Guanidinium functionalised silica-based anion exchangers significantly improve the selectivity of platinum group metal recovery from process solutions

Guanidinium-containing silica-based anion exchangers show great potential for the selective extraction of platinum group metals from authentic precious metal refinery solutions. The pH range for selective palladium extraction over Cu and Ni was found to be increased by as much as 2 pH units compared to previously reported (poly)amine-containing ion exchangers without efficiency loss.