Hybrid brominated sulfonated poly(2,6-diphenyl-1,4-phenylene oxide) and SiO2 nanocomposite membranes for CO2/N2 separation

Brominated sulfonated poly(2,6-diphenyl-1,4-phenylene oxide) (BSPPOdp) was synthesized as a new membrane material for CO2/N2 separation. The 90% brominated-10% sulfonated PPOdp (BSPPOdp9010) was selected as representative material for membrane preparation. It formed flexible membranes with higher CO2 permeability (PCO2=58 Barrer) and selectivity (αCO2/N2=36) than poly(2,6-dimethyl-1,4-phenylene oxide) (PPOdm) membranes. BSPPOdp9010 membranes containing silica nanoparticles enhanced CO2 permeability while maintaining the CO2/N2 selectivity as compared with the pure BSPPOdp9010 membranes. The CO2 permeability increased as a function of the silica content in the membrane. The separation mechanism for CO2/N2 in the membranes was attributed to the gas solubility effect rather than the gas diffusivity.