Method for in-situ synthesis of nano Zn/Al-ZSM-5 molecular sieve with steam-assisted dry glue conversion method

Abstract

The invention discloses a method for in-situ synthesis of a nano Zn / Al-ZSM-5 molecular sieve with a steam-assisted dry glue conversion method. The invention belongs to the field of preparation of zeolite molecular sieve catalysts and aims to solve the problems that a conventional method for synthesizing a nano Zn / Al-ZSM-5 molecular sieve is long in crystallization time, large in energy consumption, large in molecular sieve crystal granule size and large in product waste liquid amount. The method comprises the following steps: I, weighing raw materials; II, mixing aluminum isopropoxide, a tetrapropylammonium hydroxide solution, tetraethoxysilane, zinc nitrate hexahydrate and deionized water, and carrying out vacuum drying so as to obtain a dry glue; and III, grinding the dry glue, putting the dry glue into a vessel at the upper part of a crystallization kettle, supporting the vessel by using a bracket, feeding deionized water into the bottom of the crystallization kettle, and carrying out crystallization at 160-190 DEG C, so as to obtain the nano Zn / Al-ZSM-5 molecular sieve. By adopting the method disclosed by the invention, the problem that a product is hard to separate from a mother liquid in the hydrothermal crystallization process is effectively avoided, the yield of the molecular sieve can be greatly increased, and a waste liquid with organic matters and alkalis are not generated after crystallization.

Description

technical field [0001] The invention belongs to the field of preparation of zeolite molecular sieve catalysts, and in particular relates to a preparation method of nanometer Zn / Al-ZSM-5 zeolite molecular sieve with partial isomorphic replacement of zinc. Background technique [0002] Molecular sieve catalysts have excellent thermal stability, hydrothermal stability and outstanding shape selectivity, and are widely used in the fields of acid catalysis, selective oxidation and adsorption separation. At present, there are two major research directions around the synthesis of molecular sieves: (1) according to the functional requirements, directional design and construction of molecular sieve frameworks with special pore structures, and synthesis of microporous crystalline materials with new structures; (2) for existing molecular sieve materials , develop new preparation methods, and regulate the properties of molecular sieves such as diffusion and acidity. The traditional hydr...

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Problems solved by technology

[0004] The present invention aims to solve the problems of long crystallization time, high energy consumption, large molecular sieve grain size and large amount of waste liquid existing in the existing method for synthesizing nanometer Zn / Al-ZSM-5 molecular sieves, and provides a steam-assisted drying method. A New Green Synthesis Method for In Situ Synthesis of Nano Zn / Al-ZSM-5 Molecular Sieves by Gel Conversion Method

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