High flux high rejection asymmetric polyethersulfone ultrafiltration membranes and methods for making the same

Abstract

The application relates to a high-flux high-rejection asymmetric polyether sulfone ultrafiltration membrane preparation method, which comprises the following steps: S1, mixing polyether sulfone, a conventional good solvent, a volatile poor solvent and a hydrophilic additive, and then uniformly placing and defoaming at a constant temperature to obtain a casting solution; S2, pouring the casting solution on a glass carrier, uniformly coating the casting solution on the glass carrier through a stainless steel scraper to form a primary film, and then performing air evaporation induction pre-phase to obtain a membrane solution; S3, immersing the membrane solution in a coagulation bath, so that the coagulation solution invades the inside of the membrane solution and gradually diffuses inward to be solidified into a film; S4, washing the solidified film formed by using pure water, and storing the film in glycerol, and the preparation of the high-flux high-rejection asymmetric polyether sulfone ultrafiltration membrane is completed. The application is simple, convenient, efficient, economical, environment-friendly and practical, and is very beneficial to product industrialization.

Description

Technical Field

[0001] This application relates to the field of ultrafiltration membrane technology, specifically to high-flux, high-retention asymmetric polyethersulfone ultrafiltration membranes and their preparation methods. Background Technology

[0002] Ultrafiltration is a pressure-driven membrane separation technology widely used in food, pharmaceutical, chemical, and water treatment industries. Various types of ultrafiltration membranes have been commercialized to meet the needs of different industries.

[0003] Although there are different types of ultrafiltration membranes on the market, in terms of balancing small pore size and high porosity, either the skin layer is thick and the water flux is low, or the water flux is high but the strength is low and the retention is poor. Therefore, achieving both high flux and high retention remains a major challenge.

[0004] Currently, most ultrafiltration membranes are prepared using solvent-free phase separation methods. Depending on the casting solution formulation and preparation process, solvent-free phase separation can produce symmetrical or asymmetric structures. Asymmetric ultrafiltration membranes have a selective top layer that allows only desired species to pass through, while the bottom porous layer provides mechanical support, with the average pore size varying along the membrane thickness. This structure is considered an ideal structure that balances high flux and high rejection rate.

[0005] Asymmetric ultrafiltration membranes have always been a research focus in the field of membrane separation. Chinese patent CN1759924B discloses a multilayer composite asymmetric ultrafiltration membrane, but this composite ultrafiltration membrane is prepared using at least two different casting solutions. The composite process involves casting two solutions using a single casting mold, controlling the casting thickness and pore size based on the different cloud points of the two polymer solutions. This results in the first polymer solution forming a microporous layer and the second polymer solution forming the ultrafiltration layer. However, this process is cumbersome and costly. Furthermore, considering the ease with which the composite membrane layers can detach, the membrane strength is difficult to guarantee.

[0006] Chinese patent CN 114272772 A discloses an asymmetric polyethersulfone porous membrane and its preparation method. The porous membrane comprises a first porous surface, a second porous surface, and a main body located between the first and second porous surfaces. The asymmetric polyethersulfone membrane improves its hydrophilicity and optimizes its structure by adding hydrophilic additives such as polyvinylpyrrolidone, 2-[[tris(hydroxymethyl)methyl]amino]ethanesulfonic acid, and 3-aminothiophene-2-carboxamide. However, the raw materials for these hydrophilic additives are expensive, offering no price advantage, and their separation performance is not significantly improved compared to other processes.

[0007] To address the need for cost-effective and high-flux polyethersulfone (PES) ultrafiltration membranes, Chinese patent CN 114917764 A proposes a method for preparing highly selective, high-flux PES ultrafiltration membranes using monomer self-crosslinking. The prepared asymmetric planar ultrafiltration membrane exhibits a distinct layered structure, with finger-like pores in the upper lumen and a sponge-like structure in the lower layer. The presence of these finger-like pores significantly increases its porosity and results in high membrane flux; however, the finger-like pore structure does not offer advantages in terms of strength or biocompatibility.

[0008] Therefore, there is an urgent need for an asymmetric polyethersulfone ultrafiltration membrane with excellent comprehensive performance and its preparation method to solve the problems existing in the current technology.

[0009] Application content

[0010] The purpose of this application is to address the poor overall performance and compatibility of existing polyethersulfone ultrafiltration membranes, and to provide a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane and its preparation method.

[0011] To achieve the above-mentioned objectives, this application adopts the following technical solution: A method for preparing a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane includes the following steps:

[0012] S1. Polyethersulfone, a conventional good solvent, a poorly volatile solvent and a hydrophilic additive are mixed and then allowed to stand at a constant temperature to remove bubbles, thus obtaining a casting solution.

[0013] S2. Pour the casting solution onto a glass substrate and coat it onto the glass substrate with a stainless steel scraper to form a uniform nascent film. Then, induce the pre-phase formation by air evaporation to obtain the film solution.

[0014] S3. Immerse the membrane solution in the coagulation bath, so that the curing solution penetrates into the membrane solution and gradually diffuses inward to solidify into a membrane;

[0015] S4. Wash the cured membrane with pure water and store it in glycerol to complete the preparation of a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane.

[0016] Further, in step S1, the raw materials of the casting solution by weight percentage are 14-30 parts of polyethersulfone, 40-62 parts of conventional good solvent, 10-30 parts of poorly volatile solvent, and 5-20 parts of hydrophilic additive.

[0017] Preferably, the casting solution is prepared according to the weight ratio. The prepared casting solution has a certain viscosity, which will have a significant impact on the final filter membrane structure. Then, the casting solution is poured onto the carrier to form a liquid film. A uniform nascent membrane is formed by coating a glass plate with a stainless steel scraper with a thickness of 5-500 micrometers. Preferably, the coating speed is 1-4 feet / minute. More preferably, the scraper thickness is between 200-400 micrometers.

[0018] Furthermore, in step S1, the conventional good solvent includes one or more of N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and butyl lactate.

[0019] Furthermore, in step S1, the poorly volatile solvent includes one or more of 2-methoxyethanol, tert-amyl alcohol, methanol, isopropanol, hexanol, heptanol, acetone, ethyl acetate, and glycerol.

[0020] Furthermore, in step S1, the hydrophilic additive includes one or more of polyvinylpyrrolidone, polyethylene glycol, water, lithium chloride, lithium nitrate, nano-calcium carbonate, and nano-silver chloride.

[0021] Furthermore, the hydrophilic additive is a mixture of polyethylene glycol, lithium chloride, and water in a mass ratio of 10:2:1. This hydrophilic additive improves the membrane's structure and performance by being added to the casting solution system. The additives selected are polyethylene glycol, lithium chloride, and water. The viscosity of the casting solution significantly affects the structure and performance of the final filter membrane, such as influencing pore size, thickness, and flow rate. Higher viscosity promotes the formation of a small-pore, sponge-like pore structure. As a macromolecular polymer, the addition of polyethylene glycol effectively controls the system's viscosity, restricts the movement of polymer molecular chains, and effectively inhibits the formation of macropores during phase separation. Lithium chloride, as a hydrophilic inorganic salt, is a small-molecule additive. Its addition improves the mechanical strength of the filter membrane. The addition of water regulates the stability of the casting solution system, bringing the cloud point closer to the vortex line, thereby controlling the phase formation rate in the pre-evaporation process and improving the compatibility between the hydrophilic additives. The synergistic effect of these three substances improves the hydrophilicity of the solvent, accelerating polymer precipitation and phase separation during solvent-non-solvent exchange. Therefore, by adjusting the addition of hydrophilic additives and controlling the phase separation rate through process control, an asymmetric structure can be obtained.

[0022] Further, in step S2, the scraped initial ecological film is first subjected to phase separation for 0-50 seconds at an ambient temperature of 10-50℃ and a relative humidity of 20-90% to obtain a pre-phased semi-finished film as the initial ecological film.

[0023] Further, in step S2, the scraped nascent membrane is subjected to phase separation at an ambient temperature of 30-50℃ and a relative humidity of 70-90%. Under these high-temperature conditions, the volatile solvents in the membrane solution become increasingly unstable, accelerating the phase separation process. The thickness of the separation layer is controlled by the exposure time. Therefore, the formation of the separation layer in the pre-phase separation process can be effectively regulated by controlling the temperature and exposure time. Finally, the pre-phase separated membrane is immersed in a coagulation bath for further curing.

[0024] Under high temperature and humidity conditions, the exchange process between non-solvent and solvent is accelerated, while the poorly volatile solvent in the membrane solution evaporates rapidly, promoting the formation of a high-porosity skin layer. The skin layer is controlled by the pre-evaporation exposure time. After pre-evaporation, the liquid membrane is immersed in the coagulation bath. The initial mass transfer rate between the solvent in the bottom liquid membrane and the coagulation bath medium is very fast, resulting in a rapid phase separation rate and the formation of large pores. However, due to the already formed dense skin layer, the transition support layer from the skin layer to the bottom is affected by resistance, and the mass transfer rate between the solvent and the coagulation bath medium in the support layer decreases, resulting in a slower phase separation rate than the bottom layer. To avoid the formation of finger-like pore structures due to excessively rapid phase separation, hydrophilic additives can increase the viscosity of the liquid membrane. The higher the viscosity of the casting solution, the greater the mass transfer resistance between the solvent and non-solvent during the phase transformation process, which restricts the movement of polymer molecular chains and avoids the formation of large finger-like pores. Thus, this application prepares an asymmetric ultrafiltration membrane by controlling the phase separation process.

[0025] Further, in step S4, the cured film is washed with pure water and stored in 10-30 wt% glycerol.

[0026] Furthermore, in step S3, the coagulation bath consists of one or more of pure water, glycerol, and isopropanol, and the coagulation bath temperature is 10-30℃.

[0027] The high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane was prepared by the above-described method for preparing high-flux, high-retention asymmetric polyethersulfone ultrafiltration membranes.

[0028] The ultrafiltration membrane includes a sponge-like support layer and a dense separation layer. The ultrafiltration membrane is integrally formed. The thickness of the polyethersulfone ultrafiltration membrane is between 90 and 150 micrometers. Preferably, the thickness of the high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane is between 100 and 120 micrometers.

[0029] Compared with the prior art, this application has the following beneficial effects:

[0030] 1. This application controls the phase separation rate by adjusting the casting solution ratio and process. Different casting solution systems exhibit different phase separation rates at the same time. As the content of hydrophilic components in the casting solution increases, the phase separation rate of the system accelerates. The order of phase separation rates is also related to the preparation process. The skin layer is formed at the air interface during the pre-evaporation stage of the nascent membrane. At this interface, the solvent exchanges with water vapor in the air medium. During this stage, the formation of the skin layer can be controlled by adjusting the pre-evaporation temperature and time.

[0031] 2. The high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane of this application not only achieves high flux and high retention in separation performance, but also exhibits excellent mechanical strength due to its integrally formed asymmetric sponge pore structure. This stems from the asymmetric membrane structure, in which the membrane body comprises a skin layer, a bottom layer, and a porous support layer between the skin and bottom layers. The dense skin layer allows liquid to pass through but does not allow large molecules to pass through. The porous support layer consists of a continuous, interconnected network structure, with the pore diameter gradually increasing from the skin layer to the bottom layer.

[0032] 3. Furthermore, in the main structure of the polyethersulfone filter membrane provided in this application, it is clearly visible that the pore size of the outer layer surface is much smaller than that of the inner layer surface. The small pores on the outer layer surface act as a separation layer, trapping large molecules, while the large pores on the inner layer surface help improve the overall filtration speed of the membrane, resulting in shorter fluid filtration time and reduced time costs. The smaller pore size on the outer layer surface of the filter membrane contributes to improved filtration accuracy and ensures the retention capacity of the polyethersulfone filter membrane. The different pore sizes of the outer layer and the inner layer in this application indicate that the polyethersulfone filter membrane is an asymmetric membrane, ensuring both a faster overall filtration speed, a larger dirt-holding capacity, and a longer service life. Simultaneously, the sponge-like support layer between the outer layer and the inner layer better meets the requirements of practical applications in terms of strength and biocompatibility.

[0033] 4. Due to the small pore size of the micropore surface, the thickness of the skin layer should be effectively controlled to ensure the overall filtration speed of the membrane. By observing the main structure of the membrane, the entire filter membrane in this application is mainly divided into two regions in the thickness direction. The first region is the separation layer containing the skin layer, which has a small pore size and is mainly used to retain large molecules. The second region is the support layer containing the bottom layer, which has a larger pore size to provide support, and the large pore size inside the support layer allows for a faster flow rate.

[0034] 5. In this application, the membrane main structure, including the separation layer and the support layer, is connected by a continuously interconnected sponge-pore structure, with the pore diameter gradually increasing from the cortex to the bottom layer. The continuously interconnected mesh structure is also interconnected with the surfaces of the cortex and the bottom layer. This further demonstrates that the prepared asymmetric membrane is integrally formed. This continuously interconnected sponge-pore support layer is significantly stronger than the finger-pore support layer. While the finger-pore structure exhibits excellent flow velocity due to its large pores, its large pores are weaker in terms of biocompatibility and fouling capacity.

[0035] 6. The high-throughput, high-retention, asymmetric, dense skin layer prepared in this application ensures filtration accuracy, while the loose bottom support layer ensures filtration rate. At the same time, the gradient distribution of pore size ensures the membrane's dirt-holding capacity.

[0036] 7. The asymmetric ultrafiltration membrane of this application exhibits significantly improved performance compared to existing ultrafiltration membranes. This improvement is primarily due to the membrane structure; the continuously interconnected porous support layer and the ultrathin, dense skin layer play crucial roles in enhancing performance. The asymmetric structure is prepared by controlling the casting solution ratio and the phase separation process. Attached Figure Description

[0037] Figure 1 A cross-sectional scanning electron microscope image of the asymmetric polyethersulfone ultrafiltration membrane obtained in Implementation Case 1, at a magnification of 1000X;

[0038] Figure 2 A scanning electron microscope image of the cross-section of the asymmetric polyethersulfone ultrafiltration membrane obtained in Implementation Case 1, magnified by 10000X;

[0039] Figure 3 The scanning electron microscope image of the surface of the asymmetric polyethersulfone ultrafiltration membrane obtained in Implementation Case 1 is magnified to 2000X. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0041] Example 1

[0042] S1: Prepare the casting solution and cast it onto a carrier to form a liquid film; dissolve 16 parts polyethersulfone and 45 parts N-methylpyrrolidone by mechanical stirring at 50°C, then add 20 parts acetone and 10 parts hydrophilic additive, and continue mechanical stirring at 50°C until completely dissolved; the hydrophilic additive includes polyethylene glycol, lithium chloride, and water in a mass ratio of 10:2:1. Allow the dissolved casting solution to stand at a constant temperature to remove bubbles.

[0043] S2: Slowly pour the degassed casting solution onto the glass substrate and scrape the nascent film with an adjustable scraper at a speed of 2 m / min; pre-evaporate the nascent film in the air medium for 30 s; the air medium conditions are: temperature 45℃, air humidity 70%, and air flow rate 0.1 m / s, to obtain the pre-phase casting film.

[0044] S3: The pre-formed liquid film is immersed in the curing liquid along with the carrier for more than 30 seconds. The curing liquid penetrates into the interior of the liquid film and gradually diffuses inward, thereby solidifying to form a separation layer and a pre-filter layer. The coagulation bath is water and ethanol, with an alcohol content of 30% and a coagulation bath temperature of 25°C.

[0045] S4: The polyethersulfone film after phase formation is immersed in a 20% glycerol aqueous solution.

[0046] To observe the microstructure of the prepared asymmetric film, its microstructure was characterized. Figure 1 , 2 This is a cross-sectional scanning electron microscope image of the asymmetric polyethersulfone ultrafiltration membrane of Example 1. Figure 3 This is a scanning electron microscope (SEM) image of the surface of an asymmetric polyethersulfone ultrafiltration membrane. (From electron microscopy) Figure 1 , 2 The formation of an ultrathin skin layer was clearly observed. The ultrathin skin layer was formed during the pre-evaporation stage. The formed dense skin layer will delay the exchange of solvent and non-solvent, which is conducive to the formation of sponge pores.

[0047] Example 2

[0048] S1: Prepare the casting solution and cast it onto a carrier to form a liquid film; dissolve 14 parts polyethersulfone and 47 parts dimethyl sulfoxide by mechanical stirring at 50°C, then add 20 parts acetone and 10 parts hydrophilic additive, and continue mechanical stirring at 50°C until completely dissolved; the hydrophilic additive includes polyethylene glycol, lithium chloride, and water in a mass ratio of 10:2:1. Allow the dissolved casting solution to stand at a constant temperature to remove bubbles.

[0049] S2: Slowly pour the degassed casting solution onto the glass substrate and scrape the nascent film with an adjustable scraper at a speed of 2 m / min; pre-evaporate the nascent film in the air medium for 50 s; the air medium conditions are: temperature 35℃, air humidity 70%, and air flow rate 0.1 m / s, to obtain the pre-phase casting film.

[0050] S3: Immerse the pre-formed liquid film along with the carrier into the curing liquid for more than 30 seconds. The curing liquid penetrates into the interior of the liquid film and gradually diffuses inward, thereby solidifying to form a separation layer and a pre-filter layer. The coagulation bath is water, and the coagulation bath temperature is 25℃.

[0051] S4: The polyethersulfone film after phase formation is immersed in a 20% glycerol aqueous solution.

[0052] Example 3

[0053] S1: Prepare the casting solution and cast it onto a carrier to form a liquid film; dissolve 16 parts polyethersulfone and 45 parts N,N dimethylformamide by mechanical stirring at 50°C, then add 20 parts acetone and 12 parts hydrophilic additive, and continue mechanical stirring at 50°C until completely dissolved; the hydrophilic additive includes polyethylene glycol, lithium chloride, and water in a mass ratio of 10:2:1. Allow the dissolved casting solution to stand at a constant temperature to remove bubbles.

[0054] S2: Slowly pour the degassed casting solution onto the glass substrate and scrape the nascent film with an adjustable scraper at a speed of 2 m / min; pre-evaporate the nascent film in the air medium for 40 s; the air medium conditions are: temperature 45℃, air humidity 70%, and air velocity 0.1 m / s, to obtain the pre-phase casting film.

[0055] S3: The pre-formed liquid film is immersed in the curing liquid along with the carrier for more than 30 seconds. The curing liquid penetrates into the interior of the liquid film and gradually diffuses inward, thereby solidifying to form a separation layer and a pre-filter layer. The coagulation bath is water and ethanol, with an alcohol content of 30% and a coagulation bath temperature of 25°C.

[0056] S4: The polyethersulfone film after phase formation is immersed in a 20% glycerol aqueous solution.

[0057] Example 4

[0058] S1: Prepare the casting solution and cast it onto a carrier to form a liquid film; dissolve 15 parts polyethersulfone and 50 parts N-methylpyrrolidone by mechanical stirring at 50°C, then add 20 parts ethyl acetate and 8 parts hydrophilic additives, and continue mechanical stirring at 50°C until completely dissolved; the hydrophilic additives include polyethylene glycol, lithium chloride, and water in a mass ratio of 10:2:1. Allow the dissolved casting solution to stand at a constant temperature to remove bubbles.

[0059] S2: Slowly pour the degassed casting solution onto the glass substrate and scrape the nascent film with an adjustable scraper at a speed of 2 m / min; pre-evaporate the nascent film in the air medium for 30 s; the air medium conditions are: temperature 45℃, air humidity 70%, and air flow rate 0.1 m / s, to obtain the pre-phase casting film.

[0060] S3: The pre-formed liquid film is immersed in the curing liquid along with the carrier for more than 30 seconds. The curing liquid penetrates into the interior of the liquid film and gradually diffuses inward, thereby solidifying to form a separation layer and a pre-filter layer. The coagulation bath is water and ethanol, with an alcohol content of 30% and a coagulation bath temperature of 25°C.

[0061] S4: The polyethersulfone film after phase formation is immersed in a 20% glycerol aqueous solution.

[0062] Example 5

[0063] S1: Prepare the casting solution and cast it onto a carrier to form a liquid film; dissolve 16 parts polyethersulfone and 50 parts N-methylpyrrolidone by mechanical stirring at 50°C, then add 20 parts ethyl acetate and 7 parts hydrophilic additives, and continue mechanical stirring at 50°C until completely dissolved; the hydrophilic additives include polyethylene glycol, lithium chloride, and water in a mass ratio of 10:2:1. Allow the dissolved casting solution to stand at a constant temperature to remove bubbles.

[0064] S2: Slowly pour the degassed casting solution onto the glass substrate and scrape the nascent film with an adjustable scraper at a speed of 2 m / min; pre-evaporate the nascent film in the air medium for 60 s; the air medium conditions are: temperature 40℃, air humidity 70%, and air velocity 0.1 m / s, to obtain the pre-phase casting film.

[0065] S3: The pre-formed liquid film is immersed in the curing liquid along with the carrier for more than 30 seconds. The curing liquid penetrates into the interior of the liquid film and gradually diffuses inward, thereby solidifying to form a separation layer and a pre-filter layer. The coagulation bath is water and ethanol, with an alcohol content of 30% and a coagulation bath temperature of 25°C.

[0066] S4: The polyethersulfone film after phase formation is immersed in a 20% glycerol aqueous solution for moisturizing, and then dried.

[0067] To further illustrate the separation performance and mechanical strength of the obtained asymmetric ultrafiltration membrane, tangential flow filtration was used to characterize the separation performance, and the tensile strength of the asymmetric ultrafiltration membrane was measured using a tensile tester. The results are shown in the table below:

[0068]

[0069] It is evident that the flux of the asymmetric ultrafiltration membrane prepared in this application is significantly higher than that of existing ultrafiltration membranes for pure water, while the retention rates are all above 96%, demonstrating excellent separation performance. Furthermore, the prepared asymmetric ultrafiltration membrane also exhibits excellent strength. The prepared high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane effectively balances separation performance and mechanical strength.

[0070] The parts not described in detail in this application are prior art, and therefore are not described in detail in this application.

[0071] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0072] Although this document uses a significant amount of technical terminology, the possibility of using other terms is not excluded. These terms are used merely to facilitate the description and explanation of the nature of this application; interpreting them as any additional limitation would be contrary to the spirit of this application.

[0073] This application is not limited to the above-described preferred embodiments. Anyone can derive other products in various forms under the guidance of this application. However, regardless of any changes made to their shape or structure, any product with the same or similar technical solution as this application falls within the protection scope of this application.

Claims

1. A method for preparing a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane, characterized in that, Includes the following steps: S1. Polyethersulfone, a conventional good solvent, a non-volatile solvent, and a hydrophilic additive are mixed and then allowed to stand at a constant temperature to remove bubbles, thereby obtaining a casting solution; wherein, the raw materials of the casting solution by weight percentage are 14-30 parts of polyethersulfone, 40-62 parts of conventional good solvent, 10-30 parts of non-volatile solvent, and 5-20 parts of hydrophilic additive; the hydrophilic additive is a mixture of polyethylene glycol, lithium chloride, and water in a mass ratio of 10:2:1; S2. Pour the casting solution onto a glass substrate, and use a stainless steel scraper to coat the glass substrate to form a uniform nascent film. Then, induce pre-phase formation through air evaporation to obtain the film solution. S3. Immerse the membrane liquid in a coagulation bath, so that the curing liquid penetrates into the interior of the membrane liquid and gradually diffuses inward to solidify into a film; S4. Wash the cured membrane with pure water and store it in glycerol to complete the preparation of a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane.

2. The method for preparing a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane according to claim 1, characterized in that, In step S1, the conventional good solvent includes one or more of N-dimethylformamide, N-dimethylacetamide, N-methylpyrrolidone, dimethyl sulfoxide, and butyl lactate.

3. The method for preparing a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane according to claim 1, characterized in that, In step S1, the poorly volatile solvent includes one or more of 2-methoxyethanol, tert-amyl alcohol, methanol, isopropanol, hexanol, heptanol, acetone, ethyl acetate, and glycerol.

4. The method for preparing a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane according to any one of claims 1-3, characterized in that, In step S2, the scraped initial ecological film is first subjected to phase separation for 0-50 seconds at an ambient temperature of 10-50℃ and a relative humidity of 20-90%, resulting in a pre-phased semi-finished film as the initial ecological film.

5. The method for preparing a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane according to claim 4, characterized in that, In step S2, the scraped nascent membrane is separated into phases at an ambient temperature of 30-50℃ and a relative humidity of 70-90%.

6. The method for preparing a high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane according to any one of claims 1-3, characterized in that, In step S4, the cured film is washed with pure water and stored in 10-30 wt% glycerol.

7. A high-flux, high-retention asymmetric polyethersulfone ultrafiltration membrane, characterized in that, The high-throughput, high-retention asymmetric polyethersulfone ultrafiltration membrane was prepared by any one of claims 1-6.

Images