Removal of copper, lead and zinc from artificially contaminated soil samples using EDTA, rhamnolipids, and soapnut in batch experiments

The feasibility of the removal of Cu, Pb and Zn from sandy loam soils was investigated in laboratory-scale batch experiments, using soapnut, rhamnolipids, and EDTA (ethylenediamine tetraacetate) as washing agents. Influencing parameters, including the concentration and pH of the washing solutions, soil-solution ratios (weight of soil sample/volume of the washing solution) and washing times, were studied. It was observed that removal efficiencies were influenced by the concentration of the washing solution, pH, soil-solution ratio, and washing time as well as by the addition of EDTA. While an increase in the concentration of the washing solution, soil-solution ratio, washing time and addition of EDTA increases the removal efficiency, an increase in pH of the washing solution decreases the removal efficiency. The results indicate that the heavy metal removal efficiency almost approached a plateau, at pH 3, a soil-solution ratio of 40, a concentration of 3%, and a washing time of 24 h.