Feasibility Assessment of Soil Washing Using Oxalic Acid and Potassium Iodide for Restoration of Agricultural Soil Contaminated by Arsenic and Mercury

In this study, we investigated the feasibility of a soil washing method that does not require a physical separation (PS) process in remediating agricultural soil contaminated by arsenic and mercury.Oxalic acid and potassium iodide (KI) were used as washing solutions to remove arsenic and mercury, respectively.Particle sorting by grain size and subsequent washing eliminated at least 80% of the contaminants.The removal capacity of clayey soil grains was 87%, and the same result was observed even when soil sieving was not performed prior to washing.The overall results suggest that soil washing using oxalic acid and KI, without PS, has potential applicability as a remediation method for agricultural soils.Further research on the sequential washing step between the two solutions is required to realize a detailed soil cleanup design.