Copper in LaMnO to promote peroxymonosulfate activation by regulating the reactive oxygen species in sulfamethoxazole degradation.

Perovskites with flexible texture structures and excellent catalytic properties have attracted considerable attention in peroxymonosulfate (PMS) activation for addressing organic contaminants in water. In this study, the role of copper to promote PMS activation performance of LaMnO was investigated. 100% sulfamethoxazole (SMX) degradation and 34% mineralization were achieved over copper doped LaMnO while only 60% SMX was removed without TOC removal by LaMnO. Especially, compared with LaMnO, the pseudo-first-order reaction rate constant was increased by 8.30 times when the atomic ratio of Cu/Mn was 1:3. It proved that only O was generated in LaMnO while O, especially •OH and SO• were all detected in Cu-LaMnO/PMS system. The characterization results showed that Cu induced the formation of LaMnO and LaCuO heterostructure with enhanced content of relatively low-valence Mn and Cu and abundant oxygen vacancies (OVs). Hence, the efficient PMS activation by Cu-LaMnO was due to regulating the produced reactive oxygen species (ROS). A radical dominant instead of O involved PMS activation mechanism over LaMnO-LaCuO was proposed for efficient degradation of SMX. Finally, the possible degradation pathways of SMX were discussed based on HPLC-MS analysis. This study provided a new insight of improving the catalytic activity of perovskites in PMS activation in water treatment.