Ag/Ag2O/g-C3N4/BiVO4复合光催化体系降解盐酸四环素机理研究

为提高钒酸铋(BiVO₄)对盐酸四环素(TC-HCl)在水溶液中的降解效率，以银基材料(Ag/Ag₂O)和石墨相氮化碳(g-C₃N₄)共同改性BiVO₄，通过水热法、煅烧法、湿浸渍法、沉淀和热分解法分步制备了Ag/Ag₂O/g-C₃N₄/BiVO₄四元复合材料；采用X-射线衍射(XRD)、扫描电子显微镜(SEM)、X-射线光电子能谱(XPS)及紫外-可见漫反射光谱法(UV-vis DRS)等方法对复合材料的形貌结构、元素分布及光学性质进行了表征. 结果表明:①沉积了Ag/Ag₂O粒子后，复合材料对TC-HCl的吸附能力显著提高. ②纳米Ag粒子的表面等离子体共振效应(SPR)以及g-C₃N₄的协同作用拓宽了光响应范围，表现出更好的光催化性能. ③相较于BiVO₄、g-C₃N₄及g-C₃N₄/BiVO₄，该复合材料对TC-HCl的降解效果最佳，降解率可达89.19%，且经过4次循环使用后仍能保持74.8%的降解率. ④UV-vis及XPS分析证明，该复合材料的可见光响应拓展至548 nm，可吸收更多可见光. ⑤体系自由基捕获试验证明，·O₂-和h+在光催化降解TC-HCl过程中发挥主要作用，且h+的作用大于·O₂-. 研究显示，Ag/Ag₂O/g-C₃N₄/BiVO₄是一种高效稳定的复合光催化剂，其在处理TC-HCl抗生素废水方面具有潜在的应用前景. 

Mechanism Study on Degradation of Tetracycline Hydrochloride by Ag/Ag2O/g-C3N4/BiVO4 Composite Photocatalytic System

In order to improve the degradation efficiency of bismuth vanadate (BiVO₄) on tetracycline hydrochloride (TC-HCl) in aqueous solution, silver-based material (Ag/Ag₂O) and graphitic phase carbon nitride (g-C₃N₄) were used to co-modify BiVO₄, and the Ag/Ag₂O/g-C₃N₄/BiVO₄ quaternary composites were constructed by hydrothermal, calcination, wet impregnation, precipitation and thermal decomposition methods in a stepwise manner. The composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Ultraviolet-visible diffuse reflectance spectrometry (UV-vis DRS) for their morphological structure, elemental distribution and optical properties. The experimental results showed that: (1) The deposition of Ag/Ag₂O particles significantly increased the adsorption capacity of the material for TC-HCl. (2) The surface plasmon resonance effect (SPR) of Ag nanoparticles and the synergistic effect of g-C₃N₄ broadened the photoresponse range and improved the photocatalytic performance. (3) Compared with BiVO₄, g-C₃N₄ and g-C₃N₄/BiVO₄, the composite had the best degradation effect on TC-HCl, with the degradation rate up to 89.19%, and the degradation efficiency was still 74.8% after four cycles. (4) UV-vis and XPS analysis determined that the visible light response of the composite extended to 548 nm and could absorb more visible light. (5) The system radical trapping test demonstrated that ·O₂- and h+ played a major role in the photocatalytic degradation of TC-HCl, and the role of h+ was greater than that of ·O₂-. The above results show that Ag/Ag₂O/g-C₃N₄/BiVO₄ is an efficient and stable composite photocatalyst with potential application in the treatment of TC-HCl antibiotic wastewater.