[Preparation of pg-CN/BiOBr/Ag Composite and Photocatalytic Degradation of Sulfamethoxazole].

A pg-CN/BiOBr/Ag composite was successfully prepared by simple high-temperature calcination and co-precipitation methods. The composite was characterized by means of XRD, SEM, TEM, XPS, UV-Vis, BET, and photocurrent analyses alongside other detection methods, and the degradation of 10 mg·L sulfamethoxazole was investigated under simulated visible light irradiation. The results showed that the pg-CN/BiOBr/Ag composite had the best degradation effect on sulfamethoxazole when the loading ratio of silver was 5%. Compared with pg-CN, BiOBr monomer, and pg-CN/BiOBr composite, the photocatalytic degradation effect of the pg-CN/BiOBr/Ag (5%) was significantly improved, and the degradation rate was almost 100% within 30 min. The reaction rate constant (0.21016 min) was 13.15 times that of pg-CN/BiOBr. Through radical quenching experiments, it was shown that the main active substances in the photocatalytic degradation were holes (h), superoxide radicals (·O), and singlet oxygen (O), among which superoxide radicals (·O) contributed the most. Cyclic tests of pg-CN/BiOBr/Ag showed that the synthesized material has good recyclability and application prospects.