Green energy-saving Fe-ZSM-5 molecular sieve synthesis method

Abstract

The invention discloses a green energy-saving Fe-ZSM-5 molecular sieve synthesis method which includes the steps: (1) uniformly mixing reaction raw materials including sodium silicate, fumed silica, tetrapropylammonium bromide, ammonium chloride, iron salt and hydrogen peroxide in a mortar, and manually grinding the reaction raw materials for 15-20 minutes; (2) transferring mixture obtained in thestep (1) into a high pressure reactor with a polytetrafluoroethylene liner, performing low-temperature pretreatment at the temperature of 50-80 DEG C for 1-18 hours and then performing high-temperature crystallization at the temperature of 180 DEG C for 24-48 hours; (3) cooling the mixture to room temperature after crystallization reaction, sequentially performing centrifugal washing by the aid of deionized water and absolute ethyl alcohol until supernatant is clarified, and drying the mixture at the temperature 110 DEG C for 150 minutes to obtain molecular sieve raw powder; (4) roasting themolecular sieve raw powder obtained in the step (3) at the temperature of 550 DEG C for 4 hours to obtain Fe-ZSM-5 molecular sieve powder.

Description

technical field [0001] The invention relates to the preparation technology of iron-based catalyst, in particular to the synthesis technology of Fe-ZSM-5 molecular sieve. Background technique [0002] Zeolite molecular sieves have been widely used in the fields of adsorption separation, catalysis and ion exchange due to their unique pore structure, strong acidity and high hydrothermal stability. [0003] ZSM-5 zeolite molecular sieve is an inorganic crystalline material developed by Mobil Corporation. It is widely used as an FCC catalyst promoter because of its regular pore structure, strong acidity, good hydrothermal stability and excellent selectivity. , methanol to olefins catalysts and other fields. Modification by introducing Fe into the ZSM-5 molecular sieve framework can effectively adjust its acidity and can be used as NH 3 Selective Catalytic Reduction of NO x Catalysts for reaction, synthesis gas to olefins reaction and phenol hydroxylation reaction. [0004] At...

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Problems solved by technology

[0004] At present, the most common methods for preparing Fe-ZSM-5 molecular sieves are hydrothermal method and post-treatment method. Although the iron element is successfully introduced into the molecular sieve framework, there are also many defects, such as using a large amount of water as a solvent in the hydrothermal system. , not only produce a large amount of waste water to pollute the environment, but also generate high self-generated pressure during the synthesis process to bring safety problems; the post-treatment method is cumbersome to operate, and the hydroxyl groups on the surface of the molecular sieve are greatly reduced after high-temperature roasting in the preparation of mesoporous molecular sieves, resulting in the introduction of iron The content is relatively small, and most of the introduced iron species are concentrated on the surface of the substrate, and the synthesis efficiency is low

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