ゼオライト膜の合成と分離性能

概要

論文の詳細を見る
Zeolite and molecular sieves are know to be very useful materials for catalysis, ion exchange and adsorption. Recently, great interest has been focused on zeolite membranes due to their uniform pore sizes and resistance to high temperatures. The membranes are also interesting from the standpoint of understanding of growth process of zeolite crystals. As the Al distribution and the change in morphology along the width of membrane reflect the time course of the crystal growth, we can get much information regarding the crystal growth process by analyzing the membrane obtained. Based on the results obtained, it was found that the polycrystalline zeolite membranes are formed through a successive accumulation of zeolite crystals and that during the initial crystallization of zeolite, the zeolite crystals with the high SiO2/Al2O3 ratios are generated. The liquid separation potential of the polycrystalline silicalite membranes prepared on porous sintered stainless steel and alumina supports was investigated using various alcohol/water mixtures by pervaporation. The membrane showed a high alcohol permselectivity, although there were pores of ca. 1 nm diameter, which were originated from crystal grains, other than intrinsic silicalite pores of ca. 0.6 nm within the membrane. Adsorption experiments of water and alcohols suggest that the high alcohol permselectivity is attributable to the selective sorption of alcohol into the membrane.