Hollow carbon fiber-reinforced carbon aerogel composite material and preparation method and application thereof

Abstract

The present application belongs to the technical field of carbon-carbon composite materials, and provides a hollow carbon fiber reinforced carbon aerogel composite material, a preparation method and application thereof. The preparation method comprises the following steps: mixing a phenolic monomer, an aldehyde monomer, a metal ion catalyst and an alcohol solvent to obtain a mixed solution; soaking a viscose-based fiber felt in the mixed solution, and then performing a sol-gel reaction to obtain a composite material precursor; and sequentially performing normal pressure drying and carbonization reaction on the composite material precursor to obtain the hollow carbon fiber reinforced carbon aerogel composite material. In the carbonization process, the present application successfully constructs a carbon fiber reinforcement body with a hollow structure through the shrinkage difference between the fiber and the resin, and the metal ion catalyst has a pore-forming effect, so that the prepared hollow carbon fiber reinforced carbon aerogel composite material has high mechanical properties and a large specific surface area, and the problems of poor mechanical properties of a phenolic resin-based carbon aerogel and incompatibility between mechanical properties and pore structure are solved.

Description

Technical Field

[0001] This invention relates to the field of carbon-carbon composite materials technology, and in particular to a hollow carbon fiber reinforced carbon aerogel composite material, its preparation method, and its application. Background Technology

[0002] In recent years, with industrial development, water pollution has become increasingly serious. Major pollutants include organic dyes, waste oils, and heavy metal ions, posing a serious threat to human health. Therefore, materials with high adsorption capacity are needed to treat these pollutants. In current research, activated carbon, carbon aerogels, carbon fibers, and polymer-derived carbon are common adsorption materials. Among them, carbon aerogels have significant advantages in wastewater treatment due to their lightweight, porous nature, and large specific surface area (a method for preparing graphene-containing highly adsorbent plant protein carbon aerogel, CN112661154B).

[0003] Currently, the main precursor materials for preparing carbon aerogels include phenolic resins, biomass, and carbon nanotubes / graphene. Among these, phenolic resins, as a mature industrial raw material, facilitate the large-scale production of carbon aerogels. For phenolic resin-based carbon aerogels, an alkaline initiator is typically used to initiate the gel-sol reaction, thereby obtaining the carbon aerogel precursor. Subsequent steps such as aging, solvent replacement, drying, carbonization, and activation are required to finally obtain the carbon aerogel. However, this process suffers from long cycles, complex procedures, and high costs. Furthermore, specialized drying processes such as supercritical drying and freeze-drying are costly and hinder their development. In contrast, atmospheric pressure drying can reduce costs, but it leads to volume shrinkage, affecting the final pore structure and adsorption performance of the carbon aerogel.

[0004] Furthermore, carbon aerogels exhibit poor mechanical properties, hindering their recycling. Some researchers have attempted to improve mechanical properties by introducing fiber reinforcements into the system (a method for preparing high-strength and tough carbon aerogel composites through fiber softening effect, CN116573948A; a carbon fiber / biomass-based sugar carbon aerogel high-efficiency thermal insulation material and its ionothermal preparation method, CN116675551A). However, the introduction of fiber materials significantly reduces the specific surface area, affecting the adsorption performance of the final material. Therefore, developing a carbon aerogel composite material with a large specific surface area and excellent mechanical properties is of great significance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art by providing a hollow carbon fiber reinforced carbon aerogel composite material, its preparation method, and its application.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing hollow carbon fiber reinforced carbon aerogel composite material, comprising the following steps:

[0008] 1) A mixed solution is obtained by mixing phenolic monomers, aldehyde monomers, metal ion catalysts, and alcohol solvents;

[0009] 2) The viscose-based fiber felt was immersed in the mixed solution to carry out the sol-gel reaction and obtain the composite material precursor;

[0010] 3) The composite precursor was sequentially subjected to atmospheric pressure drying and carbonization reaction to obtain hollow carbon fiber reinforced carbon aerogel composite material.

[0011] The phenolic monomers include one or more of phloroglucinol, hydroquinone, and 3-aminophenol; the aldehyde monomers include one or more of 2-pyrrolecarboxaldehyde, 2-thiophenecarboxaldehyde, and 2-furancarboxaldehyde; the metal ion catalysts include one or more of zinc bromide and zinc acetate; and the alcohol solvents include one or more of isopropanol, n-propanol, and n-butanol.

[0012] Preferably, the molar ratio of the phenolic monomer, aldehyde monomer, metal ion catalyst and alcohol solvent is 1:1.5-6.0:3.2-8.0:20.0-52.0.

[0013] Preferably, the mixing speed in step 1) is 200-400 rpm, the mixing time is 20-60 min, and the mixing temperature is 20-50℃.

[0014] Preferably, the soaking temperature in step 2) is 20–50°C and the soaking time is 10–60 min; the sol-gel reaction temperature is 40–70°C and the sol-gel reaction time is 8–24 h.

[0015] Preferably, the temperature for atmospheric pressure drying in step 3) is 80–120°C, and the drying time is 10–24 h.

[0016] Preferably, the carbonization reaction temperature in step 3) is 400–1000°C, the carbonization reaction time is 1–4 h, and the heating rate from room temperature to the carbonization reaction temperature is 1–10°C / min.

[0017] Preferably, the products of the carbonization reaction in step 3) are sequentially washed with water and dried to obtain hollow carbon fiber reinforced carbon aerogel composite material; the number of water washings is 2 to 4, and the time for each water washing is 2 to 6 minutes; the drying temperature is 60 to 120°C, and the drying time is 10 to 24 hours.

[0018] The present invention also provides a method for preparing hollow carbon fiber reinforced carbon aerogel composite material to obtain hollow carbon fiber reinforced carbon aerogel composite material.

[0019] Preferably, the specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material is 700–2000 m². 2 / g, compressive strength is 0.06~0.2MPa, and compressive modulus is 0.3~1.1MPa.

[0020] The present invention also provides the application of the hollow carbon fiber reinforced carbon aerogel composite material in adsorption, energy storage and thermal insulation.

[0021] The beneficial effects of this invention include the following:

[0022] 1) In the preparation of the composite material precursor, the present invention uniformly wraps the viscose-based fiber felt in phenolic resin by in-situ impregnation; during the carbonization process, the carbon fiber reinforcement with a hollow structure is successfully constructed by the shrinkage difference between the fiber and the resin; and carbon aerogel composite material with both high mechanical properties and large specific surface area is obtained by the pore-forming effect of metal ion catalyst, thus solving the problems of poor mechanical properties and incompatibility between mechanical properties and pore structure of carbon aerogel.

[0023] 2) By introducing alcohol solvents and metal ion catalysts into the preparation process of composite material precursors, the polymer particle size is controlled at the micron level. This not only accelerates the reaction rate and shortens the sol-gel reaction time, enabling micron-sized resin particles to grow uniformly on the fiber surface, but also eliminates the need for solvent replacement, thus reducing the volume shrinkage rate under normal pressure drying.

[0024] 3) By adjusting process parameters such as raw material ratio, sol-gel reaction temperature and time, and carbonization temperature and time, this invention can achieve precise control over the mechanical properties, pore size distribution, and porosity of hollow carbon fiber reinforced carbon aerogel composite materials.

[0025] 4) This invention uses atmospheric pressure drying instead of special drying, and eliminates the need for solvent replacement and secondary activation processes, simplifying the preparation process and providing an effective method for the large-scale production of carbon fiber reinforced carbon aerogel composites. Attached Figure Description

[0026] Figure 1 This is a nitrogen adsorption test diagram of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1;

[0027] Figure 2 SEM image of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1;

[0028] Figure 3The X-ray diffraction spectrum of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 is shown below.

[0029] Figure 4 The Raman spectrum of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 is shown below.

[0030] Figure 5 This is a comparison chart of the adsorption amounts of methylene blue, oil, and water on the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1.

[0031] Figure 6 This is a schematic diagram of the compression of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1.

[0032] Figure 7 The image shows the compressive stress-strain curve of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1. Detailed Implementation

[0033] This invention provides a method for preparing hollow carbon fiber reinforced carbon aerogel composite material, comprising the following steps:

[0034] 1) A mixed solution is obtained by mixing phenolic monomers, aldehyde monomers, metal ion catalysts, and alcohol solvents;

[0035] 2) The viscose-based fiber felt was immersed in the mixed solution to carry out the sol-gel reaction and obtain the composite material precursor;

[0036] 3) The composite precursor was sequentially subjected to atmospheric pressure drying and carbonization reaction to obtain hollow carbon fiber reinforced carbon aerogel composite material.

[0037] The phenolic monomers include one or more of phloroglucinol, hydroquinone, and 3-aminophenol; the aldehyde monomers include one or more of 2-pyrrolecarboxaldehyde, 2-thiophenecarboxaldehyde, and 2-furancarboxaldehyde; the metal ion catalysts include one or more of zinc bromide and zinc acetate; and the alcohol solvents include one or more of isopropanol, n-propanol, and n-butanol.

[0038] In this invention, the molar ratio of the phenolic monomer, aldehyde monomer, metal ion catalyst, and alcohol solvent is preferably 1:1.5-6.0:3.2-8.0:20.0-52.0, more preferably 1:2-4.0:3.6-7.0:25.0-42.8, and even more preferably 1:2.3-2.5:4.5-5.0:35.0-42.0.

[0039] In this invention, the mixing speed in step 1) is preferably 200-400 rpm, more preferably 250-350 rpm, and even more preferably 300 rpm; the mixing time is preferably 20-60 min, more preferably 30-50 min, and even more preferably 35-40 min; the mixing temperature is preferably 20-50℃, more preferably 25-45℃, and even more preferably 30-40℃.

[0040] In this invention, the soaking temperature in step 2) is preferably 20-50°C, more preferably 25-45°C, and even more preferably 30-40°C; the soaking time is preferably 10-60 min, more preferably 15-40 min, and even more preferably 20-30 min.

[0041] In this invention, the temperature of the sol-gel reaction in step 2) is preferably 40-70°C, more preferably 55-65°C, and even more preferably 60°C; the time of the sol-gel reaction is preferably 8-24 h, more preferably 10-18 h, and even more preferably 12-14 h.

[0042] In this invention, the sol-gel reaction is preferably carried out in a sealed container.

[0043] In this invention, the temperature of atmospheric pressure drying in step 3) is preferably 80-120°C, more preferably 90-110°C, and even more preferably 100-105°C; the time of atmospheric pressure drying is preferably 10-24h, more preferably 12-18h, and even more preferably 14-16h.

[0044] In this invention, the temperature of the carbonization reaction in step 3) is preferably 400-1000℃, more preferably 600-800℃, and even more preferably 700℃; the carbonization reaction time is preferably 1-4h, more preferably 2-3h, and even more preferably 2.5h; the heating rate from room temperature to the carbonization reaction temperature is preferably 1-10℃ / min, more preferably 2-8℃ / min, and even more preferably 3-5℃ / min.

[0045] In this invention, the carbonization reaction is preferably carried out under a protective atmosphere, preferably a nitrogen atmosphere.

[0046] In this invention, the product of the carbonization reaction in step 3) is preferably washed with water and dried sequentially to obtain a hollow carbon fiber reinforced carbon aerogel composite material; the number of water washings is preferably 2 to 4 times, more preferably 3 times; the time for each water washing is preferably 2 to 6 minutes, more preferably 3 to 5 minutes, and more preferably 4 minutes; the drying temperature is preferably 60 to 120°C, more preferably 80 to 110°C, and more preferably 90 to 100°C; the drying time is preferably 10 to 24 hours, more preferably 11 to 18 hours, and more preferably 12 to 13 hours.

[0047] The present invention also provides a method for preparing hollow carbon fiber reinforced carbon aerogel composite material to obtain hollow carbon fiber reinforced carbon aerogel composite material.

[0048] In this invention, the specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material is 700–2000 m². 2 The compressive strength is preferably 0.06-0.2 MPa, and the compressive modulus is 0.3-1.1 MPa.

[0049] The present invention also provides the application of the hollow carbon fiber reinforced carbon aerogel composite material in adsorption, energy storage and thermal insulation.

[0050] In this invention, hollow carbon fiber reinforced carbon aerogel composite material is preferably used for adsorbing methylene blue, oil, and water.

[0051] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0052] In this embodiment, the viscose-based fiber mat was self-made, using viscose short fibers with a fineness of 1.6 dtex and a length of 38 mm as raw materials. The thickness of the viscose-based fiber mat was 16 mm, and the basis weight was 2200 g / m². 2 .

[0053] Example 1

[0054] Phloroglucinol, 2-pyrrole formaldehyde, zinc acetate, and isopropanol were added sequentially to a beaker and stirred at 300 rpm and 45°C for 40 min to obtain a mixed solution; the molar ratio of phloroglucinol, 2-pyrrole formaldehyde, zinc acetate, and isopropanol was 1:2:3.2:42.8. Viscose-based fiber felt was immersed in the above mixed solution at 45°C for 20 min, then placed in a sealed container and subjected to a sol-gel reaction at 60°C for 12 h to obtain the composite material precursor.

[0055] The composite precursor was dried at 100℃ under normal pressure for 12 hours, and then heated from room temperature to 1000℃ at a rate of 5℃ / min under a high-purity nitrogen atmosphere, and carbonized at 1000℃ for 2 hours. The carbonized material was washed with water three times, with each wash lasting 3 minutes. After washing, it was dried at 100℃ for 12 hours to obtain the hollow carbon fiber reinforced carbon aerogel composite material.

[0056] The specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 was 1990 m². 2 / g, compressive strength is 0.12MPa, and compressive modulus is 0.3MPa.

[0057] The hollow carbon fiber reinforced carbon aerogel composite material of Example 1 was tested for its adsorption capacity for methylene blue, chloroform, and water using a UV-Vis spectrophotometer and an electronic balance. The tests showed that the hollow carbon fiber reinforced carbon aerogel composite material adsorbed 411.02 mg / g of a 0.5 g / L methylene blue aqueous solution over 24 hours, 11.3 g / g of chloroform over 24 hours, and 5.9 g / g of water over 24 hours.

[0058] Nitrogen adsorption tests were performed on the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1. The sample was degassed at 180℃ for 12 hours before the test. The test program was set to whole-pore analysis, and the P / P0 range was set to 0.1–1.0. The test results are as follows: Figure 1 As shown, by Figure 1 As can be seen, the adsorption curve is a typical type IV adsorption isotherm, indicating that the hollow carbon fiber reinforced carbon aerogel composite material has a rich mesoporous and microporous structure. The SEM image of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 is shown below. Figure 2 As shown, by Figure 2 As can be seen, the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 possesses hollow carbon fibers and abundant pores. The X-ray diffraction spectrum of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 is shown below. Figure 3 As shown, by Figure 3 As can be seen, the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 exhibits obvious carbon diffraction peaks between 20° and 30°. The Raman spectrum of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 is shown below. Figure 4 As shown, by Figure 4 It can be seen that the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 has a performance of 1350 cm⁻¹ -1 and 1600cm -1 There was obvious sp nearby 2 with sp 3 Hybridized carbon type, I D / IG <1, indicating a high degree of graphitization. The adsorption process of methylene blue over time in the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 is as follows: Figure 5 As shown, by Figure 5 It can be seen that the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 has excellent adsorption capacity for methylene blue. A schematic diagram of the compression of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 is shown below. Figure 6 As shown, the pressure is 200g and the time is 10min, from Figure 6 It can be seen that the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 showed no damage under compression with a 200g weight, and the compression time was greater than 10 minutes; the compressive stress-strain curve of the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 is shown in the figure below. Figure 7 As shown, by Figure 6 and Figure 7 It can be seen that the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 1 has good compressibility.

[0059] Example 2

[0060] Hydroquinone, 2-furanaldehyde, zinc bromide, and n-propanol were sequentially added to a beaker and stirred at 400 rpm and 50°C for 50 min to obtain a mixed solution; the molar ratio of hydroquinone, 2-furanaldehyde, zinc bromide, and n-propanol was 1:2.3:3.6:42.0. Viscose-based fiber felt was immersed in the above mixed solution at 50°C for 15 min, then placed in a sealed container and subjected to a sol-gel reaction at 55°C for 14 h to obtain the composite material precursor.

[0061] The composite precursor was dried at 100℃ under normal pressure for 14 hours, and then heated from room temperature to 800℃ at a rate of 3℃ / min under a high-purity nitrogen atmosphere, and carbonized at 800℃ for 2 hours. The carbonized material was washed with water 4 times, with each wash lasting 2 minutes. After washing, it was dried at 110℃ for 10 hours to obtain the hollow carbon fiber reinforced carbon aerogel composite material.

[0062] The specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 2 was 1588 m². 2 / g, compressive strength is 0.20MPa, and compressive modulus is 0.79MPa.

[0063] The hollow carbon fiber reinforced carbon aerogel composite material of Example 2 was tested for its adsorption capacity for methylene blue, chloroform, and water using a UV-Vis spectrophotometer and an electronic balance. The tests showed that the hollow carbon fiber reinforced carbon aerogel composite material adsorbed 367.52 mg / g of a 0.5 g / L methylene blue aqueous solution over 24 hours, 8.2 g / g of chloroform over 24 hours, and 4.8 g / g of water over 24 hours.

[0064] Example 3

[0065] Phloroglucinol, 2-pyrrole formaldehyde, zinc acetate, and n-butanol were added sequentially to a beaker and stirred at 350 rpm and 40°C for 30 min to obtain a mixed solution. The molar ratio of phloroglucinol, 2-pyrrole formaldehyde, zinc acetate, and n-butanol was 1:2.5:5.0:40.0. Viscose-based fiber felt was immersed in the above mixed solution at 40°C for 20 min. After immersion, it was placed in a sealed container and subjected to a sol-gel reaction at 65°C for 11 h to obtain the composite material precursor.

[0066] The composite precursor was dried at 110℃ under normal pressure for 16 hours, and then heated from room temperature to 600℃ at a rate of 5℃ / min under a high-purity nitrogen atmosphere, and carbonized at 600℃ for 3 hours. The carbonized material was washed twice with water, with each wash lasting 4 minutes. After washing, it was dried at 100℃ for 13 hours to obtain the hollow carbon fiber reinforced carbon aerogel composite material.

[0067] The specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 3 was 1564 m². 2 / g, compressive strength is 0.15MPa, and compressive modulus is 0.42MPa.

[0068] The hollow carbon fiber reinforced carbon aerogel composite material of Example 3 was tested for its adsorption capacity for methylene blue, chloroform, and water using a UV-Vis spectrophotometer and an electronic balance. The tests showed that the hollow carbon fiber reinforced carbon aerogel composite material adsorbed 321.08 mg / g of a 0.5 g / L methylene blue aqueous solution over 24 hours, 7.2 g / g of chloroform over 24 hours, and 4.9 g / g of water over 24 hours.

[0069] Example 4

[0070] Phloroglucinol, 2-thiophene formaldehyde, zinc acetate, and isopropanol were added sequentially to a beaker and stirred at 300 rpm and 40°C for 40 min to obtain a mixed solution. The molar ratio of phloroglucinol, 2-thiophene formaldehyde, zinc acetate, and isopropanol was 1:2.0:4.8:35.0. Viscose-based fiber felt was immersed in the above mixed solution at 40°C for 20 min. After immersion, it was placed in a sealed container and subjected to a sol-gel reaction at 70°C for 10 h to obtain the composite material precursor.

[0071] The composite precursor was dried at 100℃ under normal pressure for 18 hours, and then heated from room temperature to 800℃ at a rate of 5℃ / min under a high-purity nitrogen atmosphere, and carbonized at 800℃ for 2 hours. The carbonized material was washed twice with water, with each wash lasting 3 minutes. After washing, it was dried at 100℃ for 12 hours to obtain the hollow carbon fiber reinforced carbon aerogel composite material.

[0072] The specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 4 was 1592 m². 2 / g, compressive strength is 0.18MPa, and compressive modulus is 0.52MPa.

[0073] The hollow carbon fiber reinforced carbon aerogel composite material of Example 4 was tested for its adsorption capacity for methylene blue, chloroform, and water using a UV-Vis spectrophotometer and an electronic balance. The tests showed that the hollow carbon fiber reinforced carbon aerogel composite material adsorbed 255.92 mg / g of a 0.5 g / L methylene blue aqueous solution over 24 hours, 6.2 g / g of chloroform over 24 hours, and 4.9 g / g of water over 24 hours.

[0074] Example 5

[0075] 3-Aminophenol, 2-thiophenecarboxaldehyde, zinc acetate, and n-propanol were sequentially added to a beaker and stirred at 200 rpm and 50°C for 50 min to obtain a mixed solution; the molar ratio of 3-aminophenol, 2-thiophenecarboxaldehyde, zinc acetate, and n-propanol was 1:4.0:4.5:25.0. Viscose-based fiber felt was immersed in the above mixed solution at 50°C for 10 min, then placed in a sealed container and subjected to a sol-gel reaction at 60°C for 12 h to obtain the composite material precursor.

[0076] The composite precursor was dried at 110℃ under normal pressure for 16 hours, and then heated from room temperature to 400℃ at a rate of 2℃ / min under a high-purity nitrogen atmosphere, and carbonized at 400℃ for 1 hour. The carbonized material was washed with water three times, with each wash lasting 2 minutes. After washing, it was dried at 110℃ for 10 hours to obtain the hollow carbon fiber reinforced carbon aerogel composite material.

[0077] The specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 5 was 766 m². 2 / g, compressive strength is 0.06MPa, and compressive modulus is 0.30MPa.

[0078] The hollow carbon fiber reinforced carbon aerogel composite material of Example 5 was tested for its adsorption capacity for methylene blue, chloroform, and water using a UV-Vis spectrophotometer and an electronic balance. The tests showed that the hollow carbon fiber reinforced carbon aerogel composite material adsorbed 285.07 mg / g of a 0.5 g / L methylene blue aqueous solution over 24 hours, 4.2 g / g of chloroform over 24 hours, and 4.8 g / g of water over 24 hours.

[0079] Example 6

[0080] Phloroglucinol, 2-thiophene formaldehyde, zinc acetate, and n-butanol were sequentially added to a beaker and stirred at 300 rpm and 30°C for 50 min to obtain a mixed solution; the molar ratio of phloroglucinol, 2-thiophene formaldehyde, zinc acetate, and n-butanol was 1:5.0:6.0:45.0. Viscose-based fiber felt was immersed in the above mixed solution at 30°C for 50 min, then placed in a sealed container and subjected to a sol-gel reaction at 50°C for 18 h to obtain the composite material precursor.

[0081] The composite precursor was dried at 110℃ under normal pressure for 20 hours, and then heated from room temperature to 700℃ at a rate of 8℃ / min under a high-purity nitrogen atmosphere, and carbonized at 700℃ for 3 hours. The carbonized material was washed with water three times, with each wash lasting 3 minutes. After washing, it was dried at 80℃ for 18 hours to obtain the hollow carbon fiber reinforced carbon aerogel composite material.

[0082] The specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material prepared in Example 6 was 1558 m². 2 / g, compressive strength is 0.17MPa, and compressive modulus is 0.50MPa.

[0083] The hollow carbon fiber reinforced carbon aerogel composite material of Example 6 was tested for its adsorption capacity for methylene blue, chloroform, and water using a UV-Vis spectrophotometer and an electronic balance. The tests showed that the hollow carbon fiber reinforced carbon aerogel composite material adsorbed 381.17 mg / g of a 0.5 g / L methylene blue aqueous solution over 24 hours, 7.8 g / g of chloroform over 24 hours, and 5.0 g / g of water over 24 hours.

[0084] This invention introduces a metal ion catalyst and an alcohol solvent into the sol-gel reaction process of the composite material precursor, accelerating the reaction rate while precisely controlling the particle size of the phenolic resin, thereby shortening the sol-gel reaction time. Solvent replacement is unnecessary under normal pressure drying, reducing volume shrinkage. During the preparation of the composite material precursor, viscose-based fiber felt is uniformly wrapped in phenolic resin through in-situ impregnation, and a hollow carbon fiber reinforcement is constructed during carbonization by utilizing the shrinkage difference between the fiber and the resin. The pore-forming effect of the metal ion catalyst imparts high porosity to the composite material. Therefore, the resulting hollow carbon fiber reinforced carbon aerogel composite material possesses both high mechanical properties and a large specific surface area, exhibiting good adsorption performance and repeatable adsorption of methylene blue, oil, and water.

[0085] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a hollow carbon fiber reinforced carbon aerogel composite material, characterized in that, It includes the following steps: 1) A mixed solution is obtained by mixing phenolic monomers, aldehyde monomers, metal ion catalysts, and alcohol solvents; 2) The viscose-based fiber felt was immersed in the mixed solution to carry out the sol-gel reaction and obtain the composite material precursor; 3) The composite material precursor was sequentially subjected to atmospheric pressure drying and carbonization reaction to obtain hollow carbon fiber reinforced carbon aerogel composite material; The phenolic monomers include one or more of phloroglucinol, hydroquinone and 3-aminophenol; the aldehyde monomers include one or more of 2-pyrrolecarboxaldehyde, 2-thiophenecarboxaldehyde and 2-furancarboxaldehyde; the metal ion catalysts include one or more of zinc bromide and zinc acetate; and the alcohol solvents include one or more of isopropanol, n-propanol and n-butanol. The molar ratio of the phenolic monomer, aldehyde monomer, metal ion catalyst and alcohol solvent is 1:1.5~6.0:3.2~8.0:20.0~52.

0.

2. The method for preparing hollow carbon fiber reinforced carbon aerogel composite material according to claim 1, characterized in that, Step 1) The mixing speed is 200~400 rpm, the mixing time is 20~60 min, and the mixing temperature is 20~50℃.

3. The method for preparing hollow carbon fiber reinforced carbon aerogel composite material according to claim 2, characterized in that, Step 2) The soaking temperature is 20~50℃, and the soaking time is... The reaction time is 10~60 min; the temperature of the sol-gel reaction is 40~70℃, and the reaction time is 8~24 h.

4. The method for preparing hollow carbon fiber reinforced carbon aerogel composite material according to claim 3, characterized in that, Step 3) The temperature for atmospheric pressure drying is 80~120℃, and the drying time is 10~24h.

5. The method for preparing hollow carbon fiber reinforced carbon aerogel composite material according to claim 4, characterized in that, Step 3) The carbonization reaction temperature is 400~1000℃, the carbonization reaction time is 1~4h, and the heating rate from room temperature to the carbonization reaction temperature is 1~10℃ / min.

6. The method for preparing hollow carbon fiber reinforced carbon aerogel composite material according to any one of claims 3 to 5, characterized in that, Step 3) The products of the carbonization reaction are sequentially washed with water and dried to obtain hollow carbon fiber reinforced carbon aerogel composite material; the number of water washings is 2 to 4 times, and the time for each water washing is 2 to 6 minutes; the drying temperature is 60 to 120°C, and the drying time is 10 to 24 hours.

7. The hollow carbon fiber reinforced carbon aerogel composite material prepared by the method of any one of claims 1 to 6.

8. The hollow carbon fiber reinforced carbon aerogel composite material according to claim 7, characterized in that, The specific surface area of ​​the hollow carbon fiber reinforced carbon aerogel composite material is 700~2000 m². 2 / g, compressive strength is 0.06~0.2MPa, and compressive modulus is 0.3~1.1MPa.

9. The application of the hollow carbon fiber reinforced carbon aerogel composite material according to claim 7 or 8 in adsorption, energy storage and thermal insulation.

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