Sustainable upcycling of copper from waste printed circuit boards with the assistance of tannic acid and Fe 3+ to a magnetic heterogeneous catalyst.

The recovery and upcycling of metals from electronic waste into functional materials for wastewater treatment is a win-win strategy for simultaneously realizing electronic waste recycling and wastewater purification. This study focused on converting Cu from waste printed boards (PCBs), a common Cu-rich electronic waste, into CuFe 2 O 4 supported on a mesoporous carbon framework (PCFT) with the assistance of Fe 3+ and tannic acid (TA). Compared to the PCF prepared without TA, the resulting PCFT exhibited excellent magnetic properties, high crystallinity, lower interfacial transfer resistance, more abundant oxygen vacancies (O V ), and lower metal leaching. Moreover, PCFT can serve as a superior heterogeneous catalyst to activate peroxymonosulfate to remove reactive brilliant blue KN-R from wastewater, and its catalytic activity was markedly higher than that of CFT synthesized with Cu(NO 3 ) 2 ·3H 2 O, which may be due to its higher specific surface area and more abundant O V . The combined results of scavenging experiments, electron paramagnetic resonance analysis, and electrochemical measurements implied that both radical and nonradical processes promoted the elimination of KN-R; however, • OH and SO 4 •- were not the major contributors. Furthermore, the PCFT exhibited high adaptability to pH and water matrices, confirming its practical application potential. These findings provide a novel strategy for the upcycling of metals from electronic waste.