Enhanced photocatalytic performance of ZnO/Bi2WO6 heterojunctions toward photodegradation of fluoroquinolone-based antibiotics in wastewater

Abstract

The present work focused on development of a new ZnO/Bi2WO6 heterojunction photocatalyst with a high solar-light-responsive property and a promising charge carriers separation efficiency. A facile solvothermal route for preparation of novel ZnO/Bi2WO6 heterojunction based on well dispersion of flower-like Bi2WO6 on the surface of rod-like ZnO has been demonstrated. The prepared photocatalyst exhibited the orthorhombic phase of Bi2WO6 (BWO) together with the hexagonal phase of ZnO. The 0.05ZnO/BWO heterojunction photocatalyst with the smallest size and lowest PL intensity, implying highest electron-hole separation efficiency, exhibited the highest photoactivity of 87%, 85%, and 84%, respectively, toward degradation of NOR, CIP, and OFL antibiotics. The photocatalyst also provided a very high solar-light-driven photodegradation performance of 97% toward degradation of NOR antibiotic for 120 min. The generation of the ZnO/Bi2WO6 heterostructures is the key factor for an enhanced photocatalytic performance in the resultant photocatalyst. The photodegradation of the fluoroquinolone antibiotics followed the first-order reaction. Photogenerated hole plays an important role in removal of NOR antibiotic. The chemical structure of the 0.05ZnO/BWO heterojunction photocatalyst remained stable after photodegradation. The prepared photocatalyst still shows high efficiency after the fifth run implying its promising structural stability and reusability. This work demonstrates a very high potential of the prepared heterojunction 0.05ZnO/BWO photocatalyst for detoxification of fluoroquinolone-based antibiotics in wastewater.