Use of a high performance metal organic framework membrane in membrane separation
The preparation of dense metal-organic framework membranes by interfacial polymerization solves the problem of high energy consumption in traditional separation technologies, achieving efficient gas and liquid phase separation. In particular, it exhibits excellent performance in hydrogen/carbon dioxide separation, making it suitable for large-scale industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-12-04
- Publication Date
- 2026-06-05
AI Technical Summary
Traditional separation technologies are energy-intensive and costly in gas sieving and liquid phase separation. The preparation and application of existing metal-organic framework materials face challenges, making it difficult to prepare membrane materials with high separation performance on a large scale.
Metal-organic framework membranes were prepared by interfacial polymerization. Dense metal-organic framework membranes were prepared by direct growth and seed-induced growth. Molecular sieving was carried out by utilizing their pore size sieving and adsorption properties, including hydrogen/carbon dioxide purification, dye purification and alcohol-water separation.
It achieves high-efficiency gas and liquid phase separation performance, especially in hydrogen/carbon dioxide separation systems, with a separation coefficient of about 350. At the same time, it is simple to operate, low in cost, and suitable for large-scale industrial production.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal-organic framework membrane preparation and application, specifically relating to a method for preparing metal-organic framework membranes using interfacial polymerization and applying them to gas sieving and liquid phase separation. Background Technology
[0002] In key processes of the chemical industry, gas sieving and liquid-phase separation consume significant amounts of energy. Traditional separation technologies require expensive equipment investment and substantial energy consumption, thus significantly increasing separation costs. Guided by the goals of "carbon peaking and carbon neutrality," researchers are constantly seeking more efficient new separation technologies. Membrane separation technology, due to its high efficiency and energy-saving characteristics, is considered a third-generation separation technology. In recent years, metal-organic frameworks (MOFs) have been recognized as promising molecular sieving membrane materials due to their diverse structures and uniform, controllable pore sizes. Currently, the development of MOFs faces constraints from multiple factors, including material selection, separation applications, and preparation costs. Therefore, developing large-scale production of membrane materials with excellent separation performance at a suitable cost is of great significance to the development of the chemical industry. Summary of the Invention
[0003] This invention aims to provide an application of high-performance metal-organic framework membranes in membrane separation. By utilizing the pore size sieving and adsorption properties of metal-organic framework membranes, substances with similar molecular sizes and chemical properties can be efficiently sieved. Applications include hydrogen / carbon dioxide purification, dye purification, and alcohol-water separation.
[0004] The objective of this invention is achieved through the following technical solutions.
[0005] An application of a high-performance metal-organic framework membrane in membrane separation, wherein the metal-organic framework membrane has a dense and defect-free surface morphology and plays a role in gas sieving and liquid phase separation.
[0006] Based on the above technical solutions, preferably, the metal center of the metal-organic framework membrane includes Co or Ca.
[0007] Based on the above technical solutions, preferably, the organic ligands of the metal-organic framework membrane include one or more of terephthalic acid, 2-methylimidazole, isophthalic acid, gallic acid and squaric acid, and more preferably one or more of squaric acid and gallic acid.
[0008] Based on the above technical solutions, preferably, the metal-organic framework membrane is prepared by the following method:
[0009] (1) Dissolve the metal salt and regulator in a solvent to prepare a metal salt solution; the molar ratio of the metal salt, regulator and solvent in the metal salt solution is 0.01~1:0~10:1~10000, preferably 1:0.1~0.3:10~100;
[0010] The organic ligand and modifier are dissolved in a solvent to prepare an organic ligand solution; the molar ratio of the organic ligand, modifier and solvent in the organic ligand solution is 0.01-1:0-10:1-10000, preferably 1:1-3:10-100.
[0011] (2) Under stirring conditions, the metal salt solution from step (1) is mixed with the organic ligand solution and reacted to prepare metal-organic framework material seed crystals.
[0012] (3) The metal-organic framework material seed crystals prepared in step (2) are loaded onto the substrate by a certain method to obtain the substrate loaded with the seed crystals.
[0013] (4) Place the blank substrate or the substrate loaded with seed crystals at the interface of the metal salt solution and the organic ligand solution in step (1), react under certain conditions, remove it, and rinse it with an appropriate solvent to obtain a dense metal-organic framework film.
[0014] Based on the above technical solutions, preferably, in step (1), the thickness of the metal-organic framework film is 10nm-100μm.
[0015] Based on the above technical solutions, preferably, in step (1), the metal salt is one or more of the following: nitrate, chloride, and acetate of metals (e.g., Ca, Co).
[0016] Based on the above technical solutions, preferably, in step (1), the organic ligand includes one or more of terephthalic acid, 2-methylimidazole, isophthalic acid, gallic acid and squaric acid, preferably one or more of squaric acid and gallic acid.
[0017] Based on the above technical solutions, preferably, in step (1), the regulator includes one or more of ammonia, ethylenediamine, potassium hydroxide, sodium hydroxide, 1,8-octanediamine, acetic acid, sodium hydroxide, and potassium hydroxide.
[0018] Based on the above technical solutions, preferably, in step (1), the acetic acid is an acidic regulator, and the regulator other than acetic acid is an alkaline regulator; when the acidic regulator and the alkaline regulator are used at the same time, the molar ratio of the acidic regulator and the alkaline regulator is 0.01 to 100:1, preferably 0.1 to 5:1.
[0019] Based on the above technical solutions, preferably, in step (1), the solvent is one or more of alcohols, ethers, ketones, amides, lipids, and nitriles, preferably a mixture of water, ethanol in step (3), and N,N-dimethylformamide.
[0020] Based on the above technical solutions, preferably, in step (2), under stirring conditions, the metal salt solution from step (1) is slowly added dropwise to the organic ligand solution, and the reaction is carried out at 25-100℃ for 12-72 hours to obtain metal-organic framework material seed crystals.
[0021] Based on the above technical solutions, preferably, the volume ratio of the metal salt solution to the organic ligand solution is 0.1-100:0.1-100, and more preferably 1-10:1-10.
[0022] Based on the above technical solutions, preferably, in step (2), the slow dripping is done drop by drop.
[0023] Based on the above technical solutions, preferably, in step (2), the metal-organic framework material seed crystals include ZIF series, MIL series, CAU series, UTSA-280, M-gallate and other metal-organic framework materials or their modified derivatives.
[0024] Based on the above technical solutions, preferably, in step (3), the substrate is a porous carrier, which is one or more of alumina, anodic aluminum oxide, polyamide, polyimide, polytetrafluoroethylene, polysulfone, polyethersulfone, polyacrylonitrile, and stainless steel. The porous carrier has a sheet-like structure, a mesh structure, a fiber structure, or a tubular structure. The pore size of the porous carrier is 50-10000 nm, preferably 70-220 nm.
[0025] Based on the above technical solutions, preferably, in step (3), the method of loading seed crystals is one or more of the following: dripping, dip-coating, soaking, spin coating, spraying, scraping, and filtration.
[0026] Based on the above technical solution, preferably, in step (4), the volume ratio of the metal salt solution to the organic ligand solution is 10-1000:10-1000, more preferably 10-50:10-50. For example, the metal salt solution and the organic ligand solution are 10-1000 mL each, more preferably 10-50 mL.
[0027] Based on the above technical solutions, preferably, in step (4), the reaction temperature is 0-200℃, preferably 30-120℃; the time is 12-720h, preferably 12-80h.
[0028] Based on the above technical solutions, preferably, in step (4), the rinsing solvent is one or a combination of several of the following solvents: water, methanol, ethanol, and acetone.
[0029] Based on the above technical solutions, preferably, the applications include at least one of hydrogen / carbon dioxide purification, ethylene / ethane separation, dye purification (e.g., Evans blue, methyl orange), and alcohol-water separation (e.g., methanol, ethanol). The metal-organic framework membrane of this invention can achieve a separation coefficient of over 350 in a hydrogen / carbon dioxide separation system, a selectivity of 2-4 for ethylene / ethane separation, a dye rejection rate of up to 98%, and a selectivity of 40-100 in an alcohol-water separation system.
[0030] Based on the above technical solutions, preferably, a metal-organic framework membrane is encapsulated in a Wicke-Kallenbach membrane module, a mixed gas is introduced into one side, and an inert gas (such as nitrogen) is used to purge the other side to achieve efficient separation of the mixed gas.
[0031] Based on the above technical solutions, preferably, a metal-organic framework membrane is encapsulated in a filtration device, and the separation performance is tested using an aqueous solution of dye (e.g., 10 mol / L) as the raw material.
[0032] Based on the above technical solutions, preferably, a metal-organic framework membrane is encapsulated in a pervaporation device to test the separation performance of the mixed solution.
[0033] Beneficial effects: This invention utilizes interfacial polymerization to prepare metal-organic framework membranes with dense surface morphology through direct growth and seed-induced growth. These membranes exhibit excellent performance in gas sieving and liquid-phase separation systems, particularly in hydrogen / carbon dioxide separation systems, where the isomeric separation coefficient reaches approximately 350. Furthermore, the simple synthesis process and low cost facilitate large-scale industrial production. Attached Figure Description
[0034] This invention appendix Figure 3 The images are:
[0035] Figure 1 Scanning electron microscope image of the prepared UTSA-280 seed crystals.
[0036] Figure 2 This is a scanning electron microscope image of the surface of a UTSA-280 film prepared on a substrate using interfacial polymerization.
[0037] Figure 3 This is a scanning electron microscope image of the surface of a Co-gallate film prepared on a substrate using interfacial polymerization. Detailed Implementation
[0038] The following embodiments will further illustrate the present invention, but are not intended to limit the invention.
[0039] Example 1: Preparation of UTSA-280 seed crystals
[0040] 3.84 g of sodium hydroxide, 2.97 g of calcium nitrate tetrahydrate, and 4.82 g of acetic acid were dissolved in 20 mL of deionized water to obtain a metal salt solution. 0.46 g of squaric acid and 0.38 g of sodium hydroxide were dissolved in 32 mL of deionized water to obtain a colorless and transparent organic ligand solution. After sonicating the above solutions for 30 min, the metal salt solution was added dropwise to the organic ligand solution under stirring at room temperature for 24 h to obtain UTSA-280 seed crystals. 10 mg of the seed crystals were dispersed in 100 mL of methanol to obtain a dispersion. 10 mL of the dispersion was filtered and placed on a vinylidene fluoride substrate (0.22 μm pore size) with a diameter of 18 mm. After standing and drying, a substrate loaded with UTSA-280 seed crystals was obtained.
[0041] Scanning electron microscopy showed that the seed crystals had a nanosheet morphology (e.g. Figure 1 ).
[0042] Example 2: Preparation of UTSA-280 film on polyvinylidene fluoride substrate
[0043] A method for preparing metal-organic framework membranes using interfacial polymerization secondary growth involves placing a substrate at the interface between a metal salt and an organic ligand, and utilizing confined reaction and self-inhibition effect to obtain a dense metal-organic framework membrane.
[0044] (1) Prepare the solution required for UTSA-280 membrane growth: Dissolve 1.45g sodium hydroxide, 1.67g calcium nitrate tetrahydrate and 2.26g acetic acid in 40mL of deionized water to obtain a metal salt solution; Dissolve 0.13g squaric acid and 0.19g sodium hydroxide in 16mL of deionized water to obtain a colorless and transparent organic ligand solution.
[0045] (2) The substrate loaded with UTSA-280 seeds prepared in Example 1 was placed on the surface of the organic ligand solution in step (1), sealed, and then the metal salt solution prepared in step (1) was added so that the substrate was located at the interface between the metal salt solution and the organic ligand solution. The reaction was carried out at room temperature for 72 hours to obtain a dense UTSA-280 film.
[0046] The obtained UTSA-280 film was characterized by scanning electron microscopy (SEM). The SEM characterization results are as follows: Figure 2 As shown in the figure, the UTSA-280 membrane surface is dense and without defects.
[0047] Example 3: Preparation of Co-gallate Film on Porous Alumina Substrate
[0048] A method for preparing metal-organic framework membranes by in-situ growth using interfacial polymerization involves placing a substrate at the interface between a metal salt and an organic ligand, and utilizing confined reaction and self-inhibition effect to obtain a dense metal-organic framework membrane.
[0049] (1) A porous alumina substrate with a diameter of 18 mm (pore size 70 nm) was rinsed with water and acetone for 2 minutes to remove surface stains.
[0050] (2) Prepare the solution required for the growth of Co-gallate membrane: Dissolve 0.25g of cobalt acetate in 20mL of deionized water to obtain a metal salt solution; dissolve 0.13g of gallic acid and 0.04g of potassium hydroxide in 20mL of deionized water to obtain a clear and transparent organic ligand solution.
[0051] (3) Place the cleaned substrate on the surface of the metal salt solution in step (2), seal it, and add the organic ligand solution prepared in step (2) so that the substrate is located at the interface between the metal salt solution and the organic ligand solution. React at 120°C for 24 hours to obtain a dense Co-gallate film.
[0052] The obtained Co-gallate film was characterized by scanning electron microscopy (SEM). The SEM characterization results are as follows: Figure 3 As shown in the figure, the surface of the Co-gallate film is dense and without defects.
[0053] Example 4: Gas separation performance test of hydrogen / carbon dioxide separation membrane
[0054] The UTSA-280 and Co-gallate membranes prepared in Examples 2 and 3 were encapsulated in a Wicke-Kallenbach membrane module. Equimolar hydrogen / carbon dioxide mixed gas separation tests were conducted under ambient temperature and zero transmembrane pressure differential conditions, with argon as the purge gas. (1 GPU = 1 × 10⁻⁶ under standard conditions) -6 cm 3 / cm 2 (·s·cmHg). Table 1, 2, and 3 below show the gas separation performance of the three UTSA-280 and Co-gallate membranes prepared in Examples 2 and 3.
[0055] membrane <![CDATA[H2 / CO2 separation factor]]> <![CDATA[H2 Permeability (GPU)]]> <![CDATA[CO2 Permeability (GPU)]]> UTSA-280-1 348 950 2.7 UTSA-280-2 375 1096 2.9 UTSA-280-3 352 1017 2.8 Co-gallate-1 542 621 1.1 Co-gallate-2 554 704 1.2 Co-gallate-3 586 648 1.1
[0056] Example 5: Separation performance of the dye separation test membrane
[0057] The UTSA-280 and Co-gallate membranes prepared in Examples 2 and 3 were encapsulated in a filtration device. The membranes were first subjected to a water pressure process at 5 bar for one hour, and pure water permeation reached equilibrium after approximately 30 minutes. Then, a water purification test was conducted at 1 bar for 1 hour. Separation performance was tested using Evans blue aqueous solution (10 mol / L) as the feed. The concentrations of the feed solution and the permeate solution were measured using UV / Vis spectroscopy. To eliminate concentration polarization on the feed side, the feed volume was kept constant at 500 mL. Table 1, 2, and 3 below show the three UTSA-280 and Co-gallate membranes prepared in Examples 2 and 3.
[0058] membrane Evans blue dye removal rate % <![CDATA[Water flux (L / m -2 h -1 )]]> UTSA-280-1 98.3 45 UTSA-280-2 98.6 38 UTSA-280-3 98.1 39 Co-gallate-1 94.4 84 Co-gallate-2 95.3 92 Co-gallate-3 95.1 88
[0059] Example 6: Ethanol / Water Separation Test of UTSA-280 Membrane; Liquid Separation Performance Test of the Membrane
[0060] The UTSA-280 and Co-gallate membranes prepared in Examples 2 and 3 were evaluated for ethanol (90 wt% ethanol / water) dehydration using pervaporation technology. The vapor permeating through the membrane was collected after condensation in liquid nitrogen. The real-time component concentrations of the feed solution and the condensed permeate solution were studied using gas chromatography. Tables 1, 2, and 3 below show the three UTSA-280 and Co-gallate membranes prepared in Examples 2 and 3. The data in the tables demonstrate the liquid-phase separation performance of these membrane materials.
[0061] membrane Ethanol / Water Separation Coefficient <![CDATA[Total flux (kg / m -2 h -1 )]]> UTSA-280-1 75 1.4 UTSA-280-2 86 1.7 UTSA-280-3 94 1.2 Co-gallate-1 36 2.5 Co-gallate-2 38 2.8 Co-gallate-3 44 2.4
[0062] Example 7: Ethylene / Ethane Separation Test of Co-gallate Membrane; Gas Separation Performance Test of the Membrane
[0063] The UTSA-280 and Co-gallate membranes prepared in Examples 2 and 3 were encapsulated in a Wicke-Kallenbach membrane module. Equimolar ethylene / ethane mixed gas separation tests were conducted under ambient temperature and zero transmembrane pressure differential conditions, with argon as the purge gas. (1 GPU = 1 × 10⁻⁶ under standard conditions) -6 cm 3 / cm 2 (·s·cmHg). Tables 1, 2, and 3 below show the three UTSA-280 and Co-gallate membranes prepared in Examples 2 and 3. The data in the tables show that this membrane material has certain potential in the separation of ethylene and ethane systems.
[0064] membrane <![CDATA[Separation coefficient of C2H4 / C2H6]]> <![CDATA[C2H4 Permeability (GPU)]]> <![CDATA[C2H6 Permeation Rate (GPU)]]> UTSA-280-1 2.4 24 10 UTSA-280-2 2.7 32 12 UTSA-280-3 2.9 28 10 Co-gallate-1 3.5 4.5 1.2 Co-gallate-2 3.8 6.4 1.6 Co-gallate-3 4.1 6.6 1.6
Claims
1. An application of a high-performance metal-organic framework membrane in membrane separation, characterized in that, The metal-organic framework membrane has a dense and defect-free surface morphology and is used in gas sieving and liquid phase separation.
2. The application according to claim 1, characterized in that, The metal-organic framework membrane has a metal center including Co or Ca, and the organic ligands of the metal-organic framework membrane include one or more of terephthalic acid, 2-methylimidazole, isophthalic acid, gallic acid and squaric acid.
3. The application according to claim 1, characterized in that, The method for preparing the metal-organic framework membrane includes the following steps: (1) Dissolve the metal salt and regulator in a solvent to prepare a metal salt solution; the molar ratio of the metal salt, regulator and solvent in the metal salt solution is 0.01~1:0~10:1~10000; An organic ligand and a modifier are dissolved in a solvent to prepare an organic ligand solution; the molar ratio of the organic ligand, modifier and solvent in the organic ligand solution is 0.01-1:0-10:1-10000. (2) Under stirring conditions, the metal salt solution from step (1) is mixed with the organic ligand solution and reacted to prepare metal-organic framework material seed crystals; (3) Load the metal-organic framework material seed crystals prepared in step (2) onto the substrate to obtain the substrate loaded with seed crystals; (4) Place the blank substrate or the substrate loaded with seed crystals at the interface of the metal salt solution and the organic ligand solution in step (1), react under certain conditions, remove it, and rinse it with an appropriate solvent to obtain a dense metal-organic framework film.
4. The application according to claim 3, characterized in that, In step (1), the regulator includes one or more of ammonia, ethylenediamine, potassium hydroxide, sodium hydroxide, 1,8-octanediamine, acetic acid, sodium hydroxide, and potassium hydroxide; the solvent is one or more of alcohols, ethers, ketones, amides, lipids, and nitriles, preferably a mixture of one or more of water, ethanol, and N,N-dimethylformamide. In step (2), under stirring conditions, the metal salt solution from step (1) is slowly added dropwise to the organic ligand solution, and the reaction is carried out at room temperature for 12-72 hours to obtain metal-organic framework material seed crystals; the volume ratio of the metal salt solution to the organic ligand solution is 0.1-100:0.1-100.
5. The application according to claim 4, characterized in that, The slow addition is a drop-by-drop addition; the metal-organic framework material seed crystals include ZIF series, MIL series, CAU series, UTSA-280, M-gallate metal-organic framework materials or their modified derivatives.
6. The application according to claim 3, characterized in that, In step (3), the substrate is a porous carrier, which is one or more of alumina, anodic alumina, polyamide, polyimide, polytetrafluoroethylene, polysulfone, polyethersulfone, polyacrylonitrile, and stainless steel. The porous carrier has a sheet-like structure, a mesh structure, a fiber structure, or a tubular structure. The pore size of the porous carrier is 50-10000 nm. In step (4), the volume ratio of the metal salt solution to the organic ligand solution is 10-1000:10-1000; the reaction temperature is 0-200℃ and the time is 12-720h; the rinsing solvent is one or a combination of several of the following solvents: water, methanol, ethanol, and acetone.
7. The application according to claim 1, characterized in that, The applications include at least one of hydrogen / carbon dioxide purification, ethylene / ethane separation, dye purification, and alcohol-water separation.
8. The application according to claim 1, characterized in that, The metal-organic framework membrane is encapsulated in a Wicke-Kallenbach membrane module. A mixed gas is introduced into one side, and an inert gas is used to purge the other side to separate the mixed gas.
9. The application according to claim 1, characterized in that, Metal-organic framework membranes were encapsulated in a filtration device, and their separation performance was tested using an aqueous solution of dye as the feed liquid.
10. The application according to claim 1, characterized in that, Metal-organic framework membranes were encapsulated in a pervaporation device to test the separation performance of mixed solutions.