Exploring imidazolium-based poly(ionic liquids) as adsorbents for Pt(IV) removal: The impact of N3 substituents

Imidazolium-based poly(ionic liquids) (PILs) have been explored as adsorbents for metal ions. Here, we investigate the relationship between the N3 substituent of the imidazole groups and the adsorption properties of PILs on Pt(IV). We synthesized a series of modified adsorbents (PIL-MMIP, PIL-TBIP, PIL-MEIP, and PIL-IM) by grafting imidazole groups with different N3 substituents onto chloromethyl polystyrene. Next, the influence of key adsorption parameters, such as hydrochloric acid concentration, Cl- concentration, and adsorption time, was investigated. Furthermore, structural characterization (FTIR, XRD, XPS, SEM, TGA, BET, and elemental analysis) and density functional theory (DFT) calculations were performed. The results indicated that the electrostatic potential of the adsorbent and interactions between the adsorbent and PtCl62- affected the adsorption performance of Pt(IV). This study provides molecular-level insights into the relationship between the N3 substituent of the imidazole groups and adsorption performance to guide the design of new Pt(IV) adsorbents and predict their physicochemical properties.