Abstract: The large-scale use of antibiotics makes them ubiquitous in the water environment, which poses a certain threat to the ecological environment and human health. Bismuth oxychloride (BiOX (X=Cl, Br, I)) can be used as a photocatalyst to degrade residual antibiotics in water due to its unique two-dimensional layered structure and suitable bandgap. However, BiOX (X=Cl, Br, I) has problems including weak visible light absorption capacity and poor stability, which often requires composite modification (such as metal loading, carbon material modification, and construction of heterojunctions) to improve their performance for removing antibiotics in water. This paper mainly introduces the design, synthesis, mechanism of activity enhancement and photocatalytic reaction mechanisms of BiOX (X=Cl, Br, I) composite photocatalysts for the degradation of antibiotics in water. Compared with metal loading and carbon material modification, the construction of semiconductor heterojunction is a common and cost-effective method to enhance the performance of BiOX (X=Cl, Br, I) photocatalytic degradation of antibiotics in water. It is pointed out that the future research in this field need to evaluate the performance of BiOX (X=Cl, Br, I) composite photocatalytic materials by degrading the different types of antibiotics in water, and it is also necessary to reveal the effect of the background components of natural water bodies (such as dissolved organic matter, inorganic ions, etc.) on the removal of antibiotics using BiOX (X=Cl, Br, I) composite photocatalysts. Finally, it is proposed to introduce peroxide to enhance the effect of BiOX composite photocatalytic system to mineralize antibiotics in water and constructing the magnetic BiOX photocatalytic materials could solve the problem of solid-liquid separation after degradation reaction.

Key words: Bismuth oxychloride, Catalyst, Antibiotics, Degradation, Reaction mechanism