漂白废水中氯酚光催化降解及其动力学研究

Study of Nanometer TiO_2 Photocatalytic Degradation of Chlorophenol and Its Kinetics

氯酚是纸浆漂白废水中常含有的有毒、难降解污染物,本文研究了4-氯酚和2,4-二氯酚在负载纳米TiO_2膜的反应器中的降解。结果显示,在TiO_2和UV同时存在的情况下才能有效地光催化降解废水中的氯酚,光照强度越大,pH值越高,氯酚的去除率也越高;TiO_2光催化氧化氯酚水溶液的动力学可以用L-H动力学方程描述,加入少量H_2O_2,仍遵守一级动力学反应,而且能增大表观一级反应速率常数。

Chlorophenol is the main toxic organic compound of effluent from pulp mill. The photocatalytic degradation of chlorophenol in wastewater was studied in a self-designed reaction apparatus containing nanometer TiO_2, catalyst. The results showed that the degradation ef- fectively occurs under the co-existence of UV and TiO_2. The photodegradation rate of chlorophenol increases as the light intensity and pH value increase. When the reaction time is 2 hour, the removal rate of 4-CP and 2,4-DCP respectively achieves 73.0% and 54.9%. Photo- catalytic degradation of 4-CP and 2,4-DCP in aqueous solution can be described in langmuir-Hinshelwood kinetics model. With the addi- tion of H_2O_2, it still follows the first order reaction of kinetics and makes their first order rate constants larger.