Extraction of Pt(IV), Pt(II), and Pd(II) from Acidic Chloride Media Using Imidazolium-Based Task-Specific Polymeric Ionic Liquid

As an excellent separation material to recover platinum group metals (PGMs), imidazolium-based task-specific polymeric ionic liquid (CP-AMIN) was successfully synthesized and characterized by SEM and FT-IR. The effects of temperature, pH, reaction time, CP-AMIN amount, and concentration of chloride ion were discussed during the process of extraction of Pt(IV), Pt(II), and Pd(II) from acidic chloride media. It shows high extraction efficiency under various conditions, suggesting CP-AMIN has strong adaptability of environment. CP-AMIN also presents excellent selectivity for PGMs in the solutions with coexisting metal ions (Ni2+,Mn-2(+),Cu2+,Cd2+,Co-2(+); and Cr3+), and it indicates the CP-AMIN process efficient task specificity. Notably, the acidic thiourea can desorb PGMs from CP-AMIN almost completely. After seven cycles of adsorption-desorption experiments, the extraction efficiencies still maintain above 85%. This suggests that CP-AMIN also exhibits excellent recyclability. Meanwhile, due to its being easy to handle, safe, and environmentally friendly, the task-specific polymeric ionic liquid promises great potential to recover PGMs from aqueous phase.