Rapid, Selective Extraction of Trace Amounts of Gold from Complex Water Mixtures with a Metal-Organic Framework (MOF)/Polymer Composite

With the ever-increasing production of electronics, there is an ensuing need for gold extraction from sources other than virgin mines. Currently, there are no technologies reported to date that can effectively and selectively concentrate ultratrace amounts of gold from liquid sources. Here, we provide a blueprint for the design of several highly porous composites made up of a metal-organic framework (MOF) template and redox active, polymeric building blocks. One such composite, Fe-BTC/PpPDA, is shown to rapidly extract trace amounts of gold from several complex water mixtures that include wastewater, fresh water, ocean water, and solutions used to leach gold from electronic waste and sewage sludge ash. The material has an exceptional removal capacity, 934 mg gold/g of composite, and extracts gold from these complex mixtures at record breaking rates, in as little as 2 min. Further, due to the high cyclability, we demonstrate that the composite can effectively concentrate gold and yield purities of 23.9 K.