Sulfurization-derived Fe3S4 in copper tailings as a peroxymonosulfate activator for efficient salicylhydroxamic acid degradation

In this work, sulfidation modification of copper tailings (CT) yields a cost-effective catalyst (S-CT) for peroxymonosulfate (PMS) activation. In situ-grown sulfur vacancy (S V )-rich Fe 3 S 4 nanoparticles on S-CT surface plays a pivotal role, elevating the degradation kinetic constant ( k obs ) of salicylhydroxamic acid (SHA) in the S-CT/PMS system to 40-fold that of the CT/PMS system (0.1641 min −1 vs. 0.0041 min −1 ). The synergistic radical/non-radical pathways involving surface-bound •OH (•OH surface ), 1 O 2 and Fe IV O preferentially attack the hydroxamic acid group (-CONHOH) of SHA, achieving its complete degradation. Notably, S V narrows the p-d band gap of Fe 3 S 4 , significantly strengthening the electron transfer between Fe and S sites while enhancing the adsorption-activation of PMS. Therefore, S-CT exhibits more remarkable catalytic performance compared to other solid waste-derived catalysts previously developed by our group. In summary, this study provides an innovative and practical strategy for developing environmental remediation materials from copper tailings, showcasing its promising potential in organic wastewater treatment.