Selective enrichment of low concentration Au(iii) from acidic chloride media by poly ionic liquid sorbent

Abstract

Hydrophilic ionic liquid (imidazolium chloride, imCl)–polyvinyl chloride ionomer (imCl–PVC) as a green sorbent to recover precious gold from acidic chloride solution was characterized by SEM, FTIR, XPS and NMR. Potential rate controlling steps of the adsorption process are modeled by the best-fit of the kinetic curve (pseudo-second-order), and isotherm (Langmuir) parameters. The wide range of pH (1–6), competing heavy metals (Cu, Cd, Co, Cr, Ni, and Mn) and the high Cl⁻ concentration showed least interference. The results of XPS analysis showed that the Au(III) ion sorption was an electrostatic attraction–reduction process. Moreover, a stripping agent (thiourea) desorbed 88% of ionic gold. The spent adsorbent could be regenerated well and retained above 64% of the recovery efficiency at the end of the fifth cycle. The performance characteristics of imCl–PVC to enrich gold can be applied in the treatment of gold-contaminated water.