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Sample records for anion exchange chromatography

  1. Test procedure for anion exchange chromatography

    International Nuclear Information System (INIS)

    Plutonium from stored nitrate solutions will be sorbed onto anion exchange resins and converted to storable plutonium dioxide. Useful information will be simultaneously gained on the thermal stability and ion exchange capacity of four commercially available anion exchange resins over several years and under severe degradative conditions. This information will prove useful in predicting the safe and efficient lifetimes of these resins

  2. The assessment of pellicular anion-exchange resins for the determination of anions by ion chromatography

    International Nuclear Information System (INIS)

    Because pellicular anion-exchange resins suitable for the determination, by ion chromatography, of anions with alkaline eluents were unavailable in South Africa at the inception of this work, an attempt was made to prepare such resins. In this study it is shown that the pellicular resins produced are more efficient than the surface-aminated resins used previously. The simultaneous separation and determination of five common anions is demonstrated. The method was applied to the analysis of uranium leach liquors, effluent samples, and a solid sample of ferric oxide (goethite)

  3. Uranium isotope separation by continuous anion exchange chromatography

    International Nuclear Information System (INIS)

    This paper reports a process for producing nuclear quality Uranium 235 (U235) from a substantially impure feed stock containing a mixture of uranium isotopes, including U235, forming a stationary phase from an anion exchange resin in the annulus of a rotating annular chromatograph; feeding the feed stock to the stationary phase to load less than 10% of the stationary phase; injecting a mobile phase comprising an eluant selected from the group consisting of aqueous solutions of sulfates, chlorides, nitrates and carbonates into the stationary phase; continuously rotating the annular chromatograph; collecting the U235 isotope in substantially pure, enriched form from the stationary phase; precipitating the U235 isotope as ammonium diurante with ammonium hydroxide; and calcining the ammonium diuranate to produce uranium oxide rich in U235 suitable for nuclear applications requiring substantially pure U235

  4. Boron isotope separation by ion exchange chromatography using weakly basic anion exchange resin

    International Nuclear Information System (INIS)

    Isotopic plateau displacement chromatography, a useful method for isotope separation is presented. The boric acid band formed in a column of weakly basic anion exchange resin Diaion WA21 can be eluted with pure water. In order to obtain good accumulation of the isotope effect, a series of experiments with different migration length were carried out. The boron-10 enriched part of the boric acid absorbed band was always preceded by the isotopic plateau part, in which the atomic fraction of boron-10 was maintained at its original value. The atomic fraction of boron-10 at the end of the chromatogram increased with migration length, and in the case of 256-m migration, boron-10 was enriched from its original atomic fraction of 19.84 to 91.00%, the separation factor S being constant irrespective of migration length: S = 1.0100 +- 0.0005. (author)

  5. Separation of boron isotopes by ion exchange chromatography: studies on regeneration of strong base anion exchange resins

    International Nuclear Information System (INIS)

    The optimum conditions for the regeneration of strong base anion exchange resins of type-I and type-II were determined for cost-effective separation of isotopes of boron by ion exchange chromatography where the hydroxyl form of an anion exchange resin is equilibrated with boric acid solution containing mannitol as a complexing reagent. The possibility of using unspent alkali content of the effluent was also exploited. Removal of carbonate impurity from Rayon grade caustic lye (used as regenerant after dilution) and recycling of Ba(OH)2 was studied to avoid waste disposal problems. (author)

  6. Preparation and chromatographic performance of polymer-based anion exchangers for ion chromatography: A review.

    Science.gov (United States)

    Zatirakha, A V; Smolenkov, A D; Shpigun, O A

    2016-01-21

    In the last decade the developments in the field of ion chromatography (IC) were aimed at increasing the efficiency, sensitivity and rapidity of analysis, as well as on improving separation selectivity. Since selectivity and efficiency to the large extent depend on the surface chemistry of the stationary phase, the development of novel anion exchangers remains one of the priority tasks in modern IC. The exact chemistry of commercially available resins is not known and not many literature data devoted to the procedures of preparing anion exchangers for IC have become available in the last 10-15 years. However, the knowledge about the surface chemistry of anion exchangers can provide understanding of the trends in selectivity and efficiency changes, as well as help with the choice of the stationary phase type suitable for solving a particular analytical task. The current review is devoted to the methods of preparing anion exchangers based on polystyrene-divinylbenzene (PS-DVB) and ethylvinylbenzene-divinylbenzene (EVB-DVB) for IC of inorganic and small organic anions and is aimed at demonstrating the improvement of their performance over the years, which was brought by the development of the new types of stationary phase architecture. PMID:26724761

  7. Rapid detection of malto-oligosaccharide-forming bacterial amylases by high performance anion-exchange chromatography

    DEFF Research Database (Denmark)

    Duedahl-Olesen, Lene; Larsen, K. L.; Zimmermann, W.

    2000-01-01

    High performance anion-exchange chromatography with pulsed amperometric detection was applied for the rapid analysis of malto-oligosaccharides formed by extracellular enzyme preparations from 49 starch-degrading bacterial strains isolated from soil and compost samples. Malto-oligosaccharide-formi......-oligosaccharide-forming amylases, indicated by a predominant formation of maltohexaose from starch, were produced by enzyme preparations from four of the isolates growing at pH 7.0 and 10....

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

    Science.gov (United States)

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

    2015-08-21

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

  9. Determination of petroleum sulfonates in crude oil by column-switching anion-exchange chromatography

    Institute of Scientific and Technical Information of China (English)

    Liang Zhao; Xu Long Cao; Hong Yan Wang; Xia Liu; Sheng Xiang Jiang

    2008-01-01

    A column-switching anion-exchange chromatography method was described for the separation and determination of petroleum monosulfonates (PMS)and petroleum disulfonates (PDS)in crude oil that was simply diluted with the dichloromethane/methanol (60140).The high performance liquid chromatography (HPLC)system consisted of a clean-up column and an analytical column,which were connected with two six-port switching valves.Detection of petroleum sulfonates was available and repeatable.This method has been successfully applied to determine PMS and PDS in crude oil samples from Shengli oil field.

  10. Mono- and polyprotic buffer systems in anion exchange chromatography of influenza virus particles.

    Science.gov (United States)

    Vajda, Judith; Weber, Dennis; Stefaniak, Sabine; Hundt, Boris; Rathfelder, Tanja; Müller, Egbert

    2016-05-27

    Different ions typically used in downstream processing of biologicals are evaluated for their potential in anion exchange chromatography of an industrially produced, pandemic influenza H1N1 virus. Capacity, selectivity and recovery are investigated based on single step elution parallel chromatography experiments. The inactivated H1N1 feedstream is produced in Madin-Darby Bovine Kidney cells. Interesting effects are found for sodium phosphate and sodium citrate. Both anions are triprotic kosmotropes. Anion exchange chromatography generally offers high scalability to satisfy sudden demands for vaccines, which may occur in case of an emerging influenza outbreak. Appropriate pH conditions for H1N1 adsorption are determined by Zeta potential measurements. The dynamic binding capacity of a salt tolerant polyamine-type resin is up to 6.4 times greater than the capacity of a grafted Q-type resin. Pseudo-affinity interactions of polyamines with the M2 protein of influenza may contribute to the obtained capacity increase. Both resins achieve greater capacity in sodium phosphate buffer compared to Tris/HCl. A recovery of 67% and DNA clearance close to 100% without DNAse treatment are achieved for the Q-type resin. Recovery of the virus from the salt tolerant resin requires the use of polyprotic acids in the elution buffer. 85% of the DNA and 60% of the proteins can be removed by the salt tolerant resin. The presence of sodium phosphate during anion exchange chromatography seems to support stability of the H1N1 particles in presence of hydrophobic cations. PMID:27130581

  11. Separation and determination of alditols and sugars by high-pH anion-exchange chromatography with pulsed amperometric detection

    DEFF Research Database (Denmark)

    Andersen, Rikke; Sørensen, A.

    Carbohydrates such as alditols (polyols or sugar alcohols), monosaccharides and disaccharides are separated as anions by anion-exchange chromatography with a sodium hydroxide eluent, MA1 CarboPac column and pulsed amperometric detection. We report a high-pH anion-exchange chromatographic-pulsed a......Carbohydrates such as alditols (polyols or sugar alcohols), monosaccharides and disaccharides are separated as anions by anion-exchange chromatography with a sodium hydroxide eluent, MA1 CarboPac column and pulsed amperometric detection. We report a high-pH anion-exchange chromatographic......-pulsed amperometric detection (HPAEC-PAD) method that determines all the polyols used as food additives in food products and the most commonly found mono- and disaccharides on a routine basis. The linearity, repeatability, internal reproducibility and accuracy are described. The applicability of the method has been...

  12. Copper modified platinum electrode for amperometric detection of spectinomycin sulfate by anion-exchange chromatography

    Institute of Scientific and Technical Information of China (English)

    Ling Ling Xi; Pei Min Zhang; Yan Zhu

    2009-01-01

    A La~(3+)-Cu/Pt modified electrode was fabricated by electrodepositing process in CuSO_4 solution by adding a small amount of lanthium compound, and it was employed for direct current (DC) amperometric detection of spectinomycin by anion-exchange chromatography. Without derivatization, this method can simultaneously determine the main component and impurities in spectinomycin pharmaceutical raw material. Ease of preparation, being applied in DC detection mode and good catalytic stability confirmed the interests of this modified electrode as amperometric sensor for the determination of spectinomycin.

  13. Purification system of gram-amount neptunium using anion exchange chromatography

    International Nuclear Information System (INIS)

    To develop a purification system of gram-amount neptunium using anion exchange chromatography, adsorption elution of excess amount of actinium in 6M HNO3 aqueous solution was studied using thorium and uranium tracer. The partition coefficient (Kd) of Th (IV) decreased from Kd=99.1 of tracer to Kd=44.0, 5% load. By decreasing the partition coefficient, we can wash until 30 Vs under the purification conditions of 1% load and 95% recovery. The retention volume of U (IV) was about 300 Vs, a large value. The partition coefficient of Np (IV) may be larger than it and the large amount of washable eluting solution may be obtained. Washing of impurity of 3d transition metal and actinide (VI) can be done until 20Vs. With washing of 150Vs, impurity of alkali earth metal, metals (III) and platinum group metals decreased less than 0.1%. (S.Y.)

  14. Analysis of human milk oligosaccharides using high-performance anion-exchange chromatography with pulsed amperometric detection

    DEFF Research Database (Denmark)

    Lie, Aleksander; Pedersen, Lars Haastrup

    lacto-N-neotetraose (Galβ1-4GlcNAcβ1-3Galβ1-4Glc), among others. High-performance anion-exchange chromatography (HPAE) with pulsed amperometric detection (PAD) is an analysis method highly suited for carbohydrates. HPAE with alkaline eluents results in retention of neutral carbohydrates depending on the...

  15. Anion-exchange high-performance liquid chromatography with conductivity detection for the analysis of phytic acid in food

    OpenAIRE

    Talamond, Pascale; Doulbeau, Sylvie; Rochette, Isabelle; Guyot, Jean-Pierre; Trèche, Serge

    1999-01-01

    A sensitive method for the accurate determination of phytic acid in food samples is described. The proposed procedure involves the anion-exchange liquid chromatography with conductivity detection. Initially, two methods of determination of phytic acid were compared : absorptiometry and high-performance ion chromatography (HPIC) with chemically suppressed conductivity detector. Unlike most conventional methods involving precipitation by FeCl3, the simpler and more reliable HPIC assay avoids th...

  16. Quantitative compositional analysis of heparin using exhaustive heparinase digestion and strong anion exchange chromatography

    Directory of Open Access Journals (Sweden)

    Pierre Mourier

    2015-03-01

    Full Text Available Heparin is a linear sulfated polysaccharide widely used therapeutically as an anticoagulant. It is also the starting material for manufacturing low-molecular-weight heparins (LMWH. Quality control of heparin and LMWH is critical to ensure the safety and therapeutic activity of the final product. However due to their complex and heterogeneous structure, orthogonal analytical techniques are needed to characterize the building blocks of heparin. One of the state-of-the-art methods for heparin analysis is based on complete enzymatic digestion using a mixture of heparinases I, II, and III, followed by the separation of the resulting oligosaccharides by liquid chromatography. The European Pharmacopoeia strong anion-exchange chromatographic method, used to quantify 1,6-anhydro derivatives in enoxaparin, is here applied to the analysis of the heparin building blocks. Their quantification, namely the determination of their average w/w percentage in the heparin chain, is obtained after identification of all components including glycoserine derivatives and 3-O sulfated di- and tetrasaccharides. This work therefore provides a comprehensive overview of the building blocks of unfractionated heparin, including those chemically modified by the manufacturing process, either within the polysaccharide chain or at its reducing end.

  17. Boron isotope separation by ion exchange chromatography using weakly basic anion exchange resin

    International Nuclear Information System (INIS)

    Influences of operating temperatures and concentrations of feed boric acid solutions were examined on the above titled process over the ranges of 25 - 70 0C and 0.1 - 1.6 mol/dm3 (M), respectively. The ideal displacement chromatography with a very sharp-cut boundary of the boric acid adsorption band was realized at higher temperatures and lower boric acid concentrations within the experimental conditions. The isotope separation coefficient epsilon was found to decrease with increases in either temperature or the boric acid concentration. The observed values of epsilon at 25 0C were 0.013, 0.012 and 0.011 corresponding to feed boric acid concentrations of 0.1 M, 0.4 M and 0.8 M, respectively. The epsilon's at 70 0C were 0.0097 (0.1 M), 0.0086 (0.4 M), 0.0083 (0.8 M) and 0.0073 (1.6 M). A temperature of 40 0C and 0.4 M of boric acid concentration was considered the optimum operating condition for the production of enriched 10B. (author)

  18. Wheat gluten amino acid analysis by high-performance anion-exchange chromatography with integrated pulsed amperometric detection.

    Science.gov (United States)

    Rombouts, Ine; Lagrain, Bert; Lamberts, Lieve; Celus, Inge; Brijs, Kristof; Delcour, Jan A

    2012-01-01

    This chapter describes an accurate and user-friendly method for determining amino acid composition of wheat gluten proteins and their gliadin and glutenin fractions. The method consists of hydrolysis of the peptide bonds in 6.0 M hydrochloric acid solution at 110°C for 24 h, followed by evaporation of the acid and separation of the free amino acids by high-performance anion-exchange chromatography with integrated pulsed amperometric detection. In contrast to conventional methods, the analysis requires neither pre- or postcolumn derivatization, nor a time-consuming oxidation or derivatization step prior to hydrolysis. Correction factors account for incomplete release of Val and Ile even after hydrolysis for 24 h, and for losses of Ser during evaporation. Gradient conditions including an extra eluent allow multiple sequential sample analyses without risk of Glu accumulation on the anion-exchange column which otherwise would result from high Gln levels in gluten proteins. PMID:22125156

  19. Anion exchange membrane

    Science.gov (United States)

    Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

    2013-05-07

    An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

  20. Comparison of displacement versus gradient mode for separation of a complex protein mixture by anion-exchange chromatography.

    Science.gov (United States)

    Ahrends, Robert; Lichtner, Björn; Buck, Friedrich; Hildebrand, Diana; Kotasinska, Marta; Kohlbacher, Oliver; Kwiatkowski, Marcel; Wagner, Moritz; Trusch, Maria; Schlüter, Hartmut

    2012-07-15

    Liquid chromatography is often the method of choice for the analysis of proteins in their native state. Nevertheless compared to two-dimensional electrophoresis, the resolution of common chromatographic techniques is low. Liquid chromatography in the displacement mode has previously been shown to offer higher resolution and to elute proteins in the high concentrations. In this study we compared to what extend displacement mode was a suitable alternative to gradient mode for the separation of a complex protein mixture using anion-exchange displacement chromatography and if it is therefore helpful for proteomic investigations. Hence we analyzed the qualitative protein composition of each fraction by tryptic digestion of the proteins, analysis of the tryptic peptides by liquid chromatography coupled to mass spectrometry followed by data base analysis and by measuring the elution profiles of 22 selected proteins with selected reaction monitoring mass spectrometry. In the fractions of displacement mode a significantly higher number of identified proteins (51 versus 16) was yielded in comparison to gradient mode. The resolution of displacement chromatography was slightly lower than of gradient chromatography for many but not for all proteins. The selectivities of displacement mode and gradient mode are very different. In conclusion displacement chromatography is a well suited alternative for top-down proteomic approaches which start with separating intact proteins first prior to mass spectrometric analysis of intact or digested proteins. The significant orthogonality of both modes may be used in the future for combining them in multidimensional fractionation procedures. PMID:22727752

  1. Refolding with Simultaneous Purification of Recombinant Human Granulocyte Colony-stimulating Factor from Escherichia coli Using Strong Anion Exchange Chromatography

    Institute of Scientific and Technical Information of China (English)

    Chao Zhan WANG; Jiang Feng LIU; Xin Du GENG

    2005-01-01

    The urea denatured recombinant human granulocyte colony-stimulating factor (rhGCSF) which was expressed in Escheriachia coli (E. coli) was refolded with simultaneous purification by strong anion exchange chromatography (SAX) in the presence of low concentration of urea. The effect of urea concentration on this refolding process was investigated. The obtained refolded rhG-CSF has a high specific activity of 2.3×108 U/mg, demonstrating that the proteins were completely refolded during the chromatographic process. With only one step by SAX in 40 min, purity and mass recovery of the refolded and purified rhG-CSF were 97% and43%, respectively.

  2. Simultaneous Determination of Anions and Cations in Natural Water by Ion-exclusion/Cation-exchange Chromatography with a Weakly Acidic Cation-exchange Resin Column

    International Nuclear Information System (INIS)

    The simultaneous determination of anions (SO4 2-, Cl-, and NO3 -) and cations (Na+, NH4+, K+, Mg2+, and Ca2+) in natural water obtained by Nakdong River waters system in Korea were performed by ion-exclusion/cation exchange chromatography with conductimetric detection. The stationary phase was a polymethacrylate-based weakly acidic cation-exchange resin column in the H+-form and a weak-acid eluent. When using only a 1.4 mM sulfosalicylic acid/6 mM 18-crown-6 ether as an eluent, good resolution of both anions and cations, minimum time required for the separation, and satisfactory detection sensitivity were obtained in a reasonable time. The method was successfully applied to the simultaneous determination of anions and cations in natural waters

  3. Simultaneous Determination of Anions and Cations in Natural Water by Ion-exclusion/Cation-exchange Chromatography with a Weakly Acidic Cation-exchange Resin Column

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kwang Pill; Choi, Seong Ho; Park, Yu Chul; Bae, Zun Ung; Lee, Mu Sang; Lee, Sang Hak; Chang, Hye Yong [Graduate School, Kyungpook National University, Daegu (Korea, Republic of); Kwon, Se Mok [Ulsan City Health and Environmental Research Institute, Ulsan (Korea, Republic of); Tanaka, Kazuhiko [National Industrial Research Institute of Nagoya, Nagoya (Japan)

    2003-09-15

    The simultaneous determination of anions (SO{sub 4} {sup 2-}, Cl{sup -}, and NO{sub 3} {sup -}) and cations (Na{sup +}, NH{sup 4+}, K{sup +}, Mg{sup 2+}, and Ca{sup 2+}) in natural water obtained by Nakdong River waters system in Korea were performed by ion-exclusion/cation exchange chromatography with conductimetric detection. The stationary phase was a polymethacrylate-based weakly acidic cation-exchange resin column in the H{sup +}-form and a weak-acid eluent. When using only a 1.4 mM sulfosalicylic acid/6 mM 18-crown-6 ether as an eluent, good resolution of both anions and cations, minimum time required for the separation, and satisfactory detection sensitivity were obtained in a reasonable time. The method was successfully applied to the simultaneous determination of anions and cations in natural waters.

  4. Isotope Fractionation of chlorine in Aqueous System: One Study on Anion-Exchange Chromatography.

    Science.gov (United States)

    Musashi, M.; Oi, T.; Eggenkamp, H.; Van Cappellen, P.

    2001-05-01

    Stable chlorine isotopes such as 37Cl and 35Cl have been paid attention as useful tool identifying the source, and monitoring the transport process and natural fate of chlorinated organic pollutants in air and groundwater. However, it is not established yet whether any isotope effects accompany biodegradation or reductive dehalogenation of the pollutants (Clark and Fritz, 1997). Here we first present an experimental determination of isotope fractionation factor of chlorine in aqueous system by using anion-exchange chromatographic technique. Into the Cl-free anion exchange resin (Muromac, OH- form) packed in a 30 cm long pyrex glass column and controlled temperature at 25 oC, hydrochloric solution was fed with controlling the flow rate constant. Effluent from the column was recovered by an automatic fraction collector and prepared for Cl isotope analysis. The Cl isotope ratio (δ 37Cl vs. SMOC) was measured by IR-MS at the Utrecht University with precision of 0.06 per-mil. Magnitude of the factor obtained was 1.00035 at 25 oC. The result indicates that the lighter isotope (35Cl) was preferably fractionated into the resin phase, while the heavier one (37Cl) was enriched into the aqueous phase. This trend suggests that molecular structure of hydrolysis with Cl in aqueous phase may be more stable than that of Cl ionically bonding with the resin. This result may offer physico-chemical insights into behavior and fate of the pollutants.

  5. Behavior of copper (II )and uranium ( VI) in precipitation chromatography in the system anion exchange resin - hexacyanoferrate (II )

    International Nuclear Information System (INIS)

    In this work it is shown the efficiency of precipitation chromatography for separation and concentration of metallic elements by using a strong anionic-exchange resin saturated with hexacyanoferrate (II). Metallic cations, like Cu (II) and U (VI), are retained from highly diluted solutions and enriched into the resin, in the form of the correspondent insoluble hexacyanoferrate (II), precipitated inside the resin, which permitted the visual observation of a chromatographic zone on the top of the column. It will be discussed the conditions of sorption and elution of the cations uptake by the resin. This system permits the enrichment of the above mentioned cations onto the resin and offers the possibility of interesting separations as well. (author)

  6. Chemical separation of Mo and W from terrestrial and extraterrestrial samples via anion exchange chromatography.

    Science.gov (United States)

    Nagai, Yuichiro; Yokoyama, Tetsuya

    2014-05-20

    A new two-stage chemical separation method was established using an anion exchange resin, Eichrom 1 × 8, to separate Mo and W from four natural rock samples. First, the distribution coefficients of nine elements (Ti, Fe, Zn, Zr, Nb, Mo, Hf, Ta, and W) under various chemical conditions were determined using HCl, HNO3, and HF. On the basis of the obtained distribution coefficients, a new technique for the two-stage chemical separation of Mo and W, along with the group separation of Ti-Zr-Hf, was developed as follows: 0.4 M HCl-0.5 M HF (major elements), 9 M HCl-0.05 M HF (Ti-Zr-Hf), 9 M HCl-1 M HF (W), and 6 M HNO3-3 M HF (Mo). After the chemical procedure, Nb remaining in the W fraction was separated using 9 M HCl-3 M HF. On the other hand, Nb and Zn remaining in the Mo fraction were removed using 2 M HF and 6 M HCl-0.1 M HF. The performance of this technique was evaluated by separating these elements from two terrestrial and two extraterrestrial samples. The recovery yields for Mo, W, Zr, and Hf were nearly 100% for all of the examined samples. The total contents of the Zr, Hf, W, and Mo in the blanks used for the chemical separation procedure were 582, 9, 29, and 396 pg, respectively. Therefore, our new separation technique can be widely used in various fields of geochemistry, cosmochemistry, and environmental sciences and particularly for multi-isotope analysis of these elements from a single sample with significant internal isotope heterogeneities. PMID:24801276

  7. Identification of low-abundance proteins via fractionation of the urine proteome with weak anion exchange chromatography

    Directory of Open Access Journals (Sweden)

    Chen Jeff

    2011-04-01

    Full Text Available Abstract Background Low-abundance proteins are difficultly observed on the two-dimensional gel electrophoresis (2-DE maps of urine proteome, because they are usually obscured by high-abundance proteins such as albumin and immunoglobulin. In this study, a novel fractionation method was developed for enriching low-abundance proteins by removing high-abundance proteins and progressive elution with salts of various concentrations. Results Stepwise weak anion exchange (WAX chromatography, which applied DEAE-Sephacel resin with non-fixed volume elution, was used to fractionate urine proteome prior to performing 2-DE. Urine proteome was separated into four fractions by progressively eluting the column with 0 M, 50 mM, 100 mM, and 1 M NaCl solutions. Most of the heavy and light immunoglobulin chains appeared in the eluent. After the high-abundance proteins were removed, various low-abundance proteins were enriched and could be easily identified. The potential of this method for obtaining diversified fractionations was demonstrated by eluting the column separately with Na2SO4 and MgCl2 solutions. The 2-DE maps of the fractions eluted with these different salt solutions of identical ionic strength revealed markedly different stain patterns. Conclusion The present study demonstrated that this fractionation method could be applied for purposes of enriching low-abundance proteins and obtaining diversified fractionations of urine, and potentially other proteomes.

  8. Improvement of sugar analysis sensitivity using anion-exchange chromatography-electrospray ionization mass spectrometry with sheath liquid interface.

    Science.gov (United States)

    Xu, Xian-Bing; Liu, Ding-Bo; Guo, Xiao Ming; Yu, Shu-Juan; Yu, Pei

    2014-10-31

    A novel interface that enables high-performance anion-exchange chromatography (HPAEC) to be coupled with electrospray ionization (ESI) mass spectrometry (MS) is reported. A sheath liquid consisting of 50mM NH4Ac in isopropanol with 0.05% acetic acid, infused at a flow rate of 3μL/min at the tip of the electrospray probe, requires less ESI source cleaning and promotes efficient ionization of mono- and di-carbohydrates. The results suggest that use of a sheath liquid interface rather than a T-joint allows volatile ammonium salts to replace non-volatile metal salts as modifiers for improving sugar ESI signals. The efficient ionization of mono- and di-carbohydrates in the ESI source is affected by the sheath liquid properties such as buffer concentration and type of organic solvent. HPAEC-ESI-MS was used for the analysis of monocarbohydrates in pectins, particularly co-eluted sugars, and the performance was evaluated. Addition of a make-up solution through the sheath liquid interface proved to be an efficient tool for enhancing the intensities of sugars analyzed using HPAEC-ESI-MS. PMID:25246101

  9. Size exclusion and anion exchange high performance liquid chromatography for characterizing metals bound to marine dissolved organic matter

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Otero, Natalia; Bermejo-Barrera, Pilar [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela (Spain); Moreda-Pineiro, Antonio, E-mail: antonio.moreda@usc.es [Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n, 15782 Santiago de Compostela (Spain)

    2013-01-14

    Highlights: Black-Right-Pointing-Pointer Fractionation methods for assessing metals bound to marine DOM were developed. Black-Right-Pointing-Pointer SEC and AEC with UV detection and hyphenated with inductively coupled plasma-mass spectrometry were used. Black-Right-Pointing-Pointer SEC-UV showed marine DOM of molecular weights from 16 to 1 kDa. Black-Right-Pointing-Pointer Cobalt, manganese, strontium and zinc are bound to marine DOM. - Abstract: Size exclusion chromatography (SEC) followed by anion exchange chromatography (AEC) hyphenated with inductively coupled plasma-mass spectrometry (ICP-MS) was applied for fractionating metals bound to marine dissolved organic matter (DOM). Surface seawater samples (100 L) were subjected to tangential flow ultrafiltration (10,000 Da cut off) for isolating and pre-concentrating dissolved large molecules. The isolated fraction (retentate) consisted of 1 L, which was further freeze-dried and re-dissolved to 250 mL with ultrapure water. After HI Trap desalting of the re-dissolved retentate, SEC with UV detection showed marine DOM ranging from 6.5 kDa (lower than the permeable volume of the SEC column) to 16 kDa. A further characterization of this fraction by AEC with UV detection revealed the existence of four groups of macromolecules exhibiting retention times of 2.3, 2.8, 4.5 and 14.0 min. AEC hyphenated with ICP-MS showed the presence of strontium and zinc in the first AE fraction isolated from the SEC fraction; while manganese was found to be bound to the second AE fraction. Cobalt was found to be bound to molecules comprising the third AE fraction.

  10. Dextrin characterization by high-performance anion-exchange chromatography--pulsed amperometric detection and size-exclusion chromatography--multi-angle light scattering--refractive index detection.

    Science.gov (United States)

    White, D Richard; Hudson, Patricia; Adamson, Julie T

    2003-05-16

    Starch hydrolysis products, or dextrins, are widely used throughout the food industry for their functional properties. Dextrins are saccharide polymers linked primarily by alpha-(1 --> 4) D-glucose units and are prepared by partial hydrolysis of starch. Hydrolysis can be accomplished by the use of acid, enzymes, or by a combination of both. The hydrolysis products are typically characterized by the "dextrose equivalent" (DE), which refers to the total reducing power of all sugars present relative to glucose. While the DE gives the supplier and buyer a rough guide to the bulk properties of the material, the physiochemical properties of dextrins are dependent on the overall oligosaccharide profile. High-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection and size-exclusion chromatography (SEC) with multi-angle light-scattering and refractive index detection were used to characterize dextrins from commercial sources. HPAEC was used to acquire the oligosaccharide profile, and SEC to obtain an overall molar mass distribution. These methods in combination extended our understanding of the relationship between oligosaccharide profile, DE, and the hydrolysis process. Data from the two techniques enabled a method for estimating the DE that gave results in reasonable agreement with the accepted titration method. PMID:12830879

  11. Cleanup and analysis of sugar phosphates in biological extracts by using solid phase extraction and anion-exchange chromatography with pulsed amperometric detection

    DEFF Research Database (Denmark)

    Smith, Hans Peter; Cohen, A.; Buttler, T.;

    1998-01-01

    Saccharomyces cerevisiae obtained by using cold methanol as quenching agent and chloroform as extraction solvent. It was shown that pretreatment of the cell extract with SPE markedly improved the quality of the liquid chromatography analysis with recoveries of the sugar phosphates close to 100%. Furthermore......A cleanup method based on anion-exchange solid-phase extraction (SPE) was developed to render biological extracts suitable for the analysis of hexose phosphates with a modified anion-exchange chromatography method and pulsed amperometric detection. The method was applied to cell extracts of......, the method allowed for sample enrichment and the original extraction procedure could be simplified by implementing SPE early in the extraction protocol. (C) 1998 Academic Press....

  12. The development of sequential separation methods for the analysis of actinides in sediments and biological materials using anion-exchange resins and extraction chromatography

    International Nuclear Information System (INIS)

    New, quantitative methods for the determination of actinides have been developed for application to marine environmental samples (e.g., sediment and fish). The procedures include aggressive dissolution, separation by anion-exchange resin, separation and purification by extraction chromatography (e.g., TRU, TEVA and UTEVA resins) with measurement of the radionuclides by semiconductor alpha-spectrometry (SAS). Anion-exchange has proved to be a strong tool to treat large volume samples, and extraction chromatography shows an excellent selectivity and reduction of the amounts of acids. The results of the analysis of uranium, thorium, plutonium and americium isotopes by this method in marine samples (IAEA-384, -385 and -414) provided excellent agreement with the recommended values with good chemical recoveries. (author)

  13. A simplified method for levoglucosan quantification in wintertime atmospheric particulate matter by high performance anion-exchange chromatography coupled with pulsed amperometric detection

    OpenAIRE

    Piazzalunga, A.; P. Fermo; Bernardoni, V.; VECCHI, R; Valli, G.; M. Gregorio

    2010-01-01

    Levoglucosan, a tracer for the assessment of the biomass burning contribution to atmospheric particulate matter (PM) concentrations, was determined by means of high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD). In this work we propose a modification in the instrumental set-up aiming at an improvement in the detector response by adding NaOH after chromatographic separation to increase the pH. The comparison betwe...

  14. Determination of Amino Acids in Cell Culture and Fermentation Broth Media Using Anion-Exchange Chromatography with Integrated Pulsed Amperometric Detection

    OpenAIRE

    Hanko, Valoran P.; Heckenberg, Andrea; Rohrer, Jeffrey S.

    2004-01-01

    Anion-exchange chromatography with integrated pulsed amperometric detection (AE-IPAD) separates and directly detects amino acids, carbohydrates, alditols, and glycols in the same injection without pre- or post-column derivatization. These separations use a combination of NaOH and NaOH/sodium acetate eluents. We previously published the successful use of this technique, also known as AAA-Direct, to determine free amino acids in cell culture and fermentation broth media. We showed that retentio...

  15. Survey of inorganic arsenic in marine animals and marine certified reference materials by anion exchange high-performance liquid chromatography-inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Sloth, Jens Jørgen; Larsen, Erik Huusfeldt; Julshamn, Kåre

    2005-01-01

    A method for the determination of inorganic arsenic in seafood samples using high-performance liquid chromatography-inductively coupled plasma mass spectrometry is described. The principle of the method relied on microwave-assisted alkaline dissolution of the sample, which at the same time oxidized...... arsenite [As(Ill)] to arsenate [As(V)], whereby inorganic arsenic could be determined as the single species As(V). Anion exchange chromatography using isocratic elution with aqueous ammonium carbonate as the mobile phase was used for the separation of As(V) from other coextracted organoarsenic compounds...

  16. [Determination of fructooligosaccharides in milk powder using high performance anion-exchange chromatography coupled with pulsed amperometric detection].

    Science.gov (United States)

    Geng, Lijuan; Huang, Junrong; Feng, Feng; Jiang, Pingping; Chu, Xiaogang; Zhang, Feng; Ling, Yun

    2014-12-01

    Fructooligosaccharides (FOS) are usually added in milk powder as a kind of prebiotic. Thus, quantitative analysis of the FOS is very important for the quality control of milk powder. In this study, a simple method for the simultaneous determination of three FOS components with degrees of polymerization (DP) 3-5 in milk powder was developed by high performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). The samples were extracted with 50% (v/v) ethanol aqueous solution and defatted by an On Guard RP pretreatment column. The separation was performed on a CarboPac PA200 column by gradient elution using deionized water, 0. 2 mol/L NaOH solution and 0. 4 mol/L NaAc solution as the mobile phases. The flow rate was 0. 4 mL/min. The column temperature was 30 °C; and the injection volume was 25 µL. Good linear response was observed in the concentration range of 0.05-10 mg/L (r2 >0. 9993). The limits of quantification were 0. 02, 0. 005 and 0. 02 mg/L for 1-kestose, nystose and fructofuranosyl-nystose, respectively. The mean recoveries varied from 86. 0% to 114. 0% at three spiked levels of 0. 5, 1. 0 and 5. 0 mg/L. The short-chain fructooligosaccharides from inulooligosaccharides (IOS) were successfully separated by the developed HPAEC-PAD method. The method is simple, accurate, sensitive, and helpful for the quality control of milk powder. PMID:25902647

  17. Assessing gibberellins oxidase activity by anion exchange/hydrophobic polymer monolithic capillary liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Chen, Ming-Luan; Su, Xin; Xiong, Wei; Liu, Jiu-Feng; Wu, Yan; Feng, Yu-Qi; Yuan, Bi-Feng

    2013-01-01

    Bioactive gibberellins (GAs) play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography--mass spectrometry (cLC-MS) method for the sensitive assay of in-vitro recombinant or endogenous GA3-oxidase by analyzing the catalytic substrates and products of GA3-oxidase (GA1, GA4, GA9, GA20). An anion exchange/hydrophobic poly([2-(methacryloyloxy)ethyl]trimethylammonium-co-divinylbenzene-co-ethylene glycol dimethacrylate)(META-co-DVB-co-EDMA) monolithic column was successfully prepared for the separation of all target GAs. The limits of detection (LODs, Signal/Noise = 3) of GAs were in the range of 0.62-0.90 fmol. We determined the kinetic parameters (K m) of recombinant GA3-oxidase in Escherichia coli (E. coli) cell lysates, which is consistent with previous reports. Furthermore, by using isotope labeled substrates, we successfully evaluated the activity of endogenous GA3-oxidase that converts GA9 to GA4 in four types of plant samples, which is, to the best of our knowledge, the first report for the quantification of the activity of endogenous GA3-oxidase in plant. Taken together, the method developed here provides a good solution for the evaluation of endogenous GA3-oxidase activity in plant, which may promote the in-depth study of the growth regulation mechanism governed by GAs in plant physiology. PMID:23922762

  18. Assessing gibberellins oxidase activity by anion exchange/hydrophobic polymer monolithic capillary liquid chromatography-mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Ming-Luan Chen

    Full Text Available Bioactive gibberellins (GAs play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography--mass spectrometry (cLC-MS method for the sensitive assay of in-vitro recombinant or endogenous GA3-oxidase by analyzing the catalytic substrates and products of GA3-oxidase (GA1, GA4, GA9, GA20. An anion exchange/hydrophobic poly([2-(methacryloyloxyethyl]trimethylammonium-co-divinylbenzene-co-ethylene glycol dimethacrylate(META-co-DVB-co-EDMA monolithic column was successfully prepared for the separation of all target GAs. The limits of detection (LODs, Signal/Noise = 3 of GAs were in the range of 0.62-0.90 fmol. We determined the kinetic parameters (K m of recombinant GA3-oxidase in Escherichia coli (E. coli cell lysates, which is consistent with previous reports. Furthermore, by using isotope labeled substrates, we successfully evaluated the activity of endogenous GA3-oxidase that converts GA9 to GA4 in four types of plant samples, which is, to the best of our knowledge, the first report for the quantification of the activity of endogenous GA3-oxidase in plant. Taken together, the method developed here provides a good solution for the evaluation of endogenous GA3-oxidase activity in plant, which may promote the in-depth study of the growth regulation mechanism governed by GAs in plant physiology.

  19. Strong anion-exchange fast performance liquid chromatography as a versatile tool for preparation and purification of RNA produced by in vitro transcription.

    Science.gov (United States)

    Koubek, Jiri; Lin, Ku Feng; Chen, Yet Ran; Cheng, Richard Ping; Huang, Joseph Jen Tse

    2013-10-01

    Here we demonstrate the use of strong anion-exchange fast performance liquid chromatography (FPLC) as a simple, fast, and robust method for RNA production by in vitro transcription. With this technique, we have purified different transcription templates from unreacted reagents in large quantities. The same buffer system could be used to readily remove nuclease contamination from the overexpressed pyrophosphatase, the important reagent for in vitro transcription. In addition, the method can be used to monitor in vitro transcription reactions to enable facile optimization of reaction conditions, and we have compared the separation performance between strong and weak anion-exchange FPLC for various transcribed RNAs, including the Diels-Alder ribozyme, the hammerhead ribozyme tRNA, and 4.5S RNA. The functionality of the purified tRNA(Cys) has been confirmed by the aminoacylation assay. Only the purification by strong anion-exchange FPLC has led to the enrichment of the functional tRNA from run-off transcripts as revealed by both enzymatic and electrophoretic analysis. PMID:23929938

  20. Studies on thermal stability of type I and type II anion exchange resins used for separation of isotopes of boron by ion exchange chromatography

    International Nuclear Information System (INIS)

    Thermal stability of indigenously available type I and type II anion exchange resins were studied in chloride and hydroxyl forms. The results of the study indicated that the resins under study were thermally stable up to 50 deg C even when heated in an oven for 180 days and there was no appreciable loss in ion exchange capacity of the resins for boric acid. (author)

  1. Water quality monitoring system for determination of ionic nutrients by ion-exclusion chromatography with spectrophotometric detection on cationand anion-exchange resin columns using water eluent

    Institute of Scientific and Technical Information of China (English)

    Daisuke KOZAKI; Nobutakc NAKATANI; Masanobu MORI; Nobukazu NAKAGOSHI; Kazuhiko TANAKA

    2012-01-01

    A unified ion-exclusion chromatography(IEC)system for monitoring anionic and cationic nutrients like NH+4,NO-2,NO-3,phosphate ion,silicate ion and HCO-3 was developed and applied to several environmental waters.The IEC system consisted of four IEC methodologies,including the IEC with ultraviolet(UV)detection at 210 nm for determining NH-4 on anion-exchange separation column in OH form connected with anion-exchange UV-conversion column in I-form in tandem,the IEC with UV-detection at 210 nm for determining simultaneously NO-2 and NO-3 on cation-exchange separation column in H+ form,the IEC with UV-detection at 210 nm for determining HCO-3 on cation-exchange separation column in H+ form connected with anionexchange UV-conversion column in I-form in tandem,and the IEC with visible-detection based on molybdenum-blue reaction for determining simultaneously silicate and phosphate ions on cation-exchange separation column in H + form.These IEC systems were combined through three manually-driven 6-port column selection valves to select each separation column to determine selectively the ionic nutrients.Using this sequential water quality monitoring system,the analytical performances such as calibration linearity,reproducibility,detection limit and recovery were also tested under the optimized chromatographic conditions.This novel water quality monitoring system has been applied successfully for the determination of the ionic eutrophication components in sub-urban river waters.

  2. Modeling and simulation of anion-exchange membrane chromatography for purification of Sf9 insect cell-derived virus-like particles.

    Science.gov (United States)

    Ladd Effio, Christopher; Hahn, Tobias; Seiler, Julia; Oelmeier, Stefan A; Asen, Iris; Silberer, Christine; Villain, Louis; Hubbuch, Jürgen

    2016-01-15

    Recombinant protein-based virus-like particles (VLPs) are steadily gaining in importance as innovative vaccines against cancer and infectious diseases. Multiple VLPs are currently evaluated in clinical phases requiring a straightforward and rational process design. To date, there is no generic platform process available for the purification of VLPs. In order to accelerate and simplify VLP downstream processing, there is a demand for novel development approaches, technologies, and purification tools. Membrane adsorbers have been identified as promising stationary phases for the processing of bionanoparticles due to their large pore sizes. In this work, we present the potential of two strategies for designing VLP processes following the basic tenet of 'quality by design': High-throughput experimentation and process modeling of an anion-exchange membrane capture step. Automated membrane screenings allowed the identification of optimal VLP binding conditions yielding a dynamic binding capacity of 5.7 mg/mL for human B19 parvovirus-like particles derived from Spodoptera frugiperda Sf9 insect cells. A mechanistic approach was implemented for radial ion-exchange membrane chromatography using the lumped-rate model and stoichiometric displacement model for the in silico optimization of a VLP capture step. For the first time, process modeling enabled the in silico design of a selective, robust and scalable process with minimal experimental effort for a complex VLP feedstock. The optimized anion-exchange membrane chromatography process resulted in a protein purity of 81.5%, a DNA clearance of 99.2%, and a VLP recovery of 59%. PMID:26718185

  3. Determination of antisense phosphorothioate oligonucleotides and catabolites in biological fluids and tissue extracts using anion-exchange high-performance liquid chromatography and capillary gel electrophoresis.

    Science.gov (United States)

    Chen, S H; Qian, M; Brennan, J M; Gallo, J M

    1997-04-25

    Chemically modified phosphorothioate oligodeoxynucleotides (ODNs) have become critical tools for research in the fields of gene expression and experimental therapeutics. Bioanalytical assays were developed that utilized fast anion-exchange high-performance liquid chromatography (HPLC) and capillary gel electrophoresis (CGE) for the determination of 20-mer ODNs in biological fluids (plasma and urine) and tissues. A 20 mer ODN in the antisense orientation directed against DNA methyltransferase (denoted as MT-AS) was studied as the model ODN. The anion-exchange HPLC method employed a short column packed with non-porous polymer support and a ternary gradient elution with 2 M lithium bromide containing 30% formamide. Analysis of the MT-AS is accomplished within 5 min with a detection limit of approximately 3 ng on-column at 267 nm. For plasma and urine, samples were diluted with Nonidet P-40 in 0.9% NaCl and directly injected onto the column, resulting in 100% recovery. For tissue homogenates, a protein kinase K digestion and phenol-chloroform extraction were used, with an average recovery of about 50%. Since the HPLC assay cannot provide one-base separation, biological samples were also processed by an anion-exchange solid-phase extraction and a CGE method to characterize MT-AS and its catabolites of 15-20-mer, species most relevant to biological activity. One base separation, under an electric field of 400 V/cm at room temperature, was achieved for a mixture of 15-20-mer with about 50 pg injected. Assay validation studies revealed that the combined HPLC-CGE methods are accurate, reproducible and specific for the determination of MT-AS and its catabolites in biological fluids and tissue homogenates, and can be used for the pharmacokinetic characterization of MT-AS. PMID:9187382

  4. Pu Anion Exchange Process Intensification

    Energy Technology Data Exchange (ETDEWEB)

    Taylor-Pashow, K. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-08

    This project seeks to improve the efficiency of the plutonium anion-exchange process for purifying Pu through the development of alternate ion-exchange media. The objective of the project in FY15 was to develop and test a porous foam monolith material that could serve as a replacement for the current anion-exchange resin, Reillex® HPQ, used at the Savannah River Site (SRS) for purifying Pu. The new material provides advantages in efficiency over the current resin by the elimination of diffusive mass transport through large granular resin beads. By replacing the large resin beads with a porous foam there is much more efficient contact between the Pu solution and the anion-exchange sites present on the material. Several samples of a polystyrene based foam grafted with poly(4-vinylpyridine) were prepared and the Pu sorption was tested in batch contact tests.

  5. Assay for inorganic pyrophosphate in chondrocyte culture using anion-exchange high-performance liquid chromatography and radioactive orthophosphate labeling

    International Nuclear Information System (INIS)

    A method is described for determination of inorganic pyrophosphate (PPi) in cell culture medium and in rabbit articular chondrocytes grown in the presence of radioactive orthophosphate (32Pi). Intra- and extracellular 32PPi formed was measured using high-performance liquid chromatographic (HPLC) separation of the PPi from orthophosphate (Pi) and other phosphate-containing compounds. The chromatographic separation on a weak anion-exchange column is based on the extent to which various phosphate compounds form complexes with Mg2+ at low pH and the rate at which such formation occurs. These complexes are eluted more readily than the uncomplexed compounds. Best results were obtained using a simultaneous gradient of Mg2+ ions and ionic strength. In this case separation of small amounts of PPi from a large excess of Pi was possible without prior removal of Pi or extraction of the PPi fraction. The assay is also useful for measurement of inorganic pyrophosphatase activity. The sensitivity of the assay depends on the specific activity of the added 32Pi and on the culture conditions, but is comparable with the most sensitive of the enzymatic assays. Sample preparation, particularly deproteinization, proved to be of importance. The losses of PPi which occur during procedures of this sort due to hydrolysis and coprecipitation were quantitated

  6. Quantification of 1,5-anhydro-D-glucitol in urine by automated borate complex anion-exchange chromatography with an immobilized enzyme reactor.

    Science.gov (United States)

    Tanabe, T; Tajima, S; Suzuki, T; Okawa, E; Machida, R; Ichimura, S; Yabuuchi, M

    1997-04-25

    HPLC using a borate form of a strongly anion-exchange resin column and an immobilized enzyme reactor for colorimetric detection was used to quantify urinary 1,5-anhydro-D-glucitol. Urine samples were introduced into the system every 7 min without any pretreatment, and after separation of interfering substances in the column, 1,5-anhydro-D-glucitol was successively detected. Quantitative determination of urinary 1,5-anhydro-D-glucitol was possible within the 1.2-300 micromol/l range. The coefficient of variance was less than 3% and the correlation between results obtained with our system (y) and those obtained by gas chromatography-mass spectrometry (x) was y=0.983x-1.287 micromol/l (n=42, r=0.998). PMID:9187379

  7. Selenium speciation analysis in a sediment using strong anion exchange and reversed phase chromatography coupled with inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ochsenkuehn-Petropoulou, M.; Michalke, B.; Kavouras, D.; Schramel, P

    2003-02-22

    An analytical procedure for selenium speciation of analysis of selenourea (SeU), selenoethionine (SeE), selenomethionine (SeM), Se(VI), Se(IV), dimethylselenide (dMeSe) and dimethyldiselenide (dMedSe) was developed, based on two complementary liquid chromatography (LC) techniques coupled with inductively coupled plasma-mass spectrometry (ICP-MS). Specifically, strong anion exchange (SAX) chromatography coupled with ICP-MS was used for the separation and quantification of all the earlier mentioned Se compounds, except for the two methyl selenides, which could be separated and determined by reversed phase chromatography coupled with ICP-MS. This procedure was applied to a soil sample from the warm springs area of Thermopyles (Greece). For leaching the Se species from the soil sample, four extraction methods, using water at ambient temperature, hot water, methanol and 0.5 M HCl, were tested for their efficiency of extracting the different Se species. The speciation results obtained by the LC-ICP-MS methods were compared with those obtained by voltammetric techniques. The determination of total selenium in the sample was achieved by graphite furnace atomic absorption spectrometry, as well as by ICP-atomic emission spectrometry, after suitable digestion of the sediment sample.

  8. Simultaneous determination of inorganic and organic anions by ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yang Soon; Joe, Ki Soo; Han, Sun Ho; Park, Soon Dal; Choi, Kwang Soon

    1999-06-01

    Four methods were investigated for the simultaneous determination of several inorganic and organic anions in aqueous solution by ion chromatography. The first is two columns coupled system. The second is the gradient elution system with an anion exchange column. The third is the system with a mixed-mode stationary phase. The fourth is the system with an anion exchange column and the eluant of low conductivity without ion suppressor. The advantages and disadvantages of individual systems were discussed. The suitable methods were proposed for the application to the samples of the nuclear power industry and the environment. (author)

  9. Simple, selective, and rapid quantification of 1-deoxynojirimycin in mulberry leaf products by high-performance anion-exchange chromatography with pulsed amperometric detection.

    Science.gov (United States)

    Yoshihashi, Tadashi; Do, Huong Thi Thu; Tungtrakul, Patcharee; Boonbumrung, Sumitra; Yamaki, Kohji

    2010-04-01

    1-Deoxynojirimycin (DNJ) occurs in mulberry and other plants and is a highly potent glycosidase inhibitor reported to suppress blood glucose levels, thus preventing diabetes. Derivatization is required for quantification of DNJ upon use of spectral detection methods. Because of this difficulty, the DNJ contents of mulberry-based food products are rarely stated, even if DNJ is their active component. A simple, selective, and rapid method of high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) to quantify DNJ in mulberry-based food products was developed. Stability testing of DNJ under heat treatment was also performed. A water extract of mulberry tea sample was subjected to HPAEC-PAD in a CarboPac MA1 column with a sodium hydroxide gradient. DNJ was clearly separated at a retention time of 7.26 min without interference and was selectively detected in the water extract. The detection limit was 5 ng. Heat stability studies suggested that DNJ was heat stable. HPAEC-PAD was not subject to interference, was highly selective for DNJ, and was superior to other high-performance liquid chromatography (HPLC) techniques in terms of sample preparation, resolution, and sensitivity. The method allowed simple, selective, and rapid analysis of DNJ in food matrices and might be useful for development of mulberry-based food products. Heat treatment could be an option for sterilizing mulberry-based products. PMID:20492274

  10. Rapid and sensitive quantification of levoglucosan in aerosols by high-performance anion-exchange chromatography with positive electrospray ionization mass spectrometry (HPAEC-positive ESI-MS)

    Science.gov (United States)

    Asakawa, Daichi; Furuichi, Yuko; Yamamoto, Atsushi; Oku, Yuichiro; Funasaka, Kunihiro

    2015-12-01

    A convenient quantification method for underivatized levoglucosan, which is a tracer for biomass burning influenced particulate matter (PM), has been established using high-performance anion-exchange chromatography (HPAEC) coupled to positive electrospray ionization mass spectrometry ((+)ESI-MS). Levoglucosan was chromatographically separated from its isomers (mannosan and galactosan) and detected selectively with positive ESI-MS. Limits of detection and quantification for this method were 0.40 and 1.3 ng mL-1, respectively. A comparison of simultaneous measurements by this method and conventional derivatization gas chromatography/mass spectrometry showed a good linearity with a slope of 1.008 and a determination coefficient of 0.9932. The developed method was applied to ambient suspended particulate matter hourly collected by continuous particulate monitors at 10 stations. The hourly concentration of levoglucosan during August 9-11, 2011, was 1.7-918 ng m-3 and its distribution indicated the transportation of biomass burning aerosols of a forest fire. This is the first report of horizontal distribution of the hourly levoglucosan concentration in Japan.

  11. Analytical Method for Sugar Profile in Pet Food and Animal Feeds by High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection.

    Science.gov (United States)

    Ellingson, David J; Anderson, Phillip; Berg, Daniel P

    2016-03-01

    There is a need for a standardized, accurate, rugged, and consistent method to measure for sugars in pet foods and animal feeds. Many traditional standard sugar methods exist for other matrixes, but when applied in collaborative studies there was poor agreement and sources of error identified with those standard methods. The advancement in technology over the years has given us the ability to improve on these standard methods of analysis. A method is described here that addresses these common issues and was subjected to a single-laboratory validation to assess performance on a wide variety of pet foods and animal feeds. Of key importance to the method performance is the sample preparation before extraction, type of extraction solvent, postextraction cleanup, and, finally, optimized chromatography using high-performance anion exchange chromatography with pulsed amperometric detection. The results obtained from the validation demonstrate how typical issues seen with these matrixes can influence performance of sugar analysis. The results also demonstrate that this method is fit-for-purpose and can meet the challenges of sugar analysis in pet food and animal feeds to lay the foundation for a standardized method of analysis. PMID:26952902

  12. Separation of human milk oligosaccharides using high-performance anion-exchange chromatography with pulsed amperometric detection

    DEFF Research Database (Denmark)

    Lie, Aleksander; Pedersen, Lars Haastrup

    ) with pulsed amperometric detection (PAD) is an analysis method highly suited for carbohydrates. HPAE with alkaline eluents results in retention of neutral carbohydrates depending on the number of charged groups in the molecule, pH and concentration of competing anions, while PAD has sensitivity for...

  13. Rapid simultaneous analysis of oxyhalides and inorganic anions in aqueous media by ion exchange chromatography with indirect UV detection

    Directory of Open Access Journals (Sweden)

    Mohammadine El Haddad

    2015-01-01

    Best separations have also occured between(Cl-/ClO3- and(Br-/BrO3- with good a resolution. Detections limits (S/N = 3 ofBrO3-,ClO3-andNO3- were 2 and 5 ppm for inorganic anions Cl−, Br− andSO42-. The method had a good linearity (r2 > 0.995 and high precision (relative standard deviation <4%. The main reason for the detector choice was that UV detectors are widespread in educational and low level equipment laboratories. Indirect photometric detection is an attractive and inexpensive approach and the system is versatile.

  14. Assessing Gibberellins Oxidase Activity by Anion Exchange/Hydrophobic Polymer Monolithic Capillary Liquid Chromatography-Mass Spectrometry

    OpenAIRE

    Ming-Luan Chen; Xin Su; Wei Xiong; Jiu-Feng Liu; Yan Wu; Yu-Qi Feng; Bi-Feng Yuan

    2013-01-01

    Bioactive gibberellins (GAs) play a key regulatory role in plant growth and development. In the biosynthesis of GAs, GA3-oxidase catalyzes the final step to produce bioactive GAs. Thus, the evaluation of GA3-oxidase activity is critical for elucidating the regulation mechanism of plant growth controlled by GAs. However, assessing catalytic activity of endogenous GA3-oxidase remains challenging. In the current study, we developed a capillary liquid chromatography – mass spectrometry (cLC-MS) m...

  15. Radioimmunoassay of a new angiotensin-converting enzyme inhibitor (perindopril) in human plasma and urine: Advantages of coupling anion-exchange column chromatography with radioimmunoassay

    Energy Technology Data Exchange (ETDEWEB)

    Doucet, L.; De Veyrac, B.; Delaage, M.; Cailla, H.; Bernheim, C.; Devissaguet, M. (Immunotech S. A. Case 915, Marseille (France))

    1990-08-01

    Perindopril (P) is a prodrug whose active metabolite perindoprilat (PT) is an antihypertensive agent which acts by inhibition of angiotensin-converting enzyme (ACE). Anti-PT antiserum was produced in a rabbit immunized against PT that was covalently linked to bovine serum albumin. The radioligand is an iodinated ({sup 125}I) derivative of PT-glycyltyrosinamide. Both the drug (PT) and the prodrug (P) are assayed in the same sample; PT is assayed as is and P is assayed after quantitative alkaline hydrolysis into PT. Certain data obtained from such assays suggest the occurrence in plasma and urine of a third immunoreactive component. A chromatographic fractionation of samples allowed us to isolate a new immunoreactive metabolite which was further identified as a glucuronide of PT (PT-G). Therefore, the whole assay was carried out as follows: biological samples were fractionated by stepwise chromatography on a anion-exchange resin (the first fraction contained P, the second contained PT, and the third contained PT-G); and RIA was performed on fractions 2 and 3 as is, and on fraction 1 after alkaline hydrolysis. Performances and assessments of this method are presented together with an example of a pharmacokinetic profile.

  16. Determination of mycophenolic acid in mest products using mixed mode reversed phase-anion exchange clean-up and liquid chromatography-high-resolution mass spectrometry

    DEFF Research Database (Denmark)

    Sørensen, Louise Marie; Nielsen, Kristian Fog; Jacobsen, Thomas;

    2008-01-01

    A method for determination of mycophenolic acid (MPA) in dry-cured ham, fermented sausage and liver pate is described. MPA was extracted from meat with bicarbonate-acetonitrile, further cleaned-up by mixed mode reversed phase-anion exchange and detected using a LC-MS system with electrospray...

  17. A simple and rapid method for measuring α-D-phosphohexomutases activity by using anion-exchange chromatography coupled with an electrochemical detector.

    Science.gov (United States)

    Jia, Xiaochen; Kang, Jian; Yin, Heng

    2016-01-01

    The interconversion of hexose-6-phosphate and hexose-1-phosphate can be directly analyzed by high-performance anion-exchange chromatography coupled with an electrochemical detector (HPAEC-PAD). Thus, this method can be used to measure the activities of N-acetylglucosamine-phosphate mutase (AGM), glucosamine-phosphate mutase (GlmM) and phosphoglucomutase (PGM), which are the members of α-D-phosphohexomutases superfamily. The detection limits were extremely low as 2.747 pmol, 1.365 pmol, 0.512 pmol, 0.415 pmol, 1.486 pmol and 0.868 pmol for N-acetylglucosamine-1-phosphate (GlcNAc-1-P), N-acetylglucosamine-6-phosphate (GlcNAc-6-P), glucosamine-1-phosphate (GlcN-1-P), glucosamine-6-phosphate (GlcN-6-P), glucose-1-phosphate (Glc-1-P) and glucose-6-phosphate (Glc-6-P), respectively. By employing HPAEC-PAD, activities of AtAGM (AGM from Arabidopsis thaliana) on these six phosphohexoses can be detected. The Km of AtAGM on Glc-1-P determined by HPAEC-PAD was 679.18 ± 156.40 µM, which is comparable with the Km of 707.09 ± 170.36 µM detected by traditional coupled assay. Moreover, the activity of MtGlmM (GlmM from Mycobacterium tuberculosis) on GlcN-6-P tested by HPAEC-PAD was 7493.40 ± 309.12 nmol∕min ⋅ mg, which is much higher than 288.97 ± 35.28 nmol∕min ⋅ mg obtained by the traditional coupled assay. Accordingly, HPAEC-PAD is a more rapid and simple method than the traditional coupled assays given its high specificity and sensitivity, and will certainly bring convenience to further research of α-D-phosphohexomutases. PMID:26788420

  18. Simultaneous separation and quantitative determination of monosaccharides, uronic acids, and aldonic acids by high performance anion-exchange chromatography coupled with pulsed amperometric detection in corn stover prehydrolysates

    Directory of Open Access Journals (Sweden)

    Xing Wang

    2012-11-01

    Full Text Available A method for simultaneous separation and quantitative determination of arabinose, galactose, glucose, xylose, xylonic acid, gluconic acid, galacturonic acid, and glucuronic acid was developed by using high performance anion-exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD. The separation was performed on a CarboPacTM PA-10 column (250 mm × 2 mm with a various gradient elution of NaOH-NaOAc solution as the mobile phase. The calibration curves showed good linearity (R2 ≥ 0.9993 for the monosaccharides, uronic acids, and aldonic acids in the range of 0.1 to 12.5 mg/L. The detection limits (LODs and the quantification limits (LOQs were 4.91 to 18.75 μg/L and 16.36 to 62.50 μg/L, respectively. Relative standard deviations (RSDs of the retention times and peak areas for the seven consecutive determinations of an unknown amount of mixture were 0.15% to 0.44% and 0.22% to 2.31%, respectively. The established method was used to separate and determine four monosaccharides, two uronic acids, and two aldonic acids in the prehydrolysate from dilute acid steam-exploded corn stover within 21 min. The spiked recoveries of monosaccharides, uronic acids, and aldonic acids ranged from 91.25% to 108.81%, with RSDs (n=3 of 0.04% ~ 6.07%. This method was applied to evaluate the quantitative variation of sugar and sugar acid content in biomass prehydrolysates.

  19. Determination of nitric oxide metabolites, nitrate and nitrite, in Anopheles culicifacies mosquito midgut and haemolymph by anion exchange high-performance liquid chromatography: plausible mechanism of refractoriness

    Directory of Open Access Journals (Sweden)

    Adak Tridibesh

    2008-04-01

    Full Text Available Abstract Background The diverse physiological and pathological role of nitric oxide in innate immune defenses against many intra and extracellular pathogens, have led to the development of various methods for determining nitric oxide (NO synthesis. NO metabolites, nitrite (NO2- and nitrate (NO3- are produced by the action of an inducible Anopheles culicifacies NO synthase (AcNOS in mosquito mid-guts and may be central to anti-parasitic arsenal of these mosquitoes. Method While exploring a plausible mechanism of refractoriness based on nitric oxide synthase physiology among the sibling species of An. culicifacies, a sensitive, specific and cost effective high performance liquid chromatography (HPLC method was developed, which is not influenced by the presence of biogenic amines, for the determination of NO2- and NO3- from mosquito mid-guts and haemolymph. Results This method is based on extraction, efficiency, assay reproducibility and contaminant minimization. It entails de-proteinization by centrifugal ultra filtration through ultracel 3 K filter and analysis by high performance anion exchange liquid chromatography (Sphereclone, 5 μ SAX column with UV detection at 214 nm. The lower detection limit of the assay procedure is 50 pmoles in all midgut and haemolymph samples. Retention times for NO2- and NO3- in standards and in mid-gut samples were 3.42 and 4.53 min. respectively. Assay linearity for standards ranged between 50 nM and 1 mM. Recoveries of NO2- and NO3- from spiked samples (1–100 μM and from the extracted standards (1–100 μM were calculated to be 100%. Intra-assay and inter assay variations and relative standard deviations (RSDs for NO2- and NO3- in spiked and un-spiked midgut samples were 5.7% or less. Increased levels NO2- and NO3- in midguts and haemolymph of An. culicifacies sibling species B in comparison to species A reflect towards a mechanism of refractoriness based on AcNOS physiology. Conclusion HPLC is a sensitive

  20. Rapid isolation of plutonium in environmental solid samples using sequential injection anion exchange chromatography followed by detection with inductively coupled plasma mass spectrometry.

    Science.gov (United States)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per; Miró, Manuel

    2011-01-31

    This paper reports an automated analytical method for rapid determination of plutonium isotopes ((239)Pu and (240)Pu) in environmental solid extracts. Anion exchange chromatographic columns were incorporated in a sequential injection (SI) system to undertake the automated separation of plutonium from matrix and interfering elements. The analytical results most distinctly demonstrated that the crosslinkage of the anion exchanger is a key parameter controlling the separation efficiency. AG 1-×4 type resin was selected as the most suitable sorbent material for analyte separation. Investigation of column size effect upon the separation efficiency revealed that small-sized (2 mL) columns sufficed to handle up to 50 g of environmental soil samples. Under the optimum conditions, chemical yields of plutonium exceeded 90% and the decontamination factors for uranium, thorium and lead ranged from 10(3) to 10(4). The determination of plutonium isotopes in three standard/certified reference materials (IAEA-375 soil, IAEA-135 sediment and NIST-4359 seaweed) and two reference samples (Irish Sea sediment and Danish soil) revealed a good agreement with reference/certified values. The SI column-separation method is straightforward and less labor intensive as compared with batch-wise anion exchange chromatographic procedures. Besides, the automated method features low consumption of ion-exchanger and reagents for column washing and elution, with the consequent decrease in the generation of acidic waste, thus bearing green chemical credentials. PMID:21168558

  1. Rapid isolation of plutonium in environmental solid samples using sequential injection anion exchange chromatography followed by detection with inductively coupled plasma mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Qiao Jixin, E-mail: jixin.qiao@risoe.d [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Hou Xiaolin; Roos, Per [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Miro, Manuel [Department of Chemistry, Faculty of Sciences, University of the Balearic Islands, Carretera de Valldemossa km. 7.5, E-07122 Palma de Mallorca, Illes Balears (Spain)

    2011-01-31

    This paper reports an automated analytical method for rapid determination of plutonium isotopes ({sup 239}Pu and {sup 240}Pu) in environmental solid extracts. Anion exchange chromatographic columns were incorporated in a sequential injection (SI) system to undertake the automated separation of plutonium from matrix and interfering elements. The analytical results most distinctly demonstrated that the crosslinkage of the anion exchanger is a key parameter controlling the separation efficiency. AG 1-x4 type resin was selected as the most suitable sorbent material for analyte separation. Investigation of column size effect upon the separation efficiency revealed that small-sized (2 mL) columns sufficed to handle up to 50 g of environmental soil samples. Under the optimum conditions, chemical yields of plutonium exceeded 90% and the decontamination factors for uranium, thorium and lead ranged from 10{sup 3} to 10{sup 4}. The determination of plutonium isotopes in three standard/certified reference materials (IAEA-375 soil, IAEA-135 sediment and NIST-4359 seaweed) and two reference samples (Irish Sea sediment and Danish soil) revealed a good agreement with reference/certified values. The SI column-separation method is straightforward and less labor intensive as compared with batch-wise anion exchange chromatographic procedures. Besides, the automated method features low consumption of ion-exchanger and reagents for column washing and elution, with the consequent decrease in the generation of acidic waste, thus bearing green chemical credentials.

  2. Rapid isolation of plutonium in environmental solid samples using sequential injection anion exchange chromatography followed by detection with inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    This paper reports an automated analytical method for rapid determination of plutonium isotopes (239Pu and 240Pu) in environmental solid extracts. Anion exchange chromatographic columns were incorporated in a sequential injection (SI) system to undertake the automated separation of plutonium from matrix and interfering elements. The analytical results most distinctly demonstrated that the crosslinkage of the anion exchanger is a key parameter controlling the separation efficiency. AG 1-x4 type resin was selected as the most suitable sorbent material for analyte separation. Investigation of column size effect upon the separation efficiency revealed that small-sized (2 mL) columns sufficed to handle up to 50 g of environmental soil samples. Under the optimum conditions, chemical yields of plutonium exceeded 90% and the decontamination factors for uranium, thorium and lead ranged from 103 to 104. The determination of plutonium isotopes in three standard/certified reference materials (IAEA-375 soil, IAEA-135 sediment and NIST-4359 seaweed) and two reference samples (Irish Sea sediment and Danish soil) revealed a good agreement with reference/certified values. The SI column-separation method is straightforward and less labor intensive as compared with batch-wise anion exchange chromatographic procedures. Besides, the automated method features low consumption of ion-exchanger and reagents for column washing and elution, with the consequent decrease in the generation of acidic waste, thus bearing green chemical credentials.

  3. Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates

    Science.gov (United States)

    Rounds, M. A.; Nielsen, S. S.; Mitchell, C. A. (Principal Investigator)

    1993-01-01

    The use of gradient anion-exchange HPLC, with a simple post-column detection system, is described for the separation of myo-inositol phosphates, including "phytic acid" (myo-inositol hexaphosphate). Hexa-, penta-, tetra-, tri- and diphosphate members of this homologous series are clearly resolved within 30 min. This method should facilitate analysis and quantitation of "phytic acid" and other inositol phosphates in plant, food, and soil samples.

  4. Anion exchange chromatography for the determination of 5-methyl-2'-deoxycytidine: application to cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines.

    Science.gov (United States)

    Iglesias, Tamara; Espina, Marta; Montes-Bayón, María; Sierra, Luisa María; Blanco-González, Elisa

    2015-03-01

    Epigenetic alterations are increasingly implicated in the initiation and progression of cancer. Genome-wide (global) hypomethylation seems to occur in early neoplasia and is a feature of genomic DNA derived from solid tumour tissues like ovarian cancer. Thus, analytical methods that provide sensitive and quantitative information about cytosine methylation in DNA are currently required. In this work, we compare two different anion-exchange columns for the separation of methylated cytosine from the other DNA nucleotides: a silica-based (Tracer Extrasil SAX) column and a polystyrene/divinyl benzene-based (Mono-Q™) column. Under the optimised conditions, linearity range, precision and detection limits of the developed high-performance liquid chromatography (HPLC) method were evaluated and compared using conventional ultraviolet (UV) absorbance detection at 270 nm. Good separation of the five target nucleotides, including 5-methyl-2'-deoxycytidine monophosphate (5mdCMP) and 2'-deoxycytidine monophosphate (dCMP) was achieved on the Mono-Q™ column with a gradient elution of ammonium acetate buffer (1 M, pH 6.9) at a flow rate of 1 mL min(-1). The coupling of this column to inductively coupled plasma mass spectrometry (ICP-MS) permitted also phosphorous ((31)P) specific detection of the nucleotides. Both detection systems offered adequate analytical performance characteristics, with detection limits of 30 and 40 μg L(-1) for 5mdCMP by HPLC-UV and HPLC-ICP-MS, respectively. However, the latter method allowed the determination of the global DNA methylation level (%) without the need for external calibration. Different genomic DNA samples were analysed including calf thymus DNA and DNA from two human cancer cell lines (adenocarcinoma epithelial A549 and ovarian carcinoma A2780) using the proposed strategy. In the line A2780, the cisplatin-sensitive and cisplatin-resistant variants were analysed, finding no significant differences in the methylation percentage after

  5. An enzymatic method for the determination of fructans in foods and food products - Comparison of the results by high performance anion exchange chromatography with pulsed amperemetric detection

    DEFF Research Database (Denmark)

    Andersen, Rikke; Sørensen, A.

    1999-01-01

    measurement of the released sugars enzymatically. Sucrose is hydrolysed by alpha-glucosidase instead of beta-fructosidase, which is normally used. In addition, sucrose is measured in the form of D-fructose instead of the typical D-glucose form, and the fructanase used to hydrolyse the fructans has fewer side...... effects than the fructanase reported as normally used. The method is tested on ten standard substances and five fructan products, and nine foods and food products are also analysed. The enzymatic measurement of the released sugars is confirmed by measurements done by high performance anion exchange...

  6. Improvement of separation efficiencies of anion-exchange chromatography using monolithic silica capillary columns modified with polyacrylates and polymethacrylates containing tertiary amino or quaternary ammonium groups.

    Science.gov (United States)

    Watanabe, Yuta; Ikegami, Tohru; Horie, Kanta; Hara, Takeshi; Jaafar, Jafariah; Tanaka, Nobuo

    2009-10-30

    Anion-exchange (AEX) columns were prepared by on-column polymerization of acrylates and methacrylates containing tertiary amino or quaternary ammonium groups on monolithic silica in a fused silica capillary modified with anchor groups. The columns provided a plate height (H) of less than 10 microm at optimum linear velocity (u) with keeping their high permeability (K=9-12 x 10(-14) m2). Among seven kinds of AEX columns, a monolithic silica column modified with poly(2-hydroxy-3-(4-methylpiperazin-1-yl)propyl methacrylates) (HMPMA) showed larger retentions and better selectivities for nucleotides and inorganic anions than the others. The HMPMA column of 410 mm length produced 42,000-55,000 theoretical plates (N) at a linear velocity of 0.97 mm/s with a backpressure of 3.8 MPa. The same column could be employed for a fast separation of inorganic anions in 1.8 min at a linear velocity of 5.3 mm/s with a backpressure of 20 MPa. In terms of van Deemter plot and separation impedance, the HMPMA column showed higher performance than a conventional particle-packed AEX column. The HMPMA column showed good recovery of a protein, trypsin inhibitor, and it was applied to the separation of proteins and tryptic digest of bovine serum albumin (BSA) in a gradient elution, to provide better separation compared to a conventional particle-packed AEX column. PMID:19683243

  7. Capacity gradient anion chromatography with a borate complex as eluent.

    Science.gov (United States)

    Yamamoto, A; Inoue, Y; Kodama, S; Matsunaga, A

    1999-07-30

    Complex formation between borate compounds and vicinal diols is well recognized. Generally, in a chemically bonded anion-exchange resin, many hydroxyl groups are introduced on the surface of the resin in order to make the resin hydrophilic. The borate as an eluting reagent also reacts to these hydroxyl groups, and this complex formation decreases the apparent ion-exchange capacity of the column by being dissociated to the anion depending on the eluent pH. In the present work a method is described for the simultaneous determination of anions based on the capacity gradient for suppressed ion chromatography. A Tosoh IC-Anion-PW column and dihydroxyphenylborane-mannitol eluent system were used. To maintain baseline stability, it was helpful to keep the borate concentration constant during a gradient of 16 to 0 mM mannitol as a modifier to prevent the complex formation with the hydroxyl on the resin. The chemical composition of the eluents and gradient profiles are discussed and the application to the analysis of the condensed phosphates with widely varying retention times as food additives in a cheese sample is presented. PMID:10457467

  8. Selective determination of ammonium ions by high-speed ion-exclusion chromatography on a weakly basic anion-exchange resin column.

    Science.gov (United States)

    Mori, Masanobu; Tanaka, Kazuhiko; Helaleh, Murad I H; Xu, Qun; Ikedo, Mikaru; Ogura, Yutaka; Sato, Shinji; Hu, Wenzhi; Hasebe, Kiyoshi

    2003-05-16

    This paper describes an ion-exclusion chromatographic system for the rapid and selective determination of ammonium ion. The optimized ion-exclusion chromatographic system was established with a polymethacrylate-based weakly basic anion-exchange resin column (TSKgel DEAE-5PW) as the separation column, an aqueous solution containing 0.05 mM tetramethylammonium hydroxide (pH 9.10) as eluent with conductimetric detection for the analyte determination. Under the optimum chromatographic conditions, ammonium ion was determined within 2.3 min with a detection limit (S/N=3) better than 0.125 microM. Ammonium ion in rain and river waters was precisely determined using this ion-exclusion chromatographic system. PMID:12830892

  9. Rapid isolation of plutonium in environmental solid samples using sequential injection anion exchange chromatography followed by detection with inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Qiao, Jixin; Hou, Xiaolin; Roos, Per;

    2011-01-01

    This paper reports an automated analytical method for rapid determination of plutonium isotopes (239Pu and 240Pu) in environmental solid extracts. Anion exchange chromatographic columns were incorporated in a sequential injection (SI) system to undertake the automated separation of plutonium from...... size effect upon the separation efficiency revealed that small-sized (2 mL) columns sufficed to handle up to 50 g of environmental soil samples. Under the optimum conditions, chemical yields of plutonium exceeded 90% and the decontamination factors for uranium, thorium and lead ranged from 103 to 104....... The determination of plutonium isotopes in three standard/certified reference materials (IAEA-375 soil, IAEA-135 sediment and NIST-4359 seaweed) and two reference samples (Irish Sea sediment and Danish soil) revealed a good agreement with reference/certified values. The SI column-separation method...

  10. Rapid determination of vitellogenin in fish plasma by anion exchange high performance liquid chromatography using postcolumn fluorescence derivatization with o-phthalaldehyde.

    Science.gov (United States)

    Wu, Cuiqin; Yuan, Dongxing; Liu, Baomin

    2006-12-01

    An analytical method involving anion exchange high performance liquid chromatographic determination of vitellogenin (Vtg) in fish plasma after postcolumn fluorescence derivatization with o-phthalaldehyde (OPA) was developed. The retention time of Vtg was about 11 min. The reagent variables for derivatization were optimized. The fluorophore was excited at 335 nm and detected at 435 nm. A calibration curve was established ranging from 0.13 to 11.28 microg. The determination limit of Vtg was found to be as low as 0.13 microg. The spiked recovery was 93.6% and interassay variability was less than 4%. The method developed was used to determine Vtg in fish plasma obtained from red sea bream (Pagrosomus major), black porgy (Sparus macrocephalus) and skew band grunt (Hapalogenys nitens), without complicated sample pretreatment. The results confirmed that the method showed advantages of being simple, rapid, reproducible and sensitive. PMID:17159322

  11. Determination of Cr(VI) in welding fumes by anion-exchange fast protein liquid chromatography with electrothermal atomic absorption spectrometric detection.

    Science.gov (United States)

    Milacic, Radmila; Scancar, Janez; Tusek, Janez

    2002-02-01

    The applicability of an anion-exchange fast protein liquid chromatographic-electrothermal atomic absorption spectrometric procedure (FPLC-ETAAS) was investigated for the determination of Cr(VI) in welding fumes after alkaline extraction of aerosols loaded on filters. Gas tungsten arc welding (GTAW) of stainless steel was applied. Samples of welding fumes were collected during regular welding on polycarbonate membrane filters of 8 microm and 0.4 microm pore size (inhalable and respirable aerosols). Alkaline extraction (2% NaOH-3% Na2CO3) of filters in a heated ultrasonic bath was applied to leach Cr from the airborne particulate matter. 0.5 cm3 of sample extract was then injected onto an anion-exchange FPLC column. Tris-HCl buffer (0.005 mol dm(-3), pH 8.0) and the same buffer with NaCl (0.5 mol dm(-3)) were employed in gradient elution (15 min, flow rate 1 cm3 min(-1)). The separated Cr species were determined "off line" by ETAAS in 0.5 cm3 fractions. Cr(VI) was reproducibly and quantitatively eluted from 12.0 to 13.0 min with a maximum peak at 12.5 min. Good repeatability of measurement (+/-3.0%) of alkaline extracts was obtained for Cr(VI). The LOD (3s) was found to be 0.035 microg m(-3) Cr(VI), when 2 m3 of aerosols were collected on the filter. Validation of the procedure was performed by spiking alkaline extracts and by the analysis of standard reference material CRM 545, Cr(VI) in welding dust loaded on a filter. The technique was successfully applied for the determination of Cr(VI) in welding fumes. PMID:11939630

  12. Short-column anion-exchange chromatography for soil and peat humic substances profiling by step-wise gradient of high pH aqueous sodium ethylenediaminetetraacetate.

    Science.gov (United States)

    Hutta, Milan; Ráczová, Janka; Góra, Róbert; Pessl, Juraj

    2015-08-21

    Novel anion-exchange liquid chromatographic method with step gradient of aqueous EDTA(4-) based mobile phase elution has been developed to profile available Slovak soil humic substances and alkaline extracts of various soils. The method utilize short glass column (30mm×3mm) filled in with hydrolytically stable particles (60μm diameter) Separon HEMA-BIO 1000 having (diethylamino)ethyl functional groups. Step gradient was programmed by mixing mobile phase composed of aqueous solution of sodium EDTA (pH 12.0; 5mmolL(-1)) and mobile phase constituted of aqueous solution of sodium EDTA (pH 12.0, 500mmolL(-1)). The FLD of HSs was set to excitation wavelength 480nm and emission wavelength 530nm (λem). Separation mechanism was studied by use of selected aromatic acids related to humic acids with the aid of UV spectrophotometric detection at 280nm. The proposed method benefits from high ionic strength (I=5molL(-1)) of the end mobile phase buffer and provides high recovery of humic acids (98%). Accurate and reproducible profiling of studied humic substances, alkaline extracts of various types of soils enables straightforward characterization and differentiation of HSs in arable and forest soils. Selected model aromatic acids were used for separation mechanism elucidation. PMID:26143606

  13. Online determination of levoglucosan in ambient aerosols with Particle-into-Liquid Sampler – High-Performance Anion-Exchange Chromatography – Mass Spectrometry (PILS–HPAEC–MS

    Directory of Open Access Journals (Sweden)

    K. Saarnio

    2013-06-01

    Full Text Available Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a Particle-into-Liquid Sampler (PILS to a high-performance anion-exchange chromatograph (HPAEC with the detection by a mass spectrometer (MS is presented for the online analysis of levoglucosan in ambient particles. The PILS–HPAEC–MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC–MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS. As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m−3 during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m−3 seemed to originate from biomass burning in Eastern Europe, likely in Estonia, that was transported to Helsinki.

  14. Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler – high-performance anion-exchange chromatography – mass spectrometry (PILS–HPAEC–MS

    Directory of Open Access Journals (Sweden)

    K. Saarnio

    2013-10-01

    Full Text Available Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PILS to a high-performance anion-exchange chromatograph (HPAEC with the detection by a mass spectrometer (MS is presented for the online analysis of levoglucosan in ambient particles. The PILS–HPAEC–MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC–MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS. As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m−3 during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m−3 seemed to originate from biomass burning in the Baltic countries, likely in Estonia, that was transported to Helsinki.

  15. Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler - high-performance anion-exchange chromatography - mass spectrometry (PILS-HPAEC-MS)

    Science.gov (United States)

    Saarnio, K.; Teinilä, K.; Saarikoski, S.; Carbone, S.; Gilardoni, S.; Timonen, H.; Aurela, M.; Hillamo, R.

    2013-10-01

    Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PILS) to a high-performance anion-exchange chromatograph (HPAEC) with the detection by a mass spectrometer (MS) is presented for the online analysis of levoglucosan in ambient particles. The PILS-HPAEC-MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC-MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m-3) during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m-3) seemed to originate from biomass burning in the Baltic countries, likely in Estonia, that was transported to Helsinki.

  16. Separation of bivalent anti-T cell immunotoxin from Pichia pastoris glycoproteins by borate anion exchange.

    Science.gov (United States)

    Woo, Jung Hee; Neville, David M

    2003-08-01

    A major problem encountered in the large-scale purification of the bivalent anti-T cell immunotoxin, A-dmDT390-bisFv(G4S), from Pichia pastoris supernatants was the presence of host glycoproteins exhibiting similar charge, size, and hydrophobicity characteristics. We overcame this problem by employing borate anion exchange chromatography. The borate anion has an affinity for carbohydrates and imparts negative charges to these structures. We found that at a concentration of sodium borate between 50 and 100 mM, the nonglycosylated immunotoxin did not bind to Poros 50 HQ anion exchanger resin, but glycoproteins, including aggregates related to the immunotoxin, did. By using this property of the immunotoxin in the presence of sodium borate, we successfully developed a 3-step purification procedure: (i) Butyl-650M hydrophobic interaction chromatography, (ii) Poros 50 HQ anion exchange chromatography in the presence of borate, and (iii) HiTrap Q anion exchange chromatography. The final preparation exhibited a purity of greater than 98% and a yield of greater than 50% from the supernatant. Previously, boronic acid resins have been used to separate glycoproteins from proteins. However, combining borate anion with conventional anion exchange resins accomplishes the separation of the immunotoxin from glycoproteins and eliminates the need to evaluate nonstandard resins with respect to good manufacturing practice guidelines. PMID:12951782

  17. Removal of transmissible spongiform encephalopathy prion from large volumes of cell culture media supplemented with fetal bovine serum by using hollow fiber anion-exchange membrane chromatography.

    Directory of Open Access Journals (Sweden)

    Ming Li Chou

    Full Text Available Cases of variant Creutzfeldt-Jakob disease in people who had consumed contaminated meat products from cattle with bovine spongiform encephalopathy emphasize the need for measures aimed at preventing the transmission of the pathogenic prion protein (PrPSc from materials derived from cattle. Highly stringent scrutiny is required for fetal bovine serum (FBS, a growth-medium supplement used in the production of parenteral vaccines and therapeutic recombinant proteins and in the ex vivo expansion of stem cells for transplantation. One such approach is the implementation of manufacturing steps dedicated to removing PrPSc from materials containing FBS. We evaluated the use of the QyuSpeed D (QSD adsorbent hollow-fiber anion-exchange chromatographic column (Asahi Kasei Medical, Tokyo, Japan for the removal of PrPSc from cell culture media supplemented with FBS. We first established that QSD filtration had no adverse effect on the chemical composition of various types of culture media supplemented with 10% FBS or the growth and viability characteristics of human embryonic kidney (HEK293 cells, baby hamster kidney (BHK-21 cells, African green monkey kidney (Vero cells, and Chinese hamster ovary (CHO-k1 cells propagated in the various culture-medium filtrates. We used a 0.6-mL QSD column for removing PrPSc from up to 1000 mL of Dulbecco's modified Eagle's medium containing 10% FBS previously spiked with the 263K strain of hamster-adapted scrapie. The Western blot analysis, validated alongside an infectivity assay, revealed that the level of PrPSc in the initial 200mL flow-through was reduced by 2.5 to > 3 log10, compared with that of the starting material. These results indicate that QSD filtration removes PrPSc from cell culture media containing 10% FBS, and demonstrate the ease with which QSD filtration can be implemented in at industrial-scale to improve the safety of vaccines, therapeutic recombinant proteins, and ex vivo expanded stem cells produced

  18. Speciation analysis of calcium, iron, and zinc in casein phosphopeptide fractions from toddler milk-based formula by anion exchange and reversed-phase high-performance liquid chromatography-mass spectrometry/flame atomic-absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Miquel, Esther; Alegria, Amparo; Barbera, Reyes; Farre, Rosaura [University of Valencia, Nutrition and Food Chemistry, Faculty of Pharmacy, Burjassot, Valencia (Spain)

    2005-03-01

    Casein phosphopeptides (CPP) are phosphorylated casein-derived peptides that can be released by in-vitro or in-vivo enzymatic hydrolysis of {alpha}{sub s1}-casein, {alpha}{sub s2}-casein, and {beta}-casein (CN). Many of these peptides contain a highly polar acidic sequence of three phosphoseryl groups followed by two glutamic acid residues. These domains are binding sites for minerals such as calcium, iron, and zinc and play an important role in mineral bioavailability. The aim of this study was speciation analysis of calcium, iron, and zinc in CPP fractions from the soluble fraction of a toddler milk-based formula. Methods for CPP separation by anion-exchange high-performance liquid chromatography (AE-HPLC) were combined with CPP identification by reversed-phase high performance liquid chromatography-electrospray ionization mass spectrometry and determination of the calcium, iron, zinc, and phosphorus content of the fractions obtained by AE-HPLC. Calcium and phosphorus were detected in all the analyzed AE-HPLC fractions. Calcium and zinc could be bound to CPP derived from {alpha}{sub s1}-CN and {alpha}{sub s2}-CN in fraction 3. Iron could be bound to CPP in fraction 4 in which {beta}-CN(15-34)4P was present with the cluster sequence S(P)S(P)S(P)EE. The results obtained prove the different distribution of calcium, iron, and zinc in heterogeneous CPP fractions. (orig.)

  19. Cleanup and analysis of sugar phosphates in biological extracts by using solid phase extraction and anion-exchange chromatography with pulsed amperometric detection

    DEFF Research Database (Denmark)

    Smith, Hans Peter; Cohen, A.; Buttler, T.; Nielsen, Jens Bredal; Olsson, Lisbeth

    1998-01-01

    Saccharomyces cerevisiae obtained by using cold methanol as quenching agent and chloroform as extraction solvent. It was shown that pretreatment of the cell extract with SPE markedly improved the quality of the liquid chromatography analysis with recoveries of the sugar phosphates close to 100%. Furthermore...

  20. Simultaneous determination of inorganic anions, calcium and magnesium by suppressed ion chromatography.

    Science.gov (United States)

    García-Fernández, Ruben; García-Alonso, J Ignacio; Sanz-Medel, Alfredo

    2004-04-01

    Suppressed conductimetric detection ion chromatography (IC) was investigated for the separation and detection of common inorganic anions, calcium and magnesium by anion-exchange chromatography using a sodium carbonate-EDTA mobile phase. The formation of anionic Ca2+ -EDTA and Mg2+ -EDTA complexes allowed its separation from other inorganic anions opening the way for their simultaneous determination in a single chromatographic run. The effect of the pH, carbonate and EDTA concentrations in the eluent and the previous addition of EDTA to the samples has been studied. The optimised experimental conditions were applied to the determination of Ca2+ and Mg2+ in mineral waters with results in agreement with alternative ICP-MS methodologies. PMID:15072297

  1. Advancements in Anion Exchange Membrane Cations

    Energy Technology Data Exchange (ETDEWEB)

    Sturgeon, Matthew R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Long, Hai [National Renewable Energy Lab. (NREL), Golden, CO (United States); Park, Andrew M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Pivovar, Bryan S. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-15

    Anion-exchange membrane fuel cells (AME-FCs) are of increasingly popular interest as they enable the use of non-Pt fuel cell catalysts, the primary cost limitation of proton exchange membrane fuel cells. Benzyltrimethyl ammonium (BTMA) is the standard cation that has historically been utilized as the hydroxide conductor in AEMs. Herein we approach AEMs from two directions. First and foremost we study the stability of several different cations in a hydroxide solution at elevated temperatures. We specifically targeted BTMA and methoxy and nitro substituted BTMA. We've also studied the effects of adding an akyl spacer units between the ammonium cation and the phenyl group. In the second approach we use computational studies to predict stable ammonium cations, which are then synthesized and tested for stability. Our unique method to study cation stability in caustic conditions at elevated temperatures utilizes Teflon Parr reactors suitable for use under various temperatures and cation concentrations. NMR analysis was used to determine remaining cation concentrations at specific time points with GCMS analysis verifying product distribution. We then compare the experimental results with calculated modeling stabilities. Our studies show that the electron donating methoxy groups slightly increase stability (compared to that of BTMA), while the electron withdrawing nitro groups greatly decrease stability in base. These results give insight into possible linking strategies to be employed when tethering a BTMA like ammonium cation to a polymeric backbone; thus synthesizing an anion exchange membrane.

  2. A new method for separation and determination of Cr(III) and Cr(VI) in water samples by high-performance liquid chromatography based on anion exchange stationary phase of ionic liquid modified silica.

    Science.gov (United States)

    Sadeghi, Susan; Moghaddam, Ali Zeraatkar

    2015-12-01

    In this work, N-methylimidazolium-chloride ionic liquid functionalized silica was prepared and used as an anion-exchange stationary phase for separation of chromium species by high-performance liquid chromatography (HPLC) with UV detection at 200 nm. The Cr(VI) as HCr2O7(-) and chelated Cr(III) with potassium hydrogen phthalate (PHP) as Cr(PHP)2 (-) was retained on the prepared column and separated using a mobile phase composed of 5% methanol in 25 mM phosphate buffer at pH 6.5. Several variables affecting the chelation/separation steps were modeled by response surface methodology (RSM) using Box-Behnken (BBD) design. The significance of the independent variables and their interactions were tested by the analysis of variances (ANOVA) with 95% confidence limit. Under the optimized conditions, the Cr(III) and Cr(VI) anionic species were well separated with a single peak for each Cr species at retention times of 2.3 and 4.3 min, respectively. The relationship between the peak area and concentration was linear in the range of 0.025-30 for Cr(III) and 0.5-20 mg L(-1) for Cr(VI) with detection limits of 0.010 and 0.210 mg L(-1) for Cr(III) and Cr(VI), respectively. The proposed method was validated by simultaneous separation and determination of the Cr species in tap and underground water samples without impose to any pretreatment. PMID:26526699

  3. An enzymatic method for the determination of fructans in foods and food products - Comparison of the results by high performance anion exchange chromatography with pulsed amperemetric detection

    DEFF Research Database (Denmark)

    Andersen, Rikke; Sørensen, A.

    1999-01-01

    We report a new and non-equipment demanding method of measuring the content of fructans as well as the contents of free glucose, free fructose and sucrose in foods and food products enzymatically. This method comprises hydrolysis of fructans into D-glucose and D-fructose enzymatically and...... measurement of the released sugars enzymatically. Sucrose is hydrolysed by alpha-glucosidase instead of beta-fructosidase, which is normally used. In addition, sucrose is measured in the form of D-fructose instead of the typical D-glucose form, and the fructanase used to hydrolyse the fructans has fewer side...... chromatography with pulsed amperemetric detection....

  4. Efficiency of pretreatment of aqueous samples using a macroporous strong anion-exchange resin on the determination of nerve gas hydrolysis products by gas chromatography-mass spectrometry after tert.-butyldimethylsilylation.

    Science.gov (United States)

    Kataoka, M; Tsuge, K; Seto, Y

    2000-09-01

    A pretreatment procedure, using a macroporous strong anion-exchange resin (MSA) has been established for the determination of nerve gas hydrolysis products by gas chromatography-mass spectrometry (GC-MS) after tert.-butyldimethylsilyl (TBDMS) derivatization. Aqueous solutions of methylphosphonic acid (MPA) and three alkyl methylphosphonic acids (AMPAs) (ethyl, isopropyl and pinacolyl methylphosphonic acid), were retained on the MSA column, and then quantitatively eluted with 0.1 M hydrochloric acid. The neutralized column eluate was dried, and MPA and AMPAs were derivatized with N-methyl-N-(tert.-butyldimethylsilyl)-trifluoroacetamide and analyzed by GC-MS. The column eluate was also analyzed in order to determine the exact hydrolysis product levels by capillary electrophoresis using borate and benzoate buffer (pH 6). The MSA pretreatment was examined for the clean-up of aqueous extracts of three types of soils and an aqueous solution containing 10% sucrose, which is regarded as model for a typical soft drink, after spiking with MPA and AMPAs. MPA and AMPAs were quantitatively recovered in the MSA eluate fraction from those samples, except for MPA from volcanic acid and alluvial soils. The yields of TBDMS derivatives were remarkably improved, compared with for which no pretreatment was used and also for those in which a strong cation-exchange resin was used. The achieved detection limits of MPA and AMPAs ranged from 0.12 to 0.18 microg/g of soil (S/N=3). The established MSA method was applied to the pretreatment of spiked sea water, two types of beverages, Pepsi Cola and canned coffee. Although the yields of TBDMS derivatives of MPA and AMPAs in sea water (in a range between 44 and 96%) and AMPAs in Pepsi Cola (in a range between 58 and 92%) were rather high, those for MPA in the Pepsi Cola (27%) and those for MPA and AMPAs in the canned coffee (in a range between 5 and 17%) were low. PMID:11043790

  5. Separation of coagulation factor Ⅷ with high activity using gigaporous anion exchange chromatography%超大孔离子交换制备色谱分离纯化高活性凝血因子Ⅷ

    Institute of Scientific and Technical Information of China (English)

    康丽梅; 张焱; 罗坚; 李由; 周月芳; 余蓉; 苏志国

    2012-01-01

    建立了一条从人血浆中分离高活性凝血因子Ⅷ(FⅧ)的纯化工艺.基于FⅧ和介质孔径的尺度比及其对蛋白质活性影响的分析,设计了以超大孔离子交换制备色谱为核心步骤的新型分离纯化工艺.分别进行超大孔离子交换色谱与传统离子交换色谱的条件优化,并对优化工艺所得产品进行了活性检测(底物显色法)和纯度检测(高效凝胶过滤和凝胶电泳).结果表明,超大孔介质结构不但可以有效地保护蛋白质大分子结构,而且能够大幅度地提高制备色谱的传质速率,从而得到具有高凝血活性的FⅧ产品.FⅧ在超大孔制备色谱过程中的回收率(85%)比传统离子交换制备色谱高4~5倍,产品比活高达154 IU/mg.此外,还研究了超大孔介质的再生程序,采用5个柱体积的1mol/L NaOH低流速清洗色谱柱,保证了色谱工艺的稳定性.本纯化工艺步骤简单,重现性好,易于放大生产.%A purification process to obtain coagulation factor Vffl (FVI) with high activity from human plasma was established. Based on the analysis of the size ratio between FVi and matrix porous medium and its effect on the protein activity, a novel purification process designed was superporous ion exchange chromatography (IEC). The operating conditions of gigaporous and traditional anion exchange chromatography were optimized separately. The chromogenic substrate , gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis ( SDS-PAGE) were used to monitor the bioactivity and purity of the chromatographic products. The results showed that the superporous medium could not only protect structure of macro-protein but also enhance its mass transfer, finally giving FVI product with high activity. The yield of FVM in superporous chromatography was about five times of commercially agarose chromatography and the specific activity was up to 154 IU/mg protein. Furthermore, we studied the regeneration process of

  6. Ionic Block Copolymers for Anion Exchange Membranes

    Science.gov (United States)

    Tsai, Tsung-Han; Herbst, Dan; Giffin, Guinevere A.; di Noto, Vito; Witten, Tom; Coughlin, E. Bryan

    2013-03-01

    Anion exchange membrane (AEM) fuel cells have regained interest because it allows the use of non-noble metal catalysts. Until now, most of the studies on AEM were based on random polyelectrolytes. In this work, Poly(vinylbenzyltrimethylammonium bromide)-b- (methylbutylene) ([PVBTMA][Br]-b-PMB) was studied by SAXS, TEM and dielectric spectroscopy to understand the fundamental structure-conductivity relationship of ion transport mechanisms within well-ordered block copolymers. The ionic conductivity and the formation of order structure were dependent on the casting solvent. Higher ion exchange capacity (IEC) of the membranes showed higher conductivity at as IEC values below 1.8mmol/g, as above this, the ionic conductivity decreases due to more water uptake leading to dilution of charge density. The humidity dependence of morphology exhibited the shifting of d-spacing to higher value and the alteration in higher characteristic peak of SAXS plot as the humidity increase from the dry to wet state. This phenomenon can be further explained by a newly developed polymer brush theory. Three ionic conduction pathways with different conduction mechanism within the membranes can be confirmed by broadband electric spectroscopy. US Army MURI (W911NF1010520)

  7. Heat exchanger scale deposits analysis: application of ion chromatography

    International Nuclear Information System (INIS)

    Concentration level of leachable sulphate ions in the scale samples can be used as reliable indicators in analysis of failed heat exchanger tubes at Desalination Division, BARC. Determination of sulphate in non standard/rare samples like scale deposits need method development and method validation. Screening of scale deposit using X-ray fluorescence (EDXRF) was carried out to know the matrix and the suitable pretreatment procedure to be adopted before ion chromatography analysis. EDXRF studies showed that the sample contains calcium, iron, nickel, copper, silicon, as major elements and titanium, potassium as minor elements. The present study was carried out to develop a simple, rapid and accurate analytical methodology for the determination of sulphate in the above matrix. Scale sample was sonicated and supernatant was treated with H-guard cartridge to remove interfering metal ions. The quantitative determination of different anions was accomplished by anion exchange chromatography with conductometric detection in suppressed mode. A Dionex AS11-HC anion analytical column (4 mm X 250 mm) connected in series with a Dionex AG11-HC guard column (4 mm X 20 mm) was used for separation of anions. The mobile phase was a solution of 35 mM NaOH with a flow rate of 1.0 mL min-1. The column temperature was 30℃ and suppressor current was 112 mA. The optimum resolution and elution time for different anions were found under these conditions. The limit of detection for different anions was in the range 0.3-3 μg g-1 and the relative standard deviation was < 6% for the overall method

  8. Determination of inorganic anions in papermaking waters by ion chromatography

    Directory of Open Access Journals (Sweden)

    DARJA ŽARKOVIĆ

    2009-03-01

    Full Text Available A suppressed ion chromatography (IC method for the determination of inorganic anions in process water from paperboard production was developed and validated. Common inorganic anions (Cl-, NO3-, PO43- and SO42- were detected in fresh and process water samples collected from a paperboard production system at 16 characteristic points. It was shown that the use of an IonPac®-AS14 column under isocratic conditions with Na2CO3/NaHCO3 as the eluent and a suppression device proved to be a reliable analytical solution for the separation of the inorganic anions present in papermaking waters. This IC method is quite satisfactory concerning selectivity and sensitivity, and enables the determination of several inorganic anions over a wide concentration range. According to the obtained results, the total amount of analyzed inorganic anions was below 0.1 g/L, i.e., below the critical value which may trigger operational problems in paper production.

  9. Adsorption of U(VI) from HCl solutions on anion exchange resins

    International Nuclear Information System (INIS)

    Full text: The adsorption capacity of different commercial exchange resins, such as: Amberlite-RA 900 Cl; Amberjet 4400 Cl; Dowex 1-X8; Dowex-Marathon and CEPU-5M (synthesized specially for uranium isotope exchange), for uranyl chlorocomplexes in HCl solutions was determined. The measurements were performed at different temperatures and HCl solution concentrations using two contact methods for solution-resin system, namely through chromatography on column and batch operation. For anion exchange resins as Amberlite-IRA 900 Cl, Dowex 1-X8 and Dowex-Marathon, the uranium adsorption capacities increased with HCl concentrations and contact temperatures. The same behaviour was observed for anion exchange strong basic resin CEPU-5M, synthesized specially for uranium isotope exchange. Uranyl chlorocomplex molecule adsorbed on resin is [UO2Cl3]-, as determined by batch operation from uranium adsorption capacities of Dowex-Marathon. (author)

  10. Matrix elimination ion chromatography for determination of trace levels of anions in high purity lithium carbonate

    International Nuclear Information System (INIS)

    Lithium carbonate is used as a precursor in the synthesis of lithium-based ceramic, Li2TiO3, which is being considered as a promising solid breeder material in the tritium breeding blanket of thermonuclear fusion reactors . The presence of unwanted impurities in the precursor material can alter the ceramic properties of lithium titanate. Therefore a simple, rapid and accurate method for the determination of anionic impurities in high purity lithium carbonate has been developed. The quantitative determination of various anionic impurities (fluoride, chloride and sulphate) simultaneously was carried out by anion exchange chromatography with suppressed conductometric detection. The large concentration of carbonate anion in the solution poses a challenge in the determination of other anions present at trace level. Therefore the matrix elimination was accomplished by adopting a sample pretreatment for the removal of large excess of carbonate from the sample matrix. Onguard H-cartridges were found most suitable for this purpose. The H-guard cartridge has a packing of high capacity strong acid cation exchange resin in the H form. During the pretreatment procedure, the lithium ion in the sample exchange with H+ of the resin while the carbonate is converted to carbonic acid with the help of H+ ions. The Onguard H-cartridges could be successfully used to remove the interfering carbonate quantitatively from the salt solution provided that the concentration of carbonate is well below the total capacity of the packing material of the cartridges. The developed method was validated for its accuracy and precision. The limit of detection for various anions was in the range 0.02-0.4 μg g-1 and the relative standard deviation was 3-5 % for the overall method

  11. Use of type-II strong base anion exchange resins for ion exchange chromatographic separation of isotopes of boron

    International Nuclear Information System (INIS)

    The optimum conditions for the regeneration of strong base anion exchange resins of type-I and type-II were determined for cost - effective separation of isotopes of boron by ion exchange chromatography. The possibility of using unspent alkali content of the effluent was also exploited. Removal of carbonate impurity from rayon grade caustic lye (used as regenerant after dilution) and recycling of Ba(OH)2 was studied to avoid waste disposal problems. The determination of (i) ion exchange capacity of Duolite-162 resin for hydroxyl - chloride and hydroxyl - borate exchanges, (ii) isotopic exchange separation factor by batch method and (iii) effect of concentration of boric acid (in presence and absence of mannitol) on isotopic exchange separation factor to test the suitability of the type-II resin for this process are discussed. (author)

  12. Anion exchange purification of plasmid DNA using expanded bed adsorption.

    Science.gov (United States)

    Ferreira, G N; Cabral, J M; Prazeres, D M

    2000-01-01

    Recent developments in gene therapy with non-viral vectors and DNA vaccination have increased the demand for large amounts of pharmaceutical-grade plasmid DNA. The high viscosity of process streams is of major concern in the purification of plasmids, since it can cause high back pressures in column operations, thus limiting the throughput. In order to avoid these high back pressures, expanded bed anion exchange chromatography was evaluated as an alternative to fixed bed chromatography. A Streamline 25 column filled with 100 ml of Streamline QXL media, was equilibrated with 0.5 M NaCl in TE (10 mM Tris, 1 mM EDTA, pH = 8.0) buffer at an upward flow of 300 cmh-1, E. coli lysates (obtained from up to 3 liters of fermentation broth) were injected in the column. After washing out the unbound material, the media was allowed to sediment and the plasmid was eluted with 1 M NaCl in TE buffer at a downward flow of 120 cmh-1. Purification factors of 36 +/- 1 fold, 26 +/- 0.4 plasmid purity, and close to 100% yields were obtained when less than one settled column volume of plasmid feed was injected. However, both recovery yield and purity abruptly decreased when larger amounts were processed-values of 35 +/- 2 and 5 +/- 0.7 were obtained for the recovery yield and purity, respectively, when 250 ml of feedstock were processed. In these cases, gel clogging and expansion collapse were observed. The processing of larger volumes, thus larger plasmid quantities, was only possible by performing an isopropanol precipitation step prior to the chromatographic step. This step led to an enhancement of the purification step. PMID:10840595

  13. Rejuvenation processes applied to 'poisoned' anion exchangers in uranium processing

    International Nuclear Information System (INIS)

    The removal of 'poisons' from anion exchangers in uranium processing of Canadian radioactive ores is commonly called rejuvenation or regeneration. The cost of the ion exchange recovery of uranium is adversely affected by a decrease in the capacity and efficiency of the anion exchangers, due to their being 'poisoned' by silica, elemental sulphur, molybdenum and tetrathionates. These 'poisons' have a high affinity for the anion exchangers, are adsorbed in preference to the uranyl complex, and do not desorb with the reagents used normally in the uranyl desorption phase. The frequency of rejuvenation and the reagents required for rejuvenation are determined by the severity of the 'poisoning' accumulated by the exchanger in contact with the uranium leach liquor. Caustic soda (NaOH) at approximately equal to 18 cents/lb is commonly used to remove uranium anion exchangers of tetrathionate ((S406)/-/-) 'poisons'. A potential saving in operating cost would be of consequence if other reagents, e.g. sodium carbonate (Na2CO3) at approximately equal to 3.6 cents/lb or calcium hydroxide (Ca(OH)2) at approximately equal to 1.9 cents/lb, were effective in removing (S406)/-/-) from a 'poisoned' exchanger. A rejuvenation process for a test program was adopted after a perusal of the literature

  14. Inorganic anion exchangers for the treatment of radioactive wastes

    International Nuclear Information System (INIS)

    Inorganic anion exchangers are evaluated for Tc, I and S isotope removal from aqueous nuclear waste streams. Chemical, thermal, and radiation stabilities were examined. Selected exchangers were examined in detail for their selectivities, kinetics and mechanism of the sorption process (especially in NO3-, OH- and BO3- environments). Cement encapsulation and leaching experiments were made on the exchangers showing most promise for 'radwaste' treatment. (author)

  15. Selection of anion exchange resins for boron thermal regeneration systems

    International Nuclear Information System (INIS)

    Boron concentration changes in the reactor coolant are effected using a new development called the boron thermal regeneration system (BTRS). Thermal regeneration refers to the use of ion-exchange resins in either retaining or releasing borate ions as a function of temperature. For the BTRS the equilibrium capacity of commercial and special anion exchange resins was investigated for the degree of cross-linking of anion resins. The equilibrium capacity increases with decreased temperature and depends strongly on the degree of cross-linking having the maximum point at about 7% of DVB. The temperature coefficient of equilibrium capacity of boric acid is also a function of the concentration of external solution and of the cross-linking having a maximum point of around 7% of DVB. Other basic characteristics of anion exchange resin were also investigated. (author)

  16. Mechanism of boric acid sorption on strongly basic anion exchangers

    International Nuclear Information System (INIS)

    The sorption was studied of boric acid at different temperatures and initial solution concentrations on the strongly basic anion exchange resin DIAION SA10A. The pH value of the ion exchange resin phase was determined using acidobasic indicators. The results of measurement, mathematically and graphically processed show that the increased sorption capacity of strongly basic anion exchange resins resulting from the increased concentration of the boric acid sorption solution is due to the presence of the polyborate forms (B3O3(OH)4- and B3O3(OH)52-) in the ion exchange phase. Increasing the temperature results in boric acid release from the ion exchange resin as a result of the transformation of sorbed polyborate forms to the simpler (B(OH)4-) forms. (Ha)

  17. Separation of B-10 with weakly basic anion exchange resin

    International Nuclear Information System (INIS)

    In the study of B-10 isotope separation with weakly basic anion exchanger, the sorption isotherms of boric acid on WA-21 weak-base anion exchange resin and the sorption band shapes as well as its migration velocities in a four-inch diameter ion exchange column, were studied. The isotherms show S-shapes with gentle slope at both low concentration and high concentration regions. In the band migration study, it has been found that these S-shaped isotherms affected the velocities of the peak maximum as the band migrated along the column. The velocities could be calculated with the simple solute movement equation. These results suggest that sorption of molecular species, rather than ion exchange of the counterions is the main process that occurs inside the pores of a weak-base ion exchange resin which is in contact with a very weak electrolytic solution, such as that of boric acid. (author)

  18. Void exclusion of antibodies by grafted-ligand porous particle anion exchangers.

    Science.gov (United States)

    Nian, Rui; Chuah, Cindy; Lee, Jeremy; Gan, Hui Theng; Latiff, Sarah Maria Abdul; Lee, Wan Yee; Vagenende, Vincent; Yang, Yuan-Sheng; Gagnon, Pete

    2013-03-22

    We describe a new variant of anion exchange chromatography in columns packed with porous particles that embody charged low-density polymer zones supported by a higher density polymer skeleton. IgG defies the norms of anion exchange and is excluded to the void volume at pH 3-10 and 0-4M NaCl. Void exclusion also occurs with Fab, F(ab')2, and IgM. Host cell protein contaminants mostly follow the usual norms of anion exchange and bind more strongly with increasing pH and decreasing conductivity. Sample buffer composition has no impact on partitioning so long as applied sample volume does not exceed the interparticle void volume of the column. Void-excluded antibody elutes in equilibration buffer. This seemingly conflicted collection of behaviors is reconciled by a variable size exclusion function mediated through the low-density polymer zones, the charge properties of the antibody species, and the pH and conductivity of the equilibration buffer. Current-generation porous particle anion exchangers that employ grafting techniques to achieve high charge density mediate void exclusion to varying degrees, with the best-suited achieving complete exclusion, and others as little as 65%. Perfusive and non-grafted particle-based exchangers mediate as little as 50% exclusion. Monoliths mediate no exclusion, due to their lack of an interparticle void volume. On qualified exchangers, the technique supports greater than 99% reduction of host proteins, DNA, and endotoxin. Virus is reduced more than 99.9%, and aggregates are reduced to less than 0.05%. The method supports better process control than other anion exchange formats because pH excursions in conjunction with changes in salt concentration do not occur until after the antibody has eluted from the column. PMID:23422893

  19. A lanthanide complex for metal encapsulations and anion exchanges.

    Science.gov (United States)

    Sun, Yan-Qiong; Wan, Fang; Li, Xin-Xiong; Lin, Jian; Wu, Tao; Zheng, Shou-Tian; Bu, Xianhui

    2016-08-01

    A cationic lanthanide metalloligand with 3 dangling carboxylate groups on its periphery co-assembles with nitrate into a porous thermochromic solid responsive to both external cations and anions, owing to the presence of exchangeable NO3(-) as well as cation cavities arising from cooperative orientation of free carboxylate groups. An especially interesting feature is the structural memory effect during crystallization exhibited by the metalloligand, even after dissolution and binding to secondary cations (Cu(2+), Cd(2+)…). Moreover, the porous solid can undergo ion-exchange with various anions, leading to tunable thermochromic temperature and color range. PMID:27463609

  20. A new anionic exchange stir bar sorptive extraction coating based on monolithic material for the extraction of inorganic anion.

    Science.gov (United States)

    Huang, Xiaojia; Lin, Jianbing; Yuan, Dongxing

    2010-07-23

    A novel anionic exchange stir bar sorptive extraction (SBSE) coating based on poly(2-(methacryloyloxy)ethyltrimethylammonium chloride-co-divinylbenzene) monolithic material for the extraction of inorganic anion was prepared. The effect of preparation conditions such as ratio of functional monomer to cross-linker, content of porogenic solvent on the extraction efficiencies were investigated in detailed. The monolithic material was characterized by elemental analysis, scanning electron microscopy and infrared spectroscopy. In order to investigate the extraction capacity of the new coating for inorganic anion, the new SBSE was combined with ionic chromatography with conductivity detection, Br-, NO3-, PO4(3-) and SO4(2-) were selected as detected solutes. Several extractive parameters, including pH value and ionic strength in sample matrix, desorption solvent, extraction and desorption time were optimized. The results showed that strongly ionic strength did not favor the extraction of anlaytes. Under the optimum experimental conditions, low detection limits (S/N=3) and quantification limits (S/N=10) of the proposed method for the target anions were achieved within the range of 0.92-2.62 and 3.03-9.25 microg/L, respectively. The method also showed good linearity, simplicity, practicality and low cost for the extraction inorganic anions. Finally, the proposed method was successfully used to detect the two different trademarks of commercial purified water with satisfactory recovery in the range of 70.0-92.6%. To the best of our knowledge, this is the first to use SBSE to enrich inorganic anions. PMID:20576270

  1. Magnetic graphitic carbon nitride anion exchanger for specific enrichment of phosphopeptides.

    Science.gov (United States)

    Zhu, Gang-Tian; He, Xiao-Mei; Chen, Xi; Hussain, Dilshad; Ding, Jun; Feng, Yu-Qi

    2016-03-11

    Anion-exchange chromatography (AEX) is one of the chromatography-based methods effectively being used for phosphopeptide enrichment. However, the development of AEX materials with high specificity toward phosphopeptides is still less explored as compared to immobilized metal affinity chromatography (IMAC) or metal oxide affinity chromatography (MOAC). In this work, magnetic graphitic carbon nitride (MCN) was successfully prepared and introduced as a promising AEX candidate for phosphopeptide enrichment. Due to the extremely abundant content of nitrogen with basic functionality on the surface, this material kept excellent retention for phosphopeptides at pH as low as 1.8. Benefiting from the large binding capacity at such low pH, MCN showed remarkable specificity to capture phosphopeptides from tryptic digests of standard protein mixtures as well as nonfat milk and human serum. In addition, MCN was also applied to selective enrichment of phosphopeptides from the tryptic digests of rat brain lysate and 2576 unique phosphopeptides were successfully identified. PMID:26884140

  2. Separation of boron isotopes using NMG type anion exchange resin

    International Nuclear Information System (INIS)

    Ion exchange separation of boron isotopes (B-10 and B-11) has been studied by using a special boron selective ion exchange resin; NMG (n-methyl glucamine)-type anion exchange resin. The resin has shown a large isotope separation coefficient of 1.02 at the experimental conditions of temperature, 80degC, and boric acid concentration, 0.2 M (mole/dm3). Enriched B-10 (92%) was obtained after the migration of 1149 m by a recyclic operation of ion exchange columns in a merry-go-round method. (author)

  3. Understanding and modeling removal of anionic organic contaminants (AOCs) by anion exchange resins.

    Science.gov (United States)

    Zhang, Huichun; Shields, Anthony J; Jadbabaei, Nastaran; Nelson, Maurice; Pan, Bingjun; Suri, Rominder P S

    2014-07-01

    Ionic organic contaminants (OCs) are a growing concern for water treatment and the environment and are removed inefficiently by many existing technologies. This study examined removal of anionic OCs by anion exchange resins (AXRs) as a promising alternative. Results indicate that two polystyrene AXRs (IRA910 and IRA96) have higher sorption capacities and selectivity than a polyacrylate resin (A860). For the polystyrene resins, selectivity follows: phenolates ≥ aromatic dicarboxylates > aromatic monocarboxylates > benzenesulfonate > aliphatic carboxylates. This trend can be explained based on hydration energy, the number of exchange groups, and aromaticity and hydrophobicity of the nonpolar moiety (NPM) of the anions. For A860, selectivity only varies within a narrow range (0.13-1.64). Despite the importance of the NPM of the anions, neutral solutes were sorbed much less, indicating synergistic combinations of electrostatic and nonelectrostatic interactions in the overall sorption. By conducting multiple linear regression between Abraham's descriptors and nature log of selectivity, induced dipole-related interactions and electrostatic interactions were found to be the most important interaction forces for sorption of the anions, while solute H-bond basicity has a negative effect. A predictive model was then developed for carboxylates and phenolates based on the poly parameter linear free energy relationships established for a diverse range of 16 anions and 5 neutral solutes, and was validated by accurate prediction of sorption of five test solutes within a wide range of equilibrium concentrations and that of benzoate at different pH. PMID:24877792

  4. Purification of organic acids by chromatography with strong anionic resins: Investigation of uptake mechanisms.

    Science.gov (United States)

    Lemaire, Julien; Blanc, Claire-Line; Lutin, Florence; Théoleyre, Marc-André; Stambouli, Moncef; Pareau, Dominique

    2016-08-01

    Bio-based organic acids are promising renewable carbon sources for the chemical industry. However energy-consuming purification processes are used, like distillation or crystallization, to reach high purities required in some applications. That is why preparative chromatography was studied as an alternative separation technique. In a previous work dealing with the purification of lactic, succinic and citric acids, the Langmuir model was insufficient to explain the elution profiles obtained with a strong anionic resin. Consequently the Langmuir model was coupled with a usual ion-exchange model to take into account the retention of their conjugate bases (tailing and apparent delay observed with succinic and citric acids can be explained by the high affinity of succinate and citrate for resin cationic sites. The model was implemented in a preparative chromatography simulation program in order to optimize operating parameters of our pilot-scale ISMB unit (Improved Simulated Moving Bed). The comparison with experimental ISMB profiles was conclusive. PMID:27373374

  5. Organic resin anion exchangers for the treatment of radioactive wastes

    International Nuclear Information System (INIS)

    Organic anion exchange resins are evaluated for 99-TcO4- (pertechnate) removed from aqueous nuclear waste streams. Chemical, thermal and radiation stabilities were studied. Selected resins were examined in detail for their selectivities in the presence of I-, NO3-, SO4=, CO3=, Cl- and OH-. Ion exchange equilibria and kinetic mechanisms were determined. Preliminary investigations of cement encapsulation in polymer modified form were made and some leach studies carried out. (author)

  6. Uptake of trace elements in human hair by anion exchange

    International Nuclear Information System (INIS)

    The sorption of some trace elements to human hair is studied by means of radioactive tracers. Experiments with 59Fe, 64Cu, 65Zn, 72Ga and 115Cd in HCl media show a great similarity between human hair and Dowex 1-x10, indicating that the hair acts as a strongly basic anion exchanger. A corresponding similarity with strong cation exchangers is not found. Specific sorption of trace elements seems to be of little use in hair identification studies. (author)

  7. Studies on radiolytic degradation of anion exchange resin under acidic condition

    International Nuclear Information System (INIS)

    With a view to understand the onset of degradation phenomenon of anion exchange resin used in PUREX process for the final purification of Pu, investigation were carried out to trace the chemical signature of radiolytic degradation species soluble in nitric acidic solutions. With this aim Dowex 1x 4 anion exchange resin was subjected to radiolytic degradation in presence of water and nitric acid medium of different strengths ranging from 2M to 7M. The aqueous acidic solutions have been analysed for the presence of aqueous soluble organic fragments arising from resin matrix and change in acidity. The extracted products have also been analysed by Gas chromatography. GLC fingerprint suggest of several degradation products especially at 7M nitric acid and dose of 87 Mrad. (author)

  8. Reducing nitrogen crossover in microbial reverse-electrodialysis cells by using adjacent anion exchange membranes and anion exchange resin

    KAUST Repository

    Wallack, Maxwell J.

    2015-01-01

    Microbial reverse electrodialysis cells (MRECs) combine power generation from salinity gradient energy using reverse electrodialysis (RED), with power generation from organic matter using a microbial fuel cell. Waste heat can be used to distill ammonium bicarbonate into high (HC) and low salt concentration (LC) solutions for use in the RED stack, but nitrogen crossover into the anode chamber must be minimized to avoid ammonia loses, and foster a healthy microbial community. To reduce nitrogen crossover, an additional low concentration (LC) chamber was inserted before the anode using an additional anion exchange membrane (AEM) next to another AEM, and filled with different amounts of anion or cation ion exchange resins. Addition of the extra AEM increased the ohmic resistance of the test RED stack from 103 Ω cm2 (1 AEM) to 295 Ω cm2 (2 AEMs). However, the use of the anion exchange resin decreased the solution resistance of the LC chamber by 74% (637 Ω cm2, no resin; 166 Ω cm2 with resin). Nitrogen crossover into the anode chamber was reduced by up to 97% using 50% of the chamber filled with an anion exchange resin compared to the control (no additional chamber). The added resistance contributed by the use of the additional LC chamber could be compensated for by using additional LC and HC membrane pairs in the RED stack.

  9. High-performance liquid chromatography - Ultraviolet method for the determination of total specific migration of nine ultraviolet absorbers in food simulants based on 1,1,3,3-Tetramethylguanidine and organic phase anion exchange solid phase extraction to remove glyceride.

    Science.gov (United States)

    Wang, Jianling; Xiao, Xiaofeng; Chen, Tong; Liu, Tingfei; Tao, Huaming; He, Jun

    2016-06-17

    The glyceride in oil food simulant usually causes serious interferences to target analytes and leads to failure of the normal function of the RP-HPLC column. In this work, a convenient HPLC-UV method for the determination of the total specific migration of nine ultraviolet (UV) absorbers in food simulants was developed based on 1,1,3,3-tetramethylguanidine (TMG) and organic phase anion exchange (OPAE) SPE to efficiently remove glyceride in olive oil simulant. In contrast to the normal ion exchange carried out in an aqueous solution or aqueous phase environment, the OPAE SPE was performed in the organic phase environments, and the time-consuming and challenging extraction of the nine UV absorbers from vegetable oil with aqueous solution could be readily omitted. The method was proved to have good linearity (r≥0.99992), precision (intra-day RSD≤3.3%), and accuracy(91.0%≤recoveries≤107%); furthermore, the lower limit of quantifications (0.05-0.2mg/kg) in five types of food simulants(10% ethanol, 3% acetic acid, 20% ethanol, 50% ethanol and olive oil) was observed. The method was found to be well suited for quantitative determination of the total specific migration of the nine UV absorbers both in aqueous and vegetable oil simulant according to Commission Regulation (EU) No. 10/2011. Migration levels of the nine UV absorbers were determined in 31 plastic samples, and UV-24, UV-531, HHBP and UV-326 were frequently detected, especially in olive oil simulant for UV-326 in PE samples. In addition, the OPAE SPE procedure was also been applied to efficiently enrich or purify seven antioxidants in olive oil simulant. Results indicate that this procedure will have more extensive applications in the enriching or purification of the extremely weak acidic compounds with phenol hydroxyl group that are relatively stable in TMG n-hexane solution and that can be barely extracted from vegetable oil. PMID:27189432

  10. Cholangiocyte anion exchange and biliary bicarbonate excretion

    Institute of Scientific and Technical Information of China (English)

    Jesús M Banales; Jesús Prieto; Juan F Medina

    2006-01-01

    Primary canalicular bile undergoes a process of fluidization and alkalinization along the biliary tract that is influenced by several factors including hormones, innervation/neuropeptides, and biliary constituents. Theexcretion of bicarbonate at both the canaliculi and the bile ducts is an important contributor to the generation of the so-called bile-salt independent flow. Bicarbonate is secreted from hepatocytes and cholangiocytes through parallel mechanisms which involve chloride efflux through activation of Cl- channels, and further bicarbonate secretion via AE2/SLC4A2-mediated Cl-/HCO3-exchange. Glucagon and secretin are two relevant hormones which seem to act very similarly in their target cells (hepatocytes for the former and cholangiocytes for the latter). These hormones interact with their specific G protein-coupled receptors, causing increases in intracellular levels of cAMP and activation of cAMP-dependent Cl- and HCO3- secretory mechanisms. Both hepatocytes and cholangiocytes appear to have cAMP-responsive intracellular vesicles in which AE2/SLC4A2 colocalizes with cell specific Cl- channels (CFTR in cholangiocytes and not yet determined in hepatocytes) and aquaporins (AQP8 in hepatocytes and AQP1 in cholangiocytes). cAMP-induced coordinated trafficking of these vesicles to either canalicular or cholangiocyte lumenal membranes and further exocytosis results in increased osmotic forces and passive movement of water with net bicarbonate-rich hydrocholeresis.

  11. The immobilization of anion exchange resins in polymer modified cements

    International Nuclear Information System (INIS)

    Organic anion exchange resins, loaded with 99-Tc as the pertechnate ion, were incorporated into polymer modified cements (Flexocrete Ltd, Preston). BFS/OPC (9:1 mix) also was modified by three polymers from the same source (styrene acrylic (2) styrene butadiene) and loaded with anion exchanger containing the pertechnate. Composites were tested for initial compressive strengths, under water and radiation stability and leach rate. IAEA standard leach testing was with simulated sea and ground waters. Ground water leaching also was carried out on composites subjected to 1.109 rads (γ). Leach testing correlated well with compressive strength. Modified composites performed better than the BFS/OPC mix under all conditions studied and were able to encapsulate higher resin loadings. (author)

  12. Multilayer chitosan-based open tubular capillary anion exchange column with integrated monolithic capillary suppressor

    International Nuclear Information System (INIS)

    Highlights: ► Uses a multilayer chitosan–glutaraldehyde coating as anion exchanger. ► Uses a methacrylate-acrylic acid polymer monolith as suppressor. ► Demonstrates first integral suppressor open tubular anion chromatography. - Abstract: We describe a multilayered open tubular anion exchange column fabricated by alternately pumping solutions of chitosan and glutaraldehyde. The column is terminated in an integrally bonded monolithic suppressor cast around a mandrel of a tungsten wire, composed of an acrylic acid (AA)–ethylene dimethacrylate (EDMA) monolith that is made with sufficient porogen for the monolith to function as a membrane. For a 4.5 m long 75 μm bore column coated with 24 successive layers of the condensation polymer (estimated to contain ∼72 molecular layers) and coupled to 1 cm length of a suppressor fabricated with 55–60% AA, effective separation of several common anions (F−, Cl−, NO2−, Br−, NO3−, average number of theoretical plates ∼12,000) and adequate suppression of 1 mM KOH used as eluent was observed at a flow rate of 800 nL min−1 to obtain sub-picomol detection limits at an operating pressure of ∼1 bar. The separation is not time efficient but the system can be meritorious in unique niche applications where a small form factor is desired and liquid volume and power consumption are more important than separation speed.

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

    Science.gov (United States)

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

    2016-05-01

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

  14. A Novel Methodology to Synthesize Highly Conductive Anion Exchange Membranes

    OpenAIRE

    Yubin He; Jiefeng Pan; Liang Wu; Yuan Zhu; Xiaolin Ge; Jin Ran; ZhengJin Yang; Tongwen Xu

    2015-01-01

    Alkaline polyelectrolyte fuel cell now receives growing attention as a promising candidate to serve as the next generation energy-generating device by enabling the use of non-precious metal catalysts (silver, cobalt, nickel et al.). However, the development and application of alkaline polyelectrolyte fuel cell is still blocked by the poor hydroxide conductivity of anion exchange membranes. In order to solve this problem, we demonstrate a methodology for the preparation of highly OH− conductiv...

  15. Fixing of metallic acetates on an anion-exchange resin

    International Nuclear Information System (INIS)

    After giving a brief review of the theoretical principles governing the fixation of anionic complexes of metallic elements on an anion exchange resin, we consider the particular case of uranyl acetate. By plotting the partition curves we have been able to calculate the exchange constants in the resin. By studying the changes in the logarithm of the limiting partition coefficient as a function of the logarithm of the free acetate ion concentration, it has been possible to calculate the dissociation constants for the complexes in solution. The fixation of a large number of metallic acetates has been studied. All the tests have been negative except in the case of mercury. For this reason we have been able to consider the possibility of separating uranium from a certain number of elements. Some of these separations are possible even in the presence of interfering anions such as chlorides which have a greater affinity for the resin than have the acetate ions. In the case of water-ethanol and water-isopropanol mixtures, we have improved the conditions under which copper acetate and mercury acetate may be fixed. This study has enabled us to calculate the dissociation constant for the CuAc3- complex in the mixtures water +40% (by weight) isopropanol and water +50% (by weight) isopropanol. It should also make it possible to use separation conditions which could not hitherto be applied in aqueous media. (author)

  16. Removal of chromium complex dye from aqueous solutions using strongly basic and weakly basic anion exchangers

    OpenAIRE

    Kauspediene, D.; Kazlauskiene E.; Selskiene, A.

    2010-01-01

    Removal of chromium complex dye from aqueous solutions by sorption onto a weakly basic, acrylic matrix anion exchanger Purolite A845 and a strongly basic, polystyrene matrix anion exchanger Purolite A 500P has been investigated under various experimental conditions: the initial dye concentration, pH and temperature. The sorption of chromium complex dye proceeds as a result of miscellaneous interactions between the dye and anion exchanger: ion exchange and physical sorption. The removal effici...

  17. Anion exchange selectivity of surfactant modified clinoptilolite-rich tuff for environmental remediation.

    Science.gov (United States)

    de Gennaro, Bruno; Catalanotti, Lilia; Bowman, Robert S; Mercurio, Mariano

    2014-09-15

    Lately, the functionalization of industrial minerals with high technological properties, such as natural zeolites, is shaping as a promising approach in environmental sphere. In fact, under the specific conditions, the surface functionalization via adsorption of cationic surfactants reverses the surface charge of the mineral, enabling zeolites to simultaneously interact either with organic contaminants or inorganic anions. This aspect allows zeolites to be used in the remediation of contaminated fluids. The present research shed new light on some still not fully understood aspects concerning exchange kinetics such as anion-exchange mechanisms and selectivity of surface modified minerals. For this purpose the mineralogical characterization and the surface properties evaluation (X Ray Powder Diffraction, chemical analysis, thermal analysis, ECEC and AEC) of a clinoptilolite-rich tuff were performed, and the anion exchange isotherms of the sample, modified with hexadecyltrimethylammonium chloride or bromide (HDTMA-Cl/-Br), were determined. Ion-exchange equilibrium data of uni-uni valent reaction were obtained by solutions containing Br(-), Cl(-), NO3(-) or ClO4(-). Liquid phase was analysed via high performance liquid chromatography. Thermodynamic quantities (Ka and ΔG(0)) were determined and compared with the Hofmeister series. The value of the ECEC, calculated in batch conditions, was about 137 mmol/kg, in good agreement with that evaluated in dynamic conditions, while the AEC data were different for the SMNZ-Br and -Cl samples, amounting to 137 and 106 mmol/kg, respectively, thus indicating a different compactness of the bilayer formed in the two cases. Moreover, the anion isotherm results and the mathematical evaluation of the thermodynamic parameters, demonstrated the good affinity of SMNZ-Br towards chloride, nitrate and perchlorate, and of SMNZ-Cl for nitrate and perchlorate, also endorsing the possibility of using the same thermodynamic approach developed to

  18. Fixation of metallic sulfosalicylate complexes on an anionic exchange resin

    International Nuclear Information System (INIS)

    Since sulfosalicylate ions have acid-base properties, sulfosalicylate complexes have an apparent stability which varies with the ph. As a result, the fixation of sulfo-salicylates on an anionic exchange resin depends on the ph of the solution in equilibrium with the resin. This research has been aimed at studying the influence of the ph on the fixation on an anionic exchange resin (Dowex 1 x 4) of sulfosalicylate anions on the one hand, and of metallic sulfosalicylate complexes on the other hand. In the first part of this work, a determination has been made, by frontal analysis of the distribution of sulfosalicylate ions in the resin according to the total sulfosalicylate I concentration in the aqueous solution in equilibrium with the resin. The exchange constants of these ions between the resin and the solution have been calculated. In the second part, a study has been made of the fixation of anionic sulfosalicylate complexes of Fe(III), Al(III), Cr(III), Cu(II), Ni(II), Co(II), Zn(II), Mn(II), Cd(II), Fe(II) and UO22+. By measuring the partition coefficients of these different elements between the resin and the solution it has been possible to give interpretation for the modes of fixation of the metallic ions, and to calculate their exchange constant between the resin and the solution. The relationship has been established for each metallic element studied, between its partition coefficient, the ph and the total concentration of the complexing agent in solution. Such a relationship makes it possible to predict, for given conditions, the nature of the species in solution and in the resin, as well as the partition coefficient of a metallic, element. Finally, in the third part of the work, use has been made of results obtained previously, to carry out some separations (Ni2+ - Co2+; Ni2+ - Co2+ - Cu2+; UO22+ - Fe3+; UO22+ - Cr3+; UO22+ - Cu2+; UO22+ - Ni2+; UO22+ - Co2+; UO22+ - Mn2+ and UO22+ - Cd2+), as well as the purification of a uranyl sulfosalicylate solution

  19. Separation of iron-55 from manganese cyclotron target material on a 2% cross-linked anion exchanger in hydrochloric acid

    International Nuclear Information System (INIS)

    A simple method is presented for the separation of iron-55 from manganese cyclotron targets. Anion exchange chromatography with 9.0 M hydrochloric acid on a 2% cross-linked resin provides separation not only from large amounts of manganese but also from copper and zinc impurities. Separations are sharp and quantitative and less than 1 μg of manganese remains with the iron-55 when 2 g have been present originally. (author)

  20. Comparison among three anion exchange chromatographic supports to capture erythropoietin from cell culture supernatant

    Institute of Scientific and Technical Information of China (English)

    Lourdes HERNNDEZ; Diobel STEWART; Lourdes ZUMALACRREGUI; Daniel AMARO

    2015-01-01

    Affinity and ion exchange conventional chromatography have been used to capture erythropoietin ( EPO)from mammalian cell culture supernatant. Currently,chromatographic adsorbent perfusion is available, however a limited number of applications have been found in the literature. In this work,three anion exchange chromatographic supports( gel,membrane and monolithic)were evaluated in the capture step of the recombi-nant erythropoietin purification process. The influences of load and flow rate on each support performance were analyzed. Also the purity of the EPO molecules was determined. A productivity analysis,as a decision tool for larger scale implementation,was done. As a conclusion,the evaluated supports are technically suitable to cap-ture EPO with adequate recovery and good purity. However,the monolithic column admits high operating velocity,showing the highest adsorption capacity and productivity.

  1. The sorption capacity of boron on anionic-exchange resin

    International Nuclear Information System (INIS)

    Boron sorption capacities on anionic-exchange resins vary with temperature, concentration, and resin cross-linkage. A semiempirical correlation, developed from boron solution chemistry, is presented to account for these variations. The relationship, based on boron chemistry and changes in Gibb's energy, can be stated approximately as Q = a1CBa2Za3 exp[-(a4T + a5T2 + a6Z0.5)]. Correlation parameters, which vary with resin type, are evaluated experimentally. Parameter values for macroporous resin Diaion PA 300 and for gel-type resins Diaion SA10 and Amberlite IRN 78LC are presented. The resulting expression is used to determine boron sorption and desorption limitations on ion exchangers at various temperatures and concentrations, and to determine the interfacial boron concentration in equilibrium and rate models

  2. Anion exchange kinetics of uranium in sulphate media

    International Nuclear Information System (INIS)

    Experiments have shown that the sorption of uranium from acidic sulphate solutions onto strong base-anion exchange resins is particle diffusion controlled in the uranium concentration range 0.0001 to 0.004 M. A simplified diffusion model, based on Fick's Law, fits the kinetic data at each concentration. The rate of sorption falls significantly at lowered solution concentration. This corresponds with a lowered equilibrium loading of uranium and can be predicted with the Nernst-Planck equations using the measured self diffusion coefficient of uranium (1.65 x 10-8 cm2/s) and sulphate ions. The importance of this lowering of uranium sorption on the design of ion exchange equipment is stressed. (author)

  3. A Novel Methodology to Synthesize Highly Conductive Anion Exchange Membranes

    Science.gov (United States)

    He, Yubin; Pan, Jiefeng; Wu, Liang; Zhu, Yuan; Ge, Xiaolin; Ran, Jin; Yang, Zhengjin; Xu, Tongwen

    2015-08-01

    Alkaline polyelectrolyte fuel cell now receives growing attention as a promising candidate to serve as the next generation energy-generating device by enabling the use of non-precious metal catalysts (silver, cobalt, nickel et al.). However, the development and application of alkaline polyelectrolyte fuel cell is still blocked by the poor hydroxide conductivity of anion exchange membranes. In order to solve this problem, we demonstrate a methodology for the preparation of highly OH- conductive anion exchange polyelectrolytes with good alkaline tolerance and excellent dimensional stability. Polymer backbones were grafted with flexible aliphatic chains containing two or three quaternized ammonium groups. The highly flexible and hydrophilic multi-functionalized side chains prefer to aggregate together to facilitate the formation of well-defined hydrophilic-hydrophobic microphase separation, which is crucial for the superior OH- conductivity of 69 mS/cm at room temperature. Besides, the as-prepared AEMs also exhibit excellent alkaline tolerance as well as improved dimensional stability due to their carefully designed polymer architecture, which provide new directions to pursue high performance AEMs and are promising to serve as a candidate for fuel cell technology.

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

    Science.gov (United States)

    Johnson, Brian J.

    2014-01-01

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

  5. Investigation of Polyacrylate Anion-Exchangers for Separation of Rare Earth Element Complexes with EDTA

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The rare earth complexes with EDTA, Ln(edta), show an unusual sequence of affinity for the anion-exchangers. The sorption and chromatographic separation of Y3+ for Nd3+ complexes with EDTA was studied by using the strongly basic gel and macroporous polyacrylate anion-exchangers, Amberlite IRA 458 and Amberlite 958, and the weakly basic gel polyacrylate anion-exchanger, Amberlite IRA-68. The investigations on sorption and separation of rare earth complexes with EDTA on the polyacrylate anion-exchangers applied mainly in the environment protection so far indicate that they can be applied in anionexchange separation of lanthanide complexes with aminopolycarboxylic acids. It was shown that the weakly basic polyacrylate gel anion-exchanger Amberlite IRA-68 is the most effective in purification of Y3+ from Nd3+ in comparison with the strongly basic anion-exchangers of this type.

  6. Computer simulation of methanol exchange dynamics around cations and anions

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Santanu; Dang, Liem X.

    2016-03-03

    In this paper, we present the first computer simulation of methanol exchange dynamics between the first and second solvation shells around different cations and anions. After water, methanol is the most frequently used solvent for ions. Methanol has different structural and dynamical properties than water, so its ion solvation process is different. To this end, we performed molecular dynamics simulations using polarizable potential models to describe methanol-methanol and ion-methanol interactions. In particular, we computed methanol exchange rates by employing the transition state theory, the Impey-Madden-McDonald method, the reactive flux approach, and the Grote-Hynes theory. We observed that methanol exchange occurs at a nanosecond time scale for Na+ and at a picosecond time scale for other ions. We also observed a trend in which, for like charges, the exchange rate is slower for smaller ions because they are more strongly bound to methanol. This work was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences. The calculations were carried out using computer resources provided by the Office of Basic Energy Sciences.

  7. Anion-exchangeable inorganic-organic hybrid materials synthesized without using templates

    Institute of Scientific and Technical Information of China (English)

    XU Xianzhu; SONG Jiangwei; LI Defeng; XIAO Fengshou

    2004-01-01

    Inorganic-organic hybrid materials have been obtained at room temperature in aqueous solution without using the templates of surfactants. The materials are care fully characterized by anion-exchange measurement, elements analysis, X-ray diffraction, and infrared spectroscopy. Notably, the anion-exchange capacity of the samples (3.9 Interestingly, both small and large anions could be easily exchanged into the samples due to the plasticity of the sam pies, along with the phase transition.

  8. Optimized anion exchange membranes for vanadium redox flow batteries.

    Science.gov (United States)

    Chen, Dongyang; Hickner, Michael A; Agar, Ertan; Kumbur, E Caglan

    2013-08-14

    In order to understand the properties of low vanadium permeability anion exchange membranes for vanadium redox flow batteries (VRFBs), quaternary ammonium functionalized Radel (QA-Radel) membranes with three ion exchange capacities (IECs) from 1.7 to 2.4 mequiv g(-1) were synthesized and 55-60 μm thick membrane samples were evaluated for their transport properties and in-cell battery performance. The ionic conductivity and vanadium permeability of the membranes were investigated and correlated to the battery performance through measurements of Coulombic efficiency, voltage efficiency and energy efficiency in single cell tests, and capacity fade during cycling. Increasing the IEC of the QA-Radel membranes increased both the ionic conductivity and VO(2+) permeability. The 1.7 mequiv g(-1) IEC QA-Radel had the highest Coulombic efficiency and best cycling capacity maintenance in the VRFB, while the cell's voltage efficiency was limited by the membrane's low ionic conductivity. Increasing the IEC resulted in higher voltage efficiency for the 2.0 and 2.4 mequiv g(-1) samples, but the cells with these membranes displayed reduced Coulombic efficiency and faster capacity fade. The QA-Radel with an IEC of 2.0 mequiv g(-1) had the best balance of ionic conductivity and VO(2+) permeability, achieving a maximum power density of 218 mW cm(-2) which was higher than the maximum power density of a VRFB assembled with a Nafion N212 membrane in our system. While anion exchange membranes are under study for a variety of VRFB applications, this work demonstrates that the material parameters must be optimized to obtain the maximum cell performance. PMID:23799776

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

    Science.gov (United States)

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

    2016-01-01

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

  10. A Simple Halide-to-Anion Exchange Method for Heteroaromatic Salts and Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Neus Mesquida

    2012-04-01

    Full Text Available A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A− form in non-aqueous media. The anion loading of the AER (OH− form was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A− form method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH3OH, CH3CN and the dipolar nonhydroxylic solvent mixture CH3CN:CH2Cl2 (3:7 and the anion exchange was equally successful with both lipophilic cations and anions.

  11. Reillex/trademark/ HPQ: A new, macroporous polyvinylpyridine resin for separating plutonium using nitrate anion exchange

    International Nuclear Information System (INIS)

    Anion exchange in nitric acid is the major aqueous process used to recover and purify plutonium from impure scrap materials. Most strong-base anion exchange resins incorporate a styrene-divinylbenzene copolymer. A newly available, macroporous anion exchange resin based on a copolymer of 1-methyl-4-vinylpyridine and divinylbenzene has been evaluated. Comparative data for Pu(IV) sorption kinetics and capacity are presented for this new resin and two other commonly used anion exchange resins. The new resin offers high capacity and rapid sorption kinetics for Pu(IV) from nitric acid, as well as greater stability to chemical and radiolytic degradation. 8 refs., 12 figs

  12. Performance of selected anion exchange resins for the treatment of a high DOC content surface water.

    Science.gov (United States)

    Humbert, Hugues; Gallard, Hervé; Suty, Hervé; Croué, Jean-Philippe

    2005-05-01

    The objective of this study was first to compare the performance of four strong anion exchange resins (AERs) (MIEX from Orica Pty Ltd, DOWEX-11 and DOWEX-MSA from DOW chemical and IRA-938 from Rohm and Haas) for their application in drinking water treatment (natural organic matter (NOM), mineral anions (nitrate, sulfate and bromide) and pesticide removal) using bench-scale experimental procedures on a high DOC content surface water. The efficiency of MIEX for NOM and mineral anions removal was furthermore evaluated using bench-scale dose-response experiments on raw, clarified and post-ozonated waters. NOM removal was assessed using the measurement of dissolved organic carbon (DOC), UV absorbance at 254 nm (UV254) and the use of high-performance size exclusion chromatography with UV (HPSEC/UV) and fluorescence detection (HPSEC/FLUO). The MIEX and IRA938 anionic resins exhibit a faster removal of NOM and mineral anions compared to the DOWEX11 and MSA AERs. All the resins were found to be very effective with similar performances after 30 to 45 min of contact time. As expected, only limited sorption of atrazine and isoproturon (C0=1 microg/L) occurred with MIEX, DOWEX11 and MSA AERs. MIEX resin proved to be very efficient in eliminating NOM of high-molecular weight but also a large part of the smallest UV absorbing organic compounds which were refractory to coagulation/flocculation treatment. Remaining DOC levels after 30 min of contact with MIEX were found similar in raw water, clarified water and even post-ozonated water implying no DOC benefit can be gained by employing conventional treatment prior to MIEX treatment. Removal of bromide (initial concentration 110 microg/L) was also observed and ranged from 30% to 65% for resin dose increasing from 2 to 8 mL/L. T PMID:15899268

  13. Determination of free and total myo-inositol in infant formula and adult/pediatric nutritional formula by high- performance anion exchange chromatography with pulsed amperometric detection, including a novel total extraction using microwave-assisted acid hydrolysis and enzymatic treatment: first action 2012.12.

    Science.gov (United States)

    Ellingson, David; Pritchard, Ted; Foy, Pamela; King, Kathryn; Mitchell, Barbara; Austad, John; Winters, Doug; Sullivan, Darryl; Dowell, Dawn

    2013-01-01

    After an assessment of data generated from a single-laboratory validation study published in J. AOAC Int. 95, 1469-1478 (2012), a method for determining total myo-inositol in infant formula and adult/ pediatric nutritional formula by high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), including extraction by using microwave-assisted acid hydrolysis and enzymatic treatment was presented for consideration by AOAC during the AOAC Annual Meeting held in Las Vegas, NV, from September 30 to October 3, 2012. The Expert Review Panel on Infant Formula and Adult Nutritionals concluded that the method met the criteria set by the standard method performance requirements (SMPRs) for the determination of free myo-inositol and approved the method as AOAC Official First Action. The method also determines total myo-inositol, but includes bound sources that the SMPRs exclude. The method involves using HPAEC-PAD for free myo-inositol and a total myo-inositol determination by two different techniques. The first technique uses the conventional acid hydrolysis with 6 h incubation in an autoclave. The second uses a microwave-assisted acid hydrolysis with enzymatic treatment that decreases the extraction time. PMID:24282949

  14. Liquid anion-exchange separation of vanadium from malonate media

    International Nuclear Information System (INIS)

    Vanadium (IV) and (V) can be quantitatively extracted with 0.2 mol/l Amberlite LA-2 in xylene at pH 3.0 from 0.02 mol/l malonic acid, stripped with 0.5 mol/l hydrochloric acid, and determined spectrophotometrically. Five other liquid anion exchangers (Amberlite LA-1, Primene JM-T, Aliquat 336S, TOA and TIOA) were examined as possible extractants. The extraction of vanadium(IV) was found to be quantitative only with Amberlite LA-2, while that of vanadium(V) was quantitative with Amberlite LA-1 and LA-2, Primene JM-T and Aliquat 336S. Eight common solvents were tested as diluents; of these hexane, cyclohexane, benzene, and xylene were found to be satisfactory. Vanadium was separated from elements that do not form anionic complexes with malonic acid by selective extraction, from those that form weak complexes by washing the organic extract with water, and from metals that form strong malonato complexes by selective stripping with hydrochloric, nitric, or sulphuric acid. The method has been applied to the determination of vanadium in steel, coal fly ash and fuel oil. The precision of measurement is within ±5% and the detection limit of the method for vanadium is 0.5 mg/kg. (orig.)

  15. The anion exchange behavior of Te and Sb

    International Nuclear Information System (INIS)

    The absorption behavior of Te and Sb in different oxidation states by anion exchange resins in hydrochloric acid medium has been studied. Distribution coefficients for Te(IV), Te(VI) as a function of HCl acid concentration (up to 3M HCl) have been determined. The absorbability for Sb(III) was noticed to be very high and could not be eluted out of the column using HCl as eluent. Sb(V) could be eluted quantitatively using 3M HCl. The present study clearly indicate that due to the EC/β+ decay of the parent isotopes 117,118Te, the daughter nuclei 117,118Sb are produced predominantly as Sb(III). (author)

  16. Alkaline direct alcohol fuel cells using an anion exchange membrane

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, Koji; Iriyama, Yasutoshi; Abe, Takeshi; Ogumi, Zempachi [Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Matsuoka, Masao [Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan)

    2005-10-04

    Alkaline direct alcohol fuel cells using an OH-form anion exchange membrane and polyhydric alcohols were studied. A high open circuit voltage of ca. 800mV was obtained for a cell using Pt-Ru/C (anode) and Pt/C (cathode) at 323K, which was about 100-200mV higher than that for a DMFC using Nafion{sup R}. The maximum power densities were in the order of ethylene glycol>glycerol>methanol>erythritol>xylitol. Silver catalysts were used as a cathode catalyst to fabricate alkaline fuel cells, since silver catalyst is almost inactive in the oxidation of polyhydric alcohols. Alkaline direct ethylene glycol fuel cells using silver as a cathode catalyst gave excellent performance because higher concentrations of fuel could be supplied to the anode. (author)

  17. 3D Printing of Micropatterned Anion Exchange Membranes.

    Science.gov (United States)

    Seo, Jiho; Kushner, Douglas I; Hickner, Michael A

    2016-07-01

    Micropatterned anion exchange membranes (AEMs) have been 3D printed via a photoinitiated free radical polymerization and quaternization process. The photocurable formulation, consisting of diurethane dimethacrylate (DUDA), poly(ethylene glycol) diacrylate (PEGDA), dipentaerythritol penta-/hexa- acrylate, and 4-vinylbenzyl chloride (VBC), was directly cured into patterned films using a custom 3D photolithographic printing process similar to stereolithography. Measurements of water uptake, permselectivity, and ionic resistance were conducted on the quaternized poly(DUDA-co-PEGDA-co-VBC) sample series to determine their suitability as ion exchange membranes. The water uptake of the polymers increased as the ion exchange capacity (IEC) increased due to greater quaternized VBC content. Samples with IEC values between 0.98 to 1.63 mequiv/g were synthesized by varying the VBC content from 15 to 25 wt %. The water uptake was sensitive to the PEGDA content in the network resulting in water uptake values ranging from 85 to 410 wt % by varying the PEGDA fractions from 0 to 60 wt %. The permselectivity of the AEM samples decreased from 0.91 (168 wt %, 1.63 mequiv/g) to 0.85 (410 wt %, 1.63 mequiv/g) with increasing water uptake and to 0.88 (162 wt %, 0.98 mequiv/g) with decreasing IEC. Permselectivity results were relatively consistent with the general understanding of the correlation between permselectivity, water uptake, and ion content of the membrane. Lastly, it was revealed that the ionic resistance of patterned membranes was lower than that of flat membranes with the same material volume or equivalent thickness. A parallel resistance model was used to explain the influence of patterning on the overall measured ionic resistance. This model may provide a way to maximize ion exchange membrane performance by optimizing surface patterns without chemical modification to the membrane. PMID:27218137

  18. The k{sub 0}-INAA method for the determination of the anion-exchange capacity of propylpyridium silicas

    Energy Technology Data Exchange (ETDEWEB)

    Auler, Lucia M.L.A.; Menezes, Maria Angela de B.C.; Amaral, Angela Maria [Centro de Desenvolvimento de Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil)]. E-mail: aulerlm@cdtn.br; Silva, Cesar R.; Collins, Kenneth E.; Collins, Carol [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica. Lab. de Cromatografia Liquida (LABCROM)]. E-mail: chc@iqm.unicamp.br

    2005-07-01

    The present work describes the k{sub 0}-INAA method as an alternative for determination of the ion-exchange capacity of a propyl pyridinium modified silica, which has been recently employed as stationary phase for anion -exchange chromatography. The exchange capacity of the modified silicas was investigated by determining its exchangeable chloride content with k{sub 0}-Instrumental Neutron Activation Analyses. Irradiation experiments were performed in the reactor TRIGA Mark I IPR-R1 located at CDTN/CNEN (Nuclear Technology Development Center / Nuclear Energy National Commission). The results showed that the exchangeable chloride concentration was successfully determined by this analytical method instead of the conventional potentiometric determination with silver nitrate titrimetry. (author)

  19. Removal of bromide and natural organic matter by anion exchange.

    Science.gov (United States)

    Hsu, Susan; Singer, Philip C

    2010-04-01

    Bromide removal by anion exchange was explored for various water qualities, process configurations, and resin characteristics. Simulated natural waters containing different amounts of natural organic matter (NOM), bicarbonate, chloride, and bromide were treated with a polyacrylate-based magnetic ion exchange (MIEX) resin on a batch basis to evaluate the effectiveness of the resin for removal of bromide. While bromide removal was achieved to some degree, alkalinity (bicarbonate), dissolved organic carbon (DOC), and chloride were shown to inhibit bromide removal in waters with bromide concentrations of 100 and 300 microg/L. Water was also treated using a two-stage batch MIEX process. Two-stage treatment resulted in only a slight improvement in bromide removal compared to single-stage treatment, presumably due to competition with the high concentration of chloride which is present along with bromide in natural waters. In view of the relatively poor bromide removal results for the MIEX resin, a limited set of experiments was performed using polystyrene resins. DOC and bromide removal were compared by treating model waters with MIEX and two polystyrene resins, Ionac A-641 and Amberlite IRA910. The two polystyrene resins were seen to be more effective for bromide removal, while the MIEX resin was more effective at removing DOC. PMID:20045170

  20. Gamma radiation effect on gas production in anion exchange resins

    International Nuclear Information System (INIS)

    Radiation-induced decomposition of Amberlite IRA400 anion exchange resin in hydroxide form by gamma radiolysis has been studied at various doses in different atmospheres (anaerobic, anaerobic with liquid water, and aerobic). The effect of these parameters on the degradation of ion exchange resins is rarely investigated in the literature. We focused on the radiolysis gases produced by resin degradation. When the resin was irradiated under anaerobic conditions with liquid water, the liquid phase over the resin was also analyzed to identify any possible water-soluble products released by degradation of the resin. The main products released are trimethylamine (TMA), molecular hydrogen (H2g) and carbon dioxide (CO2g). TMA and H2g are produced in all the irradiation atmospheres. However, TMA was in gaseous form under anaerobic and aerobic conditions and in aqueous form in presence of liquid water. In the latter conditions, TMAaq was associated with aqueous dimethylamine (DMAaq), monomethylamine (MMAaq) and ammonia (NH4+aq). CO2g is formed in the presence of oxygen due to oxidation of organic compounds present in the system, in particular the degradation products such as TMAg

  1. Hydroxide Solvation and Transport in Anion Exchange Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chen [Univ. of Chicago, IL (United States); Wuhan Univ. (China); Tse, Ying-Lung Steve [Univ. of Chicago, IL (United States); Lindberg, Gerrick E. [Northern Arizona Univ., Flagstaff, AZ (United States); Knight, Chris [Argonne National Lab. (ANL), Argonne, IL (United States); Voth, Gregory A. [Univ. of Chicago, IL (United States)

    2016-01-27

    Understanding hydroxide solvation and transport in anion exchange membranes (AEMs) can provide important insight into the design principles of these new membranes. To accurately model hydroxide solvation and transport, we developed a new multiscale reactive molecular dynamics model for hydroxide in aqueous solution, which was then subsequently modified for an AEM material. With this model, we investigated the hydroxide solvation structure and transport mechanism in the membrane. We found that a relatively even separation of the rigid side chains produces a continuous overlapping region for hydroxide transport that is made up of the first hydration shell of the tethered cationic groups. Our results show that hydroxide has a significant preference for this overlapping region, transporting through it and between the AEM side chains with substantial contributions from both vehicular (standard diffusion) and Grotthuss (proton hopping) mechanisms. Comparison of the AEM with common proton exchange membranes (PEMs) showed that the excess charge is less delocalized in the AEM than the PEMs, which is correlated with a higher free energy barrier for proton transfer reactions. The vehicular mechanism also contributes considerably more than the Grotthuss mechanism for hydroxide transport in the AEM, while our previous studies of PEM systems showed a larger contribution from the Grotthuss mechanism than the vehicular mechanism for proton transport. The activation energy barrier for hydroxide diffusion in the AEM is greater than that for proton diffusion in PEMs, implying a more significant enhancement of ion transport in the AEM at elevated temperatures.

  2. Determination of arsenate in water by anion selective membrane electrode using polyurethane–silica gel fibrous anion exchanger composite

    International Nuclear Information System (INIS)

    Highlights: • PU–Si gel is new anion exchanger material synthesized and characterized. • This material used as anion exchange membrane is applied for electroanalytical studies. • The method for detection and determination of AsO43− in traces amounts discussed. • The results are also verified from arsenic analyzer. -- Abstract: Polyurethane (PU)–silica (Si gel) based fibrous anion exchanger composites were prepared by solid–gel polymerization of polyurethane in the presence of different amounts of silica gel. The formation of PU–Si gel fibrous anion exchanger composite was characterized by Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), scanning electron microscopy (SEM) and elemental analysis. The membrane having a composition of 5:3 (PU:Si gel) shows best results for water content, porosity, thickness and swelling. Our studies show that the present ion selective membrane electrode is selective for arsenic, having detection limit (1 × 10−8 M to 1 × 10−1 M), response time (45 s) and working pH range (5–8). The selectivity coefficient values for interfering ions indicate good selectivity for arsenate (AsO43−) over interfering anions. The accuracy of the detection limit results was compared by PCA-Arsenomat

  3. Determination of phytate in high molecular weight, charged organic matrices by two-dimensional size exclusion-ion chromatography

    Science.gov (United States)

    A two-dimensional chromatography method for analyzing anionic targets (specifically phytate) in complex matrices is described. Prior to quantification by anion exchange chromatography, the sample matrix was prepared by size exclusion chromatography, which removed the majority of matrix complexities....

  4. Test procedure for cation exchange chromatography

    International Nuclear Information System (INIS)

    The purpose of this test plan is to demonstrate the synthesis of inorganic antimonate ion exchangers and compare their performance against the standard organic cation exchangers. Of particular interest is the degradation rate of both inorganic and organic cation exchangers. This degradation rate will be tracked by determining the ion exchange capacity and thermal stability as a function of time, radiation dose, and chemical reaction

  5. Evaluation of indigenous anion exchange resins for plutonium purification - effect of gamma radiation

    International Nuclear Information System (INIS)

    The purification and concentration of plutonium is carried out presently with an imported anion exchange resin (Dowex 1X4). A programme has been initiated in our laboratory to substitute the same with indigenous resins. In this connection, the effect of gamma radiation on imported and indigenous anion exchange resins has been studied in nitric acid medium and its influence on total exchange capacity, strong base capacity and plutonium distribution ratio (Kd) are presented in this paper. (author)

  6. Sorption of Pu(IV) from nitric acid by bifunctional anion-exchange resins

    International Nuclear Information System (INIS)

    Anion exchange is attractive for separating plutonium because the Pu(IV) nitrate complex is very strongly sorbed and few other metal ions form competing anionic nitrate complexes. The major disadvantage of this process has been the unusually slow rate at which the Pu(IV) nitrate complex is sorbed by the resin. The paper summarizes the concept of bifunctional anion-exchange resins, proposed mechanism for Pu(IV) sorption, synthesis of the alkylating agent, calculation of Kd values from Pu(IV) sorption results, and conclusions from the study of Pu(IV) sorption from 7M nitric acid by macroporous anion-exchange resins including level of crosslinking, level of alkylation, length of spacer, and bifunctional vs. monofunctional anion-exchange resins

  7. High throughput determination of cleaning solutions to prevent the fouling of an anion exchange resin.

    Science.gov (United States)

    Elich, Thomas; Iskra, Timothy; Daniels, William; Morrison, Christopher J

    2016-06-01

    Effective cleaning of chromatography resin is required to prevent fouling and maximize the number of processing cycles which can be achieved. Optimization of resin cleaning procedures, however, can lead to prohibitive material, labor, and time requirements, even when using milliliter scale chromatography columns. In this work, high throughput (HT) techniques were used to evaluate cleaning agents for a monoclonal antibody (mAb) polishing step utilizing Fractogel(®) EMD TMAE HiCap (M) anion exchange (AEX) resin. For this particular mAb feed stream, the AEX resin could not be fully restored with traditional NaCl and NaOH cleaning solutions, resulting in a loss of impurity capacity with resin cycling. Miniaturized microliter scale chromatography columns and an automated liquid handling system (LHS) were employed to evaluate various experimental cleaning conditions. Cleaning agents were monitored for their ability to maintain resin impurity capacity over multiple processing cycles by analyzing the flowthrough material for turbidity and high molecular weight (HMW) content. HT experiments indicated that a 167 mM acetic acid strip solution followed by a 0.5 M NaOH, 2 M NaCl sanitization provided approximately 90% cleaning improvement over solutions containing solely NaCl and/or NaOH. Results from the microliter scale HT experiments were confirmed in subsequent evaluations at the milliliter scale. These results identify cleaning agents which may restore resin performance for applications involving fouling species in ion exchange systems. In addition, this work demonstrates the use of miniaturized columns operated with an automated LHS for HT evaluation of chromatographic cleaning procedures, effectively decreasing material requirements while simultaneously increasing throughput. Biotechnol. Bioeng. 2016;113: 1251-1259. © 2015 Wiley Periodicals, Inc. PMID:26552005

  8. Purification of degraded TBP solvent using macroreticular anion exchange resin

    International Nuclear Information System (INIS)

    Tri-n-butyl phosphate (TBP) diluted with a suitable diluent is commonly used for solvent extraction in Purex process for the recovery of uranium and plutonium from irradiated nuclear fuels. This solvent gets degraded due to various factors, the main degradation product being dibutyl phosphoric acid (HDBP). A solvent cleanup step is generally incorporated in the process for removing the degradation products from the used solvent. A liquid-liquid cleanup system using sodium carbonate or sodium hydroxide solution is routinely used. Considering certain advantages, like the possibility of loading the resin almost to saturation capacity and the subsequent disposal of the spent resin by incineration and the feasibility of adopting it to the process, a liquid-solid system has been tried as an alternate method, employing various available macroreticular anion exchange resins in OH- form for the sorption of HDBP from TBP. After standardizing the various conditions for the satisfactory removal of HDBP from TBP using synthetic mixtures, resins were tested with process solvent in batch contacts. The parameters studied were (1) capacity of different resins for HDBP sorption (2) influence of acidity, uranium and HDBP on the sorption behaviour of the latter (3) removal of fission products from the solvent by the resin and (4) regeneration and recycling of the resin. (author). 2 figs., 13 tabs., 17 refs

  9. Anion-exchange sorption of molybdate and germanate

    Energy Technology Data Exchange (ETDEWEB)

    Kislinskaya, G.E.; Denisova, T.I.; Sheka, I.A.

    1983-07-20

    Interest in sorption of molybdenum and germanium from salt solutions is prompted by industrial requirements related to purification of such solutions and also to extraction of these elements from various industrial liquors.In order to identify the ionic forms of molybdenum and germanium having the highest sorption activity and to determine the optimal conditions for extraction of these elements from solutions with high electrolyte contents, we studied the states of molybdenum(VI) and germanium(IV) in solutions of sodium chloride in various concentrations, and sorption of these elements by strongly basic macroporous anion-exchange resins and by iron and aluminum hydroxides in relation to the pH, concentrations of the elements, and time of contact between the solution and the sorbent. Examination of literature data shows that the molecular and ionic states of these elements in the presence of high salt concentrations have been studied mainly in acidic solutions and at higher molybdenum and germanium concentrations. However, for selection of a method of removal of molybdenum and germanium from production liquors it is also necessary to have analogous information on their states when present in microconcentrations over wide ranges of pH.

  10. Anion-exchange sorption of molybdate and germanate

    International Nuclear Information System (INIS)

    Interest in sorption of molybdenum and germanium from salt solutions is prompted by industrial requirements related to purification of such solutions and also to extraction of these elements from various industrial liquors.In order to identify the ionic forms of molybdenum and germanium having the highest sorption activity and to determine the optimal conditions for extraction of these elements from solutions with high electrolyte contents, we studied the states of molybdenum(VI) and germanium(IV) in solutions of sodium chloride in various concentrations, and sorption of these elements by strongly basic macroporous anion-exchange resins and by iron and aluminum hydroxides in relation to the pH, concentrations of the elements, and time of contact between the solution and the sorbent. Examination of literature data shows that the molecular and ionic states of these elements in the presence of high salt concentrations have been studied mainly in acidic solutions and at higher molybdenum and germanium concentrations. However, for selection of a method of removal of molybdenum and germanium from production liquors it is also necessary to have analogous information on their states when present in microconcentrations over wide ranges of pH

  11. Anion-exchange separations of metal ions in thiocyanate media.

    Science.gov (United States)

    Fritz, J S; Kaminski, E E

    1971-05-01

    The analytical potential of a weak-base macroreticular anion-exchange resin for the quantitative separation of metal ions in thiocyanate media is investigated and demonstrated. Distribution data are given for the sorption of some 25 metal ions from aqueous mixtures of potassium thiocyanate (1.0M or less) and 0.5M hydrochloric acid. The magnitude of the distribution data suggests many possible separations, some of which were quantitatively performed by procedures which are fast, simple and require only mild conditions. Representative separations are removal of traces of iron(III) and copper(II) from water samples prior to the determination of water hardness (calcium and magnesium), separation of nickel(II) from vanadium(IV) and the separation of thorium(IV) from titanium(IV). Some multicomponent separations are the separation of rare earths(III) and thorium(IV) from scandium(III) and the separation of rare earths(III) from iron(III) and uranium(VI). PMID:18960914

  12. Fouling mitigation of anion exchange membrane by zeta potential control.

    Science.gov (United States)

    Park, Jin-Soo; Lee, Hong-Joo; Choi, Seok-Ju; Geckeler, Kurt E; Cho, Jaeweon; Moon, Seung-Hyeon

    2003-03-15

    The feasibility of fouling mitigation of anion exchange membranes (AEMs) in the presence of humate was studied by adding three different types of water-soluble polymers, i.e., poly(acrylic acid) (PAA), poly(vinyl alcohol) (PVA), and poly(ethylene imine) (PEI), during electrodialysis (ED) desalination. Measurement of zeta potential of the humate used in this study showed highly negative potential (about -30 mV), implying that the humate had a strong fouling potential on the AEMs in ED. Of the three water-soluble polymers, PEI showed a positive zeta potential (about +14 mV) and is able to form an interpolymer complex with the humate. PAA and PVA hardly formed interpolymer complexes with humate due to electrostatic repulsion. The PEI-humate mixture with a volume ratio of 1:20 (PEI:humate) showed zero zeta potential, and a complexed humate with zero surface charge was formed, resulting in no fouling effects on the AEMs. Accordingly, the desalting ED experiments with PEI showed improved ED performance. Further, black colloids formed in the mixture did not cause the cell resistance to increase. PMID:16256509

  13. Highly conductive side chain block copolymer anion exchange membranes.

    Science.gov (United States)

    Wang, Lizhu; Hickner, Michael A

    2016-06-28

    Block copolymers based on poly(styrene) having pendent trimethyl styrenylbutyl ammonium (with four carbon ring-ionic group alkyl linkers) or benzyltrimethyl ammonium groups with a methylene bridge between the ring and ionic group were synthesized by reversible addition-fragmentation radical (RAFT) polymerization as anion exchange membranes (AEMs). The C4 side chain polymer showed a 17% increase in Cl(-) conductivity of 33.7 mS cm(-1) compared to the benzyltrimethyl ammonium sample (28.9 mS cm(-1)) under the same conditions (IEC = 3.20 meq. g(-1), hydration number, λ = ∼7.0, cast from DMF/1-propanol (v/v = 3 : 1), relative humidity = 95%). As confirmed by small angle X-ray scattering (SAXS), the side chain block copolymers with tethered ammonium cations showed well-defined lamellar morphologies and a significant reduction in interdomain spacing compared to benzyltrimethyl ammonium containing block copolymers. The chemical stabilities of the block copolymers were evaluated under severe, accelerated conditions, and degradation was observed by (1)H NMR. The block copolymer with C4 side chain trimethyl styrenylbutyl ammonium motifs displayed slightly improved stability compared to that of a benzyltrimethyl ammonium-based AEM at 80 °C in 1 M NaOD aqueous solution for 30 days. PMID:27216558

  14. Ionic Resistance and Permselectivity Tradeoffs in Anion Exchange Membranes

    KAUST Repository

    Geise, Geoffrey M.

    2013-10-23

    Salinity gradient energy technologies, such as reverse electrodialysis (RED) and capacitive mixing based on Donnan potential (Capmix CDP), could help address the global need for noncarbon-based energy. Anion exchange membranes (AEMs) are a key component in these systems, and improved AEMs are needed in order to optimize and extend salinity gradient energy technologies. We measured ionic resistance and permselectivity properties of quaternary ammonium-functionalized AEMs based on poly(sulfone) and poly(phenylene oxide) polymer backbones and developed structure-property relationships between the transport properties and the water content and fixed charge concentration of the membranes. Ion transport and ion exclusion properties depend on the volume fraction of water in the polymer membrane, and the chemical nature of the polymer itself can influence fine-tuning of the transport properties to obtain membranes with other useful properties, such as chemical and dimensional stability. The ionic resistance of the AEMs considered in this study decreased by more than 3 orders of magnitude (i.e., from 3900 to 1.6 Ω m) and the permselectivity decreased by 6% (i.e., from 0.91 to 0.85) as the volume fraction of water in the polymer was varied by a factor of 3.8 (i.e., from 0.1 to 0.38). Water content was used to rationalize a tradeoff relationship between the permselectivity and ionic resistance of these AEMs whereby polymers with higher water content tend to have lower ionic resistance and lower permselectivity. The correlation of ion transport properties with water volume fraction and fixed charge concentration is discussed with emphasis on the importance of considering water volume fraction when interpreting ion transport data. © 2013 American Chemical Society.

  15. Anion exchange resin as support for invertase immobilization

    Directory of Open Access Journals (Sweden)

    M. Vitolo

    2009-01-01

    Full Text Available

    The invertase (EC 3.2.1.26 from Saccharomyces cerevisiae was employed as a model enzyme in the evaluation of the adsorption capacity of DOWEX-1X8-50®, a basic anion exchange resin, when used as support in enzyme immobilization. By mixing 100mg of resin with 27mg of invertase (pI = 4.0 in buffer solution (pH 4.6, 25°C, stirred at 100rpm, an adsorption of 93% was achieved. The activities (1U = amount of enzyme forming 1mg reducing sugars/min of soluble and insoluble invertase were 0.084 U/mgE and 0.075 U/mgE, respectively, giving an immobilization coefficient of 90.4%. The immobilized invertase had a higher thermal stability than the soluble form. The highest activity was observed at pH 4.5 in both forms of the enzyme, whereas the pH stability ranges for soluble and insoluble invertase were 3.5-5.0 and 4.5-5.5, respectively. The kinetic constants for soluble invertase were KM = 18.3 mM and Vmax = 0.084 U/mgE, and for the insoluble form, KM = 29.1 mM and Vmax = 0.075 U/mgE. The resin tested adsorbed the invertase very well, provided the enzyme molecule had a net negative charge, i.e., the immobilization and reaction procedures had to be carried out at pH > pI. Keywords: Invertase, immobilization, adsorption, anionexchange resin.

  16. Determination of polysaccharide content in Haemophilus influenzae type b conjugate vaccines by high performance anion exchange chromatography-pulsed amperometric detector%高效阴离子交换色谱-脉冲安培法测定b型流感嗜血杆菌结合疫苗的多糖含量

    Institute of Scientific and Technical Information of China (English)

    贺鹏飞; 唐静; 李亚南; 李茂光; 叶强

    2013-01-01

    Objective To determine the polyribosylribitol phosphate (PRP) content in Haemophilus influenzae type b conjugate vaccine by high performance anion exchange chromatography-pulsed amperometric detector (HPAEC-PAD).Methods The PRP in test samples of Hib conjugate vaccine or isolated free polysaccharide was hydrolyzed with 0.3 mol/L sodium hydroxide at room temperature in oscillation for (16 ± 8) h,then separated by CarboPac(@) PA-10 anion exchange column,eluted by sodium hydroxide/sodium acetate gradient elution,detected by pulsed amperometric detector,and calculated according to the peak area of test samples.The samples were tested for 2 times,and the relative standard deviation (RSD) of test results was calculated.Meanwhile,the PRP content in test sample or free PRP content of the same batch of vaccine were determined by orcinol method in the appendix of Chinese Pharmacopoeia (Volume Ⅲ,2010 edition),and the result was compared with that by HPAEC-PAD.Results The RSD between 2 test results of the same sample was not more than 4.6%.The total PRP contents in samples S01~S03 determined by HPAEC-PAD were 105%,104% and 106%,while the free PRP contents were 126%,109% and 115% of those by orcinol method,respectively.Conclusion HPAEC-PAD method showed high sensitivity,reproducibility and separation effectiveness for PRP content in Hib conjugate vaccine,by which the samples needed no derivation,and multiple components were determined at the same time,therefore may be used as an alternative method of traditional orcinol method for deter-mination of PRP content in Hib conjugate vaccine.%目的 采用高效阴离子交换色谱-脉冲安培检测法(high performance anion exchange chromatography withpulsed amperometric detector,HPAEC-PAD)测定b型流感嗜血杆菌(haemophilus influenzae type b,Hib)结合疫苗的多聚磷酸核糖基核糖醇(polyribosylribitol phosphate,PRP)多糖含量.方法 用终浓度为0.3N的NaOH溶液将待测疫苗中的PRP多糖

  17. Nanostructure-controlled anion exchange membranes for fuel cell applications by high-energy heavy-ion irradiation. Preparation and characterization of anion exchange membranes

    International Nuclear Information System (INIS)

    Heavy ions at kinetic energies typically from several hundreds of MeV to a few GeV passing through a polymer substrate induce a continuous trail of excitations and ionizations called latent tracks. We used a direct ion-track grafting method for preparation of anion exchange membranes for fuel cells. The functional anion exchange groups were introduced inside the latent tracks, thereby achieving OH--conductive channels through the thickness. These straight channels increased conductivities, while the isolated cylindrical structure of tracks restricted the water uptake. (author)

  18. Preparation of a chitosan-based anionic exchanger for removal of bromide, chloride, iodide and phosphate ions from aqueous solutions

    Directory of Open Access Journals (Sweden)

    Affonso Celso Gonçalves Júnior

    2014-02-01

    Full Text Available The development of a chitosan anion exchanger, obtained from shrimp shells, and its adsorption capacity for chloride, bromide, iodide and phosphate anions are provided. Dependence of exchange processes with the anions as a function of pH and contact time between exchanger and anions were initially investigated. Results showed that the best adsorption of ions occurred at pH 3.0. Exchange isotherms were then developed by the Langmuir, Freundlich and Dubinin-Radushkevich mathematical models. Results demonstrated that chitosan produced from shrimp shells may be used as feedstock in the manufacture of anion exchange microspheres.

  19. Tools to discover anionic and nonionic polyfluorinated alkyl surfactants by liquid chromatography electrospray ionisation mass spectrometry

    DEFF Research Database (Denmark)

    Trier, Xenia; Granby, Kit; Christensen, Jan H.

    2011-01-01

    A tiered approach is proposed for the discovery of unknown anionic and nonionic polyfluorinated alkyl surfactants (PFASs) by reversed phase ultra high performance liquid chromatography (UHPLC) – negative electrospray ionisation – quadrupole time of flight mass spectrometry (UHPLC–ESI−–QTOF–MS). T.......g., structural PFAS isomers. The method has been used to discover PFASs in industrial blends and in extracts from food contact materials....

  20. Removal of plutonium from nitric acid-oxalic acid solutions using anion exchange method

    International Nuclear Information System (INIS)

    An anion exchange method using Amberlyst A-26 (MP) resin was developed for removal of Pu from nitric acid-oxalic acid solutions without destroying oxalate. The method consists of sorption of Pu(IV) on Amberlyst A-26, a macroporous anion exchange resin, from nitric acid-oxalic acid medium in the presence of Al(NO3)3. Pu(IV) breakthrough capacity of Amberlyst A-26 using synthetic feed solution was determined. (author)

  1. Anion-Exchange Properties of Trifluoroacetate and Triflate Salts of N-Alkylammonium Resorcinarenes.

    Science.gov (United States)

    Pan, Fangfang; Beyeh, Ngong Kodiah; Bertella, Stefania; Rissanen, Kari

    2016-03-01

    The synthesis of N-benzyl- and N-cyclohexylammonium resorcinarene trifluoroacetate (TFA) and triflate (OTf) salt receptors was investigated. Solid-state analysis by single-crystal X-ray diffraction revealed that the N-alkylammonium resorcinarene salts (NARSs) with different upper substituents had different cavity sizes and different affinities for anions. Anion-exchange experiments by mixing equimolar amounts of N-benzylammonium resorcinarene trifluoroacetate and N-cyclohexylammonium resorcinarene triflate, as well as N-benzylammonium resorcinarene triflate and N-cyclohexylammonium resorcinarene trifluoroacetate showed that the NARS with flexible benzyl groups preferred the larger OTf anion, whereas the rigid cyclohexyl groups preferred the smaller TFA anions. The anion-exchange processes were confirmed in the solid state by single-crystal and powder X-ray diffraction experiments and in the gas phase by electrospray ionization mass spectrometry. PMID:26749383

  2. A simple ion chromatography method for inorganic anion analysis in edible seaweeds.

    Science.gov (United States)

    Gómez-Ordóñez, Eva; Alonso, Esther; Rupérez, Pilar

    2010-09-15

    A new, simple, fast and sensitive ion chromatography (IC) method, for the simultaneous analysis of fluoride, chloride, nitrite, bromide, nitrate, phosphate and sulphate in edible seaweeds was developed and reported for the first time. The validation of the analytical method was studied in terms of linearity, sensitivity, precision and accuracy. All standard calibration curves showed very good correlation between anion peak area and concentration (r>0.999). Limits of detection and quantitation ranged between 0.002-0.05 mg/L and 0.01-0.1mg/L, respectively and indicated the high sensitivity of the method. Relative standard deviation values of repeatability and inter-day precision for standard anions with the same sample were less than 2%. Anion recoveries ranged from 97 to 113% for chloride and from 87 to 105% for sulphate, respectively and showed the fairly good accuracy of the method. The method was applied to the analysis of inorganic anions in brown and red edible seaweeds. Brown seaweeds were characterized by higher chloride content up to 33.7-36.9%, while red seaweeds were characterized by higher sulphate content (45-57%). Sulphate content in seaweeds is related to the presence of sulphated polysaccharides of biological importance. The method developed was well applicable to mineral anion analysis in edible seaweeds and shows suitability and reliability of use in other food samples of nutritional importance. PMID:20801334

  3. [Determination of inorganic anions and gluconate by two-dimensional ion chromatography].

    Science.gov (United States)

    Chen, Ailian; Ding, Hui; Fang, Linmei; Shi, Chaoou

    2015-12-01

    A new two-dimensional ion chromatography method was developed to parallelly analyze two different types of samples with the application of valve switching technology-suppressed conductivity and pulsed amperometric analysis system, for concurrent determination of chloride, nitrite, sulfate, nitrate four inorganic anions and gluconate. The first dimensional chromatography was using Ionpac AG18+Ionpac AS18 anion analysis columns with a suppressed conductivity detector for the separation and detection of Cl-, NO2-, SO4(2-) and NO3-. Respectively, the elution was 5 and 20 mmol/L NaOH at an isocratic flow rate of 1.0 mL/min and sample injection volume of 25 μL. The second dimensional chromatography was utilizing two guard columns, CarboPac PA1 and CarboPac PA20, with 90 mmol/L NaOH solution for the isocratic eluent of 0.8 mL/min. Gluconate was enriched by an AG15 column and switched into the pulsed amperometric detector. The results showed that: each inorganic anion in 0. 1-5.0 mg/L and gluconate in 0.085 6-4.282 5 mg/L had a good linear relationship (R2 ≥ 0.994 5). The RSDs of the peak areas were between 1.05%-1.94%. The limits of detection were 0.61-2.17 μg/L for the anions and 24.24 μg/L for the gluconate. The recoveries were between 90.3% - 102.8%. The two detection modes parallelly have good separation efficiency, detection accuracy and the precision of the separation and are suitable for the analysis of complex samples. PMID:27097469

  4. Anion exchange sorption of molybdate and germanate from salt solutions

    Energy Technology Data Exchange (ETDEWEB)

    Kislinskaya, G.E.; Denisova, T.I.; Sheka, I.A. (AN Ukrainskoj SSR, Kiev. Inst. Obshchej i Neorganicheskoj Khimii)

    1983-02-01

    A study has been made of the state of Mo(6) and Ge(4) in solutions containing various concentrations (5-300 g/l) of HCl and their sorption with highly-alkaline macroporous anionites (Duolite 101 D, ChFO, AM, AMP) and hydroxides of iron and aluminium, depending on pH value, element concentration and time of solution contact with sorbent. Polymer anions of molybdate with a sorption maximum at pH=1-3 and monomer anions of germanate at pH>8 are found to be the most active forms of molybdenum and germanium, as to their sorption, at their concentrations of 10/sup -6/-10/sup -5/g-atom/l in sodium chloride solutions. Regions of molybdate and germanate effective sorption with anionites and hydroxides of iron and aluminium in electrolyte solutions get narrower, as compared with aqueous solutions, due to competing sorption of a background electrolyte anion.

  5. Denatured Thermodynamics of Proteins in Weak Cation-exchange Chromatography

    Institute of Scientific and Technical Information of China (English)

    LI Rong; CHEN Guo-Liang

    2003-01-01

    The thermostability of some proteins in weak cation-exchange chromatography was investigated at 20-80 ℃. The results show that there is a fixed thermal denaturation transition temperature for each protein. The appearance of the thermal transition temperature indicates that the conformations of the proteins are destroyed seriously. The thermal behavior of the proteins in weak cation-exchange and hydrophobic interaction chromatographies were compared in a wide temperature range. It was found that the proteins have a higher thermostability in a weak cation-exchange chromatography system. The thermodynamic parameters(ΔH0, ΔS0) of those proteins were determined by means of Vant Hoff relationship(lnk-1/T). According to standard entropy change(ΔS0), the conformational change of the proteins was judged in the chromatographic process. The linear relationships between ΔH0 and ΔS0 can be used to evaluate "compensation temperature"(β) at the protein denaturation and identify the identity of the protein retention mechanism in weak cation-exchange chromatography.

  6. Preparation of high-capacity, weak anion-exchange membranes by surface-initiated atom transfer radical polymerization of poly(glycidyl methacrylate) and subsequent derivatization with diethylamine

    Science.gov (United States)

    Qian, Xiaolei; Fan, Hua; Wang, Chaozhan; Wei, Yinmao

    2013-04-01

    Ion-exchange membrane is of importance for the development of membrane chromatography. In this work, a high-capacity anion-exchange membrane was prepared by grafting of glycidyl methacrylate (GMA) onto the surface of regenerated cellulose (RC) membranes via surface-initiated atom transfer radical polymerization (SI-ATRP) and subsequent derivatization with diethylamine. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to characterize changes in the chemical functionality, surface topography and pore morphology of the modified membranes. The static capacity of the prepared anion-exchange membrane was evaluated with bovine serum albumin (BSA) as a model protein. The results indicated that the anion-exchange membrane which could reach a maximum capacity of 96 mg/mL for static adsorption possesses a higher adsorption capacity, and the adsorption capacity increases with the polymerization time. The effect of pH and salt concentration confirmed that the adsorption of BSA followed ion-exchange mechanism. The established method would have potential application in the preparation of anion-exchange membrane.

  7. Absence of transepithelial anion exchange by rabbit OMCD: Evidence against reversal of cell polarity

    International Nuclear Information System (INIS)

    In the rabbit cortical collecting duct (CCD), Cl tracer crosses the epithelium predominantly via an anion exchange system that operates in either a Cl-Cl or Cl-HCO3 exchange mode. In the present study, the authors used the 36Cl lumen-to-bath rate coefficient (KCl, nm/s), a sensitive measurement of CCD transepithelial anion transport, to investigate the nature of Cl transport in the medullary collecting duct dissected from inner stripe, outer medulla (OMCD). The KCl in OMCD perfused and bathed in HCO3-Ringer solution was low and similar to that value observed in the CCD when anion exchange is inhibited and Cl permeates the epithelium by diffusion. To test the hypothesis that metabolic alkalosis could reverse the polarity of intercalated cells and thus induce an apical Cl-HCO3 exchanger in H+-secreting OMCD cells, they measured KCl in OMCD from rabbits make alkalotic by deoxycorticosterone and furosemide. Although the base-line KCl was slightly higher than in OMCD from control rabbits, the value was still far lower than the KCl under comparable conditions in CCD. They conclude (1) Cl transport across the MCD by anion exchange is immeasurably low or nonexistent; (2) unlike the CCD, Cl transport in OMCD is not responsive to cAMP; and (3) metabolic alkalosis does not induce an apical anion exchanger in OMCD, i.e., does not cause epithelial polarity reversal

  8. Grafting glycidyl methacrylate to Sepharose gel for fabricating high-capacity protein anion exchangers.

    Science.gov (United States)

    Wang, Qianqian; Yu, Linling; Sun, Yan

    2016-04-22

    To develop ion exchangers of high protein adsorption capacity, we have herein introduced atom transfer radical polymerization (ATRP) method to graft glycidyl methacrylate (GMA) onto Sepharose FF gel. GMA-grafted Sepharose FF resins of four grafting densities and different grafting chain lengths were obtained by adjusting reaction conditions. The epoxy groups on the grafted chains were functionalized by modification with diethylamine (DEA), leading to the fabrication of Sepharose-based anion exchangers of 14 different grafting densities and/or grafting chain lengths. The resins were first characterized for the effects of grafting density, chain length and ionic strength on pore sizes by inverse size exclusion chromatography. Then, the resins were evaluated by adsorption equilibria of bovine serum albumin (BSA) as a function of ionic capacity (IC) (chain length) at individual grafting densities. It was observed that at each grafting density there was a specific IC value (chain length) that offered the maximum equilibrium capacity. Of the resins with maximum values at individual grafting densities, the resin of the second grafting density with an IC value of 330 mmol/L (denoted as FF-Br2-pG-D330) showed the highest capacity, 264 mg/mL, about two times higher than that of the traditional ungrafted resin Q Sepharose FF (137 mg/mL). This resin also showed the most favorable uptake kinetics among the resins of similar IC values but different grafting densities, or of the same grafting density but different IC values. Effects of ionic strength showed that the capacities of FF-Br2-pG-D330 were much higher than Q Sepharose FF at a wide range of NaCl concentrations (0-200 mmol/L), and the uptake rates of the two resins were similar in the ionic strength range. Therefore, the dynamic binding capacity values of BSA on FF-Br2-pG-D330 were much higher than Q Sepharose FF as demonstrated at different residence times and ionic strengths. Taken together, the research has proved the

  9. Fundamental study of practical separation of boron isotopes by means of anion exchange resin, (2)

    International Nuclear Information System (INIS)

    As we reported earlier, a boric acid band formed in a column of weak base anion exchange resin Diaion WA21 can be eluted with pure water, resulting in good isotope fractionation. In the present research, we carried out various experiments using this process in order to find the necessary conditions for producing a displacement chromatogram at the end of the boric acid band, where 10B is enriched. Suitable conditions were found to be as follows: the concentration of boric acid was 0.1 mol/l, the operating temperature was 400C and the flow rate was 20 ml/hr.cm2. Under these conditions, four experimental runs having different migration lengths (1, 2, 4, 8 m) were carried out by a new method which we named ''Isotopic Plateau Holding Displacement Chromatography''. In these experiments, the enriched part of band was always preceded by the isotopic plateau part, in which the atomic fraction of 10B was maintained at its original value. The results of these experiments carried out by this method showed that the concentration of 10B at the end of the chromatogram increased with the migration length, and in the case of 8 m migration, 10B was enriched from an original value of 19.84 to 33.26%. The separation factor S was found to be constant, 1.0097+-0.0002, irrespective of migration length. (auth.)

  10. Significance of anion exchange in pentachlorophenol sorption by variable-charge soils.

    Science.gov (United States)

    Hyun, Seunghun; Lee, Linda S; Rao, P Suresh C

    2003-01-01

    Sorption data and subsequent predictive models for evaluating acidic pesticide behavior on variable-charge soils are needed to improve pesticide management and environmental stewardship. Previous work demonstrated that sorption of pentachlorophenol (PCP), a model organic acid, was adequately modeled by accounting for pH-and pKa-dependent chemical speciation and using two organic carbon-normalized sorption coefficients; one each for the neutral and anionic species. Such models do not account for organic anion interaction to positively charged surface sites, which can be significant for variable-charge minerals present in weathered soils typical of tropical and subtropical regions. The role of anion exchange in sorption of ionizable chemicals by variable-charge soils was assessed by measuring sorption of PCP by several variable-charge soils from aqueous solutions of CaCl2, CaSO4, Ca(H2PO4)2 as a function of pH. Differences in sorption from phosphate and chloride electrolyte solutions were attributed to pentachlorophenolate interactions with anion exchange sites. Suppression of PCP sorption by phosphate ranged from negligible in a soil with essentially no positively charge sites, as measured by negligible anion exchange capacity, to as much as 69% for variable-charge soils. Pentachlorophenolate exchange correlated well with the ratio of pH-dependent anion exchange capacity to net surface charge. Sorption reversibility of PCP by both CaCl2 and Ca(H2PO4)2 solutions was also demonstrated. Results for PCP clearly demonstrate that sorption to anion exchange sites in variable-charge soils should be considered in assessing pesticide mobility and that phosphate fertilizer application may increase the mobility of acidic pesticides. PMID:12809297

  11. Models for the estimation of thermodynamic properties of layered double hydroxides: application to the study of their anion exchange characteristics

    Directory of Open Access Journals (Sweden)

    Bravo-Suárez Juan J.

    2004-01-01

    Full Text Available Several models for the estimation of thermodynamic properties of layered double hydroxides (LDHs are presented. The predicted thermodynamic quantities calculated by the proposed models agree with experimental thermodynamic data. A thermodynamic study of the anion exchange process on LDHs is also made using the described models. Tables for the prediction of monovalent anion exchange selectivities on LDHs are provided. Reasonable agreement is found between the predicted and the experimental monovalent anion exchange selectivities.

  12. Anions Analysis in Ground and Tap Waters by Sequential Chemical and CO2-Suppressed Ion Chromatography

    Directory of Open Access Journals (Sweden)

    Glen Andrew D. De Vera

    2011-06-01

    Full Text Available An ion chromatographic method using conductivity detection with sequential chemical and CO2 suppression was optimized for the simultaneous determination of fluoride, chloride, bromide, nitrate,phosphate and sulfate in ground and tap water. The separation was done using an anion exchange column with an eluent of 3.2 mM Na2CO3 and 3.2 mM NaHCO3 mixture. The method was linear in the concentration range of 5 to 300 μg/L with correlation coefficients greater than 0.99 for the six inorganic anions. The method was also shown to be applicable in trace anions analysis as given by the low method detection limits (MDL. The MDL was 1μg/L for both fluoride and chloride. Bromide, nitrate, phosphate and sulfate had MDLs of 7 μg/L, 10 μg/L, 9 μg/L and 2 μg/L, respectively. Good precision was obtained as shown in the relative standard deviation of 0.1 to 12% for peak area and 0.1 to 0.3% for retention time. The sensitivity of the method improved with the addition of CO2 suppressor to chemical suppression as shown in the lower background conductivity and detection limits. The recoveries of the anions spiked in water at 300 μg/L level ranged from 100 to 104%. The method was demonstrated to be sensitive, accurate and precise for trace analysis of the six anions and was applied in the anions analysis in ground and tap waters in Malolos, Bulacan. The water samples were found to contain high concentrations of chloride of up to 476 mg/L followed by sulfate (38 mg/L, bromide (1 mg/L, phosphate (0.4 mg/L, fluoride (0.2 mg/L and nitrate (0.1 mg/L.

  13. Separation of metal ions by anion exchange in mixtures of hydrochloric acid and hydrofluoric acid

    Energy Technology Data Exchange (ETDEWEB)

    Faris, J.P.

    1978-12-01

    Distribution coefficients were determined for the adsorption of more than 40 elements on anion-exchange resins from mixtures of HCl (0.1 to 12M) and HF (0.1-8M). Two resins, Dowex 1 x 10, 200 to 400 mesh and Dowex 1 x 4, 100 to 200 mesh, were used. Distribution coefficients were also determined for the adsorption of many elements on both resins from 0.1 to 12M HCl and 0.1 to 12M HF. Anion exchange in the presence of HF was found useful for separating impurities from various materials for their subsequent determination, and specific procedures used in our spectrochemical laboratory for this purpose are outlined. The results of a literature search on the use of anion exchange in hydrofluoric acid and fluoride-containing media are presented in an extensive bibliography. 404 references, 9 tables.

  14. Separation of metal ions by anion exchange in mixtures of hydrochloric acid and hydrofluoric acid

    International Nuclear Information System (INIS)

    Distribution coefficients were determined for the adsorption of more than 40 elements on anion-exchange resins from mixtures of HCl (0.1 to 12M) and HF (0.1-8M). Two resins, Dowex 1 x 10, 200 to 400 mesh and Dowex 1 x 4, 100 to 200 mesh, were used. Distribution coefficients were also determined for the adsorption of many elements on both resins from 0.1 to 12M HCl and 0.1 to 12M HF. Anion exchange in the presence of HF was found useful for separating impurities from various materials for their subsequent determination, and specific procedures used in our spectrochemical laboratory for this purpose are outlined. The results of a literature search on the use of anion exchange in hydrofluoric acid and fluoride-containing media are presented in an extensive bibliography. 404 references, 9 tables

  15. Nanocomposite membranes based on quaternized polysulfone and functionalized montmorillonite for anion-exchange membranes

    Science.gov (United States)

    Liao, Xiaofeng; Ren, Li; Chen, Dongzhi; Liu, Xiaohong; Zhang, Hongwei

    2015-07-01

    In this paper, functionalized montmorillonite is intercalated with cetyl trimethyl ammonium chloride and (3-aminopropyl)triethoxysilane. Quaternized polysulfone/functionalized montmorillonite nanocomposite membranes are fabricated to evaluate their potential in anion-exchange membrane fuel cells. Fourier transform infrared spectroscopy, thermogravimetric analyzer and X-ray diffractometer are used to confirm the success of intercalation. The performances of the composite membranes for the anion-exchange membrane fuel cells in terms of their water uptake, mechanical property and ionic conductivity are investigated. Compared with other anion-exchange membranes, the nanocomposite membrane containing 5% montmorillonite modified by cetyl trimethyl ammonium chloride exhibits lower water uptake, higher ultimate stress and larger ionic conductivity. It exhibits an ionic conductivity of 4.73 × 10-2 S cm-1 at 95 °C.

  16. Anion-exchange Studies of Radioactive Trace Elements in Sulphuric Acid Solutions

    International Nuclear Information System (INIS)

    As part of a chemical group separation procedure used as a pretreatment in gamma spectrometric analysis, a study has been made of the adsorption from sulphuric acid solutions on strongly basic anion exchange resins, prepared in the hydroxide and the sulphate forms, of trace activities of Na, P, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Rb, Sr, Zr, Nb, Mo, Tc, Ag, Cd, In, Cs, Ba, La, Ce, Hf, Ta, W, Ir, Pa and Np. Besides adsorbing some of the trace elements in the solution, the anion exchange resin in the hydroxide form will neutralize the bulk of the sulphuric acid. This makes possible the subsequent sequential separation of chloride complexes on short anion-exchange columns by a stepwise increasing of the HCl concentration of the solution. On the basis of the results obtained in the present and earlier experiments, a new improved chemical group-separation procedure for mixtures of radioactive trace elements is outlined

  17. The influence of salt type on the retention of bovine serum albumin in ion-exchange chromatography

    DEFF Research Database (Denmark)

    Al-Jibbouri, Sattar

    2007-01-01

    In this paper, an analysis of the influence of the salt types, NaCl, NaCH"3COO, Na"2SO"4 and Na"3C"6H"5O"7, on the isocratic retention behaviour of bovine serum albumin (BSA) on two anion-exchangers media (Source 30Q and TSK Gel Super Q 5 PW) has been presented. The retention data demonstrated that...... the mechanism of protein retention in ion-exchange chromatography (IEC) involves interactions between the protein solute, the mobile phase constituents and the stationary phase. The effect of protein activity coefficient in the mobile phase on the protein retention volumes is verified....

  18. Simultaneous Analysis of Monovalent Anions and Cations with a Sub-Microliter Dead-Volume Flow-Through Potentiometric Detector for Ion Chromatography.

    Science.gov (United States)

    Dumanli, Rukiye; Attar, Azade; Erci, Vildan; Isildak, Ibrahim

    2016-04-01

    A microliter dead-volume flow-through cell as a potentiometric detector is described in this article for sensitive, selective and simultaneous detection of common monovalent anions and cations in single column ion chromatography for the first time. The detection cell consisted of less selective anion- and cation-selective composite membrane electrodes together with a solid-state composite matrix reference electrode. The simultaneous separation and sensitive detection of sodium (Na(+)), potassium (K(+)), ammonium (NH4 (+)), chloride (Cl(-)) and nitrate (NO3 (-)) in a single run was achieved by using 98% 1.5 mM MgSO4 and 2% acetonitrile eluent with a mixed-bed ion-exchange separation column without suppressor column system. The separation and simultaneous detection of the anions and cations were completed in 6 min at the eluent flow-rate of 0.8 mL/min. Detection limits, at S/N = 3, were ranged from 0.2 to 1.0 µM for the anions and 0.3 to 3.0 µM for the cations, respectively. The developed method was successfully applied to the simultaneous determination of monovalent anions and cations in several environmental and biological samples. PMID:26786906

  19. Modified anion-exchange method for determination of thorium in uranium based materials

    International Nuclear Information System (INIS)

    This paper details a modified anion-exchange method for estimation of thorium in uranium based samples like uranium dioxide powders, pellets and uranyl nitrate solutions. The method involves separation of thorium from uranium from 3M commercial grade HCl containing 15% NaCl through an anion-exchange resin. The uranium free effluent containing the analyte(thorium) is determined spectrophotometrically by exploiting absorption of the thorium-arsenazo III complex at 660 nm. The method has a precision of about ±2% at 50 ppm level. (author). 3 refs., 1 tab

  20. Impact of powdered activated carbon and anion exchange resin on photocatalytic treatment of textile wastewater

    OpenAIRE

    Dhas, Preethi Grace Theva Neethi; Gulyas, Holger; Otterpohl, Ralf

    2015-01-01

    In order to clarify the impact of activated carbon and anion exchange resin on photocatalytic oxidation (PCO) of textile industry wastewater, TiO2-based PCO was investigated with aqueous solutions containing the reactive dye Reactive Blue 4 (RB4) and with a textile dye house effluent in the absence and in the presence of powdered activated carbon (PAC) and the anion exchange resin Lewatit MP 500. Addition of Lewatit improved RB4 removal to a larger extent than PAC addition. Contrasting to chl...

  1. Simultaneous analysis of trehalose,glucose and maltose in biotransformation samples by high performance anion exchange chromatography with pulsed ampere detection%高效阴离子交换色谱-脉冲安培检测法同时测定生物转化样品中的海藻糖、葡萄糖和麦芽糖

    Institute of Scientific and Technical Information of China (English)

    徐颖; 臧颖; 姜婷; 郑兆娟; 欧阳嘉

    2014-01-01

    An analytical method for the determination of trehalose,maltose,and glucose in biotransformation samples was developed by using high performance anion exchange chroma-tography coupled with pulsed ampere detection( HPAEC-PAD). The analysis was performed on a CarboPacTM 10 column( 250 mm × 2 mm ) with the gradient elution of NaOH-NaAc as the mobile phase. The column temperature was set at 30 ℃,the flow rate was 0. 30 mL/min. The results showed that trehalose,maltose,and glucose in biotransformation system were com-pletely separated and determined in 15 min. The linear ranges and the working curves were determined by using standard samples. The correlation coefficients of three kinds of carbohy-drates were over 0. 999 8 . The detection limits( LODs)were 0. 010-0. 100 mg/L. Under the optimized separation conditions,the recoveries of saccharides in the transformation system at three different spiked levels ranged from 89. 4% to 103. 2%. In biotransformation system,50 IU trehalose synthase were added into 200 g/L maltose for reaction of 8 h at 37 ℃,pH 8. 0. Under the above conditions,the concentration of trehalose in biotransformation sample was 101. 084 g/L,and the conversion rate of trehalose reached 50. 5%. The method can be applied to deter-mine the composition in the transformation system with the advantages of simplicity and con-venience.%建立了高效阴离子交换色谱-脉冲安培电化学检测法同时测定生物转化样品中海藻糖、葡萄糖和麦芽糖的分析方法。选用 CarboPacTM10色谱柱(250 mm×2 mm)对分离条件进行优化,使用标准样品测定了线性范围和工作曲线,柱温为30℃,流速为0.30 mL/min,以氢氧化钠溶液和醋酸钠溶液为流动相进行梯度洗脱,脉冲安培法进行检测。研究结果表明,该方法可在15 min内实现海藻糖生物转化液中3种糖的快速定量分析。海藻糖、葡萄糖和麦芽糖峰面积与质量浓度的线性关系良好,检出限为0

  2. Anion exchange pathways for Cl- transport in rabbit renal microvillus membranes

    International Nuclear Information System (INIS)

    The authors evaluated the mechanisms of chloride transport in microvillus membrane vesicles isolated from the rabbit renal cortex. The presence of Cl-formate exchange was confirmed. Outward gradients of oxaloacetate, HCO3, acetate, lactate, succinate, sulfate, and p-aminohippurate (PAH) stimulated the rate of Cl uptake minimally or not at all. However, an outward gradient of oxalate stimulated Cl uptake by 70%, and an outward Cl gradient induced uphill oxalate uptake, indicting Cl-oxalate exchange. Moreover, an outward formate gradient induced uphill oxalate uptake, indicating formate-oxalate exchange. Studies of inhibitor and substrate specificity indicated the probably operation of at least two separate anion exchangers in mediating Cl transport. The Cl-formate exchanger accepted Cl and formate as substrates, had little or no affinity for oxalate, was sensitive to inhibition by furosemide, and was less sensitive to inhibition by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). The Cl (formate)-oxalate exchanger also accepted Cl and formate as substrates but had high affinity for oxalate, was highly sensitive to inhibition by DIDS, and was less sensitive to inhibition by furosemide. The Cl-formate exchanger was electroneutral, whereas the Cl (formate)-oxalate exchanger was electrogenic. They conclude that at least separate anion exchangers mediating Cl transport are present on the luminal membrane of the rabbit proximal tubule cell. These exchangers may play important roles in mediating transtubular Cl and oxalate transport in this nephron segment

  3. Effect of alcohols on separation behavior of rare earth elements using benzimidazole-type anion-exchange resin in nitric acid solutions

    International Nuclear Information System (INIS)

    The mutual separation of rare earth elements based on the ion exchange chromatography has been studied. The effect of alcohols on separation behavior of rare earth elements using the benzimidazole-type anion-exchange resin embedded in high-porous silica beads was investigated in nitric acid/alcohol mixed solvent systems. It was confirmed that the mutual separation of rare earth elements is possible by using our proposed methods. It was found that the distribution coefficients of rare earth elements depend on the corresponding alcoholic relative permittivity and on the steric hindrance due to the hydrophobic interaction among each alcoholic molecule. (author)

  4. Direct determination of seleno-amino acids in biological tissues by anion-exchange separation and electrochemical detection.

    Science.gov (United States)

    Cavalli, S; Cardellicchio, N

    1995-07-01

    Several studies have described the determination of selenium in protein extracts from tissues of marine or terrestrial animals, but have not identified the different chemical forms of selenium that are present. Selenium may be present as seleno-amino acids. Selenocysteine, for example, is a normal component of glutathione peroxidase, an antioxidant enzyme which may behave like other antioxidants, such as vitamin E, protecting tissues against methylmercury toxicity. The present study illustrates a method for the characterization of seleno-amino acids, such as selenocysteine and selenomethionine, in proteins extracted from the liver of marine mammals. The mechanism of detoxification of methylmercury, which involves seleno-compounds, is identified. The analytical determination was carried out using high-performance anion-exchange chromatography coupled with integrated pulsed amperometric detection (HPAEC-IPAD). This method allows the direct determination of underivatized amino acids, eliminating the procedure of pre- or postcolumn derivatization. The chromatographic separation was carried out on an anion-exchange column using a quaternary gradient elution. In order to optimize this method, interferences of amino acids and the influence of pH and ionic strength on the separation and electrochemical detection were studied. The IPAD response for the direct detection of amino acids is optimum at pH > 11. The detection limit (S/N = 3) for selenocysteine was found to be 450 micrograms/l. The application of this method for the identification of seleno-amino acids in protein hydrolysates is also shown. PMID:7640774

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

    Institute of Scientific and Technical Information of China (English)

    赵璇; 何仕均; 杨磊

    2002-01-01

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

  6. New anion-exchange resins for improved separations of nuclear materials. Mid-year progress report

    International Nuclear Information System (INIS)

    'The authors are developing multi-functional anion-exchange resins that facilitate anion uptake by carefully controlling the structure of the anion receptor site. The new ion-exchange resins interface the rapidly developing field of ion-specific chelating ligands with robust, commercial ion exchange technology. The overall objective of the research is to develop a predictive capability which allows the facile design and implementation of multi-functionalized anion exchange materials which selectively sorb metal complexes of interest from targeted process, waste, and environmental streams. The basic scientific issues addressed are actinide complex speciation along with modeling of the metal complex/functional site interactions in order to determine optimal binding-site characteristics. Their approach uses a thorough determination of the chemical species both in solution and as bound to the resin to determine the characteristics of resin active sites which can actively facilitate specific metal-complex sorption to the resin. The first year milestones were designed to allow us to build off of their extensive expertise with plutonium in nitrate solutions prior to investigating other, less familiar systems. While the principle investigators have successfully developed actinide chelators and ion-exchange materials in the past, the authors were fully aware that integration of this two fields would be challenging, rewarding and, at times, highly frustrating. Relatively small differences in the substrate (cross-linkage, impurities), the active sites (percent substitution, physical accessibility), the actinide solution (oxidation state changes, purity) and the analytical procedures (low detection limits) can produce inconsistent sorption behavior which is difficult to interpret. The potential paybacks for success, however, are enormous. They feel that they have learned a great deal about how to control these numerous variables to produce consistent, reliable analysis of

  7. Test procedure for anion exchange testing with Argonne 10-L solutions

    International Nuclear Information System (INIS)

    Four anion exchange resins will be tested to confirm that they will sorb and release plutonium from/to the appropriate solutions in the presence of other cations. Certain cations need to be removed from the test solutions to minimize adverse behavior in other processing equipment. The ion exchange resins will be tested using old laboratory solutions from Argonne National Laboratory; results will be compared to results from other similar processes for application to all plutonium solutions stored in the Plutonium Finishing Plant

  8. Determination of the ion-exchange capacity of anion-selective membranes

    Czech Academy of Sciences Publication Activity Database

    Karas, F.; Hnát, J.; Paidar, M.; Schauer, Jan; Bouzek, K.

    2014-01-01

    Roč. 39, č. 10 (2014), s. 5054-5062. ISSN 0360-3199 Institutional support: RVO:61389013 Keywords : ion-exchange capacity * anion-selective membranes * titration Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.313, year: 2014

  9. Studies concerning the anion ex-change resins catalyzed esterification of epichlorohydrin with organic acids

    Directory of Open Access Journals (Sweden)

    E.I. Muresan

    2009-09-01

    Full Text Available The paper studies the esterification of carboxylic acids with epichlorohydrin over two macroporous strong base anion exchange resins with different polymer matrix. For both resins, the influence of reaction parameters (temperature, catalyst loading, molar ratio on the reaction rate and the yields of the two isomeric esters were investigated.

  10. Investigation of an anion exchange resin for cleanup of a coolant used to machine nuclear materials

    International Nuclear Information System (INIS)

    This article describes the interaction of Dowex SBR-P, which is a strongly basic anion exchange resin, with ions found in a used machining coolant. The coolant is used in machining enriched uranium and contains uranium, chloride, nitrite, borate ions, water, and propylene glycol

  11. Separation of the rare earths by anion-exchange in the presence of lactic acid

    Science.gov (United States)

    Faris, J. P.

    1969-01-01

    Investigation of adsorption of rare earths and a few other elements to an anion-exchange resin from mixed solvents containing lactic acid shows that the lanthanides are absorbed more strongly than from the alpha-hydroxyisobutryric acid system, but with less separation between adjacent members of the series.

  12. Strong basic anion exchangers with adsorption properties for chlorocomplex uranyl ion

    International Nuclear Information System (INIS)

    Full text: Styrene-divinylbenzene copolymers (S-DVB) are still the most commonly used as starting copolymers in the synthesis of ion exchangers with special destinations, such as the enrichment process of 235U due to their high chemical resistance. For this purpose, a special concern has been lately focused on the preparation of macroporous strong basic anion exchangers containing one or two hydroxyalkyl substituents. An average pore radius around 1000 A, which is correlated with a high permanent porosity, a good stability of the resin in HCl with concentrations up to 8 N, a thermal resistance up to 150 deg C at least and a high mechanical strength are the main characteristics requested for this purpose. In a previous work we have reported the preparation of some macroporous S-DVB copolymers with sizes in the range 90-200 μm by employing 2-ethyl-1-hexanol as a porogen, at a high dilution of monomers (D ≥ 0.55) and their subsequent transformation in macroporous strong basic anion exchangers with an average pore radius higher than 50 nm. In the present study, the characteristics of the starting S-DVB macroporous copolymers synthesized in the presence of N-butyl alcohol (nBA) as porogen and those of the strong basic anion exchangers derived therefrom have been studied. Activation by chloromethylation reaction of the macroporous S-DVB copolymers was performed with paraformaldehyde (CH2O)n/trimethylchlorosilane (TMCS) in the presence of FeCl3 as catalyst, in chloroform as a reaction medium. Strong basic anion exchangers with diethyl 2-hydroxyethyl benzylammonium groups were obtained by the amination of the chloromethylated S-DVB copolymers with diethyl 2-hydroxyethylamine (DEHEA). The corresponding strong basic anion exchangers showed an ionic exchange capacity in the range 1.8-2.2 meq/g, depending on the crosslinking degree and the dilution of the starting copolymer, and an average pore radius, rp, around 80 nm. Such characteristics make these resins promising

  13. M8L12 cubic cages with all facial Δ or facial Λ configuration: effects of surface anions on the occupancy of the cage and anion exchange.

    Science.gov (United States)

    Yang, Jing; Chang, Xiao-Yong; Sham, Kiu-Chor; Yiu, Shek-Man; Kwong, Hoi-Lun; Che, Chi-Ming

    2016-05-21

    M8L12 cubic cages (M = Mn(II), Zn(II) or Cd(II)), with all eight metal ions having all facial Δ or facial Λ configurations and having an encapsulated anion, were prepared by the self-assembly of m-xylene-bridged imidazolyl-imine ligands and MX2 (X = PF6(-), SbF6(-), TfO(-)) salts; the encapsulated anion exchange with different anions (SbF6(-), Tf2N(-), NO3(-), TsO(-)) was studied and the results with NO3(-) and TsO(-) indicate that anions on the cage surfaces affect the encapsulated anion exchange and the occupancy of the cage. PMID:27064122

  14. Application of monohydric phenols as mobile-phase modifiers in the determination of anions by two-column ion chromatography

    International Nuclear Information System (INIS)

    The effect of monohydric phenols as eluant-modifying additives on the determination of I- and MoO42- anions by ion chromatography was studied. The following phenols were examined: pentafluorophenol, 4-nitrophenol, 2-nitrophenol, 2,4-dinitrophenol, and 4-chlorphenol. It was found that these phenols selectively affect the retention times of weakly and strongly retained anions. A correlation between pKa and the concentration of additive, and the retention times of anions was found. 12 refs., 3 figs., 3 tabs

  15. Influence of montmorillonites exchange capacity on the basal spacing of cation–anion organo-montmorillonites

    Energy Technology Data Exchange (ETDEWEB)

    Sanqin, Wu [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Zepeng, Zhang, E-mail: unite508@163.com [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Yunhua, Wang [Zhejiang Fenghong New Material Co., Ltd. (China); Libing, Liao [School of Materials Sciences and Technology, China University of Geosciences, No. 29 Xueyuan Road, Beijing, 100083 (China); Jiansheng, Zhang [Tangshan College, Tangshan 063000 (China)

    2014-11-15

    Graphical abstract: This picture shows the distribution of organic modifier (CTAB and SDS) in Mt interlayer and the basal spacing changes of Mt modified by CTAB and SDS. Organic modifier molecule in Mt interlayer is more and more orderly. The basal spacing of Mt is from 1.5 nm to 5 nm as modifier added. - Highlights: • The d{sub 001} of Ca-Mt, R-Na-Mt, Na-Mt modified by CTAB and SDS can reach 5 nm. • It is easier to get cation–anion OMt with greater d{sub 001} if CEC is lower. • The organic molecules distribution in cation–anion OMt was analyzed. • The influence mechanism of Ca-Mt CEC on the d{sub 001} was discussed. - Abstract: With cationic and anionic surfactants cetyltrimethylammonium bromide (CTAB) and sodium dodecylsulfonate (SDS) as modifiers, Ca-montmorillonites (Ca-Mt), artificial Na-montmorillonites (R-Na-Mt) and natural Na-montmorillonites (Na-Mt) with different cation exchange capacity (CEC) were modified by solution intercalation method, respectively. Then cation–anion organo-montmorillonites (OMt) were prepared. The influence of CEC on the basal spacing of cation–anion OMt and the influence mechanism were discussed by X-ray diffraction (XRD) and zeta potential testing. The results indicate that the basal spacing of cation–anion OMt is related to CEC. For the same type montmorillonites, the basal spacing of cation–anion OMt decreases with the increase of CEC and it is easier to get cation–anion OMt with greater basal spacing when CEC is lower. Moreover, the CEC of Na-Mt has the greatest influence on the basal spacing of cation–anion OMt.

  16. Performance evaluation method for an anion exchange resin and a method of controlling water processing system by using the method

    International Nuclear Information System (INIS)

    The present invention concerns a method of previously forecasting the limit for the use of an anion exchange resin to be used in a condensate desalting device in a nuclear power plant. A polystyrene sulfonic acid (PSS) is previously absorbed to an anion exchange resin and then a reaction rate of the anionic exchange resin is measured. The relation between the adsorbing amount of PSS and the reaction rate is measured, and the extent of degradation of the anionic exchange resin can be evaluated based on the PSS adsorption amount at a portion where the reaction rate is greatly lowered. Namely, the anionic exchange resin is more degraded as the reaction rate is lowered at a lesser adsorption amount, and it is judged that the resin is close to the working limit. With such procedures, the water processing system can be controlled stably. (T.M.)

  17. Determination of carbohydrates by high performance anion chromatography-pulsed amperometric detection in mushrooms.

    Science.gov (United States)

    Zhou, Shuai; Tang, Qingjiu; Luo, Xi; Xue, Jun-Jie; Liu, Yanfang; Yang, Yan; Zhang, Jingsong; Feng, Na

    2012-01-01

    A method of detecting carbohydrates (fucose, trehalose, mannitol, arabitol, mannose, glucose, galactose, fructose, and ribose) by high-performance anion chromatography-pulsed amperometric detection (HAPEC-PAD) was established. The conditions are: CarboPac MA1 column, NaOH as the eluent, temperature 30°C, Au working electrode, Ag/AgCl reference electrode, and flow rate 0.4 mL/min. These nine analytes, which yielded high resolution by this method, could be detected in 40 minutes. Mushrooms were tested and good precision, stability, and reproducibility were achieved. This method is suitable for mushroom samples and could support research and development on sugar and sugar alcohol, which contains special effects. PMID:23510179

  18. Determination of anionic surfactants during wastewater recycling process by ion pair chromatography with suppressed conductivity detection

    Science.gov (United States)

    Levine, L. H.; Judkins, J. E.; Garland, J. L.; Sager, J. C. (Principal Investigator)

    2000-01-01

    A direct approach utilizing ion pairing reversed-phase chromatography coupled with suppressed conductivity detection was developed to monitor biodegradation of anionic surfactants during wastewater recycling through hydroponic plant growth systems and fixed-film bioreactors. Samples of hydroponic nutrient solution and bioreactor effluent with high concentrations (up to 120 mS electrical conductance) of inorganic ions can be analyzed without pretreatment or interference. The presence of non-ionic surfactants did not significantly affect the analysis. Dynamic linear ranges for tested surfactants [Igepon TC-42, ammonium lauryl sulfate, sodium laureth sulfate and sodium alkyl (C10-C16) ether sulfate] were 2 to approximately 500, 1 to approximately 500, 2.5 to approximately 550 and 3.0 to approximately 630 microg/ml, respectively.

  19. THE TESTS AND MECHANISM ABOUT SODIUM IONS FROM AN ANION EXCHANGER

    Institute of Scientific and Technical Information of China (English)

    ZhuXingbao; YuJinchun; 等

    1996-01-01

    There exists a universal phenomena that sodium ions are leaked from the strong basic anion exdchanger in operation,which has been puzzling the researchers working in the field of water treatment for years.It is well known that the leakage of sodium ions will seriously affect the pruity of effluent.On the basis of lots of laboratory and industrial experiments,the mechanism of the sodium ions leaked from an anion exchanger has been preliminarily made out and some new chemical reaction equations as well as some improving measures have been put forward in this article.

  20. Hydrophilic interaction chromatography-mass spectrometry for anionic metabolic profiling of urine from antibiotic-treated rats

    NARCIS (Netherlands)

    Kok, Miranda G M; Swann, Jonathan R; Wilson, Ian D; Somsen, Govert W; de Jong, Gerhardus J

    2014-01-01

    Hydrophilic interaction chromatography-mass spectrometry (HILIC-MS) was used for anionic metabolic profiling of urine from antibiotic-treated rats to study microbial-host co-metabolism. Rats were treated with the antibiotics penicillin G and streptomycin sulfate for four or eight days and compared t

  1. Anion exchange behavior of Ti, Zr, Hf, Nb and Ta as homologues of Rf and Db in mixed HF-acetone solutions

    International Nuclear Information System (INIS)

    We studied in detail the sorption behavior of Ti, Zr, Hf, Nb and Ta on AG 1 anion exchange resin in HF-acetone mixed solutions as a function of organic cosolvent and acid concentrations. Anion exchange behavior was found to be strongly acetone concentration dependent. The distribution coefficients of Ti, Zr, Hf and Nb increased and those of Ta decreased with increasing content of acetone in HF solutions. With increasing HF concentration, anion exchange equilibrium analysis indicated the formation of fluoride complexes of group-4 elements with charge -3 and Ta with charge -2. For Nb the slope of -2 increased up to -5. Optimal conditions for separation of the elements using AIX chromatography were found. Group-4 elements formed MF73- (M = Ti, Zr, Hf) complexes whose sorption decreased Ti > Hf > Zr in reverse order of complex stability. This fact is of particular interest for studying ion exchange behavior of Rf compared to Ti. The advantages of studying chemical properties of Rf and Db in aqueous HF solutions mixed with organic solvents are briefly discussed

  2. Design of Anion Exchange Membranes and Electrodialysis Studies for Water Desalination

    Directory of Open Access Journals (Sweden)

    Muhammad Imran Khan

    2016-05-01

    Full Text Available Anion exchange membranes are highly versatile and nowadays have many applications, ranging from water treatment to sensing materials. The preparation of anion exchange membranes (AEMs from brominated poly(2,6-dimethyl-1,6-phenylene oxide (BPPO and methyl(diphenylphosphine (MDPP for electrodialysis was performed. The physiochemical properties and electrochemical performance of fabricated membranes can be measured by changing MDPP contents in the membrane matrix. The influence of a quaternary phosphonium group associated with the removal of NaCl from water is discussed. The prepared membranes have ion exchange capacities (IEC 1.09–1.52 mmol/g, water uptake (WR 17.14%–21.77%, linear expansion ratio (LER 7.96%–11.86%, tensile strength (TS 16.66–23.97 MPa and elongation at break (Eb 485.57%–647.98%. The prepared anion exchange membranes were employed for the electrodialytic removal of 0.1 M NaCl aqueous solution at a constant applied voltage. It is found that the reported membranes could be the promising candidate for NaCl removal via electrodialysis.

  3. Radioactive iodine waste treatment using electrodialysis with an anion exchange paper membrane

    International Nuclear Information System (INIS)

    In order to simply and safely treat radioactive iodine waste, a study of the removal of iodide ion from radioactive waste using electrodialysis with an anion exchange paper membrane, in which trimethylhydroxylpropylammonium groups were homogeneously dispersed with high density. In Na125I and Na36Cl concentration-cell system, electric ion and water conductances, phenomenological coefficients, have been experimentally determined on basis of nonequilibrium thermodynamics. Prepared paper membrane had higher permselectivity of 125I ion than 36Cl ions by approximately 21%. On the other hand, water flux that was accompanied by an ionic transference in prepared paper membrane was greatly larger than that in typical synthesized membrane. It is suggested that a depression of water mobility is important to practice an ideal radioactive iodide waste electrodialysis system with a novel anion exchange paper membrane

  4. Effects of Polar Organic Solvent on Separation of Y(edta)-/Nd(edta)- Complexes on Polyacrylic Anion Exchangers

    Institute of Scientific and Technical Information of China (English)

    Halina Hubicka; Dorota Kolodynska

    2005-01-01

    The use of polar organic solvents for the separations of rare earth elements (Ⅲ) is effective especially for their extensive separations despite the solubility limitations. The study shows that polyacrylate anion exchangers, particularly the weakly basic, gel anion exchanger Amberlite IRA 68, can be applied to the separation of rare earth complexes with EDTA in H2O-methanol and H2O-ethanol systems. In most cases the determined distribution coefficients of Ln3+ complexes with EDTA in mixed media like water-methanol on polyacrylate anion exchangers are larger than those in pure water media.

  5. Influence of glucose and urea on 125I transport across an anion exchange paper membrane

    International Nuclear Information System (INIS)

    In order to study the influence of glucose and urea on the 125I transport across an anion exchange paper membrane, the transmembrane potential, the fluxes, and the concentrations of 125I, glucose and urea within the membrane were measured in the Na125I concentration-cell system containing glucose or urea. Glucose and urea increased the membrane/solution distribution of the iodide ion, but scarcely affected the diffusion process of iodide ion within the membrane

  6. Comparison of anion exchange resins for recovering plutonium from nitric acid waste

    International Nuclear Information System (INIS)

    Microreticular and macroreticular anion exchange resins were compared for their capability of recovering plutonium from nitric acid waste streams. Plutonium breakthrough capacity and elution behavior of the resins were determined as a function of resin properties. Small-bead microreticular resins with a polystyrene matrix containing 4% divinylbenzene cross-linkage showed the best performance. Of the 20- to 50-mesh resins, the macroreticular resin, Amberlite IRA-938, gave the highest plutonium breakthrough capacity and eluted plutonium the fastest

  7. Development of imidazolium-type alkaline anion exchange membranes for fuel cell application

    OpenAIRE

    Ran, J; Wu, L.; XU, T; Varcoe, JR; Ong, AL; Poynton, SD

    2012-01-01

    This study reports the development of imidazolium-type alkaline anion exchange membranes (Im-AAEMs) based on the functionalization of bromomethylated poly(2,6-dimethyl-1,4-phenylene oxide) (BPPO) using 1-methylimdazole. Aromatic polymers bearing bromomethyl, instead of chloromethyl, functional groups were employed as base materials to avoid complicated chloromethylation which require toxic reagents. H NMR and FT-IR spectroscopic data indicated the synthesis of a series of membranes with contr...

  8. Studies on resin degradation products encountered during purification of plutonium by anion exchange

    International Nuclear Information System (INIS)

    Among the methods available for the purification of plutonium in Purex process, anion exchange method offers several advantages. However, on repeated use, the resin gets degraded due to thermal, radiolytic and chemical attacks resulting in chemical as well as physical damage. Frequently, plutonium product eluted from such resin contains significant quantities of white precipitates. A few anion exchange resins were leached with 8 M HNO3 at 60-80degC and the resin degradation products (RDP) in the leach-extract were found to give similar precipitates with tetravalent metal ions like Pu(IV), Th(IV) etc. Tetra propyl ammonium hydroxide in 8 M HNO3 (TPAN) also gave a white precipitate with plutonium similar to the one found in the elution streams. The results indicate that delinked quaternary ammonium functional groups might be responsible for the formation of precipitate. The characteristics of precipitates Th-RDP, Th-TPAN and that isolated from elution stream have been investigated. In a separate study a tentative formula for Th-RDP compound is proposed. The influence of RDP on the extraction of plutonium and other components in Purex process was studied and it was found that RDP complexes metal ions thus marginally affecting the kd values. A spectrophotometric method has been standardised to monitor the extent of degradation of anion exchange resins which is based on the ability of RDP to reduce the colour intensity of Th-thoron complex. This technique can be used to study the stability of the anion exchange resins. (author). 8 refs., 8 tabs., 5 figs.,

  9. Anion Exchange Capacity As a Mechanism for Deep Soil Carbon Storage in Variable Charge Soils

    Science.gov (United States)

    Dietzen, C.; James, J. N.; Ciol, M.; Harrison, R. B.

    2014-12-01

    Soil is the most important long-term sink for carbon (C) in terrestrial ecosystems, containing more C than plant biomass and the atmosphere combined. However, soil has historically been under-represented in C cycling literature, especially in regards to information about subsurface (>1.0 m) layers and processes. Previous research has indicated that Andisols with large quantities of noncrystalline, variable-charge minerals, including allophane, imogolite, and ferrihydrite, contain more C both in total and at depth than other soil types in the Pacific Northwest. The electrostatic charge of variable-charge soils depends on pH and is sometimes net positive, particularly in acid conditions, such as those commonly developed under the coniferous forests of the Pacific Northwest. However, even soils with a net negative charge may contain a mixture of negative and positive exchange sites and can hold some nutrient anions through the anion exchange capacity. To increase our understanding of the effects of variable-charge on soil organic matter stabilization, deep sampling is under way at the Fall River Long-Term Soil Productivity Site in western Washington. This site has a deep, well-drained soil with few rocks, which developed from weathered basalt and is classified as an Andisol of the Boistfort Series. Samples have been taken to a depth of 3 m at eight depth intervals. In addition to analyzing total soil C, these soils will be analyzed to determine functional groups present, cation exchange capacity, anion exchange capacity, and non-crystalline mineral content. These data will be analyzed to determine any correlations that may exist between these mineralogical characteristics, total soil C, and types of functional groups stored at depth. The most abundant organic functional groups, including carboxylic and phenolic groups, are anionic in nature, and soil positive charge may play an important role in binding and stabilizing soil organic matter and sequestering C.

  10. Study on the Retention Behavior of Aromatic Carboxylic and Sulfonic acid on a New Anion Exchange Column

    Institute of Scientific and Technical Information of China (English)

    SHI,Ya-Li; CAI,Ya-Qi; MOU,Shi-Fen

    2008-01-01

    Ion chromatography (IC) has gradually developed into a preferred method for the determination of inorganic anions. And in recent years some low molecular aliphatic acid can be also separated in the ion exchange column with the development of stationary phase. But for the determination of aromatic ionic compounds there are some problems. The aromatic anions show enhanced retention due to interaction with the π electrons of the aromatic backbone. Although the addition of an organic modifier can alleviate the difficulty, it is not the ultimate solution.IonPac AS20 column was developed using a unique polymer bonding technology and its substrate coating is aliphatic backbone. The polymer is completely free of any π electron-containing substituents in the AS20 column. In this paper, the retention behavior of aromatic carboxylic and sulfonic acid on two hydroxide-selective columns,IonPac AS11-HC, AS16, and the new column AS20 was also studied. The result showed that the retentions of ten compounds on three columns were different with each other because of their different column characteristics.Among them 4-chlorobenzene sulfonic acid, 3,5-dihydric benzoic acid and salicylic acid obviously exhibited the weakest retention on the IonPac AS20. It was showed that π-π bond function between anion and stationary phases was weakened in AS20 column because its polymer was completely free of any π electron-containing substituents.So in this paper the AS20 was selected as an analytical column to separate ten aromatic ionic compounds, fumaric acid with conjugate bond included. The retention behavior, separation of the ten compounds and effect of temperature on their retention in the anion-exchange column AS20 (2 mm) were studied. The result showed that those compounds could be separated with each other when running in gradient program and the organic modifier was unnecessary during the separation. So it is showed that AS20 column can be used as a separating column because its

  11. A basic study for the boron thermal regeneration system using anion exchange resins

    International Nuclear Information System (INIS)

    For the boron thermal regeneration system (BTRS), the basic characteristics of commercial anion exchange resin have been investigated on the swelling characteristics, absorption, desorption and temperature coefficient of exchange capacity for boric acid. The equilibrium capacity increases as decrease of temperature and depends strongly on the degrees of cross linking having a maximum point at about 7% of DVB. The temperature coefficient of equilibrium capacity of boric acid is also a function of the concentration of external solution and of the cross linking having a maximum point around 7% of DVB. (author)

  12. Retention behavior of C1-C6 aliphatic monoamines on anion-exchange and polymethacrylate resins with heptylamine as eluent.

    Science.gov (United States)

    Ohta, Kazutoku; Ohashi, Masayoshi; Jin, Ji-Ye; Takeuchi, Toyohide; Fujimoto, Chuzo; Choi, Seong-Ho; Ryoo, Jae Jeong; Lee, Kwang-Pill

    2004-06-11

    Retention behavior of C1-C6, aliphatic monoamines (methylamine, ethylamine, propylamine, butylamine, amylamine and hexylamine) on columns (150 mm x 6 mm i.d.) packed with various anion-exchange resins (styrene-divinylbenzene (PS-DVB) copolymer-based strongly basic anion-exchange resin: TSKgel SAX, polymethacrylate-based strongly basic anion-exchange resin: TSKgel SuperQ-5PW and polymethacrylate-based weakly basic anion-exchange resin: TSKgel DEAE-5PW) and unfunctionized polymethacrylate resins (TSKgel G5000PW and TSKgel G3000PWXL) was investigated with basic solutions (sodium hydroxide and heptylamine) as the eluents. Due to strongly electrostatic repulsion (ion-exclusion effect) between these anion-exchange resins and these amines, peak resolution between these amines on these anion-exchange resin columns was unsatisfactory with both sodium hydroxide and heptylamine as the eluents. In contrast, these polymethacrylate resins were successfully applied as the stationary phases for the separation of these C1-C6 amines with heptylamine as eluent, because of both small hydrophobicity and small cation-exchange ability of these resins. Excellent simultaneous separation, highly sensitive conductimetric detection and symmetrical peaks for these C1-C6 amines were achieved on the TSKgel G3000PWXL column in 35 min with 5 mM heptylamine at pH 11.1 as the eluent. PMID:15250421

  13. New Anion-Exchange Resins for Improved Separations of Nuclear Materials

    International Nuclear Information System (INIS)

    Improved separations of nuclear materials will have a significant impact upon a broad range of DOE activities. DOE-EM Focus Areas and Crosscutting Programs have identified improved methods for the extraction and recovery of radioactive metal ions from process, waste, and environmental waters as critical needs for the coming years. We propose to develop multifunctional anion-exchange resins that facilitate anion uptake by carefully controlling the structure of the anion receptor site. Our new ion-exchange resins interface the field of ion-specific chelating ligands with robust, commercial ion-exchange technology to provide materials which exhibit superior selectivity and kinetics of sorption and desorption. The following Focus Areas and Crosscutting Programs have described needs that would be favorably impacted by the new material: Efficient Separations and Processing - radionuclide removal from aqueous phases; Plutonium - Pu, Am or total alpha removal to meet regulatory requirement s before discharge to the environment; Plumes - U and Tc in groundwater, U, Pu, Am, and Tc in soils; Mixed Waste - radionuclide partitioning; High-Level Tank Waste - actinide and Tc removal from supernatants and/or sludges. The basic scientific issues which need to be addressed are actinide complex speciation along with modeling of metal complex/functional site interactions in order to determine optimal binding-site characteristics. Synthesis of multifunctionalized extractants and ion-exchange materials that implement key features of the optimized binding site, and testing of these materials, will provide feedback to the modeling and design activities. Resin materials which actively facilitate the uptake of actinide complexes from solution should display both improved selectivity and kinetic properties. The long-range implications of this research, however, go far beyond the nuclear complex. This new methodology of ''facilitated uptake'' could revolutionize ion-exchange technology

  14. DEVELOPMENT AND CHARACTERIZATION OF POLYVINYLIDENE FLUORIDE - IMIDAZOLIUM FUNCTIONALIZED POLYSULFONE BLEND ANION EXCHANGE MEMBRANE

    Directory of Open Access Journals (Sweden)

    S. VELU

    2015-09-01

    Full Text Available Anion exchange membrane (AEM is one of the core components of an alkaline fuel cell influencing the fuel cell’s performance, durability and stability. Out of the many anion exchange membranes reported so far, imidazolium functionalized polysulfone (PSf-ImOH membrane has been identified to have high hydroxide ionic conductivity, reaching up to 50 mS cm-1 at 20oC. However, at high levels of ion exchange capacity, the membrane’s water uptake and swelling ratio increases significantly with temperature thus destabilizing it and making it unfit for potential use in high temperature alkaline fuel cells. This limitation of PSf-ImOH membranes has been overcome by blending it with polyvinylidene fluoride (PVDF polymer, which is a thermally stable and highly hydrophobic polymer. PSf-ImOH membrane with a high degree of chloromethylation (180% was synthesized and blended with PVDF at different weight ratios (PVDF / PSf-ImOH: 30/70, 50/50 and 70/30 to create a series of novel anion exchange membranes. The prepared membranes were characterized to study their structure, water uptake, swelling ratio, solubility in low boiling water soluble solvents, thermal stability, ion exchange capacity (IEC and ionic conductivity (IC at different temperatures. The 70% PVDF blend membrane demonstrated the better performance in terms of IEC, IC and water uptake properties compared to other membranes. Comparative studies on the water uptake and IC variation between the 70% PVDF blend membrane and pure PSfImOH membrane (having the same IEC as that of the blend membrane, clearly indicated the superiority and the promising use of the blend membrane in alkaline fuel cell especially for high temperature working condition.

  15. Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy

    KAUST Repository

    Geise, Geoffrey M.

    2013-09-17

    Many salinity gradient energy technologies such as reverse electrodialysis (RED) rely on highly selective anion transport through polymeric anion exchange membranes. While there is considerable interest in using thermolytic solutions such as ammonium bicarbonate (AmB) in RED processes for closed-loop conversion of heat energy to electricity, little is known about membrane performance in this electrolyte. The resistances of two commercially available cation exchange membranes in AmB were lower than their resistances in NaCl. However, the resistances of commercially available anion exchange membranes (AEMs) were much larger in AmB than in NaCl, which would adversely affect energy recovery. The properties of a series of quaternary ammonium-functionalized poly(phenylene oxide) and Radel-based AEMs were therefore examined to understand the reasons for increased resistance in AmB to overcome this performance penalty due to the lower mobility of bicarbonate, 4.59 × 10-4 cm2/(V s), compared to chloride, 7.90 × 10-4 cm2/(V s) (the dilute aqueous solution mobility ratio of HCO3 - to Cl- is 0.58). Most membrane resistances were generally consistent with the dilute solution mobilities of the anions. For a few key samples, however, increased water uptake in AmB solution reduced the ionic resistance of the polymer compared to its resistance in NaCl solution. This increased water uptake was attributed to the greater hydration of the bicarbonate ion compared to the chloride ion. The increased resistance due to the use of bicarbonate as opposed to chloride ions in AEMs can therefore be mitigated by designing polymers that swell more in AmB compared to NaCl solutions, enabling more efficient energy recovery using AmB thermolytic solutions in RED. © 2013 American Chemical Society.

  16. The perchlorate anion is more effective than the trifluoroacetate anion as an ion-pairing reagent for reversed-phase chromatography of peptides

    OpenAIRE

    Shibue, M.; Mant, C.T.; Hodges, R.S.

    2005-01-01

    The addition of salts, specifically sodium perchlorate (NaClO4), to mobile phases at acidic pH as ion-pairing reagents for reversed-phase high-performance liquid chromatography (RP-HPLC) has been generally overlooked. To demonstrate the potential of NaClO4 as an effective anionic ion-pairing reagent, we applied RP-HPLC in the presence of 0–100 mM sodium chloride (NaCl), sodium trifluoroacetate (NaTFA) or NaClO4 to two mixtures of synthetic 18-residue peptides: a mixture of peptides with the s...

  17. Simultaneous quantification of sinigrin, sinalbin, and anionic glucosinolate hydrolysis products in Brassica juncea and Sinapis alba seed extracts using ion chromatography.

    Science.gov (United States)

    Popova, Inna E; Morra, Matthew J

    2014-11-01

    Although mustards such as Sinapis alba and Brassica juncea contain glucosinolates (sinalbin and sinigrin, respectively) that hydrolyze to form biopesticidal products, routine quality control methods to measure active ingredients in seed and seed meals are lacking. We present a simple and fast ion chromatography method for the simultaneous quantification of sinigrin, sinalbin, and anionic hydrolysis products in mustard seed to assess biological potency. Optimum conditions include isocratic elution with 100 mM NaOH at a flow rate of 0.9 mL/min on a 4 × 210 mm hydroxide-selective anion-exchange column. All anion analytes including sinigrin, sinalbin, SO4(2-), and SCN(-) yielded recoveries ranging from 83 to 102% and limits of detection ≤0.04 mM, with samples displaying little interference from plant matrix components. Sample preparation is minimized and analysis times are shortened to <90 min as compared with previous methods that took days and multiple instruments. PMID:25314611

  18. Models for the estimation of thermodynamic properties of layered double hydroxides: application to the study of their anion exchange characteristics

    OpenAIRE

    Bravo-Suárez Juan J.; Páez-Mozo Edgar A.; Oyama S. Ted

    2004-01-01

    Several models for the estimation of thermodynamic properties of layered double hydroxides (LDHs) are presented. The predicted thermodynamic quantities calculated by the proposed models agree with experimental thermodynamic data. A thermodynamic study of the anion exchange process on LDHs is also made using the described models. Tables for the prediction of monovalent anion exchange selectivities on LDHs are provided. Reasonable agreement is found between the predicted and the experimental mo...

  19. Hydration and sorption characteristics of a polyfunctional weak-base anion exchanger after the sorption of vanillin and ethylvanillin

    Science.gov (United States)

    Rodionova, D. O.; Voronyuk, I. V.; Eliseeva, T. V.

    2016-07-01

    Features of the sorption of substituted aromatic aldehydes by a weak-base anion exchanger under equilibrium conditions are investigated using vanillin and ethylvanillin as examples. Analysis of the sorption isotherms of carbonyl compounds at different temperatures allows us to calculate the equilibrium characteristics of their sorption and assess the entropy and enthalpy contributions to the energy of the process. Hydration characteristics of the macroporous weak-base anion exchanger before and after the sorption of aromatic aldehydes are compared.

  20. Modelling and optimization of the ion exchange membrane bioreactor for removal of anionic pollutants from drinking water streams

    OpenAIRE

    Ricardo, Ana Rita da Fonseca

    2011-01-01

    The present work aimed at studying the treatment of drinking water supplies contaminated with perchlorate and nitrate, using the Ion Exchange Membrane Bioreactor (IEMB) concept. This system combines the transport of these two anions from contaminated water, through an anion exchange membrane, with their biological reduction in a separate compartment. In the IEMB, the mass transport is dependent not only from membrane properties but also from the biocompartment conditions. Multivariate stat...

  1. Chemometrics optimization of carbohydrate separations in six food matrices by micellar electrokinetic chromatography with anionic surfactant.

    Science.gov (United States)

    Meinhart, Adriana D; Ballus, Cristiano A; Bruns, Roy E; Pallone, Juliana A Lima; Godoy, Helena T

    2011-07-15

    Multivariate statistical design modeling and the Derringer-Suich desirability function analysis were applied to micellar electrokinetic chromatography (MEKC) results with anionic surfactant to separate carbohydrates (CHOs) in different food matrices. This strategy has been studied with success to analyze compounds of difficult separation, but has not been explored for carbohydrates. Six procedures for the analysis of different sets of CHOs present in six food matrices were developed. The effects of pH, electrolyte and surfactant concentrations on the separation of the compounds were investigated using a central composite design requiring 17 experiments. The simultaneous optimization of the responses for separation of six sets of CHOs was performed employing empirical models for prediction of optimal resolution conditions in six matrices, condensed milk, orange juices, rice bran, red wine, roasted and ground coffee and breakfast cereal samples. The results indicate good separation for the samples, with appropriate detectability and selectivity, short analysis time, low reagent cost and little waste generation, demonstrating that the proposed technique is a viable alternative for carbohydrate analysis in foods. PMID:21645694

  2. Determination of sulfur anions by ion chromatography-postcolumn derivation and UV detection

    Institute of Scientific and Technical Information of China (English)

    Mei Lan Chen; Ming Li Ye; Xue Ling Zeng; Yun Chang Fan; Zhu Yan

    2009-01-01

    A novel method for determination of formaldehyde sulfoxylate, sulfite, thiocyanate, and thiosulfate in foodstuffs by ion chromatography separation with postcolumn derivation and UV detection has been developed. All species are separated at Dionex IonPac AG22A and AS22Awith mobile phase of a mixture of 4.5 mmol/L sodium carbonate and 0.8 mmol/L sodium bicarbonate at a flow-rate of 1.0 mL/min. The postcolumn derivation solution was 0.24% iodine in 0.2% phosphate acid and the detection wavelength was set at 288 nm. The detection limits (LOD, signal-to-noise ratio of 3) of formaldehyde sulfoxylate, sulfite, thiocyanate, and thiosulfate were 0.004, 0.006, 0.006, and 0.007 mg/L, respectively. Within-day relative standard deviations (RSD, n = 10) of formaldehyde sulfoxylate, sulfite, thiocyanate, and thiosulfate were 3.24%, 3.76%, 2.68%, and 2.07%, respectively. The recoveries of the four anions were in the range of 67.2-116.5%.

  3. Sorption of uranium(VI) ions from hydrochloric acid and ammonium chloride solutions by anion exchangers

    International Nuclear Information System (INIS)

    The sorption of macroscopic quantities of uranium from solutions of UO2Cl2 containing HCl and NH4Cl in concentrations from 0.0 to 6.0 M by the AV-17 x 8, AV-16G, EDE-10P, AN-31, AN-2F, AN22, and AN-251 anion exchangers has been investigated under static conditions. The sorption isotherms are described by an equation similar to Freundlich's equation: K/sub d/ = K tilde x C/sub eq/sup 1/z/ or log K/sub d/ = log K tilde + 1/z x log C/sub eq/. Equations describing the dependence of the sorbability (or K/sub d/) on the equilibrium concentration of uranium in the solution have been obtained with the aid of the least-squares method. Conclusions regarding the chemistry of the exchange of uranium ions on anion exchangers in chloride solutions have been drawn on the basis of the UV spectra of the original solutions and the IR spectra of the ion exchangers obtained in this work, as well as the established general laws governing sorption

  4. Sorption of uranium(VI) ions from hydrochloric acid and ammonium chloride solutions by anion exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Pakholkov, V.S.; Denisova, L.A.; Rychkov, V.N.; Kurnosenko, N.A.

    1988-01-01

    The sorption of macroscopic quantities of uranium from solutions of UO/sub 2/Cl/sub 2/ containing HCl and NH/sub 4/Cl in concentrations from 0.0 to 6.0 M by the AV-17 x 8, AV-16G, EDE-10P, AN-31, AN-2F, AN22, and AN-251 anion exchangers has been investigated under static conditions. The sorption isotherms are described by an equation similar to Freundlich's equation: K/sub d/ = K tilde x C/sub eq/sup 1/z/ or log K/sub d/ = log K tilde + 1/z x log C/sub eq/. Equations describing the dependence of the sorbability (or K/sub d/) on the equilibrium concentration of uranium in the solution have been obtained with the aid of the least-squares method. Conclusions regarding the chemistry of the exchange of uranium ions on anion exchangers in chloride solutions have been drawn on the basis of the UV spectra of the original solutions and the IR spectra of the ion exchangers obtained in this work, as well as the established general laws governing sorption.

  5. Synthesis and Characterization of Imidazolium Linear Bisphenol Polycarbonate Hydroxides for Anion Exchange Membrane.

    Science.gov (United States)

    Jang, Hohyoun; Hossain, Md Awlad; Lee, Soonho; Ha, Jaesung; Yoo, Jihoo; Kim, Kyungchul; Kim, Whangi

    2015-11-01

    A novel anion exchange membrane of imidazolium functionalized bisphenol polycarbonate was prepared for application in alkaline fuel cell. Di-imidazolium polycarbonate anionic membrane was synthesized by sequential interfacial polymerization, chloromethylation, substitution with 1-methylimidazole and ion exchange with 1.0 M KOH. Chloromethylation reaction was quantitative to achieve a high content of hydroxide ions. Introduction of conjugated imidazole ring in polymer plays an important role to improve both thermal and chemical stability. Bisphenol polycarbonate is a flexible polymer and shows a good solubility in polar organic solvent. The alkaline imidazolium bisphenol polycarbonate rendered an elevated molecular weight with excellent solubility in polar aprotic solvent. Different levels of substitution and ion exchange were investigated; the resulting membranes showed high ion exchange capacities (IECs) of up to 2.15 mmol g(-1). The imidazolium-functionalized copolymer membranes showed lower water affinity (14.2-42.8% at 30 degrees C) that satisfied an essential criterion for fuel cell application. The chemical structure of the imidazolium functionalized polycarbonate membrane was confirmed by 1H NMR spectroscopy, and also the membrane properties were evaluated by thermogravimetric analysis (TGA) and water uptake (WU), IEC and conductivity assessment. They exhibited hydroxide conductivity above 10(-2) S cm(-1) at room temperature and good chemical stability for up to five days without significant losses of ion conductivity. PMID:26726604

  6. Studies on the absorption of boric acid on anion exchange resin, (1)

    International Nuclear Information System (INIS)

    Boron Thermal Regeneration (BTR) with an anion exchange resin is a system for the control of boric acid concentration in the primary coolant of a pressurized water reactor. The absorption characteristics of boric acid on strong base anion exchange resin was investigated at 250C. Boric acid absorption was estimated by analysis of solution eluted with sodium chloride solution, from the ion exchange resin column. The average value adsorbed experimentally per ion exchange group was in the range of 1.4 to 4.2 for boric acid solutions in concentrations of 0.00925 to 0.647 mol dm-3. The pH within the borate form resin was pH 8 to 14 for boric acid solutions in concentrations of 0.00925 to 0.462 mol dm-3. The presence of orthoborate ion, tetraborate (mono and divalent) ion and pentaborate (mono and divalent) ion was anticipated in the resin phase. Acid dissociation constants (pK) of these five ion species were estimated to be 8.95 for orthoborate, 5.6 for monovalent tetraborate, 15.2 for divalent tetraborate, 5.6 for monovalent pentaborate and 13.8 for divalent pentaborate. (author)

  7. Preparation of highly concentrated super-hot (γ-32P)ATP using small-scale ion-exchange chromatography

    International Nuclear Information System (INIS)

    In order to obtain a highly concentrated, pure and super-hot [γ-32P]ATP, we improved the purification method of super-hot [γ-32P]ATP which was synthesized by the method of Johnson and Walseth (1979). The super-hot [γ-32P]ATP was synthesized in a relatively large volume (2 ml) of reaction mixture and purified using semi-micro scale anion exchange chromatography (Dowex 1 x 2, 60 - 70 μl column volume). In combination with washing the reaction product with certain organic solvents, this chromatography technique makes it possible to obtain a highly concentrated and pure super-hot [γ-32P]ATP (approx. 7000 Ci/mmol; 20 - 30 mCi/ml) from [32P]Pi of any commercial source in a good yield. (author)

  8. Removal of fluorescent dissolved organic matter in biologically treated textile effluents by NDMP anion exchange process: efficiency and mechanism.

    Science.gov (United States)

    Li, Wen-Tao; Xu, Zi-Xiao; Shuang, Chen-Dong; Zhou, Qing; Li, Hai-Bo; Li, Ai-Min

    2016-03-01

    The efficiency and mechanism of anion exchange resin Nanda Magnetic Polymer (NDMP) for removal of fluorescent dissolved organic matter in biologically treated textile effluents were studied. The bench-scale experiments showed that as well as activated carbon, anion exchange resin could efficiently remove both aniline-like and humic-like fluorescent components, which can be up to 40 % of dissolved organic matter. The humic-like fluorescent component HS-Em460-Ex3 was more hydrophilic than HS-Em430-Ex2 and contained fewer alkyl chains but more acid groups. As a result, HS-Em460-Ex3 was eliminated more preferentially by NDMP anion exchange. However, compared with adsorption resins, the polarity of fluorescent components had a relatively small effect on the performance of anion exchange resin. The long-term pilot-scale experiments showed that the NDMP anion exchange process could remove approximately 30 % of the chemical oxygen demand and about 90 % of color from the biologically treated textile effluents. Once the issue of waste brine from resin desorption is solved, the NDMP anion exchange process could be a promising alternative for the advanced treatment of textile effluents. PMID:26578375

  9. Molecular physiology and genetics of Na+-independent SLC4 anion exchangers

    Science.gov (United States)

    Alper, Seth L.

    2009-01-01

    Summary Plasmalemmal Cl–/HCO3– exchangers are encoded by the SLC4 and SLC26 gene superfamilies, and function to regulate intracellular pH, [Cl–] and cell volume. The Cl–/HCO3– exchangers of polarized epithelial cells also contribute to transepithelial secretion and reabsorption of acid–base equivalents and Cl–. This review focuses on Na+-independent electroneutral Cl–/HCO3– exchangers of the SLC4 family. Human SLC4A1/AE1 mutations cause the familial erythroid disorders of spherocytic anemia, stomatocytic anemia and ovalocytosis. A largely discrete set of AE1 mutations causes familial distal renal tubular acidosis. The Slc4a2/Ae2–/– mouse dies before weaning with achlorhydria and osteopetrosis. A hypomorphic Ae2–/– mouse survives to exhibit male infertility with defective spermatogenesis and a syndrome resembling primary biliary cirrhosis. A human SLC4A3/AE3 polymorphism is associated with seizure disorder, and the Ae3–/– mouse has increased seizure susceptibility. The transport mechanism of mammalian SLC4/AE polypeptides is that of electroneutral Cl–/anion exchange, but trout erythroid Ae1 also mediates Cl– conductance. Erythroid Ae1 may mediate the DIDS-sensitive Cl– conductance of mammalian erythrocytes, and, with a single missense mutation, can mediate electrogenic SO42–/Cl– exchange. AE1 trafficking in polarized cells is regulated by phosphorylation and by interaction with other proteins. AE2 exhibits isoform-specific patterns of acute inhibition by acidic intracellular pH and independently by acidic extracellular pH. In contrast, AE2 is activated by hypertonicity and, in a pH-independent manner, by ammonium and by hypertonicity. A growing body of structure–function and interaction data, together with emerging information about physiological function and structure, is advancing our understanding of SLC4 anion exchangers. PMID:19448077

  10. Selective removal of nitrate by using a novel macroporous acrylic anion exchange resin

    Institute of Scientific and Technical Information of China (English)

    Hai Ou Song; Yang Zhou; Ai Min Li; Sandra Mueller

    2012-01-01

    An anion exchange resin NDP-5 has been prepared successfully and applied on the selective removal of nit-ate from SO42-/NO3- binary co-existence system.The composition and morphology of NDP-5 were confirmed by FT-IR and SEM.The NDP-5 resin exhibits the completely different behavior on the adsorption capacity,adsorption kinetic and the effect of the completing anion in the absence or presence of sulfate,compared to D213.And,the resultants of kinetic are well fitted by the pseudo-first-order and pseudo-second-order models.These results are very important to develop novel resins with great features.

  11. Incorporation of multi-walled carbon nanotubes in microspheres used as anion exchange resin via suspension polymerization

    Science.gov (United States)

    Fathy, Mahmoud; Abdel Moghny, Th.; Awadallah, Ahmed E.; El-Bellihi, Abdel-Hameed A.-A.

    2014-06-01

    Amination of vinylbenzyl chloride-divinylbenzene (VBC-DVB) copolymers is an effective method for preparation of anion-exchange resins. Conventionally, the starting polymer is produced by chloromethylation of a styrene-divinylbenzene copolymer that utilizes chloromethyl methyl ether, a known carcinogen. An alterative approach is to copolymerize vinylbenzyl chloride with divinylbenzene to generate the necessary VBC-DVB. This method provides precise control over the density of the ion-exchange groups. The regiochemistry of the vinylbenzyl chloride methods was realized using solvent-ion exchange groups. These resulting anion-exchange polymers were characterized by a variety of techniques such as analytical titrations, transform infrared spectroscopy and thermal gravimetric analysis. Testing of these copolymers for breakthrough was performed. The results indicate that these anion exchangers have a meaningful increase in thermal stability over commercial anionic exchange beads. Resins containing MWCNTs achieved anion exchange capacity value of 323.6 meq/100 g over than that of copolymer resins and that useful in water desalination or treatment.

  12. Guanidinium based blend anion exchange membranes for direct methanol alkaline fuel cells (DMAFCs)

    Science.gov (United States)

    Sajjad, Syed D.; Liu, Dong; Wei, Zi; Sakri, Shambhavi; Shen, Yi; Hong, Yi; Liu, Fuqiang

    2015-12-01

    Guanidinium based blend anion exchange membranes (AEMs) for direct methanol alkaline fuel cells have been fabricated and studied. The guanidinium prepolymer is first synthesized through a simple polycondensation process with the ion exchange moieties incorporated directly into the polymer backbone, and then is used to make guanidinium - chitosan (Gu-Chi) blend membranes. Besides, a lipophilic guanidinium prepolymer, synthesized by means of a precipitation reaction between sodium stearate and guanidinium salt, is adopted to tune solubility and mechanical properties of the blend AEMs. Results show that both ionic conductivity and methanol permeability of the AEMs can be tuned by blend composition and chemistry of the guanidinium based prepolymer. The selectivity (ratio of ionic conductivity to methanol permeability) of the fabricated membranes is superior to that of commercial membranes. Under fuel cell tests using 3 M methanol, the open circuit voltage (OCV) value for the blend AEM with 72 wt% of the guanidinium polymer (0.69 V) is much higher than that of the commercial Tokuyama A201 (0.47 V) at room temperature, while the blend AEMs with 50 wt% guanidinium content still show comparable values. Overall, the developed membranes demonstrate superior performance and therefore pose great promise for direct methanol anion exchange fuel cell (DMAFC) applications.

  13. Studies on the adsorption of boric acid on anion exchange resins, 8

    International Nuclear Information System (INIS)

    Borate-form anion exchange resin (type I) is repeatedly used between the process of boric acid adsorption at a low temperature (5 0C) and its desorption at a high temperature (80 0C), to control the boric acid concentration of the primary coolant in PWRs. The thermal stability of the borate form anion exchange resin is an important index for evaluating operational reliability of the processes in the long term. To determine the thermal stability of the resins, heat cycle tests were carried out using borate, OH-, and Cl- form resins. Average mole values (average n) of boric acid adsorbed per functional group of the ion exchange resin were not changed by heat cycling. Residual ratios of salt spiliting capacity of the borate form resins decreased in the range of 92 to 97 % for 0.00924 to 0.185 M boric acid solution after 1700 heat cycles. The ratios for OH- or Cl- form resins which were tested as a reference, were 70 and 95 % respectively. The thermal stability of the resin decreased with an increase in the pH value in the resin phase. (author)

  14. The Drosophila Anion Exchanger (DAE lacks a detectable interaction with the spectrin cytoskeleton

    Directory of Open Access Journals (Sweden)

    Base Christine

    2010-06-01

    Full Text Available Abstract Background Current models suggest that the spectrin cytoskeleton stabilizes interacting ion transport proteins at the plasma membrane. The human erythrocyte anion exchanger (AE1 was the first membrane transport protein found to be associated with the spectrin cytoskeleton. Here we evaluated a conserved anion exchanger from Drosophila (DAE as a marker for studies of the downstream effects of spectrin cytoskeleton mutations. Results Sequence comparisons established that DAE belongs to the SLC4A1-3 subfamily of anion exchangers that includes human AE1. Striking sequence conservation was observed in the C-terminal membrane transport domain and parts of the N-terminal cytoplasmic domain, but not in the proposed ankyrin-binding site. Using an antibody raised against DAE and a recombinant transgene expressed in Drosophila S2 cells DAE was shown to be a 136 kd plasma membrane protein. A major site of expression was found in the stomach acid-secreting region of the larval midgut. DAE codistributed with an infolded subcompartment of the basal plasma membrane of interstitial cells. However, spectrin did not codistribute with DAE at this site or in anterior midgut cells that abundantly expressed both spectrin and DAE. Ubiquitous knockdown of DAE with dsRNA eliminated antibody staining and was lethal, indicating that DAE is an essential gene product in Drosophila. Conclusions Based on the lack of colocalization and the lack of sequence conservation at the ankyrin-binding site, it appears that the well-characterized interaction between AE1 and the spectrin cytoskeleton in erythrocytes is not conserved in Drosophila. The results establish a pattern in which most of the known interactions between the spectrin cytoskeleton and the plasma membrane in mammals do not appear to be conserved in Drosophila.

  15. Strong ion-exchange centrifugal partition chromatography as an efficient method for the large-scale purification of glucosinolates.

    Science.gov (United States)

    Toribio, Alix; Nuzillard, Jean-Marc; Renault, Jean-Hugues

    2007-11-01

    The glucosinolates sinalbin and glucoraphanin were purified by strong ion-exchange displacement centrifugal partition chromatography (SIXCPC). The optimized conditions involved the biphasic solvent system ethyl acetate/n-butanol/water (3:2:5, v/v), the lipophilic anion-exchanger Aliquat 336 (trioctylmethylammonium chloride, 160 and 408 mM) and a sodium iodide solution (80 and 272 mM) as displacer. Amounts as high as 2.4 g of sinalbin and 2.6g of glucoraphanin were obtained in one step in 2.5 and 3.5h respectively, starting from 12 and 25 g of mustard and broccoli seed aqueous extracts, using a laboratory scale CPC column (200 mL inner volume). PMID:17904564

  16. Synthesis and characterization of quaternized poly(phthalazinone ether sulfone ketone) for anion-exchange membrane

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chloromethylated poly(phthalazinone ether sulfone ketone) (CMPPESK) was prepared from poly(phthalazinone ether sulfone ketone) (PPESK) using chloromethyl octyl ethers (CMOE) with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and chloroform. Quatemized poly(phthalazinone ether sulfone ketone) (QAPPESK) was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance,which was only partly soluble in sulfuric acid (98%) and swollen in N,N-dimethylformamide (DMF). The vanadium redox flow battery (V-RFB) using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.

  17. Synergistic desorption of molybdenum from the strong base anion exchange resin by molybdnum fouling

    International Nuclear Information System (INIS)

    In this paper the synerglstic desorption of molybdenum from the strong base anion exchange resin is studied using ammonium hydroxide and ammonium sulfate, sodium hydroxide and sodium sulfate or sodium hydroxide and sodium chloride mixed chloride mixed desorbents. The coefficients of synergistlc desorption for various mixed desorbents are obtained. The experimental results show that the desorption efficiency of the mixed desorbent containing ammonium hydroxide and ammonium sulfate is so high that it can substitute for the mixed desorbent used in the plant. The harmful affect of the chloride ion on production can be eliminated if this mixed desorbent is used for the plant

  18. Ectopic expression of the erythrocyte band 3 anion exchange protein, using a new avian retrovirus vector

    DEFF Research Database (Denmark)

    Fuerstenberg, S; Beug, H; Introna, M;

    1990-01-01

    A retrovirus vector was constructed from the genome of avian erythroblastosis virus ES4. The v-erbA sequences of avian erythroblastosis virus were replaced by those coding for neomycin phosphotransferase, creating a gag-neo fusion protein which provides G418 resistance as a selectable marker. The...... exchange protein has been expressed from the vector in both chicken embryo fibroblasts and QT6 cells and appears to function as an active, plasma membrane-based anion transporter. The ectopic expression of band 3 protein provides a visual marker for vector function in these cells....

  19. Anion exchange equilibrium of uranium and several other elements in mineral acid solutions containing tetrafluoroboric acid

    International Nuclear Information System (INIS)

    Volume distribution coefficients (Dv) were determined for the adsorption of U and several other elements on anion-exchange resin from mixed solutions of tetrafluoroboric acid and nitric acid or hydrochloric acid, and the effect of tetrafluoroboric acid on the adsorption of each element was studied. The addition of tetrafluoroboric acid, in general, slightly decreased the Dv values while Zr weakly adsorbed in the HBF4-HCl and HBF4-HNO3 solutions and Nb in the NBF4-HNO3 solutions. (author) 18 refs.; 4 figs

  20. Determination of uranium isotopes in environmental samples by anion exchange in sulfuric and hydrochloric acid media.

    Science.gov (United States)

    Popov, L

    2016-09-01

    Method for determination of uranium isotopes in various environmental samples is presented. The major advantages of the method are the low cost of the analysis, high radiochemical yields and good decontamination factors from the matrix elements, natural and man-made radionuclides. The separation and purification of uranium is attained by adsorption with strong base anion exchange resin in sulfuric and hydrochloric acid media. Uranium is electrodeposited on a stainless steel disk and measured by alpha spectrometry. The analytical method has been applied for the determination of concentrations of uranium isotopes in mineral, spring and tap waters from Bulgaria. The analytical quality was checked by analyzing reference materials. PMID:27451111

  1. ELECTROCHEMICAL STABILITY OF STRONG BASIC ANION EXCHANGE MEMBRANES IN CONDITIONS OF HIGH INTENSIVE ELECTRODIALYSIS PROCESS

    Directory of Open Access Journals (Sweden)

    Zabolotskiy V. I.

    2014-12-01

    Full Text Available The stability of strongly basic anion-exchange membranes MA-41-2P (JSC "Schekino-Nitrogen", Russia and AMX (Tokuyama Soda, Japan under intensive current regimes was investigated in the current study. The process of water molecules dissociation at current densities above the limiting one in 0.01 M sodium chloride solution was studied in detail. The length of the electroconvective instability at the membrane / solution interface at currents exceeding the limiting current was measured by laser interferometry

  2. Extracellular Cl(-) regulates human SO4 (2-)/anion exchanger SLC26A1 by altering pH sensitivity of anion transport.

    Science.gov (United States)

    Wu, Meng; Heneghan, John F; Vandorpe, David H; Escobar, Laura I; Wu, Bai-Lin; Alper, Seth L

    2016-08-01

    Genetic deficiency of the SLC26A1 anion exchanger in mice is known to be associated with hyposulfatemia and hyperoxaluria with nephrolithiasis, but many aspects of human SLC26A1 function remain to be explored. We report here the functional characterization of human SLC26A1, a 4,4'-diisothiocyanato-2,2'-stilbenedisulfonic acid (DIDS)-sensitive, electroneutral sodium-independent anion exchanger transporting sulfate, oxalate, bicarbonate, thiosulfate, and (with divergent properties) chloride. Human SLC26A1-mediated anion exchange differs from that of its rodent orthologs in its stimulation by alkaline pHo and inhibition by acidic pHo but not pHi and in its failure to transport glyoxylate. SLC26A1-mediated transport of sulfate and oxalate is highly dependent on allosteric activation by extracellular chloride or non-substrate anions. Extracellular chloride stimulates apparent V max of human SLC26A1-mediated sulfate uptake by conferring a 2-log decrease in sensitivity to inhibition by extracellular protons, without changing transporter affinity for extracellular sulfate. In contrast to SLC26A1-mediated sulfate transport, SLC26A1-associated chloride transport is activated by acid pHo, shows reduced sensitivity to DIDS, and exhibits cation dependence of its DIDS-insensitive component. Human SLC26A1 resembles SLC26 paralogs in its inhibition by phorbol ester activation of protein kinase C (PKC), which differs in its undiminished polypeptide abundance at or near the oocyte surface. Mutation of SLC26A1 residues corresponding to candidate anion binding site-associated residues in avian SLC26A5/prestin altered anion transport in patterns resembling those of prestin. However, rare SLC26A1 polymorphic variants from a patient with renal Fanconi Syndrome and from a patient with nephrolithiasis/calcinosis exhibited no loss-of-function phenotypes consistent with disease pathogenesis. PMID:27125215

  3. Organic solvent and temperature-enhanced ion chromatography-high resolution mass spectrometry for the determination of low molecular weight organic and inorganic anions

    International Nuclear Information System (INIS)

    Highlights: • IC selectivity at high contents of organic solvent in eluent and elevated temperature is studied. • Solvent-enhanced IC coupled to high resolution MS is beneficial for sensitive detection of ions. • The first application of IC-HRMS to the detection of low explosives in fingermarks is shown. - Abstract: There has recently been increased interest in coupling ion chromatography (IC) to high resolution mass spectrometry (HRMS) to enable highly sensitive and selective analysis. Herein, the first comprehensive study focusing on the direct coupling of suppressed IC to HRMS without the need for post-suppressor organic solvent modification is presented. Chromatographic selectivity and added HRMS sensitivity offered by organic solvent-modified IC eluents on a modern hyper-crosslinked polymeric anion-exchange resin (IonPac AS18) are shown using isocratic eluents containing 5–50 mM hydroxide with 0–80% methanol or acetonitrile for a range of low molecular weight anions (<165 Da). Comprehensive experiments on IC thermodynamics over a temperature range between 20–45 °C with the eluent containing up to 60% of acetonitrile or methanol revealed markedly different retention behaviour and selectivity for the selected analytes on the same polymer based ion-exchange resin. Optimised sensitivity with HRMS was achieved with as low as 30–40% organic eluent content. Analytical performance characteristics are presented and compared with other IC-MS based works. This study also presents the first application of IC-HRMS to forensic detection of trace low-order anionic explosive residues in latent human fingermarks

  4. Organic solvent and temperature-enhanced ion chromatography-high resolution mass spectrometry for the determination of low molecular weight organic and inorganic anions

    Energy Technology Data Exchange (ETDEWEB)

    Gilchrist, Elizabeth S. [Analytical & Environmental Science Division, Department of Forensic & Analytical Science, King’s College London, 150 Stamford Street, London, SE1 9NH (United Kingdom); Nesterenko, Pavel N. [Australian Centre for Research on Separation Science, School of Physical Sciences, University of Tasmania, Private Bag 75, Hobart 7001 (Australia); Smith, Norman W. [Analytical & Environmental Science Division, Department of Forensic & Analytical Science, King’s College London, 150 Stamford Street, London, SE1 9NH (United Kingdom); Barron, Leon P., E-mail: leon.barron@kcl.ac.uk [Analytical & Environmental Science Division, Department of Forensic & Analytical Science, King’s College London, 150 Stamford Street, London, SE1 9NH (United Kingdom)

    2015-03-20

    Highlights: • IC selectivity at high contents of organic solvent in eluent and elevated temperature is studied. • Solvent-enhanced IC coupled to high resolution MS is beneficial for sensitive detection of ions. • The first application of IC-HRMS to the detection of low explosives in fingermarks is shown. - Abstract: There has recently been increased interest in coupling ion chromatography (IC) to high resolution mass spectrometry (HRMS) to enable highly sensitive and selective analysis. Herein, the first comprehensive study focusing on the direct coupling of suppressed IC to HRMS without the need for post-suppressor organic solvent modification is presented. Chromatographic selectivity and added HRMS sensitivity offered by organic solvent-modified IC eluents on a modern hyper-crosslinked polymeric anion-exchange resin (IonPac AS18) are shown using isocratic eluents containing 5–50 mM hydroxide with 0–80% methanol or acetonitrile for a range of low molecular weight anions (<165 Da). Comprehensive experiments on IC thermodynamics over a temperature range between 20–45 °C with the eluent containing up to 60% of acetonitrile or methanol revealed markedly different retention behaviour and selectivity for the selected analytes on the same polymer based ion-exchange resin. Optimised sensitivity with HRMS was achieved with as low as 30–40% organic eluent content. Analytical performance characteristics are presented and compared with other IC-MS based works. This study also presents the first application of IC-HRMS to forensic detection of trace low-order anionic explosive residues in latent human fingermarks.

  5. Ion-exchange chromatography by dicarboxyl cellulose gel.

    Science.gov (United States)

    Kim, U J; Kuga, S

    2001-06-01

    A new column packing material for ion-exchange chromatography was prepared from cellulose gel by periodate oxidation followed by chlorite oxidation to form spatially paired carboxyl groups (dicarboxyl cellulose, DCC). The carboxyl group was quantitatively introduced to spherical cellulose gel by controlling the extent of oxidation. The DCC gels were examined for their ion-exchange activity for various amines at pH of 2.5-5.5. In this pH range, aromatic amines with acid dissociation constant (pKa) below 2.7 showed no interaction with DCC gels as expected from their lack of protonation. The amines with pKa greater than 3.3, both aromatic and aliphatic, showed strong interaction corresponding to the amount of carboxyl introduced to the gel. However, these amines showed anomalous dependence on pH of the mobile phase, showing a maximum in retention factor at around pH 4. This is in contrast with the nearly constant retention factor of these amines on conventional carboxylated cellulose packing at pH greater than 4.0. The maximum retention factor at pH 4 of DCC gel was 4-5-times greater than that of conventional gel having a similar amount of carboxyls. Since pKa of dicarboxyl groups ranges 3-5 as determined by acid-base titration, the pH giving maximum retention corresponds to the pH at which one of paired carboxyls is dissociated. Possible cause of this anomaly is presented in terms of dissociation state of dicarboxyl groups and its interaction with amines. PMID:11459309

  6. Anion Effects on the Ion Exchange Process and the Deformation Property of Ionic Polymer Metal Composite Actuators

    Directory of Open Access Journals (Sweden)

    Wataru Aoyagi

    2016-06-01

    Full Text Available An ionic polymer-metal composite (IPMC actuator composed of a thin perfluorinated ionomer membrane with electrodes plated on both surfaces undergoes a large bending motion when a low electric field is applied across its thickness. Such actuators are soft, lightweight, and able to operate in solutions and thus show promise with regard to a wide range of applications, including MEMS sensors, artificial muscles, biomimetic systems, and medical devices. However, the variations induced by changing the type of anion on the device deformation properties are not well understood; therefore, the present study investigated the effects of different anions on the ion exchange process and the deformation behavior of IPMC actuators with palladium electrodes. Ion exchange was carried out in solutions incorporating various anions and the actuator tip displacement in deionized water was subsequently measured while applying a step voltage. In the step voltage response measurements, larger anions such as nitrate or sulfate led to a more pronounced tip displacement compared to that obtained with smaller anions such as hydroxide or chloride. In AC impedance measurements, larger anions generated greater ion conductivity and a larger double-layer capacitance at the cathode. Based on these mechanical and electrochemical measurements, it is concluded that the presence of larger anions in the ion exchange solution induces a greater degree of double-layer capacitance at the cathode and results in enhanced tip deformation of the IPMC actuators.

  7. Adsorption of Monobutyl Phthalate from Aqueous Phase onto Two Macroporous Anion-Exchange Resins

    Directory of Open Access Journals (Sweden)

    Zhengwen Xu

    2014-01-01

    Full Text Available As new emerging pollutants, phthalic acid monoesters (PAMs pose potential ecological and human health risks. In the present study, adsorption performance of monobutyl phthalate (MBP onto two macroporous base anion-exchange resins (D-201 and D-301 was discussed. It was found that the adsorption isotherms were best fitted by the Langmuir equation while the adsorption kinetics were well described by pseudo-first-order model. Analyses of sorption isotherms and thermodynamics proved that the adsorption mechanisms for DBP onto D-201 were ion exchange. However, the obtained enthalpy values indicate that the sorption process of MBP onto D-301 is physical adsorption. The equilibrium adsorption capacities and adsorption rates of DBP on two different resins increased with the increasing temperature of the solution. D-301 exhibited a higher adsorption capacity of MBP than D-201. These results proved that D-301, as an effective sorbent, can be used to remove phthalic acid monoesters from aqueous solution.

  8. Radiolysis of the AV-17×8 ČS anion-exchange resin

    Science.gov (United States)

    Bartoníček, B.; Habersbergerová, A.; Janovský, I.; Kysela, J.; Pejša, R.

    The mixture of the anion exchange resin AV-17×8 čs in borate form and of a deaerated aqueous solution containing H 3BO 3 and NH 3 ( pH = 7) was irradiated with gamma rays in both static and dynamic conditions. A loss of strong-base exchange capacity and an increase of weak-base capacity was observed. In the solution, (CH 3) 3N, (CH 3) 2NH and CH 3NH 2 were found as the radiolytic products, their relative ratio being 15.7 : 3.7 : 1. Further, NH 3 is formed with the concentration of the same order as that of CH 3NH 2. Beside hydrogen, which is the prevailing gaseous product of the radiolysis of the mixture, methane and ethane arise, their ratio in the dynamic irradiation being 2.8 to 6.0. The main features of the radiolysis are outlined.

  9. Radiolysis of the AV-17 x 8 cs anion-exchange resin

    International Nuclear Information System (INIS)

    The mixture of the anion exchange resin AV-17 x 8 cs in borate form and of a deaerated aqueous solution containing H3BO3 and NH3 (pH = 7) was irradiated with gamma rays in both static and dynamic conditions. A loss of strong-base exchange capacity and an increase of weak-base capacity was observed. In the solution, (CH3)3N, (CH3)2NH and CH3NH2 were found as the radiolytic products, their relative ratio being 15.7: 3.7: 1. Further, NH3 is formed with the concentration of the same order as that of CH3NH2. Beside hydrogen, which is the prevailing gaseous product of the radiolysis of the mixture, methane and ethane arise, their ratio in the dynamic irradiation being 2.8 to 6.0. The main features of the radiolysis are outlined. (author)

  10. ANION EXCHANGE CAPACITY OF CHROMATE ON MODIFIED ZEOLITE CLINOPTILOLITE WITH HDTMA-Br AND ITS REGENERATION

    Directory of Open Access Journals (Sweden)

    Widajanti Wibowo

    2011-04-01

    Full Text Available Zeolite Clinoptilolite from Lampung, located in South of Sumatra, had been modified with surfactanthexadecyltrimethylammonium bromide (HDTMA-Br as chromate anion exchanger. Surfactant modified zeolite (SMZClinoptilolite in particle size range of 1.5 - 2.0 mm, which contained 196.7 mmol HDTMA-Br/kg zeolite, was used foranion exchange of chromate at neutral pH. This experiment was conducted in a glass column filled with 5 gram SMZ.The breakthrough chromate exchange capacity was found 1.262 mg/g SMZ, while the total capacity was found 2.107mg/g SMZ. The regeneration of SMZ saturated with chromate was conducted using a mixed solutions of 0.28 MNa2CO3 and 0.5 M NaOH, compared with using a solution of 0.01 M Na2S2O4. The desorption of chromate achieved92% with the mixed solutions of Na2CO3 and NaOH and 90% with the Na2S2O4 solution. The regenerated SMZ withNa2CO3-NaOH solutions was prior washed with HCl solution to remove the carbonate from SMZ, before being used forchromate sorption again. Its breakthrough capacity was reduced to 1.074 mg/g SMZ, and to 0.724 mg/g SMZ whenregenerated with Na2S2O4 solution. These results indicated that regeneration of SMZ affected its exchange capacity foranion chromate. However, it is still could be acceptable, when Na2CO3/NaOH solutions were used for the regenerationof SMZ saturated with anion chromate.

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

    International Nuclear Information System (INIS)

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

  12. Evaluation of anion exchange resins for plutonium-uranium separations in nitric acid

    International Nuclear Information System (INIS)

    Pellicular, macroreticular and microreticular (gel type) anion exchange resins were compared for separation of plutonium from nitric acid solutions of mixed plutonium-uranium. All the macroreticular resins were 20 to 50 mesh beads. Dowex 1-X4 gel resin was 50 to 80 mesh beads. The resins were held in glass columns with coarse glass frits at the bottom of the columns. The top of the columns contained 50 ml reservoirs. The flow rates were controlled at 4 cm3.min-1.cm-2. One-centimeter bore columns with 15-cm resin bed heights were used for the plutonium elution and breakthrough capacity experiments, whereas 1.7 cm bore columns with 20 cm bed heights were used for the uranium washing experiments. As Pellionex SAX (pellicular resin) and Amberlite IRA-93 (weak base macroreticular anion exchange resin) were found to have better uranium washing and plutonium eluating characteristics than any of the resins tested. However, the capacity of the pellicular resin was much lower than that of the other resins. (T.G.)

  13. Removal of americium from effluent generated during the purification of plutonium by anion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Noronha, Donald M.; Pius, Illipparambil C.; Chaudhury, Satyajeet [Bhabha Atomic Research Centre, Mumbai (India). Fuel Chemistry Div.

    2015-07-01

    Studies have been carried out on removal of americium from the effluent generated during anion exchange purification of plutonium. Americium 241, generated by the beta decay of Plutonium-241, is the major source of a activity in this highly acidic effluent and its removal would render the waste easily disposable. A simple and effective co-precipitation method, using thorium oxalate has been investigated for the treatment of this alpha active aqueous waste. Experiments have been carried out to identify optimum conditions to obtain high percentage co-precipitation with minimum amount of co-precipitant. Efforts were carried out to correlate the optimum conditions of co-precipitation of americium obtained in these experiments with solubility of thorium oxalate and americium oxalate calculated from solubility products of these compounds, stability constants of thorium and americium oxalate complexes taken from literature. The saturation capacity of thorium oxalate for Am(III) was also calculated by analyzing the K{sub d} value data using Langmuir adsorption equation. The strong tendency of americium to get co-precipitated and the high capacity exhibited by thorium oxalate for the uptake of americium indicate feasibility of using this method for the treatment of anion exchange effluent.

  14. Qualification of Reillex{trademark} HPQ anion exchange resin for use in SRS processes

    Energy Technology Data Exchange (ETDEWEB)

    Crooks, W.J. III

    2000-05-18

    The Phase 2 portion of the HB-Line facility was built in the early 1980's to process plutonium and neptunium from nitric acid solutions into oxide suitable for storage in a vault. Although the other portions of HB-Line were started up in the mid 1980's and have operated since that time, the anion exchange and precipitation processes in Phase 2 were never started up. As part of the material stabilization efforts, Phase 2 is currently being started up. A new anion exchange resin is needed because the resins that were proposed for use 10 years ago are limited by performance characteristics, disposal requirements, or are no longer commercially available. SRTC is responsible for qualifying all resins prior to their use in Nuclear Materials Stabilization and Storage (NMSS) processes. Qualification consists of both process suitability and thermal stability with nitric acid. This report describes the thermal stability qualification of Reillex{trademark} HPQ, the new resin proposed for processing plutonium and neptunium in the HB Line facility.

  15. Use of Anion Exchange Resins for One-Step Processing of Algae from Harvest to Biofuel

    Directory of Open Access Journals (Sweden)

    Martin Poenie

    2012-07-01

    Full Text Available Some microalgae are particularly attractive as a renewable feedstock for biodiesel production due to their rapid growth, high content of triacylglycerols, and ability to be grown on non-arable land. Unfortunately, obtaining oil from algae is currently cost prohibitive in part due to the need to pump and process large volumes of dilute algal suspensions. In an effort to circumvent this problem, we have explored the use of anion exchange resins for simplifying the processing of algae to biofuel. Anion exchange resins can bind and accumulate the algal cells out of suspension to form a dewatered concentrate. Treatment of the resin-bound algae with sulfuric acid/methanol elutes the algae and regenerates the resin while converting algal lipids to biodiesel. Hydrophobic polymers can remove biodiesel from the sulfuric acid/methanol, allowing the transesterification reagent to be reused. We show that in situ transesterification of algal lipids can efficiently convert algal lipids to fatty acid methyl esters while allowing the resin and transesterification reagent to be recycled numerous times without loss of effectiveness.

  16. Separation of boron isotopes in anion exchange resin column. Isotopic enrichment of 10 B

    International Nuclear Information System (INIS)

    The separation of boron isotopes (10 B and 11 B) was carried out by isotopic exchange reaction between boric acid in solution and borate/poly borate anions adsorbed on an ammonium quaternary (Dowex 1 X 8 and 2 X 8) anion exchange resin packed in columns. Each resin column had 100 cm length and 1.4 cm in diameter. The columns were connected in series during displacement of boric bands. The enrichment line used pressure ranging from 2.5 to 3.0 Kg f.cm-2. N2 gas was used as in inert atmosphere in order to prevent C O2 formation. Enrichments in 10 B of 43% were obtained using Dowex 1 X 8 resin, 0.1 eq.L-1 H3 B O3 solution and band displacement of 1,876 cm. With Dowex 2 X 8 the enrichment was 40% with 1,330 cm of band displacement and 0.1 eq. L-1 H3 B O3. The boron isotopes were analysed, as methyl borate, by mass spectrometry. (author). 13 refs, 5 figs, 2 tabs

  17. Removal of americium from effluent generated during the purification of plutonium by anion exchange

    International Nuclear Information System (INIS)

    Studies have been carried out on removal of americium from the effluent generated during anion exchange purification of plutonium. Americium 241, generated by the beta decay of Plutonium-241, is the major source of a activity in this highly acidic effluent and its removal would render the waste easily disposable. A simple and effective co-precipitation method, using thorium oxalate has been investigated for the treatment of this alpha active aqueous waste. Experiments have been carried out to identify optimum conditions to obtain high percentage co-precipitation with minimum amount of co-precipitant. Efforts were carried out to correlate the optimum conditions of co-precipitation of americium obtained in these experiments with solubility of thorium oxalate and americium oxalate calculated from solubility products of these compounds, stability constants of thorium and americium oxalate complexes taken from literature. The saturation capacity of thorium oxalate for Am(III) was also calculated by analyzing the Kd value data using Langmuir adsorption equation. The strong tendency of americium to get co-precipitated and the high capacity exhibited by thorium oxalate for the uptake of americium indicate feasibility of using this method for the treatment of anion exchange effluent.

  18. The recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor

    International Nuclear Information System (INIS)

    This paper reports the optimization of the process parameters for recovery of zinc from hot galvanizing slag in an anion-exchange membrane electrolysis reactor. The experiments were carried out in an ammoniacal ammonium chloride system. The influence of composition of electrolytes, pH, stirring rate, current density and temperature, on cathodic current efficiency, specific power consumption and anodic dissolution of Zn were investigated. The results indicate that the cathode current efficiency increases and the hydrogen evolution decreased with increasing the cathode current density. The partial current for electrodeposition of Zn has liner relationship with ω1/2 (ω: rotation rate). The highest current efficiency for dissolving zinc was obtained when NH4Cl concentration was 53.46 g L-1 and the anodic dissolution of zinc was determined by mass transfer rate at stirring rate 0-300 r min-1. Increase in temperature benefits to improve CE and dissolution of Zn, and reduce cell voltage. Initial pH of electrolytes plays an important role in the deposition and anodic dissolution of Zn. The results of single factor experiment show that about 50% energy consumption was saved for electrodeposition of Zn in the anion-exchange membrane electrolysis reactor.

  19. A novel self-adaptive microalgae photobioreactor using anion exchange membranes for continuous supply of nutrients.

    Science.gov (United States)

    Fu, Qian; Chang, Hai-Xing; Huang, Yun; Liao, Qiang; Zhu, Xun; Xia, Ao; Sun, Ya-Hui

    2016-08-01

    A novel self-adaptive microalgae photobioreactor using anion exchange membranes (AEM-PBR) for continuous supply of nutrients was proposed to improve microalgae biomass production. The introduction of anion exchange membranes to the PBR can realize continuous supply of nutrients at desired rates, which is beneficial to the growth of microalgae. The results showed that the maximum biomass concentration obtained in the AEM-PBR under continuous supply of nitrogen at an average rate of 19.0mgN/L/d was 2.98g/L, which was 129.2% higher than that (1.30g/L) in a PBR with all the nitrogen supplied in batch at initial. In addition, the feeding rates of nitrogen and phosphorus were optimized in the AEM-PBR to maximize biomass production. The maximum biomass concentration of 4.38g/L was obtained under synergistic regulation of nitrogen and phosphorus feeding rates at 19.0mgN/L/d and 4.2mgP/L/d. The AEM-PBR demonstrates a promising approach for high-density cultivation of microalgae. PMID:27187567

  20. Anion exchange chromatographic distribution of human monoclonal immunoglobulin G is determined by heavy chain subclass and level of sialic acid expression

    Directory of Open Access Journals (Sweden)

    Ilić Vesna

    2012-01-01

    Full Text Available Anion exchange chromatography is widely accepted method for purification of immunoglobulins. In this work, we used human monoclonal immunoglobulin G (IgG with structure and solubility of normal human IgG as a model for studying chromatographic behavior of particular molecular forms of IgG. Human sera with monoclonal IgG were fractionated on strong anion exchanger, Q Sepharose Fast Flow. With 20 mM Tris pH 7.5 as a start buffer, 42% of human monoclonal IgG passed through column, and 58% of them remained adsorbed. Bound monoclonal IgG were eluted from the exchanger by linear increasing of concentration of NaCl from 0 to 0.5 M. Chromatographic distribution of human monoclonal IgG correlated with their electrophoretic mobility in agarose gels, and it was dependent on γ heavy chain isotype. Light chain type, as well as serum concentration of monoclonal IgG did not influence their chromatographic behavior. The level of heavy chain sialic acid expression, but not of galactose and N-acetylglucosamine, significantly determined chromatographic distribution of serum monoclonal IgG. Additionally to the information on the chromatographic behavior of human monoclonal IgG, we believe that presented data could provide useful information about the possible use of Q Sepharose Fast Flow matrix for the isolation of specific molecular forms of human IgG.

  1. Primary structure of a sperm cell anion exchanger and its messenger ribonucleic acid expression during spermatogenesis.

    Science.gov (United States)

    Holappa, K; Mustonen, M; Parvinen, M; Vihko, P; Rajaniemi, H; Kellokumpu, S

    1999-10-01

    Chloride/bicarbonate (Cl-/HCO(3)-) exchangers are a family of proteins (anion exchanger [AE] gene family) that regulate many vital cellular processes such as intracellular pH, cell volume, and Cl- concentration. They may also be involved in the regulation of sperm cell motility and acrosome reaction during fertilization, as these two phenomena are bicarbonate dependent, and we have previously shown that a polypeptide immunologically related to erythrocyte band 3 is expressed in mammalian sperm cells. We have now identified this putative sperm cell anion exchanger as the AE2 isoform of this gene family. First, we determined its complete primary structure from the human testis lambda gt 11 cDNA library. The cloned sequence was found to consist of 3896 base pairs (bp) with an open reading frame of 3726 bp, and to be almost identical to the previously published human genomic AE2 sequence. Only four amino acid disparities were found between these two sequences. Second, our in situ hybridization analyses showed that AE2 mRNA is expressed in developing sperm cells, indicating that the cloned sequence corresponds to the sperm cell AE. Our reverse transcription-polymerase chain reaction analyses suggested further that the expression of AE2 mRNA was variable to some extent during the epithelial cell cycle. Strongest expression was observed at stages VII-XIV except for stage X, i.e., when major structural and morphological changes take place. These results suggest that the full-length AE2 isoform regulates HCO(3)- transport in mature sperm cells and thus their motility in vivo. PMID:10491633

  2. Studies on the thermal and radiolytic resistance of an anion exchanger with benzimidazole functional groups in nitric acid solution

    International Nuclear Information System (INIS)

    Thermal and radiolytic resistance of AR-01R anion exchanger containing benzimidazole groups as exchange sites in nitric acid solution has been studied. Changes in its exchange capacity (EC), structure and shape were investigated and compared with those of a commercial Amberlite IRA-900 anion exchanger with quaternary ammonium group. Compared to the IRA-900, the AR-01R anion exchanger showed significantly higher thermal resistance and its decrease in EC was less than 10% after immersion in 9 mol·dm-3 solution for 72 h. On the other hand, it was found that the EC decrease of these two anion exchangers induced by γ-ray irradiation was almost the same; their EC decreased by 20-25% after irradiation in 9 mol·dm-3 HNO3 solution at room temperature with absorption dose of 3.0 MGy. The change of the strong-base benzimidazole group to weak-base benzimidazole group in AR-01 was found to be the main damage by heat and γ-ray irradiation. (author)

  3. Separation of phenolic acids from natural plant extracts using molecularly imprinted anion-exchange polymer confined ionic liquids.

    Science.gov (United States)

    Bi, Wentao; Tian, Minglei; Row, Kyung Ho

    2012-04-01

    Polymer-confined ionic liquids were used for the separation of phenolic acids from natural plant extract by utilizing an anion-exchange mechanism. They were synthesized using molecular imprinting technique to reduce non-directional ion-ion interactions during anion-exchange and other interactions with interference substances that could decrease selectivity. A suitable sorbent for phenolic acid separation could be identified based on the adsorption behaviors of phenolic acids on different polymer-confined ionic liquids. Thus, the developed ionic liquid-based molecularly imprinted anion-exchange polymer (IMAP) achieved high recovery rates by solid-phase extraction of phenolic acids from Salicornia herbacea L. extract: 90.1% for protocatechuic acid, 95.5% for ferulic acid and 96.6% for caffeic acid. Moreover, the phenolic acids were separable from each other by repeated solid phase extraction cycles. The proposed method could be used to separate other phenolic acids or organic acids from complex samples. PMID:21903215

  4. Separation of rare earths in nitric acid medium by a novel silica-based pyridinium anion exchange resin

    International Nuclear Information System (INIS)

    To separate rare earths in nitric acid medium by anion exchange process, a novel silica-based macro-reticular anion exchange resin (SiPyR-N4) with pyridinium as functional group has been synthesized. It was found that the SiPyR-N4 resin exhibits a quite strong adsorption for some rare earths especially the light rare earth elements such as La, Ce, Pr, Nd and Pm whose distribution coefficients onto SiPyR-N4 reach 10-25 dm3/kg-resin, which are much higher than the reported values for these elements with conventional anion exchange resins. The results from the column experiments show that the rare earths can be separated into the three groups: light, moderate and heavy rare earths and, a perfect separation between La-Pr group and Sm-Gd group can be achieved

  5. Impregnation process of insoluble cobalt ferrocyanide onto anion-exchange fiber prepared by radiation-induced graft polymerization

    International Nuclear Information System (INIS)

    The impregnation process of insoluble cobalt hexacyanidoferrate(II) onto an anion-exchange fiber was clarified. Vinylbenzyl trimethylammonium chloride and N-vinyl pyrrolidone were cograft-polymerized onto a 6-nylon fiber with an average diameter of 40 μm to obtain an anion-exchange capacity of 0.61 mmol/g. Hexacyanidoferrate(II) ions were adsorbed onto the anion-exchange fiber uniformly across the fiber. Subsequently, by immersing the fiber into cobalt chloride solution, hexacyanidoferrate(II) ions were quantitatively reacted with cobalt ions to form a precipitate at the periphery of the fiber. No leakage of this precipitate to the external solution was detected. The impregnation percentage, defined as the mass content of the precipitate in the resultant fiber, was 6.6%. (author)

  6. Separation of Fe (III) ions from acidic leach liquor of metasummatite Saghand ore by anion exchange resins

    International Nuclear Information System (INIS)

    Ferric ions in dilute acidic leach liquor of uranium ore of Saghand were separated by anion exchange resins. In this research, a simulated solution similar to the actual leach liquor of Saghand was prepared. The simulated solution which was containing chloride and ferric ions. rare earth elements, and some other impurities was treated by different types of Dowex anion exchange resins for ferric ions removal. It appeared that hydrochloric acidic concentration, resin types and particle sizes have a great impact on ferric ions adsorption. Dowex 1 X 4 (200-400 mesh) has the best adsorption of 91% in simulated solution and 79% in actual leach liquor of uranium ore of Saghand respectively

  7. Bifunctional Crosslinking Agents Enhance Anion Exchange Membrane Efficacy for Vanadium Redox Flow Batteries.

    Science.gov (United States)

    Wang, Wenpin; Xu, Min; Wang, Shubo; Xie, Xiaofeng; Lv, Yafei; Ramani, Vijay K

    2014-06-01

    A series of cross-linked fluorinated poly (aryl ether oxadiazole) membranes (FPAEOM) derivatized with imidazolium groups were prepared. Poly (N-vinylimidazole) (PVI) was used as the bifunctional cross-linking agent to: a) lower vanadium permeability, b) enhance dimensional stability, and c) concomitantly provide added ion exchange capacity in the resultant anion exchange membranes. At a molar ratio of PVI to FPAEOM of 1.5, the resultant membrane (FPAEOM-1.5 PVI) had an ion exchange capacity of 2.2 meq g-1, a vanadium permeability of 6.8×10-7 cm2 min-1, a water uptake of 68 wt.%, and an ionic conductivity of 22.0 mS cm-1, all at 25°C. Single cells prepared with the FPAEOM-1.5 PVI membrane exhibited a higher coulombic efficiency (> 92%) and energy efficiency (> 86%) after 40 test cycles in vanadium redox flow battery. The imidazolium cation showed high chemical stability in highly acidic and oxidizing vanadium solution as opposed to poor stability in alkaline solutions. Based on our DFT studies, this was attributed to the lower HOMO energy (-7.265 eV) of the HSO4- ion (compared to the OH- ion; -5.496 eV) and the larger HOMO-LUMO energy gap (6.394 eV) of dimethylimidazolium bisulfate ([DMIM] [HSO4]) as compared to [DMIM] [OH] (5.387 eV). PMID:24884171

  8. An efficient elution method of tetravalent uranium from anion exchanger by using formic acid solution

    International Nuclear Information System (INIS)

    In recent years, we have been investigating the development of the ERIX (The Electrolytic Reduction and Ion Exchange) process for reprocessing spent FBR-MOX fuel. This process uses electrolytic reduction and ion exchange techniques to recover U, Pu from spent FBR-MOX fuel solution. It was found that despite of the high nitric acid concentration, U(VI) can be effectively reduced to U(IV) using a flow type electrolytic cell in the existence of hydrazine and the U(IV) can be completely separated from fission products by the anion exchanger, AR-01. In addition, it was proposed that a part of U is assigned to be recovered together with Pu and Np for reusing as a FBR-MOX fuel. For that purpose, we are investigating an efficient elution method of Pu(IV) and U(IV) from AR-01. In this work, to develop an efficient elution method of U(IV) from AR-01, we have examined the U(IV) elution behavior by formic acid and the complex-formation of U(IV) with HCOO-

  9. Determination of common anions in oxalate by ion chromatography coupled with UV photolysis pretreatment

    Institute of Scientific and Technical Information of China (English)

    Sheng Lin Cao; Ming Li Ye; Wei De Lv; Guang Wen Pan; Ting Ting Zhang; Zhong Yang Hu; Li Na Liang; Yan Zhu

    2012-01-01

    A new and simple method was developed to determine anions in oxalate of analytical reagent grade.After UV photolysis with optimal 1% H2O2 in 10,000 mg/L oxalate in the fabricated photoreactor,sample was directly injected into IC system.Satisfactory linearity,detections limits,good repeatability and spiked recovery were obtained.The method was successfully applied to determine anions in two commercial oxalate samples.

  10. Fixation by anion exchange of toxic materials in a glass matrix

    International Nuclear Information System (INIS)

    This invention relates to the immobilization of toxic, e.g., radioactive materials, internally in a silicate glass or silica gel matrix for extremely long periods of time. Toxic materials, such as radioactive wastes containing radioactive anions, and in some cases cations, which may be in the form of liquids, or solids dissolved or dispersed in liquids or gases, are internally incorporated into a glass matrix, having hydrous organofunctionalsiloxy groups, E.G., hydrous aminoalkylsiloxy or carboxyorganosiloxy, bonded to silicon atoms of said glass and/or hydrous polyvalent metals bonded to silicon atoms of said glass through divalent oxygen linkages or otherwise immobilized therein, by a process which involves the ion exchange of said toxic, radioactive anions with hydroxyl groups attached to said organofunctionalsiloxy groups or with hydroxyl groups attached to the hydrous polyvalent metal. Thereafter, the resulting glass now characterized by a distribution of internally bonded or immobilized, toxic, radioactive anions can be packaged in suitable containers, and disposed of as by burial, and/or they can be sintered to collapse the pores thereof prior to disposal or for producing useful radiation sources. The porous glass or a porous silica gel having said silicon-bonded organofunctionalsiloxy groups and/or said hydrous polyvalent metal oxy groups, the pores of said glass or silica gel remaining open and uncollapsed, can be used advantageously as a backfill for an underground radioactive waste burial site and as overpack in the waste disposal container. Also included is a novel method for bonding the polyvalent metal to the porous silica glass or gel by substituting the protons of the silicon-bonded hydroxyl groups thereof with an alkali metal or ammonium cation followed by displacement of said cation with the non-radioactive polyvalent metal cation

  11. Efficient Separation of Lanthanides Using Poly (Styrene-Divinyl Benzene) Aminated Anion Exchanger

    International Nuclear Information System (INIS)

    New chromatographic method was developed for the determination and separation of lanthanides using AS4A anionic column. The behavior of the column towards lanthanides was studied through many parameters, From the data obtained it is found that, affinity of the column toward investigated ions increase by increasing eluent concentration and it decrease retention factors. With the two investigated eluent (oxalic and citric acids), elution order for lanthanide elements was obtained in their atomic number from La to Lu. Retention times and retention orders obtained at these conditions clearly show that, lanthanides in AS4A are displaced according to anion exchange mechanism. More over separation of lanthanides using AS4A was studied using isocratic and gradient elution programs. Light and the first intermediate lanthanide elements were separated successfully by applying a gradient program containing 70% oxalic acid (100 mM) and 30% water. The problem of separation for heavy and the last intermediate lanthanide elements was solved using 100 mM alpha hydroxy isobutyric acid (α-HIBA)

  12. An improved, computer-based, on-line gamma monitor for plutonium anion exchange process control

    International Nuclear Information System (INIS)

    An improved, low-cost, computer-based system has replaced a previously developed on-line gamma monitor. Both instruments continuously profile uranium, plutonium, and americium in the nitrate anion exchange process used to recover and purify plutonium at the Los Alamos Plutonium Facility. The latest system incorporates a personal computer that provides full-feature multichannel analyzer (MCA) capabilities by means of a single-slot, plug-in integrated circuit board. In addition to controlling all MCA functions, the computer program continuously corrects for gain shift and performs all other data processing functions. This Plutonium Recovery Operations Gamma Ray Energy Spectrometer System (PROGRESS) provides on-line process operational data essential for efficient operation. By identifying abnormal conditions in real time, it allows operators to take corrective actions promptly. The decision-making capability of the computer will be of increasing value as we implement automated process-control functions in the future. 4 refs., 6 figs

  13. Determination of metallic impurities in uranium through anion exchange separation and neutron activation analysis

    International Nuclear Information System (INIS)

    The separation of metals from uranium by anionic exchange was studied. The behaviour of ions in Dowex 1x8 in HNO3, H2SO4, HC1, HCL-HF, and NH3 media and Dowex 2x8 in H2SO4 medium were investigated. Methods for the separation of Na, Mg, Al, K, Ca, Sc, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Zr, Ag, Cd, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, La, Hf and Th were developed. For Mo, partial separation was obtained. Separation schemes for the neutron activation analysis of metallic impurities in uranium are proposed. The detection limits are given. The results for the elements Al, Cr, Mn, Co, Ni, Cu, V and Fe determined from the IAEA reference samples SR-54/64 are compared with recommended values

  14. REMOVAL OF GLUCORAPHENIN FROM THE EXTRACT OF RADISH PIGMENT BY ANION EXCHANGE RESIN 201×7

    Institute of Scientific and Technical Information of China (English)

    ZhouXiaohua; ChenQi

    1998-01-01

    A method for removimg glucoraphenin from the extract of Radish pigment by anion exchange resin 201×7 was studied.The adsorption capacity of 201×7 resin for glucoraphenin was 72.8mg/ml resin,the equilibrium time 55 minutes,and the optinum pH5.5.All glucoraphenin that had been adsorbed on 201×7 resin was eluted by 1.5BV.hr-1, eluent in whinc concentration of NaOH was 0.05mol·L-1 at the flow rate of 1.5BV/h.Extracting solution of deglucoraphenin was enriched by vacuum and spray drying.A powder product of Radish pigment was obtained and E1cm1%=4.30.

  15. Collaborative study of an anion exchange method for the determination of trace plutonium in water

    International Nuclear Information System (INIS)

    A single-laboratory evaluation and an interlaboratory collaborative study were made of a method for determining plutonium in water. The method was written for the analysis of one-liter samples and involves coprecipitation, acid dissolution, anion exchange, electrodeposition, and alpha pulse height analysis. After the single-laboratory evaluation of the selected method, four samples were prepared for the collaborative study: two river-water samples, a substitute ocean water sample, and sample containing sediment. These samples contained plutonium-239 and plutonium-238 at concentrations ranging from 0.42 to 28.9 dis/min/liter. In the collaborative study standard deviations of plutonium concentrations ranged from 5 to 13%. In three cases, standard deviations agreed with those expected from counting statistics. It is believed that hydrolysis occurred in the river water samples resulting in errors greater than those expected from counting statistics

  16. Synthesis and Properties of Anion Exchangers Derived from Chloromethyl Styrene Codivinylbenzene and Their Use in Water Treatment

    Directory of Open Access Journals (Sweden)

    Hesham A. Ezzeldin

    2010-01-01

    Full Text Available Amination of vinylbenzyl chloride-divinylbenzene (VBC-DVB copolymers is an effective method for preparation of ion-exchange resins. Conventionally, the starting polymer is produced by chloromethylation of a styrene-divinylbenzene copolymer that utilizes chloromethyl methyl ether, a known carcinogen. An alterative approach is to copolymerize vinylbenzyl chloride with divinylbenzene to generate the necessary VBC-DVB. This method provides precise control over the density of the ion-exchange groups. The regiochemistry of the vinylbenzyl chloride methods was realized using solvent-ion exchange groups. In this investigation, an improved solvent system was found for the preparation of anion exchange resins by the vinylbenzyl chloride route. The effectiveness of amination of the intermediate VBC-DVB polymers with a variety of trimethylamine reagents was investigated, and ethanolic trimethylamine produced the highest degree of amination. These resulting ion-exchange polymers were characterized by a variety of techniques such as analytical titrations, nitrogen analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. Testing of these copolymers for breakthrough was performed. The results indicate that these anion exchangers have a meaningful increase in thermal stability over commercial anionic exchange beads.

  17. Synthesis and Properties of Anion Exchangers Derived from Chloromethyl Styrene Co divinylbenzene and Their Use in Water Treatment

    International Nuclear Information System (INIS)

    Amination of vinylbenzyl chloride-divinylbenzene (VBC-DVB) copolymers is an effective method for preparation of ion-exchange resins. Conventionally, the starting polymer is produced by chloromethylation of a styrene-divinylbenzene copolymer that utilizes chloromethyl methyl ether, a known carcinogen. An alterative approach is to co polymerize vinylbenzyl chloride with divinylbenzene to generate the necessary Vb-Dvb. This method provides precise control over the density of the ion-exchange groups. The regiochemistry of the vinylbenzyl chloride methods was realized using solvent-ion exchange groups. In this investigation, an improved solvent system was found for the preparation of anion exchange resins by the vinylbenzyl chloride route. The effectiveness of amination of the intermediate VBC-DVB polymers with a variety of trimethylamine reagents was investigated, and ethanolic trimethylamine produced the highest degree of amination. These resulting ion-exchange polymers were characterized by a variety of techniques such as analytical titrations, nitrogen analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. Testing of these copolymers for breakthrough was performed. The results indicate that these anion exchangers have a meaningful increase in thermal stability over commercial anionic exchange beads

  18. Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell Membranes

    Science.gov (United States)

    Narayan, Sri R.; Yen, Shiao-Ping S.; Reddy, Prakash V.; Nair, Nanditha

    2012-01-01

    Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrene-based quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells. Imidazolium salts are known to be electrochemically stable over wide potential ranges. By controlling the relative ratio of imidazolium groups in polystyrene-imidazolium salts, their physiochemical properties could be modulated. Alkaline anion exchange membranes based on polystyrene-imidazolium hydroxide materials have been developed. The first step was to synthesize the poly(styrene-co-(1-((4-vinyl)methyl)-3- methylimidazolium) chloride through a free-radical polymerization. Casting of this material followed by in situ treatment of the membranes with sodium hydroxide solutions provided the corresponding hydroxide salts. Various ratios of the monomers 4-chloromoethylvinylbenzine (CMVB) and vinylbenzine (VB) provided various compositions of the polymer. The preferred material, due to the relative ease of casting the film, and its relatively low hygroscopic nature, was a 2:1 ratio of CMVB to VB. Testing confirmed that at room temperature, the new membranes outperformed commercially available membranes by a large margin. With fuel cells now in use at NASA and in transportation, and with defense potential, any improvement to fuel cell efficiency is a significant development.

  19. Efficient defluoridation of water using reusable nanocrystalline layered double hydroxides impregnated polystyrene anion exchanger.

    Science.gov (United States)

    Cai, Jianguo; Zhang, Yanyang; Pan, Bingcai; Zhang, Weiming; Lv, Lu; Zhang, Quanxing

    2016-10-01

    Water decontamination from fluoride is still a challenging task of global concern. Recently, Al-based layered double hydroxides (LDHs) have been extensively studied for specific fluoride adsorption from water. Unfortunately, they cannot be readily applied in scaled-up application due to their ultrafine particles as well as the regeneration issues caused by their poor stability at alkaline pHs. Here, we developed a novel (LDH)-based hybrid adsorbent, i.e., LALDH-201, by impregnating nanocrystalline Li/Al LDHs (LADLH) inside a commercial polystyrene anion exchanger D201. TEM image and XRD spectra of the resultant nanocomposite confirmed that the LDHs particles were nanosized inside the pores of D201 of highly crystalline nature and well-ordered layer structure. After impregnation, the chemical and mechanical stability of LALDH were significantly improved against pH variation, facilitating its application at a wide pH range (3.5-12). Fluoride adsorption onto LALDH-201 was compared to D201 and activated alumina, evidencing the preferable removal fluoride of LALDH-201. Fluoride adsorption onto LALDH-201 followed pseudo-second-order model, with the maximum capacity (62.5 mg/g from the Sips model) much higher than the other two adsorbents. Fixed-bed adsorption run indicated the qualified treatable volume of the fluoride contaminated groundwater (4.1 mg/L initially) with LALDH-201 was about 11 times as much as with the anion exchanger D201 when the breakthrough point was set as 1.5 mg/L. The capacity of LALDH-201 could be effectively refreshed for continuous column operation without observable loss by using the mixed solution of 0.01 M NaOH + 1 M NaCl. The above results suggested that the hybrid adsorbent LALDH-201 is very promising for water defluoridation in scaled-up application. PMID:27337346

  20. Application of a weak base anion exchange resin for recovery of uranium at Uravan, Colorado, U.S.A

    International Nuclear Information System (INIS)

    Resin ion-exchange technology has been used to recover uranium at the Uravan, Colorado plant for over 18 years; however, since the end of U.S. Atomic Energy Commission purchase of U3O8 concentrate in 1970, it has become necessary to develop techniques for upgrading the product to meet the more stringent specifications of private sales. The standard gel type quaternary ammonium anion exchange resin had been used previously. The development of the tertiary amine anion exchange resin, Amberlite XE-299, led to an experimental program of laboratory and pilot plant work to evaluate the resin on actual plant solutions. General information on ion-exchange resin structure and chemistry is discussed. Summary data of specific test work on loading the resin, various elution schemes, resin regeneration and product purity from the pilot plant tests and comments on actual plant operation using Amberlite XE-299 resin are presented. (author)

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

    Science.gov (United States)

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

    2004-06-11

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

  2. Electron exchange between dipole-bound anion and polar molecule and dipole-bound anions dimer formation

    International Nuclear Information System (INIS)

    We consider collision between a dipole-bound molecular anion and a neutral polar molecule and show that the excess electron can bind two neutral molecules into a dimer. Using a variational approach similar to the Heitler-London model of H''+2 ion we obtain the energy terms of such a dimer. Their difference determines the cross-section of electron transfer from the anion to the neutral molecule in quasiclassical near-resonant Born-Oppenheimer approximation. We obtain for the cross-section an analytic expression containing the weak (logarythmic) factor depending on the molecular dipole moment, and collision velocity. Our analytic calculations are in a good accordance with the results of a recent experiment.

  3. Determination of plutonium, uranium and americium/curium isotopes in environmental samples with anion exchange, UTEVA, Sr and DGA resin

    International Nuclear Information System (INIS)

    This study presents a quantitative sequential radiochemical separation method for the Pu, U, Sr and Am/Cm isotopes with an anion exchange resin, UTEVA resin, Sr resin and DGA resin in environmental samples. After the radionuclides were leached from samples with 8M HNO3, the Pu, U, Sr and Am/Cm isotopes were sequentially adsorbed on the anion exchange column, UTEVA column connected with Sr Spec column and DGA column. The Pu isotopes were purified from other nuclides through the anion exchange column, and the uranium isotopes were separated from other nuclides through the UTEVA column. Also, 90Sr was separated from other hindrance elements such as Ca2+, Ba2+ and Y3+ with the Sr Spec column. Finally, Am/Cm fractions were purified with the DGA and anion exchange resins. After α source preparation for the purified Pu, U and Am/Cm isotopes with the micro-coprecipitation method, the Pu, U and Am/Cm isotopes were measured by an alpha spectrometry. Strontium-90 was measured by a low level liquid scintillation counter. The radiochemical procedure for Pu, U and Am nuclides investigated in this study has been validated by application to IAEA Reference soils. (orig.)

  4. Adsorption of uranium (VI) from mixed chloride-fluoride solutions by anion-exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Pakholkov, V.S.; Denisova, L.A.; Rychkov, V.N.; Kurnosenko, N.A.

    1988-03-01

    Experimental data are reported and discussed concerning the adsorption of uranium from 0.025 M solutions of UO/sub 2/Cl/sub 2/, containing HCl, HF, and NH/sub 4/Cl over a wide concentration range, using anion-exchange resins of varying basicities. UV and IR spectroscopic studies were conducted in order to clarify the chemical mechanism of uranium adsorption. Adsorption isotherms for all of the ion-exchange resins studied are convex in shape and can be described by the following equations: log K/sub d/ = a + b (-log C/sub e/), and log A = a + (b + 1) log C/sub e/, where A is the adsorptivity in mmole U/g; K/sub d/ is the distribution coefficient in mg/liter; and C/sub e/ is the equilibrium concentration of U in mmole/ml. General mathematical models have been obtained to describe the adsorption process; these consist of a system of regression equations derived from the results of a complete 2/sup 3/ factorial study.

  5. Adsorption characteristics of boric acid on strong-base anion exchange resin

    International Nuclear Information System (INIS)

    The Boron Thermal Regeneration System (BTRS) is capable of controlling boron concentration in primary coolant and reducing the amount of liquid waste at the end of fuel cycle in a pressurized water reactor, but the system has not been in effective operation yet because of the lack of detailed information regarding the boron adsorption characteristics of the ion exchange resin packed in the demineralizers of BTRS. In this study, the adsorption characteristics of boric acid on a strong-base anion exchange resin, an Amberlite IRN-78LC resin in OH- form, were investigated at temperature from 10 .deg. C to 60 .deg. C in the concentrations of boron up to 1500 ppm covering the BTRS operational conditions. A computer code was developed to calculate the composition of borate ions in solution as a function of boron concentration, temperature and pH. From the calculated composition of borate ions and experimental data of adsorption equilibrium, the model was proposed for the adsorption isotherm of boric acid on the resin. The diffusion coefficient of the boric acid in the resin was calculated by the particle diffusion model and found that the temperature dependency of the coefficient follows an Arrhenius equation. The results in this study can be applied for the optimum operation of BTRS

  6. Effect of temperature (and the degree of crosslinking) on the reactivity of anion-exchange resins by applying the OT-for-OH exchange reaction

    International Nuclear Information System (INIS)

    In order to reveal (i) the exchange ability of OT- resulting from the dissociation of HTO, (ii) the effect of temperature on the reactivity of anion-exchange resins, and (iii) the effect of the degree of crosslinking on the reactivity of the resins, the OT-for-OH exchange reaction between each OH--form anion-exchange resin and HTO water was observed in the equilibrium state. The anion-exchange resins used were Amberlite IRA-400, and Biorad AG1-X2, X4, X8. The temperature used was 20, 30, 40, 60 or 80 C. The activity of each resin based on the OT-forcounter. Analyzing the data obtained, it ws found that: (1) the higher the temperature is, the smaller is the activity of IRA-400 resin within the range of 40-80 C; (2) the larger the degree of crosslinking in each Biorad AG1 resin, the lower the activity of the resin. Accordingly, it can be concluded that: (1) as for the dissociation of HTO at high temperature, the formula (HTOT++OH-) is more predominant than the formula (HTOH++OT-); (2) the resin with lower porosity (i.e., the resin having the larger degree of crosslinking) shows a lesser tendency for the OT-for-OH exchange reaction to occur than the resin with a higher porosity. (orig.)

  7. L(+-Lactic acid recovery from cassava bagasse based fermented medium using anion exchange resins

    Directory of Open Access Journals (Sweden)

    Rojan P. John

    2008-12-01

    Full Text Available The properties of the ion exchange resins, Amberlite IRA 402, a strong anion exchange resin and IRA 67, a weak anion exchange resin were determined to evaluate their comparative suitability for lactic acid recovery from fermented cassava bagasse. Data on binding capacities and recovery proved that weak base resin in chloride form was the most favourable ones for lactic acid recovery from aqueous solutions and fermentation media. Fermented media obtained through simultaneous saccharification and fermentation of cassava bagasse starch hydrolysate based medium were used for lactic acid recovery study using weak base resin column. Amberlite IRA 67 had much more efficiency than Amberlite IRA 402 to recover lactic acid. Like in other reports, due to the presence of nutrients and ions other than lactate, the binding capacity was slightly lesser while using fermented media (~93% instead of aqueous lactic acid solutions (~98%.As propriedades das resinas de troca iônica, da Amberlite IRA 402, uma resina de troca aniônica forte, e da IRA 67, uma resina de troca aniônica fraca, foram determinadas para se avaliar a adequabilidade comparativa delas à obtenção de ácido lático de bagaço de mandioca fermentado. Dados sobre a capacidade de ligação e sobre a obtenção provaram que a resina de base fraca na forma de cloreto era a mais adequada para a obtenção de ácido lático em soluções aquosas e meios de fermentação. Os meios de fermentação obtidos da sacarificação e da fermentação simultâneas de meios baseados hidrolisados de fécula de bagaço de mandioca foram usados para o estudo da obtenção de ácido lático usando uma coluna de resina de base fraca. A Amberlite IRA 67 mostrou-se muito mais eficaz do que a Amberlite IRA 402 para a obtenção de ácido lático. Como em outros relatórios, devido à presença de nutrientes e íons que não lactatos, a capacidade de ligação foi ligeiramente inferior enquanto se utilizavam meios

  8. High-Capacity and Rapid Removal of Refractory NOM Using Nanoscale Anion Exchange Resin.

    Science.gov (United States)

    Johnson, Billy R; Eldred, Tim B; Nguyen, Andy T; Payne, William M; Schmidt, Emily E; Alansari, Amir Y; Amburgey, James E; Poler, Jordan C

    2016-07-20

    As human health concerns over disinfection byproducts (DBP) in drinking water increase, so does the need to develop new materials that remove them rapidly and at high capacity. Ion exchange (IEX) is an effective method for the removal of natural organic matter (NOM), especially anion exchange resins (AERs) with quaternary ammonium functional groups. However, capacity is limited in existing commercial resin materials because adsorbates can only interact with the outermost surface area, which makes these products inefficient on a mass basis. We have synthesized a novel "NanoResin" exploiting the enhanced NOM removal of the quaternary ammonium resin while utilizing the vast surface area of SWCNTs, which act as scaffolding for the resin. Our nanomaterials show increased adsorption capacity compared to commercially available adsorbents, in a fraction of the time. This NanoResin requires only about 10 s to reach ion-exchange equilibrium. Comparatively, commercial AERs only achieved partial removal after more than 30 min. High capacity adsorption of a low molecular weight (MW) surrogate has been measured. NOM removal was demonstrated in solutions of both low and high specific UV absorbance (SUVA) composition with these nanomaterials. Additionally, the NanoResin showed enhanced removal of a NOM concentrate sample taken from Myrtle Beach, SC, demonstrating NanoResin is an effective method of removal for refractory NOM in a natural aqueous environment. Synthesis and characterization of the polymers and nanomaterials are presented below. Adsorption capacity, adsorption kinetics, and the regeneration and reusability of these new materials for NOM removal are described. The open matrix microstructure precludes any intraparticle diffusion of adsorbates; thus, these nanomaterials act as a "contact resin". PMID:27348616

  9. Methods development for separation of inorganic anions, organic acids and bases, and neutral organic compounds by ion chromatography and capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.

    1999-04-01

    A novel anion-exchange resin containing three amine groups was prepared by reaction of a chloromethylated polystyrene-divinylbenzene (PS-DVB) resin with diethylenetriamine. After being protonated by contact with an aqueous acid, this resin can be used for ion chromatographic separation of anions. The charge on the resins can be varied from +1 to +3 by changing the mobile phase pH. The selectivity of the new ion exchangers for various inorganic anions was quite different from that of conventional anion exchangers. The performance of this new anion exchanger was studied by changing the pH and the concentration of the eluent, and several different eluents were used with some common anions as testing analytes. Conductivity detection and UV-visible detection were applied to detect the anions after separation. The new resin can also be used for HPLC separation of neutral organic compounds. Alkylphenols and alkylbenzenes were separated with this new polymeric resin, and excellent separations were obtained under simple conditions. This report contains Chapter 1: General introduction and Chapter 6: General conclusions.

  10. Dowex anion exchanger-loaded-baker's yeast as bi-functionalized biosorbents for selective extraction of anionic and cationic mercury(II) species

    International Nuclear Information System (INIS)

    Dowex anion exchanger-immobilized-baker's yeast [Dae-yeast] were synthesized and potentially applied as environmental friendly biosorbents to evaluate the up-take process of anionic and cationic mercury(II) species as well as other metal ions. Optimization of mass ratio of Dowex anion exchanger versus yeast (1:1-1:10) in presence of various interacting buffer solutions (pH 4.0-9.0) was performed and evaluated. Surface modification of [Dae-yeast] was characterized by scanning electron microscopy (SEM) and infrared spectroscopy. The maximum metal biosorption capacity values of [Dae-yeast] towards mercury(II) were found in the range of 0.800-0.960, 0.840-0.950 and 0.730-0.900 mmol g-1 in presence of buffer solutions pH 2.0, 4.0 and 7.0, respectively. Three possible and different mechanisms are proposed to account for the biosorption of mercury and mercuric species under these three buffering conditions based on ion exchange, ion pair and chelation interaction processes. Factors affecting biosorption of mercury from aqueous medium including the pH effect of aqueous solutions (1.0-7.0), shaking time (1-30 min) and interfering ions were searched. The potential applications of modified biosorbents for selective biosorption and extraction of mercury from different real matrices including dental filling waste materials, industrial waste water samples and mercury lamp waste materials were also explored. The results denote to excellent percentage extraction values, from nitric acid as the dissolution solvent with a pH 2.0, as determined in the range of 90.77-97.91 ± 3.00-5.00%, 90.00-93.40 ± 4.00-5.00% and 92.31-100.00 ± 3.00-4.00% for the three tested samples, respectively.

  11. Model of a vanadium redox flow battery with an anion exchange membrane and a Larminie-correction

    Science.gov (United States)

    Wandschneider, F. T.; Finke, D.; Grosjean, S.; Fischer, P.; Pinkwart, K.; Tübke, J.; Nirschl, H.

    2014-12-01

    Membranes are an important part of vanadium redox flow battery cells. Most cell designs use Nafion®-type membranes which are cation exchange membranes. Anion exchange membranes are reported to improve cell performance. A model for a vanadium redox flow battery with an anion exchange membrane is developed. The model is then used to calculate terminal voltages for open circuit and charge-discharge conditions. The results are compared to measured data from a laboratory test cell with 40 cm2 active membrane area. For higher charge and discharge currents, an empirical correction for the terminal voltage is proposed. The model geometry comprises the porous electrodes and the connected pipes, allowing a study of the flow in the entrance region for different state-of-charges.

  12. The isotope separation by ion exchange chromatography. Application to the lithium isotopes separation

    International Nuclear Information System (INIS)

    In this work is described the used study step to demonstrate the industrial feasibility of a lithium isotopes separation process by ion exchange chromatography. After having recalled how is carried out the exchange reaction between the lithium isotopes bound on the cations exchanger resin and those which are in solution and gave the ion exchange chromatography principle, the authors establish a model which takes into account the cascade theory already used for enriched uranium production. The size parameters of this model are: the isotopic separation factor (which depends for lithium of the ligands nature and of the coordination factor), the isotopic exchange kinetics and the mass flow (which depends of the temperature, the lithium concentration, the resins diameter and the front advance). The way they have to be optimized and the implementation of the industrial process are given. (O.M.)

  13. Sodium citrate-assisted anion exchange strategy for construction of Bi2O2CO3/BiOI photocatalysts

    International Nuclear Information System (INIS)

    Highlights: • Heterostructured Bi2O2CO3/BiOI microspheres were prepared via anion exchange. • Sodium citrate-assisted anion exchange for construction of composite photocatalysts. • Bi2O2CO3/BiOI composites show high visible light photocatalytic activity. - Abstract: Bi2O2CO3/BiOI heterojuncted photocatalysts were constructed through a facile partial anion exchange strategy starting from BiOI microspheres and urea with the assistance of sodium citrate. The content of Bi2O2CO3 in the catalysts was regulated by modulating the amount of urea as a precursor, which was decomposed to generate CO32− in the hydrothermal process. Citrate anion plays a key role in controlling the morphology and composition of the products. The Bi2O2CO3/BiOI catalysts display much higher photocatalytic activity than pure BiOI and Bi2O2CO3 towards the degradation of rhodamine B (RhB) and bisphenol A (BPA). The enhancement of photocatalytic activity of the heterojuncted catalysts is attributed to the formation of p–n junction between p-BiOI and n-Bi2O2CO3, which is favorable for retarding the recombination of photoinduced electron-hole pairs. Moreover, the holes are demonstrated to be the main active species for the degradation of RhB and BPA

  14. Development and characterization of direct ethanol fuel cells using alkaline anion-exchange membranes

    Science.gov (United States)

    Lim, Peck Cheng

    2009-08-01

    Alkaline membrane fuel cell (AMFC) is a relatively new fuel cell technology that is generating considerable interests. It offers the electrocatalytic advantages of conventional alkaline fuel cells, and the manufacturing and cost advantages of solid polymer electrolyte fuel cells. This project was carried out to develop and characterize high performance membrane electrode assemblies (MEAs) for all-solid-state AMFCs. The primary fuel of interests is ethanol, but hydrogen was used in the development stages to facilitate the diagnostic and evaluation of the fuel cell performance. In the preliminary investigation, AMFC was assembled using off-the-shelf electrodes and anion-exchange membrane (AEM). It was found that the performance of AMFC operating on ethanol fuel was limited by a large high-frequency resistance (HFR) value. The advantage of using non-toxic ethanol fuel was also compromised by the need to add hydrazine and potassium hydroxide to the fuel blend. Subsequently, a high performance MEA was developed for an all-solid-state AMFC, in which liquid electrolyte or other additives were not required during the operation of the fuel cell. Ionomer was incorporated in the formulation of catalyst ink, and the catalyst ink was directly coated on the anion-exchange membrane (AEM). An ionomer content of 20 wt.% was found to be the optimum amount required in the catalyst layers. It was demonstrated that the AMFC generated a maximum power density of 365 mW/cm2 and 213 mW/cm 2 with the use of hydrogen/oxygen and hydrogen/pure air, respectively. The performance of the AMFC was also found to be influenced by exposure to carbon dioxide in the air. Hence, the CCMs were pre-treated in potassium hydroxide solution and pure oxygen was used to condition the fuel cell to maximize the power output from the AMFCs. Although satisfactory performance was demonstrated in the AMFC, its stability during cell operation remains a major issue. The poor stability was attributed to degradation of

  15. Multi-column step-gradient chromatography system for automated ion exchange separations

    International Nuclear Information System (INIS)

    A multi-column step-gradient chromatography system has been designed to perform automated sequential separations of radionuclides by ion exchange chromatography. The system consists of a digital programmer with automatic stream selection valve, two peristaltic pumps, ten columns, and a fraction collector. The automation allows complicated separations of radionuclides to be made with minimal analyst attention and allows for increased productivity and reduced cost of analyses. Results are reported for test separations on mixtures of radionuclides by the system

  16. Chapter 5. Uranium extraction technology from mine and drainage waters of uranium industry wastes. 5.5. Uranium extraction from mine and technical waters by anion exchanger A M(p)

    International Nuclear Information System (INIS)

    Present article is devoted to uranium extraction from mine and technical waters by anion exchanger A M(p). The basic process flow diagram of uranium extraction from mine waters (sorbent anion exchanger A M(p)) was proposed.

  17. Human kidney anion exchanger 1 interacts with kinesin family member 3B (KIF3B)

    Energy Technology Data Exchange (ETDEWEB)

    Duangtum, Natapol [Medical Molecular Biology Unit, Office for Research and Development Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Junking, Mutita; Sawasdee, Nunghathai [Medical Molecular Biology Unit, Office for Research and Development Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Cheunsuchon, Boonyarit [Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Limjindaporn, Thawornchai, E-mail: limjindaporn@yahoo.com [Department of Anatomy, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Yenchitsomanus, Pa-thai, E-mail: grpye@mahidol.ac.th [Medical Molecular Biology Unit, Office for Research and Development Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand)

    2011-09-16

    Highlights: {yields} Impaired trafficking of kAE1 causes distal renal tubular acidosis (dRTA). {yields} The interaction between kAE1 and kinesin family member 3B (KIF3B) is reported. {yields} The co-localization between kAE and KIF3B was detected in human kidney tissues. {yields} A marked reduction of kAE1 on the cell membrane was observed when KIF3B was knockdown. {yields} KFI3B plays an important role in trafficking of kAE1 to the plasma membrane. -- Abstract: Impaired trafficking of human kidney anion exchanger 1 (kAE1) to the basolateral membrane of {alpha}-intercalated cells of the kidney collecting duct leads to the defect of the Cl{sup -}/HCO{sub 3}{sup -} exchange and the failure of proton (H{sup +}) secretion at the apical membrane of these cells, causing distal renal tubular acidosis (dRTA). In the sorting process, kAE1 interacts with AP-1 mu1A, a subunit of AP-1A adaptor complex. However, it is not known whether kAE1 interacts with motor proteins in its trafficking process to the plasma membrane or not. We report here that kAE1 interacts with kinesin family member 3B (KIF3B) in kidney cells and a dileucine motif at the carboxyl terminus of kAE1 contributes to this interaction. We have also demonstrated that kAE1 co-localizes with KIF3B in human kidney tissues and the suppression of endogenous KIF3B in HEK293T cells by small interfering RNA (siRNA) decreases membrane localization of kAE1 but increases its intracellular accumulation. All results suggest that KIF3B is involved in the trafficking of kAE1 to the plasma membrane of human kidney {alpha}-intercalated cells.

  18. Human kidney anion exchanger 1 interacts with kinesin family member 3B (KIF3B)

    International Nuclear Information System (INIS)

    Highlights: → Impaired trafficking of kAE1 causes distal renal tubular acidosis (dRTA). → The interaction between kAE1 and kinesin family member 3B (KIF3B) is reported. → The co-localization between kAE and KIF3B was detected in human kidney tissues. → A marked reduction of kAE1 on the cell membrane was observed when KIF3B was knockdown. → KFI3B plays an important role in trafficking of kAE1 to the plasma membrane. -- Abstract: Impaired trafficking of human kidney anion exchanger 1 (kAE1) to the basolateral membrane of α-intercalated cells of the kidney collecting duct leads to the defect of the Cl-/HCO3- exchange and the failure of proton (H+) secretion at the apical membrane of these cells, causing distal renal tubular acidosis (dRTA). In the sorting process, kAE1 interacts with AP-1 mu1A, a subunit of AP-1A adaptor complex. However, it is not known whether kAE1 interacts with motor proteins in its trafficking process to the plasma membrane or not. We report here that kAE1 interacts with kinesin family member 3B (KIF3B) in kidney cells and a dileucine motif at the carboxyl terminus of kAE1 contributes to this interaction. We have also demonstrated that kAE1 co-localizes with KIF3B in human kidney tissues and the suppression of endogenous KIF3B in HEK293T cells by small interfering RNA (siRNA) decreases membrane localization of kAE1 but increases its intracellular accumulation. All results suggest that KIF3B is involved in the trafficking of kAE1 to the plasma membrane of human kidney α-intercalated cells.

  19. Adsorption Properties of Ni(II by D301R Anion Exchange Resin

    Directory of Open Access Journals (Sweden)

    Song Xiuling

    2014-01-01

    Full Text Available The adsorption of Ni(II with D301R resin was investigated in this paper. The results showed that the saturated extent of adsorption Ni(II by the resin was 84.3 mg/g. The equilibrium data of Ni(II sorption was better described by Langmuir isotherm model (r2=0.994 while that of Ni(II sorption also fitted in Freundlich isotherm model within the experimental concentration range. The amount of the constant (q0 of Ni(II under 298 K in Langmuir model was 76.92 mg/g, which was close to the experimental results. The constant n was within 2–10 in Freundlich model; it was shown that adsorption of Ni(II by the resin was easy to take place. The uptake kinetics followed the Lagergren pseudo-first-order rate equation (r2=0.9813. The particle diffusion controlled the adsorption process of Ni(II. The coefficient of the intraparticle diffusion increased with the increase of the pH values and the concentration of Ni(II in aqueous solution. There was a drop of 20.1 cm−1 for the bending vibration frequency of N–H bond. Results showed that the adsorption of Ni(II by D301R anion exchange resin was the surface complexation through the infrared spectrum analysis.

  20. Polyphenylene sulfide based anion exchange fiber: Synthesis, characterization and adsorption of Cr(Ⅵ)

    Institute of Scientific and Technical Information of China (English)

    Jiajia Huang; Xin Zhang; Lingling Bai; Siguo Yuan

    2012-01-01

    A fibrous strong base anion exchanger(QAPPS)was prepared for the first time via chloromethylation and quaternary amination reaction of polyphenylene sulfide fiber(PPS),and its physical-chemical structure and adsorption behavior for Cr(Ⅵ)were characterized by FTIR,Energy Dispersive Spectrometry,TG-DTG,elemental analysis and batch adsorptive technique,respectively.The novel fibrous adsorbent could effectively adsorb Cr(Ⅵ)over the pH range 1-12,the maximum adsorption capacity was 166.39 mg/g at pH 3.5,and the adsorption behavior could be described well by Langrnuir isotherm equation model.The adsorption kinetics was studied using pseudo first-order and pseudo second-order models,and the t1/2 and equilibrium adsorption time were 5 and 20 rain respectively when initial Cr(Ⅵ)concentration was 100 mg/L.The saturated fibers could be regenerated rapidly by a mixed solution of 0.5 mol/L NaOH and 0.5 mol/L NaCl,and the adsorption capacity was well maintained after six adsorption-desorption cycles.

  1. Poly(phenyl sulfone) anion exchange membranes with pyridinium groups for vanadium redox flow battery applications

    Science.gov (United States)

    Zhang, Bengui; Zhang, Enlei; Wang, Guosheng; Yu, Ping; Zhao, Qiuxia; Yao, Fangbo

    2015-05-01

    To develop high performance and cost-effective membranes with low permeability of vanadium ions for vanadium redox flow battery (VRFB) application, poly(phenyl sulfone) anion exchange membranes with pyridinium groups (PyPPSU) are prepared and first investigated for VRFB application. PyPPSU membranes show much lower vanadium ions permeability (0.07 × 10-7-0.15 × 10-7 cm2 min-1) than that of Nafion 117 membrane (31.3 × 10-7 cm2 min-1). As a result, the self-discharge duration of the VRFB cell with PyPPSU membrane (418 h) is about four times longer than that of VRFB cell with Nafion 117 membrane (110 h). Furthermore, the VRFB cell with PyPPSU membrane exhibits higher battery efficiency (coulombic efficiency of 97.8% and energy efficiency of 80.2%) compare with that of VRFB cell with Nafion 117 membrane (coulombic efficiency of 96.1% and energy efficiency of 77.2%) at a high current density of 100 mA cm-2. In addition, PyPPSU membrane exhibits stable performance in 100-cycle test. The results indicate that PyPPSU membrane is high performance and low-cost alternative membrane for VRFB application.

  2. A new method for antimony speciation in plant biomass and nutrient media using anion exchange cartridge.

    Science.gov (United States)

    Tisarum, Rujira; Ren, Jing-Hua; Dong, Xiaoling; Chen, Hao; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    A selective separation method based on anion exchange cartridge was developed to determine antimony (Sb) speciation in biological matrices by graphite furnace atomic absorption spectrophotometry (GFAAS). The selectivity of the cartridge towards antimonite [Sb(III)] and antimonate [Sb(V)] reversed in the presence of deionized (DI) water and 2mM citric acid. While Sb(V) was retained by the cartridge in DI water, Sb(III) was retained in citric acid media. At pH 6, Sb(III) and Sb(V) formed Sb(III)- and Sb(V)-citrate complexes, but the cartridge had higher affinity towards the Sb(III)-citrate complex. Separation of Sb(III) was tested at various concentrations in fresh and spent growth media and plant tissues. Our results showed that cartridge-based Sb speciation was successful in plant tissues, which was confirmed by HPLC-ICP-MS. The cartridge retained Sb(III) and showed 92-104% Sb(V) recovery from arsenic hyperaccumulator Pteris vittata roots treated with Sb(III) and Sb(V). The cartridge procedure is an effective alternative for Sb speciation, offering low cost, reproducible results, and simple Sb analysis using GFAAS. PMID:26452943

  3. Enhanced performance of anion exchange membranes via crosslinking of ion cluster regions for fuel cells

    Science.gov (United States)

    Lai, Ao Nan; Guo, Dong; Lin, Chen Xiao; Zhang, Qiu Gen; Zhu, Ai Mei; Ye, Mei Ling; Liu, Qing Lin

    2016-09-01

    Development of anion exchange membranes (AEMs) with high hydroxide conductivity, good dimensional and alkaline stabilities is still a challenge for the practical application of AEM fuel cells. In this study, we report a new strategy to prepare high-performance AEMs with crosslinked ionic regions. A series of phenolphthalein-containing poly(arylene ether sulfone)s crosslinked AEMs was synthesized by grafting ion groups selectively and densely on the phenolphthalein units to form ion clusters that are further crosslinked to generate the hydrophilic ionic regions. The crosslinking reaction not only improved the dimensional stability of the AEMs, but also increased the aggregation of the ion clusters leading to the formation of hydrophilic/hydrophobic phase-separated morphology and ion-conducting channels. As a result, enhancements in both ion conductivity and dimensional stability can be achieved. The crosslinked AEMs showed high hydroxide conductivities in the range of 52.2-143.4 mS cm-1 from 30 to 80 °C and a superb ratio of relative conductivity to relative swelling at 80 °C. Furthermore, the crosslinked AEMs also exhibited good mechanical properties, thermal and alkaline stabilities and desirable single cell performance. This work presents a promising strategy for the synthesis of high-performance AEMs for fuel cells.

  4. Separation of Fluoride Ions in an Electrolytic Cell by Using an AnionExchange Membrane

    International Nuclear Information System (INIS)

    Separation of fluoride ions in an electrolytic cell with an anionexchange membrane which is so-called an electrodialysis process has beenperformed. The experiment have been taken place in room temperature in anelectrolytic cell made by plexiglas consisted on anode and cathode chambersseparated by an anion exchange membrane in dimension of 4 x 4 cm. The carbonand stainless steel are applied as an anode and platinum as s' cathode. Theanolyte is a HNO3 0.3 M solution, while a solution of NaF 0.3 M, and amixture of NaF 0.3 M containing uranyl nitrate solution for separating offluoride ions and uranium are used as a catholyte. The distance between theelectrode and the membrane is 1.5 cm and this distance is kept constant. Theparameters observed are the current voltage, cathode applied, and uraniumconcentration. For the solution without uranium, the results show that thefluoride ions transferred are around 50 % using carbon as a cathode for 3hours and the voltage of 10 volts, while for SS as a cathode are around 93 %.For the solution containing uranium, the fluoride ions transferred are around78 % for 3.5 hours and the uranium ions remain in the catholyte in which mostof them are as 8 yellow deposit of Na2U2O7 on the cathode surface andothers are as a white precipitate of NaUF5 on the bottom of the cathodechamber. (author)

  5. Fundamental study of practical separation of boron isotopes by means of anion exchange resin, (1)

    International Nuclear Information System (INIS)

    Separation of boron isotopes was carried out using a weak base anion exchange column (in free base form). After boric acid solution was passed through the column, the boric acid band formed on the column was eluted with pure water. The authors discuss the effects on boron isotope separation caused by variations of the concentration of feed solution charged to the column, of the amount of boric acid charged and of the flow rate of feed and eluent solutions. Results were as follows: (1) As the concentration of boric acid charged to the column increased and the amount of boric acid charged became large, the amount of enriched 10B(D sup(γ)) increased. (2) The optimum flow rate was 10 -- 20 ml/cm2.hr. (3) The atomic fraction of 10B in the plateau region of the isotope enrichment curve was nearly 0.190, compared with 0.198 for the feed solution. (4) In cases where the boric acid concentration in the effluent never exceeded 0.3 mol/l, no significant tailling was observed at the end of the chromatographic band. (auth.)

  6. Concentration and separation of vanadium from alkaline media by strong alkaline anion-exchange resin 717

    Institute of Scientific and Technical Information of China (English)

    HUANG Jinwen; SU Peng; WU Wenwei; LIAO Sen; QIN Huiquan; WU Xuehang; HE Xiaohu; TAO Liujia; FAN Yanjin

    2010-01-01

    With strong alkaline anion-exchange resin 717 as the sorbent and NaOH solution as the eluent, a study on the sorption from alkaline solution and elution of vanadium(Ⅴ), silicon(Ⅳ), and aluminium(Ⅲ) was carried out. Different parameters affecting the sorption and elution process,including temperature, pH values as well as the ratio of resin to solution, were investigated. The results show that sorption degree of vanadium(Ⅴ) increases with a decrease of pH values, and V(Ⅴ) ions are easier sorbed than Si(Ⅳ) and Al(Ⅲ) ions under the same conditions. The sorption degree of V(Ⅴ), Si(Ⅳ), and Al(Ⅲ) at pH 9.14 for 15 min are 90.6%, 33.5%, and 21.6%, respectively. Si(Ⅳ), Al(Ⅲ), and V(Ⅴ) ions sorbed on 717 resin were eluted by use of 2 mol.L-1 NaOH solution; the desorption degree of V(Ⅴ), Si(Ⅳ), and Al(Ⅲ) for 5 min are 81.7 %,99.1%, and 99.3%, respectively.

  7. Fixation and separation of the elements thorium and uranium using anion exchange resins in nitrate solution

    International Nuclear Information System (INIS)

    The exchange of thorium and uranium between a strong base anion resin and a mixed water + ethanol solvent containing nitrate ions is studied. It is assumed that in the resin the thorium and uranium are fixed in the form of the complexes Th(NO3)62- and UO2(NO3)42- in solution these elements are present in the form of complexes having the general formula: Th(NO3)6-nn-2 and UO2(NO3)4-nn-2 It has been possible to deduce a law for the changes in the partition functions of thorium and uranium as a function of the concentrations of the various species in solution and of the complexing ion NO3. From this has been deduced the optimum operational conditions for separating a mixture of these two elements. Finally, in these conditions, the influence of a few interfering ions has been studied: Ba, Bi, Ce, La, Mo, Pb, Zr. The method proposed can be used either as a preparation, or for the dosage of thorium by a quantitative separation. (author)

  8. PLUTONIUM LOADING CAPACITY OF REILLEX HPQ ANION EXCHANGE COLUMN - AFS-2 PLUTONIUM FLOWSHEET FOR MOX

    Energy Technology Data Exchange (ETDEWEB)

    Kyser, E.; King, W.; O' Rourke, P.

    2012-07-26

    Radioactive plutonium (Pu) anion exchange column experiments using scaled HB-Line designs were performed to investigate the dependence of column loading performance on the feed composition in the H-Canyon dissolution process for plutonium oxide (PuO{sub 2}) product shipped to the Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). These loading experiments show that a representative feed solution containing {approx}5 g Pu/L can be loaded onto Reillex{trademark} HPQ resin from solutions containing 8 M total nitrate and 0.1 M KF provided that the F is complexed with Al to an [Al]/[F] molar ratio range of 1.5-2.0. Lower concentrations of total nitrate and [Al]/[F] molar ratios may still have acceptable performance but were not tested in this study. Loading and washing Pu losses should be relatively low (<1%) for resin loading of up to 60 g Pu/L. Loading above 60 g Pu/L resin is possible, but Pu wash losses will increase such that 10-20% of the additional Pu fed may not be retained by the resin as the resin loading approaches 80 g Pu/L resin.

  9. Separation of rare earth elements using Ln-EDTA eluent in an anion exchanger

    International Nuclear Information System (INIS)

    Chloride form anion exchange resin was used to separate one of the elements from the rare earth mixture using respectable Ln-EDTA eluent. Sm3+, La3+ or Ce4+ complexed with EDTA was passed through the resin column and eluted with an Sm-EDTA solution as an eluent. Here all the rare earth element ions except Sm3+ were passed. Adsorbed Sm3+ in resin was eluted with 1.0 M HCl solution. If La-EDTA solution as an eluent was used to separate lanthanum ions, lanthanum ions were eluted together with other rare earth elements. When Ce-EDTA solution was also used for separation of Ce4+, it was eluted in the region of other rare earth elements. In the case of Sm-EDTA elution, the elution mechanism was as follows: Absorption: RCl + Ln-Y- ↔ RLnY + Cl-, Sm-EDTA elution: RLnY + Sm-Y- ↔ RSmY + Ln-Y-, HCl elution: RSmY + HCl ↔ RCl + Sm-Y-. (author)

  10. Influence of Hydration Level on Polymer and Water Dynamics in Alkaline Anion Exchange Fuel Cell Membranes

    Science.gov (United States)

    Tarver, Jacob; Kim, Jenny; Tyagi, Madhu; Soles, Christopher; Tsai, Tsung-Han; Coughlin, Bryan

    2015-03-01

    Triblock copolymers based on poly(chloromethylstyrene)-b-poly(ethylene)-b-poly(chloromethylstyrene) can be quaternized to different extents to yield anion exchange membranes for alkaline fuel cells. In the absence of moisture, these membranes demonstrate bilayer lamellar morphology. Upon high levels of hydration, however, in-situ small angle neutron scattering reveals the emergence of higher-order diffraction peaks. This phenomena has previously been observed in analogous diblock copolymer-based membranes and has been attributed to the induction of a multilayer lamellar morphology in which selective striping of water occurs in the center of the ion-rich domain. By conducting humidity-resolved quasielastic neutron scattering (QENS) measurements using deuterated water, we are able to isolate differences in the pico- to nanosecond timescale dynamics of the hydrogenated membrane upon hydration. QENS measurements in the presence of a hydrogenated water source subsequently permit deconvolution and isolation of the translational and rotational dynamics of water as a function of relative humidity, revealing spatial and temporal changes in polymer and water motion at high levels of hydration.

  11. Selective Anion Exchange Resins for the Removal of Perchlorate [(CIO{sub 4}{sup -})] from Groundwater

    Energy Technology Data Exchange (ETDEWEB)

    Gu, B.

    1999-05-20

    The primary objective of this project was to evaluate a novel bifunctional anion exchange resin for the cost-effective, in situ treatment of groundwater contaminated with perchlorate (ClO{sub 4}{sup -}). Both laboratory and field studies were performed to determine the selectivity and capacity of the bifunctional synthetic resins to sorb ClO{sub 4}{sup -} from simulated or actual contaminated groundwater. A number of synthetic bifunctional resins, including two commercial versions made by Purolite International and three commercially available, mono-functional resins, were tested. Initial laboratory batch and column breakthrough studies determined the best synthetic resins and the optimal conditions for the field experiment. Laboratory results indicated that the bifunctional synthetic resins, D-3696 and RO-02-119 were highly selective toward ClO{sub 4}{sup -} and performed {approx}5 times better than the best commercial nitrate resin (Purolite{reg_sign} A-520E) and more than an order of magnitude better than some nonselective commercial resins (e.g. Amberlite{reg_sign} IRA-900). The bifunctional resins were particularly effective in removing trace quantities of ClO{sub 4}{sup -} in groundwater to below the detection limit ({approx} 3 {micro}g/L). A field trial demonstrated that the bifunctional resin (D-3696) was able to treat {approx} 110,000 bed volumes of groundwater before a 10% breakthrough of ClO{sub 4}{sup -} occurred under the column flow-through conditions (running at {approx} 2 bed volumes per minute). On the other hand, the Purolite{reg_sign} A-520E resin was able to treat {approx} 23,000 bed volumes of groundwater under the same experimental conditions. No pretreatment was needed to remove either dissolved organic matter or other competing anions (such as SO{sub 4}{sup 2-} or NO{sub 3}{sup -}) in the groundwater, and the treatment process did not alter the water quality by removing or adding secondary by-products because of the high selectivity of the

  12. Conservation of order, disorder, and "crystallinity" during anion-exchange reactions among layered double hydroxides (LDHs) of Zn with Al.

    Science.gov (United States)

    Radha, A V; Kamath, P Vishnu; Shivakumara, C

    2007-04-01

    Carbonate and chloride ions mediate an ordered stacking of metal hydroxide slabs to yield ordered layered double hydroxides (LDHs) of Zn with Al, by virtue of their ability to occupy crystallographically well-defined interlayer sites. Other anions such as ClO(4)- (T(d)), BrO(3)- (C(3v)), and NO(3)- (coordination symmetry C(2v)) whose symmetry does not match the symmetry of the interlayer sites (D(3h) or O(h)) introduce a significant number of stacking faults, leading to turbostratic disorder. SO(4)(2-) ions (coordination symmetry C(3v)) alter the long-range stacking of the metal hydroxide slabs to nucleate a different polytype. The degree of disorder is also affected by the method of synthesis. Anion-exchange reactions yield a solid with a greater degree of order if the incoming ion is a CO3(2-) or Cl-. Incoming NO(3)- ions yield an interstratified phase, whereas incoming SO(4)(2-) ions generate turbostratic disorder. Conservation or its converse, elimination, of stacking disorders during anion exchange is the net result of several competing factors such as (i) the orientation of the hydroxyl groups in the interlayer region, (ii) the symmetry of the interlayer sites, (iii) the symmetry of the incoming ion, and (iv) the configuration of the anion. These short-range interactions ultimately affect the long-range stacking order or "crystallinity" of the LDH. PMID:17388484

  13. THERMODYNAMIC STUDY ON ADSORPTION OF AROMATIC SULFONIC ACIDS ONTO MACROPOROUS WEAK BASE ANION EXCHANGER FROM AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    Chao Long; Quan-xing Zhang; Ai-min Li; Jin-long Chen

    2004-01-01

    The adsorption equilibrium isotherms of three aromatic sulfonic acid compounds, 2-naphthalenesulfonic acid, ptoluenesulfonic acid and p-chlorobenzenesulfonic acid, from aqueous solutions by macroporous weak base anion exchanger within the temperature range of 293 K-313 K were obtained. Several isotherm equations were correlated with the equilibrium data, and the experimental data was found to fit the three-parameter Redlich-Peterson equation best within the entire range of concentrations. The study showed that the hydrophobicity of solute has distinct influence on adsorption capacity of the anion exchanger for the aromatic sulfonic acid. Moreover, estimations of the isosteric enthalpy, free energy,and entropy change of adsorption were also reported. The positive isosteric enthalpy and entropy change for adsorption indicate an endothermic and entropy driven process in the present study.

  14. An Anion-Exchange Method for the Separation of P-32 Activity in Neutron-Irradiated Biological Material

    International Nuclear Information System (INIS)

    Strong hydrochloric-acid solutions containing small amounts of orthophosphoric and citric acid and radioactive tracers of the elements Na, P, K, Ca, Se, Cr, Mn, Ni, Rb, Sr, Cs, Ba, La, and Ce were titrated with a water suspension of strongly basic anion-exchange resin in the hydroxide form. The titration was carried out to pH = 3.0. It was followed by filtration of the mixture on the top of a small anion-exchange column in the chloride form and a final washing with water. Phosphorus was quantitatively adsorbed by the resin and the scandium retention was better than 96 per cent. The remaining elements passed quantitatively into the effluent, with the exception of nickel, which was adsorbed to a very small extent

  15. An investigation of the sorption/desorption of organics from natural waters by solid adsorbents and anion exchangers

    International Nuclear Information System (INIS)

    The results of laboratory and operational tests at thermal and nuclear power stations on anion exchangers and solid adsorbents of makeup water treatment plants with regard to the sorption/desorption of organic substances in natural water and condensate are presented. The resins Amberlite trademark IRA-67, IRA-900, IRA-958Cl, Purolite registered 2 A-500P, DowexTM3 Marathon, and others were tested. Retention of up to 60-80% of the ''organic'' material on the anion exchangers and organic absorbers installed at different places in the technological scheme of the water processing unit was attained. The possibility of a partial ''poisoning'' of the resins and the degradation of the working characteristics over the first year of operation are discussed. (orig.)

  16. Subzero temperature chromatography for reduced back-exchange and improved dynamic range in amide hydrogen/deuterium exchange mass spectrometry.

    Science.gov (United States)

    Venable, John D; Okach, Linda; Agarwalla, Sanjay; Brock, Ansgar

    2012-11-01

    Amide hydrogen/deuterium exchange is a commonly used technique for studying the dynamics of proteins and their interactions with other proteins or ligands. When coupled with liquid chromatography and mass spectrometry, hydrogen/deuterium exchange provides several unique advantages over other structural characterization techniques including very high sensitivity, the ability to analyze proteins in complex environments, and a large mass range. A fundamental limitation of the technique arises from the loss of the deuterium label (back-exchange) during the course of the analysis. A method to limit loss of the label during the separation stage of the analysis using subzero temperature reversed-phase chromatography is presented. The approach is facilitated by the use of buffer modifiers that prevent freezing. We evaluated ethylene glycol, dimethyl formamide, formamide, and methanol for their freezing point suppression capabilities, effects on peptide retention, and their compatibilities with electrospray ionization. Ethylene glycol was used extensively because of its good electrospray ionization compatibility; however, formamide has potential to be a superior modifier if detrimental effects on ionization can be overcome. It is demonstrated using suitable buffer modifiers that separations can be performed at temperatures as low as -30 °C with negligible loss of the deuterium label, even during long chromatographic separations. The reduction in back-exchange is shown to increase the dynamic range of hydrogen/deuterium exchange mass spectrometry in terms of mixture complexity and the magnitude with which changes in deuteration level can be quantified. PMID:23025328

  17. Anion- or Cation-Exchange Membranes for NaBH4/H2O2 Fuel Cells?

    Science.gov (United States)

    Sljukić, Biljana; Morais, Ana L; Santos, Diogo M F; Sequeira, César A C

    2012-01-01

    Direct borohydride fuel cells (DBFC), which operate on sodium borohydride (NaBH4) as the fuel, and hydrogen peroxide (H2O2) as the oxidant, are receiving increasing attention. This is due to their promising use as power sources for space and underwater applications, where air is not available and gas storage poses obvious problems. One key factor to improve the performance of DBFCs concerns the type of separator used. Both anion- and cation-exchange membranes may be considered as potential separators for DBFC. In the present paper, the effect of the membrane type on the performance of laboratory NaBH4/H2O2 fuel cells using Pt electrodes is studied at room temperature. Two commercial ion-exchange membranes from Membranes International Inc., an anion-exchange membrane (AMI-7001S) and a cation-exchange membrane (CMI-7000S), are tested as ionic separators for the DBFC. The membranes are compared directly by the observation and analysis of the corresponding DBFC's performance. Cell polarization, power density, stability, and durability tests are used in the membranes' evaluation. Energy densities and specific capacities are estimated. Most tests conducted, clearly indicate a superior performance of the cation-exchange membranes over the anion-exchange membrane. The two membranes are also compared with several other previously tested commercial membranes. For long term cell operation, these membranes seem to outperform the stability of the benchmark Nafion membranes but further studies are still required to improve their instantaneous power load. PMID:24958292

  18. Optimizing the performance of a membrane bio-electrochemical reactor using an anion exchange membrane for wastewater treatment

    OpenAIRE

    Jian LI; He, Zhen

    2015-01-01

    A membrane bioelectrochemical reactor (MBER) is a system integrating ultrafiltration membranes into microbial fuel cells (MFCs) for energy-efficient wastewater treatment. To improve nitrogen removal, an MBER based on an anion exchange membrane (AEM), the MBER-A, was investigated for treating synthetic solution or actual wastewater during a 200-day operation. The MBER-A significantly improved the removal of total nitrogen to 56.9% with the synthetic solution, compared with 7.6% achieved in the...

  19. Synthesis of blue-photoluminescent graphene quantum dots/polystyrenic anion-exchange resin for Fe(III) detection

    Science.gov (United States)

    Zhang, Wenjun; Gan, Jie

    2016-05-01

    A novel solid fluorescent sensor with millimeter size, based on graphene quantum dots/polystyrenic anion-exchange resin (GQDs/PS-AER) was obtained for the detection of Fe3+. The linear response range of Fe3+ was obtained from 1 μM to 7 μM and the detection limit was as low as 0.65 μM. In addition, the sensor could be regenerated by adding complexing agent EDTA and be separated by using simple filtration.

  20. Nondestructive radio isotopic technique for performance evaluation of industrial grade anion exchange resins Amberlite IRN78 and Indion NSSR

    International Nuclear Information System (INIS)

    The present study deals with the application of radiotracers 131I and 82Br as a non-destructive tool to evaluate the performance of Amberlite IRN78 (nuclear grade) and Indion NSSR (non-nuclear grade) anion exchange resins. In general based on radiotracer applications it was observed that Amberlite IRN78 resins show superior performance over Indion NSSR resins under identical operational parameters.

  1. Sulfuric Acid and Ammonia Generation by Bipolar Membranes Electrodialysis: Transport Rate Model for Ion and Water through Anion Exchange Membrane

    OpenAIRE

    Zhang, Xiaoyan; Lu, Wenhua; Ren, HongYan; Cong, Wei

    2008-01-01

    Regeneration of sulfuric acid and ammonia from ammonium sulfate by bipolar membrane electrodialysis (BMED) coupling with stripping ammonia by air-blowing was studied. The result showed that it was feasible to regenerate sulfuric acid and ammonia from ammonium sulfate solution using this method. Empirical models to describe the ion and water transport behaviors through anion exchange membrane for BMED system were successfully developed. The models were valid to evaluate water transport rate an...

  2. Nondestructive radio isotopic technique for performance evaluation of industrial grade anion exchange resins Amberlite IRN78 and Indion NSSR

    Energy Technology Data Exchange (ETDEWEB)

    Singare, Pravin U. [Bhavan' s College, Mumbai (India). Dept. of Chemistry

    2016-01-15

    The present study deals with the application of radiotracers 131I and 82Br as a non-destructive tool to evaluate the performance of Amberlite IRN78 (nuclear grade) and Indion NSSR (non-nuclear grade) anion exchange resins. In general based on radiotracer applications it was observed that Amberlite IRN78 resins show superior performance over Indion NSSR resins under identical operational parameters.

  3. Comparing and Optimizing Nitrate Adsorption from Aqueous Solution Using Fe/Pt Bimetallic Nanoparticles and Anion Exchange Resins

    OpenAIRE

    Muhammad Daud; Zahiruddin Khan; Aisha Ashgar; M. Ihsan Danish; Ishtiaq A. Qazi

    2015-01-01

    This research work was carried out for the removal of nitrate from raw water for a drinking water supply. Nitrate is a widespread ground water contaminant. Methodology employed in this study included adsorption on metal based nanoparticles and ion exchange using anionic resins. Fe/Pt bimetallic nanoparticles were prepared in the laboratory, by the reduction of their respective salts using sodium borohydride. Scanning electron microscope, X-ray diffraction, energy dispersive spectrometry, and ...

  4. Separation of boron isotopes by ion exchange chromatography: studies with Duolite-162, a type-II resin

    International Nuclear Information System (INIS)

    The selection of resin plays an important role in the process of separation of boron isotopes by ion exchange chromatography. The determination of (i) ion exchange capacity of Duolite-162 resin for hydroxyl - chloride exchange, (ii) hydroxyl - borate exchange, (iii) isotopic exchange separation factor by batch method and (iv) effect of concentration of boric acid on isotopic exchange separation factor to test the suitability of the above resin for this process are discussed in this report. (author)

  5. Recovery of platinum, tin and indium from spent catalysts in chloride medium using strong basic anion exchange resins

    International Nuclear Information System (INIS)

    Highlights: → Platinum, tin and indium recoveries from spent reforming catalysts. → Adsorption of metal chlorocomplexes on strongly basic anion-exchange resins. → Sequential desorption via elution with reducing (Pt, Sn) or complexing (In) agents. → The elements were recovered in very high yields. → The anion-exchange resins can be reused. - Abstract: This work describes a route for platinum recovery from spent commercial Pt and PtSnIn/Al2O3 catalysts using strong basic mesoporous and macroporous anion exchange resins (Cl- form). The catalysts were leached with aqua regia (75 oC, 20-25 min). Platinum adsorption was influenced by the presence of other metals which form chlorocomplexes (tin, indium) and also base metals (aluminum). However, it was possible to overcome this fact by a sequential desorption procedure. Aluminum was selectively removed from the resins by elution with 3 mol L-1 HCl. Platinum was desorbed passing 1 mol L-1 Na2S2O3 (pH 9). Tin was removed by elution with 0.1 mol L-1 ascorbic acid. Indium was removed using 0.1 mol L-1 EDTA as eluent. Desorption efficiency exceeded 99% for all metals. Metals were recovered in high yields (>98 wt%).

  6. THE EFFECT OF IONIC STRENGTH ON THE UPTAKE OF TAURINE ON A STRONG-BASIC ANION EXCHANGE RESIN

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Studied the effect of ionic strength on the uptake of taurine on a strong-basic anionexchange resin. The batch phase equilibrium experiments of ta urine on the anion exchange resin D290 were conducted at different ionic strength, and then the amounts of uptake of taurine on the resin at different pH were determined. The ion exchange mechanisms of taurine on the anion exchange resin at different pH were discussed. Experimental results showed that with increase of the ionic strength of solution, the adsorbed amount of taurine on the resin D290 decreased; Adding small amounts of NaOH or HCl into the system of taurine aqueous solution/D290 anionresin would make the amount of taurine taken up on the resin to decrease due to the competition uptakes of hydroxyl ion with taurine or the decrease in the amount of absorbable zwitterions of taurine in the solution and excluding the cations of taurine from the anion resin.

  7. Selenium speciation in pretreated human urine by ion-exchange chromatography and ICP-MS detection

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Jons, O.; Bendahl, L.

    2001-01-01

    Urine samples were extracted by benzo-15-crown-5-ether to remove sodium and potassium. More than 90% of the sodium and potassium content of the urine was removed with this extraction. In a cation-exchange system based on oxalic acid at pH 3, chromatography of an untreated urine pool resulted in a...

  8. Deletion of the anion exchanger Slc26a4 (pendrin) decreases apical Cl−/HCO3− exchanger activity and impairs bicarbonate secretion in kidney collecting duct

    OpenAIRE

    Amlal, Hassane; Petrovic, Snezana; Xu, Jie; Wang, Zhaohui; Sun, Xuming; Barone, Sharon; Soleimani, Manoocher

    2010-01-01

    The anion exchanger Pendrin, which is encoded by SLC26A4 (human)/Slc26a4 (mouse) gene, is localized on the apical membrane of non-acid-secreting intercalated (IC) cells in the kidney cortical collecting duct (CCD). To examine its role in the mediation of bicarbonate secretion in vivo and the apical Cl−/HCO3− exchanger in the kidney CCD, mice with genetic deletion of pendrin were generated. The mutant mice show the complete absence of pendrin expression in their kidneys as assessed by Northern...

  9. Quaternized dimethylaminoethyl methacrylate strong base anion exchange fibers for As(V) adsorption

    International Nuclear Information System (INIS)

    N,N-Dimethylaminoethyl methacrylate (DMAEMA) grafted polyethylene/polypropylene (PE/PP) nonwoven fibers (DMAEMA-g-PE/PP) was prepared by radiation-induced graft polymerization. DMAEMA graft chains on nonwoven fibers were quaternized with dimethyl sulfate solution for the preparation of strong base anion exchange fibers (QDMAEMA-g-PE/PP). Fiber structures were characterized by FTIR, XPS and SEM techniques. The effect of solution pH, contact time, initial As(V) ion concentration and coexisting ions on the As(V) adsorption capacity of the QDMAEMA-g-PE/PP fibers were investigated by performing batch adsorption experiments. The adsorption of As(V) by QDMAEMA-g-PE/PP fibers was found to be independent on solution pH in the range 4.00–10.00. Kinetic experiments show that the As(V) adsorption rate was rapid and As(V) adsorption follows pseudo second-order kinetic model. As(V) adsorption equilibrium data were analyzed using Langmuir and Freundlich adsorption isotherm model equations. Langmuir and Freundlich adsorption isotherm models fitted the experimental data well. The maximum adsorption capacity (qmax) calculated from Langmuir isotherm was found to be 83.33 mg As(V)/g polymer at pH 7.00. The adsorbent was used for three cycles without significant loss of adsorption capacity. The adsorbed As(V) ions were desorbed effectively by a 0.1 M NaOH solution. - Highlights: • QDMAEMA-g-PE/PP fibers have high adsorption capacity for As(V) ions. • Adsorption of As(V) is independent on the solution pH over a wide range (4−10). • As(V) adsorption rate of QDMAEMA-g-PE/PP fibers is considerably fast. • The maximum adsorption capacity (qmax) was found to be 83.33 mg As(V)/g polymer

  10. HB-LINE ANION EXCHANGE PURIFICATION OF AFS-2 PLUTONIUM FOR MOX

    Energy Technology Data Exchange (ETDEWEB)

    Kyser, E. A.; King, W. D.

    2012-07-31

    Non-radioactive cerium (Ce) and radioactive plutonium (Pu) anion exchange column experiments using scaled HB-Line designs were performed to investigate the feasibility of using either gadolinium nitrate (Gd) or boric acid (B as H{sub 3}BO{sub 3}) as a neutron poison in the H-Canyon dissolution process. Expected typical concentrations of probable impurities were tested and the removal of these impurities by a decontamination wash was measured. Impurity concentrations are compared to two specifications - designated as Column A or Column B (most restrictive) - proposed for plutonium oxide (PuO{sub 2}) product shipped to the Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). Use of Gd as a neutron poison requires a larger volume of wash for the proposed Column A specification. Since boron (B) has a higher proposed specification and is more easily removed by washing, it appears to be the better candidate for use in the H-Canyon dissolution process. Some difficulty was observed in achieving the Column A specification due to the limited effectiveness that the wash step has in removing the residual B after ~4 BV's wash. However a combination of the experimental 10 BV's wash results and a calculated DF from the oxalate precipitation process yields an overall DF sufficient to meet the Column A specification. For those impurities (other than B) not removed by 10 BV's of wash, the impurity is either not expected to be present in the feedstock or process, or recommendations have been provided for improvement in the analytical detection/method or validation of calculated results. In summary, boron is recommended as the appropriate neutron poison for H-Canyon dissolution and impurities are expected to meet the Column A specification limits for oxide production in HB-Line.

  11. HB-LINE ANION EXCHANGE PURIFICATION OF AFS-2 PLUTONIUM FOR MOX

    Energy Technology Data Exchange (ETDEWEB)

    Kyser, E.; King, W.

    2012-04-25

    Non-radioactive cerium (Ce) and radioactive plutonium (Pu) anion exchange column experiments using scaled HB-Line designs were performed to investigate the feasibility of using either gadolinium nitrate (Gd) or boric acid (B as H{sub 3}BO{sub 3}) as a neutron poison in the H-Canyon dissolution process. Expected typical concentrations of probable impurities were tested and the removal of these impurities by a decontamination wash was measured. Impurity concentrations are compared to two specifications - designated as Column A or Column B (most restrictive) - proposed for plutonium oxide (PuO{sub 2}) product shipped to the Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). Use of Gd as a neutron poison requires a larger volume of wash for the proposed Column A specification. Since boron (B) has a higher proposed specification and is more easily removed by washing, it appears to be the better candidate for use in the H-Canyon dissolution process. Some difficulty was observed in achieving the Column A specification due to the limited effectiveness that the wash step has in removing the residual B after {approx}4 BV's wash. However a combination of the experimental 10 BV's wash results and a calculated DF from the oxalate precipitation process yields an overall DF sufficient to meet the Column A specification. For those impurities (other than B) not removed by 10 BV's of wash, the impurity is either not expected to be present in the feedstock or process, or recommendations have been provided for improvement in the analytical detection/method or validation of calculated results. In summary, boron is recommended as the appropriate neutron poison for H-Canyon dissolution and impurities are expected to meet the Column A specification limits for oxide production in HB-Line.

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

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Hansen, Sven Hedegaard

    1992-01-01

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

  13. Radiotracer application for characterization of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC

    Energy Technology Data Exchange (ETDEWEB)

    Singare, P.U. [Bhavan' s College, Mumbai (India). Dept. of Chemistry

    2015-12-15

    Radio isotopic tracer technique as one of the versatile nondestructive technique is employed to evaluate the performance of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC. The evaluation was made on the basis of ion-isotopic exchange reaction kinetics by using {sup 131}I and {sup 82}Br radioactive tracer isotopes. It was observed that for both the resins, the values of specific reaction rate (min{sup -1}), amount of ion exchanged (mmol) and initial rate of ion exchange (mmol/min) were calculated to be lower for bromide ion-isotopic exchange reaction than that for iodide ion-isotopic exchange reaction. It was observed that for iodide ion-isotopic exchange reaction under identical experimental conditions of 30.0 C, 1.000 g of ion exchange resins and 0.001 mol/L labeled iodide ion solution, the values of specific reaction rate (min{sup -1}), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log K{sub d} were calculated as 0.377, 0.212, 0.080 and 15.5 respectively for Dowex SBR LC resin, which was higher than 0.215, 0.144, 0.031 and 14.1 respectively as that obtained for Tulsion A23 resins. Also at a constant temperature of 30.0 C, as the concentration of labeled iodide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of iodide ions exchanged increases from 84.75 % to 90.20 % for Dowex SBR LC resins which was higher than increases from 57.66 % to 62.38 % obtained for Tulsion A23 resins. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate superior performance of Dowex SBR LC over Tulsion A23 resins under identical experimental conditions.

  14. Radiotracer application for characterization of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC

    International Nuclear Information System (INIS)

    Radio isotopic tracer technique as one of the versatile nondestructive technique is employed to evaluate the performance of nuclear grade anion exchange resins Tulsion A-23 and Dowex SBR LC. The evaluation was made on the basis of ion-isotopic exchange reaction kinetics by using 131I and 82Br radioactive tracer isotopes. It was observed that for both the resins, the values of specific reaction rate (min-1), amount of ion exchanged (mmol) and initial rate of ion exchange (mmol/min) were calculated to be lower for bromide ion-isotopic exchange reaction than that for iodide ion-isotopic exchange reaction. It was observed that for iodide ion-isotopic exchange reaction under identical experimental conditions of 30.0 C, 1.000 g of ion exchange resins and 0.001 mol/L labeled iodide ion solution, the values of specific reaction rate (min-1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were calculated as 0.377, 0.212, 0.080 and 15.5 respectively for Dowex SBR LC resin, which was higher than 0.215, 0.144, 0.031 and 14.1 respectively as that obtained for Tulsion A23 resins. Also at a constant temperature of 30.0 C, as the concentration of labeled iodide ion solution increases from 0.001 mol/L to 0.004 mol/L, the percentage of iodide ions exchanged increases from 84.75 % to 90.20 % for Dowex SBR LC resins which was higher than increases from 57.66 % to 62.38 % obtained for Tulsion A23 resins. The identical trend was observed for the two resins during bromide ion-isotopic exchange reaction. The overall results indicate superior performance of Dowex SBR LC over Tulsion A23 resins under identical experimental conditions.

  15. Ra/Ca separation by ion exchange chromatography

    International Nuclear Information System (INIS)

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

  16. Effect of alcohols on separation behavior of rare earth elements using benzimidazole-type anion-exchange resin in nitric acid solutions

    International Nuclear Information System (INIS)

    Chromatographic separation experiments of trivalent rare earth elements were performed using benzimidazole type anion-exchange resin in nitric/alcohol mixed solvent systems at room temperature. As a result, it was found those trivalent rare earth elements are able to be separated mutually in a 20% HNO3 and 80% MeOH mixed solvent. Based on these results, we systematically examined using various alcohols to make clear the role of alcohols in anion-exchange reactions at various temperatures. (author)

  17. Characterization of synthetic dyes by comprehensive two-dimensional liquid chromatography combining ion-exchange chromatography and fast ion-pair reversed-phase chromatography.

    Science.gov (United States)

    Pirok, Bob W J; Knip, Jitske; van Bommel, Maarten R; Schoenmakers, Peter J

    2016-03-01

    In the late 19th century, newly invented synthetic dyes rapidly replaced the natural dyes on the market. The characterization of mixtures of these so-called early synthetic dyes is complicated through the occurrence of many impurities and degradation products. Conventional one-dimensional liquid chromatography does not suffice to obtain fingerprints with sufficient resolution and baseline integrity. Comprehensive two-dimensional liquid chromatography (LC×LC) is employed in this study, with ion-exchange chromatography in the first dimension and fast ion-pair liquid chromatography in the second. Retention in the first dimension is largely determined by the number of charges, while the selection of a small ion-pair reagent (tetramethylammonium hydroxide) in the second dimension causes retention to be largely determined by the molecular structure of the dye. As a result, there is a high degree of orthogonality of the two dimensions, similar to the values typically encountered in GC×GC. The proposed LC×LC method shows a theroretical peak capacity of about 2000 in an analysis time of about three hours. Clear, informative fingerprints are obtained that open a way to a more efficient characterization of dyes used in objects of cultural heritage. PMID:26868445

  18. Increased selectivity for planar chromatography by ion exchange : cation chromatography on papers impregnated with titanium (IV) based inorganic ion exchangers in DMSO-HNO3 mobile phases

    International Nuclear Information System (INIS)

    Planar chromatography of thirty six metal ions on titanium(IV) phosphate, titanium(IV) tungstate and titanium(IV) molybdate impregnated papers in DMSO-HNO3 mobile phases has been carried out. The ion-exchange capacity of papers is determined and the effects of solvent composition, impregnation and pH on RF values are studied. For K+, Rb+ and Cs+, RF = KC1/2, where C is the nitric acid concentration. The movement of ions is explained on the basis of ion-exchange, adsorption and precipitation. Alberti and Torracca's view for the prediction of elution sequence from RF values has been checked. The sequence of adsorption of ions follows the order : titanium(IV) molybdate > titanium(IV) tungstate > titanium(IV) phosphate. Some of the analytically important separations are reported. (author)

  19. Understanding ion and solvent transport in anion exchange membranes under humidified conditions

    Science.gov (United States)

    Sarode, Himanshu

    Anion exchange membranes (AEM) have been studied for more than a decade for potential applications in low temperature fuel cells and other electrochemical devices. They offer the advantage of faster reaction kinetics under alkaline conditions and ability to perform without costly platinum catalyst. Inherently slow diffusion of hydroxide ions compared to protons is a primary reason for synthesizing and studying the ion transport properties in AEMs. The aim of this thesis is to understand ion transport in novel AEMs using Pulse Gradient stimulated Spin Echo Nuclear Magnetic Resonance technique (PGSE NMR), water uptake, ionic conductivity, Small Angle X-ray Scattering (SAXS) etc. All experiments were performed under humidified conditions (80--95% relative humidity) and fuel cell operating temperatures of 30--90°C. In this work, the NMR tube design was modified for humidifying the entire NMR tube evenly from our previous design. We have developed a new protocol for replacing caustic hydroxide with harmless fluoride or bicarbonate ions for 19F and 13 C NMR diffusion experiments. After performing these NMR experiments, we have obtained in-depth understanding of the morphology linked ion transport in AEMs. We have obtained the highest fluoride self-diffusion coefficient of > 1 x 10-5 cm2/sec ( 55°C) for ETFE-g-PVBTMA membrane which is a result of low tortuosity of 1 obtained for the membrane. This faster fluoride transport combined with low tortuosity of the membrane resulted in > 100mS/cm hydroxide conductivity for the membrane. Polycyclooctene (PCOE) based triblock copolymers are also studied for in-depth understanding of molecular weight, IEC, mechanical and transport properties. Effect of melting temperature of PCOE has favorable effect on increasing ion conductivity and lowering activation energy. Mechanical properties of these types of membranes were studied showing detrimental effect of water plasticization which results in unsuitable mechanical properties

  20. Anion exchange removal of Al3+ from Li+-Al3+ aqueous solution (originating from lithium recovery from brine

    Directory of Open Access Journals (Sweden)

    Anissa Somrani

    2014-06-01

    Full Text Available The purpose of this study is to separate aluminum(III ion from an aqueous solution containing Li+ at 25°C. Al3+ was transferred into [Al(C2O43]3- by means of complexation and removed by an anion exchange resin. This resin was anionic type Amberlite IRA 402 regenerated by sodium chloride. Hence, a theoretical study based on speciation diagrams was carried out to determine the best pH domain for separation. The complexation of aluminum ions by ammonium oxalate was studied. The motar ratio of Ox/Al and pH was investigated. Optimum values of these factors were found to be 3 and 4 respectively. In this case, the remaining lithium is 98.5%.

  1. Behavior of cationic, anionic and colloidal species of titanium, zirconium and thorium in presence of ion exchange resins

    International Nuclear Information System (INIS)

    The distribution of titanium, zirconium and thorium is aqueous and resin phases has been studied using strong cationic resin in the R-NH4 form. Solutions of the above elements in perchloric, nitric, hydrochloric and suphuric media were used. Each set of experiments was made by separately varying one of the five parameters - type of anion present, acidity of solution, temperature of percolation, age of solution and concentration of the element. It was found that, depending on the particular balance of these parameters, the elements investigated may be found in acidic solutions either as cationic, anionic or colloidal species. It is emphasized that the colloidal species of titanium, zirconium or thorium are not retained by the ion exchangers, and from this property a method for the separation and purification of the above elements has been outlined

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

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Hansen, Sven Hedegaard

    Arsenite, arsenate, monomethylarsonate, dimethylarsinate, arsenobetaine, arsenocholine and the tetramethylarsonium ion were subjected to ion-exchange and ion-pair reversed phase HPLC. The ion exchange method was superior in selectivity and time of analysis for the arsenic anions. The ammonium ion...

  3. Purification of drinking water from radioactive contamination by final consumers by means of combined cation and anion exchangers

    International Nuclear Information System (INIS)

    It should be tried to develop an apparatus which makes it possible for the final consumer to purify the drinking water himself in the case of a radioactive contamination of the water. After thorough preliminary studies the most suitable kinds of exchange resins and the best arrangement for a combined cation and anion exchange resins and the best arrangement for a combined cation and anion exchange equipment were determined in inactive preliminary tests. Subsequent the useful capacity (NK) and the purifying factor (RF) were determined for the fission products 90Sr, 131I and 137Cs. The results were for 90Sr: NK = 30 1/2 x 0.5 l resin, RF >= 4.102, for 131I: NK = 32 1/2 x 0.5 l resin, RF = 3.7.102 and for 137Cs: NK > 35 1/2 x 0.5 l resin, RF >= 103. With 2 x 1 l resin the concentration of possible fission products in water can be reduced by 2 orders of magnitude ore more. A proposal for the construction of a household decontamination equipment for drinking water is made. The cost of production will be about A.S. 400,-- to 600,--. (author)

  4. Automated analysis of alditols by anion-exchange chromatography with photometric and fluorimetric postcolumn derivatization.

    Science.gov (United States)

    Honda, S; Takahashi, M; Shimada, S; Kakehi, K; Ganno, S

    1983-02-01

    Eight alditols were separated in ca. 80 min as their borate complexes by stepwise elution with three borate buffers on a column packed with Hitachi 2633 resin. The alditols in the eluate were derivatized automatically to colored, fluorescent products by applying sequential reactions of periodate oxidation and Hantzsch condensation, and the products were detected either photometrically or fluorimetrically. This automated method allowed simultaneous determination of 20-500 and 20-200 nmol amounts of alditols by photometric and fluorimetric monitorings, respectively. The lower limits of detection were ca. 2 and 0.5 nmol, respectively. The interference by aldoses was slight. Aldoses may be also determined as alditols by direct injection of aqueous solutions to which excess amounts of sodium borohydride have been added. This method was applied with success to urinary alditol assay and to molecular weight determination by end group analysis. PMID:6846817

  5. Recovery of nitric acid from simulated acidic high level radioactive waste using pore-filled anion exchange membranes

    International Nuclear Information System (INIS)

    Acidic waste is generated at different stages of nuclear fuel cycle. The waste contains minor amounts of actinides (241Am, Pu, Np) along with large number of long-lived radionuclides such as 137Cs, 90Sr, 106Ru etc. Before disposal or storage, the overall activity of the waste needs to be reduced. Along with this, the high amount of acid present in the waste needs to be removed. In this study, DD has been used to recover nitric acid from acidic solutions with compositions similar to radioactive waste using pore-filled anion exchange membranes

  6. Evidence for F-/SiO- anion exchange in the framework of As-synthesized all-silica zeolites

    KAUST Repository

    Liu, Xiaolong

    2011-05-12

    Not everything changes: Charge-compensating anions can be exchanged in as-synthesized zeolite frameworks with changes in both the density of defect sites and of the hydrophobic character of the zeolite. The reversible transformation occurs without dissolution/recrystallization of the zeolite and preserves the size and shape of the crystals (see picture). Fluoride removal is not possible in all-silica D4R units, for which fluoride ions play a structure-directing role. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Dynamic separation of Szilard-Chalmers reaction products applied to the trioxalatochromium ion adsorbed on anionic exchange resin

    International Nuclear Information System (INIS)

    A method of dynamic elution of recoiled 51Cr+3, formed by the Szilard-Chalmers reaction during the irradiation of trioxalatochromium ion adsorbed on anionic exchange resin is presented. The influence of some factors on the separation yield of chromium-51, such as: composition, concentration and flow rate of eluent, mesh size of the resin and irradiation time are studied. The results are compardd with those obtained by the static method, in which the recoiled atom is separated from the target after irradiation. Because of the high separation yield of chromium-51, the method of dynamic separation is proposed for routine production of this elemnt, with high specific activities. (author)

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

    Directory of Open Access Journals (Sweden)

    P.U. Singare

    2014-06-01

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

  9. Preparation and testing of poly(4-vinylpyridine-DVB) based anion exchangers with enhanced selectivity for 99TcO4- ions present in radioactive effluents

    International Nuclear Information System (INIS)

    Three strong-base anion exchange resins were prepared by quaternization of poly(4-vinylpyridine-DVB) with different alkyl (-CH3, -C2H5, and -n-C4H9) halides. The base polymer in granular form was also synthesized in the laboratory. All three anion exchangers, base polymer and a conventional strong-base anion exchanger were characterized for moisture content, ion exchange capacity and batch uptake of 99TcO4- ions from acidic, neutral, and alkaline test solutions, each containing 1.0 M competing NO3- ions and 99mTcO4- radiotracer. Amongst the synthesized resins, the resin with bulky n-butyl group on the pyridine nitrogen showed higher affinity for 99TcO4- ions. (author)

  10. Highly efficient platinum group metal free based membrane-electrode assembly for anion exchange membrane water electrolysis.

    Science.gov (United States)

    Pavel, Claudiu C; Cecconi, Franco; Emiliani, Chiara; Santiccioli, Serena; Scaffidi, Adriana; Catanorchi, Stefano; Comotti, Massimiliano

    2014-01-27

    Low-temperature electricity-driven water splitting is an established technology for hydrogen production. However, the two main types, namely proton exchange membrane (PEM) and liquid alkaline electrolysis, have limitations. For instance, PEM electrolysis requires a high amount of costly platinum-group-metal (PGM) catalysts, and liquid alkaline electrolysis is not well suited for intermittent operation. Herein we report a highly efficient alkaline polymer electrolysis design, which uses a membrane-electrode assembly (MEA) based on low-cost transition-metal catalysts and an anion exchange membrane (AEM). This system exhibited similar performance to the one achievable with PGM catalysts. Moreover, it is very suitable for intermittent power operation, durable, and able to efficiently operate at differential pressure up to 3 MPa. This system combines the benefits of PEM and liquid alkaline technologies allowing the scalable production of low-cost hydrogen from renewable sources. PMID:24339230

  11. Enantioseparation of Dencichine and D-Isomer on L-Cysteine Derivative Phase by Ligand-exchange Chromatography

    Institute of Scientific and Technical Information of China (English)

    Yan Shun MA; Qing Hua MENG; Hong Yu SHI; Yuan De LONG; Tian Bao HUANG

    2006-01-01

    The enantioseparation of dencichine and its D-isomer was achieved on a novel chiral stationary phase via coating N-(2-hydroxyl-3-octoxyl) propyl-S-benzyl-(L)-cysteine on YWG-C18phase by ligand exchange chromatography.

  12. Illustrating Chromatography with Colorful Proteins

    Science.gov (United States)

    Lefebvre, Brian G.; Farrell, Stephanie; Dominiak, Richard S.

    2007-01-01

    Advances in biology are prompting new discoveries in the biotechnology, pharmaceutical, medical technology, and chemical industries. This paper presents a detailed description of an anion exchange chromatography experiment using a pair of colorful proteins and summarizes the effect of operating parameters on protein separation. This experiment…

  13. The influence of plutonium concentration and solution flow rate on the effective capacity of macroporous anion exchange resin

    International Nuclear Information System (INIS)

    The principal aqueous process used to recover and purify plutonium at the Los Alamos Plutonium Facility is anion exchange in nitric acid. Previous studies with gel-type anion exchange resin have shown an inverse relationship between plutonium concentration in the feed solution and the optimum flow rate for this process. Because gel-type resin has been replaced with macroporous resin at Los Alamos, the relationship between plutonium concentration and solution flow rate was reexamined with the selected Lewatit MP-500-FK resin using solutions of plutonium in nitric acid and in nitric acid with high levels of added nitrate salts. Our results with this resin differ significantly from previous data obtained with gel-type resin. Flow-rate variation from 10 to 80 liters per hour had essentially no effect on the measured quantities of plutonium sorbed by the macroporous resin. However, the effect of plutonium concentration in the feed solutions was pronounced, as feed solutions that contained the highest concentrations of plutonium also produced the highest resin loadings. The most notable effect of high concentrations of dissolved nitrate salts in these solutions was an increased resin capacity for plutonium at low flow rates. 16 refs., 7 figs., 2 tabs

  14. Determination of plutonium isotopes in urine samples from radiation workers using 236Pu tracer, anion exchange resin and alpha spectrometry

    International Nuclear Information System (INIS)

    Bioassay technique is used for the estimation of actinides present in the body based on their excretion rate through body fluids. For occupational radiation workers urine assay is the preferred method for monitoring of chronic internal exposure. Determination of low concentrations of actinides such as plutonium, americium and uranium at low level of mBq in urine by alpha spectrometry requires pre-concentration of large volumes of urine. This paper deals with standardization of analytical method for the determination of Pu-isotopes in urine samples using anion exchange resin and 236Pu tracer for radiochemical recovery. The method involves oxidation of urine followed by co-precipitation of plutonium along with calcium phosphate. Separation of Pu was carried out by Amberlite, IRA-400, anion exchange resin. Pu-fraction was electrodeposited and activity estimated using tracer recovery by alpha spectrometer. Twenty routine urine samples of radiation workers were analyzed and consistent radiochemical tracer recovery was obtained in the range 74-96% with a mean and standard deviation of 85 and 6% respectively. (author)

  15. Determination of thorium and uranium in activated concrete by inductively coupled plasma mass spectrometry after anion-exchange separation

    International Nuclear Information System (INIS)

    A sensitive analytical method was established for the determination of Th and U in activated concrete samples. The method combines an anion-exchange separation step with an ICP-MS determination technique. In the ICP-MS measurement, a few μg mL-1 of Al and Ca, a few ng mL-1 of Mn, La, Ce, Nd and Pb and pg mL-1amounts of Li, Zr, Nb and Ba coexisting in the anion-exchange fraction of Th and U did not interfere. No adverse interference effects were observed in real sample analyses. The obtained detection limits (3 σ, n = 10) of Th and U were 2.3 and 1.8 pg mL -1, respectively. The analytical precisions for ca. 5 μg g -1 Th and ca. 1 μg g -1 U in real activated concrete samples were equally less than 7% RSD. The accuracies obtained by the analysis of GSJ rock standard samples were -18.1 to 0.4% for the Th determination and -14.0 to -5.7% for the U determination. The method uses the conventional absolute calibration curve. The internal standard calibration is unnecessary. (orig.)

  16. Production of {sup 61}Cu using natural cobalt target and its separation using ascorbic acid and common anion exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujata Saha; Chattopadhyay, Sankha; Barua, Luna [Radiopharmaceuticals Laboratory, Board of Radiation and Isotope Technology (BRIT), Variable Energy Cyclotron Centre (VECC), Kolkata 700064 (India); Das, Malay Kanti, E-mail: mkdas@vecc.gov.in [Radiopharmaceuticals Laboratory, Board of Radiation and Isotope Technology (BRIT), Variable Energy Cyclotron Centre (VECC), Kolkata 700064 (India)

    2012-02-15

    {sup 61}Cu was produced by {sup nat}Co({alpha}, xn){sup 61}Cu reaction. {sup 61}Cu production yield was 89.5 MBq/{mu}Ah (2.42 mCi/{mu}Ah) at the end of irradiation (EOI). A simple radiochemical separation method using anion exchange resin and ascorbic acid has been employed to separate the product radionuclide from inactive target material and co-produced non-isotopic impurities. The radiochemical separation yield was about 90%. Radiochemical purity of {sup 61}Cu was >99% 1 h after EOI. Final product was suitable for making complex with N{sub 2}S{sub 2} type of ligands. - Highlights: Black-Right-Pointing-Pointer High purity, no-carrier added {sup 61}Cu produced from natural cobalt target. Black-Right-Pointing-Pointer {sup 61}Cu separated from impurities using anion exchange resin and ascorbic acid. Black-Right-Pointing-Pointer {sup 61}Cu preparation was successfully used to label N{sub 2}S{sub 2}-type of ligand.

  17. Recovery of uranium from UCF liquid waste by anion exchange resin CG-400: Breakthrough curves, elution behavior and modeling studies

    International Nuclear Information System (INIS)

    Highlights: ► Amberlite CG-400 anion exchange resin has been used for the recovery of uranium. ► The breakthrough curves and elution behaviors of CG-400 resin have been studied in detailed. ► The mathematical models have been used to analyze the experimental data. ► The CG-400 resin has been applied successfully for uranium recovery from UCF liquid waste. - Abstract: Continuous fixed-bed column studies were carried out by using Amberlite CG-400 anion exchange resin for the recovery of uranium from aqueous solutions (synthetic solutions and uranium conversion facility (UCF) liquid waste). Effects of operating parameters such as flow rate and bed height were studied. The breakthrough capacity decreases with increasing flow rate, but this dependence was not significant with a long column. The maximum breakthrough capacity of uranium ions were achieved by CG-400 resin at a flow rate of 0.2 mL min−1 and bed height 9.1 cm (4 g resin). The elution behavior of uranium from CG-400 resin by various eluents have been investigated and the results show that 0.5 mol L−1 HNO3 is a good eluent for uranium recovery. The Adams–Bohart, Thomas, Yoon–Nelson and Dose–Response models were applied to the experimental data to determine the characteristic parameters of the column for process design using linear regression. The breakthrough curve calculated from the Dose–Response model was in best agreement with the experimental data

  18. Synthesis and characterization of a novel hybrid material as amphoteric ion exchanger for simultaneous removal of cations and anions

    Energy Technology Data Exchange (ETDEWEB)

    Shah, Brijesh, E-mail: brijeshshah27@gmail.com; Chudasama, Uma, E-mail: uvcres@gmail.com

    2014-07-15

    Highlights: • A novel hybrid exchanger ZrD (zirconium diethylene triamine) is synthesized for the first time. • Characterization and structure elucidation reveals that ZrD exhibits amphoteric character. • Amphoteric behaviour of ZrD is established by simultaneous removal of cations and anions. • Cations are exchanged in ZrD through chelation with nitrogen as coordinating sites. • ZrD can be regenerated and reused with not much decline in performance. - Abstract: A new hybrid chelating ion exchanger zirconium diethylene triamine (ZrD) has been synthesized by a simple sol–gel route using inexpensive and easily available chemicals. ZrD has been characterized for elemental analysis (ICP-AES, CHN analysis), TGA, FTIR, X-ray diffraction, SEM and EDX. Physical and ion exchange characteristics as well as chemical stability of the material in various media have been studied. Structural determination reveals that ZrD exhibits amphoteric character. Anion exchange capacity (AEC) for Cl{sup −}, Br{sup −}, Cr{sub 2}O{sub 7}{sup 2−}, F{sup −} and AsO{sub 4}{sup 3−} has been determined. Cations are exchanged through chelation where coordinating sites are offered by nitrogen atoms present in the amine groups of ZrD. Distribution coefficient K{sub d} for Co{sup 2+}, Ni{sup 2+}, Cu{sup 2+}, Zn{sup 2+} (transition metal ions) and Hg{sup 2+}, Cd{sup 2+}, Pb{sup 2+} (heavy metal ions) has been evaluated by batch equilibration techniques in aqueous and various electrolyte media/concentrations. Based on α the separation factor, a few binary separations have been performed on a chromatographic column packed with ZrD. The amphoteric behaviour of ZrD has been demonstrated by simultaneous exchange of Cu{sup 2+} and Cl{sup −} in CuCl{sub 2}. A study on the regeneration and reuse of ZrD indicates that it is effective upto four cycles without much decline in performance.

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

    Institute of Scientific and Technical Information of China (English)

    卢建刚

    2004-01-01

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

  20. The degradation of strong basic anion exchange resins and mixed-bed ion-exchange resins: Effect of degradation products on radionuclide speciation

    International Nuclear Information System (INIS)

    The most important water-soluble products of the radiolytic degradation of anion exchange resins in a cementitious environment are ammonia and methylamines. These ligands do not form complexes with most radionuclides. Exceptions are Ni, Ag, and Pd, which form strong complexes with amines. Other degradation products of anion and mixed-bed ion-exchange resins are of no importance concerning the complexation of trivalent radionuclides. This is shown indirectly by adsorption experiments: The degradation products do not have a significant effect on the adsorption of Eu(III) on calcite. The effect of ammonia and methylamines on the complexation of Ni, Ag, and Pd is investigated by chemical modeling. For Ni and Ag, rather reliable predictions can be made using available thermodynamic data. In the case of Pd, large uncertainties are encountered due to unreliable data and gaps in the set of important species. The system Pd(II)-ammonia-water is explored in detail. Predominant species are inferred by chemical analogy, and their thermodynamic data are estimated. The uncertainty in these estimated and measured but unreliable data is bound by qualitative and quantitative chemical reasoning

  1. Studies of removal of palladium(II) ions from chloride solutions on weakly and strongly basic anion exchangers.

    Science.gov (United States)

    Hubicki, Z; Wołowicz, A; Leszczyńska, M

    2008-11-30

    Palladium and its compounds find wide application in industry as a catalytic agent in different manufacture processes. Recovery of precious metals from industrial wastes is difficult and time consuming but in spite of these disadvantages it becomes profitable. Palladium(II) ions sorption from various chloride solutions of the composition: 0.1-6.0M HCl-0.00056 M Pd(II), 1.0M ZnCl(2)-0.1M HCl-0.00056 M Pd(II), 1.0M AlCl(3)-0.1M HCl-0.00056 M Pd(II) on the weakly and strongly basic anion exchangers (Varion ATM, Varion ADM and Varion ADAM) was discussed. The sorption research of Pd(II) ions on these resins was carried out by means of static and dynamic methods. The dynamic processes were applied in order to determine the breakthrough curves of Pd(II) ions. Moreover, the working ion-exchange capacities as well as the weight and bed distribution coefficients were determined from the Pd(II) breakthrough curves. The recovery factors of Pd(II) ions (% R) depending on the phase contact time were obtained by means of static methods. The highest ion-exchange capacities for the 0.1-6.0M HCl-0.00056 M Pd(II) systems were obtained for the weakly basic ion-exchange resin Varion ADAM. PMID:18358602

  2. Properties of solvated electrons, alkali anions and other species in metal solutions and kinetics of cation and electron exchange reactions. Final report

    International Nuclear Information System (INIS)

    The properties of solutions of alkali metals in amine solvents were studied by optical, ETR, NMR and electrochemical methods. Complexation of the alkali cations by crown ethers and cryptands permitted the preparation of concentrated solutions of alkali metals in amine and ether solvents. Extensive alkali metal NMR studies of the exchange of M+ with crown-ethers and cryptands and of the alkali metal anion, M-, were made. The first crystalline salt of an alkali metal anion, Na+ Cryptand [2.2.2]Na- was synthesized and characterized and led to the preparation of other alkali metal anion salts. This research provided the foundation for continuing studies of crystalline alkalide salts

  3. Stable and selective scintillating anion-exchange sensors for quantification of 99TcO4− in natural freshwaters

    International Nuclear Information System (INIS)

    New dual functionality scintillating anion-exchange resins were developed for selective determination of 99TcO4− in various natural freshwater samples. Stable scintillating particles were formed by preparing the vinyl monomer 2-[4-(4′-vinylbiphenylyl)]-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (vPBD), starting with the commercial organic flour TBut-PBD and its subsequent copolymerization with styrene, divinylbenzene, and p-chloromethylstyrene mixture. To integrate the radiochemical separation and radiometric detection steps within the same bead, the chloromethyl groups of the scintillating resins were subjected to amination reactions with dioctylamine (DOA) and trioctylamine (TOA). On-line quantification of 99TcO4− was achieved by packing the scintillating anion-exchange resin into Teflon tubing for quantification by a flow scintillation analyzer (FSA). The two functionalized resins were selective for pertechnetate over the common anions in natural freshwaters, especially Cl− and SO42− with up to 1000 ppm and with up to 10 ppm I− and Cr2O72−. The uptake efficiency of the TOA sensor decreased from 97.88% to 85.08% in well water and river water, respectively, while the counting efficiency was almost constant (69.50%). The DOA performance showed lower efficiency in the two water types relative to TOA. On the other hand, the DOA sensor could be regenerated by 5 M HNO3 for reuse at least four times without losing its chemical or optical performance. The detection limit was 1.45 Bq which could be achieved by loading 45 mL from well and tap water containing the maximum contaminant level (MCL) of 99Tc (33 Bq/L). -- Highlights: • Two novel extractive scintillating sensors for monitoring 99TcO4− were developed. • The resins are selective for pertechnetate over the common anions and chromate ions. • The materials have high chemical and optical stability with good detection efficiency. • 99TcO4− was determined in three freshwaters contain different

  4. Heterometallic modular metal-organic 3D frameworks assembled via new tris-β-diketonate metalloligands: nanoporous materials for anion exchange and scaffolding of selected anionic guests.

    Science.gov (United States)

    Carlucci, Lucia; Ciani, Gianfranco; Maggini, Simona; Proserpio, Davide M; Visconti, Marco

    2010-11-01

    -48% of the cell volume and include the anions and many guest solvent molecules. The guest solvent molecules can be reversibly removed by thermal activation with retention of the framework structure, which proved to be stable up to about 270°C, as confirmed by TGA and powder XRD monitoring. The anions could be easily exchanged in single-crystal to single-crystal processes, thereby allowing the insertion of selected anions into the framework channels. PMID:20938934

  5. Molecular physiology and genetics of Na+-independent SLC4 anion exchangers

    OpenAIRE

    Alper, Seth L.

    2009-01-01

    Plasmalemmal Cl–/HCO3– exchangers are encoded by the SLC4 and SLC26 gene superfamilies, and function to regulate intracellular pH, [Cl–] and cell volume. The Cl–/HCO3– exchangers of polarized epithelial cells also contribute to transepithelial secretion and reabsorption of acid–base equivalents and Cl–. This review focuses on Na+-independent electroneutral Cl–/HCO3– exchangers of the SLC4 family. Human SLC4A1/AE1 mutations cause the familial erythroid disor...

  6. Do TFSA Anions Slither? Pressure Exposes the Role of TFSA Conformational Exchange in Self-Diffusion.

    Science.gov (United States)

    Suarez, Sophia N; Rúa, Armando; Cuffari, David; Pilar, Kartik; Hatcher, Jasmine L; Ramati, Sharon; Wishart, James F

    2015-11-19

    Multinuclear ((1)H, (2)H, and (19)F) magnetic resonance spectroscopy techniques as functions of temperature and pressure were applied to the study of selectively deuterated 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (EMIM TFSA) ionic liquid isotopologues and related ionic liquids. For EMIM TFSA, temperature-dependent (2)H T1 data indicate stronger electric field gradients in the alkyl chain region compared to the imidazolium ring. Most significantly, the pressure dependences of the EMIM and TFSA self-diffusion coefficients revealed that the displacements of the cations and anions are independent, with diffusion of the TFSA anions being slowed much more by increasing pressure than for the EMIM cations, as shown by their respective activation volumes (28.8 ± 2.5 cm(3)/mol for TFSA vs 14.6 ± 1.3 cm(3)/mol for EMIM). Increasing pressure may lower the mobility of the TFSA anion by hindering its interconversion between trans and cis conformers, a process that is coupled to diffusion according to published molecular dynamics simulations. Measured activation volumes (ΔV(‡)) for ion self-diffusion in EMIM bis(fluoromethylsulfonyl)amide and EMIM tetrafluoroborate support this hypothesis. In addition, (2)H T1 data suggest increased ordering with increasing pressure, with two T1 regimes observed for the MD3 and D2 isotopologues between 0.1-100 and 100-250 MPa, respectively. The activation volumes for T1 were 21 and 25 cm(3)/mol (0-100 MPa) and 11 and 12 cm(3)/mol (100-250 MPa) for the MD3 and D2 isotopologues, respectively. PMID:26509865

  7. Measuring various anions content in water with ion chromatography method%离子色谱法测定水中多种阴离子的含量

    Institute of Scientific and Technical Information of China (English)

    徐胜

    2014-01-01

    介绍了离子色谱仪的工作原理与工作流程,对离子色谱法测定水中多种阴离子含量的试验方法进行了论述,通过试验得到了水中各离子的标准物质色谱图、标准曲线及标准溶液度的偏差等,指出运用离子色谱法测定水中阴离子含量操作方便,效率高。%The paper introduces the working principles and working procedures of ion chromatography, discusses various anions content testing method with ion chromatography method, and achieves their standard chromatogram, standard curve and standard solution errors and so on, and finally points out advantages of applying ion chromatography method to test anions content, such as convenient operation and high efficiency.

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

    Science.gov (United States)

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

    2015-04-01

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

  9. The Role of Anion Exchanger on Pulmonary Vascular Response to Sustained Alveolar Hypoxia in the Isolated Perfused Rabbit Lung

    Directory of Open Access Journals (Sweden)

    Farzaneh Ketabchi

    2015-05-01

    Full Text Available Background: Some respiratory diseases may induce alveolar hypoxia thereby hypoxic pulmonary vasoconstriction (HPV. However, the mechanisms of this physiologic phenomenon are not fully understood. This study was the first to investigate the role of anion exchanger in sustained HPV. Methods: Experiments were performed in the isolated perfused rabbit lung. After preparation, the lungs were divided into six groups: two DIDS (4,4-diisothiocyanostilbene 2,2-disulfonic acid, anion exchanger inhibitor-treated [200 µM (n=5 or 400 µM (n=3] hypoxic groups, two HCO3- free hypoxic groups, one control hypoxic group (n=7 and one control normoxic group (n=4. DIDS were added to the perfusate at 10 minutes before starting the experiments. In the HCO3- free groups, HEPES (4-(2-Hydroxyethylpiperazine-1-ethanesulfonic acid were added to the perfusate instead of bicarbonate. Furthermore, in the HEPES1 (n=4 and HEPES2 (n=4 groups, the lungs were ventilated with hypoxic gas with or without CO2, respectively. Results: Ventilation of the lungs with hypoxic gas resulted in biphasic HPV, the acute (0-20 minutes and sustained (20-60 minutes phases. No alteration in both phases of HPV was detected by DIDS (200 µM. However, DIDS (400 µM, extended the ascending part of acute HPV until min 24. Both phases of HPV were decreased in the HEPES1 group. However, in the HEPES 2 group, HPV tended to increase during the rising part of the acute phase of HPV. Conclusions: Since DIDS (400 µM extended acute phase of HPV, and HCO3- free perfusate buffer enhanced rising phase of it, therefore it can be suggested that anion exchanger may modulate HPV especially during the acute phase. The abstract of this article was presented as a poster in the congress of European Respiratory Society (ERS on Monday, 08 September 2014, Munich, Germany and was published in the ERJ September 1, 2014 vol. 44 no. Suppl 58 P2343.

  10. Refolding of Denatured/Reduced Lysozyme Using Weak-Cation Exchange Chromatography

    Institute of Scientific and Technical Information of China (English)

    Yan WANG; Bo Lin GONG; Xin Du GENG

    2003-01-01

    Oxidative refolding of the denatured/reduced lysozyme was investigated by using weak-cation exchange chromatography (WCX). The stationary phase of WCX binds to the reduced lysozyme and prevented it from forming intermolecular aggregates. At the same time urea and ammonium sulfate were added to the mobile phase to increase the elution strength for lysozyme. Ammonium sulfate can more stabilize the native protein than a common eluting agent, sodium chloride. Refolding of lysozyme by using this WCX is successfully. It was simply carried out to obtain a completely and correctly refolding of the denatured lysozyme at high concentration of 20.0 mg/mL.

  11. Determination of {sup 129}I in environmental samples by AMS and NAA using an anion exchange resin disk

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Takashi [AMS Management Section, Mutsu Establishment, Japan Atomic Energy Agency, 4-24, Minato-machi, Mutsu, Aomori 035-0064 (Japan)]. E-mail: suzuki.takashi58@jaea.go.jp; Banba, Shigeru [Natural Radioactivity Analysis Group, Japan Chemical Analysis Center, 295-3, Sanno-cho, Inage-ku, Chiba-shi, Chiba 263-0002 (Japan); Kitamura, Toshikatsu [AMS Management Section, Mutsu Establishment, Japan Atomic Energy Agency, 4-24, Minato-machi, Mutsu, Aomori 035-0064 (Japan); Kabuto, Shoji [AMS Management Section, Mutsu Establishment, Japan Atomic Energy Agency, 4-24, Minato-machi, Mutsu, Aomori 035-0064 (Japan); Isogai, Keisuke [Natural Radioactivity Analysis Group, Japan Chemical Analysis Center, 295-3, Sanno-cho, Inage-ku, Chiba-shi, Chiba 263-0002 (Japan); Amano, Hikaru [AMS Management Section, Mutsu Establishment, Japan Atomic Energy Agency, 4-24, Minato-machi, Mutsu, Aomori 035-0064 (Japan)

    2007-06-15

    We have developed a new extraction method for the measurement of {sup 129}I by accelerator mass spectrometry (AMS) utilizing an anion exchange resin disk. In comparison to traditional methods such as solvent extraction and ion exchange, this method provides for simple and quick sample handling. This extraction method was tested on soil, seaweed and milk samples, but because of disk clogging, the milk samples and some of the seaweed could not be applied successfully. Using this new extraction method to prepare samples for AMS analysis produced isotope ratios of iodine in good agreement with neutron activation analysis (NAA). The disk extraction method which take half an hour is faster than previous techniques, such as solvent extraction or ion exchange which take a few hours. The combination of the disk method and the AMS measurement is a powerful tool for the determination of {sup 129}I. Furthermore, these data will be available for the environmental monitoring before and during the operation of a new nuclear fuel reprocessing plant in Japan.

  12. Determination of 129I in environmental samples by AMS and NAA using an anion exchange resin disk

    International Nuclear Information System (INIS)

    We have developed a new extraction method for the measurement of 129I by accelerator mass spectrometry (AMS) utilizing an anion exchange resin disk. In comparison to traditional methods such as solvent extraction and ion exchange, this method provides for simple and quick sample handling. This extraction method was tested on soil, seaweed and milk samples, but because of disk clogging, the milk samples and some of the seaweed could not be applied successfully. Using this new extraction method to prepare samples for AMS analysis produced isotope ratios of iodine in good agreement with neutron activation analysis (NAA). The disk extraction method which take half an hour is faster than previous techniques, such as solvent extraction or ion exchange which take a few hours. The combination of the disk method and the AMS measurement is a powerful tool for the determination of 129I. Furthermore, these data will be available for the environmental monitoring before and during the operation of a new nuclear fuel reprocessing plant in Japan

  13. Liquid–liquid anion exchange extraction studies of samarium(III from salicylate media using high molecular weight amine

    Directory of Open Access Journals (Sweden)

    Aniruddha M. Mandhare

    2015-07-01

    Full Text Available Liquid–liquid extraction and separation of samarium(III were carried out by using 0.025 mol dm−3 2-octylaminopyridine(2-OAP in xylene at 298 K. The extraction behavior of samarium was studied as a function of pH, weak acid concentration, extractant concentration, diluent, and equilibration time. Samarium was quantitatively extracted at pH 7.5 to 10.0 from 0.01 mol dm−3 sodium salicylate solution with 0.025 mol dm−3 2-OAP. The possible composition of the extracted species in organic phase has been determined by using model of slope analysis method and extraction mechanism was found to proceed via an anion exchange mechanism. The stripping efficiency was found to be quantitative in HNO3, HCl and CH3COOH. The robustness of the procedure was demonstrated by the average recoveries obtained (>99.6% for samarium(III extraction in the presence of several cations and anions which are commonly associated with it. The proposed method facilitates the separation and determination of samarium(III from binary and synthetic mixtures. The various thermodynamic functions like free energy (ΔG, enthalpy (ΔH and entropy (ΔS of extraction mechanism were discussed.

  14. A SIM-MOF: three-dimensional organisation of single-ion magnets with anion-exchange capabilities.

    Science.gov (United States)

    Baldoví, José J; Coronado, Eugenio; Gaita-Ariño, Alejandro; Gamer, Christoph; Giménez-Marqués, Mónica; Mínguez Espallargas, Guillermo

    2014-08-18

    The formation of a metal-organic framework (MOF) with nodes that have single-molecule magnet (SMM) behaviour has been achieved by using mononuclear lanthanoid analogues, also known as single-ion magnets (SIMs), which enormously simplifies the challenging issue of making SMM-MOFs. Here we present a rational design of a family of MOFs, [Ln(bipyNO)4](TfO)3⋅x solvent (Ln=Tb (1); Dy (2); Ho (3); Er (4); TfO=triflate), in which the lanthanoid centres have an square-antiprismatic coordination environment suitable for SIM behaviour. Magnetic measurements confirm the existence of slow magnetic relaxation typical of SMMs, which has been rationalised by means of a radial effective charge model. In addition, we have explored the incorporation of bulky polyoxometalates (POMs) into the cavities of the SIM-MOF by anion exchange, finding that they do not interfere with the slow magnetic relaxation. This demonstrates the robustness of the frameworks and opens the possibility of incorporating non-innocent anions. PMID:24804629

  15. Studies on the recovery of plutonium from hydrochloric acid-oxalic acid solutions using anion exchange method

    International Nuclear Information System (INIS)

    The sorption of Pu(IV) from aqueous hydrochloric acid-oxalic acid medium was investigated using different anion exchangers viz., Dowex-1X4, Amberlyst A-26, and Amberlite XE-270 for developing a method for recovery of plutonium from oxalate waste. The distribution ratios for the sorption of Pu(IV) determined as a function of [HClx59', [oxalic acidx59' and [AlCl3x59' revealed that the sorption of Pu(IV) from ≤ 4 M HCl is too low for recovery. The distribution ratio for Pu(IV) increases significantly as the concentration of HCl> 6M. Sorption of Pu(IV) by all the resins decreases drastically in presence of oxalic acid. However, the sorption of Pu(IV) from hydrochloric acid-oxalic acid solutions increases substantially in presence of AlCl3 making the recovery feasible. (author). 2 refs., 2 tabs

  16. Determination of gold in low grade ores and concentratrs by anion exchange separation followed by neutron activation

    International Nuclear Information System (INIS)

    The benefication of tailings fror Kolar Gold Mines involves the flotation of sulphides. Appreciable amounts of arsenic and antimony are expected to accompany gold in this process. The activation analysis of gold in these samples is facilitated by a preseparation of gold from arsenic and antimony. The present paper describes a method for the rapid analysis of gold in the concentration range 0.5 to 50 ppm using a simple pre-irradiation separation, with the recovery of gold being evaluated by an isotope dilution technique using 198Au tracer. The method is based on the absorption of the AuCl4- complex on anion-exchange resin in conjuction with isotope dilution technicque to evaluate the recovery of gold. The resin is then irradiated and counted along with a reference standard similarly prepared. (T.G.)

  17. Analytical applications of a liquid anion-exchanger for the separation of uranium(IV) in malonate solution.

    Science.gov (United States)

    Dalvi, M B; Khopkar, S M

    1978-10-01

    Uranium was quantitatively extracted with 4% Amberlite LA-1 in xylene at pH 2.5-4.0 from 0.001 M malonic acid. It was stripped from the organic phase with 0.01 M sodium hydroxide and determined spectrophotometrically at 530 nm as its complex with 4-(2-pyridylazo) resorcinol. Of various liquid anion-exchangers tested, Amberlite LA-1 was found to be best. Uranium was separated from alkali and alkaline earth metal ions, thallium(I), iron(II), silver, arsenic(III) and tin(IV) by selective extraction, and from zinc, cadmium, nickel, copper(II), cobalt(II), chromium(III), aluminium, iron(III), lead, bismuth, antimony(III) and yttrium by selective stripping. The separation from scandium, zirconium, thorium and vanadium(V) was done by exploiting differences in the stability of chloro-complexes. PMID:18962334

  18. Examination of Amine-Functionalised Anion-Exchange Membranes for Possible Use in the All-Vanadium Redox Flow Battery

    International Nuclear Information System (INIS)

    The applicability of amine-functionalised anion-exchange membranes (AEMs) for use in the all-vanadium redox flow battery has been studied. A selection of radiation-grafted aminated membranes functionalised with dimethylamine, trimethylamine or diazabicyclo(2,2,2)octane were extensively tested. The success of each grafting process was confirmed by Raman and infrared spectroscopies, titrimetry and ionic conductivity measurements. The amine-functionalised membranes were found to have poor thermo-oxidative stability and high vanadium cation permeabilities. The results highlight the importance of balancing ionic conductivity with vanadium cation permeability and indicate that amine-based functional groups may not be suitably stable for the membranes to remain true AEMs when in use in the all-vanadium redox flow battery

  19. Imidazolium-Functionalized Anion Exchange Polymer Electrolytes with High Tensile Strength and Stability for Alkaline Membrane Fuel Cells

    International Nuclear Information System (INIS)

    This study reports novel kinds of high tensile strength alkaline anion-exchange membranes composed of imidazolium-functionalized anion exchange polymer electrolytes. The membranes were prepared by a combined thermal and chemical cross-linking of poly (vinyl alcohol) and poly (3-methyl-1-vinylimidazolium chloride)-co-(1-vinylpyrrolidone) (PMVIC-co-VP). Characterizations by AC impedance technique, mechanical property, FTIR spectroscopy, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), along with the water uptake, alkaline resistance and oxidation stability were carried out on the membranes consisting of different PVA/PVA-PMVIC-co-VP mass ratios to evaluate their applicability in alkaline fuel cells. The membrane in a mass ratio of 1:0.4 exhibited high tensile stress at break in the range of 59.3∼76.6 MPa, and the elongation at break around 9.2∼14.9%, depending on the annealing temperature from 130∼190 °C. The OH− conductivity of the membranes was found to be increased with increasing annealing temperature and mass ratio, and reached high up to 1.7 × 10−2 S cm−1. Besides, the membranes showed perfect oxidation stability in 30% H2O2 for 250 hours with no obvious weight loss was observed. XPS analysis indicated that some degradation occurred when the membrane was exposed to 8 M KOH at 85 °C for 312 h, but no lessened OH− conductivity was detected. SEM pictures revealed an ordered microvoid structure with pore size ca. 100∼150 nm uniformly dispersed on the membrane surface, which imparted the PVA/PVA-PMVIC-co-VP membrane with good OH− conductivity

  20. Design of expanded bed supports for the recovery of plasmid DNA by anion exchange adsorption

    DEFF Research Database (Denmark)

    Theodossiou, Irini; Søndergaard, M.; Thomas, Owen R. T.

    In this study we detail the rational design of new chromatographic adsorbents tailored for the capture of plasmid DNA. Features present on current chromatographic supports that can significantly enhance plasmid binding capacity have been identified in packed bed chromatography experiments and...... sensitivity to inter-particle bridging by nucleic acid polymers, gave low DNA recoveries (<37%) and proved difficult to regenerate. In contrast, few operational difficulties were experienced with the diethylaminoethyl-linked prototype adsorbent and successful high capacity (>0.8 mg ml(-1)) capture of plasmid...... DNA from crude neutralised E. coli lysate was demonstrated....

  1. Sequential determination system for anionic detergents by complexation with methylene blue by dual high-speed counter-current chromatography

    OpenAIRE

    Kitazume, Eiich; Koikawa, Saki; Hui, Lu; Sannohe, Syou; Yang, Yanjun; Yonosuke, Maki; Ito, Yoichiro

    2012-01-01

    A new dual high-speed counter-current chromatographic system using organic extraction phase and aqueous mobile phase containing methylene blue was applied to the analysis of anionic-type detergents. After selecting appropriate conditions such as flow rate of each mobile phase, sample volume, etc., the new system was successfully applied to the analysis of anionic detergent in river water. As all the analytical procedure can be made in a closed system, the method has no health hazard. The pres...

  2. Evaluation of glycidyl methacrylate-based monolith functionalized with weak anion exchange moiety inside 0.5 mm i.d. column for liquid chromatographic separation of DNA

    Directory of Open Access Journals (Sweden)

    Aprilia Nur Tasfiyati

    2016-03-01

    Full Text Available In this study, the organic polymer monolith was developed as a weak anion exchanger column in high performance liquid chromatography for DNA separation. Methacrylate-based monolithic column was prepared in microbore silicosteel column (100 × 0.5 mm i.d. by in-situ polymerization reaction using glycidyl methacrylate as monomer; ethylene dimethacrylate as crosslinker; 1-propanol, 1,4-butanediol, and water as porogenic solvents, with the presence of initiator α,α′-azobisisobutyronitrile (AIBN. The monolith matrix was modified with diethylamine to create weak anion exchanger via ring opening reaction of epoxy groups. The morphology of the monolithic column was studied by SEM. The properties of the monolithic column, such as permeability, mechanical stability, binding capacity and pore size distribution, were characterized in detail. From the results of the characterization, monoliths poly-(GMA-co-EDMA with total monomer percentage (%T 40 and crosslinker percentage (%C 25 was found to be the ideal composition of monomer and crosslinker. It has good mechanical stability and high permeability, adequate molecular recognition sites (represented with binding capacity value of 36 mg ml−1, and has relatively equal proportion of flow-through pore and mesopores (37.2% and 41.1% respectively. Poly-(GMA-co-EDMA with %T 40 and %C 25 can successfully separate oligo(dT12–18 and 50 bp DNA ladder with good resolution.

  3. Separation of plutonium on the anion exchanger BIO-RAD 1-X2 and its application to radiochemical analysis

    International Nuclear Information System (INIS)

    The element Pu (Z = 94) is a member of the actinide series of the elements (Z = 89 -103). The actinides have similar chemical properties and are also similar to the lanthanides (Z = 57 -71). Sixteen isotopes of Pu have been synthesized, all of which are radioactive. The Pu present in the environment originates from the atmospheric nuclear tests from 1950 to 1963, which produced the so-called 'global fallout'. As a result, 6.5 · 1015 Bq 239Pu (2.8 tons), 4.4 · 1015 Bq 240Pu (0.52 tons), and 3.7 · 104 Bq 241Pu (0.04 tons) were dispersed over the world. A contribution also to the global fallout was the ignition of the satellite SWAP 9A in the atmosphere in 1964, equipped with a battery powered by 6.3 · 1014 Bq (1 kg) of 238Pu. In addition to these sources, nuclear reactors, reprocessing plants and radioactive waste facilities may contribute with their emissions to increase locally the Pu concentration in their environment. In the PSI laboratory, we are confronted with the determination of traces of 238Pu, 239Pu and 240Pu in environmental and biological materials. Because of the low quantity of Pu in the analyzed samples, which is usually below 100 mBq, it is mandatory to separate the Pu from all other accompanying elements. The separated Pu is then measured by alpha spectrometry. In this work, the anion exchanger BIO-RAD AG 1 is extensively used for the separation of Pu from different matrices. This exchanger is superior when only Pu is determined in the sample. In addition, it is also very suitable when other actinides, such as Am and Cm, are also determined. No preconcentration step is necessary for the Pu separation. The resins introduced by the company Eichrom Industries in the 90's, which allow the separation of the actinides from the major environmental elements and from each other, requires relatively small volumes of sample solution. This report describes the extensive utilization of the classical anion exchanger BIO-RAD 1-X2 in 8 molar nitric acid for the

  4. INTERACTION MECHANISM OF ORGANIC MATTER WITH GEL TYPE POLYSTYRENE STROUGLY BASIC ANION EXCHANGE RESIN AND REGENERATION OF THE ORGANISM FOULED RESIN I.The interreaction mechanism be

    Institute of Scientific and Technical Information of China (English)

    ZhuXingbao; WangZhansen; 等

    1995-01-01

    It was generally considered that contamination of the gel type polystyrene strong basic anion exchange resin by or ganic matter in natural water is the result of ion exchange and Van der waal′s adsorption on it.On the basis of laboratory and industrial experiments,this paper confirmed that the interreaction between organic matter and resin polymer matrix is primarily controled by a Van der waal′s adsorption.

  5. P123-T Oligonucleotide Purification Strategies using a New High-Capacity Anion Exchange Resin

    OpenAIRE

    Deetz, M.; Fisher, J. R.; Gehris, A.; Maikner, J.; Kinzey, M.

    2007-01-01

    With the advent of nucleic acid silencing technologies and the need for high purity diagnostic and therapeutic oligonucleotides, there is a need for high-capacity chromatographic supports that can deliver economic purification processes. A new, 30 micron, mono-sized, polymeric resin has been recently developed that provides high resolution and high capacity for synthetic oligonucleotides. Physical properties of this new resin will be described, including particle size uniformity, ion exchange...

  6. Investigation on the Use of the Weakly Basic Polyacrylate Anion-Exchanger Amberlite IRA-68 for Sorption and Separation of Iminodiacetate Complexes of Rare Earth Elements

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on the determined affinity series of rare earth element complexes with IMDA for the anion-exchangers, purification of macroquantities of Nd3+ from Y3+, Sm3+ from Ho3+, La3+ from Nd3+ and La3+ from Pr3+ on the weakly basic gel anion-exchanger Amberlite IRA-68 was studied. Using the presented method on 1 L of Amberlite IRA-68 in the acetate form, it is possible to obtain about 240 g Nd2O3 purified from Y2O3. Great difference in affinity of La3+ and Nd3+ as well as Pr3+ complexes for this anion-exchanger in the acetate form indicates the possibility of applying this process for purification of lanthanum on the increased scale. On 1 L of Amberilte IRA-68 in the acetate form it is possible to obtain about 1125 g La2O3 purified from Nd2O3. On the basis of these results it can be assumed that unique properties of polyacrylate anion-exchangers enable their application for separation of rare earth elements.

  7. Complexation or uranyl ion. II. Complexation of uranyl ion in the VP-IAp anion exchanger phase during sorption from carbonate media

    International Nuclear Information System (INIS)

    The complicated process of increased uranium sorption from carbonate medium by the strongly basic anion exchanger VP-1Ap after additional treatment with alkaline solution was studied by IR spectroscopy. The process is related to the formation of certain complex forms of uranyl, differing in degree of polymerization, in which polynuclear forms predominate

  8. Comparison in the extraction properties of Pu(IV) in piperidinium and pyrrolidinium nitrate anchored anion exchange resins

    Energy Technology Data Exchange (ETDEWEB)

    Selvan, B. Robert; Suneesh, A.S.; Venkatesan, K.A.; Antony, M.P.; Vasudeva Rao, P.R. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Fuel Chemistry Div.

    2016-07-01

    Piperidinium nitrate (Pip-NO{sub 3}) and pyrrolidinium nitrate (Pyr-NO{sub 3}) functional groups were anchored on a poly(styrene-divinylbenzene) matrix and evaluated the resultant anion exchange resin for the extraction of plutonium from nitric acid medium. The distribution coefficient (K{sub d}, mL/g) of Pu(IV) in these resins increased with the concentration of nitric acid, reaching a maximum K{sub d} at 7 M nitric acid, followed by decrease. The extraction of Pu(IV) increased with the duration of equilibration followed by the establishment of equilibrium, occurred within four hours of equilibration. The kinetic data were fitted with pseudo-first order and pseudo-second order rate equations. The apparent plutonium exchange capacity was determined to be ∝256 mg/g for Pip-NO{sub 3} resin and 285 mg/g for Pyr-NO{sub 3} resin at 7 M nitric acid. The radiolytic degradation of Pip-NO{sub 3} and Pyr-NO{sub 3} in presence of nitric acid (7 M) was studied upto a dose of 200 KGy and the results are reported in this paper.

  9. Sub-Zero Temperature Chromatography for Reduced Back-Exchange and Improved Dynamic Range in Amide Hydrogen Deuterium Exchange Mass Spectrometry

    OpenAIRE

    Venable, John D.; Okach, Linda; Agarwalla, Sanjay; Brock, Ansgar

    2012-01-01

    Amide hydrogen/deuterium exchange is a commonly used technique for studying the dynamics of proteins and their interactions with other proteins or ligands. When coupled with liquid chromatography and mass spectrometry, hydrogen/deuterium exchange provides several unique advantages over other structural characterization techniques including very high sensitivity, the ability to analyze proteins in complex environments, and a large mass range. A fundamental limitation of the technique arises fr...

  10. Chromium (VI removal from aqueous solutions by purolite base anion-exchange resins with gel structure

    Directory of Open Access Journals (Sweden)

    Balan Catalin

    2013-01-01

    Full Text Available The removal of Cr (VI from aqueous solution using two strong base anionic resins with gel structure, Purolite A-400 (styrene-divinylbenzene matrix and Purolite A-850 (acrylic matrix was investigated in batch technique. The sorption efficiency was determined as a function of phases contact time, solution pH, resin dose, temperature and initial Cr (VI concentration. The percentage of Cr (VI removed reaches maximum values (up to 99 % in the pH range 4 - 5.3 under a resin dose of 6 g/L and of Cr (VI concentration up to 100 mg/L. An increase in temperature has a positive effect on the Cr (VI sorption process. The equilibrium sorption data were fitted with the Freundlich, Langmuir and Dubinin-Radushkevich isotherm models, using both linear and nonlinear regression method. The Langmuir model very well verifies the experimental data and gives the maximum sorption capacity of 120.55 mg Cr (VI/g and 95.82 mg Cr (VI/g for A-400 and A-850 resins, respectively. The thermodynamic study and mean free energy of sorption values calculated using Dubinin-Radushkevich equation indicated the sorption is a chemical endothermic process. The kinetic data were well described by pseudo-second order kinetic equation and the sorption process is controlled by external (film diffusion and intraparticle diffusion.

  11. Determination of plutonium in environmental samples by controlled valence in anion exchange

    DEFF Research Database (Denmark)

    Chen, Q.J.; Aarkrog, A.; Nielsen, S.P.;

    1993-01-01

    The title method was successfully used for collecting Pu-239, Pu-249 from 200 litres of seawater by coprecipitation with 16 g FeSO4 . 7H2O under reducing conditions without filtering. The plutonium is leached by concentrated HNO3 + HCI from the coprecipitate and the solid particles. The precipitate...... is heated at 400-degrees-C and digested in aqua regia. Na2SO3 and NaNO2 have been applied to obtain the Pu4+ valence state in 0.571 N HN03 for different samples. Plutonium and thorium are coadsorbed on anionic resin from 8N HN03. The column is eluted with 8N HN03 containing fresh NaNO2 to keep the Pu4......+ state for uranium decontamination. The system of the column is changed from 8N HNO3 to concentrated HCl with 50 ml concentrated HCI containing a few milligrams of NaNO2. Further decontamination of thorium was achieved by elution with concentrated HCI instead of 9N HCl. The plutonium is successfully...

  12. Characterization of an anionic-exchange membranes for direct methanol alkaline fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Abuin, Graciela C. [Centro de Procesos Superficiales, Instituto Nacional de Tecnologia Industrial (INTI), Av. Gral. Paz 5445, B1650KNA, San Martin, Buenos Aires (Argentina); Nonjola, Patrick; Mathe, Mkhulu K. [Council for Scientific and Industrial Research (CSIR), Material Science and Manufacturing, PO Box 395, Brumeria, Pretoria 0001 (South Africa); Franceschini, Esteban A.; Izraelevitch, Federico H.; Corti, Horacio R. [Departamento de Fisica de la Materia Condensada, Comision Nacional de Energia Atomica (CNEA), Av. Gral. Paz 1499, B1650KNA, San Martin, Buenos Aires (Argentina)

    2010-06-15

    Ammonium quaternized polymers such as poly (arylene ether sulfones) are being developed and studied as candidates of ionomeric materials for application in alkaline fuel cells, due to their low cost and promising electrochemical properties. In this work, a quaternary ammonium polymer was synthesized by chloromethylation of a commercial polysulfone followed by amination process. Quaternized polysulfone membrane properties such us water and water-methanol uptake, electrical conductivity and Young's modulus were evaluated and compared to Nafion 117, commonly employed in direct methanol fuel cells. The anionic polysulfone membrane sorbs more water than Nafion all over the whole range of water activities, but it uptakes much less methanol as compared to Nafion. The specific conductivity of the fully hydrated polysulfone membrane equilibrated with KOH solutions at ambient temperature increases with the KOH concentration, reaching a maximum of 0.083 S cm{sup -1} for 2 M KOH, slightly less conductive than Nafion 117. The elastic modulus of the polysulfone membranes inmersed in water is similar to that reported for Nafion membranes under the same conditions. We concluded that quaternized polysulfone membrane are good candidates as electrolytes in alkaline direct methanol fuel cells. (author)

  13. Determination of plutonium in environmental samples by controlled valence in anion exchange

    International Nuclear Information System (INIS)

    The method was successfully used for collecting 239,240Pu from 200 litres seawater by coprecipitation with 16 g FeSO4.7H2O under reducing conditions without filtering. The plutonium is leached by concentrated HNO3 + HCl from the coprecipitate and the solid particles. The precipitate is heated at 400 deg. C and digested in aqua regia. Na2SO3 and NaNO2 have been applied to obtain Pu+4 valence in 0.5-1 N HNO3 for different samples. Plutonium and thorium are coabsorbed on anionic resin from 8 N HNO3. The column is eluated with 8 N HNO3 containing fresh NaNO2 to keep Pu+4 valence for uranium decontamination. The system of the column is changed from 8 N HNO3 to concentrated HCl with 50 ml conc. HCl containing a few milligram NaNO2. Further decontamination of thorium was achieved by eluation with concentrated HCl instead of 9 N HCl. The plutonium is successfully stripped by H2O, NaOH, 2 N HNO3 and 0.5 N HNO3 containing 0.01 M NaNO3. The chemical yield of plutonium for a 200 litres-seawater sample is 60-80%. The resolution of the electroplated thin source is very good. (author)

  14. Analyses of sulfonamide antibiotics by a successive anion- and cation-selective injection coupled to microemulsion electrokinetic chromatography.

    Science.gov (United States)

    Lin, Yun-Ta; Liu, Yu-Wei; Cheng, Yi-Jie; Huang, Hsi-Ya

    2010-07-01

    In this study, an MEEKC was used to detect and analyze nine sulfonamide antibiotics. Owing to an insufficient sensitivity of on-column UV detection, a field-amplified sample injection, successive anion- and cation-selective injection, was used for the on-line concentration of the nine antibiotics. In the successive anion- and cation-selective injection mode, a leading water plug was introduced prior to anion injection, and then an acidic plug followed by a terminal water plug had to be used before subsequent cation injection. The results indicated some sulfonamides (sulfamonomethoxine, sulfamethazine, sulfamerazine and sulfadiazine) were determined as split signals in pairs, and this was likely due to the use of a longer acid plug (360 s) which caused the sulfonamide anions and cations to be stacked in two distinct zones of the leading water and acid plugs. Meanwhile, all the sulfonamides that were introduced either by anion or cation injection were stacked within the leading water plug when a shorter acid plug (210 s) was used. As a result, the nine sulfonamides were determined as single and symmetrical peaks with low LODs (0.9-4.2 microg/L). Furthermore, the MEEKC method was successfully applied for the detection of trace sulfonamide residues in several food and water samples. PMID:20593402

  15. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    1983-10-01

    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 in the present report: (1) release of acids, radionuclides or chemically aggressive species through radiolytic attack on the functional group, (2) radiolytic generation/uptake of corrosive or combustible gases, (3) effect of irradiation on solidification of resins in cement. Special consideration was placed on external variables such as radiation dose rate, resin chemical loading and moisture conditions, accessibility to atmospheric oxygen, and interactions in multicomponent systems. Such variables may affect the correspondence between laboratory results and field performance. 40 references, 24 figures, 28 tables.

  16. Artificial liver support for postoperative hepatic failure with anion exchange resin (BR-601).

    OpenAIRE

    Sakagami,Kenichi; MIYAZAKI, MASASHI; Matsuoka, Junji; Shiozaki,Shigehiro; Saito, Shinya; Orita,Kunzo

    1986-01-01

    An artificial liver support system for plasma exchange and plasma perfusion through BR-601 resin using a membrane separator was applied to 5 patients with postoperative liver failure. Percent absorption of total and direct bilirubin, and of bile acids were 77.1 +/- 6.4, 78.4 +/- 6.1, and 93.4 +/- 3.6%, respectively, when 250 ml of plasma was treated. Percent reductions in total and direct bilirubin, and in bile acids were 24.5 +/- 5.8, 25.5 +/- 5.8 and 30.9 +/- 8.5%, respectively. In contrast...

  17. Boron enrichment by ion exchange with Dowex 1X8 anion resin

    International Nuclear Information System (INIS)

    An isotopic separation pilot plant with five ion exchange columns interconnected in series were designed and built in the IEN. The boric acid solution is introduced in the separation columns until it reaches a absorbing zone lenght which is sufficient to obtain the desired boron-10 isotopic concentration. The boric acid absorbing zone movement is provided by the injection of a diluted hydrochloric acid solution, which replces the boric acid troughout the columns to its total lenght. The enriched boron-10 and the depleted boron are located in the final boundary and in the initial position of the absorbing zones, respectively. (author). 6 refs

  18. Synthesis and anion exchange properties of a Zn/Ni double hydroxide salt with a guarinoite structure

    International Nuclear Information System (INIS)

    In this study, the first route to synthesize a compound with the guarinoite structure (Zn,Co,Ni)6(SO4)(OH,Cl)10.5H2O is reported. Zn/Ni guarinoite is obtained from the reaction of NiSO4.7H2O with solid ZnO in aqueous solution. The resulting green Zn/Ni guarinoite ((Zn3.52Ni1.63)(SO4)1.33(OH7.64).4.67H2O) was characterized by X-ray diffraction, infrared spectrometry, UV-Visible spectrometry and thermal analysis. It is shown that its structure is similar to the one described for the layered Zn sulfate hydroxide hydrate, i.e. brucite layers with 1/4 empty octahedra presenting tetrahedrally coordinated divalent atoms above and below the empty octahedra. Ni atoms are located in the octahedra and zinc atoms in tetrahedra and octahedra. In this structure the exchangeable anions are located at the apex of tetrahedra. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations show that the Zn/Ni guarinoite is composed of aggregates of hexagonal plates of several hundreds of nanometers. Due to its interest for industrial or environmental applications, the exchange of sulfate groups by carbonates has been investigated. Results show a limited exchange and a higher affinity of the Zn/Ni guarinoite for sulfates compared to carbonates. - Graphical abstract: SEM micrograph (secondary electrons) of the synthesized Zn/Ni guarinoite showing that aggregates are composed of small plate-like particles.

  19. Preparation of silica nanocomposite anion-exchange membranes with low vanadium-ion crossover for vanadium redox flow batteries

    International Nuclear Information System (INIS)

    Highlights: • The permeability of vanadium ions through the silica nanocomposite AEM (SNAEM) is ten times lower than that for Nafion 115. • The rates of self-discharge and capacity fading of the VRFB are substantially reduced with the use of the SNAEM. • The Coulombic and energy efficiencies are as high as 92% and 73%, respectively, at 40 mA cm−2. -- Abstract: Crossover of vanadium ions through the membranes of all-vanadium redox flow batteries (VRFB) is an issue that limits the performance of this type of flow battery. This paper reports on the preparation of a sol–gel derived silica nanocomposite anion exchange membrane (AEM) for VRFBs. The EDS and FT-IR characterizations confirm the presence and the uniformity of the silica nanoparticles formed in the membrane via an in situ sol–gel process. The properties of the obtained membrane, including the ion-exchange capacity, the area resistance, and the water uptake, are evaluated and compared to the pristine AEM and the Nafion cation exchange membrane (CEM). The experimental results show that the permeability of the vanadium ions through the silica nanocomposite AEM is about 20% lower than that of the pristine AEM, and one order of magnitude lower than that of the Nafion CEM. As a result, the rates of self-discharge and the capacity fading of the VRFB are substantially reduced. The Coulombic and energy efficiencies at a current density of 40 mA cm−2 are, respectively, as high as 92% and 73%

  20. Artificial liver support for postoperative hepatic failure with anion exchange resin (BR-601.

    Directory of Open Access Journals (Sweden)

    Sakagami,Kenichi

    1986-10-01

    Full Text Available An artificial liver support system for plasma exchange and plasma perfusion through BR-601 resin using a membrane separator was applied to 5 patients with postoperative liver failure. Percent absorption of total and direct bilirubin, and of bile acids were 77.1 +/- 6.4, 78.4 +/- 6.1, and 93.4 +/- 3.6%, respectively, when 250 ml of plasma was treated. Percent reductions in total and direct bilirubin, and in bile acids were 24.5 +/- 5.8, 25.5 +/- 5.8 and 30.9 +/- 8.5%, respectively. In contrast, percent reductions in total and direct bilirubin, and in bile acids by plasma exchange were 30.9 +/- 13.3, 34.5 +/- 12.5 and 24.2 +/- 8.5%, respectively. The coma grade was improved in 4 out of 5 cases, but unfortunately the patients did not recover. In conclusion, plasma perfusion through BR-601 resin is expected to play a promising role in artificial liver support systems because of its capacity to absorb bilirubin and bile acids.

  1. Cationic Covalent Organic Frameworks: A Simple Platform of Anionic Exchange for Porosity Tuning and Proton Conduction.

    Science.gov (United States)

    Ma, Heping; Liu, Bailing; Li, Bin; Zhang, Liming; Li, Yang-Guang; Tan, Hua-Qiao; Zang, Hong-Ying; Zhu, Guangshan

    2016-05-11

    Mimicking proton conduction mechanism of Nafion to construct novel proton-conducting materials with low cost and high proton conductivity is of wide interest. Herein, we have designed and synthesized a cationic covalent organic framework with high thermal and chemical stability by combining a cationic monomer, ethidium bromide (EB) (3,8-diamino-5-ethyl-6-phenylphenanthridinium bromide), with 1,3,5-triformylphloroglucinol (TFP) in Schiff base reactions. This is the first time that the stable cationic crystalline frameworks allowed for the fabrication of a series of charged COFs (EB-COF:X, X = F, Cl, Br, I) through ion exchange processes. Exchange of the extra framework ions can finely modulate the COFs' porosity and pore sizes at nanoscale. More importantly, by introducing PW12O40(3-) into this porous cationic framework, we can greatly enhance the proton conductivity of ionic COF-based material. To the best of our knowledge, EB-COF:PW12 shows the best proton conductivity at room temperature among ever reported porous organic materials. PMID:27094048

  2. Arsenate Adsorption by Hydrous Ferric Oxide Nanoparticles Embedded in Cross-linked Anion Exchanger: Effect of the Host Pore Structure.

    Science.gov (United States)

    Li, Hongchao; Shan, Chao; Zhang, Yanyang; Cai, Jianguo; Zhang, Weiming; Pan, Bingcai

    2016-02-10

    Three composite adsorbents were fabricated via confined growth of hydrous ferric oxide (HFO) nanoparticles within cross-linked anion exchangers (NS) of different pore size distributions to investigate the effect of host pore structure on the adsorption of As(V). With the decrease in the average pore size of the NS hosts from 38.7 to 9.2 nm, the mean diameter of the confined HFO nanoparticles was lessened from 31.4 to 11.6 nm as observed by transmission electron microscopy (TEM), while the density of active surface sites was increased due to size-dependent effect proved by potentiometric titration. The adsorption capacity of As(V) yielded by Sips model was elevated from 24.2 to 31.6 mg/g via tailoring the pore size of the NS hosts, and the adsorption kinetics was slightly accelerated with the decrease of pore size in background solution containing 500 mg/L of Cl(-). Furthermore, the enhanced adsorption of As(V) was achieved over a wide pH range from 3 to 10, as well as in the presence of competing anions including Cl(-), SO4(2-), HCO3(-), NO3(-) (up to 800 mg/L), and PO4(3-) (up to 10 mg P/L). In addition, the fixed-bed working capacity increased from 2200 to 2950 bed volumes (BV) owing to the size confinement effect, which did not have adverse effect on the desorption of As(V) as the cumulative desorption efficiency reached 94% with 10 BV of binary solution (5% NaOH + 5% NaCl) for all the three adsorbents. Therefore, this study provided a promising strategy to regulate the reactivity of the nanoparticles via the size confinement effect of the host pore structure. PMID:26765396

  3. New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate

    KAUST Repository

    Chubar, Natalia

    2011-12-01

    Highly selective materials and effective technologies are needed to meet the increasingly stronger drinking water standards for targeted ionic species. Inorganic ion exchangers based on individual and mixed-metal hydrous oxides (or mixed adsorbents that contain inorganic ion exchangers in their composition) are adsorptive materials that are capable of lowering the concentrations of anionic contaminants, such as H 2AsO 4 -, H 3AsO 3, F -, Br -, BrO 3 -, HSeO 4 -, HSeO 3 - and H 3BO 3, to 10 μg/L or less. To achieve a higher selectivity towards arsenate, a new ion exchanger based on Mg-Al hydrous oxides was developed by a novel, cost-effective and environmentally friendly synthesis method via a non-traditional (alkoxide-free) sol-gel approach. The exceptional adsorptive capacity of the Mg-Al hydrous oxides towards H 2AsO 4 - (up to 200 mg[As]/gdw) is due to the high affinity of this sorbent towards arsenate (steep equilibrium isotherms) and its fast adsorption kinetics. Because of the mesoporous (as determined by N 2 adsorption and SEM) and layered (as determined by XRD and FTIR) structure of the ion-exchange material as well as the abundance of anion exchange sites (as determined by XPS and potentiometric titration) on its surface the material demonstrated very competitive (or very high) removal capacity towards other targeted anions, including fluoride, bromide, bromate, selenate, selenite, and borate. © 2011 IWA Publishing.

  4. 3-Methyltrimethylammonium poly(2,6-dimethyl-1,4-phenylene oxide) based anion exchange membrane for alkaline polymer electrolyte fuel cells

    Indian Academy of Sciences (India)

    K Hari Gopi; S Gouse Peera; S D Bhat; P Sridhar; S Pitchumani

    2014-06-01

    Hydroxyl ion (OH–) conducting anion exchange membranes based on modified poly (phenylene oxide) are fabricated for their application in alkaline polymer electrolyte fuel cells (APEFCs). In the present study, chloromethylation of poly(phenylene oxide) (PPO) is performed by aryl substitution rather than benzyl substitution and homogeneously quaternized to form an anion exchange membrane (AEM). 1H NMR and FT–IR studies reveal successful incorporation of the above groups in the polymer backbone. The membrane is characterized for its ion exchange capacity and water uptake. The membrane formed by these processes show good ionic conductivity and when used in fuel cell exhibited an enhanced performance in comparison with the state-of-the-art commercial AHA membrane. A peak power density of 111 mW/cm2 at a load current density of 250 mA/cm2 is obtained for PPO based membrane in APEFCs at 30 °C.

  5. Separation of carrier-free 90Y from 90Sr by ion exchange chromatography

    International Nuclear Information System (INIS)

    Separation of carrier free 90Y from fission product 90Sr by column chromatography was investigated using composite inorganic ion exchanger poly antimonic acid (PAA), which was developed in house. The optimum conditions of separation were obtained by studying the distribution coefficients for 90Y from different acid solutions (HNO3, HCl and H2SO4) in concentration range of 0.001 - 3 M on the sorbent. The results indicated that after loading 90S/90Y equilibrium solution, pure carrier free 90Y was obtained from the column using 1 M HNO3 solutions as eluent. The radiochemical purity of the separated 90Y was confirmed by studying its decay curve. (author)

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

    International Nuclear Information System (INIS)

    The separation and purification of uranium from either nitric acid or hydrochloric acid media can be accomplished by using either solvent extraction or ion-exchange. Over the past two years at Los Alamos, emerging programs are focused on recapturing the expertise required to do limited, small-quantity processing of enriched uranium. During this period of time, we have been investigating ion-addition, waste stream polishing is associated with this effort in order to achieve more complete removal of uranium prior to recycle of the acid. Extraction chromatography has been demonstrated to further polish the uranium from both nitric and hydrochloric acid media thus allowing for a more complete recovery of the actinide material and creation of less waste during the processing steps

  7. Alternative extraction of alkaloid anticarcinogens from Brazilian "vinca rosea" using Ion exchange chromatography

    Directory of Open Access Journals (Sweden)

    Sérgio Freire de Carvalhaes

    2002-01-01

    Full Text Available Extracts in ethanol and ethanol-ammonia of dried leaves from Catharanthus roseus, gathered at Rio de Janeiro state, were adsorbed in a strongly acidic cation exchange resin with sulfonic acid group, using the finite bath method, resulting in an alkaloid retained fraction and an acidic and neutral unretained fraction. High Performance Liquid Chromatography showed the isolation of the alkaloid fraction to be highly selective and with good performance, with an absence of alkaloids in the unretained fraction, while the retained fraction presented 1,54-6,35 mg/g of vindoline and 0,12-0,91 mg/g of vinblastine, common for an alkaloid-rich concentrate, usually obtained by classic extraction with several steps using solvents.

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

    Energy Technology Data Exchange (ETDEWEB)

    FitzPatrick, J.R.; Schake, B.S.; Murphy, J.; Holmes, K; West, M.H.

    1996-06-01

    The separation and purification of uranium from either nitric acid or hydrochloric acid media can be accomplished by using either solvent extraction or ion-exchange. Over the past two years at Los Alamos, emerging programs are focused on recapturing the expertise required to do limited, small-quantity processing of enriched uranium. During this period of time, we have been investigating ion-addition, waste stream polishing is associated with this effort in order to achieve more complete removal of uranium prior to recycle of the acid. Extraction chromatography has been demonstrated to further polish the uranium from both nitric and hydrochloric acid media thus allowing for a more complete recovery of the actinide material and creation of less waste during the processing steps.

  9. Efficiencies and Optimization of Weak Base Anion Ion-Exchange Resin for Groundwater Hexavalent Chromium Removal at Hanford

    International Nuclear Information System (INIS)

    The U.S. Department of Energy's (DOE's) contractor, CH2M HILL Plateau Remediation Company, has successfully converted a series of groundwater treatment facilities to use a new treatment resin that is delivering more than $3 million in annual cost savings and efficiency in treating groundwater contamination at the DOE Hanford Site in southeastern Washington State. During the production era, the nuclear reactors at the Hanford Site required a continuous supply of high-quality cooling water during operations. Cooling water consumption ranged from about 151,417 to 378,541 L/min (40,000 to 100,000 gal/min) per reactor, depending on specific operating conditions. Water from the Columbia River was filtered and treated chemically prior to use as cooling water, including the addition of sodium dichromate as a corrosion inhibitor. Hexavalent chromium was the primary component of the sodium dichromate and was introduced into the groundwater at the Hanford Site as a result of planned and unplanned discharges from the reactors starting in 1944. Groundwater contamination by hexavalent chromium and other contaminants related to nuclear reactor operations resulted in the need for groundwater remedial actions within the Hanford Site reactor areas. Beginning in 1995, groundwater treatment methods were evaluated, leading to the use of pump-and-treat facilities with ion exchange using Dowex 21K, a regenerable, strong-base anion exchange resin. This required regeneration of the resin, which was performed offsite. In 2008, DOE recognized that regulatory agreements would require significant expansion for the groundwater chromium treatment capacity. As a result, CH2M HILL performed testing at the Hanford Site in 2009 and 2010 to demonstrate resin performance in the specific groundwater chemistry at different waste sites. The testing demonstrated that a weak-base anion, single-use resin, specifically ResinTech SIR-700 ®, was effective at removing chromium, had a significantly higher

  10. Efficiencies and Optimization of Weak Base Anion Ion-Exchange Resin for Groundwater Hexavalent Chromium Removal at Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Nesham, Dean O.; Ivarson, Kristine A.; Hanson, James P.; Miller, Charles W.; Meyers, P.; Jaschke, Naomi M.

    2014-02-03

    The U.S. Department of Energy’s (DOE’s) contractor, CH2M HILL Plateau Remediation Company, has successfully converted a series of groundwater treatment facilities to use a new treatment resin that is delivering more than $3 million in annual cost savings and efficiency in treating groundwater contamination at the DOE Hanford Site in southeastern Washington State. During the production era, the nuclear reactors at the Hanford Site required a continuous supply of high-quality cooling water during operations. Cooling water consumption ranged from about 151,417 to 378,541 L/min (40,000 to 100,000 gal/min) per reactor, depending on specific operating conditions. Water from the Columbia River was filtered and treated chemically prior to use as cooling water, including the addition of sodium dichromate as a corrosion inhibitor. Hexavalent chromium was the primary component of the sodium dichromate and was introduced into the groundwater at the Hanford Site as a result of planned and unplanned discharges from the reactors starting in 1944. Groundwater contamination by hexavalent chromium and other contaminants related to nuclear reactor operations resulted in the need for groundwater remedial actions within the Hanford Site reactor areas. Beginning in 1995, groundwater treatment methods were evaluated, leading to the use of pump-and-treat facilities with ion exchange using Dowex™ 21K, a regenerable, strong-base anion exchange resin. This required regeneration of the resin, which was performed offsite. In 2008, DOE recognized that regulatory agreements would require significant expansion for the groundwater chromium treatment capacity. As a result, CH2M HILL performed testing at the Hanford Site in 2009 and 2010 to demonstrate resin performance in the specific groundwater chemistry at different waste sites. The testing demonstrated that a weak-base anion, single-use resin, specifically ResinTech SIR-700 ®, was effective at removing chromium, had a significantly

  11. Single-Crystal-to-Single-Crystal Anion Exchange in a Gadolinium MOF: Incorporation of POMs and [AuCl4]−

    Directory of Open Access Journals (Sweden)

    Javier López-Cabrelles

    2016-04-01

    Full Text Available The encapsulation of functional molecules inside porous coordination polymers (also known as metal-organic frameworks, MOFs has become of great interest in recent years at the field of multifunctional materials. In this article, we present a study of the effects of size and charge in the anion exchange process of a Gd based MOF, involving molecular species like polyoxometalates (POMs, and [AuCl4]−. This post-synthetic modification has been characterized by IR, EDAX, and single crystal diffraction, which have provided unequivocal evidence of the location of the anion molecules in the framework.

  12. Evaluation and application of anion exchange resins to measure groundwater uranium flux at a former uranium mill site.

    Science.gov (United States)

    Stucker, Valerie; Ranville, James; Newman, Mark; Peacock, Aaron; Cho, Jaehyun; Hatfield, Kirk

    2011-10-15

    Laboratory tests and a field validation experiment were performed to evaluate anion exchange resins for uranium sorption and desorption in order to develop a uranium passive flux meter (PFM). The mass of uranium sorbed to the resin and corresponding masses of alcohol tracers eluted over the duration of groundwater installation are then used to determine the groundwater and uranium contaminant fluxes. Laboratory based batch experiments were performed using Purolite A500, Dowex 21K and 21K XLT, Lewatit S6328 A resins and silver impregnated activated carbon to examine uranium sorption and extraction for each material. The Dowex resins had the highest uranium sorption, followed by Lewatit, Purolite and the activated carbon. Recoveries from all ion exchange resins were in the range of 94-99% for aqueous uranium in the environmentally relevant concentration range studied (0.01-200 ppb). Due to the lower price and well-characterized tracer capacity, Lewatit S6328 A was used for field-testing of PFMs at the DOE UMTRA site in Rifle, CO. The effect on the flux measurements of extractant (nitric acid)/resin ratio, and uranium loading were investigated. Higher cumulative uranium fluxes (as seen with concentrations>1 ug U/gram resin) yielded more homogeneous resin samples versus lower cumulative fluxes (<1 ug U/gram resin), which caused the PFM to have areas of localized concentration of uranium. Resin homogenization and larger volume extractions yield reproducible results for all levels of uranium fluxes. Although PFM design can be improved to measure flux and groundwater flow direction, the current methodology can be applied to uranium transport studies. PMID:21798572

  13. Cromatografia de troca-iônica aplicada ao isolamento da fração ácida do óleo de copaíba (Copaifera multijuga) e da sacaca (Croton cajucara) Ion exchange chromatography applied to the fractionation of the copaíba oil (Copaifera multijuga) and sacaca (Croton cajucara) extracts

    OpenAIRE

    Amaro Gomes Barreto Júnior; Evaristo Chalbaud Biscaia Junior; Valdir Florêncio da Veiga Junior; Angelo C. Pinto; Sergio Freire de Carvalhaes; Maria Aparecida M. Maciel

    2005-01-01

    Plant extracts are usually complex mixtures which contain several molecules of different sizes with varied functional groups. Such extracts are a challenge to the chemist of natural products. Ion exchange chromatography in non-aqueous medium, used for separation of basic or acidic fractions from plant extracts, is an important unit operation in preparative scale separations. Anionic macroporous resin in non-aqueous medium was used with success in this study for separation of the acid fraction...

  14. Mitigating arsenic crisis in the developing world: role of robust, reusable and selective hybrid anion exchanger (HAIX).

    Science.gov (United States)

    German, Michael; Seingheng, Hul; SenGupta, Arup K

    2014-08-01

    In trying to address the public health crisis from the lack of potable water, millions of tube wells have been installed across the world. From these tube wells, natural groundwater contamination from arsenic regularly puts at risk the health of over 100 million people in South and Southeast Asia. Although there have been many research projects, awards and publications, appropriate treatment technology has not been matched to ground level realities and water solutions have not scaled to reach millions of people. For thousands of people from Nepal to India to Cambodia, hybrid anion exchange (HAIX) resins have provided arsenic-safe water for up to nine years. Synthesis of HAIX resins has been commercialized and they are now available globally. Robust, reusable and arsenic-selective, HAIX has been in operation in rural communities over numerous cycles of exhaustion-regeneration. All necessary testing and system maintenance is organized by community-level water staff. Removed arsenic is safely stored in a scientifically and environmentally appropriate manner to prevent future hazards to animals or people. Recent installations have shown the profitability of HAIX-based arsenic treatment, with capital payback periods of only two years in ideal locations. With an appropriate implementation model, HAIX-based treatment can rapidly scale and provide arsenic-safe water to at-risk populations. PMID:24321388

  15. A pilot-scale evaluation of magnetic ion exchange treatment for removal of natural organic material and inorganic anions.

    Science.gov (United States)

    Boyer, Treavor H; Singer, Philip C

    2006-08-01

    The objective of this research was to evaluate a magnetic ion exchange process (MIEX) for the removal of natural organic material (NOM) and bromide on a continuous-flow pilot-scale basis under different operating conditions and raw water characteristics. The most important operating variable was the effective resin dose (ERD), which is the product of the steady-state resin concentration in the contactor and the regeneration ratio. The raw water employed in this study had a moderate concentration of ultraviolet (UV)-absorbing substances and dissolved organic carbon (DOC), and a low turbidity, alkalinity, and concentration of competing anionic species. Experiments were conducted using the ambient raw water and raw water spiked with bromide, chloride, and sulfate. Substantial removal of UV-absorbing substances and DOC was achieved at ERDs as low as 0.16mL/L. Moderate bromide removal was achieved, depending on the ERD. Increasing the sulfate concentration resulted in decreased removal of UV-absorbing substances, DOC, and bromide. Consistent results were observed between the continuous-flow pilot plant tests and batch equilibrium studies. PMID:16844182

  16. Oxygen evolution reaction characteristics of synthetic nickel-cobalt-oxide electrodes for alkaline anion-exchange membrane water electrolysis

    Science.gov (United States)

    Koo, Tae Woo; Park, ChanSu; Kim, Yang Do; Lee, Dooyong; Park, Sungkyun; Lee, Jae Ho; Choi, Sung Mook; Choi, Chul Young

    2015-11-01

    A polymer electrolyte membrane water electrolysis system can produce high-purity hydrogen gases in a highly efficient manner. However, the level of hydrogen gas production is still small. In addition, noble-metal catalysts for the reaction in acidic environments, as well as an additional drying step to remove water contained in the hydrogen, are required. Therefore, water electrolysis system with high efficiency and lower cost, an alkaline anion-exchange membrane system that can produce high-purity hydrogen without a noble-metal catalyst, is needed. Nano-size NiCo2O4 powders were prepared by using a sol-gel method to achieve an efficient and economical water electrolysis system. When the powder was calcined at 450 °C, the crystallinity and the cyclic voltammogram measurement showed the best values. In addition, the 15-wt.% polytetrafluoroethylene mixed NiCo2O4 powders exhibited the largest cyclic voltammetry active area and the highest oxygen evolution reaction activity with the appropriate stability.

  17. Quaternized adamantane-containing poly(aryl ether ketone) anion exchange membranes for vanadium redox flow battery applications

    Science.gov (United States)

    Zhang, Bengui; Zhang, Shouhai; Weng, Zhihuan; Wang, Guosheng; Zhang, Enlei; Yu, Ping; Chen, Xiaomeng; Wang, Xinwei

    2016-09-01

    Quaternized adamantane-containing poly(aryl ether ketone) anion exchange membranes (QADMPEK) are prepared and investigated for vanadium redox flow batteries (VRFB) application. The bulky, rigid and highly hydrophobic adamantane segment incorporated into the backbone of membrane material makes QADMPEK membranes have low water uptake and swelling ratio, and the as-prepared membranes display significantly lower permeability of vanadium ions than that of Nafion117 membrane. As a consequence, the VRFB cell with QADMPEK-3 membrane shows higher coulombic efficiency (99.4%) and energy efficiency (84.0%) than those for Nafion117 membrane (95.2% and 80.5%, respectively) at the current density of 80 mA cm-2. Furthermore, at a much higher current density of 140 mA cm-2, QADMPEK membrane still exhibits better coulombic efficiency and energy efficiency than Nafion117 membrane (coulombic efficiency 99.2% vs 96.5% and energy efficiency 76.0% vs 74.0%). Moreover, QADMPEK membranes show high stability in in-situ VRFB cycle test and ex-situ oxidation stability test. These results indicate that QADMPEK membranes are good candidates for VRFB applications.

  18. Dissolved organic matter removal using magnetic anion exchange resin treatment on biological effluent of textile dyeing wastewater.

    Science.gov (United States)

    Fan, Jun; Li, Haibo; Shuang, Chendong; Li, Wentao; Li, Aimin

    2014-08-01

    This study investigated the removal of dissolved organic matter (DOM) from real dyeing bio-treatment effluents (DBEs) with the use of a novel magnetic anion exchange resin (NDMP). DOMs in two typical DBEs were fractionized using DAX-8/XAD-4 resin and ultrafiltration membranes. The hydrophilic fractions and the low molecular weight (MW) (50%) of DOMs for the two effluents. The hydrophilic and low MW fractions of both effluents were the greatest contributors of specific UV254 absorbance (SUVA254), and the SUVA254 of DOM fractions decreased with hydrophobicity and MW. Two DBEs exhibited acute and chronic biotoxicities. Both acute and chronic toxicities of DOM fractions increased linearly with the increase of SUVA254 value. Kinetics of dissolved organic carbon (DOC) removal via NDMP treatment was performed by comparing it with that of particle active carbon (PAC). Results indicated that the removal of DOC from DBEs via NDMP was 60%, whereas DOC removals by PAC were lower than 15%. Acidic organics could be significantly removed with the use of NDMP. DOM with large MW in DBE could be removed significantly by using the same means. Removal efficiency of NDMP for DOM decreased with the decrease of MW. Compared with PAC, NDMP could significantly reduce the acute and chronic bio-toxicities of DBEs. NaCl/NaOH mixture regenerants, with selected concentrations of 10% NaCl (m/m)/1% NaOH (m/m), could improve desorption efficiency. PMID:25108712

  19. Ion Mobility Spectrometry-Hydrogen Deuterium Exchange Mass Spectrometry of Anions: Part 3. Estimating Surface Area Exposure by Deuterium Uptake.

    Science.gov (United States)

    Khakinejad, Mahdiar; Kondalaji, Samaneh Ghassabi; Donohoe, Gregory C; Valentine, Stephen J

    2016-03-01

    Gas-phase hydrogen deuterium exchange (HDX), collision cross section (CCS) measurement, and molecular dynamics simulation (MDS) techniques were utilized to develop and compare three methods for estimating the relative surface area exposure of separate peptide chains within bovine insulin ions. Electrosprayed [M - 3H](3-) and [M - 5H](5-) insulin ions produced a single conformer type with respective collision cross sections of 528 ± 5 Å(2) and 808 ± 2 Å(2). [M - 4H](4-) ions were comprised of more compact (Ω = 676 ± 3 Å(2)) and diffuse (i.e., more elongated, Ω = 779 ± 3 Å(2)) ion conformer types. Ions were subjected to HDX in the drift tube using D2O as the reagent gas. Collision-induced dissociation was used to fragment mobility-selected, isotopically labeled [M - 4H](4-) and [M - 5H](5-) ions into the protein subchains. Deuterium uptake levels of each chain can be explained by limited inter-chain isotopic scrambling upon collisional activation. Using nominal ion structures from MDS and a hydrogen accessibility model, the deuterium uptake for each chain was correlated to its exposed surface area. In separate experiments, the per-residue deuterium content for the protonated and deprotonated ions of the synthetic peptide KKDDDDDIIKIIK were compared. The differences in deuterium content indicated the regional HDX accessibility for cations versus anions. Using ions of similar conformational type, this comparison highlights the complementary nature of HDX data obtained from positive- and negative-ion analysis. PMID:26620531

  20. Isotopic exchange during derivatization of platelet activating factor for gas chromatography-mass spectrometry

    International Nuclear Information System (INIS)

    One approach to the quantitative analysis of platelet activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycerol-3-phosphocholine; also referred to as AGEPC, alkyl glyceryl ether phosphocholine) is hydrolytic removal of the phosphocholine group and conversion to an electron-capturing derivative for gas chromatography-negative ion mass spectrometry. [2H3]Acetyl-AGEPC has been commonly employed as an internal standard. When 1-hexadecyl-2-[2H3]acetyl glycerol (obtained by enzymatic hydrolysis of [2H3]-C16:0 AGEPC) is treated with pentafluorobenzoyl chloride at 120 degrees C, the resulting 3-pentafluorobenzoate derivative shows extensive loss of the deuterium label. This exchange is evidently acid-catalyzed since derivatization of 1-hexadecyl-2-acetyl glycerol under the same conditions in the presence of a trace of 2HCl results in the incorporation of up to three deuterium atoms. Isotope exchange can be avoided if the reaction is carried out at low temperature in the presence of base. Direct derivatization of [2H3]-C16:0 AGEPC by treatment with pentafluorobenzoyl chloride or heptafluorobutyric anhydride also results in loss of the deuterium label. The use of [13C2]-C16:0 AGEPC as an internal standard is recommended for rigorous quantitative analysis

  1. Resolution of Enantiomers of (RS)-Baclofen by Ligand-Exchange Thin-Layer Chromatography.

    Science.gov (United States)

    Singh, Manisha; Malik, Poonam; Bhushan, Ravi

    2016-05-01

    A new chromatographic method has been developed for direct enantioresolution of (RS)-baclofen by ligand-exchange thin-layer chromatography (TLC) adopting two different approaches; (A) TLC plates were prepared by mixing the ligand exchange reagents (LER) with silica gel slurry and the chromatograms were developed with different achiral solvents or solvents having no chiral additive, and (B) the LER consisting of Cu(II)-l-amino acid complex was used as chiral mobile phase additive and the plain plates of silica gel having no chiral selector were used. Cu(II) acetate and fourl-amino acids (namely,l-tryptophan,l-histidine,l-proline andl-phenylalanine) were used for the preparation of LERs. Spots were located by the use of iodine vapor. Effect of temperature and the mole ratio of Cu(II)-to-amino acid on enantioresolution were also studied. The results for the two methods have been compared, and the issue of involvement of the Cu(II) cation for the best performance of the two methods has been discussed with respect to the same mobile phase.l-Trp proved to be a good ligand using a common mobile phase in each case. PMID:26896346

  2. Pilot-scale ion-exchange centrifugal partition chromatography: purification of sinalbin from white mustard seeds.

    Science.gov (United States)

    Toribio, Alix; Nuzillard, Jean-Marc; Pinel, Benoît; Boudesocque, Leslie; Lafosse, Michel; De La Poype, François; Renault, Jean-Hugues

    2009-06-01

    The purification of p-hydroxybenzylglucosinolate (sinalbin) on a multigram scale from a crude aqueous extract of white mustard seeds (Sinapis alba var. concerta) was successfully achieved by scaling up a strong ion-exchange centrifugal partition chromatography (SIXCPC) laboratory procedure. Thus, the one-step sinalbin purification was performed with 2.35 g of crude extract in approximately 170 min (830 mg/h) up to 70.3 g in approximately 160 min (26.3 g/h) by switching from a 200 mL laboratory scale column to a 5.7 L pilot-scale column. The required biphasic solvent system contained ethyl acetate, n-butanol, and water in 3:2:5 v/v/v proportions, Aliquat 336 (trioctylmethyl ammonium chloride) was added to the organic stationary phase (80 mM) and acted as ion-exchanger. Potassium iodide in the aqueous mobile phase (80 mM) was used as sinalbin displacer. The 28.5 mass scale factor arose from the increase in mobile phase flow-rate (from 2 to 50 mL/min), from the higher mass of injected white mustard seed extract (from 12 to 350 g), and from the calculated productivity (from 830 mg to 26.3 g). These results demonstrate that industry scale production of glucosinolates is easily performed by SIXCPC, thus providing pure reference standards for pharmacology studies. PMID:19479767

  3. Preparation of 161Tb nuclide using neutron irradiation method and ion exchange chromatography

    International Nuclear Information System (INIS)

    Using Xi'an pulsed reactor as neutron source, the production method of 161Tb was established. The influence of composition and mass of the target material on the productivity of 161Tb was investigated. In order to acquire purity 161Tb, an ion exchange chromatography method for Tb separation from the target material was studied. The influence of some factors such as length of resin bed, pH of eluent, amount of matrix Gd3+ and temperature on the separation was investigated using Dowex50 cation exchange resin. The results were showed that the composition and mass of the Gd2O3 target material obviously influenced the productivity of 161Tb, isotope enriched target material was optical choose for 161Tb production. Conditions such as matrix amount and length of resin bed had few effects on the separation of Tb within a small range, however, pH of eluent and temperature markedly affected the separation. The optimized separation condition for mixture solution of Gd3+, Tb3+ and Dy3+ was that 17.50 cm as length of resin bed, matrix amount of 50 mg, 0.20 mol/L 2- HIBA as elution, pH=3.80 and pH=4.00 for pH of Tb and Dy eluent, respectively, temperature higher than 25℃. Under the optimized condition, the recovery of Tb was higher than 95% and decontamination factor of Tb to Gd is higher than 10000. (authors)

  4. The use of ion exchange chromatography in the cyclotron production of the radioisotopes 85Sr, 54Mn, 57Co and 109Cd

    International Nuclear Information System (INIS)

    This dissertation shows the successful application of ion exchange chromatography to the isolation of carrier free cyclotron produced radioisotopes. A simple method is presented for the isolation of 85Sr from a 10 g rubidium chloride target. Cation exchange with AG50-X12 is used to retain 85Sr from a bombarded target dissolved in 0.1 mol/dm3 hydrochloric acid. Rubidium is effectively eluted with 0.5 mol/dm3 hydrochloric acid and trace impurities such as copper, iron and 65Zn are eluted with 0.5 mol/dm3 hydrochloric acid/φ=0.95 acetone (where φ is the volume fraction of acetone). Strontium-85 is eluted in nearly 100% yield with 3.0 mol/dm3 nitric acid. The isolation of 54Mn, 57Co and 109Cd from a composite iron-silver target is performed with AG50-X4 cation exchange resin in a hydrochloric acid-acetone medium subsequent to the removal of silver by reduction with hydrazine hydrate. Cadmium-109 is eluted with 0.1 mol/dm3 hydrochloric acid/φ=0.80 acetone and is further refined by absorption onto a AG1-X8 anion exchange column and subsequent washing with 0.25 mol/dm3 nitric acid/0.1 mol/dm3 hydrobromic acid. The elution of copper, iron, 65Zn and other impurities from the cation exhanger is performed with 0.5 mol/dm3 hydrochloric acid/φ=0.83 acetone. Cobalt-57 is quantitively eluted with 0.35 mol/dm3 hydrochloric acid/φ=0.90 acetone, and 54Mn, the remaining element on the column, is recovered with 3.0 mol/dm3 hydrochloric acid

  5. Recent Advances in Solid Catalysts Obtained by Metalloporphyrins Immobilization on Layered Anionic Exchangers: A Short Review and Some New Catalytic Results

    Directory of Open Access Journals (Sweden)

    Shirley Nakagaki

    2016-02-01

    Full Text Available Layered materials are a very interesting class of compounds obtained by stacking of two-dimensional layers along the basal axis. A remarkable property of these materials is their capacity to interact with a variety of chemical species, irrespective of their charge (neutral, cationic or anionic. These species can be grafted onto the surface of the layered materials or intercalated between the layers, to expand or contract the interlayer distance. Metalloporphyrins, which are typically soluble oxidation catalysts, are examples of molecules that can interact with layered materials. This work presents a short review of the studies involving metalloporphyrin immobilization on two different anionic exchangers, Layered Double Hydroxides (LDHs and Layered Hydroxide Salts (LHSs, published over the past year. After immobilization of anionic porphyrins, the resulting solids behave as reusable catalysts for heterogeneous oxidation processes. Although a large number of publications involving metalloporphyrin immobilization on LDHs exist, only a few papers have dealt with LHSs as supports, so metalloporphyrins immobilized on LHSs represent a new and promising research field. This work also describes new results on an anionic manganese porphyrin (MnP immobilized on Mg/Al-LDH solids with different nominal Mg/Al molar ratios (2:1, 3:1 and 4:1 and intercalated with different anions (CO32− or NO3−. The influence of the support composition on the MnP immobilization rates and the catalytic performance of the resulting solid in cyclooctene oxidation reactions will be reported.

  6. Recent Advances in Solid Catalysts Obtained by Metalloporphyrins Immobilization on Layered Anionic Exchangers: A Short Review and Some New Catalytic Results.

    Science.gov (United States)

    Nakagaki, Shirley; Mantovani, Karen Mary; Machado, Guilherme Sippel; Castro, Kelly Aparecida Dias de Freitas; Wypych, Fernando

    2016-01-01

    Layered materials are a very interesting class of compounds obtained by stacking of two-dimensional layers along the basal axis. A remarkable property of these materials is their capacity to interact with a variety of chemical species, irrespective of their charge (neutral, cationic or anionic). These species can be grafted onto the surface of the layered materials or intercalated between the layers, to expand or contract the interlayer distance. Metalloporphyrins, which are typically soluble oxidation catalysts, are examples of molecules that can interact with layered materials. This work presents a short review of the studies involving metalloporphyrin immobilization on two different anionic exchangers, Layered Double Hydroxides (LDHs) and Layered Hydroxide Salts (LHSs), published over the past year. After immobilization of anionic porphyrins, the resulting solids behave as reusable catalysts for heterogeneous oxidation processes. Although a large number of publications involving metalloporphyrin immobilization on LDHs exist, only a few papers have dealt with LHSs as supports, so metalloporphyrins immobilized on LHSs represent a new and promising research field. This work also describes new results on an anionic manganese porphyrin (MnP) immobilized on Mg/Al-LDH solids with different nominal Mg/Al molar ratios (2:1, 3:1 and 4:1) and intercalated with different anions (CO₃(2-) or NO₃(-)). The influence of the support composition on the MnP immobilization rates and the catalytic performance of the resulting solid in cyclooctene oxidation reactions will be reported. PMID:26938518

  7. Separation of 99TcO4- ions from actual reprocessing waste solution by poly (4-vinylpyridine-DVB) based anion exchangers

    International Nuclear Information System (INIS)

    Batch uptake of 99TcO4- ions from actual reprocessing waste solution was studied using three strong-base anion exchange resins prepared by quaternization of poly(4-vinylpyridine-DVB) with different alkyl (-CH3, -C2H5, and -n-C4H9) halides and two commercially available strong base anion exchange resins. Batch results showed that the resin with n-butyl group on the pyridine nitrogen has higher affinity for 99TcO4- ions. Excellent column performance of the resin for separation of 99TcO4- ions from such solution is established. Elution of 99TcO4- ions was carried out using 6 M HNO3 solution. (author)

  8. Heat resistance of the nuclear-quality hydroxide-form highly basic (type 1) anion exchange resin Varion AT-N

    International Nuclear Information System (INIS)

    The heat resistance of the Hungarian made nuclear-quality hydroxide-form highly basic (type 1) anion exchange resin Varion AT-N was studied under static conditions at temperatures 40 deg C, 60 deg C and 80 deg C. Subject to examinations was the deterioration of the resin grains as well as the change in capacity and replaceable chloride content as a function of the temperature and time. Conclusions in respect to the very slight changes in the resin were drawn from the analytical results of the aqueous extract. The results have shown that the deterioration of the anion exchange resin Varion AT-N(OH) is not significant even at 80 deg C. The magnitude of the calculated disintegration-rate constants agrees with the literature data. (author)

  9. Probing the Complementarity of FAIMS and Strong Cation Exchange Chromatography in Shotgun Proteomics

    Science.gov (United States)

    Creese, Andrew J.; Shimwell, Neil J.; Larkins, Katherine P. B.; Heath, John K.; Cooper, Helen J.

    2013-03-01

    High field asymmetric waveform ion mobility spectrometry (FAIMS), also known as differential ion mobility spectrometry, coupled with liquid chromatography tandem mass spectrometry (LC-MS/MS) offers benefits for the analysis of complex proteomics samples. Advantages include increased dynamic range, increased signal-to-noise, and reduced interference from ions of similar m/ z. FAIMS also separates isomers and positional variants. An alternative, and more established, method of reducing sample complexity is prefractionation by use of strong cation exchange chromatography. Here, we have compared SCX-LC-MS/MS with LC-FAIMS-MS/MS for the identification of peptides and proteins from whole cell lysates from the breast carcinoma SUM52 cell line. Two FAIMS approaches are considered: (1) multiple compensation voltages within a single LC-MS/MS analysis (internal stepping) and (2) repeat LC-MS/MS analyses at different and fixed compensation voltages (external stepping). We also consider the consequence of the fragmentation method (electron transfer dissociation or collision-induced dissociation) on the workflow performance. The external stepping approach resulted in a greater number of protein and peptide identifications than the internal stepping approach for both ETD and CID MS/MS, suggesting that this should be the method of choice for FAIMS proteomics experiments. The overlap in protein identifications from the SCX method and the external FAIMS method was ~25 % for both ETD and CID, and for peptides was less than 20 %. The lack of overlap between FAIMS and SCX highlights the complementarity of the two techniques. Charge state analysis of the peptide assignments showed that the FAIMS approach identified a much greater proportion of triply-charged ions.

  10. Anion- or Cation-Exchange Membranes for NaBH4/H2O2 Fuel Cells?

    Directory of Open Access Journals (Sweden)

    César A. C. Sequeira

    2012-07-01

    Full Text Available Direct borohydride fuel cells (DBFC, which operate on sodium borohydride (NaBH4 as the fuel, and hydrogen peroxide (H2O2 as the oxidant, are receiving increasing attention. This is due to their promising use as power sources for space and underwater applications, where air is not available and gas storage poses obvious problems. One key factor to improve the performance of DBFCs concerns the type of separator used. Both anion- and cation-exchange membranes may be considered as potential separators for DBFC. In the present paper, the effect of the membrane type on the performance of laboratory NaBH4/H2O2 fuel cells using Pt electrodes is studied at room temperature. Two commercial ion-exchange membranes from Membranes International Inc., an anion-exchange membrane (AMI-7001S and a cation-exchange membrane (CMI-7000S, are tested as ionic separators for the DBFC. The membranes are compared directly by the observation and analysis of the corresponding DBFC’s performance. Cell polarization, power density, stability, and durability tests are used in the membranes’ evaluation. Energy densities and specific capacities are estimated. Most tests conducted, clearly indicate a superior performance of the cation-exchange membranes over the anion-exchange membrane. The two membranes are also compared with several other previously tested commercial membranes. For long term cell operation, these membranes seem to outperform the stability of the benchmark Nafion membranes but further studies are still required to improve their instantaneous power load.

  11. Solid-phase methods for sequencing of nucleic acids I. Simultaneous sequencing of different oligodeoxyribonucleotides using a new, mechanically stable anion-exchange paper.

    OpenAIRE

    Rosenthal, A.; Schwertner, S; Hahn, V; Hunger, H. D.

    1985-01-01

    A solid-phase method for simultaneous sequencing of large numbers of oligodeoxyribonucleotides has been developed using a new, mechanically stable anion-exchange paper. The excellent mechanical properties of the polymer allow the processing of several paper segments in one reaction vessel or to carry out all necessary operations on a larger area of the paper. In addition, DNA material can be chemically eluted from the new carrier during the piperidine reaction, thus avoiding salt elution of D...

  12. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters

    OpenAIRE

    Ball James W; Nordstrom D Kirk; Schoonen Martin AA; Druschel Greg K; Xu Yong; Cohn Corey A

    2003-01-01

    A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange resin Bio-Rad™ AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted w...

  13. Characterization of Anion Exchange Membrane Containing Epoxy Ring and C–Cl Bond Quaternized by Various Amine Groups for Application in Fuel Cells

    OpenAIRE

    Sung Kuk Jeong; Ju Sung Lee; Sahng Hyuck Woo; Jin Ah Seo; Byoung Ryul Min

    2015-01-01

    Anion exchange membranes were synthesized from different compositions of glycidyl methacrylate (GMA) and vinylbenzyl chloride (VBC), with constant content of divinyl benzene (DVB) by radical polymerization using benzoyl peroxide (BPO) on non-woven polyethylene terephthalate (PET) substrate. Polymerized membranes were then quaternized by soaking in trimethylamine (TMA), triethylamine (TEA), tripropylamine (TPA), and 1,4-diazabicyclo [2.2.2] octane (DABCO). Characteristics of membranes were con...

  14. Characterization of Anion Exchange Membrane Containing Epoxy Ring and C–Cl Bond Quaternized by Various Amine Groups for Application in Fuel Cells

    OpenAIRE

    Sung Kuk Jeong; Ju Sung Lee; Sahng Hyuck Woo; Jin Ah Seo; Byoung Ryul Min

    2015-01-01

    Anion exchange membranes were synthesized from different compositions of glycidyl methacrylate (GMA) and vinylbenzyl chloride (VBC), with constant content of divinyl benzene (DVB) by radical polymerization using benzoyl peroxide (BPO) on non-woven polyethylene terephthalate (PET) substrate. Polymerized membranes were then quaternized by soaking in trimethylamine (TMA), triethylamine (TEA), tripropylamine (TPA), and 1,4-diazabicyclo [2.2.2] octane (DABCO). Characteristics of membranes were co...

  15. Structural and microstructural changes during anion exchange of CoAl layered double hydroxides: an in situ X-ray powder diffraction study

    DEFF Research Database (Denmark)

    Johnsen, Rune; Krumeich, Frank; Norby, Poul

    2010-01-01

    Anion-exchange processes in cobalt-aluminium layered double hydroxides (LDHs) were studied by in situ synchrotron X-ray powder diffraction (XRPD). The processes investigated were CoAl-CO3 CoAl-Cl CoAl-CO3, CoAl-Cl CoAl-NO3 and CoAl-CO3 CoAl-SO4. The XRPD data show that the CoAl-CO3 CoAl-Cl process...

  16. Differential inhibition of AE1 and AE2 anion exchangers by oxonol dyes and by novel polyaminosterol analogs of the shark antibiotic squalamine.

    Science.gov (United States)

    Alper, S L; Chernova, M N; Williams, J; Zasloff, M; Law, F Y; Knauf, P A

    1998-01-01

    Oxonol and polyaminosterol drugs were examined as inhibitors of recombinant mouse AE1 and AE2 anion exchangers expressed in Xenopus laevis oocytes and were compared as inhibitors of AE1-mediated anion flux in red cells and in HL-60 cells that express AE2. The oxonols WW-781, diBA(5)C4, and diBA(3)C4 inhibited HL-60 cell Cl-/Cl- exchange with IC50 values from 1 to 7 microM, 100-1000 times less potent than their IC50 values for red cell Cl-/anion exchange. In Xenopus oocytes, diBA(5)C4 inhibited AE1-mediated Cl- efflux several hundred times more potently than that mediated by AE2. Several novel squalamine-related polyaminosterols were also evaluated as anion exchange inhibitors. In contrast to diBA(5)C4, polyaminosterol 1361 inhibited oocyte-expressed AE2 8-fold more potently than AE1 (IC50 0.6 versus 5.2 microM). The 3-fold less potent desulfo-analog, 1360, showed similar preference for AE2. It was found that 1361 also partially inhibited Cl- efflux from red cells, whereas neither polyaminosterol inhibited Cl efflux from HL60 cells. Thus, the oxonol diBA(5)C4 is >100-fold more potent as an inhibitor of AE1 than of AE2, whereas the polyaminosterols 1360 and 1361 are 8-fold more potent as inhibitors of AE2 than of AE1. Assay conditions and cell type influenced IC50 values for both classes of compounds. PMID:10353714

  17. Determination of chromium(VI) in water by PIXE analysis using ion exchange paper. Limit of detection and interference by coexisting anions

    International Nuclear Information System (INIS)

    Concerning the PIXE analysis of Cr(VI) in water using ion-exchange filters, the limit of detection (LOD) and the influence of matrix anions were investigated. In order to look for the experimental condition for obtaining the minimum LOD, we measured the Cr-Kα X-ray counts and background counts under the Kα X-ray peak as a function of the incident proton energy and the thickness of the Mylar absorber foil in front of the detector. To investigate the interference by coexisting anions, each of PO43-, SO42-, NO3-, Cl-, and F- ions and Cr(VI) ions were mixed in aqueous solutions and adsorbed on DE81-DEAE cellulose paper, a weakly basic anion exchanger with diethylaminoethyl functional groups. Then the filter samples were measured by PIXE using 2.5 MeV proton beams. We obtained a LOD of 0.16 μg or 8 ppb for 20 mL samples at a proton energy of 2.5 MeV and a Mylar film thickness of 50 or 100 μm. The experimental results on the mixed solutions indicated that NO3-, Cl-, and F- as coexisting ions didn't interfere significantly with determination of a 50 μg/L Cr(VI) concentration for 40 mL total solution volume, despite the total amount of anions was about 90% of ion exchange capacity of a filter. On the other hand, slight interferences by PO43- ions were observed. However, under the same condition, we found that if the total amount of SO42- ions was higher than 20% of ion exchange capacity, they induced significant interferences in determining Cr(VI). (author)

  18. Use of new tandem cation/anion exchange system with clinical-scale generators provides high specific volume solutions of technetium-99m and rhenium-188

    International Nuclear Information System (INIS)

    In this paper we describe the first application of our simple and inexpensive post-elution tandem cation/anion exchange column system which is based on generator elution with salts of weak acids such as ammonium acetate instead of saline solution to provide very high specific volume solutions of technetium-99m and rhenium-188 from clinical-scale molybdenum-99/technetium-99m generator prepared from low specific activity (n,y) molybdenum-99, and tungsten-188/rhenium-188 generators, respectively. Initial passage of the bolus through a strong cation exchange cartridge converts the ammonium acetate to acetic acid which is essentially not ionized at the acidic pH, allowing specific subsequent amine-type (QMA SepPak TM) anion exchange cartridge column trapping of the microscopic levels of the pertechnetate or perrhenate. Subsequent elution of the anion cartridge with a small volume (500 mCi/mL) from the alumina-based tungsten-188/rhenium-188 generator. (author)

  19. Chlorine isotope enrichment on a strong alkaline anion exchanger in dependence of type and concentration of the strange electrolytic solution

    International Nuclear Information System (INIS)

    Chlorine isotope enrichment for heterogenous ionexchange equilibria was studied. The dependence of element separation effects on the anion of the strange electrolyte (for same cation), on the cation of the strange electrolyte (for same anion), on the concentration of the strange electrolyte and also on the acetone: water ratio of the solvent was investigated. (orig./HBR)

  20. Compensatory role of inducible annexin A2 for impaired biliary epithelial anion-exchange activity of inflammatory cholangiopathy.

    Science.gov (United States)

    Kido, Osamu; Fukushima, Koji; Ueno, Yoshiyuki; Inoue, Jun; Jefferson, Douglas M; Shimosegawa, Tooru

    2009-12-01

    The peribiliary inflammation of cholangiopathy affects the physiological properties of biliary epithelial cells (cholangiocyte), including bicarbonate-rich ductular secretion. We revealed the upregulation of annexin A2 (ANXA2) in cholangiocytes in primary biliary cirrhosis (PBC) by a proteomics approach and evaluated its physiological significance. Global protein expression profiles of a normal human cholangiocyte line (H69) in response to interferon-gamma (IFNgamma) were obtained by two-dimensional electrophoresis followed by MALDI-TOF-MS. Histological expression patterns of the identified molecules in PBC liver were confirmed by immunostaining. H69 cells stably transfected with doxycyclin-inducible ANXA2 were subjected to physiological evaluation. Recovery of the intracellular pH after acute alkalinization was measured consecutively by a pH indicator with a specific inhibitor of anion exchanger (AE), 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS). Protein kinase-C (PKC) activation was measured by PepTag Assay and immunoblotting. Twenty spots that included ANXA2 were identified as IFNgamma-responsive molecules. Cholangiocytes of PBC liver were decorated by the unique membranous overexpression of ANXA2. Apical ANXA2 of small ducts of PBC was directly correlated with the clinical cholestatic markers and transaminases. Controlled induction of ANXA2 resulted in significant increase of the DIDS-inhibitory fraction of AE activity of H69, which was accompanied by modulation of PKC activity. We, therefore, identified ANXA2 as an IFNgamma-inducible gene in cholangiocytes that could serve as a potential histological marker of inflammatory cholangiopathy, including PBC. We conclude that inducible ANXA2 expression in cholangiocytes may play a compensatory role for the impaired AE activity of cholangiocytes in PBC in terms of bicarbonate-rich ductular secretion and bile formation through modulation of the PKC activity. PMID:19823170

  1. Effect of dissolved organic matter on nitrate-nitrogen removal by anion exchange resin and kinetics studies

    Institute of Scientific and Technical Information of China (English)

    Haiou Song; Zhijian Yao; Mengqiao Wang; Jinnan Wang; Zhaolian Zhu; Aimin Li

    2013-01-01

    The effects of dissolved organic matter (DOM) on the removal of nitrate-nitrogen from the model contaminated water have been investigated utilizing the strong base anion exchange resins.With the increase of gallic acid concentration from 0 to 400 mg/L,the adsorption amount of nitrate-nitrogen on the commercial resins,including D201,Purolite A 300 (A300) and Purolite A 520E (A520E),would significantly decrease.However,the presence of tannin acid has little impact on nitrate-nitrogen adsorption on them.Compared to D201 and A300 resins,A520E resin exhibited more preferable adsorption ability toward nitrate-nitrogen in the presence of competing organic molecules,such as gallic acid and tannin acid at greater levels in aqueous solution.Attractively,the equilibrium data showed that the adsorption isotherm of nitrate-nitrogen on A520E resin was in good agreement with Langmuir and Freundlich equations.The rate parameters for the intra particle diffusion have been estimated for the different initial concentrations.In batch adsorption processes,nitrate-nitrogen diffuse in porous adsorbent and rate process usually depends on t1/2 rather than the contact time.The pseudo first-and the second-order kinetic models fit better for nitrate-nitrogen adsorption onto A520E resin.The observations reported herein illustrated that A520E resin will be an excellent adsorbent for enhanced removal of nitrate-nitrogen from contaminated groundwater.

  2. Tandem anion and cation exchange solid phase extraction for the enrichment of micropollutants and their transformation products from ozonation in a wastewater treatment plant.

    Science.gov (United States)

    Deeb, Ahmad A; Schmidt, Torsten C

    2016-06-01

    The presence of organic micropollutants and their transformation products (TPs) from biotic and abiotic processes in aquatic environments is receiving intense public and scientific attention. Yet a suitable sample preparation method that would enable extraction and enrichment of a wide range of such compounds from water is missing. The focus of this paper was to develop an enhanced solid phase extraction (SPE) protocol which enabled isolation of parent compounds and low molecular weight transformation products (that are produced after treatment of water with ozone) from different water matrices. Ten SPE sorbents were evaluated with regard to their ability to extract acidic, neutral, and basic compounds from water at several pH values. Highest recoveries (91-99 %) for all analytes in pure water were obtained by combining strong anion and cation exchangers of two manufacturers in a tandem mode without pH adjustment. Tandem Oasis (MAX+MCX) was finally applied to extract the spiked analytes from tap water, surface water, and several wastewater samples. The efficiency of the used SPE procedure was examined using an optimized liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method using multiple reaction monitoring (MRM) mode. The occurrence of some of the investigated TPs in environmental water matrices was proven for the first time in this study. Method quantification limits (MQLs) for all compounds ranged from 3.7 to 15.3 ng/L in all matrices. Recoveries (%RE) were between 90 and 110 %. Intraday and interday precision, expressed as relative standard deviation, varied from 0.7 to 5.9 % and 1.8 to 10.3 %, respectively. Matrix effect (%ME) evaluation demonstrated that even complex sample matrices did not show significant ion suppression or enhancement. The applicability of the method was shown during two sampling campaigns at Ruhr river and a wastewater treatment plant (WWTP) equipped with an ozonation step after regular

  3. Rapid chiral separation and impurity determination of levofloxacin by ligand-exchange chromatography

    International Nuclear Information System (INIS)

    A sensitive, simple, and accurate method for determination of levofloxacin and its (R)-enantiomer was developed to determine the chiral impurity of levofloxacin in Cravit Tablets material by ligand-exchange high performance liquid chromatography. The effects of different kinds of ligands, concentration of ligands in mobile phase, organic modifier, pH of mobile phase, and temperature on enantioseparation were investigated and evaluated. Chiral separation was performed on a conventional C18 column, where the mobile phase consisted of a methanol-water solution (containing10 mmol L-1 L-leucine and 5 mmol L-1 copper sulfate) (88:12, v/v) and its flow-rate was set at 1.0 mL min-1. The conventional C18 column offers baseline separation of two enantiomers with a resolution of 2.4 in less than 20 min. Thermodynamic data (ΔΔH and ΔΔS) obtained by Van't Hoff plots revealed the chiral separation is an enthalpy-controlled process. The standard curves showed excellent linearity over the concentration range from 0.5 to 400 mg L-1 for levofloxacin and its (R)-enantiomer. The linear correlation equations are: y = 1.33 x 105 x + 6297 (r = 0.9991) and y = 1.34 x 105 x + 3565 (r = 0.9997), respectively. The relative standard deviation (RSD) of the method was below 2.3% (n = 3)

  4. Oxidation-labile subfraction of human plasma low density lipoprotein isolated by ion-exchange chromatography.

    Science.gov (United States)

    Shimano, H; Yamada, N; Ishibashi, S; Mokuno, H; Mori, N; Gotoda, T; Harada, K; Akanuma, Y; Murase, T; Yazaki, Y

    1991-05-01

    We isolated subfractions of human plasma low density lipoprotein (LDL) using ion-exchange chromatography. Plasma LDL from normolipidemic subjects were applied to a DEAE Sepharose 6B column. After elution of the bulk of LDL at 150 mM NaCl (the major fraction), the residual LDL was eluted at 500 mM NaCl and designated as the minor fraction. The minor fraction, only less than 1% of total LDL, tended to be somewhat similar in certain properties to oxidized LDL, e.g., an increased negative charge, higher protein/cholesterol ratio, and a higher flotation density than native LDL. These results were consistent with data reported by Avogaro et al. (1988. Arteriosclerosis. 8: 79-87). However, assays of 125I-labeled LDL binding activity for LDL receptors equal to that of the major fraction. Incorporation of [14C]oleate into cholesteryl ester [acyl-CoA:cholesterol acyltransferase (ACAT) activity] in mouse peritoneal macrophages incubated with the minor fraction was only slightly greater than that with the major fraction. Incubation of the minor fraction with 0.5 microM Cu2+ caused a remarkable stimulation of ACAT activity, while stimulation by the major fraction required incubation with 5 microM Cu2+, suggesting that the minor fraction was relatively labile to oxidation. The minor but definite presence of a plasma LDL subfraction more negative and susceptible to oxidation implicates the possibility of its association with atherogenesis. PMID:2072039

  5. Sodium citrate-assisted anion exchange strategy for construction of Bi{sub 2}O{sub 2}CO{sub 3}/BiOI photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Song, Peng-Yuan; Xu, Ming; Zhang, Wei-De, E-mail: zhangwd@scut.edu.cn

    2015-02-15

    Highlights: • Heterostructured Bi{sub 2}O{sub 2}CO{sub 3}/BiOI microspheres were prepared via anion exchange. • Sodium citrate-assisted anion exchange for construction of composite photocatalysts. • Bi{sub 2}O{sub 2}CO{sub 3}/BiOI composites show high visible light photocatalytic activity. - Abstract: Bi{sub 2}O{sub 2}CO{sub 3}/BiOI heterojuncted photocatalysts were constructed through a facile partial anion exchange strategy starting from BiOI microspheres and urea with the assistance of sodium citrate. The content of Bi{sub 2}O{sub 2}CO{sub 3} in the catalysts was regulated by modulating the amount of urea as a precursor, which was decomposed to generate CO{sub 3}{sup 2−} in the hydrothermal process. Citrate anion plays a key role in controlling the morphology and composition of the products. The Bi{sub 2}O{sub 2}CO{sub 3}/BiOI catalysts display much higher photocatalytic activity than pure BiOI and Bi{sub 2}O{sub 2}CO{sub 3} towards the degradation of rhodamine B (RhB) and bisphenol A (BPA). The enhancement of photocatalytic activity of the heterojuncted catalysts is attributed to the formation of p–n junction between p-BiOI and n-Bi{sub 2}O{sub 2}CO{sub 3}, which is favorable for retarding the recombination of photoinduced electron-hole pairs. Moreover, the holes are demonstrated to be the main active species for the degradation of RhB and BPA.

  6. Retention model of protein for mixed-mode interaction mechanism in ion exchange and hydrophobic interaction chromatography

    Institute of Scientific and Technical Information of China (English)

    WEI, Yin-Mao; LUO, Quan-Zhou; LIU,Tong; GENG, Xin-Du

    2000-01-01

    A unified retention equation of proteins was proved to be valid for a mixed-mode interaction mechanism in ion exchange chromatography (IEC) and hydrophobic interaction chromatography (HIC). The reason to form a “U” shape retention curve of proteins in both HIC and IEC was explained and the concentration range of the strongest elution ability for the mobile phase was determined with this equation. The parameters in this equation could be used to characterize the difference for either HIC or IEC adsorbents and the changes in the molecular conformation of proteins. With the parameters in this equation, the contributions of salt and water in the mobile phase to the protein retention in HIC and IEC were discussed,respectively. In addition, the comparison between the unified equation and Melander's three-parameter equation for mixedmode interaction chromatography was also investigated and better results were obtained in former equation.

  7. Ergot alkaloids in rye flour determined by solid phase cation-exchange and high pressure liquid chromatography with fluorescence detection

    OpenAIRE

    Storm, Ida Drejer; Have Rasmussen, Peter; Strobel, Bjarne W.; Hansen, Hans Christian Bruun

    2008-01-01

    Abstract Ergot alkaloids (EAs) are mycotoxins which are unavoidable contaminants of cereal products, particularly rye. A method was compiled employing clean-up by cation-exchange solid phase extraction, separation by high-pressure liquid chromatography under alkaline conditions and fluorescence detection. It is capable of separating and quantifying both C8-isomers of ergocornine, a-ergocryptine, ergocristine, ergonovine, and ergotamine. The average recovery was 61?10 % with limits ...

  8. Single vial sample preparation of markers of nerve agents by dispersive solid-phase extraction using magnetic strong anion exchange resins.

    Science.gov (United States)

    Singh, Varoon; Chinthakindi, Sridhar; Purohit, Ajay Kumar; Pardasani, Deepak; Tak, Vijay; Dubey, Devendra Kumar

    2015-05-22

    A sample preparation method involving extraction, enrichment and derivatization of acidic degradation products of nerve agents was developed using magnetic strong anion exchange resins (MSAX). The method was performed in a single vial involving magnetic dispersive solid phase extraction (MDSPE). Analytes were derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) in the presence of resins. MSAX were custom synthesized using Fe3O4 nanoparticles as core, 4-vinylpyridine-co-divinylbenzene as polymer shell and quaternary pyridinium function as anion-exchanger. Hydroxide ions were the counter-anions of MSAX to effectively capture the acidic alkyl alkylphosphonic acids (AAPAs) and alkylphosphonic acids (APAs). Quantitative measurements of analytes were performed in the selected ion monitoring mode of GC-MS. Full scan mode of analysis was followed for identifications. Under the optimized conditions analytes were recovered in the range of 39.7-98.8% (n=3, relative standard deviations (RSD) from 0.3 to 6.5%). Limits of detection (LODs) were in the range of 0.1-1.1ngmL(-1); and the linear dynamic range was 5-1000ngmL(-1) with r(2) of 0.9977-0.9769. Applicability of the method was tested with rain-, tap-, muddy-water and Organization for Prohibition of Chemical Weapons (OPCW) Proficiency Test samples. PMID:25863924

  9. A high-throughput 2D-analytical technique to obtain single protein parameters from complex cell lysates for in silico process development of ion exchange chromatography.

    Science.gov (United States)

    Kröner, Frieder; Elsäßer, Dennis; Hubbuch, Jürgen

    2013-11-29

    The accelerating growth of the market for biopharmaceutical proteins, the market entry of biosimilars and the growing interest in new, more complex molecules constantly pose new challenges for bioseparation process development. In the presented work we demonstrate the application of a multidimensional, analytical separation approach to obtain the relevant physicochemical parameters of single proteins in a complex mixture for in silico chromatographic process development. A complete cell lysate containing a low titre target protein was first fractionated by multiple linear salt gradient anion exchange chromatography (AEC) with varying gradient length. The collected fractions were subsequently analysed by high-throughput capillary gel electrophoresis (HT-CGE) after being desalted and concentrated. From the obtained data of the 2D-separation the retention-volumes and the concentration of the single proteins were determined. The retention-volumes of the single proteins were used to calculate the related steric-mass action model parameters. In a final evaluation experiment the received parameters were successfully applied to predict the retention behaviour of the single proteins in salt gradient AEC. PMID:24139506

  10. Molecular rheology of branched polymers: Decoding and exploring the role of architectural dispersity through a synergy of anionic synthesis, interaction chromatography, rheometry and modeling

    KAUST Repository

    Van Ruymbeke, Evelyne

    2014-01-01

    An emerging challenge in polymer physics is the quantitative understanding of the influence of a macromolecular architecture (i.e., branching) on the rheological response of entangled complex polymers. Recent investigations of the rheology of well-defined architecturally complex polymers have determined the composition in the molecular structure and identified the role of side-products in the measured samples. The combination of different characterization techniques, experimental and/or theoretical, represents the current state-of-the-art. Here we review this interdisciplinary approach to molecular rheology of complex polymers, and show the importance of confronting these different tools for ensuring an accurate characterization of a given polymeric sample. We use statistical tools in order to relate the information available from the synthesis protocols of a sample and its experimental molar mass distribution (typically obtained from size exclusion chromatography), and hence obtain precise information about its structural composition, i.e. enhance the existing sensitivity limit. We critically discuss the use of linear rheology as a reliable quantitative characterization tool, along with the recently developed temperature gradient interaction chromatography. The latter, which has emerged as an indispensable characterization tool for branched architectures, offers unprecedented sensitivity in detecting the presence of different molecular structures in a sample. Combining these techniques is imperative in order to quantify the molecular composition of a polymer and its consequences on the macroscopic properties. We validate this approach by means of a new model asymmetric comb polymer which was synthesized anionically. It was thoroughly characterized and its rheology was carefully analyzed. The main result is that the rheological signal reveals fine molecular details, which must be taken into account to fully elucidate the viscoelastic response of entangled branched

  11. Radiochemical neutron activation analysis of high pure palladium and platinum by ion exchange chromatography

    International Nuclear Information System (INIS)

    Full text: The palladium and platinum are widely used for jewel manufacture because of their beautiful white color. However the most part of these metals are widely adopted in the world as catalysts. Many works on analytical chemistry of platinum group elements published during last years are devoted to determination of platinum and palladium in other materials. There are no articles on analysis technique of the palladium and platinum purity published during last 20 years. Available publications are very old and are published till 70th of the last century, and implement chemical and spectral methods. At the same time, the palladium and platinum are very suitable for NAA. Therefore the purpose of our research was development of high-sensitivity and multielement techniques of radiochemical neutron activation analysis of a high pure palladium and platinum. Research of nuclear characteristics of palladium and platinum has shown that radioactive nuclides with different yields are formed under the reactor neutrons. 109, 111, 111mPd, 109m, 111Ag, 191,197, 199Pt, 199Au are the most important among them. 109Pd separation factor is equal to 1*105 at palladium analysis, whereas 197Pt and 199Au separation factor is equal to 1*104 at the platinum analysis every other day after irradiation. Palladium and platinum can be separated by precipitation, extraction and ion exchange methods. For separation of radioactive nuclide of the matrix elements from the impurity elements we used ion exchange chromatography system Dowex-1x8 - 1 M HNO3 for palladium and Dowex-1x8 - 0.1 M HNO3 for platinum. At the HNO3 acid concentrations variation from 0,1 M to 1 M more then 25 elements have distribution factors less than 1 and 10 elements have distribution factors 5 while matrix elements have distribution factors higher than 100. It allows an effective separation of these elements from palladium and platinum. Optimum sizes of the chromatographic column and the column effluent volume was obtained

  12. Band 3, the human red cell chloride/bicarbonate anion exchanger (AE1, SLC4A1), in a structural context.

    Science.gov (United States)

    Reithmeier, Reinhart A F; Casey, Joseph R; Kalli, Antreas C; Sansom, Mark S P; Alguel, Yilmaz; Iwata, So

    2016-07-01

    The crystal structure of the dimeric membrane domain of human Band 3(1), the red cell chloride/bicarbonate anion exchanger 1 (AE1, SLC4A1), provides a structural context for over four decades of studies into this historic and important membrane glycoprotein. In this review, we highlight the key structural features responsible for anion binding and translocation and have integrated the following topological markers within the Band 3 structure: blood group antigens, N-glycosylation site, protease cleavage sites, inhibitor and chemical labeling sites, and the results of scanning cysteine and N-glycosylation mutagenesis. Locations of mutations linked to human disease, including those responsible for Southeast Asian ovalocytosis, hereditary stomatocytosis, hereditary spherocytosis, and distal renal tubular acidosis, provide molecular insights into their effect on Band 3 folding. Finally, molecular dynamics simulations of phosphatidylcholine self-assembled around Band 3 provide a view of this membrane protein within a lipid bilayer. PMID:27058983

  13. Rapid chiral separation and impurity determination of levofloxacin by ligand-exchange chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Hongyuan [Center for Advanced Bioseparation Technology, Department of Chemical Engineering, Inha University, Incheon 402-751 (Korea, Republic of); Row, Kyung Ho [Center for Advanced Bioseparation Technology, Department of Chemical Engineering, Inha University, Incheon 402-751 (Korea, Republic of)]. E-mail: rowkho@inha.ac.kr

    2007-02-12

    A sensitive, simple, and accurate method for determination of levofloxacin and its (R)-enantiomer was developed to determine the chiral impurity of levofloxacin in Cravit Tablets material by ligand-exchange high performance liquid chromatography. The effects of different kinds of ligands, concentration of ligands in mobile phase, organic modifier, pH of mobile phase, and temperature on enantioseparation were investigated and evaluated. Chiral separation was performed on a conventional C{sub 18} column, where the mobile phase consisted of a methanol-water solution (containing10 mmol L{sup -1} L-leucine and 5 mmol L{sup -1} copper sulfate) (88:12, v/v) and its flow-rate was set at 1.0 mL min{sup -1}. The conventional C{sub 18} column offers baseline separation of two enantiomers with a resolution of 2.4 in less than 20 min. Thermodynamic data ({delta}{delta}H and {delta}{delta}S) obtained by Van't Hoff plots revealed the chiral separation is an enthalpy-controlled process. The standard curves showed excellent linearity over the concentration range from 0.5 to 400 mg L{sup -1} for levofloxacin and its (R)-enantiomer. The linear correlation equations are: y = 1.33 x 10{sup 5} x + 6297 (r = 0.9991) and y = 1.34 x 10{sup 5} x + 3565 (r = 0.9997), respectively. The relative standard deviation (RSD) of the method was below 2.3% (n = 3)

  14. Separation of proteins by cation-exchange sequential injection chromatography using a polymeric monolithic column.

    Science.gov (United States)

    Masini, Jorge Cesar

    2016-02-01

    Since sequential injection chromatography (SIC) emerged in 2003, it has been used for separation of small molecules in diverse samples, but separations of high molar mass compounds such as proteins have not yet been described. In the present work a poly(glycidyl methacrylate-co-ethylene dimethacrylate) (GMA-co-EDMA) monolithic column was prepared by free radical polymerization inside a 2.1-mm-i.d. activated fused silica-lined stainless steel tubing and modified with iminodiacetic acid (IDA). The column was prepared from a mixture of 24% GMA, 16% EDMA, 20% cyclohexanol, and 40% 1-dodecanol (all% as w/w) containing 1% of azobisisobutyronitrile (AIBN) (in relation to monomers). Polymerization was done at 60 °C for 24 h. The polymer was modified with 1.0 M IDA (in 2 M Na2CO3, pH 10.5) at 80 °C for 16 h. Separation of myoglobin, ribonuclease A, cytochrome C, and lysozyme was achieved at pH 7.0 (20 mM KH2PO4/K2HPO4) using a salt gradient (NaCl). Myoglobin was not retained, and the other proteins were separated by a gradient of NaCl created inside the holding coil (4 m of 0.8-mm-i.d. PTFE tubing) by sequential aspiration of 750 and 700 μL of 0.2 and 0.1 M NaCl, respectively. As the flow was reversed toward the column (5 μL s(-1)) the interdispersion of these solutions created a reproducible gradient which separated the proteins in 10 min, with the following order of retention: ribonuclease A < cytochrome C < lysozyme. The elution order was consistent with a cation-exchange mechanism as the retention increased with the isoelectric points. PMID:26677024

  15. Long-term performance of bicarbonate-form anion exchange: removal of dissolved organic matter and bromide from the St. Johns River, FL, USA.

    Science.gov (United States)

    Walker, Krystal M; Boyer, Treavor H

    2011-04-01

    The goal of this research was to evaluate the long-term performance of magnetic ion exchange (MIEX) treatment using bicarbonate as the mobile counter ion (i.e., MIEX-HCO(3)) and sodium bicarbonate for regeneration. This work is important because there are many unknowns concerning the affinity and regeneration efficiency of bicarbonate-form anion exchange, whereas chloride-form anion exchange (i.e., MIEX-Cl resin) is well-studied. Raw water samples were collected approximately two times per month for one year from a single location on the St. Johns River (SJR), FL, USA. The SJR is characterized by high concentrations of dissolved organic carbon (DOC; 12-26 mg C/L) and bromide (550-1100 μg/L), and is being considered as an alternative drinking water supply. Jar tests were conducted using MIEX-HCO(3) resin, and MIEX-Cl resin was used as a baseline for comparison. The same batch of MIEX-HCO(3) and MIEX-Cl resin was used for the entire study, which was accomplished by regenerating the resins after each jar test in concentrated solutions of sodium bicarbonate and sodium chloride, respectively, and resulted in 21 regeneration cycles. Maximum removal efficiency was achieved with fresh MIEX-HCO(3) resin and virgin MIEX-Cl resin. Both forms of fresh/virgin MIEX resin also had the same affinity sequence with sulfate ≈ UV-absorbing substance > DOC > bromide. The removal efficiency of both forms of MIEX resin decreased as the number of regeneration cycles increased, with MIEX-HCO(3) resin showing 7-18% lower removals than MIEX-Cl resin after 21 regeneration cycles. The affinity sequence of regenerated MIEX-HCO(3) and MIEX-Cl resins differed from fresh resin with UV-absorbing substances > DOC > sulfate > bromide. Scanning electron microscopy and simulated MIEX-HCO(3) treatment under rapidly changing water quality were also used to improve the understanding of bicarbonate-form anion exchange. The major contribution of this research is a systematic study of the extended use of

  16. tRNA separation by high-performance liquid chromatography using an aggregate of ODS-Hypersil and trioctylmethylammonium chloride

    NARCIS (Netherlands)

    Bischoff, Rainer; Graeser, E.; Mclaughlin, L.W.

    1983-01-01

    High-performance liquid chromatography on a reversed-phase support treated with a tetraalkylammonium salt was used to separate tRNAs from baker's yeast. While resolution by this column appears to result from both anion-exchange and reversed-phase chromatography, it is the hydrophobic interactions wh

  17. A Multidimensional System for Phosphopeptide Analysis Using TiO2 Enrichment and Ion-exchange Chromatography with Mass Spectrometry

    International Nuclear Information System (INIS)

    Although offline enrichment of phosphorylated peptides is widely used, enrichment for phosphopeptides using TiO2 is often performed manually, which is labor-intensive and can lead to irreproducible results. To address the problems associated with offline enrichment and to improve the effectiveness of phosphopeptide detection, we developed an automated online enrichment system for phosphopeptide analysis. A standard protein mixture comprising BSA, fetuin, crystalline, α-casein and β-casein, and ovalbumin was assessed using our new system. Our multidimensional system has four main parts: a sample pump, a 20-mm TiO2-based column, a weak anion-exchange, and a strong cation-exchange (2:1 WAX:SCX) separation column with LC/MS. Phosphorylated peptides were successfully detected using the TiO2-based online system with little interference from nonphosphorylated peptides. Our results confirmed that our online enrichment system is a simple and efficient method for detecting phosphorylated peptides

  18. Separation of rare earths from uranium by anion exchange with pre-exclusion of loading solution under pressure and determination by ICP-MS

    International Nuclear Information System (INIS)

    An intermittently pressurized anion exchange column is used for separation of trace rare earth elements (REES) from uranium before ICP-MS measurements. The whole separation can be completed within 20 min. The recoveries for all REES are in the range of 96%-106%. Comparing with previous methods, this technique consumes less chemicals and produces less waste. The applicability and reliability of this procedure is demonstrated by the good accordance between results determined by this method and the recommended values for REES in a standard reference material (GBW04207). It is proved that this method would be useful for analysis of trace REES impurities in uranium metal and its oxides

  19. Complexation of uranyl ions. III. Investigation of the sorption of uranium of the VP-1Ap anion exchanger from carbonate media by x-ray spectrometric microanalysis

    International Nuclear Information System (INIS)

    The spatial distribution of uranium in granules of the VP-1Ap anion exchanger during heightened sorption from carbonate media has been investigated by x-ray spectroscopic microanalysis. Variation of the form of the concentration profile as a function of the extent of sorption from a uniform profile across the diameter, then to a meniscus-shaped profile, and finally to a smoothed profile with an increase in the coefficient of nonuniformity of the distribution of uranium in the granules from 0.026 to 0.045 has been established

  20. Study on the identification of organic and common anions in the pyrohydrolysis distillate of mixed uranium-plutonium carbide for the interference free determination of chlorine and fluorine by ion chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Jeyakumar, Subbiah; Mishra, Vivekchandra Guruprasad; Das, Mrinal Kanti; Raut, Vaibhavi Vishwajeet; Sawant, Ramesh Mahadeo [Bhabha Atomic Research Centre, Mumbai (India). Radioanalytical Chemistry Div.; Ramakumar, Karanam Lakshminarayana [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry and Isotope Group

    2014-07-01

    Identification of various soluble organic acids formed during the pyrohydrolysis of uranium-plutonium mixed carbide [(U,Pu)C] was carried out using ion chromatography. This has significant importance as the soluble organic acids can cause severe interferences during the ion chromatography separation and determination of Cl{sup -} and F{sup -} in the pyrohydrolysis distillate of (U,Pu)C. Determination of Cl and F is important in the chemical quality control of nuclear materials as these two elements can cause corrosion and hence, their concentrations in all nuclear materials are restricted to certain specified values. Since the pyrohydrolysis distillates contain both inorganic and organic acid anions, for the sake of separating and identifying organic acid anions from the common inorganic anions, three independent isocratic elutions using varying concentrations of NaOH eluent were employed for the separation of weakly, moderately and strongly retained anions. It was observed that pyrohydrolysis of (U,Pu)C also produced soluble organic acids as in the case of nitric acid dissolution of UC. The present investigation revealed the presence of formic, acetic, propionic, butyric, oxalic acid anions in the pyrohydrolysis distillate of (U,Pu)C in trace or ultra-trace concentrations. The presence of each organic acid identified in the chromatogram was confirmed with spike addition as well as by separating them by capillary electrophoresis method. The presence of lower aliphatic acids viz. formic and acetic acids was reconfirmed by carrying out an independent separation with tetraborate eluent. It is suggested that nitric acid being formed during pyrohydrolysis could be responsible for the formation of organic acids. Based on the findings, an ion chromatography separation method has been proposed for the interference-free determination of chloride and fluoride in pyrohydrolysis distillate of (U,Pu)C. (orig.)

  1. Study on the identification of organic and common anions in the pyrohydrolysis distillate of mixed uranium-plutonium carbide for the interference free determination of chlorine and fluorine by ion chromatography

    International Nuclear Information System (INIS)

    Identification of various soluble organic acids formed during the pyrohydrolysis of uranium-plutonium mixed carbide [(U,Pu)C] was carried out using ion chromatography. This has significant importance as the soluble organic acids can cause severe interferences during the ion chromatography separation and determination of Cl- and F- in the pyrohydrolysis distillate of (U,Pu)C. Determination of Cl and F is important in the chemical quality control of nuclear materials as these two elements can cause corrosion and hence, their concentrations in all nuclear materials are restricted to certain specified values. Since the pyrohydrolysis distillates contain both inorganic and organic acid anions, for the sake of separating and identifying organic acid anions from the common inorganic anions, three independent isocratic elutions using varying concentrations of NaOH eluent were employed for the separation of weakly, moderately and strongly retained anions. It was observed that pyrohydrolysis of (U,Pu)C also produced soluble organic acids as in the case of nitric acid dissolution of UC. The present investigation revealed the presence of formic, acetic, propionic, butyric, oxalic acid anions in the pyrohydrolysis distillate of (U,Pu)C in trace or ultra-trace concentrations. The presence of each organic acid identified in the chromatogram was confirmed with spike addition as well as by separating them by capillary electrophoresis method. The presence of lower aliphatic acids viz. formic and acetic acids was reconfirmed by carrying out an independent separation with tetraborate eluent. It is suggested that nitric acid being formed during pyrohydrolysis could be responsible for the formation of organic acids. Based on the findings, an ion chromatography separation method has been proposed for the interference-free determination of chloride and fluoride in pyrohydrolysis distillate of (U,Pu)C. (orig.)

  2. Development of the ERIX process for reprocessing spent FBR-MOX fuel. Electrolytic reduction and anion exchange separation for U and FPs containing solution

    International Nuclear Information System (INIS)

    In recent years, we have been investigating the development of the ERIX process for reprocessing spent FBR-MOX fuel. The ERIX process uses electrolytic reduction and ion exchange techniques to recover U, Pu, Np and the minor actinides from spent EBR-MOX fuel solution. In previous work, it was found that U(VI) can be effectively reduced to U(IV) using the flow type electrolytic cell and U(IV) can be completely separated from fission products by AR-01 anion exchanger packed column in nitric acid medium. In the present work, electrolytic reduction behaviors of U(VI) and FPs containing solutions were investigated and the effects of various fission products, hydrazine, nitric acid and nitrous acid were examined. Furthermore, separation behavior of U from typical fission products in 6 mol/dm3 nitric acid solution after the electrolytic reduction were investigated using the column packed with AR-01. (author)

  3. Performance evaluation of anion exchange resins Purolite NRW-5050 and Duolite A-611 by application of radioisotopic techniques

    International Nuclear Information System (INIS)

    Radioanalytical techniques using 131I and 82Br as tracer isotopes were applied to study the kinetics of iodide and bromide ion-isotopic exchange reactions taking place between the external labeled ionic solution and the resin surface. The results indicate low values of specific reaction rate (min-1), amount of ion exchanged (mmol) and initial rate of ion exchange (mmol/min) for bromide ion-isotopic exchange reaction as compared to that obtained for iodide ion-isotopic exchange reaction. It was observed that for iodide ion-isotopic exchange reaction performed at 35.0 C, 1 000 g of ion exchange resins and 0.002 mol/L labeled iodide ion solution, the values of specific reaction rate (min-1), amount of iodide ion exchanged (mmol), initial rate of iodide ion exchange (mmol/min) and log Kd were 0.340, 0.394, 0.134 and 20.2 respectively for Purolite NRW-5050 resin, which was higher than the respective values of 0.216, 0.290, 0.063 and 18.2 as that obtained by using Duolite A-611. The results of present investigation indicate that during the two ion-isotopic exchange reactions, for both the resins, there exists a strong positive linear correlation between amount of ions exchanged and concentration of ionic solution; and strong negative correlation between amount of ions exchanged and temperature of exchanging medium. From the results it appears that as compared to Duolite A-611 resins, Purolite NRW-5050 resins shows superior performance under identical experimental conditions.

  4. Speciation of eight arsenic compounds in human urine by high performance liquid chromatography with inductively coupled plasma mass spectrometric detection using antimonate for internal chromatographic standardization

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Pritzl, G.; Hansen, S. H.

    1993-01-01

    Four anionic and four cationic arsenic compounds in urine were separated by anion- and cation-exchange high-performance liquid chromatography and detected by inductively coupled plasma mass spectrometry (ICP-MS) at m/z 75. The species were the anions arsenite, arsenate, monomethylarsonate and...... arsenate in urine but was stable after at least 4-fold dilution of the urine with water. Arsenite was unstable in both urine samples and standard mixtures when diluted with the basic (pH 10.3) mobile phase used for anion chromatography. This could not be prevented by adding ascorbic acid as antioxidant...

  5. Ion distribution in quaternary-ammonium-functionalized aromatic polymers: effects on the ionic clustering and conductivity of anion-exchange membranes.

    Science.gov (United States)

    Weiber, E Annika; Jannasch, Patric

    2014-09-01

    A series of copoly(arylene ether sulfone)s that have precisely two, three, or four quaternary ammonium (QA) groups clustered directly on single phenylene rings along the backbone are studied as anion-exchange membranes. The copolymers are synthesized by condensation polymerizations that involve either di-, tri-, or tetramethylhydroquinone followed by virtually complete benzylic bromination using N-bromosuccinimide and quaternization with trimethylamine. This synthetic strategy allows excellent control and systematic variation of the local density and distribution of QA groups along the backbone. Small-angle X-ray scattering of these copolymers shows extensive ionic clustering, promoted by an increasing density of QA on the single phenylene rings. At an ion-exchange capacity (IEC) of 2.1 meq g(-1), the water uptake decreases with the increasing local density of QA groups. Moreover, at moderate IECs at 20 °C, the Br(-) conductivity of the densely functionalized copolymers is higher than a corresponding randomly functionalized polymer, despite the significantly higher water uptake of the latter. Thus, the location of multiple cations on single aromatic rings in the polymers facilitates the formation of a distinct percolating hydrophilic phase domain with a high ionic concentration to promote efficient anion transport, despite probable limitations by reduced ion dissociation. These findings imply a viable strategy to improve the performance of alkaline membrane fuel cells. PMID:25044778

  6. Determination of uranium isotopes in urine samples from radiation workers using 232U tracer, anion-exchange resin and alpha-spectrometry

    International Nuclear Information System (INIS)

    Bioassay technique is used for the estimation of actinides present in the body based on the excretion rate of body fluids. For occupational radiation workers urine assay is the preferred method for monitoring of chronic internal exposure. Determination of low concentrations of actinides such as plutonium, americium and uranium at low level of mBq in urine by alpha-spectrometry requires pre-concentration of large volumes of urine. This paper deals with standardization of analytical method for the determination of U-isotopes in urine samples using anion-exchange resin and 232U tracer for radiochemical recovery. The method involves oxidation of urine followed by co-precipitation of uranium along with calcium phosphate. Separation of U was carried out by Amberlite, IRA-400, anion-exchange resin. U-fraction was electrodeposited and activity estimated using tracer recovery by alpha-spectrometer. Eight routine urine samples of radiation workers were analyzed and consistent radiochemical tracer recovery was obtained in the range of 51% to 67% with a mean and standard deviation of 60% and 5.4%, respectively. (author)

  7. Feasibility of wavelength dispersive X-ray fluorescence spectrometry for a simplified analysis of bromine in water samples with the aid of a strong anion exchange disk

    International Nuclear Information System (INIS)

    The feasibility of wavelength dispersive X-ray fluorescence spectrometry (WDXRF) for a simplified analysis of bromine (Br) in water samples with the aid of strong anion exchange (SAX) disk was assessed in this study. Dissolved Br in the water sample was pre-concentrated on the SAX disk and directly analyzed by WDXRF without an elution step. The SAX disk was capable of fully adsorbing both bromide (Br−) and bromate (BrO3−) on its surface owing to their anionic properties, regardless of the pH level of environmental samples. The SAX–WDXRF system was examined using calibration standards (i.e., SAX disks with specific amounts of Br retained; 1, 10, 50, 100 and 500 μg), and a determination coefficient of R2 = 0.9999 was yielded. The system had a low detection limit for Br (limit of detection = 0.253 μg for Br on the SAX disk) with good reproducibility (relative standard error (RSE) = 4–7%). Spike and inter-comparison tests were performed to confirm the accuracy of the proposed SAX–WDXRF method. Both tests exhibited reasonable accuracy (RSE = 3–6%). The method is simple and easy, indicating a great possibility of application in various environmental sample types, especially for which a simplified analytical system for the determination of Br is urgently required. - Highlights: • Bromide and bromate were entirely retained on a strong anion exchange (SAX) disk. • The SAX disk was used to pre-concentrate dissolved Br species from water samples. • The SAX disk adsorbing dissolved Br was directly analyzed by WDXRF. • The accuracy of the SAX–WDXRF method was confirmed by spike and inter-comparison tests. • Rapid and sensitive Br analysis can be achieved using the proposed SAX–WDXRF method

  8. Air quality status in Kinshasa as determined by instrumental neutron activation analysis, atomic absorption spectrometry and ion-exchange chromatography

    International Nuclear Information System (INIS)

    Three independent analytical techniques - instrumental neutron activation analysis. Atomic absorption spectrometry and ion-exchange chromatography - were applied to airborne particulate collected on filters and to atmospheric acid gases collected in carbonate buffer solutions. 20 trace elements and 7 acid gases and acid aerosols were determined. Results were compared with those observed elsewhere and showed that air pollution is low in Kinshasa and does not give rise to anxieties. The main known sources of pollutants are: vehicle exhaust and aeolian process on stripped soils. (author). 13 refs, 2 figs, 6 tabs

  9. Quality of 2-deoxy-2-[18F]fluoro-d-glucose injection prepared by isotopic exchange of fluorine using anion exchange or liquid phase exchange catalysed with amino polyether

    International Nuclear Information System (INIS)

    Production of 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) for Czech and Slovak PET Centres started on our upgraded U-120 cyclotron and in our radiopharmaceutical laboratory as early as June 1997, first for validation purposes and subsequently for clinical trials. The product was registered by the Czech State Institute for Drug Control in June 1999, and then distribution of the [18F]FDG injection preparation to hospitals was launched. The older automatic equipment (MicroLab I) manufactured by General Electric Medical Systems (GEMS) was based on a technology involving nucleophilic substitution of the precursor (1,3,4,6-tetra-O-acetyl-2-O-trifluoromethanesulfonyl-β-D-mannopyranose) dissolved in acetonitrile with [18F]fluoride absorbed on a solid anion exchanger modified with 4-(4-methylpiperidino) pyridine. This technology was used by us until March 2001, when it was superseded by a more advanced technology, MicroLab II. The nucleophilic substitution in the new technology is catalysed with amino polyether (Kryptofix) in a liquid phase. Benefits of MicroLab II include a significantly higher yield and better radiochemical purity of the product

  10. Quality of 2-deoxy-2-[18 F]fluoro-D-glucose injection prepared by isotopic exchange of fluorine using anion exchange or liquid phase exchange catalysed with aminopolyether

    International Nuclear Information System (INIS)

    Regular production of 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) for Czech and Slovak PET Centers started at our upgraded U-120 cyclotrone and radiopharmaceutical laboratory already in June 1997 when [18F]FDG started being produced for validation and then for clinical trials in the Czech Republic. After registering the product by the Czech State Institute for Drug Control in June 1999, distribution of [18F]FDG,injection, to hospitals was commenced. The older automatic equipment (MicroLab I) of General Electric Medical Systems (GEMS) used technology with nucleophilic substitution of precursor (1,3,4,6-tetra-O-acetyl-2-O-trifluormethansulfonyl-β-D-mannopyranose) dissolved in acetonitrile with [18F]fluoride absorbed on a solid anion exchanger modified with 4-(4-methylpiperidino) pyridine. We used this technology until March 2001, when it was substituted with more advanced technology, MicroLab II. Nucleophilic substitution in the new technology is catalysed with aminopolyether (Kryptofix) in a liquid phase. Benefits of the MicroLab II technology consist of significantly higher yield of synthesis and better radiochemical purity of the product. Those parameters for intermediate period in March 2001 when both technologies were used is presented, so the conditions for production were comparable. The MicroLab II technology brings much higher yield of synthesis while radiochemical purity of the product also increases to over 99%

  11. Extraction of Tetra-oxo Anions into a Hydrophobic, Ionic Liquid-Based Solvent Without Concomitant Ion Exchange

    International Nuclear Information System (INIS)

    Hydrophobic ionic liquids (IL) have the potential to simplify certain separations by serving as both an extraction solvent and an electrolyte for subsequent electrochemical reductions. While IL-based solvents are known to be efficient media for metal ion extraction, separations employing these solvents are frequently complicated by the loss of constituent IL ions to the aqueous phase, resulting in deteriorating performance. In this study, we have examined the extraction of pertechnetate and related tetra-oxo anions from aqueous solutions into IL-based solvents incorporating tetraalkylphosphonium bis((trifluoromethyl)sulfonyl)imide and a crown ether. In contrast to various previously studied IL-based cation extraction systems, facile anion extraction without significant transfer of the IL ions to the aqueous phase has been observed. In addition, the solvents exhibit high distribution ratios (100-500 for pertechnetate), significant electrical conductivity (>100 (micro)S/cm), and a wide (∼4 V) electrochemical window. The results suggest that these solvents may provide the basis for improved approaches to the extraction and recovery of a variety of anions.

  12. Synthesis and anion exchange reactions of a layered copper-zinc hydroxy double salt, Cu1×6Zn0×4(OH)3(OAc)×H2O

    Indian Academy of Sciences (India)

    Jacqueline Therese Rajamathi; Sylvia Britto; Michael Rajamathi

    2005-11-01

    A mixed-metal hydroxysalt of formula Cu1.6Zn0.4(OH)3(OAc)$\\cdot$H2O has been synthesized by an acetate hydrolysis route. Acetate ions can be exchanged with simple inorganic anions such as chloride and nitrate, and organic anions such as benzoate and large surfactant anions such as dodecyl sulphate. Structures of these hydroxysalts are derived from that of Cu2(OH)3NO3$\\cdot$H2O with some of the Cu2+ ions being replaced by Zn2+.

  13. R and D studies at IGCAR on boron enrichment using ion exchange chromatography process. Contributed Paper IT-10

    International Nuclear Information System (INIS)

    Boron Carbide enriched in 10B isotope is used as control rod material for fast reactors. The natural abundance of 10B isotope of boron is about 20%. In addition to the use in control rods for fast reactors, enriched boron compounds find many other applications in nuclear industry such as in neutron detection, shielding and burnable poison in moderators of thermal reactors and also in neutron capture therapy. To meet the growing demand for 10B enriched materials, it has become necessary to develop efficient processes to enrich this isotope of boron. Among the known processes, ion exchange chromatography is a viable option for the industrial enrichment of this isotope of boron. Pilot scale experiments were carried out to study the band velocity, influence of complexing agent, variation of HETP with time, influence of initial eed enrichment and particle size of the resin. A Model for ion exchange chromatography was developed and validated to predict HETP for different operating conditions. This model is effective in analysing plant operation and also design of new boron enrichment plants

  14. Ion-exchange solid-phase extraction combined with liquid chromatography-tandem mass spectrometry for the determination of veterinary drugs in organic fertilizers.

    Science.gov (United States)

    Zhao, Zhiyong; Zhang, Yanmei; Xuan, Yanfang; Song, Wei; Si, Wenshuai; Zhao, Zhihui; Rao, Qinxiong

    2016-06-01

    The analysis of veterinary drugs in organic fertilizers is crucial for an assessment of potential risks to soil microbial communities and human health. We develop a robust and sensitive method to quantitatively determine 19 veterinary drugs (amantadine, sulfonamides and fluoroquinolones) in organic fertilizers. The method involved a simple solid-liquid extraction step using the combination of acetonitrile and McIlvaine buffer as extraction solvent, followed by cleanup with a solid-phase extraction cartridge containing polymeric mixed-mode anion-exchange sorbents. Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to separate and detect target analytes. We particularly focused on the optimization of sample clean-up step: different diluents and dilution factors were tested. The developed method was validated in terms of linearity, recovery, precision, sensitivity and specificity. The recoveries of all the drugs ranged from 70.9% to 112.7% at three concentration levels, with the intra-day and inter-day relative standard deviation lower than 15.7%. The limits of quantification were between 1.0 and 10.0μg/kg for all the drugs. Matrix effect was minimized by matrix-matched calibration curves. The analytical method was successfully applied for the survey of veterinary drugs contamination in 20 compost samples. The results indicated that fluoroquinolones had higher incidence rate and mean concentration levels ranging from 31.9 to 308.7μg/kg compared with other drugs. We expect the method will provide the basis for risk assessment of veterinary drugs in organic fertilizers. PMID:27131104

  15. Borate fusion followed by ion-exchange/extraction chromatography for the rapid determination of Pu and U in environmental materials

    International Nuclear Information System (INIS)

    A method for actinide determinations has been established which has considerable advantages over currently described procedures. The benefits are rapid sample throughput, good safety features with no compromise in data quality. A borate fusion is used for the sample digestion. Chemical separation is optimized by using a column of anion-exchange resin column stacked on a UTEVA column. Uranium was measured using thermal ionization mass spectrometry with a precision of 0.2% 2 sigma. Pu measurements were made using alpha-particle spectrometry. The procedure has been applied successfully to a wide range of sample types and other actinide elements (Th, Am, etc.) could also be included in the analytical scheme. The method has been thoroughly evaluated by measuring international reference samples. The method lends itself very well to large-scale environmental surveys

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-01

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

  17. Fixation and separation of the elements thorium and uranium using anion exchange resins in nitrate solution; Fixation et separation des elements thorium et uranium par les resines echangeuses d'anions en milieu nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Korgaonkar, V. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1967-10-01

    The exchange of thorium and uranium between a strong base anion resin and a mixed water + ethanol solvent containing nitrate ions is studied. It is assumed that in the resin the thorium and uranium are fixed in the form of the complexes Th(NO{sub 3}){sub 6}{sup 2-} and UO{sub 2}(NO{sub 3}){sub 4}{sup 2-} in solution these elements are present in the form of complexes having the general formula: Th(NO{sub 3}){sub 6-n}{sup n-2} and UO{sub 2}(NO{sub 3}){sub 4-n}{sup n-2} It has been possible to deduce a law for the changes in the partition functions of thorium and uranium as a function of the concentrations of the various species in solution and of the complexing ion NO{sub 3}. From this has been deduced the optimum operational conditions for separating a mixture of these two elements. Finally, in these conditions, the influence of a few interfering ions has been studied: Ba, Bi, Ce, La, Mo, Pb, Zr. The method proposed can be used either as a preparation, or for the dosage of thorium by a quantitative separation. (author) [French] On etudie l'echange du thorium et de l'uranium entre une resine anion base forte et un solvant mixte eau + ethanol charge en ions nitrates. On a suppose que, dans la resine, le thorium et l'uranium sont fixes sous forme de complexes Th(NO{sub 3}){sub 6}{sup 2-} et UO{sub 2}(NO{sub 3}){sub 4}{sup 2-} en solution, ces elements sont engages dans des complexes de formule generale: Th(NO{sub 3}){sub 6-n}{sup n-2} and UO{sub 2}(NO{sub 3}){sub 4-n}{sup n-2} On a pu degager une loi de variation des coefficients de partage du thorium et de l'uranium en fonction des concentrations des diverses especes en solution et de l'anion complexant NO{sub 3}{sup -}. On en a deduit les conditions operatoires optimales necessaires pour separer les deux elements a partir de leurs melanges. Enfin, dans ces conditions, on a etudie l'influence de quelques elements genants: Ba, Bi, Ce, La, Mo, Pb, Zr. La methode preconisee peut etre

  18. LAB-SCALE DEMONSTRATION OF PLUTONIUM PURIFICATION BY ANION EXCHANGE, PLUTONIUM (IV) OXALATE PRECIPITATION, AND CALCINATION TO PLUTONIUM OXIDE TO SUPPORT THE MOX FEED MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Crowder, M.; Pierce, R.

    2012-08-22

    H-Canyon and HB-Line are tasked with the production of PuO{sub 2} from a feed of plutonium metal. The PuO{sub 2} will provide feed material for the MOX Fuel Fabrication Facility. After dissolution of the Pu metal in H-Canyon, the solution will be transferred to HB-Line for purification by anion exchange. Subsequent unit operations include Pu(IV) oxalate precipitation, filtration and calcination to form PuO{sub 2}. This report details the results from SRNL anion exchange, precipitation, filtration, calcination, and characterization tests, as requested by HB-Line1 and described in the task plan. This study involved an 80-g batch of Pu and employed test conditions prototypical of HB-Line conditions, wherever feasible. In addition, this study integrated lessons learned from earlier anion exchange and precipitation and calcination studies. H-Area Engineering selected direct strike Pu(IV) oxalate precipitation to produce a more dense PuO{sub 2} product than expected from Pu(III) oxalate precipitation. One benefit of the Pu(IV) approach is that it eliminates the need for reduction by ascorbic acid. The proposed HB-Line precipitation process involves a digestion time of 5 minutes after the time (44 min) required for oxalic acid addition. These were the conditions during HB-line production of neptunium oxide (NpO{sub 2}). In addition, a series of small Pu(IV) oxalate precipitation tests with different digestion times were conducted to better understand the effect of digestion time on particle size, filtration efficiency and other factors. To test the recommended process conditions, researchers performed two nearly-identical larger-scale precipitation and calcination tests. The calcined batches of PuO{sub 2} were characterized for density, specific surface area (SSA), particle size, moisture content, and impurities. Because the 3013 Standard requires that the calcination (or stabilization) process eliminate organics, characterization of PuO{sub 2} batches monitored the

  19. Isolation of radioactive strontium from natural samples. Separation of strontium from alkaline and alkaline earth elements by means of mixed solvent anion exchange

    International Nuclear Information System (INIS)

    This paper presents the results of studies which led to the procedures for the chromatographic separation of radioactive strontium from alkaline, earth-alkaline and other elements in natural samples, on columns filled with strong base anion exchangers using alcoholic solutions of nitric acid as eluents. It has been shown that potassium, caesium, calcium, barium, yttrium and strontium can be adsorbed on strong base anion exchangers of the Dowex and Amberlite type, which contain the quaternary ammonium group with nitrate as counter-ion, from solutions of nitric acid in alcohol. Adsorption strength increases in the order methanol 3 in methanol, while they are adsorbed from ethanol and propanol. The adsorption strength is influenced by the polarity of alcohol, by the concentration of nitrate and by pH. The strength with which strontium adsorbs on the exchangers increases in the interval from 0 to 0.25M NH4NO3 in methanol, after which it starts to decrease. Strontium adsorbs to the exchangers from the alcoholic solution of ammonium nitrate twice as strongly as from the alcoholic solution of nitric acid, while a fraction of water in pure alcohol exceeding 10% prevents adsorption. In the mixture of alcohol and nitric acid, the adsorption strength for calcium and strontium increases with the increase of the volume fraction of alcohol with a lower dielectric constant. The rate and strength of adsorption of ions on the exchanger also increase in the series 0.25M HNO3 in methanol 3 in ethanol 3 in 1-propanol for each individual ion, as well as in the Ca3 in methanol, 0.25M HNO3 in ethanol and 0.25M HNO3 in propanol. Separation is also possible from alcohol mixtures. Strontium separation is most difficult from calcium, while the efficiency of separation increases with a decrease of the polarity of the used alcohol or alcohol mixture. The first group elements of the periodic table are not separated from each other in this way, while the elements of the second group are

  20. Tens of micron-sized unilamellar nanosheets of Y/Eu layered rare-earth hydroxide: efficient exfoliation via fast anion exchange and their self-assembly into oriented oxide film with enhanced photoluminescence

    OpenAIRE

    Qi Zhu; Ji-Guang Li; Xiaodong Li; et al.

    2014-01-01

    Layered rare-earth hydroxide (LRH) crystals of (Y0.95Eu0.05)2(OH)5NO3centerdotnH2O with a lateral size of ~ 300 μm and a thickness of ~ 9 μm have been synthesized via a hydrothermal reaction of mixed nitrate solutions in the presence of mineralizer NH4NO3 at 200 °C for 24 h. LRH exhibits the ability to undergo intercalation and anion exchange with DS− (C12H25OSO3−) via hydrothermal treatment. Compared with traditional anion exchange at room temperature, hydrothermal processing not only shor...

  1. Boron isotopic enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    10B enriched boron is used in applications requiring high volumetric neutron absorption (absorption cross section- 3837 barn for thermal and 1 barn for 1 MeV fast neutron). It is used in fast breeder reactor (as control rod material), in neutron counter, in Boron Neutron Capture Therapy etc. Owing to very small separation factor, boron isotopic enrichment is a complex process requiring large number of separation stages. Heavy Water Board has ventured in industrial scale production of 10B enriched boron using Exchange Distillation Process as well as Ion Displacement Chromatography Process. Ion Displacement Chromatography process is used in Boron Enrichment Plant at HWP, Manuguru. It is based on isotopic exchange between borate ions (B(OH)4-) on anion exchange resin and boric acid passing through resin. The isotopic exchange takes place due to difference in zero point energy of 10B and 11B

  2. Kinetics of fast ligand exchange in excited lanthanide complexes with anions of salicylic and 5-sulfosalisylic acids

    International Nuclear Information System (INIS)

    The luminescent-kinetic spectroscopic method with a flash selective photoexcitation has been used for studying the reaction of ligand substitution with solvent molecules in complexes of electron-excited ions Tb3+(5D4) and Dysup(3+)(sup(4)Fsub(9/2) with anions of salicylic and 5-sulphosalicylic acids in water and methanol. The acidic-catalytic mechanism of this reaction in water has been established, the limiting stage of complex dissociation being the stage of proton addition to the -COO- group of the ligand proceeding at a rate of 1x1010 mol-1s-1 and 0.77x1010 mol-1xs-1 for complexes of Tb3+(5D4) in H2O and D2O. It has been shown that in an aqueous medium anions of salicylic and 5-sulphosalicylic acids behave with respect to r.e.e. ions as bidentate ligands coordinating these ions with the oxygen of the -COO- group and oxygroup whereas in methanol an additional coordination with oxygen of the oxygroup is absent

  3. Sorption behavior of perrhenate ion on ReillexTM-HP anion exchange resin from nitric acid and sodium nitrate/hydroxide solutions

    International Nuclear Information System (INIS)

    The distribution coefficients (K'd) are reported for perrhenate on the nitrate form of ReillexTM-HP, a weak base anion exchange resin, as a function of nitric acid concentration form 0.100 to 10.0 M. Perrhenate K'd values were determined in 1.00 M NaNO3 from pH 2 to 13. The K'd values were determined in solutions containing 1.35 M NaNO3 and variable NaOH, 0.155 to 4.66 M, and in solutions containing 0.655 M NaOH and variable NaNO3, 0.46 to 5.35M. Maximum perrhenate loadings were d is defined by the equation presented here. 30 refs., 4 figs., 1 tab

  4. Optimization of SHINE Process: Design and Verification of Plant-Scale AG 1 Anion-Exchange Concentration Column and Titania Sorbent Pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Stepinski, Dominique C. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Abdul, Momen [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Youker, Amanda J. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Rotsch, David A. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Tkac, Peter [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2016-06-01

    Argonne National Laboratory has developed a Mo-recovery and -purification system for the shine medical technologies process, which uses a uranyl sulfate solution for the accelerator-driven production of Mo-99. The objective of this effort is to reduce the processing time for the acidification of the Mo-99 product prior to loading onto a concentration column and concentration of the Mo-99 product solution. Two methods were investigated: (1) the replacement of the titania concentration column by an anion-exchange column to decrease processing time and increase the radioiodine-decontamination efficiency and (2) pretreatment of the titania sorbent to improve its effectiveness for the Mo-recovery and -concentration columns. Promising results are reported for both methods.

  5. Discovery and early development of non-suppressed ion chromatography.

    Science.gov (United States)

    Fritz, James S; Gjerde, Douglas T

    2010-08-01

    This year marks the 30th anniversary of the publication of Non-Suppressed Ion Chromatography, which is a method for the rapid separation of anions with on-line conductimetric detection. In this method, the separation column is connected directly to the conductimetric detector. This single-column method is a simpler technique than the original suppressed ion chromatography method, which requires a large suppressor column to reduce the background conductance. In the new method, the background signal is reduced to a manageable level simply by using an ion-exchange separation column of low exchange capacity that lowers the eluent concentration needed for separation. The eluent ion used for separation is chosen based on having large, bulky structure, which lowers the equivalent conductance and facilitates detection of the sample anions. This is a personal account of the initial discovery and early development of non-suppressed ion chromatography. The circumstances for the discovery are recounted by the two authors. Methods are described for determination of anions, cations with indirect detection, and techniques for increasing detection sensitivity. A fundamental equation for the prediction of ion chromatography detector response is given, and the development of several types of detection schemes for ion chromatography is discussed. Finally, the impact of non-suppressed ion chromatography is discussed together with comments on the discovery process. PMID:20819275

  6. Purification of Staphylococcus aureus beta-lactamases by using sequential cation-exchange and affinity chromatography.

    OpenAIRE

    Kernodle, D S; Zygmunt, D J; McGraw, P A; Chipley, J R

    1990-01-01

    Boronic acids are active-site inhibitors of serine beta-lactamases, and a phenylboronic acid-agarose affinity column has been used to purify beta-lactamase from crude cell extracts of several bacterial species. We applied phenylboronic acid-agarose chromatography to the purification of Staphylococcus aureus beta-lactamase. Two factors interfered with the success of the previously described single-step chromatographic protocol. First, staphylococcal beta-lactamase exhibited non-active-site-med...

  7. In situ redox speciation analysis of chromium in water by diffusive gradients in thin films using a DE81 anion exchange membrane.

    Science.gov (United States)

    Suárez, Carlos A; de Simone, Thays V; Menegário, Amauri A; Rolisola, Ana M C M; Luko, Karen S; Gastmans, Didier; da Conceição, Fabiano T; Kiang, Chang H

    2016-07-01

    A method for the in situ redox speciation analysis of chromium in water by the diffusive gradients in thin films (DGT) technique using a DE81 anion exchange membrane was successfully developed. For the selective uptake of Cr(VI), a DGT device containing an anion exchange membrane DE81 (cellulose acetate chromatographic paper) was used (DE81-DGT), while selective uptake of Cr(III) was carried out using DGT devices containing the Chelex-100 resin (Chelex-100-DGT). A correlation coefficient of 0.993 was obtained for the linearity of the immersion curves (mass versus time) using DE81-DGT. The diffusion coefficient values for Cr(VI) through the agarose diffusive layer were equal to 4.89±0.5×10(-6)cm(2)s(-1) and 3.95±0.02×10(-6)cm(2)s(-1) (T=23±1°C, I=0.03molL(-1) NaNO3) were obtained by using diffusion cell and immersion curves, respectively. The retention of Cr(VI) by the DE81 membrane in a synthetic sample and river water was not affected by the pH over a wide range 4-9). Recoveries of Cr(VI) between 90% and 120% from solutions of ionic strength ranging from 0.01 to 0. 5molL(-1) NaNO3 were achieved. Finally, the redox speciation analysis of Cr(III) and Cr(VI) in spiked river water and synthetic samples was performed with recoveries greater than 80% and 87% by using Chelex-100-DGT and DE81-DGT devices, respectively. Those results were in excellent agreement with the diphenylcarbazide spectrophotometric method. PMID:27154678

  8. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters

    Directory of Open Access Journals (Sweden)

    Ball James W

    2003-06-01

    Full Text Available A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange resin Bio-Rad™ AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted with 1 and 3 M KCl, respectively. Recovery ranged from 89 to 100%. Comparison of results for water samples collected from five pools in Yellowstone National Park between on-site IC analysis (U.S. Geological Survey mobile lab and IC analysis of resin-stored sample at SUNY-Stony Brook indicates 96 to 100% agreement for three pools (Cinder, Cistern, and an unnamed pool near Cistern and 76 and 63% agreement for two pools (Sulfur Dust and Frying Pan. Attempts to extract polythionates from the AG1-X8 resin were made using HCl solutions, but were unsuccessful. Bio-Rad™ AG2-X8, an anion-exchange resin with weaker binding sites than the AG1-X8 resin, is better suited for polythionate extraction. Sulfate and thiosulfate extraction with this resin has been accomplished with KCl solutions of 0.1 and 0.5 M, respectively. Trithionate and tetrathionate can be extracted with 4 M KCl. Higher polythionates can be extracted with 9 M hydrochloric acid. Polythionate concentrations can then be determined directly using ion chromatographic methods, and laboratory results indicate recovery of up to 90% for synthetic polythionate solutions using AG2-X8 resin columns.

  9. Selective separation of uranium using alizarin red S (ARS)-modified anion-exchange resin or by flotation of U-ARS chelate

    International Nuclear Information System (INIS)

    An alizarin red S (ARS)-modified anion exchange resin was prepared by a simple reaction of ARS with the anion exchange Doulite A101 and used for the efficient sorption of uranium from aqueous media. The effect of various parameters on the sorption of U(VI) (pH effect, sorption kinetics, resin capacity and breakthrough curves) was investigated. The modified resin sorbs U(VI) over a wide range of pH (2.8--5) with a maximum sorption capacity of 0.68 mmol/g at pH 3.2 to 4.0. Iron(III), Zr(IV), Ti(IV), Cu(II), and Th(IV) ions are also sorbed to different extents, but Be(II), Bi(III), Ca(II), Mg(II), Pb(II), Hg(II), Zn(II), Cd(II), Al(III), Mn(II), Co(II) and Ni(II) are not sorbed; thus, conditions for separating U(VI) from these metal ions have been identified. For eluting U(VI) from the resin, 0.2 mol/L HCl was used and the recovery recorded was as high as 99.9%. The use of ARS is extended to float uranium quantitatively and selectively from aqueous media at pH ∼ 4 by using oleic acid as a surfactant. The different parameters affecting the flotation process have also been investigated. Uranium(VI) has been effectively separated from natural water samples and certified uranium ores using both procedures

  10. Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters

    Science.gov (United States)

    Druschel, Greg K; Schoonen, Martin AA; Nordstrom, D Kirk; Ball, James W; Xu, Yong; Cohn, Corey A

    2003-01-01

    A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange resin Bio-Rad™ AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted with 1 and 3 M KCl, respectively. Recovery ranged from 89 to 100%. Comparison of results for water samples collected from five pools in Yellowstone National Park between on-site 1C analysis (U.S. Geological Survey mobile lab) and IC analysis of resin-stored sample at SUNY-Stony Brook indicates 96 to 100% agreement for three pools (Cinder, Cistern, and an unnamed pool near Cistern) and 76 and 63% agreement for two pools (Sulfur Dust and Frying Pan). Attempts to extract polythionates from the AG1-X8 resin were made using HCl solutions, but were unsuccessful. Bio-Rad™ AG2-X8, an anion-exchange resin with weaker binding sites than the AG1-X8 resin, is better suited for polythionate extraction. Sulfate and thiosulfate extraction with this resin has been accomplished with KCl solutions of 0.1 and 0.5 M, respectively. Trithionate and tetrathionate can be extracted with 4 M KCl. Higher polythionates can be extracted with 9 M hydrochloric acid. Polythionate concentrations can then be determined directly using ion chromatographic methods, and laboratory results indicate recovery of up to 90% for synthetic polythionate solutions using AG2-X8 resin columns.

  11. Rapid and simultaneous determination of neptunium and plutonium in environmental samples using anion exchange chromatographic and sequential injection setup combined with inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    Full text: This paper presents an automated analytical method for the rapid and simultaneous determination of Pu and Np in the environmental samples. Anion exchange chromatographic column was incorporated in a sequential injection system to actualize the automated separation of Pu isotpes along with 237Np from the matrix elements and interfering radionuclides. K2S2O5-conc. HNO3 was applied as redox reagents for the valence adjustment and stabilization of Pu(IV) and Np(IV). 242Pu preformed well as a tracer for both Pu isotopes and 237Np. It was observed that the cross-link and particle size of the resins had significant effluence on the separation efficiency and anion exchange resin Bio-Rad AG 1 x 4 with the particle size of 100-200 mesh was chosen as the optimum. The investigation on the capacity showed small-sized column packed with 2mL resin sufficed up to 50g of soil sample, which provides an advantage of low consumption of the resin and low generation of acid waste after the column washing. The analytical results for Pu and Np in three reference materials showed good agreement with the certified or reference values at the 0.05 significance level. Chemical yields of Pu and Np equally range from 80% to 100%, and the decontamination factors for uranium, thorium and lead were in the range of 103 to 104. The total time of separation for a single sample was < 2.5 hours, which extremely improve the analysis efficiency and reduces the labor intensity, as well as enables a rapid determination of Pu and Np in emergency situations. (author)

  12. Automated flow-based anion-exchange method for high-throughput isolation and real-time monitoring of RuBisCO in plant extracts.

    Science.gov (United States)

    Suárez, Ruth; Miró, Manuel; Cerdà, Víctor; Perdomo, Juan Alejandro; Galmés, Jeroni

    2011-06-15

    In this work, a miniaturized, completely enclosed multisyringe-flow system is proposed for high-throughput purification of RuBisCO from Triticum aestivum extracts. The automated method capitalizes on the uptake of the target protein at 4°C onto Q-Sepharose Fast Flow strong anion-exchanger packed in a cylindrical microcolumn (105 × 4 mm) followed by a stepwise ionic-strength gradient elution (0-0.8 mol/L NaCl) to eliminate concomitant extract components and retrieve highly purified RuBisCO. The manifold is furnished downstream with a flow-through diode-array UV/vis spectrophotometer for real-time monitoring of the column effluent at the protein-specific wavelength of 280 nm to detect the elution of RuBisCO. Quantitation of RuBisCO and total soluble proteins in the eluate fractions were undertaken using polyacrylamide gel electrophoresis (PAGE) and the spectrophotometric Bradford assay, respectively. A comprehensive investigation of the effect of distinct concentration gradients on the isolation of RuBisCO and experimental conditions (namely, type of resin, column dimensions and mobile-phase flow rate) upon column capacity and analyte breakthrough was effected. The assembled set-up was aimed to critically ascertain the efficiency of preliminary batchwise pre-treatments of crude plant extracts (viz., polyethylenglycol (PEG) precipitation, ammonium sulphate precipitation and sucrose gradient centrifugation) in terms of RuBisCO purification and absolute recovery prior to automated anion-exchange column separation. Under the optimum physical and chemical conditions, the flow-through column system is able to admit crude plant extracts and gives rise to RuBisCO purification yields better than 75%, which might be increased up to 96 ± 9% with a prior PEG fractionation followed by sucrose gradient step. PMID:21641435

  13. Determination of trace amount of titanium in 2.5% Nb-Zr alloy by anion exchange separation and sulfo salicylic acid photometry

    International Nuclear Information System (INIS)

    A trace amount of Ti in 2.5% Nb-Zr alloy can be determined by a combined method of the characteristic anion exchange separation of Ti from Nb and the absorption photometry of Ti with sulfo salicylic acid. The alloy (1g) was dissolved in 5 ml of HF (1 + 1), and 5 ml of HNO3 was added to them. The resultant 5M HF - 6M HNO3 mixed acid solution was passed into an anion exchange resin column with 10 mm internal diameter and 100 mm high, at the rate of 1 to 2 ml/min. Niobium was adsorbed on to the column, through which Ti passed. The collected passing and washing solutions were converted into H2SO4 medium by twice successive fuming treatments. The solution was transferred into a volumetric flask of 50 ml, and 10 ml of 10% sulfo salicylic acid in H2SO4 was added. Diluting to a mark with H2SO4, the solution was allowed to stand for 15 min. Titanium was then determined by measuring absorption intensity at the wavelength of 410 mm. The influence of coexisting elements on the coloration of Ti and some adsorption conditions of Nb was experimentally investigated by using 95Nb as a tracer. The experiment revealed that the removal of Nb is essential, and that higher HF concentration and lower HNO3 concentration contribute to higher Nb adsorption. A variable rate type cockless column is useful for this routine analysis. The standard deviation and the coefficient of variation of analysis are 1.3 and 4.06% respectively for the concentration level of 32 ppm Ti (NZ-3). (Iwakiri, K.)

  14. Simultaneous determination of iodide and iodate in povidone iodine solution by ion chromatography with homemade and exchange capacity controllable columns and column-switching technique.

    Science.gov (United States)

    Huang, Zhongping; Zhu, Zuoyi; Subhani, Qamar; Yan, Wenwu; Guo, Weiqiang; Zhu, Yan

    2012-08-17

    A simple ion chromatographic method for simultaneous detection of iodide and iodate in a single running was proposed, with columns packed with homemade functionalized polystyrene-divinylbenzene (PS-DVB) resins and column-switching technique. Homemade resins were functionalized with controllable amounts of quaternary ammonium groups. The low-capacity anion-exchange column and high-capacity anion-exchange column were prepared, due to the resins having different exchange capacities. With this method, iodide and iodate in povidone iodine solution were detected simultaneously in a short time with iodide being eluted off first. A series of standard solutions consisting of target anions of various concentrations from 0.01 mg/L to 100 mg/L were analyzed. Each anion exhibited satisfactory linearity, with correlation coefficient r ≥ 0.9990. The detection limits (LODs) for iodide and iodate obtained by injecting 100 μL of sample were 5.66 and 14.83 μg/L (S/N=3), respectively. A spiking study was performed with satisfactory recoveries between 101.2% and 100.6% for iodide and iodate. PMID:22771256

  15. Application of ion exchange and extraction chromatography for 226Ra determination in natural waters using HR-ICP-MS

    International Nuclear Information System (INIS)

    We describe a chemical separation procedure for determination of 226Ra in natural water samples with high-resolution ICP-MS (HR-ICP-MS). The proposed procedure is focused on the application of ion exchange and extraction chromatography for pre-concentration and separation of Ra from water samples. It was clear that the sensitivity of HR-ICP-MS was sufficient for 226Ra determination in natural water after selective extraction of the analyte. The Diphonix ion-exchange resin was used for alkali earth cations extraction from natural water samples, followed by the separation of Ba and Ra from Mg, Ca and most of Sr using the Muromac cation exchange resin. Final separation of Ra from Ba and the rest of Sr was performed by the selective retention of Ba and Sr on the Sr-Spec extraction chromatographic resin. Overall chemical recovery was estimated to be >95%, and 226Ra pre-concentration factor of 200 was achieved by the developed procedure. (author)

  16. Papaverine PVC Membrane Ion-Selective Electrodes Based on its Ion-Exchangers with Tetraphenylborate and Tetrathiocyanate Anions

    International Nuclear Information System (INIS)

    The construction and general performance of novel potentiometric membrane ion selective electrodes for determination of papaverine hydrochloride has been described. They are based on the formation of the ion association complexes of papaverine (PA) with tetraphenylborate (TPB)(1) or tetrathiocyanate (TTC)(2) counter anions as electro-active material dispersed in a PVC matrix. The electrodes show fast, stable, near Nernstian response for 1x10-2 to 6x10-5 M and 1x10-2 to 1x10-5 M for PA-TPB and PA-TTC respectively at 25 0C over the pH range of 3-5.0 with a cationic slope of ∼ 56.5±0.5 mV/decade for both sensors respectively. The lower detection limit is 4x10-5 and 8x10-6 M for PA-1 and PA-2 respectively with fast response time ranging from 20-45 sec. Selectivity coefficients for PA relative to a number of interfering substances were investigated. There is a negligible interference from the studied cations, anions, and pharmaceutical excipients. The determination of 4.0-3000.0 μg/ml of PA in aqueous solutions shows an average recovery of 99.1 % and a mean relative standard deviation of 1.4 at 100 μg/ml. The direct determination of PA in some formulations (Vasorin injection) gave results that compare favorably with those obtained using the British Pharmacopoeia method. Potentiometric titration of PA with sodium tetraphenylborate and potassium thiocyanate as titrants utilizing the papaverine electrode as an end point indicator electrode has been carried out

  17. 超声提取-离子色谱法测定蜂蜜柚子茶中的可溶性糖%Determination of Soluble Sugars in Honey Pomelo Tea by Anion Chromatography with Ultrasonic Extraction

    Institute of Scientific and Technical Information of China (English)

    许丽; 周光明; 余娜; 张丽贤

    2011-01-01

    建立超声提取-高效阴离子交换-脉冲安培检测(HPAE-PAD)同时分离并测定蜂蜜柚子茶中可溶性糖的分析方法.采用METROSEP CARB 1(150mm×4.0mm)分离柱,对分离条件进行了优化,确定淋洗液为5.0mmol/L的NaOH溶液,流速为1.0mL/min.蔗糖、葡萄糖、果糖的检出限分别为0.2,0.1,1.0μg/mL.混合标准溶液连续6次进样,峰高相对标准偏差为1.56%3.40%,回收率为86.80%98.80%.该方法样品前处理简单,灵敏度高,为蜂蜜柚子茶的质量检测提供了一个简单有效的方法.%A method for the determination of soluble sugars in honey pomelo tea by high performance anion exchange chromatography with ultrasonic extraction and pulsed amperometric detection(HPAE-PAD) is described in this paper.The separation conditions were investigated on METROSEP CARB 1(150 mm×4.0 mm) column.The optimal separations were achieved with 5.0 mmol/L NaOH as the eluent at a rate of 1.0 mL/min.The detection limits of sucrose,glucose and fructose were 0.2 μg/mL,0.1 μg/mL and 1.0 μg/mL,respectively.The RSDs(relative standard deviation) of peak height for six consecutive determinations varied from 1.56% to 3.40%,with a recovery of 86.80%-98.80%.The above method proved to be simple and highly sensitive for sample pretreatment and is,therefore,recommended for quality inspection of honey pomelo tea.

  18. Deuterium Exchange in Ethyl Acetoacetate: An Undergraduate GC-MS [Gas Chromatography-Mass Spectroscopy] Experiment

    Science.gov (United States)

    Heinson, C. D.; Williams, J. M.; Tinnerman, W. N.; Malloy, T. B.

    2005-01-01

    The role of ethanol O-d in nullifying the deuterolysis may be demonstrated by determining that transesterification of methyl acetoacetate of the ethyl ester occurs as well as deuterium exchange of the five acetoacetate hydrogens. The significant acidity of the methylene protons in the acetoacetate group, the efficacy of base catalysis, the role of…

  19. Characterization of Anion Exchange Membrane Containing Epoxy Ring and C–Cl Bond Quaternized by Various Amine Groups for Application in Fuel Cells

    Directory of Open Access Journals (Sweden)

    Sung Kuk Jeong

    2015-07-01

    Full Text Available Anion exchange membranes were synthesized from different compositions of glycidyl methacrylate (GMA and vinylbenzyl chloride (VBC, with constant content of divinyl benzene (DVB by radical polymerization using benzoyl peroxide (BPO on non-woven polyethylene terephthalate (PET substrate. Polymerized membranes were then quaternized by soaking in trimethylamine (TMA, triethylamine (TEA, tripropylamine (TPA, and 1,4-diazabicyclo [2.2.2] octane (DABCO. Characteristics of membranes were confirmed by Fourier transform infrared spectroscopy, water uptake, ion exchange capacity, ion conductivity, thermal, and alkaline stability. The results revealed that membranes quaternized by TPA and DABCO showed high affinity when GMA content was 15 wt% and 75 wt%, respectively. IEC and ion conductivity of membranes quaternized by TPA were 1.34 meq·g−1 and 0.022 S·cm−1 (at 60 °C, respectively. IEC and ion conductivity of membranes were quaternized by DABCO were 1.34 meq·g−1 and 0.021 S·cm−1 (at 60 °C, respectively. The results indicate that the membrane containing GMA 15 wt% quaternized by TPA showed the highest thermal stability among membranes and exhibited high ion conductivity compared to existing researches using GMA, VBC, and DVB monomers.

  20. New inorganic (an)ion exchangers based on Mg–Al hydrous oxides: (Alkoxide-free) sol–gel synthesis and characterisation

    KAUST Repository

    Chubar, Natalia

    2011-05-01

    New inorganic ion exchangers based on double Mg-Al hydrous oxides were generated via the new non-traditional sol-gel synthesis method which avoids using metal alkoxides as raw materials. Surface chemical and adsorptive properties of the final products were controlled by several ways of hydrogels and xerogels treatments which produced the materials of the layered structure, mixed hydrous oxides or amorphous adsorbents. The final adsorptive materials obtained via thermal treatment of xerogels were the layered mesoporous materials with carbonate in the interlayer space, surface abundance with hydroxylic groups and maximum adsorptive capacity to arsenate. Higher affinity of Mg-Al hydrous oxides towards H2AsO4- is confirmed by steep adsorption isotherms having plateau (removal capacity) at 220. mg[As]. gdw-1 for the best sample at pH = 7, fast adsorption kinetics and little pH effect. Adsorption of arsenite, fluoride, bromate, bromide, selenate, borate by Mg-Al hydrous oxides was few times high either competitive (depending on the anion) as compare with the conventional inorganic ion exchange adsorbents. © 2011 Elsevier Inc.