Assisted Electromigration of Bipolar Ions through Ion-Selective Membranes in Glycine Solutions

At current densities above the limiting diffusion currents in electromembrane systems, bipolar ions of amino acids react with protons or hydroxyl ions that form during irreversible dissociation of water molecules at membrane–solution interfaces, convert into cations or anions, and then, after a gradient of electric potential is imposed on the system, migrate through cation-selective or anion-selective membranes (assisted electromigration). This phenomenon makes it possible to effectively separate solutions containing bipolar ions and nonelectrolyte molecules using electrodialysis with alternate cation-exchange and anion-exchange membranes.