Polysulfone ether porous membrane as well as preparation method and application thereof

Abstract

The invention relates to the technical field of materials, and discloses a polysulfone ether porous membrane as well as a preparation method and application thereof. The polysulfone ether porous membrane comprises a first polymer layer and a second polymer layer which are overlapped with each other, the average pore size of the first polymer layer is 55-245nm, and the porosity is 18-30%; the average pore size of the second polymer layer is 10-18 microns, and the porosity of the second polymer layer is 70%-85%; wherein the surface porosity of the polysulfone ether porous membrane is greater than or equal to 28%. The polysulfone ether porous membrane provided by the invention has an asymmetric structure, and the polysulfone ether porous membrane has an open bicontinuous structure surface, has excellent high surface porosity characteristics and high CH4 permeation rate characteristics, has relatively high permeability and selectivity to VOCs, and can be used for preparing a porous membrane for the VOCs. The composite film formed by using the composite film as a porous support layer has high separation efficiency and selectivity, can effectively adsorb and remove harmful gases such as VOCs and the like, and improves the treatment efficiency.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and particularly to the field of composite thin film technology for gas separation, specifically to a polysulfone ether porous membrane and its preparation method and application. Background Technology

[0002] Membrane separation technology is an effective means of treating volatile organic compounds (VOCs) in industry. In industrial applications, to achieve high gas throughput, the thickness of the separation membrane is sometimes reduced to 100–200 nm. In this case, to provide sufficient mechanical properties and ensure the membrane's ability to operate under large pressure differentials, the most widely used method is to prepare composite membranes by incorporating a porous support layer beneath the polymer. A typical composite membrane consists of a porous support layer and a thin, non-porous polymer layer on top. Because the porous support layer can be made of inexpensive thermoplastics, composite membranes are generally less expensive than other types of separation membranes. In practical use, the pore confinement effect of the porous support layer leads to a significant decrease in the separation performance of the composite membrane. To improve the separation efficiency of the composite membrane and mitigate the permeability and selectivity degradation caused by the pore confinement effect, preparing a support layer with high porosity is crucial.

[0003] The solvent-free phase inversion method is currently the most widely used method for preparing porous polymer membranes. It primarily relies on mass transfer between the solvent phase in the polymer solution and the non-solvent phase in the ambient atmosphere, altering the thermodynamic properties of the polymer solution and thus causing phase separation in the homogeneous polymer solution. Different preparation conditions affect the mass transfer process between the solvent and non-solvent phases, resulting in different phase separation mechanisms and ultimately different pore structures.

[0004] Currently, the porosity of typical commercially available reverse osmosis and nanofiltration membranes is generally less than 10%, which means that the pore confinement effect has a severe impact on the permeability and selectivity of composite membranes. To address this issue and further improve the porosity of porous support layers, Wu, Li, Zhu, and others have used NMP and DMF, which have excellent solubility in polymer materials, as organic solvents. They employed a vapor-induced phase separation method and optimized the preparation method and process, obtaining a series of porous support layer materials with surface porosity higher than 10%. However, the resulting surfaces all have independent pore structures, and the surface morphology is still not open enough, so the pore confinement effect of the prepared porous support layers is still very obvious. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of existing commercial porous support layers, where the high thermodynamic stability of the casting solution system hinders the phase separation process between the polymer and organic solvent during vapor induction, resulting in excessively low surface porosity of the cured porous support layer and severely impacting the performance of the composite film due to pore confinement. This invention provides a polysulfone ether porous membrane, its preparation method, and its applications. The polysulfone ether porous membrane provided by this invention has two layers with different pore sizes and porosities, and possesses an open, bicontinuous surface structure and high surface porosity.

[0006] To achieve the above objectives, the present invention provides a polysulfone ether porous membrane comprising a first polymer layer and a second polymer stacked on top of each other. The first polymer layer has an average pore size of 55-245 nm and a porosity of 18-30%. The second polymer has an average pore size of 10-18 μm and a porosity of 70-85%.

[0007] Preferably, the thickness of the first polymer layer is ≤30μm, and more preferably 1-3μm.

[0008] Preferably, the thickness of the second polymer is 150-230 μm.

[0009] Preferably, the polysulfone ether forming the polysulfone ether porous membrane is selected from one or more of BASF E6020P, E6010 and E3010.

[0010] A second aspect of the present invention provides a method for preparing a polysulfone ether porous membrane, the method comprising the following steps:

[0011] (1) Mix polysulfone ether, 2-pyrrolidone and water to obtain a casting solution;

[0012] (2) Place the fabric on the substrate, then allow the casting solution to form a polysulfone ether film liquid layer on the fabric. Next, perform vapor-induced phase separation on the polysulfone ether film liquid layer, and then place the resulting polysulfone ether porous layer in a coagulation bath to solidify it into a film; or

[0013] A polysulfone ether film liquid layer is formed on a substrate by casting solution. Then, the polysulfone ether film liquid layer is subjected to vapor-induced phase separation. Finally, the resulting polysulfone ether porous layer is placed in a coagulation bath to solidify into a film.

[0014] The conditions for the vapor-induced phase separation include: a temperature of 25-50°C, a time of 10-60 seconds, a relative humidity of 30-80%, and water vapor as the gaseous medium.

[0015] Preferably, in step (1), the polysulfone ether is selected from one or more of BASF E6020P, E6010 and E3010.

[0016] Preferably, in step (1), the weight ratio of polysulfone ether to 2-pyrrolidone is 1:6-10.

[0017] Preferably, in step (1), the weight ratio of water to 2-pyrrolidone is 0-0.1:1.

[0018] Preferably, in step (2), the polysulfone ether porous layer is placed in the coagulation bath for 6-12 hours.

[0019] Preferably, step (2) includes:

[0020] The fabric is placed on a substrate, and then a casting solution is applied to form a polysulfone ether film layer on the fabric. The substrate with the polysulfone ether film layer and the fabric is then placed in a constant temperature and humidity apparatus for vapor-induced phase separation. The resulting product is then immersed in a deionized water non-solvent bath. After the fabric with the polysulfone ether porous layer detaches from the substrate, immersion continues until the polysulfone ether porous layer solidifies into a film.

[0021] A polysulfone ether film liquid layer is formed on the substrate by casting solution. Then, the substrate with the polysulfone ether film liquid layer is placed in a constant temperature and humidity device for steam-induced phase separation. The obtained product is then immersed in a deionized water non-solvent bath. After the polysulfone ether porous layer detaches from the substrate, it is immersed until the polysulfone ether porous layer solidifies into a film.

[0022] Preferably, in step (2), the method of forming a polysulfone ether film liquid layer on the fabric or substrate by casting liquid is to drop casting liquid onto one side of the fabric or substrate and use a coating device to push the casting liquid forward until it reaches the other side of the fabric or substrate.

[0023] Preferably, the initial thickness of the coating applicator is set to 150-300 μm.

[0024] Preferably, step (2) further includes: drying the product obtained after curing into a film;

[0025] Preferably, the drying conditions include: a temperature of 40-80℃, a time of 6-12h, and a vacuum pressure of -0.08 to -0.1MPa.

[0026] A third aspect of the present invention provides a polysulfone ether porous membrane prepared by the method described above.

[0027] A fourth aspect of the present invention provides a composite film comprising a porous support layer and a polymer layer stacked on top of each other, wherein the porous support layer is the polysulfone ether porous film described above.

[0028] The fifth aspect of the present invention provides an application of the polysulfone ether porous membrane or the composite film described above in the treatment of VOCs.

[0029] Compared with the prior art, the present invention has at least the following advantages:

[0030] (1) The polysulfone ether porous membrane provided by this invention has an asymmetric structure, comprising a first polymer layer and a second polymer with different pore sizes and porosities. This polysulfone ether porous membrane has an open, bicontinuous surface structure, exhibiting excellent high surface porosity and high CH4 permeation rate characteristics. It demonstrates high permeability and selectivity for VOCs. Using it as a porous support layer to form a composite film exhibits high separation efficiency and selectivity, effectively adsorbing and removing harmful gases such as VOCs, thus improving treatment efficiency. Through composite film technology, efficient removal of VOCs can be achieved, reducing environmental pollution and harm. Therefore, the open, bicontinuous surface structure of the polysulfone ether porous membrane provided by this invention has higher porosity, which helps to significantly weaken the degradation of composite film separation performance caused by pore confinement effects, and has broad prospects for industrial applications.

[0031] (2) The method described in this invention uses a polyethersulfone / 2-pyrrolidone (PES / 2-PD) casting solution system with weak thermodynamic stability, and performs vapor-induced phase separation under specific conditions to obtain an asymmetric polysulfone ether porous membrane with a surface porosity of up to 28.69%.

[0032] (3) The polymer material selected in this invention is polyethersulfone, which has low cost, excellent heat resistance, chemical resistance and physical and mechanical properties. It is one of the few special engineering plastics that have been widely used in industry. Attached Figure Description

[0033] Figure 1 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Example 1;

[0034] Figure 2 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Comparative Example 1.

[0035] Figure 3 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Example 2;

[0036] Figure 4 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Example 3;

[0037] Figure 5 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Example 4;

[0038] Figure 6 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Example 5;

[0039] Figure 7 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Example 6;

[0040] Figure 8 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Comparative Example 2;

[0041] Figure 9 These are scanning electron microscope images of the surface and cross-section of the polysulfone ether porous membrane prepared in Comparative Example 3;

[0042] Figure 10 This is a surface pore filling diagram of the polysulfone ether porous membrane prepared in Example 1. Detailed Implementation

[0043] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0044] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0045] The polysulfone ether porous membrane provided by this invention comprises a first polymer layer and a second polymer layer stacked on top of each other. Testing shows that the average pore size of the first polymer layer is 55-245 nm, and the porosity is 18-30%; the average pore size of the second polymer layer is 10-18 μm, and the porosity is 70-85%. Scanning electron microscopy images show that the surface of the polysulfone ether porous membrane forms a bicontinuous structure with interconnected pores, and the polysulfone ether porous membrane has a relatively dense surface layer (first polymer layer) and a finger-like macropore layer (second polymer).

[0046] The polysulfone ether porous membrane provided by this invention has a high surface porosity, which greatly mitigates the degradation of composite membrane separation performance caused by pore confinement effect, and can effectively adsorb and remove harmful gases such as VOCs. In a specific embodiment, the surface porosity of the polysulfone ether porous membrane (i.e., the porosity of the first polymer layer) is 18-30%.

[0047] In this invention, the thickness of the first polymer layer (a relatively dense surface layer) has a significant impact on improving the surface porosity and CH4 permeation rate of the polysulfone ether porous membrane. In a specific embodiment, the thickness of the first polymer layer is ≤30μm, preferably 1-3μm.

[0048] In a specific embodiment, the thickness of the second polymer can be 150-230 μm.

[0049] In this invention, the polysulfone ether used to form the polysulfone ether porous membrane can be a conventional choice in the art. In a specific embodiment, the polysulfone ether used to form the polysulfone ether porous membrane is selected from one or more of BASF E6020P, E6010, and E3010.

[0050] The polysulfone ether porous membrane provided by the present invention has an asymmetric structure, namely comprising a first polymer layer and a second polymer with different pore sizes and porosities, and has an open bicontinuous structural surface. It has excellent high surface porosity characteristics and high CH4 permeation rate characteristics, and exhibits high permeability and selectivity for VOCs.

[0051] The method for preparing polysulfone ether porous membranes provided by the present invention includes the following steps:

[0052] (1) Mix polysulfone ether, 2-pyrrolidone and water to obtain a casting solution;

[0053] (2) Place the fabric on the substrate, then allow the casting solution to form a polysulfone ether film liquid layer on the fabric. Next, perform vapor-induced phase separation on the polysulfone ether film liquid layer, and then place the resulting polysulfone ether porous layer in a coagulation bath to solidify it into a film; or

[0054] A polysulfone ether film liquid layer is formed on a substrate by casting solution. Then, the polysulfone ether film liquid layer is subjected to vapor-induced phase separation. Finally, the resulting polysulfone ether porous layer is placed in a coagulation bath to solidify into a film.

[0055] In this invention, in order to obtain a polysulfone ether porous membrane with the aforementioned characteristics, the conditions for vapor-induced phase separation include: a temperature of 25-50°C, a time of 10-60 s, a relative humidity of 30-80%, and water vapor supplied from the outside as the gaseous medium.

[0056] The method described in this invention involves preparing a casting solution using specific raw materials, then subjecting the polysulfone ether membrane liquid layer to vapor-induced phase separation under specific conditions and solidifying it into a membrane in a coagulation bath, thereby obtaining a polysulfone ether porous membrane with an asymmetric structure.

[0057] In a specific implementation, the steam-induced phase separation can be carried out in a constant temperature and humidity incubator.

[0058] In specific embodiments, the polysulfone ether can be a conventional choice in the art. In specific embodiments, the polysulfone ether is selected from one or more of BASF E6020P, E6010, and E3010.

[0059] To remove water from the polysulfone ether polymer without affecting the subsequent film formation process and the resulting membrane structure, the polysulfone ether can be activated by drying before use. In a specific embodiment, the activation conditions for the polysulfone ether include: a temperature of 40-60°C, a time of 6-12 hours, and a pressure of -0.08 to -0.1 MPa.

[0060] In a preferred embodiment, the weight ratio of polysulfone ether to 2-pyrrolidone can be 1:6-10, for example, 1:6, 1:7, 1:8, 1:9 or 1:10. Limiting the amount of polysulfone ether to 2-pyrrolidone within this range can improve the surface porosity of the prepared polysulfone ether porous membrane.

[0061] In this invention, water needs to be added to prepare the casting solution. In step (1), the weight ratio of water to 2-pyrrolidone can be 0-0.1:1, preferably 0.01-0.1:1.

[0062] In a preferred embodiment, the process of preparing the casting solution includes: adding water to a 2-pyrrolidone organic solvent, stirring at room temperature to obtain a mixed solvent, then adding the activated polysulfone ether polymer to the mixed solvent, heating and stirring to obtain a clear and transparent casting solution, which is then allowed to stand to remove bubbles before use. In a specific embodiment, the heating and stirring temperature is 30-50°C, and the time is 1-2 hours. Furthermore, when stirring the polysulfone ether with the mixed solvent, the container (beaker) used to prepare the casting solution is sealed with plastic wrap to slow down the evaporation of the mixed solvent.

[0063] In step (2), the casting solution can be directly applied to the substrate to form a polysulfone ether film layer. In this way, the polysulfone ether porous membrane obtained does not have a cloth material. Alternatively, the cloth material can be placed on the substrate first, and then the casting solution can be applied to the cloth material to form a polysulfone ether film layer. In this way, the polysulfone ether porous membrane obtained has a cloth material.

[0064] In a preferred embodiment, the fabric is a non-woven fabric. In a specific embodiment, before use, the non-woven fabric can be dried in an oven at 40-60℃ for 1.5-3 hours to remove water vapor and other impurities.

[0065] In a preferred embodiment, the substrate is an acrylic sheet. In a specific embodiment, the surface of the acrylic sheet can be cleaned with anhydrous ethanol before use.

[0066] In this invention, in order to improve the surface porosity of the prepared polysulfone ether porous membrane, in a preferred embodiment, the polysulfone ether porous layer is placed in the coagulation bath for 6-12 hours in step (2).

[0067] In a specific implementation, step (2) includes:

[0068] The fabric is placed on a substrate, and then a casting solution is applied to form a polysulfone ether film layer on the fabric. The substrate with the polysulfone ether film layer and the fabric is then placed in a constant temperature and humidity apparatus for vapor-induced phase separation. The resulting product is then immersed in a deionized water non-solvent bath (coagulation bath). After the fabric with the polysulfone ether porous layer detaches from the substrate, immersion continues until the polysulfone ether porous layer solidifies into a film.

[0069] A polysulfone ether film liquid layer is formed on the substrate by casting solution. Then, the substrate with the polysulfone ether film liquid layer is placed in a constant temperature and humidity device for steam-induced phase separation. The obtained product is then immersed in a deionized water non-solvent bath (coagulation bath). After the polysulfone ether porous layer is detached from the substrate, it is immersed until the polysulfone ether porous layer solidifies into a film.

[0070] In this invention, the time the polysulfone ether porous layer is placed in the coagulation bath is the total time from when the product obtained by steam-induced phase separation is immersed in a deionized water non-solvent bath (coagulation bath) until the polysulfone ether porous layer solidifies into a film.

[0071] In a specific embodiment, the method of forming a polysulfone ether film liquid layer on a fabric or substrate by casting liquid includes: dropping the casting liquid onto one side of the fabric or substrate, and using a coating device to push the casting liquid forward until it reaches the other side of the fabric or substrate.

[0072] In a preferred embodiment, the initial thickness of the coating applicator can be set to 150-300 μm.

[0073] In a specific embodiment, step (2) further includes drying the product obtained after curing into a film. The purpose of drying is to remove residual solvent and water from the polysulfone ether porous membrane without affecting the structure of the polysulfone ether porous membrane.

[0074] In a preferred embodiment, the drying conditions include: a temperature of 40-80°C, a time of 6-12 hours, and a pressure of -0.08 to -0.1 MPa.

[0075] This invention provides a polysulfone ether porous membrane prepared by the method described above.

[0076] In a specific embodiment, the polysulfone ether porous membrane comprises a first polymer layer and a second polymer stacked on top of each other. The first polymer layer has an average pore size of 55-245 nm and a porosity of 18-30%. The second polymer has an average pore size of 10-18 μm and a porosity of 70-85%.

[0077] In a specific embodiment, the thickness of the first polymer layer is ≤30μm, preferably 1-3μm.

[0078] In a specific embodiment, the thickness of the second polymer is 150-230 μm.

[0079] The composite film provided by the present invention includes a porous support layer and a polymer layer stacked on each other, wherein the porous support layer is the polysulfone ether porous membrane or the polysulfone ether porous membrane described above.

[0080] The composite film obtained by using the polysulfone ether porous membrane described in this invention as a porous support layer has high separation efficiency and selectivity, and can effectively adsorb and remove harmful gases such as VOCs, reduce environmental pollution and harm, and improve treatment efficiency.

[0081] The composite film obtained by using the polysulfone ether porous membrane described in this invention as a porous support layer can centrally treat or recycle adsorbed VOCs, reducing VOC emissions and the risk of secondary pollution. Through the application of the composite film, VOC concentrations can be effectively reduced to below safe standards, protecting the environment and human health.

[0082] The composite film obtained by using the polysulfone ether porous membrane described in this invention as a porous support layer has wide applicability: the composite film can be adjusted according to different VOCs components and concentrations, making it suitable for different treatment scenarios and process requirements. Whether for industrial waste gas treatment or indoor air purification, the composite film can adapt to different treatment needs and provide customized solutions.

[0083] Compared to traditional treatment methods, this composite film technology has lower energy consumption and operating costs, while achieving higher treatment effectiveness and energy-saving benefits. The relatively low operation and maintenance costs of composite films can reduce treatment costs for enterprises and improve treatment effectiveness and sustainability.

[0084] This composite membrane typically has a long service life and good durability, enabling long-term and stable pollution control, which meets the requirements of sustainable development. Furthermore, the preparation process of the composite membrane does not generate harmful substances, making it environmentally friendly and consistent with the concept of sustainable development.

[0085] This composite membrane can be used not only in the field of VOCs treatment, but also in other fields such as water treatment and gas separation. With the continuous advancement of technology, the application prospects of composite membranes in the field of VOCs treatment will be even broader.

[0086] The present invention also provides an application of the polysulfone ether porous membrane or the composite film described above in the treatment of VOCs.

[0087] The present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited thereto. Unless otherwise specified, the raw materials used in the following embodiments are all common commercially available products.

[0088] In the following embodiments:

[0089] The polysulfone ether was purchased from BASF, Germany, model number E6020P.

[0090] The acrylic sheet is made of polymethyl methacrylate.

[0091] In the following embodiments:

[0092] Polysulfone ether must be activated before use. The specific activation conditions are: activation in a vacuum drying oven at 50℃ for 10 hours, with a vacuum activation pressure of -0.1MPa.

[0093] Before using the acrylic sheet, clean the surface of the acrylic sheet with anhydrous ethanol.

[0094] Before using the non-woven fabric, clean the surface of the acrylic sheet with anhydrous ethanol.

[0095] Example 1

[0096] The preparation method of polysulfone ether porous membrane is as follows:

[0097] (1) Preparation of casting solution: In a beaker, add 0.3g of deionized water to 17.7g of 2-pyrrolidone solvent and stir at room temperature for 5min to obtain a mixed solvent; add 2g of polysulfone ether to the mixed solvent, seal the mouth of the beaker, and stir at 50℃ for 2h until the polysulfone ether is completely dissolved to obtain the casting solution, and let it stand to remove bubbles for later use.

[0098] (2) Coating: After placing the nonwoven fabric on the plexiglass plate, set the coating thickness to 150μm, place the coating device at one edge of the nonwoven fabric, and slowly drip the casting liquid into the inside of the coating device using a plastic dropper. Set the coating speed to 6mm / s until the coating device reaches the other edge of the nonwoven fabric, then stop coating to form a uniform polysulfone ether film liquid layer on the surface of the nonwoven fabric.

[0099] (3) Induced phase separation: The temperature of the constant temperature and humidity incubator was set to 50℃, the gaseous medium was water vapor, and the relative humidity was set to 75%rh. After the coating was completed, the glass plate with the polysulfone ether film liquid layer and non-woven fabric was immediately transferred to the constant temperature and humidity incubator. After standing for 15s, it was taken out and immediately completely immersed in a deionized water non-solvent bath. After the non-woven fabric with the polysulfone ether porous layer was detached from the plexiglass plate, it was continued to be immersed until the polysulfone ether porous layer was cured into a film. After 6 hours, it was taken out and then the obtained polysulfone ether porous membrane was placed in a vacuum drying oven at 70℃ and -0.09MPa for 8 hours to dry.

[0100] (4) Porosity Characterization: The prepared polysulfone ether porous membrane was sputter-coated with gold for 10 seconds. After sputtering, the surface morphology of the porous support layer was photographed using a scanning electron microscope (SEM). ImageJ image processing software was used to fill the pore areas in the SEM images with color, and the surface porosity was calculated. The calculated surface porosity of the polysulfone ether porous membrane prepared in this embodiment reached 28.69%, indicating that the polysulfone ether porous membrane prepared in this embodiment exhibits extremely high porosity.

[0101] (5) Gas permeation experiment: The prepared polysulfone ether porous membrane was subjected to CH4 single-component gas permeation test using the Wicke-Kallenbach technique. Argon was used as the purge gas to reduce the influence of back diffusion on the feed side. The test temperature was 25℃, and the transmembrane pressure difference was set to 5 bar. To minimize the concentration polarization of the permeation test, the argon flow rate was set to 40 ml / min. -1 The CH4 flow rate on the feed side is set to 100 ml / min. -1 The gas permeation rate was measured using a Shimadzu GC-2014C gas chromatograph, and the stable values ​​after 15 parallel tests were taken as the final permeation rate of the polysulfone ether porous membrane. The CH4 permeation rate of the polysulfone ether porous membrane at 25℃ was measured to be 2.42 × 10⁻⁶. 5 GPU.

[0102] from Figure 1 It can be seen that the polysulfone ether porous membrane consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer layer). Figure 1 It can be seen that the polysulfone ether porous membrane prepared in this embodiment forms a bicontinuous structure with interconnected pores on its surface. Calculations show that the thickness of the relatively dense surface layer is 1 μm, and the thickness of the finger-like macropore layer is 170 μm.

[0103] After processing with ImageJ software Figure 1 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 215 nm, and the porosity is 28.69%, while the average pore size of the finger-like macropore layer is 17.4 μm, and the porosity is 74%.

[0104] from Figure 10 As can be seen, after processing the SEM image of the polysulfone ether porous membrane prepared in this embodiment using ImageJ software, the red area represents the porous area.

[0105] Example 2

[0106] The preparation method of polysulfone ether porous membrane is as follows:

[0107] (1) Preparation of casting solution: In a beaker, add 0.83g of deionized water to 13.83g of 2-pyrrolidone solvent and stir at room temperature for 5min to obtain a mixed solvent; add 2g of polysulfone ether to the mixed solvent, seal the mouth of the beaker, and stir at 40℃ for 1h until the polysulfone ether is completely dissolved to obtain the casting solution, and let it stand to remove bubbles for later use;

[0108] (2) Coating: After placing the nonwoven fabric on the plexiglass plate, set the coating thickness to 300μm, place the coating device at one edge of the nonwoven fabric, and slowly drip the casting liquid into the inside of the coating device using a plastic dropper. Set the coating speed to 6mm / s until the coating device reaches the other edge of the nonwoven fabric, then stop coating to form a uniform polysulfone ether film liquid layer on the surface of the nonwoven fabric.

[0109] (3) Induced phase separation: The temperature of the constant temperature and humidity incubator was set to 30℃, the gaseous medium was water vapor, and the relative humidity was set to 50%rh. After the coating was completed, the glass plate with the polysulfone ether film liquid layer and non-woven fabric was immediately transferred to the constant temperature and humidity incubator. After standing for 30 seconds, it was taken out and then immediately completely immersed in a deionized water non-solvent bath. After the non-woven fabric with the polysulfone ether porous layer was detached from the plexiglass plate, it was continued to be immersed until the polysulfone ether porous layer solidified into a film. After 8 hours, it was taken out and then the obtained polysulfone ether porous membrane was placed in a vacuum drying oven at 50℃ and -0.1MPa for 8 hours to dry.

[0110] (4) Porosity Characterization: The prepared polysulfone ether porous membrane was sputter-coated with gold for 10 seconds. After sputtering, the surface morphology of the porous support layer was captured using a scanning electron microscope (SEM). ImageJ image processing software was used to fill the pore areas in the SEM images with color, and the surface porosity was calculated. The calculated surface porosity of the polysulfone ether porous membrane prepared in this embodiment reached 24.38%, indicating that the polysulfone ether porous membrane prepared in this embodiment exhibits extremely high porosity.

[0111] (5) Gas permeation experiment: The prepared polysulfone ether porous membrane was subjected to CH4 single-component gas permeation test using the Wicke-Kallenbach technique. Argon was used as the purge gas to reduce the influence of back diffusion on the feed side. The test temperature was 25℃, and the transmembrane pressure difference was set to 5 bar. To minimize the concentration polarization of the permeation test, the argon flow rate was set to 40 ml / min. -1 The CH4 flow rate on the feed side is set to 100 ml / min. -1 The gas permeation rate was measured using a Shimadzu GC-2014C gas chromatograph, and the stable values ​​after 15 parallel tests were taken as the final permeation rate of the polysulfone ether porous membrane. The CH4 permeation rate of the polysulfone ether porous membrane at 25℃ was measured to be 1.90 × 10⁻⁶. 5 GPU.

[0112] from Figure 3 As can be seen, the polysulfone ether porous membrane consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer). The polysulfone ether porous membrane prepared in this embodiment forms a bicontinuous surface structure. Calculations show that the thickness of the relatively dense surface layer is 1.5 μm, and the thickness of the finger-like macroporous layer is 180 μm.

[0113] After processing with ImageJ software Figure 3 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 115 nm, with a porosity of 24.38%, while the average pore size of the finger-like macropore layer is 12.4 μm, with a porosity of 70.5%.

[0114] Example 3

[0115] The preparation method of polysulfone ether porous membrane is as follows:

[0116] (1) Preparation of casting solution: In a beaker, add 0.50g of deionized water to 14.17g of 2-pyrrolidone solvent and stir at room temperature for 5min to obtain a mixed solvent; add 2g of polysulfone ether to the mixed solvent, seal the mouth of the beaker, and stir at 40℃ for 2h until the polysulfone ether is completely dissolved to obtain the casting solution, and let it stand to remove bubbles for later use.

[0117] (2) Coating: After placing the nonwoven fabric on the plexiglass plate, set the coating thickness to 150μm, place the coating device at one edge of the nonwoven fabric, and slowly drip the casting liquid into the inside of the coating device using a plastic dropper. Set the coating speed to 6mm / s until the coating device reaches the other edge of the nonwoven fabric, then stop coating to form a uniform polysulfone ether film liquid layer on the surface of the nonwoven fabric.

[0118] (3) Induced phase separation: The temperature of the constant temperature and humidity incubator was set to 30℃, the gaseous medium was water vapor, and the relative humidity was set to 65%rh. After the coating was completed, the glass plate with the polysulfone ether film liquid layer and non-woven fabric was immediately transferred to the constant temperature and humidity incubator. After standing for 60s, it was taken out and immediately completely immersed in a deionized water non-solvent bath. After the non-woven fabric with the polysulfone ether porous layer was detached from the plexiglass plate, it was immersed until the polysulfone ether porous layer solidified into a film. After 6h, it was taken out and then the obtained polysulfone ether porous membrane was placed in a vacuum drying oven at 50℃ and -0.08MPa for 6h to further dry.

[0119] (4) Porosity Characterization: The prepared polysulfone ether porous membrane was sputter-coated with gold for 10 seconds. After sputtering, the surface morphology of the porous support layer was captured using a scanning electron microscope (SEM). ImageJ image processing software was used to fill the pore areas in the SEM images with color, and the surface porosity was calculated. The calculated surface porosity of the polysulfone ether porous membrane prepared in this embodiment reached 20.43%, indicating that the polysulfone ether porous membrane prepared in this embodiment exhibits extremely high porosity.

[0120] (5) Gas permeation experiment: The prepared polysulfone ether porous membrane was subjected to CH4 single-component gas permeation test using the Wicke-Kallenbach technique. Argon was used as the purge gas to reduce the influence of back diffusion on the feed side. The test temperature was 25℃, and the transmembrane pressure difference was set to 5 bar. To minimize the concentration polarization of the permeation test, the argon flow rate was set to 40 ml / min. -1 The CH4 flow rate on the feed side is set to 100 ml / min. -1 The gas permeation rate was measured using a Shimadzu GC-2014C gas chromatograph, and the stable values ​​after 15 parallel tests were taken as the final permeation rate of the polysulfone ether porous membrane. The CH4 permeation rate of the polysulfone ether porous membrane at 25℃ was measured to be 5.68 × 10⁻⁶. 4 GPU.

[0121] from Figure 4 As can be seen, the polysulfone ether porous membrane consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer). The polysulfone ether porous membrane prepared in this embodiment forms a bicontinuous structure surface with interconnected pores. Calculations show that the thickness of the relatively dense surface layer is 29.3 μm, and the thickness of the finger-like macroporous layer is 150 μm.

[0122] After processing with ImageJ software Figure 4 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 209 nm, and the porosity is 20.43%. The average pore size of the finger-like macroporous layer is 17.8 μm, and the porosity is 84.3%.

[0123] Example 4

[0124] The preparation method of polysulfone ether porous membrane is as follows:

[0125] (1) Preparation of casting solution: In a beaker, add 0.40g of deionized water to 12.89g of 2-pyrrolidone solvent and stir at room temperature for 5min to obtain a mixed solvent; add 2g of polysulfone ether to the mixed solvent, seal the beaker, and stir at 40℃ for 2h until the polysulfone ether is completely dissolved to obtain the casting solution, and let it stand to remove bubbles for later use.

[0126] (2) Coating: After placing the nonwoven fabric on the plexiglass plate, set the coating thickness to 150μm, place the coating device at one edge of the nonwoven fabric, and slowly drip the casting liquid into the inside of the coating device using a plastic dropper. Set the coating speed to 6mm / s until the coating device reaches the other edge of the nonwoven fabric, then stop coating to form a uniform polysulfone ether film liquid layer on the surface of the nonwoven fabric.

[0127] (3) Induced phase separation: The temperature of the constant temperature and humidity incubator was set to 50℃, the gaseous medium was water vapor, and the relative humidity was set to 45%rh. After the coating was completed, the glass plate with the polysulfone ether film liquid layer and non-woven fabric was immediately transferred to the constant temperature and humidity incubator. After standing for 10 seconds, it was taken out and then immediately completely immersed in a deionized water non-solvent bath. After the non-woven fabric with the polysulfone ether porous layer was detached from the plexiglass plate, it was continued to be immersed until the polysulfone ether porous layer was cured into a film. After 6 hours, it was taken out and then the obtained polysulfone ether porous membrane was placed in a vacuum drying oven at 50℃ and -0.08MPa for 6 hours for further drying.

[0128] (4) Porosity Characterization: The prepared polysulfone ether porous membrane was sputter-coated with gold for 10 seconds. After sputtering, the surface morphology of the porous support layer was photographed using a scanning electron microscope (SEM). ImageJ image processing software was used to fill the pore areas in the SEM images with color, and the surface porosity was calculated. The calculated surface porosity of the polysulfone ether porous membrane prepared in this embodiment reached 19.80%, indicating that the polysulfone ether porous membrane prepared in this embodiment exhibits extremely high porosity.

[0129] (5) Gas permeation experiment: The prepared polysulfone ether porous membrane was subjected to CH4 single-component gas permeation test using the Wicke-Kallenbach technique. Argon was used as the purge gas to reduce the influence of back diffusion on the feed side. The test temperature was 25℃, and the transmembrane pressure difference was set to 5 bar. To minimize the concentration polarization of the permeation test, the argon flow rate was set to 40 ml / min. -1 The CH4 flow rate on the feed side is set to 100 ml / min. -1 The gas permeation rate was measured using a Shimadzu GC-2014C gas chromatograph, and the stable values ​​after 15 parallel tests were taken as the final permeation rate of the polysulfone ether porous membrane. The CH4 permeation rate of the polysulfone ether porous membrane at 25℃ was measured to be 9.34 × 10⁻⁶. 4 GPU.

[0130] from Figure 5 As can be seen, the polysulfone ether porous membrane consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer). The polysulfone ether porous membrane prepared in this embodiment forms a bicontinuous structure surface with interconnected pores. Calculations show that the thickness of the relatively dense surface layer is 1.8 μm, and the thickness of the finger-like macroporous layer is 227 μm.

[0131] After processing with ImageJ software Figure 5 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 55 nm, and the porosity is 19.80%, while the average pore size of the finger-like macropore layer is 11.8 μm, and the porosity is 78.5%.

[0132] Example 5

[0133] The preparation method of polysulfone ether porous membrane is as follows:

[0134] (1) Preparation of casting solution: In a beaker, add 0.70g of deionized water to 12.29g of 2-pyrrolidone solvent and stir at room temperature for 5min to obtain a mixed solvent; add 2g of polysulfone ether to the mixed solvent, seal the mouth of the beaker, and stir at 40℃ for 2h until the polysulfone ether is completely dissolved to obtain the casting solution, and let it stand to remove bubbles for later use.

[0135] (2) Coating: After placing the nonwoven fabric on the plexiglass plate, set the coating thickness to 150μm, place the coating device at one edge of the nonwoven fabric, and slowly drip the casting liquid into the inside of the coating device using a plastic dropper. Set the coating speed to 6mm / s until the coating device reaches the other edge of the nonwoven fabric, then stop coating to form a uniform polysulfone ether film liquid layer on the surface of the nonwoven fabric.

[0136] (3) Induced phase separation: The temperature of the constant temperature and humidity incubator was set to 45℃, the gaseous medium was water vapor, and the relative humidity was set to 60%rh. After the coating was completed, the glass plate with the polysulfone ether film liquid layer and non-woven fabric was immediately transferred to the constant temperature and humidity incubator. After standing for 40s, it was taken out and immediately completely immersed in a deionized water non-solvent bath. After the non-woven fabric with the polysulfone ether porous layer was detached from the plexiglass plate, it was continued to be immersed until the polysulfone ether porous layer was cured into a film. After 6h, it was taken out and then the obtained polysulfone ether porous membrane was placed in a vacuum drying oven at 50℃ and -0.09MPa for 6h to be further dried.

[0137] (4) Porosity Characterization: The prepared polysulfone ether porous membrane was sputter-coated with gold for 10 seconds. After sputtering, the surface morphology of the porous support layer was captured using a scanning electron microscope (SEM). ImageJ image processing software was used to fill the pore areas in the SEM images with color, and the surface porosity was calculated. The calculated surface porosity of the polysulfone ether porous membrane prepared in this embodiment reached 24.17%, indicating that the polysulfone ether porous membrane prepared in this embodiment exhibits extremely high porosity.

[0138] (5) Gas permeation experiment: The prepared polysulfone ether porous membrane was subjected to CH4 single-component gas permeation test using the Wicke-Kallenbach technique. Argon was used as the purge gas to reduce the influence of back diffusion on the feed side. The test temperature was 25℃, and the transmembrane pressure difference was set to 5 bar. To minimize the concentration polarization of the permeation test, the argon flow rate was set to 40 ml / min. -1 The CH4 flow rate on the feed side is set to 100 ml / min. -1 The gas permeation rate was measured using a Shimadzu GC-2014C gas chromatograph, and the stable values ​​after 15 parallel tests were taken as the final permeation rate of the polysulfone ether porous membrane. The CH4 permeation rate of the polysulfone ether porous membrane at 25℃ was measured to be 1.35 × 10⁻⁶. 5 GPU.

[0139] from Figure 6 As can be seen, the polysulfone ether porous membrane consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer). The polysulfone ether porous membrane prepared in this embodiment forms a bicontinuous structure surface with interconnected pores. Calculations show that the thickness of the relatively dense surface layer is 2 μm, and the thickness of the finger-like macroporous layer is 230 μm.

[0140] After processing with ImageJ software Figure 6 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 58 nm, and the porosity is 24.17%, while the average pore size of the finger-like macropore layer is 13.8 μm, and the porosity is 81.2%.

[0141] Example 6

[0142] The preparation method of polysulfone ether porous membrane is as follows:

[0143] (1) Preparation of casting solution: In a beaker, add 0.75g of deionized water to 13.00g of 2-pyrrolidone solvent and stir at room temperature for 5min to obtain a mixed solvent; add 2g of polysulfone ether to the mixed solvent, seal the mouth of the beaker, and stir at 40℃ for 2h until the polysulfone ether is completely dissolved to obtain the casting solution, and let it stand to remove bubbles for later use.

[0144] (2) Coating: After placing the nonwoven fabric on the plexiglass plate, set the coating thickness to 150μm, place the coating device at one edge of the nonwoven fabric, and slowly drip the casting liquid into the inside of the coating device using a plastic dropper. Set the coating speed to 6mm / s until the coating device reaches the other edge of the nonwoven fabric, then stop coating to form a uniform polysulfone ether film liquid layer on the surface of the nonwoven fabric.

[0145] (3) Induced phase separation: The temperature of the constant temperature and humidity incubator was set to 60℃, the gaseous medium was water vapor, and the relative humidity was set to 80%rh. After the coating was completed, the glass plate with the polysulfone ether film liquid layer and non-woven fabric was immediately transferred to the constant temperature and humidity incubator. After standing for 20 seconds, it was taken out and immediately completely immersed in a deionized water non-solvent bath. After the non-woven fabric with the polysulfone ether porous layer was detached from the plexiglass plate, it was immersed until the polysulfone ether porous layer solidified into a film. After 6 hours, it was taken out and then the obtained polysulfone ether porous membrane was placed in a vacuum drying oven at 50℃ and -0.09MPa for 6 hours for further drying.

[0146] (4) Porosity characterization: The prepared polysulfone ether porous membrane was sputter-coated with gold for 10 seconds. After sputtering, the surface morphology of the porous support layer was photographed using a scanning electron microscope (SEM). ImageJ image processing software was used to fill the pore areas in the SEM images with color, and the surface porosity was calculated. The calculated surface porosity of the polysulfone ether porous membrane prepared in this embodiment reached 20.97%, indicating that the polysulfone ether porous membrane prepared in this embodiment exhibits extremely high porosity.

[0147] (5) Gas permeation experiment: The prepared polysulfone ether porous membrane was subjected to CH4 single-component gas permeation test using the Wicke-Kallenbach technique. Argon was used as the purge gas to reduce the influence of back diffusion on the feed side. The test temperature was 25℃, and the transmembrane pressure difference was set to 5 bar. To minimize the concentration polarization of the permeation test, the argon flow rate was set to 40 ml / min. -1 The CH4 flow rate on the feed side is set to 100 ml / min. -1 The gas permeation rate was measured using a Shimadzu GC-2014C gas chromatograph, and the stable values ​​after 15 parallel tests were taken as the final permeation rate of the polysulfone ether porous membrane. The CH4 permeation rate of the polysulfone ether porous membrane at 25℃ was measured to be 1.21 × 10⁻⁶. 5 GPU.

[0148] from Figure 7 As can be seen, the polysulfone ether porous membrane consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer). The polysulfone ether porous membrane prepared in this embodiment forms a bicontinuous structure surface with interconnected pores. Calculations show that the thickness of the relatively dense surface layer is 4.4 μm, and the thickness of the finger-like macroporous layer is 210 μm.

[0149] After processing with ImageJ software Figure 7 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 165 nm, with a porosity of 20.97%, while the average pore size of the finger-like macroporous layer is 13.2 μm, with a porosity of 82.8%.

[0150] Comparative Example 1

[0151] No water was added in step (1) of this comparative example.

[0152] The preparation method of polysulfone ether porous membrane is as follows:

[0153] (1) Preparation of casting solution: In a beaker, add 2g of polysulfone ether to 16.2g of 2-pyrrolidone solvent, seal the mouth of the beaker, and stir at 40℃ for 1h until the polysulfone ether is completely dissolved to obtain the casting solution. Let it stand to remove bubbles and use later.

[0154] (2) Coating: After placing the nonwoven fabric on the plexiglass plate, set the coating thickness to 200μm, place the coating device at one edge of the nonwoven fabric, and slowly drip the casting liquid into the inside of the coating device using a plastic dropper. Set the coating speed to 6mm / s until the coating device reaches the other edge of the nonwoven fabric, then stop coating to form a uniform polysulfone ether film liquid layer on the surface of the nonwoven fabric.

[0155] (3) Induced phase separation: The temperature of the constant temperature and humidity incubator was set to 25℃, the gaseous medium was water vapor, and the relative humidity was set to 60% RH. After the coating was completed, the glass plate with the polysulfone ether membrane liquid layer and the non-woven fabric was immediately transferred to the constant temperature and humidity incubator. After standing for 30 seconds, it was taken out and immediately completely immersed in a deionized water non-solvent bath. After the non-woven fabric with the polysulfone ether porous layer was detached from the plexiglass plate, it was continued to be immersed until the polysulfone ether porous layer was cured into a film. After 12 hours, it was taken out and then the obtained polysulfone ether porous membrane was placed in a vacuum drying oven at 50℃ and -0.09MPa for 6 hours to dry.

[0156] (4) Porosity characterization: The prepared polysulfone ether porous membrane was sputter-coated with gold for 10 s. After sputtering, the surface morphology of the porous support layer was photographed using a scanning electron microscope (SEM). ImageJ image processing software was used to fill the pore areas in the SEM images with color, and the surface porosity was calculated. The calculated surface porosity of the polysulfone ether porous membrane prepared in Comparative Example 1 was only 13.84%.

[0157] (5) Gas permeation experiment: The prepared polysulfone ether porous membrane was subjected to CH4 single-component gas permeation test using the Wicke-Kallenbach technique. Argon was used as the purge gas to reduce the influence of back diffusion on the feed side. The test temperature was 25℃, and the transmembrane pressure difference was set to 5 bar. To minimize the concentration polarization of the permeation test, the argon flow rate was set to 40 ml / min. -1 The CH4 flow rate on the feed side is set to 100 ml / min. -1 The gas permeation rate was measured using a Shimadzu GC-2014C gas chromatograph, and the stable values ​​after 15 parallel tests were taken as the final permeation rate of the polysulfone ether porous membrane. The CH4 permeation rate of the polysulfone ether porous membrane at 25℃ was measured to be 3.88 × 10⁻⁶.4 GPU.

[0158] from Figure 2 It is known that the polysulfone ether porous membrane consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer), and the surface of the polysulfone ether porous membrane forms a porous structure with independent channels. Calculations show that the thickness of the relatively dense surface layer is 12.5 μm, and the thickness of the finger-like macroporous layer is 150 μm.

[0159] After processing with ImageJ software Figure 2 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 245 nm, and the porosity is 13.84%, while the average pore size of the finger-like macropore layer is 10.2 nm, and the porosity is 71.2%.

[0160] Comparative Example 2

[0161] The method of Example 1 was implemented, except that 2-pyrrolidone was replaced with 1-methyl-2-pyrrolidone.

[0162] The CH4 permeation rate of the porous support layer at 25℃ was measured to be 2.26 × 10⁻⁶. 4 GPU.

[0163] from Figure 8 It is known that the porous support layer consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer). The porous support layer prepared in Example 3 forms a dense surface. Calculations show that the thickness of the relatively dense surface layer is 17.4 μm, and the thickness of the finger-like macroporous layer is 215 μm.

[0164] After processing with ImageJ software Figure 8 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 72.4 nm, and the porosity is 9.1%. The average pore size of the finger-like macroporous layer is 13.6 μm, and the porosity is 83.8%.

[0165] Comparative Example 3

[0166] The method was implemented according to Example 1, except that the temperature of the steam-induced phase separation was 80°C, the time was 5s, and the relative humidity was 10%rh.

[0167] The CH4 permeation rate of the porous support layer at 25℃ was measured to be 1.98 × 10⁻⁶. 4 GPU.

[0168] from Figure 9It is known that the porous support layer consists of a relatively dense surface layer (first polymer layer) and a finger-like macroporous layer (second polymer). The porous support layer prepared in Example 3 forms a dense surface. Calculations show that the thickness of the relatively dense surface layer is 1.7 μm, and the thickness of the finger-like macroporous layer is 230 μm.

[0169] After processing with ImageJ software Figure 9 Analysis shows that the average pore size of the relatively dense surface layer of the polysulfone ether porous membrane prepared in this embodiment is 0 nm, and the porosity is 0%, while the average pore size of the finger-like macropore layer is 17.8 μm, and the porosity is 80.5%.

[0170] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A porous polysulfone ether membrane characterized in that, The polysulfone ether porous membrane comprises a first polymer layer and a second polymer layer stacked on top of each other. The first polymer layer has an average pore size of 55-245 nm and a porosity of 18-30%. The second polymer layer has an average pore size of 10-18 μm and a porosity of 70-85%.

2. The porous polysulfone ether membrane of claim 1, wherein, The thickness of the first polymer layer is ≤30μm, preferably 1-3μm.

3. The porous polysulfone ether membrane according to claim 1 or 2, wherein, The thickness of the second polymer is 150-230 μm.

4. The polysulfone ether porous membrane according to any one of claims 1-3, characterized in that, The polysulfone ether forming the polysulfone ether porous membrane is selected from one or more of BASF E6020P, E6010 and E3010.

5. A method for preparing a polysulfone ether porous membrane, characterized in that, The method includes the following steps: (1) Mix polysulfone ether, 2-pyrrolidone and water to obtain a casting solution; (2) Place the fabric on the substrate, then allow the casting solution to form a polysulfone ether film liquid layer on the fabric. Next, perform vapor-induced phase separation on the polysulfone ether film liquid layer, and then place the resulting polysulfone ether porous layer in a coagulation bath to solidify into a film; or A polysulfone ether film liquid layer is formed on a substrate by casting solution. Then, the polysulfone ether film liquid layer is subjected to vapor-induced phase separation. Finally, the resulting polysulfone ether porous layer is placed in a coagulation bath to solidify into a film. The conditions for the vapor-induced phase separation include: a temperature of 25-50°C, a time of 10-60 seconds, a relative humidity of 30-80%, and water vapor as the gaseous medium.

6. The method according to claim 5, characterized in that, In step (1), the polysulfone ether is selected from one or more of BASF E6020P, E6010 and E3010; Preferably, in step (1), the weight ratio of polysulfone ether to 2-pyrrolidone is 1:6-10; Preferably, in step (1), the weight ratio of water to 2-pyrrolidone is 0-0.1:

1.

7. The method according to claim 5 or 6, characterized in that, In step (2), the polysulfone ether porous layer is placed in the coagulation bath for 6-12 hours.

8. The method according to any one of claims 5-7, characterized in that, Step (2) includes: The fabric is placed on a substrate, and then a casting solution is applied to form a polysulfone ether film layer on the fabric. The substrate with the polysulfone ether film layer and the fabric is then placed in a constant temperature and humidity apparatus for vapor-induced phase separation. The resulting product is then immersed in a deionized water non-solvent bath. After the fabric with the polysulfone ether porous layer detaches from the substrate, immersion continues until the polysulfone ether porous layer solidifies into a film. A polysulfone ether film liquid layer is formed on the substrate by casting solution. Then, the substrate with the polysulfone ether film liquid layer is placed in a constant temperature and humidity device for steam-induced phase separation. The obtained product is then immersed in a deionized water non-solvent bath. After the polysulfone ether porous layer detaches from the substrate, it is immersed until the polysulfone ether porous layer solidifies into a film.

9. The method according to any one of claims 5-8, characterized in that, In step (2), the method of forming a polysulfone ether film liquid layer on the fabric or substrate by casting liquid is to drop casting liquid onto one side of the fabric or substrate and use a coating device to push the casting liquid forward until it reaches the other side of the fabric or substrate. Preferably, the initial thickness of the coating applicator is set to 150-300 μm.

10. The method according to any one of claims 5-9, characterized in that, Step (2) also includes: drying the product obtained after curing into a film; Preferably, the drying conditions include: a temperature of 40-80℃, a time of 6-12h, and a vacuum pressure of -0.08 to -0.1MPa.

11. A polysulfone ether porous membrane is prepared by the method according to any one of claims 5-10.

12. A composite film, characterized in that, The composite film comprises a porous support layer and a polymer layer stacked on top of each other, wherein the porous support layer is a polysulfone ether porous membrane as described in any one of claims 1-4 or a polysulfone ether porous membrane as described in claim 11.

13. The application of the polysulfone ether porous membrane according to any one of claims 1-4, the polysulfone ether porous membrane according to claim 11, or the composite film according to claim 12 in the treatment of VOCs.

Images