THE SORPTION OF CATIONIC SPECIES ON HYDROUS TIN DIOXIDE

This paper discusses some recent research work into the sorption of ca tions both hydrolysable and those that are not, on to a hydrous tin ox ide and a silica-tin ion exchanger. The ions studied are mostly those that might be encountered in a radioactive waste streams; such as the non-hydrolysable ions Sr++ and Cs+, hydrolysable species such as Co+and Eu3+ and complexes such as Ru(NO)(3+). Complete isotherm data have been generated for some of the ions considered. These can be correlat ed by a 'Langmuir' isotherm for quite a wide range of solution pH. Fro m this data the oxide capacity for the ion can be determined. Uptake o f soluble cationic species always increases with solution pH. However for most metallic cations the exchangers are able to adsorb anionic sp ecies by the complex formation at low solution pH. Elution of the ions with acid and a complexing agent such as EDTA is also considered. Fin ally 'synergistic effects', when mixtures of cations are contacted wit h the exchangers are considered.