Efficient photo-Fenton-like catalytic system based on TiO2 hollow microspheres/g-C3N4 and peroxymonosulfate oxidation for tetracycline degradation

This study addresses the issue of antibiotic pollution in water bodies, using tetracycline (TC) as a model pollutant. A novel photocatalyst, THM/CN (TCN), composed of TiO2 hollow microspheres (THM) and g-C3N4 (CN) nanosheets, was successfully developed and combined with peroxymonosulfate (PMS) oxidation to form a highly efficient photo-Fenton-like catalytic system. Under optimal conditions, the highest catalytic activity was experienced for the catalyst with the THM loading 10 % (10-THM/CN), and 96.97 % TC degradation was achieved within 30 min in the TCN/PMS photo-Fenton-like system. The synergy between THM and CN frameworks has been shown to significantly outperform pure photocatalysis and heterogeneous Fenton-like reactions. In-depth quenching experiments and electron paramagnetic resonance (EPR) analyses confirmed the involvement of the coexistence and relative contributions of multiple reactive oxygen species (ROS) in the degradation process. The study proposes a charge transfer mechanism based on the S-scheme heterojunction, which enhances photocatalytic activity through efficient carrier separation and strong redox ability. This work presents a promising, environmentally friendly technology for antibiotic pollution treatment.