Method for preparing silicon dioxide aerogel felt under catalysis of acid ion exchange fibers

Abstract

The invention belongs to the technical field of aerogel preparation, and relates to a method for preparing a silicon dioxide aerogel felt through catalysis of acid ion exchange fibers. The method for preparing the silicon dioxide aerogel felt through catalysis of the acid ion exchange fibers comprises the steps that an aerogel base material fiber felt and an ion exchange fiber felt are stacked and rolled into a roll shape, and the roll shape is coaxially arranged on a reel arranged in a reaction kettle; injecting an aerogel precursor prepared in advance into the reaction kettle until the coiled material base material is immersed to form a gel aerogel fiber felt; immersing the fiber felt in a hexamethyldisiloxane hydrophobic modification liquid, heating and aging for a certain time, and discharging the modification liquid; and heating and drying the aerogel fiber felt by hot nitrogen air blast to obtain the finished product silicon dioxide aerogel felt. Through an acid ion exchange fiber catalysis process, the reaction condition is mild, the reaction rate is effectively improved, the production period is shortened, and the catalyst does not need to be separated, can be recycled for multiple times, is pollution-free and environment-friendly, and has a relatively large aerogel mass production prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of thermal insulation materials, and particularly relates to a method for preparing silica aerogel felt by catalysis of acid ion exchange fibers. BACKGROUND

[0002] The silica aerogel felt is a kind of material mainly composed of nano-porous structure silica aerogel, and has the characteristics of nano-porous structure, low density, low thermal conductivity, high specific surface area and the like.

[0003] The drying process of the silica aerogel is generally divided into supercritical drying and atmospheric drying. The supercritical drying process has low technical threshold and good drying effect, and is the most commonly used drying method at present, but the equipment is complex, and the operation and maintenance costs are high, which is not conducive to large-scale production. The atmospheric drying process has simple equipment and low investment, and is suitable for large-scale production, but has high technical difficulty and is not easy to enter.

[0004] The atmospheric drying is the most active and has great development prospect in the current research of the production technology of the aerogel. In the atmospheric drying, the surface modification plays a decisive role in preventing the structure from being damaged in the drying process, and the selection of the modifier and the catalyst has important significance for the preparation of the silica aerogel felt.

[0005] The patent application No. 201610134192.4 discloses a method for preparing silica aerogel felt, in which trimethylchlorosilane is used as a modifier for surface modification, and the silica aerogel felt with superhydrophobicity and low thermal conductivity is prepared by atmospheric drying. However, the product prepared by the method has high chlorine ion content, and needs to be washed repeatedly with a large amount of water to remove the residual chlorine ions in the product, which increases the wastewater treatment amount and production cost.

[0006] The patent application No. 202311263498.6 discloses a method for preparing silica aerogel material by atmospheric drying, in which hexamethyldisilazane is used as a modifier. However, due to the volatile and strong adsorption of the silazane molecule, the product has a pungent ammonia smell, the post-processing is complex, and the product performance is unstable.

[0007] The patent application No. 202311472216.3 discloses a superhydrophobic and reinforced silica aerogel felt and a preparation method thereof, in which hexamethyldisiloxane is used as a modifier, and the silica aerogel felt is prepared by atmospheric drying. However, the product performance is poor because no catalyst is used for catalytic modification. SUMMARY

[0008] In view of the above problems, the application provides a method for preparing silica aerogel felt by catalysis of acid ion exchange fibers.

[0009] To achieve the above object, the method for preparing silica aerogel felt by acid ion exchange fiber catalysis comprises the following steps: (1) Aerogel base material preparation: aerogel base material fiber felt and ion exchange fiber felt are stacked and rolled into a roll shape coaxially on the spool arranged in the reaction kettle, the fiber felt is wound around the roll while keeping the roll core in close contact with the shaft center, and the outer wall of the fiber felt is in contact with the wall surface of the reaction kettle.

[0010] (2) Aerogel precursor preparation: one or more organosilicon sources are mixed with water and alcohol according to a certain molar ratio, a hydrolysis catalyst is added, and after uniform mixing, the silicon source is hydrolyzed to form a silica sol, and then a gel catalyst is added.

[0011] (3) Sol-gel: the prepared aerogel precursor is injected into the reaction kettle by a pump, and the liquid is flooded into the fiber felt roll, and after sol-gel, the gel fiber felt is formed.

[0012] (4) Aging modification: a pump is used to inject a hydrophobic modification liquid into the reaction kettle, and the temperature is raised for a certain period of time, and then the liquid modification liquid is discharged.

[0013] (5) Normal pressure drying: after aging modification, preheated nitrogen is continuously introduced into the reaction kettle, the temperature is raised to evaporate the solvent until no liquid is discharged, and silica aerogel felt is obtained.

[0014] Preferably, the ion exchange fiber felt as the catalyst of the whole system comprises strong acid ion exchange fiber felt or weak acid ion exchange fiber felt. The strong acid ion exchange fiber felt is prepared by using polyphenylene sulfide fiber as raw material, 1,4-bis(bromomethyl) benzene as crosslinking agent, and then using anhydrous ferric chloride as catalyst for crosslinking and concentrated sulfuric acid for sulfonation.

[0015] In some preferred embodiments, the strong acid ion exchange fiber felt is prepared by using polyphenylene sulfide fiber as raw material, 1,4-bis(bromomethyl) benzene as crosslinking agent, mixing the crosslinking agent with excess tetrachloroethane, then immersing the polyphenylene sulfide fiber (molar ratio of polyphenylene sulfide to crosslinking agent is 5.5:1) for 12 hours of swelling, adding anhydrous ferric chloride catalyst (molar ratio of crosslinking agent to catalyst is 1:2.5) at a certain molar ratio, reacting at 100°C for 12 hours, washing with anhydrous ethanol, drying, then adding a mixture of chlorosulfonic acid and tetrachloroethane (molar ratio of intermediate fiber to chlorosulfonic acid is 1:3) at room temperature for 5 hours of reaction, washing with anhydrous ethanol, and drying to obtain strong acid ion exchange fiber.

[0016] Preferably, the stacking ratio of the ion exchange fiber felt and the aerogel base material fiber felt is 1 / (1-15) (such as winding 1 turn of ion exchange fiber felt corresponding to winding 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 turns of any one of the aerogel base material fiber felt).

[0017] The organic silicon source includes one or two of tetramethyl orthosilicate, tetraethyl orthosilicate, methyl triethoxysilane, polymethyl triethoxysilane, and preferably tetramethyl orthosilicate, tetraethyl orthosilicate or a mixture thereof.

[0018] The alcohol includes methanol, ethanol, and preferably ethanol.

[0019] The hydrolysis catalyst includes hydrochloric acid, nitric acid, sulfuric acid, acetic acid, and preferably hydrochloric acid.

[0020] The gel catalyst includes ammonia, potassium hydroxide, sodium hydroxide, and preferably potassium hydroxide.

[0021] Preferably, the organic silicon source is mixed with water, alcohol in a molar ratio of 1: (3-5) : (8-20), the hydrolysis catalyst is added in an amount of 10-50 ppm, and the gel catalyst is added in an amount of 2-10 times the hydrolysis catalyst.

[0022] The hydrophobic modification liquid includes dimethyl diethoxysilane, trimethyl ethoxysilane, trimethyl methoxysilane, and hexamethyldisiloxane, and preferably hexamethyldisiloxane.

[0023] Preferably, the aging modification temperature is 40-100°C, and the aging time is 4-24h.

[0024] The present application has the following advantages: (1) The method for preparing silica aerogel felt by using acidic ion exchange fiber as a catalyst provides a new method and idea for drying aerogel felt at normal pressure.

[0025] (2) The ion exchange fiber felt used as a hydrophobic modification catalyst has super strong contact with the aerogel base material fiber felt, avoids waste of impregnation glue due to excessively large pores, and can improve the utilization rate of raw materials. (3) The ion exchange fiber as a solid catalyst does not need to be separated and can be recycled multiple times, avoids the influence of catalyst residues on product performance, is pollution-free, and is environmentally friendly. (4) The ion exchange fiber as a catalyst has high reaction efficiency and mild reaction conditions. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The photos of the aerogel powder in Example 2, Comparative Example 1, Comparative Example 3, and Comparative Example 4 are included.

[0027] Figure 2 The photos of the first layer of the surface layer torn open in Example 2 and Comparative Example 4 are included.

[0028] The photos of the representative products in Example 2 and Comparative Examples 1, 3 and 4 of the present application and the intuitive diagrams of the hydrophobicity of the surface aerogel powder are shown in the table. The product photo is a photo of the first layer of the product after the surface layer is torn open, and the aerogel powder is the floating powder collected after the product surface is dried and then immersed in water. DETAILED DESCRIPTION

[0029] The present application will be further described in conjunction with specific examples. However, the scope of the present application is not limited to the scope of the examples.

[0030] The strong acid ion exchange fiber used in the present application is prepared by using polyphenylene sulfide fiber as raw material and 1,4-bis(bromomethyl)benzene as crosslinking agent. The crosslinking agent is mixed with excess tetrachloroethane, and then polyphenylene sulfide fiber (molar ratio of polyphenylene sulfide to crosslinking agent is 5.5:1) is immersed and swelled for 12 h. Anhydrous ferric chloride catalyst (molar ratio of crosslinking agent to catalyst is 1:2.5) is added in a certain molar ratio, and the mixture is reacted at 100°C for 12 h. After washing with anhydrous ethanol and drying, an intermediate fiber is obtained. A mixture of chlorosulfonic acid and tetrachloroethane (molar ratio of intermediate fiber to chlorosulfonic acid is 1:3) is added at room temperature and reacted for 5 h. After washing with anhydrous ethanol and drying, a strong acid ion exchange fiber is obtained.

[0031] Example 1 A method for preparing a silica aerogel felt by catalysis of an acidic ion exchange fiber, comprising the following steps: (1) Aerogel base material preparation: The strong acid ion exchange fiber felt and the aerogel base material fiber felt are stacked at a ratio of 1 / 5, and the stacked fiber felt is wound into a roll shape and placed coaxially on the spool in the reaction kettle. The fiber felt is wound while keeping the core in close contact with the shaft, and the outer wall of the fiber felt is in contact with the wall of the reaction kettle.

[0032] (2) Aerogel precursor preparation: Tetraethyl orthosilicate, ethanol and water are mixed in a molar ratio of 1:8:3, 50 ppm hydrochloric acid aqueous solution is added, and the mixture is stirred uniformly. Before impregnation, potassium hydroxide aqueous solution (molar ratio of potassium hydroxide to hydrochloric acid is 5 / 1) is added.

[0033] (3) Sol-gel: The prepared aerogel precursor is injected into the reaction kettle by pump, and the liquid is used to immerse the fiber felt roll. After sol-gel, a gel fiber felt is formed.

[0034] (4) Aging modification: Hexamethyldisiloxane, ethanol and water are mixed in a ratio of 100:20:1, and then added to the reaction kettle to immerse the gel fiber felt. The mixture is heated at 70°C for 8 h, and then the liquid modification solution is discharged.

[0035] (5) Atmospheric pressure drying: After aging modification, preheated nitrogen gas is continuously introduced into the reaction kettle, and the temperature is raised to 100°C to evaporate the solvent until no liquid is discharged, and a silica aerogel felt is obtained.

[0036] Example 2 A method for preparing silica aerogel felt by acidic ion exchange fiber catalysis, comprising the following steps: (1) Aerogel base material preparation: The strong acid ion exchange fiber felt and the aerogel base material fiber felt are stacked at a stacking ratio of 1 / 10, and are wound into a roll shape coaxially on the spool arranged in the reaction kettle. When the fiber felt is wound, the roll core is kept in close contact with the shaft core, and the outer wall of the fiber felt is in contact with the wall surface of the reaction kettle.

[0037] (2) Aerogel precursor preparation: Tetraethyl orthosilicate, ethanol and water are mixed uniformly at a molar ratio of 1:8:3, 50 ppm hydrochloric acid aqueous solution is added, and stirring is uniform. Before impregnation, potassium hydroxide aqueous solution (molar ratio of potassium hydroxide to hydrochloric acid is 5 / 1) is added.

[0038] (3) Sol-gel: The prepared aerogel precursor is injected into the reaction kettle by a pump, and the liquid submerges the fiber felt roll. After sol-gel, the gel fiber felt is formed.

[0039] (4) Aging modification: After aging modification, preheated nitrogen is continuously introduced into the reaction kettle, the temperature is raised to 100°C, and the solvent is evaporated until no liquid is discharged, thereby obtaining the silica aerogel felt.

[0040] (5) Normal pressure drying: After aging modification, preheated nitrogen is continuously introduced into the reaction kettle, the temperature is raised to 100°C, and the solvent is evaporated until no liquid is discharged, thereby obtaining the silica aerogel felt.

[0041] Example 3 A method for preparing silica aerogel felt by acidic ion exchange fiber catalysis, comprising the following steps: (1) Aerogel base material preparation: The strong acid ion exchange fiber felt and the aerogel base material fiber felt are stacked at a stacking ratio of 1 / 15, and are wound into a roll shape coaxially on the spool arranged in the reaction kettle. When the fiber felt is wound, the roll core is kept in close contact with the shaft core, and the outer wall of the fiber felt is in contact with the wall surface of the reaction kettle.

[0042] (2) Aerogel precursor preparation: Tetraethyl orthosilicate, ethanol and water are mixed uniformly at a molar ratio of 1:8:3, 50 ppm hydrochloric acid aqueous solution is added, and stirring is uniform. Before impregnation, potassium hydroxide aqueous solution (molar ratio of potassium hydroxide to hydrochloric acid is 5 / 1) is added.

[0043] (3) Sol-gel: The prepared aerogel precursor is injected into the reaction kettle by a pump, and the liquid submerges the fiber felt roll. After sol-gel, the gel fiber felt is formed.

[0044] (4) Aging modification: After aging modification, preheated nitrogen is continuously introduced into the reaction kettle, the temperature is raised to 100°C, and the solvent is evaporated until no liquid is discharged, thereby obtaining the silica aerogel felt.

[0045] (5) Atmospheric pressure drying: after aging modification, preheated nitrogen is continuously introduced into the reaction kettle, the temperature is raised to 100°C, the solvent is evaporated to no liquid is discharged, and a silica aerogel felt is obtained.

[0046] Example 4 A method for preparing a silica aerogel felt by catalysis of an acidic ion exchange fiber, comprising the following steps: (1) Weak acid ion exchange fiber felt pretreatment: the purchased carboxylic acid sodium type ion exchange fiber felt (Yk-S01 of Henan Yin Kai New Material Co., Ltd.) is placed in a 10% hydrochloric acid aqueous solution, soaked and replaced for 2 hours, then washed to neutral with deionized water, and dried to obtain the ion exchange fiber felt to be used.

[0047] (2) Aerogel base material preparation: the weak acid ion exchange fiber felt and the aerogel base material fiber felt are stacked at a stacking ratio of 1 / 10, and are wound into a roll shape coaxially on the spool arranged in the reaction kettle. When the fiber felt is wound, the roll core is in close contact with the shaft core, and the outer wall of the fiber felt is in contact with the wall surface of the reaction kettle.

[0048] (3) Aerogel precursor preparation: tetraethyl orthosilicate, ethanol and water are mixed uniformly at a molar ratio of 1:8:3, 50 ppm of hydrochloric acid aqueous solution is added, and stirring is uniform. Before impregnation, potassium hydroxide aqueous solution (molar ratio of potassium hydroxide to hydrochloric acid is 5 / 1) is added.

[0049] (4) Sol-gel: the prepared aerogel precursor is injected into the reaction kettle by a pump, and the liquid is flooded to the fiber felt roll. After sol-gel, a gel fiber felt is formed.

[0050] (5) Aging modification: after aging modification, preheated nitrogen is continuously introduced into the reaction kettle, the temperature is raised to 100°C, the solvent is evaporated to no liquid is discharged, and a silica aerogel felt is obtained.

[0051] (5) Atmospheric pressure drying: after aging modification, preheated nitrogen is continuously introduced into the reaction kettle, the temperature is raised to 100°C, the solvent is evaporated to no liquid is discharged, and a silica aerogel felt is obtained.

[0052] Comparative Example 1 A method for preparing a silica aerogel felt by catalysis of an acidic ion exchange fiber, comprising the following steps: (1) Aerogel base material preparation: the aerogel base material fiber felt is wound into a roll shape and placed on the spool arranged in the reaction kettle. When the fiber felt is wound, the roll core is in close contact with the shaft core, and the outer wall of the fiber felt is in contact with the wall surface of the reaction kettle.

[0053] (2) Aerogel precursor preparation: tetraethyl orthosilicate, ethanol, water were mixed uniformly at a molar ratio of 1:8:3, 50 ppm hydrochloric acid aqueous solution was added, and stirring was uniform, before impregnation, potassium hydroxide aqueous solution (molar ratio of potassium hydroxide to hydrochloric acid was 5 / 1) was added.

[0054] (3) Sol-gel: the prepared aerogel precursor was injected into the reactor by pump, and the liquid was flooded into the fiber felt roll, and the gel fiber felt was formed after sol-gel.

[0055] (4) Aging modification: hexamethyldisiloxane and ethanol were mixed at a ratio of 100:20, 1000 ppm triflic acid was added and stirred uniformly, and then the gel fiber felt was immersed in the reactor, heated to 70℃ and heated for 24 hours. The liquid modification liquid was discharged.

[0056] (5) Atmospheric pressure drying: after aging modification, preheated nitrogen was continuously introduced into the reactor, the temperature was increased to 100℃, the solvent was evaporated until no liquid was discharged, and the silica aerogel felt was obtained.

[0057] Comparative Example 2 A method for preparing a silica aerogel felt by catalyzing an acidic ion exchange fiber, comprising the following steps: (1) Aerogel substrate preparation: the aerogel substrate fiber felt was wound into a roll and placed on the spool in the reactor, the fiber felt was wound around the spool while keeping the core in close contact with the axis, and the outer wall of the fiber felt was in contact with the wall of the reactor.

[0058] (2) Aerogel precursor preparation: tetraethyl orthosilicate, ethanol, water were mixed uniformly at a molar ratio of 1:8:3, 50 ppm hydrochloric acid aqueous solution was added, and stirring was uniform, before impregnation, potassium hydroxide aqueous solution (molar ratio of potassium hydroxide to hydrochloric acid was 5 / 1) was added.

[0059] (3) Sol-gel: the prepared aerogel precursor was injected into the reactor by pump, and the liquid was flooded into the fiber felt roll, and the gel fiber felt was formed after sol-gel.

[0060] (4) Aging modification: hexamethyldisiloxane and ethanol were mixed at a ratio of 100:20, 1000 ppm concentrated hydrochloric acid was added and stirred uniformly, and then the gel fiber felt was immersed in the reactor, heated to 70℃ and heated for 24 hours. The liquid modification liquid was discharged.

[0061] (5) Atmospheric pressure drying: after aging modification, preheated nitrogen was continuously introduced into the reactor, the temperature was increased to 100℃, the solvent was evaporated until no liquid was discharged, and the silica aerogel felt was obtained.

[0062] Comparative Example 3 A method for preparing a silica aerogel felt by catalyzing an acidic ion exchange fiber, comprising the following steps: (1) Aerogel substrate preparation: The aerogel substrate fiber felt is wound into a roll and placed on the shaft provided in the reaction kettle. The fiber felt is wound around the shaft with the core in close contact with the shaft. The outer wall of the fiber felt is in contact with the wall of the reaction kettle.

[0063] (2) Aerogel precursor preparation: Mix tetraethyl orthosilicate, ethanol, and water in a molar ratio of 1:8:3. Add 50 ppm of hydrochloric acid solution and stir until uniform. Before impregnation, add potassium hydroxide solution (molar ratio of potassium hydroxide to hydrochloric acid is 5 / 1). (3) Sol-gel: Use a pump to inject the prepared aerogel precursor into the reaction kettle. The liquid submerges the fiber felt roll. After sol-gel, a gel fiber felt is formed.

[0064] (4) Aging modification: Add 1000 ppm of potassium hydroxide ethanol solution to hexamethyldisiloxane and stir until uniform. Add to the reaction kettle to immerse the gel fiber felt. Heat to 100°C with a condensation device for 24 hours. Drain the liquid modification solution.

[0065] (5) Atmospheric pressure drying: After aging modification, continuously introduce preheated nitrogen into the reaction kettle. Evaporate the solvent at 100°C until no liquid is discharged. Obtain a silica aerogel felt.

[0066] Comparative Example 4 A method for catalytically preparing a silica aerogel felt from an acidic ion exchange fiber, comprising the following steps: (1) Aerogel substrate preparation: The aerogel substrate fiber felt is wound into a roll and placed on the shaft provided in the reaction kettle. The fiber felt is wound around the shaft with the core in close contact with the shaft. The outer wall of the fiber felt is in contact with the wall of the reaction kettle.

[0067] (2) Aerogel precursor preparation: Mix tetraethyl orthosilicate, ethanol, and water in a molar ratio of 1:8:3. Add 50 ppm of hydrochloric acid solution and stir until uniform. Before impregnation, add potassium hydroxide solution (molar ratio of potassium hydroxide to hydrochloric acid is 5 / 1).

[0068] (3) Sol-gel: Use a pump to inject the prepared aerogel precursor into the reaction kettle. The liquid submerges the fiber felt roll. After sol-gel, a gel fiber felt is formed.

[0069] (4) Aging modification: Add 1000 ppm of potassium hydroxide ethanol solution to hexamethyldisiloxane and stir until uniform. Add to the reaction kettle to immerse the gel fiber felt. Heat to 100°C with a condensation device for 24 hours. Drain the liquid modification solution.

[0070] ​The present application mainly tests and compares from the water repellency, normal temperature thermal conductivity and appearance, and the test results are shown in Table 1. The water repellency test is tested according to GB / T 10299-2011, and the thermal conductivity is tested according to GB / T 10294-2008.

[0071] In order to verify the influence of the formula and process of the present application on the effect of the present application, the following results are obtained by comparing the process parameters, and the specific results are shown in Table 1: Table 1

[0072] The silica aerogel felt synthesized in the present application has a water repellency of >99%, a normal temperature thermal conductivity of <0.018 W / m*k, and a surface aerogel powder that is uniform and delicate. As can be seen from Table 1, the ion exchange fiber felt is used as a hydrophobic modification catalyst in the present application, which has super strong contact with the aerogel base fiber felt. By adding water to the hydrophobic modification liquid, the acid ions in the ion exchange fiber felt can be better ionized. By adding ethanol to the hydrophobic modification liquid, the compatibility of the hydrophobic modification liquid, ethanol and water solution can be improved, and the uniformity of the catalytic system can be ensured. The present application can improve the uniformity of the catalytic system by stacking and rolling the aerogel base fiber felt and the ion exchange fiber felt. However, too much use of ion exchange fiber felt will reduce the single-pot productivity, and too little use of ion exchange fiber felt will slightly reduce the catalytic effect. When the stacking ratio of ion exchange fiber felt to aerogel base fiber felt is 1 / 15, the normal temperature thermal conductivity is 0.0201 W / m*k, which is greater than 0.018 W / m*k. The 1 / 10 stacking and rolling effect is better.

[0073] The main conclusions of the comparison between Examples 1-3 and Example 4 and Comparative Examples 1-4 are as follows: 1) The strong acid ion exchange fiber felt is used as a hydrophobic modification catalyst, which has high reaction efficiency and mild reaction conditions. The product has a water repellency of 99.7% and a normal temperature thermal conductivity of 0.0116 W / m*k; 2) The strong acid catalyst has poor modification ability for hexamethyldisiloxane, and the tetramethylammonium hydroxide has almost no catalytic effect. The potassium hydroxide has certain catalytic effect, but only a part of the modification is performed. The main reason is that the boiling point of hexamethyldisiloxane limits the optimal activity temperature of the alkaline catalyst; 3) The acid catalyst such as triflic acid has poor solubility in hexamethyldisiloxane, and the generated water during the reaction process easily causes the catalyst to separate and deactivate, reducing the catalytic efficiency.

[0074] The above is only a preferred specific embodiment of the present application, but each embodiment does not contain only one independent technical solution. Any person skilled in the art can make equivalent substitutions or changes within the technical scope disclosed by the present application according to the technical solutions and inventive concepts of the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for the catalytic preparation of silica aerogel felts from acidic ion exchange fibers, characterized in that, It comprises the following steps: (1) Aerogel base material preparation: aerogel base material fiber felt and ion exchange fiber felt are stacked and rolled into a roll shape coaxially on the spool arranged in the reaction kettle, and the fiber felt is wound around the roll while keeping the roll core in close contact with the shaft center, and the outer wall of the fiber felt is in contact with the wall surface of the reaction kettle; (2) Aerogel precursor preparation: mix the organosilicon source with water and alcohol according to a certain molar ratio, add a hydrolysis catalyst, mix uniformly, then hydrolyze the silicon source to form a silica sol, and then add a gelation catalyst; (3) Sol-gel: inject the aerogel precursor into the reaction kettle, and submerge the fiber felt roll with liquid, then form a gel fiber felt after sol-gel; (4) Aging modification: inject a hydrophobic modification liquid into the reaction kettle, heat and age for a certain period of time, and then discharge the liquid modification liquid; (5) Normal pressure drying: after aging and modification, continuously introduce preheated nitrogen into the reaction kettle, evaporate the solvent by heating until no liquid is discharged, and obtain a silica aerogel felt.

2. The process for the catalytic preparation of silica aerogel felt from acidic ion exchange fibers according to claim 1, characterized in that: The ion exchange fiber felt comprises strong acid ion exchange fiber felt or weak acid ion exchange fiber felt.

3. The process for the catalytic preparation of silica aerogel felt from acidic ion exchange fibers according to claim 2, characterized in that: The strong acid ion exchange fiber felt is obtained by using polyphenylene sulfide fiber as raw material, 1,4-bis(bromomethyl)benzene as crosslinking agent, and then catalyzing crosslinking with anhydrous ferric chloride and sulfonating with concentrated sulfuric acid.

4. The process for the catalytic preparation of silica aerogel felt from acidic ion exchange fibers according to claim 2, characterized in that: The stacking ratio of the ion exchange fiber felt to the aerogel base material fiber felt is 1 / (1-15).

5. The process for the catalytic preparation of silica aerogel felt from acidic ion exchange fibers according to claim 1, characterized in that: The organosilicon source comprises one or a combination of more than one of tetramethyl orthosilicate, tetraethyl orthosilicate, methyl triethoxysilane, and polymethyl triethoxysilane, and is preferably tetramethyl orthosilicate, tetraethyl orthosilicate, or a mixture thereof.

6. The process for the catalytic preparation of silica aerogel felt from acidic ion exchange fibers according to claim 1, characterized in that: The alcohol comprises methanol or ethanol, and is preferably ethanol. The hydrolysis catalyst comprises hydrochloric acid, nitric acid, sulfuric acid, or acetic acid, and is preferably hydrochloric acid.

7. The method for continuously preparing silica aerogel felt at normal pressure according to claim 1, characterized in that: The gelation catalyst comprises ammonia, potassium hydroxide, or sodium hydroxide, and is preferably potassium hydroxide.

8. The process for the catalytic preparation of silica aerogel felt from acidic ion exchange fibers according to claim 1, characterized in that: The organosilicon source, water, and alcohol are mixed according to a molar ratio of 1:(3-5):(8-10), the hydrolysis catalyst is added in an amount of 10-50 ppm, and the gelation catalyst is added in an amount of 2-10 times that of the hydrolysis catalyst.

9. The process for the catalytic preparation of silica aerogel felt from acidic ion exchange fibers according to claim 1, characterized in that: The hydrophobic modification liquid comprises dimethyldiethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, and hexamethyldisiloxane, and is preferably hexamethyldisiloxane. The aging modification temperature is 40-100°C, and the aging time is 4-24h.

10. A silica aerogel felt catalytically prepared from an acidic ion exchange fiber, characterized by: The method is prepared by any one of claims 1-9.

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