Selective cation exchange isolation of radioactive mercury from cobalt, scandium and europium

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.