Developing a Hyper-Crosslinked Polymer for Environmentally-Friendly Au(I) Capture

The ever-rising global demand for gold1 has prompted extensive research into methods to extract and purify gold ore efficiently with minimal environmental impacts.2,3,4 At present, the leading gold extraction method is cyanidation2,4 wherein poisonous alkaline cyanide salts are used to leach gold ions from the ore. Unfortunately, cyanidation produces a variety of toxic byproducts and has become increasingly controversial due to its devastating environmental impacts. Several less-toxic leaching agents such as thiosulfate,3,4 thiourea,5 and halides have been proposed as alternatives to cyanide in gold leaching.2 Unfortunately, none of these are particularly effective at selectively forming stable gold-anion complexes that can be separated from other metal-anion impurities. To this end, I have developed a thiol-functionalized hyper-crosslinked polymer (HCP-SH) that can be used as an economical and environmentally-friendly sorption agent to capture AuI ions from a mixture of soluble metal salts.