Facile synthesis of Z-scheme composite of TiO2 nanorodig-C3N4 nanosheet efficient for photocatalytic degradation of ciprofloxacin

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 mu mol 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 mu mol 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 center dot 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. (C) 2020 Elsevier Ltd. All rights reserved.