臭氧氧化降解水中三氯乙烯的效能研究  

Efficient degradation of trichloroethylene (TCE) in water by ozone oxidation

作　　者：陈行行 白智勇 李群 杨琦 

机构地区：[1]中国地质大学(北京)水资源与环境学院,水资源与环境工程北京市重点实验室,北京100083

出　　处：《环境科学学报》2017年第12期4586-4592,共7页Acta Scientiae Circumstantiae

基　　金：北京市产学研项目(No.51900265005);国家水体污染控制与治理科技重大专项(No.2009ZX07207-008,2009ZX07419-002,2009ZX07207-001,2015ZX07406005-001);中央高校基本科研业务费专项资金(No.2652013101,2652013086,2652013087);国家重大科学仪器设备开发专项(No.2012YQ060115)~~

摘　　要：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.As a typical representative halogenated hydrocarbon in groundwater,trichloroethylene（TCE）has shown high detection rate,volatility and carcinogenicity.Therefore,the treatments of TCE in groundwater have gained more attention recently.In this work,the degradation efficiency of TCE by ozone oxidation was studied.The effects of ozone dosage,initial p H,temperature and initial TCE concentration on the degradation of TCE were investigated.Moreover,the reaction products and the possible ozone oxidation mechanism were proposed.The experimental results show TCE could be completely degraded after 2 h under the optimized experimental conditions（p H=9,ozone dosage 5 mg·L^-1,TCE initial concentration 1 mg·L^-1,temperature 30℃）,and the dechlorination rate of TCE could reach 71.1%at the end of the reaction.The kinetics study results show that the reaction of ozone oxidation was consistent with pseudo-first-order kinetics,while the thermodynamic studies showed that the change of reaction enthalpy（ΔH）,the entropy（ΔS）and the activation energy（E_a）were 15.53 k J·mol^-1,-226.5 J·mol^-1·K^-1,and 18.05 k J·mol^-1,respectively,indicating that the reaction between ozone and TCE is easy to occur.In addition,TCE degradation by ozone is mainly attributed to the hydroxyl radicals formed in ozone decomposition.

关 键 词：臭氧氧化 三氯乙烯 羟基自由基 伪一级动力学 

分 类 号：X703[环境科学与工程—环境工程]