High performance graphene-oxide doped cellulose acetate based ion exchange membrane for environmental remediation applications

This study illustrates the preparation of graphene oxide (GO) impregnated cellulose acetate (CA) ion exchange membrane (IEM). The compositional ratio of GO/CA/polyethylene glycol for preparing cation exchange membranes was optimised for ion exchange capacity (IEC), fixed charged density, water uptake, swelling degree and proton conductivity. Proton conductivity of 0.273 S cm−1 and IEC of 1.08 m mol/g at 30°C was obtained for the membrane with highest GO% (CAG3). The modified CAG3 membrane had better hydrophilicity with a contact angle of 53.4°. Based on the ion exchange property, the membrane was utilised to study the rejection behaviour of both cationic and anionic dyes along with its acid recovery performance in the presence of different salts. It was observed for highest GO-incorporated membrane CAG3 that the acid recovery increased to 61% (1.78 × 102 moles H+ ions/m2h). Low rejection rate for cationic dye (~20%) and high rejection for anionic dye (~92.5%) was obtained. The selective higher rejection of anionic dye along with better acid recovery confirms the formation of a better IEM with enhanced proton conductivity. Furthermore, on analysing for real-life water samples, obtained results showed that the rejection percentage and H+ ion molar flux rate decreased to 1.7% and 17.4%, respectively.