Phosphorus-Based Polymers for Selective Capture of Platinum Group Metals

This work addresses the selective recovery of platinum group metals (PGMs) from aqueous streams, a critical issue within the recycling and metal refining industries aiming to lose zero of the value contained. Herein, selective PGM capture was investigated using three metal-capturing polymeric resins from different manufacturers: a special anion exchanger (Dow), an S-containing chelating resin (Lanxess), and a phosphine oxide containing coordinating resin (Magpie Polymers). The relative affinity of these different materials for the PGMs, as well as copper, was compared under various conditions. It was found that the phosphine oxide based material was the most suitable for the selective capture of PGMs from an oxidizing solution containing high concentrations of copper and counterions. Theoretical calculations using density functional theory (DFT) have shown that the most likely binding of PGMs to this material is a bidentate coordination via the phosphine oxide groups.