Hybrid brominated sulfonated poly(2,6-diphenyl-1,4-phenylene oxide) and SiO2 nanocomposite membranes for CO2/N-2 separation

Brominated sulfonated poly(2,6-diphenyl-1,4-phenylene oxide) (BSPPO) was synthesized as a new membrane material for CO/N separation. The 90% brominated-10% sulfonated PPO (BSPPO9010) was selected as representative material for membrane preparation. It formed flexible membranes with higher CO permeability (PCO = 58 Barrer) and selectivity (αCo/N = 36) than poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) membranes. BSPPO9010 membranes containing silica nanoparticles enhanced CO permeability while maintaining the CO/N selectivity as compared with the pure BSPPO9010 membranes. The CO permeability increased as a function of the silica content in the membrane. The separation mechanism for CO/N in the membranes was attributed to the gas solubility effect rather than the gas diffusivity