Utilization of natural food wastes as new adsorbent for precious metal ions

Use of biomass as alternatives to petrochemicals has attracted a broad range of scientific and industrial interests. We propose here a novel environmentally-friendly recycle system for precious metal ions such as gold and platinum ions using protein-rich biomass. My keynote lecture is composed of three pieces; (1) selective adsorption of precious metal ions onto proteins, (2) the mechanism study of the metal ion adsorption, and (3) demonstration of selective recovery of precious metal ions from actual copper refining solution. A biomass was found to have an extremely high loading potential 250g/kg-biomass for gold ions. This article describes not only scientific investigations but also practicality of the strategy. The recycle system proposed here will enable selective recovery of precious metal ions from industrial wastewater without extra emissions of CO2.