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

Pebax-1657 nanocomposite membranes incorporated with nanoparticles/colloids/carbon nanotubes for CO2/N-2 and CO2/H-2 separation

Pebax-1657 is known as a promising polymeric membrane material for CO /N and CO/H separation. In order to further improve its gas separation performance and reinforce the membrane, different fillers including silica nanoparticles, polystyrene (PS) colloids, and carbon nanotubes (CNTs) were incorporated into the polymer matrix to form nanocomposite membranes. The nanocomposite membranes of Pebax-1657/silica and Pebax-1657/PS colloid had a decreased CO permeability and selectivity over N or H compared to the pure Pebax-1657 membrane, while the Pebax-1657/CNT nanocomposite membranes had an increased CO permeability, retaining similar CO/N or CO/H selectivity compared to the pure polymer membrane. The CO permeability increased with increasing CNT content and reached a maximum at 5 wt % CNTs. The CNT-enhanced gas permeability was attributed to the increase in gas diffusivity. The tensile modulus of Pebax-1657 increased 43% after adding 5 wt % single-wall CNTs (SWNTs), and increased 24% after adding 5 wt % multi-wall CNTs (MWNTs). Thus, it is feasible to add CNTs to Pebax-1657 membranes for improved mechanical strength and gas separation performance