化学氧化强化化学淋洗修复汞污染土壤的试验研究

Experimental Study on Remediation of Mercury Contaminated Soil by Chemical Oxidation Enhanced Chemical Leaching

分别采用KI、Na2S2O3、EDTA溶液对汞污染土壤进行淋洗修复,筛选出修复效果最好的淋洗剂,确定了最佳淋洗工艺条件,并研究了化学氧化对化学淋洗修复汞污染土壤的强化作用。结果表明,Na2S2O3溶液对汞的淋洗效果最好,最佳淋洗工艺条件为Na2S2O3浓度0.05 mol/L、固液比1∶6(g/mL)、淋洗时间5 h,在此条件下,土壤中汞的淋洗效率达到62.54%。化学氧化能大大提高土壤汞的淋洗效率,经化学氧化强化化学淋洗处理后,土样汞含量降低到1.65 mg/kg,且淋洗效率达到78.85%。

The mercury contaminated soil was remediated by washing with KI,Na2S2O3,EDTA solution,respectively.The best leaching agent was screened,the best leaching conditions were determined and the strengthening effect of chemical oxidation on the remediation of mercury contaminated soil by chemical leaching was studied.The results showed that the Na2S2O3 solution had the best leaching effect on mercury.The best leaching conditions for Na2S2O3 solution were:Na2S2O3 concentration 0.05 mol/L,solid-to-liquid ratio(g/mL)1∶6,leaching time 5 h.Under these conditions,the leaching efficiency of mercury in soil was 62.54%.Chemical oxidation could greatly improve the leaching efficiency of mercury in soil.After the treatment of chemical oxidation enhanced chemical leaching,the mercury content of soil sample decreased to 1.65 mg/kg,and the leaching efficiency was 78.85%.