Facile fabrication of AgVO3/rGO/BiVO4 hetero junction for efficient degradation and detoxification of norfloxacin

In the recent past, the development of efficient materials for degradation and detoxification of antibiotics has gained more attention in wastewater treatment process. As a visible light active material AgVO3 has attracted much concern in environmental remediation. To improve its efficiency and stability, a novel heterojunction was prepared by combining AgVO3 with rGO and BiVO4 through a hydrothermal method. The prepared AgVO3/rGO/BiVO4 composite was further utilized for effective detoxification of Norfloxacin (NFC) antibiotic. The morphological analysis revealed the clear rod shaped AgVO3 and leaf like BiVO4 that are evenly distributed on reduced graphene oxide (rGO) layers. The visible light absorbance and the catalytic activity of AgVO3/rGO/BiVO4 was dramatically improved compared to pure AgVO3 and BiVO4. From the results it showed that the degradation efficiency of AgVO3/rGO/BiVO4 (∼96.1%, k = 0.01782 min-1) was 2.5 times higher than pure AgVO3 and 3.4 times higher than the pure BiVO4 respectively towards NFC after 90 min. The higher efficiency could be attributed to the heterojunction formation and faster charge separation. The radical trapping experiments results indicated that the •OH, and O2•- are the main species responsible for degradation. The degradation products of NFC were analysed through ESI-LC/MS and pathway was proposed. Furthermore, the toxicity assessment of pure NFC and its degradation products was studied using E. coli as the model bacteria through colony forming unit assay and the results indicated the efficient detoxification was attained during the degradation process. Thus, our study provides new insight into detoxification of antibiotics using AgVO3 based composites.