Efficient degradation of oxytetracycline by glucose modified CuFeO2 in visible-light-assisted heterogeneous activation of peroxymonosulfate system:Performance, mechanism and DFT calculation

Visible-light-assisted heterogeneous activation of peroxymonosulfate (PMS) exhibits great potential in refractory wastewater treatment. Efficient and environmental-friendly heterogeneous catalysts are the key to drive sus-tainable development of the process. Herein, the glucose modified CuFeO2 (Glu/CFO) catalysts were synthesized to activate PMS and degrade oxytetracycline (OTC). The modification of glucose introduced more active func-tional groups on the Glu/CFO surface, the narrowed band gap and increased photogenerated electrons transfer of CuFeO2. The Glu/CFO with 0.5 g glucose possessed more superior catalytic performance than other as-prepared samples. Furthermore, the Glu/CFO-0.5 showed superior reuse performance and high material stability under long-term operation. Significantly, the photogenerated electrons effectively promoted the in-situ cycle of ---Fe3+ and ---Cu2+ to ---Fe2+ and ---Cu+ on the surface of Glu/CFO-0.5, accelerating the generation of reactive oxygen species (ROSs) and OTC degradation. The results of free radical quenching experiment and ESR demonstrated that the non-free radical pathway dominated by 1O2 was the main way of OTC degradation. Combining XPS spectra, the degradation mechanism of OTC in Vis/PMS/Glu/CFO-0.5 system was elucidated. Based on HPLC-MS analysis and DFT calculation, the possible degradation pathways of OTC were explored in depth, and the toxicity of the corresponding products was analyzed based on quantitative structure-activity relationship predictions.