Ethylenedioxythiophene-Based Conjugated Organic Polymers for Gold Recovery from Electronic Waste

Gold, as a precious metal, holds irreplaceable significance in financial systems, the electronics industry, and cutting-edge technologies due to its unique physicochemical properties. To address the technical demands for gold recovery from electronic waste, we designed and synthesized ethylenedioxythiophene-functionalized conjugated organic polymers (EDOT-COPs) as Au(III) adsorbents. EDOT-COPs possess moderate porosity, thermal stability up to 350 °C, and chemical stability in acidic environments. As for the adsorption performance, EDOT-COPs achieve Au(III) uptake capacities exceeding 1700 mg g^-1 and selectively remove more than 96% of Au(III) from the mixed solutions containing eight competing metal ions such as Cu(II), Ni(II), and Pb(II). After eight consecutive adsorption-desorption cycles, EDOT-COPs still maintain high adsorption efficiency and good structural integrity. Mechanistic studies reveal that there are strong coordination bonds between EDOT groups and AuCl₄^- complexes in acidic media, along with the partial reduction of adsorbed Au(III) species. Furthermore, EDOT-COPs also demonstrate selective gold recovery from acid leachates. This work highlights the potential of functional-group-directed polymer design for developing efficient and stable adsorbents for precious metal recovery.