Kinetics and mechanism of photocatalytic degradation of metobromuron by TiO2 in simulated sunlight
Kinetics and mechanism of photocatalytic degradation of metobromuron by TiO2 in simulated sunlight
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DOI：
10.1007/s11164-012-0957-3
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发表时间：
2012
影响因子：
3.3
通讯作者：
Hai Yang;Jiyong Deng;Huajie Liu;Weiwei Yan;Liping Yang;B. Yi
中科院分区：
文献类型：
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作者：
Hai Yang;Jiyong Deng;Huajie Liu;Weiwei Yan;Liping Yang;B. Yi
系统地研究了在模拟太阳光照射下，以TiO2光催化剂为光催化剂的水溶液中百菌清的光催化降解动力学。采用单变量一次法和基于响应面方法的中心复合设计，研究了几种经典条件对光催化效率的单独和协同效应。研究发现，三种不同的条件，即二氧化钛浓度、pH值和甲基溴隆的初始浓度，独立地决定了降解效率。最佳降解条件为：二氧化钛浓度为3.00 mg/L，pH值为7.88，甲草隆初始浓度为60.23μM。根据实验结果和前线电子密度和点电荷的理论计算，初步提出了甲草隆的降解机理。结果表明，在光催化降解的初始阶段，溴原子的取代、·OH自由基的加入和尿素侧链的断裂是主要的降解途径。
The kinetics of photocatalytic degradation of metobromuron in aqueous solution, with TiO2 as photocatalyst under simulated sunlight irradiation, have been systematically investigated. The single-variable-at-a-time method and the central composite design based on response surface methodology were used to study the individual and synergistic effects of several classical conditions on the efficiency of photocatalysis. Three different conditions, TiO2 concentration, pH, and initial concentration of metobromuron, were found to independently determine the efficiency of degradation. The optimum degradation conditions were: TiO2 concentration 3.00 g/L, pH 7.88, and initial concentration of metobromuron 60.23 μM. In addition, a mechanism of degradation of metobromuron is tentatively proposed on the basis of the experimental results and theoretical calculation of frontier electron densities and point charges. The results suggest that substitution of the Br atom, addition of ·OH radicals, and the cleavage of urea side chain are the predominant degradation pathways during the initial stage of photocatalytic degradation.