Effective H2O2-Free photo-Fenton processes over ZnSe nanosheets for photocatalytic degradation of dyes and antibiotics

Abstract

BackgroundTraditional Fenton process depends on adding additional H2O2, which is mainly produced by anthraquinone process involving large amounts of harmful organic solvents and H2, making a secondary pollution. In-situ photocatalytic generation of H2O2 for Fenton-degradation is a promising way to remove pollutants. MethodsZnSe nanosheets was obtained via a simple one-step solvothermal method using diethylenetriamine, hydrazine hydrate and water as reaction medium. Significant FindingsZnSe tends to produce H2O2 under 300 W Xenon light irradiation, which then participates in Fenton reaction with the assistance of Fe2+ to generate active hydroxyl radical for degradation of dyes and antibiotics, leading to the photocatalytic H2O2 evolution rate decreases from 241 μmol·L − 1·h − 1 in pure water to 190 μmol·L − 1·h − 1 in Fe2+-contained solution. The photo-Fenton degradation rate of Methylene blue (MB), Tetracycline hydrochloride (TCH), Ciprofloxacin (CIP) is better than those of corresponding photocatalytic process and Fenton process alone, this is mainly attributed to the continuous generation and activation of H2O2 in the presence of ZnSe and Fe2+based on a series of trapping experiments and related analysis. Besides, ZnSe also displays excellent stability and hydrophilicity in Fe2+-contained solution, which is benefit to the contact of catalyst and pollutants. Further investigation shows the kinetic of photo-Fenton degradation over ZnSe follows the pseudo-first-order kinetic.