Hasnat M A, Uddin M M, Samed A J F, Alam S S, Hossain S
Department of Chemistry, Shahjalal University of Science and Technology, Sylhet-3114, Bangladesh.
J Hazard Mater. 2007 Aug 17;147(1-2):471-7. doi: 10.1016/j.jhazmat.2007.01.040. Epub 2007 Jan 16.
The UV radiation assisted photocatalytic decolorization/degradation kinetics of an anionic dye erythrosine (ER), has been studied over TiO2 and ZnO surfaces. Since adsorption is the prerequisite condition for decolorization/degradation of dye molecules in presence of heterogeneous catalysis, the Langmuir and Freundlich isotherms were examined to verify the adsorption intensity. Standard adsorption free energy measurement implies that the adsorption of ER on both TiO2 and ZnO surfaces is spontaneous endothermic process. The effect of catalyst loading (TiO2/ZnO) revealed the fact that the maximum decolorization rate is obtained under an optimized catalyst loading condition. The decolorization efficiency was also investigated over the pH range of 5.0-10.0 indicating that increasing pH enhances decolorization efficiency. The influence of H2O2 on decolorization efficiency was found noticeable since it is a hydroxyl radical provider. The kinetic study of this degradation indicates that under the experimental condition, the decolorization mechanism follows zero order kinetics on the basis of Langmuir-Hinshelwood (L-H) heterogeneous reaction mechanism.
在TiO₂和ZnO表面上，研究了紫外线辐射辅助光催化对阴离子染料赤藓红（ER）的脱色/降解动力学。由于在非均相催化存在下，吸附是染料分子脱色/降解的先决条件，因此研究了朗缪尔等温线和弗伦德利希等温线，以验证吸附强度。标准吸附自由能测量表明，ER在TiO₂和ZnO表面上的吸附是自发吸热过程。催化剂负载量（TiO₂/ZnO）的影响表明，在优化的催化剂负载条件下可获得最大脱色率。还研究了在pH值为5.0 - 10.0范围内的脱色效率，结果表明pH值升高会提高脱色效率。由于H₂O₂是羟基自由基的提供者，发现其对脱色效率有显著影响。该降解过程的动力学研究表明，在实验条件下，基于朗缪尔 - 欣谢尔伍德（L - H）非均相反应机理，脱色机理遵循零级动力学。
