Orthogonal and single factor experiments were used to investigate the remediation effect of single and compound washing on Pb contaminated soil from a typical non-ferrous metal smelter. The optimal washing conditions and speciation distribution of Pb were determined. The obtained removal efficiency of Pb from the soil is 68.35%, which could be remedied to less than "risk intervention values (Pb 2500mg·kg-1 ) for soil contamination of the development land" in soil environmental quality standard China (GB36600-2018) when the compound ratio of HCl & Rhamnolipid is 1:1, the ratio of liquid-solid is 10:1 and the washing time is 1080 min. The removal efficiency of Pb are significantly higher when using compound eluents compared to single eluents, such as HCl, EDTA, oxalic acid and rhamnolipid. Moreover, compound eluents can effectively remove active Pb from soil, which greatly reduces their bioavailability and environmental risk.
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