Surface modification of mesoporous membranes by fluoro-silane coupling reagent for CO_2 separation

摘要

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 x 10~5 and 3.5 x 10~5 Pa) 1.5 and 3.5 bar and permeate outlet near 1 x 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 CO_2/N_2 permselectivity increased significantly in the case of the TiO_2 grafted membrane. The membranes performances were compared and the TiO_2 grafted membrane exhibits higher permselectivity and permeability, so that, it is a good candidate for CO_2 to N_2 separation and CO_2 to hydrocarbon separation.