Effect of substrate curvature on microstructure and gas permeability of hollow fiber MFI zeolite membranes

Literature data show that gas permeability of MFI zeolite membrane varies depending on the geometry of supports. The present work investigates the effects of the surface curvature of substrates on the microstructure and the gas permeation property of supported zeolite membranes. MFI zeolite membranes were grown on porous alumina hollow fibers with different diameters (surface curvature) by the secondary growth method. Single gas permeation and H-2/CO2 binary gas separation from 25 to 300 degrees C were conducted to study the membrane quality. The zeolite membranes on supports of larger surface curvature have higher permeability and lower selectivity due to the presence of more inter-crystalline gaps in the zeolite layer formed during the template removal step. The effects of the support surface curvature (and geometry) on zeolite membrane microstructure and gas permeation characteristics are semi-quantitatively analyzed by a transport model considering both structural change and gas diffusion in micropores. (c) 2018 American Institute of Chemical Engineers AIChE J, 64: 3419-3428, 2018