A method for preparing single-walled carbon nanotube aerogels and its applications

Abstract

This invention belongs to the field of nanomaterials and slurry preparation technology, and relates to a method for preparing single-walled carbon nanotube aerogels and their applications. The method involves treating single-walled carbon nanotubes to obtain initially dispersed carbon nanotube powder, then peeling off the carbon caps from the carbon nanotube powder to obtain peeled carbon nanotube products. These peeled carbon nanotube products are then added to a mixed acid solution for acidification, followed by filtration and washing, and finally preparation to obtain a carbon nanotube slurry. This slurry is then gelled, and the resulting gel product is freeze-dried to obtain single-walled carbon nanotube aerogels. The obtained single-walled carbon nanotube aerogels have a 55% increased specific surface area. The gelled and freeze-dried aerogel blocks exhibit excellent methylene blue solution adsorption performance, with a removal efficiency exceeding 90% and a maximum adsorption capacity of 635 mg / g, making them adsorbent materials of significant commercial value.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nanomaterial preparation, and particularly relates to a preparation method of single-walled carbon nanotube aerogel and application thereof. BACKGROUND

[0002] With the development of the printing and dyeing industry, the treatment of dye wastewater is becoming increasingly serious. Dye wastewater has the characteristics of complex composition, high colority and high organic matter content. The current purpose of treating such dye wastewater is mainly to separate and remove colored substances, and then destroy these color-forming substances, so as to achieve decolorization and degradation. Common treatment methods at home and abroad at present include biological treatment, chemical oxidation and flocculation, adsorption and electrochemical treatment methods. The adsorption decolorization method can remove the dye from the water without destroying the structure of the dye. The use of activated carbon, macroporous resin, silicon polymer and other materials with high specific surface area has good removal effect, but activated carbon has obvious limitations in treating high-concentration hydrophobic dyes, and is difficult to recycle after adsorption saturation, and also faces the problem of treatment in the later period. Therefore, it is of great significance to develop an adsorption material with high adsorption rate, wide adaptability and easy regeneration for the treatment of dye wastewater in the current printing and dyeing industry.

[0003] Carbon nanotubes (CNT) have a hollow structure and high specific surface area, and are an ideal adsorption material, but in the actual preparation of carbon tube products, the end of a single carbon tube is often a closed carbon cap or a state of being "blocked" by a catalyst, which limits the role of the hollow structure. The surface of the carbon tube will form hydrophobicity, and the nanoscale carbon tube will also agglomerate in the solution, which greatly limits the adsorption performance of the carbon tube. The modification of the carbon tube by adding functional groups to the surface of the carbon tube can effectively improve its hydrophobicity. In the prior art, lanthanum-modified carbon nanotube hydrogel is prepared, which has good removal effect on phosphorus in wastewater, but the hydrogel material is easy to break and cannot be recycled when used as an adsorption material. The carbon tube is further treated to prepare an aerogel structure with a block body, which can well increase its application range. A nanofiber / carbon nanotube aerogel composite material is prepared by atmospheric drying, which can be used in the field of electromagnetic shielding, but the aerogel of this material needs to be supported by a fiber skeleton. A carbon nanotube aerogel for heat-conducting insulation gaskets is prepared by dispersing carbon nanotubes with carbon nitride precursors, and a second component is introduced. However, the hydrophilicity and adsorption of the above-mentioned carbon nanotube aerogel are not very ideal, and neither is a renewable adsorption material. SUMMARY

[0004] The present application discloses a preparation method of single-walled carbon nanotube aerogel and application thereof, to solve the above and other potential problems of the prior art.

[0005] In order to solve the above problems, the technical scheme of the present application is: a preparation method of single-walled carbon nanotube aerogel, which specifically comprises the following steps:

[0006] S1) treating single-walled carbon nanotubes to obtain initially dispersed carbon tube powder, and then performing carbon cap peeling treatment on the carbon tube powder to obtain a carbon tube product after peeling;

[0007] S2) taking out the carbon tube product after peeling in S1), adding it into a mixed acid solution for acidification treatment, and then performing suction filtration and washing on the carbon tube product after acidification treatment to obtain carbon tube slurry after adjustment;

[0008] S3) performing gel treatment on the carbon tube slurry obtained in S2), and taking out the obtained gel product to obtain single-walled carbon nanotube aerogel after freeze-drying.

[0009] Further, the specific steps of S1) are:

[0010] S1.1) performing mechanical shearing on single-walled carbon nanotubes prepared by arc discharge method to obtain initially dispersed carbon tube powder;

[0011] S1.2) immersing the carbon tube powder obtained in S1.1) into an etchant solution with a certain concentration according to a certain proportion, then performing suction filtration and drying on the immersed material, and then placing it into a reaction furnace for carbon cap peeling treatment to obtain a carbon tube product after peeling.

[0012] Further, the average particle size of the initially dispersed carbon nanotube powder in S1.1) is 30-150 μm;

[0013] Further, the single-walled carbon nanotubes prepared by arc discharge method have the following characteristics: initial purity of 45-75%, apparent density of 0.2-0.8 g / cm 3 , specific surface area of 350-800 m 2 / g, and Raman I G / I D of 50-85.

[0014] The concentration of the etchant solution in S1.2) is 0.1-5.0 mol / L, and the mass ratio of the carbon tube powder to the etchant is 1:(0.5-3.0).

[0015] The peeling treatment process is as follows: the heating rate is 2-15 ℃ / min, the treatment temperature is 600-1000 ℃, the holding time is 0.5-4 h, and inert atmosphere protection is adopted throughout the whole process.

[0016] Further, the etchant is at least one of zinc chloride, aluminum chloride, calcium chloride, calcium hydroxide, potassium hydroxide, sodium oxide and sodium amide.

[0017] The reactor is a tubular furnace.

[0018] Furthermore, the specific steps of S2) are as follows:

[0019] S2.1) The stripped carbon nanotube products are mixed with a mixed acid solution to prepare a mixed solution with a carbon nanotube product solid content of 0.02-0.5 g / L. The mixed solution is then refluxed at a temperature of 60-120℃ for 5-12 h to complete the acidification treatment and obtain carbon nanotube slurry.

[0020] S2.2) The carbon nanotube slurry obtained in S2.1) is then dispersed at high speed to obtain a carbon nanotube slurry with an average particle size of 10-50 μm and a concentration of 0.2-2 g / L.

[0021] Furthermore, the mixed acid solution is a mixed acid solution with a molar ratio of concentrated hydrochloric acid and concentrated nitric acid of (1.0 to 12.0): 1, diluted with water to a concentration of 0.5 to 8 mol / L.

[0022] Furthermore, the specific steps of S3) are as follows:

[0023] S3.1) First, add the complexing agent to the carbon nanotube slurry and mix thoroughly;

[0024] S3.2) At a temperature of 50–120°C for 10–48 h, gelation treatment is performed. The resulting gel product is then freeze-dried to obtain single-walled carbon nanotube aerogel.

[0025] Furthermore, the complexing agent is at least one of sodium citrate, sodium thiosulfate, sodium sulfite, sodium alginate, disodium diethylaminetetraacetate, sodium hexametaphosphate, and diethanolamine.

[0026] Furthermore, the density of the single-walled carbon nanotube aerogel is 0.3–1.0 kg / m³. 3 It has a porosity of over 80% and a specific surface area of ​​600–1300 m². 2 / g.

[0027] A single-walled carbon nanotube aerogel prepared by the above method is used in dye adsorption. Its removal efficiency for methylene blue reaches more than 90%, and the maximum adsorption capacity is 635 mg / g.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The carbon nanotubes are precisely peeled off by an etchant. After peeling, the carbon nanotubes have open carbon caps, forming an open structure, which greatly increases the specific surface area. At the same time, the hollow structure can be effectively utilized to improve the adsorption effect.

[0030] (2) The pure carbon tube aerogel prepared in this invention has no other substrate skeleton added, which greatly reduces the density of the product and has the characteristics of being lightweight and high-strength. This tough material has the advantage of repeated adsorption and recycling.

[0031] (3) The present invention can control the amount and concentration of the initial carbon nanotube raw material to prepare aerogel products of different sizes. The size of the adsorption material can be customized according to actual needs, which makes up for the shortcomings of the customization of traditional aerogel materials.

[0032] (4) The acidification process used in this invention can not only effectively remove the etching agent added in the stripping process, but also oxidize the carbon nanotubes, increasing oxygen-containing functional groups at the defect sites of the carbon nanotubes, which is more conducive to the cross-linking of carbon nanotube gel.

[0033] (5) The single-walled carbon nanotube aerogel obtained by the method of the present invention has a 55% higher specific surface area. The single-walled carbon nanotubes are freeze-dried after gelation to prepare a bulk aerogel product, which exhibits excellent methylene blue solution adsorption performance. Its removal efficiency reaches over 90%. Attached Figure Description

[0034] Figure 1 This is a schematic flowchart of a method for preparing a single-walled carbon nanotube aerogel according to the present invention.

[0035] Figure 2 This is a photograph of a single-walled carbon nanotube aerogel prepared in Example 1 of the present invention.

[0036] Figure 3 This is a scanning electron microscope image of a single-walled carbon nanotube aerogel prepared in Example 1 of the present invention.

[0037] Figure 4 This is a transmission electron microscope image of a single-walled carbon nanotube aerogel prepared in Example 1 of the present invention.

[0038] Figure 5 This is a time-adsorption curve of methylene blue at different concentrations for a single-walled carbon nanotube aerogel prepared in Example 1 of the present invention.

[0039] Figure 6 This is a histogram showing the removal rate of methylene blue at different concentrations by a single-walled carbon nanotube aerogel prepared in Example 1 of this invention.

[0040] Figure 7 This is a photograph of a single-walled carbon nanotube aerogel prepared in Example 2 of the present invention. Specific implementation methods

[0041] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0042] like Figure 1 As shown, this invention discloses a method for preparing single-walled carbon nanotube aerogels, which specifically includes the following steps:

[0043] S1) Single-walled carbon nanotubes are processed to obtain initially dispersed carbon nanotube powder, and then the carbon nanotube powder is subjected to carbon cap peeling treatment to obtain the peeled carbon nanotube product.

[0044] The specific process is as follows:

[0045] S1.1) Single-walled carbon nanotubes prepared by arc discharge method are mechanically sheared to obtain initially dispersed carbon nanotube powder with an average particle size of 30-150 μm.

[0046] S1.2) The carbon nanotube powder obtained in S1.1) is immersed in an etchant solution with a concentration of 0.1-5.0 mol / L at a mass ratio of carbon nanotube powder to etchant of 1:(0.5-3.0). After filtration and drying, the immersion material is placed in a reaction furnace with a heating rate of 2-15℃ / min, a treatment temperature of 600-1000℃, and a holding time of 0.5-4h. The entire process is carried out under an inert atmosphere to remove the carbon caps of the carbon nanotubes, and the removed carbon nanotube product is obtained.

[0047] S2) First, dilute concentrated hydrochloric acid and concentrated nitric acid in a molar ratio of (1.0–12.0):1 with water to prepare a mixed acid solution with a concentration of 0.5–8 mol / L. Then, add the carbon nanotube product after stripping to the prepared mixed acid solution to obtain a mixed solution with a solid content of 0.02–0.5 g / L. Then, reflux the mixed solution at a temperature of 60–120℃ for 5–12 h to complete the acidification treatment. Finally, filter and wash the acidified carbon nanotube product, and then prepare it to obtain a carbon nanotube slurry.

[0048] S3) The carbon nanotube slurry obtained in S2) is subjected to gel treatment, and the resulting gel product is freeze-dried to obtain single-walled carbon nanotube aerogel.

[0049] The specific process is as follows:

[0050] S3.1) First, add the complexing agent to the carbon nanotube slurry and mix thoroughly;

[0051] S3.2) At a temperature of 50–120°C for 10–48 h, gelation treatment is performed. The resulting gel product is then freeze-dried to obtain single-walled carbon nanotube aerogel.

[0052] The density of the single-walled carbon nanotube aerogel is 0.3–1.0 kg / m³. 3It has a porosity of over 80% and a specific surface area of ​​600–1300 m². 2 / g.

[0053] Preferably, the etching agent is at least one selected from zinc chloride, aluminum chloride, calcium chloride, calcium hydroxide, potassium hydroxide, sodium oxide, and sodium amide.

[0054] The reactor is a tubular furnace.

[0055] Preferably, the complexing agent is at least one of sodium citrate, sodium thiosulfate, sodium sulfite, sodium alginate, disodium diethylaminetetraacetate, sodium hexametaphosphate, and diethanolamine.

[0056] A single-walled carbon nanotube aerogel prepared by the above method is used in dye adsorption. Its removal efficiency for methylene blue reaches more than 96%, and the maximum adsorption capacity is 635 mg / g.

[0057] Example 1

[0058] A suitable amount of single-walled carbon nanotubes prepared by arc discharge method was weighed and mechanically sheared in a cutting machine to obtain initially dispersed carbon nanotube powder with a particle size of 50 μm. A suitable amount of potassium hydroxide was weighed as an etchant, and the carbon nanotube powder and etchant were mixed at a mass ratio of 1:2 to prepare an aqueous solution with a concentration of 2.0 mol / L. The solution was allowed to stand for 48 h to allow the carbon nanotubes to be fully wetted. After filtering and drying the wetted material, it was placed in a graphite boat and placed in a tube furnace under an inert argon atmosphere. The temperature was increased to 800℃ at a rate of 5℃ / min and held for 2 h for exfoliation. The material was then allowed to cool naturally. The exfoliated carbon nanotube product was removed from the tube furnace and added to a mixed acid solution prepared with hydrochloric acid and nitric acid, where the molar ratio of concentrated hydrochloric acid to concentrated nitric acid was 5:1 and the concentration of the mixed acid solution was 4 mol / L, forming a mixed solution with a carbon nanotube solid content of 0.2 g / L. The mixed solution was then refluxed at 90℃ for 10 h. The acidified product was filtered and washed to prepare an aqueous paste with a concentration of 0.8 g / L. This paste was then dispersed at high speed to obtain a carbon nanotube slurry with a particle size of 30 μm. 150 mL of this slurry was placed in a fixed container, and disodium diethylaminetetraacetate was added as a complexing agent and mixed thoroughly. The mixture was then gelled at 100 °C for 36 h. The resulting wet gel product was then freeze-dried to obtain a single-walled carbon nanotube aerogel.

[0059] Prepare methylene blue solutions of different concentrations, completely immerse the prepared single-walled carbon nanotube aerogels in the solutions, and take samples at different times to test and record the changes in methylene blue concentration.

[0060] The single-walled carbon nanotube aerogel was characterized. A photograph of the obtained product is shown below. Figure 2As shown, a complete cylindrical black product with a diameter of 3.5 cm and a height of 6.0 cm can be extracted. The product is loose and porous, lightweight, and has some unevenness on the surface. Its density was tested to be 0.5 kg / m³. 3 Specific surface area is 1008 m² 2 / g. Scanning electron microscope images of the product are shown below. Figure 3 As shown, the tightly packed carbon nanotube bundles appear randomly, with a very clean surface; no other obvious impurities are present besides the carbon nanotubes. This morphology ensures the purity of the aerogel sample, and the tight network structure also ensures that the aerogel has a certain strength. Transmission electron micrographs are shown below. Figure 4 As shown, after sample preparation and dispersion, the bundled carbon nanotubes showed several clustered strands. These clustered carbon nanotubes were straight and single-walled, with no impurities. The end of one protruding carbon nanotube was removed, leaving it open, which is a result of the stripping process. Figure 5 The adsorption curves of the aerogel product in this example for methylene blue solutions of different concentrations were recorded at different times. As time increased, the product was roughly saturated with methylene blue solutions of different concentrations after 1000 min. The maximum adsorption capacity was 635 mg / g when the concentration was 0.70 g / L, which showed excellent adsorption effect. Figure 6 The histograms of removal rates at different methylene blue concentrations show that the adsorption removal rate gradually decreases with increasing methylene blue concentration, indicating that saturation is more easily reached at higher concentrations. Within the test range of 0.1–0.7 g / L, the overall removal rate can reach over 90%, with the highest removal rate of 96.8% at a concentration of 0.1 g / L, demonstrating excellent adsorption and removal performance.

[0061] Comparative Example 1

[0062] To further illustrate the effect of the exfoliation process on single-walled carbon nanotubes in this invention, Comparative Example 1 was formed by not performing the exfoliation process on the carbon nanotubes, based on Example 1.

[0063] A suitable amount of single-walled carbon nanotubes prepared by arc discharge method was weighed and mechanically sheared in a cutting machine to obtain initially dispersed carbon nanotube powder with a particle size of 50 μm. This powder was added to a mixed acid solution prepared with hydrochloric acid and nitric acid, wherein the molar ratio of concentrated hydrochloric acid to concentrated nitric acid was 5:1, and the concentration of the mixed acid solution was 2 mol / L, forming a mixed solution with a carbon nanotube solid content of 0.2 g / L. The mixed solution was refluxed at 90℃ for 10 h. The acidified product was filtered and washed, and prepared into an aqueous paste with a concentration of 0.8 g / L. This paste was then dispersed at high speed to obtain a carbon nanotube slurry with a particle size of 30 μm. 150 mL of the slurry was placed in a fixed container, and disodium diethylaminetetraacetate was added as a complexing agent and mixed thoroughly. The mixture was then gelled at 100℃ for 36 h. The resulting wet gel product was lyophilized to obtain the aerogel product.

[0064] Prepare methylene blue solutions of different concentrations, completely immerse the prepared aerogel in the solutions, take samples at different times, and record the changes in methylene blue concentration.

[0065] Example 2

[0066] A suitable amount of single-walled carbon nanotubes prepared by arc discharge method was weighed and mechanically sheared in a cutting machine to obtain initially dispersed carbon nanotube powder with a particle size of 30 μm. A suitable amount of sodium amide was weighed as an etchant, and the carbon nanotube powder and etchant were mixed at a mass ratio of 1:2 to prepare an aqueous solution with a concentration of 2.0 mol / L. The solution was allowed to stand for 48 h to fully wet the carbon nanotubes. After filtering and drying the wetted material, it was placed in a graphite boat and placed in a tube furnace under an inert argon atmosphere. The temperature was increased to 700℃ at a rate of 5℃ / min and held for 2 h for exfoliation. The material was then allowed to cool naturally. The exfoliated carbon nanotube product was removed from the tube furnace and added to a mixed acid solution prepared by hydrochloric acid and nitric acid, wherein the molar ratio of concentrated hydrochloric acid to concentrated nitric acid was 5:1 and the concentration of the mixed acid solution was 2 mol / L, forming a mixed solution with a carbon nanotube solid content of 0.2 g / L. The mixed solution was refluxed at 90℃ for 10 h. The acidified product was filtered and washed to prepare an aqueous paste with a concentration of 1.2 g / L. This paste was then dispersed at high speed to obtain a carbon nanotube slurry with a particle size of 20 μm. 50 mL of this slurry was placed in a fixed container, and sodium alginate was added as a complexing agent and mixed thoroughly. The mixture was then gelled at 90°C for 30 h. The resulting wet gel product was then freeze-dried to obtain a single-walled carbon nanotube aerogel.

[0067] The above-mentioned single-walled carbon nanotube aerogel was characterized. A photograph of the obtained product is shown below. Figure 7 The image shows a flat, thin, black sheet-like product with a diameter of 3.5 cm and a height of 0.6 cm. The product is lightweight, high-strength, and not easily broken. Its density, as tested, is 0.6 kg / m³. 3Specific surface area is 980m² 2 / g.

[0068] Prepare methylene blue solutions of different concentrations, completely immerse the prepared single-walled carbon nanotube aerogels in the solutions, and take samples at different times to test and record the changes in methylene blue concentration.

[0069] Table 1. Physical properties and adsorption performance test results of the aerogels in the examples and comparative examples.

[0070]

[0071]

[0072] As can be seen from the results in the table above, Example 1, compared to Comparative Example 1, underwent a stripping process, which opened the carbon nanotube ports and increased the specific surface area by 55%. Simultaneously, the adsorption performance, such as the maximum adsorption capacity and removal rate, was also significantly improved. By adjusting the content of the aqueous paste containing carbon nanotubes during the gelation process, aerogel products of different sizes can be prepared. In Example 2, by reducing the content of carbon nanotubes before gelation, aerogel block products with a uniform diameter and a height one-tenth that of Example 1 were prepared, which also exhibited good adsorption performance.

[0073] Example 3

[0074] A suitable amount of single-walled carbon nanotubes prepared by arc discharge method was weighed and mechanically sheared in a cutting machine to obtain initially dispersed carbon nanotube powder with a particle size of 80 μm. A suitable amount of zinc chloride was weighed as an etchant, and the carbon nanotube powder and etchant were mixed at a mass ratio of 1:2.5 to prepare an aqueous solution with a concentration of 4.0 mol / L. The solution was allowed to stand for 48 h to allow the carbon nanotubes to be fully wetted. After filtering and drying the wetted material, it was placed in a graphite boat and placed in a tube furnace under an inert argon atmosphere. The temperature was increased to 900℃ at a rate of 5℃ / min and held for 3 h for exfoliation. The material was then allowed to cool naturally. The exfoliated carbon nanotube product was removed from the tube furnace and added to a mixed acid solution prepared by hydrochloric acid and nitric acid, wherein the molar ratio of concentrated hydrochloric acid to concentrated nitric acid was 5:1 and the concentration of the mixed acid solution was 3 mol / L, forming a mixed solution with a carbon nanotube solid content of 0.2 g / L. The mixed solution was refluxed at 90℃ for 10 h. The acidified product was filtered and washed to prepare an aqueous paste with a concentration of 1.2 g / L. This paste was then dispersed at high speed to obtain a carbon nanotube slurry with a particle size of 30 μm. 150 mL of this slurry was placed in a fixed container, and sodium citrate was added as a complexing agent and mixed thoroughly. The mixture was then gelled at 90°C for 30 h. The resulting wet gel product was then freeze-dried to obtain a single-walled carbon nanotube aerogel.

[0075] Example 4

[0076] A suitable amount of single-walled carbon nanotubes prepared by arc discharge method was weighed and mechanically sheared in a cutting machine to obtain initially dispersed carbon nanotube powder with a particle size of 70 μm. A suitable amount of aluminum chloride was weighed as an etchant, and the carbon nanotube powder and etchant were mixed at a mass ratio of 1:1.5 to prepare an aqueous solution with a concentration of 4.0 mol / L. The solution was allowed to stand for 48 h to allow the carbon nanotubes to be fully wetted. After filtering and drying the wetted material, it was placed in a graphite boat and placed in a tube furnace under an inert argon atmosphere. The temperature was increased to 800℃ at a rate of 5℃ / min and held for 2 h for exfoliation. The material was then allowed to cool naturally. The exfoliated carbon nanotube product was removed from the tube furnace and added to a mixed acid solution prepared with hydrochloric acid and nitric acid, where the molar ratio of concentrated hydrochloric acid to concentrated nitric acid was 5:1 and the concentration of the mixed acid solution was 3 mol / L, forming a mixed solution with a carbon nanotube solid content of 0.2 g / L. The mixed solution was then refluxed at 110℃ for 10 h. The acidified product was filtered and washed to prepare an aqueous paste with a concentration of 1.5 g / L. This paste was then dispersed at high speed to obtain a carbon nanotube slurry with a particle size of 20 μm. 100 mL of this slurry was placed in a fixed container, and sodium hexametaphosphate was added as a complexing agent and mixed thoroughly. The mixture was then gelled at 110 °C for 40 h. The resulting wet gel product was then freeze-dried to obtain a single-walled carbon nanotube aerogel.

[0077] Example 5

[0078] A suitable amount of single-walled carbon nanotubes prepared by arc discharge method was weighed and mechanically sheared in a cutting machine to obtain initially dispersed carbon nanotube powder with a particle size of 120 μm. A suitable amount of calcium hydroxide was weighed as an etchant, and the carbon nanotube powder and etchant were mixed at a mass ratio of 1:2.5 to prepare an aqueous solution with a concentration of 4.0 mol / L. The solution was allowed to stand for 48 h to allow the carbon nanotubes to be fully wetted. After filtering and drying the wetted material, it was placed in a graphite boat and placed in a tube furnace under an inert argon atmosphere. The temperature was increased to 950℃ at a rate of 10℃ / min and held for 3 h for exfoliation. The material was then allowed to cool naturally. The exfoliated carbon nanotube product was removed from the tube furnace and added to a mixed acid solution prepared with hydrochloric acid and nitric acid, where the molar ratio of concentrated hydrochloric acid to concentrated nitric acid was 7:1 and the concentration of the mixed acid solution was 4 mol / L, forming a mixed solution with a carbon nanotube solid content of 0.2 g / L. The mixed solution was then refluxed at 100℃ for 10 h. The acidified product was filtered and washed to prepare an aqueous paste with a concentration of 1.5 g / L. This paste was then dispersed at high speed to obtain a carbon nanotube slurry with a particle size of 30 μm. 150 mL of this slurry was placed in a fixed container, and sodium thiosulfate was added as a complexing agent and mixed thoroughly. The mixture was then gelled at 100 °C for 45 h. The resulting wet gel product was then freeze-dried to obtain a single-walled carbon nanotube aerogel.

[0079] The preparation method of single-walled carbon nanotube aerogel and its application provided in the embodiments of this application have been described in detail above. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​this application; at the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​this application. Therefore, the content of this specification should not be construed as a limitation of this application.

[0080] Certain terms are used in the specification and claims to refer to specific components. Those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The terms "comprising" and "including" used throughout the specification and claims are open-ended and should be interpreted as "comprising / including but not limited to". "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error. The following descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of illustrating the general principles of this application and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0081] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0082] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0083] The foregoing description illustrates and describes several preferred embodiments of this application. However, as previously stated, it should be understood that this application is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the application concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this application should be within the protection scope of the appended claims.

Claims

1. A method for preparing a single-walled carbon nanotube aerogel, characterized by, The preparation method specifically comprises the following steps: S1) treating single-walled carbon nanotubes to obtain initially dispersed carbon nanotube powder, and then performing carbon cap peeling treatment on the carbon nanotube powder to obtain a peeling carbon nanotube product; The specific steps are: S1.1) performing mechanical shearing on single-walled carbon nanotubes prepared by arc discharge to obtain initially dispersed carbon nanotube powder; S1.2) immersing the carbon nanotube powder obtained in S1.1) into an etchant solution of a certain concentration at a certain proportion, then drying the immersion product by suction filtration, and then placing it into a reaction furnace to perform carbon cap peeling treatment, thereby obtaining a peeling carbon nanotube product; The average particle size of the initially dispersed carbon nanotube powder in S1.1) is 30-150 μm; The concentration of the etchant solution in S1.2) is 0.1-5.0 mol / L, and the mass ratio of the carbon nanotube powder to the etchant is 1:(0.5-3.0); The peeling treatment process is as follows: the heating rate is 2-15 ℃ / min, the treatment temperature is 600-1000 ℃, and the holding time is 0.5-4 h, and inert atmosphere protection is adopted throughout the process; The etchant is at least one of zinc chloride, aluminum chloride, calcium chloride, calcium hydroxide, potassium hydroxide, sodium oxide, and sodium amide; S2) taking out the peeling carbon nanotube product in S1), adding it into a mixed acid solution to perform acidification treatment, then suction filtering and washing the acidification-treated carbon nanotube product, and then adjusting to obtain a carbon nanotube slurry; S3) performing gel treatment on the carbon nanotube slurry obtained in S2), and then taking out the obtained gel product to perform freeze-drying, thereby obtaining single-walled carbon nanotube aerogel; The specific steps are: S3.1) first adding a complexing agent into the carbon nanotube slurry and mixing uniformly; S3.2) performing gel treatment at a temperature of 50-120 ℃ for 10-48 h, and then taking out the obtained gel product to perform freeze-drying, thereby obtaining single-walled carbon nanotube aerogel.

2. The preparation method according to claim 1, characterized in that: The reaction furnace is a tubular furnace.

3. The preparation method according to claim 1, characterized in that, The specific steps of S2) are: S2.1) mixing the peeling carbon nanotube product with a mixed acid solution to prepare a mixed solution with a carbon nanotube product solid content of 0.02-0.5 g / L, then performing condensation reflux treatment on the mixed solution at a temperature of 60-120 ℃ for 5-12 h to obtain a carbon nanotube slurry; S2.2) then performing high-speed dispersion on the carbon nanotube slurry obtained in S2.1) to obtain a carbon nanotube slurry with an average particle size of 10-50 μm and a concentration of 0.2-2 g / L.

4. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The complexing agent is at least one of sodium citrate, sodium thiosulfate, sodium alginate, diethylenetriamine pentaacetic acid disodium, sodium hexametaphosphate, and diethanolamine.

5. A single-walled carbon nanotube aerogel, characterized by, The single-walled carbon nanotube aerogel is prepared by the method of any one of claims 1-4, and has a density of 0.3-1.0 kg / m 3 , a porosity of 80% or more, and a specific surface area of 600-1300 m 2 / g.

6. Application of single-walled carbon nanotube aerogel prepared by the preparation method according to any one of claims 1-4 in dye adsorption, which has a methylene blue removal efficiency of 90% or more and a maximum adsorption capacity of 635 mg / g.

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