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Abstract  

Adsorption of carrier-free radiotracers 181W and 93mMo produced in the 181Ta(p, n) and natNb(p, n) reactions, respectively, on anion-exchange resin was studied in mixed solution of HF and HNO3 in a concentration range of 10−4–10−1 M HF/0.1 M HNO3. Distribution coefficients (K d) of 181W and 93mMo at 70 °C showed the V-shaped variation with the minimum at around 10−1 M HF/0.1 M HNO3, although variation of the K d values for 93mMo was quite small compared with that for 181W. Formation of oxofluoro complexes for W and Mo is briefly discussed.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: A. Toyoshima, K. Tsukada, H. Haba, M. Asai, S. Goto, K. Akiyama, I. Nishinaka, S. Ichikawa, Y. Nagame, and A. Shinohara

Abstract  

The anion exchange behavior of 255No produced by the 248Cm(12C,5n) reaction has been investigated in 11.5M HCl, 4M HCl and 8M HNO3 to deduce the behavior of 'primordial 257No' produced via 248Cm(18O,5n)261Rf 257No before anion exchange separation in the 261Rf experiment. It was found that 255No is mostly eluted from the anion exchange column with these solutions. The contribution of 'primordial 257No' to the -decay events of 261Rf in the 261Rf experiment was evaluated based on the present results.

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Anion exchange in mixed solvent systems

VII. Kinetics of anion exchange of some corrosion and fission products

Journal of Radioanalytical and Nuclear Chemistry
Author: V. Koprda

Abstract  

The diffusion of chlorocomplexes of some corrosion and fission products in anion exchange beads has been studied in mixed solvent media. The effects of variables on the kinetics of the exchange process by the batch and flow technique were examined. The strongly basic anion exchanger Dowex 2X8 in its Cl form was used in organic solvent—water—hydrochloric acid solutions. The dependence of the exchange rate on temperature, the viscosity of the solution, the mean resin particle diameter and the composition of the solution was studied. Film and particle diffusion coefficients were calculated from the experimental data. The results provide valuable data for the design of separation procedures.

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Abstract  

The diffusion of cobalt chloro complexes in anion-exchange beads has been studied in mixed solvent media. The effects of variables on the kinetics of the exchange process by the batch technique were examined. The strongly basic anion-exchanger Dowex 2X8 in its Cl form was used in ethyl alcohol-water-hydrochloric acid solutions. The rate laws were verified experimentally. The dependence of the exchange rate on the temperature, the viscosity of the solution, the mean resin particle diameter and the composition of the solution was studied.

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Anion-exchange in mixed solvent systems

V. Separation scheme for fifteen radionuclides by ion-exchange

Journal of Radioanalytical and Nuclear Chemistry
Authors: M. Szlaurová, V. Koprda, and M. Fojtík

Abstract  

A quantitative separation scheme for 15 radionuclides is presented. The scheme is based on group separation by means of anion-exchange resins using mixed solvent systems and subsequent separation of the groups into individual components by means of change of both eluting agent and resin type. The optimum working conditions for separation are established. Separation procedures are of good reproducibility and practically quantitative.

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Abstract  

Additional1 bifunctional anion-exchange resins have been designed, synthesized and evaluated for their ability to take up Pu(IV) from nitric acid solutions. Bifunctionality is achieved by adding a second anion-exchange site to the pyridine nitrogen (also an anion-exchange site) of the base poly(4-vinylpyridine) resin. Previous work focused on the effect of varying the chemical properties of the added site along with the length of an alkylene ‘spacer’ between the two sites. Here we examine four new 3- and 4-picolyl derivatives which maintain more rigidly defined geometries between the two nitrogen cationic sites. These materials, which have the two anion-exchange sites separated by three and four carbons, respectively, exhibit lower overall Pu(IV) distribution coefficients than the corresponding N-alkylenepyridium derivatieves with more flexible spacers. Methylation of the second pyridium site results in a ca. 20% increase in the Pu(IV) distribution coefficients.

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Pyrolysis-gas chromatography was used in the study of the thermal behaviour of some acrylic anion-exchangers for identification of the thermal decomposition products and their percentage estimation. The acrylic anion-exchangers were prepared by aminolysis of cross-linked acrylic ester copolymer with difunctional amines. The pyrolysis-gas chromatography studies, coupled with data obtained by thermogravimetry, showed that the acrylic anion-exchangers first lose the water easily absorbed from the air, and the decomposition starts at temperatures above 100°. The great number of decomposition products identified in the pyrograms on the thermal degradation of acrylic anion-exchangers indicated a complex degradation mechanism, with important variations in the contents of the evolved amine compounds.

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Abstract  

The separation of strontium and yttrium from calcium on the anion exchanger column with alcohol solution of nitric acid as eluent may be described by Glueckauf's model of elution chromatography. Experimental and theoretical results have shown that this separation is characterized by a small number of theoretical plates of the separation column. This model may also be applied for the simulation of the separation of strontium and yttrium from calcium in the strontium isolation from natural samples. The model parameters may be used for the assessment of the optimum column dimension and the optimum working conditions for the isolation of radioactive strontium and yttrium from natural samples.

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Abstract  

Organic anion exchange resins, loaded with99Tc pertechnate were incorporated into polymer modified cements and BFS/OPC(9∶1) cements. The composites formed were tested for initial compressive strenghts, underwater and radiation stabilities and leach rates. IAEA standard leach testing was with simulated sea and ground waters. Ground water leaching was also carried out on composites subjected to 1.1 MGy (γ). Polymer modified composites performed better than the BFS/OPC mix under all the conditions studied and, in most cases, were able to encapsulate high resin loading.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: E. Tereshatov, H. Bruchertseifer, M. Voronyuk, G. Starodub, O. Petrushkin, and S. Dmitriev

Abstract  

Isocratic anion exchange separations of Group V elements from solutions containing HF have been considered for the development of Db aqueous phase chemistry experiments. Separation of Nb/Ta from an HF/NH4F system has been demonstrated but has limited utility due to interferences with alpha and spontaneous fission (SF) source preparation. The physical parameters associated with ion exchange chromatography have been optimized for the separation and sequential isolation of Pa, Nb and Ta from mixed HF/HNO3 solutions. A suitable procedure incorporating a series of successive chemical separation techniques, i.e. precipitation and ion exchange chromatography, has been suggested for off-line Db characterization studies.

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