Polymer-supported quaternary ammonium ionic liquid for efficient capture of Pt(IV)

Developing efficient materials capable of selectively extracting platinum from secondary resources represents a critical step toward addressing the global shortage of platinum resources and environmental concerns. In this study, we report the rational design and successful synthesis of a novel polymer-supported quaternary ammonium ionic liquid (CPR-BDEA) for the selective separation and recovery of platinum (Pt(IV)). CPR-BDEA exhibited an impressive maximum adsorption capacity 411.5 mg/g (pH=4) and maintained excellent selectivity for Pt(IV) even in the competitive multi-ion systems. Its practical applicability was validated by effective Pt(IV) capture from real leaching solutions derived from e-waste and spent automotive catalyst. Furthermore, CPR-BDEA exhibited excellent regenerability and still maintained a high recovery efficiency for Pt(IV) after five cycles. Finally, with the aid of various characterization technologies and density functional theory (DFT), the adsorption mechanism between CPR-BDEA and Pt(IV) was revealed detailly, including electrostatic attraction, hydrogen bonds and van der Waals between the side chain of CPR-BDEA and Pt(IV), ion exchange and other interactions. It is expected that this study would provide fundamental insights into the design and preparation of quaternary ammonium salt functionalized materials and contribute to the development of sustainable strategies for the selective separation of precious metals from secondary resources.