Improving electrochemical properties of cation exchange membranes by using activated carbon-co-chitosan composite nanoparticles in water deionization

In this study, the influence of various weight ratios of activated carbon (AC)-co-chitosan (CS) composite nanoparticles in the matrix of ion exchange membranes was examined to adapt their electrochemical characteristics based on the combination of high surface area and adsorptive property of activated carbon nanoparticles and the hydrophilicity and functionality of chitosan. Scanning electron microscopy (SEM), scanning optical microscopy (SOM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD), water content, ion exchange capacity (IEC), water contact angle, membrane potential, transport number and permselectivity, sodium flux, and membrane electrical resistance were used in membrane characterization. The fabricated membranes were also utilized in copper removal from water. The SEM and SOM images exhibited a uniform distribution of nanoparticles (NPs) on the surface of membranes. The membrane surface hydrophilicity was decreased; surface roughness and water content increased by utilizing AC-co-CS composite NPs. Membrane IEC was initially enhanced by utilizing composite NPs up to 0.5% wt and then decreased by more increase in additive ratios from 0.5 to 2%. Increasing trend was observed again at higher NPs concentration. Similar trend was also found for sodium flux. Membrane potential, t-number, permselectivity, and membrane electrical resistance initially represented an enhancing trend by use of AC-co-CS composite NPs up to 0.5% wt in membrane body and then decreased by more increase of NPs concentration from 0.5 to 8% wt. The fabricated membranes containing AC-co-CS nanoparticles showed good capacity in Cu removal from water. Membrane mechanical strength was improved initially by utilizing AC-co-CS composite NPs and then decreased at high additive concentration.