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卤代烃是地下水污染中常见的有机污染物,三氯乙烯(Trichloroethylene,TCE)作为一种典型的卤代烃,具有高检出率、易挥发、致癌性等特征,而对地下水中TCE的治理一直是研究的热点.因此,本文以TCE为目标污染物,采用臭氧氧化技术对其进行降解效能分析,重点考察了不同臭氧投加量、初始p H、温度、初始TCE浓度对臭氧氧化降解水中TCE的影响,并对反应产物及可能的臭氧氧化机理进行了推测.结果表明,溶液的初始p H、臭氧投加量、初始TCE浓度均会对TCE的降解效率和降解速率产生一定的影响.在优化的实验条件下(p H=9、臭氧投加量5mg·L~(-1)、TCE初始浓度1 mg·L~(-1)、温度30℃),TCE在2 h的降解率可以达到100%,反应结束后TCE脱氯率为71.1%.动力学实验表明,臭氧氧化TCE的反应符合伪一级动力学.热力学研究表明,臭氧氧化TCE的焓变(ΔH)为15.53 k J·mol~(-1),熵变(ΔS)为-226.5 J·mol~(-1)·K~(-1),活化能E_a为18.05 k J·mol~(-1),表明臭氧氧化TCE的反应易于进行.机理研究表明,臭氧氧化降解TCE主要是由臭氧分解所形成的羟基自由基进行的.
Halocarbons are common organic pollutants in groundwater pollution. Trichlorethylene (TCE), as a typical halogenated hydrocarbon, has high detection rate, volatility and carcinogenicity. However, TCE in groundwater Therefore, it is always a research hotspot.Therefore, in this paper, TCE is the target pollutant, and its degradation efficiency is analyzed by ozone oxidation technology, focusing on the effects of different ozone dosage, initial pH, temperature, initial TCE concentration on ozone oxidative degradation TCE in water and the reaction mechanism and possible mechanism of ozone oxidation were presumed.The results showed that the initial p H, ozone dosage and initial TCE concentration all had a certain impact on the degradation efficiency and degradation rate of TCE Under the optimized experimental conditions (p H = 9, ozone dosage 5 mg · L -1, TCE initial concentration 1 mg · L -1, temperature 30 ℃), the degradation of TCE in 2 h The rate of TCE dechlorination can reach 100%, and the rate of TCE dechlorination after the reaction is 71.1% .Kinetic experiments show that the reaction of ozonized TCE accords with pseudo first order kinetics. The thermodynamic studies show that the enthalpy change (ΔH) of ozonized TCE is 15.53 k J · mol ~ (-1) and entropy change (ΔS) of -226.5 J · mol -1 K -1, E_a of energy is 18.05 k J · mol ~ (-1), it indicates that ozonation reaction TCE easy. Mechanistic studies suggest that ozonation TCE mainly hydroxyl radicals formed by the ozonolysis performed.