The reductive degradation of 1,1,1-trichloroethane by Fe(0) in a soil slurry system
Most studies on the treatment of chlorinated contaminants by Fe(0) focus on aqueous system tests.However,few is known about the effectiveness of these tests for degrading chlorinated contaminants such as 1,1,1-trichloroethane (TCA) in soil.In this work,the reductive degradation performance of 1,1,1- TCA by Fe(0) was thoroughly investigated in a soil slurry system.The effects of various factors including acid-washed iron,the initial 1,1,1-TCA concentration,Fe(0) dosage,slurry pH,and common constituents in groundwater and soil such as Cl-,HCO3-,SO42-,NO3-anions and humic acid (HA) were evaluated.The experimental results showed that 1,1,1-TCA could be effectively degraded in 12 h for an initial Fe(O) dosage of 10 g L-1 and a soil/water mass ratio of 1/5.The soil slurry experiments showed two-stage degradation kinetics: a slow reaction in the first stage and a fast reductive degradation of 1,1,1-TCA in the second stage.The reductive degradation of 1,1,1-TCA was expedited as the mass concentration of Fe(O) increased.In addition,high pHs adversely affected the degradation of 1,1,1-TCA over a pH range of 5.4-8.0,and the reductive degradation efficiency decreased with increasing slurry pH.The initial 1,1,1-TCA concentration and the presence of Cl-and SO42-anions had negligible effects.HCO3-anions had a acceerative effect on 1,1,1-TCA removal,and both NO3-and HA had inhibitory effects.A Cl-mass balance showed that the amount of Cl-ions released into the soil slurry system during the 1,1,1-TCA degradation increased with increasing reaction time,suggesting that the main degradation mechanism of 1,1,1-TCA by Fe(O) in a soil slurry system was reductive dechlorination with 1,1-DCA as the main intermediate.In conclusion,this study provides a theoretical basis for the practical application of the remediation of contaminated sites containing chlorinated solvent.
1,1,1-TCA Reductive degradation Fe(O) Soil slurry
Xiaoliang Wu Shuguang Lu
State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process,East China University of Science and Technology,Shanghai 200237,China
国内会议
第十一届全国博士生学术年会专题——节能环保与污染防治技术分会场论坛
成都
英文
414-428
2013-10-01（万方平台首次上网日期，不代表论文的发表时间）