为探索不同清洗剂对铅蓄电池厂区内铅污染土壤的去除效果及铅在不同粒径土壤清洗过程中的行为,本研究通过设定清洗剂的浓度梯度,对土样粒径分级、设定清洗时间等方法进行研究。结果显示EDTA和EDDS对铅具有最佳去除率(B点土107.19%和96.49%);盐酸对A点土最佳铅去除率为49.57%,B点、C点土在99.03%和89.93%;柠檬酸对3点位土的铅去除率最大为39.51%;鼠李糖脂对3份土铅去除率均低于10%。EDTA和EDDS在高浓度铅的去除中表现优势;柠檬酸适合去除中低浓度铅;盐酸的使用需考虑土壤本身情况。粗沙粒和细沙粒中的铅去除率高,粉粘粒的铅去除率低;最佳清洗时长为240min。此外,土壤本身理化性质对清洗剂效果的发挥有影响,清洗剂浓度过高可能降低清洗效率。该研究可为铅污染土壤清洗技术提供科学依据。
To explore the lead removal of different washing agents for soil polluted by lead in lead battery factory and the lead behavior during washing process in soils with different sized particles, this paper studies the size grading of the soil particles and setting the washing time based on setting different concentration gradient of washing agents. The results show that the optimal lead removal rates of EDTA and EDDS are 107.19% and 96.49% respectively for the soil at site B; and that of hydrochloric acid for soils at point A, B and C are 49.57% , 99.03% and 89.93% ; for soils at the three point, the highest remove rate of citric acid is 39.51% , while all the three removal rates of rhamnolipid are less than 10% ; EDTA and EDDS performances show advantage in soil polluted by high concentration lead; citric acid is suitable for soil with medium or low lead concentration; application of hydrochloric acid should consider the soil situation. The lead removal rates are high for coarse sands and fine sands, but low for the silt soil; the optimum washing time is 240 minutes. In addition, the physical and chemical properties of soil affect the washing performance, and over high washing agent concentration may reduce the efficiency. This study provides scientific basis for the technology of washing soil polluted by lead.