利用酒石酸土柱淋洗法修复重金属污染土壤

Leaching remediation of a heavy metal contaminated soil using tartaric acid

通过室内模拟试验,采用土柱淋洗方法,研究酒石酸溶液两种不同添加方式对冶炼厂土壤中重金属离子去除率的影响,采用连续分级方法研究了淋洗前后冶炼厂土壤中重金属形态的变化.结果表明,2.5L酒石酸5次加样的淋洗效果明显好于10次加样的淋洗效果,其中5次加样淋洗能去除91.3%的Cd,11.1%的Pb,39.2%的Zn,11.1%的Cu;淋洗过程中铅的穿透曲线明显滞后于镉、铜和锌3种重金属离子.形态分级结果表明,酒石酸5次加样淋洗能有效去除污染土壤中交换态和碳酸盐结合态部分重金属离子,明显降低氧化物结合态部分重金属离子,而对有机态和残余态部分重金属离子作用效果不明显.可见用酒石酸土柱淋洗法修复重金属污染的土壤是可行的.

The remediation of a heavy metal （HM） contaminated soil was studied by using an environmentallyfriendly extraetant of tartaric acid. Column leaching experiments were performed to analyze the effects of tartaric acid five-portion style leaching and ten-portion style leaching on heavy metals removal as well as the differences of heavy metals speciation before and after tartaric acid treatment. Results show that 2. 5 L tartaric acid five-portion style leaching was more effective than ten-portion style leaching for removal of heavy metals from the contaminated soil, attaining 91.3% Cd, 11.1% Pb, 39.2% Zn and 11.1% Cu. The breakthrough curve of lead was slower than otherthree heavy metals. Sequential fractionations of treated and untreated soil samples showed that tartaric acid was very effective in removing the exchangeable and carbonate fractions of heavy metals from the contaminated soils. The con tents of heavy metals in Fe-Mn oxide fraction were also significantly decreased by tartaric acid leaching treatment. The heavy metals in organic matter fraction and residual fraction could not be removed by tartaric acid. This indicates that tartaric acid is a promising agent for remediation of HM contaminated soils. However, further research is required before the method can be used for in situ remediation of contaminatedsites.