Synthesis and Characterization of Cation Exchange PVA-g-PAA/PBI sulfone Membrane for the Electrolysis of Sodium Chloride

The reported work is on the preparation and characterization of polyvinyl alcohol -g- Polyacrylic acid (PVA-g-PAA)/ Polybenzimidazole sulfone (PBIs) cation exchange membrane used for the electro dialysis of sodium chloride solution. The polymer syrup has been prepared using the grafting method with the help of polyvinyl alcohol and polyacrylic acid in the presence of water solvent. The polymer syrup is casted on a porous ceramic support to prepare a non-interpenetrating graft membrane in order to provide the sufficient mechanical strength. The composite membrane is modified by the PBI sulfone to introduce sulfonate charges on its surface. The prepared membrane is specific to the transport of sodium (Na+) ions through its pores as by the migration mechanism. The modification effect is confirmed by SEM, FTIR, water uptake capacity, contact angle measurement, ion exchange capacity and current- voltage curve for the requirement of limiting current density. The electrolysis results of sodium chloride solution were reported in terms of current efficiency and energy consumption for sodium hydroxide production. The various operating parameters like salt concentration, current density, and circulation rates have an effect on the current efficiency which has been studied. It was observed that with an increase in salt concentration and flow rate, the current efficiency increased significantly. The maximum current efficiency which was obtained is 95.2% and the corresponding power consumption is 0.1224 kWh/ mol at 2N salt concentration and current density of 254 A/m2.