Improvement of hydrogen-separating performance by on-stream catalytic cracking of silane over hollow fiber MFIÂ zeolite membrane

MFI zeolite membranes were synthesized on porous α-alumina hollow fibers by in-situ hydrothermal synthesis. The membranes were further modified for H2 separation by on-stream catalytic cracking deposition of methyldiethoxysilane (MDES) in the zeolitic pores. The separation performance of the modified membranes was characterized by separation of H2/CO2 gas mixture at 500 °C. Activation of MFI zeolite membranes by air at 500 °C was found to promote catalytic cracking deposition of silane in the zeolitic pores effectively, which resulted in significant improvement of H2-separating performance. The H2/CO2 separation factor of 45.6 with H2 permeance of 1.0 × 10−8 mol m−2 s−1 Pa−1 was obtained at 500 °C for a modified hollow fiber MFI zeolite membrane. The as-made membranes showed good thermochemical stability for the separation of H2/CO2 gas mixture containing H2O and H2S, respectively.