Nitrogen-doped spherical activated carbon as well as preparation method and application thereof

Abstract

The invention discloses nitrogen-doped spherical activated carbon and a preparation method and application thereof.The preparation method comprises the steps that raw materials containing epoxy resin, a curing agent and an organic solvent are mixed to obtain a mixed solution, the mixed solution is dropped into a hot oil column, and thermosetting epoxy resin balls are obtained through crosslinking, curing, balling and drying; and further performing high-temperature carbonization to obtain the nitrogen-doped spherical activated carbon. The preparation method disclosed by the invention is simple and can be continuously operated. The obtained spherical activated carbon is uniform in size.

Description

Technical Field

[0001] The present application relates to a nitrogen-doped spherical activated carbon and a preparation method and application thereof, belonging to the field of activated carbon materials. Background Art

[0002] Spherical activated carbon is a new type of high-performance activated carbon with a smooth surface. It has unique properties such as high purity, low ash powder, high strength, high wear resistance, high fluidity and narrow particle size distribution. Therefore, it has broad application prospects in the fields of solvent recovery, gas purification, water treatment, etc. For example, spherical activated carbon has been used in the fields of adsorption materials for clean room filters in the semiconductor industry, gas treatment of electronic devices, etc. In addition, due to its good physiological solubility, spherical activated carbon also has important applications in medical and health fields such as blood purification.

[0003] Spherical activated carbon can be divided into three types according to raw materials: asphalt-based spherical activated carbon, coal-based spherical activated carbon and polymer-based spherical activated carbon. Among them, polymer resin has the advantages of controllable raw material structure and low impurity content, especially thermosetting resins such as epoxy resin can be directly carbonized, which greatly simplifies the operation process and is an ideal raw material for preparing spherical activated carbon.

[0004] Compared with carbon atoms, nitrogen atoms have a slightly smaller atomic radius and a larger electronegativity (the electronegativity of N is 3.04, and the electronegativity of C is 2.55). Incorporating nitrogen into the structure of carbon materials will change the atomic and electronic structure of the matrix, increase its conductivity, and form a delocalized conjugated system of sp2 hybridized C, which will lead to the reactivity, mechanical and other macroscopic properties of the material, and significantly change its adsorption and catalytic properties.

[0005] At present, the main method of nitrogen doping is post-doping, which is to infiltrate nitrogen atoms through post-treatment such as oxidation, pyrolysis, and substitution of carbon materials (graphene, carbon nanotubes, carbon black, etc.). Because the graphite layer of these carbon materials has already been formed, N atoms cannot enter, so the N content of NC catalysts prepared by this method is generally not high and the catalytic activity is slightly lacking. In particular, there are relatively few studies on nitrogen doping of spherical activated carbon, and the preparation process of nitrogen-doped spherical activated carbon is relatively complicated. Summary of the invention

[0006] According to one aspect of the present application, a method for preparing nitrogen-doped spherical activated carbon is provided, wherein raw materials containing epoxy resin, a curing agent, and an organic solvent are mixed to obtain a mixed liquid, and the mixed liquid is dripped into a hot oil column, and subjected to cross-linking, curing, balling, and drying to obtain thermosetting epoxy resin balls; further subjected to high-temperature carbonization to obtain the nitrogen-doped spherical activated carbon, which solves the problem in the prior art that the N content of the NC catalyst is not high and the catalytic activity is slightly insufficient.

[0007] This application adopts the following technical solutions:

[0008] A method for preparing nitrogen-doped spherical activated carbon comprises the following steps:

[0009] S1, dripping a mixed liquid containing epoxy resin, curing agent and organic solvent into a hot oil column, allowing the mixed liquid droplets to solidify into balls in the hot oil column, and then taking out and drying to obtain thermosetting epoxy resin balls;

[0010] S2. Placing the thermosetting epoxy resin balls obtained in step S1 in an inert gas atmosphere for carbonization to obtain the nitrogen-doped spherical activated carbon.

[0011] Optionally, the inert gas is selected from at least one of nitrogen, argon and helium.

[0012] Optionally, the mixed liquid droplets are cross-linked, solidified, spheronized and dried in the oil column.

[0013] Optionally, in step S1, the epoxy resin is selected from at least one of glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, linear aliphatic epoxy resin, and alicyclic epoxy resin.

[0014] Optionally, in step S1, the curing agent is selected from at least one of diethylenetriamine, triethylenetetramine, triethylamine, imidazole, polyetheramine, m-phenylenediamine, hexahydropyridine, and melamine.

[0015] Optionally, in step S1, the weight ratio of the epoxy resin, the curing agent and the organic solvent is 1:(0.1-1):(0.1-10).

[0016] Optionally, the weight ratio of the curing agent to the epoxy resin is selected from any value of 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, or any range value therebetween.

[0017] Optionally, the weight ratio of the epoxy resin to the organic solvent is selected from any value of 0.1:1, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or any range therebetween.

[0018] Optionally, in step S1, the organic solvent is selected from at least one of ethanol, acetone, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran, and 1,4-dioxane.

[0019] Optionally, in step S1, the drying conditions include: a drying temperature of 90 to 180°C, and a drying time of 1 to 24 hours.

[0020] Optionally, in step S2, the oil in the hot oil column is selected from at least one of kerosene, vegetable oil, white oil, transformer oil, and liquid paraffin;

[0021] The temperature of the hot oil column is 80-180°C.

[0022] Optionally, in step S2, the carbonization conditions include: the carbonization temperature is 600-1200° C., and the carbonization time is 1-12 hours.

[0023] According to another aspect of the present application, a preparation method as described above is provided to prepare nitrogen-doped spherical activated carbon, wherein the particle size of the nitrogen-doped spherical activated carbon is 0.4 to 1.5 mm.

[0024] Optionally, the doping amount of nitrogen element in the nitrogen-doped spherical activated carbon is 1 to 10 wt %.

[0025] Optionally, the doping amount of nitrogen element in the nitrogen-doped spherical activated carbon is selected from any value of 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, or any range value between the two.

[0026] According to another aspect of the present application, there is also provided an application of the above-mentioned nitrogen-doped spherical activated carbon in gas purification, water purification, blood purification, and catalyst carrier.

[0027] The beneficial effects of this application include:

[0028] The method for preparing nitrogen-doped spherical activated carbon provided in the present application is simple and can be operated continuously. The spherical activated carbon obtained by the method has uniform size and can be directly prepared without adding an external nitrogen source, and the nitrogen doping amount is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a physical photo of the spherical activated carbon obtained in Example 1. DETAILED DESCRIPTION

[0030] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0031] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0032] Example 1

[0033] S1: dissolving 10 g of glycidyl ether epoxy resin (model E44) and 5 g of diethylenetriamine in 20 g of ethanol to obtain a uniform mixed solution;

[0034] S2: dropping the above solution into a hot oil column of 100°C white oil, so that the resin solution shrinks into a ball due to interfacial tension and solidifies into a ball during the slow falling process;

[0035] S3: Collect the resin balls at the bottom of the oil column, cool them to room temperature, wash them, and dry them at 120°C to obtain dry resin balls;

[0036] S4: Place the resin dry ball in a nitrogen atmosphere, raise the temperature to 850°C, and keep the temperature constant for 4 hours to obtain nitrogen-doped spherical activated carbon.

[0037] Figure 1 This is a physical picture of the spherical activated carbon obtained in Example 1, with an average particle size of 0.6 mm. It can be seen from the figure that the spherical activated carbon obtained has a uniform size. The mass content of nitrogen in the spherical activated carbon obtained in Example 1 is 4.7%.

[0038] Embodiments 2 to 5

[0039] The method is basically the same as Example 1, except that the white oil in S1 is replaced by kerosene, vegetable oil, transformer oil, and liquid paraffin in sequence, and the rest is exactly the same as Example 1.

[0040] The average particle sizes of the nitrogen-doped spherical activated carbons obtained in Examples 2 to 5 are 0.58 mm, 0.65 mm, 0.62 mm and 0.6 mm, respectively; similar to Example 1, the spherical activated carbons obtained are uniform in size.

[0041] The mass contents of nitrogen in the spherical activated carbons obtained in Examples 2 to 5 were 4.7%, 4.6%, 4.65% and 4.71%, respectively.

[0042] Example 6

[0043] It is basically the same as Example 1, except that the curing dosage in S1 is increased to 10 g, and the rest is exactly the same as Example 1.

[0044] The average particle size of the nitrogen-doped spherical activated carbon obtained in Example 6 was 1.05 mm, and similar to Example 1, the obtained spherical activated carbon had a uniform size. The mass content of nitrogen was 8.3%.

[0045] Example 7

[0046] The method is basically the same as Example 1, except that the amounts of epoxy resin and diethylenetriamine in S1 are adjusted to 15 g and 7.5 g, respectively. The rest is exactly the same as Example 1.

[0047] The average particle size of the nitrogen-doped spherical activated carbon obtained in Example 7 was 0.95 mm, and similar to Example 1, the spherical activated carbon obtained had a uniform size. The mass content of nitrogen was 4.8%.

[0048] Embodiments 8 to 14

[0049] The method is basically the same as Example 1, except that the diethylenetriamine in S1 is replaced by triethylenetetramine, triethylamine, imidazole, polyetheramine, metaphenylenediamine, hexahydropyridine and melamine in sequence, and the rest is exactly the same as Example 1.

[0050] The average particle sizes of the spherical activated carbons obtained in Examples 8 to 14 are 0.65 mm, 0.41 mm, 0.52 mm, 0.67 mm, 0.73 mm, 0.71 mm and 0.84 mm, respectively, and the mass contents of nitrogen are 5.6%, 2.3%, 3.4%, 6.7%, 4.3%, 3.1% and 8.5%, respectively.

[0051] Embodiments 15 to 19

[0052] The process is basically the same as Example 1, except that the ethanol in S1 is replaced by acetone, DMF, DMSO, tetrahydrofuran and 1,4-dioxane in sequence, and the rest is exactly the same as Example 1.

[0053] The average particle sizes of the spherical activated carbons obtained in Examples 15 to 19 are 0.44 mm, 0.68 mm, 0.66 mm, 0.49 mm and 0.71 mm, respectively, and the mass contents of nitrogen are 4.5%, 5.2%, 4.8%, 4.7% and 4.6%, respectively.

[0054] Embodiment 20

[0055] It is basically the same as Example 1, except that the amount of ethanol in S1 is replaced with 1 g, and the rest is exactly the same as Example 1.

[0056] The average particle size of the spherical activated carbon obtained in Example 20 is 1.2 mm, and the mass content of nitrogen is 4.75%.

[0057] Embodiment 21

[0058] It is basically the same as Example 1, the only difference is that the oil column temperature in S2 is replaced with 80°C, and the rest is exactly the same as Example 1.

[0059] The average particle size of the spherical activated carbon obtained in Example 21 is 0.48 mm, and the mass content of nitrogen is 3.43%.

[0060] Embodiment 22

[0061] It is basically the same as Example 1, except that the carbonization temperature in S3 is replaced with 1200° C., and the rest is exactly the same as Example 1.

[0062] The average particle size of the spherical activated carbon obtained in Example 22 is 0.56 mm, and the mass content of nitrogen is 1.43%.

[0063] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing nitrogen-doped spherical activated carbon, characterized in that: The steps include: S1, dripping a mixed liquid containing epoxy resin, curing agent and organic solvent into a hot oil column, allowing the mixed liquid droplets to solidify into balls in the hot oil column, and then taking out and drying to obtain thermosetting epoxy resin balls; S2. Placing the thermosetting epoxy resin balls obtained in step S1 in an inert gas atmosphere for carbonization to obtain the nitrogen-doped spherical activated carbon.

2. The preparation method according to claim 1, characterized in that: In step S1, the epoxy resin is selected from at least one of glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, linear aliphatic epoxy resin, and alicyclic epoxy resin.

3. The preparation method according to claim 1, characterized in that: In step S1, the curing agent is selected from at least one of diethylenetriamine, triethylenetetramine, triethylamine, imidazole, polyetheramine, m-phenylenediamine, hexahydropyridine, and melamine.

4. The preparation method according to claim 1, characterized in that: In step S1, the weight ratio of the epoxy resin, the curing agent and the organic solvent is 1:(0.1-1):(0.1-10).

5. The preparation method according to claim 1, characterized in that: In step S1, the organic solvent is selected from at least one of ethanol, acetone, DMF, DMSO, tetrahydrofuran, and 1,4-dioxane.

6. The preparation method according to claim 1, characterized in that: In step S1, the drying conditions include: a drying temperature of 90 to 180°C and a drying time of 1 to 24 hours.

7. The preparation method according to claim 1, characterized in that: In step S2, the oil in the hot oil column is selected from at least one of kerosene, vegetable oil, white oil, transformer oil, and liquid paraffin; The temperature of the hot oil column is 80-180°C.

8. The preparation method according to claim 1, characterized in that: In step S2, the carbonization conditions include: the carbonization temperature is 600-1200°C, and the carbonization time is 1-12 hours.

9. A nitrogen-doped spherical activated carbon prepared by the preparation method according to any one of claims 1 to 8, characterized in that: The particle size of the nitrogen-doped spherical activated carbon is 0.4 to 1.5 mm; Preferably, the doping amount of nitrogen in the nitrogen-doped spherical activated carbon is 1 to 10 wt %.

10. Use of the nitrogen-doped spherical activated carbon according to claim 9 in gas purification, water purification, blood purification, and catalyst carrier.

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