Facile synthesis of copper tungstate (CuWO4) for novel photocatalytic degradation of tetracycline under visible light

Abstract

In this study, CuWO4 materials were synthesized via facile hydrothermal and heat treatment. The physicochemical properties of the synthesized materials were well analyzed by advanced characterization methods such as SEM, XRD, FT-IR and UV–Vis. Photocatalytic performance of these synthesized CuWO4 materials were investigated via degradation of tetracycline (TC) under excitation of visible light, which was generated from a 32 W compact lamp. The material calcined at 500 °C contained only triclinic CuWO4 phase. At low calcination temperature lower than 500 °C, WO3 and CuWO4·2H2O remained in the synthesized materials while CuO and Cu2O newly occurred when the material was calcined at 600 °C. The occurrence of impurities phases significantly decreased photocatalytic activity of the synthesized material. The synthesized CuWO4-500, which was calcined at 500 °C, exhibited high visible light absorption capacity with band-gap energy (Eg) of approximately 2.13 eV. The CuWO4-500 sample also exhibited great photocatalytic ability for decomposition of TC even under excitation of provided visible light. The study also investigated that pH 6 was optimal pH for TC degradation by the synthesized CuWO4. Under optimized pH (pH 6), the synthesized CuWO4 photocatalytically degraded over 60% TC after 2 h being irradiated by visible light.