Gas separation mixed matrix membrane and preparation method thereof

Abstract

The invention discloses a gas separation mixed matrix membrane and a preparation method thereof, and belongs to the technical field of gas membrane separation. The mixed matrix membrane comprises a high polymer material matrix and a porous material, and through hydrogen-bond interaction formed by the high polymer material matrix and the porous material, the interfacial compatibility between a filler and the polymer matrix and the dispersity of the filler are remarkably enhanced; the pore material is used as a pore structure regulator, improves the chain accumulation mode of a polymer matrix and provides a selective gas separation window, and the gas screening capacity of the membrane is remarkably improved through the synergistic effect of the pore material and the pore structure regulator. The mixed matrix membrane is prepared by adopting a solution pouring method, the process is simple, the repeatability is high, large-area preparation is easy, the cost is low, the method is suitable for the fields of helium separation, hydrogen purification, natural gas purification, biogas purification and carbon capture, and the application prospect is wide.

Description

Technical Field

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

[0002] Chemical separation, including distillation, evaporation, and drying in industrial processes, as well as other heat-driven industrial separation processes, accounts for 10%–15% of global energy consumption and is one of the important directions for achieving carbon emission reduction in the industrial sector. Compared with energy-intensive heat-driven separation technologies, membrane separation technology can improve energy efficiency by an order of magnitude, theoretically achieving energy savings of up to 90%. Due to its advantages in energy efficiency, simplicity, scalability in manufacturing, and small footprint, membrane technology has been given priority in the purification of many key gases and has become an effective alternative to traditional gas separation and purification technologies (such as cryogenic distillation and high-pressure adsorption), playing an important role in helium recovery, hydrogen purification, carbon capture, and natural gas purification.

[0003] Easy-to-process, low-cost polymer membranes have become key materials for achieving high yields and high purity of gas products in practical industrial applications. However, the gas transport performance of traditional polymer membranes is constrained by the inherent trade-off between permeability and selectivity, resulting in most existing traditional polymer membranes exhibiting low permeability and moderate selectivity, making it difficult to meet the stringent requirements of high-end industrial scenarios, such as: Helium extraction scenario: The helium content in natural gas is usually less than 0.5%. To achieve economical helium recovery, the He / CH4 selectivity of the gas separation membrane must be greater than 1000, which is a critical threshold for industrial applications. Hydrogen purification scenario: 85% of the world's hydrogen energy is produced by the cracking of methane gas. When purifying hydrogen industrially, the H2 / CH4 separation selectivity must be at least greater than 50. Natural gas upgrading scenario: The small amount of CO2 present in natural gas can corrode gas transportation pipelines and reduce the calorific value of natural gas. CO2 needs to be removed by membrane separation, which puts forward requirements on the CO2 / CH4 selectivity and long-term stability of the membrane. However, the performance of existing pure polymer membranes generally cannot meet the above-mentioned industrial requirements, which to some extent restricts the development of gas separation membranes.

[0004] Membranes based on molecular sieve materials can achieve high gas selectivity due to their ability to distinguish gases based on molecular size and shape. However, these materials often suffer from poor mechanical properties and high brittleness, making it difficult to directly process them into large-area self-supporting membranes, thus limiting their large-scale application. Hybrid matrix membranes, by incorporating molecular sieve materials with specific pore sizes as fillers into a processable polymer matrix, effectively combine the advantages of high filler selectivity and easy polymer processability, thereby improving gas separation efficiency. However, the development of existing hybrid matrix membranes still faces challenges: Poor interfacial compatibility: Significant differences in the physicochemical properties (such as surface energy, polarity, and mechanical properties) between the filler and the polymer often lead to poor interfacial compatibility, resulting in the formation of non-selective pores at the interface and ultimately reducing the selectivity of the membrane. Although functionalizing the filler (such as grafting polymer chains or modifying functional groups) can enhance the interaction between the filler and the polymer and thus improve the interfacial compatibility of the mixed matrix membrane, the effect is somewhat affected by the limitations in uniformity and controllability of the functionalization process.

[0005] Poor dispersibility of fillers: Most nanofillers (such as MOF, COF and zeolite) have low solubility and poor dispersibility in organic solvents. Even after mechanical stirring or ultrasonic treatment, they are still prone to forming aggregates, which can destroy the continuous separation channels of the membrane. The differences between gas molecules are very small, only at the sub-angstrom level. Any defects in the membrane (such as voids formed by agglomeration or non-selective pores at the interface) can lead to the failure of "selective permeation" and severely reduce its gas separation capacity.

[0006] Therefore, developing membrane materials that combine high permeability, ultra-high selectivity, excellent stability, and ease of large-scale preparation is the core requirement for breaking through the current bottlenecks in the industrial application of gas separation technology. Summary of the Invention

[0007] To address the challenges of balancing permeability and selectivity in traditional polymer membranes, the poor mechanical properties and limited large-scale application of molecular sieve membranes, and the reduced separation performance due to poor interfacial compatibility and insufficient packing dispersion in mixed matrix membranes, this invention proposes a gas separation mixed matrix membrane and its preparation method. This membrane is prepared using a soluble porous material and a polymer matrix. By introducing a porous material with sieve cavities into the polymer matrix, and utilizing the hydrogen bonding between the porous material and the polymer chains, the submicroporous structure of the mixed matrix membrane is adjusted, and the interchain spacing is reduced to increase the transport resistance of N2 and CH4 within the membrane. Simultaneously, the specific cavity size of the porous material creates special transport channels for He, H2, and CO2, thereby improving permeability and offsetting the negative impact of increased chain packing density. Ultimately, a gas separation membrane with ultra-high selectivity for He / N2, He / CH4, H2 / N2, H2 / CH4, CO2 / N2, and CO2 / CH4 is obtained.

[0008] This invention aims to provide a gas separation mixed matrix membrane that combines high He purification performance, hydrogen purification performance, natural gas decarbonization and upgrading performance, and carbon capture performance. The preparation method of this membrane is simple, highly reproducible, and easy to scale up for large-scale production. It provides a more energy-efficient and low-cost alternative solution for the industrial application of helium extraction from natural gas, methane extraction from biogas and natural gas, hydrogen energy purification, and carbon capture.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: This invention first discloses a gas separation mixed matrix membrane, characterized in that the mixed matrix membrane comprises a polymer matrix and a porous material; The pore material is selected from at least one of nitrogen-containing heterocyclic alkanes (Cyclen), calixarene (CA), columnar aromatics (PA), cyclodextrin (CD), cucurbituril (CB), porous organic cages (POC), metal-organic cages (MOC), porous aromatic frameworks (PAF), covalent organic frameworks (COF), metal-organic frameworks (MOF), hydrogen-bonded organic frameworks (HOF), porphyrins (TAPP), and crown ethers (CE), and is used as a filler for the mixed matrix membrane; The polymer matrix is ​​selected from at least one of polyamide (PA), polyimide (PI), polyetherimide (PEI), polysulfone (PSF), polyethersulfone (PES), polyester fiber (PET), polypyrrole (PPY), polyphenylene ether (PPO), polybenzimidazole (PBI), polycarbonate (PC), polyetheretherketone (PEEK), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyacrylamide (PAM), cellulose acetate (CA), self-porous polymer (PIM-1), and block polyetheramide (Pebax 1657), and is used as the matrix material of the mixed matrix membrane.

[0010] Preferably, the mass of the porous material is 0.1 wt% to 80 wt% of the mass of the polymer matrix.

[0011] This invention further discloses a method for preparing the gas separation mixing matrix membrane, comprising the following steps: S1. Disperse the porous material in a solvent and sonicate it for 0.5 to 5 hours to completely dissolve it, thus obtaining a filler solution.

[0012] S2. Disperse the polymer matrix in a solvent, sonicate for 0.5 to 5 hours and / or heat and stir in an oil bath at 50 to 200°C for 1 to 48 hours to completely dissolve it, and then filter it using a syringe equipped with a 0.1 μm to 1 μm PTFE filter head to remove impurities and obtain a pure polymer matrix solution.

[0013] S3. Divide the polymer matrix solution obtained in step S2 into 5 equal parts; first add the first part of the polymer matrix solution to the filler solution obtained in step S1, and sonicate the mixture for 0.5 to 5 hours; after sonication, add the second part of the polymer matrix solution, and then stir and mix at a speed of 300 to 1000 rpm; during stirring, add the remaining 3 parts of the polymer matrix solution at equal intervals, and the total stirring time is 1 to 48 hours; after all the solutions have been added and stirred, sonicate the mixture again for 0.5 to 5 hours to finally obtain a uniformly dispersed casting solution.

[0014] S4. Using a pipette, slowly inject the casting solution obtained in step S3 into a clean petri dish. Place the dish in a vacuum oven at room temperature, cover the surface with perforated aluminum foil, and allow the solvent to evaporate (temperature 0-200℃, time 1-48 hours). After film formation, wait for the vacuum oven to cool to room temperature, slowly release the vacuum, and remove the resulting mixed matrix film.

[0015] S5. Soak the mixed matrix membrane obtained in step S4 in methanol for 1 to 48 hours. After soaking, take it out and put it in a vacuum oven to dry (temperature 30 to 200°C, time 1 to 24 hours). After drying, let it cool naturally to room temperature and take it out to obtain the final gas separation mixed matrix membrane.

[0016] Preferably, the solvent used in steps S1 and S2 is the same and can be at least one of N,N-dimethylformamide, chloroform, dichloromethane, N-methylpyrrolidone, dimethyl sulfoxide, phenol, methanol, formic acid, acetonitrile, dimethylacetamide, m-cresol, tetrahydrofuran, acetic acid, benzene, ethyl acetate, acetone, butanone, decahydronaphthalene, diethyl ether, tetrachloroethane, hexafluoroisopropanol, trifluoroacetic acid, concentrated sulfuric acid, biphenyl, copper ammonia solution, cyclohexane, cyclohexanone, N-methylmorpholine-N-oxide, glycerol, ethanol, and water.

[0017] The present invention also discloses the application of the mixed matrix membrane prepared according to the above preparation method in gas separation, specifically it can be used for helium separation, hydrogen purification, natural gas purification, biogas purification and / or carbon capture, and is particularly suitable for the separation of He / N2, He / CH4, H2 / N2, H2 / CH4, CO2 / N2, and CO2 / CH4.

[0018] The basic principle of this invention is as follows: The porous material selected in this invention has good solubility in organic solvents, which effectively avoids the problem of filler agglomeration and the formation of non-selective defects in the membrane. Simultaneously, the porous material selected in this invention can form strong hydrogen bonds with the polymer material, which on the one hand enhances the interfacial compatibility between the two phases and reduces the formation of non-selective pores at the interface; on the other hand, it reduces the interchain spacing of the polymer material, increasing the transport resistance of N2 and CH4 within the membrane. Furthermore, the cavity structure of the porous material with sieving function can create special transport channels for He, H2, and CO2, improving their permeability. Therefore, a gas separation membrane with ultra-high selectivity for He / N2, He / CH4, H2 / N2, H2 / CH4, CO2 / N2, and CO2 / CH4 is ultimately obtained.

[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention introduces a soluble porous material into a polymer matrix. The hydrogen bonding between the two significantly enhances the interfacial compatibility between the filler and the polymer, effectively overcoming the interfacial defects and non-selective pore formation caused by filler agglomeration present in traditional mixed matrix membranes. Simultaneously, this invention utilizes hydrogen bonding to adjust the chain packing density of the polymer, optimizing the membrane's microporous structure, significantly increasing the number and connectivity of gas transport channels, thereby significantly improving the permeability of small gases (He, H2, CO2) and the selectivity for He / N2, He / CH4, H2 / N2, H2 / CH4, CO2 / N2, and CO2 / CH4. Furthermore, the membrane exhibits strong stability over a wide temperature range (0–100°C) and pressures up to 30 Bar. The membrane preparation process is simple, easily scalable, and the membrane shows minimal decrease in gas permeability while significantly improving selectivity during long-term use—a characteristic beneficial for its industrial application. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 The images show SEM cross-sectional views of the membranes obtained in Comparative Example 1 and Examples 2-4. In the images, (a) to (d) correspond to the samples obtained in Comparative Example 1 and Examples 2-4, respectively.

[0022] Figure 2 The pore size distribution diagrams are for the membranes obtained in Examples 3, 4 and Comparative Example 1. Detailed Implementation

[0023] The technical solution of the present invention will be described in detail below with reference to specific embodiments of the present invention. However, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0024] Example 1 In this embodiment, a gas separation mixed matrix membrane was prepared using polyimide (PI) resin micropowder as the polymer matrix and 1,4,7,10-tetraazacyclododecane as the pore material, following the steps below: S1. Weigh 0.001 g of 1,4,7,10-tetraazacyclododecane particles, disperse them in 6 g of DMF, and sonicate for 0.5 hours to make them evenly dispersed, to obtain a filler solution (a clear, transparent, colorless solution).

[0025] S2. Weigh 0.1 g of polyimide (PI) resin micro powder, disperse it in 4 g of DMF, sonicate it for 0.5 hours to completely dissolve it, and then filter it using a syringe equipped with a 0.1 μm PTFE filter head to remove impurities and obtain a pure polymer matrix solution.

[0026] S3. Divide the polymer matrix solution obtained in step S2 into 5 equal parts; first add the first part of the polymer matrix solution to the filler solution obtained in step S1, and sonicate the mixture for 0.5 hours; after sonication, add the second part of the polymer matrix solution, and then stir and mix at room temperature at a speed of 420 rpm; during the stirring process, add the remaining 3 parts of the polymer matrix solution every 2 hours, and the total stirring time is 10 hours; after all the solutions have been added and stirred, sonicate the mixture again for 0.5 hours to finally obtain a uniformly dispersed casting solution.

[0027] S4. Using a pipette, slowly inject the casting solution obtained in step S3 into a clean petri dish, place it in a vacuum oven at room temperature, cover the surface with perforated aluminum foil, and allow the solvent to evaporate and form a film at 120℃ / 8 h. After film formation, cool to room temperature and remove to obtain a mixed matrix film.

[0028] S5. Soak the mixed matrix membrane obtained in step S4 in methanol for 10 hours. After soaking, take it out and put it in a vacuum oven at 120℃ for 5 hours to dry. After drying, let it cool naturally to room temperature and take it out to obtain the final gas separation mixed matrix membrane, named PI-Cy-1% (the mass of the pore material is 1wt% of the mass of the polymer matrix).

[0029] Example 2 In this embodiment, a gas separation mixed matrix membrane was prepared using the same process steps and conditions as in Example 1. The only difference was that the mass of the 1,4,7,10-tetraazacyclododecane particles in step S1 was 0.003 g, and the resulting membrane was named PI-Cy-3.

[0030] Example 3 In this embodiment, a gas separation mixed matrix membrane was prepared using the same process steps and conditions as in Example 1. The only difference was that the mass of the 1,4,7,10-tetraazacyclododecane particles in step S1 was 0.005 g, and the resulting membrane was named PI-Cy-5.

[0031] Example 4 In this embodiment, a gas separation mixed matrix membrane was prepared using the same process steps and conditions as in Example 1. The only difference was that the mass of the 1,4,7,10-tetraazacyclododecane particles in step S1 was 0.010 g, and the resulting membrane was named PI-Cy-10.

[0032] Example 5 In this embodiment, a gas separation mixed matrix membrane was prepared using the same process steps and conditions as in Example 1. The only difference was that the mass of the 1,4,7,10-tetraazacyclododecane particles in step S1 was 0.015 g, and the resulting membrane was named PI-Cy-15.

[0033] Example 6 In this embodiment, a gas separation mixed matrix membrane was prepared using the same process steps and conditions as in Example 1. The only difference was that 0.003 g of cucurbita (CB) particles were used as the pore material in step S1, and the resulting membrane was named PI-CB-3.

[0034] Example 7 In this embodiment, a gas separation mixed matrix membrane was prepared using the same process steps and conditions as in Example 1. The only difference was that 0.003 g of porphyrin (TAPP) particles were used as the pore material in step S1, and the resulting membrane was named PI-TAPP-3.

[0035] Example 8 In this embodiment, a gas separation mixed matrix membrane was prepared using the same process steps and conditions as in Example 1. The only difference was that in step S1, 0.003 g of calixarene (CA) particles were used as the pore material, and the resulting membrane was named PI-CA-3.

[0036] Example 9 In this embodiment, a gas separation mixed matrix membrane was prepared using the same process steps and conditions as in Example 1. The only difference was that 0.003 g of cyclodextrin (CD) particles were used as the pore material in step S1, and the resulting membrane was named PI-CD-3.

[0037] Example 10 In this embodiment, a gas separation mixed matrix membrane was prepared using block polyether amide (Pebax 1657) as the polymer matrix and crown ether (CE) as the pore material, following the steps below: S1. Weigh 0.0135 g of crown ether particles and disperse them in a 3 g EtOH / H2O (volume ratio 7:3) mixed solution. Sonicate for 0.5 hours to disperse them evenly and obtain a clear and transparent filler solution.

[0038] S2. Weigh 0.45 g of block polyetheramide particles and add them to 15 g of EtOH / H2O (volume ratio 7:3) mixed solution. Heat and stir in an oil bath at 80℃ for 10 hours at a stirring speed of 420 rpm until completely dissolved. Then filter the solution using a syringe equipped with a 0.15 μm PTFE filter head to remove impurities and obtain a polymer matrix solution.

[0039] S3, Same as Example 1.

[0040] S4, Same as in Example 1.

[0041] S5. Soak the mixed matrix membrane obtained in step S4 in methanol for 10 hours. After soaking, take it out and put it in a vacuum oven at 80℃ / 8 h for drying. After drying, let it cool naturally to room temperature and take it out to obtain the final gas separation mixed matrix membrane, named Pe-CE-3.

[0042] Comparative Example 1 This comparative example prepared a pure PI membrane: S1. Weigh 0.1g of polyimide (PI) resin micro powder (Matrimid), disperse it in 4g of DMF, sonicate it for 0.5 hours to completely dissolve it, and then filter it using a syringe equipped with a 0.1 μm PTFE filter head to remove impurities and obtain a pure polymer matrix solution.

[0043] S2. Using a pipette, slowly inject the polymer matrix solution obtained in step S1 into a clean petri dish. Place the dish in a vacuum oven at room temperature, cover the surface with perforated aluminum foil, and allow the solvent to evaporate and form a film at 120℃ for 8 h. After film formation, cool to room temperature and remove the dish to obtain the polymer matrix film.

[0044] S3. Soak the polymer matrix membrane obtained in step S2 in methanol for 10 hours. After soaking, take it out and put it in a vacuum oven at 120℃ for 5 hours to dry. After drying, let it cool naturally to room temperature and take it out to obtain the final pure PI matrix membrane.

[0045] Comparative Example 2 This comparative example prepared pure Pe membrane: S1. Weigh 0.45g of block polyetheramide particles (Pebax 1657) and add them to 15g of EtOH / H2O (volume ratio 7:3) mixed solution. Heat and stir in an oil bath at 80℃ for 10 hours at a stirring speed of 420 rpm until completely dissolved. Then filter the solution using a syringe equipped with a 0.15 μm PTFE filter head to remove impurities and obtain a polymer matrix solution.

[0046] S2. Using a pipette, slowly inject the polymer matrix solution obtained in step S1 into a clean petri dish. Place the dish in a vacuum oven at room temperature, cover the surface with perforated aluminum foil, and allow the solvent to evaporate and form a film at 120℃ for 8 h. After film formation, cool to room temperature and remove the dish to obtain a pure Pe matrix film.

[0047] S3. Soak the pure Pe matrix membrane obtained in step S2 in methanol for 10 hours. After soaking, take it out and put it in a vacuum oven at 80℃ / 8 h for drying. After drying, let it cool naturally to room temperature and take it out to obtain the final pure Pe matrix membrane.

[0048] Figure 1 The cross-sectional microstructures of the films obtained in Comparative Example 1 and Examples 3–5 were displayed using field emission scanning electron microscopy (FESEM). At low Cy loading levels (≤5%), the PI-Cy films exhibited a dense and smooth cross-section. As the Cy loading increased to 10%, a lamellar tearing structure appeared in the film cross-section, indicating a continuous strengthening of the hydrogen bonding interaction between the PI chains and Cy. All PI-Cy films showed a uniform cross-section at 50,000 magnification, with no aggregated or discrete particulate phases observed, confirming the existence of a continuous single-phase structure within the films and the molecular-level uniform distribution of Cy within the films.

[0049] Figure 2The pore size distribution of the membranes obtained in Comparative Example 1 and Examples 3-4 was characterized by combining hydrogen adsorption experiments. The micropore size in the PI membrane was mainly distributed at 6.89 Å, with a small number of ultramicropores of 3.87 Å. In contrast, the micropore sizes of the PI-Cy-5% membrane and the PI-Cy-10% membrane were even smaller, approximately 6.28 Å and 6.48 Å, respectively. The reduction in the micropore size of the PI-Cy membrane indicates that the hydrogen bonding between Cy and PI effectively modulates the micropore structure of the membrane. This pore size regulation enhances the molecular sieving performance of the PI-Cy membrane. With increasing Cy content, the content of ultramicropores of approximately 3.87 Å in the PI-Cy membrane gradually increases. Numerous studies have shown that increasing the content of ultramicropores in the membrane can generally significantly improve its gas molecular sieving ability. As shown in Tables 1-2, when the Cy loading is ≤5%, the selectivity of the membrane for He / CH4 is significantly enhanced with increasing Cy content. However, excessive Cy dispersion in the PI chains leads to increased inter-chain spacing, resulting in non-selective pores larger than CH4. This reduces the membrane's selectivity for He / CH4. Therefore, once the Cy loading reaches 5%, further increases in its content decrease the He / CH4 selectivity. Consequently, the permeability of small molecule gases gradually increases with increasing Cy content. After adding Cy, new ultramicropores with a size of approximately 3.20 Å appeared in the membrane, a value highly consistent with the theoretical value of the Cy molecular window. This indicates that Cy further enhances the membrane's molecular sieving performance by forming ultramicropores with gas molecule recognition capabilities. These ultramicropores create more and longer transport channels for He, significantly improving He transport capacity and gas separation capacity. Thus, the PI-Cy membrane achieves satisfactory sieving performance while maintaining good permeability.

[0050] Referring to patent CN 118987987A, the performance of the membranes obtained in the above embodiments and comparative examples was tested using a membrane carbon capture gas permeability testing and evaluation device at 25°C and 1 Bar. The results are shown in Tables 1 to 6.

[0051] Table 1 Gas permeability data for Examples 1-10 and Comparative Examples 1-2 (average value taken from tests of at least three samples)

[0052] Note: 1 Barrer = 1 × 10 -10 cm 3 (STP)•cm•cm -2 •s -1 •cmHg -1 .

[0053] Table 2 Gas selectivity data for Examples 1-10 and Comparative Examples 1-2 (average value taken from at least three samples tested).

[0054] Table 3 Gas permeability and selectivity data of Example 3 at 1.0 Bar pressure and different temperatures (average value of at least three samples tested).

[0055] Table 4. Gas permeability and selectivity data of Example 3 at 25°C and different pressures (average value of at least three samples tested).

[0056] Table 5 Gas permeability data of Example 3 during aging at 25°C and 1.0 Bar pressure (average value of at least three samples tested).

[0057] Table 6 Selectivity data of Example 3 during aging at 25°C and 1.0 Bar pressure (average of at least three samples tested).

[0058] Table 1-2 compares the gas transport performance of pure Pe membrane (Comparative Example 2) and Pe-CE-3% membrane (Example 10). The CO2 transport efficiency and CO2 / N2 selectivity of the Pe-CE-3% membrane are significantly higher than those of the pure Pe membrane. The significantly enhanced gas transport and separation capabilities of the Pe-CE-3% membrane are attributed to the molecular sieving ability of CE and the hydrogen bond network formed between CE and Pebax. The selectivity window of CE maintains the patency of the CO2 transport channel, while the hydrogen bond network enhances the interfacial compatibility between Pe and CE and inhibits the formation of non-selective pores within the membrane. The synergistic effect of these two factors improves the CO2 transport efficiency and CO2 / N2 separation selectivity of the Pe-CE-3% membrane.

[0059] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A gas separation mixing matrix membrane, characterized in that: The hybrid matrix membrane comprises a polymer matrix and a porous material; The pore material is selected from at least one of nitrogen-containing heterocyclic alkanes, calixarenes, columnar aromatics, cyclodextrins, cucurbita, porous organic cages, metal organic cages, porous aromatic frameworks, covalent organic frameworks, metal organic frameworks, hydrogen-bonded organic frameworks, porphyrins, and crown ethers, and is used as a filler for the mixed matrix membrane. The polymer matrix is ​​selected from at least one of polyamide, polyimide, polyetherimide, polysulfone, polyethersulfone, polyester fiber, polypyrrole, polyphenylene ether, polybenzimidazole, polycarbonate, polyether ether ketone, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl alcohol, polyacrylonitrile, polyacrylamide, cellulose acetate, microporous polymer PIM-1, and block polyether amide Pebax 1657, and is used as the matrix material for the hybrid matrix membrane.

2. The gas separation mixing matrix membrane according to claim 1, characterized in that: The mass of the porous material is 0.1 wt% to 80 wt% of the mass of the polymer matrix.

3. A method for preparing the gas separation mixing matrix membrane according to claim 1 or 2, characterized in that, Includes the following steps: S1. Disperse the porous material in a solvent and sonicate until dissolved to obtain a filler solution; S2. Disperse the polymer matrix in a solvent, sonicate and / or heat and stir until dissolved, then filter using a syringe equipped with a 0.1 μm to 1 μm PTFE filter head to obtain a pure polymer matrix solution; S3. The filler solution obtained in step S1 is subjected to ultrasonic-stirring-re-ultrasonic treatment, and the polymer matrix solution obtained in step S2 is added in multiple batches during the treatment process to finally obtain a uniformly dispersed casting solution. S4. Pour the casting solution obtained in step S3 into a clean petri dish, then place the petri dish in a vacuum oven to evaporate the solvent, and obtain a mixed matrix film. After naturally cooling to room temperature, remove the film. S5. Soak the mixed matrix membrane obtained in step S4 in methanol for 1 to 48 hours. After soaking, take it out and put it in a vacuum oven to dry. After drying, let it cool naturally to room temperature and take it out to obtain the final gas separation mixed matrix membrane.

4. The preparation method according to claim 3, characterized in that, The solvents used in steps S1 and S2 are selected from at least one of N,N-dimethylformamide, chloroform, dichloromethane, N-methylpyrrolidone, dimethyl sulfoxide, phenol, methanol, formic acid, acetonitrile, dimethylacetamide, m-cresol, tetrahydrofuran, acetic acid, benzene, ethyl acetate, acetone, butanone, decahydronaphthalene, diethyl ether, tetrachloroethane, hexafluoroisopropanol, trifluoroacetic acid, concentrated sulfuric acid, biphenyl, copper ammonia solution, cyclohexane, cyclohexanone, N-methylmorpholine-N-oxide, glycerol, ethanol, and water.

5. The preparation method according to claim 3, characterized in that: The ultrasonic treatment time in steps S1 to S3 is set independently for each group from 0.5 to 5 hours; the stirring time in step S3 is from 1 to 48 hours, and the rotation speed is from 300 to 1000 rpm.

6. The preparation method according to claim 3, characterized in that, The specific method of step S3 is as follows: the polymer matrix solution is divided into 5 equal parts; the first part of the polymer matrix solution is added to the filler solution, and the mixture is ultrasonically treated. After the ultrasound was completed, the second part of the polymer matrix solution was added, followed by stirring and mixing; during the stirring process, the remaining 3 parts of the polymer matrix solution were added every 2 hours. After all the solutions have been added and stirred, the mixture is ultrasonically treated again to finally obtain a uniformly dispersed casting solution.

7. The preparation method according to claim 3, characterized in that: In step S4, the solvent evaporation temperature is 0–200°C and the time is 1–48 hours.

8. The preparation method according to claim 3, characterized in that: In step S5, the drying temperature is 30~200℃ and the time is 1~24 hours.

9. The application of the gas separation mixed matrix membrane according to claim 1 or 2 in helium separation, hydrogen purification, natural gas purification, biogas purification and / or carbon capture.

10. The application according to claim 9, characterized in that, The hybrid matrix membrane is used for the separation of He / N2, He / CH4, H2 / N2, H2 / CH4, CO2 / N2 and / or CO2 / CH4.

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