Silver-Based Composite Photocatalytic Materials and Their Visible-Light-Driven Degradation of Tetracycline Hydrochloride in Aqueous Solutions

This study fabricated a silver-based composite photocatalytic material (Ag/AgVO3/g-C3N4) for antibiotic degradation driven by visible light. The composite was prepared using the water bath method, and its morphology, structure and optical properties were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and Ultraviolet-Visible (UV-vis) diffuse reflection spectroscopy. The photocatalytic activity of the composite was evaluated within 240 min under visible-light irradiation, and its degradation effect was quantified using tetracycline hydrochloride as the target pollutant, applying different conditions of composite proportions and dosage, initial concentration of the contaminant, and pH. The experimental results demonstrated that the composite doped with Ag+ had a higher degradation effect on tetracycline hydrochloride. The highest degradation rate of tetracycline hydrochloride (reaching 86.64%) was achieved at a composite ratio of Ag/AgVO3/5g-C3N4, dosage of 0.8 g·L−1, and initial concentration of tetracycline hydrochloride of 10mg·L−1. This rate is approximately 1.4 times and 1.7 times those of the pure-phase g-C3N4 and AgVO3, and the degradation rate remains stable at 81.52% after 4 cycles of experiments. The favorable stability of the photocatalyst was also verified through a stability test.