Zinc oxide templating of porous alginate beads for the recovery of gold ions

In this study, a novel porous alginate adsorbent was prepared by zinc oxide templating to selectively adsorb Au (III) ions from multi-metallic solutions under acidic condition. Due to the porous structure of the prepared sorbent, high uptake capacity and fast adsorption kinetics of Au (III) were achieved, which renders the prepared adsorbent great potential for practical applications in fixed-bed columns for large-scale applications. The adsorption of Au (III) by the prepared adsorbent led to the reduction of Au (III) to metallic gold. Adsorption and reduction of Au (III) in the process are mediated by the ionic and covalent interaction between Au (III) ions and the protonated functional groups on the modified alginate.