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1

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

SciTech Connect

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

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

2007-09-27

2

ION EXCHANGE  

EPA Science Inventory

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

3

Biological Ion Exchanger Resins  

PubMed Central

The cell is presented as a biological ion exchanger resin. The similarities between ion accumulating cells and ion exchanger resins are correlated. The kinetic characteristics of biological ion exchange are shown to be amenable to analysis by a model commonly used for ion exchanger resins. The theories of ion exchange equilibria currently in use with ion exchanger resins are reviewed with their suitability for adaptation to biological ion exchange in mind. ImagesFIGURE 1

Damadian, Raymond

1971-01-01

4

Biological Ion Exchanger Resins  

PubMed Central

Biological selectivity is shown to vary with medium osmotic strength and temperature. Selectivity reversals occur at 4°C and at an external osmolality of 0.800 indicating that intracellular hydration and endosolvent (intracellular water) structure are important determinants in selectivity. Magnetic resonance measurements of line width by steady-state nuclear magnetic resonance (NMR) indicate a difference in the intracellular water signal of 16 Hz between the K form and Na form of Escherichia coli, providing additional evidence that changes in the ionic composition of cells are accompanied by changes in endosolvent structure. The changes were found to be consistent with the thermodynamic and magnetic resonance properties of aqueous electrolyte solutions. Calculation of the dependence of ion-pairing forces on medium dielectric reinforces the role of endosolvent structure in determining ion exchange selectivity.

Damadian, Raymond; Goldsmith, Michael; Zaner, K. S.

1971-01-01

5

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

6

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

7

Ion-exchange hollow fibers  

NASA Technical Reports Server (NTRS)

An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, cross-linked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Klein, Elias (Inventor)

1977-01-01

8

Ion-exchange hollow fibers  

NASA Technical Reports Server (NTRS)

An ion-exchange hollow fiber is prepared by introducing into the wall of the fiber polymerizable liquid monomers, and polymerizing the monomers therein to form solid, insoluble, cross-linked, ion-exchange resin particles which embed in the wall of the fiber. Excess particles blocking the central passage or bore of the fiber are removed by forcing liquid through the fiber. The fibers have high ion-exchange capacity, a practical wall permeability and good mechanical strength even with very thin wall dimensions. Experimental investigation of bundles of ion-exchange hollow fibers attached to a header assembly have shown the fiber to be very efficient in removing counterions from solution.

Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Klein, Elias (Inventor)

1980-01-01

9

Ion exchange - Simulation and experiment  

NASA Technical Reports Server (NTRS)

A FORTRAN program for simulating multicomponent adsorption by ion-exchange resins was adapted for use as both an ASPEN-callable module and as a free-standing simulator of the ion-exchange bed. Four polystyrene-divinylbenzene sulfonic acid resins have been characterized for three principal ions. It is concluded that a chelating resin appears appropriate as a heavy-metal trap. The same ASPEN-callable module is used to model this resin when Wilson parameters can be obtained.

Herrmann, Cal C.; Finn, John E.

1991-01-01

10

Electrically switched cesium ion exchange  

SciTech Connect

Electrically Switched Ion Exchange (ESIX) is a separation technology being developed as an alternative to conventional ion exchange for removing radionuclides from high-level waste. 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 are 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. A case study for the KE Basin on the Hanford Site was conducted based on the results of the development testing. Engineering design baseline parameters for film deposition, film regeneration, cesium loading, and cesium elution were used for developing a conceptual system. Order of magnitude cost estimates were developed to compare with conventional ion exchange. This case study demonstrated that KE Basin wastewater could be processed continuously with minimal secondary waste and reduced associated disposal costs, as well as lower capital and labor expenditures.

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

1997-04-01

11

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

12

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

13

Cesium-specific phenolic ion exchange resin  

DOEpatents

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

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

1995-08-15

14

Electrically Switched Cesium Ion Exchange  

SciTech Connect

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

JPH Sukamto; ML Lilga; RK Orth

1998-10-23

15

Novel silica-based ion exchange resin.  

National Technical Information Service (NTIS)

Eichrom's highly successful Diphonixo resin resembles a conventional ion exchange resin in its use of sulfonic acid ligands on a styrene- divinylbenzene matrix. Diphonix resin exhibits rapid exchange kinetics that allow economical operation of ion exchang...

1997-01-01

16

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

17

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

18

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

19

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

20

Applicability of Simplified Models for the Estimation of Ion Exchange Diffusion Coefficients in Zeolites  

Microsoft Academic Search

The applicability of simplified models for the determination of ion exchange diffusion coefficients in zeolites is examined. The simplified models examined are Vermeulen's, Paterson's, and Nernst–Plank's approximations for isotopic and ion exchange processes, used in ion exchange systems analysis. Parameter analysis indicates the limits for fractional attainment of equilibrium U(t), the ratio of exchangeable ions in liquid to solid phase

Vassilis J. Inglezakis; Helen P. Grigoropoulou

2001-01-01

21

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

22

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

23

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

24

Ion exchange of mixed-alkali glasses  

NASA Astrophysics Data System (ADS)

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

Mattos, Louis, Jr.

1999-11-01

25

Solution Mining Process Using Ion Exchange.  

National Technical Information Service (NTIS)

An exploratory study has been performed on solution mining using ion exchangers to solubilize low grade, inaccessible, or otherwise difficult ores. The scope was to briefly examine this concept with many ores and ion exchangers. The research approach was ...

D. E. Garrett

1978-01-01

26

Method for regenerating ion exchange resin.  

National Technical Information Service (NTIS)

This invention is comprised of a method for regenerating ion exchange resin consisting of a mixed resin containing granular cation exchange resin and anion exchange resin contaminated during condensation treatment in steam power generating plants, charact...

M. Ogihara, K. Ichikawa, T. Idemizu

1991-01-01

27

Pharmaceutical Applications of Ion-Exchange Resins  

Microsoft Academic Search

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

David P. Elder

2005-01-01

28

Radiation effects on ion exchange materials  

Microsoft Academic Search

An extensive literature review and data compilation has been completed on the radiation-damage of ion exchange resins. The primary goal of the study has been to review the available literature on ion exchange materials used in, as well as those with potential for use in, the nuclear fuel and waste reprocessing areas. The physical and chemical properties of ion exchangers

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

1977-01-01

29

Synthesis and ion exchange behaviour of polyaniline Sn(IV) arsenophosphate: a polymeric inorganic ion exchanger  

Microsoft Academic Search

Incorporation of a polymer material into an inorganic ion exchanger provides a class of hybrid ion exchangers with a good ion exchange capacity, high stability, reproducibility and selectivity for heavy metals. Such a type of ion exchanger ‘polyaniline Sn(IV) arsenophosphate’ has been synthesized by mixing polyaniline into inorganic material. This material is characterized using X-ray, IR, TGA studies in addition

Ram Niwas; A. A. Khan; K. G. Varshney

1999-01-01

30

Decomposition of ion exchange resins by pyrolysis  

SciTech Connect

Pyrolysis of spent ion exchange resins is one of the most effective methods for reducing radioactive waster volume and for making the final waste form more stable. Fundamental experiments were performed to clarify the pyrolysis characteristics of anion and cation exchange resins. Residual elemental analyses and off-gas analyses showed that the decomposition ratio of cation resins was only 50 wt% at 600/sup 0/C, while that of anion resins was 90 wt% at 400/sup 0/C. Infrared spectroscopy for cation resins attributed its low decomposition ratio to formation of a highly heat-resistant polymer (sulfur bridged) during pyrolysis. Measurements of residual hygroscopicity and cement package strength indicated that the optimum pyrolysis temperatures for preventing resins swelling and package expansion were between 300 and 500/sup 0/C.

Matsuda, M.; Funabashi, K.; Nishi, T.; Yusa, H.; Kikuchi, M.

1986-11-01

31

A New Method for Studying Kinetics of Ion Exchange with an Ion Exchanger  

Microsoft Academic Search

ESR technique can be used for rate measurement in an ion exchange process, since the signal responds to the presence of paramagnetic ions in the ion exchanger. Employment of this method, which gives continuously the rate curve in situ, is illustrated by an example of measurements on rates of Cu++-Zn++ exchange with polystyrene-sulfonic acid cation exchange resin. The measurements were

Nobufusa Fujita

1966-01-01

32

Development of novel fuel ion ratio diagnostic techniques  

Microsoft Academic Search

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

S. B. Korsholm; M. Stejner; S. Conroy; G. Ericsson; G. Gorini; M. Tardocchi; MG von Hellermann; R. J. E. Jaspers; O. Lischtschenko; EG Delabie; H. Bindslev; V. Furtula; F. Leipold; F. Meo; P. K. Michelsen; D. Moseev; S. K. Nielsen; M. Salewski

2010-01-01

33

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

34

Solidification of ion exchange resin wastes  

SciTech Connect

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

Not Available

1982-08-01

35

Determination of (135)Cs and (135)Cs/(137)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 (t2/1 = 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

36

Ion exchange in the nuclear industry  

SciTech Connect

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

Bibler, J.P.

1990-01-01

37

Ion exchange in the nuclear industry  

SciTech Connect

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

Bibler, J.P.

1990-12-31

38

Rheology of Ion-Exchanged Montmorillonite Clays.  

National Technical Information Service (NTIS)

The Bureau of Mines is investigating a method to dewater fine-particle clay waste. In order to more fully understand the effect of ion exchange on clay dewatering, an investigation of the rheological properties of ion-exchanged montmorillonite was underta...

D. A. Stanley S. W. Webb B. J. Scheiner

1984-01-01

39

Using Ion Exchange Chromatography to Separate Proteins  

NSDL National Science Digital Library

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

Daugherty, Ellyn A.; Exchange, Access E.

40

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

41

Contamination weeping: A chemical ion exchange model  

Microsoft Academic Search

Experiments have been conducted to determine the applicability of a chemical ion-exchange model to characterize the problem of nuclear fuel transportation cask contamination and release ( weeping''). Surface charge characteristics of CrâOâ and stainless steel (304) powders have been measured to determine the potential for ion exchange at metal oxide -- aqueous interfaces. The solubility of pool contaminant Co and

W. B. Chambers; D. H. Doughty; H. D. T. Jones; S. L. Martinez; P. C. Bennett

1991-01-01

42

Ion exchanger from chemically modified banana leaves.  

PubMed

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

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

2013-07-25

43

Ion Exchange of Zeolite Na-Pc with Pb2+, Zn2+, and Ni2+ Ions  

Microsoft Academic Search

This paper examines the ion-exchange properties of synthetic zeolite Na-P0, which was pro- duced from perlite-waste fines and has a SiO2:A1203 ratio of 4.45:1 and a cation-exchange capacity (CEC) of 3.95 meq g ~. Although equilibrium is attained rapidly for all three metals, exchange is incomplete, with At(max) (maximum equilibrium fraction of the metal in the zeolite) being 0.95 for

Aggeliki Moirou; GEORGIOS E. CHRISTIDIS; IOANNIS PASPALIARIS

2000-01-01

44

Electrical Capacitance of Ion-Exchanger Membranes.  

National Technical Information Service (NTIS)

The electrical impedance of ion-exchanger membranes between identical solutions of uni-univalent electrolyte was studied. At subaudio frequencies there was a large capacitance (Farads/sq cm) which varied with frequency, electrolyte concentration, individu...

J. R. Segal

1966-01-01

45

Composite ion exchangers: Prospective nuclear applications  

Microsoft Academic Search

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

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

1994-01-01

46

Porous Ceramic Spheres from Ion Exchange Resin  

NASA Technical Reports Server (NTRS)

A commercial cation ion exchange resin, cross-linked polystyrene, has been successfully used as a template to fabricate 20 to 50 micron porous ceramic spheres. Ion exchange resins have dual template capabilities. Pore architecture of the ceramic spheres can be altered by changing the template pattern. Templating can be achieved by utilizing the internal porous structure or the external surface of the resin beads. Synthesis methods and chemical/physical characteristics of the ceramic spheres will be reported.

Dynys, Fred

2005-01-01

47

CAESIUM-SODIUM ION EXCHANGE ON CLINOPTILOLITE  

Microsoft Academic Search

Clinoptilolite is a natural zeolite that has a high selectivity for Cs. ; The sorption of Cs and Na ions on clinoptilolite is determined, and exchange ; sorption isotherms are determined for Cs-Na exchange on clinoptilolite at 50 and ; 75 deg C. (T.F.H.);

CALEN R. FRYSINGER

1962-01-01

48

INORGANIC ION EXCHANGERS, PAST, PRESENT, AND FUTURE  

Microsoft Academic Search

The search for inorganic ion exchangers that would be stable to ionizing radiation and elevated temperatures began with the advent of nuclear technology in the 1940's. Research has continued unabated since then producing many dozens of such compounds both synthetic and natural. Several of the important groups of these exchangers are described and their utility as highly selective sorbents described.

Abraham Clearfield

2000-01-01

49

SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS XXXIX. SYNTHESIS OF TITANIUM(IV) ANTIMONATES AND THEIR ION EXCHANGE PROPERTIES FOR ALKALI AND ALKALINE EARTH METAL IONS  

Microsoft Academic Search

Titanium antimonate (TiSbA) cation exchanger, prepared under different molar ratios of titanium and antimony, has been characterized by X-ray diffraction, thermal analysis, infrared spectra, and pH-titration. The pH-titration curves showed apparently monobasic acid type. The uptakes of alkali metal ions increased with increasing pH of the solution and with decreasing the molar ratio (Ti\\/Sb) in the exchanger. An unusual selectivity

M. Abe; R. Chitrakar; M. Tsuji; K. Fukumoto

1985-01-01

50

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.

51

Shale oil denitrogenation with ion exchange  

SciTech Connect

The nitrogen-containing aromatics normally found in crude retorted shale oils have been shown to be involved in reactions leading to the deposition of insoluble gums and sediments. These nitrogen-containing compounds must be removed in order to permit the effective utilization of the shale oil product. A process is proposed in which the nitrogen-containing compounds found in raw shale oil are removed by mild hydrodenitrogenation followed by resin ion exchange. Ion exchange data from experimentation involving six jet fuel (154-271C) and diesel fuel (271-343C) boiling point cuts are presented. Amberlyst A-15, a macroreticular, strongly acidic, cation exchange resin is used in this study. Three types of experiments were performed: batch sorption equilibrium experiments, batch sorption kinetics experiments, and dynamic ion-exchange column performance tests. The Langmuir isotherm was found to describe the equilibrium sorption behavior of the shale oil/ion-exchange resin system fairly well. The sorption kinetics are described using a quadratic-driving force model. Dynamic modeling, assuming intraparticle (solid) diffusion control and including the results of the batch equilibrium and batch kinetics experiments, provides reasonable prediction of the results of dynamic ion-exchange column performance tests.

Prudich, M.E.; Cronauer, D.C.; Marcelin, G.

1987-01-01

52

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

53

In Situ Investigations of Ion Exchange Processes in Microporous Materials  

Microsoft Academic Search

The mechanism by which ions exchange in microporous and layered solids, such as zeolites and clays for example, has important implications in areas as diverse as soil fertility and environmental remediation. A detailed characterization of the ion-exchange pathway, the structural consequences of ion exchange and the specific sites involved in the course of exchange, is desirable. A probe that is

Y. Lee; J. B. Parise; J. C. Hanson

2001-01-01

54

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

PubMed

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

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

2012-01-15

55

Solidification of ion exchange resin wastes in hydraulic cement  

SciTech Connect

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

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

1982-01-01

56

Radiation testing of organic ion exchange resins.  

National Technical Information Service (NTIS)

A number of ion exchange materials are being evaluated as part of the Tank Waste Remediation System (TWRS) Pacific Northwest Laboratory (PNL) Pretreatment Project for the removal of (sup 137)Cs from aqueous tank wastes. Two of these materials are organic ...

C. D. Carlson L. A. Bray S. A. Bryan

1995-01-01

57

Radionuclide Leaching from Organic Ion Exchange Resin.  

National Technical Information Service (NTIS)

Laboratory tests were performed to examine the efficacy of leach treatments for decontaminating organic ion exchange resins (OIER), which have been found in a number of samples retrieved from K East Basin sludge. Based on process records, the OIER found i...

C. H. Delegard D. E. Rinehart

1999-01-01

58

Treatment of Spent Ion-Exchange Resins.  

National Technical Information Service (NTIS)

PMMA was studied with the aim to evaluate its usefulness as an incorporation medium for the final containment of spent ion-exchange resins. The study of the effect of water content (ranging from 25 to 100%) of the incorporated resin into PMMA on the compr...

N. K. Ghattas N. E. Ikladious S. B. Eskander

1981-01-01

59

THE IRRADIATION OF ION EXCHANGERS IN JEEP  

Microsoft Academic Search

Several organic and inorganic ion exchanger materials were irradiated in ; JEEP. Radiation effects are dcscribed and dependence on dose rate and quality of ; the radiation is discussed. By comparing the action of different kinds of ; ionizing radiation, possible reaction mechanisms are discussed. (authl;

Nater

1959-01-01

60

Hydration of purolite S950 ion exchanger in deprotonated forms  

NASA Astrophysics Data System (ADS)

A quantitative evaluation of the degree of hydration, including the ratios of water with different energies in the phase of the aminophosphonic exchanger Purolite S950 in sodium, copper, and nickel forms is conducted. The changes in the Gibbs free energy and enthalpies of hydration and dehydration are determined. It is found that the amount of bound water decreases upon the transition from nickel to copper, especially to the sodium forms of the ion exchanger, and that changes in the Gibbs energy and enthalpy are greatest upon the hydration of the sodium form of polyampholytes.

Gapeev, A. A.; Bondareva, L. P.; Buzin, M. I.; Kornienko, T. S.

2013-05-01

61

Graphene/Ionic liquid composite films and ion exchange.  

PubMed

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

62

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.

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

2014-01-01

63

Ion exchange in a zeolite-molten chloride system  

SciTech Connect

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

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

1997-07-01

64

Synthetic inorganic ion exchange materials XLIV: Synthesis and ion exchange properties of cubic niobic acid (HNbO{sub 3})  

SciTech Connect

A cubic niobic acid (C-NbA) was synthesized by Li{sup +}/H{sup +} ion exchange reaction with an 8 M (mol dm{sup {minus}3}) nitric acid solution from LiNbO{sub 3}. The LiNbO{sub 3} was obtained by heating a mixture of Li{sub 2}CO{sub 3} and Nb{sub 2}O{sub 5} with molar ratio of 1:1 at 900 C for 24 h. X-ray diffraction pattern of C-NbA was indexed to a cubic structure (space group Im3), with the lattice constant a{sub o} = 7.6445 {angstrom} ({angstrom} = 100 pm). The C-NbA product showed an exchange reaction equivalent to one proton per one Li{sup +} in a mixed solution of lithium nitrate and lithium hydroxide. The pH titration curves of C-NbA on the Li{sup +}/H{sup +} exchange system indicated a weak monobasic acid. C-NbA showed high uptake for lithium ions, whereas no appreciable amount of uptake was observed for other alkali metal ions in the pH range 4--12. An extremely high selectivity was found for lithium ions, and the separation factor ({alpha}) of lithium ions to other alkali metal ions was higher than 10{sup 3}.

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

1999-07-01

65

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

66

SPEEDUP{trademark} ion exchange column model  

SciTech Connect

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

Hang, T.

2000-03-06

67

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, D.P.

1986-10-23

68

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) [Berkeley, CA

1988-01-01

69

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) [Berkeley, CA

1989-01-01

70

An Investigation of the Transport Properties of Ion Exchange Membranes.  

National Technical Information Service (NTIS)

As part of a continuing study of the factors affecting the transport of ions and water through ion exchange membranes, conductivity and water transfer measurements have been carried out in a highly crosslinked organic anion exchange membrane for anions of...

J. H. B. George C. R. Schlaikjer

1966-01-01

71

An Empirical Formula From Ion Exchange Chromatography and Colorimetry.  

ERIC Educational Resources Information Center

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

Johnson, Steven D.

1996-01-01

72

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

73

Porous solid ion exchange wafer for immobilizing biomolecules  

DOEpatents

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

74

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

75

Water softening by combination of ultrasound and ion exchange  

Microsoft Academic Search

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

M. H. Entezari; M. Tahmasbi

2009-01-01

76

A review of the radiation stability of ion exchange materials  

Microsoft Academic Search

A comprehensive literature survey on the radiation stability of ion exchangers resulted in the publication of an extensive data compilation on the effects of ionizing radiation on synthetic organic ion exchangers in this journal (Vol. 97, No. 1). This paper is a brief review of the majorfindings of this literature survey along with similar information on synthetic inorganic ion exchangers.

K. K. S. Pillay

1986-01-01

77

Radiation testing of organic ion exchange resins  

Microsoft Academic Search

A number of ion exchange materials are being evaluated as part of the Tank Waste Remediation System (TWRS) Pacific Northwest Laboratory (PNL) Pretreatment Project for the removal of ¹³⁷Cs from aqueous tank wastes. Two of these materials are organic resins; a phenol-formaldehyde resin (Duolite CS-100) produced by Rohm and Haas Co. (Philadelphia, Pennsylvania) and a resorcinol-formaldehyde (RF) resin produced by

C. D. Carlson; L. A. Bray; S. A. Bryan

1995-01-01

78

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

79

Ion Exchange Temperature Testing with SRF Resin  

SciTech Connect

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

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

2012-03-01

80

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

SciTech Connect

Sorption of tellurium from solutions of telluric acid under dynamic and static conditions by anion-exchangers and amphoteric ion-exchangers containing various ionic groups was studied and the influence of the ion form, pH of the medium, presence of electrolytes, and the H/sub 6/TeO/sub 6/ concentration in the original solutions was determined. The mechanism of sorption of tellurium (VI) by anion-exchangers was deduced from sorption and IR-spectroscopic data. Differences in the behavior of tellurium and selenium were used for separating these elements in 0.05 N H/sub 2/SeO/sub 4/ + 0.05 N H/sub 6/TeO/sub 6/ solution of pH = 1.0 with the aid of EDE-10P anion-exchange resin.

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

1981-10-20

81

Novel silica-based ion exchange resin  

SciTech Connect

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

NONE

1997-11-01

82

Synthesis of perrhenic acid using ion exchange method  

Microsoft Academic Search

The paper presents results of the study for obtaining perrhenic acid from aqueous ammonium perrhenate solutions by ion exchange. Two ways of perrhenic acid synthesis have been examined: sorption of perrhenate anion on selected anion exchange resins (followed by elution of the sorbed rhenium as HReO4), and sorption of ammonium ion on selected cation exchange resins. The method of ammonium

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

2007-01-01

83

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

DOEpatents

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

Wertsching, Alan K. (Idaho Falls, ID) [Idaho Falls, ID; Peterson, Eric S. (Idaho Falls, ID) [Idaho Falls, ID; Wey, John E. (Idaho Falls, ID) [Idaho Falls, ID

2007-12-25

84

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

85

Ion exchange polymers and method for making  

NASA Technical Reports Server (NTRS)

An ion exchange polymer comprised of an alkali metal or alkaline earth metal salt of a poly(carboxylic acid) in a poly(vinyl acetal) matrix is described. The polymer is made by treating a mixture made of poly(vinyl alcohol) and poly(acrylic acid) with a suitable aldehyde and an acid catalyst to cause acetalization with some cross-linking. The material is then subjected to an alkaline aqueous solution of an alkali metal salt or an alkali earth metal salt. All of the film forming and cross-linking steps can be carried out simultaneously, if desired.

Philipp, Warren H. (inventor); Street, Kenneth W., Jr. (inventor)

1994-01-01

86

Proton Ratio of HL-2A Bucket Ion Source  

NASA Astrophysics Data System (ADS)

For heating the tokamak plasma effectively, the ion source must be capable of producing ions with high proton ratio. The proton ratio, which is found to be more than 65.6% at the ion current of 19.6 A with the extraction voltage of 39.6 kV, is measured with an image spectrograph by Doppler shift effect of Balmer-?-radiation spectrum emitted from fast hydrogen particles. The tendency of proton ratio with the ion density in experiment is almost the same as the mode devised by Zhang et al. Okumura et al. only gave the affection of the plasma volume and ion loss area on the proton ratio, but the relationship between the ion density in chamber and the proton ratio was not presented. We give the relationship.

Yu, Li-Ming; Lei, Guang-Jiu; Cao, Jian-Yong; Yang, Li-Mei; Jiang, Shao-Feng; Han, Xiao-Yu; Zhang, Xian-Ming; Sun, Ping; Zou, Gui-Qing; Lu, Da-Lun; Liu, He; Jiang, Tao; Duan, Xu-Ru

2010-04-01

87

Spectroscopic and ion exchange studies on modified cotton linters  

Microsoft Academic Search

Cation exchange resin was prepared by phosphorylation of cotton linters. The effect of different treatments (alkali or acid) of cotton linters on phosphorylation process was studied. This treatment increases the efficiency of the produced resin toward metal ions uptake (Cu, Fe, Mn, Ni, Pb, Zn). The effect of pH value of metal ion solution on the efficiency of ion exchanger

A M A Nada; S S Hamed; S I Soliman; S Abd El Mongy

88

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

1985-05-07

89

Investigation of Inorganic Ion Exchange Membranes for Electrodialysis Applications.  

National Technical Information Service (NTIS)

The mixed oxides of Groups III, IV, and V were investigated as selective ion exchangers for incorporation into electrodialysis membranes. Aluminum vanadate demonstrated reversible exchange properties. Flexible membranes formed from aluminum vanadate excha...

G. A. Guter H. K. Bishop

1967-01-01

90

Revised Thermal Analysis of LANL Ion Exchange Column.  

National Technical Information Service (NTIS)

This document updates a previous calculation of the temperature distributions in a Los Alamos National Laboratory (LANL) ion exchange column. LANL operates two laboratory-scale anion exchange columns, in series, to extract Pu-238 from nitric acid solution...

2006-01-01

91

Radionuclide Leaching from Organic Ion Exchange Resin  

SciTech Connect

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

Delegard, C.H.; Rinehart, D.E.

1999-04-02

92

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

93

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

94

Conducting polymers as ion-exchangers for water purification  

Microsoft Academic Search

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

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

2001-01-01

95

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

96

Application of Ion Exchange Membranes in Chloride Related Electrochemical Technology.  

National Technical Information Service (NTIS)

Contents: General Introduction; The Fundamental Aspect of Ion Exchange Membrane; The Regeneration of Hydrogen Chloride in the Electrowinning of Metal Chlorides in Membrane Equipped; Ion Transport in a Two-Membrane Electrowinning Cell for the Production of...

L. Z. Liao

1997-01-01

97

Complexation ion-exchange chromatography of some metal ions on papers impregnated with Ti(IV)-based inorganic ion exchangers.  

PubMed

The chromatographic behavior of 40 metal ions is studied on titanium (IV) arsenate, titanium (IV) phosphate-, titanium (IV) molybdate-, titanium(IV) tungstate-, and titanium(IV) selenite-impregnated papers in 0.1M oxalic, citric, and tartaric acid as mobile phases. Similar studies are carried out on Whatman No. 1 papers for comparison. The ion-exchange capacity of these papers is determined, and their selectivity for different cations is discussed. The mechanism of migration is explained in terms of ion-exchange, precipitation, and adsorption. The prediction of elution sequence from RF values is also checked. The average Ri is found to be almost linearly dependent on the charge of the metal ions. The effect of the pKa of complexing acids on average RF values of 3d series metal ions is explained. A number of binary and ternary separations are achieved. PMID:10677834

Sharma, S D; Gupta, R

2000-02-01

98

Theorization on ion-exchange equilibria: activity of species in 2-D phases.  

PubMed

Ion-exchange reactions are naturally occurring at soil and sediment/water interphases, determining soil fertility and water quality. These ion-exchange reactions with inorganic and organic exchangers are applied to chemical analysis, recovery of useful ions from low-grade ores (potentially from sea water), water purification including the preparation of "ultrapure" water, production of foods and medicines, therapy, and other uses. It is important to theorize about or to model ion-exchange reactions for quantitative explanations of ion-exchange phenomena and for efficient operation of ion-exchange processes. This paper describes the modeling of ion-exchange equilibria for hydroxyl sites on metal oxides and carboxyl sites in resins with monovalent cations (alkali metal ions), a monovalent anion (nitrate ion), and divalent heavy metal ions. The procedure of modeling is as follows: the stoichiometry and material balance equations of the respective ion-exchange reactions were established based on findings here and by others. The equilibrium conditions were given by the Frumkin equation, where the mass-action relation is modified with lateral interactions between species at the interphase. The model equations were fitted to the measured data and model parameter values were determined by nonlinear regression analysis. The formation of bonds between ions and exchanger sites was evaluated by the equilibrium constant and the suppression of bond formation by electrostatic, geometric, and other lateral interactions was evaluated by the interaction constant. It was established that the properties of ions are determined by the valence, size, and hydration state of the ions. Monovalent ions (anions and cations) react with oxide surface hydroxyl and resin carboxyl sites as hydrated ions and form loose ion-site pairs by a weak electrostatic bond (nonspecific adsorption). However, the lateral interactions are large because of a large polarization of the ion-site pairs. When the monovalent cations are dehydrated to react with carboxyl sites in narrow resin nanopores, the bond formation is difficult because energy for dehydration is necessary. The suppressive lateral interactions here are small because of a small polarization of the dehydrated ion-site pairs that are in direct contact. Divalent heavy metal ions react with oxide hydroxyl sites by replacing their hydrated water molecules and form ion-site pairs in direct strong contact (specific adsorption). The bond formation becomes easier with increasing charge density of the ions evaluated by the charge/radius ratio, agreeing with the order of these ions to form hydroxo complexes in solution. The suppressive lateral interaction is, however, small for ions with large charge densities, because a strong contact bond reduces the polarization of ion-site pairs by neutralization. The properties of exchangers are functions of the molecular and pore environments around the functional groups. The acid-base nature of oxide surface-hydroxyl groups is determined by the electronegativity of surrounding lattice metal ions, and that of resin carboxyl groups by the electron-repelling effect of adjacent methyl groups. Pores in oxides have diameters sufficient to accommodate hydrated ions, and the suppression is large because of repulsion from ions adsorbed on opposite pore walls (across-pore interaction). Pores in resins differentiate ions that can access or not access sites on the internal surfaces of the pores. Narrow nanopores with diameters less than those of the hydrated ions require ions to dehydrate before they can enter. The ion-exchange reactivity here is small, as described above for dehydrated monovalent ions. In wide nanopores where hydrated ions can enter, bond formation is easier, but suppression is greater because of a larger polarization of hydrated ion-site pairs and also of the across-pore interaction. Macropores have diameters much larger than those of the hydrated ions and the bond formation is the same as that in wide nanopores, but the suppression is smaller because of the

Tamura, Hiroki

2004-11-01

99

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

100

Charge exchange ion number density distribution in Hall thruster plume  

Microsoft Academic Search

The charge exchange (CEX) ions by the collisions between energetic ions and slow neutral particles in a Hall thruster plume are thought a source of the ions coming back to the satellite. Therefore, mechanical plume shielding has been proposed to prevent the CEX ions from spreading out from near exit region. In order to optimize the shield length, CEX reactions

Shigeru Yokota; Daichi Sakoh; Makoto Matsui; Kimiya Komurasaki; Yoshihiro Arakawa

2008-01-01

101

Radiation testing of organic ion exchange resins  

SciTech Connect

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

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

1995-09-01

102

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

103

CHLORIDE REMOVAL FROM KRAFT LIQUORS USING ION EXCHANGE TECHNOLOGY  

Microsoft Academic Search

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

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

104

The effects of ionizing radiations on synthetic organic ion exchangers  

Microsoft Academic Search

Effects of ionizing radiations on organic ion exchangers are recognized as a vexing problem in the processing of special nuclear materials and high specific activity radioactive waste forms. An extensive literature survey, started in 1976 and updated periodically, indicates that radiation decomposition of ion exchange materials has the potential for a variety of undesirable consequences. It is also apparent from

K. K. S. Pillay

1986-01-01

105

Improved Amphoteric Ion Exchanger and Its Manufacturing Method.  

National Technical Information Service (NTIS)

This invention relates to an amphoteric ion exchanger comprising a block copolymer composed of a polymer chain poly A exp - having a cation exchange group, poly B exp + polymer chain having an anion exchange group, and poly C polymer chain not having an i...

T. Kodaka H. Onuma

1985-01-01

106

Effects of ion-exchangeable cations on coal ash mineralogy  

Microsoft Academic Search

The purpose of this study was to investigate the effect of ion-exchangeable cations on ash mineralogies of two coals having different sodium contents. In addition, ashes of the same coals from which the exchangeable cations were removed were compared with ashes of the non-exchanged coals to determine the effect of removing alkali cations on ash mineralogies. Two lignites from the

S. K. Falcone; J. P. Hurley; H. H. Schobert

1984-01-01

107

Ion exchange properties of novel hydrous metal oxide materials  

SciTech Connect

Hydrous metal oxide (HMO) materials are inorganic ion exchangers which have many desirable characteristics for catalyst support applications, including high cation exchange capacity, anion exchange capability, high surface area, ease of adjustment of acidity and basicity, bulk or thin film preparation, and similar chemistry for preparation of various transition metal oxides. Cation exchange capacity is engineered into these materials through the uniform incorporation of alkali cations via manipulation of alkoxide chemistry. Specific examples of the effects of Na stoichiometry and the addition of SiO{sub 2} to hydrous titanium oxide (HTO) on ion exchange behavior will be given. Acid titration and cationic metal precursor complex exchange will be used to characterize the ion exchange behavior of these novel materials.

Gardner, T.J.; McLaughlin, L.I.

1996-12-31

108

Exchange and reduction of Cu 2+ ions in clinoptilolite  

Microsoft Academic Search

The ion-exchange and reduction processes for Cu2+ ions in clinoptilolite from the Caimanes deposit (Moa, Cuba) were studied at different temperatures. The ion-exchange studies were done to determine the kinetic parameters of Cu2+ removal from solution by this clinoptilolite modified previously to NH+4 form, and thermodynamic parameters of Cu2+ elution from zeolite using NH4Cl solution. The results show that temperature

I. Rodríguez Iznaga; V. Petranovskii; G. Rodríguez Fuentes; C. Mendoza; A. Benítez Aguilar

2007-01-01

109

Vibrational spectroscopy of ion exchange membranes  

NASA Astrophysics Data System (ADS)

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

Kumari, Dunesh

110

Process for the elution of ion exchange resins in uranium recovery  

SciTech Connect

Process for the recovery of uranium from a pregnant lixiviant employed in uranium leaching operations in which the uranium is concentrated by ion exchange resin. The ion exchange resin is eluted with an eluant containing 0.05-0.5 molar ammonium carbonate. The eluant also contains a base such as ammonium hydroxide in an amount sufficient to increase the ph to a value within the range of 9.0-11.0, thus increasing the carbonate/bicarbonate ratio. This enables the use of a relatively small quantity of ammonium carbonate to provide the desired carbonate ion concentration during the elution step.

Yan, T.

1981-07-28

111

Gadolinium-hydrogen ion exchange of zirconium phosphate  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

112

Ion-exchange kinetics in natural heulandite and clinoptilolite  

Microsoft Academic Search

The kinetics of sorption of Ca2+ ions from aqueous solution by K+-substituted forms of heulandite and clinoptilolite have been studied at 298 K. The K+-Ca2+ ion exchange in heulandite and clinoptilolite is described by an internal diffusion mechanism. Self-diffusion coefficients were determined for Ca2+ ions in these zeolites.

G. N. Al'tshuler; M. P. Kirsanov

1991-01-01

113

Ion exchange capacity of Nafion and Nafion composites  

SciTech Connect

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 {+-} 8. This suggests that {approx_gt} 13% of the exchange sites within recast films are inaccessible for ion exchange; for 1,100 equivalent weight material, {approx_gt} 25% of the sulfonates are inaccessible. Equivalent weight results are consistent with an ordered interfacial domain between Nafion and the microbeads. A fractal model based on microbead radii, microbead fraction, and interfacial domain thickness provides a predictive model for designing composites with increased exchange capacity and cation transport.

Chen, T.Y.; Leddy, J.

2000-03-21

114

Removal of thiosulfates from return waters by ion exchange  

SciTech Connect

The authors select an anion-exchange resin and its ionic form having high exchange capacity for thiosulfate, from which the sorbed thiosulfate ions can be effectively desorbed. Three types of strongly basic anion-exchangers were used: AV-17; AV-1710P; AV-29-10P. The experimental results showed that all three aninon-exchangers had approximately the same capacity for thiosulfate ions. Curves representing sorption and regeneration during purification of model solutions are show. The resins were regenerated under dynamic conditions by 1 N sodium sulfate solution. The degree of regeneration was 95%.

Parkhomovskii, V.L.; Kryzhandvskii, M.M.; Savva, V.P.; Timofeeva, I.V.

1986-08-01

115

Ion-exchanged glass waveguide technology: a review  

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

116

Charge exchange collisions between alkaline-earth ions and alkali atoms  

Microsoft Academic Search

The ratio of the charge exchange cross sections for Ba+ (5d) and Ba+(6s) on Na, Rb and Cs, for Sr+(4d) and Sr+(5s) on Na and Rb, and for Ca+(3d) and Ca-(4s) on Na have been measured for ion impact energies between 0.5 keV and 30 keV. For the collisions with Na, absolute charge exchange cross section values are derived using

L. Vermeeren; P. Lievens; A. Buekenhoudt; R. E. Silverans

1992-01-01

117

Conductometric and microcalorimetric analysis of the alkaline-earth\\/alkali-metal ion exchange onto polyacrylic acid  

Microsoft Academic Search

The specificity of the exchange between divalent (Di2+?=?Ca2+ or Ba2+) and monovalent (M+?=?Li+, Na+ or K+) ions onto a polyacrylic chain is examined using conductometric and microcalorimetric techniques. Assuming the formation\\u000a of a bidentate complex between the Di2+ and the carboxylate groups, the conductometric data give the exchange ratio (Di2+\\/M+) and the speciation of the acrylic groups. No significant difference

I. Pochard; A. Foissy; P. Couchot

1999-01-01

118

Cesium Ion Exchange Loading Kinetics Testing with SRF Resin  

SciTech Connect

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

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

2012-11-02

119

Recovery and separation of Cs137, Sr90, and Th-232 from a simulated high level nuclear liquid waste using a Multiplestage Countercurrent batch contactor ion exchange system  

Microsoft Academic Search

The radioisotopes ¹³⁷Cs, ⁹°Sr, and ²³²Th level nuclear liquid wastes, were recovered and sequentially separated using an 8-stage flask simulation of a Multiplestage Countercurrent Batch Contactor Ion Exchange System (MCBC). The solution normality ratio used for three ions Cs:Sr:Th was 1:1:1. The ratio of the total meg of solution phase ions to resin ion exchange capacity was 16:15. The solution

1985-01-01

120

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...

121

FRACTIONATION OF COMPLEX MIXTURES USING AND ION-EXCHANGE METHODOLOGY  

EPA Science Inventory

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

122

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

123

Study on dry decontamination using ion exchange polymer.  

National Technical Information Service (NTIS)

Through the project of (sup A) study on dry decontamination using ion exchange polymer(sup ,) the followings were investigated. 1. Highly probable decontamination technologies for the decontamination were investigated. 2. Development of gel type decontami...

K. J. Jung B. G. Ahn

1997-01-01

124

Application of pressurized ion exchange to separations of transplutonium elements  

SciTech Connect

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

Campbell, D.O.

1980-01-01

125

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

Microsoft Academic Search

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

Sami ?ahin

2002-01-01

126

Adsorption of glutamic acid on weakly basic ion exchanger: Equilibria  

Microsoft Academic Search

Equilibria for adsorption of l-glutamic acid on a general weakly basic ion exchanger which has only one kind of fixed ammonium group are investigated theoretically and experimentally. The experimental equilibrium isotherm for adsorption of l-glutamic acid on the commercial weakly basic ion exchanger was independent of the initial concentration of l-glutamic acid but depended on pH of the solution significantly.

Hiroyuki Yoshida; Noboru Kishimoto

1995-01-01

127

Ion Exchange Application of Overpressured Thin-Layer Chromatography  

Microsoft Academic Search

The application of overpressured thin-layer chromatography introduced into the field of ion exchange chromatography. The basic differences between overpressured thin-layer chromatography and classical thin-layer chromatography are discussed including the distinction between the separations performed on thin-layer plates containing silica gel and a mixture of ion exchanger material and silica gel. The basic increase of flow velocity of solvent front with

Huba Kalász; János Nagy

1981-01-01

128

Controlled transdermal iontophoresis by ion-exchange fiber  

Microsoft Academic Search

The objective of this study was to assess the transdermal delivery of drugs using iontophoresis with cation- and anion-exchange fibers as controlled drug delivery vehicles. Complexation of charged model drugs with the ion-exchange fibers was studied as a method to achieve controlled transdermal drug delivery. Drug release from the cation-exchange fiber into a physiological saline was dependent on the lipophilicity

Tarja Jaskari; Marja Vuorio; Kyösti Kontturi; Arto Urtti; José A Manzanares; Jouni Hirvonen

2000-01-01

129

Revised Thermal Analysis of LANL Ion Exchange Column  

Microsoft Academic Search

This document updates a previous calculation of the temperature distributions in a Los Alamos National Laboratory (LANL) ion exchange column.1 LANL operates two laboratory-scale anion exchange columns, in series, to extract Pu-238 from nitric acid solutions. The Defense Nuclear Facilities Safety Board has requested an updated analysis to calculate maximum temperatures for higher resin loading capacities obtained with a new

Laurinat

2006-01-01

130

Thorium Uptake on Synthetic Inorganic Ion Exchangers  

Microsoft Academic Search

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

Lina Al-Attar; Youssef Budeir

2011-01-01

131

Ion exchange equilibria in zeolite minerals  

Microsoft Academic Search

Cation exchange equilibria of the most common sedimentary zeolites are reviewed. Selected exchange isotherms and thermodynamic equilibrium constants are reported and interpreted in terms of selectivity of one cation over another. Selectivity sequences of various zeolites are compared with each other in the light of Eisenman's theory and utilized to predict or explain specific practical performances.

C. Colella; Napoli Federico; Piazzale V. Tecchio

1996-01-01

132

Electrodeionization 2: The migration of nickel ions absorbed in a flexible ion-exchange resin  

Microsoft Academic Search

The removal of nickel ions from a low cross-linked ion-exchange resin using an applied electrical potential gradient was studied. The potential gradient across a bed of ion-exchange particles, in which nickel ions were absorbed, was varied by two methods. One involved a change of cell voltage across beds of constant width, the other a change of bed width at constant

P. B. Spoor; W. R. Ter Veen; L. J. J. Janssen

2001-01-01

133

Ion exchange of some heavy metal ions from polar organicsolvents into zeolite  

Microsoft Academic Search

In the present study the possibility of ion exchange of heavy metal ions using polar organic solvents and naturalzeolite clinoptilolite is approached. The organic solvents used are nearly pure ethanol and acetone. These solventsare compared to deionized water. The heavy metal ions studied are Cu2+, Cr3+ and Fe3+. While ion exchange levelsin water are much greater for Fe3+ (53.1%) in

V. J. Inglezakis; M. D. Loizidou

2007-01-01

134

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

135

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

136

Ion exchange membrane based on block copolymers. Part III: preparation of cation exchange membrane  

Microsoft Academic Search

A new type of ion exchange membrane was investigated for the purpose of applying electrodialysis process. The cation exchange membrane was prepared by sulfonation of the home-made block copolymers of polysulfone (PSf) and polyphenylenesulfidesulfone (PPSS). The lowest measured membrane area resistance, equilibrated in 2M (mol\\/dm3) KCl aqueous solution, was 2.5?cm2. The cation exchange capacity reached up to 1.9meq\\/(g-dry-resin), and the

Gab-Jin Hwang; Haruhiko Ohya; Toshiyuki Nagai

1999-01-01

137

Waste-Pond Treatment with Immobilized Liquid Ion-Exchangers.  

National Technical Information Service (NTIS)

The feasibility of using reagent-impregnated ion-exchange fibers to separate and remove heavy-metal ions from low-concentration solutions is established. Modules containing several hundred fibers were developed and proved to be fouling-resistant. Waste po...

W. C. Babcock R. W. Baker M. B. Chidlaw D. T. Friesen G. A. Gunson

1981-01-01

138

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

139

Natural zeolites and their ion exchange behavior towards chromium  

Microsoft Academic Search

In this work studies have been performed which demonstrate that trivalent chromium cations may be retained by naturally occuring zeolites. The experimental work perfomed on the natural zeolite clinoptilolite, which is found in abudant quantities in Greece, showed that the ion exchange process is quite rapid and high quantities of chromium ions are removed from the aqueous solutions in a

M. Loizidou; K. J. Haralambous; A. Loukatos; D. Dimitrakopoulou

1992-01-01

140

Desalination of brackish waters using ion exchange media.  

SciTech Connect

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

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

2005-01-01

141

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

142

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

143

Ion-exchange purification of aqueous solutions of secondary caprolactam  

Microsoft Academic Search

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

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

1971-01-01

144

Silicon Removal from Waste Simulants via Ion Exchange  

SciTech Connect

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

Wilmarth, W.R.

2002-09-23

145

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

146

Radioactive halos and ion microprobe measurement of Pb isotope ratios  

NASA Technical Reports Server (NTRS)

This investigation was to obtain, if possible, the Pb isotope ratios of both lunar and meteoritic troilite grains by utilizing ion microprobe techniques. Such direct in situ measurement of Pb isotope ratios would eliminate contamination problems inherent in wet chemistry separation procedures, and conceivably determine whether lunar troilite grains were of meteoritic origin. For comparison purposes two samples of meteoritic troilite were selected (one from Canyon Diablo) for analysis along with two very small lunar troilite grains (approximately 50-100 microns). It was concluded that the ion microprobe as presently operating, does not permit the in situ measurement of Pb isotope ratios in lunar or meteoritic troilite. On the basis of these experiments no conclusions could be drawn as to the origin of the lunar troilite grains.

Gentry, R. V.

1974-01-01

147

Silver nanocluster formation in silicate glass by single step ion-exchange  

Microsoft Academic Search

We report the formation of silver nanoclusters of average size ?1.1 nm in a single step ion-exchanged silica glass. Silver clusters are formed in a glass during ion-exchange by fine-tuning the ion-exchange parameters such as salt composition, temperature and time. Such nanocluster formation during ion-exchange preserves the waveguiding properties of the ion-exchanged surface of the glass making them suitable for nonlinear

G. Medhi; P. Nandi; S. Mohan; G. Jose

2007-01-01

148

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

Microsoft Academic Search

The kinetics of zinc and lead ions removal by modified zeolite-clinoptilolite has been investigated. The rate of the ion exchange process for lead ions is faster than for zinc ions, as well as the time needed to reach the equilibrium. The ion exchange capacity of zeolite of lead ions is doubly higher than that of zinc ions. Diffusion models according

M. Trgo; J. Peri?; N. Vukojevi? Medvidovi?

2006-01-01

149

In Situ Investigations of Ion Exchange Processes in Microporous Materials  

NASA Astrophysics Data System (ADS)

The mechanism by which ions exchange in microporous and layered solids, such as zeolites and clays for example, has important implications in areas as diverse as soil fertility and environmental remediation. A detailed characterization of the ion-exchange pathway, the structural consequences of ion exchange and the specific sites involved in the course of exchange, is desirable. A probe that is both time- and structure-sensitive allows resolution of which specific sites are involved, along with the effects of different cation types on the uptake and release of ions. In order to discern the mechanism of ion exchange, it is necessary not only to observe the course of the reaction, which can now be done routinely using energy dispersive X-ray diffraction at synchrotron sources, but also to collect dynamic diffraction data of sufficient quality to allow structure refinement using Rietveld structure refinement techniques. This at present requires the collection of monochromatic data. Tradeoffs between time-resolution, peak-to-background discrimination and structural resolution are often required and depend on the problem at hand. We have developed a number of strategies for in situ ion exchange techniques that probe both structural and kinetic information from dynamic solid media. Examples include investigations of the site-specific ion-exchange mechanism in zeolite LSX using a combination of ex situ and in situ time-resolved synchrotron X-ray powder diffraction, Iterative Target Transformation Factor Analysis (ITTFA) and Rietveld structural refinements. Measurement of competitive ion depletion curves showed that the newly synthesized gallosilicate TsG-1 is more selective for Sr than mineral clinoptilolite, and the structural pathway of Sr-exchange in TsG-1 was monitored by in situ and ex situ synchrotron X-ray powder diffraction. In those cases where full structure refinement is desirable using less than optimal powder diffraction data, we found it necessary to first obtain excellent models from partially and fully ion exchanged materials, preferably from single crystal data. These allow the setting of realistic constraints on interatomic distances to supplement data with high time-resolution.

Lee, Y.; Parise, J. B.; Hanson, J. C.

2001-12-01

150

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

151

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

152

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

1997-01-01

153

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

154

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

155

H/D exchange of gas phase bradykinin ions in a linear quadrupole ion trap.  

PubMed

The gas phase H/D exchange reaction of bradykinin ions, as well as fragment ions of bradykinin generated through collisions in an orifice skimmer region, have been studied with a linear quadrupole ion trap (LIT) reflectron time-of-flight (rTOF) mass spectrometer system. The reaction in the trap takes only tens of seconds at a pressure of few mTorr of D2O or CD3OD. The exchange rate and hydrogen exchange level are not sensitive to the trapping q value over a broad range, provided q is not close to the stability boundary (q = 0.908). The relative rates and hydrogen exchange levels of protonated and sodiated +1 and +2 ions are similar to those observed previously by others with a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer system. The doubly and triply protonated ions show multimodal isotopic distributions, suggesting the presence of several different conformations. The y fragment ions show greater exchange rates and levels than a or b ions, and when water or ammonia is lost from the fragment ions, no exchange is observed. PMID:12586457

Mao, Dunmin; Douglas, D J

2003-02-01

156

MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS  

SciTech Connect

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

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

2011-09-20

157

Development and evaluation of ion exchange hollow fibers. [vinyl copolymers  

NASA Technical Reports Server (NTRS)

An ion exchange hollow fiber impregnated with a vinylpyridine base was developed. The basic exchange resin used to impart the necessary permselectivity to the hollow fiber is a copolymer of vinylpyridine and dibromoethane prepared according to Rembaum. A slight pressure was used to impregnate the exchange monomer mixture into the void structure of the fiber wall, and with maintenance of subambient temperatures, the rate of cross-linking is slow enough to allow the growing polymer to permeate the wall structure before significant increase in polymer molecular weight. These ion exchange fibers are produced from polyacrylonitrile hollow fibers with an appropriate wall structure that enables the impregnating vinylpyridine monomer mixture to form a truly semipermeable anion barrier after curing.

Smith, J. K.

1975-01-01

158

Evaluating ion exchange for removing radium from ground water  

Microsoft Academic Search

The article focuses on the results of bench- and pilot-scale studies of ion exchange processes for radium removal from groundwater in Lemont, Ill. Batch and column studies indicated a very high resin selectivity for radium compared with common cations. Exhaustion-regeneration studies with a variety of resins showed that a standard gel-type strong-acid cation exchanger is most suitable for radium removal

S. Subramonian; D. Clifford; W. Vijjeswarapu

1990-01-01

159

Evaluating Ion Exchange for Removing Radium From Groundwater  

Microsoft Academic Search

This article, the second in a series, focuses on the results of bench-and pilot-scale studies of ion exchange processes for radium removal from groundwater in Lemont, Ill. Batch and column studies indicated a very high resin selectivity for radium compared with common cations. Exhaustion-regeneration studies with a variety of resins showed that a standard gel-type strong-acid cation exchanger is most

Suresh Subramonian; Dennis Clifford; Winston Vijjeswarapu

1990-01-01

160

RADIATION STABILITY OF ION EXCHANGE RESINS  

Microsoft Academic Search

the structure of the micromolecular framework, the chemical nature, the ; exchange group, the type of crosslinkage and the radiation medium. Both in DVB-; styrene copolymers and in phenol-formaldehyde resins the C--R bond (KF-1 and RF ; resins) was more resistant towards ionizing radiation than the C--S bond (KU-2, ; KU-1 resins). By changing the structure of the crosslinking component

E. D. Kiseleva; K. V. Chmutov; V. N. Krupnova

1962-01-01

161

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

162

Controlled transdermal iontophoresis by ion-exchange fiber.  

PubMed

The objective of this study was to assess the transdermal delivery of drugs using iontophoresis with cation- and anion-exchange fibers as controlled drug delivery vehicles. Complexation of charged model drugs with the ion-exchange fibers was studied as a method to achieve controlled transdermal drug delivery. Drug release from the cation-exchange fiber into a physiological saline was dependent on the lipophilicity of the drug. The release rates of lipophilic tacrine and propranolol were significantly slower than that of hydrophilic nadolol. Permeation of tacrine across the skin was directly related to the iontophoretic current density and drug concentration used. Anion-exchange fiber was tested with anionic sodium salicylate. The iontophoretic flux enhancement of sodium salicylate from the fiber was substantial. As the drug has to be released from the ion-exchange fiber before permeating across the skin, a clear reduction in the drug fluxes from the cationic and anionic fibers were observed compared to the respective fluxes of the drugs in solution. Overall, the ion-exchange fibers act as a drug reservoir, controlling the release and iontophoretic transdermal delivery of the drug. PMID:10825552

Jaskari, T; Vuorio, M; Kontturi, K; Urtti, A; Manzanares, J A; Hirvonen, J

2000-07-01

163

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

164

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

165

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

166

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

SciTech Connect

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

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

2006-08-01

167

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.

168

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

169

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

PubMed

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

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

2013-11-22

170

Removal of metal ions from aqueous solution by cellulose ion exchangers  

SciTech Connect

The sorption of metal ions [Cd(II), Cu(II), Pb(II), Zn(II), Cr(III), V(IV), V(V)] from aqueous solution by Whatman cellulose ion exchangers was investigated as a function of pH. Whatman P-11 (ammonium cellulose phosphate) exhibited better performance than a fibrous anion exchanger (Whatman Cellect-Ion Exchanger DT-1) with respect to their sorption capacities for Cd(II), Cu(II), Co(II), Pb(II), Zn(II), and Cr(III). The Cellect-Ion anion exchanger (DT-1) had a higher sorption for V(IV) and V(V). The ionic form of cellulose phosphate (P-11) influenced their metal sorption capacities.

Kabay, N.; Demircioglu, M.; Yayli, S.; Yuksel, M.; Saglam, M. [Ege Univ., Bornova (Turkey). Dept. of Chemical Engineering] [Ege Univ., Bornova (Turkey). Dept. of Chemical Engineering; Levison, P.R. [Whatman International Ltd., Maidstone (United Kingdom)] [Whatman International Ltd., Maidstone (United Kingdom)

1999-01-01

171

Ion Exchange Membrane Methods for Continuous Removal of Ions from Water and Trace Chemical Analysis.  

National Technical Information Service (NTIS)

Trace analysis of wastewater and natural water samples generally requires extensive sample pretreatment. Separation of the samples from concentrated receiver electrolytes by ion exchange membranes, which results in Donnan dialysis, provided rapid, precise...

J. A. Cox

1978-01-01

172

Nitrate and Perchlorate removal from groundwater by ion exchange  

Microsoft Academic Search

This study was conducted to evaluate the performance of a small scale ion exchange unit (Krudico, Inc of Auborn, IA) for removal of nitrate and perchlorate from groundwater at Lawrence Livermore National Laboratory's Site 300. The unit was able to treat 3,600 gallons of Site 300 groundwater, at an average influent concentration of 100 mg\\/L NOâ⁻ before breakthrough occurred. The

S Burge; R Halden

1999-01-01

173

Purification of dilute hydrofluoric acid by commercial ion exchange resins  

Microsoft Academic Search

This paper describes the results from an experimental study of the purification of dilute hydrofluoric acid (5wt.%) by ion exchange. Hydrofluoric acid was prepared by dilution from technical grade concentrated HF; important amounts of metal impurities were found in the diluted acid, mainly Na, Fe, As, B, Ca, K, Mg, Mn, Mo, PO43?, and Ti. The semiconductor industry developed the

I. Fernández-Olmo; J. L. Fernández; A. Irabien

2007-01-01

174

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...

175

Isomerization of ?-pinene over ion-exchanged natural zeolites  

Microsoft Academic Search

Catalysts prepared by ion exchange of clinoptilolite-based natural zeolite tuffs with NH4+, Ba2+ and Pb2+ were investigated in the isomerization reaction of ?-pinene at atmospheric pressure under nitrogen flow. Activity and selectivity to mono-, bi- and tricyclic products were correlated with acidity strength.

Fehime Özkan; Gönül Gündüz; Oguz Akpolat; Nurgun Be?ün; Dmitry Yu. Murzin

2003-01-01

176

The concept of “capacity” in zeolite ion-exchange systems  

Microsoft Academic Search

In the present paper a study is conducted in order to distinguish the several types of capacity used in the literature on zeolite ion-exchange systems, to verify the use of each capacity type, and to analyze the several experimental methods used for capacity determination. Although the study is focused on zeolite clinoptilolite as a characteristic paradigm, its theoretical approaches and

Vassilis J. Inglezakis

2005-01-01

177

Volume reduction of ion exchange resin by a pyrolysis technique  

Microsoft Academic Search

Volume reduction techniques, such as incineration and acid digestion, of spent ion exchange resins from nuclear power plants are being developed with a view toward reducing radioactive waste volume and also making the final waste form more stable. The authors chose pyrolysis as a technique that can be done at low operating temperatures and low gas flow rates in a

M. Matsuda; K. Funabashi; S. Uchida; M. Kikuchi

1985-01-01

178

Ion exchange pretreatment of alkaline radwaste for cesium removal  

Microsoft Academic Search

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

Bibler

1994-01-01

179

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

180

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

181

EVALUATING ION EXCHANGE FOR REMOVING RADIUM FROM GROUNDWATER  

EPA Science Inventory

This article focuses on the results of bench and pilot-scale studies of ion exchange processes for radium removal from groundwater in Lemont, Ill. atch and column studies indicated a very high resin selectivity for radium compared with common cations. xhaustion-regeneration studi...

182

EVALUATING ION EXCHANGE FOR REMOVING RADIUM FROM GROUNDWATER  

EPA Science Inventory

This article, the second in a series, focuses on the results of bench- and pilot-scale studies of ion exchange processes for radium removal from groundwater in Lemont, Ill. Batch and column studies indicated a very high resin selectivity for radium compared with common cations. E...

183

New Advances in Catalysis by Ion-exchange Resins  

Microsoft Academic Search

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

N G Polyanskii; V K Sapozhnikov

1977-01-01

184

Dissociation of Methylamine Molecule Ions Formed in Charge Exchange Collisions with Positive Ions.  

National Technical Information Service (NTIS)

Mass spectra of methylamine were obtained after charge exchange with slow positive ions, and the intensities of the peaks were plotted as a function of the energy absorbed by the molecule during the charge exchange. The curves are integrated to give the e...

H. Sjogren

1965-01-01

185

Exchange of Th, U and Pu on Macroporous Ion Exchange Resins.  

National Technical Information Service (NTIS)

Absorption of Th, U and Pu on macroporous ion exchangers, Amberlyst 15 (cationic) and Amberlyst A-26 (anionic) were studied in nitric acid solutions and the results were found comparable with those on their microreticular counter parts, Dowex 50x8 and Dow...

M. N. Nadkarni P. C. Mayankutty N. S. Pillai S. S. Shinde

1977-01-01

186

Formulation and method for improved ion exchange in zeolites and related aluminosilicates using polymer solutions  

US Patent & Trademark Office Database

Among other things, this disclosure provides a method for exchanging cations in an aluminosilicate. The method includes combining, in an exchange solvent and under ion exchange conditions, an ion-exchangeable aluminosilicate having a first cation associated therewith as a counter ion and a second cation source, to provide a mixture that includes the ion-exchanged aluminosilicate which includes the second cation associated therewith as a counter ion. Suitable exchange solvents include polyalkylene oxide glycols, polyalkylene oxide glycol monoethers, polyalkylene oxide glycol diethers, or any combination thereof.

2012-07-17

187

Charge-exchange plasma generated by an ion thruster  

NASA Technical Reports Server (NTRS)

The use of high voltage solar arrays greatly reduces or eliminates power processing requirements in space electric propulsion systems. This use also requires substantial areas of solar array to be at high positive potential relative to space and most of the spacecraft. The charge exchange plasma conducts electrons from the ion beam to such positive surfaces, and thereby electrically load the high voltage solar array. To evaluate this problem, the charge-exchange plasma generated by an ion beam was investigated experimentally. Based upon the experimental data, a simple model was derived for the charge-exchange plasma. This model is conservative in the sense that both the electron/ion density and the electron current density should be equal to, or less than, the preducted value for all directions in the hemisphere upstream of the ion beam direction. Increasing the distance between a positive potential surface (such as a high voltage solar array) and the thruster is the simplest way to control interactions. Both densities and currents vary as the inverse square of this distance.

Kaufman, H. R.

1975-01-01

188

Ion-exchange chromatography of proteins near the isoelectric points  

Microsoft Academic Search

The retention and the resolution of ?-lactoglobulin A and B (LgA, LgB) were investigated with various ion-exchange chromatography media. The number of sites involved in the retention (adsorption) decreased as the mobile phase pH approached the isoelectric points pI (=5.1–5.2). However, even at pH 5.2 both LgA and LgB were retained on anion- and cation-exchange chromatography columns. The separation (resolution)

Shuichi Yamamoto; Takashi Ishihara

1999-01-01

189

Syntesis of lanthanum zirconate hydrosols by the ion exchange method  

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

190

Syntesis of lanthanum zirconate hydrosols by the ion exchange method  

Microsoft Academic Search

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

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

2011-01-01

191

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

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

192

Quantitative Analysis of Water Confined in Ion-Exchanged Zeolites  

NASA Astrophysics Data System (ADS)

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

Wang, J.; Neuhoff, P. S.

2009-12-01

193

Detoxification of lignocellulose hydrolysates with ion-exchange resins.  

PubMed

Lignocellulose hydrolysates contain fermentation inhibitors causing decreased ethanol production. The inhibitors include phenolic compounds, furan aldehydes, and aliphatic acids. One of the most efficient methods for removing inhibiting compounds prior to fermentation is treatment of the hydrolysate with ion-exchange resins. The performance and detoxification mechanism of three different resins were examined: an anion exchanger, a cation exchanger, and a resin without charged groups (XAD-8). A dilute acid hydrolysate of spruce was treated with the resins at pH 5.5 and 10.0 prior to ethanolic fermentation with Saccharomyces cerevisiae. In addition to the experiments with hydrolysate, the effect of the resins on selected model compounds, three phenolics (vanillin, guaiacol, and coniferyl aldehyde) and two furan aldehydes (furfural and hydroxymethyl furfural), was determined. The cation exchanger increased ethanol production, but to a lesser extent than XAD-8, which in turn was less effective than the anion exchanger. Treatment at pH 10.0 was more effective than at pH 5.5. At pH 10.0, the anion exchanger efficiently removed both anionic and uncharged inhibitors, the latter by hydrophobic interactions. The importance of hydrophobic interactions was further indicated by a substantial decrease in the concentration of model compounds, such as guaiacol and furfural, after treatment with XAD-8. PMID:11963864

Nilvebrant, N O; Reimann, A; Larsson, S; Jönsson, L J

2001-01-01

194

Innovative uses of specialy ion exchange resins provide new cost-effective options for metals removal  

Microsoft Academic Search

Ion exchange treatment of water for boiler and process systems is a documented, proven unit operation. The recent development of a group of novel resins had expanded the potential use of ion exchange processes to a new range of applications. By applying a different functional group onto the traditional styrene\\/divinylbenzene polymer backbone, ion exchange technology becomes a cost-effective treatment option

George Totura

1996-01-01

195

Time-cycled inverse ratio ventilation does not improve gas exchange during anaesthesia  

Microsoft Academic Search

Inverse ratio ventilation (IRV) has been reported to improve oxygenation at lower peak airway pressures in patients with respiratory\\u000a failure. Therefore we hypothesised that IRV might also improve oxygen exchange during anaesthesia. Conventional ratio ventilation\\u000a (CRV) and IRV were compared in 24 low-risk surgical patients who were paralysed and whose lungs were ventilated with air\\/02 by a non-rebreathing circuit and

W. A. Tweed; T. L. Lee

1991-01-01

196

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

PubMed

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

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

2004-06-11

197

Rem nut ion exchange plus struvite precipitation process.  

PubMed

Nutrients control technologies from wastewater are based on destructive technologies which defer the problem fromthe diluted liquid-phase (effluent) to a more concentrated waste (sludge) in the case of phosphates, or to nitrogen gas and/or volatile compounds in the case of ammonia. The REM NUT process allows for simultaneous removal of phosphate and ammonium ions by selective ion exchange and recovery by chemical precipitation in the form of struvite (magnesium ammonium phosphate) from the spent exchangers regeneration eluates. In the paper revised versions of the REM NUT process, i.e., P-driven layouts, are presented and cost effectiveness is compared to chemical precipitation based on the use of ferric chloride. PMID:11804353

Liberti, L; Petruzzelli, D; De Florio, L

2001-11-01

198

Correlating exchange bias with magnetic anisotropy in ion-beam bombarded NiFe\\/Mn-oxide bilayers  

Microsoft Academic Search

The exchange bias field dependence on the Mn-oxide and its microstructure in NiFe\\/Mn-oxide bilayers was investigated. Transmission electron microscopy results have shown that the bilayer bottom consisted of either ?-Mn, rocksalt MnO, or a composite of tetragonal Mn3O4+MnO, depending on the ratio of O2\\/Ar used during dual ion-beam deposition. Magnetometry results at 5 K indicate that the exchange bias field

K.-W Lin; J.-Y. Guo; T.-J. Chen; H. Ouyang; E. Vass; J. van Lierop

2008-01-01

199

Correlating exchange bias with magnetic anisotropy in ion-beam bombarded NiFe\\/Mn-oxide bilayers  

Microsoft Academic Search

The exchange bias field dependence on the Mn-oxide and its microstructure in NiFe\\/Mn-oxide bilayers was investigated. Transmission electron microscopy results have shown that the bilayer bottom consisted of either alpha-Mn, rocksalt MnO, or a composite of tetragonal Mn3O4+MnO, depending on the ratio of O2\\/Ar used during dual ion-beam deposition. Magnetometry results at 5 K indicate that the exchange bias field

K.-W. Lin; J.-Y. Guo; T.-J. Chen; H. Ouyang; E. Vass; J. van Lierop

2008-01-01

200

Total dissolved solids removal by electrochemical ion exchange (EIX) process  

Microsoft Academic Search

In the present investigation, synthetic wastewater was prepared by the addition of required amount of salts into deionized water. Their performance, on removal of Cl?, SO42?, PO43?, Ca2+, Fe2+ and Mg2+ in laboratory scale plate and frame type electrochemical ion exchange (EIX) cells, were evaluated under varying operating conditions. Ruthenium dioxide coated titanium plates (RuO2\\/Ti) were used as anode and

C. Ahmed Basha; Pranab Kumar Ghosh; G. Gajalakshmi

2008-01-01

201

Ion exchange and adsorption on low rank coals for liquefaction  

SciTech Connect

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

Vorres, K.S.

1995-08-01

202

Ion exchange-high-performance liquid chromatography (IEX-HPLC).  

PubMed

The ion exchange-high-performance liquid chromatography is a high-throughput analytical method that allows to determine the charge profile of purified antibodies. Here, we describe the preparation of the samples, chromatographic conditions to be used (buffer preparation, salt gradient, quantity injected, flow rate, run time, column suitability, etc.), validity of the analysis, and integration of the chromatogram in order to calculate the proportion of the different isoforms. PMID:24515485

Corbier, Marie; Schrag, Delphine; Raimondi, Sylvain

2014-01-01

203

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

SciTech Connect

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

Duncan, J.B.

1998-08-25

204

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

205

Mechanistic model of retention in protein ion-exchange chromatography  

Microsoft Academic Search

A mechanistic model is developed to describe the retention of proteins in ion-exchange chromatography, as a simplified version of a more elaborate colloidal model within which retention is related to protein and stationary-phase structural and functional parameters and eluent composition. The protein parameters are the size and net charge, while incorporation of stationary-phase properties, namely the surface charge density and

Charles M. Roth; Klaus K. Unger; Abraham M. Lenhoff

1996-01-01

206

Ion exchange of ammonium in natural and synthesized zeolites  

Microsoft Academic Search

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

Yifei Wang; Feng Lin; Wenqin Pang

2008-01-01

207

Sorption characteristics of uranium onto composite ion exchangers  

Microsoft Academic Search

The composite ion exchangers were tested for their ability to remove UO2\\u000a2+ from aqueous solutions. Polyacrylonitrile (PAN) composites having natural zeolite, clinoptilolite, and synthetic zeolite, zeolite X, were used as an adsorbents. The influences of pH, U(VI) concentration, temperature and contact time on the sorption behavior of U(VI) were investigated in order to gain a macroscopic understanding of the

S. Akyil; M. A. A. Aslani; M. Eral

2003-01-01

208

Ammonium removal from digested sludge liquors using ion exchange  

Microsoft Academic Search

Liquors arising from the dewatering of digested sludge typically contain ammonium levels in the range 200–700mgl?1 NH4+-N. These liquors are frequently recycled to the head of the wastewater treatment works (WwTW) untreated and can constitute >25% of the total nitrogen load entering the works at inlet. This paper investigates the use of a clay-based material, MesoLite, as an ion exchange

A. Thornton; P. Pearce; S. A. Parsons

2007-01-01

209

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

Microsoft Academic Search

We show that collective Thomson scattering (CTS) holds the potential to become a new diagnostic principle for measurements of the fuel ion ratio, nT\\/nD, in ITER. Fuel ion ratio measurements will be important for plasma control and machine protection in ITER. Measurements of ion cyclotron structures in CTS spectra have been suggested as the basis for a new fuel ion

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

2012-01-01

210

Evaluation of Elution Parameters for Cesium Ion Exchange Resins  

SciTech Connect

Cesium ion exchange is one of the planned processes for treating and disposing of waste at the U.S. Department of Energy Hanford Site. Radioactive supernatant liquids from the waste tanks will undergo ultrafiltration, followed by cesium ion exchange using a regenerable organic ion exchange resin. Two resins, SuperLig?644 and a Resorcinol-formaldehyde resin are being evaluated for cesium removal and cesium elution characteristics. The main purpose of this study is to optimize the cesium elution to provide a resin which after undergoing elution would meet the U.S. Department of Energy/Office of River Protection Project-Waste Treatment Plant processing and resin disposal criteria. Columns of each resin type were loaded to greater or equal to 90% breakthrough with a Hanford waste stimulant and eluted with nitric acid. The temperature, flow rate and nitric acid concentration were varied to determine the optimal elution conditions. Temperature and eluant flow rate were the most important elution parameters. As would be predicted based upon kinetic consideration alone, decreasing the eluant flow rate and increasing the temperature provided the optimal elution conditions. Varying the nitric acid concentration did not have a significant effect on the elution; however, elutions performed using both high acid concentration (1M) and elevated temperature (45 C) resulted in resin degradation, causing gas generation and resin bed disruption.

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

2006-08-28

211

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

212

A novel pulse isotopic exchange technique for rapid determination of the oxygen surface exchange rate of oxide ion conductors.  

PubMed

We demonstrate the use of a novel pulse (18)O-(16)O isotopic exchange technique for the rapid determination of the oxygen surface exchange rate of oxide ion conductors while simultaneously providing insight into the mechanism of the oxygen exchange reaction, which contributes to the efficient development of devices incorporating these solids, such as solid oxide fuel cells and oxygen transport membranes. PMID:19851540

Bouwmeester, Henny J M; Song, Chunlin; Zhu, Jianjun; Yi, Jianxin; van Sint Annaland, Martin; Boukamp, Bernard A

2009-11-14

213

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

SciTech Connect

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

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

1991-10-01

214

Ion exchange studies on natural and modified zeolites and the concept of exchange site accessibility  

Microsoft Academic Search

In the present study natural and Na-rich form of clinoptilolite are examined, in respect to ion exchange of Pb2+, Cu2+, Cr3+, and Fe3+. Equilibrium and kinetic studies performed, under the same normality (0.01 N). Equilibrium studies demonstrate that Na+ enrichment of clinoptilolite is beneficial in respect to metal uptake for all metals, except Cr3+, which is shown to have the same

Vassilis J. Inglezakis; Maria M. Loizidou; Helen P. Grigoropoulou

2004-01-01

215

Ammonia Removal from Agricultural Runoff and Secondary Effluents by Selected Ion Exchange.  

National Technical Information Service (NTIS)

A selective ion exchange process was developed for the removal of ammonia nitrogen from wastewater. The process employs a natural zeolite, clinoptilolite, which is selective for ammonium ions in the presence of sodium, magnesium, and calcium ions. Regener...

1969-01-01

216

Ion time-of-flight determinations of doubly to singly ionized mercury ion ratios from a mercury electron bombardment discharge  

NASA Technical Reports Server (NTRS)

Doubly to singly charged mercury ion ratios in electron bombardment ion thruster exhaust beams have been determined as functions of bombardment discharge potential, thrust beam current, thrust beam radial position, acceleration-deceleration voltage ratio, and propellant utilization fraction. A mathematical model for two-step ionization processes has been derived, and calculated ion ratios are compared to observed ratios. Production of Hg(++) appears to result primarily from sequential ionization of Hg(+) in the discharge. Experimental and analytical results are presented, and design, construction, and operation features of an electrostatic deflection ion time-of-flight analyzer for the determination of the above-mentioned ratios are reviewed.

Sellen, J. M., Jr.; Kemp, R. F.; Hall, D. F.

1973-01-01

217

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

Microsoft Academic Search

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

T. C. Jorgensen; L. R. Weatherley

2003-01-01

218

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(2+) to proton density ratio increased from 2.5 percent in the solar wind to about 4 percent about 1 hr before closest approach after which time it decreased to about 1 percent. Abrupt increases in this ratio from 2.5 to 4.5 percent were also observed in the beginning and near the end of the so-called Mystery Region. 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(2+) 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(2+).

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

1991-01-01

219

Modeling the ion transfer and polarization of ion exchange membranes in bioelectrochemical systems.  

PubMed

An explicit numerical model for the charge balancing ion transfer across monopolar ion exchange membranes under conditions of bioelectrochemical systems is presented. Diffusion and migration equations have been solved according to the Nernst-Planck Equation and the resulting ion concentrations, pH values and the resistance values of the membrane for different conditions were computed. The modeling results underline the principle limitations of the application of ion exchange membranes in biological fuel cells and electrolyzers, caused by the inherent occurrence of a pH-gradient between anode and cathode compartment, and an increased ohmic membrane resistance at decreasing electrolyte concentrations. Finally, the physical and numerical limitations of the model are discussed. PMID:19349214

Harnisch, Falk; Warmbier, Robert; Schneider, Ralf; Schröder, Uwe

2009-06-01

220

Origin of Selectivity in Tunnel Type Inorganic Ion Exchangers  

SciTech Connect

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

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

2004-03-29

221

High Performance DNA Purification using a Novel Ion Exchange Matrix  

PubMed Central

Ion exchange chromatography has emerged as a reliable alternative to classic CsCl-ethidium bromide gradients for isolating nucleic acids of the highest purity. A plasmid purification method based on a unique anion exchange membrane (IEXM) was developed for the production of superior quality plasmids. This method was simpler and more efficient than conventional bead-based methods. Plasmids were extracted from bacterial cells through alkaline lysis. The crude lysate was clarified by a sequential filtration device that not only removed cell debris but micellar aggregates as well. The clarified lysate was mixed with an extraction solution and loaded into a spin column containing IEXM. Binding, washing, and elution conditions were optimized to achieve efficient isolation of plasmids from the impurities. IEXM had an exceedingly high dynamic binding capacity, excellent selectivity, and a near 100% recovery for plasmids. The binding capacity for pUC19 was 2.93 mg/cm3 of IEXM, which is several times greater than the values for conventional ion exchange beads. The superior selectivity of the method was reflected in the extremely low levels of endotoxin, and thus it is well-suited for critical applications in eukaryotic systems.

Yang, Yu; Hebron, Haroun R.; Hang, Jun

2008-01-01

222

Diffusional transport of ions in plasticized anion-exchange membranes.  

PubMed

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

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

2011-05-19

223

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

224

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

Microsoft Academic Search

An extensive search of the literature has been made for ion exchange data on smectites, certain zeolites and basalt. The data are in the form of thermodynamic equilibrium constants, corrected selectivity coefficients, and distribution coefficients. Room temperature alkali and alkaline earth metal cation ion exchange data for smectites are extensive. Correlation between the exchange free energies of alkali metal cations

1980-01-01

225

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

226

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

227

Ion Exchange Testing with SRF Resin FY2012  

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. 3.0 , which was prepared and approved in response to the Test Specification 24590 PTF-TSP-RT-09-002, Rev. 0 (Lehrman 2010) and Test Exception 24590 PTF TEF RT-11-00003, Rev. 0 (Meehan 2011). This testing focused on column tests evaluating the impact of elevated temperature on resin degradation over an extended period of time and batch contacts evaluating the impact on Cs loading over a broad range of sodium concentrations (0.1 to 5 M). These changes may be required to alleviate post-filtration precipitation issues and broaden the data range of SRF resin loading under the conditions expected with the new equipment and process changes.

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

2013-06-11

228

Synthesis of Di- and trivalent. beta. -aluminas by ion exchange  

SciTech Connect

Many of the mono- di-, and trivalent cations in the periodic chart diffuse rapidly in the ..beta..-alumina structure. ..beta..-Aluminas containing multivalent cations can be synthesized by ion exchange reactions starting with the sodium form of the compound. These facile reactions make it possible to prepare a wide variety of ..beta..-alumina compositions, many of which are metastable and inaccessible by normal synthetic means. This paper describes the methods used to synthesize multivalent ..beta..-aluminas and the preparation of a number of specific transition metal and lanthanide forms of these compounds.

Sattar, S.; Ghosal, B.; Underwood, M.L.; Mertwoy, H.; Saltzberg, M.A.; Frydrych, W.S.; Rohrer, G.S.; Farrington, G.C.

1986-11-15

229

UPTAKE OF METAL IONS BY A NEW CHELATING ION-EXCHANGE RESIN. PART 4 : KINETICS  

Microsoft Academic Search

The rate of uptake of several actinide ions [Am(III), U(VI), Th(IV), Np(IV) and Pu(IV)] and of some transition-metal ions [Co(II), Zn(II), Fe(III) and Cr(III)] at tracer concentration level, from solutions of various compositions, by the new chelating ion-exchange resin, Diphonix, has been investigated. Diphonix is a polyfunctional resin containing sulfonic and gem-diphosphonic acid groups chemically bonded in a styrene-divinylbenzene polymeric

R. Chiarizia; E. P. Horwitz; S. D. E. P. Alexandratos

1994-01-01

230

Electrically switched cesium ion exchange. FY 1996 annual report  

SciTech Connect

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

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

1996-12-01

231

Thermodynamics of ion exchange between clinoptilolite and aqueous solutions of na +/k + and na +/ca 2+  

NASA Astrophysics Data System (ADS)

To provide a thermodynamic basis for understanding zeolite-water interactions in geologic systems, ion-exchange experiments were conducted at 25°C between clinoptilolite, which is the predominant zeolite mineral in altered pyroclastic and volcaniclastic rocks and aqueous mixtures of Na +/K + and Na +/Ca 2+. Isotherm points were obtained by equilibrating Na-clinoptilolite, which was prepared from clinoptilolite-rich tuff from Death Valley Junction, California, USA and Na +/K + and Na +/Ca 2+ chloride solutions having different ionic concentration ratios, but constant total normalities of 0.5, 0.05, or 0.005 N. The experimental data were interpreted using a Margules thermodynamic formulation for zeolite solid solutions, coupled with the Pitzer model for aqueous activity coefficients. The isotherm data for 0.5 N Na +/K + and Na +/Ca 2+ solutions were used to derive equilibrium constants and Gibbs free energies for the ion-exchange reactions, as well as parameters for the Margules model. Using the same parameters derived from the 0.5 N data, isotherms were calculated for the 0.05 and 0.005 N solutions. The predicted values agree very well with experimental data, including other data at 0.05 N solution concentration with nitrate as the supporting anion. The results of this study indicate that a Margules solid solution model for zeolites, coupled with an activity coefficient model for aqueous solutions (e.g., Pitzer model), can successfully describe and predict binary ion-exchange equilibria between aqueous solutions and the zeolite mineral clinoptilolite over a wide range of solution composition and concentration, and may provide a foundation for quantitative understanding of ion-exchange equilibria in multicomponent geochemical systems.

Pabalan, Roberto T.

1994-11-01

232

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

SciTech Connect

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

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

2009-01-01

233

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

SciTech Connect

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

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

2009-09-10

234

Metal ion coordination studies on a silica-based ion exchange resin before and after heating.  

SciTech Connect

Work designed to assess the potential of using a single material to sorb highly charged metal ions from aqueous solution and then microencapsulate and chemical fix those sorbed metal ions in vitreous silica is described. The basis for these studies is a chemically functionalized porous silica that is termed Diphosil. Diphosil was created by Chiarizia and coworkers (Solv. Extr. Ion Exch. 1996, 14(6), 1977-1100) as an ion exchange resin that strongly sorbs actinide and other highly charged metal ions from acid solutions. We have determined the maximum metal ion loading for Diphosil and shown that it sorbs trivalent ions from concentrated phosphoric acid. Using FT-IR analysis, we have shown that heating metal ion-loaded Diphosil in air converts its organic content primarily into carbon dioxide and water vapor. We have carried out studies on luminescence dynamics and spectroscopy, powder x-ray diffraction, and optical microscopy of metal ion-loaded Diphosil prior to and following heating in air. All of the results of our investigations are consistent with microencapsulation and chemical fixation of metal ions sorbed into Diphosil when that material is heated to 1273 K. In consequence, Diphosil is a promising basis for a single material approach to reducing nuclear waste volume by removing longlived alpha emitters from high level liquid radioactive waste and generating a vitreous silica nuclear waste form for the removed radionuclides that is suitable for geologic disposal.

Beitz, J. V.; Williams, C. W.; Chemistry

2001-07-31

235

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

236

Ion exchange chromatography and mass spectrometric methods for analysis of cadmium-phytochelatin (II) complexes.  

PubMed

In this study, in vitro formed Cd-phytochelatin (PC2) complexes were characterized using ion exchange chromatography (IEC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The ratio of both studied compounds as well as experimental conditions were optimized. The highest yield of the complex was observed under an applied concentration of 100 µg·mL(-1) PC2 and 100 µg·mL(-1) of CdCl2. The data obtained show that IEC in combination with MALDI-TOF is a reliable and fast method for the determination of these complexes. PMID:23538727

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

2013-04-01

237

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

PubMed Central

In this study, in vitro formed Cd-phytochelatin (PC2) complexes were characterized using ion exchange chromatography (IEC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The ratio of both studied compounds as well as experimental conditions were optimized. The highest yield of the complex was observed under an applied concentration of 100 µg·mL?1 PC2 and 100 µg·mL?1 of CdCl2. The data obtained show that IEC in combination with MALDI-TOF is a reliable and fast method for the determination of these complexes.

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

2013-01-01

238

CLASSICAL AREAS OF PHENOMENOLOGY: Modelling of graded index waveguide fabricated by ion exchange on Er3+ doped glass  

NASA Astrophysics Data System (ADS)

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

Shao, Gong-Wang; Jin, Guo-Liang

2009-03-01

239

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

NASA Technical Reports Server (NTRS)

Experimental anion permselective membranes were prepared and tested for their suitability as cell separators in a chemical redox power storage system being developed at NASA-Lewis Research Center. The goals of long-term (1000 hr) oxidative and thermal stability at 80 C in FeCl3 and CrCl3 electrolytes were met by most of the weak base and strong base amino exchange groups considered in the program. Good stability is exhibited by several of the membrane substrate resins. These are 'styrene' divinylbenzene copolymer and PVC film. At least four membrane systems produce strong flexible films with electrochemical properties (resistivity, cation transfer) superior to those of the 103QZL, the most promising commercial membrane. The physical and chemical properties of the resins are listed.

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

1975-01-01

240

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

SciTech Connect

Approximately 73 m{sup 3} of heterogeneous solid material, ''sludge,'' (upper bound estimate, Packer 1997) have accumulated at the bottom of the K Basins in the 100 K Area of the Hanford Site. This sludge is a mixture of spent fuel element corrosion products, ion exchange materials (organic and inorganic), graphite-based gasket materials, iron and aluminum metal corrosion products, sand, and debris (Makenas et al. 1996, 1997). In addition, small amounts of polychlorinated biphenyls (PCBs) have been found. These small amounts are significant from a regulatory standpoint. Ultimately, it is planned to transfer the K Basins sludge to the Hanford double shell tanks (DSTs). Chemical pretreatment is required to address criticality issues and the destruction or removal of PCBs before the K Basin sludge can be transferred to the DSTs. Eleven technologies have been evaluated (Papp 1997) as potential pretreatment methods. Based on the evaluations and engineering studies and limited testing, Fluor Daniel Hanford recommended solvent washing of the K Basin sludge, followed by nitric acid dissolution and, potentially, peroxide addition (FDH 1997). The solvent washing (extraction) and peroxide addition would be used to facilitate PCB removal and destruction. Following solvent extraction, the PCBs could be distilled and concentrated for disposal as a low-level waste. The purpose of the work reported here was to continue investigating solvent extraction, first by better identifying the ion exchange materials in the actual sludge samples and then evaluating various solvents for removing the PCBs or possibly dissolving the resins. This report documents some of the process knowledge on ion exchange materials used and spilled in the K Basins and describes the materials identified from wet sieving KE Basin floor and canister sludge and the results of other analyses. Several photographs are included to compare materials and illustrate material behavior. A summary of previous tests on solvent extraction of PCB surrogates from simulant K Basin sludge is also given.

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

1999-04-10

241

Electrical Conductivity of Ion Exchange Membranes and the Inhomogeneity of Their Structure.  

National Technical Information Service (NTIS)

The electrical conductivity of a number of ion exchange membranes is studied. Topics discussed include iogenic groups, production technology, total exchange capacity, the nature of the concentration, and the temperature of the solution. It is shown that t...

V. K. Varentsov M. V. Pevnitskaya

1974-01-01

242

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

243

Low-level liquid waste decontamination by ion exchange  

SciTech Connect

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

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

1991-12-01

244

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

PubMed

The scope of this study was the removal of ammonium by ion exchange from simulated wastewater. The study looks at the effect of organics upon ammonium ion exchange equilibrium uptake. The ion exchangers included a natural zeolite clinoptilolite, and two polymeric exchangers, Dowex 50w-x8, and Purolite MN500. The organic compounds studied included citric acid and a number of proteins. The traditional method for removal of ammonium and organic pollutants from wastewater is biological treatment, but ion exchange offers a number of advantages including the ability to handle shock loadings and the ability to operate over a wider range of temperatures. The results show that in most of the cases studied, the presence of organic compounds enhances the uptake of ammonium ion onto the ion exchangers. PMID:12697216

Jorgensen, T C; Weatherley, L R

2003-04-01

245

Use of energy-dispersive x-ray fluorescence analysis in clay mineral ion exchange studies  

Microsoft Academic Search

A rapid, reliable, semiquantitative method for following ion exchange processes in clay minerals is described. An energy-dispersive x-ray fluorescence technique is used. The completeness of the exchange process for the clay mineral montmorillonite was investigated for the ions Rb\\/sup +1\\/, Sr\\/sup +2\\/, and Y\\/sup +3\\/. Samples of clay, suspended on asbestos, were packed in an ion exchange column and solutions

J. F. Mucci; R. L. Stearns

1977-01-01

246

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

SciTech Connect

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

Not Available

1994-04-01

247

Strong anion-exchange liquid chromatography coupled with isotope ratio mass spectrometry using a Liquiface interface.  

PubMed

The introduction of liquid chromatography coupled with isotope ratio mass spectrometry (LC/IRMS) as an analytical tool for the measurement of isotope ratios in non-volatile analytes has somewhat simplified the analytical cycle from sample collection to analysis mainly due to the avoidance of the extensive sample processing and derivatisation that were necessary for gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Here we test the performance of coupling strong anion exchange to IRMS using only the second commercially available interface; the Liquiface. The system was modified from installation specification to improve peak resolution in the interface and maintain peak separation from the column to the mass spectrometer. The system performance was assessed by the determination of sensitivity, accuracy and precision attained from carbohydrate separations. The system performed satisfactorily after modifications, resulting in maintenance of peak resolution from column to mass spectrometer. The sensitivity achieved suggested that approximately 150 ng carbon could be analysed with acceptable precision (<0.3 per thousand). Accuracy was maintained in the interface as determined by correlation with offline techniques, resulting in regression coefficient of r(2) = 0.98 and a slope of 0.99. The average precision achieved for the separation of seven monosaccharides was 0.36 per thousand. The integration of a carbonate removal device limited the effect of background carbon perturbations in the mass spectrometer associated with eluent gradients, and the coupling of strong anion-exchange chromatography with IRMS was successfully achieved using the Liquiface. PMID:20499320

Morrison, Douglas J; Taylor, Karen; Preston, Tom

2010-06-30

248

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

Microsoft Academic Search

Assessing the suitability of Yucca Mtn., NV as a potential repository for high-level nuclear waste requires the means to simulate ion-exchange behavior of zeolites. Vanselow and Gapon convention cation-exchange models have been added to geochemical modeling codes EQ3NR\\/EQ6, allowing exchange to be modeled for up to three exchangers or a single exchanger with three independent sites. Solid-solution models that are

B. E. Viani; C. J. Bruton

1992-01-01

249

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

250

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

SciTech Connect

Sorption of uranyl ions by epoxy amine ampholytes with N-monomethylenephosphonic acid groups modified with pyridine or quaternary ammonium groups was studied under dynamic conditions. Heterocyclic nitrogen favors sorption of uranyl ion from fluoride, sulfate, and fluoride-sulfate solutions. The ESR studies of mono- and bimetallic forms of nitrogen-containing ampholytes with copper(II) as paramagnetic marker revealed the characteristics of uranium(VI) interaction with cation- and anion-exchange groups and its dependence on the fluoride content in solution.

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

1995-03-01

251

Effect of hydroxyl and nitrate ions on the sorption of ammonium ions by sulphonic cation exchangers  

Microsoft Academic Search

The sorption of ammonium ions and ammonia by the H+ form of sulphonic acid cation exchangers Amberlite 252, Lewatit 2629 and Relite C 360 from a solution containing NH4NO3 in the range of 0 to 0.214 equ\\/L and NH3 in the range of 0.353 to 0 equ\\/L was investigated to establish the possibility of their application for the recovery of

A. Ancuta; D. Kaušp; A. Gefenien; J. Snukiškis; E. Vasilevi

2005-01-01

252

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

PubMed

The thermal effect on retention and separation selectivity of inorganic anions and aromatic sulfonate ions in anion-exchange chromatography is studied on a quaternized styrene-divinylbenzene copolymer anion-exchange column in the temperature range of 40-120 °C using superheated water chromatography. The selectivity coefficient for a pair of identically charged anions approaches unity as temperature increases provided the ions have the same effective size, such that the retention of an analyte ion decreases with an increase in temperature when the analyte ion has stronger affinity for the ion-exchanger than that of the eluent counterion, whereas it increases when it has weaker affinity. The change in anion-exchange selectivity with temperature observed with superheated water chromatography has been discussed on the basis of the effect of temperature on hydration of the ions. At elevated temperatures, especially in superheated water, the electrostatic interaction or association of the ions with the fixed ion in the resin phase becomes a predominant factor resulting in a different separation selectivity from that obtained at ambient temperature. PMID:22614168

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

2012-07-01

253

Extractive lactic acid fermentation using ion-exchange resin.  

PubMed

Lactic acid fermentation is an end-product-inhibited reaction. The restriction imposed by lactic acid on its fermentation can be avoided by extractive fermentation techniques. Studies were performed by attaching an ion-exchange resin packed column with a 2-L fermentor for separation of lactic acid. The fermentation, in a conventional batch mode, resulted in a lactic acid yield of 0.828 g . g(-1) and a lactic acid productivity of 0.313 g . L(-1) . h(-1). However, these could be further enhanced to 0.929 g . g(-1) and 1.665 g . L(-1) . h(-1) by extractive fermentation techniques. The effect of temperature on extractive fermentation was remarkable and has been included in this work. PMID:18600989

Srivastava, A; Roychoudhury, P K; Sahai, V

1992-03-15

254

Ion exchange resin bead decoupled high-pressure electroosmotic pump.  

PubMed

We describe an electroosmotic pump (EOP) that utilizes a cation exchange resin bead as the electric field decoupler. The resin bead serves as a electrical grounding joint without fluid leakage, thus eliminating electrolytic gas interference from the flow channels. The arrangement is easy to practice from readily available components, displays a very low electrical resistance, and is capable of bearing high backpressure (at least 3200 psi). We use a silica xerogel column as the EOP element to pump water and demonstrate a complete capillary ion chromatograph (CIC), which uses a similar bead based microelectrodialytic generator (micro-EDG) to generate a KOH eluent from the pumped water. We observed good operational stability of the complete arrangement over long periods. PMID:19449862

Yang, Bingcheng; Zhang, Feifang; Liang, Xinmiao; Dasgupta, Purnendu K; Liu, Shaorong

2009-06-15

255

Determination of biogenic amines in cheese by ion exchange chromatography.  

PubMed

A sensitive, fully automated method, yielding reproducible results, was developed for the determination of relevant biogenic amines in cheese. Histamine, tyramine, putrescine, cadaverine, tryptamine, agmatine, spermidine and spermine were separated in the ion exchanger of OSTION LG ANB column of the automatic amino acid analyser Mikrotechna 339 T. Elution was carried out at 60 degrees C using a system of two buffers. The samples were extracted and precipitated by trichloroacetic acid and purified, after removal of fat, by membrane filtration. The recovery for individual amines in cheese ranged between 86% and 108%. The detection limit was of 1-5 mg of the respective amine per 1 kg of cheese and the method was linear within the dose range of 0.1-10 micrograms (for tryptamine 0.5-10 micrograms). PMID:10702996

Standara, S; Veselá, M; Drdák, M

2000-02-01

256

Ion Exchange in Organic Solvents - (Part)I. Absorption of Thorium, Uranium and Plutonium by Macroreticular Ion Exchangers from Tri-N-Butyl Phosphate.  

National Technical Information Service (NTIS)

Absorption of thorium, uranium, plutonium and some fission products by macrorecticular ion exchange resins from tri-n-butyl phosphate solutions is investigated for the first time. Thorium, plutonium and the fission products are found to be preferentially ...

P. C. Mayankutty N. S. Pillai S. S. Shinde M. N. Nadkarni

1977-01-01

257

Study of the Behavior of Inorganic Ion Exchangers in the Treatment of Medium Active Effluents. Pt. 5. The Encapsulation of Inorganic Ion Exchangers in Cement.  

National Technical Information Service (NTIS)

This report describes some results obtained for a generic program of work for the Department of the Environment on the potential application of inorganic ion exchangers for the treatment of medium active effluents. The results from a preliminary investiga...

G. W. Beaven J. E. Cross E. W. Hooper

1988-01-01

258

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

259

Immobilization of Acetobacter aceti on cellulose ion exchangers: adsorption isotherms  

SciTech Connect

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

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

1986-08-01

260

Dielectronic recombination versus charge exchange: Electron capture by metastable ions  

NASA Astrophysics Data System (ADS)

In the case of He-like ions, dielectronic recombination ends in the population of Li-like core excited states. Likewise the charge-exchange collision process involving long-lived metastable He-like ions ends in Li-like core excited states. The observation of satellites 1s2l2l'-->1s22l'' and 1s23l'' leaves open a certain number of questions. The case of O6+(1s2s)3S1+H2, C4+(1s2s)3S1+H2, and N5+(1s2s)3S1+H2 is considered. The satellites are seen, unpolluted by parent transitions on the one hand, and on the other hand the parent transitions are observed. But a further test of the capture process is significant: the 4L to 4L optical transitions in the vacuum ultraviolet range. The n=4 satellites in oxygen and nitrogen coincide with the n=3 parent transitions.

Bliman, S.; Cornille, M.; Katsonis, K.

1994-10-01

261

REMOVAL OF URANIUM FROM DRINKING WATER BY ION EXCHANGE AND CHEMICAL CLARIFICATION  

EPA Science Inventory

A pilot demonstration was conducted of ion exchange and chemical clarification equipment for removing uranium from drinking water. Four commercial-type ion exchange columns and a prefiltering and regeneration solution system were constructed along with a pilot-scale chemical clar...

262

Nanomaterials-Enhanced Electrically Switched Ion Exchange Process for Water Treatment  

Microsoft Academic Search

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

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

2009-01-01

263

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

264

Ion Exchange Derived Precursor Materials for Deposition of WO 3 Electrochromic Films: Spectroscopic Investigations  

Microsoft Academic Search

The ion exchange route was first successfully used by Livage et al. for depositing WO3 films exhibiting reversible electrochromic effect. We report in this paper the preparation of a solid precursor material by chemically modifying this route. The short lived ion exchange derived sol on addition of H2O2 and acetic acid on further processing, yields a solid precursor material with

S. A. Agnihotry; N. Sharma; M. Deepa

2002-01-01

265

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

266

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

267

Casting Granular Ion Exchange Resins with Medium-Active Waste in Cement.  

National Technical Information Service (NTIS)

Medium active waste from nuclear power stations in Sweden is trapped in granular ion exchange resins. The resin is mixed with cement paste and cast in a concrete shell which is cubic and has an edge dimension of 1.2 m. In some cases the ion exchange cemen...

O. Beijer

1980-01-01

268

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

Microsoft Academic Search

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

2010-01-01

269

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

Microsoft Academic Search

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

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

1998-01-01

270

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

Microsoft Academic Search

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

R. Christell; S. Forberg; T. Westermark

1961-01-01

271

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

272

Ion exchange and adsorption equilibrium studies on clinoptilolite, bentonite and vermiculite  

Microsoft Academic Search

In the present paper three natural minerals used in many industrial and environmental applications namely zeolite clinoptilolite and the clays bentonite and vermiculite are studied by utilising ion exchange and adsorption. In particular, the Dubinin–Astakhov adsorption isotherm is used modified by introducing a solubility-normalized adsorption potential for studying the ion exchange process. The equation, is applied in experimental isotherms in

V. J. Inglezakis; M. Stylianou; M. Loizidou

2010-01-01

273

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

SciTech Connect

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

Maxwell, III, S L

1988-01-01

274

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

National Technical Information Service (NTIS)

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

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

1984-01-01

275

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

Microsoft Academic Search

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

Simon A Parsons

2000-01-01

276

THREE-DIMENSIONAL THERMAL MODELING ANALYSIS OF CST MEDIA FOR THE SMALL ION EXCHANGE PROJECT  

Microsoft Academic Search

The Small Column Ion Exchange (SCIX) project is designed to accelerate closure of High Level Waste (HLW) tanks at the Savannah River Site (SRS). The SRS tanks store HLW in three forms: sludge, saltcake, and supernate. An in-tank ion exchange process is being designed to treat supernate and dissolved saltcake waste. Through this process, radioactive cesium from the salt solution

S. Lee; W. King

2011-01-01

277

A STUDY OF THORIUM COMPLEXING BY MEANS OF ION EXCHANGE, INFRARED SPECTROSCOPY AND NUCLEAR MAGNETIC RESONANCE  

Microsoft Academic Search

Thorium complexing by malic acid, trihydroxyglutaric acid, tartaric ; acid, alpha -hydroxyisobutyric acid and mandelic acid was followed by means of ; ion exchange at various concentrations of complexing agent and pH. The ; instability constants, and composition of the complexes are listed. The average ; effective charge on the complex was determined by ion exchange. Polynuclear ; thorium complexes

I. Geletseanu; A. V. Lapitskii

1962-01-01

278

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

SciTech Connect

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

NONE

1995-01-01

279

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

SciTech Connect

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

Not Available

1993-05-01

280

Effect of ion exchange of glazed dental glass ceramics on strength parameters.  

PubMed

Ion exchange treatments can significantly increase the strength of dental glass ceramic core materials by induced compressive residual stresses. However, the core materials of dental restorations need to be veneered or at least to be stained and glazed for esthetic and functional reasons. The objective of this study was to determine the effect of different ion exchange treatments on the strength parameters of stained and glazed glass ceramics. Batches of specimens made of a leucite reinforced dental glass with and without staining and glazing layer, untreated, single ion exchanged (KNO3), and dual ion exchanged (1. KNO3/27, 2. 30 mol% NaNO3/70 mol% KNO3) were tested. The strength of the core material was increased from 117 to 213 MPa by single ion exchange. Staining and glazing increased the strength up to 165 MPa. Single ion exchange of the stained and glazed core caused only a slight additional strength increase up to 173 MPa. The dual ion exchanged stained and glazed core exhibit a strength of 195 MPa and decreased the large strength scatter because of a well-designed residual stress profile. We conclude that dual ion exchange treatments could significantly increase the mechanical reliability of stained and glazed glass ceramic restorations. PMID:15573399

Fischer, H; Brehme, M; Telle, R; Marx, R

2005-02-01

281

Separation of 90Y from 90Sr using zirconium vanadate as the ion exchanger.  

PubMed

The sorption and desorption behaviour of several radionuclides, including 241Am, 152,154Eu, 233U, 137Cs, 90Sr and 90Y was studied under varying acidities using zirconium vanadate as ion exchanger. The sorption follows the order: Cs > Eu > Am >Y > U, while Sr was not taken up by the ion exchanger. A radiochemical separation scheme for the 90Y daughter from its 90Sr parent using zirconium vanadate ion exchanger has been developed. The exchanger was synthesized and characterized in our laboratory. PMID:15082037

Roy, K; Mohapatra, P K; Rawat, N; Pal, D K; Basu, S; Manchanda, V K

2004-05-01

282

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

283

Silver nanoclusters formation in ion-exchanged waveguides by annealing in hydrogen atmosphere  

Microsoft Academic Search

Light waveguides containing silver, introduced by ion-exchange process in soda-lime glass, has been annealed in hydrogen atmosphere at temperatures in the 120–250°C range. Annealings cause a near-surface precipitation of metallic silver to form nanometer-size clusters with good uniformity in size and spatial distribution. Hydrogen permeation and ion-exchange between hydrogen and sodium (which remains in the glass matrix after silver-for-sodium exchange)

G. De Marchi; F. Caccavale; F. Gonella; G. Mattei; P. Mazzoldi; G. Battaglin; A. Quaranta

1996-01-01

284

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

Microsoft Academic Search

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

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

2004-01-01

285

REMOVAL OF IRON FROM AQUEOUS SOLUTIONS BY ION EXCHANGE WITH NAY ZEOLITE  

Microsoft Academic Search

Iron removal from aqueous solutions by batch ion exchange with a solid Na-Y zeolite has been studied. The pH of the solution was monitored continuously during the ion exchange process and the impact of pH on iron hydroxide precipitation and zeolite structural stability is discussed. In the case of the Fe(II)\\/Na-Y exchange system, the pH of the iron solutions was

Jong Sung Kim; Ling Zhang; Mark A. Keane

2001-01-01

286

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

287

Revised Thermal Analysis of LANL Ion Exchange Column  

SciTech Connect

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

Laurinat, J

2006-04-11

288

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

289

Determination of SrSO 04 ion pair formation using conductimetric and ion exchange techniques  

NASA Astrophysics Data System (ADS)

The dissociation constant for SrSO 04 ion pair was determined at 25°C using conductance and ion-exchange techniques. Both approaches yield values for pK of SrSO 04 at zero ionic strength in the range 2.28-2.31. Previously reported values range from 2.1 to 3.0. The refinement in the dissociation constant should allow more reliable appraisals of the extent of strontium mineral solubility controls on strontium concentrations in natural water systems. The Lee and Wheaton conductance model was used to interpret the results of the conductivity measurements in strontium sulphate solutions at 25°C. Because of the limitations imposed by the solubility of celestite, a sufficiently-wide concentration range to enable determination of all three of the parameters - dissociation constant, ?0, and the distance parameter could not be made. Instead, values are reported for the dissociation constant and ?0 using reasonable limiting values for the distance parameter. Dowex-50 was used in the ion-exchange technique to determine the dissociation constant for SrSO 04. This method was used to determine values at other temperatures as well. Although there is considerable scatter in the temperature data, a standard enthalpy for the dissociation reaction: SrSO04? Sr2+ + SO2-4 is computed to be 8.7 ± 2 kJmole-1 at 25°C.

Reardon, E. J.

1983-11-01

290

Synthesis, structural characterization, and performance evaluation of resorcinol-formaldehyde (RF) ion-exchange resin  

Microsoft Academic Search

The 177 underground storage tanks at the DOE`s Hanford Site contain an estimated 180 million tons of high-level radioactive wastes. It is desirable to remove and concentrate the highly radioactive fraction of the tank wastes for vitrification. Resorcinol-formaldehyde (R-F) resin, an organic ion-exchange resin with high selectivity and capacity for the cesium ion, which is a candidate ion-exchange material for

T. L. Hubler; J. A. Franz; W. J. Shaw; S. A. Bryan; R. T. Hallen; G. N. Brown; L. A. Bray; J. C. Linehan

1995-01-01

291

Silver ion-exchanged sodium titanate and resulting effect on antibacterial efficacy  

Microsoft Academic Search

Surface modification with silver ion is an effective way to reduce infections. In the present work, the effect of silver ion-exchanged sodium titanate on the titanium has characterized by thin film X-ray diffraction analysis (TF-XRD) and high resolution scanning electron microscopy (HR-SEM). Antibacterial activity of silver ion-exchanged sodium titanate on titanium was assessed by the plate-counting method using against Staphylococcus

Sang-Bae Lee; Unursaikhan Otgonbayar; Ju-Hye Lee; Kwang-Mahn Kim; Kyoung-Nam Kim

2010-01-01

292

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

Microsoft Academic Search

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

A. Bilewicz; R. Dybczynski; J. Narbutt

1991-01-01

293

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

294

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

295

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

National Technical Information Service (NTIS)

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

J. H. Fitch

1981-01-01

296

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

297

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

NASA Astrophysics Data System (ADS)

We compare the ion exchange selectivity of phenol-type sorbents based on phenol formaldehyde resins, products of condensation of diatomic phenols with formaldehyde, and crosslinked polymer based on C-phenyl[4]resorcinarene resin, for cesium and rubidium ions. It is shown that phenol formaldehyde sorbents are the ones most selective. The interaction of alkali metal cations with the anion of calix[4]arene is investigated via quantum-chemical modeling. It is shown that the selectivity toward cesium and rubidium ions in ion exchangers of the phenolic type is not due to specific interactions of ions with phenolic groups.

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

2013-01-01

298

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

299

Ion Exchange Resin and Clay Vitrification by Plasma Discharges  

SciTech Connect

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

Diaz A, Laura V. [Instituto Nacional de Investigaciones Nucleares, km 36.5, Carretera Mexico-Toluca, Ocoyoacac, Edo. de Mexico (Mexico); Universidad Autonoma de Queretaro, CEACA, Ave. Hidalgo S/N, Cerro de las Campanas, Qro., Queretaro (Mexico); Pacheco S, Joel O.; Pacheco P, Marquidia; Monroy G, Fabiola; Emeterio H, Miguel; Ramos F, Fidel [Instituto Nacional de Investigaciones Nucleares, km 36.5, Carretera Mexico-Toluca, Ocoyoacac, Edo. de Mexico (Mexico)

2006-12-04

300

Ion Exchange Resin and Clay Vitrification by Plasma Discharges  

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

301

Design of zeolite ion-exchange columns for wastewater treatment  

SciTech Connect

Oak Ridge National Laboratory plans to use chabazite zeolites for decontamination of wastewater containing parts-per-billion levels of {sup 90}Sr and {sup 137}Cs. Treatability studies indicate that such zeolites can remove trace amounts of {sup 90}Sr and {sup 137}Cs from wastewater containing high concentrations of calcium and magnesium. These studies who that zeolite system efficiency is dependent on column design and operating conditions. Previous results with bench-scale, pilot-scale, and near-full-scale columns indicate that optimized design of full-scale columns could reduce the volume of spent solids generation by one-half. The data indicate that shortcut scale-up methods cannot be used to design columns to minimize secondary waste generation. Since the secondary waste generation rate is a primary influence on process cost effectiveness, a predictive mathematical model for column design is being developed. Equilibrium models and mass-transfer mechanisms are being experimentally determined for isothermal multicomponent ion exchange (Ca, Mg, Na, Cs, and Sr). Mathematical models of these data to determine the breakthrough curves for different column configurations and operating conditions will be used to optimize the final design of full-scale treatment plant. 32 refs., 6 figs., 3 tabs.

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

1991-01-01

302

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

303

Investigation of the resistance of some naturally occurring and synthetic inorganic ion exchangers against gamma radiation  

NASA Astrophysics Data System (ADS)

The effect of various doses of gamma radiation on the ion-exchange capacity, distribution coefficient values, elution behaviour, physical effect, pH titration and infrared spectra of some synthetic inorganic ion exchangers, namely the cerium substituted phosphates; and naturally occurring inorganic ion exchangers, zeolites from different parts of Iran, have been studied systematically. No significant change has been observed in the ion-exchange capacity (with the exception of CeP(Na), CeP(Di·Na) and zeolite 5 (deposits of arababad talas)), elution behaviour, physical effect, chemical stability and the infrared spectra of the synthetic ion exchangers irradiated upto a total dose of 200 kGy, while a change has been observed in the pH-titration and distribution behaviour. The increase in pH is sharper for irradiated samples with divalent cations than for the normal samples. Furthermore, the Kd values, and hence the selectivity towards certain cations increase with the total dose absorbed, reaching its optimum selectivity with the dose of 50-100 kGy. The natural zeolites chosen for these studies, show, similar pattern to those of synthetic ion exchangers, and in some cases an extremely high selectivity toward certain cations, like Be II. These make, zeolites, which are naturally occurring ion exchangers more viable economically, and extremely useful alternative in this industry.

Nilchi, A.; Khanchi, A.; Ghanadi Maragheh, M.; Bagheri, A.

2003-02-01

304

Shrinking core model for multispecies uptake onto an ion exchange resin involving distinct reaction fronts  

Microsoft Academic Search

A shrinking core model is derived for multispecies ion exchange when the counter-ions advance through the resin at different rates, leading to regions with distinctly different occupancies across the particle profile. The model generalizes an earlier version by accounting for the displacement between the various ions at the interfaces separating the regions. The model is applied to the uptake of

Mark Pritzker

2005-01-01

305

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

306

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

SciTech Connect

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

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

1992-06-01

307

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

SciTech Connect

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

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

1988-06-20

308

Composite ion exchanger with ammonium molybdophosphate and its properties  

Microsoft Academic Search

An organic binding polymer based on polyacrylonitrile (PAN) was used for the preparation of the composite exchanger containing ammonium molybdophosphate (AMP) as the active component. Due to the improvement of granulometric properties of powdered AMP with a binding polymer, an exchanger suitable for the application in column operations was prepared. Study of the properties of the exchanger AMP-PAN proved that

F. Šebesta; V. Štefula

1990-01-01

309

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

310

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

311

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

312

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

SciTech Connect

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

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

2008-04-01

313

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

NASA Astrophysics Data System (ADS)

Effects of silver ion-exchange on optical absorption (OA) and photoluminescence (PL) spectra of a cerium doped soda-lime-silicate glass at room temperature are investigated. The optical spectra are described in terms of the characteristic transitions 4f?5d originated in Ce 3+ ions placed mainly in two different sites of the glass network. As Ag + ions are introduced into the cerium doped glass, they are reduced to elementary silver (Ag 0) which are favoured by the reaction Ce 3++Ag +?Ce 4++Ag 0. Then, the number of Ce 3+ ions decrease inversely with depth from the surface contrarily to Ce 4+ ions does, and elementary silver diffuses and aggregates to form nanoparticles. As a consequence of these changes, the OA spectra of exchanged samples increase substantially in the UV range and the luminescence decreases significantly. The high sensitivity of PL together with deconvolution analysis of spectra, however, allows us to detect changes in the excitation and emission spectra from the earlier stages of ion-exchange. This indicates that during the ion-exchange we deal with fast processes (much shorter than 1 min). In fact, transmission electron microscopy observations of samples from the glass exchanged for a short time as 1 min at 325°C show the presence of a scanty number of silver nanoparticles, which confirms this point. Furthermore, with increasing the length of time of ion-exchange, PL spectra exhibit a progressive red shift indicative in part of a covalence increment in the oxygen-cerium coordinated bonding. We observe no luminescence from Ag + ions and other silver molecular species in contrast with other preliminary PL studies on silver ion-exchange in soda-lime-silicate glasses free of cerium. The effect is discussed on the basis of a supplementary increase in the number of Ce 4+ ions mainly due to the reaction Ce 3++Ag +?Ce 4++Ag 0, which prevents efficiently the luminescence of the silver centers.

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

2001-09-01

314

A U-shaped bilayer graphene channel transistor with a very high Ion\\/Ioff ratio  

Microsoft Academic Search

A novel graphene transistor architecture is reported. The transistor has a U-shape geometry and was fabricated using a gallium focused ion beam (FIB). The channel conductance was tuned with a back gate. The Ion\\/Ioff ratio exceeded 10^5.

Z. Moktadir; S. A. Boden; A. Ghiass; H. Rutt; H. Mizuta

2010-01-01

315

Ion temperature from tangential charge exchange neutral analysis on the Tokamak Fusion Test Reactor  

SciTech Connect

Fokker-Planck simulations of the Tokamak Fusion Test Reactor (TFTR) energetic ion mode discharges were performed to evaluate the utility of deriving the central ion temperature, T/sub i/, from deuterium neutral beam charge exchange spectra above the neutral beam injection energy. The T/sub i/ values obtained from fitting the calculated spectra obtained from sightlines nearly tangent to the neutral beam injection radius reproduce the central ion temperature within +-10% over the full range of TFTR energetic ion mode parameters. The code simulations demonstrate that the ion temperature obtained from the high energy tangential deuterium charge exchange spectrum is insensitive to variations in the plasma density, Z/sub eff/, plasma current, loop voltage, and injected neutral beam power and energy. Use of this method to reduce charge exchange data from TFTR energetic ion mode plasmas is demonstrated. 17 refs., 22 figs., 2 tabs.

Fiore, C.L.; Medley, S.S.; Hammett, G.W.; Kaita, R.; Roquemore, A.L.; Scott, S.D.

1987-09-01

316

Monomode low loss optical waveguide in KTiOPO4 formed by combining ion implantation with ion exchange  

NASA Astrophysics Data System (ADS)

Monomode KTiOPO4 waveguide was formed by ion implantation with 500 keV O+ ions at a dose of 1×1015 ions cm-2 and the following ion exchange in pure RbNO3 at 340 °C for 45 min. Results indicate that it is an effective method to modulate the waveguide modes by combining ion exchange with ion implantation. Positive changes in both nx and ny refractive indices occur in the waveguide region. Continuous and homogenous field pattern of the propagation light in the waveguide was collected and studied using the end-coupling method. The irradiation damage as well as the Rb distribution was analyzed by means of the Rutherford backscattering spectrometry technique. The concentration profiles of Rb and K in KTiOPO4 were measured by the time of flight secondary ion mass spectrometry. Results show that the lattice damages formed by ion implantation act as a diffusion barrier, which stop the Rb ion and K ion exchange in the deeper depth.

Wang, Liang-Ling; Wang, Ke-Ming; Lu, Fei; Shi, Bo-Rong; Wang, Xue-Lin; Wang, Lei; Lu, Qing-Ming

2008-09-01

317

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

Code of Federal Regulations, 2012 CFR

...capable of operating at a temperature in the range of 100 °C to 200 °C. (2) Ion exchange columns. Cylindrical columns...capable of operating at a temperature in the range of 100°C to 200°C and pressures above 0.7 MPa (102...

2012-01-01

318

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

Code of Federal Regulations, 2011 CFR

...capable of operating at a temperature in the range of 100 °C to 200 °C. (2) Ion exchange columns. Cylindrical columns...capable of operating at a temperature in the range of 100°C to 200°C and pressures above 0.7 MPa (102...

2011-01-01

319

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

...capable of operating at a temperature in the range of 100 °C to 200 °C. (2) Ion exchange columns. Cylindrical columns...capable of operating at a temperature in the range of 100 °C to 200 °C and pressures above 0.7 MPa (102...

2014-01-01

320

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

SciTech Connect

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

Spires, Renee; Punch, Timothy; McCabe, Daniel

2009-02-11

321

Influence of the ionic strength and solid\\/solution ratio on Ca(II)-for-Na + exchange on montmorillonite. Part 1: Chemical measurements, thermodynamic modeling and potential implications for trace elements geochemistry  

Microsoft Academic Search

Na\\/Ca ion-exchange isotherms were performed on a Na-saturated montmorillonite for different constant normalities of the aqueous chloride solution and at two solid\\/solution ratios. The experimental data suggest that the affinity of Na+ for the solid increases with total normality and m\\/V ratio and that a significant proportion of CaCl+ is also sorbed. A thermodynamic modeling procedure with one sorption site

E. Tertre; D. Prêt; E. Ferrage

2011-01-01

322

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

323

Preparation of ion exchanger layered electrodes for advanced membrane capacitive deionization (MCDI).  

PubMed

A noble electrode for capacitive deionization (CDI) was prepared by embedding ion exchanger onto the surface of a carbon electrode to practice membrane capacitive deionization (MCDI). Bromomethylated poly (2, 6-dimethyl-1, 4-phenylene oxide) (BPPO) was sprayed on carbon cloth followed by sulfonation and amination to form cation exchange and anion exchange layers, respectively. The ion exchange layers were examined by Scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FT-IR). The SEM image showed that the woven carbon cloth was well coated and connected with BPPO. The FT-IR spectrum revealed that sulfonic and amine functional groups were attached on the cationexchange and anionexchange electrodes, respectively. The advantages of the developed carbon electrodes have been successively demonstrated in a batch and a continuous mode CDI operations without ion exchange membranes for salt removal using 100 mg/L NaCl solution. PMID:21777933

Lee, Ju-Young; Seo, Seok-Jun; Yun, Sung-Hyun; Moon, Seung-Hyeon

2011-11-01

324

Grain-size distribution in ion-exchange resins  

Microsoft Academic Search

We have investigated the polydisperse composition of the carboxyl cation exchangers KB-4P-2, KB-2, and the sulfonic cation exchangers KU-20 and SDV-3T. Dry and wet sieving of the carboxyl and sulfonic cation exchangers was carried out on screens of various sizes for the experimental verification of the size distribution of the ionexchanger grains: 0.1, 0.2, 0.25, 0.355, 0.5, 0.63, i, 1.5,

L. M. Klyueva; N. I. Gel'perin

1975-01-01

325

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

326

Loading and Unloading Resin from MPPF Rapid Ion-Exchange Columns.  

National Technical Information Service (NTIS)

A process was developed which permits changing the resin in the Multipurpose Processing Facility Rapid Ion Exchange columns, without replacing the entire column assembly. The columns remain on the rack during the resin removal and replacement. The resin d...

W. C. Ng

1981-01-01

327

Radium Removal from Canadian Uranium Mining Effluents by a Radium-Selective Ion Exchange Complexer.  

National Technical Information Service (NTIS)

A laboratory test program was initiated by the Department of Energy, Mines and Resources as part of the National Uranium Tailings Program to investigate the applicability of a radium-selective ion exchange complexer for removing radium from Canadian urani...

1984-01-01

328

Leachability of Cesium from Cemented Evaporator Concentrates and Ion-Exchange Resins.  

National Technical Information Service (NTIS)

Leachabilities of cesium from cemented evaporator concentrates and ion-exchange resins were measured. The standard draft of the International Organization for Standardization (ISO, 1979) for long-term leach testing was followed in the research. Three resi...

A. Muurinen

1985-01-01

329

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

National Technical Information Service (NTIS)

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 Engineer...

J. L. Collins D. J. Davidson C. W. Chase B. Z. Egan D. D. Ensor

1993-01-01

330

Demonstration of Regenerable, Large-Scale Ion Exchange System Using WBA Resin in Rialto, CA.  

National Technical Information Service (NTIS)

The objective of this demonstration was to test and validate weak base ion exchange (WBA IX) technology using established performance objectives in order to obtain permitting and certification from the California Department of Public Health (CDPH) as an a...

A. M. Davis E. N. Coppola J. A. Rine

2012-01-01

331

Leachability of Decontamination Ion-Exchange Resins Solidified in Cement at Operating Nuclear Power Plants,  

National Technical Information Service (NTIS)

Data are presented on the release of radionuclides, stable metals, and organic reagents from decontamination ion-exchange resin wastes solidified in Portland cement. Both solidified and unsolidified decontamination resin waste samples were collected from ...

C. V. McIsaac J. W. Mandler

1989-01-01

332

Study of Mechanical and Physicochemical Properties of Cementated Spent Ion-Exchange-Resins.  

National Technical Information Service (NTIS)

As first part of a study on the possibilities, to immobilize spent ion exchange resins, for final disposal, the dependence of compressive strength from the composition of cement - resin mixtures was detected. Powdered resins, bead resins and ashes from th...

P. Patek

1981-01-01

333

Conditioning of spent ion exchange resins by embedding in compound matrices.  

National Technical Information Service (NTIS)

In ion exchange resin (IER) embedding by the epoxide process, the polymerization temperature peak can be a limit, due to the damages possibly occurring in the solidified IER form. Two evolutions of the epoxide process, using compound matrices, are present...

C. J. Kertesz

1991-01-01

334

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

335

Evaluation of a Precipitation-Ion Exchange Process for Treatment of Laundry Waste.  

National Technical Information Service (NTIS)

Bench-scale pilot plant studies were conducted to evaluate chemical coagulation and ion exchange for decontamination of 2724-W laundry wastewater. Chemical coagulation is accomplished at pH 11 to avoid complexant problems and assure good transuranic radio...

B. W. Mercer L. L. Ames

1977-01-01

336

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

SciTech Connect

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

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

2009-03-17

337

Quantum ion-acoustic solitary waves: The effect of exchange correlation  

NASA Astrophysics Data System (ADS)

Quantum ion-acoustic solitary waves are studied by considering the effects of exchange and correlation for the electrons. Starting from one-dimensional quantum hydrodynamic equations, including the term of exchange correlation for electrons, we obtain a model in which two dimensionless parameters appear (in addition to the parameter measuring the quantum diffraction) measuring the exchange and the correlation. A new deformed Korteweg-de Vries equation is derived. The effect of exchange and correlation is reflected in the phase speed as well as in the nonlinear and dispersion terms. Its solution shows that the exchange-correlation effects modify the amplitude as well as the width of the weak solitary waves. In the arbitrary amplitude regime, and as may be expected, a pseudopotential analysis shows that the exchange-correlation effects may change the nature (compressive or rarefactive) of the quantum ion-acoustic solitary waves. Our results complement and give new insight into the previously published work on this problem.

Ourabah, Kamel; Tribeche, Mouloud

2013-10-01

338

Irradiation-induced Ag-colloid formation in ion-exchanged soda-lime glass  

Microsoft Academic Search

Ion-exchanged glass samples were obtained by immersing soda-lime slides in molten salt baths of molar concentration in the range 1–20% AgNO3 in NaNO3, at temperatures varying from 320 to 350°C, and processing times of the order of a few minutes. Irradiations of exchanged samples were subsequently performed by using H+m, He+, N+ ions at different energies in order to obtain

F. Caccavale; G. De Marchi; F. Gonella; P. Mazzoldi; C. Meneghini; A. Quaranta; G. W. Arnold; G. Battaglin; G. Mattei

1995-01-01

339

Stability of phenol-formaldehyde ion-exchange sorbents in aqueous solutions  

Microsoft Academic Search

It is shown that ion-exchange sorbents based on phenol-formaldehyde resins can be used for a long time for isolating and separating rare alkali metals without any significant changes in the ion-exchange selectivity and capacity. When the phenol sorbents were used in alkaline solutions at elevated temperatures, carboxyl groups gradually accumulated in them as a result of the oxidation of methylol

L. A. Shelkovnikova; O. T. Gavlina; V. A. Ivanov

2011-01-01

340

Stability of phenol-formaldehyde ion-exchange sorbents in aqueous solutions  

Microsoft Academic Search

It is shown that ion-exchange sorbents based on phenol-formaldehyde resins can be used for a long time for isolating and separating\\u000a rare alkali metals without any significant changes in the ion-exchange selectivity and capacity. When the phenol sorbents\\u000a were used in alkaline solutions at elevated temperatures, carboxyl groups gradually accumulated in them as a result of the\\u000a oxidation of methylol

L. A. Shelkovnikova; O. T. Gavlina; V. A. Ivanov

2011-01-01

341

Prominent redox feature of copper ion exchanged in ZSM-5-type zeolite  

Microsoft Academic Search

The redox features of copper ion exchanged in ZSM-5 were investigated in both evacuation–oxidation–re-evacuation and evacuation–hydration–re-evacuation processes. The XANES and ESR spectra clearly indicated the conversion of Cu(II) ion exchanged in ZSM-5 into Cu(I) with increasing evacuation temperatures. The ability of Cu(I) formed to undergo a complete oxidation with O2 at 673K was certified and succeeding reduction process by heat

Yasushige Kuroda; Ryotaro Kumashiro; Mahiko Nagao

2002-01-01

342

Control of micropore formation in the carbonized ion exchange resin by utilizing pillar effect  

Microsoft Academic Search

A new method is presented for controlling the micropore structure of porous carbon by use of pillar effect of metal and\\/or sulfur compounds. An ion exchange resin having sulfonic acid groups as ion exchangeable functional groups was used as a raw material. Resins having various cations of H+, K+, Na+, Ca2+, Zn2+, Cu2+, Fe2+, Ni2+ and Fe3+ were prepared from

H Nakagawa; K Watanabe; Y Harada; K Miura

1999-01-01

343

Behavior of carboxyl-bound potassium during combustion of an ion-exchanged lignite  

Microsoft Academic Search

The reactions of potassium during combustion of a potassium-ion-exchanged Beulah lignite have been investigated. Combustion was carried out in a drop-tube furnace and CCSEM and XAFS spectroscopy were used to characterize the coal and ash samples. The reactions of the ion-exchanged potassium were quite similar to those of carboxyl-bound sodium in the original coal. The principal K-containing ash phases observed

Anup D. Shah; Gerald P. Huffman; Frank E. Huggins; Naresh Shah; Joseph J. Helble

1995-01-01

344

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

345

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 250 citations and includes a subject term index and title list.)

Not Available

1993-12-01

346

Simulation of the Effects of Charge Exchange in Penning Ion Sources  

Microsoft Academic Search

Summary form only given. We investigate numerically the effects of charge exchange in a Penning ion source for neutron generators. We use particle-in-cell modeling with Monte Carlo collision to simulate the electron and ion dynamics, including charge exchange, for parameters typical of DC sources in use today (device size of a few cm, bias voltage of 2 kV, extraction voltage

P. Stoltz; P. Messmer; D. L. Chichester

2007-01-01

347

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

348

Dual-temperature reagent-less ion-exchange separations of alkali metal salts on zeolites  

Microsoft Academic Search

Ion exchange equilibria in the mixed K2SO4–Na2SO4 and CsCl–NaCl solutions with concentrations within the range of 2.2–2.9 equiv\\/l on the natural clinoptilolites have been studied. The equilibrium coefficients for the Na+–K+ and Na+–Cs+ exchanges on clinoptilolite decreased significantly with temperature when the equivalent fractions of K+ and Cs+ ions in the zeolite phase were very low. Accordingly, the differential enthalpy

V. A Ivanov; V. D Timofeevskaja; O. T Gavlina; V. I Gorshkov

2003-01-01

349

Determination of arsenic, tungsten, and antimony in natural waters by neutron activation and inorganic ion exchange  

Microsoft Academic Search

Ion exchange on AlâOâ columns has been used to quantitatively measure As, Sb, and W in water. This procedure requires short thermal neutron irradiations; rapid ion exchange without chemical manipulations, and short ..gamma..-ray counts on a Ge(Li) detector. Precisions of +-5% can be routinely obtained and the following detection limits have been achieved: As, 0.05 ppb; Sb, 0.03 ppb; and

Ernest S. Gladney; James W. Owens

1976-01-01

350

THERMAL PERFORMANCE ANALYSIS FOR SMALL ION-EXCHANGE CESIUM REMOVAL PROCESS  

Microsoft Academic Search

The In-Riser Ion Exchange program focuses on the development of in-tank systems to decontaminate high level waste (HLW) salt solutions at the Savannah River Site (SRS) and the Hanford Site. Small Column Ion Exchange (SCIX) treatment for cesium removal is a primary in-riser technology for decontamination prior to final waste immobilization in Saltstone. Through this process, radioactive cesium from the

S. Lee; W. King

2009-01-01

351

Ion-exchange in fluidized\\/expanded beds for recovery of L-phenylalanine  

Microsoft Academic Search

Experimental and theoretical studies were carried out to investigate the performance of a batch, fluidized\\/expanded bed ion-exchange system. Exchange of scL-phenylalanine on cation exchange resin was studied in columns of 1-4 cm diameter and in the linear velocity range 5-40 cm\\/min. The breakthrough curves were obtained at various design and operating conditions with changing column size, distributor, feed pH, bed

Joon-Ho Koh

1995-01-01

352

Use of ion-exchange resins in the manufacture of pharmaceutical chemical preparations  

Microsoft Academic Search

Sulfaguanidine is ionized in aqueous media by adding a proton (pK a 2.3 + 0.04). Consequently its absorption by ion exchange is possible from aqueous solutions onto strong acid cation exchangers. Experiments have been carried out under dynamic conditions. We used the interaction of sulfaguanidine solutions with the sulfonic cation exchanger KU-2. The equilibrium state was determined from an expression

G. N. Al'tshuler; E. A. Savel'ev; N. A. Shubovich

1970-01-01

353

Gas phase hydrogen\\/deuterium exchange of proteins in an ion trap mass spectrometer  

Microsoft Academic Search

Electrospray ionization ion trap mass spectrometry (ESI-ITMS) coupled with gas phase hydrogen\\/deuterium (H\\/D) exchange is demonstrated to be a useful tool to investigate the gas phase conformations of proteins when coupled with a mechanistic understanding of exchange. We have investigated the H\\/D exchange of multiple charge states of lysozyme, cytochrome c, ubiquitin, insulin, thioredoxin and melittin with deuterated methanol in

Sarah E. Evans; Nathan Lueck; Elaine M. Marzluff

2003-01-01

354

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

Microsoft Academic Search

Variable effects were noted on the argon (Ar) and potassium (K) contents of clinoptilolite fractions used in ion-exchange and dehydration experiments. The K contents of clinoptilolite fractions were differently affected during cation exchange with Ca-, Cs-, K-, and Na-chloride solutions. Ar was generally less affected during these experiments, except for a Na-clinoptitolite fraction exchanged for five days. Loss of Ar

WoldeGabriel

1995-01-01

355

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

356

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

SciTech Connect

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

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

2013-05-15

357

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

NASA Astrophysics Data System (ADS)

Ion exchange resins are widely used for separating ions in the solution, desalination, removal of impurities, and etc. Giving a new function to these ion exchange resins enables the application in more various fields. Until now, we carried out the research work about the following 5 project.: (1) Conversion of ion exchange resins into selective adsorbents by using low molecular reagents, which possess capabilities of a selective reaction with target ions, ion exchange reaction with the ion exchange resin and strong physical adsorption to the ion exchange resin. (2) Synthesis of resins for ion exchange high performance liquid chromatography (IEHPLC) and the analysis of biomaterials. (3) Development of insoluble macromolecular Sn(II) complex based on the aminophosphonic acid type ion exchange resin and its application to the 99mTc labeling of proteins. (4) Development of a new 68Ge-68Ga generator using N-methylglucamine type organic polymer as the adsorbent for 68Ge and production of 68Ga for PET. (5) Preparation of an ion-exchangeable polymer bead wrapped with bilayer membrane structures. In this paper, the application of various functional resins prepared based on ion exchange resin in the field of pharmaceutical sciences has been summarized.

Nakayama, Morio

358

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

359

Sorption kinetics of ammonia and ammonium ions on gel and macroporous sulphonic acid cation exchangers  

Microsoft Academic Search

Diffusion of ammonia and ammonium ions in sulphonic acid cation exchangers (gel Purolite SGC 100×10 MBH and macroporous Purolite C 160 MBH) from the solutions, representing the composition of “caustic condensate” (waste of nitrogen fertilizers production) is affected by pH of initial solution and structure of the matrix of cation exchanger. In gel matrix the effective intraparticle diffusivity (Def) depends

D. Kaušp?dien?; J. Snukiškis

2006-01-01

360

Arsenic removal from drinking water through a hybrid ion exchange membrane – Coagulation process  

Microsoft Academic Search

A hybrid process targeting arsenic (As) removal from drinking water was developed in this study, consisting of arsenate transport through an anion exchange membrane followed by coagulation. The main advantage of this ion exchange membrane (IEM) process is improved drinking water quality through the prevention of secondary contamination by coagulants and pH-controlling agents, a design feature that was successfully confirmed

Adrian Oehmen; Rita Valerio; Javier Llanos; Joana Fradinho; Susana Serra; Maria A. M. Reis; Joao G. Crespo; Svetlozar Velizarov

2011-01-01

361

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

National Technical Information Service (NTIS)

Assessing the suitability of Yucca Mtn., NV as a potential repository for high-level nuclear waste requires the means to simulate ion-exchange behavior of zeolites. Vanselow and Gapon convention cation-exchange models have been added to geochemical modeli...

B. E. Viani C. J. Bruton

1992-01-01

362

Removal of ammonium from aqueous solution by ion exchange on natural and modified chabazite  

Microsoft Academic Search

The ammonium exchange capacity of a natural chabazite was studied in this work. The XRD analysis of the zeolite sample revealed that the main zeolitic phase was chabazite. The textural properties were determined by the N2-BET method and the surface morphology and charge were examined using a scanning electron microscope and a zetameter, respectively. The ion exchange equilibrium data were

R. Leyva-Ramos; J. E. Monsivais-Rocha; A. Aragon-Piña; M. S. Berber-Mendoza; R. M. Guerrero-Coronado; P. Alonso-Davila; J. Mendoza-Barron

2010-01-01

363

Application of a Novel Hybrid Cation Exchange Material in Metal Ion Separations  

Microsoft Academic Search

A novel hybrid cation exchange material of the class of tetravalent metal acid (TMA) salt, titanium diethylene triamine pentamethylene phosphonate (TiDETPMP) has been synthesized by the sol gel method. The material has been analyzed by spectroscopy and thermal methods. Physico-chemical and ion exchange characteristics have also been studied. The distribution coefficient (Kd) has been determined in aqueous as well as

Parimal Patel; Uma Chudasama

2011-01-01

364

Comparison between different ion exchange resins for the deacidification of passion fruit juice  

Microsoft Academic Search

Passion fruit is highly appreciated for its aroma, but its strong acidity limits its use in formulated food products. In this study, deacidification of clarified passion fruit juice using ion exchange resins has been evaluated. Ten commercial weakly basic anion exchange resins were compared using a 50 ml column. The deacidification was carried out in order to increase juice pH

Edwin Vera; Manuel Dornier; Jenny Ruales; Fabrice Vaillant; Max Reynes

2003-01-01

365

Separation of Cs137, Sr90, and Th-232 in Aqueous Solution by Using a Multistage Countercurrent Batch Contactor Ion-Exchange System  

Microsoft Academic Search

The radioisotopes Cs-137, Sr-90, and Th-232, in simulated high level nuclear liquid waste, were recovered and sequentially separated by using an 8-stage flask simulation of a multistage countercurrent batch contactor (MCBC) ion-exchange system. The solution normality ratio used for the three ions Cs:Sr:Th was 1:1:1. The solution was contacted for 2 h with resin Dowex HCR-W2 initially in the H

Chong Mook Park; Walter Meyer

1992-01-01

366

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

367

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

368

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

SciTech Connect

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

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

1991-01-01

369

Radium-thorium disequilibrium and zeolite-water ion exchange in a Yellowstone hydrothermal environment  

NASA Astrophysics Data System (ADS)

Whole rock samples of hydrothermally altered Biscuit Basin rhyolite from Yellowstone drill cores Y-7 and Y-8 were analyzed for 226Ra and 230Th to determine the extent of radioactive disequilibrium and its relation to the rates and mechanisms of element transport in the shallow portion of an active hydrothermal system. The ( 226Ra/230Th) activity ratios range from 0.73 to 1.46 and are generally correlated with Th-normalized Ba concentrations (Ba N). Values of ( 226Ra/230Th) and Ba N > 1 were found in samples containing large modal fractions of clinoptilolite; whereas values of ( 226Ra/230Th) and Ba N < 1 were found in samples containing large modal fractions of mordenite. Composition clinoptilolite and mordenite in these samples are consistent with ion exchange equilibrium between zeolites and coexisting thermal waters. Average K d mineral-waterBa values are 1.0·10 5 mL/g for clinoptilolite and 1.4·10 4 mL/g for mordenite. Apparent diffustvities through matrix porosity estimated for Ra and Ba range from ˜10 -12 to ˜10 -10 cm 2s -1 in thoroughly zeolitic rhyolite; these rates of diffusion are too low to account for the observed distance scale of ( 226Ra/230Th) disequilibrium. The correlated values of ( 226Ra /230Th) disequilibrium and Ba N represent zeolite-water ion exchange equilibrium that is caused by porous flow of water through the rock matrix and by the relatively rapid diffusion of cations within the zeolite lattices. A water flux of at least ˜2.5 ( cm water3/cm rock3) yr -1 is required to produce measurable ( 226Ra/230Th) disequilibrium, whereas at least ˜23 ( cm water3/cm rock3) yr -1 is r for the sample exhibiting the most extreme ( 226Ra/230Th) disequilibrium; these fluxes are much higher than those that can be inferred from net mass transfers of stable species. The zeolite-water ion exchange process appears to have been operating for at least 8000 yr in the environment of the Y-7 and Y-8 drill holes.

Sturchio, N. C.; Bohlke, J. K.; Binz, C. M.

1989-05-01

370

Formation of nonlinear optical waveguides by using ion-exchange and implantation techniques  

Microsoft Academic Search

Composite materials consisting of metal nanoclusters embedded in glass matrices have been obtained by the combined use of ion-exchange and ion implantation processes, with possible application in the design of nonlinear all-optical switching devices. Optical waveguides containing either silver or copper clusters have been fabricated. Optical absorption and electron microscopy have been performed to detect the presence of metal clusters.

G. W. Arnold; G. De Marchi; F. Gonella; P. Mazzoldi; A. Quaranta; G. Battaglin; M. Catalano; F. Garrido; R. F. Haglund

1996-01-01

371

Modeling ion exchange in glass with concentration-dependent diffusion coefficients and mobilities  

Microsoft Academic Search

Multimode buried waveguides made in silicate glass by field-assisted ion exchange present very asymmetric profiles. We show how this phenomenon originates in the large dependence of the kinetics on the local ion concentrations. For this purpose, we derive an interdiffusion equation that includes the effects of concentration-dependent diffusion coefficients and mobilities. We show how to deduce this dependence from measurements

Alexandru I. Lupascu; Antoine P. Kevorkian; Thierry Boudet; Francoise Saint-Andre; Dominique Persegol; Michel Levy

1996-01-01

372

Electrodialysis versus ion exchange: comparison of the cumulative energy demand by means of two applications  

Microsoft Academic Search

The aim of the present paper is the comparison of electrodialysis (ED) and ion exchange (IE) with regard to their cumulative energy demand by means of two applications separating ions with significantly different molar weight. Data for the separation of sodium gluconate and for the desalination of whey are obtained from laboratory experiments. Therefrom, a scale-up is done to an

Michael Greiter; Senad Novalin; Martin Wendland; Klaus-Dieter Kulbe; Johann Fischer

2004-01-01

373

Simulation of ion exchange water softening pretreatment for reverse osmosis desalination of brackish water  

Microsoft Academic Search

Prevention of membrane scaling in reverse osmosis (RO) desalination may require operation at low recoveries, which increases the amount of brine, increasing brine disposal costs and creating environmental hazard. Ion exchange (IEX) pretreatment removes Ca2+ and Mg2+ ions to limit scaling of salts. Use of concentrated water from RO process for regeneration of the IEX column eliminates the need for

Anand Venkatesan; Phillip C. Wankat

2011-01-01

374

FAST/TEAMS observations of charge exchange signatures in ions mirroring at low altitudes  

NASA Astrophysics Data System (ADS)

Using the TEAMS instrument on FAST, we have observed a case in which signatures of the inner edge of the plasma sheet are clearly observed in the energy spectra of ions mirroring at the FAST altitude. That inner edge is dominated by He+. We show that this is the natural composition expected from charge exchange as the ions drift in from the plasma sheet.

Kistler, L. M.; Möbius, E.; Klumpar, D. M.; Popecki, M. A.; Tang, L.; Jordanova, V.; Klecker, B.; Peterson, W. K.; Shelley, E. G.; Hovestadt, D.; Temerin, M.; Ergun, R. E.; McFadden, J. P.; Carlson, C. W.; Mozer, F. S.; Elphic, R. C.; Strangeway, R. J.; Cattell, C. A.; Pfaff, R. F.

375

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

Microsoft Academic Search

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

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

2011-01-01

376

Ion Exchange Reactions in Soils and Plants: Three Year Summary Report.  

National Technical Information Service (NTIS)

This report covers activities during three years, including studies of ion exchange reactions of Cs with soil and clay materials and studies concerned with the effects of acid soil conditions on accumulation of ions by plants. During this period we commen...

W. A. Jackson D. L. Craig

1965-01-01

377

Combined ion exchange treatment for removal of dissolved organic matter and hardness.  

PubMed

Dissolved organic matter (DOM) and hardness cations are two common constituents of natural waters that substantially impact water treatment processes. Anion exchange treatment, and in particular magnetic ion exchange (MIEX), has been shown to effectively remove DOM from natural waters. An important advantage of the MIEX process is that it is used as a slurry in a completely mixed flow reactor at the beginning of the treatment train. Hardness ions can be removed with cation exchange resins, although typically using a fixed bed reactor at the end of a treatment train. In this research, the feasibility of combining anion and cation exchange treatment in a single completely mixed reactor for treatment of raw water was investigated. The sequence of anion and cation exchange treatment, the number of regeneration cycles, and the chemistry of the regeneration solution were systematically explored. Simultaneous removal of DOM (70% as dissolved organic carbon) and hardness (>55% as total hardness) was achieved by combined ion exchange treatment. Combined ion exchange is expected to be useful as a pre-treatment for membrane systems because both DOM and divalent cations are major foulants of membranes. PMID:20117818

Apell, Jennifer N; Boyer, Treavor H

2010-04-01

378

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

379

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

380

A Method of Demineralization using Strongly Basic Ion Exchange Resins.  

National Technical Information Service (NTIS)

A new approach to demineralization of marginally brackish waters for individual domestic use has been proposed. An engineering evaluation of the use of various cation exchange resins is given. Primarily the report presents the test results for various com...

W. S. Midkiff

1972-01-01

381

INVESTIGATIONS OF ION EXCHANGE METHODS FOR RECOVERY OF URANIUM FROM LIQUORS PRODUCED BY ACID LEACHING OF GUNNAR ORE. Topical Report  

Microsoft Academic Search

An ion exchange testing program was completed on Gunnar acid leach ; liquors and pulps. A standard column system and a resin-in-pulp system, both ; using anion exchange resins, were investigated. The Gunnar leach liquors are ; readily amenable to the recovery of uranium by ion exchange. (auth);

N. N. Schiff; G. W. Lower

1954-01-01

382

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

383

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

PubMed

For the calibration purpose of thoron ((220)Rn) measurements, solid sources with constant (220)Rn emanation are generally desired. In this study, Th(4+) in the thorium nitrate powder was successfully exchanged to the surfaces of sodium benzenesulphonate resins with a bead diameter of ?0.5 mm by using the ion-exchange method. Tests of (220)Rn emanating from the ion-exchanged resin indicated that the emanation rates were nearly constant, provided both the air humidity and air temperature were controlled. As the resin can be easily prepared to be of various sizes and activities of sources, the ion-exchanged resin is considered as a promising standard source for calibrations of (220)Rn measurements. PMID:22908351

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

2012-11-01

384

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

SciTech Connect

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

Hurst, F.J.

1981-01-01

385

Formation of silver nanoparticles on the silicate glass surface after ion exchange  

NASA Astrophysics Data System (ADS)

It has been experimentally shown that water vapor thermal treatment of silicate glasses with silver ions introduced by ion exchange leads to the formation of a silver nanoparticle layer with a high packing density on the glass surface. The results of studying the morphology of samples by atomic force and electron microscopy and X-ray spectral analysis of the composition of nanoparticles, as well as the optical density and luminescence spectra in different stages of the treatment, are presented. Mechanisms explaining the processes responsible for silver nanoparticle formation upon water vapor thermal treatment on the glass surface after ion exchange are proposed.

Obraztsov, P. A.; Nashchekin, A. V.; Nikonorov, N. V.; Sidorov, A. I.; Panfilova, A. V.; Brunkov, P. N.

2013-06-01

386

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

387

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

PubMed

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

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

2006-02-28

388

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

389

Stability of phenol-formaldehyde ion-exchange sorbents in aqueous solutions  

NASA Astrophysics Data System (ADS)

It is shown that ion-exchange sorbents based on phenol-formaldehyde resins can be used for a long time for isolating and separating rare alkali metals without any significant changes in the ion-exchange selectivity and capacity. When the phenol sorbents were used in alkaline solutions at elevated temperatures, carboxyl groups gradually accumulated in them as a result of the oxidation of methylol groups with oxygen dissolved in the solution. This led to a considerable increase in the ion-exchange capacity of the sorbents and a simultaneous decrease in the selectivity with respect to Cs+-Rb+ and Rb+-K+ ions (it is desirable to avoid the drying of phenol ionites in air by storing them in a swelled state in closed vessels).

Shelkovnikova, L. A.; Gavlina, O. T.; Ivanov, V. A.

2011-09-01

390

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

391

Low-cost integrated optical waveguide polarizer with an hybrid structure of birefringent polymer and ion-exchanged glass waveguide  

NASA Astrophysics Data System (ADS)

We report on a new type of glass ion-exchanged waveguide TE polarizer using an electro-optic polymer (conjugated PMMA-DR1) overlay. The polarization function is assured by poling the polymer in the vertical direction using a Corona process. An extinction ratio of 39 dB is obtained at the wavelength of (lambda) equals 1.3 micrometer. The insertion losses of the device are in order of 7 dB. The performance of the polarizer are investigated. Our experimental investigations show a polarization efficiency over than 40 dB.

Sanchez Perez, Celia; Morand, Alain; Benech, Pierre; Tedjini, Smail; Bosc, Dominique; Rousseau, Alain

1999-03-01

392

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

PubMed

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

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

2014-01-01

393

Irradiation effects on the storage and disposal of radwaste containing organic ion-exchange media. [3 functional forms of resin - sulfonic acid cation exchanger, quarternary ammonium anion exchanger and mixed bed combination of the two  

Microsoft Academic Search

Polystyrene-divinylbenzene (PS-DVB) based ion exchangers are commonly used in water demineralization or decontamination operations at nuclear facilities. Self-irradiation from sorbed radionuclides may affect the properties of radwaste containing these ion-exchange media. The effects of external irradiation on anion, cation, and mixed bed PS-DVB ion exchangers have been investigated under conditions relevant to radwaste storage and disposal. Three effects are emphasized

K. J. Swyler; C. J. Dodge; R. Dayal

1983-01-01

394

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

395

Silver nanocluster formation in ion-exchanged glasses by annealing, ion beam and laser beam irradiation: An EXAFS study  

Microsoft Academic Search

Extended X-ray absorption fine structure analysis is used to determine the silver local environment in silicate glasses doped by the Ag-alkali ion-exchange process, followed by different treatments, namely, ion irradiation, thermal annealing in reducing atmosphere, laser irradiation. The obtained results indicate that metal nanocluster composites with different cluster structures may be formed with these multistep methodologies, pointing out the role

G. Battaglin; E. Cattaruzza; F. Gonella; R. Polloni; F. D’Acapito; S. Colonna; G. Mattei; C. Maurizio; P. Mazzoldi; S. Padovani; C. Sada; A. Quaranta; A. Longo

2003-01-01

396

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

PubMed

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

Mrozek, Piotr

2011-08-01

397

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

NASA Astrophysics Data System (ADS)

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

Mrozek, Piotr

2011-08-01

398

Radial stratification of ions as a function of mass to charge ratio in collisional cooling radio frequency multipoles used as ion guides or ion traps.  

PubMed

Collisional cooling in radio frequency (RF) ion guides has been used in mass spectrometry as an intermediate step during the transport of ions from high pressure regions of an ion source into high vacuum regions of a mass analyzer. Such collisional cooling devices are also increasingly used as 'linear', two-dimensional (2D) ion traps for ion storage and accumulation to achieve improved sensitivity and dynamic range. We have used the effective potential approach to study m/z dependent distribution of ions in the devices. Relationships obtained for the ideal 2D multipole demonstrate that after cooling the ion cloud forms concentric cylindrical layers, each of them composed of ions having the same m/z ratio; the higher the m/z, the larger is the radial position occupied by the ions. This behavior results from the fact that the effective RF focusing is stronger for ions of lower m/z, pushing these ions closer to the axis. Radial boundaries of the layers are more distinct for multiply charged ions, compared to singly charged ions having the same m/z and charge density. In the case of sufficiently high ion density and low ion kinetic energy, we show that each m/z layer is separated from its nearest neighbor by a radial gap of low ion density. The radial gaps of low ion population between the layers are formed due to the space charge repulsion. Conditions for establishing the m/z stratified structure include sufficiently high charge density and adequate collisional relaxation. These conditions are likely to occur in collisional RF multipoles operated as ion guides or 2D ion traps for external ion accumulation. When linear ion density increases, the maximum ion cloud radius also increases, and outer layers of high m/z ions approach the multipole rods and may be ejected. This 'overfilling' of the multipole capacity results in a strong discrimination against high m/z ions. A relationship is reported for the maximum linear ion density of a multipole that is not overfilled. PMID:11013419

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

2000-01-01

399

The chemical precipitation of nickel on ion exchangers and active carbons  

NASA Astrophysics Data System (ADS)

The chemical precipitation of nickel in the form of poorly soluble precipitates in ion exchanger matrices and on active carbons from solutions of nickel chloride and chemical nickel plating electrolytes was studied. The sorption of nickel ions from a solution of nickel chloride occurs most effectively on Purolite D24002 macroporous chelate forming ion exchanger, KU-23-15/100 sulfo cation exchanger, and KU-2-8 gel sulfo cation exchanger. Nickel enters sulfo cation exchangers in the form of counterions, and is adsorbed on Purolite D24002 largely because of complex formation. The subsequent precipitation of nickel in the solid state in matrix pores liberates ionogenic centers, which allows repeated sorption cycles to be performed. After three chemical precipitation cycles under static conditions, the amount of nickel is higher by 170-250% than the ion exchange capacity of the sorbents. The electrolyte of chemical nickel plating contains nickel predominantly in the form of negatively charged and neutral complexes with glycine, which cannot form bonds with the matrices under study. It is therefore reasonable to perform sorption at decreased solution pH values.

Khorol'Skaya, S. V.; Zolotukhina, E. V.; Polyanskii, L. N.; Peshkov, S. V.; Kravchenko, T. A.; Krysanov, V. A.

2010-12-01

400

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

PubMed

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

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

2014-03-01

401

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

NASA Astrophysics Data System (ADS)

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

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

2005-05-01

402

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

403

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

SciTech Connect

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

Benson, L.V.

1980-05-01

404

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...

405

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...

406

Ion Exchange Separation of Low Boric Acid Concentrations from Water.  

National Technical Information Service (NTIS)

Boric acid poisoning of the moderator of the TR-O experimental heavy water reactor was studied. The possibility is discussed of removing boric acid from heavy water by means of a strong basic anion exchanger, below the residual concentration of 0.01 mg B/...

J. Kysela J. Brabec F. Peterka

1975-01-01

407

BARIUM AND RADIUM REMOVAL FROM GROUNDWATER BY ION EXCHANGE  

EPA Science Inventory

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

408

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

409

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

410

Structure simulation into a lamellar supramolecular network and calculation of the metal ions/ligands ratio  

PubMed Central

Background Research interest in phosphonates metal organic frameworks (MOF) has increased extremely in the last two decades, because of theirs fascinating and complex topology and structural flexibility. In this paper we present a mathematical model for ligand/metal ion ratio of an octahedral (Oh) network of cobalt vinylphosphonate (Co(vP)·H2O). Results A recurrent relationship of the ratio between the number of ligands and the number of metal ions in a lamellar octahedral (Oh) network Co(vP)·H2O, has been deducted by building the 3D network step by step using HyperChem 7.52 package. The mathematical relationship has been validated using X ray analysis, experimental thermogravimetric and elemental analysis data. Conclusions Based on deducted recurrence relationship, we can conclude prior to perform X ray analysis, that in the case of a thermogravimetric analysis pointing a ratio between the number of metal ions and ligands number around 1, the 3D network will have a central metal ion that corresponds to a single ligand. This relation is valid for every type of supramolecular network with divalent metal central ion Oh coordinated and bring valuable information with low effort and cost.

2012-01-01

411

Temperature and Carbonate Ion Effects on Elemental Ratios in Benthic Foraminifera  

NASA Astrophysics Data System (ADS)

We have assessed temperature and carbonate ion effects on elemental ratios in benthic foraminifera using core top samples from Atlantic (Cape Hatteras Continental Shelf (CHCS) and Norwegian Sea) and Pacific (Indonesia, Hawaii, and New Zealand) depth transects. Our previous studies, based on comparing samples from Little Bahama Banks (LBB), Hawaii, and Indonesia (e.g., Rosenthal et al., 2005, 2006) have shown a significant difference in Mg/Ca ratios of calcitic species (Cibicidoides) and Mg/Ca and Sr/Ca of aragonitic species (Hoeglundina elegans) between sites characterized by the same temperature but different carbonate ion content, thereby suggesting that both variables influence the Mg/Ca and Sr/Ca composition of the foraminifera. It appears, however, that the major difference in these elemental ratios is between the LBB site and all other sites, rather than between the Atlantic and Pacific. The new results from the Atlantic suggest that foraminifera from the LBB transect may be compromised by diagenetic processes, and the carbonate ion effect is substantially smaller than previously thought. This conclusion, based on inter-basinal comparison, is consistent with our data from the homothermal, homosaline Norwegian Sea depth transect, which suggest minimal carbonate ion effect on Mg/Ca in calcitic benthic foraminifera. These data allow us to refine the Mg/Ca-temperature calibration for benthic species and assess temperature and carbonate ion effects on other trace elements (e.g., Li/Ca, B/Ca) under variable oceanographic conditions.

Jordan, K. A.; Rosenthal, Y.; Lear, C. H.; Keigwin, L.; Sikes, E. L.

2006-12-01

412

Development and evaluation of sustained release tablet of betahistine hydrochloride using ion exchange resin tulsion t344.  

PubMed

An attempt was made to sustain the release of Betahistine hydrochloride by complexation technique using strong cation-exchange resin, Tulsion T344. The drug loading onto ion-exchange resin was optimized for mixing time, activation, effect of pH, swelling time, ratio of drug?:?resin, and temperature. The resinate was evaluated for micromeritic properties and characterized using XRPD and IR. For resinate sustained release tablets were formulated using hydoxypropyl methylcellulose K100M. The tablets were evaluated for hardness, thickness, friability, drug content, weight variation, and in vitro drug release. Tablets thus formulated (Batch T-3) provided sustained release of drug over a period of 12?h. The release of Betahistine HCl from resinate controls the diffusion of drug molecules through the polymeric material into aqueous medium. Results showed that Betahistine HCl was formulated into a sustained dosage form as an alternative to the conventional tablet. PMID:22779010

Wagh, Vijay D; Pawar, Nilesh

2012-01-01

413

Development and Evaluation of Sustained Release Tablet of Betahistine Hydrochloride Using Ion Exchange Resin Tulsion T344  

PubMed Central

An attempt was made to sustain the release of Betahistine hydrochloride by complexation technique using strong cation-exchange resin, Tulsion T344. The drug loading onto ion-exchange resin was optimized for mixing time, activation, effect of pH, swelling time, ratio of drug?:?resin, and temperature. The resinate was evaluated for micromeritic properties and characterized using XRPD and IR. For resinate sustained release tablets were formulated using hydoxypropyl methylcellulose K100M. The tablets were evaluated for hardness, thickness, friability, drug content, weight variation, and in vitro drug release. Tablets thus formulated (Batch T-3) provided sustained release of drug over a period of 12?h. The release of Betahistine HCl from resinate controls the diffusion of drug molecules through the polymeric material into aqueous medium. Results showed that Betahistine HCl was formulated into a sustained dosage form as an alternative to the conventional tablet.

Wagh, Vijay D.; Pawar, Nilesh

2012-01-01

414

Equilibria and heats of exchange of alkaline-earth metal ions on the Na form of mordenite  

Microsoft Academic Search

Sorption-analytic studies of ion exchange equilibria combined with direct calorimetric measurements of the heats of ion exchange\\u000a sorption of the Ca2+, Sr2+, and Ba2+ cations were performed over the whole range of solid phase fillings with sorbed cations on the Na forms of two mordenites\\u000a prepared from natural specimens rich in Na+ and Ca2+ cations. Ion exchange constants were determined

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

2010-01-01

415

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

SciTech Connect

Sorption of beryllium ions by a series of amino-phosphonate amphoteric ion-exchange resins from BeF/sub 2/ solutions containing HF, NH/sub 4/F.HF, and NH/sub 4/F has been studied. The influence of the salt form of the resin, concentration of fluoride ions, and beryllium content in the original solutions was demonstrated. The mechanism of ion exchange on amphoteric ion-exchangers was postulated on the basis of chemical analysis and sorption and IR-spectroscopic data. Conclusions are drawn regarding the participation of phosphorus-containing groups of the resins in exchange. Data are presented on desorption of complex fluoride ions and beryllium from amphoteric ion-exchange resins by solutions of hydrofluoric, hydrochloric, and sulfuric acids, ammonium fluoride, and ammonium hydrogenfluoride.

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

1981-10-20

416

Development of Polarized Hydrogen Ion Source with Resonant Charge-Exchange Plasma Ionizer at INR, Moscow  

NASA Astrophysics Data System (ADS)

Density of unpolarized negative ions in a charge-exchange region of a plasma ionizer of polarized ion source of INR, Moscow has been increased significantly due to development of a two-stage converter of plasma particles into negative ions. Unpolarized D- ion current with a peak intensity of 45 mA has been obtained from the plasma ionizer with the two-stage converter. Respectively, polarized H- ion current of 2.5 mA peak with pulse duration of 150 ?s at 5 Hz rep. rate has been obtained. Further increase of unpolarized negative ion density in the charge-exchange region has been achieved due to improvements in the plasma source design. 90 mA of unpolarized D- ion current and 150 mA of unpolarized H- ion current have been extracted recently from the ionizer. Problems that are necessary to overcome for corresponding increase of polarized ion beam intensity are discussed. It is expected that 4 mA of polarized H- ion current will be obtained from the source after implementation of the improvements described.

Belov, A. S.; Netchaeva, L. P.; Turbabin, A. V.; Vasil'Ev, G. A.

2002-04-01

417

Evaluation of Ion Specific Heat Ratio in a Transonic Plasma Flow  

NASA Astrophysics Data System (ADS)

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

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

2006-10-01

418

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

PubMed

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

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

2008-03-01

419

Effect of quark exchange on the structure function of A = 3 mirror nuclei and neutron/proton structure function ratio  

SciTech Connect

By using quark-exchange formalism and realistic Faddeev wave functions, we investigate deep inelastic electron scattering from A = 3 mirror nuclei. The initial valence quarks input are taken from the GRV's calculations on F{sub 2}{sup P}(x, Q{sup 2}) which gives very good fit to the available data in the (x, Q2)-plane. It is shown that the free neutron to proton structure functions ratio can be extracted from corresponding EMC ratios for 3He and 3H mirror nuclei. The results are in good agreement with other theoretical models as well as present available experimental data.

Zolfagharpour, F.; Modarres, M. [Physics Department, University of Tehran, 1439955961, Tehran (Iran, Islamic Republic of); Yazdanpanah, M.M. [Physics Department, Shahid-Ba-Honar University, Kerman (Iran, Islamic Republic of)

2005-10-26

420

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

NASA Astrophysics Data System (ADS)

Introduction of silver or copper ions in soda-lime silica glass has been investigated by studying the data obtained from optical absorption measurements and the transmission electron microscopy performances. It has been stated that the optical and structural characteristics of the doped specimens are effectively controlled by the dopant concentrations and parameters of both, the ion-exchange procedures and the annealing treatments applied afterwards. By sequential ion exchange of as received specimens in molten baths of Cu2Cl2 and (AgNO3 in NaNO3), the composition and electronic structure of the elemental-nanoclusters have been altered. Moreover, depending on the order of annealing, different microstructures were created in the fabricated composites. Like this, the two-step exchange determines a new engineering way new materials with desired optical properties could be produced.

Suszynska, M.; Krajczyk, L.; Macalik, B.

2010-11-01

421

Laser processing of silver ion-exchanged glass waveguides and applications to integrated optics  

NASA Astrophysics Data System (ADS)

We present a technique to directly process silver ion- exchanged planar waveguides fabricated in soda-lime glass. The technique, that is regarded as complementary to the conventional lithography but with the inherent advantages of the direct processing of the material, is based on laser writing with a focused laser bema from an Ar+ laser, which induces a redistribution and aggregation of the small sliver clusters created in the glass during the ion-exchange process. We give a theoretical explanation of the physical processes that take place in the glass and expose experimental reslut of processing of silver ion-exchanged guides under different irradiation conditions. We expose the possible applications of this technique to integrated optics for 2D waveguiding, to optoelectronics for one-step electrode and waveguide fabrication, to planar optics for patterning of reflective components and to diffractive optics to fabricate conventional elements. We finally demonstrate some of this applications presenting devices fabricated by means of this technique.

Salgueiro, Jose R.; Moreno, Vicente; Linares, Jesus

2000-03-01

422

High intensity source of polarized negative hydrogen ions with resonant charge-exchange plasma ionizer  

NASA Astrophysics Data System (ADS)

The Moscow INR atomic-beam type source of polarized negative hydrogen ions is described. The production of H- ions is based on resonant charge exchange between polarized thermal hydrogen atoms and D- ions in a deuterium plasma. Improvements in the D- plasma source are outlined. The polarized source produces a pulsed H- beam with the peak current up to 1 mA and pulse duration of 180 ?s at repetition rate 10 Hz. The normalized emittance for 90% of the beam particles is 1.8 ? mm mrad. The polarization of low energy H- ions was measured to be 0.87+/-0.02.

Belov, A. S.; Esin, S. K.; Netchaeva, L. P.; Plokhinski, Yu. V.; Vasil'Ev, G. A.; Klenov, V. S.; Turbabin, A. V.; Yakushev, V. P.; Dudnikov, V. G.

1996-07-01

423

Production of Polarized Ions with Nearly Resonant Charge-Exchange Collisions in Plasma  

NASA Astrophysics Data System (ADS)

Review of results of development of polarized ion sources with nearly resonant charge-exchange plasma ionizer is presented. Pulsed beams of polarized protons with peak intensity up to 11 mA and polarization of 80% and polarized negative hydrogen ions with peak current of 4 mA and polarization of 91% have been obtained. Polarized deuterons, negative deuterium ions and 3He++ ions can be produced by this method as well. A study of a pulsed polarized atomic hydrogen beam has been performed. It was found that intensity of the pulsed atomic hydrogen beam is limited by a beam-skimmer interference and by noncomplete cooling of hydrogen atoms.

Belov, A. S.

2008-02-01

424

Synthesis and characterization of nano-composite ion-exchanger; its adsorption behavior  

Microsoft Academic Search

A novel organic–inorganic nanocomposite cation-exchanger has been synthesized via sol–gel method. It was characterized on the basis of FTIR, XRD, SEM, TEM, AFM and Raman studies. The structural studies reveal semi-crystalline nature of the material with the particle size ranging from 1–5nm. Physiochemical properties such as ion-exchange capacity, chemical and thermal stability of composite material have also been determined. Bifunctional

S. A. Nabi; Mohammad Shahadat; Rani Bushra; A. H. Shalla; A. Azam

2011-01-01

425

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

SciTech Connect

The possibility of iron(III) sorption by the amphoteric ion exchanger ANKB-2 from chromate solution and its superiority over the cation exchanger KU-23 (10/60) have been demonstrated. By means of IR spectroscopy it has been shown that iron(III) sorption from chromate solution by ANKB-2 proceeds via both ionic and coordination reactions. The proportion of these kinds of reaction does not depend on the Cr(VI) content of the initial solution.

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

1986-12-20

426

Experiments and data processing of ion exchange equilibria involving Italian natural zeolites: a review  

Microsoft Academic Search

After a historical survey, the present status of research on thermodynamic aspects of ion exchange in Italian natural zeolites, namely phillipsite, chabazite and clinoptilolite, is reported.Equilibrium data relative to exchange reactions between these zeolites and various toxic and noxious cations, namely Cd2+, Pb2+, Cu2+, Zn2+, Cs+, Sr2+, Ba2+, Co2+, NH4+, and two representatives of alkaline and alkaline-earth cations, such as

Domenico Caputo; Francesco Pepe

2007-01-01

427

Reactive Ion Exchange Synthesis of Nano-ZnO and Its Photocatalytic Properties  

Microsoft Academic Search

Nano-crystalline ZnO particles were synthesized by a reactive ion exchange procedure using ZnSO4 and NaOH as precursors and a strong basic anion exchange resin as substrate. The precursors and ZnO samples were characterized by scanning electron microscopy, X-ray diffraction, and UV-Vis spectroscopy. The ZnO particles were club shape, and the synthesis process depended on the reactant concentration of ZnSO4 in

Shaomin ZHU; Zhihong ZHANG

2010-01-01

428

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

429

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

SciTech Connect

Methane is a potent greenhouse gas. It has a global warming potential (GWP) 23 times greater than carbon dioxide. Reducing methane emissions would lead to substantial economic and environmental benefits. This study investigated the performance of multi-transition-metal-(Cu, Cr, Ni, and Co)-ion-exchanged zeolite 13X catalysts in methane emissions abatement. The catalytic activity in methane combustion using multi-ion-exchanged catalysts was studied with different parameters including the molar percentage of metal loading, the space velocity, and the inlet methane concentration under atmospheric pressure and at a relatively low reaction temperature of 500 C. The performance of the catalysts was determined in terms of the apparent activation energy, the number of active sites of the catalyst, and the BET surface area of the catalyst. This study showed that multi-ion-exchanged catalysts outperformed single-ion-exchanged and acidified 13X catalysts and that lengthening the residence time led to a higher methane conversion percentage. The enhanced catalytic activity in the multi-ion-exchanged catalysts was attributed to the presence of exchanged transition ions instead of acid sites in the catalyst. The catalytic activity of the catalysts was influenced by the metal loading amount, which played an important role in affecting the apparent activation energy for methane combustion, the active sites, and the BET surface area of the catalyst. Increasing the amount of metal loading in the catalyst decreased the apparent activation energy for methane combustion and also the BET surface area of the catalyst. An optimized metal loading amount at which the highest catalytic activity was observed due to the combined effects of the various factors was determined. (author)

Hui, K.S.; Chao, C.Y.H.; Kwong, C.W.; Wan, M.P. [Department of Mechanical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

2008-04-15

430

21 CFR 173.20 - Ion-exchange membranes.  

Code of Federal Regulations, 2013 CFR

...following solvents: Distilled water, 5 percent acetic acid, and 50 percent alcohol. Extraction from each sample...production of grapefruit juice to adjust the ratio of citric acid to total solids of the grapefruit juice...

2013-04-01

431

A Lagrangian Model to Predict the Modification of Near-Surface Scalar Mixing Ratios and Air–Water Exchange Fluxes in Offshore Flow  

Microsoft Academic Search

A model was developed to predict the modification with fetch in offshore flow of mixing ratio, air–water exchange flux, and\\u000a near-surface vertical gradients in mixing ratio of a scalar due to air–water exchange. The model was developed for planning\\u000a and interpretation of air–water exchange flux measurements in the coastal zone. The Lagrangian model applies a mass balance\\u000a over the internal

Mark D. Rowe; Judith A. Perlinger; Christopher W. Fairall

2011-01-01

432

The cardiac Na+-Ca2+ exchanger has two cytoplasmic ion permeation pathways  

PubMed Central

The Na+-Ca2+ exchanger (NCX) is a ubiquitously expressed plasma membrane protein. It plays a fundamental role in Ca2+ homeostasis by moving Ca2+ out of the cell using the electrochemical gradient of Na+ as the driving force. Recent structural studies of a homologous archaebacterial exchanger, NCX_Mj, revealed its outward configuration with two potential ion permeation pathways exposed to the extracellular environment. Based on the symmetry of NCX_Mj structure, an atomic model of an inward-facing conformation was generated showing similar pathways but directed to the cytoplasm. The presence of these water-filled cavities has yet to be confirmed experimentally, and it is unknown if the mammalian exchanger adopts the same structure. In this study, we mutated multiple residues within transmembrane segments 2 and 7 of NCX1.1 (cardiac isoform) to cysteines, allowing us to investigate their sensitivity to membrane-impermeable sulfhydryl reagents as exchanger current block. By trapping NCX1.1 in the inward-facing configuration, we have mapped two differently sized cytoplasmic aqueous cavities, the access of which is modified during exchange. This data reveals movements of the protein associated with ion transport. Electrophysiological characterization shows that the conserved residues within transmembrane segments 2 and 7, coordinating Na+ and Ca2+ ions in NCX_Mj, play a fundamental role in NCX1.1. Our results suggest a similar architecture between the mammalian and archaebacterial exchangers.

John, Scott A.; Liao, Jun; Jiang, Youxing; Ottolia, Michela

2013-01-01

433

Cation-exchange of metal ions in organic solvent-cupferron media.  

PubMed

Distribution coefficients of 20 metal ions were determined on the strongly acidic cation-exchanger Dowex 50 in a 30:7:1 mixture of chloroform-methanol-lM hydrochloric acid which was 0.1M in cupferron. In this system the distribution coefficients of Fe(in), Ti(TV), Cu(II), Ce(III) and Th are lower by several orders of magnitude than those of Ni, Mn(II), Cd, Co(II), Ca, U(VI), and Sr. It is possible to separate these two groups of elements on an ion-exchange column. PMID:18961228

Korkisch, J; Khater, M M

1972-12-01

434

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

435

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

436

Channel waveguides on RbTiOPO4 by Cs+ ion exchange.  

PubMed

In this Letter we report Cs(+) ion exchange channel waveguides on RbTiOPO(4) (RTP) for what we believe is the first time. A Ti channel mask was fabricated on an RTP substrate by conventional photolithography. The ion exchange process was carried out in a CsNO(3) melt, and the channels produced ranged from 6 to 11 ?m in width. The near-field pattern of the modes was recorded, and type II second harmonic generation in waveguide regime was obtained, producing 512.5 nm green light. The optical characterization shows optical losses of 3.8 dB/cm. PMID:23381425

Cugat, J; Solé, R; Carvajal, J J; Mateos, X; Massons, J; Lifante, G; Díaz, F; Aguiló, M

2013-02-01

437

Experimental and Modeling Study of Ion Exchange Between Aqueous Solutions and the Zeolite Mineral Clinoptilolite  

Microsoft Academic Search

Ion-exchange experiments were conducted at 25°C between the zeolite mineral clinoptilolite and aqueous solutions of Na+\\/Sr2+ (0.005, 0.05, and 0.5 N), K+\\/Sr2+ (0.05N), and K+\\/Ca2+ (0.05 N). The isotherm data were used to derive equilibrium constants and Gibbs energies for the ion-exchange reactions and Margules parameters for the zeolite solid solution. The Margules model, in combination with the Pitzer equations

Roberto T. Pabalan; F. Paul Bertetti

1999-01-01

438

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

SciTech Connect

Resin denitration via anion-exchange is an implementable process that can effectively mitigate the hazards associated with stored resins in which the bulk of the nitrate consists of an "exchangeable nitrate" ionically bound to the cationic sites of the anion-exchange resins. Salicylate has been selected as the exchange anion of choice because of its superior selectivity for the Rocky Flats resins and its unique potential for comprehensive recovery and recycle. This report outlines a single recommended resin denigration procedure that is reasonably independent of the resin composition and the current stored form. This procedure is not optimized but rather seeks to `over-treat' the resins so that a single procedure works for the variety of stored resins. The recommended treatment with sodium salicylate reduces resins by 95-99+% the measured exothermic behavior of the ion-exchange.

Jacob Espinoza; Mary Barr; Wayne Smith

1998-12-01

439

Corrosion of steel drums containing cemented ion-exchange resins as intermediate level nuclear waste  

NASA Astrophysics Data System (ADS)

Exhausted ion-exchange resins used in nuclear reactors are immobilized by cementation before being stored. They are contained in steel drums that may undergo internal corrosion depending on the presence of certain contaminants. The objective of this work is to evaluate the corrosion susceptibility of steel drums in contact with cemented ion-exchange resins with different aggressive species. The corrosion potential and the corrosion rate of the steel, and the electrical resistivity of the matrix were monitored for 900 days. Results show that the cementation of ion-exchange resins seems not to pose special risks regarding the corrosion of the steel drums. The corrosion rate of the steel in contact with cemented ion-exchange resins in the absence of contaminants or in the presence of 2.3 wt.% sulphate content remains low (less than 0.1 ?m/year) during the whole period of the study (900 days). The presence of chloride ions increases the corrosion rate of the steel at the beginning of the exposure but, after 1 year, the corrosion rate drops abruptly reaching a value close to 0.1 ?m/year. This is probably due to the lack of water to sustain the corrosion process. When applying the results obtained in the present work to estimate the corrosion depth of the steel drums containing the cemented radioactive waste after a period of 300 years, it is found that in the most unfavourable case (high chloride contamination), the corrosion penetration will be considerably lower than the thickness of the wall of the steel drums. Cementation of ion-exchange resins does not seem to pose special risks regarding the corrosion of the steel drums that contained them; even in the case the matrix is highly contaminated with chloride ions.

Duffó, G. S.; Farina, S. B.; Schulz, F. M.

2013-07-01

440

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

441

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

442

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

443

RADIOMETRIC EXTRACTION METHOD FOR FLUORIDE. PYROLYSIS-ION EXCHANGE SEPARATION  

Microsoft Academic Search

In many liquid-liquid extraction systems, complexing anions cause ; lowered extraction of metal ions. The potentiality of using this as the basis ; for determining anions has been investigated with the system hafnium-; fluoridetrioctylphosphine oxide. An inverse linear response was obtained for ; hafnium extraction vs. fluoride concentration for 2 to 10 mu moles of fluoride. ; Hafnium distribution is

W. J. Maeck; G. L. Booman; M. C. Elliott; J. E. Rein

1960-01-01

444

Recovering gold from thiosulfate leach pulps via ion exchange  

NASA Astrophysics Data System (ADS)

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

Nicol, Michael J.; O'Malley, Glen

2002-10-01

445

Investigation of phosphate removal using sulphate-coated zeolite for ion exchange.  

PubMed

Sulphate-coated zeolite (SCZ) was characterized and employed for the removal of phosphate from aqueous solutions using both batch and column tests. Batch experiments were conducted to assess the sulphate dilution ratio, reaction time for coating, surface washing and calcination temperature during the synthesis of SCZ. Langmuir isotherm and pseudo-first-order models were suitable to explain the sorption characteristics of phosphate onto the SCZ. Equilibrium tests showed that SCZ was capable of removing phosphate, with a maximum binding energy beta = 30.2 mg g(-1), compared to other adsorbents, such as activated alumina and ion exchange resin. The Thomas model was applied to the adsorption of phosphate to predict the breakthrough curves and the parameters of a column test. The model was found to be suitable for describing the adsorption process of the dynamic behaviour of the SCZ column. The total adsorbed quantity and equilibrium uptake ofphosphate related to the effluent volumes were determined by evaluating the breakthrough curves obtained under the allowed conditions. The results of batch and column experiments, as well as the low cost of the adsorbent, suggested that SCZ could be used as an adsorbent for the efficient and cost-effective removal of phosphate from aqueous solution. PMID:23393974

Choi, Jae-Woo; Hong, Seok-Won; Kim, Dong-Ju; Lee, Sang-Hyup

2012-01-01

446

Ion-exchange liquid chromatographic analysis of bisphosphonates in pharmaceutical preparations.  

PubMed

A simple, fast and uniform method has been developed for the quantitative determination of bisphosphonates in the quality control of pharmaceutical preparations. The method is based on ion-exchange liquid chromatography with conductivity detection. Separation is performed on a Waters IC-PAK Anion column using 2 mM nitric acid or 25 mM succinic acid as the mobile phase. Retention of the bisphosphonates can be influenced by pH and the anion concentration of the mobile phase. Sensitivity and selectivity are sufficient for the assay of bisphosphonates in bulk drug and pharmaceutical preparations. Sample preparation comprises dissolution or dilution of the sample in the mobile phase followed, if necessary, by filtration prior to HPLC analysis. Since the method is stability indicating, it is also well suited for shelf-life studies of bisphosphonate pharmaceutical preparations. Validation of the analytical method for the assay of pamidronate injection indicated an intra-day reproducibility of 1.7% (n = 6) and an inter-day reproducibility of 2.7% (n = 6). A linear relationship between response and concentration was found in the concentration range studied from 200 ng to 10 micrograms pamidronate per 20 microliters injected. The lower limit of detection (signal-to-noise ratio = 3) of pamidronate was about 100 ng. PMID:8305603

Den Hartigh, J; Langebroek, R; Vermeij, P

1993-10-01

447

Ion exchange\\/adsorption properties of crystalline compound of anatase and rutile  

Microsoft Academic Search

The crystallinely hydrous titanium dioxide, H4Ti3O8, was synthesized by heating amorphous titanium hydroxide at 80°C for 12 hours. XRD, TGA and pH titration were employed to characterize the prepared crystal. The studies on acid, base and radiation stabilities of the crystal demonstrate the reliability of this type of ion exchange material for treating radioactive nuclear wastes. The uranyl ions are

Song Yinjie; Jiang Liqiang; Zhao Aimin; Jin Qixin; Song Dalkang

1997-01-01

448

A simple ion-exchange resin procedure for extracting plant-available elements from soil  

Microsoft Academic Search

A simplified procedure for extracting ions from soil with ion-exchange resins is reported. The resin, placed in nylon-netting bags, were immersed in soil suspensions and shaken. Compared to the conventional procedure, where the resin beads are freely suspended in the soil-water mixture, this bag-procedure allowed quicker separation of resin from the soil suspensions. Furthermore, the severe soil grinding as done

E. Sibbesen

1977-01-01

449

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

SciTech Connect

In studies of sorption of beryllium ions from BeSO4 solutions by a series of aminocarboxylic polyampholytes the influence of pH and of the H2SO4, (NH4)2SO4, and BeSO4 concentrations was demonstrated. The mechanism of the process is postulated on the basis of sorption data and the results of IR-spectroscopic studies. It is concluded that carboxyl groups of polyampholytes take part in ion exchange.

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

1986-05-10

450

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

451

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

Microsoft Academic Search

Accurate studies of low-energy charge exchange (CX) are critical to understanding underlying soft X-ray radiation processes in the interaction of highly charged ions from the solar wind with the neutral atoms and molecules in the heliosphere, cometary comas, planetary atmospheres, interstellar winds, etc.. Particularly important are the CX cross sections for bare, H-like, and He-like ions of C, N, O

I. N. Draganic´; D. G. Seely; D. McCammon; C. C. Havener

2011-01-01

452

Ion Exchange Characteristics of Palladium and Ruthenium from a Simulated Radioactive Liquid Waste  

Microsoft Academic Search

Radioactive high-level liquid wastes contain significant quantities of platinum group metals (PGM), such as palladium [Pd(II)], rhodium [Rh(III)], and ruthenium [Ru(III)]. The PGM are produced as fission products in nuclear reactors. In this study, batch and column experiments were carried out to investigate the ion exchange characteristics of Pd(II) and Ru(III), including the effects of the ionic group of ion

S. H. Lee; H. Chung

2003-01-01

453

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

NASA Astrophysics Data System (ADS)

Due to their large trap depths (˜1 eV or 10,000 K), versatility, and ease of construction, Paul traps have important uses in high-resolution spectroscopy, plasma physics, and precision measurements of fundamental constants. An ion-neutral hybrid trap consisting of two separate but spatially concentric traps [a magneto-optic trap (MOT) for the neutral species and a mass-selective linear Paul trap for the ionic species] is an ideal apparatus for sympathetic cooling. However, over the past few years, hybrid traps have proven most useful in measuring elastic and charge-exchange rate constants of ion-neutral collisions over a wide temperature range from kilo-Kelvin to nano-Kelvin. We report some initially surprising results from a hybrid trap system in our laboratory where we have loaded the Paul trap with Ca+ ions in the presence of a Na MOT (localized dense gas of cold Na atoms). We find a strong loss of Ca+ ions with MOT exposure, attributed to an exothermic, non-resonant ion-neutral charge-exchange process with an activation barrier, which leads to the formation of Na+ ions. We propose a detailed mechanism for this process. We obtain an estimated measure of the rate constant for this charge exchange of ˜2 × 10-11 cm3/s, much less than the Langevin rate, which suggests that the Langevin assumption of unit efficiency in the reaction region is not correct in this case.

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

2014-01-01

454

Charge exchange and chemical reactions with trapped thorium ions  

NASA Astrophysics Data System (ADS)

Most atomic nuclei have excitation energies ranging from keV to MeV. A unique exception is the ^229Th nucleus, which has an excited state just several eV above the nuclear ground state.ootnotetextB. R. Beck et al., Phys. Rev. Lett. 98, 142501 (2007). Th^3+ provides a convenient level structure for laser cooling in an rf Paul trap.ootnotetextC. J. Campbell et al., Phys. Rev. Lett 102, 233004 (2009). Unlike many ions commonly utilized in precision measurements, the trap lifetime of Th^3+ is limited to only several minutes. This is a severe limitation to experiments involving ^229Th as it is only available in minute quantities. Here we have studied the loss mechanisms by introduction of various contaminants and analyzed reaction products using trapped ion mass spectrometry techniques.ootnotetextL. R. Churchill et al., Phys. Rev. A 83, 012710 (2011).

Depalatis, Michael; Churchill, Layne; Chapman, Michael

2011-06-01

455

Nitrogen removal by ion exchange: biological regeneration of clinoptilolite  

Microsoft Academic Search

A small-scale, pilot-plant study, in which a slurry of nitrifying bacteria in a 300 meq\\/l. salt solution was recirculated through a column of exhausted clinoptilolite that had been used to remove ammonium ion from a synthetic waste water, showed that the biological process provided reproducible column performance in short regeneration times (about two hours); the rate of biological regeneration was

A. C. Booth; J. T. Wang; M. J. Semmens

1977-01-01

456

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

457

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

NASA Astrophysics Data System (ADS)

Global magnetic reconnection events in the MST reversed field pinch (RFP) result in significant ion heating and acceleration. It is well understood that the ultimate energy source is the equilibrium magnetic energy, but the exact mechanism of the conversion of magnetic energy to particle kinetic energy is a topic of continuing research. In a recent experiment, we measured the temperature evolution of various charge states of dominant impurity ions in MST (Al, C, N and O), using passive spectroscopy. Measurements are made in standard RFP discharges with plasma current, Ip˜400 kA and central line averaged electron density, ne˜1.0x10^19 m-3. Temperatures of these impurity ions are measured at the edge of the plasma, predominantly in the direction parallel to the equilibrium magnetic field. It is found that the increase in ion temperature during magnetic reconnection events is proportional to the charge-to-mass ratio of the ion species. Consistency with existing theoretical models for ion heating is investigated.

Kumar, S. T. A.; den Hartog, D. J.; Nornberg, M. D.; Almagri, A. F.; Sarff, J. S.; Craig, D.

2012-10-01

458

Observation and implications of high mass-to-charge ratio ions from electrospray ionization mass spectrometry  

Microsoft Academic Search

High mass-to-charge ratio ions (> 4000) from electrospray ionization (ESI) have been observed for several proteins, including\\u000a bovine cytochrome c (M\\u000a r 12,231) and porcine pepsin (M\\u000a r 34,584), by using a quadrupole mass spectrometer with an m\\/z 45,000 range. The ESI mass spectrum for cytochrome c in an aqueous solution gives a charge state distribution that ranges from 12

Brian E. Winger; Karen J. Light-Wahl; Rachel R. Ogorzalek Loo; Harold R. Udseth; Richard D. Smith

1993-01-01

459

LIQUID MIXING IN A LARGE-SIZED COLUMN OF ION EXCHANGE  

Microsoft Academic Search

Several different liquid distributors were manufactured and separately attached to the top of a large-sized, 50 cm i. d. ion exchange column. Effective dispersion coefficients of these distributors were measured by the stepwise response method, and were compared with those of smaller-sized columns. It was found that the use of an appropriate distributor enables one to scale up the column

S. FUJINE; K. SAITO; K. SHIBA; T. ITOI

1983-01-01

460

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...

461

Formulation, Characterization and Evaluation of Rapid Disintegrating Tablet of atifloxacin Sesquihydrate by ion exchange resin technique  

Microsoft Academic Search

Gatifloxacin Sesquihydrate is a Broad Spectrum Antimicrobial agent active against Gram Positive and Gram Negative Organism. It is slightly bitter in taste. In the present study an attempt has been made to prepare bitterless fast dissolving tablet of Gatifloxacin Sesquihydrate using Indion 204, Indion 214, Indion 234, Tulsion 335 (ion exchange resin) as a taste masking agent. X-ray powder diffractometry,

P. S. Gangane; K. G. Mahajan; H. S. Sawarkar; V. S. Adhao

462

WASTEWATER DEMINERALIZATION BY TWO-STAGE FIXED-BED ION EXCHANGE PROCESS  

EPA Science Inventory

A 9.5 l/min (2.5 gpm) two-stage fixed bed ion exchange process (primary cation - primary anion - secondary cation - secondary anion) was operated on a feed of carbon treated secondary effluent for 48 months at Pomona, California. To achieve high levels of regeneration efficiency ...

463

THE REMOVAL OF STRONTIUM AND CESIUM FROM SIMULATED HANFORD GROUNDWATER USING INORGANIC ION EXCHANGE MATERIALS  

Microsoft Academic Search

A number of inorganic ion exchange materials that are commercially available or under development were evaluated for the removal of strontium and cesium from a simulated groundwater found in the Hanford waste storage area using a groundwater simulant spiked with either 89Sr or 137 Cs. The most promising materials for strontium were found to be a sodium titanosilicate from Texas

Paul Sylvester; Abraham Clearfield

1998-01-01

464

The Effects of Sulfonated Poly(ether ether ketone) Ion Exchange Preparation Conditions on Membrane Properties  

PubMed Central

A low cost cation exchange membrane to be used in a specific bioelectrochemical system has been developed using poly(ether ether ketone) (PEEK). This material is presented as an alternative to current commercial ion exchange membranes that have been primarily designed for fuel cell applications. To increase the hydrophilicity and ion transport of the PEEK material, charged groups are introduced through sulfonation. The effect of sulfonation and casting conditions on membrane performance has been systematically determined by producing a series of membranes synthesized over an array of re