Recovery of silver from nickel electrolyte using corn stalk-based sulfur-bearing adsorbent

A renewable and recyclable adsorbent was synthesized by introducing thiol (-C-SH), episulfide (C-S-C ring) and thion (-C = S) groups onto the surface of corn stalks with epithiochlorohydrine as a crosslinker (OCS-ET-TU). The adsorption capacity of OCS-ET-TU for [AgCl4](3-) reached to 79.94 mg-g(-1) at the acid concentration of 1.0 mol.L-1 when the concentrations of Cu(II) and Ni(II) all reached to 10,000 mg.L-1; the maximum selectivity coefficients of the OCS-ET-TU for Ag(I)/Cu(II) and Ag(I)/Ni(II) achieved to 2.95 and 3.37, respectively. The FT-IR and XPS results showed that [AgCl4](3-) as soft acid could easily interact with the sulfur-containing groups belonging to the OCS-ET-TU as soft base. The adsorption and regeneration results of corn stalk-based OCS-ET-TU presented that it can potentially apply for recovery of trace amount of silver anions. The investigation provides a new and high-efficient biomaterial to enrich Ag(I) from nickel electrolyte with high concentrations of copper, iron and nickel.