References(21) Cited-By(19) MFI-type zeolite membranes were synthesized by hydrothermal reaction on the surface of porous α-alumina support tubes with different pore sizes. The zeolite membranes consisted of three zones: The top zone was a polycrystalline zeolite layer and the inner zone was a layer of α-alumina macropores, partially filled with deposits. The intermediate zone was a mixture of alumina particles and deposits. The morphology of the zeolite membranes was dependent on the substrates. The permeance of zeolite membranes formed on the substrate possessing pores of 150–170 nm under identical conditions ranged over two orders of magnitude. There was no definite relationship between n-butane/i-butane (n-C4H10/i-C4H10) permselectivity and permeance, although permeance was affected by the substrates. The n-C4H10/i-C4H10 permselectivity calculated from single-component permeances was in the range of 1.5~12 at 100°C, and the activation energy for the permeances was 11 kJ·mol-1. The selectivity increased in the case of n-C14H10 separation from a mixture containing a small amount of i-C4H10. The zeolite membranes thus served as molecular-sieving for C4 isomers.
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