Efficient adsorption and photocatalytic degradation of pharmaceutical compounds by Bi24O31Br10: Mechanism, toxicity assessment, and degradation pathways

This study synthesized Bi 24 O 31 Br 10 (BOB) to enhance the photocatalytic degradation of four common pharmaceutical compounds including ofloxacin (OFL), sulfamethoxazole (SMX), favipiravir (FAV) and ibuprofen (IBP). Characterization results demonstrated that BOB exhibited superior photocatalytic properties, including an extensive specific surface area, an optimal band gap and the presence of surface defects. Photocatalytic degradation experiments showed that BOB exhibited substantial adsorption capacity and photocatalytic efficiency for all four pharmaceuticals. Specifically, OFL, IBP, and FAV were removed by >95.5 % within 2 h, and SMX was removed by 57 % (10 mg L −1 pharmaceuticals/100 mg L −1 BOB). The adsorption was facilitated by Brönsted acid sites associated with oxygen vacancies and Lewis acid Bi sites. The degradation mechanism primarily involved key reactive species, including ·O 2 − , ·OH and h + . The degradation pathways for four pharmaceuticals were elucidated, as well as the biotoxicity of the products, which confirmed the alleviating potential of BOB-driven photocatalytic degradation on pharmaceuticals. These findings highlight the future potential of BOB-driven photocatalysis in mitigating pharmaceutical pollution in aquatic environments.