TiO2悬浮体系光催化降解反应动力学模型的建立

摘要

以纳米材料TiO2作为光催化剂，乙酰甲胺磷(DMAPT)作为目标化合物，在DGF-1型多功能光化学反应仪上研究了悬浮体系TiO2光催化降解反应的动力学模型.模型中的主要参数有:TiO2用量、入射光强、反应器的几何半径、反应器的经验参数、反应物初始浓度、羟基自由基二级速率常数及已知化合物的物理性质(分子的摩尔体积和溶解度).模型较好地预测了其他化合物(如三氯乙烯(TCE)、四氯乙烯(PCE)、对-二氯苯(DCB)和四氯化碳(CTC))的光催化降解.对C0(TCE)=22.1mg/L，C0(PCE)=20mg/L和C0(DEB)=40mg/L的反应物，完全降解所需的时间分别为3，4和5min.入射光强在1.38～6.05W/cm2范围时，反应速率与光强的0.5次方成正比，催化剂最佳用量随着入射光的增强而增加.%With O,S-dimethyl acetyl ph osphoramidothioate(DMAPT) asobjective compound, the kinetics model for TiO2- photocat alyzed degradation in suspending system was studied in DGF-1 model photoc hemistry re action instrument. The main parameters involved in the model are TiO2 dosage , effective light intensity, geometrical radius and empirical parameter of the reactor, initial concentration of the reactant, rate constants of the se cond-order reaction of OH.radical， and p hysical properties of the reactant(such as molar volume and aqueous so lubility). The different DMAPT concentrations were used to validate the funtion. The model preferably predicted the photocatalytic degradation of other compounds, such as trichloroethylene(TCE), tetrachloroethylene(PCE), p -di chlorobeneze(DCB) and carbon tetrachloride(CTC). For the system withC0 (TCE)=22.1 mg/L, C0(PCE)=20 mg/L, C0(DCB)=40 mg/L, the time needed for complete degr adation is 3, 4 and 5 min respectively. The reaction rate is proportional to the half-order of incident light intensity within the range of 1.38～6.05 W/cm2. The optimum catalyst dosage increases with increasing the incident light intensity.