Experiments showed that EDTA has most effectiveness in removing heavy metals from both contaminated soils; however, EDTA is relatively expensive and cannot be readily degraded by conventional biological treatment processes. Thus, EDTA may be recycled and reused. Species distributions of heavy metals in the extraction solutions were analyzed with MINTEQA2 computer programme at working condition, metal-EDTA was found to be predominant fractionation among metal species. Metals and EDTA were separated efficiently by Na2S addition from the extraction solution. After that, the recycled EDTA was reus...
