Enhanced photodegradation of sulfamethoxazole by a novel WO₃-CNT composite under visible light irradiation

As one of the emerging environmental issues, the existence of antibiotics in the water bodies is believed to pose threat to not only the environment but also human health. Recently, semiconductor-based photocatalysis has drawn wide attention since it shows great potential in removal of organic pollutants as well as other emerging organic contaminants from aquatic systems. Therefore, in this study, efforts were devoted to fabrication of novel visible light driven heterogeneous photocatalysts to explore their possible applications in photodegradation of antibiotics. Particularly, multi-walled carbon nanotubes (MWCNTs) was selected as co-catalyst to WO_3, and three WO₃-MWCNTs (WO₃-CNT) composites were prepared as photocatalysts, namely WT-2, WT-4 and WT-8. The physical and chemical properties of these obtained WO₃-CNT composites were thoroughly characterized by different methods. Simultaneously, sulfamethoxazole (SMX), one of the most widely used antibiotics was chosen as the target pollutant to evaluate the photocatalytic performance of the WO₃-CNT composites. The degradation intermediates were analyzed by LC/MS/MS, and subsequently a possible degradation mechanism was proposed. Compared to bare WO₃, all three WO₃-CNT composites showed notably enhanced photocatalytic activity, demonstrating that they have the potential to be used as effective photocatalysts to degrade sulfonamide class of antibiotics.