Preparation of SAPO-34 molecular sieve film for selectively separating methane gas

Abstract

The invention relates to a novel method of SAPO-34 molecular sieve membrane for selectively separating methane gas by crystal guidance and secondary synthesis. The method includes three steps, namely synthesizing crystal seed, preparing basement membrane of crystal seed and synthesizing SAPO-34 molecular sieve membrane, in particular to the following steps: phosphoric acid, TEAOH and silica sol are added into adequately hydrolyzed aluminium isopropoxide to prepare a crystal seed solution of the molecular sieve and the molecular sieve composite mother solution; the crystal seed solution of the molecular sieve is prepared to be suspension after crystallization and rinsing for dripping onto a treated carrier; a basement membrane of crystal seed acquired is placed in a reaction kettle and is added with the molecular sieve composite mother solution for crystallization at a temperature ranging from 150 DEG C to 180 DEG C for 3 through 20 days, which is taken out for cleaning and drying and then is followed with actively removing a template agent at a temperature ranging from 400 DEG C to 600 DEG C. Synthesizing the molecular sieve membrane with the method of the invention is suitable for various porous supports with smooth surface, which is of high repetitiveness, good orientation, excellent separating property and ultrahigh gas permeability and is suitable for industrial application.

Description

technical field [0001] The invention belongs to the field of molecular sieve membrane preparation, and in particular relates to a preparation method of a SAPO-34 molecular sieve membrane for secondary synthesis and selective separation of methane gas induced by seed crystals. Background technique [0002] Membrane is an intermediate intervening phase that separates two phases of matter and makes them related to each other, and the process of mass and energy transmission occurs. Compared with well-known traditional separation methods, such as evaporation and fractionation, the membrane separation process has the outstanding advantages of high efficiency, low energy consumption, mild and simple operating conditions, and several other features, so it is widely used and developed rapidly. Separation membranes and corresponding membrane separation technologies have been widely used in food and beverage, medical and health, biotechnology, chemical metallurgy, environmental enginee...

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Problems solved by technology

Stelter et al. reported that the method for secondary growth and synthesis of SAPO-34 membranes (Chinese Patent Application No. 97193836.9) was adsorbed on the carrier after modifying the charge on the surface of the seed crystal, but for carriers with large pore sizes, this method cannot synthesize continuous dense Noble et al. reported in-situ hydrothermal synthesis of SAPO-34 film on porous supports (Chinese Patent Application No. 200580008446.8), Min Enze et al. reported in-situ synthesis of SAPO on the surface of flat porous ceramics -34 film (Chinese Patent Application No. 96106353.X), but because the in-situ synthesis method is only applicable to carriers with less porosity (such as ceramic sheet, ceramic tube), it cannot be applied to carriers with great porosity (such as stainless steel metal mesh, 100-300 mesh), and a large number of molecular sieves are formed in the pores, resulting in an increase in the thickness of the membrane. At the same time, the orientation of the synthesized membrane cannot be controlled by the in-situ method, and the molecular sieves accumulate irregularly on the surface and inside of the carrier, resulting in the passage of gas. The path increases, which greatly reduces the permeability of the membrane and cannot be used in industrial applications

For the preparation of aluminum phosphate molecular sieve membrane on the surface of ultra-large porosity carrier, there is no patent report yet

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