Ion exchange characteristics of palladium from nitric acid solution by anion exchangers

Radioactive high-level liquid wastes contain significant quantities of platinum group metals (PGM) such as Pd(II), Rh(III) and Ru(III). The PGM are produced as fission products in nuclear reactors. In this study, batch and column experiments were carried out to investigate the ion exchange characteristics of Pd(II), including the effects of the ionic group of ion exchangers, solution temperature, and the concentration of nitric acid by various anion exchangers such as IRN 78 and Dowex 1x8 and also the elution characteristics of Pd(II) by various eluents for the determination of optimal separation conditions. Anion exchangers such as Dowex 1x8 with the ionic group of quaternary methyl ammonium showed a higher capacity than anion exchangers such as IRN 78 with amine group for the adsorption of Pd(II) from nitric acid solution. The optimal nitric acid concentration was shown to be in 2-3 M. The adsorbed Pd(II) was effectively eluted out by 0.5 M thiourea and 0.1 M nitric acid mixed solution.