Heavy metal removal from low permeable contaminated soils using ZVI permeable reactive barrier combined electrokinetics system

Heavy metals (HMs) removal from clay soils by conventional soil washing techniques is a challenging process due to the soil low permeability. In this study, removal of copper (Cu) from contaminated clay soil was investigated using electrokinetic (EK) technology coupled with zero-valent iron (ZVI) permeable reactive barrier medium (PRB). Reverse polarity (REK) and pH control (EK-pH) strategies were used to improve the EK performance. According to the result, for a constant electric field (۱.۰ V.cm-۱) applied during ۱۵ days, the pH control strategy (EK- pH) attained a high removal efficiency of ۸۳.۷% where the better soil conditions such as stable pH, highest EC (۸۵ mA) and EOF (۷.۹ mL/d) were observed. However, the best Cu removal efficiency of ۸۴.۳% was achieved in the case of polarity reversion (REK) due to the pH stability and equal water movement to the PBR from the two sides. The results of this work suggest a promising technique for effective heavy metal removal from contaminated soil.

Keywords:

Soil pollution , Heavy metal , Electrokinetic , ZVI , Permeable reactive barrier