FeVO_4可见光光催化降解有毒有机污染物

Photodegradation of toxic organic pollutants by FeVO_4 under visible light irradiation

采用液相沉淀法制备了FeVO4光催化剂,以X射线衍射法(XRD)、X射线光电子能谱(XPS)、紫外可见漫反射(UV-Vis DRS)对其进行了表征.在可见光(λ≥420 nm)照射下,研究了FeVO4活化H2O2降解染料OrangeⅡ及无色小分子2,4-二氯苯酚(DCP)的光催化活性.同时优化了光催化剂FeVO4的制备条件、探讨了光催化降解OrangeⅡ体系中H2O2浓度、FeVO4用量及pH对其降解作用的影响.结果表明,在可见光照射下,H2O2浓度为1.50×10-3 mol.L-1,FeVO4量为0.17 g.L-1,pH值为6.4时,FeVO4对OrangeⅡ光催化降解活性最好,14 h后对OrangeⅡ的矿化率达到51.6%.在光催化反应条件下,12 h后对DCP的降解率达到64.3%,表明FeVO4具有可见光催化特性.运用ESR技术跟踪测定光催化降解过程中氧化物种的变化,发现FeVO4活化H2O2产生羟基自由基(.OH),表明FeVO4的光催化降解过程主要涉及.OH的氧化历程.

Photocatalyst FeVO4 was prepared by liquid phase precipitation method, and characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and UV-Vis diffuse reflectance spectra （UV-Vis DRS）. The photodegradation of Orange Ⅱand 2, 4-dich]orophenol （DCP） by FeVO4 activating H2O2 under visible light illumination （λ≥ 420 nm） was used as probe reaction to explore the photocatalytie property of FeVO4. The effect of HEO2 concentration, FeVOg amount and pH on the photocatalytic activity was researched. The results demonstrated that FeVO4 had the best degradation efficiency under the conditions of H2O2 concentration 1.50 × 10-3 mol. L-1, FeVO4 amount 0. 17 g conditions, the mineralized rate of Orange II after 14 h and the degrada and pH 6.4. Under the optimal tion of DCP after 12 h were 51.6% and 64.3%, respectively. ESR results showed that the highly reactive oxygene species hydroxyl radical was produced during the reaction, which demonstrated that the degradation pro cess was dominated by generated in the system.