Dumbbell type polyethersulfone virus-removing membrane and preparation method thereof

Abstract

The invention belongs to the technical field of membrane materials, and particularly relates to a preparation method of a dumbbell-shaped polyethersulfone virus-removing membrane, which comprises the following steps: S1, mixing a membrane-forming polymer, an amphiphilic polymer, a non-solvent pore-foaming agent and an organic solvent, stirring, dissolving and defoaming to obtain a uniform and stable membrane casting solution; s2, blade-coating the membrane casting liquid on a support body to form a liquid membrane; s3, exposing the liquid film in humidity-controllable air for a period of time, and carrying out a steam-induced phase separation process; s4, immersing the cast film obtained in the step S3 into a coagulating bath to complete phase inversion so as to form a solid-state film; s5, the formed solid membrane is sequentially subjected to water washing, hole preserving treatment and drying, and the dumbbell-shaped polyethersulfone virus-removing membrane is obtained. The compact layer in the dumbbell-shaped structure ensures the high virus rejection rate, and the porous structure with the open interior reduces the transmission resistance of water to the minimum, so that the unification of the high virus rejection rate and the high water flux is realized, and the protein transmittance is ensured to be more than 98%.

Description

Technical Field

[0001] This invention belongs to the field of membrane material technology, specifically relating to a dumbbell-shaped polyethersulfone virus-removing membrane and its preparation method. Background Technology

[0002] Membrane separation technologies, particularly ultrafiltration and nanofiltration, are critical unit operations for ensuring the viral safety of products in biopharmaceuticals, blood products, and high-end injectables. Virus removal or inactivation is a mandatory requirement of Good Manufacturing Practices (GMP) and regulatory agencies. Among these, the use of disposable virus removal filtration membranes (VRF) has become one of the most mainstream technical solutions due to its reliable physical retention mechanism, lack of chemical introduction, and minimal impact on product activity.

[0003] An ideal virus filtration membrane must simultaneously meet three core requirements: high virus removal rate, high throughput, and long-term operational stability. Currently, mainstream products on the market, such as those from some internationally renowned brands, mostly use polyethersulfone (PES) or modified PES as the membrane material. These membranes are typically prepared using non-solvent-induced phase separation (NIPS) to form microporous membranes with asymmetric structures. Their virus retention mechanism is primarily based on size exclusion, therefore requiring a sufficiently dense separation layer with an extremely narrow pore size distribution on the membrane surface to ensure complete retention of virus particles at the tens of nanometer scale (such as ΦX174 bacteriophage, approximately 27 nm in diameter; PPV virus, approximately 20 nm in diameter).

[0004] However, existing technologies present significant contradictions and challenges. To achieve extremely high virus removal guarantees (typically requiring a logarithmic removal value (LRV) ≥ 4), the membrane's surface separation layer needs to be as dense as possible. This inevitably leads to a significant decrease in membrane flux, increasing filtration time and production costs. Conversely, increasing the surface pore size to improve flux sacrifices virus retention capacity, posing safety risks. This trade-off between flux and retention rate is a long-standing technological bottleneck in the membrane field.

[0005] Furthermore, the long-term stability of the membrane is also a problem that urgently needs to be solved. To improve the hydrophilicity and porosity of the membrane, polymer additives, such as polyvinylpyrrolidone (PVP), are often added to the membrane-forming solution. However, additives such as PVP have limited compatibility with the PES matrix and are prone to leaching from the membrane during long-term use. This not only leads to the collapse or alteration of the membrane pore structure, causing fluctuations in flux and retention performance, but more seriously, the leached additives may enter the product stream, contaminating downstream products.

[0006] To overcome these bottlenecks, researchers attempted to optimize the membrane fabrication process. The NIPS method alone is insufficient for precisely controlling the pore structure of the skin layer. Vapor-induced phase separation (VIPS) was introduced as a supplementary method. Its principle involves exposing the coated liquid membrane to air with controlled humidity before it enters the coagulation bath, allowing for a slow exchange between the solvent and non-solvent (water vapor), providing a time window for pre-phase separation and curing of the membrane structure. By combining VIPS with NIPS, it is theoretically possible to better control the surface morphology and internal pore structure of the membrane, forming a gradient-varying "dumbbell-shaped" or bicontinuous structure, thereby increasing flux while maintaining high rejection rates.

[0007] However, how to utilize the combined VIPS-NIPS method and find a key additive that is perfectly compatible with PES, effectively controls the membrane structure, and does not dissolve, to prepare high-end virus filtration membranes with performance superior to imported products, remains a technical challenge for those skilled in the art. Therefore, developing a novel membrane formulation and process that can synergistically utilize the VIPS process and form a stable composite structure has significant industrial value and practical implications. Summary of the Invention

[0008] To address the problems mentioned in the background art, this invention proposes a dumbbell-shaped polyethersulfone virus-removing membrane and its preparation method. Through a synergistic process combining 10-polyglycerol grafted with cellulose acetate as a specific additive with VIPS-NIPS, a separation membrane with a "dumbbell-shaped" asymmetric structure was successfully prepared. This structure features an extremely thin macroporous layer on the surface, which protects the separation layer during the "pleating" process in filter cartridge preparation and improves membrane flux. Below the macroporous layer is a dense separation layer with a narrow pore size distribution, and below that is a support layer with numerous interconnected macropores. The dense layer in the dumbbell-shaped structure ensures an extremely high virus rejection rate, while the internal open porous structure minimizes water transport resistance, thus achieving a balance between high virus rejection rate and high water flux, while ensuring a protein permeability of over 98%.

[0009] The technical solution adopted by this invention to solve its technical problem is: a method for preparing a dumbbell-shaped polyethersulfone virus-removing membrane, comprising the following steps:

[0010] S1. Mix the film-forming polymer, amphiphilic polymer, non-solvent pore maker and organic solvent, stir to dissolve and degas to obtain a uniform and stable casting solution;

[0011] S2. The casting liquid is scraped onto the support to form a liquid film;

[0012] S3. Expose the liquid film to air with controlled humidity for a period of time to carry out a vapor-induced phase separation process;

[0013] S4. Immerse the cast film that has passed through S3 into the coagulation bath to complete the phase transformation and form a solid film.

[0014] S5. The solid membrane formed is sequentially washed with water, treated to preserve pores, and dried to obtain a dumbbell-shaped polyethersulfone virus-removing membrane.

[0015] Further, in S1, the film-forming polymer is polyethersulfone, with a mass percentage of 15-20 wt% in the casting solution; the amphiphilic polymer is 10-polyglycerol grafted cellulose acetate, with a mass percentage of 3-8 wt% in the casting solution; the non-solvent porogen is propylene glycol monomethyl ether, with a mass percentage of 30-50 wt% in the casting solution; and the balance is an organic solvent, namely N-methylpyrrolidone.

[0016] Furthermore, the polyglycerol-grafted cellulose acetate is obtained by dehydration condensation of polyglycerol-10 and cellulose diacetate under acidic conditions, and its molecular weight is 50,000 to 70,000 Da.

[0017] Furthermore, in S2, the support material includes PET, non-woven fabric and glass plate, with PET being preferred; the gap of the scraper used for coating is 250-350µm.

[0018] Furthermore, in S3, the relative humidity of the air with controllable humidity is 50%-70%, and the exposure time is 0.5-3 minutes.

[0019] Furthermore, in S4, the non-solvent coagulation bath is pure water, the temperature is 20-30℃, and the immersion time is 0.5-2 minutes.

[0020] Further, in S5, the water washing is soaking in deionized water for 10-14 hours; the pore preservation treatment is soaking in a glycerol solution; and the drying is drying at 50-70°C.

[0021] The present invention also provides a dumbbell-shaped polyethersulfone virus-removing membrane, which is prepared by the above-described preparation method.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] (1) This invention successfully prepared a separation membrane with a "dumbbell-shaped" asymmetric structure by combining a specific additive, 10-polyglycerol grafted with cellulose acetate, with a synergistic process of VIPS-NIPS. This structure is characterized by an extremely thin macroporous layer on the surface, which can protect the separation layer in the "pleating" process of filter preparation and improve the membrane flux; below the macroporous layer is a dense separation layer with a narrow pore size distribution, and below that is a support layer with a large number of through macropores. The dense layer in the dumbbell-shaped structure ensures an extremely high virus rejection rate, while the open porous structure inside minimizes the water transport resistance, thereby achieving a balance between high virus rejection rate and high water flux.

[0024] (2) The 10-polyglycerol grafted cellulose acetate used in this invention has good compatibility between the cellulose backbone on its molecular chain and the polyethersulfone (PES) matrix, while the long polyglycerol chains are firmly anchored to the backbone through chemical grafting. This structural design fundamentally avoids the dissolution problem of additives such as PVP.

[0025] (3) 10-Polyglycerol-grafted cellulose acetate, as a highly efficient structure modifier, can influence the exchange kinetics between solvent and non-solvent during the NIPS process after undergoing the VIPS process, slowing down the phase separation rate and promoting the formation of a more uniform and ideal bicontinuous pore structure. By adjusting the molecular weight and content of this additive, and combining it with the humidity and time of VIPS, the thickness and density of the surface dense layer, as well as the ratio of internal finger-like pores to sponge-like pores, can be precisely controlled, thus providing a flexible process window for "customizing" membrane performance for application scenarios with different virus sizes and material characteristics.

[0026] (4) The 10-polyglycerol-grafted cellulose acetate molecule is rich in hydrophilic hydroxyl groups and ether bonds, making it a permanent hydrophilic modifier introduced into the PES matrix. This not only gives the membrane long-lasting high hydrophilicity and easy wetting, reducing the pressure requirement during initial use, but also effectively reduces the adsorption and blockage of macromolecules such as proteins on the membrane surface, improves the yield of expensive proteins such as IgG, and significantly reduces processing time, endows the membrane with excellent antifouling properties, and extends the membrane's service life. Attached Figure Description

[0027] Figure 1 SEM image of the dumbbell-shaped polyethersulfone virus-removing membrane prepared in Example 1;

[0028] Figure 2 SEM image of the ultrafiltration membrane prepared in Comparative Example 1;

[0029] Figure 3 This is a SEM image of the polyethersulfone virus-removing membrane with macroporous defects prepared in Comparative Example 2. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1:

[0032] Prepare a dumbbell-shaped polyethersulfone virus-removing membrane according to the following steps:

[0033] Preparation of casting solution: 18 wt% PES, 5 wt% 10 polyglycerol grafted cellulose acetate with a molecular weight of 60000 Da and 40 wt% propylene glycol monomethyl ether were dissolved in 37 wt% N-methylpyrrolidone (NMP) solvent. The solution was stirred at 100 rpm for 12 hours at room temperature until completely dissolved, and then allowed to stand for 6 hours to remove bubbles, resulting in a clear, homogeneous and stable casting solution.

[0034] Casting and VIPS: The casting solution is poured onto the PET surface at a stable flow rate of 10 cm / s, and a 300 μm doctor blade is used to scrape the casting solution into a thin film. Then, it is passed through a 5 m long constant temperature and humidity air duct and exposed to air at 25°C and 60% RH for 2 minutes to complete the vapor-induced phase separation (VIPS) process.

[0035] Immersion precipitation phase transformation: The cast membrane that has undergone the VIPS process is immersed in a coagulation bath of deionized water at a temperature of 25°C for a residence time of 1 minute to complete the entire phase transformation process and form a solid membrane.

[0036] Post-treatment: The formed membrane was immersed in flowing deionized water for 12 hours to remove residual solvent and pore-forming agent from the membrane pores. Then, it was immersed in a 25wt% glycerol aqueous solution for 30 minutes for pore preservation treatment. Finally, it was dried in an oven at 60℃ for 30 minutes to obtain the PES virus-removing membrane. Figure 1 As shown.

[0037] Tests showed that the membrane prepared in this embodiment achieved a removal rate (LRV) of 7.5 for ΦX174 bacteriophage, a pure water flux of 1105 LMH / Bar, and an IgG protein permeability of 98.1%.

[0038] Example 2:

[0039] Prepare a dumbbell-shaped polyethersulfone virus-removing membrane according to the following steps:

[0040] Preparation of casting solution: 16 wt% PES, 7 wt% 10 polyglycerol grafted cellulose acetate with a molecular weight of 65000 Da and 35 wt% propylene glycol monomethyl ether were dissolved in 42 wt% N-methylpyrrolidone (NMP) solvent. The solution was stirred at 100 rpm for 12 hours at room temperature until completely dissolved. Then it was allowed to stand for 6 hours to remove bubbles, resulting in a clear, homogeneous and stable casting solution.

[0041] Casting and VIPS: The casting solution is poured onto the PET surface at a stable flow rate of 10 cm / s, and a 300 μm doctor blade is used to scrape the casting solution into a thin film. Then, it is passed through a 5-m long constant temperature and humidity air duct and exposed to air at 25°C and 60% RH for 3 minutes to complete the vapor-induced phase separation (VIPS) process.

[0042] Immersion precipitation phase transformation: The cast membrane that has undergone the VIPS process is immersed in a coagulation bath of deionized water at a temperature of 25°C for a residence time of 2 minutes to complete the entire phase transformation process and form a solid membrane.

[0043] Post-treatment: The formed membrane was immersed in flowing deionized water for 12 hours to remove residual solvent and pore-forming agent from the membrane pores. Then it was immersed in a 25wt% glycerol aqueous solution for 30 minutes to preserve the pores. Finally, it was dried in an oven at 60℃ for 30 minutes to obtain the PES virus-removing membrane.

[0044] Tests showed that the membrane prepared in this embodiment achieved a removal rate (LRV) of 6.4 for ΦX174 phage, a pure water flux of 1300 LMH / Bar, and an IgG protein permeability of 98.7%.

[0045] Example 3:

[0046] Prepare a dumbbell-shaped polyethersulfone virus-removing membrane according to the following steps:

[0047] Preparation of casting solution: 20 wt% PES, 3 wt% 55000 Da10 polyglycerol grafted cellulose acetate and 45 wt% propylene glycol monomethyl ether were dissolved in 32 wt% N-methylpyrrolidone (NMP) solvent. The solution was stirred at 100 rpm for 12 hours at room temperature until completely dissolved. Then it was allowed to stand for 6 hours to remove bubbles, resulting in a clear, homogeneous and stable casting solution.

[0048] Casting and VIPS: The casting solution is poured onto the PET surface at a stable flow rate of 10 cm / s, and a 300 μm doctor blade is used to scrape the casting solution into a thin film. Then, it is passed through a 5 m long constant temperature and humidity air duct and exposed to air at 25 °C and 50% RH for 0.5 minutes to complete the vapor-induced phase separation (VIPS) process.

[0049] Immersion precipitation phase transformation: The cast membrane that has undergone the VIPS process is immersed in a coagulation bath of deionized water at a temperature of 25°C for a residence time of 0.5 minutes to complete the entire phase transformation process and form a solid membrane.

[0050] Post-treatment: The formed membrane was immersed in flowing deionized water for 12 hours to remove residual solvent and pore-forming agent from the membrane pores. Then it was immersed in a 25wt% glycerol aqueous solution for 30 minutes to preserve the pores. Finally, it was dried in an oven at 60℃ for 30 minutes to obtain the PES virus-removing membrane.

[0051] Tests showed that the membrane prepared in this embodiment achieved a removal rate (LRV) of 6.8 for ΦX174 bacteriophage, a pure water flux of 663 LMH / Bar, and an IgG protein permeability of 98.3%.

[0052] Example 4:

[0053] Prepare a dumbbell-shaped polyethersulfone virus-removing membrane according to the following steps:

[0054] Preparation of casting solution: 18 wt% PES, 5 wt% 10 polyglycerol grafted cellulose acetate with a molecular weight of 70000 Da and 40 wt% propylene glycol monomethyl ether were dissolved in 37 wt% N-methylpyrrolidone (NMP) solvent. The solution was stirred at 100 rpm for 12 hours at room temperature until completely dissolved, and then allowed to stand for 6 hours to remove bubbles, resulting in a clear, homogeneous and stable casting solution.

[0055] Casting and VIPS: The casting solution is poured onto the PET surface at a stable flow rate of 10 cm / s, and a 300 μm doctor blade is used to scrape the casting solution into a thin film. Then, it is passed through a 5-m long constant temperature and humidity air duct and exposed to air at 25°C and 60% RH for 3 minutes to complete the vapor-induced phase separation (VIPS) process.

[0056] Immersion precipitation phase transformation: The cast membrane that has undergone the VIPS process is immersed in a coagulation bath of deionized water at a temperature of 25°C for a residence time of 0.5 minutes to complete the entire phase transformation process and form a solid membrane.

[0057] Post-treatment: The formed membrane was immersed in flowing deionized water for 12 hours to remove residual solvent and pore-forming agent from the membrane pores. Then it was immersed in a 25wt% glycerol aqueous solution for 30 minutes to preserve the pores. Finally, it was dried in an oven at 60℃ for 30 minutes to obtain the PES virus-removing membrane.

[0058] Tests showed that the membrane prepared in this embodiment achieved a removal rate (LRV) of 6.2 for ΦX174 bacteriophage, a pure water flux of 971 LMH / Bar, and an IgG protein permeability of 98.7%.

[0059] Comparative Example 1:

[0060] Prepare an ultrafiltration membrane according to the following steps:

[0061] Preparation of casting solution: 18 wt% PES and 45 wt% propylene glycol monomethyl ether were dissolved in 37 wt% N-methylpyrrolidone (NMP) solvent. The solution was stirred at 100 rpm for 12 hours at room temperature until completely dissolved. Then, it was allowed to stand for 6 hours to remove bubbles, resulting in a clear, homogeneous and stable casting solution.

[0062] Casting and VIPS: The casting solution is poured onto the PET surface at a stable flow rate of 10 cm / s, and a 300 μm doctor blade is used to scrape the casting solution into a thin film. Then, it is passed through a 5 m long constant temperature and humidity air duct and exposed to air at 25°C and 60% RH for 2 minutes to complete the vapor-induced phase separation (VIPS) process.

[0063] Immersion precipitation phase transformation: The cast membrane that has undergone the VIPS process is immersed in a coagulation bath of deionized water at a temperature of 25°C for a residence time of 1 minute to complete the entire phase transformation process and form a solid membrane.

[0064] Post-treatment: The formed membrane was immersed in flowing deionized water for 12 hours to remove residual solvent and pore-forming agent from the membrane pores. Then, it was immersed in a 25wt% glycerol aqueous solution for 30 minutes for pore preservation treatment. Finally, it was dried in an oven at 60℃ for 30 minutes to obtain the PES virus-removing membrane. Figure 2 As shown.

[0065] Tests showed that the membrane prepared in this embodiment achieved a removal rate (LRV) of 7.0 for ΦX174 bacteriophage, a pure water flux of 510 LMH / Bar, and an IgG protein permeability of 85.2%.

[0066] Comparative Example 2:

[0067] Prepare a dumbbell-shaped polyethersulfone virus-removing membrane according to the following steps:

[0068] Preparation of casting solution: 18 wt% PES, 5 wt% 10 polyglycerol grafted cellulose acetate with a molecular weight of 70000 Da and 40 wt% propylene glycol monomethyl ether were dissolved in 37 wt% N-methylpyrrolidone (NMP) solvent. The solution was stirred at 100 rpm for 12 hours at room temperature until completely dissolved, and then allowed to stand for 6 hours to remove bubbles, resulting in a clear, homogeneous and stable casting solution.

[0069] Casting and VIPS: The casting solution is poured onto the PET surface at a stable flow rate of 10 cm / s, and a 300 μm doctor blade is used to scrape the casting solution into a thin film. Then, it is passed through a 5 m long constant temperature and humidity air duct and exposed to air at 25°C and 90% RH for 10 minutes to complete the vapor-induced phase separation (VIPS) process.

[0070] Immersion precipitation phase transformation: The cast membrane that has undergone the VIPS process is immersed in a coagulation bath of deionized water at a temperature of 25°C for a residence time of 1 minute to complete the entire phase transformation process and form a solid membrane.

[0071] Post-treatment: The formed membrane was immersed in flowing deionized water for 12 hours to remove residual solvent and pore-forming agent from the membrane pores. Then, it was immersed in a 25wt% glycerol aqueous solution for 30 minutes for pore preservation treatment. Finally, it was dried in an oven at 60℃ for 30 minutes to obtain the PES virus-removing membrane. Figure 3 As shown.

[0072] Tests showed that the membrane prepared in this embodiment had a removal rate (LRV) of less than 2 for ΦX174 phage, a pure water flux of 1732 LMH / Bar, and an IgG protein permeability of 99.5%.

[0073] Table 1 is a summary table of the virus removal membrane performance tests of Examples 1 to 4 and Comparative Examples 1 and 2.

[0074]

[0075] In summary, as shown in Table 1, the detailed descriptions and comparisons of Examples 1 to 4 and Comparative Examples 1 and 2 fully verify the effectiveness and superiority of the dumbbell-shaped polyethersulfone virus-removing membrane and its preparation method provided by this invention. This invention, by precisely controlling the composition of the casting solution and introducing 10-polyglycerol-grafted cellulose acetate with specific molecular weights and contents as key additives and membrane-forming process parameters, successfully prepared a virus-removing membrane with a unique "dumbbell-shaped" asymmetric structure. This structure achieves a perfect balance between the efficient retention of viruses by the dense surface layer and the low fluid transport resistance of the internal interconnected macroporous layer, thereby simultaneously obtaining high water flux and high virus removal rate.

[0076] Comparative results show that the absence of this amphiphilic polymer additive or deviation from the optimized VIPS process conditions prevents the formation of the ideal three-layer dumbbell structure and may lead to membrane pore defects and performance degradation. Therefore, this invention not only provides a simple, one-piece, high-performance virus-removing membrane preparation method, but also solves the problems of easy dissolution and poor durability of traditional additives through molecular design. It offers a high-throughput, stable-retention, highly resistant-to-fouling, and safe virus filtration solution for the biopharmaceutical field, demonstrating significant prospects for industrial application.

[0077] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a dumbbell-shaped polyethersulfone virus-removing membrane, characterized in that, Includes the following steps: S1. Mix the film-forming polymer, amphiphilic polymer, non-solvent pore maker and organic solvent, stir to dissolve and degas to obtain a uniform and stable casting solution; S2. The casting liquid is scraped onto the support to form a liquid film; S3. Expose the liquid film to air with controlled humidity for a period of time to carry out a vapor-induced phase separation process to obtain a cast film; S4. Immerse the cast film that has passed through S3 into the coagulation bath to complete the phase transformation and form a solid film. S5. The solid membrane formed is sequentially washed with water, treated to preserve pores, and dried to obtain a dumbbell-shaped polyethersulfone virus-removing membrane.

2. The method for preparing a dumbbell-shaped polyethersulfone virus-removing membrane according to claim 1, characterized in that, In S1, the film-forming polymer is polyethersulfone, with a mass percentage of 15-20 wt% in the casting solution; the amphiphilic polymer is 10-polyglycerol-grafted cellulose acetate, with a mass percentage of 3-8 wt% in the casting solution; the non-solvent porogen is propylene glycol monomethyl ether, with a mass percentage of 30-50 wt% in the casting solution; and the balance is an organic solvent, namely N-methylpyrrolidone.

3. The method for preparing a dumbbell-shaped polyethersulfone virus-removing membrane according to claim 2, characterized in that, The polyglycerol-grafted cellulose acetate is obtained by dehydration condensation of polyglycerol-10 and cellulose diacetate under acidic conditions, and its molecular weight is 50,000 to 70,000.

4. The method for preparing a dumbbell-shaped polyethersulfone virus-removing membrane according to claim 1, characterized in that, In S2, the support material includes PET, non-woven fabric and glass plate; the gap of the scraper used for coating is 250-350µm.

5. The method for preparing a dumbbell-shaped polyethersulfone virus-removing membrane according to claim 1, characterized in that, In S3, the relative humidity of the air with controllable humidity is 50%-70%, and the exposure time is 0.5-3 minutes.

6. The method for preparing a dumbbell-shaped polyethersulfone virus-removing membrane according to claim 1, characterized in that, In S4, the non-solvent coagulation bath is pure water, the temperature is 20-30℃, and the immersion time is 0.5-2 minutes.

7. The method for preparing a dumbbell-shaped polyethersulfone virus-removing membrane according to claim 1, characterized in that, In S5, the water washing involves soaking in deionized water for 10-14 hours; the pore preservation treatment involves soaking in a glycerol solution; and the drying involves drying at 50-70°C.

8. A dumbbell-shaped polyethersulfone virus-removing membrane, characterized in that, It is prepared by any one of claims 1 to 7.

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