Arsenic Removal from Contaminated Soil Inside Non-Ferrous Metal Smelter by Washing

摘要

Orthogonal and single-factor experiments were used to investigate the remediation effect of single and mixed washing on arsenic-contaminated soil from a typical non-ferrous metal smelter. The optimal washing conditions, washing kinetics and speciation distribution of arsenic were determined. The obtained removal efficiencies of arsenic in the soil is 83.65%, which could be remedied to less than " risk intervention values (As < 140 mg.kg(-1)) for soil contamination of the development land" in soil environmental quality standard China (GB36600-2018) when the mixed ratio of Citric acid (1 mol.L-1) & Rhamnolipid (1%) is 2:1, the ratio of liquid-solid is 15:1 and the washing time is 393 min. The repair effect of mixed washing was significantly higher than the single washing agents, and the washing kinetics was a heterogeneous diffusion process, which was consistent with Elovich model. In addition, mixed washing agents can effectively remove active and potential bioavailable arsenic from soil, which greatly reduces their bioavailability and environmental risk.