Surface modification of mesoporous membranes by fluoro-silane coupling reagent for CO2 separation

The potential of hybrid organic–inorganic membranes for separating organic molecules from air, based on solubility selective mechanism, was evaluated. Alumina and titana membranes with average pore size near 4 nm were surface modified using trimethoxysilane fluorinated coupling reagent. The permeabilities to helium, nitrogen, methane, ethane, propane, butane and carbon dioxide were evaluated at feed pressures lying between (1.5 × 105 and 3.5 × 105 Pa) 1.5 and 3.5 bar and permeate outlet near 1 × 105 Pa (1 bar). The permeabilities of the grafted membranes generally decreased by about two to three orders of magnitude compared with the untreated membranes. The CO2/N2 permselectivity increased significantly in the case of the TiO2 grafted membrane. The membranes performances were compared and the TiO2 grafted membrane exhibits higher permselectivity and permeability, so that, it is a good candidate for CO2 to N2 separation and CO2 to hydrocarbon separation.