Impact of pH on the kinetics of photocatalytic oxidation of 2,4-dichlorophenoxy acetic acid in a fluidized bed photocatalytic reactor
Impact of pH on the kinetics of photocatalytic oxidation of 2,4-dichlorophenoxy acetic acid in a fluidized bed photocatalytic reactor
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DOI：
10.1016/j.apcatb.2016.12.038
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发表时间：
2017-05
影响因子：
22.1
通讯作者：
R. Rezaei;M. Mohseni
中科院分区：
文献类型：
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作者：
R. Rezaei;M. Mohseni
研究了 pH 对 2,4-二氯苯氧基乙酸 (2,4-D) 光催化氧化动力学的影响。使用TiO2光催化剂球在流化床光催化反应器中进行实验。氧化速率受溶液pH值的影响。在酸性介质中，根据动力学模型，氧化速率较高，因为速率常数与紫外线强度（I）直接相关；而在 pH 7 时，这种关系简化为函数平方根（即 I1/2）。此外，pH 会导致光催化氧化机制的改变。在pH 7时，光催化氧化发生在远离光催化剂表面的地方，氧化速率遵循一级动力学。另一方面，在酸性条件下，氧化主要发生在光催化剂的表面，氧化速率遵循Langmuir-Hinshelwood 和一级动力学模型的组合。
The impact of pH on the kinetics of photocatalytic oxidation of 2,4-dichlorophenoxy acetic acid (2,4-D) was investigated. Experiments were performed in fluidized bed photocatalytic reactor using TiO2photocatalyst spheres. The rate of oxidation was affected by the solution pH. In acidic medium, according to the kinetic model, the rate of oxidation was higher because the rate constant was directly related to UV intensity (I); whereas this relationship reduced to a functional square root (i.e.,I1/2) at pH 7. In addition, pH resulted in changing the photocatalytic oxidation mechanism. At pH 7, the photocatalytic oxidation took place away from the photocatalyst surface, the oxidation rate followed first order kinetics. Under acidic condition, on the other hand, the oxidation mostly took place on the surface of photocatalyst and the rate of oxidation followed a combination of the Langmuir-Hinshelwood and first order kinetic models.