Gel mixed matrix membrane, its preparation method and application

Abstract

The application provides a gel mixed matrix membrane for gas separation and a preparation method and application thereof, and belongs to the field of gas membrane separation. The gel mixed matrix membrane comprises a mixed matrix and a gel agent; the mixed matrix comprises a polymer matrix and a filler; the gel agent is selected from lipids, alcohols, ethers or amines; and the molecular weight of the gel agent is 120-500. The gel mixed matrix membrane is prepared by adding a gel agent to the mixed matrix to make it gel. The gel mixed matrix membrane provided by the application has high gas permeation coefficient, high stability and pressure resistance, and is suitable for CO2 gas separation.

Description

Technical Field

[0001] This invention belongs to the field of gas membrane separation, specifically relating to a gel-mixed matrix membrane, its preparation method, and its application in CO2 separation. Background Technology

[0002] With global economic growth and the development of the chemical industry, energy conservation and emission reduction are two crucial issues for the sustainable development of the Earth. CO2 is not only a major contributor to the greenhouse effect but also an important potential carbon source, which can be converted into resources such as CO and HCO2H through photochemical and electrochemical technologies. Therefore, carbon capture, utilization, and storage (CCSU) is of great significance for solving environmental and energy problems.

[0003] Membrane technology, as an effective CO2 separation technology, has advantages such as low energy consumption, low cost, and environmental friendliness, and has promising application prospects. Currently, pure polymer membranes still dominate gas separation membranes. However, there is a "trade-off" relationship between gas permeability and selectivity in pure polymer membranes; that is, membranes with high permeability have low selectivity, and vice versa. Mixed matrix membranes (MMMs) add fillers to polymers, combining the advantages of both polymers and fillers to improve gas separation performance. This provides an effective method to overcome the "trade-off" barrier of pure polymers. However, the fillers in mixed matrix membranes are prone to aggregation, resulting in irregular voids within the membrane and causing non-selective gas permeation.

[0004] Gel-based hybrid membranes are gel-like membranes created by adding small liquid molecules to a polymer. Compared to pure polymer membranes and hybrid matrix membranes, gel membranes exhibit extremely high gas permeability. However, gel membranes have poor stability; their permeability and selectivity decrease significantly with increasing testing time. Furthermore, gel membranes have poor pressure resistance; as pressure increases, the gel membrane tends to become denser, increasing gas permeation resistance and reducing permeability. Summary of the Invention

[0005] Based on the above technical problems, the purpose of this invention is to provide a novel gel-mixed matrix membrane (g-MMMs) for gas separation, its preparation method, and its applications. Gel-mixed matrix membranes are prepared by adding a gelling agent to a mixed matrix to induce gelation, resulting in a gel-like membrane. The addition of the gelling agent promotes the dispersion of the packing material and alleviates the problem of packing material agglomeration. The gel-mixed matrix membrane of this invention combines the extremely high gas permeability coefficient of gel membranes with the high stability and pressure resistance of mixed matrix membranes, exhibiting excellent separation performance in CO2 separation.

[0006] According to one aspect of the present invention, a gel-mixed matrix membrane is provided, the gel-mixed matrix membrane comprising a mixed matrix and a gelling agent; the mixed matrix comprising a polymer matrix and a filler;

[0007] The gelling agent is selected from lipid liquid organic compounds, alcohol liquid organic compounds, ether liquid organic compounds, or amine liquid organic compounds; the molecular weight of the gelling agent is 120-500.

[0008] When the molecular weight of the gelling agent is below 120, the prepared gel-mixed matrix membrane has poor mechanical properties; when the molecular weight is above 500, the prepared gel-mixed matrix membrane has a low CO2 permeability coefficient. The gelling agent is preferably a liquid organic compound such as a lipid, alcohol, ether, or amine. Ester, alcohol, and ether groups have a high affinity for CO2, which can improve CO2 permeability and facilitate the separation of CO2 from nonpolar molecular gases.

[0009] Optionally, the lipid liquid organic compound is selected from at least one of amyl acetate, butyl acrylate, ethyl acetoacetate, ethyl phenoxyacetate, pentaerythritol triacrylate, acetylated tributyl citrate, triethyl citrate, and tributyl citrate.

[0010] Optionally, the ether-based liquid organic compound is selected from at least one of ethyl phenyl ether and ethylene glycol phenyl ether.

[0011] Optionally, the alcoholic liquid organic compound is selected from at least one of ethylene glycol phenyl ether acetate, 2-phenoxypropanol, and 1-phenoxy-2-propanol.

[0012] Optionally, the amine liquid organic compound is selected from at least one of dimethylthiotoluene diamine and isophorone diamine.

[0013] Optionally, the content of the gelling agent is 1 wt% to 80 wt% of the mass of the gel-mixed matrix membrane.

[0014] Optionally, the content of the gelling agent is selected from the upper limit of the mass of the gel-mixed matrix membrane, which is 75wt%, 70wt%, 65wt%, 60wt%, 55wt%, 50wt%, 40wt%, 30wt%, or any value between any two of the above points; and the lower limit is selected from 2wt%, 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, or any value between any two of the above points.

[0015] Optionally, the filler content is 3 wt% to 35 wt% of the mixed matrix.

[0016] Optionally, the content of the filler is selected from the upper limit of 33wt%, 30wt%, 25wt%, 22wt%, 20wt%, 15wt%, 12wt%, or any value between any two of the above points; and the lower limit is selected from 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, or any value between any two of the above points.

[0017] When the filler content is less than 3 wt%, the filler does not significantly improve the pressure resistance and stability of the gel-mixed matrix membrane; when the filler content is higher than 35 wt%, the mechanical properties of the gel-mixed matrix membrane are greatly reduced, which is not conducive to industrial gas separation applications.

[0018] Optionally, the filler is a porous filler, preferably at least one of carbon nanotubes, carbon molecular sieves, hollow silica, hydrotalcite, metal-organic frameworks, or covalent organic frameworks.

[0019] Porous fillers can promote gas diffusion within the membrane, increase the gas permeability coefficient, and have good structural stability, effectively enhancing the pressure resistance and stability of gel-mixed matrix membranes.

[0020] Optionally, the polymer matrix is ​​selected from polyether, polyester, and polyamide block polymers.

[0021] Optionally, the polymer matrix is ​​selected from at least one of polyether ester, polyimide, polyether block polyimide, and polyether urethane.

[0022] According to one aspect of the present invention, a method for preparing the above-mentioned gel-mixed matrix membrane is provided, wherein a homogeneous casting mixture containing polymer, filler and gelling agent is defoamed, formed into a film, and subjected to vacuum treatment to remove residual solvent to obtain the gel-mixed matrix membrane.

[0023] The film can be formed by scraping or casting.

[0024] Optionally, after mixing the polymer-containing solution a with the filler-containing mixture b, a gelling agent is added to obtain the casting film mixture solution.

[0025] The polymer, filler, and gelling agent can be directly mixed in the solvent or added separately. Preferably, the polymer and filler are dissolved and dispersed separately in the solvent. After the polymer is completely dissolved and the filler is fully dispersed, the filler solution is added to the polymer solution. After the two are fully mixed, the gelling agent is added. Then the temperature is lowered and the mixture is stirred to fully mix the mixed matrix and the gelling agent to obtain the casting film mixed solution.

[0026] When mixing to obtain the casting film mixture solution, ultrasonic-assisted mixing can be used.

[0027] Optionally, the polymer has a melting temperature of 30–150°C;

[0028] The stirring time is 4 to 28 hours; the stirring temperature is 20 to 80°C.

[0029] Optionally, the total mass concentration of the polymer, filler, and gelling agent in the casting mixture is 2 wt% to 30 wt%.

[0030] Optionally, the solvent of the casting mixture is selected from at least one of aqueous ethanol, dichloromethane, trichloroethane, ethanol, chloroform, tetrahydrofuran, diethyl ether, and acetone.

[0031] Optionally, the vacuum treatment temperature is 15–50°C, and the treatment time is 36–144 hours.

[0032] According to one aspect of the present invention, the above-described gel-mixed matrix membrane and the application of the gel-mixed matrix membrane prepared by the above-described preparation method in gas separation are provided.

[0033] Optionally, the gel-mixed matrix membrane is used in the separation of gas mixtures containing CO2.

[0034] Optionally, the gas mixture comprises a nonpolar gas.

[0035] Preferably, the nonpolar gas contains at least one of N2, CH4, and H2.

[0036] In this application, the gas mixture comes into contact with one side of the gel-mixed matrix membrane, thereby causing CO2 to permeate the gel-mixed matrix membrane to achieve a gas separation effect.

[0037] The beneficial effects that this invention can produce include:

[0038] (1) The gel polymer matrix membrane provided by the present invention comprises a mixed matrix and a gelling agent, wherein the mixed matrix comprises a polymer and a filler. The filler in the gel mixed matrix membrane provided by the present invention has good dispersibility, high CO2 gas permeability, and high stability and pressure resistance.

[0039] (2) The film-making method provided by the present invention is simple and easy to implement, has a wide range of applications, and has good prospects for practical application. Attached Figure Description

[0040] Figure 1 This is an electron microscope image of the gel-mixed matrix membrane prepared in Example 5.

[0041] Figure 2 The image shows an electron microscope image of the hybrid matrix film prepared in Comparative Example 2.

[0042] Figure 3The relationship between CO2 permeability and time is shown for the gel-mixed matrix membrane prepared in Example 7 and the gel membrane prepared in Comparative Example 5.

[0043] Figure 4 The relationship between CO2 permeation performance and pressure is shown for the gel-mixed matrix membranes prepared in Examples 5-7 and the gel membranes prepared in Comparative Examples 3-5.

[0044] Figure 5 The CO2 permeability and gas separation selectivity of Examples 5-8 and Comparative Examples 1-2 are presented.

[0045] Figure 6 For comparison of the mechanical properties of Comparative Example 7 and Examples 1-4. Detailed Implementation

[0046] The present invention will be further described in detail below with reference to specific embodiments, but the present invention is not limited to the specific embodiments.

[0047] The gas permeation coefficient of the gel-mixed matrix membrane prepared in this invention was obtained by constant volume pressure variation (CPP). The membrane was fixed between a circular stainless steel module and two sealed O-ring silicone rubber rings. During the test, the upstream flow rate remained constant, the gas mixture was preheated in the upstream volume, and permeated through the membrane into the downstream volume under the driving force of the pressure difference. The rate of change of downstream pressure was measured using a sensitive pressure sensor.

[0048] The formula for calculating the gas permeability coefficient is as follows:

[0049]

[0050] in,

[0051] The permeability coefficient P is measured in Barrers, where 1 Barrer = 10⁻⁶. -10 cm 3 (STP)·cm / (cm 2 ·s·cmHg);

[0052] V is the volume of the gas on the permeate side, in cm³. 3 ;

[0053] A is the effective area of ​​the membrane, in cm² 2 ;

[0054] L is the thickness of the membrane, in cm;

[0055] T is the temperature during permeation, in K;

[0056] Δp is the absolute pressure difference between the feed side and the permeation side, in cmHg;

[0057] dp / dt represents the rate of increase in pressure on the permeable side, in mmHg / s.

[0058] Gas selectivity α i / j Calculated using the following formula:

[0059]

[0060] Among them, P i and P j Let be the permeability coefficients of gas i and gas j, respectively.

[0061] The EM400 described in this example was purchased from DSM (China) Co., Ltd.

[0062] Example 1

[0063] 2.7 g of EM400 was dissolved in 60 g of dichloromethane and stirred at 50 °C for 5 h. 0.3 g of carbon nanotube (CNT) filler was added to 40 g of dichloromethane and sonicated for 4 h. The two solutions were then mixed, and 3 g of methyl benzoate (MB, molecular weight 136 g / mol) was added. The mixture was stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate. The solvent was evaporated at room temperature. After film formation, the film was removed and placed in a vacuum oven at 30 °C for 96 h to remove residual solvent, yielding EM400-CNT composite material. 9-1 A gel-mixed matrix membrane, consisting of EM400 and CNT in a 9:1 mass ratio, and methyl benzoate as a gelling agent comprising 50 wt% of the gel-mixed matrix membrane, is named (EM400-CNT). 9-1 ) / MB 50wt％ Gel-mixed matrix membrane.

[0064]

[0065] EM400 is a polyether-ester block polymer composed of 40% polybutylene terephthalate (PBT) hard segments and 60% polytetrahydrofuran soft segments, as shown in Formula I. The EM400 polymer chain is rich in ester and ether groups, exhibiting good affinity for CO2 and facilitating CO2 penetration.

[0066] Examples 2-4

[0067] 2.7g of EM400 was dissolved in 60g of dichloromethane and stirred at 50℃ for 5h. 0.3g of carbon nanotube (CNT) filler was added to 40g of dichloromethane and ultrasonically vibrated for 4h. The two solutions were mixed, and 3g of gelling agent was added. The mixture was stirred at 30℃ for 4h until homogeneous. After standing for 10min to remove bubbles, the mixture was cast onto a PTFE plate. The solvent was evaporated at room temperature. After film formation, the film was removed and placed in a vacuum oven at 30℃ for 96h to remove residual solvent, resulting in a gel-mixed matrix film with a gelling agent content of 50wt%.

[0068] The gelling agent used in Example 2 was ethyl phenylacetate (BA).

[0069] The gelling agent used in Example 3 was triethyl citrate (TEC).

[0070] The gelling agent used in Example 3 was tributyl acetyl citrate (TOA).

[0071] The specific usage of the gel is shown in Table 1.

[0072] Table 1.

[0073]

[0074] Test Example 1

[0075] Table 2 shows the CO2 permeability and selectivity of the gel-mixed matrix membranes in Examples 1-4 under 0.3 MPa and 35°C conditions for CO2 / N2, CO2 / CH4, and CO2 / H2 gas mixtures.

[0076] Table 2.

[0077]

[0078] As can be seen from the gas separation performance of Examples 1-4, the CO2 permeability coefficient of the prepared gel-mixed matrix membrane decreases with the increase of the molecular weight of the gelling agent. The larger molecular weight of the gelling agent increases the steric hindrance, slows down the movement of the polymer matrix molecular chains, and hinders the permeation of gas.

[0079] Example 5

[0080] 2.7 g of EM400 was dissolved in 60 g of dichloromethane and stirred at 50 °C for 5 h. 0.3 g of carbon nanotube (CNT) filler was added to 40 g of dichloromethane and ultrasonically vibrated for 4 h. The two solutions were then mixed, and 0.75 g of triethyl citrate (TEC, molecular weight 276 g / mol) was added. The mixture was stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate. The solvent was evaporated at room temperature. After film formation, the film was removed and placed in a vacuum oven at 30 °C for 96 h to remove residual solvent. This yielded a gel-mixed matrix film with EM400-CNT (EM400 to CNT mass ratio of 9:1) as the mixed matrix and triethyl citrate as the gelling agent at a content of 20 wt% of the gel-mixed matrix film. This film was named (EM400-CNT). 9-1 ) / TEC 20wt％ Gel-mixed matrix membrane.

[0081] Examples 6-8

[0082] 2.7 g of EM400 was dissolved in 60 g of dichloromethane and stirred at 50 °C for 5 h. 0.3 g of carbon nanotube (CNT) filler was added to 40 g of dichloromethane and ultrasonically vibrated for 4 h. The two solutions were mixed and different masses of triethyl citrate (TEC, molecular weight 276 g / mol) were added. The mixture was stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate and the solvent was evaporated at room temperature. After film formation, the film was removed and placed in a vacuum oven at 30 °C for 96 h to remove residual solvent, thus preparing gel-mixed matrix films with different TEC contents.

[0083] The mass of triethyl citrate described in Example 6 is 2g.

[0084] The mass of triethyl citrate described in Example 7 was 4.5 g.

[0085] The mass of triethyl citrate described in Example 8 was 12g.

[0086] The specific usage of EM400, CNT, and TEC is shown in Table 3.

[0087] Table 3.

[0088]

[0089] Test Example 2

[0090] Table 4 shows the CO2 permeability and selectivity of the gel-mixed matrix membranes in Examples 5-8 under conditions of 0.3 MPa and 35°C, and when the gas mixture is CO2 / N2, CO2 / CH4, or CO2 / H2.

[0091] Table 4.

[0092]

[0093] Figure 1 The (EM400-CNT) prepared in Example 5 9-1 ) / TEC 20wt％ Electron micrograph of a gel-mixed matrix membrane, by Figure 1 It can be seen that the carbon nanotube filler in the gel-mixed matrix membrane has good dispersibility and no voids appear, indicating that the addition of triethyl citrate (TEC) can act as a dispersant to promote the dispersibility of the filler.

[0094] Example 9

[0095] 2.7 g of EM400 was dissolved in 60 g of dichloromethane and stirred at 50 °C for 5 h. 0.3 g of ZIF-8 metal-organic framework filler was added to 40 g of dichloromethane and sonicated for 4 h. The two solutions were then mixed, and 3 g of triethyl citrate (TEC, molecular weight 276 g / mol) was added. The mixture was stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate. The solvent was evaporated at room temperature. After film formation, the plate was removed and placed in a vacuum oven at 30 °C for 96 h to remove residual solvent, yielding EM400-ZIF-8. 9-1 A gel-mixed matrix membrane, consisting of EM400 and ZIF-8 in a 9:1 mass ratio, and triethyl citrate as a gelling agent comprising 50 wt% of the gel-mixed matrix membrane, is named (EM400-ZIF-8). 9-1 ) / TEC 50wt％ Gel-mixed matrix membrane.

[0096] Test Example 3

[0097] Example 9 (EM400-ZIF-8) 9-1 ) / TEC 50wt％ The CO2 permeation performance of the membrane under 0.3 MPa and 35 °C and the selectivity performance of the gas mixtures CO2 / N2, CO2 / CH4, and CO2 / H2 are shown in Table 5.

[0098] Table 5.

[0099]

[0100] The (EM400-ZIF-8) prepared in Example 9 9-1 ) / TEC 50wt％ The gel-mixed matrix membrane and the (EM400-CNT) prepared in Example 3 9-1 ) / TEC 50wt％ The gas separation performance of the gel-mixed matrix membrane shows that gel-mixed matrix membranes with different packing materials exhibit varying CO2 gas separation performance. The CO2 permeability coefficient of the gel-mixed matrix membrane prepared in Example 9 is slightly lower than that of the gel-mixed matrix membrane prepared in Example 3. This is because the ZIF-8 packing material used in Example 9 has a small pore size, which reduces CO2 diffusion within the membrane. Simultaneously, the small pore size of ZIF-8 also significantly reduces the diffusion of N2 and CH4, which have larger kinetic diameters than CO2, within the membrane, thereby increasing the CO2 / N2 and CO2 / CH4 separation selectivity.

[0101] Comparative Example 1

[0102] 3g of EM400 was dissolved in 100g of dichloromethane solution and stirred at 50℃ for 5h. After stirring at 30℃ for 4h until homogeneous, the mixture was sonicated for 10min to remove bubbles and then cast onto a PTFE plate. The solvent was evaporated at room temperature. After film formation, the film was removed and placed in a 40℃ vacuum oven for 96h to remove residual solvent, thus obtaining a pure EM400 film.

[0103] Test Example 4

[0104] Table 6 shows the CO2 permeation performance of the pure EM400 membrane in Comparative Example 1 under conditions of 0.3 MPa and 35 °C, and the selectivity performance of the gas mixtures CO2 / N2, CO2 / CH4, and CO2 / H2.

[0105] Table 6.

[0106]

[0107] Comparative Example 2

[0108] 2.7 g of EM400 was dissolved in 60 g of dichloromethane and stirred at 50 °C for 5 h. 0.3 g of carbon nanotube (CNT) filler was added to 40 g of dichloromethane and ultrasonically vibrated for 4 h. The two solutions were then mixed and stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate. The solvent was evaporated at room temperature. After film formation, the film was removed and placed in a vacuum oven at 30 °C for 96 h to remove residual solvent, resulting in a mixed matrix film of EM400-CNT (EM400 to CNT mass ratio of 9:1), named EM400-CNT. 9-1 Hybrid matrix membrane.

[0109] Test Example 5

[0110] The CO2 permeation performance and selectivity of the mixed matrix membrane prepared in Comparative Example 2 under conditions of 0.3 MPa and 35 °C for gas mixtures of CO2 / N2, CO2 / CH4, and CO2 / H2 are shown in Table 7.

[0111] Table 7.

[0112]

[0113] Figure 2 EM400-CNT prepared for Comparative Example 2 9-1 The electron micrograph of the hybrid matrix membrane shows that the carbon nanotube filler exhibits aggregation, with irregular voids between the fillers. (Comparison) Figure 1 and Figure 2 It can be seen that, Figure 1The carbon nanotube filler in the gel-mixed matrix membrane exhibited good dispersion with no voids, indicating that the addition of triethyl citrate (TEC) can act as a dispersant to promote the dispersion of the filler.

[0114] Comparing the pure EM400 membrane prepared in Comparative Example 1 and the EM400-CNT prepared in Comparative Example 2 9-1 The gas separation performance of the mixed matrix membrane shows that the addition of porous carbon nanotubes (CNTs) can improve the CO2 permeability of the membrane, because the porous filler promotes the diffusion of gas within the membrane.

[0115] A comparison of the gas separation performance of the gel-mixed matrix membranes prepared in Examples 5-8 with that in Comparative Example 2 shows that the addition of triethyl citrate (TEC) significantly improves gas permeability. TEC exists in a free form in the gel-mixed matrix membrane, greatly enhancing gas diffusion and dissolution, thereby increasing the gas permeability coefficient. Furthermore, the permeability coefficient increases with increasing TEC content in the gel-mixed matrix membrane. The TEC molecule contains ester groups, which have a good affinity for CO2, promoting CO2 permeation and contributing to improved gas selectivity.

[0116] Figure 5 The figures show the CO2 permeation performance and gas separation selectivity of Examples 5-8 and Comparative Examples 1-2. As can be seen from the figures, the pure EM400 membrane of Comparative Example 1 and the EM400-CNT membrane of Comparative Example 2 are compared. 9-1 The addition of TEC to the gel-mixed matrix membranes in Examples 5-8 significantly improved CO2 permeability and CO2 / N2, CO2 / CH4, and CO2 / H2 selectivity. Furthermore, the CO2 permeability and selectivity of the gel-mixed matrix membranes increased with the increase of TEC content.

[0117] Comparative Example 3

[0118] 3.0 g of EM400 was dissolved in 100 g of dichloromethane and stirred at 50 °C for 5 h. After the polymer was completely dissolved, 0.75 g of triethyl citrate (TEC) was added, and the mixture was stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate. The solvent was evaporated at room temperature, and after film formation, the plate was removed and placed in a vacuum oven at 30 °C for 96 h to remove residual solvent, yielding an EM400 / TEC gel film with a TEC content of 20 wt%, named EM400 / TEC. 20wt％ Gel membrane.

[0119] Comparative Examples 4-6

[0120] 3.0 g of EM400 was dissolved in 100 g of dichloromethane and stirred at 50 °C for 5 h. After the polymer was completely dissolved, different masses of triethyl citrate (TEC) were added, and the mixture was stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate, and the solvent was evaporated at room temperature. After film formation, the plate was removed and placed in a vacuum oven at 30 °C for 96 h to remove residual solvent, thus preparing gel films with different TEC contents.

[0121] The specific usage of EM400 and TEC is shown in Table 8.

[0122] Table 8.

[0123] Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 TEC content in gel film 20 wt% 40 wt% 60 wt% 80 wt% EM 400 / g 3 3 3 3 TEC / g 0.75 2 4.5 12

[0124] Test Example 6

[0125] Table 9 shows the CO2 permeability of the gel membranes in Comparative Examples 3–6 under conditions of 0.3 MPa and 35 °C, and their selectivity for gas mixtures of CO2 / N2, CO2 / CH4, and CO2 / H2.

[0126] Table 9.

[0127]

[0128] Figure 3 The (EM400-CNT) prepared in Example 7 9-1 ) / TEC 60wt％ The gel-mixed matrix membrane and the EM400 / TEC prepared in Comparative Example 5 60wt％ The permeability of the gel membrane changes over time. The figure shows the change in permeability of the EM400 / TEC membrane prepared in Comparative Example 5. 60wt％ The gel membrane exhibited poor permeation stability, with its CO2 permeation performance decreasing sharply within the test period, from 1226 Barrer to 970 Barrer, a reduction of approximately 30%; while the (EM400-CNT) membrane in Example 7... 9-1 ) / TEC 60wt％ The gel-mixed matrix membrane maintained stable high CO2 permeability within 180 hours of the experiment, indicating that the permeability stability of the gel-mixed matrix membrane is better than that of the gel membrane.

[0129] Figure 4The figure shows the change in CO2 permeability of the gel-mixed matrix membranes prepared in Examples 5-7 and the gel membranes in Comparative Examples 3-5 as a function of pressure. As can be seen from the figure, the CO2 permeability coefficient of the gel membranes prepared in Comparative Examples 3 and 5 decreases with increasing pressure, while the CO2 permeability coefficient of the gel-mixed matrix membranes in Examples 5 and 6 increases with increasing pressure. When the pressure increases from 0.01 MPa to 0.9 MPa, the CO2 permeability coefficient of the gel membrane in Comparative Example 6 decreases by 36%, while the CO2 permeability coefficient of the gel-mixed matrix membrane in Example 7 decreases by only 20%, indicating that the pressure resistance of the gel-mixed matrix membrane is better than that of the gel membrane.

[0130] Comparative Example 7

[0131] 2.7 g of EM400 was dissolved in 60 g of dichloromethane and stirred at 50 °C for 5 h. 0.3 g of carbon nanotube (CNT) filler was added to 40 g of dichloromethane and sonicated for 4 h. The two solutions were then mixed, and 3 g of ethyl acrylate (EA, molecular weight 100 g / mol) was added. The mixture was stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate. The solvent was evaporated at room temperature. After film formation, the film was removed and placed in a 30 °C vacuum oven for 96 h to remove residual solvent, yielding EM400-CNT composite material. 9-1 A gel-mixed matrix membrane, consisting of EM400 and CNT in a 9:1 mass ratio, and ethyl acrylate as a gelling agent comprising 50 wt% of the gel-mixed matrix membrane, is named (EM400-CNT). 9-1 ) / EA 50wt％ Gel-mixed matrix membrane.

[0132] Figure 6 The mechanical properties of Comparative Example 7 and Examples 1-4 are compared. As shown in the figure, the elastic modulus and tensile strength of the gel-mixed matrix membrane increase with increasing molecular weight of the gelling agent. The elastic modulus and tensile strength of Comparative Example 7 are lower than those of Examples 1-4. This is because high molecular weight gelling agents facilitate physical cross-linking with polymer chains, enhancing the interaction forces between the components of the gel-mixed matrix membrane and thus improving its mechanical properties. Therefore, considering the mechanical properties of the gel-mixed matrix membrane, the molecular weight of the gelling agent should not be too low, preferably greater than 120 g / mol.

[0133] Comparative Example 8

[0134] 2.7 g of EM400 was dissolved in 60 g of dichloromethane and stirred at 50 °C for 5 h. 0.3 g of carbon nanotube (CNT) filler was added to 40 g of dichloromethane and sonicated for 4 h. The two solutions were then mixed, and 3 g of glyceryl trinonanoate (GT, molecular weight 544 g / mol) gelling agent was added. The mixture was stirred at 30 °C for 4 h until homogeneous. After standing for 10 min to remove bubbles, the mixture was cast onto a PTFE plate. The solvent was evaporated at room temperature, and after film formation, the plate was removed and placed in a vacuum oven at 30 °C for 96 h to remove residual solvent, thus preparing an EM400-CNT gelling agent with a content of 50 wt%. 9-1 ) / GT 50wt％ Gel-mixed matrix membrane.

[0135] Test Example 7

[0136] Table 10 shows the CO2 permeability of the gel-mixed matrix membrane in Comparative Example 8 under 0.3 MPa and 35 °C conditions, as well as its selectivity for CO2 / N2, CO2 / CH4, and CO2 / H2 gas mixtures.

[0137] Table 10.

[0138]

[0139] The gel-mixed matrix membrane prepared in Comparative Example 8 had a gelling agent, glyceryl trinonanoate, with a molecular weight of 544 g / mol and a CO2 permeability coefficient of 510 Barrer. A comparison between Comparative Example 8 and Examples 1-4 shows that an excessively large molecular weight of the gelling agent leads to a significant decrease in the CO2 permeability coefficient. This is because a large molecular weight results in significant steric hindrance, which is detrimental to gas permeation. Therefore, considering the CO2 permeability coefficient of the gel-mixed matrix membrane, the molecular weight of the gelling agent should not be too high, preferably less than 500 g / mol.

[0140] The above description is merely a few embodiments of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A gel-mixed matrix membrane, characterized in that, The gel-mixed matrix membrane comprises a mixed matrix and a gelling agent; the mixed matrix comprises a polymer matrix and a filler. The gelling agent is selected from ester-based liquid organic compounds, alcohol-based liquid organic compounds, ether-based liquid organic compounds, or amine-based liquid organic compounds; the molecular weight of the gelling agent is 120-500; The ester-based liquid organic compound is selected from at least one of amyl acetate, butyl acrylate, ethyl acetoacetate, ethyl phenoxyacetate, pentaerythritol triacrylate, acetyl tributyl citrate, triethyl citrate, and tributyl citrate. The ether-type liquid organic compound is selected from at least one of ethyl phenyl ether and ethylene glycol phenyl ether; The alcoholic liquid organic compound is selected from at least one of 2-phenoxypropanol and 1-phenoxy-2-propanol; The amine liquid organic compound is selected from at least one of dimethylthiotoluene diamine and isophorone diamine; The filler is a porous filler, which is at least one of carbon nanotubes, carbon molecular sieves, hollow silica, hydrotalcite, metal-organic frameworks or covalent organic frameworks. The polymer matrix is ​​selected from at least one of polyether ester, polyimide, polyether block polyimide, and polyether urethane.

2. The gel-mixed matrix membrane according to claim 1, characterized in that, The content of the gelling agent is 1 wt% to 80 wt% of the mass of the gel-mixed matrix membrane.

3. The gel-mixed matrix membrane according to claim 1, characterized in that, The filler content is 3wt% to 35wt% of the mixed matrix.

4. A method for preparing a gel-mixed matrix membrane according to any one of claims 1 to 3, characterized in that, The gel-mixed matrix membrane is obtained by defoaming, forming a film from a casting mixture containing polymer, filler, and gelling agent, followed by vacuum treatment.

5. The preparation method according to claim 4, characterized in that, After mixing a polymer-containing solution a with a filler-containing mixture b, a gelling agent is added to obtain the casting film mixture solution.

6. The preparation method according to claim 5, characterized in that, The casting mixture was obtained by stirring after adding the gelling agent; The stirring time is 4~28h, and the stirring temperature is 20~80℃.

7. The preparation method according to claim 4, characterized in that, In the casting mixture solution, the total mass concentration of polymer, filler and gelling agent is 2wt%~30wt%.

8. The preparation method according to claim 4, characterized in that, The solvent of the casting mixture is selected from at least one of aqueous ethanol, dichloromethane, trichloroethane, ethanol, chloroform, tetrahydrofuran, diethyl ether, and acetone.

9. The preparation method according to claim 4, characterized in that, The vacuum treatment is carried out at a temperature of 15~50℃ for a duration of 36~144h.

10. The application of a gel-mixed matrix membrane according to any one of claims 1 to 3 or a gel-mixed matrix membrane prepared by the preparation method according to any one of claims 4 to 9 in gas separation.

11. The application according to claim 10, characterized in that, Application of the gel-mixed matrix membrane in the separation of gas mixtures containing CO2.

12. The application according to claim 11, characterized in that, The gas mixture contains nonpolar gases.

13. The application according to claim 12, characterized in that, The nonpolar gas includes at least one of N2, CH4, and H2.

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