New approach to adapting electrochemical properties of cation-exchange membrane by incorporating tris(8-hydroxyquinolinato)aluminum nanoparticles

摘要

Electrodialysis-mixed matrix tris(8-hydroxyquinolinato)aluminum (AlQ(3)) nanoparticles entrapped heterogeneous cation-exchange membrane was prepared by the solution casting technique. The effect of the concentration of AlQ(3) in the casting solution on the physico-chemical properties of the homemade membranes was studied. AlQ(3) nanoparticles were synthesized via a simple precipitation method and characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction. The use of AlQ(3) nanoparticles in the membrane matrix led to an increase of the membrane electrical conductivity and surface hydrophilicity. The membrane ion-exchange capacity was enhanced by using AlQ(3) loading ratios up to 1.5wt%; the IEC decreased for concentrations above 1.5wt%. The increase of AlQ(3) content ratios up to 0.5wt% in fabricated membrane initially caused to increase of water content. The membrane water content was decreased for the concentrations between 0.5 to 1.5wt% and then showed an increasing trend again at higher additive loading ratios. The membrane potential, charge density, permselectivity, and transport number were improved obviously by the use of AlQ(3) nanoparticles in membrane body. The ion flux/permeability enhanced sharply by using of AlQ(3) up to 0.5wt% in the membrane matrix and then began to decrease while the additive concentration was more than 0.5wt%.