Photocatalytic degradation of levofloxacin by a novel Sm6WO12/g-C3N4 heterojunction: Performance, mechanism and degradation pathways

Recent year pharmaceutical pollutants have highly detected in environment, because they do not completely mineralized and remain toxic. Semiconductor photocatalyst materials have well recognized as promising technology for environmental pollutants removal in the presence of visible light. In this work, a novel binary Sm6WO12 modified g-C3N4 nanosheets heterojunction was fabricated via simple facile method. The morphology of the newly prepared g-C3N4 and Sm6WO12 was confirmed as nanosheets and nanorods by using microscopy techniques. The sequence of characterization results verified that the Sm6WO12/g-C3N4 synergistically integrate the excellent properties and successful construction of hetero-structure between the Sm6WO12 and g-C3N4. The Sm6WO12/g-C3N4 nanocomposite heterojunction catalyst shows higher photocatalytic efficiency towards degrading pharmaceutical pollutant levofloxacin compared to individual g-C3N4 and Sm6WO12 photocatalyst. The results indicate that about 90.8% of levofloxacin was degraded after 70 min in the presence of Sm6WO12/g-C3N4 nanocomposite. Through radical trapping experiments, O-2(center dot-) and (OH)-O-center dot were proved to be the leading reactive oxidative species contributing to degradation of levofloxacin. Possible photodegradation pathways were proposed based on the detected intermediate products and transformation products. Furthermore, the synthesized Sm6WO12/g-C3N4 heterojunction demonstrated excellent reusability and stability without of loss of photo catalytic activity. Favorably, this study might provide a deep insight into mechanism and possible degradation pathways of levofloxacin by Sm6WO12 modified g-C3N4 heterojunction photocatalyst.