Electrodialysis Heterogeneous Anion Exchange Membranes Filled with TiO2 Nanoparticles: Membranes' Fabrication and Characterization

In the current research, polyvinylchloride based mixed matrix heterogeneous anion exchange membranes were prepared by a solution casting technique. Titanium dioxide nanoparticles were also utilized as inorganic filler additive in the membrane fabrication. The effect of TiO2 nanoparticles concentration in the casting solution on the membrane physico-chemical properties was studied. Membrane water content was decreased by an increase of nanoparticle concentration. Ion exchange capacity was also improved initially by an increase of nanoparticle content ratio and then slightly decreased. The membrane fixed ionic concentration, membrane potential, transport number and permselectivity were all increased by an increase of additive loading ratio. The membrane ionic permeability was enhanced initially by an increase of nanoparticle concentration up to 0.5 %wt in the membrane matrix and then decreased by more additive content ratio from 0.5 to 4 %wt. Membrane ionic resistance was declined by using TiO2 nanoparticles in the membrane matrix. Membranes also exhibited lower permselectivity and transport number for bivalent ions in comparison to monovalent ones. An opposite trend was found for the membrane ionic permeability. The amount of swelling in the homemade membranes was also less than 5% in thickness and negligible in length and width. Among the prepared membranes, the modified membrane containing 0.5 %wt TiO2 nanoparticles concentration showed more appropriate performance compared to the others. The obtained results revealed that modified membranes in this study are comparable with commercial membranes.