulfopropyl-based ion exchange matrix (StreamlineTM SP XL, Amersham Pharmacia Biotech) stands out due to its

Nicole Ameskamp; Christoph Priesner; Jürgen Lehmann; Dirk Lütkemeyer

1999-01-01

365

Ion-exchange fibers and drugs: a novel device for the screening of iontophoretic systems  

Microsoft Academic Search

The objective of this study was to theoretically model and experimentally measure the extent of drug release from ion-exchange fibers. The release was measured as a function of current density and NaCl concentration using a novel iontophoretic cell. The fibers tested contained weak carboxylate (–COOH) ion-exchange groups. The cationic model drugs tacrine and metoprolol were chosen on the basis of

M. Vuorio; L. Murtomaki; J Hirvonen; K Kontturi

2004-01-01

366

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

SciTech Connect

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

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

2009-03-17

367

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

SciTech Connect

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

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

1996-04-01

368

The effect of ion exchange on the solubility of fluoride compounds  

Microsoft Academic Search

The influence of ion exchange processes on the apparent solubility of fluoride compounds was examined by observing changes in free F- and total F levels when suspensions of sparingly soluble fluoride species (e.g., CaF2, AlF3) and aluminium smelter wastes were equilibrated with a range of materials having different cation exchange capacities. The exchanger materials used included synthetic resins, clay minerals,

W. F. Pickering; J. Slavek; P. Waller

1988-01-01

369

Diffusion behavior of transition metals in field-assisted ion-exchanged glasses  

Microsoft Academic Search

The use of ion-exchange techniques for doping silicate glasses with transition metals has attracted much attention in the last decades for its potential in several applications, namely, light waveguides technology, luminescent materials, and for the possibility to realize systems in which metal nanocluster formation is controlled by suitable post-exchange techniques. In this framework, the control of metal distribution inside the

F. Gonella; E. Cattaruzza; A. Quaranta; S. Ali; N. Argiolas; C. Sada

2006-01-01

370

CHANGES IN THE PROPERTIES OF ION-EXCHANGE RESINS PRODUCED BY IRRADIATION WITH IONIZING RADIATION  

Microsoft Academic Search

Changes in the exchange capacity, activity index, swelling in water, and ; in the solubllity of ion exchange resins (IER) produced by exposure to x rays ; were investigated. The changes produced when dry and waterswollen IER are ; irradiated with x rays are quite different. Direct irradiation effects were ; established as well as an indirect hydroxylation effect which

O. Costachel; Gh. Furnica; St. Grigorescu

1958-01-01

371

Modeling a novel ion exchange process for arsenic and nitrate removal  

Microsoft Academic Search

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

Jaeshin Kim; Mark M Benjamin

2004-01-01

372

Mg\\/NH4 Ion Exchange Kinetics under Isothermal Supersaturated Conditions  

Microsoft Academic Search

Ion Exchange Isothermal Supersaturation process (IXISS) allows the recovery of the salt from the elution solution without any additional reagent or step. This work focuses on the batch elution kinetics of magnesium with ammonium from two commercial resins under supersaturated conditions – i.e., conditions far above from the solubility of magnesium. The Mg\\/NH4 exchange was measured by chemical analysis and

M. Ortueta; A. Celaya; F. Mijangos; D. Muraviev

2008-01-01

373

Bilinear-biquadratic quantum exchange model with single-ion uniaxial anisotropy  

NASA Astrophysics Data System (ADS)

Anisotropic XXZ Heisenberg ferromagnets with biquadratic exchange and single-ion anisotropy are studied by an improved two-site cluster effective field theory. In particular, the cross-over from anisotropic Ising to isotropic Heisenberg behaviour in the variation of Tc with biquadratic exchange strength is studied and compared with the results of other methods.

Idogaki, T.; Tanaka, A.; Tucker, J. W.

1998-01-01

374

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

Microsoft Academic Search

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

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

2009-01-01

375

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

EPA Science Inventory

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

376

Superhydrophobic silica aerogel powders with simultaneous surface modification, solvent exchange and sodium ion removal from hydrogels  

Microsoft Academic Search

We report a novel method for the rapid synthesis of superhydrophobic silica aerogel powders based on an inexpensive precursor such as sodium silicate via ambient pressure drying. The sodium silicate was directly polymerized without prior ion exchange by the addition of nitric acid and hexamethyldisilazane (HMDS) to yield silylated hydrogels. The indispensable steps such as surface modification, solvent exchange and

Sharad D. Bhagat; Yong-Ha Kim; Kuen-Hack Suh; Young-Soo Ahn; Jeong-Gu Yeo; Jong-Hun Han

2008-01-01

377

Selective Recovery of Platinum Group Metals From Spent Automobile Catalyst by Integrated Ion Exchange Methods  

Microsoft Academic Search

Selective Recovery of platinum group metals (PGMs), such as Pd, Pt and Rh, from spent automobile catalyst has been investigated by integrated ion exchange method using dihexyl sulfide (DHS) impregnated resin and commercial weak anion exchange resin (Diaion WA-21) as adsorbents. Batchwise adsorption revealed DHS impregnated resin possesses the selective adsorption ability for Pd and WA-21 possesses selectivity for all

Shuhei Tanaka; Akinori Harada; Syouhei Nishihama; Kazuharu Yoshizuka

2012-01-01

378

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

Microsoft Academic Search

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

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

2008-01-01

379

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

NASA Astrophysics Data System (ADS)

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

Kumar, S. T. A.; Almagri, A. F.; Craig, D.; Den Hartog, D. J.; Nornberg, M. D.; Sarff, J. S.; Terry, P. W.

2013-05-01

380

Preparation and characterization of ABS\\/HIPS heterogeneous cation exchange membranes with various blend ratios of polymer binder  

Microsoft Academic Search

In this research, acrylonitrile–butadiene–styrene (ABS)\\/high impact polystyrene (HIPS) blend heterogeneous cation exchange membranes were prepared by solution casting technique using tetrahydrofuran as solvent and cation exchange resin powder as functional group agent. The effect of blend ratio of polymers binder (ABS to HIPS) on properties of the prepared membranes was studied. Ultrasonic was used to appropriately disperse particles in the

S. M. Hosseini; S. S. Madaeni; A. R. Khodabakhshi

2010-01-01

381

Desalination and hydrogen, chlorine, and sodium hydroxide production via electrophoretic ion exchange and precipitation.  

PubMed

We demonstrate and analyze a novel desalination method which works by electrophoretically replacing sodium and chloride in feed salt water with a pair of ions, calcium and carbonate, that react and precipitate out. The resulting calcium carbonate precipitate is benign to health, and can be filtered or settled out, yielding low ionic strength product water. The ion exchange and precipitation employs self-sharpening interfaces induced by movement of multiple ions in an electric field to prevent contamination of the product water. Simultaneously, the electrolysis associated with the electromigration produces hydrogen gas, chlorine gas, and sodium hydroxide. We conducted an experimental study of this method's basic efficacy to desalinate salt water from 100 to 600 mol m(-3) sodium chloride. We also present physicochemical models of the process, and analyze replacement reagents consumption, permeate recovery ratio, and energy consumption. We hypothesize that the precipitate can be recycled back to replacement reagents using the well-known, commercially implemented Solvay process. We show that the method's permeate recovery ratio is 58% to 46%, which is on par with that of reverse osmosis. We show that the method's energy consumption requirement over and above that necessary to generate electrolysis is 3 to 10 W h l(-1), which is on par with the energy consumed by state-of-the-art desalination methods. Furthermore, the method operates at ambient temperature and pressure, and uses no specialized membranes. The process may be feasible as a part of a desalination-co-generation facility: generating fresh water, hydrogen and chlorine gas, and sodium hydroxide. PMID:22806549

Shkolnikov, Viktor; Bahga, Supreet S; Santiago, Juan G

2012-07-17

382

Identification of selective ion-exchange resin for fluoride sorption  

Microsoft Academic Search

The defluoridation capacity (DC) of a chelating resin, namely Indion FR 10 (IND), and Ceralite IRA 400 (CER), an anion-exchange resin, were compared under various equilibrating conditions for the identification of selective sorbent. The results showed that chelating resin is more selective than an anion-exchange resin for fluoride removal. The fluoride sorption was reasonably explained using Freundlich and Langmuir isotherms.

S. Meenakshi; Natrayasamy Viswanathan

2007-01-01

383

Ion-exchange material and method of storing radioactive wastes  

DOEpatents

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

Komarneni, S.; Roy, D.M.

1983-10-31

384

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

SciTech Connect

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

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

2008-06-15

385

CHARACTERIZATION OF CYCLED SPHERICAL RESORCINOL-FORMALDEHYDE ION EXCHANGE RESIN  

SciTech Connect

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

Nash, C.; Duignan, M.

2010-02-23

386

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

SciTech Connect

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

Lukens, Wayne W.; Walter, Marc D.

2010-04-01

387

Charge-Exchange Experiments with Highly Charged Ions and Their Relevance to Astrophysics  

NASA Astrophysics Data System (ADS)

The wide range of highly-charged ions (HCIs) and charge states produced in the electron cyclotron resonance ion source allows one to study fundamental atomic-physics processes both for their intrinsic value, and for their importance to understanding astrophysical phenomena. These phenomena include ionization fractions of solar/stellar plasmas; charge exchange with comets, circumstellar clouds, and planetary & satellite exospheres. Presented will be recent experimental and theoretical results for absolute single and multiple charge-exchange cross sections for HCI-neutral collisions, together with spectra of X-ray emissions following the charge-exchange collision. In collaboration with Stojan Madzunkov, John MacAskill, Ara Chutjian, Jet Propulsion Lab.

Simcic, Jurij

2011-06-01

388

An Ion-Exchange Process for Recovery of Chromate From Pigment Manufacturing.  

National Technical Information Service (NTIS)

Strongly basic ion-exchange resins have been shown to exhibit a preference for dichromate over many other anions in water solution. Laboratory studies were conducted to show that this ion preference could be used to remove chromate from waste waters which...

D. J. Robinson H. E. Weisberg G. I. Chase K. R. Libby J. L. Capper

1974-01-01

389

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

Microsoft Academic Search

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

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

2005-01-01

390

Structural changes of soda-lime silica glass induced by a two-step ion exchange  

Microsoft Academic Search

Introduction of silver or copper ions in soda-lime silica glass has been investigated by studying the data obtained from optical absorption measurements and the transmission electron microscopy performances. It has been stated that the optical and structural characteristics of the doped specimens are effectively controlled by the dopant concentrations and parameters of both, the ion-exchange procedures and the annealing treatments

M. Suszynska; L. Krajczyk; B. Macalik

2010-01-01

391

Potential application of an electrodialysis pilot plant containing ion-exchange membranes in chromium removal  

Microsoft Academic Search

Exploration of a new working system to investigate the removal of chromium ions in its hexavalent oxidation state singly in connection with different parameters and associated moieties in feed mixtures was performed using an indigenously built electrodialysis (ED) pilot plant comprising a set of ion-exchange membranes. In order to check the efficacy of ED unit, parameters like applied potential, pH,

S. K. Nataraj; K. M. Hosamani; T. M. Aminabhavi

2007-01-01

392

Observations of Solar Wind Ion Charge Exchange in the Comet Halley Coma.  

National Technical Information Service (NTIS)

Giotto Ion Mass Spectrometer/High Energy Range Spectrometer (IMS/HERS) observations of solar wind ions show charge exchange effects and solar wind compositional changes in the coma of comet Halley. As the comet was approached, the He(++) to proton density...

S. A. Fuselier E. G. Shelley B. E. Goldstein R. Goldstein M. Neugebauer

1991-01-01

393

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

Microsoft Academic Search

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

Yasuhito Gotoh; Hiroshi Tsuji; Junzo Ishikawa

2001-01-01

394

Separation of hafnium from zirconium in sulfuric acid solutions using pressurized ion exchange  

SciTech Connect

High-resolution pressurized ion exchange has been used successfully to study and separate hafnium and zirconium sulfate complexes by chromatographic elution from Dowex 50W-X8 (15 to 25 ..mu..m) resin with sulfuric acid solutions. Techniques were developed to continuously monitor the column effluents for zirconium and hafnium by reaction with fluorometric and colorimetric reagents. Since neither reagent was specific for either metal ion, peak patterns were initially identified by using the stable isotopes /sup 90/Zr and /sup 180/Hf as fingerprints of their elution position. Distribution ratios for both zirconium and hafnium decrease as the inverse fourth power of the sulfuric acid concentration below 2N and as the inverse second power at higher acid concentration. The hafnium-to-zirconium separation factor is approximately constant (approx. 8) over the 0.5 to 3N range. Under certain conditions, an unseparated fraction was observed that was not retained by the resin. The amount of this fraction which is thought to be a polymeric hydrolysis product appears to be a function of metal and sulfuric acid concentrations. Conditions are being sought to give the highest zirconium concentration and the lowest acid concentration that can be used as a feed material for commercial scale-up in the continuous annular chromatographic (CAC) unit without formation of the polymer.

Hurst, F.J.

1981-01-01

395

Biomolecule Separations with Two New HPLC ion-Exchange Columns  

Microsoft Academic Search

Two new HPLC packing materials, Hydrophase HP-SAX and HP-SCX, based upon a macroporous hydrophilic polymer, have been developed for biomolecule separations. Hydrophase HP-SAX was developed by attaching quaternary nitrogen groups onto the surface of the base polymer for anion-exchange separations. HP-SCX was formed by attaching sulfonyl groups to the base polymer for cation-exchange chromatographic separations. Both HP-SAX and HP-SCX have

N. F. Nelson; N. Kitagawa

1990-01-01

396

Bromate removal in the ion-exchange process  

Microsoft Academic Search

To remove bromates from water, use was made of anion exchange in the process of Donnan dialysis conducted with an anion-exchange membrane. Under such conditions, the removal of bromates from a one-component solution was found to be very high (more than 90%). It was observed that the presence of accompanying anions (NO3? and HCO3?), whose concentrations were by several orders

Jacek A. Wi?niewski; Ma?gorzata Kabsch-Korbutowicz

2010-01-01

397

Improvement in both giant magnetoresistance and exchange bias through hydrogen ion irradiation at low energy  

SciTech Connect

Irradiation of IrMn-based spin valves with 550 eV hydrogen ions increased their giant magnetoresistance and exchange bias by 20% and 60%, respectively. This significant enhancement stems from the strong (111) texture and small mosaic spread of the IrMn antiferromagnet that resulted from the microstructural reconstruction caused by the energy transfer during the bombardment by hydrogen ions, as well as by the narrow dispersion in the exchange bias. Irradiation with the hydrogen ion at low energy can improve the properties of spin valves without resulting in undue degradation in the performance or the microstructure.

Shim, Jaechul; Han, Yoonsung; Lee, Jinwon; Hong, Jongill [Materials Science and Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

2008-09-01

398

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

PubMed

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

Lucy, Charles A

2003-06-01

399

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

PubMed Central

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

Mattox, Vernon R.; Litwiller, Robert D.; Goodrich, June E.

1972-01-01

400

CoMOR zeolite catalyst prepared by buffered ion exchange for effective decomposition of nitrous oxide.  

PubMed

Co contained MOR zeolite catalysts with high Co loadings were successfully synthesized by buffered ion exchange at pH 8, and were tested for N(2)O catalytic decomposition. The high exchange level of synthesized CoMOR(x)-BIE catalysts probably benefits from the maximizing hydroxycomplexes Co(OH)(+) ion in the buffered solution, which is more preferred for the ion exchange with the zeolites. It has been found that the novel CoMOR(x)-BIE catalysts exhibit excellent catalytic activities, which is attributed to the large population of isolated Co(2+) ions on ion exchange positions. The most active CoMOR(130)-BIE catalyst shows high resistance to the inhibition of oxygen, NO and water vapor. Furthermore, stability tests indicate that the CoMOR(130)-BIE catalyst has no obvious deactivation under simulated emission conditions after reaction for more than 100 h. This extraordinary durability could be related to its high Co(2+) content and low Brönsted acidity sites in the catalyst, which facilitate the stability of active isolated Co(2+) on ion exchange positions. Thus, the CoMOR(130)-BIE catalyst shows a great potential as a cost-effective catalyst for N(2)O elimination in future applications. PMID:21782332

Zhang, Xinyan; Shen, Qun; He, Chi; Wang, Yufei; Cheng, Jie; Hao, Zhengping

2011-07-08

401

Cerium doped soda-lime-silicate glasses: effects of silver ion-exchange on optical properties  

Microsoft Academic Search

Effects of silver ion-exchange on optical absorption (OA) and photoluminescence (PL) spectra of a cerium doped soda-lime-silicate glass at room temperature are investigated. The optical spectra are described in terms of the characteristic transitions 4f?5d originated in Ce3+ ions placed mainly in two different sites of the glass network. As Ag+ ions are introduced into the cerium doped glass, they

S. E Paje; M. A Garc??a; M. A Villegas; J Llopis

2001-01-01

402

Facilitated separation of a select gas through an ion exchange membrane  

Microsoft Academic Search

Suitable for separating COâ, HâS, olefins, etc., from a gas mixture, GE's selective purification process uses an ion-exchange membrane that has specific mobile counter-ions electrostatically retained in it. These counter-ions react reversibly with the specific gas molecules to be separated. Besides being highly selective, the membrane facilitates gas transport across it, thus accomplishing a separation superior to that of other

S. G. Kimura; W. J. Ward; S. L. Matson

1982-01-01

403

Investigation of the ion-exchange behaviour of titania: Application as a packing material for ion chromatography  

Microsoft Academic Search

Summary  Titania synthesized in this laboratory has previously been tested under reversed-phase conditions to assess its ion-exchange\\u000a behaviour. Although in reversed-phase chromatography with acetic acid-sodium acetate buffer as mobile phase titania behaved\\u000a as an anion-exchanger only, retention data suggested either that it behaved as a cation exchanger at higher mobile phase pH\\u000a or that the retention of cationic solutes was inhibited

K. Tani; Y. Suzuki

1997-01-01

404

Recent developments on ion-exchange membranes and electro-membrane processes.  

PubMed

Rapid growth of chemical and biotechnology in diversified areas fuels the demand for the need of reliable green technologies for the down stream processes, which include separation, purification and isolation of the molecules. Ion-exchange membrane technologies are non-hazardous in nature and being widely used not only for separation and purification but their application also extended towards energy conversion devices, storage batteries and sensors etc. Now there is a quite demand for the ion-exchange membrane with better selectivities, less electrical resistance, high chemical, mechanical and thermal stability as well as good durability. A lot of work has been done for the development of these types of ion-exchange membranes during the past twenty-five years. Herein we have reviewed the preparation of various types of ion-exchange membranes, their characterization and applications for different electro-membrane processes. Primary attention has been given to the chemical route used for the membrane preparation. Several general reactions used for the preparation of ion-exchange membranes were described. Methodologies used for the characterization of these membranes and their applications were also reviewed for the benefit of readers, so that they can get all information about the ion-exchange membranes at one platform. Although there are large number of reports available regarding preparations and applications of ion-exchange membranes more emphasis were predicted for the usefulness of these membranes or processes for solving certain type of industrial or social problems. More efforts are needed to bring many products or processes to pilot scale and extent their applications. PMID:16325751

Nagarale, R K; Gohil, G S; Shahi, Vinod K

2005-12-02

405

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

406

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

PubMed

In this paper the exchange of lanthanide(III) ions (Ln(3+)) between a solution and a coordination polymer (CP) of di(2-ethylhexyl)phosphoric acid (Hdehp), [Ln(dehp)3], is studied. Kinetic and selectivity studies suggest that a polymeric network of [Ln(dehp)3] has different characteristics than the corresponding monomeric complex. The reaction rate is remarkably slow and requires over 600h to reach in nearly equilibrium, and this can be explained by the polymeric crystalline structure and high valency of Ln(3+). The affinity of the exchange reaction reaches a maximum with the Ln(3+) possessing an ionic radius 7% smaller than that of the central Ln(3+), therefore, the affinity of the [Ln(dehp)3] is tunable based on the choice of the central metal ion. Such unique affinity, which differs from the monomeric complex, can be explained by two factors: the coordination preference and steric strain caused by the polymeric structure. The latter likely becomes predominant for Ln(3+) exchange when the ionic radius of the ion in solution is smaller than the original Ln(3+) by more than 7%. Structural studies suggest that the incoming Ln(3+) forms a new phase though an exchange reaction, and this could plausibly cause the structural strain. PMID:24183431

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

2013-09-25

407

Development of urethane acrylate composite ion-exchange membranes and their electrochemical characterization.  

PubMed

With the objective of introducing antifouling characteristics into interpolymer types of cation and anion exchange membranes, the surface of these membranes was coated with a 12-microm-thick urethane acrylate layer and was cured by UV radiation of wavelengths 308 and 172 nm under a complete inert atmosphere. Different urethane acrylate composite ion exchange membranes developed were characterized in NaCl solution by measuring their ion-exchange capacity, volume fraction of water, contact angle with water, membrane conductance, and membrane potential. It was found that the electrochemical transport properties of urethane acrylate composite cation-exchange membranes were increased due to resonance stabilization of the urethane group, which acts as a weak acid and dissociates as a negatively charged urethane ion and a positively charged proton. This contributes toward the net charge density of the membrane matrix responsible for enhanced selectivity and conductivity, while for urethane acrylate composite anion-exchange membranes reduction in net charge density was responsible for reduction in electrochemical transport properties. Counterion transport number, permselectivity, and counterion diffusion coefficient values for these membranes were also estimated. Experiments were also carried out in higher homologs of sodium carboxylate solutions in order to observe the fouling tendencies of these membranes. It was concluded that it is possible to obtain antifouling characteristics of ion-exchange membranes by coating and curing thin hydrophilic layers of urethane acrylate on their surfaces without sacrificing their electrochemical transport properties. PMID:14697712

Nagarale, R K; Shahi, Vinod K; Schubert, Rolf; Rangarajan, R; Mehnert, R

2004-02-15

408

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

SciTech Connect

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

Benson, L.V.

1980-05-01

409

Use of Ion exchange membranes in routine soil testing  

Microsoft Academic Search

We developed and assessed a method for simultaneous extraction of plant available nitrogen, phosphorus, sulfur and potassium using anion and cation exchange membranes (ACEM). The technique was found to be highly suitable for routine soil testing due to its simplicity, rapidness and accuracy. The study compared the amount of nutrients extracted by ACEM with conventional chemical?based extractants for P and

P. Qian; J. J. Schoenau; W. Z. Huang

1992-01-01

410

Kilogram-Scale Purification of Americium by Ion Exchange.  

National Technical Information Service (NTIS)

Sequential anion and cation exchange processes have been used for the final purification of exp 241 Am recovered during the reprocessing of aged plutonium metallurgical scrap. Plutonium was removed by absorption of Dowex 1, X-3.5 (30 to 50 mesh) anion exc...

E. J. Wheelwright

1979-01-01

411

Regeneration of nano-ZnO photocatalyst by the means of soft-mechanochemical ion exchange method  

Microsoft Academic Search

Nano-crystalline ZnO particles synthesized via an ion exchange method were used in a methyl-orange photocatalytic degradation process. An ion exchange resin mixed bed system was used in the suspension for separation of nano-ZnO and methyl-orange after photocatalysis reaction. Ion exchange resin, photocatalyst and water were mixed evenly by airflow. Nano-ZnO photocatalyst and soluble carboxyl zinc were gathered in the soft-mechanochemical

Yansheng LI; Zhenhua JIAO; Nan YANG; Hong GAO

2009-01-01

412

Comparison of isotherms for the ion exchange of Pb(II) from aqueous solution onto homoionic clinoptilolite  

Microsoft Academic Search

The ion exchange equilibrium of Pb(II) on clinoptilolite modified with NH4Cl and NaCl can be represented by two types of isotherms. The first one is the ion exchange isotherm based upon the constant of thermodynamic equilibrium for the ion exchange reaction; however, the fitting procedure for this isotherm can be very tedious due to all the calculations involved and additional

M. S. Berber-Mendoza; R. Leyva-Ramos; P. Alonso-Davila; L. Fuentes-Rubio; R. M. Guerrero-Coronado

2006-01-01

413

Ion exchange and dissolution/precipitation modeling; Application to the injection of aqueous fluids into a reservoir sandstone  

SciTech Connect

Ion exchange and dissolution/precipitation processes are of considerable concern when aqueous fluids are injected into reservoir sandstones, as in waterflooding or alkaline flooding or in well treatments. This paper describes a flow model that takes into account several ion exchange equilibria and the precipitation/dissolution of carbonates and hydroxides. Its validity is tested through simulations of laboratory experiments dealing with brine and alkali injection. Some insights into the effects of ion exchange and precipitation on flow properties are given.

Bazin, B.; Labrid, J. (Inst. Francais du Petrole (FR))

1991-05-01

414

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

PubMed Central

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

2012-01-01

415

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

PubMed Central

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

Wagh, Vijay D.; Pawar, Nilesh

2012-01-01

416

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

PubMed

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

Wagh, Vijay D; Pawar, Nilesh

2012-06-18

417

Monte Carlo simulations on the water-to-air stopping power ratio for carbon ion dosimetry  

SciTech Connect

Many papers discussed the I value for water given by the ICRU, concluding that a value of about 80{+-}2 eV instead of 67.2 eV would reproduce measured ion depth-dose curves. A change in the I value for water would have an effect on the stopping power and, hence, on the water-to-air stopping power ratio, which is important in clinical dosimetry of proton and ion beams. For energies ranging from 50 to 330 MeV/u and for one spread out Bragg peak, the authors compare the impact of the I value on the water-to-air stopping power ratio. The authors calculate ratios from different ICRU stopping power tables and ICRU reports. The stopping power ratio is calculated via track-length dose calculation with SHIELD-HIT07. In the calculations, the stopping power ratio is reduced to a value of 1.119 in the plateau region as compared to the cited value of 1.13 in IAEA TRS-398. At low energies the stopping power ratio increases by up to 6% in the last few tenths of a mm toward the Bragg peak. For a spread out Bragg peak of 13.5 mm width at 130 mm depth, the stopping power ratio increases by about 1% toward the distal end.

Henkner, Katrin; Bassler, Niels; Sobolevsky, Nikolai; Jaekel, Oliver [Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg 69120 (Germany); Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg 69120 (Germany); Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus 8000 (Denmark) and Department of Clinical Radiation Oncology, University of Heidelberg, Heidelberg 69120 (Germany); Department of Neutron Research, Institute for Nuclear Research of the Russian Academy of Sciences, Moscow 117312 (Russian Federation); Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg 69120 (Germany) and Heidelberg Ion Beam Therapy Center (HIT), Heidelberg University Hospital, Heidelberg 69120 (Germany)

2009-04-15

418

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

SciTech Connect

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

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

1983-10-01

419

Rapid and Highly Sensitive Detection of Bacteria Sensor Using a Porous Ion Exchange Film  

NASA Astrophysics Data System (ADS)

A biological and chemical sensor with a rapid response in microlevel tests is required for health and environmental monitoring. Our approach to developing a high-performance sensor is to use a porous monolith-type ion exchanger having three-dimensional acceptors to sense bacteria. This porous monolith-type ion exchanger has an open-cellular structure with 5-50-?m-diameter pores. The concentration of bacteria in the solution can be detected by measuring the impedance of the monolith. We have succeeded in sensing bacteria Bacillus subtilis with a concentration as low as 8× 102 cells/ml. The porous ion exchanger is a potential high-performance device for biological and chemical sensing.

Miyano, Kazuki; Aoki, Hidemitsu; Hotta, Saori; Fujiwara, Nobuaki; Masui, Akihiko; Yano, Daisaku; Sano, Kazuhiko; Yamanaka, Koji; Jeong, Jong-Hyeon; Kimura, Chiharu; Sugino, Takashi

2008-04-01

420

Structural changes of soda-lime silica glass induced by a two-step ion exchange  

NASA Astrophysics Data System (ADS)

Introduction of silver or copper ions in soda-lime silica glass has been investigated by studying the data obtained from optical absorption measurements and the transmission electron microscopy performances. It has been stated that the optical and structural characteristics of the doped specimens are effectively controlled by the dopant concentrations and parameters of both, the ion-exchange procedures and the annealing treatments applied afterwards. By sequential ion exchange of as received specimens in molten baths of Cu2Cl2 and (AgNO3 in NaNO3), the composition and electronic structure of the elemental-nanoclusters have been altered. Moreover, depending on the order of annealing, different microstructures were created in the fabricated composites. Like this, the two-step exchange determines a new engineering way new materials with desired optical properties could be produced.

Suszynska, M.; Krajczyk, L.; Macalik, B.

2010-11-01

421

Radiolytic and chemical degradation of strong acidic ion-exchange resins: Study of ligands formed  

Microsoft Academic Search

The formation of water-soluble organic ligands by radiolytic and chemical degradation of several strong acidic ion-exchange resins was investigated under conditions close to those of the near field of a cementitious repository. The most important degradation products were studied and their complexing properties evaluated. Irradiation of strong acidic cation exchange resins (Powder PCH and Lewatite S-100) resulted in the formation

L. R. van Loon; W. Hummel

1999-01-01

422

SuperLig(TM) 644 Ion Exchange Resin Stability in Nitric Acid at Elevated Temperatures  

Microsoft Academic Search

In the Hanford River Protection Project Waste Treatment Plan (RPP-WTP) flowsheet, opportunity exists for the organic SuperLig 644(TM) cation exchange resin to come in contact with concentrated (5 M) nitric acid at elevated temperatures in the acid recovery evaporator. These are similar conditions where other ion exchange resin (albeit usually anion) column explosions have occurred. The objective of these tests

2003-01-01

423

Desalination of Saline Sludges Using Ion-Exchange Column with Zeolite  

Microsoft Academic Search

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

A. E. Ghaly; M. Verma

2008-01-01

424

Microstructure and silver nanoparticles in ion-exchanged and deformed soda-lime silicate glasses  

Microsoft Academic Search

Optical absorption, microspectrophotometry, thermally stimulated depolarization current, and transmission electron microscopy were applied to a commercial multicomponent soda-lime silicate glass subjected to the Na+?Ag+ ion-exchange, annealing in air or hydrogen, and to mechanical stretching. The treatments affect both the matrix microstructure and the morphology of the silver particles. Mechanical stretching of the exchanged specimens annealed in hydrogen induces the most

M. Suszynska; L. Krajczyk; R. Capelletti; A. Baraldi; K. J. Berg

2003-01-01

425

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

SciTech Connect

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

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

2008-04-15

426

SEPARATION OF PLUTONIUM FROM AQUEOUS SOLUTIONS BY ION-EXCHANGE  

DOEpatents

A process is described for the separation of plutonium from an aqueous solution of a plutonium salt, which comprises adding to the solution an acid of the group consisting of sulfuric acid, phosphoric acid, and oxalic acid, and mixtures thereof to provide an acid concentration between 0.0001 and 1 M, contacting the resultant solution with a synthetic organic anion exchange resin, and separating the aqueous phase and the resin which contains the plutonium.

Schubert, J.

1958-06-01

427

Subcellular imaging of calcium exchange in cultured cells with ion microscopy.  

PubMed

Calcium to calcium exchange between intracellular and extracellular pools has been imaged directly in individual cells using stable 44Ca (98.78% enrichment) in the nutrient medium and an isotopic imaging technique, ion microscopy. Observations were made by imaging mass 40 to determine the native intracellular calcium (40Ca), and mass 44 to localize the 44Ca from the extracellular medium that exchanged with cellular calcium. LLC-PK1 porcine kidney epithelial cells were exposed to the nutrient medium with 1.87 mM stable 44Ca for 0, 1, 2, 5, 8, 20, 60 and 90 min, and cryogenically prepared prior to ion microscopic analysis. The cell nucleus, the Golgi region and the remaining cell cytoplasm could be spatially resolved to within about 0.5 microns using the ion microscope. On the basis of the kinetics of 40Ca to 44Ca exchange it was observed that all three compartments had a rapidly exchanging pool of calcium, which took about 2 min to exchange. A moderately rapidly exchanging pool of calcium was identified between 2 and 20 min of calcium exchange. The cells had exchanged about 50% of their total internal calcium with the external calcium in less than 20 min. The remaining 50% of the cellular calcium could be classified as a slowly exchanging pool. Isotopic images of 39K and 23Na were recorded along with 40Ca and 44Ca images to assess the health status of the cell. Isotopic imaging has the unique ability to distinguish intracellular calcium from the extracellular calcium that enters cells and has enormous potential for studies of calcium transport under physiological and pathological conditions. PMID:1506424

Chandra, S; Ausserer, W A; Morrison, G H

1992-07-01

428

Systemic acid load from the diet affects maximal exercise respiratory exchange ratio  

PubMed Central

Background A maximal exercise respiratory exchange ratio (RERmax) ?1.10 is commonly used as a criterion to determine if a “true” maximal oxygen uptake (VO2max) has been attained during maximal-effort exercise testing. Because RERmax is heavily influenced by CO2 production from acid buffering during maximal exercise, we postulated that dietary acid load, which affects acid-base regulation, might contribute to variability in RERmax. Purpose To determine if a habitual dietary intake that promotes systemic alkalinity results in higher RERmax during VO2max testing. Methods Sedentary men and women (47-63y, n=57) with no evidence of cardiovascular disease underwent maximal graded treadmill exercise tests. VO2max and RERmax were measured with indirect calorimetry. Habitual diet was assessed for its long-term effect on systemic acid-base status by performing nutrient analysis of food diaries and using this information to calculate the potential renal acid load (PRAL). Participants were grouped into tertiles based on PRAL. Results The lowest PRAL tertile (alkaline PRAL) had higher RERmax values (1.21±0.01, p?0.05) than the middle tertile (1.17±0.01) and highest PRAL tertile (1.15±0.01). There were no significant differences (all p?0.30) among PRAL tertiles for RER at submaximal exercise intensities of 70%, 80%, or 90% VO2max. After controlling for age, sex, VO2max, and maximal heart rate (HRmax), regression analysis demonstrated that 19% of the variability in RERmax was attributed to PRAL (r=?0.43, p=0.001). Unexpectedly, HRmax was lower (p?0.05) in the low PRAL tertile (164±3 beats/min) versus the highest PRAL tertile (173±3 beats/min). Conclusion These results suggest that individuals on a diet that promotes systemic alkalinity may more easily achieve the RERmax criterion of ?1.10 which might lead to false-positive conclusions about achieving maximal effort and VO2max during graded exercise testing.

Niekamp, Katherine; Zavorsky, Gerald S.; Fontana, Luigi; McDaniel, Jennifer L; Villareal, Dennis T; Weiss, Edward P

2013-01-01

429

Ion exchange and electrochemical evaluation of the microporous phosphate Li 9Fe 7(PO 4) 10  

Microsoft Academic Search

A new lithium iron(III) phosphate, Li9Fe7(PO4)10, has been synthesized and is currently under electrochemical evaluation as an anode material for rechargeable lithium-ion battery applications. The sample was prepared via the ion exchange reaction of Cs5K4Fe7(PO4)101 in the 1M LiNO3 solution under hydrothermal conditions at 200°C. The fully Li+-exchanged sample Li9Fe7(PO4)102 cannot yet be synthesized by conventional high-temperature, solid-state methods. The

Gregory A. Becht; John T. Vaughey; Robin L. Britt; Cassandra T. Eagle; Shiou-Jyh Hwu

2008-01-01

430

Fractionation of Aspergillus niger cellulases by combined ion exchange affinity chromatography  

SciTech Connect

Eight chemically modified cellulose supports were tested for their ability to adsorb components of the Aspergillus niger cellulase system. At least two of the most effective adsorbents, aminoethyl cellulose and carboxymethyl cellulose, were shown to be useful for the fractionation of cellulases. These supports apparently owe their resolving capacity to both ion exchange and biospecific binding effects; however, the relative importance of each effect is unknown. These observations form the basis for a new cellulase fractionation technique, combined ion exchange-affinity chromatography. 22 references.

Boyer, R.F.; Allen, T.L.; Dykema, P.A.

1987-02-05

431

Cation-exchange of metal ions in organic solvent-cupferron media.  

PubMed

Distribution coefficients of 20 metal ions were determined on the strongly acidic cation-exchanger Dowex 50 in a 30:7:1 mixture of chloroform-methanol-lM hydrochloric acid which was 0.1M in cupferron. In this system the distribution coefficients of Fe(in), Ti(TV), Cu(II), Ce(III) and Th are lower by several orders of magnitude than those of Ni, Mn(II), Cd, Co(II), Ca, U(VI), and Sr. It is possible to separate these two groups of elements on an ion-exchange column. PMID:18961228

Korkisch, J; Khater, M M

1972-12-01

432

Effects of ion exchange on hardness and fracture toughness of dental ceramics.  

PubMed

Dental ceramics generally fail because of the growth of microscopic surface flaws that form during processing or finishing or that result from surface impact during service. The ion-exchange process has been shown to be effective in improving the flexural strength of most dental porcelains through the development of a compressive surface layer. The Vickers hardness and crack resistance of several commercial dental ceramics were determined by indentation techniques. The results of this investigation indicate that ion-exchange reinforcement can significantly improve the resistance of the ceramic surface to crack propagation with little effect on apparent surface hardness. PMID:1520452

Seghi, R R; Denry, I; Brajevic, F

433

Monodisperse porous polymer particles with polyionic ligands for ion exchange separation of proteins  

Microsoft Academic Search

A new “grafting to” strategy was proposed for the preparation of polymer based ion exchange supports carrying polymeric ligands in the form of weak or strong ion exchangers. Monodisperse porous poly(glycidyl methacrylate-co-ethylene dimethacrylate), poly(GMA-co-EDM) particles 5.9?m in size were synthesized by “modified seeded polymerization”. Poly(2,3-dihydroxypropyl methacrylate-co-ethylene dimethacrylate), poly(DHPM-co-EDM) particles were then obtained by the acidic hydrolysis of poly(GMA-co-EDM) particles. The

Ender Unsal; Ta?k?n Irmak; Elifnaz Durusoy; Mürvet Tuncel; Ali Tuncel

2006-01-01

434

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

SciTech Connect

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

Nash, C.; Duignan, M.

2010-01-14

435

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

SciTech Connect

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

Hassan, N.M.

2000-07-27

436

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

SciTech Connect

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

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

2003-04-09

437

Evaluation of Sulfonated Rubber Powder as Ion Exchange Resin  

Microsoft Academic Search

Ground rubber powder was treated with both concentrated sulfuric acid and chlorosulfonic acid. The treatment conditions as well as the parameters affecting the degree of sulfonation were investigated. It is assumed that the sulfonation reaction occurs on the benzene ring as well as on the double bond of the butadiene unit in styrene butadiene rubber (SBR). Evaluation of the ion

A. A. Yehia; M. N. Ismail; Y. A. Hefny; E. M. Abdel-Bary; M. A. Mull

2002-01-01

438

Studies of negative ions by collision-induced decomposition and hydrogen-deuterium exchange techniques.  

PubMed Central

Development of two new techniques for studying the gas phase chemistry of negative ions is reported. Collision induced dissociation (CID) of (M-1)- ions has been accomplished in a newly constructed triple stage quadrupole mass spectrometer. This instrument was assembled by adding two additional Finnigan quadrupole mass filters to a Finnigan Model 3200 CI mass spectrometer. Generation of (M-1)- ions is accomplished by allowing OH- and sample to react under CI conditions in the ion source. The first quadrupole mass filter, Q1, is then employed to selectively pass the (M-1)- ion into a second quadrupole filter containing argon or neon at 10(-3) torr. On collision with the inert gas the (M-1)- ions dissociate into fragments which are then mass analyzed in the third quadrupole filter, CID spectra of (M-1)- ions from twelve carbonyl compounds are presented in this paper. Ion molecule isotope exchange reactions in the CI ion source can be used to count the number of hydrogen atoms in many different chemical environments. Collisions between sample (M-1)- ions and deuterium-labeled reagent gases (ND3, D2O, EtOD) facilitate incorporation of deuterium into the negative ion if the basicities of the sample and reagent anions are similar. Thus it is possible to selectively incorporate deuterium into many organic samples by controlling the exothermicity of the acid base, ion-molecule chemistry.

Hunt, D F; Sethi, S K; Shabanowitz, J

1980-01-01

439

The delivery of ketoprofen from a system containing ion-exchange fibers.  

PubMed

A postulated model for transdermal delivery using ion-exchange fibers as controlling device was designed, and the main objective of this study was to assess the rationality of the model. The release rates of ketoprofen from the carbopol-based gel vehicles containing ion-exchange fibers to which the ketoprofen had been bound have been determined across 0.22 microm microporous membrane. The fluctuation of the release rate of ketoprofen from the vehicles was much lower compared with that of simple gels, though the cumulative amount of ketoprofen delivery was less. Additional ions could increase the rate and extent of ketoprofen delivery. The iontophoretically assisted transport of ketoprofen across rat skin was also studied and found to be favorable to ketoprofen permeation. According to the tested model, the ion-layer could enhance the ketoprofen delivery and satisfactory results were achieved. PMID:16701973

Yu, Limin; Li, Sanming; Yuan, Yue; Dai, Yi; Liu, Hongzhuo

2006-04-01

440

Energy loss and charge exchange processes of high energy heavy ions channeled in crystals  

SciTech Connect

The interaction of moving ions with single crystals is very sensitive to the orientation of the incident beam with respect to the crystalline directions of the target. Our experiments show that high energy heavy ion channeling deeply modifies their slowing down and charge exchange processes. This is due to the fact that channeled ions interact only with outershell target electrons, which means that the electron density they experience is very low and that the binding energy, and then the momentum distribution of these electrons, are quite different from the corresponding average values associated to random incidence. The two experimental studies presented here show the reduction of the energy loss rate for fast channeled heavy ions and illustrate the two aspects of channeling effects on charge exchange, the reduction of electron loss on one hand, and of electron capture on the other hand.

Poizat, J.C.; Andriamonje, S.; Anne, R.; Faria, N.V.d.C.; Chevallier, M.; Cohen, C.; Dural, J.; Farizon-Mazuy, B.; Gaillard, M.J.; Genre, R.; Hage-Ali, M.; Kirsch, R.; L'hoir, A.; Mory, J.; Moulin, J.; Quere, Y.; Remillieux, J.; Schmaus, D.; Toulemonde, M. (Institut de Physique Nucleaire de Lyon, IN2P3-CNRS/Universite Claude Bernard, 43, Bd du11 Novembre 1918, 69622 Villeurbanne Cedex (France) Centre d'Etudes Nucleaires de Bordeaux (and IN2P3) 33170 Gradignan (France) GANIL (IN2P3), 14021 Caen Cedex (France) Groupe de Physique des Solides de l'Ecole Normale Superieure 75251 Paris Cedex (France) Centre Interdisciplinaire de Recherches avec les Ions Lourds 14040 Caen Cedex (France) Groupe de Physique Appliquee aux Semiconducteurs, Centre de Recherches Nucleaires (and IN2P3) 67037 Strasbourg Cedex (France) Laboratoire des Solides Irradies, Ecole Polytechnique 91128-Palaiseau Cedex (France))

1990-06-01

441

High proton ratio plasma production in a small negative ion source  

NASA Astrophysics Data System (ADS)

A proton ratio was measured in the small (1.4 l) arc discharge multicusp source at a pressure of 1.4 Pa. A measured proton ratio in an extracted positive ion beam was 50%. By applying the transverse magnetic field as the magnetic filter in the source, the proton ratio drastically increased to 90% even in such a small source. To clarify the proton production processes, coupled rate equations were numerically solved to estimate particle (H+, H2+, H3+, and H0) densities in the various size of ion source. It has been clarified that a main proton production process is different with the source size. In the large size source, which has better confinement of the source plasma, the ionization of H atom becomes effective to increase the proton yield. In the small ion source, the dissociation of H2+ (H2++e-->H++H+e) is the dominant process for the proton production. By adopting the magnetic filter in the small source, H2+ production by primary electron impact is suppressed in the extraction region. Molecular ions are dissociated or neutralized by thermal electrons in the extraction region. The main process of the proton production H2++e-->H++H+e has the large cross section with the low temperature electrons, thus the high proton yield beam can be extracted.

Morishita, T.; Inoue, T.; Iga, T.; Watanabe, K.; Imai, T.

2004-05-01

442

Correlating exchange bias with magnetic anisotropy in ion-beam bombarded NiFe/Mn-oxide bilayers  

NASA Astrophysics Data System (ADS)

The exchange bias field dependence on the Mn-oxide and its microstructure in NiFe/Mn-oxide bilayers was investigated. Transmission electron microscopy results have shown that the bilayer bottom consisted of either ?-Mn, rocksalt MnO, or a composite of tetragonal Mn3O4+MnO, depending on the ratio of O2/Ar used during dual ion-beam deposition. Magnetometry results at 5 K indicate that the exchange bias field (Hex~-300 Oe) is largest in a NiFe/Mn (0%O2/Ar) bilayer. The MnO formation by in situ Mn oxidation results in a decrease in Hex in a NiFe/Mn-oxide (21%O2/Ar) bilayer. In contrast, a further increase in the O2/Ar ratio during deposition results in larger Hex and Hc. This is attributed to the oxidation of MnO into a harder ferrimagnet, Mn3O4. Our results indicate that the antiferromagnetic Mn enabled stronger coupling with NiFe than MnO. In addition, we find that the MnO-Mn3O4 coupling dominates the exchange bias effects at high oxygen concentrations.

Lin, K.-W.; Guo, J.-Y.; Chen, T.-J.; Ouyang, H.; Vass, E.; van Lierop, J.

2008-12-01

443

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

SciTech Connect

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

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

1986-05-10

444

Solar Wind Charge Exchange Studies Of Highly Charged Ions On Atomic Hydrogen  

Microsoft Academic Search

Accurate studies of low-energy charge exchange (CX) are critical to understanding underlying soft X-ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H-like, and He-like ions of C, N, O

I. N. Draganic´; D. G. Seely; D. McCammon; C. C. Havener

2011-01-01

445

Time evolution of the mass exchange in grazing heavy-ion collisions  

Microsoft Academic Search

On the basis of a macroscopical approach to the description of two interpenetrating quantal objects, the equations of two-fluid\\u000a hydrodynamics for the cohesion stage of deeply inelastic heavy-ion collisions are formulated. The elasticity of the ions is\\u000a analyzed in peripheral mass exchange reactions at intermediate energies. The system of closed equations of Newtonian mechanics,\\u000a which simultaneously describes the motion of

S. I. Bastrukov; F. Deák; A. Kiss; Z. Seres

1991-01-01

446

Kinetics of adsorption of Co(II) removal from water and wastewater by ion exchange resins  

Microsoft Academic Search

The capacity of ion exchange resins, IRN77 and SKN1, for removal of cobalt from aqueous solution has been investigated under different conditions namely initial solution pH, initial metal-ion concentration, and contact time. The equilibrium data obtained in this study have been found to fit both the Langmuir and Freundlich adsorption isotherms. The adsorption of Co(II) on these resins follows first-order

S. Rengaraj; Seung-Hyeon Moon

2002-01-01

447

A simple ion-exchange resin procedure for extracting plant-available elements from soil  

Microsoft Academic Search

A simplified procedure for extracting ions from soil with ion-exchange resins is reported. The resin, placed in nylon-netting bags, were immersed in soil suspensions and shaken. Compared to the conventional procedure, where the resin beads are freely suspended in the soil-water mixture, this bag-procedure allowed quicker separation of resin from the soil suspensions. Furthermore, the severe soil grinding as done

E. Sibbesen

1977-01-01

448

Calculation of Charge Exchange in Potassium Ions/atoms Scattered from Metal Surfaces  

NASA Astrophysics Data System (ADS)

The charge-exchange processes of K ions/atoms scattered from metal surface are discussed in terms of the time-dependent Newns-Anderson quantum model with intra-atomic Coulomb interaction. The final charge-states distribution is calculated as a function of work function of the surfaces. The calculated results are compared with the experimental data. Furthermore, the probabilities of charge states of the moving K ions/atoms approaching to and leaving from the surface are demonstrated.

Pan, Limin; Wang, Yansen; Huang, Fayang; Tang, Jiayong; Yang, Fujia

449

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

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

450

A comparison of various ion exchange resins for the removal of ferric ions from copper electrowinning electrolyte solutions Part II: Electrolytes containing antimony and bismuth  

Microsoft Academic Search

Four commercially available ion exchange resins were tested to compare their ability to remove ferric from copper electrowinning electrolytes containing antimony and bismuth. Ion exchange batch tests were performed in the initial phase of the study and indicated that all resins tested co-loaded some antimony with the ferric. The aminophosphonic resin tested was the only resin to load a significant

Bethan McKevitt; David Dreisinger

2009-01-01

451

Copper effects on ion transport across lamprey erythrocyte membrane: Cl(-)/OH(-) exchange induced by cuprous ions.  

PubMed

We studied the effects of prelytic copper concentrations on cell volume, intracellular pH, and ion transport in lamprey erythrocytes. Ion fluxes and pH were measured by radioactive tracer technique, patch clamp, and flame photometry. Prelytic CuSO(4) concentration of 100 microM caused anion-dependent intracellular acidification and increase in Cl(-) influx after 2 min lag-phase. In the presence of ascorbate copper effect was amplified and lag-phase was skipped. Pretreatment of the cells with N-phenyl maleimide abolished copper-induced changes completely. Copper treatment caused an increase in Na(+) fluxes in both directions and a net Na(+) uptake. Copper-induced Na(+) transport was partially amiloride(MIA)-sensitive representing Na(+)/H(+) exchange. The nature of the amiloride-insensitive fraction of copper-activated Na(+) influx remains unknown. Cell swelling after 15 min of copper exposure induced regulatory volume decrease response involving KCl extrusion via K(+) and Cl(-) volume-sensitive channels. We suggest that the effects of copper on ion transport fit the following sequence of events: (i) cupric ions are reduced to cuprous state on the membrane surface, (ii) electroneutral pairs CuCl and CuOH mediate chloride/hydroxyl exchange, as shown before for trialkyltin, dissipating transmembrane pH gradient, and (iii) changes in intracellular pH result in the activation of the Na(+)/H(+) exchange and consecutive volume changes cause the RVD response. PMID:10486307

Bogdanova, A Y; Virkki, L V; Gusev, G P; Nikinmaa, M

1999-09-15

452

Effect of quark exchange on the structure function of A = 3 mirror nuclei and neutron\\/proton structure function ratio  

Microsoft Academic Search

By using quark-exchange formalism and realistic Faddeev wave functions, we investigate deep inelastic electron scattering from A = 3 mirror nuclei. The initial valence quarks input are taken from the GRV's calculations on F2P(x, Q2) which gives very good fit to the available data in the (x, Q2)-plane. It is shown that the free neutron to proton structure functions ratio

F. Zolfagharpour; M. Modarres; M. M. Yazdanpanah

2005-01-01

453

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

SciTech Connect

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

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

2012-09-15

454

Ion-exchange of monovalent and bivalent cations with NaA zeolite membranes : a molecular dynamics study  

NASA Astrophysics Data System (ADS)

Molecular simulations using the method of molecular dynamics have been carried out to study the dynamics and energetics of ion exchanges between monovalent and bivalent cations in supercritical and subcritical (liquid) electrolyte solutions (here Li+, and Ca++ in aqueous solutions of LiCl and CaCl2) and an ion exchange membrane (NaA zeolite) using direct simulations of up to a nanosecond or more. NaA zeolites are widely used in many commercial ion-exchange processes including detergents. Results show that with appropriate driving forces, such ion exchange processes can be clearly witnessed and investigated using molecular simulations at these timescales, especially for supercritical solutions. An attempt is made to understand the phenomenon of ion exchange at the molecular level. Results have shown that the ion-exchange process is primarily energetically driven and entropic forces do not appear to be playing a significant role in the exchanges observed. For supercritical LiCl solutions, small differences were found between the energy of the Li+ inside and outside the membrane. In contrast, for Na+ there was a considerable energetic advantage in being outside the membrane, making the overall exchange process energetically favourable. In subcritical (liquid) LiCl solutions an exchange was found to be more favourable energetically than supercritical solutions. For Ca++ similar trends were observed, except the differences in the energies were much larger (compared to the corresponding Li+ exchanges), making them more energetically efficient, as has also been observed experimentally. In addition to clarifying the molecular basis for these exchanges, simulations can also potentially be very useful to determine the behaviour (e.g. state dependence, etc.) of hydrodynamic parameters commonly used to characterize ion-exchange processes at a fundamental molecular level, and to determine if the hydrodynamic equations used for ion-exchange processes are applicable to nano-systems that can be studied using simulations.

Murad, S.; Jia, W.; Krishnamurthy, M.

2004-01-01

455

A Lagrangian Model to Predict the Modification of Near-Surface Scalar Mixing Ratios and Air–Water Exchange Fluxes in Offshore Flow  

Microsoft Academic Search

A model was developed to predict the modification with fetch in offshore flow of mixing ratio, air–water exchange flux, and\\u000a near-surface vertical gradients in mixing ratio of a scalar due to air–water exchange. The model was developed for planning\\u000a and interpretation of air–water exchange flux measurements in the coastal zone. The Lagrangian model applies a mass balance\\u000a over the internal

Mark D. Rowe; Judith A. Perlinger; Christopher W. Fairall

2011-01-01

456

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

SciTech Connect

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

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

2003-08-26

457

Radium-thorium disequilibrium and zeolite-water ion exchange in a Yellowstone hydrothermal environment  

SciTech Connect

Whole rock samples of hydrothermally altered Biscuit Basin rhyolite from Yellowstone drill cores Y-7 and Y-8 were analyzed for {sup 226}Ra and {sup 230}Th to determine the extent of radioactive disequilibrium and its relation to the rates and mechanisms of element transport in the shallow portion of an active hydrothermal system. The ({sup 226}Ra/{sup 230}Th) activity ratios range from 0.73 to 1.46 and are generally correlated with Th-normalized Ba concentrations (Ba{sub N}). Compositions of clinoptilolite and mordenite in these samples are consistent with ion exchange equilibrium between zeolites and coexisting thermal waters. Average K{sup Ba}{sub d mineral-water} values are 1.0 {center dot} 10{sup 5} mL/g for clinoptilolite and 1.4 {center dot} 10{sup 4} mL/g for mordenite. Apparent diffusivities through matrix porosity estimated for R and Ba range from {approximately}10{sup {minus}12} to {approximately}10{sup {minus}10} cm{sup 2} s{sup {minus}1} in thoroughly zeolitic rhyolite; these rates of diffusion are too low to account for the observed distance scale of ({sup 226}Ra/{sup 230}Th) disequilibrium. The correlated values of ({sup 226}Ra/{sup 230}Th) disequilibrium and Ba{sub N} represent zeolite-water ion exchange equilibrium that is caused by porous flow of water through the rock matrix and by the relatively rapid diffusion of cations within the zeolite lattices. A water flux of at least {approximately}2.5 (cm{sup 3}{sub water}/cm{sup 3}{sub rock}) yr{sup {minus}1} is required to produce measurable ({sup 226}Ra/{sup 230}Th) disequilibrium, whereas at least {approximately}23 (cm{sup 3}{sub water}/cm{sup 3}{sub rock}) yr{sup {minus}1} is required for the sample exhibiting the most extreme ({sup 226}Ra/{sup 230}Th) disequilibrium; these fluxes are much higher than those that can be inferred from net mass transfers of stable species.

Sturchio, N.C.; Bohlke, J.K. (Argonne National Laboratory, IL (USA)); Binz, C.M. (Loras College, Dubuque, IA (USA))

1989-05-01

458

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

SciTech Connect

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

Walker, D.D.

1999-01-15

459

Development of a Waste Water Regenerative System - Using Sphagnum Moss Ion-exchange  

NASA Astrophysics Data System (ADS)

The use of inexpensive, light weight and regenerative systems in an enclosed environment is of great importance to sustained existence in such habitats as the International Space Station, Moon or even Mars. Many systems exist which utilise various synthetic ion exchangers to complete the process of waste water clean-up. These systems do have a very good exchange rate for cations but a very low exchange rate for anions. They also have a maximum capacity before they need regeneration. This research proposes a natural alternative to these synthetic ion-exchangers that utilises one of natures greatest ion-exchangers, that of Sphagnum Moss. Sphagna can be predominantly found in the nutrient poor environment of Raised Bogs, a type of isolated wetland with characteristic low pH and little interaction with the surrounding water table. All nutrients come from precipitation. The sphagna have developed as the bog's sponges, soaking up all available nutrients (both cation & anion) from the precipitation and eventually distributing them to the surrounding flora and fauna, through the water. The goal of this research is to use this ability in the processing of waste water from systems similar to isolated microgravity environments, to produce clean water for reuse in these environments. The nutrients taken up by the sphagna will also be utilised as a growth medium for cultivar growth, such as those selected for hydroponics' systems.

McKeon, M.; Wheeler, R.; Leahy, Jj

460

Anion/calcium ion ratios and proton production in some mitochondrial calcium ion uptakes.  

PubMed Central

The uptake of Ca2+ by liver mitochondria, when phosphate movement is inhibited, occurs when Co2 is present and not in its absence. Uptake of Ca2+ to form CaCO3 yields 2H+/Ca2+. Heart mitochondria, when phosphate movement is inhibited, will take up Ca2+ with the exact equivalent of hydroxybutyrate, lactate or acetate. By providing a carrier for Cl- with tributyltin, a stoicheiometric uptake of Cl- with the Ca2+ takes place. The uptakes appear to occur without significant pH change; there appears to be no CO2-dependent uptake into heart mitochondria. Oxygenation of anaerobic heart mitochondria, in the presence of an inhibitor of phosphate movement and of generation of phosphate from internal ATP, does not yield significant change of external acidity in relation to the amount of O2 added. Use of Bromothymol Blue as an indicator of the distribution of a weak acid anion confirms that the transient nature of the response of the dye distribution to Ca2+ is connected with movement of endogenous phosphate. Bromothymol Blue accumulated in response to Ca2+ is discharged when entry of the Ca2+ (in the presence of mersalyl) is mediated with nigericin. It is concluded that Ca2+ uptakes will occur alternatively with the equivalent of anions or in exchange for endogenous K+ and that proton production is connected with the changes of ionization of phosphate (unless phosphate movement is inhibited) and in liver mitochondria with the hydration of CO2.

Harris, E J

1978-01-01

461

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

Microsoft Academic Search

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

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

2005-01-01

462

CHEMICAL ASPECTS OF THE USE OF SOLUBLE POISONS FOR REACTIVITY CONTROL IN CANDU. I. SOLUBLE POISON REMOVAL BY ION EXCHANGE  

Microsoft Academic Search

The removal of boric acid and cadmium sulfate from water by ion exchange ; resins down to concentrations of 0.01 ppm or less was studied. Because of the ; much smaller quantity of resin required for cadmium sulfate removal, it is ; recommended as the soluble poison to be used in CANDU. Ion exchange equilibrium ; constants were measured and

R. E. Hollies; H. K. Rae

1962-01-01

463

Commercial Ion Exchange Resin Vitrification in Borosilicate Glass  

SciTech Connect

Bench-scale studies were performed to determine the feasibility of vitrification treatment of six resins representative of those used in the commercial nuclear industry. Each resin was successfully immobilized using the same proprietary borosilicate glass formulation. Waste loadings varied from 38 to 70 g of resin/100 g of glass produced depending on the particular resin, with volume reductions of 28 percent to 68 percent. The bench-scale results were used to perform a melter demonstration with one of the resins at the Clemson Environmental Technologies Laboratory (CETL). The resin used was a weakly acidic meth acrylic cation exchange resin. The vitrification process utilized represented a approximately 64 percent volume reduction. Glass characterization, radionuclide retention, offgas analyses, and system compatibility results will be discussed in this paper.

Cicero-Herman, C.A.; Workman, P. [Westinghouse Savannah River Co., Aiken, SC (United States); Poole, K.; Erich, D.; Harden, J. [Clemson Environmental Technologies Laboratory, Anderson, SC (United States)

1998-05-01

464

Integrated separation scheme for coal-derived liquids using ion-exchange and adsorption chromatography  

Microsoft Academic Search

A separation scheme for coal-derived liquids has been developed that separates by functionality into discrete compound classes using ion-exchange resins; neutrals are further subdivided into fractions differing in polarity, structure, and molecular weight by adsorption chromatography. Sufficient material can be separated to allow further characterization at both gross structural and molecular levels. It gives excellent overall reproducibility (+\\/- 4%) and

Michael G. Strachan; R. B. Johns

1986-01-01

465

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

National Technical Information Service (NTIS)

In this research program, Oak Ridge National Laboratory (ORNL) is collaborating with Texas A and M University in the development of highly selective inorganic ion exchangers for the removal of cesium and strontium from nuclear tank-waste and from groundwa...

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

1997-01-01

466

Formulation, Characterization and Evaluation of Rapid Disintegrating Tablet of atifloxacin Sesquihydrate by ion exchange resin technique  

Microsoft Academic Search

Gatifloxacin Sesquihydrate is a Broad Spectrum Antimicrobial agent active against Gram Positive and Gram Negative Organism. It is slightly bitter in taste. In the present study an attempt has been made to prepare bitterless fast dissolving tablet of Gatifloxacin Sesquihydrate using Indion 204, Indion 214, Indion 234, Tulsion 335 (ion exchange resin) as a taste masking agent. X-ray powder diffractometry,

P. S. Gangane; K. G. Mahajan; H. S. Sawarkar; V. S. Adhao

467

Electrochemical Ion-Exchange for Medium Active Liquid Waste Treatment. Progress Report 1987.  

National Technical Information Service (NTIS)

A non-active 0.1 m/sup 3//h electrochemical ion-exchange (EIX) treatment plant has been successfully commissioned using 0.2 x 1 m electrodes fabricated from mixed Amberlite CG50/IRC84 by a mould route. At 50% design throughout, DFs of 20,000 were observed...

A. D. Turner N. J. Bridger A. R. Junkison

1988-01-01