Abstract: A porous composite structure, and in particular a membrane, for separating fluids is described. The composite structure comprises at least a porous support and a zeolite layer applied to the support and the zeolite is a zeolite of the T type or of an erionite type.

Abstract: There is provided a process for producing an acid-resistant membrane for separating a mixture, which is used for separation of a liquid and/or gas mixture by pervaporation, vapor permeation etc. The process for producing a membrane for separating a mixture comprises a step of carrying seed crystals of T-type zeolite on a porous support; a step of stirring an aqueous mixture containing a silica source, an alumina source, sodium ions, and potassium ions as the starting materials and then aging the mixture for a predetermined time and a step of immersing the porous support carrying the seed crystals in the aged mixture and then subjecting it to hydrothermal reaction to deposit T-type zeolite on the porous support. There can be provided the separation membrane on which chemical resistance such as acid resistance and alkali resistance as well as durability besides the molecular sieve ability of zeolite itself have been conferred.