Nanofluid mixed matrix membrane as well as preparation method and application thereof

Abstract

The invention discloses a nanofluid mixed matrix membrane as well as a preparation method and application thereof, and belongs to the field of gas separation. The nanofluid mixed matrix membrane comprises a polymer matrix and a nanofluid filler, the nanofluid filler is of a three-dimensional layered structure, a core layer is a porous material layer, a secondary outer layer is a coupling agent connecting layer, and an outermost layer is an organic matter coronal layer containing a CO2-philic group. The coronal layer improves the compatibility of the porous material and the polymer matrix and increases the CO2 affinity of the mixed matrix membrane, not only increases the diffusivity of the mixed matrix membrane, but also increases the CO2 solubility, and due to the unique connection mode between the porous core and the coronal layer, the thermal stability of the porous core and the coronal layer is also enhanced. Therefore, the prepared novel efficient mixed matrix membrane has good gas separation performance and thermal stability and is especially suitable for CO2 separation, and CO2 / H2 of the product breaks through the Robeson upper limit in 2008.

Description

TECHNICAL FIELD

[0001] The application relates to a nanofluid mixed matrix membrane and a preparation method and application thereof, and belongs to the technical field of gas separation membranes. BACKGROUND

[0002] At present, methods for CO2 capture include absorption, adsorption, low-pressure separation and membrane separation.

[0003] Membrane separation is concerned due to the advantages of easy amplification, low energy consumption, low investment, simple operation, high environmental friendliness, high space utilization and low operation environment requirement. The mixed matrix membrane is filled with inorganic fillers as a dispersed phase in a polymer as a continuous phase matrix, which can effectively combine the material properties of inorganic fillers and organic matrix, and provides an effective strategy for breaking through the 'Trade-off' limit of the permeability and selectivity of the polymer. The mechanical properties, chemical and thermal stability and plastic resistance of the mixed matrix membrane are improved compared with the pure polymer membrane, and the advantages of the polymer matrix and the inorganic filler can be fully utilized. Considering that the porous material has the characteristics of good stability, large specific surface area, large porosity and strong CO2 adsorption, it is the best choice for the mixed matrix membrane. However, the agglomeration of inorganic fillers, the poor compatibility of the polymer matrix and the inorganic fillers and the interface defects formed thereby are problems to be solved at present.

[0004] CO2 is an acidic gas with a unique dipole-quadrupole moment structure, so the organic matter rich in amino, hydroxyl and ether bond groups has strong CO2 affinity. These organic matters can customize the physical and chemical microenvironment in the blended membrane due to their own structure, so as to realize effective CO2 separation, and are excellent materials for separating CO2. However, due to the poor mechanical properties and thermal stability, the application field is limited to a certain extent. SUMMARY

[0005] For the problems of filler agglomeration and interface defects in the mixed matrix membrane, the application conceives a structure: a porous material as the core, a coupling agent as the connecting layer and an organic matter as the crown layer to form a new type of nanofluid. In this way, the compatibility problem of the porous filler can be solved, and the problems of poor mechanical properties and thermal stability of the mixed membrane with the organic matter as the dopant can be solved, so that the effect of 1+1>2 is achieved. Then, the new type of mixed matrix membrane is prepared by taking the nanofluid as the filler and the polymer matrix. Meanwhile, different types of nanofluids and mixed matrix membranes can be prepared by adjusting different crown layers, and the operability is very strong.

[0006] The application aims to solve the problems of poor compatibility of porous materials in mixed matrix membranes and poor mechanical properties and thermal stability of organic fillers. The method for nano-fluidization of porous materials provided by the application solves the problems of compatibility of porous materials and poor mechanical properties and thermal stability of organic materials in the crown layer. The nano-fluid mixed matrix membrane prepared on this basis has very high CO2 permeability and selectivity and can be used in the field of CO2 / N2 and CO2 / H2 separation involving CO2 separation. In order to achieve the technical effects described in the application, the application also provides a synthesis method of a multifunctional group two-dimensional MOF.

[0007] In one aspect of the application, a nano-fluid mixed matrix membrane is provided, which is a nano-fluid mixed matrix membrane for CO2 / N2 and CO2 / H2 separation involving CO2 separation,

[0008] The nano-fluid mixed matrix membrane comprises a polymer matrix and a nano-fluid filler.

[0009] The nano-fluid filler has a three-dimensional layered structure, wherein the core layer is a porous material layer, the secondary outer layer is a coupling agent connecting layer, and the outermost layer is a crown layer of organic matter containing CO2-philic groups.

[0010] In the application, the nano-fluid is composed of three parts: a porous material core, a coupling agent connecting layer, and a crown layer of organic matter containing CO2-philic groups. By grafting the crown layer of organic matter on the outer layer of the porous material, the compatibility problem between the porous material and the polymer is solved. The crown layer of organic matter solves the problems of poor mechanical properties and thermal stability by connecting with the porous material. The coupling agent achieves the effect of complementing the porous core and the crown layer of organic matter. The polymer matrix and the nano-fluid filler are prepared into a new type of mixed matrix membrane, which solves the compatibility problem between the polymer matrix and the filler and introduces CO2-philic groups, thereby greatly improving the CO2 permeability without reducing the selectivity. Therefore, the application is very suitable for CO2 separation.

[0011] Optionally, the porous material in the porous material layer is selected from at least one of metal organic framework materials, covalent organic framework materials, and hydrogen-bonded organic framework materials.

[0012] Optionally, the metal organic framework material (MOF) includes but is not limited to at least one of UIO-66, UIO-66-OH, UIO-66-(OH)2, MIL-101, MIL-101-OH, MIL-101-(OH)2, ZIF-8, ZIF-67, UIO-67, MOF-74, and MOF-808.

[0013] Optionally, the covalent organic framework (COF) includes, but is not limited to, at least one of COF-1, COF-2, COF-300, COF-5, CTF-1, COF-42, PI-COF-3.

[0014] Optionally, the hydrogen-bonded organic framework (HOF) includes, but is not limited to, at least one of HOF-100, HOF-101, HOF-102, TCF-1, TCF-2, TCF-3.

[0015] Optionally, in the nanofluid filler, the mass percentage of the porous material is 1-60wt%.

[0016] Optionally, in the nanofluid filler, the mass percentage of the porous material is independently selected from any value or a range value between any two of 1wt%, 2.8wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%.

[0017] Optionally, the coupling agent in the coupling agent connecting layer includes, but is not limited to, at least one of a silane coupling agent, an aluminate coupling agent, and a powder coupling agent.

[0018] Optionally, the CO2-philic group-containing organic matter in the CO2-philic group-containing organic matter crown layer is selected from organic matter containing at least one of amino, hydroxyl, ether, ester, carboxyl, carbonyl, and nitrile groups. The solubility and diffusivity of the mixed matrix membrane to the permeation component can be simultaneously improved, the gas permeation performance of the mixed matrix membrane can be effectively improved, and the compatibility of the porous material and the polymer matrix can be improved.

[0019] Optionally, the CO2-philic group-containing organic matter includes, but is not limited to, at least one of polyether amine, polyethylene glycol, polyethylene oxide, polylactic acid, polymethacrylate, polyvinyl formate, and polyurethane.

[0020] Optionally, the porous material layer and the coupling agent connecting layer are connected by at least one of a covalent bond, an ionic bond, intermolecular forces, and a hydrogen bond.

[0021] The coupling agent connecting layer and the CO2-philic group-containing organic matter crown layer are connected by at least one of a covalent bond, an ionic bond, intermolecular forces, and a hydrogen bond.

[0022] Optionally, the polymer matrix is a glassy polymer and / or a rubbery polymer.

[0023] Optionally, the polymer matrix includes, but is not limited to, at least one of polyether block amide, polyetherimide, polyimide, polyether-b-amide, and polyurethane.

[0024] Optionally, the nanofluid hybrid matrix film has a nanofluid filler mass percentage of 1-80 wt%.

[0025] Optionally, the nanofluid hybrid matrix film has a nanofluid filler mass percentage independently selected from any value of 1 wt%, 10 wt%, 15 wt%, 30 wt%, 50 wt%, 80 wt% or a range value between any two of the above values.

[0026] In another aspect of the present application, a preparation method of the nanofluid hybrid matrix film is provided, and the preparation method comprises:

[0027] The polymer matrix and the nanofluid filler are dissolved or dispersed in a solvent, ultrasonic stirring is performed to obtain a mixed solution, the mixed solution is degassed, and then a film is formed by a blade coating method or a flow casting method, and vacuum treatment is performed to obtain the nanofluid hybrid matrix film.

[0028] As a specific embodiment, the preparation method of the nanofluid hybrid matrix film comprises: the polymer matrix and the filler are respectively dissolved or dispersed in a solvent in a proportion, after dissolution or dispersion, mixing, ultrasonic stirring and stirring, a mixed matrix film solution is obtained, the solution is degassed, a film is formed by a blade coating method or a flow casting method, and residual solvent is removed by vacuum to obtain the hybrid matrix film.

[0029] Optionally, the solvent is at least one selected from a mixture of ethanol and water, a mixture of propanol and butanol, N,N-dimethylformamide, N,N-dimethylacetamide and N-methylpyrrolidone.

[0030] In the mixed solution, the total mass concentration of the polymer matrix and the nanofluid filler is 2-60 wt%.

[0031] Optionally, the preparation method of the nanofluid filler comprises:

[0032] (1) The porous material is uniformly dispersed by a water ball milling method to obtain a mixture;

[0033] (2) A solution I containing a coupling agent is mixed with the mixture to obtain a mixed solution, and in the mixed solution, the coupling agent and the porous material are connected by at least one of a covalent bond, an ionic bond, intermolecular forces and hydrogen bonds;

[0034] (3) A solution II containing the organic matter containing a CO2-philic group is mixed with the mixed solution obtained in step (2) to react, so that the coupling agent and the organic matter containing the CO2-philic group are connected by at least one of a covalent bond, an ionic bond, intermolecular forces and hydrogen bonds, and then dried to obtain the nanofluid filler without solvent.

[0035] The specific process for preparing the nanofluid is as follows: specifically including three steps: 1. coupling agent hydrolysis; 2. coupling agent and porous core branch connection; 3. coupling agent and crown layer organic matter connection.

[0036] Taking the MOF as the porous material core and the polyether amine as the crown layer to synthesize the nanofluid as an example, but not limited to this:

[0037] Under weak acid conditions, the coupling agent is hydrolyzed and reacts with the hydroxyl group on the MOF to be connected by covalent bond, and then the coupling agent is subjected to ring-opening reaction with the polyether amine under weak alkali conditions, so that the nanofluid is formed. As follows:

[0038]

[0039] In another aspect of the present application, the application of the above nanofluid mixed matrix membrane in the field of CO2 separation is provided.

[0040] The beneficial effects that can be produced by the present application include:

[0041] The present application provides a nanofluid mixed matrix membrane for CO2 / N2 and CO2 / H2 separation and other CO2 separation involving applications, which comprises a polymer matrix and a nanofluid filler, and preferably a polymer matrix and a nanofluid filler; the nanofluid is composed of three parts: a porous material core, a coupling agent connection layer, and a crown layer organic matter containing a CO2-philic group. In the mixed matrix membrane, the content of the nanofluid is 1-80 wt%, and the compatibility of the porous material with the polymer matrix can be improved and the CO2 affinity of the mixed matrix membrane can be increased by grafting the crown layer organic matter on the outer layer of the porous material, which increases the diffusion of the mixed matrix membrane and the CO2 solubility, solves the compatibility problem between the porous material and the polymer, and the thermal stability of the porous core and the crown layer is also enhanced due to the unique connection mode between the porous core and the crown layer provided by the present application, which solves the problems of poor mechanical properties and thermal stability, so that the porous core and the crown layer organic matter complement each other through the coupling agent. In this way, the new mixed matrix membrane prepared by the polymer matrix and the nanofluid filler solves the compatibility problem between the polymer matrix and the filler, and introduces the CO2-philic group, so that the CO2 permeability is greatly improved without reducing the selectivity, and therefore the present application is very suitable for CO2 separation. And the CO2 / H2 of the product breaks through the 2008 Robeson upper limit. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 CO2 / H2 Robeson upper limit graph in 2008;

[0043] Figure 2Figure 1 is a mixed matrix membrane electron micrograph, wherein a is a UIO-66-(OH)2 mixed matrix membrane obtained from Comparative Example 2, the scale is 10 μm, and b is a UIO-66-(OH)2 nanofluid mixed matrix membrane obtained from Example 2, the scale is 1 μm;

[0044] Figure 3 Figure 4 is a comparison chart of the gas permeability of the mixed matrix membranes in Example 7 and Comparative Example 3 of the present application;

[0045] Figure 4 Figure 3 is a comparison chart of the gas permeability of the mixed matrix membranes in Example 6 and Comparative Example 2 of the present application;

[0046] Figure 5 Figure 5 is a thermogravimetric analysis chart of MIL-101-OH-M2070, MIL-101-OH and M2070 in Example 1 and Example 7 of the present application (wherein the content of MIL-101-OH in MIL-101-OH-M2070 is 2.8 wt%).

[0047] Figure 6 Figure 6 is a mechanical property chart of 10 wt% Pebax1657 / M2070, 10 wt% Pebax1657 / 10 wt% UIO-66-(OH)2-M2070 and 10 wt% Pebax1657 / UIO-66-(OH)2 in Comparative Example 4, Example 6 and Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0048] The present application will be described in detail below with reference to the examples, but the present application is not limited to these examples.

[0049] In the examples of the present application, the raw materials were purchased through commercial channels unless otherwise specified.

[0050] The following will be further described by taking porous material MIL-101-OH and UIO-66-(OH)2 as the porous core, coupling agent KH560 as the coupling agent and polyetheramine as the crown layer as specific examples.

[0051] The analysis methods in the examples of the present application are as follows:

[0052] The gas permeability of MIL-101-OH-M2070 mixed matrix membranes and UIO-66-(OH)2-M2070 mixed matrix membranes was analyzed by using a permeation instrument.

[0053] The cross-section morphology of UIO-66-(OH)2 mixed matrix membranes and UIO-66-(OH)2-M2070 mixed matrix membranes was analyzed by using a field emission scanning electron microscope (JSM-7800F).

[0054] The mechanical properties of 10wt% Pebax1657 / M2070 blend membrane, 10wt% Pebax1657 / UIO-66-(OH)2-M2070 mixed matrix membrane and 10wt% UIO-66-(OH)2 mixed matrix membrane were analyzed by using a universal testing machine.

[0055] The thermal stability of MIL-101-OH, M2070, MIL-101-OH-M2070 was analyzed by using a thermal gravimetric analyzer (TGA) (STA449F5-Thermostar).

[0056] Example 1

[0057] Step one, MIL-101-OH preparation process:

[0058] Take 3.6g Cr(NO3)3·9H2O and dissolve it in 50.4ml water, then add 1.638g 2-hydroxyterephthalic acid (H2BDC-OH), stir the mixture at room temperature, then add it to the reaction kettle and put it into the constant temperature (130℃) air oven for reaction for 48h. After the reaction is completed and cooled to room temperature, centrifugal separation and washing are carried out, and then it is placed into the oven for drying to obtain MIL-101-OH.

[0059] Step two, synthesis of MIL-101-OH nanofluid:

[0060] Take 0.128g MIL-101-OH prepared in step one and put it into a ball mill tank with 1ml water, then take 0.472g silane coupling agent (KH560) and configure it into a 5wt% methanol solution, then mix the ball-milled MIL-101-OH with the KH560 methanol solution, and stir and heat at 70℃ to obtain a mixed solution. Take 4g polyetheramine (M2070) and configure it into a 10wt% methanol solution, then add the methanol solution containing polyetheramine into the above-mentioned mixed solution dropwise, stir at 80℃, and react for 24h, then dialyze the product with deionized water. Finally, the dialyzed product is rotary evaporated, and then dried at 60℃ until the mass no longer decreases.

[0061] Step three, preparation of MIL-101-OH nanofluid mixed matrix membrane:

[0062] The MIL-101-OH nanofluid prepared in step two is used.

[0063] Before preparation, Pebax1657 particles were dried in a vacuum oven at 60°C to remove adsorbed water and solvent. Pebax1657 and MIL-101-OH nanofluid were used as the matrix and filler of the mixed matrix membrane, respectively. The preparation process was as follows: Pebax1657 was dissolved in a mixture of ethanol and water (70 / 30 wt%) using a solution casting method. The mixture was heated and stirred at 80°C until completely dissolved. MIL-101-OH nanofluid was also dispersed in the ethanol and water (70 / 30 wt%) mixture and stirred. Then, the Pebax1657 solution and the MIL-101-OH nanofluid dispersion were mixed and sonicated. Finally, the mixture was stirred and poured into a polytetrafluoroethylene casting plate for evaporation to form a membrane. After removing the membrane from the mold, all membranes were dried in a vacuum oven at 60°C to remove residual solvent.

[0064] Example 2

[0065] Step 1: Preparation process of UIO-66-(OH)2:

[0066] 2.097 g of ZrCl4 was dissolved in 60 ml of dimethylformamide (DMF), followed by the addition of 1.782 g of 2,5-dihydroxyterephthalic acid (H2BDC-(OH)2) and 7 g of concentrated hydrochloric acid. The mixture was stirred at room temperature and then transferred to a reaction vessel, which was placed in a preheated oven at 130 °C for 48 h. After the reaction was completed and cooled to room temperature, the mixture was centrifuged, washed, and then dried in an oven to obtain MIL-101-(OH)2.

[0067] Step 2: Synthesis of UIO-66-(OH)2 nanofluids:

[0068] Weigh 0.128 g of the UIO-66-(OH)2 prepared in step one and place it in a ball mill jar with 1 ml of water for ball milling. Then weigh 0.473 g of silane coupling agent (KH560) and prepare a 5 wt% methanol solution. Mix the ball-milled UIO-66-(OH)2 with the KH560 methanol solution and stir and heat at 70 °C to obtain a mixture. Weigh 4 g of polyetheramine (M2070) and prepare a 10 wt% methanol solution. Add the methanol mixture containing polyetheramine dropwise to the above mixture and stir at 80 °C. After reacting for 24 h, dialyze the product with deionized water. Finally, rotary evaporate the dialyzed product and dry it at 60 °C until the mass no longer decreases.

[0069] Step 3: Preparation of UIO-66-(OH)2 nanofluidic mixed matrix film:

[0070] UIO-66-(OH)2 nanofluid was prepared using step two.

[0071] Before preparation, Pebax1657 particles were dried in a vacuum oven at 60°C to remove adsorbed water and solvent. Pebax1657 and UIO-66-(OH)2 nanofluid were used as the matrix and filler of the mixed matrix membrane, respectively. The preparation process was as follows: Pebax1657 was dissolved in a mixture of ethanol and water (70 / 30 wt%) using a solution casting method. The mixture was heated and stirred at 80°C until completely dissolved. UIO-66-(OH)2 nanofluid was also dispersed in the ethanol and water (70 / 30 wt%) mixture and stirred. Then, the Pebax1657 solution and the UIO-66-(OH)2 nanofluid dispersion were mixed and sonicated. Finally, the mixture was stirred and poured into a polytetrafluoroethylene casting plate for evaporation to form a membrane. After the membrane was removed from the mold, all membranes were dried in a vacuum oven at 60°C to remove residual solvent.

[0072] Example 3

[0073] Preparation of UIO-66-(OH)2 nanofluid hybrid matrix membrane.

[0074] The preparation process of the nanofluidic hybrid matrix membrane is the same as in Example 2.

[0075] A UIO-66-(OH)2 nanofluid hybrid matrix membrane with a mass fraction of 30 wt% and a MOF content of 10 wt% in the nanofluid, and polyetheramine M2070 as the organic material in the coronal layer. The permeation performance of the UIO-66-(OH)2 nanofluid hybrid matrix membrane under test conditions of 0.3 MPa and 35 °C is shown in Table 1.

[0076] Example 4

[0077] Preparation of UIO-66-(OH)2 nanofluid hybrid matrix membrane.

[0078] The preparation process of the nanofluidic hybrid matrix membrane is the same as in Example 2.

[0079] A UIO-66-(OH)2 nanofluid hybrid matrix membrane with a mass fraction of 30 wt% and a MOF content of 20 wt% in the nanofluid, and polyetheramine M2070 as the organic material in the coronal layer. The permeation performance of the UIO-66-(OH)2 nanofluid hybrid matrix membrane under test conditions of 0.3 MPa and 35 °C is shown in Table 1.

[0080] Example 5

[0081] The effect of pressure on the performance of UIO-66-(OH)2 nanofluid on hybrid matrix membranes.

[0082] The preparation method of the nanofluid is the same as in Example 2, and the preparation process of the nanofluid mixed matrix membrane is the same as in Example 2. In this example, UIO-66-(OH)2 nanofluid with a content of 20wt% was selected to prepare a UIO-66-(OH)2 nanofluid with a fluid content of 30wt%.

[0083] The test conditions were 0.1 MPa, 35℃, 0.3 MPa, 35℃, 0.5 MPa, 35℃, 0.7 MPa, and 35℃. The permeability of the UIO-66-(OH)₂ nanofluidic hybrid matrix membrane is shown in Table 1. The carbon dioxide permeability coefficients of the UIO-66-(OH)₂ nanofluidic hybrid matrix membrane were 205.86, 215.69, 209.02, and 214.55 Barrer. The CO2 / N2 selectivity was 46.22, 46.93, 46.36, and 49.01, respectively, and the CO2 / H2 selectivity was 9.46, 9.90, 9.58, and 10.05, respectively. All of these data are higher than those of pure membranes, indicating that the present invention has good permeation performance under different pressure conditions.

[0084] Example 6

[0085] Preparation of UIO-66-(OH)2 nanofluid hybrid matrix film

[0086] The preparation process of the nanofluidic hybrid matrix film is the same as in Example 2.

[0087] A UIO-66-(OH)2 nanofluid hybrid matrix membrane with a mass fraction of 15 wt% and a MOF content of 2.8 wt% in the nanofluid, and polyetheramine M2070 as the organic material in the coronal layer. The permeation performance of the UIO-66-(OH)2 nanofluid hybrid matrix membrane under test conditions of 0.3 MPa and 35 °C is shown in Table 1.

[0088] Example 7

[0089] Preparation of MIL-101-OH nanofluidic hybrid matrix film

[0090] The preparation process of the nanofluid hybrid matrix membrane was the same as in Example 1, using a 15 wt% MIL-101-OH nanofluid hybrid matrix membrane. The MOF content in the nanofluid was 2.8 wt%, and the organic material of the coronal layer was polyetheramine M2070. The permeation performance of the MIL-101-OH nanofluid hybrid matrix membrane under the test conditions of 0.3 MPa and 35 °C is shown in Table 1.

[0091] Example 8

[0092] Preparation of P84HT / MIL-101-OH-M2070 nanofluidic hybrid matrix film

[0093] The preparation process of the nanofluid is the same as in Example 1. The preparation process of the mixed matrix film is as follows:

[0094] Before preparation, P84HT particles were dried in a vacuum oven at 150°C to remove adsorbed water and solvent. P84HT and MIL-101-OH nanofluid were used as the matrix and filler of the mixed matrix membrane, respectively. The preparation process was as follows: 0.9 g of P84HT was placed in 17.1 g of N-methylpyrrolidone and stirred at 50°C until completely dissolved. 0.1 g of MIL-101-OH nanofluid was dispersed in 2 g of N-methylpyrrolidone and stirred. Then, the P84HT solution and the MIL-101-OH nanofluid dispersion were mixed and sonicated. The mixture was stirred and allowed to stand to remove bubbles. Finally, the mixture was poured onto a glass plate and formed into a membrane on a film coater at 50°C. After removing the membrane from the glass plate, it was dried in a vacuum oven at 150°C to remove residual solvent.

[0095] The permeation performance of the P84HT / MIL-101-OH-M2070 nanofluid hybrid matrix membrane under test conditions of 0.3MPa and 35℃ is shown in Table 1.

[0096] Table 1

[0097]

[0098] Examples 3-8 demonstrate that the hybrid matrix membrane prepared by this invention exhibits excellent gas permeation performance. Example 3, in particular, shows that this invention can operate stably under various pressures and demonstrates superior permeation performance.

[0099] Example 9

[0100] Preparation of UIO-66-OH-PLS nanofluids

[0101] Weigh 0.6 g of UIO-66-OH and place it in a ball mill jar with 1 ml of water for ball milling. Then weigh 0.5786 g of silane coupling agent (KH550) and prepare a 5 wt% methanol solution. Mix the ball-milled UIO-66-OH with the KH550 methanol solution and stir and heat at 70 °C to obtain a mixture. Weigh 4.8214 g of polyethylene glycol and prepare a 10 wt% methanol solution. Add the methanol mixture containing polyethylene glycol dropwise to the above mixture and stir at 80 °C. After reacting for 24 h, dialyze the product with deionized water. Finally, rotary evaporate the dialyzed product and dry it at 60 °C until the mass no longer decreases.

[0102] Example 10

[0103] Preparation of ZIF-67 nanofluids

[0104] 1 g of ZIF-67 was weighed and dispersed in 20 ml of toluene by stirring. Then, 50 mg of IDip was weighed and placed in the ZIF-67-toluene mixture and stirred for 24 h. After centrifugation and drying, the mixture was set aside for later use. ZIF-67-IDip was weighed, dispersed in toluene solution, and then added to 6 FDA-DAM to prepare a nanofluid with a ZIF-67 content of 10 wt%.

[0105] Example 11

[0106] Preparation of hollow silica nanofluids

[0107] Weigh 0.5786 g of silane coupling agent (KH560) and prepare a 5 wt% methanol solution. Then, mix 0.6 g of hollow silica with the KH550 methanol solution and stir and heat at 70 °C to obtain a mixed solution. Weigh 4.8214 g of M2070 and prepare a 10 wt% methanol solution. Add the methanol mixture containing M2070 dropwise to the above mixed solution and stir at 80 °C. After reacting for 24 h, dialyze the product with deionized water. Finally, rotary evaporate the dialyzed product and dry it at 60 °C until the mass no longer decreases.

[0108] Example 12

[0109] Synthesis of 10wt% MIL-101-OH-M2070 nanofluid

[0110] Weigh 0.6 g of MIL-101-OH prepared in step one of Example 1 and place it in a ball mill jar with 1 ml of water for ball milling. Then weigh 0.5786 g of silane coupling agent (KH560) and prepare a 5 wt% methanol solution. Mix the ball-milled MIL-101-OH with the KH560 methanol solution and stir and heat at 70°C to obtain a mixture. Weigh 4.8214 g of polyetheramine (M2070) and prepare a 10 wt% methanol solution. Add the methanol mixture containing M2070 dropwise to the above mixture and stir at 80°C. After reacting for 24 h, dialyze the product with deionized water. Finally, rotary evaporate the dialyzed product and dry it at 60°C until the mass no longer decreases.

[0111] Example 13

[0112] Synthesis of 20wt% MIL-101-OH-M2070 nanofluid

[0113] The steps are the same as in Example 12, except that the amounts of MIL-101-OH, KH560 and M2070 are 0.6g, 0.2571g and 2.142g, respectively.

[0114] Example 14

[0115] Synthesis of 50wt% MIL-101-OH-M2070 nanofluid

[0116] The steps are the same as in Example 12, except that the amounts of MIL-101-OH, KH560 and M2070 are 0.6g, 0.0643g and 0.5357g, respectively.

[0117] Example 15

[0118] Synthesis of 10wt% MIL-101-OH-M1000 nanofluid

[0119] The steps are the same as in Example 12, except that the amounts of MIL-101-OH, KH560, and M1000 are 0.6g, 0.5786g, and 4.8214g, respectively.

[0120] Example 16

[0121] Synthesis of 10wt% MIL-101-OH-M3085 nanofluid

[0122] The steps are the same as in Example 12, except that the amounts of MIL-101-OH, KH560 and M3085 are 0.6g, 0.5786g and 4.8214g, respectively.

[0123] Table 2

[0124] Nanofiller Nanofiller content Neck layer coupling agent Crown layer organic matter Example 9 UIO-66-OH 10 wt% KH550 PDMS Example 10 ZIF-67 10 wt% / 6FDA-DAM Example 11 Hollow silicon dioxide 10 wt% KH560 M2070 Example 12 MIL-101-OH 10 wt% KH560 M2070 Example 13 MIL-101-OH 20 wt% KH560 M2070 Example 14 MIL-101-OH 50 wt% KH560 M2070 Example 15 MIL-101-OH 10 wt% KH560 M1000 Example 16 MIL-101-OH 10 wt% KH560 M3085

[0125] As can be seen from Examples 9 to 16, this application has a wide range of applications and a solid foundation in the preparation of nanofluids.

[0126] Comparative Example 1

[0127] Preparation of MIL-101-OH mixed matrix membrane

[0128] Before preparation, Pebax1657 particles were dried in a vacuum oven at 60°C to remove adsorbed water and solvent. Pebax1657 and MIL-101-OH were used as the matrix and filler of the mixed matrix membrane, respectively. The preparation process was as follows: 0.51 g of Pebax1657 was dissolved in a mixture of ethanol and water (70 / 30 wt%) using a solution casting method. The mixture was heated and stirred at 80°C until completely dissolved. 0.09 g of MIL-101-OH was dispersed in the same mixture and stirred. Then, the Pebax1657 solution and MIL-101-OH dispersion were mixed and sonicated. Finally, the mixture was stirred and allowed to stand to degas, then poured into a polytetrafluoroethylene (PTFE) casting plate and evaporated to form a membrane. After removing the membrane from the mold, all membranes were dried in a vacuum oven at 60°C to remove residual solvent.

[0129] The permeation performance of the MIL-101-OH mixed matrix membrane with a mass fraction of 15 wt% under test conditions of 0.3 MPa and 35℃ is shown in Table 3.

[0130] Comparative Example 2

[0131] Preparation of UIO-66-(OH)2 mixed matrix membrane

[0132] Before preparation, Pebax1657 particles were dried in a vacuum oven at 60°C to remove adsorbed water and solvent. Pebax1657 and UIO-66-(OH)2 were used as the matrix and filler for the mixed matrix membrane, respectively. The preparation process was as follows: 0.51 g of Pebax1657 was dissolved in a mixture of ethanol and water (70 / 30 wt%) using a solution casting method. The mixture was heated and stirred at 80°C until completely dissolved. 0.09 g of UIO-66-(OH)2 was dispersed in the mixture of ethanol and water (70 / 30 wt%) and stirred. Then, the Pebax1657 solution and UIO-66-(OH)2 dispersion were mixed and sonicated. Finally, the mixture was stirred and poured into a polytetrafluoroethylene casting plate to evaporate and form a membrane. After the membrane was removed from the mold, all membranes were dried in a vacuum oven at 60°C to remove residual solvent.

[0133] The permeation performance of a 15 wt% UIO-66-(OH)2 mixed matrix membrane under test conditions of 0.3 MPa and 35℃ is shown in Table 3. Electron micrographs are shown below. Figure 2 a.

[0134] contrast Figure 2 Electron microscopy images of the UIO-66-(OH)2 membrane and the UIO-66-(OH)2 nanofluidic hybrid matrix membrane reveal severe filler agglomeration and interfacial defects in the MOF membrane, while the nanofluidic hybrid matrix membrane does not exhibit these issues. Therefore, the nanofluidic hybrid matrix membrane prepared in this application has significant technical and performance advantages over the MOF membrane.

[0135] Comparative Example 3

[0136] Preparation of Pebax1657 membrane

[0137] Before preparation, Pebax1657 particles were dried in a vacuum oven at 60°C to remove adsorbed water and solvent. The preparation process is as follows: 0.6 g of Pebax1657 was dissolved in a mixture of ethanol and water (70 / 30 wt%) using a solution casting method. The mixture was heated and stirred at 80°C until completely dissolved. The mixture was then poured into a polytetrafluoroethylene (PTFE) casting plate and evaporated to form a film. After the film was removed from the mold, it was dried in a vacuum oven at 60°C to remove residual solvent. The permeation performance under test conditions of 0.3 MPa and 35°C is shown in Table 3.

[0138] Comparative Example 4

[0139] Preparation of Pebax1657 / M2070 blend membrane

[0140] Before preparation, Pebax1657 particles were dried in a vacuum oven at 60°C to remove adsorbed water and solvent. Using Pebax1657 and M2070 as the matrix and filler, respectively, the preparation process was as follows: 0.51 g of Pebax1657 was dissolved in a mixture of ethanol and water (70 / 30 wt%) using a solution casting method. The mixture was heated and stirred at 80°C until completely dissolved. Then, 0.09 g of M2070 was added dropwise to the Pebax1657 film solution while stirring. Finally, the mixture was poured into a polytetrafluoroethylene (PTFE) casting plate and evaporated to form a film. After removing the film from the mold, all films were dried in a vacuum oven at 60°C to remove residual solvent.

[0141] The permeation performance of the Pebax1657 / M2070 blend membrane with a mass fraction of 15 wt% under test conditions of 0.3 MPa and 35℃ is shown in Table 3.

[0142] Comparative Example 5

[0143] Preparation of P84HT membrane

[0144] Before preparation, P84HT particles were dried in a vacuum oven at 150°C to remove adsorbed water and solvent. The preparation process is as follows: 1g of P84HT was placed in 19g of N-methylpyrrolidone and stirred at 50°C until completely dissolved to obtain a P84HT membrane solution. Finally, the P84HT membrane solution was poured onto a glass plate and formed into a film on a film coating machine at 50°C. After the film was formed, it was removed from the glass plate and dried in a vacuum oven at 150°C to remove residual solvent.

[0145] The permeation performance of the P84HT pure membrane under test conditions of 0.3 MPa and 35℃ is shown in Table 3.

[0146] Table 3

[0147]

[0148] By comparing Comparative Examples 1, 2, 3, 4, 5 with Examples 6, 7, 8, it can be seen that the present application has a significant advantage in gas permeation performance.

[0149] Test case

[0150] Figure 1 It can be seen that the CO2 / H2 separation performance of the nanofluidic hybrid matrix membrane in this application both exceed the upper limit of 2008robber, demonstrating excellent CO2 separation performance.

[0151] By comparison Figure 2 Electron microscopy images of UIO-66-(OH)2 and UIO-66-(OH)2 nanofluidic hybrid matrix films, UIO-66-(OH)2 hybrid matrix films ( Figure 2 Figure a) shows severe filler agglomeration and interface defects, while the UIO-66-(OH)2 nanofluidic mixed matrix membrane ( Figure 2 Figure b) shows that the above-mentioned situation did not occur. This proves that the hybrid matrix membrane filler prepared in this invention has excellent compatibility with the polymer matrix. Furthermore, from... Figure 5 The thermogravimetric analysis results show that the thermal stability of the MIL-101-OH nanofluid is stronger than that of MIL-101-OH and M2070, which fully demonstrates that the nanofluidization method for porous materials provided in this application can effectively improve the thermal stability of porous materials.

[0152] Figure 3 , Figure 4 The figures show the CO2 / N2 separation performance of the MIL-101-OH-M2070 mixed matrix membrane and the UIO-66-(OH)2-M2070 mixed matrix membrane with different contents, respectively. By comparison, it can be seen that the CO2 separation performance of both the MIL-101-OH-M2070 mixed matrix membrane and the UIO-66-(OH)2-M2070 mixed matrix membrane is significantly improved compared with the Pebax1657 pure membrane, proving that this application has superior CO2 separation performance.

[0153] By comparison Figure 6 The mechanical properties of the three mixed matrix membranes—M2070, UIO-66-(OH)2, and UIO-66-(OH)2-M2070—show that the nanofluid membrane prepared in this invention has significant advantages over the M2070 mixed matrix membrane in terms of Young's modulus, tensile strength, and elongation at break. Compared with the UIO-66-(OH)2 mixed matrix membrane, it also has advantages in tensile strength and elongation at break, combining the characteristics of high tensile strength and high toughness. This proves that the mixed matrix membrane prepared in this invention significantly improves the mechanical property problems faced by using MOF or polyetheramine as fillers alone.

[0154] 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 nanofluid hybrid matrix membrane, characterized in that, the nanofluid hybrid matrix membrane comprises a polymer matrix and a nanofluid filler; the nanofluid filler has a three-dimensional layered structure, wherein the core layer is a porous material layer, the secondary outer layer is a coupling agent connecting layer, and the outermost layer is a crown layer of organic matter containing CO2-philic groups.

2. The nanofluid hybrid matrix membrane according to claim 1, characterized in that, the porous material in the porous material layer is selected from at least one of metal organic framework material, covalent organic framework, and hydrogen-bonded organic framework; preferably, the metal organic framework material is selected from at least one of UIO-66, UIO66-OH, UIO-66-(OH)2, MIL-101, MIL-101-OH, MIL-101-(OH)2, ZIF-8, ZIF-67, UIO-67, MOF-74, MOF-808; preferably, the covalent organic framework is selected from at least one of COF-1, COF-2, COF-300, COF-5, CTF-1, COF-42, PI-COF-3; preferably, the hydrogen-bonded organic framework is selected from at least one of HOF-100, HOF-101, HOF-102, TCF-1, TCF-2, TCF-3; preferably, in the nanofluid filler, the mass fraction of the porous material is 1-60wt%.

3. The nanofluid hybrid matrix membrane according to claim 1, characterized in that, the coupling agent in the coupling agent connecting layer is selected from at least one of silane coupling agent, aluminate coupling agent, and powder coupling agent.

4. The nanofluid hybrid matrix membrane according to claim 1, characterized in that, the CO2-philic group-containing organic matter in the CO2-philic group-containing organic matter crown layer is selected from organic matter containing at least one of amino, hydroxyl, ether bond, ester group, carboxyl, carbonyl, and nitrile group; preferably, the CO2-philic group-containing organic matter is selected from at least one of polyether amine, polyethylene glycol, polyethylene oxide, polylactic acid, polymethacrylate, polyvinyl formate, and polyurethane.

5. The nanofluid hybrid matrix membrane according to claim 1, characterized in that, the porous material layer and the coupling agent connecting layer are connected by at least one of covalent bond, ionic bond, intermolecular force, and hydrogen bond; the coupling agent connecting layer and the CO2-philic group-containing organic matter crown layer are connected by at least one of covalent bond, ionic bond, intermolecular force, and hydrogen bond.

6. The nanofluid hybrid matrix membrane according to claim 1, characterized in that, the polymer matrix is a glassy polymer and / or a rubbery polymer; preferably, the polymer matrix is selected from at least one of polyether block amide, polyetherimide, polyimide, polyether-b-amide, and polyurethane; preferably, the nanofluid hybrid matrix membrane, the mass fraction of the nanofluid filler is 1-80wt%.

7. A preparation method of the nanofluid hybrid matrix membrane according to any one of claims 1-6, characterized in that, The polymer matrix and the nanofluid filler are dissolved or dispersed in a solvent, and a mixed solution is obtained by ultrasonic stirring, the mixed solution is degassed, and then a film is formed by a scraping method or a casting method, and the nanofluid mixed matrix film is obtained after vacuum treatment.

8. The preparation method according to claim 7, characterized in that, the solvent is at least one selected from the group consisting of an ethanol and water mixed solution, a propanol and butanol mixed solution, N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; the total mass concentration of the polymer matrix and the nanofluid filler in the mixed solution is 2-60 wt%.

9. The preparation method according to claim 7, characterized in that, the preparation method of the nanofluid filler comprises: (1) uniformly dispersing the porous material by a water ball milling method to obtain a mixture; (2) mixing a solution I containing a coupling agent with the mixture, and reacting to obtain a mixed solution, wherein the coupling agent and the porous material are connected by at least one of a covalent bond, an ionic bond, intermolecular force, and a hydrogen bond in the mixed solution; (3) mixing a solution II containing the CO2-philic organic matter with the mixed solution obtained in step (2), and reacting to connect the coupling agent and the CO2-philic organic matter by at least one of a covalent bond, an ionic bond, intermolecular force, and a hydrogen bond, and drying to obtain the nanofluid filler without solvent.

10. Application of the nanofluid mixed matrix film according to any one of claims 1-6 in the field of CO2 separation.

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