Surface Modification of Cation Exchange Membranes Using Chitosan-co-PANI/Graphene Oxide Nanocomposite Layer

Abstract

Hypothesis: The surface modification of polyvinylchloride-based heterogeneous cation exchange membranes was carried out using chitosan-co-polyaniline/graphene oxide nanocomposite layer for the application in electrodialysis process. Methods: The PANI/GO nanocomposites were prepared by in situ chemical oxidative polymerization of aniline in the presence of graphene oxide nanoplates. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), water content, flux and permeability, areal ionic resistance, water softening ability and fouling measurements were used to characterize the membrane.Findings: The FTIR analysis results and SEM images demonstrated successful formation of polyaniline on the graphene oxide nanoplates. The scanning electron microscope images of membranes also exhibited a uniform layer of chitosan-co-PANI/graphene oxide nanoplates on the membrane surface. The water content of modified membranes was higher than that of pristine membrane. The sodium flux and sodium permeability were improved about 20% by 0.1 %wt PANI/graphene oxide nanocomposite. The areal ionic resistance of modified membranes also showed a decreasing trend by utilizing composite nanoplates in the membrane matrix. The prepared membranes showed good ability for Ca and Mg removal from water. The removal efficiency of Ca and Mg by membrane containing 0.5 %wt PANI/graphene oxide composite nanoplates was, respectively, 61 and 79% during 15 min. Moreover, the pollutant and foulant formed on the membrane surface were totally removed by sonication technique. The modified membranes showed suitable electrochemical characteristics compared to membranes reported by other researchers and made by industries.

Keywords

• heterogeneous cation exchange membrane
• surface modification
• chitosan
• graphene oxide/polyaniline
• deionization