Separation of Heavy Metal Ions with a Chelating Reagent Fixed in an Anion-exchange Membrane

The precipitation treatment of waste water of heavy metal ions as hydroxides is not efficient when their concentrations are very low. We propose a novel method to separate heavy metal ions with ethylenediaminetetraacetic acid (EDTA) fixed in an anion-exchange membrane. Cation-exchange membranes were placed at both sides of the membrane to avoid the desorption of the reagent by the ion-exchange with the co-ion in the solutions. Heavy metal ions in the source phase solution was selectively transported to the receiving phase of acid solution via the complexation with EDTA fixed in the anion-exchange membrane.