Pervaporation and Vapor-Permeation Separation of Gas-Liquid Mixtures and Liquid Mistures by SAPO-34 Molecular Sieve Membrane Prepared in Dry-Gel Process

A method for the pervaporation or vapor-permeation separation of a gas-liquid mixture or a liquid mixture by a SAPO-34 molecular sieve membrane prepared in a dry gel process, characterized in that the method comprises the following steps;

• 1) mixing and dissolving an Al source, tetraethylammonium hydroxide (TEAOH), water, a Si source and a P source to make a reaction liquor for seeds, which is then subjected to crystallization for 2-72 h by heating at 120-230 ±C, then centrifuging, washing and drying to get SAPO-34 molecular sieve seeds;
• wherein the molar ratio of the Al source, P source, Si source, tetraethylammonium hydroxide and all water in the reaction liquor for seeds is 1 Al2O3:
• 1-2 P2O5:
• 0.3-0.6 SiO2:
• 1-3 TEAOH:
• 55-150 H2O;
• 2) coating the SAPO-34 molecular sieve seeds on a porous ceramic support;
• 3) uniformly mixing an Al source, a P source, a Si source, tetraethyl ammonium hydroxide (TEAOH) and water to form a mother liquor for dry gel synthesis of SAPO-34 molecular sieve membrane;
• wherein the molar ratio of the Al source, P source, Si source, tetraethyl ammonium hydroxide and all water in the mother liquor for dry gel synthesis is:
• 1 Al2O3:
• 1-2 P2O5:
• 0.1-0.6 SiO2:
• 1-8 TEAOH:30-1000 H2O;
• 4) supporting the mother liquor for dry gel synthesis on the porous support coated with SAPO-34 molecular sieve seeds prepared in step 2), and drying, to form a porous support having a dry gel layer;
• 5) placing the porous support prepared in step 4) into a reaction vessel, adding a solvent, performing crystallization of the dry gel;
• 6) calcining at 400-600° C. for 4-8 h to obtain a SAPO-34 molecular sieve membrane;
• 7) using the SAPO-34 molecular sieve membrane obtained in step 6) to perform the separation of a liquid mixture by a process of pervaporation separation or vapor-permeation separation;
• wherein the liquid mixtures is a mixture of methanol and a liquid other than methanol, wherein said liquid other than methanol is selected from one of dimethyl carbonate, ethanol, methyl tert-butyl ether;