Method for synthesizing molecular sieve film using vacuum crystal method

Abstract

A process for synthesizing A-type molecular sieve membrane by the vacuumizing and coating crystals method includes such steps as introducing a layer of uniform crystal seeds to the surface of base membrane by vacuumizing or compressing method, and synthesizing A-type molecular sieve membrane by hydrothermal synthesis and microwave synthesis, where the used solution contains Na2O, Al2O3, SiO2 and H2O. The resulting molecular sieve membrane features high separation performance and high repeatability.

Description

technical field [0001] The invention relates to a method for synthesizing a molecular sieve membrane, in particular to a method for synthesizing a type A molecular sieve membrane by means of an evacuation and crystal coating method. Background technique [0002] Molecular sieve is a microporous inorganic crystal material formed with silicon-oxygen tetrahedron and aluminum-oxygen tetrahedron as the basic skeleton. Molecular sieves have the following advantages as inorganic membrane materials: 1) Molecular sieves have standardized and neat channels with a single pore size distribution; and the pore size of molecular sieves is similar to that of many important industrial raw materials. Molecules can be obtained by molecular sieving or type-selective diffusion. separate. 2) Molecular sieves have good chemical stability and thermal stability. 3) The diversity of molecular sieve structures leads to the diversity of its properties, such as different pore sizes and different hydro...

AI Technical Summary

Problems solved by technology

Dip-coating method is currently the most commonly used crystal-coating method, but in the process of dip-coating, the molecular sieve seed crystal sol-gel is difficult to be closely combined with the surface of the basement membrane and is easy to flow, so it is difficult to form uniform and continuous crystals. film

The wiping and coating crystal method is the easiest to operate, but it is actually difficult to introduce a uniform and continuous layer of seed crystals on the surface of the base film.

Although the spray coating method can introduce a uniform and continuous seed crystal film on the surface of the flat base film, it is difficult to form a uniform and continuous seed crystal film on the surface of the tubular base film, so it is not suitable for industrial scale-up and has no industrial application value.

Although the laser pulse deposition coating method can introduce a uniform and continuous seed crystal film on the surface of the base film, it requires expensive lasers, so it has no industrial application value

However, the method of adjusting the zata potential of the Al2O3 base film and the SiO2 seed crystal or introducing a seed crystal film on the surface of the base film through electrostatic interaction is complicated to operate, difficult to control, and not suitable for industrial scale-up.

These reasons restrict the synthesis of molecular sieve membranes to a certain extent, thus also restricting the industrial application of molecular sieve membranes

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