Preparation method of ZSM-5 molecular sieve with multi-level pore channel structure

Abstract

The invention relates to a preparation method of a ZSM-5 molecular sieve with a multi-level pore channel structure. The preparation method comprises the following steps of: performing activating treatment on natural layered clay by virtue of a high-temperature roasting mode; adding the activated natural layered clay into an acidic solution and performing acid treatment to obtain a mixture; adding water glass, a template agent and water sequentially into the mixture, so that the constitution of the mixture accords with the condition that the molar ratio of Na2O:Al2O3:SiO2:H2O is equal to (3-11):1:(20-100):(500-1500); adjusting the pH value of the mixture to 9-12 to obtain reactant gel; performing ageing treatment on the reactant gel; performing hydrothermal crystallization treatment on the aged reactant gel to obtain the ZSM-5 molecular sieve with the multi-level pore channel structure. By utilizing the method, the ZSM-5 molecular sieve with the multi-level pore channel structure is synthesized by taking the natural layered clay which is roasted at a high temperature as a unique aluminum source, taking the water glass as a supplemented silicon source and adopting the single template agent. The method has the advantages of simplicity and low cost.

Description

technical field [0001] The invention relates to a preparation method of a ZSM-5 molecular sieve, in particular to a preparation method of a ZSM-5 molecular sieve with a multi-level pore structure, and belongs to the technical field of preparation of molecular sieve materials. Background technique [0002] ZSM-5 molecular sieve is a high silica zeolite material with three-dimensional ordered microporous structure, because of its good thermal stability and hydrothermal stability, moderate acidity, high specific surface area and highly ordered micropores Channels are widely used in the modern petroleum processing industry. However, the pore size of ZSM-5 molecular sieve is small, it is difficult for macromolecules to enter the pores, and the diffusion resistance is large, and the macromolecules formed in the pores cannot diffuse out quickly, thus limiting its application in macromolecular catalytic reactions. [0003] Mesoporous materials can make up for the deficiency of micr...

AI Technical Summary

Problems solved by technology

However, the disadvantages of the above methods are: the synthesis of supercages and large-pore zeolite molecular sieves requires unique templates and can only be formed under strictly controlled crystallization conditions, and the synthesized nano-zeolite molecular sieves have poor hydrothermal stability, and Separation is difficult, and these shortcomings seriously affect the application of the above materials in industry

But above-mentioned two kinds of methods all have significant deficiencies: the method that introduces mesoporous template agent in the zeolite synthetic process has the shortcoming such as the suitable template agent is expensive, needs reasonable control to remove template agent; The composition has a great influence, which not only makes it difficult to control the pore size, but also causes a certain degree of damage to the crystal structure of the zeolite, affecting the hydrothermal stability and other properties of the zeolite.

[0007] In summary, the existing methods for preparing hierarchically porous materials have disadvantages such as cumbersome operation, high cost, and difficulty in controlling the pore structure and hydrothermal stability of the obtained material. In view of this, it is necessary to reduce the synthesis cost and simplify the operation procedure. It is of great practical significance to develop simple and efficient synthetic routes for hierarchically porous materials

Images