Extraction of heavy metals from a contaminated soil by reusing chelating agent solutions

We have studied ion-exchange in order to reuse aqueous solutions of chelating agents for trace-metals extraction from a contaminated soil. Amberlite IRC 748 resin was used to remove Cu2+, Ni2+ and Pb2+ from chelates in soil extracts and recover the chelating agents for reuse. Several ligands were studied for recovery, metal extraction efficiency and selectivity during successive washing cycles in column experiments. The results showed that the reused extracting solutions made with IDSA (iminodisuccinic acid) kept their extraction efficiency after 4-runs. No loss of ligand was detected, while metal extractions ranged between 80 and 97% at pH 7.0–7.6.