A preparation method of graded mesoporous hydrated alumina microspheres with controllable crystal form

Abstract

The invention relates to a preparation method of graded mesoporous hydrated alumina microspheres with controllable crystal forms. The method comprises the following steps: quickly add a certain amount of formamide into the sodium aluminate solution, and stir evenly; then quickly add the solution into a hydrothermal kettle, heat and hydrolyze for a period of time, filter the white precipitate produced after cooling, and Washing with water and absolute ethanol in sequence to obtain a filter cake; drying the filter cake to obtain flower-like mesoporous hydrated alumina microspheres assembled from two-dimensional nanosheets in different crystal forms. The flower-shaped alumina hydrate microspheres of different crystal forms prepared by the present invention have good texture properties, and changing the hydrothermal time, hydrothermal temperature and formamide addition can make the pore structure parameters change within the following range: specific surface area 103.7~250.1m 2 / g, pore volume 0.20~0.35cm 3 / g, the average pore size is 4.3-5.4nm, and the pore size is concentrated at 3.3-5.2nm.

Description

technical field

[0001] The invention belongs to the technical field of alumina preparation, and in particular relates to a preparation method of graded mesoporous hydrated alumina microspheres with controllable crystal form. Background technique

[0002] Alumina hydrates of different crystal forms (pseudoboehmite, bayerite and gibbsite, etc.) and alumina are widely used in electronics, petrochemicals, refractories, ceramics, abrasives, paper, pharmaceuticals and aviation. , especially activated alumina with abundant Lewis acid sites and high surface area, is often used as a catalyst or catalyst support. In order to solve the problems of catalyst agglomeration and deactivation, friction damage and recycling loss in the heterogeneous catalytic reaction, the catalyst is usually required to have a certain particle size distribution, and the preparation of catalyst microspheres can well take into account the high surface area of ​​nanomaterials. Particle size of the material and...

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