Permeability of zinc ions across ion-exchange membrane of ion-exchange electrodialyzer

Abstract

To evaluate the permeability of heavy-metal ions that exist as cation and anion species in seawater, we proposed a model equation that expresses the permeation rates of monovalent and divalent anions across an anion-exchange membrane using the permeation rates of Br − and SO 4 2−. The permeability of zinc across a cation- and an anion-exchange membrane was evaluated using the cation- and anion-model equations. We analyzed the permeation rates of zinc species ( E Z n 2 + , E ZnC l + , E ZnC l 3 − , E ZnC l 4 2 − ). We found that E ZnC l + and E Z n 2 + decreased with an increase in the concentration of chloride ions in the feed solution, indicating that E Zn(C) decreases with an increase in the concentration of chloride ions. Moreover, E ZnC l 3 − and E ZnC l 4 2 − increase with the concentration of chloride ions in the feed solution, indicating that E Zn(A) increases with the concentration of chloride ions.