Improving separation performance of high-silica zeolite membranes by surface modification with triethoxyfluorosilane

摘要

Treatment with triethoxyfluorosilane (TEFS) enhances the hydrophobic properties of high-silica MFI and MEL membranes synthesized by a microwave-assisted secondary growth method. The modified membranes showed significant improvement in recovery of ethanol from ethanol/water mixtures by pervaporation. The TEFS treatment was also able to heal some intercrystalline defects in the zeolite membrane film. Additional physical-chemical characterization revealed that the external zeolite surface is selectively covered by the organosilane without blocking zeolite micropores. The grafted Si-F moieties are thermally and hydrothermally stable.