Solar photocatalytic CeO2/g-C3N4 removal of micropollutants in the water environment through the generation of singlet oxygen

The synthesis of photocatalysts with good photocatalytic performance to selectively oxidize micropollutants in complex water environments has received widespread attention. This study successfully synthesized a CeO2/g-C3N4 composite, which could degrade sulfamethoxazole (SMX) up to 95 % under simulated sunlight (SSL) in 60 min. Additionally, it exhibited favorable selective oxidation characteristics in complex water environments. EPR and radical scavenging experiments proved the main oxidation contributions of singlet oxygen (1O2) in the system. Photoluminescence spectroscopy demonstrated that the composite material could generate more triplet excitons to generate 1O2 with ground-state oxygen (3O2) through an energy transfer pathway. The product analysis of the two models of micropollutants, SMX and carbamazepine, indicated an overall rise in the biodegradability of the majority of intermediates, accompanied by a decrease in acute toxicity. The composite showed high stability even after 5 cycles. Various micropollutants have degradation of varying degrees in different natural water matrices. In summary, this study introduced a novel photocatalytic oxidation strategy with selective oxidation capability, providing possibilities for practical applications and environmentally friendly photocatalytic processes.