Enhanced Photocatalytic Degradation of Antibiotics by Ag/BiOI/g-C3N4 Composites

As an efficient, safe, and environmentally friendly technology, semiconductor photocatalysis has been widely used in the removal of antibiotics from wastewater. In this work, a novel Ag/BiOI/g-C 3 N 4 composite photocatalytic material, BiOI/g-C 3 N 4 , g-C 3 N 4 , and BiOI are prepared as the photocatalysts. The morphologies, chemical properties, and photocatalytic performances of the photocatalysts are characterized using scanning electron microscope, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier-transform infrared spectrometer, ultraviolet–visible spectroscopy (UV–Vis) diffuse reflectance spectra, and photoluminescence spectra. In addition, tetracycline hydrochloride (TC) and ceftiofur sodium aqueous solutions are used to simulate wastewater and the photocatalytic degradation performances of the photocatalysts are investigated and compared under visible light. Compared to g-C 3 N 4 , BiOI, and BiOI/g-C 3 N 4 , the Ag/BiOI/g-C 3 N 4 demonstrates superior performance, increasing the removal rates of TC and ceftiofur sodium to 85.6% and 90.2%, respectively. The photocatalytic mechanism of the Ag/BiOI/g-C 3 N 4 may involve the promotion of the visible light–harvesting ability and inhibition of the recombination of photogenerated electron/hole pairs. Furthermore, the primary active groups in the system are identified as superoxide radicals (·O 2 − ) and hydroxyl radicals (·OH). Herein, some valuable insights into the development of innovative photocatalytic materials are offered for the effective removal of antibiotics from water.