Microporous metal organic framework material, preparation method thereof and rare gas separation method

Abstract

The invention discloses a microporous metal organic framework material, a preparation method and a rare gas separation method, and belongs to the technical field of chemical adsorption separation, the microporous metal organic framework material is constructed by coordination of divalent metal ions, heterocyclic dicarboxylic acid ligands and nitrogen-containing heterocyclic ligands; divalent metal ions and heterocyclic dicarboxylic acid ligands are coordinated to form a two-dimensional polymer, and nitrogen-containing heterocyclic ligands serve as pillared bodies and are coordinated with the two-dimensional polymer to form a three-dimensional frame structure. A microporous metal organic framework material is used as an adsorbent and is in contact with a rare gas mixture, so that high-polarity rare gas is recognized and captured, and separation and purification of the rare gas are achieved. According to the invention, by changing different ligands and functional group substituents thereof, precise regulation and control of a pore chemical electrostatic environment are realized, so that selective separation of rare gases such as xenon / krypton, helium / neon and the like is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical adsorption and separation, and relates to an adsorption material, in particular to a microporous metal organic framework material and a preparation method and a rare gas separation method. Background Art

[0002] In scientific research and industrial applications, rare gases are of great value and are widely used in electronics, lasers, aerospace, medical imaging, and cryogenic cooling. However, due to the extremely low content of rare gases in the air and their extremely similar physical properties, separation and purification face great challenges. At present, the industrial sources of xenon and krypton are mainly by-products of large-scale air separation processes. Based on the difference in their boiling points (xenon: -107.1°C, krypton: -153.2°C), they are mainly separated by deep-cold distillation processes. Helium and neon mainly come from air separation waste gas or natural gas. Currently, they are mainly separated and purified by liquid hydrogen condensation and liquid neon condensation, but the process flow is complicated and the safety is low. Therefore, the existing separation and purification technologies of rare gases generally have problems such as high energy consumption, complex processes, high costs, and high equipment investment. It is urgent to develop new low-energy rare gas separation methods.

[0003] Compared with traditional cryogenic distillation technology, adsorption separation technology has the advantages of low cost, low energy consumption, and simple operation process. In recent years, it has attracted much attention in the separation of rare gases. However, traditional adsorbents often have low selectivity and adsorption capacity. For example, although activated carbon can preferentially adsorb xenon, and the xenon adsorption capacity is 4mmol / g, the xenon / krypton separation selectivity is only 2-3 (Langmuir, 2012, 28, 11584-11589); the activated carbon published in patent application CN115676786A can preferentially adsorb neon and exclude helium, but it can only be achieved at low temperatures of 60-70K. Metal-organic framework materials have also attracted attention in the field of rare gas adsorption and separation due to their advantages such as high specific surface area and adjustable pore size structure. For example, patent application CN108727607A discloses a metal organic framework material made of Co metal and square acid for the adsorption and separation method of xenon / krypton, with a xenon / krypton separation selectivity of 36.4, but the xenon adsorption amount is less than 1 mmol / g; the adsorption amount of ZUL-530 for xenon is 3.1 mmol / g, and the xenon / krypton separation selectivity reaches 20.5, but the material has poor stability and is difficult to use in industry (J.Am.Chem.Soc, 2024, 146, 24956-24965).

[0004] As can be seen from the above, for the adsorption and separation of noble gases, the existing adsorbents still have the following problems: 1) low adsorption capacity or selectivity; 2) expensive synthetic raw materials and complicated preparation methods; 3) poor material stability and short service life; 4) few adsorbents can achieve helium / neon separation. Therefore, it is urgent to develop new adsorbent materials that are cheap, have high adsorption capacity, high selectivity and stability to achieve efficient separation of noble gases. Summary of the invention

[0005] In view of the defects of the prior art, the present invention provides a microporous metal organic framework material and a method for preparing and separating rare gases. The microporous metal organic framework material is used as an adsorption medium and is contacted with a rare gas mixture. The adsorption medium interacts with specific rare gas molecules to achieve selective identification and capture of the rare gas molecules, thereby achieving separation of the rare gas mixture.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a microporous metal organic framework material for rare gas separation: it is constructed by the coordination of divalent metal ions, heterocyclic dicarboxylic acid ligands and nitrogen-containing heterocyclic ligands; the divalent metal ions and heterocyclic dicarboxylic acid ligands are coordinated to form a two-dimensional polymer, and the nitrogen-containing heterocyclic ligands serve as pillar supports to form a three-dimensional framework structure by coordinating with the two-dimensional polymer.

[0008] Optionally, the divalent metal ion is Zn 2+ 、Ni 2+ 、Co 2+ , Cu 2+ , Mn 2+ Mg 2+ , Fe 2+ , Ca 2+ Any one or more of .

[0009] Optionally, the heterocyclic dicarboxylic acid ligand is Any one or both of .

[0010] Optionally, the nitrogen-containing heterocyclic ligand is Any one or more of, wherein R is any one of H, CH3, NH2, F, Cl, I, Br, OH, CN.

[0011] Optionally, the pore size of the microporous metal organic framework material is

[0012] In a second aspect, the present invention also provides a method for preparing the above-mentioned microporous metal organic framework material: water, N,N-dimethylformamide or a mixed solution of the two are added to divalent metal ions, heterocyclic dicarboxylic acid ligands and nitrogen-containing heterocyclic ligands, heated at 100-180°C for 24-72h, and the product is separated by filtration to obtain the microporous metal organic framework material.

[0013] In a third aspect, the present invention also provides a method for separating rare gases based on microporous metal-organic framework materials: the above-mentioned microporous metal-organic framework material is an adsorption medium, which is contacted with a rare gas mixture to achieve separation of the rare gas mixture.

[0014] Optionally, the rare gas mixture is a mixture of any two or more of xenon, krypton, helium, neon and argon; the rare gas mixture is a binary mixture or a ternary mixture, the volume ratio of each component in the binary mixture is 1:1-99, and the volume ratio of each component in the ternary mixture is 1:1-20:1-80.

[0015] Optionally, the contacting method is any one of fixed bed adsorption, fluidized bed adsorption, moving bed adsorption, and micro-packed fixed bed adsorption, preferably, fixed bed adsorption or micro-packed fixed bed adsorption; the operating temperature is 0-70°C, and the operating pressure is 0.2-10 bar.

[0016] Optionally, 3,5-pyrazoledicarboxylic acid, Zn 2+ The pore size of the microporous metal organic framework material constructed with 5-aminotetrazolyl is Xenon gas can be selectively captured from krypton gas to achieve separation of xenon / krypton mixed gas, and the purity of the obtained xenon and krypton gases is greater than 99.99%.

[0017] Optionally, 3,5-pyrazoledicarboxylic acid, Co 2+ The pore size of the microporous metal organic framework material constructed with 3,5-diamino-1,2,4-triazole is It can realize the separation of helium / neon mixed gas, the adsorption amount of neon is much higher than that of helium, and the purity of the separated helium and neon is greater than 99.95%.

[0018] Optionally, imidazole-4,5-dicarboxylic acid, Zn 2+ The pore size of the microporous metal organic framework material constructed with tetrazole is The adsorption capacity of xenon is much higher than that of krypton, and separation of xenon / krypton mixed gas is achieved. The purity of the separated xenon and krypton is greater than 99.8%.

[0019] Optionally, imidazole-4,5-dicarboxylic acid, Zn 2+ The pore size of the microporous metal organic framework material constructed with 2-aminopyrazine is Xenon gas can be selectively captured from krypton gas to achieve separation of xenon / krypton mixed gas, and the purity of the separated xenon and krypton gases is greater than 99.9%.

[0020] Optionally, 3,5-pyrazoledicarboxylic acid, Co 2+ The pore size of the microporous metal organic framework material constructed with 3,5-dimethyl-1,2,4-triazole is It can separate helium / neon mixed gas, and the adsorption capacity of neon is much higher than that of helium. The purity of separated helium and neon is greater than 99.9%.

[0021] Optionally, imidazole-4,5-dicarboxylic acid, Cu 2+ The pore size of the microporous metal organic framework material constructed with 4,4'-bipyrazole is It can separate xenon / krypton mixed gas, and the adsorption capacity of xenon is much higher than that of krypton. The purity of the separated xenon and krypton is greater than 99.8%.

[0022] The present invention forms a two-dimensional layer by first coordinating the metal with the carboxylic acid, and then connects the two-dimensional layer with the nitrogen-containing heterocyclic ring as a pillar ligand to form a three-dimensional structure. In addition, by changing the type of nitrogen-containing heterocyclic ligands, the pore size of the microporous metal organic framework material can be controlled first, so that it is closer to the kinetic diameter of the guest molecule to produce a greater interaction; secondly, by changing the functional group substituents on the nitrogen-containing heterocyclic ligands, the chemical environment in the pore can be changed, so that it produces a stronger interaction with gas molecules with greater polarity.

[0023] The beneficial effects of the present invention are:

[0024] 1. The raw materials of the microporous metal organic framework material of the present invention are easily available and the preparation is simple, and the adsorbent is easy to regenerate, has high water / thermal stability, and has a long service life, and has good industrial application prospects.

[0025] 2. The present invention can obtain high-purity xenon, krypton, helium and neon products according to industrial needs, with the purity reaching up to 99.99%.

[0026] 3. Compared with traditional adsorbents, the microporous metal-organic framework material of the present invention has the advantage of precise and adjustable interaction force with adsorbate molecules.

[0027] 4. Compared with the traditional low-temperature distillation technology in industry, the gas separation method of the present invention has outstanding advantages such as low energy consumption, easy operation and small equipment investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the adsorption isotherm of xenon and krypton at 25° C. for the microporous metal organic framework material of Example 1;

[0029] Figure 2This is the penetration curve of the microporous metal organic framework material of Example 1 to xenon and krypton (20 / 80, v / v).

[0030] Figure 3 is the adsorption isotherm of helium and neon of the microporous metal organic framework material of Example 3 at 0°C;

[0031] Figure 4 is the penetration curve of the microporous metal organic framework material of Example 3 to neon and helium (15 / 85, v / v);

[0032] Figure 5 is the adsorption isotherm of xenon and helium at 40° C. for the microporous metal organic framework material of Example 4;

[0033] Figure 6 is the penetration curve of the microporous metal organic framework material of Example 4 to xenon and krypton (20 / 80, v / v);

[0034] Figure 7 This is the adsorption isotherm of the microporous metal organic framework material of Example 7 for helium and neon at 25°C. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with specific embodiments.

[0036] Example 1

[0037] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 0.5 mmol Zn(NO3)2, 0.25 mmol 3,5-pyrazoledicarboxylic acid and 0.5 mmol 5-aminotetrazole are placed in a culture bottle, 7.5 mL water and 2.5 mL N,N-dimethylformamide are added, ultrasonicated at room temperature for 5 min, and then reacted at 100°C for 48 h, and the obtained microporous metal-organic framework material is subjected to gas adsorption.

[0038] The adsorption behavior of xenon and krypton by the activated microporous metal organic framework material of this example was tested at 25°C. The adsorption isotherms are shown in FIG. Figure 1 The adsorption capacity of xenon is 53.8 cm 3 / g, the adsorption capacity of krypton is only 19.5cm 3 / g.

[0039] The activated microporous metal organic framework material was filled into a 5 cm adsorption column. A 0.1 MPa xenon / krypton (20 / 80, v / v) mixed gas was passed into the adsorption column at 2 mL / min at 25°C. Krypton gas with a purity of 99.99% was obtained in the outflowing gas. When xenon gas penetrated, the adsorption was stopped. The penetration curve is shown in FIG. Figure 2 shown.

[0040] Example 2

[0041] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 1 mmol Zn(NO3)2, 0.5 mmol 3,5-pyrazoledicarboxylic acid and 1 mmol tetrazole are placed in a hydrothermal autoclave, 10 mL water and 4 mL N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 5 min, and then the reaction is performed at 120°C for 36 h to obtain the microporous metal-organic framework material.

[0042] Example 3

[0043] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 1 mmol Zn(NO3)2, 0.5 mmol imidazole-4,5-dicarboxylic acid and 1 mmol 3,5-diamino-1,2,4-triazole are placed in a hydrothermal autoclave, 10 mL water and 4 mL N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 10 min, and then the reaction is performed at 150°C for 48 h. The obtained microporous metal-organic framework material is subjected to a gas adsorption test.

[0044] The adsorption behavior of helium and neon on the activated microporous metal organic framework material was tested at 0°C. The adsorption isotherms are shown in Figure 3 As shown. The adsorption capacity of neon is 54.7cm 3 / g, the adsorption capacity of helium is only 26.7cm 3 / g.

[0045] The activated microporous metal organic framework material was loaded into a 5 cm adsorption column. A 0.1 MPa helium / neon (15 / 85, v / v) mixed gas was passed into the adsorption column at 2 mL / min at 0°C. Helium with a purity of 99.99% was obtained in the outflowing gas. When neon penetrated, the adsorption was stopped. The penetration curve is shown in FIG. Figure 4 shown.

[0046] Example 4

[0047] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 0.5 mmol Zn(NO3)2, 0.25 mmol 3,5-pyrazoledicarboxylic acid and 0.5 mmol 5-methyltetrazole are placed in a culture bottle, 10 mL water and 2.5 mL N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 10 min, and then the reaction is performed at 110°C for 72 h. The obtained microporous metal-organic framework material is subjected to a gas adsorption test.

[0048] The adsorption behavior of xenon and krypton on the activated microporous metal organic framework material was tested at 40°C. The adsorption isotherms are shown in Figure 2. Figure 5The adsorption capacity of xenon is 40.8 cm 3 / g, the adsorption capacity of krypton is only 14.1cm 3 / g.

[0049] The activated microporous metal organic framework material was filled into a 5 cm adsorption column. A 0.1 MPa xenon / krypton (20 / 80, v / v) mixed gas was passed into the adsorption column at 2 mL / min at 25°C. Krypton gas with a purity of 99.99% was obtained in the outflowing gas. When xenon gas penetrated, the adsorption was stopped. The penetration curve is shown in FIG. Figure 6 shown.

[0050] Example 5

[0051] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation, and the preparation method thereof is as follows: 1 mmol Co(NO3)2, 0.5 mmol imidazole-4,5-dicarboxylic acid and 1 mmol 3,5-dimethyl-1,2,4-triazole are placed in a hydrothermal autoclave, 15 mL of water and 5 mL of N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 10 min, and then the reaction is performed at 150°C for 48 h to obtain the microporous metal-organic framework material.

[0052] Example 6

[0053] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 1 mmol Cu(NO3)2, 1 mmol 3,5-pyrazoledicarboxylic acid and 1 mmol 1,2,3-triazole are placed in a hydrothermal autoclave, 5 mL methanol and 5 mL N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 10 min, and then the reaction is performed at 140°C for 48 h to obtain the microporous metal-organic framework material.

[0054] Example 7

[0055] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 1 mmol Ni(NO3)2, 0.5 mmol 3,5-pyrazoledicarboxylic acid and 1 mmol 1,2,3-triazole are placed in a hydrothermal autoclave, 10 mL water and 5 mL N,N-dimethylformamide are added, ultrasonic treatment is performed at room temperature for 5 min, the obtained solution is sealed, and the reaction is performed at 150°C for 72 h, and the obtained microporous metal-organic framework material is subjected to a gas adsorption test.

[0056] The adsorption behavior of helium and neon on the activated microporous metal organic framework material was measured at 25°C. The adsorption isotherms are shown in Figure 7 As shown. The adsorption capacity of neon is 52.6cm 3 / g, and the adsorption capacity of helium is only 13.2cm 3 / g.

[0057] Example 8

[0058] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 1 mmol Co(NO3)2, 0.5 mmol 2,5-pyrroledicarboxylic acid and 1 mmol 3,6-di(4-pyridyl)-1,2,4,5-tetrazine are placed in a culture bottle, 5 mL water and 5 mL N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 5 min, and then the reaction is performed at 100°C for 24 h to obtain a microporous metal-organic framework material.

[0059] Example 9

[0060] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 1 mmol Zn(NO3)2, 0.5 mmol 1,2,3-triazole-4,5-dicarboxylic acid and 1 mmol tetrazole are placed in a culture bottle, 7.5 mL water and 2.5 mL N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 5 min, and then the reaction is performed at 120°C for 24 h to obtain the microporous metal-organic framework material.

[0061] Example 10

[0062] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 1 mmol Ni(NO3)2, 0.5 mmol 3,5-pyridinedicarboxylic acid and 1 mmol 5-aminotetrazole are placed in a culture bottle, 10 mL water and 2.5 mL N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 10 min, and then the reaction is performed at 120°C for 24 h to obtain the microporous metal-organic framework material.

[0063] Embodiment 11

[0064] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 1 mmol Co(NO3)2, 0.5 mmol imidazole-4,5-dicarboxylic acid and 1 mmol 4,4'-bipyrazole are placed in a culture bottle, 10 mL of water and 5 mL of N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 5 minutes, and then the reaction is performed at 100°C for 24 hours to obtain a microporous metal-organic framework material.

[0065] Example 12

[0066] The present embodiment provides a microporous metal-organic framework material that can be used for rare gas separation. The preparation method thereof is as follows: 0.5 mmol Zn(NO3)2, 0.25 mmol 4,6-pyrimidinedicarboxylic acid and 0.5 mmol 5-methyltetrazole are placed in a culture bottle, 10 mL water and 5 mL N,N-dimethylformamide are added, ultrasonication is performed at room temperature for 5 min, and then the reaction is performed at 120°C for 24 h to obtain the microporous metal-organic framework material.

[0067] In the present invention, unless otherwise specified, the scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. In addition, the reagents, materials and operating procedures used herein are reagents, materials and conventional procedures widely used in the corresponding fields.

[0068] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A microporous metal organic framework material for rare gas separation, characterized in that: It is constructed by the coordination of divalent metal ions, heterocyclic dicarboxylic acid ligands and nitrogen-containing heterocyclic ligands; the divalent metal ions and heterocyclic dicarboxylic acid ligands coordinate to form a two-dimensional polymer, and the nitrogen-containing heterocyclic ligands serve as pillar supports to form a three-dimensional framework structure by coordinating with the two-dimensional polymer.

2. The microporous metal organic framework material according to claim 1, characterized in that: The divalent metal ion is Zn 2+ 、Ni 2+ 、Co 2+ , Cu 2+ , Mn 2+ Mg 2+ , Fe 2+ , Ca 2+ Any one or more of .

3. The microporous metal organic framework material according to claim 1, characterized in that: The heterocyclic dicarboxylic acid ligand is Any one or both of .

4. The microporous metal organic framework material according to claim 1, characterized in that: The nitrogen-containing heterocyclic ligand is Any one or more of, wherein R is any one of H, CH3, NH2, F, Cl, I, Br, OH, CN.

5. The microporous metal organic framework material according to claim 1, characterized in that: The pore size of the microporous metal organic framework material is 6. The method for preparing a microporous metal organic framework material according to any one of claims 1 to 5, characterized in that: Water, N,N-dimethylformamide or a mixed solution of the two are added to divalent metal ions, heterocyclic dicarboxylic acid ligands and nitrogen-containing heterocyclic ligands, and heated at 100-180° C. for 24-72 hours to obtain the microporous metal organic framework material.

7. A method for separating rare gases based on microporous metal-organic framework materials, characterized in that: The microporous metal organic framework material as claimed in any one of claims 1 to 5 is an adsorption medium, which is contacted with a rare gas mixture to achieve separation of the rare gas mixture.

8. The method for separating rare gases according to claim 7, characterized in that: The rare gas mixture is a mixture of any two or more of xenon, krypton, helium, neon and argon; The rare gas mixture is a binary mixture or a ternary mixture, the volume ratio of each component in the binary mixture is 1:1-99, and the volume ratio of each component in the ternary mixture is 1:1-20:1-80.

9. The method for separating rare gases according to claim 7, characterized in that: The contacting method is any one of fixed bed adsorption, fluidized bed adsorption, moving bed adsorption, and micro-filled fixed bed adsorption; The operating temperature is 0-70°C and the operating pressure is 0.2-10bar.

10. The method for separating rare gases according to claim 7, characterized in that: Composed of 3,5-pyrazoledicarboxylic acid, Zn 2+ and 5-aminotetrazole to construct microporous metal-organic framework materials for separation of xenon / krypton mixed gases; Alternatively, 3,5-pyrazoledicarboxylic acid, Co 2+ and 3,5-diamino-1,2,4-triazole to construct microporous metal-organic framework materials for separation of helium / neon mixed gases; Alternatively, imidazole-4,5-dicarboxylic acid, Zn 2+ Constructing microporous metal organic framework materials with tetrazole for separation of xenon / krypton mixed gas; Alternatively, imidazole-4,5-dicarboxylic acid, Zn 2+ and 2-aminopyrazine to construct microporous metal-organic framework materials for separation of xenon / krypton mixed gases; Alternatively, 3,5-pyrazoledicarboxylic acid, Co 2+ and 3,5-dimethyl-1,2,4-triazole to construct microporous metal-organic framework materials for separation of helium / neon mixed gases; Alternatively, imidazole-4,5-dicarboxylic acid, Cu 2+ and 4,4'-bipyrazole to construct microporous metal-organic framework materials for xenon / krypton mixed gas separation.

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