Interfacial Coordinational Bond Triggered Photoreduction Membrane for Continuous Light-Driven Precious Metals Recovery

Abstract

Chemical/electric energy-driven processes dominate the traditional precious metal (PM) recovery market. The renewable energy-driven selective PM recycling approach crucial for carbon neutrality is under exploration. Herein, via an interfacial structure engineering approach, coordinational-active pyridine groups are covalently integrated onto the photoactive semiconductor SnS 2 surface to construct Py-SnS 2 . Triggered by the preferred coordinational binding force between PMs and pyridine groups, together with the photoreduction capability of SnS 2, Py-SnS 2 shows significantly enhanced selective PM-capturing performance toward Au 3+, Pd 4+, and Pt 4+ with recycling capacity up to 1769.84, 1103.72, and 617.61 mg/g for Au 3+, Pd 4+, and Pt 4+, respectively. Further integrating the Py-SnS 2 membrane into a homemade light-driven flow cell, 96.3% recovery efficiency was achieved for continuous Au recycling from a computer processing unit (CPU) leachate. This study reported a novel strategy to fabricate coordinational bonds triggered photoreductive membranes for continuous PM recovery, which could be expanded to other photocatalysts for broad environmental applications.