A boron nitride-based material, a preparation method therefor, and an application thereof

Abstract

The application belongs to the technical field of adsorbents, and provides a boron nitride-based material, a preparation method and application thereof, the method comprising the following steps: mixing boric acid, melamine and water, and then adding a metal salt solution to obtain a precursor; and pyrolyzing the precursor in a protective atmosphere to obtain the boron nitride-based material. The porous boron nitride fiber material loaded with basic metal ions is prepared by a pyrolysis method, and the abundant structural defects, low density, excellent chemical inertness, strong oxidation resistance and non-toxicity of the porous boron nitride fiber material make it suitable to be a carrier of metal ions, thereby being conducive to further improving the carbon dioxide adsorption capacity of pure boron nitride material. After being loaded with basic metal ions, the boron nitride material enhances the electrostatic interaction and adsorption energy of the material to carbon dioxide, thereby promoting the adsorption of the material to carbon dioxide.

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 massive emission of CO2 from fossil fuel combustion is a major cause of global warming. Carbon capture, utilization, and storage (CCUS) technology continues to play a vital role in global carbon reduction. Specifically, CCUS involves separating CO2 from industrial or energy-using processes (such as power generation, manufacturing, and oil and gas production) and the atmosphere, and then directly utilizing or injecting it into underground formations to achieve permanent CO2 reduction and storage. CO2 capture is considered a necessary step in curbing carbon emissions from fossil fuel combustion.

[0003] Solid adsorbents used for CO2 capture are generally porous materials with a large specific surface area, such as porous carbon, zeolite, 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 h.

[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 holding 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 present 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 steps of: mixing boric acid, melamine, and water, then adding a metal salt solution to obtain a precursor; and pyrolyzing the precursor in a protective atmosphere to obtain the boron nitride-based material. The present invention uses pyrolysis to prepare porous boron nitride fiber materials loaded with alkaline metal ions. The porous boron nitride fibers are suitable as metal ion carriers due to their abundant structural defects, low density, excellent chemical inertness, strong oxidation resistance, and non-toxicity, thereby further improving the carbon dioxide adsorption capacity of pure boron nitride materials.

[0019] Boron nitride materials are prepared using a pyrolysis method. Compared to traditional chemical vapor deposition methods, pyrolysis-prepared boron nitride materials have a higher specific surface area, a richer pore structure, and excellent 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 materials, 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 a 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; and 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 even 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 holding 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 present 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 with reference to the embodiments, but they should not be construed as limiting the scope of protection 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, stir continuously at 85°C for 2 h, weigh 0.0035 mol of Fe(NO3)3·9H2O and dissolve it in water to make 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 recorded as BN-Fe.

[0041] Example 2

[0042] Mix 0.16 mol of boric acid, 0.08 mol of melamine and 1000 mL of water, stir continuously at 85 ° C for 2 h, weigh 0.003 mol of Cu(NO3)2·3H2O and dissolve it in water to prepare a 1 mol / L metal salt solution, then add it to the above mixture solution, stir for 2 h, cool naturally to room temperature and dry 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 recorded as BN-Cu.

[0044] Example 3

[0045] Mix 0.16 mol of boric acid, 0.08 mol of melamine and 1000 mL of water, stir continuously at 85°C for 3 h, weigh 0.0032 mol of Ni(NO3)2·6H2O and dissolve it in water to prepare a 1.8 mol / L metal salt solution, then add it to the above mixture solution, stir for 10 h, cool naturally to room temperature and dry 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, which was recorded as BN-Ni.

[0047] Example 4

[0048] Mix 0.16 mol of boric acid, 0.08 mol of melamine and 1000 mL of water, stir continuously at 85 ° C for 3 hours, weigh 0.0032 mol of Co(NO3)2·6H2O and dissolve it in water to prepare a 0.8 mol / L metal salt solution, then add it to the above mixture solution, stir for 5 hours, cool naturally to room temperature and dry 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 recorded 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 amount 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 FIG. 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] As can be seen from the above examples, the present invention prepares porous boron nitride fiber materials loaded with alkaline metal ions by pyrolysis. The porous boron nitride fiber materials have rich structural defects, low density, excellent chemical inertness, strong antioxidant properties and non-toxicity, making them suitable as carriers of metal ions, which is conducive to further improving the carbon dioxide adsorption capacity of pure boron nitride materials.

[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 principles of the present invention. These improvements and modifications should also be regarded as within 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) pyrolyzing the precursor in a protective atmosphere to obtain the boron nitride-based material; The metal salt of the metal salt solution in step (1) is Cu(NO3)2·3H2O; 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; 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; The target temperature of the pyrolysis in step (2) is 800-1000° C., and the holding time after reaching the target temperature is 4-6 hours.

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

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

4. The method for preparing a boron nitride-based material according to claim 3, wherein: The heating rate of the pyrolysis in step (2) is 2 to 20°C / min.

5. The boron nitride-based material prepared by the method for preparing a boron nitride-based material according to any one of claims 1 to 4.

6. Use of the boron nitride-based material according to claim 5 in adsorbing carbon dioxide.

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