以五氯酚钠和氯代愈创木酚为目标物,在TiO2悬浮体系中对它们的暗吸附和紫外光催化氧化行为进行了研究,考察吸附和动力学的关系。实验表明,固体催化剂与溶液中组分的吸附在20min内可以达到平衡,消除了光催化过程中吸附外扩散对反应速率的影响,得出了吸附平衡常数。研究了悬浮体系光催化反应的影响因素。获得了相关参数与反应速率间的定量关系。在实验基础上提出了有机氯化物光催化降解的动力学模型。
Abstract: The photocatalytie oxidation reaction and the reference reaction in UV-inadiated Ti02 suspension system with Na-PEP and 4-chloro-2- methoxyphenol as simulating compounds were investigated. Experimental results showed that the adsorption of solid catalyst reaches equilibrium in 20 min. The adsorption equilibrium constant is expressed as K =(Cs/C0)^-βRT/Vm/C0[1-(Cs/C0)^-βRT/Vm]The reaction kinetics was studied based on Na-PCP photocatalytic degradation. The effects of initial Na-PCP concentration, dosage of catalyst TiO2, pH of solution and UV-radiation intensity etc on the reaction kinetics were investigated. Langmuir rate constant expression is k = S(1 - 0.318C0)I0^0.9477 1/R^2Rλ^2D^2-n(RRλD+e^RRλD-1)[0.00853+0.085e^-(pH-5.89)^2].A kinetic model is proposed from pseudo fast order Langmuir-Hinshelwood equation such as t=1/kKln(C0/C1)+1/k(C0-C1) to describe heterogeneous photocatalytic system. Based on the proposed model, the calculated value is in accordance with that from the 4-chloro-2- methoxyphenol degradation experiments. The correlation test result is R = 0.9673, which indicates that the kinetic model is relatively rational.