Separation of platinum(IV) and rhodium(III) from acidic chloride solution by ion exchange with anion resins

Ion exchange experiments have been done to separate Pt(IV) and Rh(III) from chloride solution. Loading of the two metals into anion exchange resins, such as AG1-x2, AG1-x8 and AGMP-1 resin, was investigated in the HCl concentration range from 0.1 to 5 M. The concentration ratio of Pt and Rh in the chloride solution was fixed at 10:1. It was found that the loading of Pt into the resins followed Langmuir isotherm. The resins employed in this study had selectivity for Pt over Rh. The concentration of HCl had a pronounced effect on the loading of the two metals and Pt was effectively separated from Rh at low concentration of HCl. Batch experiments indicated that AG1-x8 resin was the most effective in separating Pt and Rh in our range. Continuous experiments with AG1-x8 resin verified that complete separation of Pt from Rh was possible. The loaded AG1-x8 resin was successfully regenerated by elution with thiourea.