Synthesis of N-(3-aminopropyl)imidazole-based poly(ionic liquid) as an adsorbent for the selective recovery of Au(iii) ions from aqueous solutions

Abstract

The synthesis of a novel poly(ionic liquid) adsorbent (PIL-APIBCl) through the modification of poly(styrene-co-maleic anhydride) (PSMA) composites with N-(3-aminopropyl)imidazole (API) and benzyl chloride (BCl) is presented. The structural analysis was carried out by nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and Fourier transform infrared (FT-IR). Batch adsorption experiments revealed that the investigated adsorbent exhibited good selectivity and a high adsorption capacity of 236.68 mg g⁻¹ towards tetrachloroaurate (Au(III)) ions at pH 1.0 over a wide temperature range. The adsorption isotherms and kinetics of Au(III) on the PIL-APIBCl were fitted well by the Langmuir isotherm model and pseudo-second-order model, respectively, indicating successful chemical adsorption of Au(III) ions on the adsorbent surfaces. According to FESEM, FT-IR, XPS and NMR analysis, the adsorption mechanisms of Au(III) on PIL-APIBCl could be ascribed to electrostatic and intermolecular interactions. Therefore, due to its good cyclability and low cost, PIL-APIBCl is a promising adsorbent for Au(III) recovery from wastewater on a large scale.