Aarthi T, Narahari Prashanthi, Madras Giridhar
Department of Chemical Engineering, Indian Institute of Science, Bangalore 560012, India.
J Hazard Mater. 2007 Nov 19;149(3):725-34. doi: 10.1016/j.jhazmat.2007.04.038. Epub 2007 Apr 20.
The present study investigates the dependence of photocatalytic rate on molecular structure of the substrate that is degraded. The photocatalytic degradation of Azure (A and B) and Sudan (III and IV) dyes, having similar structure, but different functional groups, were investigated with two catalysts. The photocatalytic activity of solution combustion synthesized TiO(2) (CS TiO(2)) was compared with that of Degussa P-25 for degrading these dyes. The effect of solvents and mixed-solvent system on photodegradation of Sudan III was investigated. The photodegradation rate was found to be higher in solvents with higher polarity. The effect of pH and the presence of metal ions in the form of chloride and nitrate salt, on degradation rate of Azure A was also investigated. The metal ions significantly reduced the photocatalysis rates. A detailed Langmuir-Hinshelwood kinetic model has been developed to explain the effect of metal ions on degradation rate of the substrate. This model elucidates the contribution of holes and electrons towards degradation of the dye.
本研究考察了光催化速率对被降解底物分子结构的依赖性。使用两种催化剂研究了结构相似但官能团不同的天青（A和B）以及苏丹（III和IV）染料的光催化降解。将溶液燃烧合成的TiO₂（CS TiO₂）与德固赛P-25降解这些染料的光催化活性进行了比较。研究了溶剂和混合溶剂体系对苏丹III光降解的影响。发现光降解速率在极性较高的溶剂中更高。还研究了pH值以及氯化物和硝酸盐形式的金属离子的存在对天青A降解速率的影响。金属离子显著降低了光催化速率。已建立了详细的朗缪尔-欣谢尔伍德动力学模型来解释金属离子对底物降解速率的影响。该模型阐明了空穴和电子对染料降解的贡献。
