高粘性土壤中重金属的洗涤效果初探

Discussion on Heavy Metals Removal Efficiency in Clay by Soil Washing

利用三氯化铁(FeCl_3)、草酸和十二烷基磺酸钠(SDS)3种淋洗剂对典型高粘性重金属污染土壤进行淋洗处理,考察淋洗剂浓度、淋洗时间和淋洗次数对重金属去除效率的影响。当浓度为0.1 mol/L时,Fe Cl3对土壤中Cu、Pb、Zn、Ni和Cr的去除率分别为63.4%、22.8%、17.5%、37.9%和10.0%,草酸对重金属的去除率分别为52.7%、0%、19.6%、20.6%和3.3%,SDS对重金属的去除率分别为2.8%、13.6%、2.5%、9.8%和10.2%。重金属的去除率在1 h内即达到相对平衡,重金属的淋洗去除作用在4 h内随着时间的增加并未发生明显变化。淋洗3次后,Fe Cl3可以去除土壤中超过95%的Cu和Ni,对于Pb的去除率也较高,超过70%,草酸对Cu和Zn具有良好的去除效率,SDS对重金属的去除效果较差。

The removal efficiency of heavy metals by soil washing in the contaminated clay was investigated using ferric trichloride(FeCl_3),oxalic acid and sodium dodecyl sulfonate(SDS).The influence of washing reagent concentration,time and washing frequency on the removal efficiency were discussed.Cu,Pb,Zn,Ni and Cr were removed by 63.4 %,22.8%,17.5%,37.9% and 10.0% with FeCl_3,52.7%,0%,19.6%,20.6% and 3.3% by oxalic acid and 2.8%,13.6%,2.5%,9.8% and 10.2% with SDS,respectively.The removal efficiency was not increased significantly after 1 h.After washing 3 times using single reagent,more than 95% of Cu,Ni and 70% of Pb was removed by FeCl_3.Oxalic acid was helpful to the removal of Cu and Ni,and the removal efficiency of heavy metals washing by SDS was very low.