Metal organic framework material, preparation method and application thereof

Abstract

The application discloses a kind of metal organic framework materials and preparation method and application thereof, belong to chemical separation technical field.The preparation method of metal organic framework material provided in the application includes the following steps: with water and methanol as solvent, with 4,4 '-dipyridyl and malic acid as organic ligand, zinc source is added, and reaction is carried out, in the reaction process, oxygen atom on malic acid is connected with zinc ion on zinc source to form 2D layered network structure, 2D layered network structure is bridged by 4,4 '-dipyridyl to form 3D rigid network framework, after reaction, metal organic framework material is prepared.The metal organic framework prepared by the application has super strong capture effect and large storage space for acetylene molecules, and also has excellent separation effect on acetylene carbon dioxide mixed system, to achieve the purpose of high-purity, high-yield acetylene purification in acetylene carbon dioxide mixture.

Description

Technical Field

[0001] This invention relates to the field of chemical separation technology, and more specifically to a metal-organic framework material, its preparation method, and its application. Background Technology

[0002] In recent years, with the efficient utilization of natural gas and coal resources, acetylene (C2H2) has transformed from a fuel to a high-value feedstock for the production of various organic chemicals and polymers. During its production, carbon dioxide (CO2) inevitably coexists as an impurity, ranging from 3% to 50%, posing a challenge to its subsequent industrial utilization efficiency. CO2 removal is essential for producing high-purity (>99%) C2H2. However, due to the similar kinetic molecular size of the two molecules... The similar physical properties of C2H2 and CO2 (boiling points: C2H2, 189.3K; CO2, 194.7K) make C2H2 / CO2 separation one of the most difficult and challenging chemical separation processes. Traditional methods relying on cryogenic distillation or solvent extraction typically require enormous costs and energy consumption. To address this issue, adsorption separation technology using advanced adsorbents offers significant advantages such as low energy consumption, high product purity, simple process flow, and minimal scale-up effects, making it a promising candidate for industrial applications.

[0003] Traditional porous adsorbents, such as zeolite molecular sieves and activated carbon, typically exhibit low adsorption capacity and selectivity, making them unsuitable for industrial applications. As emerging crystalline porous materials, metal-organic frameworks (MOFs) or porous coordination polymers (PCPs) offer significant advantages in the separation of light hydrocarbon mixtures. Ideally, an ideal C2H2 / CO2 separation adsorbent should possess high adsorption capacity, selectivity, and moderate heat of adsorption. Furthermore, industrial parameters such as stability, cost-effectiveness, and scalability are also crucial. Currently, the trade-off between adsorption capacity and separation selectivity, economic efficiency, and the achievement of large-scale industrial production remain significant challenges in MOFs used for C2H2 / CO2 mixture separation. Therefore, finding highly efficient adsorbents suitable for industrial applications remains a challenge. Summary of the Invention

[0004] To address the above problems, this invention provides a metal-organic framework (MOF) material, its preparation method, and its applications. Using inexpensive and widely available malic acid as the organic ligand and 4,4'-bipyridine as the pillar, MOFs coordinate with transition metal nodes to participate in the architecture, forming a high-density porous cage structure and a framework surface environment with a strong negative electrostatic potential. MOFs can be scaled up for large-scale industrial production. The prepared MOFs exhibit superior trapping ability and large storage space for acetylene molecules, while also demonstrating excellent separation performance in acetylene-carbon dioxide mixtures, achieving high-purity and high-yield purification of acetylene from these mixtures. Furthermore, the low synthesis cost and the ability to synthesize in large quantities make it a promising candidate for practical industrial pressure swing adsorption (PSA) applications.

[0005] The first objective of this invention is to provide a method for preparing a metal-organic framework material, comprising the following steps:

[0006] Using water and methanol as solvents, and 4,4'-bipyridine and malic acid as organic ligands, a zinc source was added to initiate a reaction. During the reaction, oxygen atoms on the malic acid bonded to zinc ions on the zinc source, forming a 2D layered network structure. These 2D layered network structures were then bridged by 4,4'-bipyridine to form a 3D rigid network framework. After the reaction, a metal-organic framework material was prepared. The cavity size of the 3D rigid network framework was 0.85 × 0.6 × 0.62 nm. 3 The aperture of the connecting cavities is 0.3 nm × 0.39 nm, and the pore volume is 0.1–0.2 cm³. 3 / g, porosity 30-40%, specific surface area 150-300m² 2 / g.

[0007] In a preferred embodiment of the present invention, the molar ratio of zinc source to 4,4'-bipyridine is 4 to 5:3. For example, the molar ratio of zinc source to 4,4'-bipyridine is 4:3, 4.2:3, 4.4:3, 4.6:3, 4.8:3, 5:3, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0008] In a preferred embodiment of the present invention, the molar ratio of 4,4'-bipyridine to malic acid is 4:3 to 4, for example, the molar ratio of 4,4'-bipyridine to malic acid is 4:3, 4:3.2, 4:3.4, 4:3.6, 4:3.8, 4:4, etc., but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable.

[0009] In a preferred embodiment of the present invention, the reaction temperature is 120℃~150℃ and the reaction time is 40h~48h. For example, the reaction temperature is 120℃, 125℃, 130℃, 135℃, 140℃, 145℃, 150℃, etc., and the reaction time is 40h, 41h, 42h, 43h, 44h, 45h, 46h, 47h, 48h, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0010] In a preferred embodiment of the present invention, the volume ratio of water to methanol is 1:1 to 2, for example, the volume ratio of water to methanol is 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, or 1:2.

[0011] The ratio of zinc source to water is 2.4 mmol to 3 mmol: 5 ml. For example, the ratio of zinc source to water is 2.4 mmol: 5 ml, 2.5 mmol: 5 ml, 2.6 mmol: 5 ml, 2.7 mmol: 5 ml, 2.8 mmol: 5 ml, 2.9 mmol: 5 ml, 3 mmol: 5 ml, etc., but it is not limited to the values ​​listed. Other unlisted values ​​within the above range are also applicable.

[0012] A second objective of this invention is to provide a metal-organic framework material prepared by the above-described preparation method.

[0013] A third objective of this invention is to provide the application of the aforementioned metal-organic framework material as an adsorbent, wherein the metal-organic framework material is used as an adsorbent to contact a gas mixture containing acetylene and carbon dioxide for adsorption and separation.

[0014] In a preferred embodiment of the present invention, the volume percentage of acetylene in the gas mixture is 1% to 99%, with the remainder being carbon dioxide. The volume percentage of acetylene is 1%, 11%, 21%, 31%, 41%, 51%, 61%, 71%, 81%, 91%, 99%, etc., but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0015] In a preferred embodiment of the present invention, the adsorption separation temperature is -50℃ to 100℃, and the adsorption pressure is 0 bar to 10 bar. For example, the adsorption separation temperature is -50℃, 0℃, 50℃, 100℃, etc., and the adsorption pressure is 0 bar, 1 bar, 2 bar, 3 bar, 4 bar, 5 bar, 6 bar, 7 bar, 8 bar, 9 bar, 10 bar, etc., but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0016] In a preferred embodiment of the present invention, the contact method is any one of fixed bed adsorption, fluidized bed adsorption, or moving bed adsorption.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) This invention utilizes inexpensive and widely available malic acid as an organic ligand and 4,4'-bipyridine as a pillar, coordinating with transition metal nodes to participate in the architecture. This self-assembly forms a metal-organic framework (MOF) adsorbent with a high-density porous cage structure and a strong negative electrostatic potential framework surface environment. It exhibits superior capture and storage capacity for acetylene molecules, while also demonstrating excellent separation performance in acetylene-carbon dioxide mixed systems, achieving the goal of purifying high-purity acetylene from carbon dioxide. The MOF constructed in this invention possesses a dense porous cage structure, providing greater space for gas storage. Simultaneously, the internal surface of the pores is distributed with a large number of negatively charged oxygen atoms, which generate a strong affinity with the positively charged hydrogen atoms at both ends of the acetylene molecule and repel the negatively charged oxygen atoms at both ends of the carbon dioxide molecule, thereby achieving high separation selectivity for acetylene / carbon dioxide.

[0019] (2) The metal-organic framework material prepared by the present invention has the following characteristics: efficient capture of acetylene from acetylene-carbon dioxide mixture, excellent dynamic breakthrough performance stability, material recyclability and solvent stability, good thermal stability, and considerable economic benefits.

[0020] (3) The metal-organic framework material prepared by this invention has achieved the transformation from gram-level synthesis to kilogram-level synthesis through the optimization of synthesis conditions. At the same time, the kilogram-level synthesized sample still maintains excellent adsorption performance for C2H2 / CO2 mixed gas, excellent dynamic breakthrough performance stability, material recyclability and solvent stability, good thermal stability, and considerable economic benefits. It is expected to be a potential physical adsorbent in the fields of high-efficiency and low-energy-consumption pressure swing adsorption and other industrial adsorption separation technologies, and realize the replacement of traditional energy-intensive technologies such as solvent extraction or low-temperature distillation for the separation of acetylene and carbon dioxide in industry. Attached Figure Description

[0021] Figure 1 This is a physical image of the Zn-bpy-DLmal material prepared in Example 1 of the present invention.

[0022] Figure 2 This is a magnified image of the synthesized Zn-bpy-DLmal material prepared in Example 1 of this invention.

[0023] Figure 3 This is a process route diagram for the Zn-bpy-DLmal material prepared in Example 1 of the present invention.

[0024] Figure 4 This is a physical image of the Zn-bpy-fum material prepared in Comparative Example 1 of this invention.

[0025] Figure 5 The diagram shows the structure of the Zn-bpy-DLmal material prepared in Example 1 of this invention, where a is a three-dimensional structure diagram, b is a YZ plane structure diagram, and c is an XZ plane structure diagram.

[0026] Figure 6 The diagram shows the structure of the Zn-bpy-fum material prepared in Comparative Example 1 of this invention, where a is the XZ plane structure diagram and b is the XY plane structure diagram.

[0027] Figure 7 The images show X-ray diffraction patterns of the Zn-bpy-DLmal material prepared in Example 1 of this invention. In the image, a is a comparison of X-ray diffraction patterns of the Zn-bpy-DLmal material in different states, and b is an X-ray diffraction pattern after immersion in different organic solutions.

[0028] Figure 8 The thermogravimetric curve of the Zn-bpy-DLmal material prepared in Example 1 of this invention is shown.

[0029] Figure 9 The figure shows the CO2 adsorption isotherm of the Zn-bpy-DLmal material prepared in Example 1 of this invention at 195 K. The inset is the BET plot of the Zn-bpy-DLmal material prepared in Example 1.

[0030] Figure 10 The figure shows the CO2 adsorption isotherm of the Zn-bpy-fum material prepared in Comparative Example 1 of this invention at 195 K, wherein the inset is the BET plot of the Zn-bpy-DLmal material prepared in Comparative Example 1.

[0031] Figure 11 The adsorption isotherms of acetylene and carbon dioxide on the Zn-bpy-DLmal material prepared in Example 1 of this invention at 298 K are shown.

[0032] Figure 12 The adsorption isotherms of acetylene and carbon dioxide at 298 K for the Zn-bpy-fum material prepared in Comparative Example 1 of this invention are shown.

[0033] Figure 13 The kinetic adsorption curves of the Zn-bpy-DLmal material prepared in Example 1 of this invention under 298K conditions show the changes in the adsorption capacity of acetylene and carbon dioxide with time and pressure.

[0034] Figure 14Dynamic breakthrough curves of the Zn-bpy-DLmal material prepared in Example 1 of this invention at different flow rates of acetylene / carbon dioxide mixed gas components under 298K conditions.

[0035] Figure 15 The cyclic dynamic breakthrough curve of the Zn-bpy-DLmal material prepared in Example 1 of this invention under 298K conditions for the acetylene / carbon dioxide mixed gas components.

[0036] Figure 16 The curve of acetylene desorption after dynamic penetration of the Zn-bpy-DLmal material prepared in Example 3 of the present invention at 298K is shown.

[0037] Figure 17 The adsorption isotherms of acetylene and carbon dioxide on a kilogram-scale synthetic sample of Zn-bpy-DLmal material prepared in Example 3 of this invention at 298 K.

[0038] Figure 18 The dynamic breakthrough curve of a kilogram-scale synthetic sample of Zn-bpy-DLmal material prepared in Example 3 of this invention under acetylene / carbon dioxide mixed gas components (volume ratio 1:1, flow rate 2.0 mL / min) at 298 K.

[0039] Figure 19 The dynamic breakthrough curve of the Zn-bpy-fum material prepared in Comparative Example 1 of this invention under acetylene / carbon dioxide mixed gas components at 298 K.

[0040] Figure 20 The curves show the dynamic acetylene desorption process of the Zn-bpy-fum material prepared in Comparative Example 1 of this invention after penetration of the acetylene / carbon dioxide mixed gas component at 298K. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example 1

[0043] A method for preparing a metal-organic framework material includes the following steps:

[0044] 2.4 mmol of zinc acetate dihydrate was dissolved in 5 mL of ultrapure water, and 1.8 mmol of 4,4'-bipyridine and 1.8 mmol of DL-malic acid were dissolved in 5 mL of methanol. After complete dissolution, the two mixed solutions were transferred to a polytetrafluoroethylene reactor and stirred at room temperature for 1 h to ensure thorough mixing. The reactor was then placed in an oven at 140 °C for 48 h, and cooled to room temperature for 10 h after the reaction. The resulting white crystalline sample is the Zn-bpy-DLmal crystalline sample, as shown in the image below. Figure 1 As shown.

[0045] Example 2

[0046] A method for preparing a metal-organic framework material includes the following steps:

[0047] 24 mmol of zinc acetate dihydrate was dissolved in 50 mL of ultrapure water, and 18 mmol of 4,4'-bipyridine and 18 mmol of malic acid were dissolved in 50 mL of methanol. After complete dissolution, the two mixed solutions were stirred at room temperature for 1 h to achieve thorough mixing, and then refluxed at 120 °C for 48 h. The resulting slurry was collected by vacuum filtration, and the obtained solid was dried at 60 °C to obtain the Zn-bpy-DLmal powder sample.

[0048] Example 3

[0049] A method for preparing a metal-organic framework material includes the following steps:

[0050] 240 mmol of zinc acetate dihydrate was dissolved in 500 mL of ultrapure water, and 180 mmol of 4,4'-bipyridine and 180 mmol of malic acid were dissolved in 500 mL of methanol. After complete dissolution, the two mixed solutions were stirred at room temperature for 1 h to achieve thorough mixing, and then refluxed at 120 °C for 48 h. The resulting slurry was collected by vacuum filtration, and the obtained solid was dried at 60 °C to obtain the Zn-bpy-DLmal powder sample. A picture of the actual sample is shown below. Figure 2 As shown, the preparation process is as follows: Figure 3 As shown.

[0051] Example 4

[0052] A method for preparing a metal-organic framework material includes the following steps:

[0053] 30 mmol of zinc acetate dihydrate was dissolved in 50 mL of ultrapure water, and 18 mmol of 4,4'-bipyridine and 18 mmol of malic acid were dissolved in 100 mL of methanol. After complete dissolution, the two mixed solutions were stirred at room temperature for 1 h to achieve thorough mixing, and then refluxed at 150 °C for 40 h. The resulting slurry was collected by vacuum filtration, and the obtained solid was dried at 60 °C to obtain the Zn-bpy-DLmal powder sample.

[0054] Example 5

[0055] A method for preparing a metal-organic framework material includes the following steps:

[0056] 27 mmol of zinc acetate dihydrate was dissolved in 50 mL of ultrapure water, and 18 mmol of 4,4'-bipyridine and 18 mmol of malic acid were dissolved in 75 mL of methanol. After complete dissolution, the two mixed solutions were stirred at room temperature for 1 h to achieve thorough mixing, and then refluxed at 130 °C for 44 h. The resulting slurry was collected by vacuum filtration, and the obtained solid was dried at 60 °C to obtain the Zn-bpy-DLmal powder sample.

[0057] Comparative Example 1

[0058] In this comparative example, a metal-organic framework was prepared using fumaric acid as a ligand. The preparation method includes the following steps:

[0059] 2.4 mmol of zinc acetate dihydrate was dissolved in 5 mL of ultrapure water, and 1.8 mmol of 4,4'-bipyridine and 1.8 mmol of fumaric acid were dissolved in 5 mL of methanol. After complete dissolution, the two mixed solutions were transferred to a polytetrafluoroethylene reactor and stirred at room temperature for 1 h to ensure thorough mixing. The reactor was then placed in an oven at 140 °C for 48 h, and cooled to room temperature for 10 h after the reaction. The resulting white powder sample is the Zn-bpy-fum powder sample. A photograph of the sample is shown in Figure 4.

[0060] In metal-organic frameworks (MOFs), the carboxyl and hydroxyl oxygen atoms on the malic acid ligand are ionicly bonded to zinc to form a regular 2D layered network structure. Adjacent 2D layered network structures are further bridged by 4,4'-bipyridine. After the malic acid and zinc ions are ionicly bonded, a vacancy is created by the six-coordinated zinc ion, which continues to coordinate with the nitrogen atom in the 4,4'-bipyridine to form a stable structure. This self-assembly assembly forms a regular, highly stable, dense, rigid 3D network framework. The structure of this Zn-bpy-DLmal MOF is shown below. Figure 5 As shown, the cavity size of the 3D rigid network framework is 0.85 × 0.6 × 0.62 nm. 3 The aperture of the connecting cavities is 0.3 nm × 0.39 nm, and the pore volume is 0.1–0.2 cm³. 3 / g, porosity 30-40%, specific surface area 150-300m² 2 / g.

[0061] The structure of the metal-organic framework material Zn-bpy-fum in Comparative Example 1 is as follows: Figure 6 As shown, the one-dimensional through-hole size of the 3D flexible interpenetrating network framework is 0.3 × 0.42 nm.3 Pore ​​capacity 0.05–0.1 cm³ 3 / g, specific surface area of ​​100-200m² 2 / g.

[0062] Figure 7 The X-ray diffraction pattern is shown for testing the phase purity and organic solution immersion stability of the Zn-bpy-DLmal material in Example 1 of this invention. Figure 7 In the text 'a', 'Activated' refers to the activation treatment of the Zn-bpy-DLmal material prepared in Example 1, 'As-synthesized' refers to the Zn-bpy-DLmal material synthesized in Example 1, and 'Simulated' refers to the XRD simulation of the obtained crystal structure information (cif file) using Materials Studio 2023 software. The Zn-bpy-DLmal material synthesized in Example 1 exhibits extremely high diffraction peak intensities, indicating high crystallinity and phase purity. Furthermore, after soaking in organic and aqueous solutions for one week, as... Figure 7 As shown in b, the X-ray diffraction peaks and positions remained essentially unchanged, further verifying the material's stability in organic solutions and water.

[0063] It should be noted that the specific activation process is as follows: the Zn-bpy-DLmal material is washed three times with methanol solution and dried overnight at 60°C under vacuum for 12 hours.

[0064] Figure 8 This is a thermogravimetric curve of the Zn-bpy-DLmal material from Embodiment 1 of the present invention. Figure 8 As shown, the Zn-bpy-DLmal material synthesized in Example 1 exhibits significant weight loss at 400℃, indicating the collapse of the framework structure, and the material's thermal stability reaches up to 400℃.

[0065] When conducting gas adsorption tests, the Zn-bpy-DLmal and Zn-bpy-fum materials need to be activated to remove guest molecules from the materials. The activation method is the same as the activation steps described above.

[0066] Figure 9 This is the CO2 adsorption isotherm at 195 K for the Zn-bpy-DLmal material of Example 1 of this invention. Figure 9 As shown, the Zn-bpy-DLmal material synthesized in Example 1 has a specific surface area of ​​162.7 m² / s² based on CO₂ adsorption at 195 K. 2 / g, pore volume is 0.116cm³ 3 / g.

[0067] Figure 10This is the CO2 adsorption isotherm at 195°C for the Zn-bpy-fum material in Comparative Example 1 of this invention. Figure 10 As shown, the Zn-bpy-fum material synthesized in Comparative Example 1 has a specific surface area of ​​145.1 m² / s² based on CO2 adsorption at 195 K. 2 / g, pore volume is 0.089cm³ 3 / g.

[0068] Figure 11 The adsorption isotherms of acetylene and carbon dioxide for the Zn-bpy-DLmal material of Example 1 of this invention at 298 K are shown below. Figure 11 As shown, under 298K conditions, the Zn-bpy-DLmal material synthesized in Example 1 adsorbed acetylene and carbon dioxide at capacities of 3.1 mmol / g and 1.9 mmol / g, respectively.

[0069] Figure 12 The adsorption isotherms of the Zn-bpy-fum material of Comparative Example 1 of this invention for acetylene and carbon dioxide at 298 K are shown below. Figure 12 As shown, under 298 K conditions, the Zn-bpy-fum material synthesized in Comparative Example 1 had an adsorption capacity of 1.9 mmol / g for acetylene and 0.4 mmol / g for carbon dioxide, and exhibited a significant "gate opening phenomenon," which is unfavorable for the separation of mixed gases.

[0070] Figure 13 This is the kinetic adsorption curve of the Zn-bpy-DLmal material of Example 1 of the present invention, showing the adsorption capacity of acetylene and carbon dioxide over time at 298 K (equilibrium pressure 500 mbar). Figure 13 As shown, acetylene and carbon dioxide both reached adsorption equilibrium at 10 min, but the adsorption amounts differed significantly, being 3.18 mmol / g and 1.95 mmol / g, respectively.

[0071] The metal-organic framework material Zn-bpy-DLmal obtained in Example 1 was packed into a fixed-bed adsorption column with an inner diameter of 4.6 mm and a length of 20 cm. At 298 K and 1 bar, an acetylene / carbon dioxide (50:50) mixture was flowed through the fixed-bed adsorption column packed with Zn-bpy-DLmal at a fixed flow rate of 2.0, 5.0, or 10.0 mL / min. The carbon dioxide component preferentially penetrated the bed, and high-purity carbon dioxide gas (>99.9%) was obtained at the tail end of the adsorption column. Adsorption was stopped when the adsorption column was completely penetrated. The adsorption column was regenerated by purging with helium at 100 °C, yielding high-purity acetylene gas (≥99%) during regeneration; alternatively, desorption regeneration was performed using a vacuum pump at 100 °C with a vacuum degree of 0.05 bar.

[0072] Figure 14 The dynamic breakthrough curves of the Zn-bpy-DLmal material prepared in Example 1 of this invention at 298 K are shown for three different flow rates (2.0 mL / min, 5.0 mL / min, and 10.0 mL / min) and a volume ratio of 1:1 acetylene / carbon dioxide mixed gas components. Figure 14 As shown, acetylene and carbon dioxide have distinct separation operating ranges, and exhibit excellent separation performance at all three flow rates.

[0073] Figure 15 The dynamic breakthrough curve of the Zn-bpy-DLmal material prepared in Example 1 of this invention under cyclic conditions of 1:1 volume ratio acetylene / carbon dioxide mixed gas at a flow rate of 2.0 mL / min at 298 K is shown below. Figure 11 As shown, the breakthrough time interval of acetylene-carbon dioxide did not decrease significantly in the five cycles, maintaining good cycle stability.

[0074] Figure 16 The image shows the acetylene desorption process curve of the Zn-bpy-DLmal material prepared in Example 1 of this invention after dynamic breakthrough at a flow rate of 2.0 mL / min with a 1:1 volume ratio acetylene / carbon dioxide mixed gas component at 298 K. Figure 16 As shown, when purged and desorbed with helium at a rate of 10 mL / min, carbon dioxide was first purged at approximately 11.3 min / g, followed by acetylene product with a purity ≥99%.

[0075] Figure 17 The adsorption isotherms of acetylene and carbon dioxide on a kilogram-scale synthetic sample of the Zn-bpy-DLmal material prepared in Example 3 of this invention at 298 K are shown below. Figure 17 As shown, the adsorption capacity of the synthesized Zn-bpy-DLmal material for acetylene and carbon dioxide was not significantly reduced by scale-up.

[0076] Figure 18 The dynamic breakthrough curve of a kilogram-scale synthetic sample of Zn-bpy-DLmal material prepared in Example 3 of this invention, with a volume ratio of 1:1 acetylene / carbon dioxide mixed gas component at a flow rate of 2.0 mL / min under 298 K conditions, is shown below. Figure 18 As shown, the synthesized Zn-bpy-DLmal material exhibits a clear separation range for acetylene and carbon dioxide, maintaining excellent separation performance.

[0077] The metal-organic framework material Zn-bpy-fum obtained in Comparative Example 1 was packed into a fixed-bed adsorption column with an inner diameter of 4.6 mm and a length of 20 cm. At 298 K and 1 bar, an acetylene / carbon dioxide (50:50) mixture was flowed through the fixed-bed adsorption column packed with Zn-bpy-fum at a fixed flow rate of 2.0 mL / min. The carbon dioxide component preferentially penetrated the bed, and high-purity carbon dioxide gas (>99%) was obtained at the tail end of the adsorption column. Adsorption was stopped when the adsorption column was completely penetrated. The adsorption column was regenerated by purging with helium at 100 °C, yielding acetylene gas (≥90%) during regeneration; alternatively, desorption regeneration was performed using a vacuum pump at 100 °C with a vacuum degree of 0.05 bar.

[0078] Figure 19 The image shows the dynamic breakthrough curve of the Zn-bpy-fum material in Comparative Example 1 of this invention at 298 K with a flow rate of 2.0 mL / min and a volume ratio of 1:1 for an acetylene / carbon dioxide mixed gas. Figure 19 As shown, acetylene and carbon dioxide have a relatively short separation range, and the purity of the resulting gas is low.

[0079] Figure 20 The image shows the acetylene desorption process curve of the Zn-bpy-fum material in Comparative Example 1 of this invention after dynamic breakthrough at a flow rate of 2.0 mL / min with a volume ratio of 1:1 acetylene / carbon dioxide mixed gas component at 298 K. Figure 20 As shown, when purged with helium at a rate of 5 mL / min, carbon dioxide was initially removed at approximately 10.2 min / g, followed by an acetylene product with a purity ≥90%, which was lower than the concentration of the product obtained under the same conditions from Zn-bpy-DLmal prepared in Example 1. This is because the Zn-bpy-fum material has a flexible, double-interpenetrating structure, which exhibits significant co-adsorption during dynamic separation, thus affecting the concentration of the obtained product.

[0080] It should be noted that the preparation method described in Example 1 synthesized a crystalline sample, while the preparation methods in Examples 2 and 3 synthesized a powder sample. The performance parameters of the crystalline and powder samples are quite similar, and the performance differences are negligible.

[0081] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0082] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a metal-organic framework material, characterized in that, Includes the following steps: Using water and methanol as solvents, and 4,4'-bipyridine and DL-malic acid as organic ligands, a zinc source was added to carry out the reaction. During the reaction, the oxygen atoms on DL-malic acid are connected to the zinc ions on the zinc source to form a 2D layered network structure. The 2D layered network structures are bridged by 4,4'-bipyridine to form a 3D rigid network framework. After the reaction is completed, a metal-organic framework material is prepared.

2. The method for preparing a metal-organic framework material according to claim 1, characterized in that, The molar ratio of zinc source to 4,4'-bipyridine is 4~5:

3.

3. The method for preparing a metal-organic framework material according to claim 1, characterized in that, The molar ratio of zinc source to DL-malic acid is 4~5:

3.

4. The method for preparing a metal-organic framework material according to claim 1, characterized in that, The reaction temperature is 120℃~150℃, and the reaction time is 40h~48h.

5. The method for preparing a metal-organic framework material according to claim 1, characterized in that, The volume ratio of water to methanol was 1:1 to 2, and the ratio of zinc source to water was 2.4 mmol to 3 mmol: 5 ml.

6. A metal-organic framework material prepared by the preparation method according to any one of claims 1-5.

7. The application of the metal-organic framework material of claim 6 as an adsorbent, characterized in that, Metal-organic framework materials are used as adsorbents to contact a gas mixture containing acetylene and carbon dioxide for adsorption and separation.

8. The application of the metal-organic framework material according to claim 7 as an adsorbent, characterized in that, In the gas mixture, the volume percentage of acetylene is 1% to 99%, and the remainder is carbon dioxide, totaling 100%.

9. The application of the metal-organic framework material according to claim 7 as an adsorbent, characterized in that, The adsorption separation temperature is -50℃ to 100℃, and the adsorption pressure is 0 bar to 10 bar.

10. The application of the metal-organic framework material according to claim 7 as an adsorbent, characterized in that, The contact method can be any one of fixed bed adsorption, fluidized bed adsorption, or moving bed adsorption.

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