We demonstrate that b-oriented MFI (Mobil Five) zeolite membranes can be manufactured by in situ crystallization using an intermediate amorphous SiO2 layer. The improved in-plane growth by using a zeolite growth modifier leads to fusion of independent crystals and eliminates boundary gaps, giving good selectivity in the separation of CO2/Xe mixtures. The fast diffusion of CO2 dominates the overall membrane selectivity toward the CO2/Xe mixture. Because of the straight and short [010] channels, the obtained CO2 permeation fluxes are several orders of magnitude higher than those of carbon molecular sieving membranes and polymeric membranes, opening opportunities for Xe recovery from waste anesthetic gas.
Keywords: MFI zeolite membrane; anesthetic; carbon dioxide; gas separation; xenon.