The sequential use of washing and an electrochemical reduction process for the remediation of lead-contaminated soils.

A two-step method for the remediation of three different types of lead (Pb)-contaminated soil was evaluated. The first step included soil washing with ethylenediaminetetraacetic acid (EDTA) to remove Pb from soils. The washing experiments were performed with 0.05 M Na2EDTA at 1:10 soil to liquid ratio. Following the washing, Pb removal efficiency from soils ranged within 50-70%. After the soil washing process, Pb2+ ions in the washing solution were reduced electrochemically in a fixed-bed reactor. Lead removal efficiency with the electrochemical reduction at -2.0 V potential ranged within 57-76%. The overall results indicate that this two-step method is an environmentally-friendly and effective technology to remediate Pb-contaminated soils, as well as Pb-contaminated wastewater treatment due to the transformation of toxic Pb2+ ions into a non-hazardous metallic form (Pb(0)).