Preparation method of silicon dioxide aerogel and prepared silicon dioxide aerogel

A silica and aerogel technology, applied in silica, silica, chemical instruments and methods, etc., can solve the problems of cumbersome operations, multiple times, and long preparation cycles, so as to reduce preparation time and avoid solid waste. , to avoid the effect of various pollution

Inactive Publication Date: 2019-04-19
安徽科昂纳米科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The problem to be solved by the present invention is that the existing normal pressure drying method requires multiple solvent replacements, and the preparation period is long and the operation is cumbersome.

Method used

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  • Preparation method of silicon dioxide aerogel and prepared silicon dioxide aerogel
  • Preparation method of silicon dioxide aerogel and prepared silicon dioxide aerogel
  • Preparation method of silicon dioxide aerogel and prepared silicon dioxide aerogel

Examples

Experimental program
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Effect test

Embodiment 1

[0037] A preparation method of silica airgel, comprising the following steps:

[0038] (1) Mix 40g sodium hydroxide, 500g water, and 500g ethanol into a uniform solution, add 50g of hydrophobic fumed silica, and dissolve to become a clarified modified sodium silicate liquid;

[0039] (2) adding 85g mass fraction of 50% sulfuric acid solution into the modified sodium silicate liquid and stirring, so that the pH value of the solution is between 4-6, because this reaction is an exothermic reaction in order to control the reaction speed, the acid solution The joining speed should not be too fast;

[0040] (3) After stirring and cooling to room temperature, the solution was filtered to remove the precipitated sodium sulfate crystals to obtain a clear solution, which was left to stand at 60° C. for 1 hour to obtain a modified silica gel;

[0041] (4) Add 1000g of n-heptane solution to the gel and heat it to 90°C. After 3 hours, the solution is layered. The upper layer is silica gel...

Embodiment 2

[0046] A preparation method of silica airgel, comprising the following steps:

[0047] (1) Mix 20g sodium hydroxide, 1000g water, and 500g ethanol into a uniform solution, add 50g of hydrophobic fumed silica, and dissolve to become a clarified modified sodium silicate liquid;

[0048] (2) adding 150g mass fraction of 40% nitric acid solution into the modified sodium silicate liquid and stirring, because this reaction is an exothermic reaction in order to control the reaction speed, the acid solution addition speed should not be too fast;

[0049] (3) After stirring and cooling to room temperature, the solution was filtered to remove the precipitated sodium nitrate crystals to obtain a clear solution, which was left to stand at 60°C for 40 minutes to obtain a modified silica gel;

[0050] (4) Add 600 g of n-hexane solution to the gel and heat it to 70°C. After 3 hours, the solution is layered. The upper layer is silica gel and n-pentane solution, and the lower layer is ethanol ...

Embodiment 3

[0053] A preparation method of silica airgel, comprising the following steps:

[0054] (1) Mix 100g of sodium hydroxide, 50g of water, and 500g of ethanol into a uniform solution, add 50g of hydrophobic fumed silica, and dissolve to become a clarified modified sodium silicate liquid;

[0055] (2) adding 100g mass fraction of 20% hydrochloric acid solution into the modified sodium silicate liquid and stirring, because this reaction is an exothermic reaction in order to control the reaction speed, the acid solution addition speed should not be too fast;

[0056] (3) After stirring and cooling to room temperature, the solution was filtered to remove the precipitated sodium chloride crystals to obtain a clear solution, which was left to stand at 60° C. for 1 hour to obtain a modified silica gel;

[0057] (4) Add 600g of hexamethyldisiloxane solution to the gel and heat it to 70°C. After 3 hours, the solution is layered. The upper layer is silica gel and hexamethyldisiloxane soluti...

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Abstract

The invention discloses a preparation method of silicon dioxide aerogel. The problems need to be solved that for an existing normal-pressure drying method, multi-time solvent replacement is needed, the preparation period is long, and operation is complex. According to the method, silicon dioxide and sodium hydroxide react to generate modified sodium silicate, and ethyl alcohol/water is used as a solvent; inorganic acid is added for neutralizing a modified sodium silicate solution, then a modified silica solution is generated, an inorganic salt by-product is removed, and modified silica gel isgenerated through the modified silica solution at certain temperature and pressure; a nonpolar solvent is used for conducting solvent exchange on the modified silica gel and drying the modified silicagel to obtain a hydrophobic aerogel material. The preparation method of the silicon dioxide aerogel has the advantages that the time of preparing the aerogel is short, the cost is low, and wastewater, waste gas and solid waste are not generated.

Description

technical field [0001] The invention relates to the technical field of nano light materials, in particular to a method for preparing silica airgel and the prepared silica airgel. Background technique [0002] Airgel material is a lightweight porous product obtained by replacing the internal solvent with air while keeping its skeleton unchanged, and its porosity can reach more than 95%. The lightest solid substance known. According to different skeleton materials, aerogels can also be divided into silica aerogels, alumina aerogels, titania aerogels, carbon aerogels, etc., due to their unique microstructure and surface groups , airgel has many excellent physical and chemical properties, such as low density, low thermal conductivity, low sound velocity transmission rate, high adsorption rate, etc. [0003] The current preparation methods of airgel usually include supercritical drying and normal pressure drying methods. Supercritical drying is to heat and pressurize the solut...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/16
CPCC01B33/166C01P2006/17
Inventor 张尚权
Owner 安徽科昂纳米科技有限公司
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