Magnetic carbon aerogel as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of carbon aerogel, and particularly relates to magnetic carbon aerogel as well as a preparation method and application thereof. The preparation method comprises the following steps: (1) dispersing magnetic nanoparticles, and uniformly mixing the dispersed magnetic nanoparticles with a solvent to obtain a dispersion liquid; dissolving an organic monomer, a cross-linking agent and a catalyst, and uniformly mixing with a solvent to obtain a precursor solution; (2) uniformly mixing the dispersion liquid with the precursor solution, and carrying out gelation reaction to obtain gel of magnetic carbon aerogel; and (3) drying the gel of the magnetic carbon aerogel to obtain the magnetic carbon aerogel. The preparation method is simple in process and low in cost, and the prepared magnetic carbon aerogel has high specific surface area, rich pore structure and good magnetic performance, and has wide application prospects in the fields of environmental governance and energy storage.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon aerogels, and in particular relates to a magnetic carbon aerogel and a preparation method and application thereof. Background Art

[0002] With the acceleration of industrialization and the increasing severity of environmental pollution, the demand for high-efficiency adsorption materials continues to increase. Carbon aerogel, a material with high specific surface area, low density, good conductivity and thermal stability, is widely used in electrochemical energy storage, catalyst carriers, adsorption materials and other fields. However, the preparation of traditional carbon aerogels mostly relies on fossil fuels, which not only increases costs but also is not conducive to environmental protection. Therefore, finding sustainable and low-cost magnetic nanoparticles to prepare carbon aerogels has become a research focus.

[0003] CN109289814A discloses a magnetic carbon aerogel for adsorbing antibiotics in wastewater and a preparation method thereof. The magnetic carbon aerogel is composed of carbon aerogel and magnetic particles uniformly distributed in the pores of the carbon aerogel. The invention synthesizes magnetic carbon aerogel with magnetic response by adding an appropriate amount of magnetic nanoparticle dispersion into the reaction precursor of carbon aerogel. The particles are evenly distributed in the carbon aerogel structure network. However, this method is not environmentally friendly and the wastewater generated is likely to cause environmental pollution.

[0004] CN17619344A discloses a magnetic carbon aerogel, its preparation method, and application. The aerogel comprises cross-linking ferroferric oxide nanoparticles with sodium carboxymethyl cellulose using citric acid monohydrate, followed by high-temperature heat treatment. However, the aerogel cannot be applied in the field of new energy batteries.

[0005] Therefore, the prior art still requires a method for preparing carbon aerogel with simple preparation process and reliable product quality. Summary of the Invention

[0006] The present invention aims to address the shortcomings of existing carbon aerogel preparation methods by obtaining a carbon aerogel with excellent physical and chemical properties through carbonization, thereby expanding the application field of carbon aerogels. The detailed technical solution of the present invention is described below.

[0007] The present invention provides a method for preparing a magnetic carbon aerogel, comprising the following steps: (1) After dispersing the magnetic nanoparticles, the mixture is uniformly mixed with a solvent to obtain a dispersion; the organic monomer, cross-linking agent, and catalyst are dissolved and uniformly mixed to obtain a precursor solution; (2) uniformly mixing the dispersion and the precursor solution, performing a gelation reaction, and obtaining a gel; (3) The gel is dried to obtain magnetic carbon aerogel.

[0008] Preferably, the gelation reaction includes a high-temperature gelation reaction, wherein the high temperature is 60° C.-85° C., specifically, the reaction is carried out at 60° C.-85° C. for 12 h to 24 h.

[0009] Preferably, the gelation reaction further comprises a low-temperature gelation reaction. In step (2), the low-temperature gelation reaction is first performed and then the high-temperature gelation reaction is performed. The low temperature is 25°C-35°C. Specifically, the low-temperature gelation reaction is performed at 25°C-35°C for 12h-24h.

[0010] Preferably, after the dispersion and the precursor solution are evenly mixed, carbon nanotubes are added, stirred evenly, and allowed to stand for degassing before a gelation reaction is carried out.

[0011] Preferably, in step (1), the magnetic nanoparticles include any one of ferroferric oxide, cobalt ferrite and nickel ferrite.

[0012] Preferably, in step (1), the organic monomer includes at least one of resorcinol, phenol or furfural; the cross-linking agent includes at least one of formaldehyde, glutaraldehyde and glyoxal; and the catalyst includes at least one of sodium carbonate, ammonia water and sodium hydroxide.

[0013] Preferably, the drying treatment in step (3) includes vacuum drying, freeze drying or carbon dioxide supercritical drying.

[0014] Preferably, the solvent includes at least one of ethanol and dimethylformamide.

[0015] The present invention also protects a magnetic carbon aerogel prepared by the above-mentioned preparation method.

[0016] The present invention also protects the application of magnetic carbon aerogel in electrochemical energy storage and adsorption materials.

[0017] The first inventive point of the present invention is the innovative composite process of magnetic nanoparticles and carbon aerogels, which solves the technical problem that magnetic particles are easy to aggregate and difficult to load evenly, and improves the magnetic responsiveness and structural stability of the material. 、 The magnetic particles are pre-dispersed in a solvent and then mixed with a precursor solution (organic monomer + cross-linker + catalyst) to ensure uniform distribution of the magnetic particles in the three-dimensional network of the carbon aerogel and avoid agglomeration.

[0018] The second inventive point of the present invention is the optimization and controllability of the gelation process. The step-by-step gelation process is adopted to significantly improve the performance of the material. In application, the specific surface area, porosity, and saturation magnetization intensity parameter values ​​are better.

[0019] The third inventive point of this invention is the clear expansion of its application areas. Through material design, multifunctional integration of "adsorption-magnetic separation" or "energy storage-magnetic control" can be achieved. For example, electrochemical energy storage and adsorption materials: Utilizing the high specific surface area, porous structure, and magnetic recovery properties of magnetic carbon aerogels, applications in electrochemical energy storage or adsorption materials are proposed.

[0020] Therefore, the beneficial effects of the present invention are: (1) The process of the present invention is simple and low-cost. The prepared magnetic carbon aerogel has a high specific surface area, rich pore structure and good magnetic properties, and has broad application prospects in the fields of environmental governance and energy storage.

[0021] (2) The present invention can efficiently adsorb pollutants in wastewater and achieve rapid separation and recovery under the action of an external magnetic field; in energy storage, it exhibits excellent electrochemical properties as an electrode material for supercapacitors. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a graph showing the saturation magnetization and specific surface area of ​​the magnetic carbon aerogel electrode material of the embodiment. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings: Example Example 1

[0024] 1. Add 0.4g The nanoparticles and 0.1 g of hyaluronic acid were co-dispersed in 50 mL of PBS buffer (pH = 7.4) and ultrasonicated for 60 min to obtain a uniform dispersion.

[0025] 2. Dissolve 6 g of dopamine, 10 mL of glutaraldehyde, and 0.8 mL of triethylamine in 30 mL of ethanol / water (1:1) and stir under nitrogen to obtain a precursor solution.

[0026] 3. Mix the magnetic nanoparticle dispersion with the carbon aerogel precursor solution and stir for 1 h.

[0027] 4. The mixed solution was subjected to gelation reaction at 60℃ for 24h to form a biomimetic viscoelastic gel.

[0028] 5. Supercritical fluidization of biomimetic viscoelastic gel Magnetic carbon aerogel can be obtained after drying (40℃, 7.5MPa).

[0029] After testing, the magnetic carbon aerogel has a specific surface area of ​​760m² / g, a porosity of 88% (pore size 50-300μm), and a saturation magnetization intensity of 18emu / g.

[0030] Example 2 1. Disperse 0.5 g of ferroferric oxide nanoparticles in 50 mL of ethanol and ultrasonicate for 30 min to obtain a uniform dispersion.

[0031] 2. Dissolve 10 g of resorcinol, 15 mL of formaldehyde, and 1 mL of sodium carbonate in 50 mL of water and stir well to obtain a precursor solution.

[0032] 3. Mix the magnetic nanoparticle dispersion with the carbon aerogel precursor solution and stir for 1 h.

[0033] 4. The mixed solution was subjected to gelation reaction at 80°C for 24 hours to obtain a magnetic carbon aerogel gel.

[0034] 5. The magnetic carbon aerogel was vacuum dried at 80°C for 24 h to obtain magnetic carbon aerogel.

[0035] After testing, the magnetic carbon aerogel has a specific surface area of ​​800m² / g, a porosity of 80%, and a saturation magnetization of 20emu / g.

[0036] Example 3 1. Disperse 0.8 g of nickel ferrite nanoparticles in 50 mL of water and ultrasonicate for 30 min to obtain a uniform dispersion.

[0037] 2. Dissolve 12 g of furfural, 18 mL of glyoxal, and 1.5 mL of sodium hydroxide in 50 mL of N,N-dimethylformamide and stir well to obtain a precursor solution.

[0038] 3. Mix the magnetic nanoparticle dispersion with the carbon aerogel precursor solution and stir for 1 h.

[0039] 4. The mixed solution was subjected to gelation reaction at 85°C for 24 hours to obtain a magnetic carbon aerogel gel.

[0040] 5. The magnetic carbon aerogel was vacuum dried at 90°C for 24 h to obtain the magnetic carbon aerogel.

[0041] After testing, the magnetic carbon aerogel has a specific surface area of ​​900m² / g, a porosity of 82%, and a saturation magnetization of 25emu / g.

[0042] Example 4 1. Add 0.6g The core-shell nanoparticles (carbon layer thickness 2 nm) were dispersed in 40 mL of ethylene glycol and sonicated for 45 min to obtain a stable dispersion.

[0043] 2. Dissolve 10 g of aniline, 15 mL of formaldehyde, and 0.5 g of sodium polystyrene sulfonate (PSS) in 50 mL of 1 M HCl solution and stir on ice for 30 min to obtain a precursor solution.

[0044] 3. Mix the magnetic dispersion with the precursor solution, add 0.2g of carbon nanotubes, stir magnetically for 2h, and then let it stand for degassing.

[0045] 4. Gel the mixed solution: first stage: react at 25℃ for 12h; second stage: react at 60℃ for 12h.

[0046] 5. After freeze drying (-50℃, 24h), annealing at 700℃ in argon for 1h to obtain magnetic carbon aerogel.

[0047] After testing, the magnetic carbon aerogel has a specific surface area of ​​950m² / g, a porosity of 84%, and a saturation magnetization of 28emu / g.

[0048] Example 5 1. Disperse 1.0 g of cobalt ferrite nanoparticles in 50 mL of N,N-dimethylformamide and ultrasonicate for 30 min to obtain a uniform dispersion.

[0049] 2. Dissolve 15 g of phenol, 20 mL of glutaraldehyde, and 2 mL of ammonia water in 50 mL of ethanol and stir well to obtain a precursor solution.

[0050] 3. Mix the magnetic nanoparticle dispersion with the carbon aerogel precursor solution and stir for 1 h.

[0051] 4. Gelation of the mixed solution: first stage: reaction at 35°C for 12 h; second stage: reaction at 85°C for 12 h.

[0052] 5. The magnetic carbon aerogel was vacuum dried at 100°C for 24 h to obtain the magnetic carbon aerogel.

[0053] After testing, the magnetic carbon aerogel has a specific surface area of ​​1000m² / g, a porosity of 85%, and a saturation magnetization of 30emu / g.

[0054] In the above embodiment, the specific surface area test method is the gas adsorption method, BET method, GB / T 19587-2017 "Determination of specific surface area of ​​solid substances by gas adsorption BET method"; the porosity test method is the apparent density method, ASTM D6226-21 "Determination of open porosity of porous materials by helium pycnometer"; and the saturation magnetization test method is the vibrating sample magnetometer, VSM method, ASTM A342-18 "Magnetic permeability of weakly magnetic materials".

[0055] Application Examples

[0056] The carbon aerogel composite material prepared above was used as the electrode material of the supercapacitor, and the test results are shown in Table 1.

[0057] Table 1

[0058] Figure 1 2 is a graph showing the saturation magnetization and specific surface area of ​​the magnetic carbon aerogel electrode material in the embodiment. As can be seen from the graph, the saturation magnetization of the magnetic carbon aerogel electrode material increases with increasing specific surface area, and has a higher saturation magnetization.

[0059] In summary, the present invention utilizes the high specific surface area, porous structure and magnetic recovery properties of magnetic carbon aerogel, and can exhibit excellent electrochemical performance in electrochemical energy storage or adsorption materials, with high specific capacitance and good cycle stability. It is suitable for the preparation of high-performance supercapacitors and can also efficiently adsorb pollutants in wastewater and achieve rapid separation and recovery under the action of an external magnetic field.

[0060] Based on the disclosure and teachings of the above description, those skilled in the art may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and any modifications and variations of the invention should also fall within the scope of protection of the claims of the present invention. In addition, although certain specific terms are used in this description, these terms are for convenience of description only and do not constitute any limitation to the present invention.

Claims

1. A method for preparing magnetic carbon aerogel, characterized in that: The following steps are involved: (1) After dispersing the magnetic nanoparticles, the mixture is uniformly mixed with a solvent to obtain a dispersion; the organic monomer, cross-linking agent, and catalyst are dissolved and uniformly mixed to obtain a precursor solution; (2) uniformly mixing the dispersion and the precursor solution, performing a gelation reaction, and obtaining a gel; (3) The gel is dried to obtain magnetic carbon aerogel.

2. The preparation method according to claim 1, characterized in that The gelation reaction includes a high-temperature gelation reaction, wherein the high temperature is 60° C.-85° C., specifically, the reaction is carried out at 60° C.-85° C. for 12 h-24 h.

3. The preparation method according to claim 2, characterized in that The gelation reaction also includes a low-temperature gelation reaction. In step (2), a low-temperature gelation reaction is first performed, and then a high-temperature gelation reaction is performed. The low temperature is 25°C-35°C. The low-temperature gelation reaction is specifically performed at 25°C-35°C for 12h-24h.

4. The preparation method according to claim 3, characterized in that After the dispersion and the precursor solution are evenly mixed, carbon nanotubes are added, stirred evenly, and allowed to stand for degassing, and then a gelation reaction is carried out.

5. The preparation method according to claim 2 or 3, characterized in that In step (1), the magnetic nanoparticles include any one of ferroferric oxide, cobalt ferrite and nickel ferrite.

6. The preparation method according to claim 4, characterized in that In step (1), the organic monomer includes at least one of resorcinol, phenol or furfural; the cross-linking agent includes at least one of formaldehyde, glutaraldehyde and glyoxal; and the catalyst includes at least one of sodium carbonate, ammonia water and sodium hydroxide.

7. The preparation method according to claim 1, characterized in that The drying treatment in step (3) includes vacuum drying, freeze drying or supercritical carbon dioxide drying.

8. The preparation method according to claim 1, characterized in that The solvent includes at least one of ethanol and dimethylformamide.

9. A magnetic carbon aerogel, characterized in that It is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the magnetic carbon aerogel according to claim 9 in electrochemical energy storage and adsorption materials.

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