In this study composite mixed matrix membranes containing hydrophilic microphase-separated block copolymer (Pebax® 1657) and graphene oxide nanosheets were prepared using a dip coating method. Water vapor and N2 gas permeation were measured as a function of different parameters: (i) layer thickness, (ii) content of graphene oxide (GO), and (iii) content of reduced GO. Surprisingly, a concentration of only 2 wt% of GO nanosheets well dispersed in the Pebax layer boosted the selectivity 8 times by decreasing the water vapor permeance by only 12% whereas N2 gas permeance decreased by 70%. Using reduced GO instead, the water vapor permeance declined by up to 16% with no influence on the N2 gas permeance. We correlated the permeation properties of the mixed matrix membranes with different models and found, that both the modified Nielsen model and the Cussler model give good correlation with experimental findings

Thin film composite membranes were prepared using the blends of graphene oxide and an ionic liquid for efficient CO₂gas capture.

Polybenzimidazole (PBI), a thermally and chemically stable polymer, is commonly used to fabricate membranes for applications like hydrogen recovery at temperatures of more than 300 °C, fuel cells working in a highly acidic environment, and nanofiltration in aggressive solvents. This report shows for the first time the use of PBI dense membranes for water vapor/gas separation applications. They showed an excellent selectivity and high water vapor permeability. The incorporation of inorganic hydrophilic titanium-based nano-fillers into the PBI matrix further increased the water vapor permeability and water vapor/N₂ selectivity. The most selective mixed matrix membrane with 0.5 wt% loading of TiO₂ nanotubes yielded a water vapor permeability of 6.8 × 10⁴ barrer and a H₂O/N₂ selectivity of 3.9 × 10⁶. The most permeable membrane with 1 wt% loading of carboxylated TiO₂ nanoparticles had a water vapor permeability of 7.1 × 10⁴ barrer and a H₂O/N₂ selectivity of 3.1 × 10⁶. The performance of these membranes in terms of water vapor transport and selectivity is among the highest reported ones. The remarkable ability of PBI to efficiently permeate water versus other gases opens the possibility to fabricate membranes for the dehumidification of streams in harsh environments. This includes the removal of water from high temperature reaction mixtures to shift the equilibrium towards products.