Visible Light-Driven Photocatalytic Degradation of Tetracycline Using p-n Heterostructured Cr₂O₃/ZrO₂ Nanocomposite

Abstract

Antibiotic pollution beyond the safety limits poses a significant threat to the environmental sustainability and human health which necessitates the development of efficient methods for reducing antibiotics in pharmaceutical wastewater. Photocatalysis is a proven technology which has drawn considerable attention in semiconductor photocatalysts. Our study aims to develop a highly efficient Cr2O3/ZrO2 photocatalyst for the degradation of tetracycline (TCL) under visible light. The synthesized catalyst was well characterized by XRD, HR-TEM-SAED, XPS, FT-IR, BET and UV-Vis-DRS methods. The effects of various parameters on photocatalytic degradation were evaluated in detail, showing that 97.1% of 50 mgL−1 tetracycline concentrations could be degraded within 120 min at pH 5 with a 0.1 gL−1 photocatalyst-loading concentration under visible light (300 W Xe lamp). The uniform distribution of spherical ZrO2 nanoparticles on the surface of the Cr2O3 nano-cubes efficiently reduced the recombination rate with an energy bandgap of 2.75 eV, which provided a faster photodegradation of tetracycline under visible light. In addition, a plausible degradation pathway and photoproducts generated during the photocatalytic degradation of TCL are proposed based on the LC-ESI/MS results, which suggested that efficient photodegradation was achieved during the visible light irradiation. Thus, our study reveals that the cost-effective Cr2O3-based photocatalyst with multi-reusability and efficient energy consumption could be an efficient photocatalyst for the rapid degradation of TCL during the wastewater treatment process.

Keywords

• Cr₂O₃/ZrO₂
• visible light
• tetracycline
• degradation
• photocatalysis