光催化氧化苯甲酸的动力学分析  

Photocatalytic degradation kinetics of benzoic acid

作　　者：于秀娟[1] 王永强[1] 孙德智[1] 

机构地区：[1]哈尔滨工业大学市政环境工程学院

出　　处：《哈尔滨工业大学学报》2008年第6期860-864,共5页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金资助项目(50378027)

摘　　要：为探讨Degussa P-25 TiO2光催化氧化降解苯甲酸的反应条件,采用悬浮态反应体系,以紫外灯(λmax=254 nm)为光源,考察苯甲酸光催化过程中反应体系初始pH、催化剂质量浓度、初始苯甲酸质量浓度、H2O2投加量对光催化氧化速率的影响.实验结果表明:在pH=3.5时光催化氧化效果最佳,当催化剂质量浓度为0.05 g/L时,TOC去除率为87.2%;催化剂质量浓度大于0.1 g/L时,在反应初始阶段吸附作用为主要控制步骤,但是随着反应的进行,传质和光源的利用率成为主要控制步骤;随着苯甲酸质量浓度的增加,反应由一级向零级过渡;外加H2O2能够提高反应速率,其最佳投加量为1.5 mg/L.在低底物质量浓度时,苯甲酸的光催化氧化过程符合准一级动力学模型.In order to investigate the degradation conditions of photocatalytic oxide benzoic acid with titanium dioxide （ Degussa P25 ）, the photocatalytic degradation of benzoic acid （BA） was investigated using UV radiation （ λmax = 254 rim） in the suspension system as a function of pH, TiO2 amount, initial concentration of BA （[ BA]0） and H2O2. It was found that the reaction would be going on with the optimum pH = 3.5 and 0.05 g/L concentration of TiO2. The reaction rate increased with catalyst amounts and reached a maximum at 0. 1 g/L because of high catalyst amounts to obstruct light transmission. With the increase of the initial concentration of BA, changes of the apparent rate constants could be found from the first-order reaction model to the zero one. The optimal concentration of hydrogen peroxide was 1.5 mg/L. The photocatalytic degradation rate followed pseudo-first order kinetics when the concentration of benzoic acid was low concentration.

关 键 词：光催化氧化 TIO2 动力学方程 苯甲酸 

分 类 号：X703.1[环境科学与工程—环境工程]