Mixed matrix membrane as well as preparation method and application thereof

Abstract

The invention relates to the technical field of membrane separation materials, in particular to a mixed matrix membrane and a preparation method and application thereof. The mixed matrix membrane comprises: (1) a polymer functional membrane; (2) a base film for supporting the polymer functional film; a polymer in the polymer functional film comprises a polymer with a structure as shown in a formula (a), in the formula (a), R0 is an alkylene chain, R1 is a polysiloxane group, R2 is alkyl or hydrogen, and m is equal to 1-20. According to the present invention, the functional membrane prepared from the polymer having the structure (a) is used, and the structure of the polysiloxane is designed and optimized, such that the mixed matrix membrane has excellent organic solvent tolerance and organic solvent pervaporation separation property, and the interfacial compatibility between the polymer and the porous filler can be improved.

Description

Technical Field

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

[0002] A membrane is a structure capable of separating one or more substances from a liquid, vapor, or gas. It acts as a selective barrier by allowing some substances to pass through (i.e., permeate or permeate stream) while preventing others from passing through (i.e., residue or residue stream). Currently, polymer membranes are used in a wide range of fields, including industry, pharmaceuticals, and medicine, for precision filtration. In these applications, membrane separation methods are becoming increasingly important because they offer the advantage of allowing the substances to be separated to be free from thermal stress or even damage. Membrane separation methods can be used to remove or separate large molecules, and many further applications are found in the beverage industry, biotechnology, water treatment, and wastewater treatment technologies.

[0003] Existing polysiloxane separation membranes are characterized by low cost and ease of processing. However, a "trade-off" effect exists between their permeability and selectivity: high permeability corresponds to low selectivity, and vice versa. Doping polysiloxane matrix membranes with porous materials such as MOFs to prepare mixed matrix membranes is an effective method to improve the separation performance of polysiloxane membranes. Currently, the preparation process of MOF-doped polysiloxane mixed matrix membranes generally involves dispersing hydroxyl-terminated polydimethylsiloxane (PDMS) and MOF filler particles in an organic solvent, stirring to form a casting solution, coating it onto a substrate to form a uniform liquid film, and then curing and crosslinking to obtain the separation membrane. This process has three drawbacks: first, the interfacial compatibility between hydroxyl-terminated PDMS and MOF particles is poor; second, solvent evaporation during curing leads to MOF particle sedimentation and aggregation; and third, the dispersion of MOF particles within the membrane is poor, resulting in poor repeatability of performance between different batches of samples. Consequently, the pervaporation separation performance of the separation membrane for organic solvents is not ideal. Furthermore, existing polymer membranes, including the aforementioned membranes, are not suitable for effectively separating organic solvents from aqueous solutions.

[0004] Therefore, there is an urgent need to develop a separation membrane that can significantly improve the pervaporation separation performance of organic solvents. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem of poor pervaporation separation performance of organic solvents in the existing mixed matrix membranes, and to provide a mixed matrix membrane, its preparation method, and its application. This mixed matrix membrane exhibits excellent pervaporation separation performance for organic solvents.

[0006] To achieve the above objectives, the first aspect of the present invention provides a hybrid matrix membrane comprising: (1) a polymer functional membrane; and (2) a base membrane for supporting the polymer functional membrane.

[0007] The polymer in the polymer functional membrane comprises a polymer having a structure as shown in formula (a):

[0008]

[0009] In formula (a), R0 is an alkylene chain, R1 is a polysiloxane alkyl group, R2 is a hydrocarbon group or hydrogen, and m = 1-20.

[0010] The second aspect of the present invention provides a method for preparing the hybrid matrix membrane described in the first aspect. The preparation method includes the following steps: S1, preparing a casting solution containing a polymeric monomer and a photoinitiator; S2, coating the casting solution onto one side of the substrate membrane surface to form a liquid film, and initiating a polymerization reaction to solidify the liquid film on the substrate membrane surface.

[0011] A third aspect of the present invention provides an application of the mixed matrix membrane described in the first aspect in the pervaporation separation of organic solvents in aqueous solutions.

[0012] Through the above technical solution, the present invention has the following advantages:

[0013] This invention uses a functional membrane made of a polymer with structure (a). By designing and optimizing the structure of polysiloxane, the mixed matrix membrane has excellent organic solvent resistance and organic solvent pervaporation separation properties, and can improve the interfacial compatibility between the polymer and the porous filler. Preferably, MOF material is filled on the functional membrane, and the polymer and MOF material have significant synergistic properties, which further improves the separation effect of the mixed matrix membrane.

[0014] The preferred preparation method of the present invention includes in-situ coordination and crystallization growth of MOF particle precursors within a polysiloxane matrix, which further improves the organic solvent resistance and pervaporation separation performance of the mixed matrix membrane. Attached Figure Description

[0015] Figure 1 These are scanning electron microscope (SEM) images of the hybrid matrix membrane prepared in Example 1 of this invention; wherein, Figure 1 (a) is a scanning electron microscope image of the surface of the hybrid matrix film. Figure 1 (b) is a cross-sectional scanning electron microscope image of the mixed matrix membrane. Detailed Implementation

[0016] 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.

[0017] The present invention provides a hybrid matrix membrane comprising: (1) a polymer functional membrane; and (2) a base membrane for supporting the polymer functional membrane.

[0018] The polymer in the polymer functional membrane comprises a polymer having a structure as shown in formula (a):

[0019]

[0020] In formula (a), R0 is an alkylene chain, R1 is a polysiloxane alkyl group, R2 is a hydrocarbon group or hydrogen, and m = 1-20.

[0021] This invention uses a functional membrane made of a polymer with structure (a). By designing and optimizing the structure of polysiloxane, the mixed matrix membrane has excellent organic solvent resistance and organic solvent pervaporation separation properties, and can improve the interfacial compatibility between the polymer and the porous filler. Preferably, MOF material is filled on the functional membrane, and the polymer and MOF material have significant synergistic properties, which further improves the separation effect of the mixed matrix membrane.

[0022] According to a preferred embodiment of the present invention, in formula (a), R0 is a C1-10, preferably C3-6, alkylene chain. By adopting the aforementioned preferred embodiment, the separation effect of the mixed matrix membrane on organic solvents can be further improved.

[0023] According to a preferred embodiment of the present invention, in formula (a), R1 is a polysiloxane with a degree of polymerization of 10-500, preferably C100-300. By adopting the aforementioned preferred embodiment, the separation effect of the mixed matrix membrane on organic solvents can be further improved.

[0024] According to a preferred embodiment of the present invention, in formula (a), R2 is a C1-C3 hydrocarbon group or hydrogen. By adopting the aforementioned preferred embodiment, the separation effect of the mixed matrix membrane on organic solvents can be further improved.

[0025] According to a preferred embodiment of the present invention, the number average molecular weight of the polymeric monomers used to polymerize the polymer having the structure shown in formula (a) is 8000-60000 g / mol, preferably 20000-100000 g / mol. By adopting the aforementioned preferred embodiment, the separation effect of the mixed matrix membrane on organic solvents can be further improved.

[0026] According to a preferred embodiment of the present invention, in formula (a), m = 5-15. By adopting the aforementioned preferred embodiment, the separation effect of the mixed matrix membrane on organic solvents can be further improved.

[0027] In this invention, the water contact angle of the mixed matrix membrane of the polymer material having the structure described in formula (a) of this invention is 110-127°, preferably 115-127°. Here, the water contact angle refers to the angle θ between the tangent line at the solid-liquid interface drawn at the liquid-solid phase junction and the solid-liquid interface line on the liquid side.

[0028] In this invention, when the lateral pressure is 100 Pa, the permeation flux of the polymer material mixed matrix membrane having the structure described in formula (a) of this invention for separating a 5.0 wt% acetone aqueous solution at 40-80 °C is 950-2600 g m. -2 h -1 The preferred value is 1500-2600g m -2 h -1 The separation factor is 23-35, preferably 26-30; the permeation flux for separating 1.5wt% butanol aqueous solution at 40-60℃ is 350-780 g m -2 h -1 Preferably, it is 500-650g m -2 h -1 The separation factor is 18-25, preferably 20-22.

[0029] According to the present invention, the polymer functional film optionally contains at least one selected from polyalkyl acrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyamide, polyimide, polyacrylonitrile, polyaniline, polypyrrole and polyetheretherketone.

[0030] According to a preferred embodiment of the present invention, the content of the polymer having the structure shown in formula (a) accounts for at least 50% of the total mass of the polymer functional membrane, for example, it can be 60%, 70%, 80%, 90%, or 100%, preferably 80-100%. By adopting the aforementioned preferred embodiment, the separation effect of the mixed matrix membrane on organic solvents can be further improved.

[0031] In this invention, the functional membrane can be filled with a variety of porous inorganic materials, such as organic framework materials and / or carbon-based nanomaterials. The organic framework material is selected from at least one of metal-organic framework materials, covalent organic framework materials, and hydrogen-bonded organic framework materials; the carbon-based nanomaterial is selected from at least one of graphene, quantum dots, and carbon nanotubes.

[0032] According to a preferred embodiment of the present invention, the polymer functional membrane is filled with 1-70 wt% of the total mass of the polymer functional membrane, preferably 5-50 wt% of MOF, for example, the content of MOF in the polymer functional membrane is 1 wt%, 2 wt%, 5 wt%, 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, etc.

[0033] According to a preferred embodiment of the present invention, the organic ligand of the MOF particle is selected from imidazole ligands and / or terephthalic acid ligands, and the metal ion is selected from at least one of transition metal ions.

[0034] In this invention, imidazole ligands can be conventional choices in the art, as long as they can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the imidazole ligand is selected from at least one of 2-methylimidazole, 2-formylimidazole, benzimidazole, 2-nitroimidazole, and 4-chloro-5-nitroimidazole.

[0035] In this invention, terephthalic acid ligands can be conventional choices in the art, as long as they can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the terephthalic acid ligand is selected from at least one of phthalic acid, 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, and 2-fluoroterephthalic acid.

[0036] According to a preferred embodiment of the present invention, the transition metal ion includes at least one of Group IB metal ions, Group IIB metal ions, Group VIII metal ions, and Group IVB metal ions, preferably including at least one of zinc ions, cobalt ions, iron ions, copper ions, and zirconium ions.

[0037] According to a preferred embodiment of the present invention, the metal-organic framework material includes at least one of ZIF-8, ZIF-67, ZIF-7, ZIF-90, MOF-5, Cu(BDC), NH2-UiO-66, UiO-66, copper ion-doped UiO-66, copper ion-doped NH2-UiO-66, and MIL-53.

[0038] In this invention, there are no special requirements for the thickness of the base membrane in the mixed matrix membrane, as long as the purpose of this invention can be achieved. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the thickness of the base membrane in the mixed matrix membrane is 10-3000 μm, for example, it can be 10 μm, 50 μm, 100 μm, 200 μm, 500 μm, 1000 μm, 2000 μm, or 3000 μm, preferably 50-200 μm.

[0039] In this invention, there are no special requirements for the thickness of the polymer functional membrane in the mixed matrix membrane, as long as the purpose of this invention can be achieved. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the thickness of the polymer functional membrane in the mixed matrix membrane is 0.5-50 μm, for example, it can be 0.5 μm, 1 μm, 2 μm, 10 μm, 20 μm, 30 μm, 40 μm, or 50 μm, preferably 2-20 μm.

[0040] In this invention, the material of the base membrane can be a conventional choice in the art, as long as it can achieve the purpose of this invention. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the material of the base membrane comprises a porous material, preferably comprising at least one of polyvinylidene fluoride, polyacrylonitrile, polytetrafluoroethylene, polyethersulfone, alumina and silicon oxide.

[0041] In this invention, the base membrane is a layered composite membrane of a porous material layer / supporting material layer, which is a composite layered structure. It includes a supporting material layer and a porous base membrane layer covering one side of the supporting material layer (the other side of the porous base membrane layer is provided with a polymer functional membrane layer). The supporting material layer includes non-woven fabric.

[0042] Those skilled in the art should understand that when the substrate is a base film composite substrate, the layered composite membrane with a composite layered structure sequentially includes a support material layer, a porous base film layer, and a polymer functional film layer.

[0043] In this invention, there are no particular requirements for the preparation method of the hybrid matrix membrane, as long as the purpose of this invention can be achieved. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the preparation method of the hybrid matrix membrane includes the following steps:

[0044] S1. Prepare a casting solution containing polymer monomers and photoinitiators;

[0045] S2. The casting solution is coated on one side of the substrate film surface to form a liquid film, which triggers a polymerization reaction to solidify the liquid film on the substrate film surface.

[0046] According to a preferred embodiment of the present invention, a porous inorganic material may optionally be filled in step S1.

[0047] It should be noted that when doping MOF materials, the preparation method includes the following steps: S1, preparing a casting solution containing an organic ligand of MOF, a polymerizable monomer, and a photoinitiator; S2, coating the casting solution onto one side of the substrate membrane surface to form a liquid film, initiating a polymerization reaction to solidify the liquid film on the substrate membrane surface, obtaining a precursor; S3, contacting the precursor with a MOF metal ion source solution for reaction. By adopting the aforementioned preferred preparation method, the dispersibility of MOF materials in the matrix membrane can be significantly improved, greatly enhancing the separation performance of the mixed matrix membrane.

[0048] The method of preparing the casting solution in step S1 can be a conventional method in the art. According to a preferred embodiment of the present invention, step S1 includes: first dispersing the MOF organic ligand in a polymer monomer solution, then adding a photoinitiator, and then dynamically mixing, such as mechanical stirring, to obtain the casting solution.

[0049] The curing method in step S2 can be a conventional method in the art. Step S2 includes: vacuum degassing the prepared casting liquid for 5-15 minutes, then coating it on the surface of a porous substrate membrane to form a liquid film, drying it, irradiating the liquid film with ultraviolet light, and curing it to obtain the film containing the dense layer of organic ligands.

[0050] In this invention, the mixed matrix membrane may be rinsed after preparation, and the rinsing agent may be, for example, water.

[0051] According to a preferred embodiment of the present invention, the conditions for the polymerization reaction include: a temperature of 25-60°C, preferably 30-45°C, and more preferably 30-35°C.

[0052] In this invention, the polymerization reaction time is adjusted according to the reaction temperature and other conditions. According to a preferred embodiment of this invention, the polymerization reaction time is 3-60 min, preferably 10-30 min.

[0053] In this invention, the atmosphere of the polymerization reaction is not particularly limited and can be an air atmosphere, with photocrosslinking free polymerization initiated by ultraviolet light radiation. Those skilled in the art should understand that during the preparation process, the monomers are polymerized under ultraviolet light radiation. The photoinitiator can absorb energy of a certain wavelength in the ultraviolet region (200-420 nm), generating free radicals, thereby initiating carbon-carbon double bond polymerization and crosslinking, causing the casting solution to solidify into a dense film.

[0054] According to a preferred embodiment of the present invention, the conditions for the contact reaction include a temperature of 25-150°C, preferably 35-80°C.

[0055] In this invention, the contact reaction time is adjusted according to the contact temperature and other conditions. According to a preferred embodiment of this invention, the contact time is 0.5-24h, preferably 3-12h, and more preferably 5-10h.

[0056] In this invention, the coating method is not particularly limited and can be a conventional coating method in the art, such as dip coating, drool coating, scraping coating, spin coating, etc.

[0057] In this invention, there is no particular limitation on the content of each substance in the casting solution. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of MOF organic ligand, polymer monomer, photoinitiator and first solvent in the casting solution is (0-1):(1-200):(0.01-1):(2:2000), preferably (0.5-1):(2-50):(0.02-0.5):(4-500).

[0058] In this invention, the photoinitiator can be a conventional choice in the art, as long as it can initiate a reaction. The following is an illustrative description, but it does not limit the scope of the invention. The photoinitiator is at least one of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxy-cyclohexylphenyl ketone, benzophenone, and benzoin ether.

[0059] In this invention, there is no particular limitation on the content of each substance in the casting solution. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of the metal salt to the second solvent in the MOF metal ion source solution is 1:(10-1000), preferably 1:(20-500).

[0060] In this invention, the types of the first solvent and the second solvent can be conventional choices in the art, as long as they can dissolve the substance to be dissolved. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the first solvent and the second solvent are each independently selected from at least one of methanol, ethanol, N,N-dimethylformamide, chloroform, tetrahydrofuran, dichloromethane and n-heptane, preferably dichloromethane and / or n-heptane.

[0061] This invention provides an application of the aforementioned mixed matrix membrane in the pervaporation separation of organic solvents in aqueous solutions.

[0062] In this invention, there is no particular limitation on the concentration of the organic solvent in the aqueous solution of the organic solvent. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the aqueous solution of the organic solvent is an aqueous solution of an organic solvent with a mass concentration of not more than 45 wt%.

[0063] In this invention, the organic solvent can be a conventional choice in the art. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the organic solvent is selected from at least one of alcohols, aldehydes, ketones, ethers, and optionally esters and / or organic hydrocarbons.

[0064] In this invention, a JC2000D3 contact angle measuring instrument (Shanghai Zhongchen Digital Technology Equipment Co., Ltd.) is used to measure the water contact angle.

[0065] In this invention, the evaluation method for pervaporation separation performance is as follows:

[0066] The prepared mixed matrix membrane was sealed in a membrane tank, with the feed temperature controlled between 25-80℃ and the permeate-side pressure maintained below 300 Pa. Before formal sampling and analysis, the membrane separation unit was run for at least 45 minutes to allow the system to reach equilibrium, and the permeate was collected using a cryogenic cold trap. The feed concentration and permeate mass concentration were determined by gas chromatography. Taking acetone-water solution as an example, the separation performance was calculated as follows.

[0067] The pervaporation membrane flux J is determined by the following formula:

[0068]

[0069] Where W is the mass of the feed solution collected on the permeate side (g), t is the test time (h), and A is the effective membrane area (m²). 2 ),

[0070] The separation factor β is determined by the following formula:

[0071]

[0072] y B and x B The values ​​are the mass fractions (wt%) of acetone in the feed and permeate sides, respectively. A and x A The concentrations of water on the feed side and the permeate side are (wt%), respectively.

[0073] The present invention will be described in detail below through embodiments. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0074] Example 1

[0075] (1) Preparation of casting solution: 2.0g of polydimethylsiloxane methacrylate with a number average molecular weight of about 50,000 (R0 is a C3 alkylene chain, R1 is a polydimethylsiloxane with a degree of polymerization of 100, R2 is methyl, catalog number Q-0155658, Xi'an Qiyue Biotechnology Co., Ltd.), 0.5g of 2-methylimidazole, 0.05g of 2-hydroxy-2-methyl-1-phenylpropanone and 2.0g of dichloromethane were mixed and stirred at 500rpm for 0.5h to obtain a uniformly dispersed casting solution.

[0076] (2) Coating: After vacuum degassing the casting solution for 5-15 minutes, coat it evenly on one side of a 50μm thick polyvinylidene fluoride (PVDF) / nonwoven base film.

[0077] (3) Curing: The liquid film was dried at 30°C for 5 hours and then cured by UV irradiation for 10 minutes. An organic film with a thickness of 2.0 μm containing 2-methylimidazole (MOF organic ligand) on the surface was obtained on the base film, with a degree of polymerization m of 6.

[0078] (4) Crystallization: Dissolve 1.0 g of zinc nitrate hexahydrate in 40 g of deionized water, immerse the material obtained in step (3) in the above zinc nitrate aqueous solution, and treat it at 35 °C for 6 h. Then rinse three times with deionized water to obtain a mixed matrix film doped with 24.5 wt% ZIF-8 particles.

[0079] The contact angle of the mixed matrix membrane obtained in step (4) was tested, and the water contact angle was found to be 122°. Acetone was then separated from the membrane by pervaporation. With an acetone concentration of 5.0 wt% on the feed side, a feed temperature of 70°C, and a permeation pressure of 100 Pa, the permeation flux of the mixed matrix membrane was measured to be 1750 g m³ / s. -2 h -1 The separation factor is 30.

[0080] Figure 1 (a) is a scanning electron microscope image of the surface of the hybrid matrix film, which shows that the film surface is dense and continuous, and no pinhole-shaped defects were found.

[0081] Figure 1 (b) is a cross-sectional scanning electron microscope image of the hybrid matrix membrane, which shows that the membrane cross-section is dense and continuous, and the MOF nanoparticles are uniformly dispersed in the polymer layer.

[0082] Example 2

[0083] (1) Preparation of casting solution: 4.0g of polymethyl octylsiloxane methacrylate with a number average molecular weight of about 70,000, 4.0g of 2-methylimidazole, 0.04g of 2-hydroxy-2-methyl-1-phenylpropanone, and 8.0g of n-heptane were mixed and stirred at 500rpm for 1.0h to obtain a uniformly dispersed casting solution.

[0084] (2) Coating: After vacuum degassing the casting solution for 10 minutes, coat it evenly on one side of a 70μm thick polyethersulfone / nonwoven base film.

[0085] (3) Curing: The liquid film was dried at 35°C for 3 hours and then cured by UV irradiation for 20 minutes to obtain an organic film with a thickness of 5.0 μm containing 2-methylimidazole (MOF organic ligand) on the surface and a degree of polymerization m of 8.

[0086] (4) Crystallization: Dissolve 1.5g of cobalt nitrate hexahydrate in 150g of deionized water, immerse the material obtained in step (3) in the above cobalt nitrate aqueous solution, and treat it at 40℃ for 12h. Then rinse three times with deionized water to obtain a mixed matrix film doped with 52.5wt% ZIF-67 particles.

[0087] The contact angle of the mixed matrix membrane obtained in step (4) was tested, and the water contact angle was found to be 121°. Acetone was then separated from the membrane by pervaporation. With an acetone concentration of 5.0 wt% on the feed side, a feed temperature of 60°C, and a permeation pressure of 100 Pa, the permeation flux of the mixed matrix membrane was measured to be 2550 g m³ / s. -2 h -1 The separation factor is 26.

[0088] Example 3

[0089] (1) Preparation of casting solution: 1.0g of polydimethylsiloxane methacrylate with a number average molecular weight of about 100,000, 1.0g of terephthalic acid, 0.6g of 1-hydroxy-cyclohexylphenyl ketone, and 10.0g of dichloromethane were mixed and stirred at 500rpm for 2.0h to obtain a uniformly dispersed casting solution.

[0090] (2) Coating: After vacuum degassing the casting solution for 8 minutes, coat it evenly on one side of a 60μm thick polyethersulfone / nonwoven base film.

[0091] (3) Curing: The liquid film was dried at 30°C for 3 hours and then cured by UV irradiation for 15 minutes. An organic film with a thickness of 8 μm containing terephthalic acid (MOF organic ligand) was obtained on the substrate film, with a degree of polymerization m of 6.

[0092] (4) Crystallization: Dissolve 0.8 g of zirconium tetrachloride in 100 g of N,N-dimethylformamide (DMF), immerse the material obtained in step (3) in the above zirconium tetrachloride solution, and treat it at 85 °C for 12 h. Then rinse three times with DMF to obtain a mixed matrix film doped with 65.2 wt% UiO-66 particles.

[0093] The contact angle of the mixed matrix membrane obtained in step (4) was tested, and the contact angle of water was found to be 119°. Butanol was then separated from the membrane via pervaporation. With a butanol concentration of 1.5 wt% on the feed side, a feed temperature of 50°C, and a permeation pressure of 100 Pa, the permeation flux of the mixed matrix membrane was measured to be 650 g m³ / s. -2 h -1 The separation factor is 22.

[0094] Example 4

[0095] Same as Example 3, except that:

[0096] (4) Crystallization: Replace zirconium tetrachloride with aluminum chloride solution to obtain a mixed matrix film doped with MIL-53 particles of equal mass content.

[0097] The contact angle of the mixed matrix membrane obtained in step (4) was tested, and the water contact angle was found to be 110°. Butanol was then separated from the membrane via pervaporation. With a butanol concentration of 1.5 wt% on the feed side, a feed temperature of 60°C, and a permeation pressure of 100 Pa, the permeation flux of the mixed matrix membrane was measured to be 680 g / m³. -2 h -1 The separation factor is 18.

[0098] Example 5

[0099] Same as Example 1, except that:

[0100] (1) When preparing the casting solution, 2-methylimidazole is replaced with 2-fluoroterephthalic acid.

[0101] The contact angle was tested and found to be 112° for water. Acetone was then separated from the membrane via pervaporation. With an acetone concentration of 5.0 wt% on the feed side, a feed temperature of 70°C, and a permeation pressure of 100 Pa, the permeation flux of this mixed matrix membrane was measured to be 980 g / m³. -2 h -1 The separation factor is 24.

[0102] Example 6

[0103] Same as Example 1, except that:

[0104] The added polydimethylsiloxane methacrylate has a number-average molecular weight of approximately 8000. The contact angle of the obtained mixed matrix membrane was tested, and the water contact angle was found to be 115°. Acetone was then separated from the membrane via pervaporation. With an acetone concentration of 5.0 wt% on the feed side, a feed temperature of 70°C, and a permeation pressure of 100 Pa, the permeation flux of this mixed matrix membrane was measured to be 1340 g / m³. -2 h -1 The separation factor is 28.

[0105] Example 7

[0106] Same as Example 1, except that:

[0107] In step (1), 2.0g of polydimethylsiloxane methacrylate is replaced with 1.5g of polydimethylsiloxane methacrylate and 0.5g of methyl methacrylate.

[0108] The contact angle of the obtained mixed matrix membrane was tested, and the water contact angle was found to be 115°. Acetone was then separated from the membrane via pervaporation. With an acetone concentration of 5.0 wt% on the feed side, a feed temperature of 70°C, and a permeation pressure of 100 Pa, the permeation flux of the mixed matrix membrane was measured to be 1300 g m³ / s. -2 h -1 The separation factor is 26.

[0109] Example 8

[0110] Same as Example 3, except that terephthalic acid is not added in step (1).

[0111] The contact angle of the obtained separation membrane was tested, and the contact angle with water was found to be 116°. The membrane was then used for pervaporation separation of butanol. With a butanol concentration of 1.5 wt% on the feed side, a feed temperature of 60°C, and a permeation pressure of 100 Pa, the permeation flux of this mixed matrix membrane was measured to be 450 g / m³. -2 h -1 The separation factor is 18.

[0112] Example 9

[0113] Similar to Example 3, except that in step (4), the material obtained in step (3) is impregnated in 100g of N,N-dimethylformamide (DMF).

[0114] The contact angle of the obtained separation membrane was tested, and the contact angle with water was found to be 117°. The membrane was then used for pervaporation separation of butanol. With a butanol concentration of 1.5 wt% on the feed side, a feed temperature of 60°C, and a permeation pressure of 100 Pa, the permeation flux of this mixed matrix membrane was measured to be 460 g / m³. -2 h -1 The separation factor is 19.

[0115] Comparative Example 1

[0116] Same as Example 1, except that polydimethylsiloxane methacrylate is replaced with an equal mass of hydroxyl-terminated polydimethylsiloxane.

[0117] (1) Preparation of casting solution: 2.0g of hydroxyl-terminated polydimethylsiloxane with a number average molecular weight of about 50,000, 0.2g of tetraethyl silicate, 0.02g of dibutyltin dilaurate, 0.5g of 2-methylimidazole and 18g of dichloromethane were mixed and stirred at 500rpm for 0.5h to obtain a uniformly dispersed casting solution.

[0118] (2) Coating: After vacuum degassing the casting solution for 5-15 minutes, coat it evenly on one side of a 50μm thick polyvinylidene fluoride (PVDF) / nonwoven base film.

[0119] (3) Curing: The liquid film was dried at 30°C for 5 hours and then heat-treated in an oven at 80°C for 12 hours to obtain an organic film with a thickness of 4.0 μm containing 2-methylimidazole (MOF organic ligand) on the surface of the substrate film.

[0120] (4) Crystallization: 1.0 g of zinc nitrate hexahydrate was dissolved in 40 g of deionized water. The material obtained in step (3) was immersed in the above zinc nitrate aqueous solution and treated at 35°C for 6 h. It was then rinsed three times with deionized water to obtain a mixed matrix film doped with 10.3 wt% ZIF-8 particles.

[0121] The contact angle of the obtained separation membrane was tested, and the contact angle with water was found to be 105°. The membrane was then subjected to pervaporation separation of butanol. With a butanol concentration of 1.5 wt% on the feed side, a feed temperature of 60°C, and a permeation pressure of 100 Pa, the permeation flux of this mixed matrix membrane was measured to be 280 g / m³. -2 h -1 The separation factor is 18.

[0122] Comparative Example 2

[0123] Same as Example 1, except that polydimethylsiloxane methacrylate is replaced with an equal mass of methyl methacrylate:

[0124] (1) Preparation of casting solution: 2.0g of methyl methacrylate, 0.5g of 2-methylimidazole, 0.05g of 2-hydroxy-2-methyl-1-phenylpropanone and 2.0g of dichloromethane were mixed and stirred at 500rpm for 0.5h to obtain a uniformly dispersed casting solution.

[0125] (2) Coating: After vacuum degassing the casting solution for 5-15 minutes, coat it evenly on one side of a 50μm thick polyvinylidene fluoride (PVDF) / nonwoven base film.

[0126] (3) Curing: The liquid film was dried at 30°C for 5 hours and then cured by UV irradiation for 10 minutes. An organic film with a thickness of 3.0 μm containing 2-methylimidazole (MOF organic ligand) on the surface was obtained on the base film, with a degree of polymerization m of 7.

[0127] (4) Crystallization: Dissolve 1.0 g of zinc nitrate hexahydrate in 40 g of deionized water, immerse the material obtained in step (3) in the above zinc nitrate aqueous solution, and treat it at a temperature of 35 °C for 6 h. Then rinse three times with deionized water to obtain a mixed matrix film doped with 8.6 wt% ZIF-8 particles.

[0128] The contact angle of the obtained separation membrane was tested, and the contact angle with water was found to be 96°. The membrane was then used for pervaporation separation of butanol. With a butanol concentration of 1.5 wt% on the feed side, a feed temperature of 60°C, and a permeation pressure of 100 Pa, the permeation flux of this mixed matrix membrane was measured to be 105 g m³ / s. -2 h -1 The separation factor is 15.

[0129] 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: (1) a polymer functional membrane; and (2) a base membrane for supporting the polymer functional membrane. The polymer in the polymer functional membrane comprises a polymer having a structure as shown in formula (a): In formula (a), R0 is an alkylene chain, R1 is a polysiloxane alkyl group, R2 is a hydrocarbon group or hydrogen, and m = 1-20.

2. The hybrid matrix membrane according to claim 1, wherein, R0 is a C1-10, preferably C3-6, alkylene chain; and / or R1 is a polysiloxane with a degree of polymerization of 10-500, preferably 100-300, and more preferably a polydimethylsiloxane, polymethyloctylsiloxane, or polymethylphenylsiloxane; and / or R2 is a C1-C3 hydrocarbon group or hydrogen; and / or The number average molecular weight of the monomers used to polymerize the polymer having the structure shown in formula (a) is 8,000-100,000 g / mol, preferably 20,000-100,000 g / mol; and / or m＝5-15。 3. The hybrid matrix membrane according to claim 1 or 2, wherein, The water contact angle of the hybrid matrix membrane is 110-127°, preferably 115-127°; and / or The hybrid matrix membrane exhibits a permeation flux of 950-2600 g m when separating a 5.0 wt% acetone aqueous solution at 40-80°C. -2 h -1 The preferred value is 1500-2600g m -2 h -1 The separation factor is 23-35, preferably 26-30; the permeation flux for separating 1.5wt% butanol aqueous solution at 40-60℃ is 350-780 g m -2 h -1 Preferably, it is 500-650g m -2 h -1 The separation factor is 18-25, preferably 20-22.

4. The hybrid matrix membrane according to any one of claims 1-3, wherein, The polymer functional membrane optionally contains at least one selected from polyalkyl acrylate, polytetrafluoroethylene, polyvinylidene fluoride, polyamide, polyimide, polyacrylonitrile, polyaniline, polypyrrole, and polyetheretherketone; preferably, The polymer having the structure shown in formula (a) accounts for at least 50% of the total mass of the polymer functional membrane, preferably 80-100%.

5. The hybrid matrix membrane according to any one of claims 1-4, wherein, The polymer functional membrane is filled with 1-70 wt% of the total polymer functional membrane, preferably 5-50 wt% of MOF; preferably, the organic ligand of the MOF is selected from imidazole ligands and / or terephthalic acid ligands, and the metal ion includes at least one of the transition metal ions. More preferably, The imidazole ligand is selected from at least one of 2-methylimidazolium, 2-formylimidazolium, benzimidazole, 2-nitroimidazolium, and 4-chloro-5-nitroimidazolium; and / or The terephthalic acid ligand is selected from at least one of terephthalic acid, 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, and 2-fluoroterephthalic acid; and / or The transition metal ions include at least one of Group IB, Group IIB, Group VIII, and Group IVB metal ions, and preferably include at least one of zinc, cobalt, iron, copper, and zirconium ions. More preferably, The MOF includes at least one of ZIF-8, ZIF-67, ZIF-7, ZIF-90, MOF-5, Cu(BDC), NH2-UiO-66, UiO-66, copper ion-doped UiO-66, copper ion-doped NH2-UiO-66, and MIL-53.

6. The hybrid matrix membrane according to any one of claims 1-5, wherein, The thickness of the base membrane in the hybrid matrix membrane is 10-3000 μm, preferably 50-200 μm; and / or, The thickness of the polymer functional membrane in the hybrid matrix membrane is 0.5-50 μm, preferably 2-20 μm.

7. The hybrid matrix membrane according to any one of claims 1-6, wherein, The base membrane is made of a porous material, preferably at least one of polyvinylidene fluoride, polyacrylonitrile, polytetrafluoroethylene, polyethersulfone, alumina, and silicon oxide. Preferably, the base membrane is a layered composite membrane consisting of a porous material layer and a supporting material layer.

8. The method for preparing the hybrid matrix membrane according to any one of claims 1-7, characterized in that, The preparation method includes the following steps: S1. Prepare a casting solution containing polymer monomers and photoinitiators; S2. The casting solution is coated on one side of the substrate film surface to form a liquid film, and a polymerization reaction is initiated to solidify the liquid film on the substrate film surface. Preferably, the preparation method includes the following steps: S1. Prepare a casting solution containing an organic ligand of MOF, a polymer monomer, and a photoinitiator; S2. The casting solution is coated on one side of the substrate membrane to form a liquid film, and a polymerization reaction is initiated to solidify the liquid film on the substrate membrane surface to obtain the precursor. S3. The precursor is reacted with the MOF metal ion source solution.

9. The preparation method according to claim 8, wherein, The conditions for the polymerization reaction include: a temperature of 25-60°C, preferably 30-45°C, more preferably 30-35°C; and / or a time of 3-60 min, preferably 10-30 min; and / or The conditions for the contact reaction include: a temperature of 25-150°C, preferably 35-80°C; and / or a time of 0.5-24h, preferably 3-12h, more preferably 5-10h.

10. The preparation method according to claim 8 or 9, wherein, The mass ratio of MOF organic ligand, polymeric monomer, photoinitiator, and first solvent in the casting solution is (0-1):(1-200):(0.01-1):(2:2000), preferably (0.5-1):(2-50):(0.02-0.5):(2-500); and / or The mass ratio of the metal salt to the second solvent in the MOF metal ion source solution is 1:(10-1000), preferably 1:(20-500); Preferably, the first solvent and the second solvent are each independently selected from at least one of methanol, ethanol, N,N-dimethylformamide, dichloromethane, chloroform, tetrahydrofuran, and n-heptane, and more preferably dichloromethane and / or n-heptane.

11. The application of the mixed matrix membrane according to any one of claims 1-7 in the pervaporation separation of organic solvents in aqueous solutions, preferably in the separation of organic solvents in aqueous solutions with a mass concentration not exceeding 45 wt%, more preferably the organic solvent is selected from at least one of alcohols, aldehydes, ketones, ethers and optionally esters and / or organic hydrocarbons.

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