光助Fenton氧化法去除水中两种氯乙酸及其动力学研究

Photo-Aided Fenton Oxidation for the Removal of Dichloroacetic Acid and Trichloroacetic Acid in Water and the Kinetics

以二氯乙酸和三氯乙酸为目标污染物,研究了光助Fenton氧化去除水中卤乙酸的可行性及影响因素,并对其动力学进行了初步研究。结果表明,影响光助Fenton氧化的因素很多,氙灯功率500 W、H2O2和Fe2+投加量分别为5.0和1.0mmol.L-1、pH=4.0反应60min是所考察范围内的最佳降解条件,浓度为100μg.L-1的二氯乙酸和三氯乙酸的降解率分别为90.32%、87.77%;在实际水质pH=7.0时,相同浓度的二氯乙酸和三氯乙酸的降解率分别为75.34%、68.80%。紫外辐射与Fenton氧化对二氯乙酸和三氯乙酸的降解具有协同效应。光助Fenton氧化对二氯乙酸和三氯乙酸的降解符合一级反应动力学,表观活化能分别为30.11、31.09kJ.mol-1,受温度影响不大。

The feasibility and affecting factors for removal of haloacetic acids in water were studied by.using dichloroacetic acid （DCAA） and trichloroacetic acid （TCAA） as model compounds. The kinetics was further investigated. It is shown from the results that there are many factors which influence the photo-aided Fenton oxidation of DCAA and TCAA. The best condition was： the power of UV lamp was 500 W, Fe^2＋ and H2O2 concentrations were 1.0 and 5.0 mmol · L^-1 , respectively, and the initial pH was 4. 0, re- action time was 60 min. Under that condition, the degradation efficiencies of DCAA and TCAA with an initial concentration of 100 μg · L^-1 were 90. 32% and 87.77%, respectively. When the initial pH was 7.0, the degradation efficiencies of DCAA and TCAA with the same concentration were 75. 34% and 68.80%, respectively. A significant synergistic effect of UV irradiation and Fenton reagent was ob- served. The kinetics for degradation of DCAA and TCAA by photo-aided Fenton oxidation conforms to a pgeudo first-order reaction. The apparent activation energy for degradation of DCAA and TCAA w.ere 30. 11 and 31.09 kJ · mol^-1 , respectively, indicating the influence of temperature to the .reaction is not pronounced.