载铁沸石分子筛催化降解地下水中氯代烃的影响因素及机制研究  

Catalytic Degradation of Chlorinated Hydrocarbons by Fe-zeolite:Influence Factors and Degradation Mechanism

作　　者：潘杰 李越煊 李鹏飞 王萍[1] 吕正勇[5] 叶茂[2,3] 李静文 董元华[2,3] 刘云[2,3,4] PAN Jie;LI Yue-xuan;LI Peng-fei;WANG Ping;LU Zheng-yong;YE Mao;LI Jing-wen;DONG Yuan-hua;LIU Yun(School of Chemistry and Biological Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;CAS Key Laboratory of Soil Environment and Pollution Remediation,Institute of Soil Science,Chinese Academy of Sciences,Nanjing 210008,China;University of Chinese Academy of Sciences,Beijing 100049,China;National Engineering Laboratory for Site Remediation Technologies,Beijing 100015,China;Beijing GeoEnviron Engineering&Technology,Inc.,Beijing 100095,China)

机构地区：[1]兰州交通大学化学与生物工程学院,甘肃兰州730070 [2]中国科学院土壤环境与污染修复重点实验室(南京土壤研究所),江苏南京210008 [3]中国科学院大学,北京100049 [4]污染场地安全修复技术国家工程实验室,北京100015 [5]北京高能时代环境技术股份有限公司,北京100095

出　　处：《生态与农村环境学报》2021年第1期103-109,共7页Journal of Ecology and Rural Environment

基　　金：国家重点研发计划(2018YFC1803100);污染场地安全修复技术国家工程实验室开放基金(NEL-SRT201902)。

摘　　要：氯代烃是工业场地地下水中常见污染物,高效去除氯代烃是目前环境科学研究的热点。以负载铁的沸石分子筛(Fe-ZSM-5)为催化剂,研究Fe-ZSM-5催化降解三氯乙烷(TCE)的影响因素及降解机制。结果表明,在Fe-ZSM-5体系中,加入0.8 g·L^-1 Fe-ZSM-5、10 mmol·L^-1 H2O2、0.9 mmol·L^-1 TCE、初始pH值为7.4、25℃条件下,TCE降解率可达88%,且随着催化剂用量和H2O2浓度的增大,同一浓度TCE的去除率逐渐升高,降解率最高可以达到99%。此外,改变溶液初始pH值,对TCE的降解无显著影响。与Fe-ZSM-5体系相同条件下,未负载铁的沸石分子筛(ZSM-5)体系催化H2O2降解TCE的去除率仅为41%,H2O2浓度从6增至14 mmol·L^-1,TCE去除率反而降低,溶液初始pH对去除率也无显著影响。自由基猝灭试验发现,在Fe-ZSM-5催化体系中,羟基自由基(·OH)对TCE的降解起主导作用,而未负载铁的ZSM-5催化体系中,·OH的作用则不明显。Chlorinated hydrocarbons are among the most common pollutants at industrial sites and have been detected widespreading in both soil and groundwater.Because of their environmental persistence and toxicities,there is a growing interest in developing new technologies for the removal of chlorinated hydrocarbons in the environment.The degradation of a typical chlorinated hydrocarbon,trichloroethane(TCE)by hydrogen peroxide(H2O2)was studied by using an iron-loaded zeolite(Fe-ZSM-5)as heterogeneous catalyst.In the Fe-ZSM-5/H2O2 system,the removal rate of TCE(0.9 mmol·L^-1)reached 88%with 0.8 g·L^-1 Fe-ZSM-5 and 10 mmol·L^-1 H2O2 at initial pH 7.4 and ambient temperature.And with the increasing of catalyst dosage and H2O2 concentration,the removal rate of TCE gradually increased,and the removal rate could reach up to 99%.In addition,initial pH had minor effect on the degradation of TCE.Compared with Fe-ZSM-5,the degradation rate of TCE was only 41%by ZSM-5 without iron loading,and the removal rate decreased when H2O2 concentration increased from 6 mmol·L^-1 to 14 mmol·L^-1,while the initial pH had also a minor effect on the removal rate of TCE.The results of free radical quenching experiment show that·OH played a major role in the degradation of TCE in Fe-ZSM-5/H 2O 2 system,which was largely absent in ZSM-5/H2O2 system.

关 键 词：改性分子筛 三氯乙烯(TCE) 自由基 过氧化氢(H2O2) 

分 类 号：X53[环境科学与工程—环境工程]