Organic Synthesis of CuO/g-C3N4 and Photocatalytic Degradation of Tetracycline

To degrade high concentration tetracycline (TET), composite materials CuO/g-C₃N₄ (CuOCN) were prepared using an organic synthesis method to investigate their degradation effect on TET under visible light. The materials were characterized through X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), UV-visible diffuse reflectance spectrometer (DRS), and X-ray photoelectron spectroscopy (XPS). The toxicity of the degradation products of nhnnnTET was assessed through antibacterial experiments, and the degradation mechanism of TET was studied using quenching agent capture and High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS). XRD results confirmed the formation of CuOCN. Photocatalytic experiments demonstrated that CuOCN2 exhibited a relatively effective degradation of TET and could be reused multiple times, with a degradation rate constant value of 0.0095 min^–1. TEM results revealed a layered structure of both CuO and C₃N₄, which were found to be attached together. High-Resolution TEM (HRTEM) showed the combination of the two components in CuOCN2, with CuO displaying two crystal planes. X-ray Energy Dispersive Spectrum (EDS) analysis indicated that the mass fraction of CuO in CuOCN2 was approximately 15%. DRS analysis revealed that the addition of CuO widened the visible light absorption range of the composite materials and reduced the bandgap width. The band gaps of CuOCN1, CuOCN2, and CuOCN3 were 2.45, 2.66, and 2.76 eV, respectively. Photocurrent and photoresistance tests demonstrated the good photoelectric effect of CuOCN2. XPS analysis confirmed that the CuOCN2 composite material possessed the chemical composition and structure both CuO and C₃N₄. During the catalytic degradation of TET, four active substances were generated, reducing the toxicity of the degradation products. HPLC-MS analysis revealed that TET underwent reactions such as cracking and cross-linking during degradation, leading to reduced toxicity. This study provides an experimental basis for the degradation of high concentration TET by CuOCN2.