表面活性剂对土壤中重金属清洗及有效态的影响

采用两种常用的表面活性剂-十二烷基苯磺酸钠(阴离子型)、Tween-80(非离子型),对锦州铁合金厂周边Zn、Cd及Pb重金属污染土壤进行化学修复试验,研究两种表面活性剂对重金属Zn、Cd及Pb的去除率及化学形态影响.结果表明,随着表面活性剂浓度的提高,两种表面活性剂对Pb、Cd及Zn的去除作用增强,Tween-80溶液的浓度越高,对重金属的萃取效果越好,对重金属的去除能力大小顺序为Cd>Zn>Pb,最大去除率分别为83.07%、56.78%及42.57%;十二烷基苯磺酸钠在低浓度时对Cd和Pb的去除效果不明显,而对金属Zn的去除效果较好,在0.09 mol.L-1时达到最大值83.86%;与淋溶前土壤中重金属有效态含量相比较,经不同浓度十二烷基苯磺酸钠淋洗后土壤中Cd有效态含量随LAS浓度的升高而先增加后下降,而Pb的有效态含量随十二烷基苯磺酸钠升高而增加;经不同浓度Tween-80淋洗后土壤中Zn及Cd有效态含量都是随Tween-80浓度的升高而先增加后下降,Pb有效态含量随Tween-80升高而下降.

Extraction and availabilities of heavy metals in the soil by surfactants

The two surfactants,dodecyl benzene sulfonic acid sodiumsalt(LAS) and Tween-80 were applied to remediate the soils contaminated with Pb,Cd,and Zn in Jinzhou.The effects of the surfactant on eliminating Pb,Cd,and Zn and chemical form were studied.LAS and Tween-80 showed remarkable efficiency at eliminating the heavy metals.With increasing surfactant concentrations,removals of Pb,Cd and Zn increased significantly.High concentration Tween-80 solution had better extracting efficiency.The extraction efficiency of Tween-80 was found to be in the order: Cd>Zn>Pb,and the best efficiency was 83.07%,56.78%,42.57% respectively.The efficiency of LAS was low at low concentrations.Availabilities of Zn,Cd increased initially and decreased afterward,availability of Pb increased with increasing LAS,availabilities of Zn,Cd increased first and then decreased,availability of Pb decreased with increasing Tween-80 concentration.