Efficient degradation of sulfadimidine via peroxymonosulfate activation by CoSe: Mechanistic insights and environmental implications

In this work, cobalt selenide (CoSe) catalysts featuring abundant reactive sites and selenium vacancies were prepared through a solvothermal route and utilized, in activating peroxymonosulfate (PMS) to degrade sulfadimidine (SMZ). The catalyst demonstrated excellent catalytic efficiency, stability, and potential for practical applications, achieving 90–100% degradation of various organic pollutants, including tetracycline, bisphenol F, and carbamazepine. Mechanistic investigations revealed that both Co and Se species worked synergistically to promote PMS activation, which was pivotal in improving the SMZ degradation efficiency. Specifically, low-valent selenium species and Se vacancies accelerated Co 2+ /Co 3+ redox transitions and facilitated ROS production, ultimately enhancing the PMS activation performance. Radical scavenging tests combined with EPR characterization confirmed that 1 O 2 was the primary reactive species involved, indicating that non-radical pathways were primarily responsible for SMZ degradation. Furthermore, quantitative structure–activity relationship (QSAR) analysis revealed that the environmental toxicity of SMZ and its main degradation products was significantly reduced after treatment. Overall, this study presents a novel and efficient PMS activator based on CoSe and elucidates its catalytic mechanism, offering new insights and technological support for the advanced treatment of antibiotic-containing wastewater.