Process for preparing zeolite material with multi-class pore canal by zeolitizing diatomite

Abstract

A process for preparing zeolite with multi-class pore canal structure by zeolitizing diatomite features use of laminating technique and gas-solid crystal conversion technique. For the laminating technique, an electrostatic attraction is used to assemble the nano zeolite onto diatomite. For the gas-solid crystal conversion technique, the amorphous SiO2 is converted to zeolite without damage to the form and structure of diatomite. Its advantages are simple operation, high speed, rich macropores, environmentally friendly process and wide application range.

Description

technical field [0001] The invention is a method for preparing a novel zeolite material with a multi-level pore structure by zeolizing diatomite. Background technique [0002] As a porous inorganic material, zeolite has abundant micropores, molecular screening properties and good thermal and hydrothermal stability, and is widely used in catalytic and adsorption separation processes. Generally, the directly synthesized zeolite is a relatively loose crystal powder. In practical applications, various binders (such as clay or silicate, etc.) need to be added to shape, but the result is that the effective surface area of ​​the material is often significantly reduced, and the diffusion process is introduced. limit. Likewise, more recent binderless zeolites have been shown to have larger diffusion problems. A better way to increase the effective surface area of ​​zeolite and reduce diffusion is to prepare zeolite material with multi-level pore structure. The preparation of such ...

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Problems solved by technology

[0003] At present, there are mainly the following preparation methods: Holland et al. poured the precursor of the synthetic zeolite into the voids of closely packed polystyrene beads, and synthesized a three-dimensional micropore / macropore by using the method of in-situ pseudosolid phase crystallization of the zeolite. The monolithic silicalite-1 zeolite with structure (B.T.Holland, L.Abrams and A.Stein, J.Am.Chem.Soc., 1999, 121, 4308); Valtchev et al prepared silicalite by seed-film growth method -1 zeolite carbon fiber coating fiber, and obtain silicalite-1 zeolite hollow fiber by roasting (V.Valtchev, B.J.Schoeman, J.Hedlund, S.Mintova and J.Sterte, Zeolites, 1996,17,408); Wang Xingdong et al. Using polystyrene spheres as a template, a layer of zeolite membrane is covered on its surface by nano-zeolite layer-by-layer assembly method, and zeolite hollow spheres are obtained by roasting (X.D.Wang, W.L.Yang, Y.Tang, Y.J.Wang, S.K.Fu and Z .Gao, Chem.Commun., 2000(21), 2161) etc., but these methods all need to adopt a large amount of templates to maintain the required macroporous structure, and the removal of the templates can not be underestimated to the environment

More importantly, after removing the template agent, the strength of this kind of material is very poor, which is difficult for practical application

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