Effect of solvent type on the morphology and gas permeation properties of polysulfone–silica nanocomposite membranes

In this study, the effects of various solvents on the structure and permeation properties of polysulfone–silica nanocomposite membranes were investigated. Silica nanoparticles were prepared by the sol–gel method through the hydrolysis and condensation of tetraethyl orthosilicate (TEOS). Polysulfone–silica nanocomposite membranes were prepared by the thermal phase inversion method. N-methyl pyrrolidone (NMP), N,N-dimethyl acetamide (DMAc) and tetrahydrofuran (THF) were used as solvents. Based on the experimental results, it was observed that the CO₂/N₂ and O₂/N₂ selectivities increased in the presence of silica nanoparticles in all cases. However, the permeabilities of the applied gases decreased, except for CO₂. Based on the obtained selectivity data, permeability data, and favorable dispersion of silica nanoparticles in the polymer matrix, the results indicate that NMP is the best solvent for polysulfone–silica membrane preparation. The obtained CO₂ permeability and CO₂/N₂ selectivity of the polysulfone–silica (5 wt%) membrane prepared using NMP as the solvent were 7 barrers and 35, respectively.