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Abstract  

The absorption effect of 5% w/w non-proliferative cell suspensions of Mycobacterium smegmatis on labelled solutions of Eu3+ ions, both alone and in admixtures with Am3+, Co2+ and Cs+, was studied at pH 1.0 as a function of time and cationic concentration. For 10 M concentrations of Eu, Co and Cs, selective adsorption of the trivalent lanthanide and actinide ions was practically quantitative after 90 min; no significant adsorption was observed for cobalt and cesium ions. Column adsorption measurements with the mycobacterial biomass showed that desorption of the M3+ ions did not occur at less than 2M HCl and remained incomplete even at higher acidities.

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Abstract  

The complex formation of Eu(III) by bicarbonate/carbonate ions has been studied at 0.1 M ionic strength and 25°C using synergistic solvent extraction system of 1-nitroso-2-naphthol and 1,10-phenanthroline in chloroform. Concentrations of bicarbonate (5·10–3 to 1·10–1 M) and carbonate (5·10–4 to 1·10–2 M) ions in the aqueous phase have been varied in the pH range of 8.0 to 9.1 to simulate ground and natural water compositions. Under these conditions, the following species have been identified: Eu(HCO3)2+, Eu(HCO3)2 +, Eu(CO3)+ and Eu(CO3)2 . Their conditional formation constants (log ) have been calculated as 4.77, 6.74, 6.92 and 10.42, respectively. These values suggest that the carbonate complexes of Eu(III) are highly stable.

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Abstract  

Various chrysolite-asbestos from Canada and Russia, asbestos plate and, dry as well as wet manufactured asbestos, were analyzed for Hg, Fe, Eu, La and K by the neutron activation method. Following concentration values were found: Hg 0.01–0.46 ppm, Fe 4818–32738 ppm, Eu 0.02–0.125 ppm, La 0.061–0.874 ppm, K 14.829–358.5 ppm. Statistically significant differences /t=0.05/ in Hg, Fe, Eu, La and K contents were found in the different asbestos samples. The concentration of Hg, Fe, Eu in Italian asbestos were considerably higher than in Canadian chrysolite. High Concentration of La, K were found in Austrian asbestos plate.

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Abstract  

The partition of Eu(III) between benzene containing solvating extractants (TBP, TOPO, dioctylsulfoxide) and aqueous nitrate, perchlorate and thiocyanate solutions containing various organic solvents miscible with water (alcohols, acetone, acetonitrile, ethylene glycol, dimethyl sulfoxide and dimethylformamide) was investigated. Depending on the specific extraction system, the presence of organic solvents in the mixed phase showed various effects on the distribution ratio of Eu(III). These were discussed in terms of solute-solvent interactions. The results in the systems containing dimethylformamide and dimethyl sulfoxide indicated complexation of Eu(III) with these solvents in the polar phase.

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Abstract  

The extraction of Nd3+ and Eu3+ from aqueous media containing selected diamine ligands by HDEHP solution in benzene has been investigated. It is found that the presence of the diamine in the aqueous phase enhances the extraction of both Nd3+ and Eu3 in the organic phase. The possible explanation for this behaviour is presented and a mechanism based on extraction of an adduct of the type MH3(DEHP)6. B is found to be the most probable.

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Abstract  

Previously it was found that in the extraction separation on lanthanides and americium from acidic nitrate solutions of nuclear fission products, benzyldimethyldodecylammonium nitrate gives high values of separation coefficients. The change in the extraction capacity of this agent and its solutions in benzene in the extraction of Eu(III) and Am(III) was investigated as a function of the adsorbed dose of ionizing radiation. The slight reduction in the extraction of both metals is caused mainly by the radiolysis products of nitric acid in the organic phase that enter into secondary reactions with both the solvent and the extractant. Comparison of the radiation stability of benzyldimethyldodecylammonium nitrate systems with tertiary amines show that the changes in distribution coefficients in the range of investigated absorbed doses are significantly lower in the former case. The investigated system may be characterized as radiation stable up to about 100 kGy even in the presence of nitric acid.

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Abstract  

The extraction of Tm with HDEHP from H2SO4, HCl and HBr is inversely proportional to the third power of the hydrogen ion concentration while the extraction is small with HDEHP, LA-2 and TBP from binary mixtures of acids. The extraction of both Eu and Tm with HDEHP from KI solutions decreases in the presence of small concentrations of H2SO4. The decrease is sharper in case of Eu leading to high separation factors between Eu and Tm from KI−H2SO4 mixtures.

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Abstract  

The extraction of Eu with Amberlite LA-2, TBP and HDEHP from HF, HCl, HBr, H2SO4, CH3 COOH and KI solutions was investigated. The extraction of Eu with TBP and LA-2 is small over a wide range of concentrations. The extraction of Eu with HDEHP from HCl, HBr, and H2SO4 is inversely proportional to the third power of the acid concentration, while the extraction from KI is proportional to the square of the extractant concentration. The extraction by the three extractants from H2SO4 in presence of small amounts of hydrogen halides is small. These extraction data can be used to separate Eu from Th and many of the fission products. The presence of water-miscible alcohols and acetone generally increases the extraction of Eu from H2SO4 and KI solutions.

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Abstract  

Distribution of Hg2+, Co2+, Sc3+ and Eu3+ between the cation exchanger Dowex-50X8, [H+] (100–200 mesh), and 1M HNO3 solution containing different benzylamine (BA) concentrations has been studied. The distribution coefficient, D, for Co2+, Sc3+ and Eu3+ is very small and does not vary seriously with the BA concentration. It is also found that Hg2+ is highly taken by the resin from the media studied. In this respect, D increases with increasing BA concentration to reach a maximum at 0.5% BA in 1M HNO3. This behaviour is explained by the exchange of molecular species between the cation exchanger and the aqueous phase. Based on the results, a radiochemical separation procedure for the selective isolation of Hg2+ from Co2+, Sc3+ and Eu3+ has been developed. The radiochemical purity is not less than 99.8% and the chemical yield more than 95% for the separated203Hg.

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