Method for synthesizing molecular sieve film using vacuum crystal method

Abstract

A method for synthesizing a type A molecular sieve membrane by evacuation and crystal coating method, the steps are: 1) introduce a layer of uniformly dispersed molecular sieve crystal seeds on the base membrane by using a vacuum pump to evacuate or compress with a compressor, and the evacuation or compression pressure is 0.0010 -0.0500Mpa, the dipping time is 30-300S, the concentration of the dipping solution is 1-20g / l, and the grain size is 0.20-10μm. 2) Synthesize A-type molecular sieve membrane by hydrothermal synthesis method and microwave synthesis method, and the solution composition of synthetic A-type molecular sieve membrane is: aNa2O:bAl2O3:5SiO2:cH2O, where a=(20-100), b=(0.5-5 ), c=(500-4000); hydrothermal or microwave synthesis, the temperature of hydrothermal synthesis is 323-373K, and the synthesis time is 2-60h; the temperature of microwave synthesis is 323-373K, and the synthesis time is 30-120min. The molecular sieve membrane synthesized by the method of the invention has good separation performance and high repeatability, and is suitable for industrial amplification.

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

And by adjusting Al 2 o 3 base film and SiO 2 The zata potential of the seed crystal or the method of introducing the 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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