Promoting the electrochemical and Separation properties of heterogeneous cation exchange membrane by embedding 8-hydroxyquinoline ligand: Chromium ions removal

In this probe, an attempt was made to remove the chromium ions using heterogeneous cation exchange membrane (HCEM) incorporated with 8-hydroxyquinoline (8-HQ) ligand as the chelating agent. Composite cation exchange membranes were provided by utilizing solution casting method. Computational study of resin particle and 8-HQ molecule also has been performed in order to accomplish detailed evaluation of their reactive properties. Molecular electrostatic potential (MEP) of 8-HQ molecule and resin particle showed that both particles have appropriate reactive sites for electrophilic and nucleophilic attack. Furthermore, interaction energy between 8-HQ molecule and resin particle were calculated which confirmed the presence of strong interactions between them. Elemental mapping, scanning electron microscopy (SEM), and scanning optical microscopy (SOM) images of the resultant membranes indicated a relatively uniform surface and particles distribution. Membrane water uptake and surface hydrophilicity were enhanced in the attendance of 8-HQ. The blended membranes demonstrated better selectivity (up to 95.5%), lower electrical resistance (similar to 5.8 Omega.cm(2)) and better ionic permeability compared to the bare one whereas the selectivity and electrical resistance of unmodified sample measured 77% and 14 Omega.cm(2), respectively. The ligand modified membranes showed more dialytic rate in chromium ions removal (up to 74%) compared to bare membrane which could be assigned to strong affinity of 8-HQ in heavy metal ions adsorption.