Thia-crown ether functionalized mesoporous silica (SBA-15) adsorbent for selective recovery of gold (Au3+) ions from electronic waste leachate

Abstract

Abstract The rapid production rate of electrical and electronic devices demands for gold (Au) recovery and recycling from their generated wastes. However, achieving adsorbents with high selectivity for Au remains a challenge. Herein, an Au3+-selective composite adsorbent (15TCE@SBA-15) was successfully fabricated through covalent attachment of thia-crown ether (15TCE) as ligand on mesoporous silica support SBA-15. The physicochemical properties of 15TCE@SBA-15 were extensively examined using FT-IR, SAXRD, TGA, FE-SEM, EDS mapping, surface area (BET), and pore size distribution (BJH, NLDFT) analysis. To evaluate its ability to selectively capture Au3+, adsorption experiments were conducted. The results revealed that 15TCE@SBA-15 was able to capture 126 mg of Au3+ per gram of sample. More importantly, it was highly selective towards Au3+ with distribution coefficient of KD ~2439 L g−1 vs. other cations (i.e. Pd2+, Pt4+, Ni2+, Pb2+, Cu2+, Zn2+) present in spent mobile phones with KD values