Facile synthesis of Z-scheme composite of TiO2 nanorod/g-C3N4 nanosheet efficient for photocatalytic degradation of ciprofloxacin

Abstract

Developing efficient and robust photocatalyst is crucial for antibiotic degradation in water treatment. In this study, the Z-scheme nanocomposite of 1D/2D TiO2 nanorod/g-C3N4 nanosheet was successfully fabricated for the efficient photocatalytic degradation of ciprofloxacin (CIP). 93.4% degradation of CIP was achieved in 60 min under the conditions of the nanocomposite containing 30 wt% g-C3N4, 15 μmol L−1 CIP and pH of 6.3. The effect of catalysts, CIP concentrations and pH on degradation were systemically studied. It was found that the photodegradation process fitted the pseudo-first-order kinetic model well when CIP concentration was higher than 10 μmol L−1. Under simulated sunlight irradiation, the nanocomposite exhibited 2.3 and 7.5-times CIP photodegradation rate than those of commercial TiO2 powder and g-C3N4 nanosheet, respectively. Besides, degradation kinetics and mechanisms were further investigated. Scavenging experiments and electron spin resonance (ESR) technique confirmed that h+ and ·OH played a major role in the CIP degradation process. Three CIP degradation pathways were subsequently proposed. This work may provide an effective strategy to remove various antibiotics in water treatment.