Electrodialysis heterogeneous anion exchange membrane modified by PANI/MWCNT composite nanoparticles: Preparation, characterization and ionic transport property in desalination

In this research polyaniline (PANI)-co-multi walled carbon nanotubes (MWCNTs)/polyvinylchloride (PVC) nano-composite heterogeneous anion exchange membranes were prepared by solution casting technique. The effect of PANI/MWCNT nanoparticle concentration on membrane electrochemical properties was studied. Membrane water content was decreased by the increase of nanoparticle concentration. Ion exchange capacity (IEC) was improved initially by the increase of nanoparticle concentration up to 2 wt.% and then showed decreasing trend by more additive content from 2 to 4 wt.%. IEC was enhanced again with more increase in additive concentration from 4 to 16 wt.%. Fixed ionic concentration (FIC) also showed increasing trend by an increase in nanoparticle content. Membrane potential, transport number and selectivity were improved in NaCl and Na2SO4 ionic solutions by the increase of PANI/MWCNT nanoparticles. Also membranes exhibited lower selectivity and transport number for bivalent ions compared to monovalent type. Membrane permeability and flux were enhanced initially in both monovalent and bivalent ionic solutions by an increase in additive concentration up to 1 wt.% and then showed decreasing trends by more additive content from 1 to 16 wt.%. Prepared membranes showed lower permeability and flux for bivalent ions compared to monovalent type. Modified membranes showed better performance in comparison with pristine membrane.