Preparation method of orientation LTL type molecular sieving membrane for gas separation

Abstract

The invention relates to a preparation method of an orientation LTL type molecular sieving membrane for gas separation. The preparation method comprises the following steps: (1) mixing an alkali source, an aluminum source, a silicon source and deionized water to obtain gel and performing hydrothermal crystallization for preparing a seed crystal; (2) performing acidic treatment on the seed crystal prepared in the step (1) so as to remove aluminum from the grain surface, and then preparing a suspension in sec-butyl alcohol, and stirring for modifying; (3) dropwise adding the LTL type molecular sieving suspension acquired by modifying in the step (2) into an LB liquid tank for forming a membrane, and then transferring the acquired membrane onto the surface of a carrier; (4) mixing an alkali source, an aluminum source, a silicon source and deionized water to obtain a secondary growth synthetic solution; (5) contacting the product from the step (3) with the secondary growth synthetic solution from the step (4), performing hydrothermal crystallization and acquiring the LTL type molecular sieving membrane on the carrier. According to by the invention, the simple, controllable, efficient and repeatable LB method is adopted for preparing the orientation LTL type molecular sieve seed crystal layer and the high c-axis orientation LTL type molecular sieving membrane is prepared through secondary growth; the operation is simple, the degree of orientation is easily controlled, and the repeatability is high.

Description

Technical field: [0001] The invention belongs to the technical field of inorganic membrane preparation, and in particular relates to a preparation method of an oriented LTL molecular sieve membrane for gas separation. Background technique: [0002] Separation is an important unit operation in the process industry, accounting for 40% to 60% of the total energy consumption. Gas membrane separation has significant advantages such as low operating energy consumption and high separation efficiency, and plays an important role in the process industry intensification. The separation of hydrogen and carbon dioxide is a key step in clean energy and carbon dioxide capture. Using selective membrane materials to achieve the separation at the molecular level is one of the key technical issues that the industry has been committed to solving for a long time. [0003] Zeolite molecular sieve is an ideal material for gas adsorption and separation due to its regular pore structure, adjustabl...

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Problems solved by technology

However, the molecular sieve membrane contained in this patent is a molecular sieve membrane with a silicoaluminophosphate structure, and the membrane does not have orientation

[0006] Due to the narrow secondary growth crystallization interval, easy crystal transition and difficulty in controlling the degree of orientation during the preparation of oriented LTL molecular sieve membranes, there have been no reports in the literature and patents on the preparation of c-axis oriented LTL molecular sieve membranes by the LB method. The literature and patents of using c-axis oriented ultra-large microporous LTL molecular sieve membrane for gas separation have not been reported yet.

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