Harnessing synergistic effects of UV/MgO2/PMS system for enhanced antibiotic degradation

In recent years, transition metal oxide and photocatalysts have garnered significant attention for their role in photo-induced persulfate (PMS) activation systems. However, the exploration of MgO2-based UV/PMS systems has been notably absent. This study introduces a novel perspective on the effectiveness of the UV/MgO2/PMS oxidation-photocatalysis system for degrading sulfamethoxazole (SMT), driven by its unique lamellar stacked flower-like microsphere and the synergistic interplay within its subsystems. Remarkably, the degradation rate constant (kobs) of the UV/MgO2/PMS system significantly surpasses 11.8 and 21.7 times that of both the singular UV/MgO2 and the MgO2/PMS systems, respectively. Three primary reaction pathways are systematically delineated within the UV/MgO2/PMS framework, which are PMS activation, photocatalysis of MgO2, H2O2 release from MgO2. By harnessing the differential capacities for reactive radical production among these pathways, we potentially demonstrated the existence of mutual synergy among the three pathways, namely that the photo-generated charge carriers produced by UV excitation of MgO2 can promote the production of more reactive radicals (RSs) in the subsystems. And this interconnectivity's role can enhance the system's resistance to interference, which is due to the large amount of 1O2 in the system. This work offers fresh insights into the activation mechanism of transition metal oxide systems integrated with UV/PMS, laying a theoretical foundation for the future exploration and elucidation of other complex systems.