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1

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

2

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

3

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

4

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

5

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

6

Cesium-specific phenolic ion exchange resin  

DOEpatents

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

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

1995-01-01

7

Vitrification of ion exchange resins  

DOEpatents

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

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

2001-01-01

8

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

9

Phosphonic acid based ion exchange resins  

DOEpatents

An ion exchange resin is described for extracting metal ions from a liquid waste stream. An ion exchange resin is prepared by copolymerizing a vinylidene diphosphonic acid with styrene, acrylonitrile and divinylbenzene. 9 figures.

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

1994-01-25

10

Phosphonic acid based ion exchange resins  

DOEpatents

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

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

1996-07-23

11

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

12

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

13

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

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

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

1998-01-27

14

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

15

Grafted methylenediphosphonate ion exchange resins  

DOEpatents

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

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

1997-01-01

16

Ion Exchange and Liquid Column Chromatography.  

ERIC Educational Resources Information Center

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

Walton, Harold F.

1980-01-01

17

Mass transfer and kinetics of ion exchange  

Microsoft Academic Search

These papers were written by leading scientists and technologists working in the field of ion exchange, and they discuss the synthesis, equilibria, transport phenomena, kinetics and design of ion exchange resins and membranes, both systematically and progressively. This volume also reflects recent developments in the field, with sections dealing with novel areas of application for ion exchange, such as, pollution

L. Liberti; F. L. Helfferich

1983-01-01

18

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

19

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

20

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. 2 figs.

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

1990-10-23

21

Ion-exchange properties of 4-vinylpyridine–divinylbenzene-based anion exchangers for ferric chloride complex anions  

Microsoft Academic Search

4-Vinylpyridine–divinylbenzene-based anion exchangers were synthesized by suspension polymerization. Diluent mixtures containing a range of cyclohexane to cyclohexanone ratio were employed to dilute monomers at the time of polymerization. The ion exchangers were characterized for porosity, ion exchange capacity and t1\\/2 for exchange of (FeCl4)? ions adsorbed on resins and those in the surrounding solution. A gradual increase of cyclohexane fraction

Muhammad Arif Malik; Rehana Mukhtar; S. A. R. Zaidi; Shafaat Ahmed; M. Afzal Awan

2002-01-01

22

Facility produced charge-exchange ions  

NASA Technical Reports Server (NTRS)

These facility produced ions are created by charge-exchange collisions between neutral atoms and energetic thruster beam ions. The result of the electron transfer is an energetic neutral atom and an ion of only thermal energy. There are true charge-exchange ions produced by collisions with neutrals escaping from the ion thruster and being charge-exchange ionized before the neutral intercepts the tank wall. The facility produced charge-exchange ions will not exist in space and therefore, represent a source of error where measurements involving ion thruster plasmas and their density are involved. The quantity of facility produced ions in a test chamber with a 30 cm mercury ion thruster was determined.

Carruth, M. R., Jr.

1981-01-01

23

Using Ion Exchange Chromatography to Separate and Quantify Complex Ions  

ERIC Educational Resources Information Center

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

Johnson, Brian J.

2014-01-01

24

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

PubMed

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

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

2014-07-15

25

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

26

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

27

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...

28

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

29

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

30

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.

Ellyn A. Daugherty

31

Ion Exchange in Nonaqueous and Mixed Media  

Microsoft Academic Search

Enough experimental data on nonaqueous ion-exchange separations have been gathered to show that one is dealing with a field whose theoretical aspects are infinitely complicated. The separations can be based on several different types of chemical reactions. Apart from true ion exchange, sorption can take place by non-exchange reactions such as acid-base reactions or complex-formation, either by hydrogen bonding or

Walter R. Heumann; James S. Fritz

1971-01-01

32

21 CFR 173.21 - Perfluorinated ion exchange membranes.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 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...

2013-04-01

33

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...

2010-04-01

34

21 CFR 173.21 - Perfluorinated ion exchange membranes.  

Code of Federal Regulations, 2012 CFR

... 2012-04-01 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...

2012-04-01

35

21 CFR 173.21 - Perfluorinated ion exchange membranes.  

Code of Federal Regulations, 2011 CFR

... 2011-04-01 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...

2011-04-01

36

21 CFR 173.21 - Perfluorinated ion exchange membranes.  

Code of Federal Regulations, 2014 CFR

... 2014-04-01 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...

2014-04-01

37

Developments in ion exchange: The mintek perspective  

NASA Astrophysics Data System (ADS)

Mintek has been involved in the development of ion-exchange technologies for the gold industry for more than 25 years. These technologies include the development of gold-selective anionexchange resins, design and engineering aspects of resin-in-pulp and resin-in-solution for the recovery of gold, and the use of ion exchange for the recovery and recycling of cyanide. More recently, an automated ion-exchange process was developed to recover gold powder from carbon eluate in an attempt to limit gold theft during the final stages of processing.

Green, B. R.; Kotze, M. H.; Wyethe, J. P.

2002-10-01

38

Crystalline silicotitanates -- novel commercial cesium ion exchangers  

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. These CST properties made them excellent candidates for treatment of solutions such as the Hanford tank supernates and other DOE radwastes. Sandia and UOP, under a Cooperative Research and Development Agreement (CRADA), developed 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 Sandia and Texas A&M consists of submicron-size particles. It is not designed for column ion exchange but may be used in other applications such as batch waste processing. Data are also presented confirming the excellent stability of the commercial CSTs over a broad pH range and the high radiation stability of the exchangers. In addition, data are provided that demonstrate the high physical strength and attrition resistance of IONSIV{reg_sign} IE-911, critical properties for column ion exchange applications.

Braun, R.; Dangieri, T.J.; Fennelly, D.J. [UOP, Des Plaines, IL (United States)] [and others

1996-12-31

39

Polyatomic ions, branching ratios and hot molecules  

NASA Astrophysics Data System (ADS)

A discussion is given of the reason for the sharp fall-off observed in Dissociative Recombination (DR) cross sections above about 0.1 eV and of the need for accurate branching ratios being used in complex models of molecular ion chemistry. New measurements from TSR have shown that stored ions are not as cold as they were once thought to be and a new experiment facility is presented.

Mitchell, J. Brian A.

2015-01-01

40

Solvent Extraction and Ion Exchange in Radiochemistry  

NASA Astrophysics Data System (ADS)

In 1805, Bucholz extracted uranium from a nitric acid solution into ether and back-extracted it into pure water. This is probably the first reported solvent-extraction investigation. During the following decades, the distribution of neutral compounds between aqueous phases and pure solvents was studied, e.g., by Peligot, Berthelot and Jungfleisch, and Nernst. Selective extractants for analytical purposes became available during the first decades of the twentieth century. From about 1940, extractants such as organophosphorous esters and amines were developed for use in the nuclear fuel cycle. This connection between radiochemistry and solvent-extraction chemistry made radiochemists heavily involved in the development of new solvent extraction processes, and eventually solvent extraction became a major separation technique in radiochemistry. About 160 years ago, Thompson and Way observed that soil can remove potassium and ammonium ions from an aqueous solution and release calcium ions. This is probably the first scientific report on an ion-exchange separation. The first synthesis of the type of organic ion exchangers that are used today was performed by Adams and Holmes in 1935. Since then, ion-exchange techniques have been used extensively for separations of various radionuclides in trace as well as macro amounts. During the last 4 decades, inorganic ion exchangers have also found a variety of applications. Today, solvent extraction as well as ion exchange are used extensively in the nuclear industry and for nuclear, chemical, and medical research. Some of these applications are discussed in the chapter.

Skarnemark, G.

41

ION EXCHANGE SOFTENING: EFFECTS ON METAL CONCENTRATIONS  

EPA Science Inventory

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

42

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

2008-12-15

43

Modeling of Crystalline Silicotitanate Ion Exchange Columns  

SciTech Connect

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

Walker, D.D.

1999-03-09

44

Graphene/Ionic Liquid Composite Films and Ion Exchange  

PubMed Central

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

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

2014-01-01

45

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

46

REMOVING RADIUM-226 ION EXCHANGE RESINS  

E-print Network

Water Sanitary Sewer System Radium Compliant Water Waterways or On-site WW Disposal System Landfill period of time 11 Objective 1 - Resin Exhaustion Study Site Location & Layout Water Treatment Building alternate well site 5 Radium-226 Treatment Using Ion Exchange Resin · Raw water flows through treatment unit

47

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

48

Liquid membrane coated ion-exchange column solids  

DOEpatents

This invention relates to a method for improving the performance of liquid embrane separations by coating a liquid membrane onto solid ion-exchange resin beads in a fixed bed. Ion-exchange beads fabricated from an ion-exchange resin are swelled with water and are coated with a liquid membrane material that forms a film over the beads. The beads constitute a fixed bed ion-exchange column. Fluid being treated that contains the desired ion to be trapped by the ion-exchange particle is passed through the column. A carrier molecule, contained in the liquid membrane ion-exchange material, is selected for the desired ion in the fluid. The carrier molecule forms a complex with the desired ion, transporting it through the membrane and thus separating it from the other ions. The solution is fed continuously until breakthrough occurs at which time the ion is recovered, and the bed is regenerated.

Barkey, Dale P. (Berkeley, CA)

1989-01-01

49

Liquid membrane coated ion-exchange column solids  

DOEpatents

This invention relates to a method for improving the performance of liquid membrane separations by coating a liquid membrane onto solid ion-exchange resin beads in a fixed bed. Ion-exchange beads fabricated from an ion-exchange resin are swelled with water and are coated with a liquid membrane material that forms a film over the beads. The beads constitute a fixed bed ion-exchange column. Fluid being treated that contains the desired ion to be trapped by the ion-exchange particle is passed through the column. A carrier molecule, contained in the liquid membrane ion-exchange material, is selective for the desired ion in the fluid. The carrier molecule forms a complex with the desired ion, transporting it through the membrane and thus separating it from the other ions. The solution is fed continuously until breakthrough occurs at which time the ion is recovered, and the bed is regenerated.

Barkey, Dale P. (Berkeley, CA)

1988-01-01

50

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

PubMed Central

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

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

2012-01-01

51

Rapid exchange effects on isotope ratios in groundwater systems: 2. Flow investigation using Sr isotope ratios  

NASA Astrophysics Data System (ADS)

Sr isotope ratios were measured in groundwater, whole rock digestions, and cation exchange extracts from a clay-rich groundwater system at Ernest O. Lawrence Berkeley National Laboratory and were used to constrain flow velocities and search for preferential flow paths. In the Orinda formation siltstone, 87Sr/86Sr increases strongly over tens of meters along presumed flow paths, indicating slow groundwater flow. Dissolved Sr is close to isotopic equilibrium with the exchangeable Sr in the clays, and the observed 87Sr/86Sr increase is interpreted as a cation exchange front moving slowly through the unit combined with dissolution of minerals with relatively high 87Sr/86Sr ratios. The data are inverted using a one-dimensional transport-dissolution-exchange model; the results indicate long-term average flow velocities of less than 0.2 m/yr which are consistent with 14C measurements. The data suggest a lack of strong preferential flow paths through this unit.

Johnson, Thomas M.; Depaolo, Donald J.

1997-01-01

52

Porous solid ion exchange wafer for immobilizing biomolecules  

SciTech Connect

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

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

2007-12-11

53

Ferrous-Ferric Ion exchange dosemeter.  

PubMed

In this work a three-dimensional ferrous-ferric ion exchange dosemeter is proposed and the dose response measured. The dosemeter consists of strong acid cation exchange resin beads in the H form in water. Amberlyst 15 Wet beads with a harmonic mean diameter of 0.600-0.850 mm were prepared by soaking them in an aqueous solution of ferrous ammonium sulphate to exchange ferrous ions for H(+) ions. The beads were rinsed with distilled water and packed in glass vials. Sets of samples with ferrous ion concentrations of 0.5 and 1.0 mM were dosed with 6 MV X rays from a Varian 2100C linac. The spin-lattice relaxation time constants (T1) for the samples were measured using an Apollo spectrometer (Tecmag, Houston, TX) interfaced to a 1.5 T magnet (Magnex, Abingdon, UK). Each sample had two T1 values; a long T1 at 1200 ms that did not significantly change with dose and a short T1 that ranged from 56 ms at 0 Gy to 36 ms at 100 Gy. The R1 vs. dose responses were linear with slopes of 0.066 and 0.079 s(-1) Gy(-1). PMID:16644977

Bauhs, John A; Hammer, Bruce E

2006-01-01

54

21 CFR 173.20 - Ion-exchange membranes.  

Code of Federal Regulations, 2011 CFR

...Drugs 3 2011-04-01 2011-04-01 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...

2011-04-01

55

21 CFR 173.20 - Ion-exchange membranes.  

Code of Federal Regulations, 2014 CFR

...Drugs 3 2014-04-01 2014-04-01 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...

2014-04-01

56

21 CFR 173.20 - Ion-exchange membranes.  

Code of Federal Regulations, 2013 CFR

...Drugs 3 2013-04-01 2013-04-01 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...

2013-04-01

57

21 CFR 173.20 - Ion-exchange membranes.  

Code of Federal Regulations, 2012 CFR

...Drugs 3 2012-04-01 2012-04-01 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...

2012-04-01

58

21 CFR 173.20 - Ion-exchange membranes.  

Code of Federal Regulations, 2010 CFR

...Drugs 3 2010-04-01 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...

2010-04-01

59

Sorption of radionuclides on cerium(IV) molybdophosphate ion exchanger  

Microsoft Academic Search

Samples of a new inorganic ion exchanger cerium(IV) molybdophosphate have been prepared under varying conditions. Ion exchange\\u000a capacity, I.R, thermogravimetry and sorption of radionuclides have been studied. Separations of Sr?Rb and Cd?Ag have been\\u000a developed on column of this ion exchanger.

M. G. Marageh; S. Waqif-Husain; A. R. Khanchi

1999-01-01

60

Charge exchange lifetimes for ions in the magnetosphere  

NASA Technical Reports Server (NTRS)

Latest and best measurements of physical quantities involved in complete calculation of the charge exchange lifetime of mirroring magnetospheric ions are coalesced and summarized. It is critical that the charge exchange lifetimes for ions be known as accurately as possible in order to apply the charge exchange mechanism to ion phenomena within the earth's magnetosphere.

Smith, P. H.; Bewtra, N. K.

1977-01-01

61

Processing-property relationship in ion-exchanged ESP (engineered stress profile) glasses  

NASA Astrophysics Data System (ADS)

A novel two-step ion exchange process was recently proposed to produce Engineered Stress Profile (ESP) glass. Important characteristics of ESP glass include high strength, relatively low strength variability and high surface damage resistance. It has been found that the mechanical reliability of ESP glass is mainly dependent on the processing conditions. Therefore, the primary objective of the current thesis is to quantitatively study the relationship between the mechanical properties of ESP glasses and the ion exchange processing conditions. Based on this relationship, processing conditions can be determined for any particular requirement of mechanical behavior for ion exchanged glass. To establish a property-processing relationship in ESP glasses, it is necessary to predict the stress profile in ion exchanged glass from the processing conditions. Since the residual stress profile in ion exchanged glass is mainly caused by the K/Na ion exchange and the stress relaxation, the diffusion process and the stress relaxation behavior of glass were studied. The K2O concentration profiles in singe-step and two-step ion exchanged soda lime silicate (SLS) glasses were calculated and found to be in a good agreement with the measured concentration profiles. The uniaxial compressive stress relaxation behavior of the SLS glass in the current thesis at typical ion exchange temperatures was studied. Since the surface composition in ion exchanged glass is significantly different from the composition of untreated glass, this composition difference could cause significant difference in glass properties including viscosity and stress relaxation. Therefore, properties of glasses with different K/Na ratios were studied, and empirical equations were obtained to estimate glass properties from the glass composition. Given the diffusion coefficient, surface concentration, composition-dependent dilation coefficient and stress relaxation data, residual stress profiles in ion-exchanged glasses could be calculated. These calculated stress profiles in single-step and two-step ion exchanged glasses have a reasonable agreement with the measured stress profiles using an optimized optical method. In addition, a variable temperature ion exchange process was used to produce ESP glass with a lower production cost than that for two-step ion exchange process. However, similar mechanical properties can be achieved by a variable temperature ion exchange process. Strength and strength variability of ion-exchanged glasses were predicted from the measured stress profile. Overall, an experimental methodology for predicting stress profiles in ion exchanged glasses is described. This methodology involves measuring the diffusion coefficient, stress relaxation behavior of SLS glass and other mixed alkali silicate glasses, calculating the stress profile in ion exchanged glass from the measured diffusivity data and stress relaxation data, and then comparing the calculated and experimentally measured stress profiles in glass.

Shen, Junwu

2003-06-01

62

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

63

Features of ion transport in perfluorinated ion-exchange membranes  

SciTech Connect

The conditions for functioning for various systems and devices electrolyzers for ''chlorate'' electrolysis, current sources, etc.) with perfluorinated ion-exchange membranes and septums are determined to a considerable degree by the physicochemical properties of the perfluorinated materials. In this work, on the basis of concepts developed in streaming theory as to the topology of the ''infinite clusters'' (ICs), the author defines more precisely the form of the preexponential dependence of ion transport coefficients and draws conclusions on the character of heat evolution in a perfluorinated membrane when an electric current is passed through the membrane.

Timashev, S.F.

1986-02-01

64

Ion exchange properties of humus acids  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

65

Ion exchange in hydroxyapatite with lanthanides.  

PubMed

Naturally occurring hydroxyapatite, Ca5(PO4)3(OH) (HAP), is the main inorganic component of bone matrix, with synthetic analogues finding applications in bioceramics and catalysis. An interesting and valuable property of both natural and synthetic HAP is the ability to undergo cationic and anionic substitution. The lanthanides are well-suited for substitution for the Ca(2+) sites within HAP, because of their similarities in ionic radii, donor atom requirements, and coordination geometries. We have used isothermal titration calorimetry (ITC) to investigate the thermodynamics of ion exchange in HAP with a representative series of lanthanide ions, La(3+), Sm(3+), Gd(3+), Ho(3+), Yb(3+) and Lu(3+), reporting the association constant (Ka), ion-exchange thermodynamic parameters (?H, ?S, ?G), and binding stoichiometry (n). We also probe the nature of the La(3+):HAP interaction by solid-state nuclear magnetic resonance ((31)P NMR), X-ray diffraction (XRD), and inductively coupled plasma-optical emission spectroscopy (ICP-OES), in support of the ITC results. PMID:25594577

Cawthray, Jacqueline F; Creagh, A Louise; Haynes, Charles A; Orvig, Chris

2015-02-16

66

High pressure ratio cryocooler with integral expander and heat exchanger  

NASA Astrophysics Data System (ADS)

A new 1 W, 4.2 K cryocooler is under development that is intended to miniaturize helium temperature refrigeration systems using a high-pressure-ratio Collins-type cycle. The configuration resulted from optimization studies of a saturated vapor compression (SCV) cycle that employs miniature parallel-plate heat exchangers. The basic configuration is a long displacer in a close-fitting, thin-walled cylinder. The displacer-to-cylinder gap is the high-pressure passage of the heat exchanger, and the low-pressure passage is formed by a thin tube over the OD of the cylinder. A solenoid-operated inlet valve admits 40 atm helium to the displacer-to-cylinder gap at room temperature, while the solenoid-operated exhaust valve operates at 4 atm. The single-stage cryocooler produces 1 W of refrigeration at 40 K without precooling and at 20 K with liquid nitrogen precooling.

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

67

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

68

Ion exchange of ammonium in natural and synthesized zeolites.  

PubMed

In this study, zeolite Na-P and Na-Y was prepared by hydrothermal treatment of the Chinese natural clinoptilolite with NaOH. The ion exchange of NH4+ into the three zeolites in the temperature range of 288-333K was also investigated, and the thermodynamic parameters were calculated. The selectivity sequence for NH4+ entering the sodium form of the three materials was Na-clinoptilolite>Na-Y>Na-P, as indicated by values of DeltaG degrees . The results demonstrated that the Si/Al molar ratio of zeolites determined the selectivity for NH4+. PMID:18417280

Wang, Yifei; Lin, Feng; Pang, Wenqin

2008-12-30

69

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

70

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

71

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

72

FOCUS: ION THERMOCHEMISTRY Temperature-Dependent H/D Exchange  

E-print Network

exchange levels for rapidly exchanging sites increase with temperature. At 300 K, exchange levels of 53 3 factors such as solu- tion composition, pH, and temperature. However, the degree to which environmentFOCUS: ION THERMOCHEMISTRY Temperature-Dependent H/D Exchange of Compact and Elongated Cytochrome c

Clemmer, David E.

73

Ion exchange capacity of Nafion and Nafion composites  

Microsoft Academic Search

The ion exchange capacity of recast Nafion films and composites of Nafion and polystyrene microbeads is determined by titration. Composite formation enhances exchange capacity; exchange capacity increases with the surface area microbeads in the composite. For recast films, an equivalent weight of 996 {+-} 24 is found, whereas the lowest equivalent weight (highest exchange capacity) found for composite is 878

Ta-Yung Chen; Johna Leddy

2000-01-01

74

Ion-Exchangeable, Electronically Conducting Layered Perovskite Oxyfluorides  

E-print Network

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

75

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

76

Ion exchange chromatography of antibody fragments.  

PubMed

Effects of pH and conductivity on the ion exchange chromatographic purification of an antigen-binding antibody fragment (Fab) of pI 8.0 were investigated. Normal sulfopropyl (SP) group modified agarose particles (SP Sepharosetrade mark Fast Flow) and dextran modified particles (SP Sepharose XL) were studied. Chromatographic measurements including adsorption isotherms and dynamic breakthrough binding capacities, were complemented with laser scanning confocal microscopy. As expected static equilibrium and dynamic binding capacities were generally reduced by increasing mobile phase conductivity (1-25 mS/cm). However at pH 4 on SP Sepharose XL, Fab dynamic binding capacity increased from 130 to 160 (mg/mL media) as mobile phase conductivity changed from 1 to 5 mS/cm. Decreasing protein net charge by increasing pH from 4 to 5 at 1.3 mS/cm caused dynamic binding capacity to increase from 130 to 180 mg/mL. Confocal scanning laser microscopy studies indicate such increases were due to faster intra-particle mass transport and hence greater utilization of the media's available binding capacity. Such results are in agreement with recent studies related to ion exchange of whole antibody molecules under similar conditions. PMID:17096387

Ljunglöf, Anders; Lacki, Karol M; Mueller, Jay; Harinarayan, Chithkala; van Reis, Robert; Fahrner, Robert; Van Alstine, James M

2007-02-15

77

Mineral Separation in a CELSS by Ion-exchange Chromatography  

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

78

Ion exchange of cesium by crystalline silico-titanates  

SciTech Connect

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

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

1995-12-01

79

Zeolitic ammonium ion exchange for portable hemodialysis dialysate regeneration.  

PubMed

Ammonia removal from a recirculating dialysate stream is a major challenge in developing a truly portable, regenerable hemodialysis system. Three zeolites, type F, type W, and clinoptilolite, were found to have good ammonia ion exchange capacity with linear equilibrium ion exchange coefficients of 0.908, 0.488, and 0.075 L/g, respectively. The linear equilibrium ion exchange coefficient relates dialysate ammonia concentration (mumol/L) to the amount of ammonia absorbed by zeolite (mumol/g) at equilibrium. Ammonia uptake by zeolite powders was fast, with equilibrium reached within 15 sec. Zeolite ammonia ion exchange and regeneration through multiple cycles was studied using an ion exchange column containing clinoptilolite pellets. Zeolite ion exchange capability was regenerated by flushing the column with 2 mol/L sodium chloride after an ion exchange run. The column maintained ammonia ion exchange capacity through six ion exchange/regeneration cycles, demonstrating multiple dialysis use possibilities. Atomic absorption spectroscopy of the column effluent showed no detectible (< 1 part per million) Si or Al leached from the zeolite. PMID:7640432

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

1995-01-01

80

Effects of ionizing radiation on modern ion exchange materials  

SciTech Connect

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

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

1993-10-01

81

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

SciTech Connect

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

RAMSEY AA; THORSON MR

2010-12-28

82

Pyrolysis of Spent Ion Exchange Resins - 12210  

SciTech Connect

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

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

2012-07-01

83

Waste treatment by selective mineral ion exchanger  

SciTech Connect

STMI, subsidiary company of the AREVA Group with over 40 years in the D and D business, has been continuously innovating and developing new decontamination techniques, with the objectives of achieving more efficient decontaminations on a growing spectrum of media. In the field of liquid waste treatment, STMI manufactures uses and commercialises selective inorganic ion exchangers (RAN). These are hydrated synthetic inorganic compounds prepared from very pure raw materials. Different types of RANs (POLYAN, OXTAIN, Fe-Cu, Fe-CoK, Si-Fe-CoK) can be used to trap a large number of radioactive elements in contaminated effluents. Different implementations could be applied depending on technical conditions. STMI's offers consist in building global solution and preliminary design of installation either in dispersed form (batch) or in column (cartridge filtration). Those products are used all over the world not only in the nuclear business (Canada, US, Belgium, France...) but also in other fields. Indeed, it provides competitive solutions to many domains of application especially water pollution control, liquid waste treatment in the nuclear business by decreasing the activity level of waste. The following paper will focus on the theoretical principle of the mineral exchanger, its implementation and the feed back collected by STMI. (author)

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

2007-07-01

84

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

SciTech Connect

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

Ham, J.E.

1996-01-04

85

Very thin barium ferrite particles prepared by a novel technique: Ion exchange resin method  

NASA Astrophysics Data System (ADS)

Very thin hexagonal barium ferrite particles have been prepared by a new method—ion exchange resin method. The exchanged resin when heated to 850 °C, transformed to the hexagonal ferrite BaFe12O19 as confirmed by x-ray diffraction. These particles show single-domain behavior with average diameter D¯=220 nm, average aspect ratio D¯/t¯=13, specific magnetization ?=71 emu/g and coercivity Hc=3800 Oe.

Zhong, Wei; Ding, Weiping; Jiang, Yumei; Wang, Liang; Zhang, Ning; Zhang, Shiyuan; Du, Youwei; Yan, Qijie

1999-04-01

86

Very thin barium ferrite particles prepared by a novel technique: Ion exchange resin method  

Microsoft Academic Search

Very thin hexagonal barium ferrite particles have been prepared by a new method-ion exchange resin method. The exchanged resin when heated to 850 °C, transformed to the hexagonal ferrite BaFe12O19 as confirmed by x-ray diffraction. These particles show single-domain behavior with average diameter D=220 nm, average aspect ratio D\\/t=13, specific magnetization sigma=71 emu\\/g and coercivity Hc=3800 Oe.

Wei Zhong; Weiping Ding; Yumei Jiang; Liang Wang; Ning Zhang; Shiyuan Zhang; Youwei Du; Qijie Yan

1999-01-01

87

The use of fibrous ion exchangers in gold hydrometallurgy  

NASA Astrophysics Data System (ADS)

This article examines a family of ion-exchange fibers, FIBAN, containing primary and secondary amine groups. These ion exchangers have a fiber diameter of 20 40 ?m, high osmotic and mechanic stability, a high rate of adsorption and regeneration, and excellent dynamic characteristics as filtering media. Inparticular, this article discusses the use of FIBAN fibrous ion exchangers in the recovery of gold cyanide andbase-metal cyanides (copper and mercury) from mineral-leaching solutions. The influence of polymer structure and water content on their extraction ability is described, along with key parameters of gold hydrometallurgy such as extraction efficiency, selectivity, pH dependence, gold cyanide loading, kinetics, and stripping.

Kautzmann, R. M.; Sampaio, C. H.; Cortina, J. L.; Soldatov, V.; Shunkevich, A.

2002-10-01

88

Interpenetrating polymer network ion exchange membranes and method for preparing same  

DOEpatents

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

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

1989-01-01

89

Ion Exchange Separation of the Oxidation State of Vanadium.  

ERIC Educational Resources Information Center

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

Cornelius, Richard

1980-01-01

90

WASTEWATER DEMINERALIZATION BY CONTINUOUS COUNTER-CURRENT ION EXCHANGE PROCESS  

EPA Science Inventory

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

91

Radiation effects on a zeolite ion exchanger and a pollucite  

Microsoft Academic Search

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

S. Komarneni; G. L. Palau; K. K. S. Pillay

1983-01-01

92

Topotaxial replacement of chlorapatite by hydroxyapatite during hydrothermal ion exchange  

Microsoft Academic Search

Exchange of Cl - by OH - in synthesized chlorapatite single crystals was investigated under hydro- thermal conditions. Hydrothermal treatments were performed at various temperatures from 200 to 500 °C, for intervals between 3 and 96 h in KOH or NaOH solutions. Ion exchange of Cl - in the chlorapatite crystals was completed at low temperature (500 °C) for a

K. YANAGISAWA; J. C. RENDON-ANGELES; N. ISHIZAWA; S. OISHI

1999-01-01

93

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

94

Ion exchange enrichment of uranium isotopes  

Microsoft Academic Search

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

T. Miyake; H. Onitsuka; K. Takeda

1983-01-01

95

Synthesis and Characterization of Novel Materials, Tin Potassium Vanadate and Zirconium Potassium Vanadate Inorganic MultiComponent Ion Exchangers  

Microsoft Academic Search

Nano polyoxometallate-cation exchangers, tin potassium vanadate (TPV), and zirconium potassium vanadate (ZPV), with stereoregular particulate structures have been chemically synthesized using a homogeneous precipitation technique under a variety of conditions. The experimental parameters such as mixing, volume ratio, order of mixing and pH were established for the synthesis of the materials and fairly compromised to optimize the ion exchange properties

G. M. Ibrahim; B. El-Gammal; I. M. El-Naggar

2011-01-01

96

Kinetics and dynamics of ion-exchange sorption-desorption of oxytetracycline using sulfonate cation exchanges of various grain size  

Microsoft Academic Search

The wide use of ion-exchange methods for isolation and purification of various substances is attracting ever-increasing attention from investigators in the field of study of the kinetics of ion-exchange. This is connected with difficulties arising in the use of ion-exchange methods, consisting in the low accessibility of ionogenic groups [1-3], and also with the low rate of ion-exchange absorption, which

G. V. Samsonov; N. N. Momot

1972-01-01

97

Ion Exchange in Countercurrent Electrolysis in a Porous Membrane  

Microsoft Academic Search

In many sepration processes for electrolytes the economy of the process could be improved if ion exchange could be carried out simultaneously with the separation without additional stages; i.e., when, for instance, separating potassium chloride from a mixture of sodium and potassium chlorides, the anion could be replaced by the hydroxyl ion, thus producing, instead of potassium chloride, more valuable

Kyosti Kontturi; Hannu Revitzer

1989-01-01

98

Molecularly Imprinted Ion-Exchange Resin for Fe  

Microsoft Academic Search

Ion exchange resins selective for the sequestration of Fe from aqueous solutions containing citrate were prepared by the molecular imprinting technique. Sorption characteristics of imprinted resins prepared with high (85 mole%) and low (3 mole%) amounts of covalent cross?linking were examined. Experiments to determine loading capacity and selectivity, relative to several metal ions of physiological significance, were performed. The Fe capacity of

George S. Owens; Glen E. Southard; Kelly A. Van Houten; George M. Murray

2005-01-01

99

Ion momentum and energy transfer rates for charge exchange collisions  

NASA Technical Reports Server (NTRS)

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

Horwitz, J.; Banks, P. M.

1973-01-01

100

A zeolite ion exchange membrane for redox flow batteries.  

PubMed

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

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

2014-03-01

101

Closed cycle ion exchange method for regenerating acids, bases, and salts  

Microsoft Academic Search

A method is described for conducting a chemical reaction in acidic, basic, or neutral solution as required and then regenerating the acid, base, or salt by means of ion exchange in a closed cycle reaction sequence which comprises contacting the spent acid, base, or salt with an ion exchanger. The ion exchanger is preferably a synthetic organic ion-exchange resin so

Dreyfuss

1976-01-01

102

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 around 3 mequiv g{sup -1}. The cation-exchange material, an amorphous aluminosilicate permutite-like material, (Na{sub x}+2yAl{sub x}Si{sub 1}-xO{sub 2+y}), has an IEC of around to 2.5 mequiv g{sup -1}. These ion-exchange materials were studied and optimized because of their specific ion-exchange capacity for the ions of interest and their ability to function in the temperature and pH regions necessary for cost and energy effectiveness. Room temperature, minimum pressure column studies (once-pass through) on simulant brackish water (total dissolved solids (TDS) = 2222 ppm) resulted in water containing TDS = 25 ppm. A second once-pass through column study on actual produced water (TDS = similar to 11 000) with a high carbonate concentration used an additional lime softening step and resulted in a decreased TDS of 600 ppm.

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

2006-06-21

103

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

104

Radiation effects on a zeolite ion exchanger and a pollucite  

SciTech Connect

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

Komarneni, S.; Palau, G.L.; Pillay, K.K.S.

1983-01-01

105

Ion exchange in glass using femtosecond laser irradiation  

SciTech Connect

We explain the occurrence of ion exchange and an index profile around the focal point inside a commercial crown glass formed by femtosecond laser irradiation. The index profile in the photoinduced area has a ring-shaped pattern, which indicates that local densification occurred in the glass. An irregular surface reflecting the density distribution is formed around the focal point by dry etching process using a focused ion beam. By the irradiation of femtosecond laser pulses, the effect of ion exchange between the focal point and the surrounding area is also observed in the area in which local densification occurred.

Kanehira, Shingo [Innovative Collaboration Center, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan); Miura, Kiyotaka; Hirao, Kazuyuki [Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan)

2008-07-14

106

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

PubMed

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

Rajabi, Khadijeh

2015-02-01

107

ION EXCHANGE PERFORMANCE OF TITANOSILICATES, GERMANATES AND CARBON NANOTUBES  

SciTech Connect

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

Alsobrook, A.; Hobbs, D.

2013-04-24

108

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

SciTech Connect

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

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

1999-01-01

109

Ion-exchanger synthesis using reversible addition-fragmentation chain transfer polymerization.  

PubMed

An ion-exchanger with polyanionic molecular brushes was synthesized by a "grafting from" route based on "surface-controlled reversible addition-fragmentation chain transfer polymerization" (RAFT). The RAFT agent, PhC(S)SMgBr was covalently attached to monodisperse-porous poly(dihydroxypropyl methacrylate-co-ethylene dimethacrylate), poly(DHPM-co-EDM) particles 5.8 microm in size. The monomer, 3-sulfopropyl methacrylate (SPM), was grafted from the surface of poly(DHPM-co-EDM) particles with an immobilized chain transfer agent by the proposed RAFT protocol. The degree of polymerization of SPM (i. e. the molecular length of the polyanionic ligand) on the particles was controlled by varying the molar ratio of monomer/RAFT agent. The particles carrying polyanionic molecular brushes with different lengths were tested as packing material in the separation of proteins by ion exchange chromatography. The columns packed with the particles carrying relatively longer polyanionic ligands exhibited higher separation efficiency in the separation of four proteins. Plate heights between 130-200 microm were obtained. The ion-exchanger having poly-(SPM) ligand with lower degree of polymerization provided better peak-resolutions on applying a salt gradient with higher slope. The molecular length and the ion-exchanger group content of polyionic ligand were adjusted by controlling the degree of polymerization and the grafting density, respectively. This property allowed control of the separation performance of the ion-exchanger packing. PMID:19479766

Unsal, Ender; Uguzdogan, Erdal; Patir, Süleyman; Tuncel, Ali

2009-06-01

110

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

111

Ion exchangers as adsorbents for removing metals from aquatic media.  

PubMed

A polyaniline-based composite cation-exchange material was synthesized by way of sol-gel method and studied to explore its analytical and environmental applications. It was characterized by using instrumental analyses [Fourier transform infrared (spectrometer), X-ray, thermogravimetric analysis/differential thermal analysis, standard electron microscopy, and transmission electron microscopy]. Physicochemical studies, such as ion-exchange capacity, pH titrations, and chemical stability, along with effect of eluent concentration and elution, were also performed to exploit the ion-exchange capabilities. pH titration studies showed that the material presents monofunctional strong cation-exchange behavior. This nanocomposite material is semicrystalline in nature and exhibits improved thermal and chemical stability. The partition coefficient studies of different metal ions in the material were performed in demineralised water and different surfactant media, and it was found to be selective for Pb(II) and Hg(II) ions. To exploit the usefulness of the material as an adsorbent, some important quantitative binary separations of metal ions were performed on polyaniline Zr(IV) molybdophosphate columns. This composite cation exchanger can be applied for the treatment of polluted water to remove heavy metals. PMID:24292693

Khan, Meraj A; Bushra, Rani; Ahmad, Anees; Nabi, Syed A; Khan, Dilwar A; Akhtar, Arshia

2014-02-01

112

Properties of a Novel Ion-Exchange Film  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

113

Hydrous oxide ion-exchange compound catalysts  

DOEpatents

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

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

1990-01-01

114

THERMODYNAMICS OF ION-EXCHANGED NATURAL CLINOPTILOLITE  

EPA Science Inventory

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

115

Ion exchange polymers for anion separations  

DOEpatents

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

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

1997-01-01

116

Ion exchange polymers for anion separations  

DOEpatents

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

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

1997-09-23

117

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

118

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

119

Charge-exchange plasma generated by an ion thruster  

NASA Technical Reports Server (NTRS)

The charge exchange plasma generated by an ion thruster was investigated experimentally using both 5 cm and 15 cm thrusters. Results are shown for wide ranges of radial distance from the thruster and angle from the beam direction. Considerations of test environment, as well as distance from the thruster, indicate that a valid simulation of a thruster on a spacecraft was obtained. A calculation procedure and a sample calculation of charge exchange plasma density and saturation electron current density are included.

Kaufman, H. R.

1977-01-01

120

A study of silver-film ion-exchanged glass waveguides in phosphate glass  

NASA Astrophysics Data System (ADS)

In this work, properties of Ag thin-film ion exchange in Schott IOG-1 phosphate glass has been studied. Emphasis has been put on finding the proper diffusion parameters (self-diffusion coefficient for Ag + ions and the mobility ratio between the participating ions) at process temperatures of 90°C and 230°C. In order to extract the diffusion parameters a following procedure was utilized: An ion-exchanged slab waveguide was fabricated using the same process conditions as in the case of a two-dimensional waveguide fabrication. After slab waveguide fabrication, the effective refractive indices of the propagating modes were measured by prism coupling. Thereafter, a smooth refractive index profile was constructed by improved inverse Wentzel-Kramers-Brillouin method. This refractive index profile was compared with the Ag + ion concentration profile calculated from the diffusion equation by Crank-Nicolson method. The self-diffusion coefficient for Ag + ions and the ratio of the self-diffusion coefficients of Ag + and Na + ions were varied until convergence between the refractive index profile and the concentration profile was found. Using the diffusion parameters obtained from these experiments, two-dimensional waveguide mode profiles were calculated by finite difference method. These theoretically obtained mode profiles were compared with the measured mode profiles with different mask opening widths.

Yliniemi, Sanna; Albert, Jacques; Honkanen, Seppo

2007-02-01

121

Polyamines and Pectins (I. Ion Exchange and Selectivity).  

PubMed Central

The ion-binding and -exchange properties of putrescine, spermidine, and spermine on purified walls of carrot (Daucus carota L.) cell suspensions were investigated by producing ion-exchange isotherms and comparing them with the behavior of Na+, Mg2+, and Ca2+. The cation exchange capacity of the carrot cell walls was 0.8 equivalent kg-1 dry matter, and the ionic selectivity sequence of the walls for polyamines followed the sequence spermine4+ > spermidine3+ [almost equal to] Ca2+ > putrescine2+. The polyamines were subjected to only electroselectivity and probably did not induce any favorable supramolecular conformation of pectin like the one induced by Ca2+. Triangular ion exchanges were also performed with three diamines: ethanediamine, butanediamine, and octanediamine. The shorter the diamine, the higher the total adsorption and selectivity of the exchange. The lower selectivity of the cell wall for putrescine was partly attributed to its inability to access and displace Ca2+ from higher affinity sites within dimerized pectic sequences. The polyamine adsorption and exchange on pectic sequences could result in pectic signal modulation in pathogenesis and in differentiation. PMID:12223613

Messiaen, J.; Cambier, P.; Van Cutsem, P.

1997-01-01

122

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

123

Multicomponent ion-exchange equilibria in chabazite zeolite  

Microsoft Academic Search

Efficient design ion-exchange columns, using Ionsiv IE-96 chabazite zeolite, for the decontamination of process wastewater that contains ppB levels of Sr-90 and Cs-137 requires a detailed study of binary and multicomponent ion-exchange equilibria. Experimental isotherms were acquired for Ca--Na, Mg--Na, Sr--Na, Cs--Na, Sr--Cs--Na, Ca--Mg--Na, Sr--Ca--Mg--Na, Cs--Ca--Mg--Na, and Sr--Cs--Ca--Mg--Na comparing batch and column experimental approaches. Binary isotherms obtained by the batch

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

1990-01-01

124

Ion-exchanged Tm3+:glass channel waveguide laser.  

PubMed

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

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

2013-04-01

125

Heavy ion beam probe systems for tight aspect ratio tokamaks  

SciTech Connect

We discuss the specific features of the application of heavy ion beam probe (HIBP) systems to tight aspect ratio tokamaks. We present and compare the HIBP projects for the TUMAN-3, GLOBUS, and COMPASS, where the inner part of the plasma is not available for regular chord diagnostics, so the HIBP becomes very desirable. All existing tight aspect ratio facilities and projects have a low (less than 1.9 T) toroidal field that requires a comparatively low beam energy range. The natural elongation and triangularity in tight aspect ratio tokamaks require an accurate calculation of the three-dimensional magnetic field for probing optimization. In comparison with traditional tokamaks, the detector grids have a wider energy interval. In general, the trajectories and detector grids for tight aspect ratio tokamaks become similar to the stellarator ones. Traditional and new probing schemes are suggested and discussed. {copyright} {ital 1997 American Institute of Physics.}

Melnikov, A.V.; Zimeleva, L.G. [Russian Research Centre Kurchatov Institute, Moscow (Russia)] [Russian Research Centre Kurchatov Institute, Moscow (Russia); Krupnik, L.I.; Nedzelskij, I.S.; Trofimenko, Y.V. [Ukrainian Research Centre KhIPT, Kharkov (Ukraine)] [Ukrainian Research Centre KhIPT, Kharkov (Ukraine); Minaev, V.B. [Saint-Petersburg Institute Physics and Technology, Saint-Petersburg (Russia)] [Saint-Petersburg Institute Physics and Technology, Saint-Petersburg (Russia)

1997-01-01

126

Ion exchange as a tertiary treatment  

E-print Network

. The aldehyde reacts with the amino groups. Secondary and tertiary amino groups are formed making the resin polyfunctional. The base strength and degree of crosslinking are proportional to the rela- tive amonnt of formaldehyde used. Those resins were capab... adjusted (3) . The most common strong base anion exchange resin is a polystyrene crosslinked by divinylbenzene. The basic groups are introduced into the resin structur e bv chloro? methylation of the polystyrene beads and subs equent treat? ment...

Westervelt, Ronald David

1968-01-01

127

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

128

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

129

Separation Report No. 100 Ion Exchange  

E-print Network

of Standard Proteins 3 2-3 Capacity 4 2-4 Effect of Sample Load 5 2-5 Dependence of Resolution on Flow Rate 6 pressure drops that result. Consequently, the use of smaller high efficiency particles is not common in ion and high resolution at a low column pressure drops equivalent to that of a conventional column. Table-1

Lebendiker, Mario

130

Quantitative determination of Mg in Al-alloys by ion-exchange TLC  

SciTech Connect

Analytical procedure for the quantitative determination of Mg in Al-alloys using ion-exchange thin layer chromatography is described. Chromatographic plates were coated with Amberlite IRP-69 (strong-acid cation exchanger in H[sup +]-form) mixed in different ratios with microcrystalline cellulose. Solutions of HCl and HNO[sub 3] respectively, in the concentration range from 0.5-2.0 mol dm[sup [minus]3] were used as developers. Chromatograms were visualized by spraying with ethanolic solution of 8-hydroxyquinoline and spots were scanned using Camag Turner Fluorometer 111. The optical separation was obtained on TLC plates containing 23% of ion-exchanger (particle size < 60 [mu]m) and by eluting with 1.25 M HCl. R[sub F] (Al) = 0.12, R[sub F](Mg) = 0.41.

Petrovic, M.; Kastelan-Macan, M. (Univ. of Zagreb (Croatia). Lab. for Analytical Chemistry); Turina, S.; Ivankovic, V. (Univ. of Zagreb (Croatia). Faculty of Mechanical Engineering and Naval Architecture)

1993-01-01

131

Insoluble polyelectrolyte and ion-exchange hollow fiber impregnated therewith  

NASA Technical Reports Server (NTRS)

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

Rembaum, A. (inventor)

1977-01-01

132

Modeling Uranium-Proton Ion Exchange in Biosorption  

E-print Network

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

Volesky, Bohumil

133

Closed cycle ion exchange method for regenerating acids, bases and salts  

Microsoft Academic Search

A method for conducting a chemical reaction in acidic, basic, or neutral solution as required and then regenerating the acid, base, or salt by means of ion exchange in a closed cycle reaction sequence which comprises contacting the spent acid, base, or salt with an ion exchanger, preferably a synthetic organic ion-exchange resin, so selected that the counter ions thereof

Dreyfuss; Robert M

1976-01-01

134

25th anniversary article: Ion exchange in colloidal nanocrystals.  

PubMed

We review the progress in ion exchange in a variety of nanocrystal structures from the earliest accounts dating back over two decades ago to the present day. In recent years the number of groups using this method to form otherwise difficult or inaccessible nanoparticle shapes and morphologies has increased considerably and the field has experienced a resurgence of interest. Whilst most of the early work on cation exchange centered on II-VI materials, the methodology has been expanded to cover a far broader range of semiconductor nanocrystals including low toxicity I-III-VI materials and the much less facile III-V materials. The extent of exchange can be controlled leading to lightly doped nanoparticles, alloys, core-shells, segmented rods and dots-in-rods. Progress has been driven by a better understanding of the underlying principles of the exchange process - from thermodynamic factors (differences in cation solubilities); the interactions between ions and transfer agents (solvents, ligands, anions, co-dopants); ionic in-diffusion mechanisms and kinetics. More recent availability of very detailed electron microscopy coupled with image reconstruction techniques has been a valuable tool to investigate the resulting heterostructures and internal interfaces. We start by surveying the range of synthetic approaches most often used to carry out ion exchange, mainly focusing on cation replacement strategies, and then describe the rich variety of nanostructures these techniques can bring forth. We also describe some of the principles that are used to establish the relative ease of exchange and to systematically improve the process where the basic energetics are less favorable. To help further the understanding of the underlying fundamentals we have gathered together useful data from the literature on solubilities, cation and anion hardness, ligand and solvent Lewis acid or base strengths for a wide range of chemical species generally used. We offer a perspective on the outlook for the field in terms of the emerging applications and the ion exchange derived materials that will enable them. PMID:24108549

Gupta, Shuchi; Kershaw, Stephen V; Rogach, Andrey L

2013-12-23

135

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.

136

Calculation of stopping power ratios for carbon ion dosimetry  

Microsoft Academic Search

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

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

2006-01-01

137

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

PubMed

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

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

2014-10-21

138

Improved reliability of leucite reinforced glass by ion exchange  

Microsoft Academic Search

Objectives: The aim of this study was to develop an adequate process-, proof- and calculation technique for the chemical strengthening of dental ceramic materials in order to evaluate the efficiency of this method from the engineering point of view.Methods: Ion exchange examinations below glass temperature have been done for the dental all ceramic system IPS-Empress (Ivoclar). In addition experiments on

H. Fischer; H. R. Maier; R. Marx

2000-01-01

139

Stabilization of Intrazeolitic Cadmium Telluride Nanoclusters by Ion Exchange  

E-print Network

Stabilization of Intrazeolitic Cadmium Telluride Nanoclusters by Ion Exchange Elaine S. Brigham telluride nanoclusters were prepared by vapor-phase deposition of elemental tellurium in Na+-zeolite A. The stability of the nanoclusters in environments that normally cause rapid Ostwald ripening or oxidation (air

140

DEVELOPMENT OF INORGANIC ION EXCHANGERS FOR NUCLEAR WASTE REMEDIATION  

EPA Science Inventory

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

141

Method and solvent composition for regenerating an ion exchange resin  

DOEpatents

A method and composition for removing perchlorate from a highly selective ion exchange resin is disclosed. The disclosed approach comprises treating the resin in a solution of super critical or liquid carbon dioxide and one or more quaternary ammonium chloride surfactant compounds.

Even, William R. (Livermore, CA); Irvin, David J. (Livermore, CA); Irvin, Jennifer A. (Livermore, CA); Tarver, Edward E. (Livermore, CA); Brown, Gilbert M. (Knoxville, TN); Wang, James C. F. (Livermore, CA)

2002-01-01

142

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

143

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, Si Y.; King, William D.

2012-12-20

144

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 ...

145

Separation of americium from curium by oxidation and ion exchange.  

PubMed

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

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

2012-08-21

146

Properties, ion-exchange behavior, and analytical applications of cerium phosphate cation exchangers suitable for column use  

SciTech Connect

Some investigations on the preparative procedure of cerium phosphate cation exchangers suitable for column use are reported. A number of novel forms of cerium phosphate compounds in the presence of different salts are synthesized. The properties of these inorganic ion exchangers have been characterized on the basis of chemical analysis, UV, thermal, IR and x-ray diffraction methods. Their ion-exchange properties, chemical stability, and selectivity for certain ions are investigated.

Nilchi, A.; Maragheh, M.G.; Khanchi, A.R. [Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of). Jaber Ibn Hayan Research Labs.] [Atomic Energy Organization of Iran, Tehran (Iran, Islamic Republic of). Jaber Ibn Hayan Research Labs.

1999-06-01

147

Ion Exchange Properties of the Canine Carotid Artery  

PubMed Central

Properties of the ion exchange mechanisms in the arterial wall were investigated by comparing water and electrolyte contents, and by measuring the steady-state entry of 22Na, 42K, and 26Cl under similar in vitro conditions. Overnight incubation of freshly dissected slices at 2°C resulted in an accumulation of sodium, chloride, and water and a loss of potassium. Subsequent incubation at 37°C in a physiological solution resulted in a reversal of these processes. Loss of water, sodium, and chloride at 37°C could also take place into a potassium-free solution. Under all conditions studied the quantity of fast exchanging electrolyte (half time less than 3 min) exceeded that contained in the inulin and sucrose spaces. The excess could not be attributed to connective tissue adsorption. A kinetic model was applied to the flux data which incorporated two simultaneous processes: bulk diffusion and a reversible reaction. The assumption that the cell membrane behaved as a discrete barrier for the exchange of all cell electrolyte was relaxed in this approach. A theory based upon the physicochemical properties of proteins, ions, and water in biological systems provided a physical basis for the kinetic model, and for interpreting the ion exchange properties of the vascular wall. PMID:5791547

Jones, A. W.; Karreman, G.

1969-01-01

148

Site of transition metal ions in ion-exchanged metal-doped glasses  

Microsoft Academic Search

Metal-for-alkali ion-exchange is largely used to dope surface layer of glass with metal ions so inducing a modification of the optical properties of the doped layer, useful to fabricate low-loss optical waveguides. X-ray absorption spectroscopy is a particularly important technique used to investigate the site of the metal ions introduced into the matrix, in specific cases also singling out the

C. Maurizio; F. D’Acapito; C. Sada; E. Cattaruzza; F. Gonella; G. Battaglin

2008-01-01

149

Ion exchange of zeolite membranes by a vacuum `flow-through' Seok-Jhin Kim a  

E-print Network

Ion exchange of zeolite membranes by a vacuum `flow-through' technique Seok-Jhin Kim October 2014 Keywords: Ion exchange Zeolite membrane Flow-through technique Separation Catalysis a b s t r a c t Ion exchange of nanoporous (e.g., zeolite) membranes is of increasing importance

Nair, Sankar

150

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

151

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

PubMed

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 degrees 56'N, 71 degrees 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. PMID:15318778

Wood, Warren W; Kraemer, Thomas F; Shapiro, Allen

2004-01-01

152

Exchange-coupled pairs of Fe 3+ ions in beryl  

NASA Astrophysics Data System (ADS)

The EPR spectrum of first nearest neighbour pairs of Fe 3+ ions substituting for Al 3+ ions in beryl is reported. The form of the pair spin Hamiltonian is discussed, and operator equivalent factors for fourth-order terms are tabulated. The Fe 3+ pair interionic coupling corresponds to isotropic antiferromagnetic exchange with J = + 1.7 cm-1 plus anisotropic dipolar coupling. The pair value of the zero-field splitting parameter D is + 0.0206 cm -1 and shows a substantial shift from the single-ion value. It is proposed that resonance lines previously attributed to Fe 3+ ions in Be 2+ or Si 4+ sites are due to Fe 3+ pairs.

Edgar, A.; Hutton, D. R.

1982-01-01

153

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

PubMed

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

Yuchi, Akio

2014-01-01

154

Multicomponent ion-exchange equilibria in chabazite zeolite  

SciTech Connect

Efficient design ion-exchange columns, using Ionsiv IE-96 chabazite zeolite, for the decontamination of process wastewater that contains ppB levels of Sr-90 and Cs-137 requires a detailed study of binary and multicomponent ion-exchange equilibria. Experimental isotherms were acquired for Ca--Na, Mg--Na, Sr--Na, Cs--Na, Sr--Cs--Na, Ca--Mg--Na, Sr--Ca--Mg--Na, Cs--Ca--Mg--Na, and Sr--Cs--Ca--Mg--Na comparing batch and column experimental approaches. Binary isotherms obtained by the batch technique were most successfully fitted with a modification of the Dubinin-Polyani equilibrium model. Prediction of the multicomponent equilibria from binary data will require more sophisticated modeling. 15 refs., 5 figs., 3 tabs.

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

1990-01-01

155

Metal ion exchange by natural and modified zeolites  

Microsoft Academic Search

The lead and cadmium removal from wastewaters by natural and pretreatment zeolites was examined by using a batch-type method. The results demonstrated that the natural zeolites contained a complement of exchangeable Na, K and Ca ions but exposing them to 2 M NaCl solution at 22 and 70°C, respectively, converted them to a near homoionic state in Na-form. Lead and

L. ?urkovi?; Š. Cerjan-Stefanovi?; T. Filipan

1997-01-01

156

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

SciTech Connect

Iron oxide films were deposited onto Si substrates using ion-beam-assisted deposition. The films were ~300 nm thick polycrystalline magnetite with an average crystallite size of ~6 nm. Additionally, incorporation of significant fractions of argon in the films from ion bombardment is evident from chemical analysis, and Fe/O ratios are lower than expected from pure magnetite. However, Raman spectroscopy and x-ray diffraction both indicate that the films are single-phase magnetite. Since no direct evidence of a second phase could be found, exchange bias likely arises due to defects at grain boundaries, possibly amorphous, creating frustrated spins. Since these samples have such small grains, a large fraction of the material consists of grain boundaries, where spins are highly disordered and reverse independently with external field. The high energy deposition process results in an oxygen-rich, argon-containing magnetite film with low temperature exchange bias due to defects at the high concentration of grain boundaries.

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

2014-11-03

157

Thermal analysis for ion-exchange column system  

SciTech Connect

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

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

2012-07-01

158

An Evaluation Method of Chromatographic Parameters from the Ion-Exchange Isotherm of Al?Substituted Tobermorite Cation Exchanger  

Microsoft Academic Search

A new and useful method has been developed for analytical evaluation of the distribution coefficient (Kd) at an infinitesimal exchange. Kd values have an important role for the chromatographic separation of ions. This method is based on the extrapolation of the Kielland plot from an ion-exchange isotherm to zero loading. The usefulness of this method is exemplified by evaluation of

Masamichi Tsuji; Sridhar Komarneni

1991-01-01

159

Negative Joule Heating in Ion-Exchange Membranes  

E-print Network

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

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

2014-02-06

160

Negative Joule Heating in Ion-Exchange Membranes  

E-print Network

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

Biesheuvel, P M; Hamelers, H V M

2014-01-01

161

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

162

Ion-molecule reaction chemistry of ionic transition-metal carbonyl clusters fragments. 1. Ligand-exchange reactions of Cr sub 2 (CO) sub y sup + ions  

SciTech Connect

The ligand-exchange ion-molecule reaction chemistry of Cr{sub 2}(CO){sub y}{sup +} ionic transition metal cluster fragments has been investigated by using a two-section ion cell Fourier transform ion cyclotron resonance mass spectrometer. Simple ligand-exchange reactions involving ligand (L) addition followed by metal-ligand (M---CO) bond cleavage (i.e., an associative ligand-exchange mechanism) as well as ligand exchange involving metal-metal cleavage (i.e. addition of L to Cr{sub 2}(CO){sub y}{sup +} followed by metal-metal bond cleavage) are observed. The branching ratios for reactions involving metal-metal bond cleavage increase as the metal-to-ligand ratio decreases. In addition, the ratio for simple ligand exchange to metal-metal bond cleavage is strongly dependent upon the nature of the reacting ligand (L). These data combined with collision-induced dissociation data for Cr{sub 2}(CO){sub y}{sup +} ionic cluster fragments suggest that the Cr-Cr bond strength decreases as y is increased; i.e., the Cr---Cr bond order is strongly dependent upon the ligand environment.

Sellers-Hahn, L.; Russell, D.H. (Texas A and M Univ., College Station (USA))

1990-08-01

163

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

164

Ion-exchange micro columns for on-line preconcentration of heavy metals I. A rapid voltammetric screening test of ion-exchange kinetics  

Microsoft Academic Search

Summary A screening test for the investigation of the kinetical behaviour of ion-exchange materials is described. The test enables to decide within a short time which resin may be suitable for a special preconcentration problem. It is based on voltammetric measurements carried out in a single vessel. Using Zn, Cd, Pb and Cu, seventeen ion-exchange materials were checked. Experimental conditions

G. Schulze; O. Elsholz

1989-01-01

165

Ion-exchangeable, electronically conducting layered perovskite oxyfluorides.  

PubMed

Cation-exchangeable d(0) layered perovskites are amenable to intercalation, exfoliation, and a variety of topochemical reactions, but they lack the interesting electronic and magnetic functionalities of mixed-valent perovskites. Conversely, electronically and magnetically interesting layered perovskites lack scope in terms of interlayer chemistry. To bridge this gap, the insulating, cation-exchangeable layered perovskites RbLaNb(2)O(7), KCa(2)Nb(3)O(10), and NaYTiO(4) were reacted with poly(tetrafluoroethylene) under inert atmosphere conditions to yield layer perovskites in which some of the oxygen is substituted by fluorine. In the fluorinated materials, the B-site cations are reduced to a mixed-valent state without introducing oxygen vacancies into the anion sublattice. The resulting electronically conducting solids can be exposed to air and water and even ion-exchanged in acid without oxidation of the B-site cations. Electronic transport measurements on the air-stable RbLaNb(2)O(6)F reveal room-temperature conductivity (2-7 x 10(2) ohms x cm) via a variable-range hopping mechanism, which is not substantially changed after aqueous proton exchange to H(1-x)Rb(x)LaNb(2)O(6)F (x approximately = 0.2). PMID:19548670

Kobayashi, Yoji; Tian, Mingliang; Eguchi, Miharu; Mallouk, Thomas E

2009-07-22

166

The role of the alkali metal co-cation in the ion exchange of Y zeolites IV. Cerium ion exchange equilibria  

Microsoft Academic Search

Ion exchange isotherms at 298 K describing the uni-trivalent exchange of LiY, NaY, KY, RbNaY and CsNaY with Ce3+ at total normality 0.1 mol equiv.?1 are presented. The out-going cation has a considerable influence on the progress of exchange and the overall preference of the zeolite phase for the entering Ce3+ ions decreases in the order LiY > NaY >

Mark A. Keane

1996-01-01

167

Protonation and ion exchange equilibria of weak base anion-exchange resins.  

PubMed

Protonation and ion exchange equilibria of weak base anion-exchange resins, in which tertiary amine moieties were introduced as a functional group, were investigated by applying NMR spectroscopy to species adsorbed into the resins. (31)P NMR signals of the phosphinate ion in the resin phases shifted to a lower field due to the influence of protonation of the tertiary amine groups of the resins in the pH range of 4-10. Protonation constants of the tertiary amine groups in styrene-divinylbenzene (DVB)-based resins were estimated to be K(H)=10(6.4) for Amberlite IRA96 and 10(6.5) for DIAION WA30 by the (31)P NMR method using the phosphinate ion as a probe species. In addition to the low field shift caused by the protonation of the tertiary amine moieties, another low field shift was observed for the phosphinate ion in acrylic acid-DVB-based resins at a rather high pH. This shift should be due to an unexpected deprotonation in the acrylic resin: a tautomerism accompanying the proton release from the amide form to the imide one in the functional group, thus, the resin could exhibit a cation exchange property at the high pH. Protonation constants of the tertiary amine moieties in the acrylic resins were estimated to be 10(8.8) for DIAION WA10, 10(9.0) for Amberlite IRA67 and 10(9.3) for Bio-Rad AG 4-X4 on the basis of the Henderson-Hasselbalch equation using the resin phase pH estimated by the (133)Cs and (1)H NMR signal intensities. PMID:21872022

Miyazaki, Yoshinobu; Nakai, Mariko

2011-09-30

168

Ion Exchange Testing with SRF Resin FY 2012  

SciTech Connect

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

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

2014-07-02

169

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

170

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

171

Position-specific measurement of oxygen isotope ratios in cellulose: Isotopic exchange during heterotrophic cellulose synthesis  

NASA Astrophysics Data System (ADS)

We describe the first reported method for the measurement of oxygen isotope ratios at each position in the glucose units of the cellulose molecule. The overall process comprises a series of synthetic organic sequences, by which ?-cellulose is hydrolysed to glucose, and oxygen atoms at specific positions in the glucose molecule are removed in samples of benzoic acid for measurement of ?18O. Values of ?18O at specific positions in cellulose are calculated from these ?18O values and the overall ?18O value of the cellulose. We apply the method to determine the degree to which oxygen atoms at each position undergo isotopic exchange with water during heterotrophic cellulose synthesis, such as occurs in the cambium of trees. To do this we extract ?-cellulose from wheat seedlings germinated in the dark in aqueous media of differing oxygen isotope ratios. Results indicate that oxygen atoms at positions 5 and 6 (O-5 and O-6 respectively) undergo around 80% exchange with medium water, O-3 undergoes around 50% exchange, and O-2 and O-4 do not undergo isotopic exchange. The results have important implications for extracting palaeoclimatic records from oxygen isotope time series obtained from tree ring cellulose. As O-5 and O-6 undergo significant exchange with medium water during heterotrophic cellulose synthesis, oxygen isotopes at these positions in tree ring cellulose should carry a predominantly trunk (source) water signal. On the other hand, O-2 and O-4 should retain the isotopic signature of leaf water in tree ring cellulose. Our method therefore potentially enables the separate reconstruction of past temperature and humidity data from oxygen isotope ratios of tree ring cellulose - something that has hitherto not been possible. The measured degrees of isotopic exchange are to some extent unexpected and cannot be fully explained using current biochemical mechanisms, suggesting that knowledge of these processes is incomplete.

Waterhouse, John S.; Cheng, Shuying; Juchelka, Dieter; Loader, Neil J.; McCarroll, Danny; Switsur, V. Roy; Gautam, Lata

2013-07-01

172

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

PubMed

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

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

2000-01-01

173

SERS enhancement of Ag nanoparticle patterns embedded in glass by two-step ion exchange  

NASA Astrophysics Data System (ADS)

Silver nanoparticles embedded in glass are prepared by two different two-step ion exchange methods. In both of these methods, silver ions are introduced into glass in the first silver ion exchange step, but silver ions are reduced into metallic silver using two different second process steps: either post-annealing or subsequent potassium ion exchange. The formed particles are characterized by optical absorption measurements, scanning electron microscopy, transmission electron microscopy and atomic force microscopy. Their application in SERS is demonstrated, and the optimal surface features in terms of SERS enhancement are discussed. With post-annealing, high iron content in glass is needed to achieve high concentration of silver metal nanoclusters. Using double ion exchange, with the second step of potassium ion exchange, reduction of silver ions into metal nanoclusters occurs below aluminium mask. Using such mask, fabrication of silver nanoparticle patterns is also demonstrated.

Karvonen, Lasse; Chen, Ya; Säynätjoki, Antti; Tervonen, Ari; Honkanen, Seppo

2012-03-01

174

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

175

Competitive Ion Exchange Behavior on Oxides C. P. Schulthess* and D. L. Sparks  

E-print Network

Competitive Ion Exchange Behavior on Oxides C. P. Schulthess* and D. L. Sparks ABSTRACT Cation between the ions in solution and the oxide surface. Cation adsorption studies were also used to determine review several topics related to ion exchange modeling and data interpretation; emphasis is placed

Sparks, Donald L.

176

Calculation of stopping power ratios for carbon ion dosimetry  

NASA Astrophysics Data System (ADS)

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

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

2006-05-01

177

Calculation of stopping power ratios for carbon ion dosimetry.  

PubMed

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

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

2006-05-01

178

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

179

Ion exchange at TNX using the SKID unit  

SciTech Connect

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

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

1993-10-21

180

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

2006-01-01

181

Ion-exchanged glass DFB lasers for DWDM  

NASA Astrophysics Data System (ADS)

Nowadays, optical telecommunication systems require an increasing bit-rate. For this reason Dense Wavelength Division Multiplexing (DWDM) systems are currently under development. They need optical sources with a narrow and stable emission spectrum in the C band which should also integrate several emission wavelengths. Glass waveguide lasers enable both the sharp linewidth of optical fiber lasers and the integration possibilities of semiconductor lasers. In this paper, the realization of ion-exchanged waveguide DFB lasers on glass substrates is presented. Phosphate Er-Yb-codoped glass integrated lasers are first investigated for different doping concentrations. The characteristics of these lasers are then compared : each one have low threshold and exhibit single mode output power of several milliwatt for 100 mW launched pump power. The effect of a passivation layer is then studied. Its modelling and experiment shows that the emitted power can be increased by reducing pump scattering losses. Thanks to the use of silver ion exchange technology, a high index increase is obtained which induces an important variation of the waveguide's effective index with its width. Thus, the emission of 15 channels roughly placed on the 100 GHz ITU grid is demonstrated.

Blaize, Sylvain; Bastard, Lionel; Cassagnetes, Cedric; Vitrant, Guy; Broquin, Jean-Emmanuel

2002-06-01

182

Electron capture branching ratio measurements in an ion trap for double beta decay experiments at TITAN  

NASA Astrophysics Data System (ADS)

Double beta decay (??) is a nuclear decay mode expected to appear in at least two varieties, the double-neutrino (2?) and the zero-neutrino (0?) mode. The 0???-decay is of particular interest as it requires the neutrino to be a Majorana particle. The search for such a decay is presently being carried out or planned in a number of experiments, such as EXO, MAJORANA, GERDA, CUORE, COBRA, NEMO-III and SNO+. The 0?-decay rate depends on the neutrino mass but, unfortunately, also on a rather complex nuclear matrix element, making the extraction of the mass heavily dependent on the underlying theoretical nuclear model. However, all theoretical models can readily be tested against the 2? mode, which, unlike its 0? counterpart, only involves simple Gamow Teller nuclear matrix elements. These elements can be determined experimentally either through charge-exchange reactions or, for the ground-state transition, through the electron capture (EC) or single ?-decay of the intermediate odd odd nucleus. The present program is geared towards the measurement of the EC branching ratios (BR). In most cases, these ratios are poorly known or not known at all, because EC is usually suppressed by several orders of magnitude compared to the ?-decay counterpart due to energy considerations. Traditional methods for measuring these ratios have so far suffered from overwhelming background generated by these high-energy electrons. Recently, a unique background-free method for measuring EC branching ratios was proposed using the TITAN ion trap at the TRIUMF ISAC (Isotope Separator and ACcelerator) radioactive beam facility. The measurements will make use of the EBIT (Electron Beam Ion Trap) operating in Penning mode where electrons from the ?--decay will be confined by the magnetic field. K-shell X-rays from EC will be detected by seven X-ray detectors located around the trap, thus providing orders of magnitude background suppression and thus ideal low-BR measurement environment.

Brunner, T.; Brodeur, M.; Champagne, C.; Frekers, D.; Krücken, R.; Lapierre, A.; Delheij, P.; Ringle, R.; Ryjkov, V.; Smith, M.; Tanihata, I.; Dilling, J.

2008-10-01

183

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

184

Novel ion-exchange membranes for electrodialysis prepared by radiation-induced graft polymerization  

Microsoft Academic Search

Ion-exchange membranes have been used to concentrate seawater to produce salt as well as to desalinate brackish water to render it potable. Also, the interest in applications of ion-exchange membranes as separators for electrodialytic desalination of bioproducts and separators in hydrogen-oxygen fuel cells has been growing. Novel ion-exchange membranes containing sulfonic acid (SOâH) and trimethyl ammonium [N(CHâ)â] groups were prepared

Satoshi Tsuneda; Kyoichi Saito; Hisashi Misuhara; Takanobu Sugo

1995-01-01

185

On the significance of the respiratory exchange ratio after different diets during exercise in man.  

PubMed

Total respiratory exchange ratio (R) was compared to the respiratory exchange ratio over the legs (RQL) during exercise after different diets, to evaluate if R (which represents a mean for the whole body) can be used to estimate the relative proportions of fat and carbohydrate oxidation in exercising muscle. One important prerequisite for this is a steady state acid base balance, 7 subjects were studied at rest and during the later part of a 25 min exercise (65% of Vo2 max) on two occasions, the first preceded by a fat rich diet and the second by a carbohydrate rich diet. Oxygen uptake, R and arterial-femoral venous differences for [O2], [CO2], PCO2 and pH and arterial concentrations for lactate and beta-hydroxybutyrate were measured. Respiratory exchange ratio over the exercising legs (RQL) and ventilation/oxygen uptake were calculated. Arterial pH, PCO2, lactate and beta-hydroxybutyrate as well as specific ventilation attained steady levels during the later part of exercise after both diets. Although arterial lactate and beta-hydroxybutyrate differed between the diets, the arterial pH and specific ventilation were the same. Both R and RQL were higher after the carbohydrate than after the fat diet and there was no systematic difference between R and RQL. Therefore, it seems likely that R estimates the proportion of fat and carbohydrate oxidation in skeletal muscle during submaximal exercise after extreme diets. PMID:6814192

Jansson, E

1982-01-01

186

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

187

Small Column Ion Exchange Design and Safety Strategy  

SciTech Connect

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

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

2011-02-07

188

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

189

Copper ion-exchanged channel waveguides optimization for optical trapping.  

PubMed

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

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

2013-08-01

190

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

191

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 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.

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

2010-06-15

192

Influence of the ion/neutral atom mass ratio on the damping of electrostatic ion-cyclotron waves  

NASA Technical Reports Server (NTRS)

The damping of electrostatic ion-cyclotron waves by ion-neutral collisions was studied in a single-ended Q machine. The amplitudes of K(+) and Cs(+) electrostatic ion-cyclotron waves were measured as a function of neutral pressure in helium, neon, argon, krypton, and xenon. For each ion/neutral atom combination, the electrostatic ion-cyclotron wave amplitude maximizes at a neutral pressure that scales monotonically with the m(+)/m(n) mass ratio. This result is interpreted by considering the dynamics of elastic collisions between the ions and the neutral atoms.

Suszcynsky, D. M.; Cartier, S. L.; D'Angelo, N.; Merlino, R. L.

1987-01-01

193

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

194

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

195

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

Microsoft Academic Search

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

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

2012-01-01

196

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.)

Not Available

1993-12-01

197

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

NONE

1996-01-01

198

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

199

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

200

Relation between the ordinary and extraordinary index profiles of ion-exchanged glass waveguides.  

PubMed

The relation between the ordinary and extraordinary index profiles of ion-exchanged glass waveguides is investigated on the basis of the stress-optic law and the Clausius-Mossotti relation. For K(+) exchange and Ag(+) exchange, the experimental results are consistent with our analysis. The values of the coefficient that relates the ordinary and extraordinary index profiles are presented. PMID:19745917

Tsutsumi, K; Hirai, H; Yuba, Y

1988-05-01

201

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

202

Disinfection of viable Pseudomonas stutzeri in ultrapure water with ion exchange resins  

Microsoft Academic Search

This study describes the disinfection of gram-negative bacteria, Pseudomonas stutzeri, isolated from ultrapure water (total organic carbon 5 ppb; effluent resistivity, > 18 M? cm at 25°C) with ion exchange resins using a batchwise procedure. A single bed of strong base anion exchange resin (SBAER) in OH? form shows disinfection ability; however, a bed of strong acid cation exchange resin

Nae Matsuda; Wataru Agui; Keizo Ogino; Norimichi Kawashima; Tokeru Watanabe; Hideki Sakai; Masahiko Abe

1996-01-01

203

Silver structure environments in ion-exchanged silicate glasses studied by X-ray absorption fine structure.  

PubMed

X-ray absorption fine structure (XAFS) technique was used to analyze structural geometry of Ag atoms introduced into soda-lime silicate glass and soda aluminosilicate glass by ion-exchange method. The results show that Ag+ ion in soda aluminosilicate glass takes a coordination number of 1.6 with a Ag-O distance of 2.20 A when the ion-exchange ratio x is smaller than 0.47 and of 2.28 A when x is larger than 0.47. The introduced Ag+ ions are stabilized at the non-bridge oxygen (NBO) sites when x is lower than 0.47. The Na+ ions in AlO4 (O4 represents the bridging oxygen) sites are exchanged by Ag+ ions after all Na+ in NBO sites are replaced. The disorder of Ag-O coordination increases gradually with increasing x from 0.24 to 0.47 in soda aluminosilicate glass and increases dramatically when x is larger than 0.47. Ag+ ions takes a coordination number of 1.6 in the ion-exchanged soda-lime silicate glass and of 1.3 after subsequently thermal treatment with the same Ag-O distance of 2.14 A. Debye-Waller factor (DWF) of Ag-O coordination in soda aluminosilicate glass is higher than that in soda-lime silicate glass. Small Ag cluster has a reduced interatomic distance and a larger DWF. Ag nanoparticle in sample Ag-7 is in a state of tensile stress. PMID:19441594

Yang, X C; Li, W J; Dubiel, M; Huang, W H; Yano, T

2009-02-01

204

Separation kinetics of l-phenylalanine by ion-exchange process  

Microsoft Academic Search

Ion-exchange kinetics of l-phenylalanine (Phe) by strongly acidic cation-exchange resin Amberlite IR 120-P was investigated. Phe+\\/H+ equilibrium isotherms were obtained in a wide range of pH and temperature and the related equilibrium models were determined. The effects of pH, temperature, feed stream volumetric flow rate and feed stream Phe concentration were investigated in a differential ion-exchange column (DIC) and pH=5.0,

Serpil Takaç; Güzide Çal?k; Meryem Aytar; Tunçer H. Özdamar

1998-01-01

205

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

NASA Astrophysics Data System (ADS)

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

Khokhlova, O. N.

2014-08-01

206

Ion Exchange Technology Development in Support of the Urine Processor Assembly  

NASA Technical Reports Server (NTRS)

The urine processor assembly (UPA) on the International Space Station (ISS) recovers water from urine via a vacuum distillation process. The distillation occurs in a rotating distillation assembly (DA) where the urine is heated and subjected to sub-ambient pressure. As water is removed, the original organics, salts, and minerals in the urine become more concentrated and result in urine brine. Eventually, water removal will concentrate the urine brine to super saturation of individual constituents, and precipitation occurs. Under typical UPA DA operating conditions, calcium sulfate or gypsum is the first chemical to precipitate in substantial quantity. During preflight testing with ground urine, the UPA achieved 85% water recovery without precipitation. However, on ISS, it is possible that crewmember urine can be significantly more concentrated relative to urine from ground donors. As a result, gypsum precipitated in the DA when operating at water recovery rates at or near 85%, causing the failure and subsequent re14 NASA Tech Briefs, September 2013 placement of the DA. Later investigations have demonstrated that an excess of calcium and sulfate will cause precipitation at water recovery rates greater than 70%. The source of the excess calcium is likely physiological in nature, via crewmembers' bone loss, while the excess sulfate is primarily due to the sulfuric acid component of the urine pretreatment. To prevent gypsum precipitation in the UPA, the Precipitation Prevention Project (PPP) team has focused on removing the calcium ion from pretreated urine, using ion exchange resins as calcium removal agents. The selectivity and effectiveness of ion exchange resins are determined by such factors as the mobility of the liquid phase through the polymer matrix, the density of functional groups, type of functional groups bound to the matrix, and the chemical characteristics of the liquid phase (pH, oxidation potential, and ionic strength). Previous experience with ion exchange resins has demonstrated that the most effective implementation for an ion exchange resin is a cartridge, or column, in which the resin is contained. Based on the results of equilibrium and sub-scale dynamic column testing, a possible solution for mitigating the calcium precipitation issue on the ISS has been identified. From an original pool of 13 ion exchange resins, two candidates have been identified that demonstrate substantial calcium removal on the sub-scale. The dramatic reduction in resin performance from published calcium uptake demonstrates the need for thorough evaluation of resins at the low pH and strong oxidizing environment present in the UPA. Chemical variations in the influent (calcium concentrations and pretreatment dosing) appear to have a noticeable impact on the calcium capacity of the resin. Low calcium concentrations and high pretreatment dosing will likely result in a decrease in calcium capacity. Conversely, low pre trea t - ment dosing will likely result in an increase in calcium capacity. In contrast, investigations at a variety of flow rates, length-to-diameter ratios, resin volumes, and flow regimes (continuous versus pulsed) show that changes in physical parameters do not have substantial impacts on resin performance in the very low specific velocity ranges of interest. This result is particularly useful because most commercial applications at higher specific velocities do show a relatively strong relationship between flow and capacity. The lack of a strong relationship will allow more flexibility in the implementation of an ion exchange bed for flight. Verification of subscale tests with flight-scale resin beds is recommended prior to implementation in the on-orbit UPA.

Mitchell, Julie; Broyan, James; Pickering, Karen

2013-01-01

207

Lead Removal From Synthetic Leachate Matrices by a Novel Ion-Exchange Material  

NASA Technical Reports Server (NTRS)

This report discusses the application of a novel polyacrylate-based ion-exchange material (IEM) for the removal of lead (Pb) ions from water. Preliminary testing includes the establishment of the operating pH range, capacity information, and the effect of calcium and anions in the matrix. Batch testing with powder indicates slightly different optimal operational conditions from those used for column testing. The ion exchanger is excellent for removing lead from aqueous solutions.

Street, Kenneth W., Jr.; Hovanitz, Edward S.; Chi, Sulan

2002-01-01

208

THERMAL MODELING OF ION EXCHANGE COLUMNS WITH SPHERICAL RF RESIN  

SciTech Connect

Models have been developed to simulate the thermal performance of RF columns fully loaded with radioactive cesium. Temperature distributions and maximum temperatures across the column were calculated during Small Column Ion Exchange (SCIX) process upset conditions with a focus on implementation at Hanford. A two-dimensional computational modeling approach was taken to include conservative, bounding estimates for key parameters such that the results will provide the maximum centerline temperatures achievable under the design configurations using a feed composition known to promote high cesium loading on RF. The current full-scale design for the SCIX system includes a central cooling tube, and one objective of these calculations was to examine its elimination to simplify the design. Results confirmed that a column design without a central cooling tube is feasible for RF, allowing for the possibility of significant design simplifications if it can be assumed that the columns are always filled with liquid. With active cooling through the four outer tubes, the maximum column diameter expected to maintain the temperature below the assumed media and safety limits is 26 inches, which is comparable to the current design diameter. Additional analysis was conducted to predict the maximum column temperatures for the previously unevaluated accident scenario involving inadvertent drainage of liquid from a cesium-saturated column, with retention of the ion exchange media and cesium in the column. As expected, much higher maximum temperatures are observed in this case due to the poor heat transfer properties of air versus liquid. For this hypothetical accident scenario involving inadvertent and complete drainage of liquid from a cesium-saturated column, the modeling results indicate that the maximum temperature within a 28 inch diameter RF column with external cooling is expected to exceed 250 C within 2 days, while the maximum temperature of a 12 inch column is maintained below 100 C. In addition, the calculation results demonstrate that the cooling tube system external to an air-filled column is not highly effective at reducing the maximum temperature, but the baseline design using a central cooling tube inside the column provides sufficient cooling to maintain the maximum temperature near the assumed safety limit.

Lee, S.; King, W.

2009-12-30

209

Specific features of the luminescence of silicate glasses with silver introduced by ion exchange  

NASA Astrophysics Data System (ADS)

The luminescence spectra of silicate glasses with silver introduced by ion exchange have been investigated. It is shown that silver introduced into glass by ion exchange exists not only in the form of ions, but also as neutral atoms and charged and neutral molecular clusters, which provide intense luminescence in the visible spectral range. Cerium ions in glass facilitate the formation of neutral molecular silver clusters, due to which the luminescence intensity increases. It is shown that Ag n -Ce x+ complexes can be formed in glass containing cerium ions and neutral molecular silver clusters.

Demichev, I. A.; Ignat'ev, A. I.; Nikonorov, N. V.; Sgibnev, E. M.; Sidorov, A. I.; Khrushcheva, T. A.; Shakhverdov, T. A.

2014-04-01

210

An evaluation method of chromatographic parameters from the ion-exchange isotherm of Al sup 3+ -substituted tobermorite cation exchanger  

SciTech Connect

A new and useful method has been developed for analytical evaluation of the distribution coefficient (K{sub d}) at an infinitesimal exchange. K{sub d} values have an important role for the chromatographic separation of ions. This method is based on the extrapolation of the Kielland plot from an ion-exchange isotherm to zero loading. The usefulness of this method is exemplified by evaluation of K{sub d} values for Cs{sup +} on Al{sup 3+}-substituted tobermorite which is known to exhibit high selectivity toward Cs{sup +}.

Tsuji, Masamichi; Komarneni, S. (Pennsylvania State Univ., University Park (USA))

1991-01-01

211

Protein-surface interaction maps for ion-exchange chromatography.  

PubMed

In this paper, protein-surface interaction maps were generated by performing coarse-grained protein-surface calculations. This approach allowed for the rapid determination of the protein-surface interaction energies at a range of orientations and distances. Interaction maps of lysozyme indicated that there was a contiguous series of orientations corresponding to several adjacent preferred binding regions on the protein surface. Examination of these orientations provided insight into the residues involved in surface interactions, which qualitatively agreed with the retention data for single-site mutants. Interaction maps of lysozyme single-site mutants were also generated and provided significant insight into why these variants exhibited significant differences in their chromatographic behavior. This approach was also employed to study the binding behavior of CspB and related mutants. The results indicated that, in addition to describing general trends in the data, these maps provided significant insight into retention data of the single-site mutants. In particular, subtle retention trends observed with the K12 and K13 mutants were well-described using this interaction map approach. Finally, the number of interaction points with energies stronger than -2 kcal/mol was shown to be able to semi-quantitatively predict the behavior of most of the mutants. This rapid approach for calculating protein-surface interaction maps is expected to facilitate future method development for separating closely related protein variants in ion-exchange systems. PMID:21375221

Freed, Alexander S; Cramer, Steven M

2011-04-01

212

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

213

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

214

Ion exchange pretreatment of alkaline radwaste for cesium removal  

SciTech Connect

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

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

1994-08-01

215

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

216

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

DOEpatents

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

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

2001-01-01

217

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

DOEpatents

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

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

2002-01-01

218

Charge-exchange plasma environment for an ion drive spacecraft  

NASA Technical Reports Server (NTRS)

A model was reviewed which describes the propagation of the mercury charge-exchange plasma and extended to describe the flow of the molybdenum component of the charge-exchange plasma. The uncertainties in the models for various conditions are discussed. Such topics as current drain to the solar array, charge-exchange plasma material deposition, and the effects of space plasma on the charge-exchange plasma propagation are addressed.

Kaufman, H. R.; Carruth, M. R., Jr.

1981-01-01

219

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

SciTech Connect

Preface The theme of supramolecular chemistry (SC), entailing the organization of multiple species through noncovalent interactions, has permeated virtually all aspects of chemical endeavor over the past several decades. Given that the observed behavior of discrete molecular species depends upon their weak interactions with one another and with matrix components, one would have to conclude that SC must indeed form part of the fabric of chemistry itself. A vast literature now serves to categorize SC phenomena within a body of consistent terminology. The word supramolecular itself appears in the titles of dozens of books, several journals, and a dedicated encyclopedia. Not surprisingly, the theme of SC also permeates the field of solvent extraction (SX), inspiring the framework for this volume of Ion Exchange and Solvent Extraction. It is attempted in the six chapters of this volume to identify both how supramolecular behavior occurs and is studied in the context of SX and how SC is influencing the current direction of SX. Researchers and practitioners have long dealt with supramolecular interactions in SX. Indeed, the use of polar extractant molecules in nonpolar media virtually assures that aggregative interactions will dominate the solution behavior of SX. Analytical chemists working in the 1930s to the 1950s with simple mono- and bidentate chelating ligands as extractants noted that extraction of metal ions obeyed complicated mass-action equilibria involving complex stoichiometries. As chemists and engineers developed processes for nuclear and hydrometallurgical applications in the 1950s and 1960s, the preference for aliphatic diluents only enhanced the complexity and supramolecular nature of extraction chemistry. Use of physical techniques such as light scattering and vapor-pressure measurements together with various spectroscopic methods revealed organic-phase aggregates from well-defined dimers to small aggregates containing a few extractant molecules to large inverse micelles swollen with water molecules. Extraction systems involving long-chain cations such as alkylammonium species or long-chain anions such as sulfonates or carboxylates proved especially prone to extensive aggregate formation. The related phenomenon of third-phase formation in SX systems, long misunderstood, is now yielding to spectroscopic and scattering techniques showing extensive long-range organization. Over the last 50 years, tools for studying the structure and thermodynamics of aggregation have grown increasingly sophisticated, leading to a rich and detailed understanding of what we can now recognize as SC phenomena in SX. In the 1970s and 1980s, the rapid growth of SC elicited a paradigm shift in SX. The influence of SC principles had two major effects on the course of SX research. First, it provided a framework for understanding the supramolecular behavior that was already well appreciated in the field of SX, though earlier without the SC terminology. Second, it provided the conceptual tools to control supramolecular behavior in SX, direct it for intended functionality, and to simplify it. Extraction by designed reagents has been steadily progressing ever since, with commercial applications emerging to successfully validate this approach. With the discovery of crown ethers in the late 1960s, the advancement of extractant design has fruitfully employed the concept of inclusion. While considerable initial progress occurred with such molecules, especially because of their affinity and selectivity for alkali and alkaline earth metals, other molecular platforms such as calixarenes have proven more versatile. Multidentate receptors for partial to full inclusion of cations, anions, ion pairs, as well as neutral species, have now become commonplace for selective extraction. This volume of Ion Exchange and Solvent Extraction examines how the principles of SC are being employed both in advancing the design of new highly selective SX systems and in understanding aggregation phenomena in SX systems. Chapter 1 discusses the nature and definition of SC

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

2013-01-01

220

Quantitative chemical exchange saturation transfer (qCEST) MRI--RF spillover effect-corrected omega plot for simultaneous determination of labile proton fraction ratio and exchange rate.  

PubMed

Chemical exchange saturation transfer (CEST) MRI is sensitive to dilute proteins and peptides as well as microenvironmental properties. However, the complexity of the CEST MRI effect, which varies with the labile proton content, exchange rate and experimental conditions, underscores the need for developing quantitative CEST (qCEST) analysis. Towards this goal, it has been shown that omega plot is capable of quantifying paramagnetic CEST MRI. However, the use of the omega plot is somewhat limited for diamagnetic CEST (DIACEST) MRI because it is more susceptible to direct radio frequency (RF) saturation (spillover) owing to the relatively small chemical shift. Recently, it has been found that, for dilute DIACEST agents that undergo slow to intermediate chemical exchange, the spillover effect varies little with the labile proton ratio and exchange rate. Therefore, we postulated that the omega plot analysis can be improved if RF spillover effect could be estimated and taken into account. Specifically, simulation showed that both labile proton ratio and exchange rate derived using the spillover effect-corrected omega plot were in good agreement with simulated values. In addition, the modified omega plot was confirmed experimentally, and we showed that the derived labile proton ratio increased linearly with creatine concentration (p < 0.01), with little difference in their exchange rate (p = 0.32). In summary, our study extends the conventional omega plot for quantitative analysis of DIACEST MRI. PMID:24706610

Sun, Phillip Zhe; Wang, Yu; Dai, ZhuoZhi; Xiao, Gang; Wu, Renhua

2014-01-01

221

Determination of 16O and 18O sensitivity factors and charge-exchange processes in low-energy ion scattering  

NASA Astrophysics Data System (ADS)

Quantitative analysis in low-energy ion scattering (LEIS) requires an understanding of the charge-exchange processes to estimate the elemental sensitivity factors. In this work, the neutralization of He+ scattered by 18O-exchanged silica at energies between 0.6 and 7 keV was studied. The process is dominated by Auger neutralization for Ei < 0.8 keV. An additional mechanism starts above the reionization threshold. This collision-induced neutralization becomes the dominant mechanism for Ei > 2 keV. The ion fractions P+ were determined for Si and O using the characteristic velocity method to quantify the surface density. The 18O/16O sensitivity ratio indicates an 18% higher sensitivity for the heavier O isotope.

Téllez, H.; Chater, R. J.; Fearn, S.; Symianakis, E.; Brongersma, H. H.; Kilner, J. A.

2012-10-01

222

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

223

Preliminary Ion Exchange Modeling for Removal of Cesium from Hanford Waste Using Hydrous Crystalline Silicotitanate Material  

SciTech Connect

For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP), the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based on SuperLig(R) 644 resin. Due to recent concerns over potential radiological and chemical degradation of SuperLig(R) 644 resin and increased pressure drops observed during pilot-scale column studies, an increased interest in developing a potential backup ion-exchanger material has resulted. Ideally, a backup ion-exchanger material would replace the SuperLig(R) 644 resin and have no other major impacts on the pretreatment facility flowsheet. Such an ideal exchanger has not been identified to date. However, Crystalline Silicotitanate (CST) ion-exchanger materials have been studied for the removal of cesium from a variety of DOE wastes over the last decade. CST ion-exchanger materials demonstrate a high affinity for cesium under high alkalinity conditions and have been under investigation for cesium removal specifically at Hanford and SRS during the last six years. Since CST is an inorganic based material (with excellent properties in regard to chemical, radiological, and thermal stability) that is considered to be practically non-elutable (while SuperLig(R) 644 is an organic based elutable resin), the overall pretreatment facility flowsheet would be impacted in various ways. However, the CST material is still being considered as a potential backup ion-exchanger material. The performance of a proposed backup ion-exchange column using IONSIV IE-911 (CST in its engineered-form) material for the removal of cesium from Hanford high level radioactive alkaline waste is discussed. This report focuses attention on the ion-exchange aspects and addresses the loading phase of the process cycle.

HAMM, LUTHER L.

2004-07-27

224

Tramadol loading, release and iontophoretic characteristics of ion-exchange fiber.  

PubMed

The objective of this study was to investigate the drug loading, release and iontophoretic characteristics of strong acidic ion-exchange fiber, using tramadol hydrochloride as a model drug. The complex of charged model drug and ion-exchange fiber was studied as a new approach to achieve controlled drug delivery. Structural characterization of the fiber was elucidated through different approaches including differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and infrared spectroscopy (IR). And the mechanism of drug binding into ion-exchange fibers was validated to be ion-exchange. The drug loading into and release from ion-exchange fiber were affected by the concentration, volume and valence of the counter-ions in the external solution. Iontophoresis could significantly increase the delivery rate and amount of transdermal drug, and the iontophoretic dose could be easily controlled by adjusting the current intensity and the amount of release medium. The tramadol could be steadily released both from the drug-loaded fiber and drug solution when applied the iontophoretic method, which was in disagreement with the previous publications. As a drug reservoir, ion-exchange fiber has good regularity of drug loading, release and iontophoretic characteristics. PMID:24530391

Gao, Yanan; Yuan, Jing; Liu, Hongzhuo; Yang, Yang; Hou, Yanlong; Li, Sanming

2014-04-25

225

Experimental Findings On Minor Actinide And Lanthanide Separations Using Ion Exchange  

SciTech Connect

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

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

2013-09-17

226

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

227

Design, optimization, and selectivity of inorganic ion-exchangers for radioactive waste remediation  

E-print Network

studies because of their ion-exchange properties tunable by alterations of synthetic procedures, and isomorphous framework substitution. The Nb-substitution in titanium sites reduces the framework charge, whereas Ge substitution decreases the unit cell...

Medvedev, Dmitry Gennadievich

2005-11-01

228

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

229

A novel electrochemical ion exchange system and its application in water treatment.  

PubMed

A novel electrochemical ion exchange system with porous cylinder electrodes is proposed for treatment of wastewater. This system can be used for desalination without the costly ion-exchange membrane and extra chemical reagents. Since the electrodes are completely uniform and no ion-exchange membrane was used in this system, it can be operated by switching anodes and cathodes flexibly for eliminating the scaling on the surface of electrodes. The strong base ion-exchange resin grains placed among the anode and cathode have played as supporting electrolyte, which is capable for the treatment of wastewater with low conductivity. The concentrated and neutralized anolyte containing chlorine is effective for disinfection and contaminants removal. Under the experimental conditions, the removal percentage of total dissolved salts was 83% and the removal percentage of chemical oxygen demand was 92% without consumption of extra chemical reagents. PMID:25084577

Li, Yansheng; Li, Yongbin; Liu, Zhigang; Wu, Tao; Tian, Ying

2011-06-01

230

Investigating the Use of Ion Exchange Resins for Processing Biodiesel Feedstocks  

E-print Network

feedstocks. Specifically, this research explored using ion exchange resins to remove free fatty acids (FFA) from soybean and waste cooking oils, catalyze transesterification of soybean oil, and catalyze in-situ conversion of dried algal biomass to biodiesel...

Jamal, Yousuf 1973-

2012-11-27

231

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

232

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

233

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

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

234

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

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

235

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

Microsoft Academic Search

Non-elutable crystalline silicotitanate (CST) ion-exchanger materials have been studied for removing cesium from a variety of radioactive wastes at several U.S. DOE sites over the last decade. For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP) in Hanford, the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based

Hang

2002-01-01

236

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

SciTech Connect

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

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

1982-12-03

237

Erbium-doped ion-exchanged waveguide lasers in BK7 glass  

Microsoft Academic Search

Ion-exchange in glass is a simple, flexible technique to realize optical fiber-compatible planar waveguide devices. Recently, neodymium-doped waveguide lasers operating at 1060 and 1300 nm have been demonstrated in this technology. Lasers operating at 1540 nm are desirable for telecommunication applications and the authors report for the first time ion-exchanged waveguide lasers in erbium-doped glass emitting at this wavelength. Lasers

T. Feuchter; E. K. Mwarania; J. Wang; L. Reekie; J. S. Wilkinson

1992-01-01

238

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

239

Effects of Ion-Exchange Treatment on Bromate Formation and Oxidation Efficiency during Ozonation  

E-print Network

water treatment. In this study, we applied several different ion exchangers (i.e., anion exchange resins technologies in advanced drinking water treatment processes along with activated carbon treatment. Ozonation), chlorine-resistant pathogenic organisms, and various micropollutants in drinking water treatment. In Japan

Takada, Shoji

240

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

241

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...

242

Selectivity of MH Ion-Exchange Absorption on Sulfonic Resins in Ternary Solutions  

Microsoft Academic Search

The selectivity of M-H ion-exchange absorption (M = Na or K) on sulfonated acrylonitrile-butadiene-styrene copolymer previously crosslinked with resol has been investigated in ternary MCl-HCOOH-H2O solutions at 298 K. Hypotheses are put forward concerning the factors determining the selectivity of the cation-exchange resins in solutions of weak organic acids.

M. S. Metwally; T. M. Samy

1993-01-01

243

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

NASA Astrophysics Data System (ADS)

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

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

2004-07-01

244

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

PubMed

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

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

2004-07-12

245

Combining ion mobility spectrometry with hydrogen-deuterium exchange and top-down MS for peptide ion structure analysis.  

PubMed

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

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

2014-12-01

246

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

247

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

248

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

PubMed

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

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

2014-02-01

249

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

250

ROTARY FILTER FINES TESTING FOR SMALL COLUMN ION EXCHANGE  

SciTech Connect

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

Herman, D.

2011-08-03

251

Ion exchange selectivity for cross-linked polyacrylic acid  

NASA Technical Reports Server (NTRS)

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

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

1983-01-01

252

SEPARATION OF ZIRCONIUM FROM TITANIUM AND OTHER ELEMENTS BY AN ION EXCHANGE CHROMTOGRAHIC METHOD  

Microsoft Academic Search

The absorption of zirconium and titanium from sulfuric acid solutions ; was studied depending on the acidity of the medium and on the concentration of ; sulfate ions. lt was established that the optimum value of the separation ; coefficient is obtained in 0.1 N sulfuric acid. An ion exchange chromatographic ; method was developed for separating Zr from Ti,

Nabivanets

1962-01-01

253

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

254

Methods for eluting radiocesium from zeolite ion exchange material in a column in the TMI2 reactor containment building  

Microsoft Academic Search

Two alternative procedures were evaluated at Oak Ridge National Laboratory for potential use in eluting the radiocesium from Linde Ionsiv IE-95 zeolite in the pushcart ion exchange column in the TMI-2 containment building. The elution mechanism was iosotopic exchange of the radiocesium with stable cesium. Small zeolite ion exchange columns that had been loaded during ORNL tests of the Submerged

J. B. Knauer; D. O. Campbell; E. D. Collins; L. J. King

1982-01-01

255

An assessment of inorganic ion-exchange materials for the removal of strontium from simulated Hanford tank wastes  

SciTech Connect

Several inorganic ion-exchange materials were evaluated for the removal of strontium from two simulated Hanford tank wastes (NCAW and 101SY-Cs5) using static batch experiments. Sodium titanium silicate, Na{sub 2}Ti{sub 2}O{sub 3}SiO{sub 4} {center_dot} 2H{sub 2}O (NaTS), was the best material in NCAW with a K{sub d} of 2.7 x 10{sup 5} mL/g at a volume-to-mass ratio of 200:1. In the 101SY-Cs5 simulant, strontium extraction was more difficult due to the presence of complexants and consequently K{sub d}s were greatly reduced. Sodium nonatitanate, NaTi, performed best in the presence of these complexants and gave a K{sub d} of 295 mL/g, though none of the materials performed particularly well. Pellets suitable for column studies were synthesized and the ion exchangers evaluated in column studies. Breakthrough curves correlated well with the K{sub d}s obtained from batch experiments with the sodium titanium silicate performing best in NCAW and a pelletized form of sodium nonatitanate performing best in 101SY-Cs5. Both the sodium titanate and the sodium titanosilicate performed better than IONSIV IE-911, a commercially available ion exchanger, in the NCAW simulant, and consequently could be used for the removal of {sup 90}Sr from highly alkaline tank wastes.

Sylvester, P.; Behrens, E.A.; Graziano, G.M.; Clearfield, A. [Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry] [Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry

1999-07-01

256

Automated resource-saving technology of ion-exchange water treatment  

NASA Astrophysics Data System (ADS)

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

Livshits, M.

2015-01-01

257

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

258

Effect of exchange-correlation on quantum ion-acoustic soliton energy  

NASA Astrophysics Data System (ADS)

The electrons exchange-correlation influence on the energy carried by the quantum ion-acoustic soliton (QIAS) is succinctly discussed. Starting from the one-dimensional quantum hydrodynamic model (in which the term of exchange-correlation for electrons is included), a deformed Korteweg-de Vries-like equation is derived. It is found that the QIAS energy experiences a depletion as a result of quantum diffraction. This quantum energy depletion may be counteracted by the exchange-correlation effect. The present work can be viewed as a first step towards the investigation of the exchange-correlation effects on the dynamics of solitary waves in quantum plasmas.

Mebrouk, Khireddine; Tribeche, Mouloud

2014-11-01

259

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2012 CFR

...styrene and divinylbenzene. (2) Sulfonated anthracite coal meeting the requirements of ASTM method D388-38, Class I...base capacity by weight of total exchange capacity [Chemical Abstracts Service name: Oxirane (chloromethyl)-, polymer with...

2012-04-01

260

21 CFR 173.25 - Ion-exchange resins.  

Code of Federal Regulations, 2011 CFR

...styrene and divinylbenzene. (2) Sulfonated anthracite coal meeting the requirements of ASTM method D388-38, Class I...base capacity by weight of total exchange capacity [Chemical Abstracts Service name: Oxirane (chloromethyl)-, polymer with...

2011-04-01

261

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

PubMed

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

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

2014-01-01

262

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

NASA Technical Reports Server (NTRS)

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

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

1976-01-01

263

Ion-exchange sorption and preparative chromatography of biologically active materials  

SciTech Connect

This book presents information on the following topics: the problems of fine physico-chemical biotechnology; types of highly permeable network polyelectrolytes; methods for studying the permeability and porosity of network polyelectrolytes; the conformation state and flexibility of the structural elements of network polyelectrolytes; ion-exchange processes without the sorption of physiologically active substances; ion exchange, hydration, and swelling; nucleosides, nucleotides, alkaloids, sulfonamides, and miscellaneous physiologically active subtances; sharp front formation for the exchange of ions with the same valences; standard quasi-equilibrium frontal chromatography on ionites; sorption kinetics in ionites with structural heterogeneity; experimental investigations of the diffusivities of organic and physiologically active ions in ionite beads; and increasing the efficiency of low-pressure chromatography by using surface-layer and bidispersed ionites.

Samsonov, G.V.

1986-01-01

264

An Assessment of Inorganic Ion-Exchange Materials for the Removal of Strontium from Simulated Hanford Tank Wastes  

Microsoft Academic Search

Several inorganic ion-exchange materials were evaluated for the removal of strontium from two simulated Hanford tank wastes (NCAW and 101SY-Cs5) using static batch experiments. Sodium titanium silicate, Na2Ti2O3SiO4·2H2O(NaTS), was the best material in NCAW with a Kd of 2.7 × 10 mL\\/g at a volume-to-mass ratio of 200:1. In the 101SY-Cs5 simulant, strontium extraction was more difficult due to the

PAUL SYLVESTER; ELIZABETH A. BEHRENS; GINA M. GRAZIANO; ABRAHAM CLEARFIELD

1999-01-01

265

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

266

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

E-print Network

Transpiration efficiency over an annual cycle, leaf gas exchange and wood carbon isotope ratio. Cumulative transpiration was determined by repeatedly weighing the pots with a pallet truck scale. Dry matter that leaf-level processes largely determined variation among the three tropical tree species in whole

Bermingham, Eldredge

267

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

SciTech Connect

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

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

1997-09-01

268

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

PubMed

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

Nagy, Kornél; Redeuil, Karine; Rezzi, Serge

2009-11-15

269

Ion exchange determines iodine-131 concentration in aqueous samples  

NASA Technical Reports Server (NTRS)

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

Fairman, W. D.; Sedlet, J.

1967-01-01

270

Charge Exchange Processes for Highly Charged Ion -Atom, Molecule  

E-print Network

) Charge Exchange Processes of HCI's are very important for understanding the edge plasma behavior process are greatly concerned with the cooling of the plasma. We paid attention to the following thing of Chemistry and Physics #12;The detail of electron transfer process by HCI's-Atom collision has been made

Princeton Plasma Physics Laboratory

271

Improved hydrous oxide ion-exchange compound catalysts  

DOEpatents

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

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

1986-04-09

272

Preparation of catalysts via ion-exchangeable coatings on supports  

DOEpatents

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

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

1986-04-09

273

Ion Exchange Membrane Cathodes for Scalable Microbial Fuel Cells  

E-print Network

two low-cost anion (AEM) and cation (CEM) exchange membranes was compared to that achieved using) generated using an AEM cathode lacking a catalyst. Using a current collector (a stainless steel mesh, 15), ferric iron (16), manganese (17), and perman- ganate (18), have been used as terminal electron

274

NITRATE REMOVAL FROM WATER SUPPLIES BY ION EXCHANGE  

EPA Science Inventory

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

275

NITRATE REMOVAL FROM WATER SUPPLIES BY ION EXCHANGE - EXECUTIVE SUMMARY  

EPA Science Inventory

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

276

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

NASA Astrophysics Data System (ADS)

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

Wu, Weiqiang; Weitz, Eric

2014-10-01

277

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

SciTech Connect

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

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

2013-07-11

278

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

SciTech Connect

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

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

2008-01-01

279

Diphosphonium ion-exchanged montmorillonite for Telon dye removal from aqueous media  

Microsoft Academic Search

Diphosphonium-intercalated montmorillonites were prepared via ion exchange using para, meta and ortho-bis(triphenyl phosphonium methylene)-benzene-dichloride (p-, m- and o-TPhPMB) in quantities not exceeding the cation exchange capacity. Adsorption tests applied to Telon dyes (Red, blue and orange) revealed a significant increase of the maximum adsorption capacity from ca. 11-26 to 110-160mg.g-1 after intercalation. This improvement was explained by an increased organophilic

B. Makhoukhi; M. A. Didi; H. Moulessehoul; A. Azzouz; D. Villemin

2010-01-01

280

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

281

Monte Carlo simulations on the water-to-air stopping power ratio for carbon ion dosimetry.  

PubMed

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. PMID:19472630

Henkner, Katrin; Bassler, Niels; Sobolevsky, Nikolai; Jäkel, Oliver

2009-04-01

282

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

SciTech Connect

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

Steimke, J.L.

2000-12-19

283

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

SciTech Connect

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

NONE

1995-09-01

284

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

SciTech Connect

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

NONE

1996-10-01

285

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

PubMed

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

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

2014-04-01

286

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

287

Sorption of Ni(II) ions from aqueous solution by Lewatit cation-exchange resin  

Microsoft Academic Search

Ion-exchange is an alternative process for uptake of heavy metals from aqueous solutions. In the present study, the sorption of nickel(II) ions from aqueous solution was investigated by using Lewatit MonoPlus SP 112 (strongly acidic, macroporous cation-exchange resin) in a batch adsorption system as a function of pH (2.0–8.0), initial nickel concentration (50–200mg\\/L), resin dosage (0.5–2.0g\\/L), contact time (0.5–3h), and

Nadir Dizge; Bülent Keskinler; Hulusi Barlas

2009-01-01

288

Building 579 waste ion exchange facility characterization report  

SciTech Connect

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

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

1997-03-01

289

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

PubMed

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

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

2014-06-01

290

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

291

Nuclear quantum effects in water exchange around lithium and fluoride ions  

E-print Network

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

Wilkins, David M; Dang, Liem X

2015-01-01

292

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

293

Strategy of intense ion beam accumulation by use of charge exchange injection  

Microsoft Academic Search

Accumulation of ions in a storage ring using charge exchange injection gives the possibility of storing the ion beam with parameters applicable to plasma experiments. Beam quality on the target can be defined by the factor of beam quality Kb=1.5Pa, where P is specific power, and a is beam radius.A simple formula, which allows one to estimate the value of

P. Zenkevich; A. Bolshakov; N. Alexeev; A. Golubev; E. Mustafin; B. Sharkov; I. Hofmann; I. Meshkov; A. Sydorin

2001-01-01

294

Deuterium retention in tungsten after heavy ion damage and hydrogen isotope exchange in PISCES  

NASA Astrophysics Data System (ADS)

The effect of H isotope exchange and radiation damage on the retention of D in W was examined in the PISCES linear plasma device. W samples were treated with D plasma at low sample temperatures (473 K), with a fluence of 1026 ions/m2 and ion energies of 150 eV. Each sample was then exposed to varying doses of H plasma with similar sample temperature and plasma conditions to fluences ranging from 0 to 1026 ions/m2, to examine the effectiveness of isotope exchange as a means of tritium removal. The D(3He, p)4He nuclear reaction was used to measure D concentration profiles up to a depth of 7.7 ?m. Thermal desorption spectroscopy (TDS) was used to determine the D retained throughout the bulk of the sample. Isotope exchange allows for a unique study of atomic migration by separately examining the diffusion of implanted atoms from those bombarding the surface. D atoms are exchanged out of traps as a result of H plasma bombardment and diffuse until either falling into another trap or reaching the surface to recombine and escape. Radiation damage at levels of 0.01, 0.1, and 1 displacements per atom (dpa) was carried out before plasma exposure on some samples with 2 MeV Cu ions as a surrogate for damage caused by fusion neutrons. The Cu ion damage was compared to damage induced by 6 MeV W ions to see if there is an effect of Cu contamination on retention. We saw little difference in Cu versus W ion damage at low dpa, but at 1 dpa, where Cu content reached 65 appm, contamination seems to be significant. Retention measurements showed that ion damage has little effectiveness on isotope removal at these sample temperatures; however, there is evidence to suggest that the trapping mechanisms in W change as damage is increased.

Barton, J. L.; Wang, Y. Q.; Dittmar, T.; Doerner, R. P.; Tynan, G. R.

2014-08-01

295

The effects of a single bout of exercise on resting energy expenditure and respiratory exchange ratio.  

PubMed

We investigated the effects of a single bout of aerobic and resistance exercise of similar relative intensity and duration on resting energy expenditure (REE) and substrate utilisation. Ten young healthy males volunteered [age 22 (1.8) years, weight 76 (7.9) kg, height 176 (4.1) cm, percentage body fat 10.5 (4.0)%; mean (SEM)]. They randomly underwent three conditions in which they either lifted weights for 60 min at 70-75% of 1-RM (WL), ran for 60 min at 70-75% of maximal oxygen intake (R) or did not exercise (C). REE and substrate utilisation, determined via respiratory exchange ratio ( R), were measured prior to exercise, and 10, 24, 48 and 72 h post-exercise. It was revealed that REE was significantly elevated ( P<0.05) 10 and 24 h after the end of WL [2,124 (78) and 2,081 (76) kcal, respectively] compared to pre-exercise [1,972 (82) kcal]. REE was also significantly increased ( P<0.05) 10 and 48 h after the completion of R [2,150 (73) and 1,995 (74) kcal, respectively] compared to pre-exercise data [1,862 (70) kcal]. R was lower 10 and 24 h following either WL or R [0.813 (0.043); 0.843 (0.040) and 0.818 (0.021); 0.832 (0.021), respectively] compared to baseline measurements [0.870 (0.025) and 0.876 (0.04), respectively]. Creatine kinase was significantly elevated ( P<0.05) 24 h after both WL and R, whereas delayed onset muscle soreness became significantly elevated ( P<0.05) 24 h after only WL. There were no significant changes for any treatment in thyroid hormones (T(3) and T(4)). These results suggest that a single bout of either WL or R exercise, characterised by the same relative intensity and duration, increase REE and fat oxidation for at least 24 h post-exercise. PMID:15205961

Jamurtas, A Z; Koutedakis, Y; Paschalis, V; Tofas, T; Yfanti, C; Tsiokanos, A; Koukoulis, G; Kouretas, D; Loupos, D

2004-08-01

296

Energy efficient reconcentration of diluted human urine using ion exchange membranes in bioelectrochemical systems.  

PubMed

Nutrients can be recovered from source separated human urine; however, nutrient reconcentration (i.e., volume reduction of collected urine) requires energy-intensive treatment processes, making it practically difficult to utilize human urine. In this study, energy-efficient nutrient reconcentration was demonstrated using ion exchange membranes (IEMs) in a microbial electrolysis cell (MEC) where substrate oxidation at the MEC anode provides energy for the separation of nutrient ions (e.g., NH4(+), HPO4(2-)). The rate of nutrient separation was magnified with increasing number of IEM pairs and electric voltage application (Eap). Ammonia and phosphate were reconcentrated from diluted human urine by a factor of up to 4.5 and 3.0, respectively (Eap = 1.2 V; 3-IEM pairs). The concentrating factor increased with increasing degrees of volume reduction, but it remained stationary when the volume ratio between the diluate (urine solution that is diluted in the IEM stack) and concentrate (urine solution that is reconcentrated) was 6 or greater. The energy requirement normalized by the mass of nutrient reconcentrated was 6.48 MJ/kg-N (1.80 kWh/kg-N) and 117.6 MJ/kg-P (32.7 kWh/kg-P). In addition to nutrient separation, the examined MEC reactor with three IEM pairs showed 54% removal of COD (chemical oxygen demand) in 47-hr batch operation. The high sulfate concentration in human urine resulted in substantial growth of both of acetate-oxidizing and H2-oxidizing sulfate reducing bacteria, greatly diminishing the energy recovery and Coulombic efficiency. However, the high microbial activity of sulfate reducing bacteria hardly affected the rate of nutrient reconcentration. With the capability to reconcentrate nutrients at a minimal energy consumption and simultaneous COD removal, the examined bioelectrochemical treatment method with an IEM application has a potential for practical nutrient recovery and sustainable treatment of source-separated human urine. PMID:25046373

Tice, Ryan C; Kim, Younggy

2014-11-01

297

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

298

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

299

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

300

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

301

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

302

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

EPA Science Inventory

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

303

Conceptual study of in-tank cesium removal using an inorganic ion exchange material  

SciTech Connect

Presently, the Hanford Site contains approximately 230,000 m{sup 3} of mixed waste stored in 177 underground tanks. Approximately 55,000 m{sup 3} of this waste is sludge, 90,000 m{sup 3} is salt cake, and 80,000 m{sup 3} is supernate. Although the pretreatment and final disposal requirements for the waste have not been entirely defined, it is likely that some supernatant pretreatment will be required to remove {sup 137}Cs and possibly {sup 90}Sr and the transuranic components. The objective of this study was to estimate the number of HLW glass canisters resulting from the use of inorganic ion exchanger materials as in-tank pretreatment technology. The variables in the study were: number of contacts between waste and ion exchange material; ion exchange material; and decontamination requirement. This conceptual study investigates a generic in-tank Cs removal flowsheet using crystalline silico-titanates and IE-96 zeolites, and the impact of each ion exchanger on the number of glass canisters produced. In determining glass formulation, data based on current reference technology was used. Sample calculations from the worksheets and summaries of final calculated results are included at the end of this report.

Goheen, R.S.; Kurath, D.E.

1996-04-01

304

The development and characterization of ion exchange membranes for selected electrochemical power sources  

NASA Astrophysics Data System (ADS)

The work is reviewed on the development and characterization of ion exchange membranes in an effort to improve the efficiency of three flowing electrolyte batteries. The batteries are: (1) NASA's iron chromium redox battery; (2) Lockheed's zinc ferricyanide battery; and (3) Johnson Control's zinc bromine battery. These batteries were developed for solar photovoltaic, utility load leveling, and electric vehicle applications, respectively.

Arnold, C., Jr.; Assink, R. A.

305

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

SciTech Connect

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

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

1993-03-01

306

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

SciTech Connect

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

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

1993-03-01

307

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

E-print Network

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

Kaganovich, Igor

308

Synthesis of Anomeric Methyl Fructofuranosides and Their Separation on an Ion-Exchange Resin  

ERIC Educational Resources Information Center

Treatment of d-fructose with methanol in the presence of acid as a catalyst gives a mixture of methyl-[beta]-d-fructopyranoside, methyl-[alpha]-D-fructofuranoside, and methyl-[beta]-d-fructofuranoside, which were separated on an ion exchange column and characterized polarimetrically.

Nurminen, Erkki; Poijarvi, Paivi; Koskua, Katja; Hovinen, Jari

2007-01-01

309

ARSENIC REMOVAL FROM DRINKING WATER BY ION EXCHANGE AND ACTIVATED ALUMINA PLANTS  

EPA Science Inventory

This report documents a long term performance study of two ion exchange (IE) and two activated alumina (AA) treatment plants to remove arsenic from drinking water. Performance information was collected on these systems that are located in the northeast for one full year. The stud...

310

A radiochemical study of the kinetics of ion exchange on hydrous titanium dioxide  

Microsoft Academic Search

This paper reports a radiochemical study of the kinetics of ion exchange of Na+ and Cs+ with H+ on hydrous titanium dioxide. The experimental conditions are set to favor the particle diffusion mechanism only, and this is confirmed by the Bt versus t plots. On the basis of these studies the various physical parameters such as the effective diffusion coefficients,

I. M. El-Naggar; M. A. El-Absy

1992-01-01

311

Ion exchange kinetics of cesium for various reaction designs using crystalline silicotitanate, UOP IONSIV IE911  

Microsoft Academic Search

Through collaborative efforts at Texas A&M University and Sandia National Laboratories, a crystalline silicotitanate (CST), which shows extremely high selectivity for radioactive cesium removal in highly concentrated sodium solutions, was synthesized. The effect of hydrogen peroxide on a CST under cesium ion exchange conditions has been investigated. The experimental results with hydrogen peroxide showed that the distribution coefficient of cesium

Sung Hyun Kim

2003-01-01

312

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

SciTech Connect

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

Hang, T.

2002-03-07

313

High Level Waste System Impacts from Small Column Ion Exchange Implementation  

Microsoft Academic Search

The objective of this task is to identify potential waste streams that could be treated with the Small Column Ion Exchange (SCIX) and perform an initial assessment of the impact of doing so on the High-Level Waste (HLW) system. Design of the SCIX system has been performed as a backup technology for decontamination of High-Level Waste (HLW) at the Savannah

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

2005-01-01

314

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

Microsoft Academic Search

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

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

2003-01-01

315

Hb H Interference on Measurement Of HbA1c With Ion-Exchange HPLC.  

PubMed

In this article, an interference caused by hemoglobin H (Hb H), during the measurement of hemoglobin A1c (HbA1c) with ion exchange high pressure liquid chromatography (HPLC) method, was presented in blood sample of a 20-year-old male patient. HbA1c measurement was performed with Agilent 1200 HPLC system using a commercial Recipe HbA1c ion-exchange column. Hemoglobin electrophoresis was performed with Interlab G26 agarose electrophoresis automated compact system. HbA1c level was 18.2% and HbA0 level was 81.5% with ion-exchange HPLC method. Patient's fasting serum glucose was assessed before HbA1c measurement and the result was 165 mg/dL (9.16 mmol/L). On the other hand, the result of HbA0 was 87.9%, Hb H was 10.8% and Hb A2 was 1.3% with electrophoresis. Whole blood test values were within reference ranges except MCV. MCV value was 79.6 fL. It is important to keep in mind that HbA1c level might be considered falsely high with ion-exchange HPLC method because of Hb H containing sample. PMID:24167397

Agilli, Mehmet; Yaman, Halil; Aydinl, Fevzi Nuri; Cayci, Tuncer; Sener, Irfan

2013-01-01

316

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

E-print Network

restricting specific flow of heat energy to the coolant - water - does not allow to cool pipes surface.N.Gumilyov Eurasian National University, Pushkin str.11,01008 Astana, Kazakhstan. Department of Heat-energy, L of the material balance equation, the equation of the kinetics of ion exchange for the nonequilibrium case

317

Incorporation of phthalocyanines by cationic and anionic clays via ion exchange and direct synthesis  

Microsoft Academic Search

Phthalocyanines (Pc) and metallophthalocyanines were incorporated into the galleries of anionic and cationic clays via ion exchange and in situ crystallization of the synthetic clay layers. Intercalation compounds between the layered magnesium silicate clay hectorite and cationic phthalocyanines were directly prepared by refluxing for 2 days aqueous solutions of silica sol, magnesium hydroxide, lithium flouride, and either alcian blue dyes

K. A. Carrado; R. E. Botto; R. E. Winans; J. E. Forman

1993-01-01

318

EVALUATION OF ION EXCHANGE SOFTENING ON THE LEACHING OF METALS FROM HOUSEHOLD PLUMBING SYSTEMS  

EPA Science Inventory

A 16 month pilot plant study was conducted to determine the effect of ion exchange softening on the leaching of metals from household plumbing materials. wo pipe loop pilot plant systems were assembled. ach system consisted of duplicate loops of lead pipe, copper pipe with 50:50 ...

319

ANNUAL REPORT. NEW METAL NIOBATE AND SILICOTITANATE ION EXCHANGERS: DEVELOPMENT AND CHARACTERIZATION  

EPA Science Inventory

This project focuses on the synthesis and characterization of silicotitanate- and niobate-based ion exchangers for Cs and Sr removal and their related condensed phases as potential ceramic waste forms, as well as on understanding the structural property relationship and thermodyn...

320

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

Microsoft Academic Search

A procedure for the simultaneous extraction of phosphorus, potassium, calcium and magnesium from soils, by an ion?exchange resin procedure applicable to large?scale advisory soil testing, is described. The important steps are the disaggregation of soil by shaking in water during 15 minutes with a glass marble, the transference of the elements from the soil to a sodium bicarbonate treated mixture

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

1986-01-01

321

Copper doping of silicate glasses by the ion-exchange technique: A photoluminescence spectroscopy study  

NASA Astrophysics Data System (ADS)

Copper-alkali ion exchange is used for doping superficial layers of different silicate glasses (commercial soda-lime and BK7) with copper ions. Spectroscopic and time-resolved photoluminescence properties of the obtained systems are studied in the range of 80-294 K. Analysis indicates the presence of Cu+ ions located in distorted octahedral sites, and a different position of the triplet electronic levels for the two glass matrices. The luminescence decay-time signal is simulated by a biexponential behavior, interpreted on the basis of a four-level scheme.

Borsella, E.; Dal Vecchio, A.; Garc?Ì?a, M. A.; Sada, C.; Gonella, F.; Polloni, R.; Quaranta, A.; van Wilderen, L. J. G. W.

2002-01-01

322

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

PubMed

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

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

2008-01-28

323

Basis document for PFP plutonium nitrate ion exchange process in Room 228A  

SciTech Connect

The PFP facility currently has approximately 4300 liters of plutonium nitrate solution in storage. This material will be calcined by the Vertical Denigration Calciner (VDC) located in room 230C. However, part of the material needs to be purified to remove constituents that will interfere with the calcination process. An Ion Exchange process using Reillex{trademark} HPQ anion exchange resin was tested by the Plutonium Process Support Laboratories (PPSL) (I). The Ion exchange process is to be installed in glovebox HC-7 in room 228A/234-5Z. The plutonium separated from the interfering constituents will be in a concentrated condition ready to be calcined by the VDC in room 230C. The oxide product of the VDC will be placed into the 2736-Z vaults for long term storage.

Risenmay, H.R.

1997-04-23

324

Atomic hydrogen escape rate due to charge exchange with hot plasmaspheric ions  

NASA Technical Reports Server (NTRS)

Data on ion and electron temperatures and concentrations to several thousand kilometers of altitude were obtained from the Atmosphere Explorer C satellite for 1974 and to 850 km from Arecibo incoherent scatter radar measurements. These data were used to normalize diffusive equilibrium profiles. From these profiles and by using the neutral atmospheric model of Jacchia (1971) and a new hydrogen model, the charge-exchange-induced neutral hydrogen escape fluxes for equatorial and middle latitudes were calculated. The data confirm earlier estimates that the charge exchange loss is more important than Jeans escape for the earth. It is also found that inside the plasmapause this charge exchange process with hot plasmapheric ions is the major production and loss process for the satellite population in the hydrogen geocorona.

Maher, L. J.; Tinsley, B. A.

1977-01-01

325

Ion Exchange Equilibrium and Kinetic Properties of Polyacrylate Films and Applications to Chemical Analysis and Environmental Decontamination  

NASA Technical Reports Server (NTRS)

One of the goals of the original proposal was to study how cross-linking affects the properties of an ion exchange material(IEM) developed at Lewis Research Center. However, prior to the start of this work, other workers at LERC investigated the effect of cross-linking on the properties of this material. Other than variation in the ion exchange capacity, the chemical characteristics were shown to be independent of the cross-linking agent, and the degree of cross-linking. New physical forms of the film were developed (film, supported film, various sizes of beads, and powder). All showed similar properties with respect to ion exchange equilibria but the kinetics of ion exchange depended on the surface area per unit mass; the powder form of the IEM exchanging much more rapidly than the other forms. The research performed under this grant was directed towards the application of the IEM to the analysis of metal ions at environmental concentrations.

Tanner, Stephen P.

1997-01-01

326

A method for controlling the activities of free metal, hydrogen, and phosphate ions in hydroponic solutions using ion exchange and chelating resins  

Microsoft Academic Search

Summary  An ion exchange and chelating resin system was developed to buffer the activities of selected free cations and phosphate in\\u000a hydroponic solutions at concentrations similar to those that occur naturally in soil solutions. Free-ion activities of Cd,\\u000a Cu, Ni, Zn, Mn, H, Ca, Mg, and K were maintained by ion exchange and chelating resins in a controlled ionic strength system.

R. T. Checkai; L. L. Hendrickson; R. B. Corey; P. A. Helmke

1987-01-01

327

Contact Activation of Blood Plasma and Factor XII by Ion-exchange Resins  

PubMed Central

Sepharose ion-exchange particles bearing strong Lewis acid/base functional groups (sulfopropyl, carboxymethyl, quarternary ammonium, dimethyl aminoethyl, and iminodiacetic acid) exhibiting high plasma protein adsorbent capacities are shown to be more efficient activators of blood factor XII in neat-buffer solution than either hydrophilic clean-glass particles or hydrophobic octyl sepharose particles ( FXII?surfaceactivatorFXIIa; a.k.a autoactivation, where FXII is the zymogen and FXIIa is a procoagulant protease). In sharp contrast to the clean-glass standard of comparison, ion-exchange activators are shown to be inefficient activators of blood plasma coagulation. These contrasting activation properties are proposed to be due to the moderating effect of plasma-protein adsorption on plasma coagulation. Efficient adsorption of blood plasma proteins unrelated to the coagulation cascade impedes FXII contacts with ion-exchange particles immersed in plasma, reducing autoactivation, and causing sluggish plasma coagulation. By contrast, plasma proteins do not adsorb to hydrophilic clean glass and efficient autoactivation leads directly to efficient activation of plasma coagulation. It is also shown that competitive-protein adsorption can displace FXIIa adsorbed to the surface of ion-exchange resins. As a consequence of highly-efficient autoactivation and FXIIa displacement by plasma proteins, ion-exchange particles are slightly more efficient activators of plasma coagulation than hydrophobic octyl sepharose particles that do not bear strong Lewis acid/base surface functionalities but to which plasma proteins adsorb efficiently. Plasma proteins thus play a dual role in moderating contact activation of the plasma coagulation cascade. The principal role is impeding FXII contact with activating surfaces but this same effect can displace FXIIa from an activating surface into solution where the protease can potentiate subsequent steps of the plasma coagulation cascade. PMID:21982294

Yeh, Chyi-Huey Josh; Dimachkie, Ziad O.; Golas, Avantika; Cheng, Alice; Parhi, Purnendu; Vogler, Erwin A.

2011-01-01

328

Chaotic behavior of ion exchange phenomena in polymer gel electrolytes through irradiated polymeric membrane  

E-print Network

A desktop experiment has been done to show the nonlinearity in the I-V characteristics of an ion conducting electrochemical micro-system. Its chaotic dynamics is being reported for the first time which has been captured by an electronic circuit. Polyvinylidene fluoride-co-hexafluoropropene (PVdF-HFP) gel electrolyte comprising of a combination of plasticizers (ethylene carbonate and propylene carbonate) and salts have been prepared to study the exchange of ions through porous poly ethylene terephthalate (PET) membranes. The nonlinearity of this system is due to the ion exchange of the polymer gel electrolytes (PGEs) through a porous membrane. The different regimes of spiking and non-spiking chaotic motions are being presented. The possible applications are highlighted.

Sangeeta Rawat; Barnamala Saha; Awadhesh Prasad; Amita Chandra

2012-04-18

329

Chaotic behavior of ion exchange phenomena in polymer gel electrolytes through irradiated polymeric membrane  

NASA Astrophysics Data System (ADS)

A desktop experiment has been done to show the nonlinearity in the I-V characteristics of an ion conducting electrochemical micro-system. Its chaotic dynamics is being reported for the first time which has been captured by an electronic circuit. Polyvinylidene fluoride-co-hexafluoropropene (PVdF-HFP) gel electrolyte comprising of a combination of plasticizers (ethylene carbonate and propylene carbonate) and salts have been prepared to study the exchange of ions through porous polyethylene terephthalate (PET) membranes. The nonlinearity of this system is due to the ion exchange of the polymer gel electrolytes (PGEs) through a porous membrane. The different regimes of spiking and non-spiking chaotic motions are being presented. The possible applications are highlighted.

Rawat, Sangeeta; Saha, Barnamala; Prasad, Awadhesh; Chandra, Amita

2012-05-01

330

Magnetic properties of the molecular nanomagnet Cr7Cd: single ion and exchange anisotropy effects.  

PubMed

In order to verify two microscopic models of the molecular nanomagnet Cr7Cd we analyze a number of thermodynamic quantities calculated for two sets of parameters. The first model, with only single ion anisotropy, was established on the basis of the thermodynamic properties (by fitting susceptibility and magnetization) whereas the second, with single ion and bond-dependent exchange anisotropies, was based on the inelastic neutron scattering and EPR spectra. The calculations are performed by means of non-perturbative, numerically exact quantum transfer matrix technique on large scale parallel computers. We demonstrate that the predictions of the models are consistent in the region of small magnetic fields which do not exceed 10 T and differ significantly in higher fields. Comparison with the experiment leads to a conclusion that better modeling of magnetic torque requires more complex microscopic model with single ion and bond-dependent exchange anisotropies. PMID:22400319

Koz?owski, P; Kamieniarz, G

2011-10-01

331

Propagation of charge-exchange plasma produced by an ion thruster  

NASA Technical Reports Server (NTRS)

Under the proper conditions there is an end-effect of a long, cylindrical Langmuir probe which allows a significant increase in collected ion current when the probe is aligned with a flowing plasma. This effect was used to determine the charge-exchange plasma flow direction at various locations relative to the ion thruster. The ion current collected by the probe as a function of its angle with respect to the plasma flow allows determination of the plasma density and plasma flow velocity at the probe's location upstream of the ion thruster optics. The density values obtained from the ion current agreed to within a factor of two of density values obtained by typical voltage-current Langmuir probe characteristics.

Carruth, M. R., Jr.; Brady, M. E.

1981-01-01

332

Synthesis and Characterization of Templated Ion Exchange Resins for the Selective Complexation of Actinide Ions  

SciTech Connect

The purpose of this research is to develop a polymeric extractant for the selective complexation of uranyl ions (and subsequently other actinyl and actinide ions) from aqueous solutions (lakes, streams, waste tanks and even body fluids). Chemical insights into what makes a good complexation site will be used to synthesize reagents tailor-made for the complexation of uranyl and other actinide ions. These insights, derived from studies of molecular recognition include ion coordination number and geometry, ionic size and ionic shape, as well as ion to ligand thermodynamic affinity. Selectivity for a specific actinide ion will be obtained by providing the polymers with cavities lined with complexing ligands so arranged as to match the charge, coordination number, coordination geometry, and size of the actinide metal ion. These cavity-containing polymers will be produced by using a specific ion (or surrogate) as a template around which monomeric complexing ligands will be polymerized. The complexing ligands will be ones containing functional groups known to form stable complexes with a specific ion and less stable complexes with other cations. Prior investigator's approaches for making templated resins for metal ions have had marginal success. We have extended and amended these methodologies in our work with Pb(II) and uranyl ion, by changing the order of the steps, by the inclusion of sonication, by using higher complex loading, and the selection of functional groups with better complexation constants. This has resulted in significant improvements to selectivity. The unusual shape of the uranyl ion suggests that this approach will result in even greater selectivities than already observed for Pb(II). Preliminary data obtained for uranyl templated polymers shows unprecedented selectivity and has resulted in the first ion selective electrode for uranyl ion.

Murray, George M.; Uy, O. Manual murragm1@aplcomm.jhuapl.edu; uyom1@aplmsg.jhuapl.edu

2001-03-01

333

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

PubMed

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

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

2007-09-14

334

One-step refolding and purification of recombinant human tumor necrosis factor-? (rhTNF-?) using ion-exchange chromatography.  

PubMed

Protein refolding is a key step for the production of recombinant proteins, especially at large scales, and usually their yields are very low. Chromatographic-based protein refolding techniques have proven to be superior to conventional dilution refolding methods. High refolding yield can be achieved using these methods compared with dilution refolding of proteins. In this work, recombinant human tumor necrosis factor-? (rhTNF-?) from inclusion bodies expressed in Escherichia coli was renatured with simultaneous purification by ion exchange chromatography with a DEAE Sepharose FF column. Several chromatographic parameters influencing the refolding yield of the denatured/reduced rhTNF-?, such as the urea concentration, pH value and concentration ratio of glutathione/oxidized glutathione in the mobile phase, were investigated in detail. Under optimal conditions, rhTNF-? can be renatured and purified simultaneously within 30 min by one step. Specific bioactivity of 2.18?×?10(8) IU/mg, purity of 95.2% and mass recovery of 76.8% of refolded rhTNF-? were achieved. Compared with the usual dilution method, the ion exchange chromatography method developed here is simple and more effective for rhTNF-? refolding in terms of specific bioactivity and mass recovery. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24941919

Wang, Yan; Ren, Wenxuan; Gao, Dong; Wang, Lili; Yang, Ying; Bai, Quan

2015-02-01

335

Preparation of Ion Exchange Films for Solid-Phase Spectrophotometry and Solid-Phase Fluorometry  

NASA Technical Reports Server (NTRS)

Atomic spectroscopy has dominated the field of trace inorganic analysis because of its high sensitivity and selectivity. The advantages gained by the atomic spectroscopies come with the disadvantage of expensive and often complicated instrumentation. Solid-phase spectroscopy, in which the analyte is preconcentrated on a solid medium followed by conventional spectrophotometry or fluorometry, requires less expensive instrumentation and has considerable sensitivity and selectivity. The sensitivity gains come from preconcentration and the use of chromophore (or fluorophore) developers and the selectivity is achieved by use of ion exchange conditions that favor the analyte in combination with speciative chromophores. Little work has been done to optimize the ion exchange medium (IEM) associated with these techniques. In this report we present a method for making ion exchange polymer films, which considerably simplify the solid-phase spectroscopic techniques. The polymer consists of formaldehyde-crosslinked polyvinyl alcohol with polyacrylic acid entrapped therein. The films are a carboxylate weak cation exchanger in the calcium form. They are mechanically sturdy and optically transparent in the ultraviolet and visible portion of the spectrum, which makes them suitable for spectrophotometry and fluorometry.

Hill, Carol M.; Street, Kenneth W.; Tanner, Stephen P.; Philipp, Warren H.

2000-01-01

336

Characterization of Aluminosilicate Formation on the Surface of a Crystalline Silicotitanate Ion Exchanger  

SciTech Connect

Millions of gallons of high-level radioactive waste are contained in underground tanks at U.S. Department of Energy sites such as Hanford and Savannah River. Most of the radioactivity is due to 137Cs and 90Sr, which must be extracted in order to concentrate the waste. An ion exchanger, crystalline silicotitanate IONSIV IE911, is being considered for separation for Cs at the Savannah River Site (SRS). While the performance of this ion exchanger has been well characterized under normal operating conditions, Cs removal at slightly elevated temperatures, such as those that may occur in a process upset, is not clear. Our recent study indicates that during exposure to SRS simulant at 55 degrees Celsius and 80 degrees Celsius, an aluminosilicate coating formed on the exchanger surface. There was concern that the coating would affect its ion exchange properties. A LEO 982 field emission scanning electron microscope (FESEM) and an Oxford ISIS energy dispersive x-ray spectrometer (EDS) were used to characterize the coating.

Young, James S.; Su, Yali; Li, Liyu; Balmer, M Lou; G W Bailey

2001-10-30

337

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

PubMed

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

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

2014-03-01

338

Application of immobilized metal ion chelate complexes as pseudocation exchange adsorbents for protein separation.  

PubMed

The interactions of horse muscle myoglobin (MYO), tuna heart cytochrome c (CYT), and hen egg white lysozyme (LYS) with three different immobilized metal ion affinity (IMAC) adsorbents involving the chelated complexes of the hard Lewis metal ions Al3+, Ca2+, Fe3+, and Yb3+ and the borderline Lewis metal ion Cu2+ have been investigated in the presence of low- and high-ionic strength buffers and at two different pH values. In contrast to the selectivity behavior noted with buffers of high ionic strength, with low-ionic strength buffers, these three proteins interact with the hard metal ion IMAC adsorbents in a manner more characteristic of cation exchange behavior, although in contrast to the cation exchange chromatography of these proteins, as the pH value of the elution buffer was increased, the retention also increased. The selectivity differences observed under these conditions appear to be due to the formation of hydrolytic complexes of these immobilized metal ion chelate systems involving a change in the coordination geometry of the im-M(n+)-chelate at higher pH values. The experimental observations have been evaluated in terms of the effective charge on the immobilized metal ion chelate complex and the charge characteristics of the specific proteins. PMID:8555175

Zachariou, M; Hearn, M T

1996-01-01

339

Tracing isospin with the {pi}{sup -}/{pi}{sup +} ratio in central heavy ion collisions  

SciTech Connect

Within an isospin- and momentum-dependent hadronic transport model, we have investigated the isospin mixing with the probe of the {pi}{sup -}/{pi}{sup +} ratio in central isospin asymmetric {sup 96}Ru+{sup 96}Zr collision at an incident energy of 400 MeV/u. The isospin equilibrium is not reached according to the asymmetrical distribution of the {pi}{sup -}/{pi}{sup +} ratio with rapidity. In comparison with the nucleon observable, it suggests that the pion ratio {pi}{sup -}/{pi}{sup +} is a promising observable to probe the relaxation of isospin degree of freedom in central heavy ion collisions without being strongly affected by the surface effect. Because of the small system size and rather strong effect of rescattering on pions, the isospin mixing shows insignificant dependence on the stiffness of the symmetry energy in the relevant colliding system.

Zhang Ming; Xiao Zhigang; Zhu Shengjiang [Department of Physics, Tsinghua University, Beijing 100084 (China)

2010-10-15

340

Magnetization reversal and enhanced tunnel magnetoresistance ratio in perpendicular magnetic tunnel junctions based on exchange spring electrodes  

NASA Astrophysics Data System (ADS)

The [Co/Pt]n multilayer based perpendicular magnetic tunnel junction stacks with wedged Co60Fe20B20 insertions up to 2 nm, and corresponding perpendicular magnetic tunnel junctions were magnetically and electrically investigated. The focus is on the influence of CoFeB insertions in the free and reference electrodes on the overall junction magnetization reversal and magnetoresistance response. The exchange spring behavior was revealed as the Co60Fe20B20 spins canting towards the in-plane direction in the [Co/Pt]n/Co60Fe20B20 hard/soft perpendicular magnetic electrodes. The broad range thickness of wedged Co60Fe20B20 insertion enables to reveal the critical transition, in particular, from rigid coupling to exchange spring coupling. With the help of 375°C annealing under 10 kOe magnetic field, the recovery from distinct multi-domain structure to nearly single domain structure was distinctly observed in the unpatterned perpendicular magnetic tunnel junction (p-MTJ) films with CoFeB thickness tCFB?1.5 nm. Meanwhile, for the corresponding patterned perpendicular magnetic tunnel junctions with AlOx barrier, the tunnel magnetoresistance (TMR) ratio exhibited an intense enhancement over 100%. The TMR results and spin configurations were illustrated using an exchange spring model in both magnetic electrodes. The presented study shows the benefit of using exchange spring magnetic electrodes in perpendicular magnetic tunnel junction on their performance.

Wang, Yi; Yin, Xiaolu; Le Roy, D.; Jiang, Jun; Wei, H. X.; Liou, S. H.; Han, X. F.

2013-04-01

341

Monodisperse porous polymer particles with polyionic ligands for ion exchange separation of proteins.  

PubMed

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 microm 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 hydroxyl functionalized beads were treated with 3-(trimethoxysilyl)propyl methacrylate to have covalently linked methacrylate groups on the particle surface. The selected monomers carrying weak or strong ionizable groups (2-acrylamido-2-methyl-1-propane sulfonic acid, AMPS; 2-dimethylaminoethylmethacrylate, DMAEM and N-[3-(dimethylamino)propyl] methacrylamide, DMAPM) were subsequently grafted onto the particles via immobilized methacrylate groups. The final polymer based materials with polyionic ligands were tried as chromatographic packing in the separation of proteins by ion exchange chromatography. The proteins were successfully separated both in the anion and cation exchange mode with higher column yields with respect to the previously proposed materials. The plate heights obtained for poly(AMPS) and poly(DMAEM) grafted poly(DHPM-co-EDM) particles by using proteins as the analytes were 80 and 200 microm, respectively. Additionally, the plate height exhibited no significant increase with the increasing linear flow rate in the range of 1-20 cm/min. The most important property of the proposed strategy is to be applicable for the synthesis of any type of ion exchanger both in the strong and weak form. PMID:17723405

Unsal, Ender; Irmak, Ta?kin; Durusoy, Elifnaz; Tuncel, Mürvet; Tuncel, Ali

2006-06-16

342

Environmentally benign hardness removal using ion-exchange fibers and snowmelt.  

PubMed

Many industrial unit operations and unit processes require near-complete removal of hardness to avoid scaling in heat-transfer equipment, fouling in membranes, and high consumption of detergents and sequestering chemicals in cooling and wash water. Lime softening and cation exchange are the most commonly used processes practiced to date for hardness removal. Herein, we report and discuss the results and attributes of a new hardness removal process using ion-exchange fibers (IX-fibers). Most importantly, the process uses harvested snowmelt (or rainwater) as the regenerant chemical along with sparged carbon dioxide. Consequently, the spent regenerant does not contain a high concentration of aggressive chemicals such as sodium chloride or acid like traditional ion-exchange processes nor does the process produce voluminous sludges similar to lime softening. The bulk of carbon dioxide consumed during regeneration remains sequestered in the aqueous phase as alkalinity. IX-fibers form the heart of the process. They are essentially thin cylindrical polymeric strands 10-20 microm in diameter. The weak-acid carboxylate functional groups reside near to the surface of these cylindrical fibers. Low intraparticle diffusional resistance is the underlying reason IX-fibers are amenable to efficient regeneration with snowmelt sparged with carbon dioxide. When the carbon dioxide partial pressure is increased to 6.8 atm, over 90% calcium desorption efficiency is obtained. On the contrary, commercial weak-acid ion-exchange resins in spherical bead forms are ineffective for regeneration with carbon-dioxide-sparged snowmelt due to extremely slow ion-exchange kinetics involving counter-transport of Ca2+ and H+. PMID:16433374

Greenleaf, John E; Sengupta, Arup K

2006-01-01

343

X-ray Signature of Charge Exchange in the Spectra of L-shell Iron Ions  

SciTech Connect

The X-ray signature of charge exchange between highly charged L-shell iron ions and neutral gas atoms was studied in the laboratory in order to assess its diagnostic utility. Significant differences with spectra formed by electron-impact excitation were observed. In particular, a strong enhancement was found of the emission corresponding to n {le} 4 {yields} n = 2 transitions relative to the n = 3 {yields} n = 2 emission. This enhancement was detectable even with relatively low-resolution X-ray instrumentation (E/{Delta}E {approx} 10) and may enable future identification of charge exchange as a line-formation mechanism in astrophysical spectra.

Beiersdorfer, P; Schweikhard, L; Liebisch, P; Brown, G V

2007-01-05

344

Removal of catalyst in polybutene production by treatment with ion exchange resin  

SciTech Connect

The development of process technology for removal of AlCl/sub 3/ from the reaction mass obtained in the polymerization of butenes by treatment with ion exchange resins is reported. This work also investigated certain reactions that take place in this treatment. It is proposed that the polymerized product should be treated with KU-2-8 cation exchange resin in the H form. The study demonstrates that by the use of resin treatment of the polymerized product that has been prehomogenized with alcohols, it becomes possible to produce low molecular weight polybutenes in a low waste process.

Vlasov, A.V.; Prokof'ev, K.V.; Sangalov, Yu.A.; Kotov, S.V.

1988-09-01

345

Association Mining System for Financial Ratios and Stock Prices in China and Hong Kong Stock Exchange  

Microsoft Academic Search

The focus of this paper is to extract association rules for financial ratios against stock price change. A data mining application\\u000a for association rules on China and Hong Kong Stock Market has been built and to be accessed through the WEB. Preprocessing\\u000a has been done to convert the data on financial report to financial ratios to allow for direct comparison.

Man-chung Chan; H. C. Leung; W. D. Luo

2005-01-01

346

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

PubMed

Ion chromatography as we know it today was built on a foundation of knowledge accumulated over a period of many years. Here, we review some of the outstanding earlier achievements in ion-exchange chromatography. Beginning about 1947. Spedding and Powell at Iowa State published a series of papers describing practical methods for preparative separation of the rare earths by displacement ion-exchange chromatography. The same group then demonstrated the ion-exchange separation of 14N and 15N isotopes in ammonia. Beginning in the 1950s. Kraus and Nelson at Oak Ridge published numerous analytical methods for metal ions based on separation of their chloride, fluoride, nitrate or sulfate complexes by anion chromatography. In the period from about 1960 to 1980 many clever chromatographic methods for metal ion separations were reported by researchers throughout the world and automatic in-line detection was gradually introduced. A truly innovative method by Small, Stevens and Bauman at Dow Chemical Co. marked the birth of modern ion chromatography. Anions, as well as cations, could now be separated quickly and conveniently by a system of suppressed conductivity detection. A method for anion chromatography with non-suppressed conductivity detection was published by Gjerde et al. in 1979. This was followed by a similar method for cation chromatography in 1980. Ion chromatography as we know it today did not just happen. It was built on a solid foundation of knowledge that has accumulated over a period of many years. Revisiting the older ion-exchange chromatography serves not only to pay tribute to some remarkable accomplishments, but it can also be a learning experience. Trends and ideas in science tend to run in repeating cycles. Thus, an awareness of older work may provide inspiration for new research using improved contemporary technology. Selection of milestones is a rather personal matter. I chose to write about subjects of which I came to have a firsthand knowledge during my career. The topics selected are in roughly chronological order and cover the period from about 1945 to 1980. An effort has been made to explain the chemical principles as well as to recount the major accomplishments of the various research projects. PMID:15250395

Fritz, James S

2004-06-11

347

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

SciTech Connect

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

King, W

2007-11-30

348

Inference of the ring current ion composition by means of charge exchange decay  

NASA Technical Reports Server (NTRS)

The analysis of the measured ion fluxes during the several day storm recovery period and the assumption that beside hydrogen other ions were present and that the decays were exponential in nature, it was possible to establish three separate lifetimes for the ions. These fitted decay lifetimes are in excellent agreement with the expected charge exchange decay lifetimes for H(+), O(+), and He(+) in the energy and L-value range of the data. This inference technique, thus, establishes the presence of measurable and appreciable quantities of oxygen and helium ions as well as protons in the storm-time ring current. Indications that He(+) may also be present under these same conditions were found.

Smith, P. H.; Bewtra, N. K.; Hoffman, R. A.

1978-01-01

349

Charge-exchange recombination spectroscopy of the plasma ion temperature at the T-10 tokamak  

SciTech Connect

Charge-exchange recombination spectroscopy (CXRS) based on a diagnostic neutral beam has been developed at the T-10 tokamak. The diagnostics allows one to measure the ion temperature profile in the cross section of the plasma column. In T-10 experiments, the measurement technique was adjusted and the elements of the CXRS diagnostics for ITER were tested. The used spectroscopic equipment makes it possible to reliably determine the ion temperature from the Doppler broadening of impurity lines (helium, carbon), as well as of the spectral lines of the working gas. The profiles of the plasma ion temperature in deuterium and helium discharges were measured at different plasma currents and densities, including with the use of active Doppler measurements of lines of different elements. The validity and reliability of ion temperature measurements performed by means of the developed CXRS diagnostics are analyzed.

Krupin, V. A., E-mail: vkrupin@nfi.kiae.ru [National Research Centre Kurchatov Institute (Russian Federation); Tugarinov, S. N. [Project Center ITER (Russian Federation)] [Project Center ITER (Russian Federation); Barsukov, A. G.; Dnestrovskij, A. Yu.; Klyuchnikov, L. A.; Korobov, K. V.; Krasnyanskii, S. A. [National Research Centre Kurchatov Institute (Russian Federation)] [National Research Centre Kurchatov Institute (Russian Federation); Naumenko, N. N. [National Academy of Sciences of Belarus, Stepanov Institute of Physics (Belarus)] [National Academy of Sciences of Belarus, Stepanov Institute of Physics (Belarus); Nemets, A. R.; Sushkov, A. V.; Tilinin, G. N. [National Research Centre Kurchatov Institute (Russian Federation)] [National Research Centre Kurchatov Institute (Russian Federation)

2013-08-15

350

Comparison of ion exchange and cw CO 2 laser treatment of Nd-doped phosphate laser glass  

NASA Astrophysics Data System (ADS)

We investigate the relation of ion-exchange treatment and laser conditioning of a glass surface. The surface of Nd-doped phosphate laser glass was preirradiated with a cw CO 2 laser and strengthened by the ion-exchange treatment. It is shown that residual compressive stress occurs on the surface as peak-to-valley roughness and the appearance of microcracks decreases. Damage threshold of the glass surface increases by a factor of 1.7 3. The mechanism of laser conditioning is consistent with that of the ion-exchange treatment.

Gong, Hui; Li, Chengfu

1997-07-01

351

Two Ions Simultaneously Trapped to Measure the Antiproton Charge-to-Mass Ratio  

NASA Astrophysics Data System (ADS)

The antiproton (barp) and proton (php) charge-to-mass ratios are improved by an order of magnitude(G. Gabrielse, D. Phillips, W. Quint, H. Kalinowsky, G. Rouleau, W. Jhe, Phys. Rev. Lett. 77), 3544 (1995).. A single php, dressed with two electrons to form the negative hydrogen ion (H^-), is simultaneously trapped with a single barp in a Penning Trap. With the barp excited into a large cyclotron orbit, the eigenfrequencies of the centered H^- are measured. Next, roles are reversed and the eigenfrequencies of the centered barp are measured. After including the well known proton-to-electron mass ratio and the H^- binding energy, the H^- and barp frequency comparison determines the ratio of (q/m) for the antiproton/proton. The biggest systematic of the previous measurement is eliminated since we compare particles of the same sign of charge, and the time between measurements is shorter. This measurement is among the most accurate mass spectroscopy measurements made, is the first precise measurement made with two ions trapped at the same time, and confirms most accurately that CPT holds for protons.

Khabbaz, A.; Hall, D. S.; Gabrielse, G.; Heimann, C.; Kalinowsky, H.; Jhe, W.

1998-05-01

352

Hydrogen production in the K-Basin ion exchange columns, modules and cartridge filters  

SciTech Connect

K-Basin uses ion exchange modules and ion exchange (IX) columns for removing radionuclides from the basin water. When the columns and modules are loaded, they are removed from service, drained and stored. After a few IX columns accumulate in storage, they are moved to a burial box. One of the burial box contains 33 columns and the other, six. The radionuclides act on the liquid left within and adhering to the beads to produce hydrogen. This report describes the generation rate, accumulation rate and significance of that accumulation. This summary also highlights those major areas of concern to the external (to Westinghouse Hanford Company [WHC]) reviewers. Appendix H presents the comments made by the external reviewers and, on a separate sheet, the responses to those comments. The concerns regarding the details of the analytical approach, are addressed in Appendix H and in the appropriate section.

Not Available

1994-12-21

353

Physicochemical simulation of the ion exchange between humus acids and cations of different valencies  

NASA Astrophysics Data System (ADS)

An approximate calculation was made for the ion exchange of black humic acids and the related fulvic acids with the cations H+, K+, Na+, Ca2+, Mg2+, Zn2+, Mn2+, Cu2+, Fe3+, and Al3+. The calculation was based on the method of physicochemical simulation, the concepts of the chemical potentials of the elements, the experimental study of the equilibriums, and the determination of the activity coefficients of the monoionic forms of humus acids. Because of the presence of different functional groups, humus acids are considered as two-phase systems with specific activity coefficients for the monoionic forms of these acids in each phase. Examples of experimental studies and practical calculations of ion-exchange equilibriums in wide ranges of humus and solution cationic compositions were compared. Although the proposed approaches require perfecting, they can be used for solving practical problems and controlling equilibriums at the experimental stage.

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

2012-12-01

354

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

NASA Astrophysics Data System (ADS)

In this paper, spent ion exchange resin generated from PUSPATI TRIGA reactor (RTP) in Malaysian Nuclear Agency were characterized based on the water content, radionuclide content and radionuclide leachability. The result revealed that the water content in the spent resin is 48%. Gamma spectrometry analysis indicated the presence of 134Cs, 137Cs, 152Eu, 54Mn, 58Co, 60Co and 65Zn. The leachability test shows a small concentrations (<1 Bq/l) of 152Eu and 134Cs were leached out from the spent resin while 60Co activity concentrations slightly exceeded the limit generally used for industrial wastewater i.e. 1 Bq/l. Characterization of spent ion exchange resin sampled from RTP show that this characterization is important as a basis to immobilize this radioactive waste using geopolymer technology.

Wahida, Nurul; Yasir, Muhamad Samudi; Majid, Amran Ab; Wahab, Mohd Abd; Marzukee, Nik; Paulus, Wilfred; Phillip, Esther; Thanaletchumy, Irwan, M. N.

2014-09-01

355

Design and modeling of multimode interference structures made by two step ion exchange in glass  

NASA Astrophysics Data System (ADS)

Design, fabrication and RNF measurement of the optical multi-mode interference power splitter 1 to 2 with graded refractive index is reported. The design was developed by utilizing numerical solutions using the finite difference beam propagation method for operation wavelength 1550 nm. The deposition tests that led to the fabrication of the proposed structures were made after designing the structures. Several samples of optical MMI splitters 1x2 were obtained by Ag+<-->Na+ two step field assisted ion exchange process in molten salt into a new special optical glass substrate for ion exchange technology. The refractive index profile of the channel waveguide was verified by the direct measurement near-filed method by the Refractive Near Field Profilometer.

Barkman, Ond?ej; Je?ábek, Vít?zslav; Prajzler, Václav

2015-01-01

356

Ion exchange of several radionuclides on the hydrous crystalline silicotitanate, UOP IONSIV IE-911  

SciTech Connect

The crystalline silicotitanate, UOP IONSIV IE-911, is a proven material for removing radionuclides from a wide variety of waste streams. It is superior for removing several radionuclides from the highly alkaline solutions typical of DOE wastes. This laboratory previously developed an equilibrium model applicable to complex solutions for IE-910 (the power form of the granular IE-911), and more recently, the authors have developed several single component ion-exchange kinetic models for predicting column breakthrough curves and batch reactor concentration histories. In this paper, the authors model ion-exchange column performance using effective diffusivities determined from batch kinetic experiments. This technique is preferable because the batch experiments are easier, faster, and cheaper to perform than column experiments. They also extend these ideas to multicomponent systems. Finally, they evaluate the ability of the equilibrium model to predict data for IE-911.

Huckman, M.E.; Latheef, I.M.; Anthony, R.G. [Texas A and M Univ., College Station, TX (United States)] [Texas A and M Univ., College Station, TX (United States)

1999-04-01

357

Performance and modeling of cesium ion exchange by ENGI neered form crystalline silicotitanates  

SciTech Connect

TAM-5, a hydrous crystalline silicotitanate (CST) powder developed by Sandia National Laboratories and Texas A&M University, and commercialized by UOP as IONSIV{reg_sign} Ion Exchanger Type IE-910, is a highly selective material for removing cesium and strontium from aqueous radioactive wastes such as those found at the Hanford site in Washington. An engineered form of the material suitable for column ion exchange type operations has been developed and tested. Data relevant to processing radioactive tank wastes including equilibrium distribution coefficients and column testing will be presented. The impact of exposure of the engineered form to chemically aggressive environments such as it might experience during waste processing, and to the less aggressive environments it might experience during post processing storage has been assessed. The thermal stability of the material has also been evaluated. The experimental results have been integrated with an effort to model the material`s equilibrium and kinetic behavior.

Anthony, R.G.; Gu, D.; Huckman, M.; Latheef, I.; Philip, C.V. [Texas A& M Univ., College Station, TX (United States)] [and others

1996-10-01

358

Redox sorption of oxygen on a layered cathode-polarized nanocomposite metal-ion exchanger  

NASA Astrophysics Data System (ADS)

The redox sorption of molecular oxygen from a flow of deionized water onto a cathode-polarized granular layer of nanocomposite copper-ion exchanger is considered. A mathematical description of it in terms of external diffusion is given. In contrast to better-known approaches, conditions are created that are as close as possible to the limiting diffusion current; this effect can be achieved by dividing the granular layer into shallow layers, each of which is then polarized with a near-limiting current. This allows water to be obtained with a particular value of deoxygenation close to the theoretically calculated value in stationary sorption membrane electrolyzers equipped with a unit containing a nanocomposite copper-ion exchanger. It is established that the lower deoxygenation value relative to the one calculated from the limiting current is associated with the additional reduction of oxygen with copper nanoparticles.

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

2012-12-01

359

Charge-exchange erosion studies of accelerator grids in ion thrusters  

NASA Technical Reports Server (NTRS)

A particle simulation model is developed to study the charge-exchange grid erosion in ion thrusters for both ground-based and space-based operations. Because the neutral gas downstream from the accelerator grid is different for space and ground operation conditions, the charge-exchange erosion processes are also different. Based on an assumption of now electric potential hill downstream from the ion thruster, the calculations show that the accelerator grid erosion rate for space-based operating conditions should be significantly less than experimentally observed erosion rates from the ground-based tests conducted at NASA Lewis Research Center (LeRC) and NASA Jet Propulsion Laboratory (JPL). To resolve this erosion issue completely, we believe that it is necessary to accurately measure the entire electric potential field downstream from the thruster.

Peng, Xiaohang; Ruyten, Wilhelmus M.; Keefer, Dennis

1993-01-01

360

The use of histological techniques for the demonstration of ion exchange resins.  

PubMed Central

AIM: To establish the staining characteristics of certain ion exchange resins in histological material, with a view to enabling confident differential identification. METHODS: Various histological staining procedures were applied to selected pathological material and prepared agar blocks containing the cation exchange resin calcium polystyrene sulphonate and the anion exchange resin cholestyramine. RESULTS: Calcium polystyrene sulphonate uniquely stained strongly by a direct Schiff's reagent procedure without any preoxidation and by the Ziehl-Neelsen method. Cholestyramine was negative by the former method but stained strongly with a standard Congo red technique. CONCLUSIONS: These staining results are consistent with the known structure and properties of polystyrene sulphonate and cholestyramine resins. Polystyrene sulphonate resins have the virtually pathognomonic feature of direct Schiff positivity, while morphology, location, and strong non-birefringent Congo red positivity facilitate the identification of cholestyramine. It is possible that the intrinsic staining characteristics of cholestyramine may be lost once it has bound to its target. Images PMID:10674039

Chaplin, A J

1999-01-01

361

Kinetic Electron and Ion Instability of the Lunar Wake Simulated at Physical Mass Ratio  

E-print Network

The solar wind wake behind the moon is studied with 1D electrostatic particle-in-cell (PIC) simulations using a physical ion to electron mass ratio (unlike prior investigations); the simulations also apply more generally to supersonic flow of dense magnetized plasma past non-magnetic objects. A hybrid electrostatic Boltzmann electron treatment is first used to investigate the ion stability in the absence of kinetic electron effects, showing that the ions are two-stream unstable for downstream wake distances (in lunar radii) greater than about three times the solar wind Mach number. Simulations with PIC electrons are then used to show that kinetic electron effects can lead to disruption of the ion streams at least three times closer to the moon than in the hybrid simulations. This disruption occurs as the result of a novel wake phenomenon: the non-linear growth of electron holes spawned from a narrow dimple in the electron velocity distribution. Most of the holes arising from the dimple are small and quickly l...

Haakonsen, Christian Bernt; Zhou, Chuteng

2015-01-01

362

Formation of silver colloids in silver ion-exchanged soda-lime glasses during annealing  

Microsoft Academic Search

The structural and compositional changes of the soda-lime glasses during the formation of the silver colloids were analyzed by the X-ray Photoelectron Spectroscopy (XPS) in order to examine the silver colloid formation mechanism. The in situ behavior of silver and SiO2 networks on the surfaces of silver ion-exchanged soda-lime glasses during heating and cooling processes in ultra-high vaccum was monitored.

Paul W. Wang

1997-01-01

363

Improved and selective platinum recovery from spent ?-alumina supported catalysts using pretreated anionic ion exchange resin  

Microsoft Academic Search

Improved and selective recovery of platinum from a spent dehydrogenation platinum ?-alumina supported catalyst using a strong basic ion exchange resin is reported. Platinum and other precious metal group (PMG) complexes are leached using concentrated hydrochloric acid along with about 0.20vol.% nitric acid as an oxidizing agent from de-coked and crushed spent catalyst. Effects of hydrochloric acid concentration, time, and

K. Shams; F. Goodarzi

2006-01-01

364

Repeated use of ion-exchange resin membranes in calcareous soils  

USGS Publications Warehouse

This study compared the consistency of nutrient extraction among repeated cycles of ion-exchange resin membrane use. Two sandy calcareous soils and different equilibration temperatures were tested. No single nutrient retained consistent values from cycle to cycle in all treatments, although both soil source and temperature conferred some influence. It was concluded that the most conservative use of resin membranes is single-use.

Sherrod, S.K.; Belnap, Jayne; Miller, M.E.

2003-01-01

365

Cesium Removal from Simulated and Actual Hanford Tank Waste Using Ion Exchange  

Microsoft Academic Search

Effective cesium removal from Hanford tank wastes is presented using SuperLig 644, an elutable, organic ion exchanger. Test materials included simulant 241?AW?101, actual wastes from tanks 241?AP?101, 241?AN?102 combined with wash and leachate solutions from 241?C?104 solids, concentrated 241?AZ?102, 241?AZ?101, and 241?AP?104. Multiple process cycle testing was conducted using dual, small columns in series. Cesium (Cs) load and elution profiles

Sandra K. Fiskum; David L. Blanchard; Stuart T. Arm; Reid A. Peterson

2005-01-01

366

Preliminary Ion Exchange Modeling for Removal of Cesium from Hanford Waste Using Hydrous Crystalline Silicotitanate Material  

Microsoft Academic Search

For the current pretreatment facility design of the River Protection Project (RPP) Waste Treatment Plant (WTP), the removal of cesium from low activity waste (LAW) is achieved by ion-exchange technology based on SuperLig(R) 644 resin. Due to recent concerns over potential radiological and chemical degradation of SuperLig(R) 644 resin and increased pressure drops observed during pilot-scale column studies, an increased

LUTHER L

2004-01-01

367

Development and properties of crystalline silicotitanate (CST) ion exchangers for radioactive waste applications  

Microsoft Academic Search

Crystalline silicotitanates (CSTs) are a new class of ion exchangers that were jointly invented by researchers at Sandia National Laboratories and Texas A&M University. One particular CST, known as TAM-5, is remarkable for its ability to separate parts-per-million concentrations of cesium from highly alkaline solutions (pH> 14) containing high sodium concentrations (>5M). It is also highly effective for removing cesium

James E. Miller; Norman E. Brown

1997-01-01

368

Development and properties of crystalline silicotitanate (CST) ion exchangers for radioactive waste applications  

SciTech Connect

Crystalline silicotitanates (CSTs) are a new class of ion exchangers that were jointly invented by researchers at Sandia National Laboratories and Texas A&M University. One particular CST, known as TAM-5, is remarkable for its ability to separate parts-per-million concentrations of cesium from highly alkaline solutions (pH> 14) containing high sodium concentrations (>5M). It is also highly effective for removing cesium from neutral and acidic solutions, and for removing strontium from basic and neutral solutions. Cesium isotopes are fission products that account for a large portion of the radioactivity in waste streams generated during weapons material production. Tests performed at numerous locations with early lab-scale TAM-5 samples established the material as a leading candidate for treating radioactive waste volumes such as those found at the Hanford site in Washington. Thus Sandia developed a Cooperative Research and Development Agreement (CRADA) partnership with UOP, a world leader in developing, commercializing, and supplying adsorbents and associated process technology to commercialize and further develop the material. CSTs are now commercially available from UOP in a powder (UOP IONSIV{reg_sign} IE-910 ion exchanger) and granular form suitable for column ion exchange operations (UOP IONSIV{reg_sign} IE-911 ion exchanger). These materials exhibit a high capacity for cesium in a wide variety of solutions of interest to the Department of Energy, and they are chemically, thermally, and radiation stable. They have performed well in tests at numerous sites with actual radioactive waste solutions, and are being demonstrated in the 100,000 liter Cesium Removal Demonstration taking place at Oak Ridge National Laboratory with Melton Valley Storage Tank waste. It has been estimated that applying CSTs to the Hanford cleanup alone will result in a savings of more than $300 million over baseline technologies.

Miller, J.E.; Brown, N.E.

1997-04-01

369

Pilot-Scale Test of Counter-Current Ion Exchange (CCIX) Using UOP IONSIV IE911  

Microsoft Academic Search

A pilot-scale test of a moving-bed configuration of a UOP IONSIV? IE-911 ion-exchange column was performed over 17 days at Severn Trent Services facilities. The objectives of the test, in order of priority, were to determine if aluminosilicate precipitation caused clumping of IE-911 particles in the column, to observe the effect on aluminum-hydroxide precipitation of water added to a simulant-filled

Dennis W. Wester; Robert K Leugemors; Richard Dennis; Jeff Pike; Paul W. Taylor; Thong Hang

2001-01-01

370

Characterization of Aluminosilicate Formation on the Surface of a Crystalline Silicotitanate Ion Exchanger  

Microsoft Academic Search

Millions of gallons of high-level radioactive waste are contained in underground tanks at U.S. Department of Energy sites such as Hanford and Savannah River. Most of the radioactivity is due to 137Cs and 90Sr, which must be extracted in order to concentrate the waste. An ion exchanger, crystalline silicotitanate IONSIV IE911, is being considered for separation for Cs at the

James S. Young; Yali Su; Liyu Li; M Lou Balmer; G W Bailey

2001-01-01

371

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

SciTech Connect

Bechtel National, Inc. (BNI) is evaluating the alternate Cs ion exchanger, spherical resorcinol-formaldehyde (RF), for use in the River Protection Project-Waste Treatment Plant (RPP-WTP).( ) Previous test activities with spherical RF indicate that it has adequate capacity, selectivity, and kinetics to perform in the plant according to the flowsheet needs. It appears to have better elution and hydraulic properties than the existing alternatives: ground-gel RF and SuperLig® 644 (SL 644).( ) To date, the spherical RF performance testing has been conducted on freshly manufactured resin (within ~2 months of manufacture). The ion exchange resins will be manufactured and shipped to the WTP up to 1 year before being used in the plant. Changes in the resin properties during storage could reduce the capacity of the resin to remove Cs from low-activity waste solutions. Active sites on organic SL-644 resin have been shown to degrade during storage (Arm et al. 2004). Additional testing was needed to study the effects of storage conditions and aging on spherical RF ion exchange performance. Variables that could have a significant impact on ion exchange resins during storage include storage temperature, medium, and time. Battelle—Pacific Northwest Division (PNWD) was contracted to test the effects of various storage conditions on spherical RF resin. Data obtained from the testing will be used by the WTP operations to provide direction for suitable storage conditions and manage the spherical RF resin stock. Storage test conditions included wet and dry resin configurations under nitrogen at three temperatures. Work was initially conducted under contract number 24590-101-TSA-W000-00004 satisfying the needs defined in Appendix C of the Research and Technology Plan( ) TSS A-219 to evaluate the impact of storage conditions on RF resin performance. In February 2007, the contract mechanism was switched to Pacific Northwest National Laboratory (PNNL) Operating Contract DE-AC05-76RL01830.

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

2007-09-10

372

Single-step ion exchange purification of the coagulant protein from Moringa oleifera seed  

Microsoft Academic Search

The coagulant protein from Moringa oleifera (MO) seed was purified using a single-step batch ion exchange (IEX) method. Adsorption and elution parameters were optimized.\\u000a Impact of the purification on the reduction of organic and nutrient release to the water was studied. The matrix was equilibrated\\u000a using ammonium acetate buffer, and the optimum ionic strength of NaCl for elution was 0.6 M.

K. A. Ghebremichael; K. R. Gunaratna; G. Dalhammar

2006-01-01

373

Submicron Ion-Exchange Fibers of Polystyrene and Styrene-Butadiene-Styrene Copolymer Blends  

Microsoft Academic Search

In the present study, submicron ion-exchange fibers (IEF) of polystyrene (PS) and its blends with styrene-butadiene-styrene block copolymer (SBS) were prepared by electrospinning and post-sulfonating modification. Scanning electron microscopy (SEM) images showed that the diameters of the fibers enlarged significantly after treatment and the surfaces become rougher. Mechanical properties analysis showed that the electrospun fibers (EF) and the IEFs from

Shu-Qin Feng; Xin-Yuan Shen; Ya-Li Ji

2011-01-01

374

Ion exchange micro columns for on-line preconcentration of heavy metals  

Microsoft Academic Search

An on-line break-through test for zinc, cadmium and lead has been carried out by means of a flow-through cell and computerized potentiometric stripping analysis. This test has been applied to seventeen ion-exchange materials and enabled within a short time a predecision about the suitability of a resin for a special preconcentration problem. For the determination of the three trace elements

O. Elsholz; G. Schulze

1995-01-01

375

Ion exchange micro columns for on-line preconcentration of heavy metals  

Microsoft Academic Search

An on-line break-through test for zinc, cadmium and lead has been carried out by means of a flow-through cell and computerized potentiometric stripping analysis. This test has been applied to seventeen ion-exchange materials and enabled within a short time a predecision about the suitability of a resin for a special precon-centration problem. For the determination of the three trace elements

O. Elsholz; G. Schulze

1995-01-01

376

Neodymium-doped ion-exchanged waveguide lasers in BK7 glass  

Microsoft Academic Search

The availability of integrated optical sources in glass is expected greatly to enhance optical signal processing in glass substrates. A study of potassium ion-exchanged waveguide lasers in neodymium-doped BK-7 glass substrates is reported. Design parameters for low-threshold waveguide lasers with high slope efficiencies are described, and methods are given for the fabrication of substrates, waveguides and laser cavities. Properties of

Eustace K. Mwarania; Ji Wang; James S. Wilkinson

1993-01-01

377

Preparation of solid polymer electrolyte composites: investigation of the ion-exchange process  

Microsoft Academic Search

The rate of ion-exchange between an aqueous solution of platinum tetramine and a Nafion® 117 membrane in H+ form is studied. Experimental data are collected using extended X-ray absorption fine structure (EXAFS) spectroscopy in dispersive mode. Results are obtained for various platinum tetramine concentrations in the solution and different hydrodynamic regimes at the membrane-solution interface. A shift from a layer

P. Millet; F. Andolfatto; R. Durand

1995-01-01

378

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

E-print Network

advisory committee. The expert assistance of Dr. C. V. Philip is appreciated. I appreciate the financial support received from the Sandia National Laboratories. This research would not have been possible without it. I would like to thank my fellow... silicotitanates ion exchange material, labelled TAM5, invented by Texas A&M University and Sandia National Laboratories can solve the problem of cesium removal from these radioactive liquid wastes. Other materials that have been evaluated by the DOE have either...

Nguyen, Luan Thanh

2012-06-07

379

The load and release characteristics on a strong cationic ion-exchange fiber: kinetics, thermodynamics, and influences  

PubMed Central

Ion-exchange fibers were different from conventional ion-exchange resins in their non-cross-linked structure. The exchange was located on the surface of the framework, and the transport resistance reduced significantly, which might mean that the exchange is controlled by an ionic reaction instead of diffusion. Therefore, this work aimed to investigate the load and release characteristics of five model drugs with the strong cationic ion-exchange fiber ZB-1. Drugs were loaded using a batch process and released in United States Pharmacopoeia (USP) dissolution apparatus 2. Opposing exchange kinetics, suitable for the special structure of the fiber, were developed for describing the exchange process with the help of thermodynamics, which illustrated that the load was controlled by an ionic reaction. The molecular weight was the most important factor to influence the drug load and release rate. Strong alkalinity and rings in the molecular structures made the affinity between the drug and fiber strong, while logP did not cause any profound differences. The drug–fiber complexes exhibited sustained release. Different kinds and concentrations of counter ions or different amounts of drug–fiber complexes in the release medium affected the release behavior, while the pH value was independent of it. The groundwork for in-depth exploration and further application of ion-exchange fibers has been laid. PMID:25114504

Yuan, Jing; Gao, Yanan; Wang, Xinyu; Liu, Hongzhuo; Che, Xin; Xu, Lu; Yang, Yang; Wang, Qifang; Wang, Yan; Li, Sanming

2014-01-01

380

Determination of {sup 16}O and {sup 18}O sensitivity factors and charge-exchange processes in low-energy ion scattering  

SciTech Connect

Quantitative analysis in low-energy ion scattering (LEIS) requires an understanding of the charge-exchange processes to estimate the elemental sensitivity factors. In this work, the neutralization of He{sup +} scattered by {sup 18}O-exchanged silica at energies between 0.6 and 7 keV was studied. The process is dominated by Auger neutralization for E{sub i} < 0.8 keV. An additional mechanism starts above the reionization threshold. This collision-induced neutralization becomes the dominant mechanism for E{sub i} > 2 keV. The ion fractions P{sup +} were determined for Si and O using the characteristic velocity method to quantify the surface density. The {sup 18}O/{sup 16}O sensitivity ratio indicates an 18% higher sensitivity for the heavier O isotope.

Tellez, H.; Chater, R. J.; Fearn, S.; Symianakis, E.; Kilner, J. A. [Department of Materials, Imperial College, SW7 2AZ London (United Kingdom); Brongersma, H. H. [Department of Materials, Imperial College, SW7 2AZ London (United Kingdom); Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

2012-10-08

381

Effects of ion exchange on stream solute fluxes in a basin receiving highway deicing salts  

USGS Publications Warehouse

At Fever Brook, a 1260-ha forested basin in central Massachusetts, highway deicing salt application increased the solute flux in streamflow by 120% above background flux (equivalent basis) during a 2-yr period. Attempts to isolate the nonsalt component of stream solute fluxes have commonly subtracted salt contributions based on the net Cl flux (Cl output in streamflow minus Cl input in precipitation). In these studies, any net Na flux in excess of the amount needed to balance the net Cl flux has been attributed to weathering. At Fever Brook, however, the net output of Na was less than the net output of Cl, suggesting a loss of Na within the basin. The Na sink was inferred to be cation exchange of Na for Ca and Mg in the soil. A method was developed to quantify the exchange based on a Na budget, which included an independent estimate of the Na flux from weathering. The amount of exchange was apportioned to Ca and Mg based on their relative concentrations in the stream. The background fluxes of Ca and Mg (i.e., those that would occur in the absence of deicing salts) were calculated by subtracting the amounts from ion exchange plus the much smaller direct contributions in deicing salts from the observed fluxes. Ion exchange and direct salt contributions increased the net output fluxes of Ca and Mg, each by 44% above background. In basins that receive deicing salts, failure to account for cation exchange thus may result in an underestimate of the flux of Na from weathering and overestimates of the fluxes of Ca and Mg from weathering.

Shanley, J.B.

1994-01-01

382

Synthesis and Thermal Stability of Polycrystalline New Divalent ??- and ?-Ferrites Prepared by Ion Exchange  

NASA Astrophysics Data System (ADS)

Using ion-exchange chemistry the divalent cations Ba 2+, Sr 2+, Ca 2+, Mg 2+ Cd 2+, Pb 2+, Co 2+, Zn 2+, Mn 2+, Fe 2+, and Sn 2+ have been substituted for K + in polycrystalline CdO-stabilized K-??-ferrite samples. Ba, Sr, Ca, Mg, Pb, and Cd ion exchange led to the synthesis of new materials, the divalent M2+ -??-ferrites ( M = Ba, Sr, Ca, Mg) and M2+ -?-ferrites ( M = Cd, Pb), respectively, Co 2+-diffusion resulted in the formation of a spinel-type Co-ferrite. In the case of Zn, Mn, Fe, and Sn the samples decomposed to ?-Fe 2O 3. The thermal stability of the new divalent ??- and ?-ferrites was studied either by high-temperature exchange reactions or by air annealing of the exchanged products. Ba- and Sr-??-ferrites and Pb-?-ferrite converted to M-type hexagonal ferrites with the magnetoplumbite structure. Mg-??-ferrite decomposed to a spinel-type Mg-ferrite, and Ca-??-ferrite and Cd-?-ferrite decomposed to ?-Fe 2O 3. Composition, lattice parameters, SEM photographs, and magnetic properties of the ferrites formed are given. The magnetic susceptibilities of the divalent ??- or ?-ferrites have values between 0.63 and 1.14 × 10 -4 emu/g · Oe at room temperature.

Kalogirou, O.

1993-02-01

383

Effect of ionophores on the rate of intramolecular cation exchange in durosemiquinone ion pairs  

NASA Technical Reports Server (NTRS)

The effects of the ionophores 15-crown-5 (15C5), 18-crown-6 (18C6), dibenzo-18-crown-6 (DBC) and cryptand 222 (C222) on intramolecular cation exchange in ion pairs of the sodium salt of the durosemiquinone anion in benzene solution are investigated. Electron paramagnetic resonance spectra of the 18C6 and 15C5 complexes with durosemiquinone reduced by contact with a sodium mirror show an alternating line width which indicates that the sodium ion is being exchanged between equivalent sites near the oxygens of the semiquinone with activation energies of 8.7 and 6.0 kcal/mole and Arrhenius preexponential factors of 9 x 10 to the 12th/sec and 10 to the 12th/sec, respectively. Spectra obtained for the DBC complexes show no evidence of exchange, while those of C222 indicate rapid exchange. It is also noted that the hyperfine splitting constants measured do not change over the 50-K temperature interval studied.

Eastman, M. P.; Bruno, G. V.; Mcguyer, C. A.; Gutierrez, A. R.; Shannon, J. M.

1979-01-01

384

Solar Wind Charge Exchange Studies Of Highly Charged Ions On Atomic Hydrogen  

NASA Astrophysics Data System (ADS)

Accurate studies of low-energy charge exchange (CX) are critical to understanding underlying soft X-ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H-like, and He-like ions of C, N, O and Ne, which are the dominant charge states for these heavier elements in the solar wind. Absolute total cross sections for single electron capture by H-like ions of C, N, O and fully-stripped O ions from atomic hydrogen have been measured in an expanded range of relative collision energies (5 eV/u-20 keV/u) and compared to previous H-oven measurements. The present measurements are performed using a merged-beams technique with intense highly charged ion beams extracted from a 14.5 GHz ECR ion source installed on a high voltage platform at the Oak Ridge National Laboratory. For the collision energy range of 0.3 keV/u-3.3 keV/u, which corresponds to typical ion velocities in the solar wind, the new measurements are in good agreement with previous H-oven measurements. The experimental results are discussed in detail and compared with theoretical calculations where available.

Dragani?, I. N.; Seely, D. G.; McCammon, D.; Havener, C. C.

2011-06-01

385

TRANSIENT HEAT TRANSFER ANALYSIS FOR ION-EXCHANGE WASTE REMOVAL PROCESS  

SciTech Connect

The small column ion exchange (SCIX) process treats low curie salt (LCS) waste before feeding it to the saltstone facility to be made into grout. Through this process, radioactive cesium from the salt solution is absorbed into the CST bed. A CST column loaded with radioactive cesium will generate significant heat from radiolytic decay. If engineering designs of the CST sorption column can not handle this thermal load, hot spots may develop locally within the column and degrade the performance of the ion-exchange process. The CST starts to degrade at about 80 to 85 C, and the CST completely changes to another material above 120 C. In addition, the process solution will boil around 130 C. If the column boiled dry, the sorbent could plug the column and require replacement of the column module. The objective of the present work is to compute temperature distributions across the column as a function of transit time after the initiation of accidents when there is loss of the salt solution flow in the CST column under abnormal conditions of the process operations. In this situation, the customer requested that the calculations should be conservative in that the model results would show the maximum centerline temperatures achievable by the CST design configurations. The thermal analysis results will be used to evaluate the fluid temperature distributions and the process component temperatures within the ion exchange system. This information will also assist in the system design and maintenance.

Lee, S.

2010-07-12

386

IMPACT OF THE SMALL COLUMN ION EXCHANGE PROCESS ON THE DEFENSE WASTE PROCESSING FACILITY - 12112  

SciTech Connect

The Savannah River Site (SRS) is investigating the deployment of a parallel technology to the Salt Waste Processing Facility (SWPF, presently under construction) to accelerate high activity salt waste processing. The proposed technology combines large waste tank strikes of monosodium titanate (MST) to sorb strontium and actinides with two ion exchange columns packed with crystalline silicotitanate (CST) resin to sorb cesium. The new process was designated Small Column Ion Exchange (SCIX), since the ion exchange columns were sized to fit within a waste storage tank riser. Loaded resins are to be combined with high activity sludge waste and fed to the Defense Waste Processing Facility (DWPF) for incorporation into the current glass waste form. Decontaminated salt solution produced by SCIX will be fed to the SRS Saltstone Facility for on-site immobilization as a grout waste form. Determining the potential impact of SCIX resins on DWPF processing was the basis for this study. Accelerated salt waste treatment is projected to produce a significant savings in the overall life cycle cost of waste treatment at SRS.

Koopman, D.; Lambert, D.; Fox, K.; Stone, M.

2011-11-07

387

Charge exchange spectroscopy system calibration for ion temperature measurement in KSTAR.  

PubMed

The charge exchange spectroscopy (CES) system including collection assemblies, lens design, and cassettes for the KSTAR experiment was installed to obtain profiles of the ion temperature and the toroidal rotation velocity from charge exchange emission between plasma ions and beam neutrals near the plasma axis by using a modulated neutral beam and a background system. We can measure the charge exchange spectra of an impurity line such as the 529 nm line of carbon VI to get ion temperature and rotation profiles in KSTAR. The CES and background systems will have absolute intensity and spectral calibrations using a calibrated source and various spectral lamps. The calibration was done inside the tokamak after all CES systems are installed and the optical systems are slid into the cassettes. This requires that the diagnostic systems are installed near the vacuum vessel inside the cryostat maintaining the superconducting state of the superconducting coils. Repeated spectral calibrations of the spectrometer and charge coupled device for CES will be made in the diagnostic room during the experimental campaign. We show a detailed description of the KSTAR CES system, how to calibrate, and the results of calibration. PMID:21033931

Ko, Won-Ha; Lee, Hyungho; Seo, Dongcheol; Kwon, Myeun

2010-10-01

388

Modeling electrostatic interactions of baculovirus vectors for ion-exchange process development.  

PubMed

Product-related impurities constitute a major burden in the production of recombinant viral vectors for gene therapy and vaccination; it impairs not only the biological efficacy of the preparation but the process yield/productivity. Recombinant baculovirus was used as an enveloped virus model to address this issue. Given that ion-exchange chromatography is a process of choice for purification of viral vectors, the analysis of the electrostatic behavior can be instrumental for the improvement of impurity removal. The main species, product (infective virus particle) and product-derived impurities (dsDNA-, glycoprotein-, and envelope-deprived baculovirus particles), were isolated and correspondent zeta potentials were analyzed through dynamic light scattering. A model of the virus based on the viral components critical for biological function is proposed. The contribution of these viral components to the overall particle electrostatic interaction energy profile (calculated between the particle and a putative ion-exchange surface) was assessed as a function of ionic strength and pH. This resulted in a deterministic tool capable of distinguishing the electrostatic properties of the infective virus particle from the major virus-related impurities. Within an ion-exchange bind-elute process, this knowledge helps narrow the optimization space in early stage process development for viral vectors by predicting the best selectivity conditions. PMID:20444457

Vicente, Tiago; Peixoto, Cristina; Alves, Paula M; Carrondo, Manuel J T

2010-06-11

389

Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification  

PubMed Central

Composites of nanocellulose and the conductive polymer polypyrrole (PPy) are presented as candidates for a new generation of haemodialysis membranes. The composites may combine active ion exchange with passive ultrafiltration, and the large surface area (about 80 m2 g?1) could potentially provide compact dialysers. Herein, the haemocompatibility of the novel membranes and the feasibility of effectively removing small uraemic toxins by potential-controlled ion exchange were studied. The thrombogenic properties of the composites were improved by applying a stable heparin coating. In terms of platelet adhesion and thrombin generation, the composites were comparable with haemocompatible polymer polysulphone, and regarding complement activation, the composites were more biocompatible than commercially available membranes. It was possible to extract phosphate and oxalate ions from solutions with physiological pH and the same tonicity as that of the blood. The exchange capacity of the materials was found to be 600 ± 26 and 706 ± 31 ?mol g?1 in a 0.1 M solution (pH 7.4) and in an isotonic solution of phosphate, respectively. The corresponding values with oxalate were 523 ± 5 in a 0.1 M solution (pH 7.4) and 610 ± 1 ?mol g?1 in an isotonic solution. The heparinized PPy–cellulose composite is consequently a promising haemodialysis material, with respect to both potential-controlled extraction of small uraemic toxins and haemocompatibility. PMID:22298813

Ferraz, Natalia; Carlsson, Daniel O.; Hong, Jaan; Larsson, Rolf; Fellström, Bengt; Nyholm, Leif; Strømme, Maria; Mihranyan, Albert

2012-01-01

390

Core-ion temperature measurement of the ADITYA tokamak using passive charge exchange neutral particle energy analyzer  

NASA Astrophysics Data System (ADS)

Core-ion temperature measurements have been carried out by the energy analysis of passive charge exchange (CX) neutrals escaping out of the ADITYA tokamak plasma (minor radius, a = 25 cm and major radius, R = 75 cm) using a 45° parallel plate electrostatic energy analyzer. The neutral particle analyzer (NPA) uses a gas cell configuration for re-ionizing the CX-neutrals and channel electron multipliers (CEMs) as detectors. Energy calibration of the NPA has been carried out using ion-source and ?E/E of high-energy channel has been found to be ˜10%. Low signal to noise ratio (SNR) due to VUV reflections on the CEMs was identified during the operation of the NPA with ADITYA plasma discharges. This problem was rectified by upgrading the system by incorporating the additional components and arrangements to suppress VUV radiations and improve its VUV rejection capabilities. The noise rejection capability of the NPA was experimentally confirmed using a standard UV-source and also during the plasma discharges to get an adequate SNR (>30) at the energy channels. Core-ion temperature Ti(0) during flattop of the plasma current has been measured to be up to 150 eV during ohmically heated plasma discharges which is nearly 40% of the average core-electron temperature (typically Te(0) ˜ 400 eV). The present paper describes the principle of tokamak ion temperature measurement, NPA's design, development, and calibration along with the modifications carried out for minimizing the interference of plasma radiations in the CX-spectrum. Performance of the NPA during plasma discharges and experimental results on the measurement of ion-temperature have also been reported here.

Pandya, Santosh P.; Ajay, Kumar; Mishra, Priyanka; Dhingra, Rajani D.; Govindarajan, J.

2013-02-01

391

Determination of D / H ratios of nonexchangeable hydrogen in cellulose: A method based on the cellulose-water exchange reaction  

NASA Astrophysics Data System (ADS)

We have established a simple technique for the determination of D/H ratios of nonexchangeable hydrogen in cellulose. This technique is based on equilibrating cellulose prepared from raw wood or cotton with water of known isotopic composition. A temperature of 0°C was selected for the exchange experiments. This allowed the rapid freezing and subsequent sublimation of the ice without affecting the isotopic composition of the equilibrated hydroxyl hydrogen. A sodium hydroxide treatment of the cellulose is necessary to achieve equilibrium between cellulose and water within 24 hours. The best sodium hydroxide treatment procedure was found to be overnight soaking of cellulose in a 17% NaOH solution at near 0°C, followed by rinsing and transferring the cellulose to the exchange vessels without drying. We have obtained a very good reproducibility for the ?D analysis of the equilibrated cellulose treated with this procedure (1? < 2%.). The resulting ?D values of nonexchangeable hydrogen, using the equilibration technique, were compared with those obtained using the nitration technique. The agreement between the two techniques is ±3.3%. (1?), and the analytical accuracy of the equilibration method is ±2.5%. (1?). This method may be useful in dealing with the nitration of ancient plant materials, which is sometimes not possible. In addition, the technique may be extended to the isotopic analysis of other organic compounds that contain exchangeable hydrogen.

Feng, Xiahong; Krishnamurthy, R. V.; Epstein, Samuel

1993-09-01

392

A facile solution approach for the synthesis of akaganéite (?-FeOOH) nanorods and their ion-exchange mechanism toward As(V) ions  

NASA Astrophysics Data System (ADS)

Akaganéite (?-FeOOH) nanorods with a hollandite-type structure were prepared by a simple solution method, and were characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy and nitrogen adsorption-desorption isotherms. The ion-exchange properties of the nanorods toward As(V) ions were investigated. The ion-exchange mechanism between the surface hydroxyl groups and As(V) ions was revealed by FTIR and XPS. From the results of the experiments, it is found that the surface hydroxyl groups which hydrogen bonded water molecules located outside of the hollandite channels play key roles in the ion-exchange process. In addition, the as-prepared ?-FeOOH could be readily regenerated using NaOH solution and be repeatedly used.

Zhang, Yong-Xing; Jia, Yong

2014-01-01

393

Investigation of aspect ratio of hole drilling from micro to nanoscale via focused ion beam fine milling  

E-print Network

Holes with different sizes from microscale to nanoscale were directly fabricated by focused ion beam (FIB) milling in this paper. Maximum aspect ratio of the fabricated holes can be 5:1 for the hole with large size with ...

Fu, Yongqi

394

Rapid preparation of biosorbents with high ion exchange capacity from rice straw and bagasse for removal of heavy metals.  

PubMed

This work describes the preparation of the cellulose phosphate with high ion exchange capacity from rice straw and bagasse for removal of heavy metals. In this study, rice straw and bagasse were modified by the reaction with phosphoric acid in the presence of urea. The introduced phosphoric group is an ion exchangeable site for heavy metal ions. The reaction by microwave heating yielded modified rice straw and modified bagasse with greater ion exchange capacities (?3.62?meq/g) and shorter reaction time (1.5-5.0?min) than the phosphorylation by oil bath heating. Adsorption experiments towards Pb²?, Cd²?, and Cr³? ions of the modified rice straw and the modified bagasse were performed at room temperature (heavy metal concentration 40?ppm, adsorbent 2.0?g/L). The kinetics of adsorption agreed with the pseudo-second-order model. It was shown that the modified rice straw and the modified bagasse could adsorb heavy metal ions faster than the commercial ion exchange resin (Dowax). As a result of Pb²? sorption test, the modified rice straw (RH-NaOH 450W) removed Pb²? much faster in the initial step and reached 92% removal after 20?min, while Dowax (commercial ion exchange resin) took 90?min for the same removal efficiency. PMID:24578651

Rungrodnimitchai, Supitcha

2014-01-01

395

Rapid Preparation of Biosorbents with High Ion Exchange Capacity from Rice Straw and Bagasse for Removal of Heavy Metals  

PubMed Central

This work describes the preparation of the cellulose phosphate with high ion exchange capacity from rice straw and bagasse for removal of heavy metals. In this study, rice straw and bagasse were modified by the reaction with phosphoric acid in the presence of urea. The introduced phosphoric group is an ion exchangeable site for heavy metal ions. The reaction by microwave heating yielded modified rice straw and modified bagasse with greater ion exchange capacities (?3.62?meq/g) and shorter reaction time (1.5–5.0?min) than the phosphorylation by oil bath heating. Adsorption experiments towards Pb2+, Cd2+, and Cr3+ ions of the modified rice straw and the modified bagasse were performed at room temperature (heavy metal concentration 40?ppm, adsorbent 2.0?g/L). The kinetics of adsorption agreed with the pseudo-second-order model. It was shown that the modified rice straw and the modified bagasse could adsorb heavy metal ions faster than the commercial ion exchange resin (Dowax). As a result of Pb2+ sorption test, the modified rice straw (RH-NaOH 450W) removed Pb2+ much faster in the initial step and reached 92% removal after 20?min, while Dowax (commercial ion exchange resin) took 90?min for the same removal efficiency. PMID:24578651

2014-01-01

396

High aspect ratio AFM Probe processing by helium-ion-beam induced deposition.  

PubMed

A Scanning Helium Ion Microscope (SHIM) is a high resolution surface observation instrument similar to a Scanning Electron Microscope (SEM) since both instruments employ finely focused particle beams of ions or electrons [1]. The apparent difference is that SHIMs can be used not only for a sub-nanometer scale resolution microscopic research, but also for the applications of very fine fabrication and direct lithography of surfaces at the nanoscale dimensions. On the other hand, atomic force microscope (AFM) is another type of high resolution microscopy which can measure a three-dimensional surface morphology by tracing a fine probe with a sharp tip apex on a specimen's surface.In order to measure highly uneven and concavo-convex surfaces by AFM, the probe of a high aspect ratio with a sharp tip is much more necessary than the probe of a general quadrangular pyramid shape. In this paper we report the manufacture of the probe tip of the high aspect ratio by ion-beam induced gas deposition using a nanoscale helium ion beam of SHIM.Gas of platinum organic compound was injected into the sample surface neighborhood in the vacuum chamber of SHIM. The decomposition of the gas and the precipitation of the involved metal brought up a platinum nano-object in a pillar shape on the normal commercial AFM probe tip. A SHIM system (Carl Zeiss, Orion Plus) equipped with the gas injection system (OmniProbe, OmniGIS) was used for the research. While the vacuum being kept to work, we injected platinum organic compound ((CH3)3(CH3C5H4)Pt) into the sample neighborhood and irradiated the helium ion beam with the shape of a point on the apex of the AFM probe tip. It is found that we can control the length of the Pt nano-pillar by irradiation time of the helium ion beam. The AFM probe which brought up a Pt nano-pillar is shown in Figure 1. It is revealed that a high-aspect-ratio Pt nano-pillar of ?40nm diameter and up to ?2000 nm length can be grown. In addition, for possible heating by the helium ion beam, it was observed that an original probe shape was transformed. AFM measurement of a reference sample (pitch 100-500 nm, depth 100 nm) of the lines and spaces was performed using the above probes. The conventional probes which did not bring up platinum was not able to get into the ditch enough. Therefore it was found that a salient was big and a reentrant was shallow. On the other hand, the probe which brought up platinum was able to enter enough to the depths of the ditch.jmicro;63/suppl_1/i30-a/DFU075F1F1DFU075F1Fig.1.SHIM image of the AFM probe with the Pt nano-pillar fabricated by ion-beam induced deposition. PMID:25359832

Onishi, Keiko; Guo, Hongxuan; Nagano, Syoko; Fujita, Daisuke

2014-11-01

397

Recovery of gallium(III) from strongly alkaline media using a Kelex-100-loaded ion-exchange resin  

SciTech Connect

Kelex-100 [7-(4-ethyl-1-methyloctyl)-8-hydroxyquinoline] is an important liquid-chelating ion exchanger in hydrometallurgy and a highly selective extractant for gallium (Ga). In this study, Kelex-100-loaded ion-exchange resins were prepared for the recovery of Ga(III) from sodium aluminate solutions (Bayer solution) used in the Bayer process. When macroporous type ion-exchange resins were used as polymer matrices for loading Kelex-100, the physical pore structure and the ion-exchange group significantly affected the adsorption of Ga(III) from strongly alkaline media on the Kelex-100-loaded resin. In particular, the Kelex-100-loaded carboxylic type resin having a macroporous structure showed a high capacity for Ga(III) in concentrated NaOH solution and effectively recovered Ga(III) from the Bayer solution containing large amounts of aluminum(III).

Nakayama, Morio; Egawa, Hiroaki [Kumamoto Univ. (Japan)] [Kumamoto Univ. (Japan)

1997-10-01

398

Analysis of mechanical characteristics of the ionic polymer metal composite (IPMC) actuator using cast ion-exchange film  

NASA Astrophysics Data System (ADS)

IPMC (Ionic Polymer Metal Composite) is a promising candidate actuator for bio-related applications mainly due to its biocompatibility, soft properties and operation in wet condition. The widely used and commercialized ion-exchange polymer film has limitation in thicknesses, but more various film thicknesses are required for extensive applications. Especially for the enhanced force as an actuator, acquisition of thick film is essential. Various ion-exchange polymer films with thickness of 0.4-1.2 mm have been prepared by casting of liquid ion-exchange polymer. As well, IPMC actuators using cast ion-exchange polymer films have been fabricated and the basic mechanical characteristics such as stiffness, displacement and force were measured and analyzed. These results can be used for the optimized design of actuators for different applications.

Kim, Byungkyu; Kim, Byung M.; Ryu, Jaewook; Oh, In-Hwan; Lee, Seung-Ki; Cha, Seung-Eun; Pak, Jungho

2003-07-01

399

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

PubMed

We employ classical and ring polymer molecular dynamics simulations to study the effect of nuclear quantum fluctuations on the structure and the water exchange dynamics of aqueous solutions of lithium and fluoride ions. While we obtain reasonably good agreement with experimental data for solutions of lithium by augmenting the Coulombic interactions between the ion and the water molecules with a standard Lennard-Jones ion-oxygen potential, the same is not true for solutions of fluoride, for which we find that a potential with a softer repulsive wall gives much better agreement. A small degree of destabilization of the first hydration shell is found in quantum simulations of both ions when compared with classical simulations, with the shell becoming less sharply defined and the mean residence time of the water molecules in the shell decreasing. In line with these modest differences, we find that the mechanisms of the exchange processes are unaffected by quantization, so a classical description of these reactions gives qualitatively correct and quantitatively reasonable results. We also find that the quantum effects in solutions of lithium are larger than in solutions of fluoride. This is partly due to the stronger interaction of lithium with water molecules, partly due to the lighter mass of lithium and partly due to competing quantum effects in the hydration of fluoride, which are absent in the hydration of lithium. PMID:25681925

Wilkins, David M; Manolopoulos, David E; Dang, Liem X

2015-02-14

400

A theoretical and numerical study of the use of grid embedded axial magnetic fields to reduce charge exchange ion induced grid erosion in electrostatic ion thrusters  

NASA Astrophysics Data System (ADS)

Decay of ion thruster grids due to impact by charge exchange ions is the main life limiting factor in ion propulsion systems. Any system which can reduce the number or energy of ions impacting the grids will add to the life expectancy at current power levels. One possible technique for reducing damage from charge exchange ions would involve the incorporation in the grids of axial aligned embedded "micro-solenoid" magnetic fields. These fields, generated by currents running around the grid apertures would form mini magnetic nozzles guiding beam ions through the aperture while diverting charge exchange ions from directly impacting the grids. Evaluation of different grid geometries, grid fields, or the use of external or internal auxiliary fields as means to limit charge exchange induced grid erosion is difficult to accomplish either experimentally or computationally. For the sole purpose of quickly testing and evaluating different arrangements of grid geometry and fields a simpler computational model which only evaluates the motion of charge exchange ions would be useful in arriving at a reduced set of potential improved configurations that can then be evaluated by more sophisticated computational and eventually experimental means. A simple computational simulation of the environment within a single set of ion thruster grids has been created for use in evaluating the response of single charge exchange ions to many different grid geometries and field arrangements. This effort involved the development of the ionLite code which simulates the grid geometries, fields, and ion beam charge distribution while allowing individual charge exchange ions to be created at any point and their trajectories and eventual fates to be determined. Using this code the use of auxiliary magnetic fields was examined. This analysis shows that energy transfer to a simulated accelerator grid from charge exchange ions can be reduced by approximately 20%, but only at vary large magnitude magnetic field strengths (order of 100 T). It was found that for the configurations investigated the optimum performance resulted when the applied magnetic field was just enough to cause the particle Larmor radius to be approximately equal to the grid aperture radius. The use of lower mass propellants such as neon or helium allow for this benefit at fields on the order of 20 T. The potential impact of the embedded magnetic fields is shown to be very sensitive to grid geometry, and therefore it is probable that a different configuration could provide even greater reduction in kinetic energy transfer at moderate field levels.

Claypool, Ian R.

401

EXCHANGE  

SciTech Connect

EXCHANGE is published monthly by the Idaho National Engineering Laboratory (INEL), a multidisciplinary facility operated for the US Department of Energy (DOE). The purpose of EXCHANGE is to inform computer users about about recent changes and innovations in both the mainframe and personal computer environments and how these changes can affect work being performed at DOE facilities.

Boltz, J.C. (ed.)

1992-09-01

402

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

E-print Network

ION EXCHANGE COLUMNS FOR SELECTIVE REMOVAL OF CESIUM FROM AQUEOUS RADIOACTIVE WASTE USING HYDROUS CRYSTALLINE SILICO-TITANATES A Thesis by DAVID MICHAEL RICCI Submitted to the Office of Graduate Studies of Texas ARM University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1995 Major Subject: Chemical Engineering ION EXCHANGE COLUMNS FOR SELECTIVE REMOVAL OF CESIUM FROM AQUEOUS RADIOACTIVE WASTE USING HYDROUS CRYSTALLINE SILICO-TITANATES A Thesis...

Ricci, David Michael

2012-06-07

403

Ag +-Na + ion exchange from dilute melt: guidelines for planar waveguide fabrication on a commercial phosphate glass  

NASA Astrophysics Data System (ADS)

Silver-sodium ion-exchanged waveguides on Schott IOG-1 erbium-ytterbium-doped phosphate glass have been fabricated and characterized. Ion exchange by thermal diffusion from a ternary salt melt (AgNO 3, NaNO 3 and KNO 3) has been carried out by varying the process parameters such as melt composition, temperature and diffusion time. Guidelines are given to optimize the active waveguides for a full compatibility with standard single mode optical fibres.

Jose, G.; Sorbello, G.; Taccheo, S.; Della Valle, G.; Cianci, E.; Foglietti, V.; Laporta, P.

2003-09-01

404

Enhancement of the electromechanical behavior of IPMCs based on chitosan\\/polyaniline ion exchange membranes fabricated by freeze-drying  

Microsoft Academic Search

The electromechanical behavior of an ionic polymer-metal composite (IPMC) based on a chitosan\\/polyaniline (CP) interpenetrating polymer network (IPN) is influenced by the internal structure of the CP ion exchange membrane. The freeze-drying method was found to be successful in improving the IPMC electromechanical properties. Scanning electron microscopy (SEM) observations indicated that the ion exchange membranes became more porous after freeze-drying.

Seon Jeong Kim; Min Sup Kim; Su Ryon Shin; In Young Kim; Sun I. Kim; Sang Hoon Lee; Tae Soo Lee; Geoffrey M. Spinks

2005-01-01

405

Temperatures of individual ion species and heating due to charge exchange in the ionosphere of Venus  

NASA Technical Reports Server (NTRS)

The coupled electron and multispecies ion energy equations were solved for daytime conditions in the Venus ionosphere. The heating rates due to charge exchange between hot oxygen atoms and thermal oxygen ions were calculated and incorporated into the energy equations. The combination of the traditional EUV heating and this hot oxygen energy source leads to calculated electron and individual ion temperatures significantly lower than the measured values during solar cycle maximum conditions. Calculations were also carried out for solar cycle minimum conditions, which led to considerably lower temperatures; no data are available which would allow direct comparisons of these results with measurements. In order to obtain calculated temperature values consistent with the observed ones, for solar cycle maximum conditions, topside heat inflows into the ion and electron gases have to be introduced or the thermal conductivity must be reduced by considering the effect of steady and fluctuating magnetic fields, as was done in previous studies. The addition of hot oxygen heating leads to minor increases in the calculated ion temperatures except for the case of reduced thermal conductivities. Separate temperatures were calculated for each ion species for a number of different conditions and in general the differences were found to be relatively small.

Kim, Jhoon; Nagy, Andrew F.; Cravens, Thomas E.; Shinagawa, Hiroyuki

1990-01-01

406

Light-controlled reversible release and uptake of potassium ions from ion-exchanging nanospheres.  

PubMed

Here, we report for the first time on photoswitchable nanospheres containing spiropyran (Sp) for reversible release and uptake of metal ions. K(+) is used as a model ion to demonstrate the chemical principle of this approach. Valinomycin is incorporated in the nanospheres to stabilize K(+). Upon UV illumination, Sp transforms to the more basic ring-opened merocyanine form, which takes up H(+) from the surrounding aqueous solution and expels K(+) from the nanospheres. The process can be reversed by irradiation with visible light to reduce the surrounding K(+) concentration. PMID:24476012

Xie, Xiaojiang; Bakker, Eric

2014-02-26

407

Investigation of platinum(IV) ions sorption on some anion exchangers by using photoacoustic and DRS methods  

Microsoft Academic Search

The high cost and increasing demand have prompted the recovery of platinum from low-grade ores and spent catalysts. Platinum exist in chloride solutions in the anionic form, therefore anion-exchanging is a better method than cation exchanging for sorption of platinum(IV) ions. Therefore applicability of four anion exchangers Duolite A 30 B, Lewatit MP 62, Lewatit MP 64 and Purolite A

G. Wójcik; S. Pasieczna; Z. Hubicki; J. Ryczkowski

2006-01-01

408

Thermodynamic description of the ion exchange and superequivalent sorption of phenylalanine by KU-2-8 cationite  

NASA Astrophysics Data System (ADS)

The coefficients and thermodynamic equilibrium constants, activity coefficients of the sorbent phase, and integral and differential Gibbs energies of the ion-exchange and superequivalent sorption of phenylalanine by strongly acidic KU-2-8 cationites in the H form are calculated using a new thermodynamic approach that allows us to describe the simultaneous exchange and superequivalent sorption of substances by ionites.

Khokhlova, O. N.; Khokhlov, V. Yu.; Trunaeva, E. S.

2015-02-01

409

SEPARATION OF TITANIUM FROM ACCOMPANYING ELEMENTS BY ION-EXCHANGE CHROMATOGRAPHY. 3. SEPARATION OF TITANIUM AND ZIRCONIUM  

Microsoft Academic Search

Distribution coefficients of tetravalent titanium and zirconium between ; ion-exchange resins and hydrochloric acid solutions of various concentrations ; were determined. It was found that there is no sorption of the mentioned ; elements from 0.1 to 6 N hydrochloric acid solutions with anion exchange resins. ; A method was developed for the quantitative chromatographic separation of ; titanium and

T. A. Belyavskaya; I. P. Alimarin; I. F. Kolosova

1958-01-01

410

Synthesis of Single-Crystalline Niobate Nanorods via Ion-Exchange Based on Molten-Salt Reaction  

E-print Network

Synthesis of Single-Crystalline Niobate Nanorods via Ion-Exchange Based on Molten-Salt Reaction by employing hydrothermal reaction2 or templates,3 molten-salt syn- thesis,4 and composite- exchange approach for the synthesis of single-crystal sodium and calcium niobates nanorods based on molten-salt

Wang, Zhong L.

411

Modelling of the oxygen enhancement ratio for ion beam radiation therapy  

NASA Astrophysics Data System (ADS)

The poor treatment prognosis for tumours with oxygen-deficient areas is usually attributed to the increased radioresistance of hypoxic cells. It can be expressed by the oxygen enhancement ratio (OER), which decreases with increasing linear energy transfer (LET) suggesting a potential clinical advantage of high-LET radiotherapy with heavy ion beams compared to low-LET photon or proton irradiation. The aim of this work is to review the experimental cell survival data from the literature and, based on them, to develop a simple OER model to estimate the clinical impact of OER variations. For this purpose, the standard linear-quadratic model and the Alper-Howard-Flanders model are used. According to our calculations for a carbon ion spread-out Bragg peak at clinically relevant intermediate oxygen levels (0.5-20 mmHg), the advantage of carbon ions might be relatively moderate, with OER values about 1%-15% smaller than for protons. Furthermore, the variations of OER with LET are much smaller in vivo than in vitro due to different oxygen partial pressures used in cell experiments or measured inside tumours. The proposed OER model is a simple tool to quantify the oxygen effect in a practical way and provides the possibility to do hypoxia-based biological optimization in treatment planning.

Wenzl, Tatiana; Wilkens, Jan J.

2011-06-01

412

Clinical oxygen enhancement ratio of tumors in carbon ion radiotherapy: the influence of local oxygenation changes.  

PubMed

The effect of carbon ion radiotherapy on hypoxic tumors has recently been questioned because of low linear energy transfer (LET) values in the spread-out Bragg peak (SOBP). The aim of this study was to investigate the role of hypoxia and local oxygenation changes (LOCs) in fractionated carbon ion radiotherapy. Three-dimensional tumors with hypoxic subvolumes were simulated assuming interfraction LOCs. Different fractionations were applied using a clinically relevant treatment plan with a known LET distribution. The surviving fraction was calculated, taking oxygen tension, dose and LET into account, using the repairable-conditionally repairable (RCR) damage model with parameters for human salivary gland tumor cells. The clinical oxygen enhancement ratio (OER) was defined as the ratio of doses required for a tumor control probability of 50% for hypoxic and well-oxygenated tumors. The resulting OER was well above unity for all fractionations. For the hypoxic tumor, the tumor control probability was considerably higher if LOCs were assumed, rather than static oxygenation. The beneficial effect of LOCs increased with the number of fractions. However, for very low fraction doses, the improvement related to LOCs did not compensate for the increase in total dose required for tumor control. In conclusion, our results suggest that hypoxia can influence the outcome of carbon ion radiotherapy because of the non-negligible oxygen effect at the low LETs in the SOBP. However, if LOCs occur, a relatively high level of tumor control probability is achievable with a large range of fractionation schedules for tumors with hypoxic subvolumes, but both hyperfractionation and hypofractionation should be pursued with caution. PMID:24728013

Antonovic, Laura; Lindblom, Emely; Dasu, Alexandru; Bassler, Niels; Furusawa, Yoshiya; Toma-Dasu, Iuliana

2014-09-01

413

Hexavalent chromium [Cr(VI)] removal by the electrochemical ion-exchange process.  

PubMed

In the present investigation, the performance of a laboratory-scale plate and frame-type electrochemical ion-exchange (EIX) cell on removal ofhexavalent chromium from synthetic wastewater containing 5 mg/l of Cr(VI) was evaluated under varying applied voltages. Ruthenium dioxide-coated titanium plate (RuO2/Ti) was used as anode and stainless steel plates as cathode. The EIX cell was run at different hydraulic retention time (HRT). Before using in the electrochemical cell, the capacity of ion-exchange resin was evaluated through kinetic and isotherm equilibrium tests in batch mode. The batch kinetic study result showed that the equilibrium time for effective ion exchange with resin is 2 h. The isotherm equilibrium data fit well to both Freundlich and Langmuir isotherms. Maximum capacity (qm) of resin calculated from Langmuir isotherm was 71.42 mg/g. Up to 99% of chromium removal was noticed in the EIX cell containing fresh resin at applied voltages of 10 V and higher. Migration of chromium ion to anode chamber was not noticed while performing the experiment with fresh resin. As high as 50% removal of chromium was observed from the middle chamber containing exhausted resin at an applied voltage of 25 V when the influent flow rate was maintained at 45 min of HRT. The performance of the reactor was increased to 72% when the influent flow rate was decreased to maintain at 90 min of HRT. Build-up of chromium in the anode chamber took place when exhausted resin was used in the process. PMID:25145180

Dharnaik, Amit Shivputra; Ghosh, Pranab Kumar

2014-01-01

414

Adsorption properties of nitrogen monoxide on silver ion-exchanged zeolites  

SciTech Connect

The removal of nitrogen oxides (NO{sub x}) which cause acid rain and air pollution is an important global environmental problem which needs to be solved soon. The adsorption properties of nitrogen monoxide (NO) on various silver ion-exchanged zeolites were examined by adsorption-desorption measurements in a fixed bed flow apparatus. Both reversible (q{sub rev}) and irreversible (q{sub irr}) adsorption of NO is dependent on the aluminum content in the zeolites and the zeolite structure. The amounts of reversible and irreversible adsorption of NO per silver ion increased with decreasing aluminum content of the zeolites and were constant, independent of the ion exchange level for ZSM-5 zeolites, but increased with the ion exchange level for mordenite zeolites (MOR). It was also found that the adsorption properties are dependent on the temperature and pressure of adsorption: q{sub irr} and q{sub rev} of Ag-MOR increased with decreasing absorption temperature and increasing adsorption pressure. Furthermore, the influence of preadsorbed gases on the Ag-MOR zeolite was investigated, and an enhancement of q{sub rev} was observed when NO{sub 2} was preadsorbed. The NO species adsorbed on the Ag-MOR zeolite were characterized by infrared (IR). Most of the reversibly adsorbed NO species are NO{sup {delta}+} and some N{sub 2}O adsorbed on Ag{sup +}, and the irreversibly adsorbed NO species are some N{sub 2}O, NO{sup {delta}+}, and a small amount of NO{sup {delta}{minus}}, NO{sub 2}{sup {delta}+}.

Zhang, W.; Jia, M.; Yu, J.; Wu, T. [Jilin Univ., Changchun (China). Dept. of Chemistry] [Jilin Univ., Changchun (China). Dept. of Chemistry; Yahiro, Hidenori; Iwamoto, Masakazu [Hokkaido Univ., Sapporo (Japan). Catalysis Research Center] [Hokkaido Univ., Sapporo (Japan). Catalysis Research Center

1999-04-01

415

Selective extraction of metal ions with polymeric extractants by ion exchange/redox  

DOEpatents

The specification discloses a method for the extraction of metal ions having a reduction potential of above about +0.3 from an aqueous solution. The method includes contacting the aqueous solution with a polymeric extractant having primary phosphinic acid groups, secondary phosphine oxide groups, or both phosphinic acid and phosphine oxide groups.

Alexandratos, Spiro D. (Knoxville, TN)

1987-01-01

416

UPTAKE OF METAL IONS BY A NEW CHELATING ION EXCHANGE RESIN. PART 3: PROTONATION CONSTANTS VIA POTENTIOMETRIC TITRATION AND SOLID STATE 31P NMR SPECTROSCOPY  

Microsoft Academic Search

A new chelating ion exchange resin which incorporates methylenediphosphonate, carboxylate, and sulfonate functional groups in a polystyrene-divinylbenzene matrix has been prepared. This resin exhibits exceptionally high affinity for polyvalent cations even from moderately acidic aqueous media. Metal ion coordination occurs primarily at the diphosphonate group with the secondary binding sites contributing to charge neutralization when necessary and possible, and to

K. L. Nash; P. G. Rickert; J. V. Muntean; S. D. Alexandratos

1994-01-01

417

Statistical evaluation of ion-channel gating models based on distributions of log-likelihood ratios.  

PubMed

The distributions of log-likelihood ratios (DeltaLL) obtained from fitting ion-channel dwell-time distributions with nested pairs of gating models (Xi, full model; Xi(R), submodel) were studied both theoretically and using simulated data. When Xi is true, DeltaLL is asymptotically normally distributed with predictable mean and variance that increase linearly with data length (n). When Xi(R) is true and corresponds to a distinct point in full parameter space, DeltaLL is Gamma-distributed (2DeltaLL is chi-square). However, when data generated by an l-component multiexponential distribution are fitted by l+1 components, Xi(R) corresponds to an infinite set of points in parameter space. The distribution of DeltaLL is a mixture of two components, one identically zero, the other approximated by a Gamma-distribution. This empirical distribution of DeltaLL, assuming Xi(R), allows construction of a valid log-likelihood ratio test. The log-likelihood ratio test, the Akaike information criterion, and the Schwarz criterion all produce asymmetrical Type I and II errors and inefficiently recognize Xi, when true, from short datasets. A new decision strategy, which considers both the parameter estimates and DeltaLL, yields more symmetrical errors and a larger discrimination power for small n. These observations are explained by the distributions of DeltaLL when Xi or Xi(R) is true. PMID:16461404

Csanády, László

2006-05-15

418

Evaluation of selected ion exchangers for the removal of cesium from MVST W-25 supernate  

SciTech Connect

The goal of this batch-test equilibration study was to evaluate the effectiveness of certain ion exchangers for removing cesium from supernate taken from tank W-25 of the Melton Valley Storage Tank (MVST) Facility located at the Oak Ridge National Laboratory (ORNL). These exchangers were selective for removing cesium from alkaline supernatant solutions with high salt concentrations. Since the supernates of evaporator concentrates stored in tanks at the MVST facility have compositions similar to some of those stored in tanks at Hanford, the data generated in this study should prove useful in the overall evaluation of the ion exchangers for applications to Hanford and other US Department of Energy (USDOE) sites. A goal of the waste processing effort at Hanford is to remove enough cesium to ensure that the resulting LLW will meet the Nuclear Regulatory Commission (NRC) 10 CFR 61 class A limit for {sup 137}Cs (1 Ci/m{sup 3} or 1 {mu}Ci/mL). The separated cesium may be concentrated and vitrified for disposal in the high-level waste repository. The decontaminated effluent would be solidified for near-surface disposal.

Collins, J.L.; Egan, B.Z.; Anderson, K.K.; Chase, C.W.; Mrochek, J.E.; Bell, J.T.; Jernigan, G.E.

1995-04-01

419

Removal of chromium from electroplating industry effluents by ion exchange resins.  

PubMed

Effluent discharged from the chromium electroplating industry contains a large number of metals, including chromium, copper, nickel, zinc, manganese and lead. The ion exchange process is an alternative technique for application in the treatment of industrial wastewater containing heavy metals and indeed it has proven to be very promising in the removal and recovery of valuable species. The main objective of the present work is to evaluate the performance of commercial ion exchange resins for removing chromium trivalent from industrial effluents, and for this purpose two resins were tested: a chelating exchange resin (Diaion CR11) and a weak cationic resin (Amberlite IRC86). In order to evaluate the sorption capacity of the resins some equilibrium experiments were carried out, being the temperature and pH the main variables considered. The chromium solutions employed in the experiments were synthetic solutions and industrial effluents. In addition, a transient test was also performed as an attempt to understand the kinetic behaviour of the process. PMID:17336455

Cavaco, Sofia A; Fernandes, Sandra; Quina, Margarida M; Ferreira, Licínio M

2007-06-18

420

Kinetic theory and atomic physics corrections for determination of ion velocities from charge-exchange spectroscopy  

NASA Astrophysics Data System (ADS)

Charge-exchange spectroscopy is a powerful diagnostic tool for determining ion temperatures, densities and rotational velocities in tokamak plasmas. This technique depends on detailed understanding of the atomic physics processes that affect the measured apparent velocities with respect to the true ion rotational velocities. These atomic effects are mainly due to energy dependence of the charge-exchange cross-sections, and in the case of poloidal velocities, due to gyro-motion of the ion during the finite lifetime of the excited states. Accurate lifetimes are necessary for correct interpretation of measured poloidal velocities, specially for high density plasma regimes on machines such as ITER, where l-mixing effects must be taken into account. In this work, a full nl-resolved atomic collisional radiative model coupled with a full kinetic calculation that includes the effects of electric and magnetic fields on the ion gyro-motion is presented for the first time. The model directly calculates from atomic physics first principles the excited state lifetimes that are necessary to evaluate the gyro-orbit effects. It is shown that even for low density plasmas where l-mixing effects are unimportant and coronal conditions can be assumed, the nl-resolved model is necessary for an accurate description of the gyro-motion effects to determine poloidal velocities. This solution shows good agreement when compared to three QH-mode shots on DIII-D, which contain a wide range of toroidal velocities and high ion temperatures where greater atomic corrections are needed. The velocities obtained from the model are compared to experimental velocities determined from co- and counter-injection of neutral beams on DIII-D.

Muñoz Burgos, J. M.; Burrell, K. H.; Solomon, W. M.; Grierson, B. A.; Loch, S. D.; Ballance, C. P.; Chrystal, C.

2013-09-01

421

Perchlorate Degradation Using Partially Oxidized Titanium Ions and Ion Exchange Membrane Hybrid System  

E-print Network

3.3.1 Effect of acid type, acid concentration and Ti(0) concentration ....... 33 3.3.2 Further investigation on the effect of Ti(0) and HCl concentration . 45 3.3.3 Effect of F/Ti(0) molar ratio... CHAPTER I INTRODUCTION ................................................................................................ 1 1.1 Statement of Purpose...

Park, Sung Hyuk

2011-08-08

422

The transfer behavior of different ions across anion and cation exchange membranes under vanadium flow battery medium  

NASA Astrophysics Data System (ADS)

The transfer behavior of different ions (V2+, V3+, VO2+, VO2+, H+, SO42-) across ion exchange membranes is investigated under vanadium flow battery (VFB) operating condition. VX-20 anion exchange membrane (AEM) and Nafion 115 cation exchange membrane (CEM) are selected to investigate the influence of fixed charged groups on the transfer behavior of different ions. The interaction between different ions and water is discussed in detail aiming to ascertain the variation of different ions in the charge-discharge process. Under the VFB medium, the transfer behavior and function of different ions are very different for the AEM and CEM. V2+ ions at the negative side accumulate when VFB is assembled with Nafion 115, while the VO2+ ions at the positive side accumulate for VX-20. The SO42- ions will transfer across Nafion 115 to balance the charges and the protons can balance the charges of VX-20. Finally the capacity fade mechanism of different membranes is investigated, showing that the capacity decay of VFB assembled with Nafion 115 mainly results from the cross mix of vanadium ions across the membrane, however, for VX-20, the side reactions can be the major reason. This paper provides important information about electrolyte for the application of VFB.

Sun, Jiawei; Li, Xianfeng; Xi, Xiaoli; Lai, Qinzhi; Liu, Tao; Zhang, Huamin

2014-12-01

423

Ag-doped 45S5 Bioglass®-based bone scaffolds by molten salt ion exchange: processing and characterisation.  

PubMed

There is increasing interest in developing scaffolds with therapeutic and antibacterial potential for bone tissue engineering. Silver is a proven antibacterial agent which bacteria such as MRSA have little or no defense against. Using an ion exchange method, silver ions have been introduced into 45S5 Bioglass(®) based scaffolds that were fabricated using the foam replication technique. This technique allows the introduction of Ag(+) ions onto the surface of the scaffold without compromising the scaffold bioactivity and other physical properties such as porosity. Controlling the amount of Ag(+) ions introduced onto the surface of the scaffold was achieved by tailoring the ion exchange parameters to fabricate samples with repeatable and predictable Ag(+) ion release behavior. In vitro studies in simulated body fluid were carried out to ensure that the scaffolds maintained their bioactivity after the introduction of Ag(+) ions. It was also shown that the addition of low concentrations (2000:1 w/w) of silver ions supported the attachment and viability of human periodontal ligament stromal cells on the 3D scaffolds. This work has thus confirmed ion exchange as an effective technique to introduce Ag(+) ions into 45S5 Bioglass(®) scaffolds without compromising the basic properties of 45S5 Bioglass(®) which are required for applications in bone tissue engineering. PMID:21293911

Newby, P J; El-Gendy, R; Kirkham, J; Yang, X B; Thompson, I D; Boccaccini, A R

2011-03-01

424

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

NASA Astrophysics Data System (ADS)

Heavy ions are more efficient in producing complex-type chromosome exchanges than sparsely ionizing radiation, and this can potentially be used as a biomarker of radiation quality. We measured the induction of complex-type chromosomal aberrations in human peripheral blood lymphocytes exposed in vitro to accelerated H-, He-, C-, Si-, Ar-, Fe- and Au-ions in the LET range 0.4-1400 keV/?m. Chromosomes were observed either at the first post-irradiation mitosis, or in interphase, following premature condensation by phosphatase inhibitors. Selected chromosomes (number 1, 2, 3, 4 or 6) were then visualized after FISH-painting. The dose-response curve for the induction of complex-type exchanges by heavy ions was linear in the dose-range 0.2-1 Gy, while -rays did not produce a significant increase in the yield of complex rearrangements at doses below 2 Gy. The yield of complex aberrations after 1 Gy heavy ions increased up to an LET around 100 keV/?m, and then declined at higher LET values. The frequency of complex rearrangements after 1 Gy was about 10 times higher for Ar- or Si-ions (the most effective ions with LET around 100 keV/?m) than for 250 MeV protons. These results suggest that complex rearrangements may be detected in astronauts' blood lymphocytes after long-term space flights, because crews are exposed to HZE particles from galactic cosmic radiation. However, in a cytogenetic study on six astronauts after long-term missions on the Mir space station, we found a very low frequency of complex rearrangements, and a significant post-flight increase was detected in only one out of six crewmembers. It appears that the use of complex-type exchanges as biomarker of radiation quality in vivo after low-dose chronic exposure in mixed radiation fields is h mpered by statistical uncertainties or possibly the loss ofa heavily damage cells prior to returning to Earth.

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

425

Realization of Ag +/Na + ion-exchanged surface and buried waveguides on germanate glasses  

NASA Astrophysics Data System (ADS)

Ion-exchange technology on glass has been successfully used for more than twenty years to manufacture dependable and low cost integrated optics active and passive devices on silicate or phosphate glasses substrates in the telecommunication wavelengths operation range (from ? = 0.8 to 1.7 ?m). However, the recent developments of integrated optics instruments for astronomical interferometers or biological sensors have lead to an increase of the devices operation range towards the mid-infrared. For these reasons, we present in this paper the realization of both surface and buried waveguides by means of ion-exchange on a glass which is transparent until ? = 5 ?m. In this study, the choice of germanate glass BGA-G115 from Kigre Inc. has been made because of both its similarity with silicate glass, its content of Na + ions and its excellent transparency in the considered operation range. A complete study of the silver ion diffusion on this new glass matrix has been performed allowing the determination of silver and sodium ion-diffusion coefficients at working temperature and silver concentration. Using theses data, simulations have shown that an ion-exchange of 90 min in a 0.03AgNO 3-0.97NaNO 3 molten salt at a temperature of 330°C can lead to the realization of surface single mode channel waveguides at either ? = 1.55 ?m or ? = 3.39 ?m depending on the diffusion window width. To demonstrate channel waveguides on BGA-G115, a specific technological process based on the deposition of a polycrystalline silicon masking layer has been implemented. Single-mode channel waveguides, with a 2.5 ?m diffusion window width, have thus been realized and characterized at the wavelength of 1.55 m. Modal size has been measured to be 10 ?m +/- 1 ?m x 7 ?m +/- 1 ?m for propagation losses of 1.2 dB/cm +/- 0.5 dB/cm for a 2 cm +/- 0.1 cm long device. As for buried waveguides, their feasibility has been demonstrated on multimode ones where a burying depth of 25 ?m +/- 2 ?m has been measured.

Grelin, Jérôme; Ghibaudo, Elise; Broquin, Jean-Emmanuel

2008-02-01

426

Heterogeneity of Ion-Exchange Membranes: The Effects of Membrane Heterogeneity on Transport Properties.  

PubMed

The heterogeneity of different cation-exchange membranes (Neosepta CMX, Selemion CMV, and HJC heterogeneous membrane) and their effects on transport properties were investigated using chronopotentiometry, membrane conductivity, and current-voltage curves. Modifying the classical Sand equation, a method has been developed to determine the fraction of the conducting region (epsilon) of the ion-exchange membrane. The epsilon values of the CMX, CMV, and HJC membranes were 0.93, 0.95, and 0.75, respectively. Considering the characteristics of each membrane-the CMX and CMV are reinforced homogeneous membranes, while the HJC is a heterogeneous membrane-the epsilon values determined in this study seem to be reasonable. The dependence of membrane conductivities and the limiting current densities on the fraction of conducting region of each membrane have also been studied. Copyright 2001 Academic Press. PMID:11502115

Choi, Jae-Hwan; Kim, Sung-Hye; Moon, Seung-Hyeon

2001-09-01

427

An investigation of the radiolytic stability of a resorcinol-formaldehyde ion exchange resin  

SciTech Connect

Developing and demonstrating waste separations technologies are the principal objectives of the Underground Storage Tank -Integrated Demonstration (UST-ID) Program carried out by Pacific Northwest Laboratories (PNL) at the DOE Hanford site. One planned separation technique utilizes ion exchange for removal of cesium and strontium from high-level liquid supernates. A resorcinol-formaldehyde resin, which is a polycondensation-type cation exchange resin for cesium removal, has been developed at the Savannah River Technology Center (SRTC) and has demonstrated superlative performance in testing at SRS, Oak Ridge and PNL. Advantages of this resin relative to other media for cesium removal are its high capacity for cesium and its compatibility with the high pH and aluminum and sodium concentrations of both Hanford and SRS high-level liquid wastes.

Crawford, C.L.; Bibler, N.E.

1994-01-31

428

Processing of Spent Ion Exchange Resins in a Rotary Calciner - 12212  

SciTech Connect

Processing Russian nuclear ion exchange resin KU-2 using a 'Rotary' calciner was conducted. The resulting product is a dry free flowing powder (moisture content 3 wt.%, Angle of repose of ? 20 deg.). Compared with the original exchange resin the volume of the final product is about 3 times less.. Rotary calciner product can be stored in metal drums or in special reinforced concrete cubicles. After thermal treatment in a rotary calciner, the spent resin product can be solidified in cement yielding the following attributes: - The cemented waste is only a 35% increase over the volume of powder product; - The volume of cement calciner product is almost 9 times less (8.7) than the volume of cement solidified resin; - The mechanical strength of cemented calciner product meets the radioactive waste regulations in Russia. (authors)

Kascheev, Vladimir; Musatov, Nikolay [Joint Stock Company 'A.A. Bochvar High-Technology Scientific Research Institute of Inorganic Materials' (VNIINM), Rogova st., 5A (Russian Federation)

2012-07-01

429

Determination of biogenic amines in fish tissues by ion-exchange chromatography with conductivity detection.  

PubMed

Some biogenic amines, such as putrescine, cadaverine, spermidine and histamine, have been found to be useful as quality indices for the decomposition of fish, so research on the simultaneous analysis of various biogenic amines in food is of interest and importance. The intake of histamine may cause an allergic intoxication known as "scombroid poisoning" while secondary biogenic amines can potentiate the toxicity of histamine and in addition can react with nitrite to form carcinogenic nitrosamines. A new method for the simultaneous determination of underivatized biogenic amines based on ion-exchange chromatography with conductivity detector has been developed. The proposed method offers a number of advantages over previous pulsed amperometric detection and integrated pulsed amperometric detection methods such as simpler extraction procedure and sharp peaks. Separations were performed on a new low hydrophobic weak cation-exchange analytical column. This technique is simple, rapid and useful for routine checks in repetitive analyses. PMID:15065779

Cinquina, A L; Calì, A; Longo, F; De Santis, L; Severoni, A; Abballe, F

2004-04-01

430

Synthesis, characterization and analytical application of nano-composite cation-exchange material, poly-o-toluidine Ce(IV) phosphate: Its application in making Cd(II) ion selective membrane electrode  

NASA Astrophysics Data System (ADS)

An organic-inorganic composite, poly-o-toluidine Ce(IV) phosphate was chemically synthesized by mixing ortho-toluidine into the gel of Ce(IV) phosphate in different mixing volume ratios. Effect of eluant concentration, elution behavior and pH-titration studies were carried out to understand the ion-exchange capabilities. The physico-chemical properties of the material were determined using AAS, CHN elemental analysis, UV-VIS spectrophotometry, FTIR, SEM/EDX, TGA-DTA, TEM (Transmission electron microscopy), XRD and SEM studies. The distribution studies revealed that the cation-exchange material is highly selective for Cd(II). Due to selective nature of the cation-exchanger, ion selective membrane electrode was fabricated for the determination of Cd(??) ions in solutions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations.

Khan, Asif Ali; Akhtar, Tabassum

2011-03-01

431

Conductive microtip electrode array with variable aspect ratio using combination process of reactive ion etching  

NASA Astrophysics Data System (ADS)

A micromachining process for a conductive microtip electrode array has been developed using a combination process of reactive ion etching. A localized conical ultra-micro electrode (UME) with submicron width is realized on the tip end for electrochemical measurements. A height of several tens of microns of the silicon microtip is achieved, and the area beyond the UME is covered with dielectric material for electrical insulation. A high-aspect-ratio silicon microtip is fabricated using anisotropic and isotropic etching with varying the gap and diameter of the etch masks. Cyclic voltammetry is conducted to characterize the electrochemical properties of the UMEs. The results indicate that the electrical connection on the UME works successfully, and the measured peak currents were found to be in good agreement with the values estimated from analysis based on conical UME theory.

Ha, Joon-Geun; Lee, Seung-Ki; Bai, Seoung-Jai; Kim, Yong-Kweon; Park, Jae-Hyoung

2013-11-01

432

An evaluation of solution algorithms and numerical approximation methods for modeling an ion exchange process  

SciTech Connect

The focus of this work is on the modeling of an ion exchange process that occurs in drinking water treatment applications. The model formulation consists of a two-scale model in which a set of microscale diffusion equations representing ion exchange resin particles that vary in size and age are coupled through a boundary condition with a macroscopic ordinary differential equation (ODE), which represents the concentration of a species in a well-mixed reactor. We introduce a new age-averaged model (AAM) that averages all ion exchange particle ages for a given size particle to avoid the expensive Monte-Carlo simulation associated with previous modeling applications. We discuss two different numerical schemes to approximate both the original Monte-Carlo algorithm and the new AAM for this two-scale problem. The first scheme is based on the finite element formulation in space coupled with an existing backward difference formula-based ODE solver in time. The second scheme uses an integral equation based Krylov deferred correction (KDC) method and a fast elliptic solver (FES) for the resulting elliptic equations. Numerical results are presented to validate the new AAM algorithm, which is also shown to be more computationally efficient than the original Monte-Carlo algorithm. We also demonstrate that the higher order KDC scheme is more efficient than the traditional finite element solution approach and this advantage becomes increasingly important as the desired accuracy of the solution increases. We also discuss issues of smoothness, which affect the efficiency of the KDC-FES approach, and outline additional algorithmic changes that would further improve the efficiency of these developing methods for a wide range of applications.

Bu Sunyoung [Department of Mathematics, University of North Carolina, Chapel Hill, NC 27599-3250 (United States)], E-mail: agatha@email.unc.edu; Huang Jingfang [Department of Mathematics, University of North Carolina, Chapel Hill, NC 27599-3250 (United States)], E-mail: huang@email.unc.edu; Boyer, Treavor H. [Department of Environmental Engineering Sciences, University of Florida, Gainesville, FL 32611 (United States)], E-mail: thboyer@ufl.edu; Miller, Cass T. [Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599-7431 (United States)], E-mail: caseymiller@unc.edu

2010-07-01

433

An Evaluation of Solution Algorithms and Numerical Approximation Methods for Modeling an Ion Exchange Process.  

PubMed

The focus of this work is on the modeling of an ion exchange process that occurs in drinking water treatment applications. The model formulation consists of a two-scale model in which a set of microscale diffusion equations representing ion exchange resin particles that vary in size and age are coupled through a boundary condition with a macroscopic ordinary differential equation (ODE), which represents the concentration of a species in a well-mixed reactor. We introduce a new age-averaged model (AAM) that averages all ion exchange particle ages for a given size particle to avoid the expensive Monte-Carlo simulation associated with previous modeling applications. We discuss two different numerical schemes to approximate both the original Monte Carlo algorithm and the new AAM for this two-scale problem. The first scheme is based on the finite element formulation in space coupled with an existing backward-difference-formula-based ODE solver in time. The second scheme uses an integral equation based Krylov deferred correction (KDC) method and a fast elliptic solver (FES) for the resulting elliptic equations. Numerical results are presented to validate the new AAM algorithm, which is also shown to be more computationally efficient than the original Monte Carlo algorithm. We also demonstrate that the higher order KDC scheme is more efficient than the traditional finite element solution approach and this advantage becomes increasingly important as the desired accuracy of the solution increases. We also discuss issues of smoothness, which affect the efficiency of the KDC-FES approach, and outline additional algorithmic changes that would further improve the efficiency of these developing methods for a wide range of applications. PMID:20577570

Bu, Sunyoung; Huang, Jingfang; Boyer, Treavor H; Miller, Cass T

2010-07-01

434

Cooperative interactions of metal nanoparticles in the ion-exchange matrix with oxygen dissolved in water  

NASA Astrophysics Data System (ADS)

The kinetics of the reduction of molecular oxygen dissolved in water with nanocomposites consisting of an ion-exchange matrix and copper nanoparticles deposited in it in various amounts was studied. As the metal content in the polymer increased, the amount of reduced oxygen initially increased and then reached the limiting value. At a certain metal content, ionization of individual particles with formation of metal counterions changes to the oxidation of particles assembly giving layers of oxide products. The mechanism changes at the percolation threshold of the electron conductivity of the nanocomposite and determines the maximum amount of absorbed oxygen.

Khorolskaya, S. V.; Polyanskii, L. N.; Kravchenko, T. A.; Konev, D. V.

2014-06-01

435

Laser interferometric measurement of ion electrode shape and charge exchange erosion  

NASA Technical Reports Server (NTRS)

A novel projected fringe profilometry system was applied to surface contour measurements of an accelerator electrode from an ion thruster. The system permitted noncontact, nondestructive evaluation of the fine and gross structure of the electrode. A 3D surface map of a dished electrode was generated without altering the electrode surface. The same system was used to examine charge exchange erosion pits near the periphery of the electrode to determine the depth, location, and volume of material lost. This electro-optical measurement system allowed rapid nondestructive digital data acquisition coupled with automated computer data-processing. In addition, variable sensitivity allowed both coarse and fine measurements of objects having various surface finishes.

Macrae, Gregory S.; Mercer, Carolyn R.

1991-01-01

436

Low-loss, high performance hybrid photonics devices enabled by ion-exchanged glass waveguides  

NASA Astrophysics Data System (ADS)

Robust ion-exchanged glass waveguides exhibit low optical losses in a broad spectral range and they allow integration of several devices on the same chip due to their planar structure. Consequently, they can be a low cost alternative to semiconductors for fabricating various integrated optical devices. Two high performance photonic devices were designed and realized, demonstrating the potential of glass waveguides. The well-controlled silver-film ion-exchange process allowed the fabrication of: i) a highly sensitive biosensor based on optical absorption and, ii) a low loss hybrid electro-optic (EO) polymer modulator with a narrow coplanar electrode gap. The single-mode, channel integrated optical ion-exchange waveguide on borosilicate glass (Corning 0211) is described for broad spectral band (400-650 nm) detection and analysis of heme-containing protein films at a glass/water interface. The evanescent wave interaction is improved significantly by fabricating ion-exchange waveguides with a step-like index profile. Silver nano-particle formation is reduced in order to achieve low loss in the Soret-band (˜400 nm). Unlike other surface-specific techniques (e.g. SPR, interferometry) that probe local refractive-index changes and therefore are susceptible to temperature fluctuations, the integrated optical waveguide absorption technique probes molecular-specific transition bands and is expected to be less vulnerable to environmental perturbations. The hybrid integration of phosphate glass (IOG-1) and EO polymer is realized for the first time. The critical alignment steps which are typically required for hybrid optoelectronic devices are eliminated with a simple alignment-free fabrication technique. The low loss adiabatic transition from glass to EO polymer waveguide is enabled by gray scale patterning of the novel EO polymer, AJLY. Total insertion loss of 5 dB and electrode gap of 8 mum is obtained for an optimized device design. EO polymer poling at 135 °C and 75 V/mum is enabled by the sol-gel buffer layer.

Araci, Ismail Emre

437

Gas generation and bubble formation model for crystalline silicotitanate ion exchange columns  

SciTech Connect

The authors developed a transient model to describe the process of gas generation due to radiolysis and bubble formation in crystalline silicotitanate (CST) ion exchange (IX) columns using the Aspen Custom Modeler (ACM) software package. The model calculates gas concentrations and onset of bubble formation for large CST IX columns. The calculations include cesium loading as a function of time, gas generation as a function of cesium loading, and bubble formation as a function of gas solubility. This report summarizes the model development and predictions.

Hang, T.

2000-07-19

438

Laser interferometric measurement of ion electrode shape and charge exchange erosion  

NASA Technical Reports Server (NTRS)

A projected fringe profilometry system was applied to surface contour measurements of an accelerator electrode from an ion thrustor. The system permitted noncontact, nondestructive evaluation of the fine and gross structure of the electrode. A 3-D surface map of a dished electrode was generated without altering the electrode surface. The same system was used to examine charge exchange erosion pits near the periphery of the electrode to determine the depth, location, and volume of material lost. This electro-optical measurement system allowed rapid, nondestructive, digital data acquisition coupled with automated computer data processing. In addition, variable sensitivity allowed both coarse and fine measurements of objects having various surface finishes.

Macrae, Gregory S.; Mercer, Carolyn R.

1991-01-01

439

Physics and chemistry of antimicrobial behavior of ion-exchanged silver in glass.  

PubMed

The results of a comprehensive study involving the antimicrobial activity in a silver ion-exchanged glass are presented. The study includes the glass composition, the method of incorporating silver into the glass, the effective concentration of the silver available at the glass surface, and the effect of the ambient environment. A quantitative kinetic model that includes the above factors in predicting the antimicrobial activity is proposed. Finally, experimental data demonstrating antibacterial activity against Staphylococcus aureus with correlation to the predicted model is shown. PMID:25562105

Borrelli, N F; Senaratne, W; Wei, Y; Petzold, O

2015-02-01

440

Liquid-Phase Oligomerization of 1Hexene Catalyzed by Macroporous Ion-Exchange Resins  

Microsoft Academic Search

Oligomerization of pure 1-hexene catalyzed by macroporous ion-exchange resins was performed in batch experiments at 350–390 K\\u000a and 2 MPa. At 373 K, after 6 h, 1-hexene conversion was practically complete and the selectivity to dimers was 56%, that to\\u000a trimers 0.8 and 43.2% to double-bond isomerization. By assuming an homogeneous kinetic model for olefin dimerization of second\\u000a order reaction, a value of 64–68 kJ mol?1

Madelin Cadenas; Roger Bringué; Carles Fité; Eliana Ramírez; Fidel Cunill

441

Neutron spectroscopy as a fuel ion ratio diagnostic: Lessons from JET and prospects for ITER  

SciTech Connect

The determination of the fuel ion ratio n{sub t}/n{sub d} in ITER is required at a precision of 20%, time resolution of 100 ms, spatial resolution of a/10, and over a range of 0.01ion temperatures T{sub i}>6 keV and for n{sub T}/n{sub D}<0.6. A crucial issue is the signal-to-background situation in the measurement of the weak 2.5 MeV emission from DD reactions in the presence of a background of scattered 14 MeV DT neutrons. Important experimental input and corroboration for this assessment are presented from the time-of-flight neutron spectrometer at JET where the presence of a strong component of backscattered neutrons is observed. Neutron emission components on ITER due to beam-thermal and tritium-tritium reactions can further enhance the prospects for NES.

Ericsson, G.; Conroy, S.; Gatu Johnson, M.; Andersson Sunden, E.; Cecconello, M.; Eriksson, J.; Hellesen, C.; Sangaroon, S.; Weiszflog, M. [Department of Physics and Astronomy, Uppsala University (EURATOM-VR Association), SE-75120 Uppsala (Sweden); Collaboration: JET EFDA Contributors

2010-10-15

442

Ion-exchange derivatives of Spheron. V. Sulphate and sulpho derivatives.  

PubMed

Using various reactions, strongly acidic derivatives of Spheron of the sulphate and sulpho types were prepared with nominal capacities between 0.37 and 2.0 mequiv./g. They were characterized by their capacities for small ions, by their static and dynamic capacities for proteins, by elemental analysis, by their working volumes and specific internal surface areas. The differences between the nominal capacities calculated theoretically from the sulphur contents and the measured values are discussed, as are the relationships between the nominal capacities for small ions and the static and dynamic capacities for proteins. The chromatographic properties of the cation exchangers are illustrated by the separation of an artificial mixture of proteins (serum albumin, chymotrypsinogen and lysozyme) at various pH values, and of a natural mixture of egg-white proteins. The separation of active enzymes is also reported. Sulphobutyl-Spheron was tested also as a catalyst for the esterification of alcohols. PMID:6548758

Mikes, O; Strop, P; Hostomská, Z; Smrz, M; Slováková, S; Coupek, J

1984-09-28

443

The removal of uranium from acidic media using ion exchange and/or extraction chromatography  

SciTech Connect

The separation and purification of uranium from either nitric acid or hydrochloric acid media can be accomplished by using either solvent extraction or ion-exchange. Over the past two years at Los Alamos, emerging programs are focused on recapturing the expertise required to do limited, small-quantity processing of enriched uranium. During this period of time, we have been investigating ion-addition, waste stream polishing is associated with this effort in order to achieve more complete removal of uranium prior to recycle of the acid. Extraction chromatography has been demonstrated to further polish the uranium from both nitric and hydrochloric acid media thus allowing for a more complete recovery of the actinide material and creation of less waste during the processing steps.

FitzPatrick, J.R.; Schake, B.S.; Murphy, J.; Holmes, K; West, M.H.

1996-06-01

444

Control of interlayer exchange coupling in Fe/Cr/Fe trilayers by ion beam irradiation.  

PubMed

The manipulation of the antiferromagnetic interlayer coupling in epitaxial Fe/Cr/Fe(001) trilayers by 5 keV He ion beam irradiation has been investigated. It is shown that even for irradiation with low fluences a drastic change in strength of the coupling appears. For thin Cr spacers (below 0.6-0.7 nm) it decreases with fluence, becoming ferromagnetic for fluences above 2x10(14) ions/cm(2). The effect is connected with the creation of magnetic bridges in the layered system due to atomic exchange events caused by the bombardment. For thicker Cr spacers an enhancement of the antiferromagnetic coupling strength is found. A possible explanation of the enhancement effect is given. PMID:12689250

Demokritov, S O; Bayer, C; Poppe, S; Rickart, M; Fassbender, J; Hillebrands, B; Kholin, D I; Kreines, N M; Liedke, O M

2003-03-01

445

Cometary X-Rays: Line Emission Cross Sections for Multiply Charged Solar Wind Ion Charge Exchange  

SciTech Connect

Absolute line emission cross sections are presented for 1 keV/amu charge exchange collisions of multiply charged solar wind ions with H{sub 2}O, H, O, CO{sub 2}, and CO cometary targets. The present calculations are contrasted with available laboratory data. A parameter-free model is used to successfully predict the recently observed x-ray spectra of comet C/LINEAR 1999 S4. We show that the resulting spectrum is extremely sensitive to the time variations of the solar wind composition. Our results suggest that orbiting x-ray satellites may be a viable way to predict the solar wind intensities and composition on the Earth many hours before the ions reach the earth.

Otranto, S; Olson, R E; Beiersdorfer, P

2006-12-22

446

Long-range repulsion of colloids driven by ion exchange and diffusiophoresis.  

PubMed

Interactions between surfaces and particles in aqueous suspension are usually limited to distances smaller than 1 ?m. However, in a range of studies from different disciplines, repulsion of particles has been observed over distances of up to hundreds of micrometers, in the absence of any additional external fields. Although a range of hypotheses have been suggested to account for such behavior, the physical mechanisms responsible for the phenomenon still remain unclear. To identify and isolate these mechanisms, we perform detailed experiments on a well-defined experimental system, using a setup that minimizes the effects of gravity and convection. Our experiments clearly indicate that the observed long-range repulsion is driven by a combination of ion exchange, ion diffusion, and diffusiophoresis. We develop a simple model that accounts for our data; this description is expected to be directly applicable to a wide range of systems exhibiting similar long-range forces. PMID:24748113

Florea, Daniel; Musa, Sami; Huyghe, Jacques M R; Wyss, Hans M

2014-05-01

447