Separation of butane and xylene isomers with MFI-type zeolitic membrane synthesized by a vapor-phase transport method

MFI-type zeolitic membranes were prepared by a vapor-phase transport (VPT) method on porous α-alumina flat disks. Single- and mixed-gas permeation measurements of butane isomers were performed in the temperature range of 300–375 K. The separation factor was always greater than the ideal selectivity. This result is explained by the preferential adsorption of n-butane on MFI in the binary system. The pervaporation tests for xylene isomers were performed at 303 K. p-Xylene was the most permeable component in the unary system. In the permeation measurements of a binary mixture of p-xylene/m-xylene and a ternary mixture of p-xylene/m-xylene/o-xylene, p-xylene predominantly permeated in the early stage, and then, the flux of p-xylene decreased gradually and finally became lower than that of the other xylene isomers. The adsorption of m-xylene in the pores of MFI seemed to block the permeation of p-xylene.