Visible light driven photocatalytic performance of 3D TiO2/g-C3N5 nanocomposite via Z-scheme charge transfer promotion for water purification

Hierarchical 3D TiO2/g-C3N5 (T-CN) nanocomposites were synthesized for the first time to investigate its potential in environmental applications, especially water treatment. The ability of T-CN nanocomposite to degrade the quinolone-based antibiotic, ciprofloxacin (CIP) in water under visible light irradiation was compared with TiO2 and g-C3N5. In this study, 89.41 % of CIP (0.05 mM) was degraded by T-CN nanocomposite under 50 W LED irradiation for 180 mins. From the optical characterization it was clear that g-C3N5 has the ability to harness a wide range of photons from the visible region. Incorporation of g-C3N5 with TiO2 had shown efficient charge carrier generation and promoted separation of generated charge carriers more than its discrete constituents, which was confirmed from electrochemical impedance measurements. The band position alignment of TiO2 and g-C3N5constitutes Z-scheme photocatalysis, which is considered as a novel system for photocatalytic activity. The possible photocatalytic degradation mechanism of CIP was investigated from the obtained results. Finally, the growth of Staphylococcus aureus (S aureus) bacteria on the treated and untreated samples was used to further confirm the degradation of CIP solution by visible photocatalysis. This study opens a new promising material for use of degradation of antibiotics in contaminated water.