One-pot hydrothermal preparation of rich-oxygen vacant Bi2SiO5/CuBi2O4 Z-Scheme heterojunction for visible light-driven photocatalytic removal of antibiotic-resistant bacteria

Bi2SiO5/CuBi2O4 Z-Scheme heterojunction enriched with oxygen vacancies were prepared by a simple one-pot hydrothermal method. The photocatalytic activity of Bi2SiO5/CuBi2O4 nanocomposites was evaluated under visible light irradiation using tetracycline, antibiotic-resistant Escherichia coli (AR E. coli), and tetracycline-resistant genes as the target pollutants. The results showed that Bi2SiO5/CuBi2O4 nanocomposites had the best photocatalytic activity, which could degrade 83.3 % of tetracycline within 2 h, completely inactivate AR E. coli within 2.5 h, and almost completely destroy tetracycline-resistant genes within 3 h. In addition, the scavenging experiments and ESR experiments not only showed that the active substances of O2-, h+ and OH played a dominant role and 1O2 played a secondary role in the photocatalytic system of Bi2SiO5/CuBi2O4 nanocomposites, but also confirmed that the Z-Scheme heterojunction was successfully constructed between Bi2SiO5 and CuBi2O4. Oxygen vacancies were detected by EPR experiments. The formation of oxygen vacancies and Z-Scheme heterojunction enhanced the light absorption properties of the Bi2SiO5/CuBi2O4 nanocomposites and improved the separation efficiency of the photogenerated electron-hole pairs compared to the single Bi2SiO5 and CuBi2O4 materials. This work showed that Bi2SiO5/CuBi2O4 was a new and efficient photocatalyst for the removal of tetracycline, AR E. coli and tetracycline-resistant genes, which provided a feasible idea for the management of water environment pollution.