过硫酸钠对砂壤土中三氯乙烯的氧化研究

摘要

To investigate the removal efficiency of trichloroethylene (TCE) in sandy loam, the oxidant of sodium persulfate (Na2S2O8 ) and activating agent of citrate acid (CA) chelated with ferrous iron (Fe Ⅱ) were wsed. The orthogonal test showed that the removal efficiency of TCE was over 93% with different TCE treatments under the optimized experimental condition consisting of 5 mmol/L of Na2S2O8 , 2.5 mmol/L of Fe( Ⅱ) and 0.25 mmol/L CA with 30 min of reaction time. For soil with higher TCE level, sequential.oxidation treatment could remove more contaminant. In addition, results from soil column experiments showed that: more than 88.9% of TCE was oxidized by Na2S2O8 after 7 d; and the removal rate of TCE was relevant to the way ofNa2S2O8 addition which sequential addition could achieved the best efficiency.%以过硫酸钠(Na2S2O8)为氧化剂,柠檬酸(CA)螯合Fe( II)溶液作为活化剂,对砂壤土中的三氯乙烯(TCE)进行处理.采用正交试验获得优化操作条件为:Na2S2O8浓度5mmol/L,Fe(II)浓度2.5mmo1/L,CA浓度0.25mmol/L,反应时间30min.在此条件下,土壤中不同浓度的TCE去除率均在93％以上.对于污染程度高的土壤,采用连续氧化处理可达到较高的修复目标要求.土柱实验结果表明经过Na2S2O8溶液氧化7d后,TCE氧化率达到88.9％以上,且去除效果与处理方式有关,分次加入方式的效果最好.