Upcycled nickel-cobalt-manganese catalysts from spent lithium-ion batteries for efficient peroxymonosulfate activation and sulfamethoxazole degradation

With the large-scale disposal of spent lithium-ion batteries (SLIBs) and the ongoing accumulation of organic pollutants in water bodies, the resource recovery of solid waste and water pollution control have emerged as critical challenges in the environmental field. To address the dual challenges of SLIBs and persistent organic pollutants, a nickel‑cobalt‑manganese oxide catalyst (NCM-APS) was synthesized via hydrothermal treatment of SLIB leachate with ammonium persulfate (APS) for peroxymonosulfate (PMS) activation. The catalyst featured a nanostructured morphology, large surface area, and abundant hydroxyl groups, enabling efficient PMS activation. Under optimized conditions, nearly complete removal of 10 μmol/L sulfamethoxazole (SMX) was achieved within 20 min, and 82.4% removal of 50 μmol/L SMX occurred within 1 h. The catalyst exhibited favorable stability to a certain extent, maintaining activity in the presence of common coexisting ions (Cl − , NO 3 − , SO 4 2− ) and after repeated cycles. Reactive species analysis suggested the generation of SO 4 • − ${\mathrm{SO}}_4^{•-}$ , HO • ${\mathrm{HO}}^{•}$ , 1 O 2 , and O 2 • − ${\mathrm{O}}_2^{•-}$ , with 1 O 2 as the predominant oxidant. High-resolution mass spectrometry and Fukui function analysis elucidated the SMX degradation pathway. This work demonstrates a sustainable strategy for SLIB upcycling and highlights the practical potential of PMS-based advanced oxidation processes in wastewater treatment.