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Preparation method of silica aerogel under atmospheric pressure

A silicon dioxide and aerogel technology, applied in chemical instruments and methods, inorganic chemistry, silicon compounds, etc., can solve the problems of gel cracking, complex preparation process, limited extensiveness, etc., to reduce surface tension and simplify the process. The effect of reducing and reducing the risk factor

Inactive Publication Date: 2018-08-21
ZHEJIANG UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are still problems such as gel cracking and complicated preparation processes, which limit the wide range of applications.

Method used

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  • Preparation method of silica aerogel under atmospheric pressure
  • Preparation method of silica aerogel under atmospheric pressure
  • Preparation method of silica aerogel under atmospheric pressure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] Example 1 Preparation of silica airgel

[0045] The preparation method of the silica airgel of embodiment 1 of the present invention comprises the following steps:

[0046] (1) Add tetraethyl orthosilicate, absolute ethanol and deionized water into the container, and mix and stir for 10 min according to molar ratio, tetraethyl orthosilicate: absolute ethanol: deionized water at 1:12:6; Add 1 mol / L hydrochloric acid, adjust the pH to 2, stir and hydrolyze for 1.5 hours to obtain silica sol;

[0047](2) Add 0.446 mol / L ammonia water to the above silica sol, slowly add drop by drop and stir while adding, adjust the pH to 7, and wait for it to gel at room temperature until the container is tilted more than 45° , until the liquid level in the container does not tilt;

[0048] (3) Put the gel in a plastic or glass container, add tetraethyl orthosilicate in a volume ratio of 1:4 to the mother liquor for aging, seal it and leave it at room temperature for aging for 24 hours; ...

Embodiment 2

[0062] Example 2 Preparation of silica airgel

[0063] The preparation method of the silica airgel of the embodiment 2 of the present invention comprises the following steps:

[0064] (1) Add methyl orthosilicate, absolute ethanol and deionized water into the container, and mix and stir for 20 min in a molar ratio of methyl orthosilicate: absolute ethanol: deionized water at 1:5:1; Add 4 mol / L hydrochloric acid, adjust the pH to 2.5, stir and hydrolyze for 2 hours to obtain silica sol;

[0065] (2) Add 1 mol / L ammonia water to the above-mentioned silica sol, add drop by drop slowly and stir while adding, adjust the pH to 7.5, and wait for it to gel at room temperature until the container is tilted more than 45° , until the liquid level in the container does not tilt;

[0066] (3) Put the gel in a plastic or glass container, add tetraethyl orthosilicate in a volume ratio of 1:4 to the mother liquor for aging, seal it and leave it at room temperature for aging for 24 hours;

...

Embodiment 3

[0071] Example 3 Preparation of silica airgel

[0072] The preparation method of the silica airgel of embodiment 3 of the present invention comprises the following steps:

[0073] (1) Add methyltrimethoxysilane, absolute ethanol and deionized water into the container, in molar ratio, methyltrimethoxysilane: absolute ethanol: deionized water is 1:7:3, mix and stir for 15 min ; Then add 1 mol / L hydrochloric acid to adjust the pH to 3, stir and hydrolyze for 3 hours to obtain silica sol;

[0074] (2) Add 0.446mol / L ammonia water to the above silica sol, add drop by drop slowly and stir while adding, adjust the pH to 8, and wait for it to gel at room temperature until the container is tilted over 45° , until the liquid level in the container does not tilt;

[0075] (3) Put the gel in a plastic or glass container, add tetraethyl orthosilicate in a volume ratio of 1:4 to the mother liquor for aging, seal it and leave it at room temperature for aging for 24 hours;

[0076] (4) Pla...

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Abstract

The invention discloses a method for preparing super-hydrophobic silica aerogel by atmospheric pressure drying. The method comprises the following steps: 1) preparing sol; 2) gelatinizing the sol; 3)aging gel; 4) exchanging a gel solvent; 5) carrying out surface hydrophobic modification; and 6) carrying out drying under atmospheric pressure. According to the preparation method of the silica aerogel, provided by the invention, tetraethoxysilane is used as a silicon source, ethanol is used as a solvent, acid and alkali are used as catalysts, and trimethylchlorosilane is used as a surface modifier, so that super-hydrophobic silica aerogel is prepared by atmospheric pressure drying. The prepared SiO2 aerogel with a super-hydrophobic three-dimensional network structure is tested to have a highspecific surface area, low density and good hydrophobicity at a room temperature. Therefore, the silica aerogel prepared through the method provided by the invention has excellent adsorption performance and has a good application prospect in the field of energy conservation. The preparation method of the silica aerogel under atmospheric pressure, provided by the invention, is simple in procedureand low in equipment requirements, can also shorten the process flow and reduce the cost, and is easy to industrialize.

Description

technical field [0001] The invention belongs to the technical field of silica airgel preparation, and in particular relates to a normal-pressure preparation method of silica airgel. Background technique [0002] Silica airgel is a nanoporous material with a three-dimensional network structure, known as "blue smoke", and more than 96% of its composition is gas, which is currently the lightest solid in the world. This special structure makes it have high porosity (85-95%, up to 99.8%), small pore size (1-100nm), high specific surface area (1000m 2 / g), low density (0.03-0.2g / cm 3 ), small refractive index (1.01-11), low sound velocity (100m / s), ultra-low thermal conductivity 0.015W / (m·K) and other properties. Because of its unique properties, it has broad application prospects in the fields of aerospace, construction, medicine and catalysts. [0003] Silica airgel is generally prepared by supercritical drying, which has good molding effect and can maintain a complete three-...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/158C01B33/157
CPCC01B33/1585C01B33/157C01P2002/82C01P2004/03C01P2004/04C01P2006/10C01P2006/12C01P2006/16C01P2006/17C01P2006/32C01P2006/90
Inventor 王建国包志康宋鑫
Owner ZHEJIANG UNIV OF TECH
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