A nanofluidic gel-mixed matrix membrane for olefin and alkane separation, its preparation method, and its application.

Abstract

This application discloses a nanofluidic gel-mixed matrix membrane for olefin / alkane separation, its preparation method, and its application, belonging to the field of membrane separation technology. The membrane is composed of a polymer matrix and a nanofluidic filler. The filler includes a crown core, a linker, and a crown layer. The crown core is a porous material with preferential adsorption for olefins, and the crown layer is a liquid organic material containing specific structures and functional groups. The crown layer is chemically bonded to the surface of the crown core to form the nanofluidic filler, which is then combined with the polymer matrix to prepare the gel-mixed matrix membrane. This application uses nanofluids as fillers, enabling membrane gelation, solving the problems of traditional filler aggregation and interfacial compatibility, and significantly improving the membrane's separation performance for olefins / alkanes, while also exhibiting high mechanical strength and stability. This membrane is particularly suitable for the efficient separation and purification of low-carbon olefins such as ethylene / ethane, propylene / propane, and propylene / N2.

Description

Technical Field

[0001] This application relates to a nanofluidic gel-mixed matrix membrane for the separation of olefins and alkanes, its preparation method, and its application, belonging to the field of membrane separation technology. Background Technology

[0002] Olefins (such as ethylene and propylene) are key raw materials in the petrochemical industry, and their purification process is crucial for downstream industries. Currently, cryogenic distillation is mainly used in industry to separate olefin / alkane mixtures, but problems such as high energy consumption for solvent regeneration and equipment corrosion still exist. In contrast, membrane separation technology has advantages such as low energy consumption, simple operation, and modular design, but the core challenge lies in developing membrane materials with both high selectivity and high permeability. Existing polymer membranes have insufficient capacity for separating olefins / alkanes, exhibiting low permeability and selectivity. Mixed matrix membranes can improve performance by introducing porous packing materials, but the poor interfacial compatibility between the packing material and the matrix, and the tendency of the packing material to agglomerate, lead to membrane defects and performance degradation. Furthermore, the strong interaction forces between polymers and packing materials in mixed matrix membranes can easily cause polymer chains to stiffen, reducing gas permeability. Summary of the Invention To address the shortcomings of traditional mixed matrix membranes in olefin and alkane separation technologies, which make it difficult to simultaneously achieve high mechanical strength, high stability, high selectivity, and high permeability, this application provides a nanofluidic gel mixed matrix membrane technology for olefin and alkane separation. This technology utilizes a crown-crown-layer structure of nanofluidic packing material, combining the preferential adsorption of the crown core with the functional group regulation of the crown layer to synergistically improve separation performance. Simultaneously, chemical bonds enhance the packing material-matrix interface and the stability of intramembrane components, thus overcoming the deficiencies of traditional mixed matrix membranes and preparing an olefin / alkane separation membrane with high gas separation performance, high mechanical strength, and high stability.

[0003] The technical solution adopted in this application is as follows: According to a first aspect of this application, a nanofluidic gel-mixed matrix membrane for olefin and alkane separation is provided, comprising: a polymer matrix and a nanofluidic filler; The nanofluid filler includes a crown core, a binder, and a coronal layer; The coronal nucleus and coronal layer are bonded together by a connecting agent via covalent or ionic bonds; The crown is a porous material modified with functional groups; The porous material is selected from at least one of metal-organic frameworks, covalent organic frameworks, and carbon-based porous materials; The connecting agent is selected from at least one of silane coupling agents, titanate coupling agents, and zirconate coupling agents; The coronal layer is a liquid organic material modified with functional groups; The liquid organic compound is selected from at least one of polyacetylene group, aromatic ring, aromatic ether, and polyether; The functional groups in the coronal nucleus and coronal layer are independently selected from at least one of hydroxyl, amino, carboxyl, sulfonic acid, ester, cyano, and epoxy groups.

[0004] Optionally, the content of the nanofluid filler in the nanofluid gel hybrid matrix membrane is 10~85wt%.

[0005] Optionally, the polymer matrix is ​​selected from at least one rubbery polymer selected from polydimethylsiloxane, polyoctylmethylsiloxane, fluorosilicone rubber, poly(ether-b-amide), polyurethane, and polyether-ester.

[0006] Optionally, the pore size of the crown is 0.39~20 nm.

[0007] Optionally, the molecular weight of the organic matter in the coronal layer is 100~10000 Da.

[0008] According to a second aspect of this application, a method for preparing the aforementioned nanofluidic gel-mixed matrix membrane for olefin and alkane separation is provided, characterized in that it comprises: Preparation of nanofluid fillers; The film-forming solution containing the nanofluid filler, polymer matrix, and solvent is used to form a film and then dried to obtain the nanofluid gel mixed matrix membrane for olefin and alkane separation.

[0009] Optionally, the preparation method of the nanofluid filler includes the following steps: A solution containing coronal core material and connecting agent material is subjected to reaction I under stirring conditions. After reaction I is completed, coronal layer material is added to the solution and reaction II is carried out under stirring conditions to obtain a reaction solution; or, a solution containing coronal core material, connecting agent material and coronal layer material is subjected to reaction III under stirring conditions to obtain a reaction solution. The reaction solution was dialyzed and dried to obtain the nanofluid filler.

[0010] Optionally, the mass ratio of the coronal nucleus to the coronal layer material is 1:0.05~30.

[0011] Optionally, the conditions for reaction I include: stirring the reaction at a temperature of 40~95℃ for 5~48 h.

[0012] Optionally, the conditions for reaction II include: stirring the reaction at a temperature of 40~95°C for 5~48 h.

[0013] Optionally, the conditions for reaction III include: stirring the reaction at a temperature of 40~95°C for 5~96 h.

[0014] Optionally, the dialysis conditions include 24 to 96 hours.

[0015] Optionally, the total mass concentration of the polymer matrix and nanofluid filler in the film-forming solution is 1~50 wt%.

[0016] Optionally, the preparation steps of the film-forming solution containing the nanofluid filler, polymer matrix, and solvent include: The polymer matrix, nanofluid filler, and solvent are mixed; or, the polymer matrix and solvent I are mixed to obtain mixed solution I, and the nanofluid filler and solvent II are mixed to obtain mixed solution II, and then mixed solution I and mixed solution II are mixed again.

[0017] According to a third aspect of this application, at least one of the aforementioned nanofluidic gel mixed matrix membrane for olefin / alkane separation or the nanofluidic gel mixed matrix membrane for olefin / alkane separation prepared according to the aforementioned preparation method is provided for use in olefin / alkane separation.

[0018] Optionally, the olefin / alkane is selected from a combination of ethylene / ethane, propylene / propane, butene / butane, and propylene / N2.

[0019] The beneficial effects of this application include: (1) Improved performance in olefin / alkane separation: The gel network structure formed by the liquid organic canopy layer of the nanofluidic packing and the polymer matrix not only increases the free volume of the membrane but also provides more diffusion channels for gas molecules. Simultaneously, specific functional groups and structures in the canopy layer exhibit selective adsorption and transport-promoting effects on olefins, resulting in excellent comprehensive performance of the nanofluidic gel-mixed matrix membrane in olefin / alkane separation. Compared to traditional polymer membranes or ordinary mixed matrix membranes, it can simultaneously improve permeate flux and selectivity. Taking ethylene / ethane separation as an example, the membrane material of this application can improve ethylene permeability by 10-150% while maintaining high ethylene / ethane selectivity.

[0020] (2) Excellent interfacial compatibility and filler dispersibility: The “crown core-connector-crown layer” structural design enables the filler to form an ideal interface with the polymer matrix, effectively eliminating interfacial defects; the liquid organic structure of the crown layer effectively reduces the surface energy and agglomeration tendency of nanoparticles, so that the filler can still maintain uniform dispersion under high load conditions, avoiding the generation of defect voids.

[0021] (3) Improved mechanical properties and stability: The chemical bonding formed by the binder ensures that the coronal layer is firmly anchored to the surface of the coronal nucleus, which improves the thermal stability and mechanical properties of the nanofluid filler and effectively extends the service life of the membrane. Attached Figure Description

[0022] Figure 1 This is a cross-sectional electron microscope image of the EM400 / UIO-66-OH mixed matrix membrane of Comparative Example 2 of this application; Figure 2 This is a cross-sectional electron microscope image of the EM400 / UIO-66-OH@KH560-M2070 nanofluidic gel hybrid matrix of Example 1 of this application; Figure 3 This is a comparison of the membrane mechanical properties of Comparative Example 3 and Example 1 of this application; Figure 4 The diagram shows the thermal decomposition of Examples 1-4 of this application with polyetheramine M2070. Detailed Implementation

[0023] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0024] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0025] Unless otherwise specified, all test methods are standard and all instrument settings are those recommended by the manufacturer.

[0026] According to one embodiment of this application, and according to a first aspect of this application, a nanofluidic gel-mixed matrix membrane for olefin and alkane separation is provided, comprising: a polymer matrix and a nanofluidic filler. The nanofluid filler includes a crown core, a binder, and a coronal layer; The core and the coronal layer are bonded together by a linker via covalent or ionic bonds. This bonding between the core and the coronal layer effectively prevents nanoparticle aggregation and enhances their dispersibility in the polymer matrix, while also improving the thermal stability of the coronal layer material in the membrane. The crown is a porous material modified with functional groups; The porous material is selected from at least one of metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and carbon-based porous materials. For example, the porous material is one of UIO-66-OH, MIL-53-OH, and nanoporous molecular sieves (CMS). The crown core is selected from porous materials that preferentially adsorb olefins, which facilitates gas dissolution in the membrane, and the pores provide diffusion channels for the gas. The functional groups on the surface of the porous material enhance the chemical bonding ability with the linker, providing active sites for subsequent surface modification. Furthermore, they regulate the polarity and hydrophobicity of the crown core surface, enhancing the interaction between the crown core and the polymer matrix, improving interfacial compatibility, and reducing filler agglomeration.

[0027] The linker is selected from at least one of silane coupling agents, titanate coupling agents, and zirconate coupling agents; the linker's function is to bridge the porous crown core and the organic crown layer, forming a stable nanofluid structure. Silane, titanate, and zirconate coupling agents can form chemical bonds with porous surfaces and organic molecules, respectively, thereby firmly binding the two together. The canopy layer is a liquid organic material modified with functional groups. For example, the liquid organic material modified with functional groups is one of polyetheramine JEFFAMINE® M2070 and JEFFAMINE® ED2000. The liquid organic canopy layer can act as a gelling agent to gel the membrane, increase the free volume of the membrane, and facilitate gas permeation. The liquid organic material is selected from at least one of polyacetylene group, aromatic ring, aromatic ether, and polyether; the selected material has strong adsorption to olefins and preferential dissolution characteristics for olefins. The coronal layer has polyacetylene group, aromatic ring, aromatic ether, and polyether structure, which has high interaction force with olefins and is conducive to promoting the permeability of olefins. The functional groups in the coronal nucleus and coronal lamina are independently selected from at least one of hydroxyl (-OH), amino (-NH2), carboxyl (-COOH), sulfonic acid (-SO3H), ester, cyano, and epoxy groups.

[0028] This application designs a nanofluidic gel hybrid matrix structure, synergistically utilizing the size sieving / adsorption effect of porous packing and the preferential dissolution ability of liquid coronal layer, while solving the problems of poor packing dispersion and weak interfacial compatibility, to achieve efficient separation of olefins / alkanes.

[0029] In one embodiment, the content of the nanofluidic filler in the nanofluidic gel hybrid matrix membrane is 10~85 wt%. When the content of the nanofluidic filler is too low, its effect on improving the gas separation performance of the nanofluidic gel hybrid matrix membrane is small, and the preferential adsorption and diffusion advantages of the filler cannot be fully utilized; when the content of the nanofluidic filler is too high, it leads to the membrane becoming brittle, reducing the mechanical properties of the membrane, making processing difficult, and increasing costs.

[0030] In one embodiment, the nanofluid filler is dispersed and filled in the nanofluid gel hybrid matrix membrane.

[0031] In one embodiment, the polymer matrix is ​​selected from at least one rubbery polymer chosen from polydimethylsiloxane (PDMS), polyoctylmethylsiloxane, fluorosilicone rubber, poly(ether-β-amide), polyurethane (PU), and polyether-ester. Exemplarily, the polymer matrix is ​​one of Pebax 1657, Pebax 2533, EM400, and PDMS. These polymer matrices possess high elasticity and low glass transition temperature, effectively improving gas permeability.

[0032] In one embodiment, the metal in the metal-organic framework material is selected from one of Zn, Cu, Fe, Co, Ag, Cr, and Zr. MOFs have a regular and tunable pore structure and a large specific surface area, which can achieve size sieving and selective adsorption of olefins / alkanes. MOFs containing open metal sites (such as Cu-BTC) can undergo weak coordination with olefins, preferentially adsorbing olefins, thereby improving separation selectivity.

[0033] In one embodiment, the covalent organic framework contains at least one of a cyano (-CN), a pyridyl, a benzene ring, or a triazine unit. COFs possess high specific surface area and tunable pore size, and exhibit good chemical stability. These highly polar or electron-rich groups can interact with olefin double bonds, enhancing olefin affinity.

[0034] In one embodiment, the carbon-based porous material is activated carbon and / or carbon molecular sieve (CMS). Carbon materials have high chemical stability and are widely available, and can be used to sieve olefins / alkanes by controlling the pore structure.

[0035] In one embodiment, the pore size of the crown is 0.39~20 nm. The minimum kinetic diameter of C2H4 in alkenes and alkanes is 0.39 nm, and grafting the porous material with the crown layer reduces the pore size of the porous material. Therefore, in order to provide effective diffusion space for gas molecules, the pore size of the porous material must be at least greater than 0.39 nm; however, if the pore size is too large, the crown layer material can easily enter the pores, causing pore blockage.

[0036] In one embodiment, the molecular weight of the organic matter in the coronal layer is 100 to 10,000 Da.

[0037] According to a second aspect of this application, a method for preparing the aforementioned nanofluidic gel-mixed matrix membrane for olefin and alkane separation is provided, characterized in that it comprises: Preparation of nanofluid fillers; The film-forming solution containing the nanofluid filler, polymer matrix, and solvent is used to form a film and then dried to obtain the nanofluid gel mixed matrix membrane for olefin and alkane separation.

[0038] In one embodiment, the method for preparing the nanofluid filler includes the following steps: A solution containing coronal core material and connecting agent material is subjected to reaction I under stirring conditions. After reaction I is completed, coronal layer material is added to the solution and reaction II is carried out under stirring conditions to obtain a reaction solution; or, a solution containing coronal core material, connecting agent material and coronal layer material is subjected to reaction III under stirring conditions to obtain a reaction solution. The reaction solution was dialyzed and dried to obtain the nanofluid filler.

[0039] In one embodiment, the mass ratio of the crown core to the coronal layer material is 1:0.05~30. When the mass ratio of the crown core to the coronal layer material is too high, the coronal layer material cannot be fully grafted onto the crown core. A mass ratio that is too low and a coronal layer molecular weight that is too low may result in incomplete coverage or an excessively thin coronal layer, making it difficult to effectively shield the surface energy of the crown core or improve compatibility with the matrix. An excessively high coronal layer molecular weight may weaken the coronal layer chain movement, reduce the membrane's free volume fraction, and thus decrease membrane permeability.

[0040] In one embodiment, the conditions for reaction I include: stirring the reaction at a temperature of 40~95°C for 5~48 h.

[0041] In one embodiment, the conditions for reaction II include: stirring the reaction at a temperature of 40~95°C for 5~48 hours.

[0042] In one embodiment, the conditions for reaction III include: stirring the reaction at a temperature of 40-95°C for 5-96 hours.

[0043] In one embodiment, the dialysis conditions include 24 to 96 hours.

[0044] In one embodiment, the total mass concentration of the polymer matrix and nanofluid filler in the film-forming solution is 1 to 50 wt%.

[0045] In one embodiment, the preparation step of the film-forming solution containing the nanofluid filler, polymer matrix, and solvent includes: The polymer matrix, nanofluid filler, and solvent are mixed; or, the polymer matrix and solvent I are mixed to obtain mixed solution I, and the nanofluid filler and solvent II are mixed to obtain mixed solution II, and then mixed solution I and mixed solution II are mixed again.

[0046] In one embodiment, the preparation method of the nanofluid filler is as follows: Step 1: This includes methods A and B. Method A includes the following steps: adding the crown nucleus and connecting agent to a solvent and stirring the mixture at 40–95°C for 5–48 h; after the reaction is complete, adding the coronal layer and stirring the mixture at 40–95°C for 5–48 h to generate a reaction solution. Method B includes the following steps: adding the crown nucleus, connecting agent, and coronal layer to a solvent to prepare a reaction solution and stirring the mixture at 40–95°C for 5–96 h. Step 2: Placing the reaction solution from Step 1 into a dialysis bag and dialyzing it in water for 24–96 h. Step 3: Drying the sample to obtain the nanofluidic filler.

[0047] In one embodiment, the method for preparing the nanofluidic gel hybrid matrix film is as follows: Step 1: Mix the aforementioned polymer matrix and nanofluid filler with a solvent to obtain the film-forming solution; or mix the polymer matrix with solvent I, mix the nanofluid filler with solvent II, and finally mix mixed solution I with mixed solution II to obtain the film-forming solution.

[0048] Step 2: The film-forming liquid obtained in Step 1 is used to form a film by a blade coating method or a casting method, and then dried to obtain the nanofluid gel mixed matrix film.

[0049] According to a third aspect of this application, at least one of the aforementioned nanofluidic gel mixed matrix membrane for olefin / alkane separation or the nanofluidic gel mixed matrix membrane for olefin / alkane separation prepared according to the aforementioned preparation method is provided for use in olefin / alkane separation.

[0050] In one embodiment, the olefin / alkane is selected from a combination of ethylene / ethane, propylene / propane, butene / butane, and propylene / N2.

[0051] Example 1 1 g of ball-milled UIO-66-OH was dispersed in 19 ml of water. A certain amount of γ-(2,3-epoxypropoxy)-propyltrimethoxysilane (KH560) was dissolved in methanol to prepare a 5 wt% solution, which was then added to the UIO-66-OH dispersion, and the reaction was carried out at 50 °C for 24 hours. Subsequently, 10 g of polyetheramine JEFFAMINE® M2070 was dissolved in methanol to prepare a 10 wt% M2070 solution, which was then added to the above reaction solution, and the reaction was continued at 50 °C for 24 hours (the amount of KH560 was equivalent to the molar amount of M2070). After the reaction was completed, the resulting reaction solution was dialyzed in an MWCO5000 dialysis bag for 24 hours. After the dialysate was dehydrated by vacuum rotary evaporation, the sample in the rotary evaporation flask was rinsed with methanol. Finally, a large amount of methanol solvent was removed by preliminarily removing it in an oven, and then it was dried in a vacuum oven at 80°C to obtain UIO-66-OH@KH560-M2070 nanofluid filler with a mass ratio of UIO-66-OH to M2070 of 1:10.

[0052] 0.3 g of the aforementioned UIO-66-OH@KH560-M2070 nanofluidic filler was dispersed in 18.5 g of dichloromethane and sonicated for 4 hours. 1.2 g of the polyether ester block polymer matrix EM400 was dissolved in 30 g of dichloromethane and continuously heated and stirred at 50°C for 5 hours. The nanofluidic filler dispersion was poured into the polymer matrix solution, stirred at room temperature for 2 hours, and then poured onto a polytetrafluoroethylene petri dish. A large amount of solvent was evaporated at room temperature. After film formation, the membrane was placed in a 40°C vacuum oven for 4 days to completely remove residual solvent, finally obtaining an EM400 / UIO-66-OH@KH560-M2070 nanofluidic gel hybrid matrix membrane with a nanofluidic filler content of 20 wt%.

[0053] Examples 2-4 The preparation method is the same as in Example 1, except that different ratios of EM400 to nanofluid filler are used to weigh EM400 and filler to prepare gel-mixed matrix membranes with different contents of UIO-66-OH@KH560-M2070 nanofluid filler. The specific amounts of EM400 and nanofluid filler used are shown in Table 1. Table 1

[0054] Example 5 1 g of ball-milled MIL-53-OH was dispersed in 19 ml of water. A 5 wt% solution of 3-(trihydroxysilyl)-propanesulfonic acid (SIT) was prepared by dissolving a certain amount of SIT in methanol and added to the MIL-53-OH dispersion. The reaction was carried out at 70°C for 24 hours. Subsequently, 15 g of polyether diamine JEFFAMINE® ED2000 was dissolved in methanol to prepare a 10 wt% ED2000 solution and added to the above reaction solution. The reaction was continued at 50°C for 24 hours (the amount of SIT was equivalent to the molar amount of ED2000). After the reaction was completed, the resulting reaction solution was dialyzed in a MWCO5000 dialysis bag for 72 hours. After the dialysate was dehydrated by vacuum rotary evaporation, the sample in the rotary evaporation flask was rinsed with methanol. Finally, a large amount of methanol solvent was removed by preliminarily removing it in an oven, and then it was dried in a vacuum oven at 80°C to obtain MIL-53-OH@SIT-ED2000 nanofluid filler with a mass ratio of MIL-53-OH to ED2000 of 1:15.

[0055] 0.3 g of the above-mentioned MIL-53-OH@SIT-ED2000 nanofluidic filler was dispersed in 18.5 g of anhydrous ethanol and sonicated for 4 hours. 1.2 g of the poly(ether-b-amide) block polymer matrix Peabx2533 was dissolved in 30 g of anhydrous ethanol and heated and stirred at 80°C for 5 hours. The nanofluidic filler dispersion was poured into the polymer matrix solution, stirred at room temperature for 2 hours, and then poured onto a polytetrafluoroethylene petri dish. A large amount of solvent was evaporated at room temperature. After film formation, the film was placed in a vacuum oven at 40°C for 4 days to completely remove residual solvent, finally obtaining a Peabx2533 / MIL-53-OH@SIT-ED2000 nanofluidic gel hybrid matrix film with a nanofluidic filler content of 20 wt%.

[0056] Examples 6-8 According to the specific implementation method of Example 5, different ratios of Pebax2533 to nanofluid filler were used to prepare gel-mixed matrix membranes with different contents of MIL-53-OH@SIT-ED2000 nanofluid filler. The specific amounts of Pebax2533 and nanofluid filler used are shown in Table 2. Table 2

[0057] Examples 9-12 According to the specific implementation method of Example 1, COF-HNU13-NH2@KH560-PEG600 nanofluids were prepared using different ratios of COF-HNU13-NH2 and polyethylene glycol PEG600. The prepared COF-HNU13-NH2@KH560-PEG600 nanofluids were then added to silicone rubber PDMS using n-hexane as the solvent to prepare a 20 wt% PDMS / COF-HNU13-NH2@KH560-PEG600 nanofluid gel hybrid matrix film. The specific amounts of PDMS, COF-HNU13-NH2, and PEG600 are shown in Table 3. Table 3

[0058] Example 13 1 g of ball-milled hydroxyl-modified nanoporous molecular sieve (CMS-OH) was dispersed in 19 ml of water. A certain amount of phthalate coupling agent (TCA-44) was dissolved in methanol to prepare a 5 wt% solution, which was added to the CMS-OH dispersion. 10 g of polyethylene glycol (PEG800) was dissolved in methanol to prepare a 10 wt% M2070 solution, which was added to the above reaction solution. The reaction was carried out at 60 °C for 48 hours. After the reaction was completed, the resulting reaction solution was dialyzed in a MWCO5000 dialysis bag for 24 hours. After the dialysate was dehydrated by vacuum rotary evaporation, the sample in the rotary evaporation flask was rinsed with methanol. Finally, the sample was dried in an oven to remove a large amount of methanol solvent, and then dried in a vacuum oven at 80 °C to obtain CMS-OH@TCA-44-PEG800 nanofluidic filler with a CMS-OH to PEG800 mass ratio of 1:10.

[0059] 0.3 g of the CMS-OH@TCA-44-PEG800 nanofluidic filler was dispersed in 18.5 g of ethanol / water (7 / 3) and sonicated for 4 hours. 1.2 g of Pebax 1657 was dissolved in 30 g of ethanol / water (7 / 3) and heated and stirred at 80°C for 5 hours. The nanofluidic filler dispersion was poured into the polymer matrix solution and stirred at room temperature for 2 hours. The mixture was then poured onto a polytetrafluoroethylene (PTFE) petri dish, and the solvent was evaporated at room temperature to remove a large amount of solvent. After film formation, the film was placed in a 40°C vacuum oven for 4 days to completely remove residual solvent, finally obtaining a Pebax 1657 / CMS-OH@TCA-44-PEG800 nanofluidic gel hybrid matrix film with a nanofluidic filler content of 20 wt%.

[0060] Examples 14-16 The preparation method is the same as in Example 1, except that different Pebax 1657 and nanofluid filler ratios are used to weigh out Pebax 1657 and filler to prepare gel-mixed matrix membranes with different CMS-OH@TCA-44-PEG800 nanofluid filler contents. The specific amounts of Pebax 1657 and nanofluid filler used are shown in Table 4. Table 4

[0061] Comparative Example 1 1.5 g of polyether ester block polymer matrix EM400 was dissolved in 48.5 g of dichloromethane and heated and stirred at 50 °C for 5 hours. After stirring at room temperature for 2 hours, the solution was poured onto a polytetrafluoroethylene petri dish, and a large amount of solvent was evaporated at room temperature. After film formation, the film was placed in a 40 °C vacuum oven for 4 days to completely remove residual solvent, finally obtaining the EM400 polymer film.

[0062] Comparative Example 2 0.027 g of UIO-66-OH filler was dispersed in 18.5 g of dichloromethane and sonicated for 4 hours. 1.473 g of polyether ester block polymer matrix EM400 was dissolved in 30 g of dichloromethane and continuously heated and stirred at 50 °C for 5 hours. The filler dispersion was poured into the polymer matrix solution, stirred at room temperature for 2 hours, and then poured onto a polytetrafluoroethylene petri dish. A large amount of solvent was evaporated at room temperature. After film formation, the membrane was placed in a 40 °C vacuum oven for 4 days to completely remove residual solvent, finally obtaining an EM400 / UIO-66-OH gel hybrid matrix membrane with a UIO-66-OH filler content of 1.82 wt%.

[0063] Comparative Example 3 0.3 g of UIO-66-OH / M2070 filler (UIO-66-OH and M2070 mass ratio of 1:10) was dispersed in 18.5 g of dichloromethane and sonicated for 4 hours. 1.2 g of polyether ester block polymer matrix EM400 was dissolved in 30 g of dichloromethane and heated and stirred at 50 °C for 5 hours. The filler dispersion was poured into the polymer matrix solution, stirred at room temperature for 2 hours, and then poured onto a polytetrafluoroethylene (PTFE) petri dish. A large amount of solvent was evaporated at room temperature to remove the solvent. After film formation, the membrane was placed in a 40 °C vacuum oven for 4 days to completely remove residual solvent, finally obtaining an EM400 / UIO-66-OH / M2070 gel-mixed matrix membrane with a filler / gelant content of 20 wt%.

[0064] Comparative Example 4 1.5 g of the poly(ether-b-amide) block polymer matrix Pebax2533 was dissolved in 48.5 g of anhydrous ethanol and heated and stirred at 80 °C for 5 hours. After stirring at room temperature for 2 hours, the solution was poured onto a polytetrafluoroethylene petri dish, and a large amount of solvent was evaporated at room temperature. After film formation, the film was placed in a 40 °C vacuum oven for 4 days to completely remove any residual solvent, finally obtaining the Pebax2533 polymer film.

[0065] Comparative Example 5 1.5 g of PDMS was dissolved in 48.5 g of n-hexane and heated and stirred at 80 °C for 5 hours. After stirring at room temperature for 2 hours, the solution was poured onto a polytetrafluoroethylene (PTFE) petri dish, and the solvent was evaporated at room temperature to remove a large amount of solvent. After film formation, the film was placed in a 40 °C vacuum oven for 4 days to completely remove any residual solvent, finally obtaining the PDMS polymer film.

[0066] Comparative Example 6 1.5 g of the Pebax 1657 polymer matrix was dissolved in 48.5 g of ethanol / water (7 / 3), and heated and stirred continuously at 80 °C for 5 hours. Then, after stirring at room temperature for 2 hours, the solution was poured onto a polytetrafluoroethylene (PTFE) petri dish, and a large amount of solvent was evaporated at room temperature. After film formation, the film was placed in a 40 °C vacuum oven for 4 days to completely remove any residual solvent, finally obtaining the Pebax 1657 polymer film.

[0067] Test case The membranes prepared in Examples 1-12 and Comparative Examples 1-5 were tested for olefin and alkane permeability. Their ethylene and propylene permeability coefficients and ethylene / ethane, propylene / propane, and propylene / N2 selectivity are shown in Table 4. The CO2 permeability coefficients and CO2 / N2 separation selectivity of Examples 1-4 and Comparative Example 1 are shown in Table 5.

[0068] Example 1 is a gel-mixed matrix membrane using 20 wt% UIO-66-OH@KH560-M2070 nanofluid as filler. Its ethylene permeation coefficient is 81.14 Barrer, and the ethylene / ethane selectivity is 1.57; the propylene permeation coefficient is 198.63 Barrer, the propylene / propane selectivity is 2.39, and the propylene / N2 selectivity is 11.54. The olefin / alkane separation performance of the nanofluid gel-mixed matrix membrane in Example 1 is significantly improved compared to the pure EM400 polymer membrane in Comparative Example 1 and the EM400 / UIO-66-OH mixed matrix membrane in Comparative Example 2. Furthermore, Example 1 exhibits a CO2 permeation coefficient of 410.6 Barrer and a CO2 / N2 selectivity of 30.4, demonstrating good CO2 / N2 separation selectivity.

[0069] Figure 1 The image shows a cross-sectional electron microscope (EM) image of the EM400 / UIO-66-OH mixed matrix membrane of Comparative Example 2. As can be seen from the image, the UIO-66-OH filler significantly aggregates within the membrane, resulting in irregular voids. This leads to non-selective gas permeation, which is detrimental to improving gas selectivity.

[0070] Figure 2 This is a cross-sectional electron microscope image of the EM400 / UIO-66-OH@KH560-M2070 nanofluidic gel hybrid matrix membrane of Example 1. In the nanofluidic gel hybrid matrix membrane, the UIO-66-OH particles are uniformly dispersed, and the interfacial compatibility between the particles and the polymer is good, indicating that the nanofluid, as a filler, can promote the dispersion of the crown particles.

[0071] Comparative Example 3 is an EM400 / UIO-66-OH / M2070 membrane with the same composition as that in Example 1. The olefin / alkane separation performance of the membrane in Comparative Example 3 is not significantly improved compared to the nanofluidic gel mixed matrix membrane in Example 1.

[0072] Figure 3 For the comparison of the mechanical properties of the membranes in Comparative Example 3 and Example 1, the tensile strength, Young's modulus, and elongation at break of the nanofluid gel hybrid matrix membrane prepared in Example 1 are slightly higher than those of the membrane in Comparative Example 3. This is mainly because the coronal layer and the coronal core of the nanofluid gel hybrid matrix membrane in Example 1 are linked by covalent bonds, and a strong hydrogen bond network is formed between the nanofluid and the polymer, which increases the mechanical properties of the membrane.

[0073] Examples 1-4 show EM400 / MUIO-66-OH@KH560-M2070 gel-mixed matrix membranes with different nanofluid contents. The permeation coefficients of ethylene and propylene in the membranes increased with increasing nanofluid content, and the separation selectivity for ethylene / ethane and propylene / propane also slightly improved. Examples 5-6 show Pebax2533 / MIL-53-OH@SIT-ED20000 gel-mixed matrix membranes with different nanofluid contents. Similarly, the gas separation performance of these membranes increased with increasing nanofluid content. The improved gas separation performance of the nanofluid gel-mixed matrix membranes is mainly due to the following factors: firstly, the porous crowns provide diffusion channels for gas in the membrane, promoting gas permeation; secondly, the crown layer material promotes crown dispersion, avoiding the generation of irregular voids, which is beneficial for improving separation selectivity. Simultaneously, the crown layer material itself increases the membrane's free volume and has strong adsorption for olefins, contributing to improved olefin and alkane separation.

[0074] Figure 4 The figures show the thermal decomposition diagrams of Examples 1-4 with polyetheramine M2070. The figures indicate that the decomposition temperature of the nanofluidic gel mixed matrix film is significantly higher than that of pure M2070. This enhanced thermal stability is attributed to the KH560 covalent bond between M2070 and the crown core MIL-101-OH, and the formation of a strong hydrogen bond network with Pebax 30R51, which increases the stability of M2070 in the film.

[0075] Table 5

[0076] Table 6

[0077] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A nanofluidic gel-mixed matrix membrane for olefin and alkane separation, characterized in that, include: Polymer matrix and nanofluid filler; The nanofluid filler includes a crown core, a binder, and a coronal layer; The coronal nucleus and coronal layer are bonded together by a connecting agent via covalent or ionic bonds; The crown is a porous material modified with functional groups; The porous material is selected from at least one of metal-organic frameworks, covalent organic frameworks, and carbon-based porous materials; The connecting agent is selected from at least one of silane coupling agents, titanate coupling agents, and zirconate coupling agents; The coronal layer is a liquid organic material modified with functional groups; The liquid organic compound is selected from at least one of polyacetylene group, aromatic ring, aromatic ether, and polyether; The functional groups in the coronal nucleus and coronal layer are independently selected from at least one of hydroxyl, amino, carboxyl, sulfonic acid, ester, cyano, and epoxy groups.

2. The preparation method according to claim 1, characterized in that, In the nanofluid gel hybrid matrix membrane, the content of the nanofluid filler is 10~85 wt%.

3. The preparation method according to claim 1, characterized in that, The polymer matrix is ​​selected from at least one rubbery polymer selected from polydimethylsiloxane, polyoctylmethylsiloxane, fluorosilicone rubber, poly(ether-b-amide), polyurethane, and polyether-ester.

4. The preparation method according to claim 1, characterized in that, The pore size of the crown nucleus is 0.39~20 nm; Preferably, the molecular weight of the organic matter in the coronal layer is 100~10000 Da.

5. The method for preparing the nanofluidic gel-mixed matrix membrane for olefin and alkane separation according to any one of claims 1 to 4, characterized in that, include: Preparation of nanofluid fillers; The film-forming solution containing the nanofluid filler, polymer matrix, and solvent is used to form a film and then dried to obtain the nanofluid gel mixed matrix membrane for olefin and alkane separation.

6. The preparation method according to claim 5, characterized in that, The preparation method of the nanofluid filler includes the following steps: A solution containing coronal material and connecting agent material is subjected to reaction I under stirring conditions. After reaction I is completed, coronal material is added to the solution and reaction II is carried out under stirring conditions to obtain a reaction solution. Alternatively, a solution containing core material, binder material, and coronal material can be reacted under stirring conditions to obtain a reaction solution. The reaction solution was dialyzed and dried to obtain the nanofluid filler.

7. The preparation method according to claim 6, characterized in that, The mass ratio of the coronal core to the coronal layer material is 1:0.05~30; Preferably, the conditions for reaction I include: stirring the reaction at a temperature of 40~95℃ for 5~48 h; Preferably, the conditions for reaction II include: stirring the reaction at 40~95℃ for 5~48 h; Preferably, the conditions for reaction III include: stirring the reaction at 40~95°C for 5~96 h; Preferably, the dialysis conditions include 24 to 96 hours.

8. The preparation method according to claim 5, characterized in that, The total mass concentration of the polymer matrix and nanofluid filler in the film-forming solution is 1~50 wt%. Preferably, the preparation steps of the film-forming solution containing the nanofluid filler, polymer matrix, and solvent include: The polymer matrix, nanofluid filler, and solvent are mixed; or, the polymer matrix and solvent I are mixed to obtain mixed solution I, and the nanofluid filler and solvent II are mixed to obtain mixed solution II, and then mixed solution I and mixed solution II are mixed again.

9. The application of at least one of the nanofluidic gel mixed matrix membranes for olefin / alkane separation according to any one of claims 1 to 4 or the nanofluidic gel mixed matrix membranes for olefin / alkane separation obtained by the preparation method according to any one of claims 5 to 8 in olefin / alkane separation.

10. The application according to claim 9, characterized in that, The olefin / alkane is selected from a combination of ethylene / ethane, propylene / propane, butene / butane, and propylene / N2.

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