Preparation of Faujasite-Type Zeolite Membrane for Alcohol Dehydration

Conventional production processes involve distillation towers for dehydration of products such as a wide variety of alcohol, which consume a large amount of energy. Combination of a membrane separation unit with distillation can drastically reduce energy demand for the dehydration of alcohols. Faujasite-type zeolite, which is known as zeolite X and Y, is a kind of zeolite with both high stability and strong hydrophilic nature. We investigated the preparation method of a compact faujasite-type of zeolite membrane, and separation properties were examined for mixtures of isopropanol(IPA)/water system. Faujasite-type membranes were prepared on the outer surface of tubular porous alumina support by a secondary-growth method. Vapor permeation and separation measurements were performed using a stainless steel tube module cell. The effective membrane area was 6.28 cm². The faujasite-type membrane highly separated water from water/IPA mixtures. In the case of an mixture of water/IPA (50/50 wt/wt), the flux of water was 5x10^-7 mol m^-2 s^-1 Pa^-1 and the separation factor of water/IPA exceeded 840 at steady state at 373 K. Further development was carried out on the basis of detailed studies on the control of seeding process and crystal growth.