Nitrogen-doped carbon material, preparation method and application thereof, adsorption material and application thereof

Abstract

The present invention relates to the technical field of carbon material preparation, and specifically to a nitrogen-doped carbon material, a preparation method and application thereof, and an adsorption material. The method comprises: (1) mixing a carbon material precursor and a nitrogen source, and drying the obtained mixture to obtain a dry material; (2) pre-oxidizing the dry material, and carbonizing and activating the obtained pre-oxidized material under an inert gas atmosphere to obtain a carbonized activated material; (3) sequentially acid-washing and water-washing the carbonized activated material to obtain a nitrogen-doped carbon material; wherein the nitrogen source is a waste liquid containing organic amine carbonate and / or organic amine bicarbonate. The nitrogen-doped carbon material obtained by this method has a large total specific surface area, a narrow pore size, and a high microporosity. In particular, when the nitrogen-doped carbon material is used to adsorb CO2 and / or VOCs, it has a high adsorption capacity.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon material preparation, and in particular to a nitrogen-doped carbon material, a preparation method and application thereof, and an adsorption material. Background Art

[0002] Global warming has attracted increasing attention, and carbon emission reduction has also received increasing attention. CO2 adsorbents offer low pollution, excellent regeneration, no corrosion to equipment, and a wide range of precursor sources, making them a promising carbon emission reduction technology with broad application prospects.

[0003] CN103288070A provides a method for preparing N-heterocarbon using heavy organic components from coal liquefaction residue. This method uses tetrahydrofuran to extract the coal liquefaction residue to obtain the heavy organic components, which are then mixed with dicyandiamide, urea, and ammonium chloride. The mixture undergoes pre-oxidation, carbonization activation, and acid and water washing to synthesize the N-heterocarbon material. However, this method uses tetrahydrofuran as the extractant, resulting in a complex and highly hazardous synthesis process. Furthermore, the use of dicyandiamide, urea, and ammonium chloride as nitrogen sources results in the N-heterocarbon material being uneconomical and costly.

[0004] CN106902613A provides a method for preparing an amino-functional porous CO2 adsorbent. In this method, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, and polyethylene polyamine are impregnated on a porous material. However, the adsorbent synthesized by this method has a high regeneration temperature, a certain viscosity, and a certain corrosive effect on equipment, which is not conducive to the promotion and application of the adsorbent.

[0005] Therefore, a new method for preparing nitrogen-doped carbon materials is urgently needed. Summary of the Invention

[0006] The purpose of the present invention is to overcome the problems of complex process flow, high cost, corrosion to equipment, small specific surface area, low micropore content and poor thermal stability in the preparation process of N-doped carbon materials in the prior art, and to provide a new nitrogen-doped carbon material and its preparation method and application, as well as an adsorption material. The method uses waste liquid containing organic amine carbonate and / or organic amine bicarbonate as a nitrogen source, thereby reducing costs. At the same time, the nitrogen-doped carbon material has the characteristics of large specific surface area, high microporosity, etc., and has excellent adsorption effect.

[0007] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a nitrogen-doped carbon material, the method comprising the following steps:

[0008] (1) mixing a carbon material precursor and a nitrogen source, and drying the obtained mixture to obtain a dry material;

[0009] (2) pre-oxidizing the dried material, and carbonizing and activating the obtained pre-oxidized material under an inert gas atmosphere to obtain a carbonized activated material;

[0010] (3) sequentially acid-washing and water-washing the carbonized activated material to obtain a nitrogen-doped carbon material;

[0011] Wherein, the nitrogen source is waste liquid containing organic amine carbonate and / or organic amine bicarbonate.

[0012] A second aspect of the present invention provides a nitrogen-doped carbon material prepared by the method provided in the first aspect.

[0013] The third aspect of the present invention provides an adsorption material, which contains the nitrogen-doped carbon material provided by the second aspect.

[0014] The fourth aspect of the present invention provides an application of the nitrogen-doped carbon material provided in the second aspect or the adsorption material provided in the third aspect in the field of adsorption.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) The method provided by the present invention uses waste liquid containing organic amine carbonate and / or organic amine bicarbonate as a nitrogen source. During the carbonization activation process, CO2 released by the thermal decomposition of the organic amine carbonate and / or organic amine bicarbonate serves as an activator, which can increase the total specific surface area and microporosity of the nitrogen-doped carbon material. At the same time, using the waste liquid containing organic amine carbonate and / or organic amine bicarbonate as a nitrogen source increases the polarity of the adsorption material and eliminates the cost of treating the organic amine waste liquid. In addition, the method is simple to operate and does not corrode the equipment.

[0017] (2) The nitrogen-doped carbon material prepared by the present invention has a larger total specific surface area, a narrower pore size and a higher microporosity. In particular, the nitrogen-doped carbon material is used to adsorb CO2 and / or VOCs, and has a higher adsorption capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a SEM image of the nitrogen-doped carbon material S1 prepared in Example 1;

[0019] Figure 2 is a SEM image of the nitrogen-doped carbon material DS1 prepared in Comparative Example 1. DETAILED DESCRIPTION

[0020] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0021] A first aspect of the present invention provides a method for preparing a nitrogen-doped carbon material, the method comprising the following steps:

[0022] (1) mixing a carbon material precursor and a nitrogen source, and drying the obtained mixture to obtain a dry material;

[0023] (2) pre-oxidizing the dried material, and carbonizing and activating the obtained pre-oxidized material under an inert gas atmosphere to obtain a carbonized activated material;

[0024] (3) sequentially acid-washing and water-washing the carbonized activated material to obtain a nitrogen-doped carbon material;

[0025] Wherein, the nitrogen source is waste liquid containing organic amine carbonate and / or organic amine bicarbonate.

[0026] In some embodiments of the present invention, the carbon material precursor is preferably pulverized before mixing. Furthermore, preferably, the average particle size of the pulverized carbon material precursor is ≥40 mesh, preferably ≥100 mesh, and more preferably 100-500 mesh. These preferred conditions facilitate thorough mixing with the nitrogen source and activator, thereby improving reaction efficiency.

[0027] In the present invention, the carbon material precursor has a wide range of choices, as long as the carbon material precursor contains carbon. Preferably, the carbon material precursor is selected from coal chemical residues and / or petrochemical residues.

[0028] In some embodiments of the present invention, preferably, the coal chemical residue is selected from at least one of direct coal liquefaction residue, indirect coal liquefaction residue and coal tar; and the petrochemical residue is selected from petrochemical oil residue and / or petroleum asphalt.

[0029] In some embodiments of the present invention, the waste liquid containing organic amine carbonate and / or organic amine bicarbonate is preferably produced by adsorbing CO2 onto organic amine waste liquid. In the present invention, the adsorption method and conditions can be broad, as long as the organic amine in the organic amine waste liquid is converted into organic amine carbonate or organic amine bicarbonate.

[0030] In some embodiments of the present invention, the molar ratio of the organic amine to CO2 in the waste liquid containing organic amine carbonate and / or organic amine bicarbonate is preferably 1:0.1-2, for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:1, 1:1.5, 1:2, or any other value within a range consisting of any two of these values, preferably 1:0.2-1. These preferred conditions are more conducive to increasing the microporosity of the nitrogen-doped carbon adsorbent material.

[0031] In some embodiments of the present invention, preferably, the concentration of the organic amine in the organic amine waste liquid is 10-95wt%, for example, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, 80wt%, 95wt%, and any value in the range consisting of any two values, preferably 20-60wt%.

[0032] In some embodiments of the present invention, preferably, the organic amine is selected from at least one of ethanolamine, diethanolamine, ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

[0033] In some embodiments of the present invention, preferably, the ratio of the carbon material precursor in g to the nitrogen source in mL is 1:0.1-10, for example, 1:0.1, 1:0.5, 1:1, 1:2, 1:2.5, 1:3, 1:5, 1:8, 1:10, and any value in a range consisting of any two values, preferably 1:1-5. The preferred conditions are more conducive to pre-oxidation and mixing of the carbon material precursor.

[0034] In the present invention, the mixing conditions have a wide range of selections. Preferably, the mixing conditions include: a temperature of 5-40°C, preferably 15-25°C; and a time of 0.1-15 hours, preferably 0.5-10 hours.

[0035] In the present invention, a wide range of mixing methods are available, as long as the pulverized carbon material precursor and the nitrogen source are uniformly mixed. Preferably, the pulverized carbon material precursor is added to a certain amount of nitrogen source according to the above weight ratio and stirred at 5-40°C for 0.1-15 hours until no obvious liquid is left in the beaker.

[0036] In the present invention, the drying is to remove the solvent in the mixture. Preferably, the drying conditions include: a temperature of 60-150°C, preferably 80-120°C; and a time of 0.5-10 hours, preferably 2-8 hours.

[0037] In a specific embodiment of the present invention, the mixture is dried in an oven at a temperature of 60-150° C. for a time of 0.5-10 h.

[0038] In the present invention, the pre-oxidation is intended to deeply mix the precursor and the nitrogen source and to make the precursor more easily activated. Preferably, the pre-oxidation process includes: pre-oxidizing the dry material and the oxidant.

[0039] In some embodiments of the present invention, preferably, the weight ratio of the dry material to the oxidant is 1:0.1-1, for example, 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.8, 1:1, and any value in the range consisting of any two values, preferably 1:0.1-0.5.

[0040] In some embodiments of the present invention, preferably, the oxidant includes but is not limited to KNO3, NaClO2, etc.

[0041] In the present invention, the pre-oxidation conditions have a wide range of selection. Preferably, the pre-oxidation conditions include: a temperature of 180-350°C, preferably 200-300°C; a time of 0.1-5 hours, preferably 1-3 hours; and a heating rate of 1-10°C / min, preferably 3-8°C / min.

[0042] In some embodiments of the present invention, preferably, before the pre-oxidation, the mixture of the dry material and the oxidant is ground to make the sample uniformly mixed to facilitate pre-oxidation.

[0043] In some embodiments of the present invention, preferably, the average particle size of the mixture after grinding is ≥40 mesh, preferably ≥100 mesh.

[0044] In the present invention, the carbonization activation is a process of converting a carbon source into fixed carbon at high temperature and activating the fixed carbon. Preferably, the carbonization activation process comprises: carbonizing and activating the pre-oxidized material with an activator under an inert gas atmosphere.

[0045] In some embodiments of the present invention, preferably, the weight ratio of the pre-oxidized material to the activator is 1:0.1-5, for example, 1:0.1, 1:0.2, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:5, and any value in the range consisting of any two values, preferably 1:0.2-3.

[0046] In the present invention, the activating agent has a wide range of choices. Preferably, the activating agent is selected from at least one of KOH, K2CO3, KHCO3, NaOH, Na2CO3 and NaHCO3.

[0047] In some embodiments of the present invention, preferably, the carbonization activation conditions include: temperature of 500-1000°C, preferably 600-900°C; time of 0.5-4h, preferably 1-2h; heating rate of 2-10°C / min, preferably 3-5°C / min.

[0048] In some embodiments of the present invention, preferably, the inert gas is selected from at least one of nitrogen, helium, argon and neon, preferably nitrogen.

[0049] In the present invention, the acid washing is intended to remove acid-soluble substances in the carbonized activated material. Preferably, the acid washing process includes: acid washing the carbonized activated material with acid solution.

[0050] In some embodiments of the present invention, preferably, the concentration of acid in the acid solution is 0.1-5 mol / L, for example, 0.1 mol / L, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, and any value in the range consisting of any two values, preferably 0.5-2 mol / L.

[0051] In some embodiments of the present invention, preferably, the acid is an inorganic acid, preferably at least one selected from hydrochloric acid, nitric acid and sulfuric acid, preferably hydrochloric acid.

[0052] In the present invention, unless otherwise specified, the water washing is intended to remove the residual acid in the pickling material until the washed material is neutral.

[0053] According to the present invention, preferably, the method further comprises: drying the washed material.

[0054] In some embodiments of the present invention, preferably, the drying conditions include: a temperature of 80-150° C., preferably 80-120° C.; and a drying time of 0.1-6 h, preferably 0.5-4 h.

[0055] According to a particularly preferred embodiment of the present invention, the method comprises the following steps:

[0056] (1) mixing a carbon material precursor and a nitrogen source, and drying the obtained mixture to obtain a dry material;

[0057] (2) pre-oxidizing the dried material, and carbonizing and activating the obtained pre-oxidized material under an inert gas atmosphere to obtain a carbonized activated material;

[0058] (3) sequentially acid-washing and water-washing the carbonized activated material to obtain a nitrogen-doped carbon material;

[0059] Wherein, the nitrogen source is a waste liquid containing organic amine carbonate and / or organic amine bicarbonate;

[0060] The waste liquid containing organic amine carbonate and / or organic amine bicarbonate is prepared by absorbing CO2 by organic amine waste liquid; the molar ratio of organic amine to CO2 in the waste liquid containing organic amine carbonate and / or organic amine bicarbonate is 1:0.1-2.

[0061] A second aspect of the present invention provides a nitrogen-doped carbon material prepared by the method provided in the first aspect.

[0062] According to the present invention, preferably, based on the total weight of the nitrogen-doped carbon material, the doping amount of nitrogen is 0.05-2 wt%, preferably 0.1-1.5 wt%.

[0063] According to the present invention, preferably, the total specific surface area of ​​the nitrogen-doped carbon material is ≥1100 m 2 / g, preferably 1200-2500m 2 / g; average pore diameter ≤ 2.7 nm, preferably 1.5-2.7 nm; microporosity ≥ 90%, preferably 91-99%.

[0064] In the present invention, unless otherwise specified, the total specific surface area parameters and pore size parameters are measured using a BET analyzer using the N2 isothermal adsorption-desorption method; the microporosity parameter is calculated by dividing the micropore specific surface area by the total specific surface area, that is,

[0065] The third aspect of the present invention provides an adsorption material, which contains the nitrogen-doped carbon material provided by the second aspect.

[0066] In the present invention, unless otherwise specified, the adsorption material may be the nitrogen-doped carbon material provided by the present invention, or may contain other components in addition to the nitrogen-doped carbon material provided by the present invention, which will not be elaborated herein.

[0067] The fourth aspect of the present invention provides an application of the nitrogen-doped carbon material provided in the second aspect or the adsorption material provided in the third aspect in the field of adsorption.

[0068] The nitrogen-doped carbon material provided by the present invention has a large total specific surface area and a rich pore structure, and has a high adsorption effect in the adsorption field, especially for adsorbing CO2 and / or VOCs, and has a large adsorption capacity.

[0069] The present invention will be described in detail below through examples.

[0070] The room temperature in the examples and comparative examples refers to 25°C.

[0071] The physical properties of the nitrogen-doped carbon materials prepared in Examples 1-9 and Comparative Examples 1-2 were measured by the following methods:

[0072] The total specific surface area parameters and pore size parameters were measured using a BET analyzer using the N2 isothermal adsorption-desorption method;

[0073]

[0074] The adsorption amount of CO2 was measured using a thermogravimetric analyzer;

[0075] The adsorption amounts of benzene and n-hexane were both measured using the fixed bed breakthrough test method.

[0076] The physical properties of the nitrogen-doped carbon materials (S1-S9 and D1-D2) prepared in Examples 1-9 and Comparative Examples 1-2 are listed in Table 1.

[0077] Example 1

[0078] (1) 1 g of crushed carbon material precursor (coal direct liquefaction residue, average particle size of 300 mesh) and 2 mL of nitrogen source were mixed at room temperature for 0.5 h until no obvious liquid was present, and the resulting mixture was dried at 90 °C for 5 h to obtain a dry material for grinding;

[0079] The nitrogen source is a waste liquid containing organic amine carbonate, and the waste liquid containing organic amine carbonate is prepared by adsorbing CO2 on an organic amine waste liquid. The molar ratio of the organic amine to CO2 in the waste liquid containing organic amine carbonate is 1:0.5. The concentration of the organic amine in the organic amine waste liquid is 30 wt%, and the organic amine is ethanolamine.

[0080] (2) 1 g of the dried material was ground with 0.5 g of KNO3 and pre-oxidized at 300 °C for 1 h at a heating rate of 5 °C / min, and the obtained pre-oxidized material was carbonized and activated with KOH at a weight ratio of 1:2 under an inert gas atmosphere at 800 °C for 1 h at a heating rate of 5 °C / min to obtain a carbonized activated material;

[0081] (3) The carbonized activated material was acid-washed with a 2 mol / L hydrochloric acid solution, then washed with deionized water until neutral, and then dried at 120° C. for 2 h to obtain a nitrogen-doped carbon material S1.

[0082] Among them, the SEM image of nitrogen-doped carbon material S1 is as follows Figure 1 As shown by Figure 1 It can be seen that the nitrogen-doped carbon material S1 has a rich pore structure.

[0083] Example 2

[0084] (1) 1 g of crushed carbon material precursor (coal tar pitch, average particle size 200 mesh) and 2.5 mL of nitrogen source were mixed at room temperature for 5 h until no obvious liquid was found. The resulting mixture was dried at 80 °C for 6 h to obtain a dry material for grinding.

[0085] The nitrogen source is a waste liquid containing organic amine bicarbonate, and the waste liquid containing organic amine bicarbonate is prepared by adsorbing CO2 on an organic amine waste liquid. The molar ratio of the organic amine to CO2 in the waste liquid containing organic amine bicarbonate is 1:0.8, the concentration of the organic amine in the organic amine waste liquid is 25wt%, and the organic amine is ethylenediamine.

[0086] (2) 1 g of the dried material was ground with 0.5 g of KNO3 and pre-oxidized at 200 °C for 2 h at a heating rate of 5 °C / min, and the obtained pre-oxidized material was carbonized and activated with KOH at a weight ratio of 1:1 under an inert gas atmosphere at a heating rate of 5 °C / min at 750 °C for 1 h to obtain a carbonized activated material;

[0087] (3) The carbonized activated material was acid-washed with a 2 mol / L hydrochloric acid solution, then washed with deionized water until neutral, and then dried at 100° C. for 5 h to obtain a nitrogen-doped carbon material S2.

[0088] Among them, the SEM image of nitrogen-doped carbon material S2 is similar to Figure 1 similar.

[0089] Example 3

[0090] (1) 1 g of crushed carbon material precursor (petroleum asphalt, average particle size 250 mesh) and 1 mL of nitrogen source were mixed at room temperature for 3 h until no obvious liquid was found. The resulting mixture was dried at 100 °C for 5 h to obtain a dry material for grinding.

[0091] The nitrogen source is a waste liquid containing organic amine carbonate, and the waste liquid containing organic amine bicarbonate is prepared by adsorbing CO2 on an organic amine waste liquid. The molar ratio of the organic amine to CO2 in the waste liquid containing organic amine bicarbonate is 1:2. The concentration of the organic amine in the organic amine waste liquid is 35 wt%, and the organic amine is diethylenetriamine.

[0092] (2) 1 g of the dried material was ground with 0.3 g of KNO3 and pre-oxidized at 300°C for 1 h at a heating rate of 5°C / min, and the obtained pre-oxidized material was carbonized and activated with KOH at a weight ratio of 1:4 at 600°C for 5 h under an inert gas atmosphere at a heating rate of 5°C / min to obtain a carbonized activated material;

[0093] (3) The carbonized activated material was acid-washed with a 2 mol / L hydrochloric acid solution, then washed with deionized water until neutral, and then dried at 100° C. for 5 h to obtain a nitrogen-doped carbon material S3.

[0094] Among them, the SEM image of nitrogen-doped carbon material S3 is similar to Figure 1 similar.

[0095] Example 4

[0096] The method of Example 1 was followed, except that in step (1), 1 g of crushed carbon material precursor (coal direct liquefaction residue, with an average particle size of 300 mesh) and 2 mL of nitrogen source were replaced with 1 g of crushed carbon material precursor (coal direct liquefaction residue, with an average particle size of 300 mesh) and 0.5 mL of nitrogen source, and the other conditions were the same to obtain nitrogen-doped carbon material S4.

[0097] Example 5

[0098] The method of Example 1 was followed, except that in step (1), 1 g of the crushed carbon material precursor (coal direct liquefaction residue, with an average particle size of 300 mesh) was replaced with 1 g of the carbon material precursor (coal direct liquefaction residue, with an average particle size of 50 mesh), and the other conditions were the same to obtain nitrogen-doped carbon material S5.

[0099] Example 6

[0100] The method of Example 1 is followed, except that in step (1), the molar ratio of the organic amine to CO2 in the organic amine waste liquid is replaced with 1:0.1, and the other conditions are the same to obtain the nitrogen-doped carbon material S6.

[0101] Example 7

[0102] The method of Example 1 was followed, except that in step (2), 1 g of dry material and 0.5 g of KNO3 were replaced by 1 g of dry material and 2 g of KNO3, and the other conditions were the same to obtain nitrogen-doped carbon material S7.

[0103] Example 8

[0104] The method of Example 1 is followed, except that in step (2), the weight ratio of the pre-oxidized material to KOH is replaced with 1:6, and the other conditions are the same to obtain the nitrogen-doped carbon material S8.

[0105] Example 9

[0106] The method of Example 1 was followed, except that in step (1), 1 g of the crushed carbon material precursor (coal direct liquefaction residue, with an average particle size of 300 mesh) was replaced with 1 g of the carbon material precursor coconut shell, and the other conditions were the same to obtain the nitrogen-doped carbon material S9.

[0107] Comparative Example 1

[0108] The method of Example 1 was followed, except that in step (1), the nitrogen source was replaced by organic amine waste liquid, and the other conditions were the same to obtain nitrogen-doped carbon material D1.

[0109] Among them, the SEM image of nitrogen-doped carbon material D1 is as follows Figure 2 As shown by Figure 2 It can be seen that the pore structure of the nitrogen-doped carbon material D1 is significantly smaller than that of the nitrogen-doped carbon material S1 prepared in Example 1.

[0110] Comparative Example 2

[0111] The method of Example 1 is followed, except that in step (2), the dry material is directly carbonized and activated with KOH in a weight ratio of 1:2 under an inert gas atmosphere, and the other conditions are the same to obtain a nitrogen-doped carbon material D2.

[0112] Table 1

[0113]

[0114] From the results in Table 1, it can be seen that the nitrogen-doped carbon material prepared by using the waste liquid containing organic amine carbonate and / or organic amine bicarbonate as the nitrogen source has the characteristics of large specific surface area, small average pore size and high microporosity.

[0115] Test Example 1

[0116] The nitrogen-doped carbon materials (S1-S9 and D1-D2) prepared in Examples 1-9 and Comparative Examples 1-2 were respectively subjected to adsorption of CO2 at 40°C. The adsorption amounts of CO2 are listed in Table 2.

[0117] Test Example 2

[0118] The nitrogen-doped carbon materials (S1-S9 and D1-D2) prepared in Examples 1-9 and Comparative Examples 1-2 were respectively subjected to benzene adsorption at 25°C. The amounts of benzene adsorbed are listed in Table 2.

[0119] Test Example 3

[0120] The nitrogen-doped carbon materials (S1-S9 and D1-D2) prepared in Examples 1-9 and Comparative Examples 1-2 were respectively adsorbed with n-hexane at 25°C. The adsorption amounts of n-hexane are listed in Table 2.

[0121] Table 2

[0122] <![CDATA[CO2 adsorption capacity, wt%]]> Benzene adsorption amount, wt% Adsorption amount of n-hexane, wt% Example 1 4.6 13.7 12.1 Example 2 5.4 11.8 10.9 Example 3 4.4 11.5 10.7 Example 4 4.2 12.3 11.2 Example 5 4.5 13.3 11.8 Example 6 4.5 12.5 11.2 Example 7 4.6 13.0 11.7 Example 8 4.1 11.3 10.6 Example 9 3.6 10.5 9.9 Comparative Example 1 3.1 8.7 6.8 Comparative Example 2 3.9 9.7 8.8

[0123] It can be seen from the data in Table 2 that compared with Comparative Examples 1-2, the adsorption material made from the nitrogen-doped carbon material provided by the present invention has a better adsorption effect on CO2, and also shows a good adsorption effect on VOCs gases such as benzene and n-hexane.

[0124] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a nitrogen-doped carbon material, characterized in that: The method comprises the following steps: (1) mixing a carbon material precursor and a nitrogen source, and drying the resulting mixture to obtain a dry material; (2) pre-oxidizing the dried material, and carbonizing and activating the obtained pre-oxidized material under an inert gas atmosphere to obtain a carbonized activated material; (3) sequentially acid-washing and water-washing the carbonized activated material to obtain a nitrogen-doped carbon material; Wherein, the nitrogen source is a waste liquid containing organic amine carbonate and / or organic amine bicarbonate; the waste liquid containing organic amine carbonate and / or organic amine bicarbonate is prepared by absorbing CO2 by organic amine waste liquid; The molar ratio of organic amine to CO2 in the waste liquid containing organic amine carbonate and / or organic amine bicarbonate is 1:0.1-2; The organic amine is at least one selected from ethanolamine, diethanolamine, ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine.

2. The method according to claim 1, wherein Before the mixing, the carbon material precursor is pulverized.

3. The method according to claim 1, wherein The average particle size of the carbon material precursor is ≥40 mesh.

4. The method according to claim 3, wherein: The average particle size of the carbon material precursor is ≥100 mesh.

5. The method according to claim 1, wherein The carbon material precursor is selected from coal chemical residue and / or petrochemical residue.

6. The method according to claim 5, wherein: The coal chemical residue is selected from at least one of coal direct liquefaction residue, coal indirect liquefaction residue and coal tar pitch; the petrochemical residue is selected from petrochemical oil residue and / or petroleum asphalt.

7. The method according to claim 1, wherein The molar ratio of organic amine to CO2 in the waste liquid containing organic amine carbonate and / or organic amine bicarbonate is 1:0.2-1.

8. The method according to claim 1, wherein The concentration of the organic amine in the organic amine waste liquid is 20-60 wt %.

9. The method according to claim 1, wherein: The ratio of the carbon material precursor in g to the nitrogen source in mL is 1:0.1-10.

10. The method according to claim 9, wherein: The ratio of the carbon material precursor in g to the nitrogen source in mL is 1:1-5.

11. The method according to claim 1, wherein The mixing conditions include: temperature of 5-40° C.; and time of 0.1-15 h.

12. The method according to claim 11, wherein The mixing conditions include: temperature of 15-25° C.; time of 0.5-10 h.

13. The method according to claim 1, wherein The drying conditions include: temperature of 60-150° C.; time of 0.5-10 h.

14. The method according to claim 13, wherein The drying conditions include: temperature of 80-120° C.; time of 2-8 hours.

15. The method according to claim 1, wherein The pre-oxidation process includes: mixing the dry material and an oxidant for pre-oxidation.

16. The method according to claim 15, wherein The weight ratio of the dry material to the oxidant is 1:0.1-1.

17. The method according to claim 16, wherein The weight ratio of the dry material to the oxidant is 1:0.1-0.

5.

18. The method according to claim 15, wherein The pre-oxidation conditions include: temperature of 180-350° C.; time of 0.1-5 hours; and heating rate of 1-10° C. / min.

19. The method according to claim 18, wherein The pre-oxidation conditions include: temperature of 200-300° C.; time of 1-3 hours; and heating rate of 3-8° C. / min.

20. The method according to claim 1, wherein The carbonization and activation process includes: carbonizing and activating the pre-oxidized material and an activator under an inert gas atmosphere.

21. The method according to claim 20, wherein The weight ratio of the pre-oxidized material to the activator is 1:0.1-5.

22. The method according to claim 21, wherein The weight ratio of the pre-oxidized material to the activator is 1:0.2-3.

23. The method according to claim 20, wherein The activator is selected from at least one of KOH, K2CO3, KHCO3, NaOH, Na2CO3 and NaHCO3.

24. The method according to claim 20, wherein The carbonization activation conditions include: temperature of 500-1000° C.; time of 0.5-4 h; and heating rate of 2-10° C. / min.

25. The method according to claim 24, wherein The carbonization activation conditions include: temperature of 600-900° C.; time of 1-2 hours; and heating rate of 3-5° C. / min.

26. The method according to claim 20, wherein The inert gas is selected from at least one of nitrogen, helium, argon and neon.

27. The method according to claim 26, wherein The inert gas is nitrogen.

28. The method according to claim 1, wherein The pickling process includes: pickling the carbonized activated material with acid solution.

29. The method according to claim 28, wherein The acid concentration in the acid solution is 0.1-5 mol / L.

30. The method according to claim 29, wherein The acid concentration in the acid solution is 0.5-2 mol / L.

31. The method according to claim 29, wherein The acid is an inorganic acid.

32. The method according to claim 31, wherein The inorganic acid is selected from at least one of hydrochloric acid, nitric acid and sulfuric acid.

33. The method of claim 1, wherein The method further comprises: drying the washed material.

34. A nitrogen-doped carbon material obtained by the method according to any one of claims 1 to 33.

35. The nitrogen-doped carbon material according to claim 34, wherein Based on the total weight of the nitrogen-doped carbon material, the doping amount of nitrogen is 0.05-2 wt %.

36. The nitrogen-doped carbon material according to claim 35, wherein Based on the total weight of the nitrogen-doped carbon material, the doping amount of nitrogen is 0.1-1.5 wt %.

37. The nitrogen-doped carbon material according to claim 34, wherein The total specific surface area of ​​the nitrogen-doped carbon material is ≥1100 m 2 / g; average pore size ≤2.7 nm; Microporosity ≥90%.

38. The nitrogen-doped carbon material according to claim 37, wherein The total specific surface area of ​​the nitrogen-doped carbon material is 1200-2500 m 2 / g; average pore size is 1.5-2.7 nm; microporosity is 91-99%.

39. An adsorption material, characterized in that The adsorption material contains the nitrogen-doped carbon material according to any one of claims 34 to 38.

40. Use of the nitrogen-doped carbon material according to any one of claims 34 to 38 or the adsorption material according to claim 39 in the field of adsorption.

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