BiVO_4联合H_2O_2或K_2S_2O_8光催化降解布洛芬

Photocatalytic degradation of ibuprofen via BiVO_4 combined with H_2O_2 or K_2S_2O_8

以水热法制备了BiVO_4光催化剂,并用X射线衍射和扫描电镜对其进行表征。在模拟太阳光照射下,以布洛芬为目标污染物,考察了BiVO_4联合H_2O_2或K_2S_2O_8工艺对布洛芬的光催化降解效果,得出了H_2O_2或K_2S_2O_8的最佳投加量。通过淬灭实验,研究了光催化联合体系降解布洛芬的机制。X射线衍射谱图表明所合成的BiVO_4光催化剂为纯的单斜晶相,扫描电镜结果表明制备的粉末形貌单一,且呈现微球状。加入H_2O_2或K_2S_2O_8后,一定程度上促进了BiVO_4光催化降解布洛芬的效率,H_2O_2和K_2S_2O_8的最佳投加量分别为3.0 mmol·L^(-1)和1.5 g·L^(-1)。BiVO_4/H_2O_2/hν体系和BiVO_4/K_2S_2O_8/hν体系降解水中布洛芬主要是基于·OH自由基的氧化作用。通过对比2个体系中·OH和O^(·-)_2对布洛芬降解速率的贡献,发现K_2S_2O_8对BiVO_4光催化体系的促进作用远远大于H_2O_2对该体系的促进作用。

A BiVO4 photocatalyst was prepared by a hydrothermal process and was characterized using Xray diffraction（ XRD） and scanning electron microscopy（ SEM）. The photocatalytic degradation of ibuprofen（ IBU） by BiVO4 in the presence of H2O2 or K2S2O8under simulated solar irradiation was examined,and the optimum dosages of H2O2 and K2S2O8were determined. The photocatalytic degradation mechanism of IBU was studied through quenching experiments. XRD analysis indicated that the prepared photocatalyst corresponded to phase-pure monoclinic scheelite BiVO4. The SEM micrographs indicated that the prepared BiVO4 samples consisted of microspheres. The experimental results showed that both H2O2 and K2S2O8promote the photocatalytic degradation of IBU to some extent,and the optimum dosages of H2O2 and K2S2O8were 3. 0 mmol·L-1and 1. 5 g·L-1,respectively. The degradation mechanism of IBU in the two processes is mainly ascribed to ·OH oxidation. A comparison of the contribution of ·OH and O·-2in the two systems to the degradation rate of IBU showed that the BiVO4 photocatalytic activity in the presence of K2S2O8 was considerably better than that in the presence of H2O2.