A method for modifying a metal-organic framework membrane and applications thereof
By using high-temperature modifier vapor to assemble supramolecular arrays on the surface of metal-organic framework membranes, the problems of large solvent usage and difficulty in recovery in existing technologies are solved, efficient functional modification and simplified operation procedures are achieved, and the application potential of metal-organic framework membranes is enhanced.
Patent Information
- Application Number
- CN202311184899.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-09-14
- Publication Date
- 2025-10-10
- Estimated Expiration
- 2043-09-14
AI Technical Summary
In the functional modification process of metal-organic framework materials in the existing technology, large amounts of solvents are used and difficult to recover, and a solvent cleaning step is required, resulting in low efficiency.
The vapor generated by high-temperature modifiers is used to assemble supramolecular arrays on the surface of metal-organic framework membranes. The amount of modifiers used is small and can be used multiple times without the need for solvent cleaning. The modification is performed by synthesizing carrier-supported or self-supporting metal-organic framework-based membranes.
It effectively reduces the use of solvents, improves modification efficiency, makes the modifying agent easy to recycle, simplifies the operation process, and enhances the functional modification effect of the membrane material.
Smart Images
Figure CN119607911B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of metal-organic framework membranes, and in particular relates to a modification method of a metal-organic framework membrane and an application thereof. Background Art
[0002] Metal-organic frameworks (MOFs) are a class of porous materials composed of metal ions or ion clusters linked by organic ligands. MOFs possess a rich variety of compositions and structures. Among them, the metal-imidazole ester framework family, exemplified by ZIF-8, represents a significant branch of this family and holds significant potential for application in separations. Post-synthesis modification of MOFs to functionalize them is a key research area. Summary of the Invention
[0003] In view of this, the purpose of the present invention is to provide a modification method for a metal-organic framework membrane and its application. The present invention first prepares a metal-organic framework base membrane, and then uses the vapor generated by the modifier at high temperature to assemble a supramolecular array on the surface of the membrane material. This process does not require a solvent; the amount of modifier used is small, can be used multiple times, and is easy to recycle; and there is no need to clean the base membrane with a solvent after the modification reaction.
[0004] In order to achieve the above object, the present invention provides the following technical solutions:
[0005] A method for modifying a metal-organic framework film comprises the following steps:
[0006] (1) Synthesizing carrier-supported metal-organic framework-based membranes or self-supporting metal-organic framework-based membranes;
[0007] (2) placing the modifying agent in a reaction kettle, placing the carrier-supported metal-organic framework-based membrane or the self-supporting metal-organic framework-based membrane obtained in step (1) on a support and then placing it in the reaction kettle, separating it from the modifying agent, and then reacting at a temperature of 70 to 220° C. for 0.5 to 120 hours to complete the modification of the metal-organic framework membrane;
[0008] (3) Treating the membrane obtained in step (2) in a vacuum environment of 0-5000 Pa for 1 to 180 minutes.
[0009] Based on the above technical solution, further, the stent described in step (1) is a polytetrafluoroethylene stent.
[0010] Based on the above technical solution, further, the metal-organic framework-based membrane described in step (1) includes but is not limited to ZIF-L, ZIF-8, MOF-74 and MIL-53.
[0011] Based on the above technical solution, further, the carrier-supported metal-organic framework-based membrane described in step (1) is synthesized by solvent thermal method, seed secondary growth method, electrochemical method, interface growth method, reverse diffusion method, microflow method, dry powder wiping method, filtration method, hot pressing method, immersion-pulling method, drop coating method, blade coating method, and spin coating method.
[0012] Based on the above technical solution, further, the method for synthesizing the carrier-supported metal-organic framework-based membrane described in step (1) is to mix the metal salt, organic ligand and solvent evenly, stir for 0.5 to 5 hours, centrifuge, wash, and dry to obtain a powder, disperse the powder in the solvent by suction filtration or directly coat the powder onto the carrier.
[0013] Based on the above technical solution, further, the synthesis method of the self-supporting metal-organic framework-based membrane described in step (1) is: mixing the metal salt, organic ligand and solvent evenly, stirring for 0.5 to 5 hours, centrifuging, washing, and drying to obtain a powder, and the powder is pressed into a tablet to obtain a self-supporting metal-organic framework-based membrane.
[0014] Based on the above technical solution, further, in step (1), the molar ratio of metal, organic ligand, and solvent is 1:0.1-20:500-20000.
[0015] Based on the above technical solution, further, the support carrier described in step (1) is a stainless steel mesh or a porous alumina carrier.
[0016] Based on the above technical solution, further, the modifier described in step (2) is benzoic acid and functionalized derivatives thereof, terephthalic acid and functionalized derivatives thereof, imidazole and functionalized derivatives thereof, 1,2,3-triazole and derivatives thereof, 1,2,4-triazole and derivatives thereof, tetrazole and derivatives thereof, pyrazine and derivatives thereof, piperazine and derivatives thereof, pyridine and derivatives thereof, piperidine and derivatives thereof, pyrimidine and derivatives thereof, porphyrin and derivatives thereof, adenine, thiophene and derivatives thereof, tannic acid, iodine and iodide.
[0017] Based on the above technical solution, further, the mass ratio of the modifier described in step (2) to the metal-organic framework base film is 50,000 to 100.
[0018] Based on the above technical solution, further, the distance between the modifier described in step (2) and the metal-organic framework base film is 1 to 10 cm.
[0019] Another aspect of the present invention provides a metal-organic framework film prepared by the above modification method.
[0020] The present invention also provides application of the metal-organic framework membrane in separation of mixed gases or mixed liquids.
[0021] Based on the above technical solution, further, the mixed gas separation includes H2 / CO2 separation, H2 / CH4 separation, CH4 / CO2 separation, CO2 / N2 separation, and ethylene / ethane separation.
[0022] Based on the above technical solution, further, the mixed liquid separation includes alcohol / water separation and methanol / chloroform separation.
[0023] Compared with the prior art, the advantages of the present invention are:
[0024] (1) Compared with the solvent method, the modification method of the present invention greatly reduces the use of solvents.
[0025] (2) The amount of modifying agent used is small, it can be used multiple times, and is easy to recycle; there is no need to clean the base film with solvent after the modification reaction. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the embodiments of the present invention, the drawings related to the embodiments are briefly introduced below.
[0027] Figure 1 is a schematic diagram of a polytetrafluoroethylene stent.
[0028] Figure 2 1 is the X-ray diffraction pattern of the triazole supramolecule-ZIF-L composite film and ZIF-L in Example 1.
[0029] Figure 3 These are SEM images of ZIF-L (a) and triazole supramolecular-ZIF-L composite membrane (b) in Example 1.
[0030] Figure 4 This is a graph showing the separation performance of the composite membrane in Example 2.
[0031] Figure 5 This is the X-ray diffraction pattern of the self-supporting composite membrane material in Example 3.
[0032] Figure 6 is the self-supporting composite membrane material in Example 3 1 H NMR spectrum.
[0033] Figure 7 These are SEM images of the deep layer (a) and surface (b) of the self-supporting composite membrane material in Example 3. DETAILED DESCRIPTION
[0034] The following specific examples further illustrate the present invention and should not be construed as limiting the present invention in any form.
[0035] Example 1 Preparation of triazole supramolecular layer-ZIF-L composite membrane by filtration transfer method
[0036] Firstly, the synthetic metal raw material zinc nitrate hexahydrate (Zn 2+ ) and the ligand raw material 2-methylimidazole (mim) were dissolved in the aqueous solvent, and the molar ratio of each substance was Zn 2+ :mim:H2O = 1:8:2200, and the mixture was uniformly mixed at room temperature. A milky white turbidity was immediately generated in the mixed solution, and the mixture was stirred at room temperature for 1 h. The product was collected by centrifugation (15000 rpm, 10 min), washed with water for 3 times, and dried at 60°C to prepare ZIF-L powder (MOF).
[0037] 25 mg of the prepared powder was redispersed in 400 mL of water, and was filtered onto a stainless steel mesh (air permeability = 9.75 L / dm 2 / min) carrier to complete the transfer of the MOF to the carrier, and a carrier-supported metal-organic framework membrane (2.5 mg / cm 3 ) was obtained. 1.5 g of 3-methyl-1,2,4-triazole ligand was added to the bottom of the reaction kettle, and the carrier-supported metal-organic framework membrane was placed on a polytetrafluoroethylene support and then placed in the reaction kettle. Subsequently, the reaction kettle was placed in an oven at 110°C for 6 h, and the metal-organic framework membrane was subjected to supramolecular assembly by using the vapor generated by the modifier at high temperature.
[0038] Figure 2 The X-ray diffraction pattern of the triazole supramolecular-ZIF-L composite membrane prepared by reacting at 110°C for 6 h and ZIF-L, and the X-ray diffraction pattern confirmed the successful assembly of the amorphous supramolecular layer on the surface of the membrane.
[0039] Figure 3 The SEM images of ZIF-L and the triazole supramolecular-ZIF-L composite membrane prepared by reacting at 110°C for 6 h, and the SEM images prove that the originally elliptical ZIF-L grains are covered with a smooth amorphous supramolecular layer.
[0040] The prepared triazole supramolecular-ZIF-L composite membrane was used for H2 / CO2 mixed gas separation performance test. At 25°C, the membrane assembly was sealed by silicone rubber, the raw material side was 50 mL of H2 and 50 mL of CO2 mixed gas, and the permeation side was 50 mL / min of Ar gas as tail gas to eliminate the concentration polarization on the permeation side of the membrane. The triazole supramolecular layer has a certain selectivity (19.6) for H2 / CO2, and the hydrogen permeation rate is 960 GPU, which proves that the triazole supramolecular-ZIF-L composite membrane has application potential for gas separation.
[0041] Example 2 Hand-coating MOF transfer method for preparation of triazole supramolecular layer-ZIF-L composite membrane
[0042] First, the synthetic metal raw material zinc nitrate hexahydrate (abbreviated as Zn 2+ ) and the ligand raw material 2-methylimidazole (abbreviated as mim) are dissolved in water solvent, wherein the molar ratio of each substance is Zn 2+ :mim:H2O=1:8:2200, mix evenly at room temperature, milky turbidity is immediately generated in the mixed solution, stir at room temperature for 1 hour, centrifuge (15000 rpm, 10 min) to collect the product, wash with water three times, and dry at 60℃ to prepare ZIF-L powder.
[0043] The prepared powder was applied by hand to a stainless steel mesh (air permeability = 9.75 L / dm 2 / min) carrier, the transfer of MOF to the carrier was completed, and the carrier-supported metal-organic framework membrane (1 mg / cm 3 ); 1.5 g of 3-methyl-1,2,4-triazole ligand was added to the bottom of the reactor, and the carrier-supported metal-organic framework membrane was placed on a polytetrafluoroethylene bracket and then placed in the reactor. The reactor was then placed in an oven at 110°C for 6 hours, and the metal-organic framework membrane was supramolecularly assembled using the vapor generated by the modifier at high temperature.
[0044] The prepared triazole supramolecular-ZIF-L composite membrane was used to test the H2 / CO2 mixed gas separation performance, and the test conditions were the same as in Example 1. At the same time, the H2 / CH4 and CH4 / CO2 separation performance tests were carried out, and the test conditions were the same as in Example 1.
[0045] Figure 4 This is the separation performance diagram of the triazole supramolecular-ZIF-L composite membrane. It has excellent H2 / CO2 separation selectivity, as high as 383.3, and also has a high hydrogen permeability (1739.7GPU).
[0046] Example 3 Preparation of a self-supporting MOF triazole supramolecular layer-ZIF-L composite membrane
[0047] First, the synthetic metal raw material zinc nitrate hexahydrate (abbreviated as Zn 2+ ) and the ligand raw material 2-methylimidazole (abbreviated as mim) are dissolved in water solvent, wherein the molar ratio of each substance is Zn 2+ :mim:H2O=1:8:2200, mix evenly at room temperature, milky turbidity is immediately generated in the mixed solution, stir at room temperature for 1 hour, centrifuge (15000 rpm, 10 min) to collect the product, wash with water three times, and dry at 60℃ to prepare ZIF-L powder.
[0048] The prepared powder is pressed into a disc with a diameter of 18 mm and a thickness of about 0.8 mm to obtain a self-supporting MOF film material; 1.5 g of 3-methyl-1, 2, 4-triazole ligand is added to the bottom of a reaction kettle, the self-supporting MOF film material is placed on a polytetrafluoroethylene support and then placed in the reaction kettle, and then the reaction kettle is placed in an oven at 110°C for 6 h, and the metal-organic framework film is subjected to supramolecular assembly by using the vapor generated by the modifier at high temperature.
[0049] Figure 5 For the X-ray diffraction pattern of the prepared self-supporting MOF composite film material, it can be seen that the diffraction pattern of the material is still the characteristic spectrum of an amorphous state.
[0050] Figure 6 For the X-ray diffraction pattern of the prepared self-supporting MOF composite film material, it can be seen that the diffraction pattern of the material is still the characteristic spectrum of an amorphous state. 1 The H NMR spectrum shows that the material has the characteristic peak position of the triazole layer.
[0051] Figure 7 For the SEM image of the surface and deep layer of the self-supporting MOF triazole supramolecular layer-ZIF-L composite film material, it can be seen that the characteristic morphology of ZIF-L can still be distinguished in the material, and the outer layer is a smooth supramolecular layer.
[0052] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; the technical solutions described in the above examples are modified, or some or all of the technical features are replaced; these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A method for modifying a metal-organic framework membrane, characterized in that: The steps include: (1) Synthesizing carrier-supported metal-organic framework-based membranes or self-supporting metal-organic framework-based membranes; (2) placing the modifier in a reactor, placing the carrier-supported metal-organic framework-based membrane or the self-supporting metal-organic framework-based membrane obtained in step (1) on a support and then placing it in the reactor, separating it from the modifier, and then reacting at a temperature of 70 to 220° C. for 0.5 to 120 hours to complete the modification of the metal-organic framework membrane; (3) treating the membrane obtained in step (2) in a vacuum environment of 0-5000 Pa for 1-180 min; The metal-organic framework-based membrane described in step (1) includes ZIF-L, ZIF-8, MOF-74 and MIL-53; The modifying agent in step (2) is 1,2,3-triazole and its derivatives or 1,2,4-triazole and its derivatives.
2. The modification method according to claim 1, characterized in that The carrier-supported metal-organic framework-based membrane described in step (1) is synthesized by a solvent thermal method, a seed crystal secondary growth method, an electrochemical method, an interfacial growth method, a reverse diffusion method, a microfluidic method, a dry powder rubbing method, a filtration method, a hot pressing method, a dip-pulling method, a drop coating method, a blade coating method or a spin coating method.
3. The modification method according to claim 2, characterized in that The method for synthesizing the carrier-supported metal-organic framework-based membrane described in step (1) is to uniformly mix the metal salt, organic ligand and solvent, stir for 0.5 to 5 hours, centrifuge, wash and dry to obtain powder, disperse the powder in the solvent and filter it by suction or directly coat the powder on the carrier.
4. The modification method according to claim 1, wherein The method for synthesizing the self-supporting metal-organic framework-based membrane described in step (1) is as follows: uniformly mixing the metal salt, the organic ligand and the solvent, stirring for 0.5 to 5 hours, centrifuging, washing, and drying to obtain a powder, and then tableting the powder to obtain the self-supporting metal-organic framework-based membrane.
5. The modification method according to claim 3 or 4, characterized in that In step (1), the molar ratio of metal, organic ligand, and solvent is 1:0.1-20:500-20000; the support carrier is a stainless steel mesh or a porous alumina carrier.
6. The modification method according to claim 1, wherein The mass ratio of the modifier to the metal-organic framework base membrane in step (2) is 50,000-100; the distance between the modifier and the metal-organic framework base membrane is 1-10 cm.
7. A metal-organic framework membrane prepared by the modification method according to any one of claims 1 to 6.
8. Use of the metal-organic framework membrane according to claim 7 in mixed gas separation or mixed liquid separation.
9. The use according to claim 8, characterized in that The mixed gas separation includes H2 / CO2 separation, H2 / CH4 separation, CH4 / CO2 separation, CO2 / N2 separation, and ethylene / ethane separation; the mixed liquid separation includes alcohol / water separation and methanol / chloroform separation.