Fe_3O_4/TiO_2-H_2O_2非均相类Fenton体系对3,4-二氯三氟甲苯的降解

Degradation of 3,4-dichlorobenzotrifluoride by Fe_3O_4/TiO_2-H_2O_2 heterogeneous Fenton-like system

用Fe_3O_4/Ti O_2-H_2O_2体系对3,4-二氯三氟甲苯(3,4-DCBTE)进行降解反应研究,同时考察了pH值、催化剂投加量、H_2O_2投加量、温度等因素对3,4-DCBTE降解效率的影响.实验结果表明,Fe_3O_4/Ti O_2-H_2O_2非均相类Fenton体系对3,4-二氯三氟甲苯的处理效果极佳;并且在H_2O_2投加量为45.0 mg·L^(-1)、Fe_3O_4/TiO_2的物质的量比为1∶1、pH=3.0、温度为40.0℃的条件下反应效果最佳,去除率高达99.1%.同时从实验结果可以看出,pH在2.0~7.0范围内该体系对3,4-二氯三氟甲苯均有降解效果,说明该体系相比于传统的Fenton体系有较宽的pH适用范围.目标污染物的降解符合一级反应动力学,其发生反应所需的活化能为36.9 k J·mol^(-1).

The degradation of 3,4-dichlorobenzotfifluoride （3,4-DCBTE） was conducted in the heterogeneous Fenton-like system, using nanoscale Fe3O4/TiO2 as a catalyst. The effects of pH, the dosage of the catalyst and H2O2 , temperature and the molar ratio of Fe3O4/TiO2 on the degradation efficiency of 3,4-DCBTE were also investigated. Results show that the heterogeneous Fenton-like system was an effective method to remove 3,4-DCBTE, with the removal ratio of 99.1% under the optimized condition, with the concentration of H2O2 45.0 mg·L-1 , Fe3O4/TiO2 in 1： 1, pH 3.0 and 40 ℃. Compared with the traditional Fenton reaction, Fe3 O4/TiO2-H2O2 performed well under wider range of pH. The results also suggest that the reaction followed the first-order kinetics and the thermodynamic analysis demonstrated that the reaction activation energy was only 36.9 kJ· mol-1.