A MOF material, a preparation method and application thereof

Abstract

The application discloses a MOF material and a preparation method and application thereof. The preparation method comprises the following steps: dipping activated MIL101(Cr) material and tri(2-aminoethyl)amine (TAEA) in an ethanol solvent, and then removing the ethanol solvent to obtain the MOF material, wherein the mass ratio of the activated MIL101(Cr) material and the polyamine ligand is 1:(1-1.5). The preparation method has mild reaction conditions, is easy to operate, and uses cheap raw materials, and is easy to realize industrial amplification. The prepared MOF material can be used as an adsorbent for directly capturing carbon dioxide from air, has a small take-off pressure for adsorbing carbon dioxide, can effectively reduce the cost, has good stability, and has a good industrial application prospect.

Description

Technical Field

[0001] This invention relates to a MOF material, its preparation method, and its applications. Background Technology

[0002] With accelerated industrialization, global CO2 emissions continue to rise, making the reduction of greenhouse gas emissions, especially carbon dioxide (CO2), a major challenge facing the international community. Direct air capture (DAC) technology has attracted much attention as a key pathway to achieving carbon neutrality. By directly separating and capturing carbon dioxide from the atmosphere, it is expected to provide important support for achieving carbon neutrality goals. However, existing DAC technologies still face many challenges in terms of energy consumption, cost, and material stability.

[0003] Traditional adsorbents such as activated carbon and molecular sieves suffer from low adsorption capacity, poor selectivity, and high regeneration energy consumption in carbon dioxide capture, making it difficult to meet the needs of large-scale industrial applications. Metal-organic frameworks (MOFs), with their high specific surface area, tunable pore structure, and abundant active sites, have shown great potential in the field of carbon dioxide adsorption. However, MOF materials still face bottlenecks in terms of stability, recyclability, and preparation cost. There is an urgent need to develop MOF adsorbents and their preparation methods that combine high adsorption performance with practical application value to promote the industrialization of direct air capture of carbon dioxide technology. Summary of the Invention

[0004] The technical problem this invention aims to solve is to overcome the shortcomings of existing MOF materials, such as low adsorption capacity, poor adsorption selectivity, high regeneration energy consumption, and poor stability. This invention provides a MOF material, its preparation method, and its applications. The MOF material of this invention has uniform size and can be used as an adsorbent for direct air capture of carbon dioxide. It can achieve efficient adsorption even in low-concentration carbon dioxide environments, has low regeneration energy consumption, effectively reducing the cost of direct air capture of carbon dioxide. Furthermore, it exhibits good stability, mild reaction conditions, ease of operation, inexpensive raw materials, and is easily scaled up industrially, showing promising prospects for industrial application.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution:

[0006] This invention provides a method for preparing MOF materials, which includes the following steps:

[0007] The activated MIL101(Cr) material (referring to unmodified MIL101(Cr) material) and the polyamine ligand were impregnated in an ethanol solvent, and the ethanol solvent was removed to obtain the MOF material.

[0008] The polyamine ligand is tris(2-aminoethyl)amine (TAEA); the mass ratio of the activated MIL101(Cr) material to the polyamine ligand is 1:(1-1.5).

[0009] In one embodiment, the mass ratio of the activated MIL101(Cr) material to the polyamine ligand can be 1:1 or 1:1.5.

[0010] In one embodiment, the mass-to-volume ratio of the activated MIL101(Cr) material to the ethanol solvent can be (10-50):1 g / L, preferably (20-40):1 g / L, for example 30:1.

[0011] In one embodiment, the impregnation operation may involve dispersing the activated MIL101(Cr) material and the polyamine ligand in an ethanol solvent using ultrasound. The ultrasound is performed in two steps: first, the activated MIL101(Cr) material and the polyamine ligand are dispersed separately in the ethanol solvent; second, the dispersions of the activated MIL101(Cr) material and the polyamine ligand are mixed using ultrasound.

[0012] In one approach, the duration of the first ultrasound can be 5-20 minutes, preferably 5-15 minutes, such as 10 minutes.

[0013] In one protocol, the second ultrasound may take 15-60 minutes, such as 20 minutes, 30 minutes, or 40 minutes.

[0014] In one embodiment, the removal of the ethanol solvent may be carried out at 40-60°C (e.g., 50°C) for 15-30 hours (e.g., 20 hours), or more preferably, under a nitrogen atmosphere.

[0015] In one embodiment, the preparation method of the activated MIL101 (Cr) material may include the following steps:

[0016] MIL101(Cr) was soaked in solvent, centrifuged, washed, and dried to obtain activated MIL101(Cr) material.

[0017] In one embodiment, the solvent used for immersion is an amide solvent, such as N,N-dimethylformamide.

[0018] In one embodiment, during the soaking step, the mass-to-volume ratio of MIL101(Cr) to the solvent can be 10-50 g / L, for example, 30 g / L.

[0019] In one embodiment, the soaking temperature can be 60-80°C, for example, 70°C.

[0020] In one embodiment, the soaking time can be 10-14 hours, for example, 12 hours.

[0021] In one approach, the soaking may be performed multiple times, such as twice.

[0022] In one embodiment, the centrifugal washing may be performed sequentially with an amide solvent and an alcohol solvent, for example, with N,N-dimethylformamide and methanol, respectively.

[0023] In one embodiment, the mass-to-volume ratio of the amount of MIL101 (Cr) to the amount of solvent used in the centrifugal washing can be 10-50 g / L, for example, 30 g / L.

[0024] In one embodiment, the centrifugal washing with N,N-dimethylformamide is performed 2-5 times per day (e.g., 3 times), for a total of 6-10 times (e.g., 9 times).

[0025] In one embodiment, the centrifugal washing with methanol can be performed 2-5 times per day (e.g., 3 times), for a total of 9-15 times (e.g., 9 times).

[0026] In one embodiment, the centrifugal washing speed can be 7000-9000 rpm, for example, 8000 rpm.

[0027] In one embodiment, the centrifugal washing time can be 2-4 minutes, for example, 3 minutes.

[0028] In one embodiment, the drying temperature can be 60-80°C, for example, 70°C.

[0029] In one embodiment, the drying time can be 14-16 hours, for example, 15 hours.

[0030] In one embodiment, the MIL101(Cr) material can be prepared by conventional methods in the art. Preferably, the preparation method of the MIL101(Cr) material includes the following steps: in a solvent, chromium(III) nitrate nonahydrate and terephthalic acid are reacted to obtain the product MIL-101(Cr).

[0031] In one embodiment, the solvent in the preparation method of the MIL101(Cr) material is deionized water.

[0032] In one embodiment, the mass ratio of the solvent to the chromium(III) nitrate nonahydrate can be (8-12):1, preferably (9-11):1, for example 10:1.

[0033] In one embodiment, the mass ratio of the terephthalic acid to the chromium(III) nitrate nonahydrate can be 1:(2-3), for example, 1:2.4.

[0034] In one embodiment, the reaction temperature in the preparation method of the MIL101 (Cr) material can be 180-220℃, for example, 200℃.

[0035] In one embodiment, the reaction time in the preparation method of the MIL101 (Cr) material can be 14-18 hours, for example, 16 hours.

[0036] The present invention also provides MOF materials prepared by the preparation method of MOF materials as described above.

[0037] The present invention also provides an adsorbent comprising the MOF material as described above.

[0038] In this invention, the particle size of the MOF material can be 337-348 nm, for example 337.3 nm, 344.9 nm and 347.5 nm.

[0039] In this invention, the MOF material has a specific surface area of ​​840 m² / g and a pore volume of 0.4137 cc / g.

[0040] The present invention also provides the application of the MOF material and the adsorbent as described above in gas adsorption and gas storage; preferably in the adsorption and storage of carbon dioxide.

[0041] The present invention also provides the application of MOF materials prepared by the aforementioned method as adsorbents in direct air capture of carbon dioxide.

[0042] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0043] The reagents and raw materials used in this invention are all commercially available.

[0044] The significant advantages of this invention are: the MOF adsorbent material of this invention can be used for direct air capture of carbon dioxide, exhibiting a low adsorption initiation pressure for carbon dioxide, effectively meeting the requirements of direct air capture technology, and demonstrating good adsorption stability. In a preferred embodiment of this invention, the MOF adsorbent material for direct air capture of carbon dioxide can achieve an adsorption pressure of 75 cm⁻¹ under a carbon dioxide partial pressure of 400 ppm. 3 g -1 Adsorption capacity. Detailed Implementation

[0045] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0046] Example 1

[0047] Add Cr(NO3)3·9H2O (chromium(III) nitrate nonahydrate) (3.0 g) and H2BDC (terephthalic acid) (1.26 g) to 30 mL of deionized water. After sonicating for 30 minutes to disperse evenly, transfer to a 100 mL high-pressure reactor and react in a 200 °C oven for 16 hours. After cooling, collect the product (1.5 g) by centrifugation. Disperse the reaction product MIL101(Cr) (1.5 g) in N,N-dimethylformamide solution (30 mL) and soak at 70 °C for 12 hours. After cooling, centrifuge and wash, repeating this process twice. Then wash with N,N-dimethylformamide and centrifuge (30 mL DMF) 3 times a day for a total of more than 6 times. Finally, wash with methanol and centrifuge (30 mL) 3 times a day for a total of more than 9 times.

[0048] Centrifugation was performed at 8000 rpm for 3 minutes each time, followed by drying in a vacuum oven at 70°C for 15 hours to obtain activated MIL101(Cr) material (0.9 g).

[0049] Subsequently, 60 mg of activated MIL101(Cr) and 60 mg of TAEA were dispersed in 2 mL of ethanol and sonicated for 10 minutes respectively. Then, the dispersions of MIL101(Cr) and tris(2-aminoethyl)amine (TAEA) were mixed and sonicated for 30 minutes for impregnation treatment (the material was green before impregnation and light yellow after impregnation). The mixed solution was then placed open in a metal bath, and a tube connected to nitrogen gas was connected to the metal bath. Nitrogen gas was introduced for 10 minutes, and the temperature was raised to 50°C. The reaction was carried out for 20 hours, and the ethanol was evaporated to remove it, thus obtaining the adsorbent.

[0050] Example 2

[0051] The only difference from Example 1 is that the mass of TAEA is 30 mg, resulting in an adsorbent.

[0052] Example 3

[0053] The only difference from Example 1 is that the mass of TAEA is 90 mg, resulting in an adsorbent.

[0054] Example 4

[0055] The only difference from Example 1 is that the solvent in the impregnation step is replaced with methanol instead of ethanol.

[0056] Example 5

[0057] The difference from Example 1 is that the amine used is polyethyleneimine (PEI), with a mass of 60 mg, to obtain the adsorbent.

[0058] Example 6

[0059] The difference from Example 1 is only that the mass of TAEA is 45 mg, and the adsorbent is obtained.

[0060] Example 7

[0061] The difference from Example 1 is only that the mass of TAEA is 120 mg, and the adsorbent is obtained.

[0062] Example 8

[0063] The only difference from Example 1 is that the solvent in the impregnation step is replaced with methanol instead of ethanol, and the mass of TAEA is 30 mg, resulting in an adsorbent.

[0064] Example 9

[0065] The only difference from Example 1 is that the solvent in the impregnation step is replaced with acetone instead of ethanol.

[0066] Effect Example

[0067] X-ray powder diffraction test:

[0068] The MOF adsorbents prepared in Examples 1-9 and the activated MIL101 samples were subjected to X-ray powder diffraction (PXRD) tests. The PXRD data were obtained using Rigaku testing.

[0069] Experimental results: The MOF adsorbents prepared in Examples 1-9 are basically the same as the activated MIL101 samples, and the crystals are in good condition.

[0070] Scanning electron microscopy test:

[0071] The size and morphology of the samples were observed using a scanning electron microscope (SEM). Data were collected using a JSM-7800F Prime instrument at a test voltage of 2kV.

[0072] Experimental results: The samples prepared in Examples 1-9 were all regular octahedrons with similar sizes, maintaining the basic morphology of MIL101 (compared to the activated MIL101 material). The crystals retained their original morphology after impregnation, and impregnation had little impact on the crystal morphology.

[0073] Particle size distribution test:

[0074] Based on the scanning electron microscopy (SEM) results, statistical particle size fitting was used to obtain the particle size distribution of Examples 1-9 and the activated MIL101 material; Experimental results:

[0075] The adsorbent in Example 1 had a uniform morphology and particle size, with an average particle size of approximately 344.9 nm; the adsorbent in Example 2 had a uniform morphology and particle size, with an average particle size of approximately 331.4 nm.

[0076] The adsorbent in Example 3 had a uniform morphology and particle size, with an average particle size of approximately 347.5 nm.

[0077] The adsorbent in Example 4 had a uniform morphology and particle size, with an average particle size of approximately 337.3 nm.

[0078] The adsorbent in Example 5 had a uniform morphology and particle size, with an average particle size of approximately 347.1 nm.

[0079] The average particle size of the activated MIL101 material is approximately 342.1 nm.

[0080] Activation and adsorption tests of samples:

[0081] The samples from Examples 1-9 were transferred to adsorption sample tubes with an outer diameter of 9 mm. The sample tubes were then connected to a Quantachrome Flovac vacuum degassing station (USA). The tubes were first evacuated at 25°C for 2-3 hours until the vacuum level dropped to <500 mTorr. Then, the temperature was increased in stages by 15°C every 15 minutes until reaching 80°C for activation over 12 hours. The final vacuum level inside the sample tube should be maintained at <15 mTorr to obtain a completely degassed framework. After cooling to 25°C and backfilling with pure nitrogen, the sample was ready for the next gas adsorption test. The sample mass for each test was 20-50 mg.

[0082] The room temperature (25℃) adsorption-desorption isotherm of the sample was tested using a high-throughput surface area analyzer-SN88. The adsorption-desorption cycle test conditions were 25℃, 400 ppm carbon dioxide, and nitrogen as the carrier gas. The desorption conditions were 50℃ and nitrogen purging.

[0083] Experimental Results: The adsorption isotherms of Examples 1-3 and Examples 6-7 showed consistent trends. With increasing proportions of tris(2-aminoethyl)amine (TAEA) and MIL101 (Cr), the carbon dioxide adsorption capacity first increased and then decreased. At a carbon dioxide partial pressure of 400 ppm, the carbon dioxide adsorption value of Example 1 was 75.0 cm⁻¹. 3 g -1 The carbon dioxide adsorption value in Example 2 was 27 cm⁻¹. 3 g -1 The carbon dioxide adsorption value in Example 3 was 64.5 cm⁻¹. 3 g -1 The carbon dioxide adsorption value in Example 6 was 44.9 cm⁻¹. 3 g-1 The carbon dioxide adsorption value in Example 7 was 41.1 cm⁻¹. 3 g -1 .

[0084] The carbon dioxide adsorption value in Example 4 was 49.8 cm⁻¹. 3 g -1 The carbon dioxide adsorption value in Example 5 was 32.1 cm⁻¹. 3 g -1 The carbon dioxide adsorption value in Example 8 was 27.0 cm⁻¹. 3 g -1 The carbon dioxide adsorption value of Example 9 is approximately 0 cm⁻¹. 3 g -1 .

[0085] Cyclic stability test of adsorbent

[0086] The direct air capture carbon dioxide MOF adsorbent material prepared in Example 1 was subjected to adsorption tests 10 times. The experimental results showed that after ten adsorption activation cycles, the adsorption capacity of the adsorbent material in Example 1 remained above 90%.

[0087] Specific surface area and pore volume testing:

[0088] The testing instrument was an Autosorb-iQ-MP-AG BET gas adsorption specific surface area analyzer, and the testing conditions were 77 KN2. The specific surface area was calculated using the BET model. The pore size distribution was obtained by fitting the N2 at 77 K on carbon (slit / cylindr. pores, QSDFT adsorption branch) model, and the minimum fitting error of the pore size distribution was 1.024%.

[0089] Experimental results:

[0090] The specific surface area of ​​Example 1 is 840 m² / g, and the pore volume is 0.4137 cc / g.

[0091] The activated MIL101 material (unmodified) has a specific surface area of ​​3300 m² / g and a pore volume of 1.61 cc / g.

[0092] The above embodiments and effect tests have been compiled into Table 1 below.

[0093] Table 1

[0094]

[0095] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method of preparing a MOF material, characterized in that, Includes the following steps: The activated MIL101 material and polyamine ligand were impregnated in an ethanol solvent, and the ethanol solvent was removed to obtain the MOF material. The polyamine ligand is tris(2-aminoethyl)amine; the mass ratio of activated MIL101 material to polyamine ligand is 1:(1-1.5). The method for preparing the activated MIL101 material includes the following steps: soaking MIL101 in a solvent, centrifuging and washing, and drying to obtain the activated MIL101 material; the solvent for soaking is an amide solvent; the soaking temperature is 60-80℃; and the soaking time is 10-14 hours. The impregnation process involves dispersing the activated MIL101 material and the polyamine ligand in an ethanol solvent using ultrasound. The ultrasound is performed in two stages: first, the activated MIL101 material and the polyamine ligand are separately dispersed in the ethanol solvent; second, the dispersions of the activated MIL101 material and the polyamine ligand are mixed. The first ultrasound session lasts 5-20 minutes, and the second ultrasound session lasts 15-60 minutes. The preparation method of the MIL101 material includes the following steps: reacting chromium nitrate nonahydrate and terephthalic acid in deionized water to obtain the product MIL-101.

2. The method of claim 1, wherein the MOF material is prepared by the steps of: It meets one or more of the following conditions: (1) The mass ratio of the activated MIL101 material to the polyamine ligand is 1:1 or 1:1.5; (2) The mass-to-volume ratio of the activated MIL101 material to the ethanol solvent is (10-50): 1 g / L; (3) The duration of the first ultrasound is 5-15 minutes; the duration of the second ultrasound is 20 minutes, 30 minutes or 40 minutes; The operation of removing ethanol solvent described in (4) is to remove ethanol solvent at 40-60°C for 15-30 hours.

3. The method of producing a MOF material according to claim 2, wherein It meets one or more of the following conditions: (1) The mass-to-volume ratio of the activated MIL101 material to the ethanol solvent is (20-40): 1 g / L; (2) The duration of the first ultrasound is 10 minutes; The operation to remove the ethanol solvent described in (3) is to remove the ethanol solvent at 50°C for 20 hours.

4. The method for preparing MOF material as described in claim 2, characterized in that, (1) The mass-to-volume ratio of the activated MIL101 material to the ethanol solvent is 30:1 g / L; And / or, (2) remove ethanol solvent under a nitrogen atmosphere.

5. The method of claim 1, wherein the MOF material is prepared by the steps of: The preparation method of the activated MIL101 material satisfies one or more of the following conditions: (1) The solvent used for soaking is N,N-dimethylformamide; (2) In the soaking step, the mass-to-volume ratio of MIL101 to the soaking solvent is 10-50 g / L; (3) The soaking temperature is 70℃; (4) The soaking time is 12 hours; (5) The soaking is performed multiple times; (6) The centrifugal washing is performed sequentially with amide solvents and alcohol solvents; (7) The mass-to-volume ratio of the amount of MIL101 and the solvent used in the centrifugal washing is 10-50 g / L; (8) The centrifugal washing is performed using N,N-dimethylformamide; (9) The centrifugal washing is performed with methanol; (10) The centrifugal washing speed is 7000-9000 rpm; (11) The centrifugal washing time is 2-4 minutes; (12) The drying temperature is 60-80℃; The drying time described in (13) is 14-16 hours.

6. The method of claim 1, wherein the MOF material is prepared by, The preparation method of the activated MIL101 material satisfies conditions (1) and / or (2) below: (1) The centrifugal washing is performed with N,N-dimethylformamide, and the washing is performed 2-5 times a day for a total of 6-10 times; (2) The centrifugal washing is performed with methanol, and the washing is performed 2-5 times a day, for a total of 9-15 times.

7. The method of claim 1, wherein the MOF material is prepared by the steps of: The preparation method of the activated MIL101 material satisfies one or more of the following conditions: (1) The soaking is performed twice; (2) The centrifugal washing was performed using N,N-dimethylformamide and methanol, respectively; (3) The mass-to-volume ratio of the amount of MIL101 and the solvent used in the centrifugal washing is 30 g / L; (4) The centrifugal washing is performed with N,N-dimethylformamide, and the washing is performed 3 times a day for a total of 9 times; (5) The centrifugal washing is performed with methanol, and the washing is performed 3 times a day for a total of 9 times; (6) The centrifugal washing speed is 8000 rpm; (7) The centrifugal washing time is 3 minutes; (8) The drying temperature is 70°C; The drying time described in (9) is 15 hours.

8. The method for preparing MOF material as described in claim 1, characterized in that, The preparation method of the MIL101 material satisfies one or more of the following conditions: (1) The mass ratio of the deionized water to the chromium nitrate nonahydrate is (8-12):1; (2) The mass ratio of the terephthalic acid to the chromium nitrate nonahydrate is 1:(2-3); (3) In the preparation method of the MIL101 material, the reaction temperature is 180-220℃; The reaction time described in (4) is 14-18 hours.

9. The method for preparing MOF material as described in claim 8, characterized in that, The preparation method of the MIL101 material satisfies one or more of the following conditions: (1) The mass ratio of the deionized water to the chromium nitrate nonahydrate is (9-11):1; (2) The mass ratio of the terephthalic acid to the chromium nitrate nonahydrate is 1:2.4; (3) In the preparation method of the MIL101 material, the reaction temperature is 200℃; The reaction time described in (4) is 16 hours.

10. The method for preparing MOF material as described in claim 8, characterized in that, The mass ratio of the deionized water to the chromium nitrate nonahydrate is 10:

1.

11. A MOF material prepared by any one of the preparation methods of MOF material as described in any one of claims 1-10.

12. An adsorbent, characterized in that, It includes the MOF material as described in claim 11.

13. The application of the MOF material as described in claim 11 or the adsorbent as described in claim 12 in gas adsorption or gas storage.

14. The use of the MOF material as described in claim 11 or the adsorbent as described in claim 12 in the adsorption or storage of carbon dioxide.

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