Method for synthesizing micro-mesoporous composite molecular sieve based on multiple molecular sieves

Abstract

The invention provides a method for synthesizing a micro-mesoporous composite molecular sieve based on multiple molecular sieves. The method comprises the following steps: synthesizing a mesoporous molecular sieve by using microporous molecular sieves, and regulating the pH value to control the reaction depth and regulate the pH value of the crystallization mother liquor by using amorphous silica-alumina among microporous molecular sieve unit cell particles and silica-alumina at the unit cell edge part as silica-alumina sources, so that the microporous structure is reserved, and the micro-mesoporous composite molecular sieve containing a large number of mesoporous structures is formed. According to the invention, the respective limitations of the microporous molecular sieve and the mesoporous molecular sieve are overcome, the molecular sieves with two pore diameters can be effectively and organically combined, so that the advantages of the two molecular sieves can be complemented, macromolecules have more pore channels in the adsorption process and can enter the molecular sieves, meanwhile, a large number of micropores provide adsorption active sites, and can be used for absorbing pollutants in blast furnace gas in the metallurgical or petrochemical industry, and thus the tail end flue gas treatment cost is reduced.

Description

technical field [0001] The invention relates to a micro-mesoporous composite molecular sieve, in particular to a method for synthesizing a micro-mesoporous composite molecular sieve based on various molecular sieves. Background technique [0002] As an effective porous material, microporous molecular sieves are widely used in petroleum smelting, fine chemical industry and adsorption separation. The representative material is zeolite molecular sieve. The outstanding feature of zeolite molecular sieve is that it can adjust the acidity and provide different The channel and internal hole travel shape-selective effect. This row selection effect can promote H 2 For the adsorption of S, according to the pseudo-first-order kinetics and pseudo-second-order kinetics models, there are two reaction paths for molecular sieves to adsorb pollutants in blast furnace gas, physical adsorption and chemical adsorption, and in these two reaction paths, physical adsorption Mainly rely on mesopo...

AI Technical Summary

Problems solved by technology

People hope that mesoporous molecular sieves can be applied to the reaction of macromolecules, but there is a big difference between mesoporous molecular sieves and microporous molecular sieves in the molecular sieve skeleton. Compared with microporous molecular sieves, mesoporous molecular sieves do not have repeated single cells. The structural unit, whose internal structural unit is similar to an amorphous oxide, does not contain a crystalline structure region, and only has a local ordered structure. Therefore, the aluminum-containing mesoporous molecular sieve is similar to the amorphous aluminosilicate, and has weak and Medium-strength acidity, coupled with poor hydrothermal stability, and mesoporous molecular sieves have shape-selective catalytic oxidation absorption for macromolecules, but for small molecules, they do not have good absorption. Therefore, in large To some extent, it limits its industrial application in the field of adsorbents