Phenanthrenequinone-functionalized covalent microporous polymers for photo-enhanced gold recovery from waste electronic devices

Using green and effective photocatalytic reduction technology to reclaim gold from electronic waste has enormous economic benefits and is conducive to alleviating environmental problems and resource pressure. Therefore, the construction of photocatalysts with high photocatalytic activity, low cost, and high selectivity is highly desirable for the extraction of gold from discarded electronic devices. Herein, we present the implementation of D-pi-A and D-A type phenanthrenequinone functionalized conjugated microporous polymers (CMPs) (named DBP-TEA and DBP-TDA) for adsorption-photoreduction reclaim of gold from electronic discarded leachate. The condensed DBP-TEA and DBP-TDA demonstrate a broad visible light absorption scope, outstanding semiconductor properties and good stability. Advantaged by the excellent charge transfer efficiency of the highly conjugated D-pi-A skeleton, DBP-TEA has a narrower optical band gap of 1.50 eV compared with DBP-TDA (1.91 eV). Not surprisingly, DBP-TEA with outstanding photocatalytic activity exhibits high gold recovery capacity (3053.1 mg g-1) and fast adsorption kinetics under light condition, which is far beyond to DBP-TDA and other adsorbents that have been reported. This study introduces a novel new adsorption-photoreduction strategy for exploring efficient recovery of gold from electronic waste.