Electroextraction of heavy metals from diluted solutions by a process combining ion-exchange resins and membranes

The electroextraction of heavy metals (Pb2+, Cu2+, Zn2+ and Cd2+) from diluted solutions was achieved by continuous electropermutation combining ion-exchange resins and membranes. Under an applied current, the metallic cations fixed onto the resin are substituted by protons coming from the anodic compartment, and are transferred into a receiver compartment, at the cathodic side, where they are concentrated. Electroextraction operations were performed under various experimental conditions of current density (2-7 A m−2), flow rate (0.09-0.9 dm3 h−1), cation concentration (40-400 mg dm−3) and nature of regenerating acid solutions (HNO3, HCl, H2SO4). Despite the resins were loaded with the metallic cations before introducing in the feed compartment of the cell, high levels of removal (up to 99%) were achieved. High mass transfer was obtained leading to a concentration factor of about five in the receiver.