Process for preparing supported zeolitic membranes by temperature-controlled crystallisation

Abstract

A process is described for preparing a supported zeolite membrane constituted by a composite continuous zeolite/support layer of controlled thickness, wherein the zeolitic phase is principally localized in the pores of a porous support and optionally on the external surface thereof, the process comprising at least the formation of a precursor gel of the zeolite, bringing the gel into contact with the support and crystallizing the zeolite. The zeolite is crystallized by carrying out a thermal program comprising at least three steps in succession: a first constant temperature stage carried out at a temperature in the range 50° C. to 300° C., cooling to a temperature of strictly less than 50° C. followed by a second constant temperature stage carried out at a temperature range of 50° C. to 300° C. The prepared membrane is used in particular in processes for separating gas or separating liquids.

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