Preparation and application of porous liquid mixed matrix membranes

Abstract

The application belongs to the field of membrane separation, and particularly relates to a preparation method and application of a porous liquid mixed matrix membrane; the application utilizes the adjustable pore size characteristics of a metal organic framework, coats various ionic liquids in a hydroxyl zirconium metal framework, and then covalently grafts polyether amine on the surface of the hydroxyl zirconium metal organic framework, utilizes the polyether amine to increase the steric hindrance of the surface of the metal organic framework, reduces the agglomeration of nanoparticles, and improves the dispersity of the nanoparticles in the polymer matrix; the obtained mixed matrix membrane not only contains the selective advantages of the metal organic framework, the ionic liquid and the polyether amine on carbon dioxide, but also further improves the permeability of the membrane to carbon dioxide molecules.

Description

Technical Field

[0001] This invention relates to the technical field of membrane separation, and in particular to a method for preparing and applying a porous liquid mixing matrix membrane. Background Technology

[0002] The detrimental effects of carbon dioxide on the environment are well-known, yet as an abundant carbon resource, it is widely used in various chemical industries. Therefore, how to efficiently recycle and utilize carbon dioxide has become an urgent problem to be solved in this era. Among existing technologies, membrane separation stands out due to its advantages such as low energy consumption, environmental friendliness, and simple equipment. Polyether block amide-1657, in particular, has become a widely used membrane material due to its excellent comprehensive performance and high gas selectivity. However, how to overcome the limiting relationship between permeability and selectivity, i.e., the Robles upper limit, has now become a common standard for evaluating gas separation membranes.

[0003] Metal-organic frameworks (MOFs) coated with ionic liquids refer to filling the MOF with ionic liquids. This increases the adsorption and dissolution capacity for carbon dioxide while reducing the passage of other large molecular gases, thus attracting widespread attention. Currently, zirconium-based MOFs and ionic liquids are commonly used to modify gas separation membranes. However, zirconium-based MOF membranes still have problems such as poor mechanical properties, poor compatibility with polymer matrices, easy aggregation within the membrane, easy breakage under high pressure, and significant influence of pressure and temperature on carbon dioxide permeation flux. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a porous liquid-mixed matrix membrane and its application, so as to alleviate the technical problems existing in the prior art where zirconium-based metal-organic frameworks and ionic liquids are used to modify gas separation membranes. Due to the tendency of zirconium-based metal-organic framework membranes to aggregate within the membrane, the compatibility between the membrane and the polymer matrix is ​​poor, and the membrane is prone to damage under high pressure.

[0005] To address the aforementioned technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] The first aspect of this invention provides a method for preparing a porous liquid mixing matrix membrane, comprising the following steps:

[0007] S10. Taking advantage of the temperature-dependent adjustable pore size of the metal-organic framework, after coating the metal-organic framework with an ionic liquid at a first temperature, polyetheramine is grafted onto the surface of the metal-organic framework in a weakly alkaline environment to form a polyetheramine-modified metal-organic framework coated with an ionic liquid system with a core-shell structure.

[0008] S20. The polyetheramine-modified metal-organic framework-coated ionic liquid system obtained in step S10 is added to the polyether block amide to obtain the casting solution, which is then heated and stirred in an oil bath.

[0009] The well-stirred casting solution was poured into a PTFE plate using a casting method. After being subjected to room temperature vacuum treatment and degassing by heating, a mixed matrix membrane containing polyetheramine-modified metal-organic framework-coated ionic liquid and polyether block amide was obtained.

[0010] In some modified embodiments of the first aspect of the present invention, in step S10, the ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate; 1-octyl-3-methylimidazolium hexafluorophosphate; 1-butyl-3-methylimidazolium tetrafluoroborate; 1-octyl-3-methylimidazolium tetrafluoroborate.

[0011] The metal-organic framework is zirconium phthalate metal-organic framework; and the ionic liquid is coated on the metal-organic framework to form a zirconium phthalate coated ionic liquid system;

[0012] The polyetheramine includes any one of polyetheramine M1000, polyetheramine M600, polyetheramine M2070, polyetheramine D2000, polyetheramine T5000, and polyetheramine T403.

[0013] In some modified embodiments of the first aspect of the present invention, in step S20, the mass fractions of the polyetheramine modified metal-organic framework coated ionic liquid system are 0, 1%, 2%, 3%, 4%, and 5%, respectively.

[0014] In some modified embodiments of the first aspect of the present invention, in step S20, the oil bath heating conditions are 50~80°C, and the oil bath heating and stirring time is 8~16 hours.

[0015] In some modified embodiments of the first aspect of the present invention, in step S20, the vacuum pressure of the room temperature vacuum treatment is between 0.01 and 0.02 MPa, and the vacuuming time is between 20 and 24 hours.

[0016] In some modified embodiments of the first aspect of the present invention, when the required mixing matrix membrane is used for a mixture containing carbon dioxide, the transmembrane pressure difference of the required mixing matrix membrane is 0.1~0.5 MPa and the operating temperature is 30~60°C.

[0017] Compared to existing technologies, the method of coating ionic liquids with zirconium-based metal-organic frameworks (MOFs) using polyetheramine to form a core-shell structure, and then blending it with polyether block amides to prepare a mixed matrix membrane, achieves the following results: By covalently grafting polyetheramine onto the surface of the zirconium-based MOF, the polyetheramine increases the steric hindrance of the MOF surface, reduces nanoparticle aggregation, and improves its dispersion in the polymer matrix. This further promotes the spatial stability of the particles, enhances gas permeability and selectivity, and alleviates the technical problems of poor compatibility between the zirconium-based MOF membrane and the polymer matrix, and the membrane's susceptibility to damage under high pressure. This method effectively inhibits the aggregation of zirconium-based MOF-coated ionic liquids and improves the gas separation performance of the membrane material. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0019] Figure 1 A schematic diagram illustrating the preparation method and application of a porous liquid mixing matrix membrane provided in this embodiment of the invention;

[0020] Figure 2 The present invention provides a method for preparing a porous liquid mixing matrix membrane and its application, which involves a dehydration reaction between the amine groups of polyetheramine and the hydroxyl groups of a metal-organic framework.

[0021] Figure 3 A method for preparing a porous liquid mixing matrix membrane according to an embodiment of the present invention and its application requirements; a comparison of the separation performance of the mixing matrix membrane with that of the Robertson line.

[0022] Figure 4 This is a schematic diagram of an experimental process for preparing a porous liquid-mixed matrix membrane and its application in separating carbon dioxide gas, as provided in an embodiment of the present invention.

[0023] Wherein: 1-Carbon dioxide cylinder; 2-Nitrogen cylinder; 3-Methane cylinder; 4-Oxygen cylinder; 5-Pressure reducing valve; 6-Needle valve; 7-Control valve; 8-Digital pressure gauge; 9-Thermostatic chamber; 10-Membrane apparatus; 11-Pressure relief valve; 12-Soap bubble flow meter;

[0024] 101-Metal-organic framework; 102-Ionic liquid; 103-Zirconium phthalate-coated ionic liquid system; 104-Polyetheramine; 105-Polyether block amide; 106-Polyetheramine-modified metal-organic framework-coated ionic liquid system; 107-Carbon dioxide; 111-Monoamine; 112-Diamino; 113-Triamino; 114-Polyetheramine (monoamine)-modified zirconium phthalate-coated ionic liquid system; 115-Polyetheramine (diamino)-modified zirconium phthalate-coated ionic liquid system; 116-Polyetheramine (triamino)-modified zirconium phthalate-coated ionic liquid system. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0027] like Figure 1 As shown, this invention provides a method for preparing and applying a porous liquid mixing matrix membrane, comprising the following steps:

[0028] S10. Taking advantage of the temperature-dependent adjustable pore size of the metal-organic framework 101, under the action of a first temperature, after coating the metal-organic framework 102 with ionic liquid 102, in a weakly alkaline environment, grafting polyetheramine 104 onto the surface of the metal-organic framework 101 to form a polyetheramine 104 modified metal-organic framework coated with ionic liquid system 106 with core-shell structure.

[0029] S20. The polyether amine metal-organic framework coated ionic liquid system 106 obtained in step S10 is added to polyether block amide 105 to obtain a casting solution, which is then heated and stirred in an oil bath.

[0030] The well-stirred casting solution was poured into a PTFE plate using a casting method. After being subjected to room temperature vacuum treatment and degassing by heating, the desired mixed matrix membrane containing polyetheramine modified metal-organic framework coated ionic liquid 106 and polyether block amide 105 was obtained.

[0031] A polyetheramine-modified metal-organic framework (MOF) coated with an ionic liquid was modified with polyetheramine 104 to form a core-shell structured MOF-coated ionic liquid system 106. This system was then blended with polyether block amide 105 to prepare a mixed matrix membrane. By covalently grafting polyetheramine 104 onto the surface of the MOF 101, the polyetheramine 104 increases the steric hindrance of the MOF 101 surface, reduces nanoparticle aggregation, and improves its dispersion in the polymer matrix. This further promotes the spatial stability of the particles, enhances gas permeability and selectivity, and alleviates the technical problems of poor compatibility between the MOF 101 membrane and the polymer matrix, and easy membrane damage under high pressure, as present in existing technologies. This achieves the technical effect of inhibiting the aggregation of the MOF 101-coated ionic liquid and improving the gas separation performance of the membrane material.

[0032] Taking polyetheramine 104D2000 as an example, the synthesis principle and mechanism of other types of polyetheramine 104 (M600, M1000, M2070, T403, T5000) are consistent. In polyether block amide 105 (Pebax-1657), the polyether group has a special affinity for carbon dioxide 107 gas, making it easy for carbon dioxide 107 to be adsorbed and dissolved on the membrane surface. 1-Butyl-3-methylimidazolium hexafluorophosphate; 1-octyl-3-methylimidazolium hexafluorophosphate; 1-Butyl-3-methylimidazolium tetrafluoroborate; 1-octyl-3-methylimidazolium tetrafluoroborate are strongly basic. The nitrogen atom on the imidazole is a Lewis base, while carbon dioxide 107 is a Lewis acid; therefore, a Lewis acid-base interaction exists between the two. The amino group of polyetheramine 104 is a basic group, while carbon dioxide 107 is an acidic gas. The interaction between the two is strong and reversible, which has a good effect on fixing carbon dioxide 107. Moreover, it can also increase the steric hindrance on the surface of zirconium phthalate metal-organic framework 101 through repulsive force, effectively preventing the aggregation of zirconium phthalate metal-organic framework 101.

[0033] It should be noted that, as Figure 2As shown, the metal-organic framework 101 is a zirconium hydroxide metal-organic framework; and the ionic liquid coats the metal-organic framework to form a zirconium hydroxide-coated ionic liquid system 103. The coating of the metal-organic framework with the ionic liquid is a physical process, and the amino groups of the polyetheramine 104 undergo a dehydration reaction with the hydroxyl groups of the metal-organic framework 101. The pore size of the metal-organic framework 101 is changed by the change of external temperature. The grafting of polyetheramine 104 onto the surface of the metal-organic framework 101 is a chemical reaction. The dehydration reaction occurs through the amino groups of polyetheramine 104 and the hydroxyl groups of the metal-organic framework 101. Polyetheramine 104 was dehydrated to form monoamino 111 and its corresponding polyetheramine (monoamino) modified zirconium phthalate coated ionic liquid system 114; diamino 112 and its corresponding polyetheramine (diamino) modified zirconium phthalate coated ionic liquid system 115; and triamino 113 and its corresponding polyetheramine (triamino) modified zirconium phthalate coated ionic liquid system 116.

[0034] Furthermore, in step S20, the oil bath heating conditions are 50~80℃, and the oil bath heating and stirring time is 8~16 hours.

[0035] By setting the heating conditions to 50~80℃ and the oil bath heating and stirring time to 8~16 hours, the miscibility of the polyether amine modified metal-organic framework coated ionic liquid system 106 with the polyether block amide 105 casting solution and the polyether amine modified metal-organic framework coated ionic liquid system 106 under the influence of stirring time and heating temperature can be better observed. The operating conditions can be optimized to achieve the purpose of preparing a uniform and dense mixed matrix membrane.

[0036] Furthermore, in step S20, the vacuum pressure of the room temperature vacuum treatment is between 0.01 and 0.02 MPa, and the evacuation time is between 20 and 24 hours.

[0037] By using a room temperature vacuum treatment with a vacuum pressure between 0.01 and 0.02 MPa and a vacuuming time between 20 and 24 hours, the plasticizing effect of carbon dioxide 107 in the air on the casting solution during film formation can be better reduced. The long-term vacuum can also better remove the solvent inside the casting solution and the gas molecules adsorbed on the surface.

[0038] like Figure 4 As shown, further, when the required mixed matrix membrane is used for a mixed gas containing carbon dioxide 107, the required transmembrane pressure difference of the mixed matrix membrane is 0.1~0.5 MPa, the operating temperature is 30~60℃, and the separation method is as follows:

[0039] Place the mixed matrix membrane in membrane unit 10. Adjust the temperature control chamber 9 to the required experimental temperature (30-60℃). Adjust the pressure to the required experimental pressure (0.1-0.5 MPa). First, open the control valve 7 of nitrogen cylinder 2 for pre-pressurization for 60 minutes until the digital pressure gauge 8 stabilizes. Observe the increase in the reading of the downstream soap bubble flow meter 12 within a unit time to calculate the nitrogen permeation flux. Then, open the methane cylinder 3 for pre-pressurization for 60 minutes to ensure all nitrogen is expelled and the membrane is pre-pressurized by methane. Observe the increase in the reading of the downstream soap bubble flow meter 12 within a unit time to calculate the methane permeation flux. Next, open the oxygen cylinder 4 for pre-pressurization for 60 minutes to ensure all methane is expelled and the membrane is pre-pressurized by oxygen. Observe the increase in the reading of the downstream soap bubble flow meter 12 within a unit time to calculate the oxygen permeation flux. Finally, pre-pressurize the membrane with CO2 107 cylinder 1 for 60 minutes to ensure all oxygen is removed and the membrane is pre-pressurized by CO2 107. Then, observe the increase in the reading of the downstream soap bubble flowmeter 12 within a unit time period to calculate the CO2 107 permeation flux. After measuring the permeation flux of each gas, the selectivity of CO2 107 / nitrogen and CO2 107 / methane can be determined.

[0040] It should be noted that the above separation method is also equipped with a pressure reducing valve 5, a needle valve 6, and a pressure relief valve 11 to ensure the safe operation of the pipeline.

[0041] Further, in step S10, the ionic liquid 102 is 1-butyl-3-methylimidazolium hexafluorophosphate; 1-octyl-3-methylimidazolium hexafluorophosphate; 1-butyl-3-methylimidazolium tetrafluoroborate; 1-octyl-3-methylimidazolium tetrafluoroborate;

[0042] Polyetheramine 104 includes any one of polyetheramine 104M1000, polyetheramine 104M600, polyetheramine 104M2070, polyetheramine 104D2000, polyetheramine 104T5000, and polyetheramine 104T403.

[0043] Furthermore, in step S20, the mass fractions of the polyetheramine-modified metal-organic framework-coated ionic liquid system 106 are 0, 1%, 2%, 3%, 4%, and 5%, respectively.

[0044] As described above, to verify the selectivity of carbon dioxide 107 / nitrogen and carbon dioxide 107 / methane obtained by the different types of ionic liquids 102, polyetheramine 104, and polyetheramine-modified metal-organic framework-coated ionic liquid systems 109, the following examples are provided in this embodiment:

[0045] Example 1

[0046] (1) Specific synthesis method of zirconium hydroxyphthalate metal-organic framework 101:

[0047] 0.1258 g of zirconium tetrachloride was weighed and dissolved in a mixed solution of N,N-dimethylformamide / concentrated hydrochloric acid (12 mL, 10:2, v / v), and a homogeneous solution was obtained under stirring. Simultaneously, 0.099 g of 2-hydroxyterephthalic acid was dissolved in 10 mL of N,N-dimethylformamide. After mixing thoroughly, the solution was stirred for 30 minutes and transferred to a polytetrafluoroethylene liner. The reaction was carried out at 80 °C for 12 hours. After centrifugation at 8000 rpm for 5 minutes, the sample was washed three times with N,N-dimethylformamide to remove unreacted solute, then washed three times with ethanol to replace the N,N-dimethylformamide. Finally, the synthesized sample was dried in an oven at 60 °C for 12 hours to obtain a pale green powder.

[0048] (2) The specific preparation method for the zirconium hydroxyphthalate metal-organic framework 101-coated ionic liquid is as follows:

[0049] 1 g of zirconium phthalate metal-organic framework 101 powder was added to 15 g of anhydrous ethanol and stirred for about 4 hours. A thin film was placed over the glass beaker to prevent ethanol evaporation during stirring. Then, 1 g of ionic liquid was mixed into the zirconium phthalate metal-organic framework 101 solution, and the mixture was stirred in an oil bath at 80 °C for 4 hours. After cooling to room temperature, the resulting sample was washed three times with N,N-dimethylformamide, and then placed in an oven at 40 °C for 24 hours to obtain a pale green powder.

[0050] (3) Preparation of ionic liquids coated with polyetheramine 104-modified zirconium hydroxyphthalate metal-organic framework:

[0051] 1 g of zirconium phthalate metal-organic framework 101-coated ionic liquid was dissolved in an ethanol and water solution (10 g, 70:30, wt%), and then sonicated for 2 hours. Polyetheramine 104D2000 was then diluted to 15 wt% with ethanol and deionized water, and stirred continuously for 1 hour. All substances were co-mixed at 70°C for 30 hours with continuous stirring. The polymer solution was then filtered through a dialysis tube (7000 MWCO). Finally, the prepared polyetheramine 104D2000-modified zirconium phthalate metal-organic framework 101-coated ionic liquid was stored in a vacuum oven at 50°C for at least 60 hours to remove excess ethanol and deionized water.

[0052] (4) Application of mixed matrix membrane preparation and carbon dioxide 107 gas separation

[0053] Weigh 1g of polyether block amide 105 (Pebax-1657) as the solute, and use ethanol and water (70:30, wt%) as solvents. After mixing the two, seal the mixture in a three-necked flask and place it in a heated magnetic stirrer. Reflux the mixture at 80°C in an oil bath for 4 hours to ensure that the polyether block amide 105 (Pebax-1657) is uniformly dissolved in the mixed solution. The resulting solution is a clear, homogeneous phase. A certain mass fraction of the prepared polyetheramine 104D2000 modified zirconium hydroxyphthalate metal-organic framework 101-coated ionic liquid was added to a homogeneous solution of polyether block amide 105 (Pebax-1657). The temperature was adjusted from 80℃ to 50℃, and the mixture was refluxed and stirred for 8 hours. The stirred casting solution was cooled to room temperature and allowed to stand for degassing for 24 hours. The casting solution was poured onto a PTFE plate using a casting method, ensuring that it was evenly distributed across the entire PTFE plate. The plate was then placed in a vacuum drying oven at room temperature for 20 hours, followed by vacuum drying at 40℃ for 4 hours to remove solvent residue, ultimately obtaining mixed matrix films with different contents.

[0054] Under experimental conditions of 0.1 MPa and 40 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the filler content was 1 wt%, and the permeation flux of carbon dioxide 107 was 85.56 Barrer (1 Barrer = 10⁻⁶). -10 cm 3 (STP)cm / cm 2 The selectivity of carbon dioxide 107 / nitrogen was 71.61, the selectivity of carbon dioxide 107 / methane was 65.82, and the selectivity of carbon dioxide 107 / oxygen was 37.69.

[0055] Under test conditions of 0.1 MPa and 40 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the filler content was 2 wt%, the permeation flux of carbon dioxide 107 was 94.86 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 79.05, the selectivity of carbon dioxide 107 / methane was 67.75, and the selectivity of carbon dioxide 107 / oxygen was 41.61.

[0056] Under test conditions of 0.1 MPa and 40 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the filler content was 3 wt%, the permeation flux of carbon dioxide 107 was 98.75 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 82.62, the selectivity of carbon dioxide 107 / methane was 70.53, and the selectivity of carbon dioxide 107 / oxygen was 43.48.

[0057] Under test conditions of 0.1 MPa and 40 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the filler content was 4 wt%, the permeation flux of carbon dioxide 107 was 83.8 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 68.31, the selectivity of carbon dioxide 107 / methane was 59.86, and the selectivity of carbon dioxide 107 / oxygen was 35.95.

[0058] Under test conditions of 0.1 MPa and 40 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the filler content was 5 wt%, the permeation flux of carbon dioxide 107 was 78.66 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 61.45, the selectivity of carbon dioxide 107 / methane was 56.19, and the selectivity of carbon dioxide 107 / oxygen was 29.34.

[0059] Example 2

[0060] (1) Specific synthesis method of zirconium hydroxyphthalate metal-organic framework 101:

[0061] 0.1258 g of zirconium tetrachloride was weighed and dissolved in a mixed solution of N,N-dimethylformamide / concentrated hydrochloric acid (12 mL, 10:2, v / v), and a homogeneous solution was obtained under stirring. Simultaneously, 0.099 g of 2-hydroxyterephthalic acid was dissolved in 10 mL of N,N-dimethylformamide. After mixing thoroughly, the solution was stirred for 30 minutes and transferred to a polytetrafluoroethylene liner. The reaction was carried out at 80 °C for 12 hours. After centrifugation at 8000 rpm for 5 minutes, the sample was washed three times with N,N-dimethylformamide to remove unreacted solute, then washed three times with ethanol to replace the N,N-dimethylformamide. Finally, the synthesized sample was dried in an oven at 60 °C for 12 hours to obtain a pale green powder.

[0062] (2) The specific preparation method for the zirconium hydroxyphthalate metal-organic framework 101-coated ionic liquid is as follows:

[0063] 1 g of zirconium phthalate metal-organic framework 101 powder was added to 15 g of anhydrous ethanol and stirred for about 4 hours. A thin film was placed over the glass beaker to prevent ethanol evaporation during stirring. Then, 1 g of ionic liquid was mixed into the zirconium phthalate metal-organic framework 101 solution, and the mixture was stirred in an oil bath at 80 °C for 4 hours. After cooling to room temperature, the resulting sample was washed three times with N,N-dimethylformamide, and then placed in an oven at 40 °C for 24 hours to obtain a pale green powder.

[0064] (3) Preparation of ionic liquids coated with polyetheramine 104 modified zirconium hydroxyphthalate metal-organic framework 101:

[0065] 1 g of zirconium phthalate metal-organic framework 101-coated ionic liquid was dissolved in an ethanol and water solution (10 g, 70:30, wt%), and then sonicated for 2 hours. Polyetheramine 104D2000 was then diluted to 15 wt% with ethanol and deionized water, and stirred continuously for 1 hour. All substances were co-mixed at 70°C for 30 hours with continuous stirring. The polymer solution was then filtered through a dialysis tube (7000 MWCO). Finally, the prepared polyetheramine 104D2000-modified zirconium phthalate metal-organic framework 101-coated ionic liquid was stored in a vacuum oven at 50°C for at least 60 hours to remove excess ethanol and deionized water.

[0066] (4) Application of mixed matrix membrane preparation and carbon dioxide 107 gas separation

[0067] Weigh 1g of polyether block amide 105 (Pebax-1657) as the solute, and use ethanol and water (70:30, wt%) as solvents. After mixing the two, seal the mixture in a three-necked flask and place it in a heated magnetic stirrer. Reflux the mixture at 80°C in an oil bath for 4 hours to ensure that the polyether block amide 105 (Pebax-1657) is uniformly dissolved in the mixed solution. The resulting solution is a clear, homogeneous phase. A certain mass fraction of the prepared polyetheramine 104D2000 modified zirconium hydroxyphthalate metal-organic framework 101 coated ionic liquid was added to a homogeneous solution of polyether block amide 105 (Pebax-1657). The temperature was adjusted from 80℃ to 50℃, and the mixture was refluxed and stirred for 8 hours. The stirred casting solution was cooled to room temperature and allowed to stand for degassing for 24 hours. The casting solution was poured onto a PTFE plate using a casting method, ensuring that it was evenly distributed across the entire PTFE plate. The plate was then placed in a vacuum drying oven at room temperature for 20 hours, followed by vacuum drying at 40℃ for 4 hours to remove solvent residue. Finally, a mixed matrix membrane with a filler content of 3wt% was obtained.

[0068] Under test conditions of 0.2 MPa and 30 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the permeation flux of carbon dioxide 107 was 104.56 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 85.13, the selectivity of carbon dioxide 107 / methane was 74.68, and the selectivity of carbon dioxide 107 / oxygen was 44.81.

[0069] Under test conditions of 0.3 MPa and 30 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the permeation flux of carbon dioxide 107 was 109.12 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 77.94, the selectivity of carbon dioxide 107 / methane was 77.94, and the selectivity of carbon dioxide 107 / oxygen was 46.5.

[0070] Under test conditions of 0.4 MPa and 30 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the permeation flux of carbon dioxide 107 was 115.48 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 82.48, the selectivity of carbon dioxide 107 / methane was 82.48, and the selectivity of carbon dioxide 107 / oxygen was 50.51.

[0071] Under experimental conditions of 0.5 MPa and 30 °C, with 1-butyl-3-methylimidazolium hexafluorophosphate as the ionic liquid, the permeation flux of carbon dioxide 107 was 119.85 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 85.61, the selectivity of carbon dioxide 107 / methane was 85.61, and the selectivity of carbon dioxide 107 / oxygen was 57.21.

[0072] Example 3

[0073] (1) Specific synthesis method of zirconium hydroxyphthalate metal-organic framework 101:

[0074] 0.1258 g of zirconium tetrachloride was weighed and dissolved in a mixed solution of N,N-dimethylformamide / concentrated hydrochloric acid (12 mL, 10:2, v / v), and a homogeneous solution was obtained under stirring. Simultaneously, 0.099 g of 2-hydroxyterephthalic acid was dissolved in 10 mL of N,N-dimethylformamide. After mixing thoroughly, the solution was stirred for 30 minutes and transferred to a polytetrafluoroethylene liner. The reaction was carried out at 80 °C for 12 hours. After centrifugation at 8000 rpm for 5 minutes, the sample was washed three times with N,N-dimethylformamide to remove unreacted solute, then washed three times with ethanol to replace the N,N-dimethylformamide. Finally, the synthesized sample was dried in an oven at 60 °C for 12 hours to obtain a pale green powder.

[0075] (2) The specific preparation method for the zirconium hydroxyphthalate metal-organic framework 101-coated ionic liquid is as follows:

[0076] 1 g of zirconium phthalate metal-organic framework 101 powder was added to 15 g of anhydrous ethanol and stirred for about 4 hours. A thin film was placed over the glass beaker to prevent ethanol evaporation during stirring. Then, 1 g of ionic liquid was mixed into the zirconium phthalate metal-organic framework 101 solution, and the mixture was stirred in an oil bath at 80 °C for 4 hours. After cooling to room temperature, the resulting sample was washed three times with N,N-dimethylformamide, and then placed in an oven at 40 °C for 24 hours to obtain a pale green powder.

[0077] (3) Preparation of ionic liquids coated with polyetheramine 104 modified zirconium hydroxyphthalate metal-organic framework 101:

[0078] 1 g of zirconium phthalate metal-organic framework 101-coated ionic liquid was dissolved in an ethanol and water solution (10 g, 70:30, wt%), and then sonicated for 2 hours. Polyetheramine 104D2000 was then diluted to 15 wt% with ethanol and deionized water, and stirred continuously for 1 hour. All substances were co-mixed at 70°C for 30 hours with continuous stirring. The polymer solution was then filtered through a dialysis tube (7000 MWCO). Finally, the prepared polyetheramine 104D2000-modified zirconium phthalate metal-organic framework 101-coated ionic liquid was stored in a vacuum oven at 50°C for at least 60 hours to remove excess ethanol and deionized water.

[0079] (4) Application of mixed matrix membrane preparation and carbon dioxide 107 gas separation

[0080] Weigh 1g of polyether block amide 105 (Pebax-1657) using an electronic balance as the solute. Use ethanol and water (70:30, wt%) as solvents, mix them, and seal the mixture in a three-necked flask. Place the flask in a heated magnetic stirrer and reflux at 80°C in an oil bath for 4 hours to ensure the polyether block amide 105 (Pebax-1657) is uniformly dissolved in the mixed solution. The resulting solution is a clear, homogeneous phase. A certain mass fraction of the prepared polyetheramine 104D2000 modified zirconium hydroxyphthalate metal-organic framework 101 coated ionic liquid was added to a homogeneous solution of polyether block amide 105 (Pebax-1657). The temperature was adjusted from 80℃ to 50℃ and refluxed for 8 hours. The stirred casting solution was cooled to room temperature and allowed to stand for degassing for 24 hours. The casting solution was poured onto a PTFE plate using a casting method, ensuring that it was evenly distributed across the entire PTFE plate. The plate was then placed in a vacuum drying oven at room temperature for 20 hours, followed by vacuum drying at 40℃ for 4 hours to remove solvent residue. Finally, a mixed matrix membrane with a filler content of 1 wt% was obtained.

[0081] Under test conditions of 0.2 MPa and 50 °C, the ionic liquid was 1-octyl-3-methylimidazolium hexafluorophosphate. The permeation flux of carbon dioxide 107 was 86.26 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 78.72, the selectivity of carbon dioxide 107 / methane was 66.35, and the selectivity of carbon dioxide 107 / oxygen was 37.49.

[0082] Under test conditions of 0.2 MPa and 50 °C, the ionic liquid was 1-butyl-3-methylimidazolium tetrafluoroborate. The permeation flux of carbon dioxide 107 was 79.82 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 64.58, the selectivity of carbon dioxide 107 / methane was 59.12, and the selectivity of carbon dioxide 107 / oxygen was 30.75.

[0083] Under test conditions of 0.2 MPa and 50 °C, the ionic liquid was 1-octyl-3-methylimidazolium tetrafluoroborate, the permeation flux of carbon dioxide 107 was 70.09 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 55.09, the selectivity of carbon dioxide 107 / methane was 48.34, and the selectivity of carbon dioxide 107 / oxygen was 26.23.

[0084] Example 4

[0085] The zirconium hydroxyphthalate metal-organic framework 101 prepared in Example 1 (1) and the zirconium hydroxyphthalate metal-organic framework 101 prepared in Example 1 (2) were used to coat the ionic liquid.

[0086] In Example 1 (3), polyetheramine 104D2000 was changed to polyetheramine 104M2070.

[0087] (3) Preparation of ionic liquids coated with polyetheramine 104 modified zirconium hydroxyphthalate metal-organic framework 101:

[0088] 1 g of zirconium phthalate metal-organic framework 101-coated ionic liquid was dissolved in an ethanol and water solution (10 g, 70:30, wt%), and then sonicated for 2 hours. Polyetheramine 104M2070 was then diluted to 15 wt% with ethanol and deionized water, and stirred continuously for 1 hour. All substances were co-mixed at 70°C for 30 hours with continuous stirring. The polymer solution was then filtered through a dialysis tube (7000 MWCO). Finally, the prepared polyetheramine 104M2070-modified zirconium phthalate metal-organic framework 101-coated ionic liquid was stored in a vacuum oven at 50°C for at least 60 hours to remove excess ethanol and deionized water.

[0089] (4) Application of mixed matrix membrane preparation and carbon dioxide 107 gas separation

[0090] Weigh 1g of polyether block amide 105 (Pebax-1657) using an electronic balance as the solute. Use ethanol and water (70:30, wt%) as solvents, mix them, and seal the mixture in a three-necked flask. Place the flask in a heated magnetic stirrer and reflux at 80°C in an oil bath for 4 hours to ensure the polyether block amide 105 (Pebax-1657) is uniformly dissolved in the mixed solution. The resulting solution is a clear, homogeneous phase. A certain mass fraction of the prepared polyetheramine 104M2070 modified zirconium hydroxyphthalate metal-organic framework 101 coated ionic liquid was added to a homogeneous solution of polyether block amide 105 (Pebax-1657). The temperature was adjusted from 80℃ to 50℃, and the mixture was refluxed and stirred for 8 hours. The stirred casting solution was cooled to room temperature and allowed to stand for degassing for 24 hours. The casting solution was poured onto a PTFE plate using a casting method, ensuring that it was evenly distributed across the entire PTFE plate. The plate was then placed in a vacuum drying oven at room temperature for 20 hours, followed by vacuum drying at 40℃ for 4 hours to remove solvent residue. Finally, a mixed matrix membrane with a filler content of 4wt% was obtained.

[0091] Under experimental conditions of 0.5 MPa and 40 °C, with 1-butyl-3-methylimidazolium hexafluorophosphate as the ionic liquid, the permeation flux of carbon dioxide 107 was 117.91 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 93.37, the selectivity of carbon dioxide 107 / methane was 87.34, and the selectivity of carbon dioxide 107 / oxygen was 30.75.

[0092] Under experimental conditions of 0.5 MPa and 40 °C, the ionic liquid was 1-octyl-3-methylimidazolium hexafluorophosphate. The permeation flux of carbon dioxide 107 was 113.08 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 91.59, the selectivity of carbon dioxide 107 / methane was 84.39, and the selectivity of carbon dioxide 107 / oxygen was 26.23.

[0093] Under test conditions of 0.5 MPa and 40 °C, the ionic liquid was 1-butyl-3-methylimidazolium tetrafluoroborate. The permeation flux of carbon dioxide 107 was 115.96 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 94.97, the selectivity of carbon dioxide 107 / methane was 86.54, and the selectivity of carbon dioxide 107 / oxygen was 49.14.

[0094] Under experimental conditions of 0.5 MPa and 40 °C, the ionic liquid was 1-octyl-3-methylimidazolium tetrafluoroborate. The permeation flux of carbon dioxide 107 was 114.72 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 92.37, the selectivity of carbon dioxide 107 / methane was 85.61, and the selectivity of carbon dioxide 107 / oxygen was 48.62.

[0095] Example 5

[0096] Zirconium hydroxyphthalate metal-organic framework 101 was prepared using Example 1 (1).

[0097] The ionic liquid in Example 1 (2) was fixed as 1-octyl-3-methylimidazolium hexafluorophosphate; the polyetheramine 104 in Example 1 (3) was changed to polyetheramine 104 (M1000, T5000, T403, M600).

[0098] (3) Preparation of ionic liquids coated with polyetheramine 104 modified zirconium hydroxyphthalate metal-organic framework 101:

[0099] 1 g of zirconium phthalate metal-organic framework 101-coated ionic liquid was dissolved in an ethanol and water solution (10 g, 70:30, wt%), and then sonicated for 2 hours. The polyetheramine 104 was then diluted to 15 wt% with ethanol and deionized water, and stirred continuously for 1 hour. All substances were co-mixed at 70°C for 30 hours with continuous stirring. The polymer solution was then filtered through dialysis tubes (7000 MWCO for M1000, 14000 MWCO for T5000, and 3500 MWCO for T403 and M600). Finally, the prepared polyetheramine 104-modified zirconium phthalate metal-organic framework 101-coated ionic liquid was stored in a vacuum oven at 50°C for at least 60 hours to remove excess ethanol and deionized water.

[0100] (4) Application of mixed matrix membrane preparation and carbon dioxide 107 gas separation

[0101] Weigh 1g of polyether block amide 105 (Pebax-1657) using an electronic balance as the solute. Use ethanol and water (70:30, wt%) as solvents, mix them, and seal the mixture in a three-necked flask. Place the flask in a heated magnetic stirrer and reflux at 80°C in an oil bath for 4 hours to ensure the polyether block amide 105 (Pebax-1657) is uniformly dissolved in the mixed solution. The resulting solution is a clear, homogeneous phase. A certain mass fraction of the prepared polyetheramine 104 modified zirconium hydroxyphthalate metal-organic framework 101 coated ionic liquid was added to a homogeneous solution of polyether block amide 105 (Pebax-1657). The temperature was adjusted from 80℃ to 50℃, and the mixture was refluxed and stirred for 8 hours. The stirred casting solution was cooled to room temperature and allowed to stand for degassing for 24 hours. The casting solution was poured onto a PTFE plate using a casting method, ensuring that it was evenly distributed across the entire PTFE plate. The plate was then placed in a vacuum drying oven at room temperature for 20 hours, followed by vacuum drying at 40℃ for 4 hours to remove solvent residue. Finally, a mixed matrix membrane with a filler content of 3wt% was obtained.

[0102] Under test conditions of 0.2 MPa and 40 °C, the permeation flux of polyetheramine 104 (polyetheramine 104M1000) and carbon dioxide 107 is 91.59 Barrer, the selectivity of carbon dioxide 107 / nitrogen is 86.26, the selectivity of carbon dioxide 107 / methane is 79.64, and the selectivity of carbon dioxide 107 / oxygen is 45.5.

[0103] Under test conditions of 0.2 MPa and 40 °C, the permeation flux of polyetheramine 104 (polyetheramine 104M600) and carbon dioxide 107 is 65.32 Barrer, the selectivity of carbon dioxide 107 / nitrogen is 55.4, the selectivity of carbon dioxide 107 / methane is 52.36, and the selectivity of carbon dioxide 107 / oxygen is 29.16.

[0104] Under test conditions of 0.2 MPa and 40 °C, the permeation flux of polyetheramine 104 (polyetheramine 104T5000) and carbon dioxide 107 is 89.75 Barrer, the selectivity of carbon dioxide 107 / nitrogen is 87.58, the selectivity of carbon dioxide 107 / methane is 72.96, and the selectivity of carbon dioxide 107 / oxygen is 46.09.

[0105] Under test conditions of 0.2 MPa and 40 °C, the permeation flux of polyetheramine 104 (polyetheramine 104T403) and carbon dioxide 107 is 67.61 Barrer, the selectivity of carbon dioxide 107 / nitrogen is 59.92, the selectivity of carbon dioxide 107 / methane is 56.34, and the selectivity of carbon dioxide 107 / oxygen is 27.23.

[0106] Example 6

[0107] The zirconium hydroxyphthalate metal-organic framework 101 prepared in Example 1 (1) and the zirconium hydroxyphthalate metal-organic framework 101 prepared in Example 1 (2) were used to coat the ionic liquid.

[0108] In Example 1 (3), polyetheramine 104D2000 was changed to polyetheramine 104M1000.

[0109] (3) Preparation of ionic liquids coated with polyetheramine 104 modified zirconium hydroxyphthalate metal-organic framework 101:

[0110] 1 g of zirconium phthalate metal-organic framework 101-coated ionic liquid was dissolved in an ethanol and water solution (10 g, 70:30, wt%), and then sonicated for 2 hours. Polyetheramine 104M1000 was then diluted to 15 wt% with ethanol and deionized water, and stirred continuously for 1 hour. All substances were co-mixed at 70°C for 30 hours with continuous stirring. The polymer solution was then filtered through a dialysis tube (7000 MWCO). Finally, the prepared polyetheramine 104M1000-modified zirconium phthalate metal-organic framework 101-coated ionic liquid was stored in a vacuum oven at 50°C for at least 60 hours to remove excess ethanol and deionized water.

[0111] (4) Application of mixed matrix membrane preparation and carbon dioxide 107 gas separation

[0112] Weigh 1g of polyether block amide 105 (Pebax-1657) using an electronic balance as the solute. Use ethanol and water (70:30, wt%) as solvents, mix them, and seal the mixture in a three-necked flask. Place the flask in a heated magnetic stirrer and reflux at 80°C in an oil bath for 4 hours to ensure the polyether block amide 105 (Pebax-1657) is uniformly dissolved in the mixed solution. The resulting solution is a clear, homogeneous phase. A certain mass fraction of the prepared polyetheramine 104M1000 modified zirconium hydroxyphthalate metal-organic framework 101 coated ionic liquid was added to a homogeneous solution of polyether block amide 105 (Pebax-1657). The temperature was adjusted from 80℃ to 50℃ and refluxed for 8 hours. The stirred casting solution was cooled to room temperature and allowed to stand for degassing for 24 hours. The casting solution was poured onto a PTFE plate using a casting method, ensuring that it was evenly distributed across the entire PTFE plate. The plate was then placed in a vacuum drying oven at room temperature for 20 hours, followed by vacuum drying at 40℃ for 4 hours to remove solvent residue. Finally, a mixed matrix membrane with a filler content of 5wt% was obtained.

[0113] Under test conditions of 0.3 MPa and 60 °C, the ionic liquid was 1-butyl-3-methylimidazolium hexafluorophosphate, the permeation flux of carbon dioxide 107 was 105.7 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 54.63, the selectivity of carbon dioxide 107 / methane was 48.04, and the selectivity of carbon dioxide 107 / oxygen was 28.75.

[0114] Under experimental conditions of 0.3 MPa and 60 °C, the ionic liquid was 1-octyl-3-methylimidazolium hexafluorophosphate. The permeation flux of carbon dioxide 107 was 92.36 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 40.58, the selectivity of carbon dioxide 107 / methane was 36.94, and the selectivity of carbon dioxide 107 / oxygen was 21.36.

[0115] Under test conditions of 0.3 MPa and 60 °C, the ionic liquid was 1-butyl-3-methylimidazolium tetrafluoroborate, the permeation flux of carbon dioxide 107 was 81.05 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 39.67, the selectivity of carbon dioxide 107 / methane was 36.84, and the selectivity of carbon dioxide 107 / oxygen was 20.88.

[0116] Under experimental conditions of 0.3 MPa and 60 °C, the ionic liquid was 1-octyl-3-methylimidazolium tetrafluoroborate, the permeation flux of carbon dioxide 107 was 70.87 Barrer, the selectivity of carbon dioxide 107 / nitrogen was 35.11, the selectivity of carbon dioxide 107 / methane was 32.21, and the selectivity of carbon dioxide 107 / oxygen was 18.47.

[0117] like Figure 3 As shown above, the separation performance of the hybrid matrix membrane has significantly exceeded the Robeson limit in 2008, indicating that the separation performance of the hybrid matrix membrane meets the commercial requirements of this technology.

[0118] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a porous liquid mixing matrix membrane, characterized in that, Includes the following steps: S10. Taking advantage of the temperature-dependent adjustable pore size of the metal-organic framework, after coating the metal-organic framework with an ionic liquid at a first temperature, polyetheramine is grafted onto the surface of the metal-organic framework in a weakly alkaline environment to form a polyetheramine-modified metal-organic framework coated with an ionic liquid system with a core-shell structure. S20. The polyetheramine-modified metal-organic framework-coated ionic liquid system obtained in step S10 is added to the polyether block amide solution to obtain a casting solution, which is then heated and stirred in an oil bath. The well-stirred casting solution was poured into a PTFE plate using a casting method. After being subjected to room temperature vacuum treatment and degassing by heating, a mixed matrix membrane containing polyetheramine-modified metal-organic framework-coated ionic liquid and polyether block amide was obtained.

2. The method for preparing a porous liquid mixing matrix membrane according to claim 1, characterized in that, In step S10, the ionic liquid is 1-butyl-3-methylimidazolium hexafluorophosphate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate or 1-octyl-3-methylimidazolium tetrafluoroborate. The metal-organic framework is zirconium phthalate metal-organic framework; and the ionic liquid is coated on the metal-organic framework to form a zirconium phthalate coated ionic liquid system; The polyetheramine includes any one of polyetheramine M1000, polyetheramine M600, polyetheramine M2070, polyetheramine D2000, polyetheramine T5000, and polyetheramine T403.

3. The method for preparing a porous liquid mixing matrix membrane according to claim 1, characterized in that, In step S20, the mass fractions of the polyetheramine-modified metal-organic framework-coated ionic liquid system in the casting solution are 1%, 2%, 3%, 4%, and 5%, respectively.

4. The method for preparing a porous liquid mixing matrix membrane according to claim 1, characterized in that, In step S20, the oil bath heating conditions are 50~80℃, and the oil bath heating and stirring time is 8~16 hours.

5. The method for preparing a porous liquid mixing matrix membrane according to claim 1, characterized in that, In step S20, the vacuum pressure of the room temperature vacuum treatment is between 0.01 and 0.02 MPa, and the evacuation time is between 20 and 24 hours.

6. The application of the mixed matrix membrane obtained by the method for preparing porous liquid mixed matrix membrane according to claim 1, characterized in that, The mixed matrix membrane is required for separating mixed gases containing carbon dioxide. The transmembrane pressure difference of the mixed matrix membrane is required to be 0.1~0.5 MPa, and the operating temperature is 30~60℃.

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