A fluorine-containing anion adsorption site modified non-interfacial polyimide-based acetylene separation membrane, a preparation method and application thereof

Abstract

This invention discloses a non-interfaceless polyimide-based acetylene separation membrane with modified fluorinated anion adsorption sites, its preparation method, and its application. The membrane comprises a continuous polymer phase and a fluorinated anion salt uniformly dispersed in the continuous polymer phase. The continuous polymer phase is a polyimide matrix containing 6FDA structural units. The fluorinated anions in the fluorinated anion salt are tetrafluoroborate and / or hexafluorophosphate. The fluorinated anions in the fluorinated anion salt act as acetylene adsorption sites, synergistically interacting with the fluorinated structures in the polyimide matrix to construct an acetylene adsorption microenvironment within the continuous polymer phase. Unlike traditional mixed matrix membranes, this invention does not rely on porous fillers such as metal-organic frameworks, molecular sieves, or covalent organic frameworks, effectively solving the non-selectivity defects caused by particle aggregation and interfacial voids in mixed matrix membranes. Furthermore, the preparation method is simple, the raw materials are readily available, and it can be used for the efficient separation of acetylene-containing gas mixtures.

Description

Technical Field

[0001] This invention belongs to the field of gas separation membrane materials and membrane separation technology, specifically relating to an interfaceless polyimide-based acetylene separation membrane with modified fluorine anion adsorption sites, its preparation method, and its application. Background Technology

[0002] Gas separation is a crucial step in chemical production, energy utilization, and resource value enhancement processes. The separation of low-carbon hydrocarbon systems such as acetylene / ethylene and acetylene / ethane is of significant industrial importance. Because acetylene, ethylene, and ethane have similar molecular sizes and physicochemical properties, traditional separation methods often suffer from high energy consumption, complex equipment, or limited separation efficiency. Membrane separation technology, with its advantages of simple process, low energy consumption, compact equipment, and ease of continuous operation, is considered a promising technological approach in the field of low-carbon hydrocarbon separation.

[0003] Polymer membranes are currently one of the most widely used membrane materials in gas separation membranes. Among them, polyimide materials have attracted widespread attention in the field of gas separation membranes due to their good thermal stability, mechanical properties, and film-forming processability. However, traditional polyimide separation membranes mainly rely on the differences in dissolution and diffusion of gases within polymer segments to achieve separation, and their separation performance is usually limited by the trade-off between permeability and selectivity. For gas systems with similar molecular sizes and physical properties, such as acetylene / ethylene and acetylene / ethane, it is difficult to achieve ideal acetylene selective separation performance by relying solely on the free volume and size sieving effect of the polymer. Furthermore, conventional polyimide separation membranes lack binding sites that can specifically recognize acetylene molecules, therefore their selective affinity for acetylene still needs to be improved.

[0004] To improve the gas separation performance of membrane materials, existing technologies often employ methods such as introducing porous fillers like metal-organic frameworks, covalent organic frameworks, and molecular sieves into a polymer matrix to prepare mixed-matrix membranes. These methods utilize the sieving or adsorption effects of the porous fillers to improve separation performance. However, porous fillers are typically dispersed as independent particles within the polymer matrix, and the significant differences in physical properties between the filler and the polymer can easily lead to poor compatibility, manifesting as particle agglomeration, phase separation, or non-selective interfacial voids. These non-selective interfacial defects severely reduce the selectivity of the separation membrane and affect the long-term stability of the membrane material. Furthermore, the synthesis, activation, and preparation of mixed-matrix membranes using porous fillers are usually very complex, hindering the scale-up of membrane material production.

[0005] In addition, existing technologies also include methods to improve gas separation performance by introducing fluorinated ionic liquids, polyionic liquids, or fluorinated functional materials into membrane systems. For example, some PEBA / fluorinated ionic liquid blend membranes are mainly used for the separation of acidic gases such as carbon dioxide, hydrogen sulfide, and sulfur dioxide, while some polyionic liquid composite membranes mainly improve the permeability of specific gases through the acid-base interaction, hydrogen bonding, or dissolution effect of ionic liquids. Some fluorinated metal-organic framework materials can also utilize fluorinated sites to achieve acetylene / ethylene adsorption separation. However, these systems are typically geared towards acidic gas separation, ammonia separation, or porous material adsorption separation, or still rely on the composite interface between porous packing materials and polymers, without directly constructing an acetylene adsorption microenvironment formed by the synergistic effect of fluorinated anion adsorption sites and the fluorinated structure of the polymer within the polyimide continuous phase.

[0006] Therefore, existing technologies still require a polyimide-based acetylene separation membrane that does not rely on traditional porous packing materials, has few interface defects, is simple to prepare, and can construct an acetylene selective adsorption microenvironment in a polyimide continuous phase, in order to improve the separation performance of mixed gas systems such as acetylene / ethylene and acetylene / ethane. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides an interfaceless polyimide-based acetylene separation membrane with modified fluorine anion adsorption sites, its preparation method, and its application. This addresses the problems of insufficient selective recognition of acetylene by existing polymer gas separation membranes, the tendency of traditional mixed matrix membranes to generate interface defects between the filler and the polymer, and the complexity of porous filler preparation processes.

[0008] The technical solution provided by this invention is as follows:

[0009] This invention provides an interfaceless polyimide-based acetylene separation membrane modified with fluorinated anion adsorption sites. The acetylene separation membrane comprises a continuous polymer phase and a fluorinated anion salt uniformly dispersed in the continuous polymer phase. The continuous polymer phase is a polyimide matrix containing 6FDA structural units. The fluorinated anions in the fluorinated anion salt are tetrafluoroborate and / or hexafluorophosphate. The fluorinated anions in the fluorinated anion salt act as acetylene adsorption sites, synergistically interacting with the fluorinated structures in the polyimide matrix to construct an acetylene adsorption microenvironment within the continuous polymer phase.

[0010] Furthermore, the polyimide matrix is ​​selected from any one or more of 6FDA-Durene, 6FDA-DAM, 6FDA-ODA, 6FDA-DABA, 6FDA-mPDA, and 6FDA-PABZ.

[0011] Furthermore, the polyimide matrix is ​​6FDA-Durene.

[0012] Furthermore, the fluorinated anionic salt is tetrabutylammonium tetrafluoroborate and / or tetrabutylammonium hexafluorophosphate.

[0013] Furthermore, the fluorinated anionic salt in the acetylene separation membrane has a mass fraction of 10 wt.% to 50 wt.%. The fluorinated anionic salt is uniformly dispersed in the polyimide continuous phase, and there are no obvious particle agglomerations, through-holes, or independent phase regions in the acetylene separation membrane.

[0014] This invention also provides a method for preparing the above-described interfaceless polyimide-based acetylene separation membrane modified with fluorine-containing anion adsorption sites, the method comprising the following steps: The polyimide matrix is ​​dissolved in a first organic solvent to obtain a polyimide solution; A fluorine-containing anionic salt is dissolved in a second organic solvent to obtain a modified component solution; The modified component solution is added to the polyimide solution and mixed and stirred until uniformly dispersed to obtain a clear casting solution; The casting solution is subjected to ultrasonic degassing followed by film formation and vacuum drying to obtain the interfaceless polyimide-based acetylene separation membrane modified with fluorine anion adsorption sites.

[0015] Furthermore, the first organic solvent and the second organic solvent are each independently selected from any one or more of dichloromethane, trichloromethane, tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0016] Furthermore, the film-forming method is solution casting, film coating, coating, or spinning film formation.

[0017] Furthermore, the ultrasonic degassing conditions are 25~60 kHz for 0.5~1 h, and the vacuum drying conditions are 70~80℃ for 20~30 h.

[0018] The present invention also provides the application of the acetylene separation membrane described above or the acetylene separation membrane prepared by the above preparation method in acetylene separation. The acetylene separation membrane is used as an adsorbent, and the adsorbent is contacted with a mixture of acetylene-containing gas to achieve selective separation of acetylene. The mixture is a mixture of acetylene and ethylene, or a mixture of acetylene and ethane, or a mixture of acetylene, ethylene and ethane.

[0019] Beneficial effects

[0020] This invention introduces tetrafluoroborate and / or hexafluorophosphate adsorption sites into the polyimide continuous phase, thereby creating a synergistic effect between the fluorine-containing anion adsorption sites and the fluorine atoms on the polyimide molecular chain, constructing an acetylene adsorption microenvironment within the membrane, and thus enhancing the membrane's selective recognition ability for acetylene.

[0021] This invention does not rely on porous fillers such as metal-organic frameworks, covalent organic frameworks, or molecular sieves, and can avoid the non-selective defects caused by filler agglomeration, phase separation, and filler-polymer interface voids in traditional mixed matrix membranes under high loads.

[0022] The polyimide-based acetylene separation membrane of the present invention can be prepared by solution blending and conventional film formation process. The process is simple, the raw materials are readily available, and it is conducive to the scale-up preparation of membrane materials.

[0023] The acetylene separation membrane described in this invention can be used for the separation of low-carbon hydrocarbon systems such as acetylene / ethylene, acetylene / ethane, and acetylene / ethylene / ethane, and has application potential in the purification of acetylene and ethylene. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the interfaceless polyimide-based acetylene separation membrane modified with fluorine-containing anion adsorption sites according to the present invention.

[0025] Figure 2 This is a cross-sectional scanning electron microscope image of the 50 wt.% TBABF4 / 6FDA-Durene modified membrane in Example 1 of the present invention.

[0026] Figure 3 This is a cross-sectional scanning electron microscope image of the 50 wt.% TBAPF6 / 6FDA-Durene modified membrane in Example 2 of the present invention.

[0027] Figure 4 This is a cross-sectional scanning electron microscope image of the pure 6FDA-Durene membrane in Comparative Example 1 of this invention.

[0028] Figure 5 This is a cross-sectional scanning electron microscope image of the 50 wt.% NaBF4 / 6FDA-Durene modified membrane in Comparative Example 2 of this invention.

[0029] Figure 6 This is a cross-sectional scanning electron microscope image of the 50 wt.% KPF6 / 6FDA-Durene modified membrane in Comparative Example 3 of this invention. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are not intended to limit the present invention, but only to illustrate the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0031] This invention provides an interfaceless polyimide-based acetylene separation membrane modified with fluorine anion adsorption sites (see schematic diagram for details). Figure 1 As shown in the figure, the acetylene separation membrane comprises a polymer continuous phase and a fluorinated anion salt uniformly dispersed in the polymer continuous phase; wherein, the polymer continuous phase is a polyimide matrix containing 6FDA structural units, and the fluorinated anions in the fluorinated anion salt are tetrafluoroborate and / or hexafluorophosphate. The fluorinated anions in the fluorinated anion salt act as acetylene adsorption sites and work synergistically with the fluorinated structures in the polyimide matrix to construct an acetylene adsorption microenvironment in the polymer continuous phase.

[0032] In this embodiment, the polyimide matrix is ​​selected from any one or more of 6FDA-Durene, 6FDA-DAM, 6FDA-ODA, 6FDA-DABA, 6FDA-mPDA, and 6FDA-PABZ.

[0033] In this embodiment, the polyimide matrix is ​​6FDA-Durene.

[0034] In this embodiment, the fluorine-containing anionic salt is tetrabutylammonium tetrafluoroborate and / or tetrabutylammonium hexafluorophosphate.

[0035] In this embodiment, the fluorinated anionic salt has a mass fraction of 10 wt.% to 50 wt.% in the acetylene separation membrane. The fluorinated anionic salt is uniformly dispersed in the polyimide continuous phase, and there are no obvious particle agglomerations, through-pores, or independent phase regions in the acetylene separation membrane.

[0036] This invention also provides a method for preparing the above-described interfaceless polyimide-based acetylene separation membrane modified with fluorine-containing anion adsorption sites, the method comprising the following steps: The polyimide matrix is ​​dissolved in a first organic solvent to obtain a polyimide solution; A fluorine-containing anionic salt is dissolved in a second organic solvent to obtain a modified component solution; The modified component solution is added to the polyimide solution and mixed and stirred until uniformly dispersed to obtain a clear casting solution; The casting solution is subjected to ultrasonic degassing followed by film formation and vacuum drying to obtain the interfaceless polyimide-based acetylene separation membrane modified with fluorine anion adsorption sites.

[0037] In this embodiment, the first organic solvent and the second organic solvent are each independently selected from any one or more of dichloromethane, trichloromethane, tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0038] In this embodiment, the film-forming method is solution casting, film coating, coating, or spinning film formation.

[0039] In this embodiment, the ultrasonic degassing conditions are 25~60 kHz for 0.5~1 h, and the vacuum drying conditions are 70~80℃ for 20~30 h.

[0040] The present invention also provides the application of the acetylene separation membrane described above or the acetylene separation membrane prepared by the above preparation method in acetylene separation. The acetylene separation membrane is used as an adsorbent, and the adsorbent is contacted with a mixture of acetylene-containing gas to achieve selective separation of acetylene. The mixture is a mixture of acetylene and ethylene, or a mixture of acetylene and ethane, or a mixture of acetylene, ethylene and ethane.

[0041] Example 1: Preparation of TBABF4 / 6FDA-Durene modified membrane

[0042] This embodiment uses 6FDA-Durene polyimide as the matrix and tetrabutylammonium tetrafluoroborate (TBABF4) as the fluorinated anion salt to prepare BF4-containing compounds. - An interfaceless polyimide-based acetylene separation membrane with adsorption sites.

[0043] Weigh 0.10 g of 6FDA-Durene polyimide and add it to 1 mL of chloroform. Stir at room temperature for 24 h to obtain a polyimide solution A with a mass fraction of 10 wt.%. Weigh out the corresponding masses of TABF4 according to the mass fractions of 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.% in the final membrane sample, and add them to 1 mL of chloroform. Stir until fully dissolved to obtain solution B. Slowly add solution B to solution A at a rate of 0.1~5 mL / min; preferably, the rate is 1~2 mL / min. Continue stirring at room temperature for 24 h to uniformly disperse TABF4 in the polyimide solution, obtaining a clear casting solution.

[0044] The resulting casting solution was degassed by ultrasonication at a frequency of 25–60 kHz for 0.5–1 h. It was then poured into a horizontally placed glass petri dish, and the solvent was slowly evaporated at room temperature to form a film. After complete solvent evaporation, the membrane sample was removed and vacuum-dried at 75 °C for 24 h to remove residual solvent, yielding the TBABF4 / 6FDA-Durene modified membrane.

[0045] Example 2: Preparation of TBAPF6 / 6FDA-Durene Modified Membrane

[0046] This embodiment uses 6FDA-Durene polyimide as the matrix and tetrabutylammonium hexafluorophosphate (TBAPF6) as the fluorinated anion salt to prepare PF6-containing... - An interfaceless polyimide-based acetylene separation membrane with adsorption sites.

[0047] The preparation process was the same as in Example 1, except that TBAPF4 in Example 1 was replaced with TBAPF6. TBAPF6 was weighed according to the following mass fractions in the final membrane sample: 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.%. After dissolution, blending, degassing, film formation, and vacuum drying, the TBAPF6 / 6FDA-Durene modified membrane was obtained.

[0048] Comparative Example 1: Preparation of pure 6FDA-Durene polyimide film

[0049] Weigh 0.10 g of 6FDA-Durene polyimide and add it to 2 mL of chloroform. Stir at room temperature for 24 h to obtain a polyimide casting solution with a mass fraction of 5 wt.%. After ultrasonic degassing of the casting solution for 1 h, pour it into a horizontally placed glass petri dish and allow the solvent to evaporate slowly at room temperature to form a film. After the solvent has completely evaporated, remove the membrane sample and place it in a vacuum dryer at 75 °C for 24 h to obtain a pure 6FDA-Durene polyimide membrane.

[0050] Comparative Example 2: Preparation of NaBF4 / 6FDA-Durene Modified Membrane

[0051] This comparative example illustrates the effect of different cations on the dispersion state of fluorinated anionic salts in a polyimide matrix.

[0052] Weigh 0.10 g of 6FDA-Durene polyimide and add it to 1 mL of chloroform. Stir at room temperature for 24 h to obtain polyimide solution A. Weigh NaBF4 according to a final membrane sample mass fraction of 50 wt.% and add it to 1 mL of chloroform for dispersion to obtain solution B. Slowly add solution B to polyimide solution A and continue stirring at room temperature to ensure thorough mixing to obtain casting solution. After degassing the obtained casting solution, pour it into a glass petri dish and allow the solvent to evaporate at room temperature to form a membrane. Then, vacuum dry at 75 ℃ for 24 h to obtain the NaBF4 / 6FDA-Durene modified membrane.

[0053] Preparation of KPF6 / 6FDA-Durene modified membrane (Comparative Example 3)

[0054] This comparative example illustrates the effect of different cations on the dispersion state of fluorinated anionic salts in a polyimide matrix.

[0055] Weigh 0.10 g of 6FDA-Durene polyimide and add it to 1 mL of chloroform. Stir at room temperature for 24 h to obtain polyimide solution A. Weigh KPF6 according to a mass fraction of 50 wt.% and add it to 1 mL of chloroform for dispersion to obtain solution B. Slowly add solution B to polyimide solution A and continue stirring at room temperature to ensure thorough mixing to obtain casting solution. After degassing the obtained casting solution, pour it into a glass petri dish and allow the solvent to evaporate at room temperature to form a film. Then, dry under vacuum at 75 ℃ for 24 h to obtain a KPF6 / 6FDA-Durene modified film.

[0056] The membrane samples obtained in Examples 1, 2, 1, 2, and 3 were characterized structurally and tested for gas permeability. The membrane cross-sectional morphology was observed using a scanning electron microscope; gas permeability was tested using the constant volume-pressure swing method. During testing, the membrane sample was fixed in a membrane cell at 25 °C. The gas to be tested was introduced upstream, while a vacuum was maintained downstream. The gas permeability coefficient was calculated by monitoring the change in downstream pressure over time under steady-state conditions. The ideal selectivity of gas A / B was calculated by the ratio of the permeability coefficients of the two gases.

[0057] The results showed that, Figure 2 and Figure 3 As shown, after introducing TABF4 or TBAPF6, the resulting 50 wt.% TABF4 / 6FDA-Durene and 50 wt.% TBAPF6 / 6FDA-Durene modified membranes still maintained a continuous and dense membrane structure. No obvious particle aggregation, through-pores, or independent phase regions were observed within the membranes. Figure 4 The morphology of the pure 6FDA-Durene membrane remained consistent, indicating that the fluorinated anionic salt could be well dispersed in the polyimide continuous phase without causing serious damage to the polymer. However, the scanning electron microscope images of the 50 wt.% NaBF4 / 6FDA-Durene and 50 wt.% KPF6 / 6FDA-Durene modified membranes obtained by introducing NaBF4 and KPF6 showed obvious particle aggregation.

[0058] For ease of comparison, the different membrane samples are numbered as follows: D1 is a pure 6FDA-Durene membrane; S1-S5 are 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.% TBABF4 / 6FDA-Durene modified membranes, respectively; S6-S10 are 10 wt.%, 20 wt.%, 30 wt.%, 40 wt.%, and 50 wt.% TBAPF6 / 6FDA-Durene modified membranes, respectively; S11 and S12 represent 50 wt.% NaBF4 / 6FDA-Durene and 50 wt.% KPF6 / 6FDA-Durene modified membranes, respectively. The C2H2 / C2H4 separation performance of the different membrane samples is shown in Table 1.

[0059] Table 1. Comparison of C2H2 / C2H4 separation performance of different membrane samples

[0060]

[0061] Table 1 shows that, compared with the pure 6FDA-Durene membrane, the C2H2 / C2H4 separation selectivity of the modified membrane was significantly improved after introducing fluorine-containing anion adsorption sites. Specifically, the C2H2 / C2H4 selectivity of the 50 wt.% TBABF4 / 6FDA-Durene modified membrane reached 9.41, an increase of 384% compared to the pure membrane; the C2H2 / C2H4 selectivity of the 50 wt.% TBABF6 / 6FDA-Durene modified membrane reached 6.46, an increase of 264% compared to the pure membrane. These results indicate that BF4… - and PF6 - The introduction of adsorption sites can significantly improve the separation selectivity of polyimide membranes for the acetylene / ethylene system. However, the gas permeability of 50 wt.% NaBF4 / 6FDA-Durene and 50 wt.% KPF6 / 6FDA-Durene modified membranes, while greatly improved due to the generation of numerous non-selective interfacial voids, lost their C2H2 / C2H4 selectivity. This demonstrates the superiority of organic cations like tetrabutylammonium over inorganic cations in this system. Figure 5 and Figure 6 ).

[0062] Meanwhile, BF4 in fluorine-containing anions - or PF6 - Fluorine-containing structures in the polyimide matrix can serve as acetylene adsorption sites, providing a favorable local environment for acetylene adsorption and transport. The synergistic effect of these two components helps to construct an acetylene adsorption microenvironment within the polyimide continuous phase, thereby improving the selective recognition and separation capability of the membrane material for acetylene.

[0063] The above embodiments are only used to illustrate specific implementations of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make appropriate adjustments to the type of polyimide, the type of fluorinated anionic salt, the type of solvent, the film-forming method, and the drying conditions without departing from the concept of the present invention, and all such adjustments should fall within the scope of protection of the present invention.

Claims

1. A non-interfaceless polyimide-based acetylene separation membrane modified with fluorine-containing anion adsorption sites, characterized in that, The acetylene separation membrane comprises a polymer continuous phase and a fluorinated anion salt uniformly dispersed in the polymer continuous phase; wherein, the polymer continuous phase is a polyimide matrix containing 6FDA structural units, and the fluorinated anions in the fluorinated anion salt are tetrafluoroborate and / or hexafluorophosphate. The fluorinated anions in the fluorinated anion salt act as acetylene adsorption sites and work synergistically with the fluorinated structures in the polyimide matrix to construct an acetylene adsorption microenvironment in the polymer continuous phase.

2. The interfaceless polyimide-based acetylene separation membrane with modified fluorine anion adsorption sites according to claim 1, characterized in that, The polyimide matrix is ​​selected from any one or more of 6FDA-Durene, 6FDA-DAM, 6FDA-ODA, 6FDA-DABA, 6FDA-mPDA, and 6FDA-PABZ.

3. The interfaceless polyimide-based acetylene separation membrane with modified fluorine anion adsorption sites according to claim 2, characterized in that, The polyimide matrix is ​​6FDA-Durene.

4. The interfaceless polyimide-based acetylene separation membrane with modified fluorine anion adsorption sites according to claim 1, characterized in that, The fluorine-containing anionic salt is tetrabutylammonium tetrafluoroborate and / or tetrabutylammonium hexafluorophosphate.

5. The interfaceless polyimide-based acetylene separation membrane with modified fluorine anion adsorption sites according to claim 1, characterized in that, The fluorine-containing anionic salt has a mass fraction of 10 wt.% to 50 wt.% in the acetylene separation membrane.

6. A method for preparing an interfaceless polyimide-based acetylene separation membrane with modified fluorine anion adsorption sites as described in any one of claims 1-5, characterized in that, The method includes the following steps: The polyimide matrix is ​​dissolved in a first organic solvent to obtain a polyimide solution; A fluorine-containing anionic salt is dissolved in a second organic solvent to obtain a modified component solution; The modified component solution is added to the polyimide solution and mixed and stirred until uniformly dispersed to obtain a clear casting solution; The casting solution is subjected to ultrasonic degassing followed by film formation and vacuum drying to obtain the interfaceless polyimide-based acetylene separation membrane modified with fluorine anion adsorption sites.

7. The preparation method according to claim 6, characterized in that, The first organic solvent and the second organic solvent are each independently selected from any one or more of dichloromethane, trichloromethane, tetrahydrofuran, N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

8. The preparation method according to claim 6, characterized in that, The film formation method is solution casting, film coating, coating or spinning film formation.

9. The preparation method according to claim 6, characterized in that, The ultrasonic degassing conditions are 25~60 kHz for 0.5~1 h, and the vacuum drying conditions are 70~80℃ for 20~30 h.

10. The application of the acetylene separation membrane according to any one of claims 1-5 or the acetylene separation membrane prepared by the preparation method according to any one of claims 6-9 in acetylene separation, characterized in that, Using the acetylene separation membrane as an adsorbent, the adsorbent is contacted with a mixture of acetylene-containing gas to achieve selective separation of acetylene; the mixture is a mixture of acetylene and ethylene, or a mixture of acetylene and ethane, or a mixture of acetylene, ethylene, and ethane.

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