有机酸与表面活性剂联合作用对土壤重金属的浸提效果研究

重金属污染土壤的原位淋洗修复既要实现对重金属的高效去除,还要尽量减少对土壤性质的破坏,这一点在农业污染土壤修复中尤为重要。以张士污灌区农田土壤为研究对象,利用振荡浸提技术筛选有机酸和表面活性剂组合,并确定了两者联合淋洗修复污染土壤的最佳配比。结果表明：有机酸（酒石酸、乙酸、柠檬酸和苹果酸）中的酒石酸浓度为0.5 mol.L-1和表面活性剂（SDBS、鼠李糖和皂素）中的皂素质量分数为0.7%时对土壤Cd、Pb、Zn的浸提效果较好;在酒石酸与皂素体积配比为1∶1时,对重金属Cd、Pb、Zn浸提效果最好,浸提率分别为87.62%、36.30%、20.67%;单一有机酸、表面活性剂或者有机酸与表面活性剂的混合溶液,对土壤重金属的浸提效果均为Cd〉Pb〉Zn。虽然有机酸与表面活性剂联合浸提效果略低于酒石酸浸提,但其弱酸性对土壤性质影响较小,在原位淋洗修复工程中有较好的应用前景。

Study on the extractive effect of soil heavy metals with organic acids and surfactants

It is necessary for removal of the heavy metals by leaching in-situ to both high efficiency and less destruction of soil properties,which is particularly important to remediation of contaminated agricultural soil.In case of the contaminated soil samples from Zhangshi sewage irrigation region,this paper screened the combination of the organic acids and surfactants by oscillating extraction and identified the best ratio of them.The results showed that the tartaric acid and saponin were of the best effect for extraction the Cd,Pb,and Zn.The best concentration were 0.5 mol·L-1 for tartaric acid,0.7% for saponin respectively,the best volume proportion was 1∶1,and the extraction rate were 87.62%,36.30%,20.67% respectively;whether of the single organic acid,surfactant or the mixture of organic acid and surfactant,the extraction ratio of the heavy metals were all CdPbZn.The effect of organic acid and surfactant joint leaching slightly below the tartaric acid leaching,but the weak acid was little affected the soil properties,and would have better prospects for the in-situ remediation of HMs contaminated soils by leaching.