Photocatalytic degradation of norfloxacin antibiotics on Zn_xCd_(1-x)S/g-C₃N₄ composites in water

g-C₃N₄/Zn_xCd_(1-x)S composites were synthesized by a simple hydrothermal method. The composites were characterized by X-ray diffraction, UV–vis diffuse reflectance spectroscopy, infrared spectroscopy, and electron micro-projective microscopy. According to the performance of Zn_xCd_(1-x)S for the photocatalytic degradation of norfloxacin under visible light in water, the best stoichiometric number of x was 0.5. The best photolytic norfloxacin degradation rate of g-C₃N₄/Zn_xCd_(1-x)S composites was 89.8%, which was obtained when the dosage ratio of g-C₃N₄ to Zn_xCd_(1-x)S was 1:1. The experiment was conducted to investigate the effect of pH on the catalyst to obtain the optimal NORF degradation environment pH in the range of 7 ± 0.3; by simulating the anions that may be contained in the actual environmental water, the results showed that the catalyst has a certain effect on the degradation of NORF when the water contains NO₃⁻, Cl⁻ and HCO₃⁻. In addition, this study also obtained that the main active substances produced by the catalyst during degradation were electron–hole pairs by adding different trapping agents in the NORF removal experiments; and the catalyst was able to achieve a degradation rate of 86.1% after four cycles of the experiments, which proved that it had good stability.