Ambient pressure drying method for rapidly preparing SiO2 aerogel

An atmospheric pressure drying and airgel technology, which is applied in the field of nanomaterial preparation and nanometer mesoporous material preparation, can solve the problems of long atmospheric pressure drying process cycle, high production cost and poor repeatability, so as to improve the efficiency of solvent replacement and production Cost increase, effect of improving surface modification efficiency

Active Publication Date: 2013-03-06
卢斌
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The invention provides a fast preparation of SiO 2 Atmospheric pressure drying method of airgel to overcome traditional supercritical drying to prepare SiO 2 The airgel method has disa...

Method used

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  • Ambient pressure drying method for rapidly preparing SiO2 aerogel
  • Ambient pressure drying method for rapidly preparing SiO2 aerogel
  • Ambient pressure drying method for rapidly preparing SiO2 aerogel

Examples

Experimental program
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Effect test

Embodiment 1

[0037] Mix silicon alkoxide, absolute ethanol, deionized water, n-hexane and 0.1mol / L hydrochloric acid and then perform hydrolysis reaction to prepare sol. The hydrolysis time is 4 hours, and the hydrolysis temperature is 25°C. The molar ratio of silicon alkoxide and hydrochloric acid 1:9×10 -5 , the molar ratio of silicon alkoxide, absolute ethanol, deionized water and n-hexane is 1:4:4:1.5. In the prepared sol, add an appropriate amount of 0.1mol / L ammonia water, wherein the molar ratio of silicon alkoxide and ammonia water is 1:1.8×10 -4 , after stirring for 5 minutes, let it stand until it gels. The prepared gel was placed in absolute ethanol and aged at 50° C. for 10 h, which was equivalent to one replacement. A mixed solution of trimethylchlorosilane (TMCS) and n-hexane was used as a surface modifier to modify the aged gel, where the molar ratio of TMCS and n-hexane was TMCS:N-hexane=1:10, each time The modification time is 3h, and the modification is performed t...

Embodiment 2

[0040] In this embodiment, on the basis of Example 1, the amount of n-hexane added is changed.

[0041] Mix silicon alkoxide, absolute ethanol, deionized water, n-hexane and 0.1mol / L hydrochloric acid and then perform hydrolysis reaction to prepare sol. The hydrolysis time is 4 hours, and the hydrolysis temperature is 25°C. The molar ratio of silicon alkoxide and hydrochloric acid 1:9×10 -5 , the molar ratio of silicon alkoxide, absolute ethanol, deionized water and n-hexane is 1:4:4:1. In the prepared sol, add an appropriate amount of 0.1mol / L ammonia water, wherein the molar ratio of silicon alkoxide and ammonia water is 1:1.8×10 -4 , stir evenly and let stand until it gels. The prepared alcohol gel was placed in absolute ethanol, replaced twice with ethanol solvent for 2 hours each time, and aged at 50° C. for 10 hours. A mixed solution of trimethylchlorosilane (TMCS) and n-hexane was used as a surface modifier to modify the aged gel, where the molar ratio of TMCS an...

Embodiment 3

[0044] In this embodiment, on the basis of Example 1, the amount of n-hexane added is changed.

[0045] Mix silicon alkoxide, absolute ethanol, deionized water, n-hexane and 0.1mol / L hydrochloric acid and then perform hydrolysis reaction to prepare sol. The hydrolysis time is 4 hours, and the hydrolysis temperature is 25°C. The molar ratio of silicon alkoxide and hydrochloric acid 1:9×10 -5 , the molar ratio of silicon alkoxide, absolute ethanol, deionized water and n-hexane is 1:4:4:2. In the prepared sol, add an appropriate amount of 0.1mol / L ammonia water, wherein the molar ratio of silicon alkoxide and ammonia water is 1:1.8×10 -4 , stir evenly and let stand until it gels. The prepared gel was placed in absolute ethanol, replaced twice with ethanol solvent for 3 hours each time, and aged at 50° C. for 10 hours. A mixed solution of trimethylchlorosilane (TMCS) and n-hexane was used as a surface modifier to modify the aged gel, where the molar ratio of TMCS and n-hexa...

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Abstract

The invention discloses an ambient pressure drying method for rapidly preparing SiO2 aerogel. Part of an alcohol solvent is replaced with a solvent with low surface tension; silica-alkoxides, the non-replaced alcohol solvent, an acidic catalyst, a basic catalyst and the solvent with the low surface tension are prepared into sol according to a certain proportion, after alcogel containing the solvent with the low surface tension is formed, ageing and surface modification processes are carried out, and then, ambient pressure drying is directly carried out, so that the complex solvent exchanging step is omitted, and the SiO2 aerogel is prepared within 30h. By using the method, not only are the defects such as high equipment investment, low efficiency, high cost of the traditional supercritical drying process overcome, but also the problems of long period, high using cost for solvent exchanging and the like in the traditional ambient pressure drying process are solved, and the prepared SiO2 aerogel has the characteristics of low surface density, large specific area, large pore volume and the like.

Description

technical field [0001] The invention relates to a rapid preparation of SiO 2 The invention discloses an airgel drying method under normal pressure, which belongs to the technical field of nanometer material preparation. It further belongs to the technical field of preparation of nano mesoporous materials. Background technique [0002] SiO 2 As a new type of nano-light porous inorganic functional material, airgel has high specific surface area and porosity, good chemical stability, non-toxic to human body, excellent performance such as thermal insulation performance, catalytic activity and high adsorption, and has great advantages in energy saving. The fields of environmental protection and new energy all play a unique role. [0003] SiO 2 Commonly used drying processes for airgel include atmospheric pressure drying process and supercritical drying process. The supercritical drying process has high requirements on production equipment, and has problems such as low produc...

Claims

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Application Information

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IPC IPC(8): C01B33/158
Inventor 卢斌张丁日卢孟磊
Owner 卢斌
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