Temperature resistant phosphorylated graphene oxide-sulphonated polyimide composite cation exchange membrane for water desalination with improved performance.

To achieve efficient water desalination/waste water treatment at high temperature, highly stable aliphatic/aromatic sulphonated poly(imide) (SPI)-phosphorylated graphene oxide (PGO) based temperature resistant cation exchange membranes (CEMs) were architected. The structural features: aliphatic connector between terminal end groups, direct grafting of sulfonic acid groups on aromatic rings, were responsible for their improved performance and stabilities. Data for Pristine (SPI) and composite (SPI/PGO) membranes suggested that membrane performance and stabilities were significantly improved with incorporation of PGO in the SPI matrix. Incorporation of PGO in the membrane matrix contributed towards mechanical, thermal and oxidative resistant nature, while presence of multi-ionic clusters (–SO 3 H & –PO 3 H 2 ) was responsible for hydrophilic ion conducting channels. Most suitable SPI/PGO-8 composite CEM (IEC: 2.37 mequiv g −1 ) exhibited 6.8×10 − 2 S cm −1 ionic conductivity and 0.96 t + m value and found to be promising candidate for electrodialytic water desalination. Further, significantly improved process performances (energy consumption and current efficiency) for water desalination by electrodialysis (ED) provides sustainable and feasible alternative for applying ED for salt separation in aqueous media at high temperature. [ABSTRACT FROM AUTHOR]