Department of Chemistry, Aligarh Muslim University, Aligarh-202002, UP, India.
Sci Total Environ. 2013 Aug 1;458-460:388-98. doi: 10.1016/j.scitotenv.2013.04.041. Epub 2013 May 14.
This paper deals with the study of photocatalyzed degradation of an insecticide, Thiamethoxam in aqueous suspension of TiO2. The adsorption of Thiamethoxam on TiO2 surface under dark conditions was also investigated in order to find out equilibrium adsorption constant. The degradation kinetics was studied using spectrophotometric method under various conditions such as substrate concentration, type of catalyst, catalyst dosage, pH, and in the presence of electron acceptors such as hydrogen peroxide, potassium bromate, and ammonium persulphate under continuous purging of atmospheric oxygen, and the degradation rates were found to be strongly influenced by these parameters. The results manifested that the photocatalysis of Thiamethoxam follows pseudo-first-order kinetics. The toxicity assessments of the irradiated samples were carried out using human erythrocytes as a model system under in vitro conditions. GC-MS study showed the formation of several intermediate products which were characterised based on their molecular mass and mass fragmentation pattern. A probable mechanism for the formation of various products formed during the photocatalytic process of Thiamethoxam was also proposed.
本文研究了在 TiO2 水悬浮液中光催化降解杀虫剂噻虫嗪的情况。还研究了噻虫嗪在黑暗条件下在 TiO2 表面的吸附情况，以确定平衡吸附常数。使用分光光度法在不同条件下研究了降解动力学，如底物浓度、催化剂类型、催化剂用量、pH 值，以及在大气氧连续吹扫下存在过氧化氢、溴酸钾和过硫酸铵等电子受体的情况下，并发现这些参数对降解速率有很大的影响。结果表明，噻虫嗪的光催化遵循准一级动力学。使用人红细胞作为模型系统在体外条件下对辐照样品进行了毒性评估。GC-MS 研究表明形成了几种中间产物，根据它们的分子量和质谱碎片模式对其进行了表征。还提出了噻虫嗪在光催化过程中形成各种产物的可能机制。
