Mixed matrix membranes, methods of making and using the same

Abstract

The application relates to the field of membrane separation technology, and particularly relates to a mixed matrix membrane and a preparation method and application thereof. The mixed matrix membrane comprises a polymer matrix and a filler dispersed in the polymer matrix; the filler comprises a MOF material and a MA composite amine loaded on the MOF material; the MA composite amine is selected from one or more of ethanolamine, methyl monoethanolamine, diethanolamine, N-methyl diethanolamine (MDEA), diisopropylamine, hydroxyethyl ethylenediamine and 2-amino-2-methyl-1-propanol. The mixed matrix membrane has high selectivity and high permeability, and is suitable for large-scale continuous preparation.

Description

Technical Field

[0001] This invention relates to the field of membrane separation technology, specifically to a mixed matrix membrane, its preparation method, and its application. Background Technology

[0002] Carbon dioxide capture technologies mainly include absorption, adsorption, membrane methods, and cryogenic separation. Among these, membrane separation technology has received widespread attention from researchers. Membrane separation is simple in process, requires low equipment investment, consumes little energy, is flexible in operation, and occupies little space, making it a promising technology for CO2 capture from flue gas. In recent years, countries such as the United States, Germany, and Norway have been actively conducting research on membrane technologies for CO2 capture from flue gas.

[0003] The goal of CO2 capture from combustion exhaust gas is to achieve a CO2 purity greater than 95 vol%, a recovery rate greater than 90%, and an increase in power plant generation costs not exceeding 35%. Currently, membrane technologies for capturing CO2 from power plant flue gas are insufficient to meet the techno-economic requirements of industrial applications. This is related to many factors, such as the CO2 / N2 separation performance of the membrane, the design of the membrane module, and the membrane process. Existing commercial CO2 separation membranes are all polymer membranes with CO2 permeation rates of 50-100 GPU and CO2 / N2 separation factors of 20-30. To accelerate the industrialization of membrane technologies for CO2 capture from flue gas, numerous research institutions and companies both domestically and internationally have developed various high-performance CO2 separation membranes and membrane process technologies. The Membrane Technology Research Center (MTR) in the United States and the GKSS Research Center in Germany have respectively prepared PolarisTM (CO2 permeation rate of 1000-2000 GPU, CO2 / N2 separation factor of approximately 50) and Polyactive flat-sheet composite membrane (CO2 permeation rate close to 1000 GPU, CO2 / N2 separation factor of approximately 55) using polyoxyethylene polymer membrane materials. MTR conducted a pilot-scale (1 ton / day) test of capturing CO2 from flue gas using the large-scale prepared PolarisTM flat-sheet composite membrane at the National Carbon Capture Center in the United States. Research institutions such as Ohio State University and the Norwegian University of Science and Technology have developed a series of CO2 separation membranes containing functional groups using polymer membrane materials rich in functional groups such as amine groups, such as polyvinylamine (PVAm), polyethyleneimine (PEI), and polyallylamine (PAAm). They have prepared flat-sheet membrane modules and hollow fiber membrane modules respectively and conducted real flue gas tests.

[0004] Environmentally friendly and energy-efficient membrane separation technology is currently a hot research topic in gas separation technology. Among the current membrane material development, MOF hybrid matrix membranes have attracted widespread attention due to their unique advantages. Numerous studies on MOF hybrid matrix membranes have been reported. To further obtain high-performance membrane materials, modifying MOF materials is a very effective method. However, chemical modification methods are difficult to control, and the original properties of the MOF material are easily destroyed during the modification process. Compared with chemical modification methods, combining other functional materials with MOF materials to prepare composite materials, and designing appropriate composite methods, can maximize the advantages of both materials. This allows for the production of novel functionalized MOF composite materials for specific applications. Using functionalized MOF composite materials as additives to prepare hybrid matrix membranes can yield novel membrane materials.

[0005] This invention aims to improve the separation performance of CO2 separation membranes and provides a novel high-efficiency MOF mixed matrix membrane based on the coordination effect of MA complex amines and its preparation method. Summary of the Invention

[0006] The purpose of this invention is to overcome the technical problem of low CO2 separation efficiency caused by the low permeability and low selectivity of the separation membrane material in existing membrane separation technologies, which makes it difficult to realize large-scale industrial applications of membrane separation CO2 capture technology. This invention provides a hybrid matrix membrane, its preparation method, and its application. The hybrid matrix membrane of this invention combines high selectivity and high permeability, making it suitable for large-scale continuous preparation.

[0007] To achieve the above objectives, a first aspect of the present invention provides a hybrid matrix membrane comprising a polymer matrix and fillers dispersed in the polymer matrix;

[0008] The filler includes MOF material and MA composite amine supported on MOF material;

[0009] The MA complex amine is selected from one or more of ethanolamine (MEA), methyl monoethanolamine (MMEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), diisopropylamine (DIPA), hydroxyethyl ethylenediamine (AEEA), and 2-amino-2-methyl-1-propanol (AMP).

[0010] A second aspect of the present invention provides a method for preparing the hybrid matrix membrane described herein, the method comprising:

[0011] The polymer matrix and filler are dispersed in an organic solvent according to a certain ratio to obtain a film-forming solution. The organic solvent in the film-forming solution is then removed and dried to obtain a mixed matrix membrane.

[0012] A third aspect of the present invention provides an application of the hybrid matrix membrane described herein in CO2 membrane separation.

[0013] Through the above technical solution, the filler of the present invention exists as a dispersed phase in the membrane, and the polymer matrix material is composed of a continuous phase polymer; the filler includes MOF material and MA complex amine loaded on MOF material. The MA complex amine coordinates with the metal in MOF material through complex amine coordination, introducing functional groups that can undergo reversible chemical reactions with CO2 into the membrane, thereby enhancing the transfer of CO2 in the membrane, thus overcoming the "trade-off" effect and obtaining a transfer-promoting membrane with both high permeability and high selectivity. Detailed Implementation

[0014] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0015] A first aspect of the present invention provides a hybrid matrix membrane comprising a polymer matrix and fillers dispersed in the polymer matrix;

[0016] The filler includes MOF material and MA composite amine supported on MOF material;

[0017] The MA complex amine is selected from one or more of ethanolamine (MEA), methyl monoethanolamine (MMEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), diisopropylamine (DIPA), hydroxyethyl ethylenediamine (AEEA), and 2-amino-2-methyl-1-propanol (AMP).

[0018] The hybrid matrix membrane uses a polymer matrix material as the continuous phase to form the membrane, with a loaded MA composite amine MOF material as the filler, existing as a dispersed phase within the membrane. MOF materials are novel porous crystalline materials formed through self-assembly between inorganic metal clusters and organic ligands, possessing a large specific surface area and a regular pore structure, effectively enhancing the separation flux of the membrane material. The MA composite amine, through its coordination with the metals in the MOF material, introduces functional groups capable of reversibly reacting with CO2 into the membrane, strengthening CO2 transport within the membrane and overcoming the "trade-off" effect, thereby obtaining a transport-enhancing membrane with both high permeability and high selectivity.

[0019] According to a preferred embodiment of the present invention, the filler content is 3-20 wt% based on the total weight of the mixed matrix membrane.

[0020] According to a preferred embodiment of the present invention, the MOF material comprises:

[0021] Metal center; and

[0022] Organic ligands that hybridize with bimetallic centers through coordination bonds to form a three-dimensional network structure crystal.

[0023] According to a preferred embodiment of the present invention, the metal is selected from one or more of iron, copper, zinc, titanium, cobalt, nickel and chromium.

[0024] According to a preferred embodiment of the present invention, the organic ligand is selected from one or more of benzimidazole, imidazole-2-carboxaldehyde, 2-methylimidazolium, and 2-aminoterephthalic acid.

[0025] In this invention, there is no particular limitation on the preparation method of the MOF material. For example, the MOF material is prepared by solvothermal synthesis, in which the reactants are dispersed in a solvent to form a reaction solution, and then the solution is heated to the required temperature in a hydrothermal reactor to synthesize the material.

[0026] According to a preferred embodiment of the present invention, the MOF material is selected from one or more of NH2-MIL-101(Cr), NH2-MIL-101(Fe), and NH2-MIL-101(Zn).

[0027] The present invention provides an exemplary method for preparing NH2-MIL-101(Cr)MOFs material, comprising: (1) placing 5 mmol and 1500 mg of Cr(NO3)3·9H2O, 5 mmol and 600 mg of NH2-BDC, and 12 mmol and 400 mg of NaOH in 50 mL of deionized water and stirring at room temperature for 15 min.

[0028] (2) Transfer the well dispersed reaction solution to a 200 mL polytetrafluoroethylene reactor, place the reactor in an oven, raise the reaction temperature to 180 °C within 1 hour, react at 180 °C for 12 hours, and then cool down to room temperature for 2 hours.

[0029] (3) The precipitate in the reactor was separated by centrifugation, and then washed several times with N,N'-dimethylformamide and ethanol to remove the unreacted residue in the MOF channels. The product was dried in an oven and then placed in a vacuum oven at 180°C for further activation treatment to obtain the dried MOF material product NH2-MIL-101(Cr).

[0030] According to a preferred embodiment of the present invention, the mass ratio of MA composite amine to MOF material in the filler is 0.5-1:0.8-2, preferably 0.8-1:1.

[0031] According to a preferred embodiment of the present invention, the method for preparing the filler includes:

[0032] MOF materials are contacted with a solution containing MA complex amine, then separated, washed, and dried.

[0033] In this invention, the MOF material can achieve its objective whether it contains bound water or not. According to a preferred embodiment of the invention, the MOF material contains bound water.

[0034] According to a preferred embodiment of the present invention, the conditions for removing bound water from MOF materials include: negative pressure, temperature of 100-180°C, and time of 2-24 hours.

[0035] In this invention, there are no particular limitations on the conditions for contacting the MOF material with the bound water removed with the solution containing MA complex amine. For example, the temperature can be at room temperature (25-30°C) or under heating conditions, preferably at room temperature. According to a preferred embodiment of the present invention, the contact time is 3-20 hours.

[0036] According to a preferred embodiment of the present invention, in the solution containing MA complex amine, the solvent is selected from one or more of anhydrous ethanol, anhydrous methanol, and N,N'-dimethylformamide;

[0037] According to a preferred embodiment of the present invention, the solution containing MA complex amine has a mass ratio of MA complex amine to solvent of 0.2-5:1.

[0038] In this invention, there is no particular limitation on the type of material of the polymer matrix; conventional polymer materials in the art can achieve the purpose of this invention. According to a preferred embodiment of this invention...

[0039] The polymer matrix is ​​selected from one or more of the following: microporous polymer material PIM-1, cellulose polymers, polysulfone polymers, polyamide polymers, amino polymers, and ether oxide polymers, preferably microporous polymer material PIM-1.

[0040] In this invention, there is no particular limitation on the preparation method of the polymer matrix. This invention exemplarily provides a method for preparing the microporous polymer material PIM-1. First, 2,2,5,6-tetrafluoroterephthalonitrile (TFTPN) is purified by vacuum sublimation at 120°C to obtain a white crystalline solid. Then, 2,2,5,6-tetrafluoroterephthalonitrile (TFTPN) is purified by recrystallization in methanol. 35 mmol and 8.2 g of sublimed TFTPN, 35 mmol and 12.5 g of TTSBI recrystallized from methanol, and 80 g and 10.2 g of anhydrous K₂CO₃ are dispersed in 200 mL of anhydrous N,N'-dimethylformamide solution. The reaction is carried out under N₂ purging conditions, with stirring and heating at 60°C for 60 h. After the reaction, the mixture is cooled to room temperature, 300 mL of deionized water is added, and the mixture is filtered. The collected product is then dissolved in CHCl₃ and purified by precipitation in methanol. The product was then dried at 120°C under vacuum for 24 hours.

[0041] A second aspect of the present invention provides a method for preparing the hybrid matrix membrane described herein, the method comprising:

[0042] The polymer matrix and filler are dispersed in the first solvent according to the ratio to obtain the film-forming solution. The organic solvent in the film-forming solution is then removed and dried to obtain the mixed matrix membrane.

[0043] In this invention, there is no particular limitation on the type of the first solvent, as long as it can dissolve the polymer matrix material. According to a preferred embodiment of the present invention, the first solvent is selected from one or more of water, tetrahydrofuran, N,N'-dimethylformamide, methanol, ethanol, dichloromethane, and dimethyl sulfoxide.

[0044] According to a preferred embodiment of the present invention, the total weight of the polymer matrix and filler accounts for 3-10 wt% of the film-forming liquid.

[0045] In this invention, there is no particular limitation on the method of film formation. Conventional film-forming methods in the art can be used in this invention, such as solution casting, solution casting, coating, spinning, and solvent evaporation.

[0046] According to a preferred embodiment of the present invention, the film formation method is casting.

[0047] According to a preferred embodiment of the present invention, the drying conditions in the preparation method of the mixed matrix membrane include: negative pressure, temperature 60-180℃, and time 12-48h.

[0048] A third aspect of the present invention provides an application of the hybrid matrix membrane described herein in CO2 membrane separation, preferably in CO2 / N2 membrane separation.

[0049] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0050] To illustrate the invention more clearly, the following embodiments are provided, but the scope of the invention is not limited to the embodiments.

[0051] Example 1

[0052] (1) The NH2-MIL-101(Cr)MOFs material was dried in a vacuum oven at 150℃ for 12h to remove the water molecules bound in the material;

[0053] (2) Weigh 3.2g of ethanolamine and dissolve it in anhydrous ethanol. Stir magnetically to disperse it evenly. Then add 3.2g of NH2-MIL-101(Cr) in three separate additions and stir for 12h to allow the ethanolamine to fully react with the MOF material. Finally, centrifuge the product and wash it several times with ethanol to remove excess ethanolamine.

[0054] (3) According to the mass ratio, filler:PIM-1=0.05:1, the filler and PIM are mixed with chloroform (the total concentration of PIM-1 and filler in CHCl3 solution is 5.5wt%), and the mixture is uniformly dispersed by ultrasonic stirring to obtain a film-forming solution.

[0055] (4) Then the prepared film-forming solution is degassed and transferred to a clean petri dish. The lid is put on to allow the film solution to evaporate slowly. After the solvent has evaporated, the film is taken out from the petri dish and placed in a vacuum oven at 60°C for 48 hours to obtain a mixed matrix film.

[0056] Example 2

[0057] (1) Weigh 3.2 g of diethanolamine and dissolve it in anhydrous ethanol. Stir magnetically to disperse it evenly. Then, add 3.2 g of NH2-MIL-101(Fe) without dehydrated in three separate additions, stirring for 12 h each time to ensure that the diethanolamine and the NH2-MIL-101(Fe)MOFs material with dehydrated are fully reacted. Finally, centrifuge the product and wash it several times with ethanol to remove excess diethanolamine.

[0058] (2) According to the mass ratio, filler:PIM-1 = 0.1:1, the filler and PIM are mixed with chloroform (the total concentration of PIM-1 and filler in CHCl3 solution is 5.5wt%), and the mixture is uniformly dispersed by ultrasonic stirring to obtain a film-forming solution.

[0059] (3) Then the prepared film-forming solution is degassed and transferred to a clean petri dish. The lid is put on to allow the film solution to evaporate slowly. After the solvent has evaporated, the film is taken out from the petri dish and placed in a vacuum oven at 60°C for 48 hours to obtain a mixed matrix film.

[0060] Example 3

[0061] (1) Weigh 3.2 g of diisopropylamine and dissolve it in anhydrous ethanol. Stir magnetically to disperse it evenly. Then, add 3.2 g of NH2-MIL-101(Zn) without bound water in 5 separate additions and stir for 12 h to ensure that the diisopropylamine and the NH2-MIL-101(Zn) MOFs material without bound water are fully contacted and reacted. Finally, centrifuge the product and wash it with ethanol several times to remove excess diisopropylamine.

[0062] (2) According to the mass ratio, filler:PIM-1 = 0.2:1, the filler and PIM are mixed with chloroform (the total concentration of PIM-1 and filler in CHCl3 solution is 5.5wt%), and the mixture is uniformly dispersed by ultrasonic stirring to obtain a film-forming solution.

[0063] (3) Then the prepared film-forming solution is degassed and transferred to a clean petri dish. The lid is put on to allow the film solution to evaporate slowly. After the solvent has evaporated, the film is taken out from the petri dish and placed in a vacuum oven at 60°C for 48 hours to obtain a mixed matrix film.

[0064] Example 4

[0065] The method is the same as in Example 1, except that in step (3), the mass ratio of the filler to PIM-1 is 0.1:1, and the other conditions are the same as in Example 1.

[0066] Example 5

[0067] The method of Example 1 is the same as in Example 1, except that in step (3), the mass ratio of the filler to PIM-1 is 0.15:1, and the other conditions are the same as in Example 1.

[0068] Example 6

[0069] (1) Weigh 3.2g of ethanolamine and dissolve it in anhydrous ethanol. Stir magnetically to disperse it evenly. Then, add 3.2g of NH2-MIL-101(Cr) without removing bound water in three separate additions and stir for 12h to allow the ethanolamine to fully contact and react with the MOF material. Finally, centrifuge the product and wash it several times with ethanol to remove excess ethanolamine.

[0070] (2) According to the mass ratio, filler:PIM-1=0.05:1, the filler and PIM are mixed with chloroform (the total concentration of PIM-1 and filler in CHCl3 solution is 5.5wt%), and the mixture is uniformly dispersed by ultrasonic stirring to obtain a film-forming solution.

[0071] (3) Then the prepared film-forming solution is degassed and transferred to a clean petri dish. The lid is put on to allow the film solution to evaporate slowly. After the solvent has evaporated, the film is taken out from the petri dish and placed in a vacuum oven at 60°C for 48 hours to obtain a mixed matrix film.

[0072] Example 7

[0073] The method of Example 6 is the same as in Example 6, except that in step (2), the mass ratio of the filler to PIM-1 is 0.10:1, and the other conditions are the same as in Example 6.

[0074] Example 8

[0075] The method of Example 6 is the same as in Example 6, except that in step (2), the mass ratio of the filler to PIM-1 is 0.10:1, and the other conditions are the same as in Example 6.

[0076] Test case

[0077] The performance of the mixed matrix membrane was tested: Membrane samples were pre-humidified and installed in the membrane tank for testing. The feed gases were CO2 (15% vol) and N2 (85% vol). During testing, the feed gases (and purge gases) were humidified in a humidifier before entering the membrane tank. The operating temperature was room temperature (25℃), and the operating pressure was 0.5 MPa(G). After the membrane performance stabilized, the concentrations of the permeate gas (and purge gas) were detected by gas chromatography. The CO2 and N2 permeation rates and the CO2 / N2 separation factor were calculated using general formulas. The test results are shown in Table 1.

[0078] Table 1

[0079]

[0080] Comparative Example 1

[0081] (1) PIM and chloroform were mixed (the total concentration of PIM-1 and filler in CHCl3 solution was 5.5 wt%), and the mixture was ultrasonically stirred to obtain a uniformly dispersed film-forming solution.

[0082] (2) Then the prepared film-forming solution is degassed and transferred to a clean petri dish. The lid is closed to allow the film solution to evaporate slowly. After the solvent has evaporated, the film is removed from the petri dish and placed in a vacuum oven at 60°C for 48 hours to prepare the PIM-1 membrane. According to the above test method, the CO2 permeation rate is 320 GPU and the CO2 / N2 separation factor is 40.

[0083] Comparative Example 2

[0084] (1) According to the mass ratio, NH2-MIL-101(Cr)MOF material: ethanolamine: PIM-1 = 0.025: 0.025: 1, the filler and PIM are mixed with chloroform (the total concentration of PIM-1 and filler in CHCl3 solution is 5.5wt%), and the film-forming solution is obtained by ultrasonic stirring to achieve uniform dispersion.

[0085] (2) Then the prepared film-forming solution is degassed and transferred to a clean petri dish. The lid is put on to allow the film solution to evaporate slowly. After the solvent has evaporated, the film is taken out from the petri dish and placed in a vacuum oven at 60°C for 48 hours to obtain a mixed matrix film.

[0086] According to the above testing method, the CO2 permeation rate is 505 GPUs and the CO2 / N2 separation factor is 60.

[0087] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A hybrid matrix membrane, characterized in that, The hybrid matrix membrane comprises a polymer matrix and fillers dispersed in the polymer matrix; The filler includes MOF material and MA composite amine supported on MOF material; The MA complex amine is selected from one or more of ethanolamine, methyl monoethanolamine, diethanolamine, N-methyldiethanolamine, diisopropylamine, hydroxyethyl ethylenediamine, and 2-amino-2-methyl-1-propanol; The MOF material contains bound water; the MOF material is selected from one or more of NH2-MIL-101(Cr), NH2-MIL-101(Fe) and NH2-MIL-101(Zn).

2. The hybrid matrix membrane according to claim 1, wherein, The filler content is 3-20 wt% based on the total weight of the mixed matrix membrane.

3. The hybrid matrix membrane according to claim 1 or 2, wherein, In the filler, the mass ratio of MA composite amine to MOF material is 0.5-1:0.8-2.

4. The hybrid matrix membrane according to claim 1 or 2, wherein, The method for preparing the filler includes: The MOF material was contacted with a solution containing MA complex amine, and then separated, washed, and dried.

5. The hybrid matrix membrane according to claim 4, wherein, In the solution containing MA complex amine, the solvent is selected from one or more of anhydrous ethanol, anhydrous methanol, and N,N'-dimethylformamide; In solutions containing MA complex amine, the mass ratio of MA complex amine to solvent is 0.2-5:

1.

6. The hybrid matrix membrane according to claim 1 or 2, wherein, The polymer matrix is ​​selected from one or more of the following: microporous polymer material PIM-1, cellulose polymers, polysulfone polymers, polyamide polymers, amino polymers, and ether oxide polymers.

7. The hybrid matrix membrane according to claim 1 or 2, wherein, The polymer matrix is ​​a microporous polymer material, PIM-1.

8. The method for preparing the hybrid matrix membrane according to any one of claims 1-7, characterized in that, The method includes: The polymer matrix and filler are dispersed in an organic solvent according to a certain ratio to obtain a film-forming solution. The organic solvent in the film-forming solution is then removed and dried to obtain a mixed matrix membrane.

9. The preparation method according to claim 8, The organic solvent is selected from one or more of water, tetrahydrofuran, N,N'-dimethylformamide, methanol, ethanol, dichloromethane, and dimethyl sulfoxide; and / or The total weight of the polymer matrix and fillers accounts for 1-15 wt% of the film-forming solution; and / or Drying conditions include: Negative pressure, temperature 60-150℃, time 2-24h.

10. The application of the hybrid matrix membrane according to any one of claims 1-7 in CO2 membrane separation.

11. The application according to claim 10, wherein, Application of mixed matrix membranes in CO2 membrane separation.

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