Boron nitride-based material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of adsorbents, and provides a boron nitride-based material and a preparation method and application thereof.The method comprises the following steps that boric acid, melamine and water are mixed and then added into a metal salt solution, and a precursor is obtained; and pyrolyzing the precursor in a protective atmosphere to obtain the boron nitride-based material. The porous boron nitride fiber material loaded with the alkaline metal ions is prepared through a pyrolysis method, and the porous boron nitride fiber material is rich in structural defects, low in density, excellent in chemical inertness, high in oxidation resistance and free of toxicity, so that the porous boron nitride fiber material is suitable for being used as a carrier of the metal ions; therefore, the carbon dioxide adsorption capacity of the pure boron nitride material is further improved. According to the boron nitride material loaded with the alkaline metal ions, the electrostatic interaction and adsorption energy of the boron nitride material to carbon dioxide are enhanced, so that the adsorption of the boron nitride material to the carbon dioxide is promoted.

Description

Technical Field

[0001] The present invention relates to the technical field of adsorbents, and in particular to a boron nitride-based material and a preparation method and application thereof. Background Art

[0002] The large amount of CO2 emitted by the combustion of fossil fuels is the main cause of global warming. Carbon capture, utilization and storage (CCUS) technology continues to play an important role in the global carbon emission reduction process. Specifically, it refers to the process of separating CO2 from industrial processes or energy utilization processes (such as power generation, manufacturing, oil and gas production processes, etc.) and the atmosphere and directly utilizing or injecting it into underground layers to achieve permanent CO2 emission reduction and storage. Among them, CO2 capture is considered a necessary step to curb carbon emissions from the combustion of fossil fuels.

[0003] Solid adsorbents used for CO2 capture are generally porous materials with large specific surface areas, such as porous carbon, zeolites, metal organic frameworks, covalent organic frameworks, etc. This type of porous material has a wider adsorption temperature range and higher adsorption efficiency, but its preparation cost is high and its recyclability is poor. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a boron nitride-based material and a preparation method and application thereof.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a boron nitride-based material, comprising the following steps:

[0007] (1) mixing boric acid, melamine and water and adding a metal salt solution to obtain a precursor;

[0008] (2) In a protective atmosphere, the precursor is pyrolyzed to obtain the boron nitride-based material.

[0009] Preferably, the molar volume ratio of boric acid, melamine and water in step (1) is 0.1-0.2 mol: 0.05-0.1 mol: 800-1200 mL.

[0010] Preferably, the mixing temperature in step (1) is 85-95° C. and the mixing time is 2-4 hours.

[0011] Preferably, the metal salt of the metal salt solution in step (1) is one or more of Fe(NO3)3·9H2O, Cu(NO3)2·3H2O, Ni(NO3)2·6H2O and Co(NO3)2·6H2O.

[0012] Preferably, in step (1), the molar ratio of boric acid to the metal salt in the metal salt solution is 0.1-0.2:0.003-0.004.

[0013] Preferably, the concentration of the metal salt solution in step (1) is 0.5 to 2 mol / L.

[0014] Preferably, the heating rate of the pyrolysis in step (2) is 2 to 20°C / min.

[0015] Preferably, the target temperature of the pyrolysis in step (2) is 800-1000° C., and the insulation time after reaching the target temperature is 4-6 hours.

[0016] The present invention also provides a boron nitride-based material prepared by the method for preparing the boron nitride-based material.

[0017] The invention also provides application of the boron nitride-based material in adsorbing carbon dioxide.

[0018] The present invention provides a method for preparing a boron nitride-based material, comprising the following steps: mixing boric acid, melamine and water and adding a metal salt solution to obtain a precursor; pyrolyzing the precursor in a protective atmosphere to obtain the boron nitride-based material. The present invention prepares a porous boron nitride fiber material loaded with alkaline metal ions by pyrolysis. The porous boron nitride fiber has abundant structural defects, low density, excellent chemical inertness, strong oxidation resistance and non-toxicity, making it suitable as a carrier of metal ions, thereby facilitating further improving the carbon dioxide adsorption capacity of the pure boron nitride material.

[0019] Boron nitride materials are prepared by pyrolysis. Compared with traditional chemical vapor deposition, the boron nitride materials prepared by pyrolysis have higher specific surface area, richer pore structure and better thermal stability. The preparation method is simple, low cost, highly controllable and environmentally friendly. The boron nitride materials obtained by this method have significant advantages in carbon dioxide adsorption.

[0020] The boron nitride material loaded with alkaline metal ions enhances its electrostatic interaction and adsorption energy with carbon dioxide, thereby promoting its adsorption of carbon dioxide.

[0021] Compared with pure boron nitride adsorbent material, the alkaline metal-loaded porous boron nitride adsorbent material prepared by the present invention has higher adsorption efficiency and recyclability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is the carbon dioxide adsorption diagram of the boron nitride-based materials of Examples 1 to 4 and Comparative Example 1. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing a boron nitride-based material, comprising the following steps:

[0024] (1) mixing boric acid, melamine and water and adding a metal salt solution to obtain a precursor;

[0025] (2) In a protective atmosphere, the precursor is pyrolyzed to obtain the boron nitride-based material.

[0026] In the present invention, the molar volume ratio of boric acid, melamine and water in step (1) is preferably 0.1-0.2 mol: 0.05-0.1 mol: 800-1200 mL, more preferably 0.12-0.18 mol: 0.06-0.09 mol: 850-1150 mL, and more preferably 0.14-0.16 mol: 0.07-0.08 mol: 900-1100 mL.

[0027] In the present invention, the mixing temperature in step (1) is preferably 85-95°C, more preferably 86-94°C, more preferably 88-92°C; the mixing time is preferably 2-4h, more preferably 2.5-3.5h, more preferably 2.8-3.2h; stirring is maintained during the mixing process.

[0028] In the present invention, the metal salt of the metal salt solution in step (1) is one or more of Fe(NO3)3·9H2O, Cu(NO3)2·3H2O, Ni(NO3)2·6H2O and Co(NO3)2·6H2O.

[0029] In the present invention, the molar ratio of boric acid to the metal salt in the metal salt solution in step (1) is preferably 0.1-0.2:0.003-0.004, more preferably 0.12-0.18:0.0032-0.0038, and more preferably 0.14-0.16:0.0034-0.0036.

[0030] In the present invention, the concentration of the metal salt solution in step (1) is preferably 0.5 to 2 mol / L, more preferably 1 to 1.5 mol / L, and even more preferably 1.1 to 1.3 mol / L.

[0031] In the present invention, the metal salt solution is added and stirred, and the stirring time is preferably 2 to 10 hours, more preferably 3 to 9 hours, and more preferably 4 to 6 hours. After the stirring is completed, it is naturally cooled to room temperature and then dried to constant weight to obtain a precursor.

[0032] In the present invention, the protective atmosphere in step (2) is nitrogen or argon.

[0033] In the present invention, the heating rate of the pyrolysis in step (2) is preferably 2 to 20°C / min, more preferably 5 to 15°C / min, and more preferably 8 to 12°C / min.

[0034] In the present invention, the target temperature of the pyrolysis in step (2) is preferably 800-1000°C, more preferably 850-950°C, and more preferably 880-920°C; the insulation time after reaching the target temperature is preferably 4-6h, more preferably 4.5-5.5h, and more preferably 4.8-5.2h.

[0035] The present invention also provides a boron nitride-based material prepared by the method for preparing the boron nitride-based material.

[0036] The invention also provides application of the boron nitride-based material in adsorbing carbon dioxide.

[0037] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0038] Example 1

[0039] Mix 0.16 mol of boric acid, 0.08 mol of melamine and 1000 mL of water, and stir continuously at 85 °C for 2 h. Weigh 0.0035 mol of Fe(NO3)3·9H2O and dissolve it in water to prepare a 1.5 mol / L metal salt solution, then add it to the above mixture solution, stir for 5 h, cool naturally to room temperature and dry to constant weight to obtain an iron-loaded precursor.

[0040] The precursor was placed in an argon atmosphere, heated to 900°C at a heating rate of 10°C / min, and then pyrolyzed for 4 hours to obtain a boron nitride-based material, which was denoted as BN-Fe.

[0041] Example 2

[0042] 0.16 mol of boric acid, 0.08 mol of melamine and 1000 mL of water were mixed and stirred continuously at 85 °C for 2 h. 0.003 mol of Cu(NO3)2·3H2O was weighed and dissolved in water to prepare a 1 mol / L metal salt solution, which was then added to the above mixture solution and stirred for 2 h. The mixture was naturally cooled to room temperature and dried to constant weight to obtain a copper-loaded precursor.

[0043] The precursor was placed in an argon atmosphere, heated to 900°C at a heating rate of 10°C / min, and then pyrolyzed for 4 hours to obtain a boron nitride-based material, which was denoted as BN-Cu.

[0044] Example 3

[0045] 0.16 mol of boric acid, 0.08 mol of melamine and 1000 mL of water were mixed and stirred continuously at 85 °C for 3 h. 0.0032 mol of Ni(NO3)2·6H2O was weighed and dissolved in water to prepare a 1.8 mol / L metal salt solution, which was then added to the above mixture solution and stirred for 10 h. The mixture was naturally cooled to room temperature and dried to constant weight to obtain a nickel-loaded precursor.

[0046] The precursor was placed in a nitrogen atmosphere, heated to 900°C at a heating rate of 10°C / min, and then pyrolyzed for 4 hours to obtain a boron nitride-based material, denoted as BN-Ni.

[0047] Example 4

[0048] 0.16 mol of boric acid, 0.08 mol of melamine and 1000 mL of water were mixed and stirred continuously at 85 °C for 3 h. 0.0032 mol of Co(NO3)2·6H2O was weighed and dissolved in water to prepare a 0.8 mol / L metal salt solution, which was then added to the above mixture solution and stirred for 5 h. The mixture was naturally cooled to room temperature and dried to constant weight to obtain a cobalt-loaded precursor.

[0049] The precursor was placed in a nitrogen atmosphere, heated to 900°C at a heating rate of 10°C / min, and then pyrolyzed for 4 hours to obtain a boron nitride-based material, which was denoted as BN-Co.

[0050] Comparative Example 1

[0051] 0.16 mol of boric acid, 0.08 mol of melamine and 1000 mL of water were mixed, stirred continuously at 85° C. for 2 h, cooled naturally to room temperature and dried to constant weight to obtain a precursor.

[0052] The precursor was placed in an argon atmosphere, heated to 900°C at a heating rate of 10°C / min, and then pyrolyzed for 4 hours to obtain a boron nitride-based material, denoted as BN.

[0053] The materials obtained in Examples 1 to 4 and Comparative Example 1 were subjected to performance tests, and the test process was as follows: A thermogravimetric analyzer was used to detect the adsorption and desorption performance of the boron nitride-based adsorbent on carbon dioxide. 10 mg of the boron nitride-based adsorbent was placed in a ceramic crucible, argon gas (50 mL / min) was introduced, and the mixture was heated to 40°C at a rate of 10°C / min and maintained for 40 minutes to remove any molecules adsorbed in the air. The argon gas was then converted to carbon dioxide gas (50 mL / min) for CO2 adsorption, and maintained for 30 minutes to reach the saturated adsorption equilibrium of the sample. Finally, the gas was converted to argon gas (50 mL / min) again, and heated to 120°C at a rate of 10°C / min and maintained for 90 minutes to remove the CO2 adsorbed from the mixed gas. The adsorption of carbon dioxide was calculated based on the weight change of the boron nitride-based adsorbent during the carbon dioxide capture process, and the results are shown in Figure 2. Figure 1 As shown. Figure 1 It can be concluded that the method of the present invention can significantly improve the adsorption efficiency of carbon dioxide by boron nitride-based adsorbent.

[0054] It can be seen from the above embodiments that the present invention prepares a porous boron nitride fiber material loaded with alkaline metal ions by a pyrolysis method. The porous boron nitride fiber material has rich structural defects, low density, excellent chemical inertness, strong antioxidant properties and non-toxicity, making it suitable as a carrier of metal ions, which is beneficial to further improve the carbon dioxide adsorption capacity of the pure boron nitride material.

[0055] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a boron nitride-based material, characterized in that: It includes the following steps: (1) mixing boric acid, melamine and water and adding a metal salt solution to obtain a precursor; (2) In a protective atmosphere, the precursor is pyrolyzed to obtain the boron nitride-based material.

2. The method for preparing a boron nitride-based material according to claim 1, characterized in that: The molar volume ratio of boric acid, melamine and water in step (1) is 0.1-0.2 mol: 0.05-0.1 mol: 800-1200 mL.

3. The method for preparing a boron nitride-based material according to claim 1 or 2, characterized in that: The mixing temperature in step (1) is 85-95° C. and the mixing time is 2-4 hours.

4. The method for preparing a boron nitride-based material according to claim 3, characterized in that: The metal salt of the metal salt solution in step (1) is one or more of Fe(NO3)3·9H2O, Cu(NO3)2·3H2O, Ni(NO3)2·6H2O and Co(NO3)2·6H2O.

5. The method for preparing a boron nitride-based material according to claim 1 or 4, characterized in that: In step (1), the molar ratio of boric acid to the metal salt in the metal salt solution is 0.1-0.2:0.003-0.

004.

6. The method for preparing a boron nitride-based material according to claim 5, characterized in that: The concentration of the metal salt solution in step (1) is 0.5-2 mol / L.

7. The method for preparing a boron nitride-based material according to claim 6, characterized in that: The heating rate of the pyrolysis in step (2) is 2 to 20°C / min.

8. The method for preparing a boron nitride-based material according to claim 1 or 7, characterized in that: The target temperature of the pyrolysis in step (2) is 800-1000° C., and the insulation time after reaching the target temperature is 4-6 hours.

9. The boron nitride-based material prepared by the method for preparing a boron nitride-based material according to any one of claims 1 to 8.

10. Use of the boron nitride-based material according to claim 9 in adsorbing carbon dioxide.

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