CN116986600A - Method for preparing silicon dioxide aerogel based on water glass - Google Patents

Method for preparing silicon dioxide aerogel based on water glass Download PDF

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Publication number
CN116986600A
CN116986600A CN202310894157.2A CN202310894157A CN116986600A CN 116986600 A CN116986600 A CN 116986600A CN 202310894157 A CN202310894157 A CN 202310894157A CN 116986600 A CN116986600 A CN 116986600A
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silica
wet gel
water glass
silica aerogel
water
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傅建华
程四清
江边
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Silicon Gem Wuhan High Tech Equipment Co ltd
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Silicon Gem Wuhan High Tech Equipment Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C01B33/157—After-treatment of gels
    • C01B33/158—Purification; Drying; Dehydrating
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C01B33/141—Preparation of hydrosols or aqueous dispersions
    • C01B33/142—Preparation of hydrosols or aqueous dispersions by acidic treatment of silicates
    • C01B33/143—Preparation of hydrosols or aqueous dispersions by acidic treatment of silicates of aqueous solutions of silicates
    • C01B33/1435—Preparation of hydrosols or aqueous dispersions by acidic treatment of silicates of aqueous solutions of silicates using ion exchangers
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/113—Silicon oxides; Hydrates thereof
    • C01B33/12—Silica; Hydrates thereof, e.g. lepidoic silicic acid
    • C01B33/14—Colloidal silica, e.g. dispersions, gels, sols
    • C01B33/146—After-treatment of sols
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/12—Surface area
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/14—Pore volume
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/16—Pore diameter

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  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Silicon Compounds (AREA)

Abstract

The application discloses a method for preparing silica aerogel based on water glass, and belongs to the technical field of silica aerogel preparation. According to the method for preparing the silicon dioxide aerogel based on the water glass, the water glass is used as a silicon source to prepare the silicon dioxide wet gel, and then the silicon dioxide wet gel is soaked in an isopropanol/trimethylchlorosilane/n-hexane solvent system, so that solvent exchange and surface modification can be simultaneously realized, and the peripheral solvent of the silicon dioxide wet gel is subjected to phase separation, so that the solvent is easy to recycle.

Description

Method for preparing silicon dioxide aerogel based on water glass
Technical Field
The application belongs to the technical field of preparation of silica aerogel, and particularly relates to a method for preparing silica aerogel based on water glass.
Background
As a typical aerogel, the silica aerogel is a three-dimensional network skeleton structure formed by highly cross-linking and polymerizing Si-O-Si chains, has a plurality of excellent performances such as high porosity, low density, low refractive index, low dielectric constant, high specific surface area, low heat conductivity and the like, and has wide application in the fields of heat insulation and preservation, adsorption catalysis, building energy conservation, medical foods, electronic communication and the like, so the silica aerogel attracts attention of people, and is one of the important research fields of material science.
At present, main factors restricting the large-scale application of the silica aerogel comprise high preparation cost, long period, complex process, insufficient toughness and low strength, so that mass production is difficult to realize. The preparation method of the silica aerogel at home and abroad generally adopts a sol-gel method, and the method mainly comprises two processes: (1) wet gel formation; (2) drying the wet gel to form an aerogel. Wherein the choice of drying process is critical to the successful preparation of the aerogel. The traditional drying process for preparing the silicon dioxide aerogel usually adopts a supercritical drying technology, high-pressure kettle equipment is needed, the preparation cost is high, the energy consumption is high, and the industrial mass production is not facilitated. The normal pressure drying technology is the development trend of the industrialization of the silica aerogel. However, the conventional organosilicon sources such as orthosilicate and silane used for preparing the silica aerogel by normal-pressure drying have high raw material cost and toxicity, which seriously hinders the application and popularization of the silica aerogel. Thus, the atmospheric preparation of silica aerogel using inexpensive sources of silicon such as water glass is a potential choice for the commercial development of silica aerogel.
In 1931, kistler successfully prepared silica aerogel using water glass as a raw material for the first time by using a sol-gel process and a supercritical drying technology. Then, the process of preparing the silica wet gel by using the sol-gel method by taking water glass as a silicon source is researched more, wherein the water glass is mainly mixed with an acid catalyst, or the water glass is subjected to ion exchange to form active silicic acid, then an alkaline catalyst is used for forming silica sol, the silica sol is subjected to condensation polymerization to form silica gel, and finally the prepared silica gel is aged to obtain the silica wet gel with complete structure. Therefore, the key point in the preparation of silica aerogel is how to dry the silica wet gel obtained by sol-gel process using water glass as silicon source under normal pressure, which is related to capillary pressure generated by dispersed phase solvent during drying and strength of silica wet gel skeleton. The process for drying the silica wet gel at normal pressure mainly comprises the steps of exchanging water in the silica wet gel with an organic solvent with relatively small surface tension through solvent exchange or surface modification of the silica wet gel, reducing capillary pressure in the drying process, and avoiding pore collapse in the silica wet gel drying process as much as possible, so that the pore volume and specific surface area of the silica aerogel are reduced; on the other hand, the surface of the silica wet gel can be modified to passivate the surface active hydroxyl groups, so that the collapse of the pores of the silica wet gel caused by condensation polymerization of the surface active hydroxyl groups during drying is avoided. Regardless, the silica wet gel atmospheric drying process always requires a solvent exchange process. However, since the solvent exchange process relies on a concentration gradient between solvents, a long diffusion time is required; in addition, the solvent recovery adopts high-temperature distillation, which requires a large amount of investment and high energy consumption. Therefore, the normal pressure drying technology for preparing the silica aerogel should take the solvent exchange as reduced as possible as the center of gravity of research and development.
Disclosure of Invention
Aiming at the problems that the prior normal pressure drying technology in the preparation process of the silicon dioxide aerogel needs solvent exchange, and has long time consumption, high solvent recovery cost and high energy consumption, so that large-scale production is difficult to realize, the application provides a method for preparing the silicon dioxide aerogel based on water glass.
In a first aspect, the present application provides a method for preparing silica aerogel based on water glass, comprising the steps of:
taking water glass as a silicon source, and performing ion exchange with cation exchange resin to obtain active silica sol;
ammonia water solution is used as a catalyst, the pH value of the active silica sol is regulated, and the solution is continuously stirred, sealed and kept stand to prepare crude silica aerogel;
soaking the aged crude silica aerogel in a mixed solution, and carrying out phase separation to obtain siliconized silica wet gel;
and drying the siliconized silica wet gel at room temperature to obtain the silica aerogel.
Further, the modulus of the water glass is 3.0-3.5, and the concentration is 8-30wt%.
Further, the pH value of the active silica sol is 2.0-3.0.
Further, the concentration of the ammonia water solution is 0.5-1.0M, and the pH value of the active silica sol regulated by the ammonia water solution is 4.0.
Further, the continuous stirring time is 20-40 s, the sealing and standing time is 8-12 h, and the aging time is 20-28 h.
Further, the crude silica aerogel is aged to form silica wet gel, the mixed solution is a mixed solution of isopropanol, trimethylchlorosilane and n-hexane, the mole ratio of the trimethylchlorosilane, the isopropanol and water in pores of the silica wet gel is 1-2:1-2:4-5, and the volume ratio of the n-hexane to the trimethylchlorosilane is 8-10: 1.
compared with the prior art, the technical scheme provided by the embodiment of the application has at least the following advantages:
1. the application discloses a method for preparing silicon dioxide aerogel based on water glass, which is a technology capable of simultaneously carrying out solvent exchange and surface modification in a drying process and is a technology capable of simultaneously realizing phase separation and normal-pressure drying. The technology takes cheap sodium silicate as a silicon source, prepares active silica sol by exchanging sodium ions with cation exchange resin, prepares silica gel by taking ammonia water as a catalyst, and prepares the silica wet gel by normal temperature aging in deionized water.
The normal pressure drying technology of the silica wet gel is to utilize an isopropanol/trimethylchlorosilane/n-hexane solvent system, wherein trimethylchlorosilane can react with water to generate water-insoluble hexamethyldisiloxane which is dissolved in n-hexane and water-soluble hydrochloric acid, and a siliconizing agent which can react with hydroxyl groups on the pore surfaces of the silica wet gel, so that a two-phase system of n-hexane/isopropanol and isopropanol/water/hydrochloric acid is realized, the silica wet gel is positioned below an n-hexane/isopropanol phase and above the isopropanol/water/hydrochloric acid phase, and the two-phase separation is realized through phase separation, so that the n-hexane which is easy to dry is arranged in the pores of the silica wet gel.
2. According to the method disclosed by the application, the low-cost water glass is used for replacing the organic silicate commonly used in the normal-pressure drying process to prepare the silicon dioxide aerogel, so that the production cost and the toxicity in the production process are obviously reduced, the large-scale production is easy to realize, and the method has good social and economic benefits.
3. According to the method disclosed by the application, the solvent system isopropanol/trimethylchlorosilane/n-hexane is utilized to simultaneously perform solvent exchange and wet gel inner surface modification on the silica wet gel, so that phase separation is realized at the periphery of the silica wet gel, the replacement of a solvent is not needed, and the solvent exchange time is saved; the surface energy of the wet gel is reduced after the inner surface of the wet gel is modified, the surface water content is low, and the wet gel is easy to dry.
4. Compared with the silica aerogel prepared by a wallboard sol exchange drying system, the method disclosed by the application has good blocking property and certain toughness, which indicates that the solvent drying system generates smaller capillary pressure in the silica wet gel and the strength of the gel skeleton is enhanced after the surface modification.
5. Compared with the silica aerogel prepared by the traditional solvent exchange method, the silica aerogel prepared by the application has the characteristics of large specific surface area, smaller average pore diameter and larger pore volume (as shown in table 1), and the silica nano particles in the silica aerogel prepared by the application are uniformly distributed and have rich gaps.
6. The method (5) disclosed by the application has the advantages of simple and convenient operation, cheap raw materials and short solvent exchange time in the process of preparing the silica aerogel, can directly recover the solvent by utilizing phase separation, does not need high energy consumption, and provides a new way for large-scale production of the silica aerogel.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, serve to explain the principles of the application.
In order to more clearly illustrate the embodiments of the application or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to a person skilled in the art that other drawings can be obtained from these drawings without inventive effort.
FIG. 1 is a schematic structural and SEM image of silica aerogel prepared using different solvent volumes.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
Unless otherwise specifically indicated, the various raw materials, reagents, instruments, equipment and the like used in the present application are commercially available or may be prepared by existing methods.
In a first aspect, the present application provides a method for preparing silica aerogel based on water glass, comprising the steps of:
(1) The water glass is used as a silicon source, the diluted water glass is subjected to ion exchange through cation exchange resin, and cation impurities in the solution are removed to prepare the active silica sol, wherein the pH is controlled to be 2-3.
(2) And (3) using 0.5-1.0M ammonia water solution as a catalyst, continuously stirring for 20-40 seconds when the pH value of the prepared active silica sol is regulated to be 4.0, transferring the active silica sol into a polypropylene small bottle, sealing, and standing for 8-12 hours to form the silica hydrogel. In order to strengthen the gel structure, the obtained silica hydrogel is aged in deionized water for 20-28 hours to obtain the silica wet gel.
(3) The aged silica wet gel is soaked in the mixed solution of isopropanol/trimethylchlorosilane/n-hexane, and after a period of time, the peripheral solvent of the silica wet gel is subjected to phase separation, and the siliconized silica wet gel is positioned at the bottom of the upper n-hexane oil phase.
(4) The silica wet gel peripheral solvent system is subjected to phase separation to separate a lower water phase, and at the moment, the inner surfaces of the silica wet gel pores are siliconized to be hydrophobic, so that the silica wet gel pores are mainly n-hexane and contain part of isopropanol.
(5) And drying the obtained silica wet gel at room temperature for 10-12 h to obtain the silica aerogel.
In a preferred embodiment of the present application, the ion exchange column has a diameter of 8cm and a length of 40cm, and the ion exchange resin is a Dowex hydrogen type cation exchange resin. The preferred active silica sol has a pH of 2.7.
In the preferred embodiment of the application, ammonia water is used as a catalyst, the catalytic activity silicic acid is polymerized to form silica wet gel with a space network structure, the speed of forming silica gel by ammonia water with different concentrations is different, meanwhile, the pH value of the silica sol is controlled by ammonia water, and the gelation speed of the silica sol with different pH values is different. Generally, the pH is between 3.5 and 5.0, and the silica sol-gel speed becomes faster as the pH increases; the silica sol with the pH value of 5.0-9.0 is easy to form gel and difficult to control; at pH above 9.0, silica sol gel speeds are getting slower. In order to easily control the pH value and the gel speed, even without introducing excessive external ions to influence the gelation speed, the pH value of the silica sol controlled by the ammonia water is 4.0, the gel time is about 8-12 h, and the relatively fine silica wet gel is formed. The aging process used in the application is carried out at room temperature and in deionized water for 20-28 h.
In a preferred embodiment of the application, in order to continuously carry out the cyclic reaction of the isopropanol/trimethylchlorosilane/n-hexane system with the hydroxyl groups on the inner surface of the pores of the silica wet gel and the water in the pores of the silica wet gel, the inner surface of the silica wet gel is completely modified to be hydrophobic as much as possible, and meanwhile, the solvent on the periphery of the silica wet gel realizes phase separation, namely an aqueous phase (hydrochloric acid aqueous solution) and an oil phase (n-hexane). Thus, the amount of trimethylchlorosilane used in the present application is most critical. Experiments show that the optimal molar ratio of the trimethylchlorosilane, the isopropanol to the water in the silica wet gel pores is (1-2): (4-5), and the volume ratio of the n-hexane to the trimethylchlorosilane is 8-10:1.
In the step (4) of the application, for the solvent system on which the peripheral phase separation of the silica wet gel is realized, the hydrochloric acid system generated after the reaction and water are positioned at the lower layer, the n-hexane phase is positioned at the upper layer, and the silica wet gel is positioned at the bottom of the n-hexane phase, so that the water at the lower layer can be completely removed by a liquid phase separation method, and simultaneously, the n-hexane layer on the periphery of the silica wet gel can be removed without recovering the solvent by high-temperature distillation.
In step (5) of the present application, for the silica wet gel which has achieved the phase separation of the solvent, except that the inner surface has been modified to be hydrophobic, the solvent in the pores is n-hexane solvent having a small capillary pressure, and thus it is only necessary to dry at room temperature without forming a silica aerogel having collapsed pores.
The principles and features of the present application are described below in connection with the following examples, which are set forth to illustrate, but are not to be construed as limiting the scope of the application. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
Example 1
The embodiment discloses a method for preparing silica aerogel based on water glass, which comprises the following steps:
(1) 30wt% water glass with the modulus of 3.3 is used as a silicon source, deionized water is used for dilution to 8wt%, the diluted water glass is subjected to ion exchange through cation exchange resin, and cation impurities in the solution are removed, so that the active silica sol is prepared, and the pH is controlled at 2.7.
(2) When the pH value of the prepared active silica sol is adjusted to 4.0 by using 0.5M ammonia water solution as a catalyst, stirring is continued for 30 seconds, then the active silica sol is transferred into a polypropylene small bottle, and the active silica sol is kept stand for 10 hours after sealing to form the silica hydrogel. To strengthen the gel structure, the resulting silica hydrogel was aged in deionized water for 24 hours to obtain a silica wet gel.
(3) The aged silica wet gel is soaked in the mixed solution of isopropanol/trimethylchlorosilane/n-hexane, and after a period of time, the peripheral solvent of the silica wet gel is subjected to phase separation, and the siliconized silica wet gel is positioned at the bottom of the upper n-hexane oil phase. Wherein, the optimal mole ratio of trimethylchlorosilane, isopropanol and water in the silica wet gel pore is 1:1:4, and the volume ratio of n-hexane to trimethylchlorosilane is 8:1.
(4) The silica wet gel peripheral solvent system is subjected to phase separation to separate a lower water phase, and at the moment, the inner surfaces of the silica wet gel pores are siliconized to be hydrophobic, so that the silica wet gel pores are mainly n-hexane and contain part of isopropanol.
(5) The obtained silica wet gel was dried at room temperature for 12 hours to obtain a silica aerogel.
Example 2
The embodiment discloses a method for preparing silica aerogel based on water glass, which comprises the following steps:
(1) And (3) using water glass as a silicon source, performing ion exchange on the diluted water glass through cation exchange resin, and removing cation impurities in the solution to prepare the active silica sol, wherein the pH is controlled at 3.
(2) And (3) using 1.0M ammonia water solution as a catalyst, continuously stirring for 40s when the pH value of the prepared active silica sol is regulated to be 4.0, transferring the active silica sol into a polypropylene small bottle, sealing, and standing for 8 hours to form the silica hydrogel. To strengthen the gel structure, the resulting silica hydrogel was aged in deionized water for 20 hours to obtain a silica wet gel.
(3) The aged silica wet gel is soaked in the mixed solution of isopropanol/trimethylchlorosilane/n-hexane, and after a period of time, the peripheral solvent of the silica wet gel is subjected to phase separation, and the siliconized silica wet gel is positioned at the bottom of the upper n-hexane oil phase. Wherein, the optimal mole ratio of trimethylchlorosilane, isopropanol and water in the silica wet gel pore is 2:2:5, and the volume ratio of n-hexane to trimethylchlorosilane is 9:1.
(4) The silica wet gel peripheral solvent system is subjected to phase separation to separate a lower water phase, and at the moment, the inner surfaces of the silica wet gel pores are siliconized to be hydrophobic, so that the silica wet gel pores are mainly n-hexane and contain part of isopropanol.
(5) The obtained silica wet gel was dried at room temperature for 10 hours to obtain silica aerogel.
Example 3
The embodiment discloses a method for preparing silica aerogel based on water glass, which comprises the following steps:
(1) And (3) taking the water glass as a silicon source, carrying out ion exchange on the diluted water glass through cation exchange resin, and removing cation impurities in the solution to prepare the active silica sol, wherein the pH is controlled at 2.1.
(2) When the pH value of the prepared active silica sol is adjusted to 4.0 by using 0.75M ammonia water solution as a catalyst, stirring is continued for 20 seconds, then the active silica sol is transferred into a polypropylene vial, and the active silica sol is sealed and then stands for 8 hours to form the silica hydrogel. To strengthen the gel structure, the resulting silica hydrogel was aged in deionized water for 20 hours to obtain a silica wet gel.
(3) The aged silica wet gel is soaked in the mixed solution of isopropanol/trimethylchlorosilane/n-hexane, and after a period of time, the peripheral solvent of the silica wet gel is subjected to phase separation, and the siliconized silica wet gel is positioned at the bottom of the upper n-hexane oil phase. Wherein, the optimal molar ratio of trimethylchlorosilane, isopropanol and water in the silica wet gel pores is 2:1:4, and the volume ratio of n-hexane to trimethylchlorosilane is 10:1.
(4) The silica wet gel peripheral solvent system is subjected to phase separation to separate a lower water phase, and at the moment, the inner surfaces of the silica wet gel pores are siliconized to be hydrophobic, so that the silica wet gel pores are mainly n-hexane and contain part of isopropanol.
(5) The obtained silica wet gel was dried at room temperature for 12 hours to obtain a silica aerogel.
Comparative example
The comparative example discloses a method for preparing silica aerogel, which is different from the method in the embodiment 1 in that the solvent system in the step (3) is an isopropanol/n-hexane system, and the rest methods are consistent.
A schematic view and SEM image of the silica aerogel prepared in example 1 are shown in fig. 1 (a) and 1 (c), respectively, and fig. 1 (a) shows that a transparent monolithic silica aerogel is formed, from which it can be seen that the monolithic transparent silica aerogel consists of silica nanoparticles like a gas phase.
Schematic good SEM images of the silica aerogel prepared in the comparative example are shown in fig. 1 (b) and 1 (d), respectively, and fig. 1 (b) shows that the silica aerogel prepared by the conventional solvent exchange method is not easily formed into a whole block shape, is very fragile, and is easily cracked because the nano particles constituting the silica aerogel are very large and are not uniform.
The parameters of the silica aerogels prepared in example 1 and comparative example are shown in table 1.
TABLE 1 physical Properties parameters of silica aerogels prepared with different drying solvent systems
As can be seen from Table 1, the silica aerogel prepared by the method of the present application has the characteristics of large specific surface area, smaller average pore diameter and larger pore volume compared with the silica aerogel prepared by the conventional solvent exchange method.
The foregoing is only a specific embodiment of the application to enable those skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. A method for preparing silica aerogel based on water glass, which is characterized by comprising the following steps:
taking water glass as a silicon source, and performing ion exchange with cation exchange resin to obtain active silica sol;
ammonia water solution is used as a catalyst, the pH value of the active silica sol is regulated, and the solution is continuously stirred, sealed and kept stand to prepare crude silica aerogel;
soaking the aged crude silica aerogel in a mixed solution, and carrying out phase separation to obtain siliconized silica wet gel;
and drying the siliconized silica wet gel at room temperature to obtain the silica aerogel.
2. The method for preparing silica aerogel based on water glass according to claim 1, wherein the modulus of the water glass is 3.0-3.5 and the concentration is 8-30 wt%.
3. The method for preparing silica aerogel based on water glass according to claim 1, wherein the pH value of the active silica sol is 2.0-3.0.
4. The method for preparing silica aerogel based on water glass according to claim 1, wherein the concentration of the ammonia water solution is 0.5-1.0M, and the pH value of the active silica sol adjusted by the ammonia water solution is 4.0.
5. The method for preparing silica aerogel based on water glass according to claim 1, wherein the continuous stirring time is 20-40 s, the sealing and standing time is 8-12 h, and the aging time is 20-28 h.
6. The method for preparing silica aerogel based on water glass according to claim 1, wherein the crude silica aerogel is aged to be silica wet gel, the mixed solution is a mixed solution of isopropanol, trimethylchlorosilane and n-hexane, the molar ratio of the trimethylchlorosilane, the isopropanol and water in the pores of the silica wet gel is 1-2:1-2:4-5, and the volume ratio of the n-hexane to the trimethylchlorosilane is 8-10:1.
CN202310894157.2A 2023-07-19 2023-07-19 Method for preparing silicon dioxide aerogel based on water glass Pending CN116986600A (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100705587B1 (en) * 2006-07-25 2007-04-09 한국에너지기술연구원 Method of manufacturing aerogels using sodium silicate and aerogel tiles for making same method
CN101244824A (en) * 2007-02-15 2008-08-20 中国船舶重工集团公司第七二五研究所 Method for producing silica aerogel

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100705587B1 (en) * 2006-07-25 2007-04-09 한국에너지기술연구원 Method of manufacturing aerogels using sodium silicate and aerogel tiles for making same method
CN101244824A (en) * 2007-02-15 2008-08-20 中国船舶重工集团公司第七二五研究所 Method for producing silica aerogel

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
耿刚强等: "低密度纳米孔二氧化硅气凝胶的制备工艺", 《长安大学学报（自然科学版）》, vol. 30, no. 4, pages 107 - 110 *

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