Light-Promoted Efficient Gold Recovery Enabled by a Polydopamine-Functionalized Covalent Organic Framework

The rapid proliferation of artificial intelligence (AI) and information technologies is driving a sharp increase in global electronic waste, creating an urgent demand for recovering precious metals like gold from secondary resources to achieve environmental and economic benefits. Herein, a polydopamine (PDA)-functionalized β-ketoenamine-linked covalent organic framework composite, denoted as TATP/PDA, is designed in combination with a light-assisted strategy for efficient gold recovery. Benefiting from the synergistic effects of hydrogen bonding and π-π interactions between PDA and the TATP COF, which enhance photoelectric activity and provide abundant adsorption sites, the TATP/PDA exhibits an exceptional adsorption capacity of 5220 mg·g^-1, ultrafast adsorption kinetics (>99% removal efficiency within 30 s), and remarkable selectivity in complex matrices. Experimental characterizations disclose that the engineered abundant nitrogen and oxygen active sites, along with the inherent photocatalytic reduction capability, significantly enhance the gold adsorption performance. These key merits position TATP/PDA as one of the best-performing materials in terms of overall performance. In practical application, TATP/PDA exhibits exceptional performance in recovering gold from real e-waste leachate. Moreover, the recovered gold-loaded composite serves as a sustainable photocatalyst for hydrogen evolution. This dual-benefit strategy not only promotes resource recycling but also contributes to the goals of a green and circular economy.