A high-pressure resistant membrane based on metal-organic polyhedra, its preparation method and application
By combining metal-organic polyhedra with rigid polymers and then subjecting them to heat treatment, a high-pressure resistant hybrid matrix membrane was prepared, solving the problems of interface stability and structural integrity under high pressure and achieving high-efficiency gas separation performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHENGDU ORGANIC CHEM CO LTD CHINESE ACAD OF SCI
- Filing Date
- 2026-03-03
- Publication Date
- 2026-05-26
AI Technical Summary
Traditional polymer membrane materials are prone to interface defects, plasticization, or structural collapse under high-pressure operating conditions, which leads to a significant decrease in separation performance and limits their application in high-pressure gas separation scenarios.
A high-pressure resistant hybrid matrix membrane was prepared by using metal-organic polyhedra as fillers, combining them with rigid polymers, and enhancing interfacial bonding and membrane densification through heat treatment.
It improves the mechanical stability and gas separation performance of the membrane, maintains high permeability and selectivity, and can operate stably under high pressure, making it suitable for high-pressure industrial processes.
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Figure CN122076244A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer materials technology, specifically relating to a high-pressure resistant membrane based on metal-organic polyhedra, its preparation method, and its application. Background Technology
[0002] Traditional gas separation methods, such as cryogenic distillation and adsorption separation, suffer from drawbacks such as high energy consumption and complex equipment. Membrane separation technology, as a novel separation method, has attracted widespread attention in recent years due to its advantages of low energy consumption, simple operation, and environmental friendliness. However, traditional polymer membrane materials often face a "trade-off" effect, meaning that permeability and selectivity are difficult to improve simultaneously, limiting their performance in practical applications. Mixed matrix membranes (MMMs), which disperse inorganic fillers in a polymer matrix, combine the excellent gas separation performance of inorganic materials with the good processability of polymers, and have become a research hotspot in the field of gas separation. However, many mixed matrix membranes are prone to interfacial defects, plasticization, or structural collapse under high-pressure operating conditions, leading to a significant decrease in separation performance and severely restricting their application in high-pressure gas separation scenarios (such as natural gas purification and syngas treatment). Therefore, developing high-pressure resistant mixed matrix membranes that can operate stably and maintain high performance under high-pressure environments has become a key problem urgently needing to be solved in the field of gas separation membranes. Summary of the Invention
[0003] To address the challenge of developing high-pressure resistant hybrid matrix membranes capable of stable operation and high performance under high-pressure environments, this invention provides a high-pressure resistant membrane based on metal-organic polyhedra, its preparation method, and its applications. Compared to the widely studied metal-organic frameworks, metal-organic polyhedra are discrete nanocage-like structures formed by the self-assembly of metal ions and organic ligands. They possess advantages such as uniform size, tunable structure, and easy surface functionalization. Furthermore, their discrete cage-like structure often better alleviates interfacial stress caused by the difference in expansion coefficients between polymers and fillers under high pressure, thereby reducing defect formation. Heat treatment, as an effective post-treatment method, can not only eliminate defects generated during membrane preparation and improve membrane density but also further enhance the interfacial interaction between the polymer and filler, thereby strengthening the mechanical stability of the membrane under high pressure. In conclusion, developing a high-pressure resistant hybrid matrix membrane based on metal-organic polyhedra to solve the problems of interfacial stability and structural integrity under high-pressure operation is of great significance for expanding the application of gas separation membrane technology in high-pressure industrial processes. This invention uses metal-organic polyhedra with high structural stability and easy interface modification as fillers, combined with polymers with excellent mechanical strength and heat resistance, and further enhances the interfacial bonding and membrane densification through heat treatment process, thereby preparing a hybrid matrix membrane that can withstand high pressure operating conditions and has high gas permeability and selectivity.
[0004] The technical solution adopted in this invention is as follows:
[0005] A high-pressure resistant membrane based on metal-organic polyhedra is obtained by using a rigid polymer as the matrix material and doping it with metal-organic polyhedra, wherein the amount of metal-organic polyhedra added accounts for 10 wt% to 50 wt% of the total material.
[0006] Preferably, the rigid polymer is one or more of polybenzimidazole, polyimide, and polysulfone.
[0007] Preferably, the metal nodes of the metal-organic polyhedron are one of zirconium-based, iron-based, and rare earth-based, and the metal-organic polyhedron is one of carboxylic acid ligands, nitrogen-containing ligands, phosphate groups, and sulfonate groups.
[0008] A method for preparing a high-voltage resistant membrane based on a metal-organic polyhedron includes the following steps:
[0009] S1: Preparation of rigid polymer solution;
[0010] S2: Mix the metal-organic polyhedron with a rigid polymer solution to obtain a metal-organic polyhedron-polymer casting solution;
[0011] S3: Prepare a membrane using a metal-organic polyhedron-polymer casting solution;
[0012] S4: Heat-treat the membrane to obtain a high-pressure resistant membrane based on metal-organic polyhedra.
[0013] Preferably, in step S4, the membrane is placed in a high-temperature tube furnace and heat-treated under a nitrogen or argon atmosphere.
[0014] Preferably, the heat treatment temperature is 300-600 ℃.
[0015] Preferably, the rigid polymer in the rigid polymer solution in S1 has a mass fraction of 3-5 wt%, and the solvent for preparing the rigid polymer solution is an anhydrous aprotic polar solvent.
[0016] Preferably, the solvent is one of dimethyl sulfoxide and N,N-dimethylacetamide.
[0017] Preferably, in step S3, film formation is achieved by removing the solvent, and the solvent removal temperature is 80~200 ℃.
[0018] Application of a high-pressure resistant membrane based on a metal-organic polyhedron, or the preparation method of the high-pressure resistant membrane based on a metal-organic polyhedron, in gas separation.
[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0020] This invention utilizes the excellent dispersion properties of metal-organic polyhedra to avoid filler agglomeration and the formation of non-selective defects. Heat treatment at 300-600℃ further enhances interfacial interactions, improving membrane density and stability. Rigid polymers prevent dense chain stacking through conformational confinement, while metal-organic polyhedra provide additional transport channels and inhibit excessive chain collapse during heat treatment. Together, they form a composite material with a stable hierarchical pore structure, effectively improving membrane separation performance. The membrane exhibits He permeability of 50.6~164.6 Barrer, H2 permeability of 50.6~360.9 Barrer, CO2 permeability of 6~89.8 Barrer, and CH4 permeability of 0.06~0.35 Barrer. The He / CH4 selectivity is 304.9~774.7, the H2 / CH4 selectivity is 892.0~2037.9, and the CO2 / CH4 selectivity is 79.2~472.6. When the feed pressure was increased from 4 bar to 20 bar, the He / CH4 selectivity of the hybrid matrix membrane of the metal-organic framework decreased by 67% compared to that of the conventional metal-organic framework, while the He / CH4 selectivity of the hybrid matrix membrane of the metal-organic polyhedron decreased by only 19%.
[0021] Instruction manual illustrations
[0022] Figure 1 SEM images of the products from Examples 1-4;
[0023] Figure 2 This is a graph showing the trend of selectivity and permeability changes under test pressures of 4-20 bar in Example 4.
[0024] Figure 3 This is a graph showing the trend of selectivity and permeability under test pressures of 4-20 bar for Comparative Example 1. Detailed Implementation
[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0026] Example 1
[0027] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0028] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0029] S2: Weigh 0.05 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0030] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0031] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 600℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 11 wt%.
[0032] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0033] Example 2
[0034] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0035] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0036] S2: Weigh 0.1 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0037] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0038] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 600℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 20 wt%.
[0039] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0040] Example 3
[0041] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0042] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0043] S2: Weigh 0.2 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0044] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0045] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The high-pressure resistant membrane based on metal-organic polyhedra with a loading of 33 wt% was obtained by heating to 600℃, holding at that temperature for 2 h, and then cooling to room temperature.
[0046] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0047] Example 4
[0048] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0049] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0050] S2: Weigh 0.4 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0051] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0052] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 600℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt%.
[0053] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2. Under the condition of 50 / 50 (V:V) mixed gas, the feed pressure was increased from 4 bar to 20 bar for pressure resistance test.
[0054] Example 5
[0055] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0056] S1: Dissolve polysulfone (0.4 g) in 14 ml DMSO. After the polyethersulfone is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0057] S2: Weigh 0.4 g of iron-based metal-organic polyhedron (Fe-MOP, obtained by reacting metal source Fe2(SO4)3 and organic ligand terephthalic acid in DMF at 100 °C for 48 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0058] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0059] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 600℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt%.
[0060] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0061] Example 6
[0062] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0063] S1: Dissolve 0.4 g of polyimide in 14 ml of DMSO. After the polyimide is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0064] S2: Weigh 0.4 g of rhodium-based metal-organic polyhedron (Rh-MOP, obtained by reacting metal source Rh2(OAc)4 and organic ligand isophthalic acid in DMAc at 100 °C for 48 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0065] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0066] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 600℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt%.
[0067] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0068] Example 7
[0069] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0070] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0071] S2: Weigh 0.4 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0072] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0073] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 300℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt%.
[0074] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0075] Example 8
[0076] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0077] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0078] S2: Weigh 0.4 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0079] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0080] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 450℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt%.
[0081] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0082] Comparative Example 1
[0083] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0084] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0085] S2: Weigh 0.4 g of zirconium-based metal-organic framework (Uio-66-NH2, obtained by reacting metal source ZrCl4 with organic ligand 2-aminoterephthalic acid in DMF at 130 °C for 48 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0086] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0087] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 600℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt%.
[0088] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2. Under the condition of 50 / 50 (V:V) mixed gas, the feed pressure was increased from 4 bar to 20 bar for pressure resistance test.
[0089] Comparative Example 2
[0090] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0091] S1: Dissolve polyethylene glycol (0.4g) in 14 ml DMSO. After the polyethylene glycol is completely dissolved, filter the solution using a filter membrane to obtain a polymer solution.
[0092] S2: Weigh 0.4 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0093] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0094] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 600℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt%.
[0095] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0096] Comparative Example 3
[0097] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0098] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0099] S2: Weigh 0.4 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0100] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0101] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 600℃, held for 2 h, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 60 wt%.
[0102] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0103] Comparative Example 4
[0104] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0105] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0106] S2: Weigh 0.4 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0107] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0108] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt% was obtained by heating to 100℃, holding at that temperature for 2 h, and then cooling to room temperature.
[0109] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0110] Comparative Example 5
[0111] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0112] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0113] S2: Weigh 0.4 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0114] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0115] S4: Place the above membrane in a high-temperature tube furnace and, under a nitrogen atmosphere, reduce the temperature from room temperature to 20°C / min. -1 The temperature was raised to 900℃, held for 2 hours, and then cooled to room temperature to obtain a high-pressure resistant membrane based on metal-organic polyhedra with a loading of 50 wt%.
[0116] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0117] Comparative Example 6
[0118] A high-pressure resistant membrane based on metal-organic polyhedra includes the following steps:
[0119] S1: Dissolve 0.4 g of polybenzimidazole in 14 ml of DMSO. After the polybenzimidazole is completely dissolved, filter the solution using a filter membrane to obtain a rigid polymer solution.
[0120] S2: Weigh 0.4 g of zirconium-based metal-organic polyhedron (ZrT-NH2, obtained by reacting metal source Cp2ZrCl2 and organic ligand 2-aminoterephthalic acid in DMAc at 80 °C for 10 h and collecting the obtained crystals) and add it to the polymer solution. Stir for 12 h to obtain zirconium-based metal-organic polyhedron-polymer casting solution.
[0121] S3: Spread the casting solution evenly on the glass template, place it in an oven and dry it under vacuum at 80 ℃ for 12 h, then continue to raise the temperature to 160 ℃ and dry for 6 h to completely remove the solvent and prepare the film;
[0122] The obtained high-pressure resistant membrane was subjected to gas separation test at 4 bar, and the results are shown in Table 2.
[0123] The parameter changes in Examples 1-8 and Comparative Examples 1-6 are shown in Table 1:
[0124] Table 1
[0125]
[0126] Gas permeability tests were conducted on the membranes prepared in Examples 1-8 and Comparative Examples 1-6. The tests employed the constant-volume pressure swing method, using a pressure sensor to detect changes in downstream pressure. Specifically, the gas permeability P (1 Barrer = 10⁻⁶) was measured. −10 cm 3 (STP) cm cm −2 s −1 cmHg −1 Calculate using the following formula:
[0127]
[0128] The selectivity of gases A and B is calculated using the following formula:
[0129]
[0130] The test results are shown in Table 2:
[0131] Table 2
[0132]
[0133] According to the test results in Table 2, the membranes described in Examples 1-8 have the following permeability values: He permeability is 50.6~164.6 Barrer, H2 permeability is 50.6~360.9 Barrer, CO2 permeability is 6~89.8 Barrer, CH4 permeability is 0.06~0.35 Barrer, He / CH4 selectivity is 304.9~774.7, H2 / CH4 selectivity is 892.0~2037.9, and CO2 / CH4 selectivity is 79.2~472.6.
[0134] As can be seen from Examples 1-4, with the increase of metal-organic polyhedron content, the permeability of the membrane for He and H2 gases increases, and the selectivity for He / CH4 and H2 / CH4 also increases accordingly, indicating that the amount of metal-organic polyhedron added is very important for the membrane performance. However, Comparative Example 5 shows that when the amount of metal-organic polyhedron added reaches 60 wt%, its excessive doping disrupts the continuous film-forming ability of the polymer matrix, leading to defects in the membrane structure, thereby causing a simultaneous decrease in permeability and selectivity.
[0135] Examples 5 and 6 exhibited excellent permeability and selectivity, demonstrating that iron-based and rhodium-based metal-organic polyhedra also have good interfacial compatibility with polymer matrices.
[0136] As can be seen from Example 4 and Comparative Example 1, compared with metal-organic frameworks, metal-organic polyhedra have better interfacial compatibility with polymers and higher selectivity.
[0137] Comparative Example 2 demonstrates that compared to flexible polymer structures, which are more prone to chain segment rearrangement leading to decreased gas selectivity, rigid polymers have restricted chain segment movement and can form microporous structures with stronger size sieving capabilities and greater stability, thus making them more suitable for efficient gas separation.
[0138] Comparing Examples 4-6 further verifies the criticality of post-processing temperature. When the temperature is too low, the membrane permeability is low, while when the temperature is too high, the membrane structure is damaged, leading to a decrease in selectivity.
[0139] SEM images of Examples 1-4 are shown below. Figure 1 As can be observed from the figure, the metal-organic polyhedra are uniformly distributed within the film. At the same time, the heat treatment further improves the film's density and eliminates defects between the metal-organic polyhedra and the polymer.
[0140] When the feed pressure of Example 4 and Comparative Example 1 was further increased from 2 bar to 20 bar, the changes in permeability and selectivity were as follows: Figure 2 and Figure 3 It can be seen that when metal-organic polyhedra are used as fillers, the He / CH4 selectivity only decreases by 19% ( Figure 2 When metal-organic frameworks are used as fillers, the He / CH4 selectivity decreases by 67%. Figure 3 In contrast, metal-organic polyhedral hybrid matrix membranes exhibited good pressure resistance.
[0141] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.
Claims
1. A high-pressure resistant membrane based on metal-organic polyhedra, characterized in that: It is obtained by using a rigid polymer as the matrix material and doping it with metal-organic polyhedra, wherein the amount of metal-organic polyhedra added accounts for 10 wt% to 50 wt% of the total material.
2. The high-pressure resistant membrane based on metal-organic polyhedra according to claim 1, characterized in that: The rigid polymer is one or more of polybenzimidazole, polyimide, and polyethersulfone.
3. The high-pressure resistant membrane based on metal-organic polyhedra according to claim 2, characterized in that: The metal nodes of the metal-organic polyhedron are one of zirconium-based, iron-based, and rare earth-based, and the metal-organic polyhedron is one of carboxylic acid ligands, nitrogen-containing ligands, phosphate groups, and sulfonate groups.
4. A method for preparing a high-voltage resistant membrane based on metal-organic polyhedra according to any one of claims 1-3, characterized in that: Includes the following steps: S1: Preparation of rigid polymer solution; S2: Mix the metal-organic polyhedron with a rigid polymer solution to obtain a metal-organic polyhedron-polymer casting solution; S3: Prepare a membrane using a metal-organic polyhedron-polymer casting solution; S4: Heat-treat the membrane to obtain a high-pressure resistant membrane based on metal-organic polyhedra.
5. The method for preparing a high-voltage resistant membrane based on a metal-organic polyhedron according to claim 4, characterized in that: In S4, the membrane is placed in a high-temperature tube furnace and heat-treated under a nitrogen or argon atmosphere.
6. A method for preparing a high-voltage resistant membrane based on a metal-organic polyhedron according to claim 4 or 5, characterized in that: The heat treatment temperature is 300-600 ℃.
7. A method for preparing a high-voltage resistant membrane based on a metal-organic polyhedron according to claim 4 or 5, characterized in that: The rigid polymer solution in S1 has a rigid polymer mass fraction of 3-5 wt%, and the solvent used to prepare the rigid polymer solution is an anhydrous aprotic polar solvent.
8. The method for preparing a high-voltage resistant membrane based on a metal-organic polyhedron according to claim 7, characterized in that: The solvent is one of dimethyl sulfoxide and N,N-dimethylacetamide.
9. A method for preparing a high-voltage resistant membrane based on a metal-organic polyhedron according to claim 4 or 5, characterized in that: In S3, film formation is achieved by removing the solvent, and the solvent removal temperature is 80~200 ℃.
10. The application of a high-pressure resistant membrane based on metal-organic polyhedra as described in any one of claims 1-3, or a high-pressure resistant membrane based on metal-organic polyhedra prepared by the preparation method of the high-pressure resistant membrane based on metal-organic polyhedra as described in any one of claims 4-9, in gas separation.