Polyether sulfone hollow fiber membrane for concentration and separation and preparation method thereof

Abstract

The invention discloses a polyethersulfone hollow fiber membrane for concentration and separation and a preparation method of the polyethersulfone hollow fiber membrane. The polyethersulfone hollow fiber membrane comprises the following components in parts by weight: 10-35 parts of a polysulfone membrane material, 5-35 parts of a pore-forming agent, 25-80 parts of an amide solvent and / or a sulfoxide solvent and 0-10 parts of a non-solvent. The hollow fiber membrane provided by the invention has an inner diameter of 500-2000 [mu] m, a wall thickness of 100-300 [mu] m, a membrane aperture of 1-200 nm, a pure water ultrafiltration rate of 5-2000 ml / m < 2 >. H, and a maximum use transmembrane pressure of 50 psi. The hollow fiber membrane has strong surface affinity and strong anti-fouling performance, can effectively reduce the condition of protein adsorption, greatly prolongs the service life of tows, has high water flux and low pore size distribution, shortens the treatment time of the product, and also improves the harvesting purity of the product. Concentration and separation of products are achieved in an efficient, accurate and economical mode.

Description

Technical Field

[0001] The invention relates to the technical field of hollow fiber membranes, and in particular to a polyethersulfone hollow fiber membrane for concentration and separation and a preparation method thereof. Background Art

[0002] Hollow fiber membrane technology has become a popular separation method based on its semi-permeable membrane screening characteristics, especially for the separation and concentration of substances in the biomedical field. The core of this technology lies in the dense porous structure of the hollow fiber membrane, which transfers substances and solutions smaller than the membrane pore size to the outside of the membrane through convection and diffusion, and retains substances larger than the membrane pore size in the membrane, thereby achieving the collection or concentration of the target object, and achieving different purposes according to different membrane pore sizes.

[0003] In the preparation process of biopharmaceutical products, membrane technology is almost used throughout the whole process, so efficient and accurate separation, concentration and reduction of target substance loss are crucial. Taking the production process of protein drugs as an example, in its initial stage, extracting the target protein from the fermentation broth or cell expression system is only the initial stage of the entire production process. In order to further obtain high-purity and high-quality protein drugs, a series of strict and scientific concentration and separation steps must be carried out to remove a large number of complex impurities, including proteins, nucleic acids, endotoxins and other metabolites produced by host cells. Traditional filtration technologies, such as filter paper filtration, diatomaceous earth filtration and other conventional methods, show obvious limitations in practical applications, and their filtration efficiency is relatively low. When faced with highly complex biological fermentation broths, these traditional filtration technologies can only achieve the interception of impurities with larger particle sizes, while for impurities with small particle sizes and very similar physical and chemical properties to the target protein, their filtration efficiency is significantly reduced, and it is difficult to achieve effective separation. In particular, this type of traditional filtration technology will experience clogging and other phenomena in a short period of time in actual applications, because protein macromolecules can easily adsorb and denature on the surface of the filter medium, resulting in the formation of a protein layer on the surface of the filter medium, which ultimately causes a rapid drop in filtration flux, separation efficiency and yield rate. Since the protein adsorption that occurs in this method is mostly irreversible, separation can only be continued by replacing the filter device, which leads to a sharp increase in the cost of the filter device and the cost of product waste, which ultimately has an adverse effect on the overall treatment and effect of the separated substance.

[0004] In the preparation of cell therapy products, the supernatant obtained after the cell culture contains components with great application value and scientific significance, such as various cytokines and exosomes, as well as impurities such as cell fragments and incompletely consumed culture medium components. In actual operation, many existing filtration methods are difficult to achieve efficient removal of the above impurities and effective concentration of target components without destroying the biological activity of the active ingredients. This problem increases the difficulty of harvesting the target components and, to a certain extent, limits the subsequent development space of cell therapy products in clinical application and scientific research, becoming one of the key bottlenecks restricting further breakthroughs in this field.

[0005] The polysulfone family is widely used in the field of membrane separation due to its good mechanical properties, resistance to corrosion from acid and alkali salt solutions, high temperature resistance, and good processability. It is also one of the popular membrane materials in the biomedical field. However, the current polyethersulfone hollow fiber membranes still have many aspects that need to be further improved and optimized in actual application scenarios.

[0006] From the perspective of preparation technology, in the preparation process of hollow fiber membranes of the polysulfone family, the formula of the spinning solution and the closely related preparation conditions have a crucial influence on the performance of the final membrane. At present, although there are a variety of key raw materials such as porogens and solvents to choose from, there are still many technical challenges in order to achieve a uniform distribution of membrane pore size with an asymmetric structure. The wide distribution of membrane pore size leads to a reduction in separation accuracy and efficiency, resulting in the presence of other impurities in the target product. Specifically, some impurities with relatively large particle sizes may smoothly enter the target harvest solution with the help of those larger pore sizes, while some target components with smaller particle sizes may be accidentally retained, which will not only reduce the yield of the target product, but also increase the impurities, making it difficult for the filtered product to meet the high standards for product purity and quality in the biomedical field.

[0007] In addition, in actual use, the physicochemical properties of the surface of the polysulfone family hollow fiber membrane, such as hydrophilicity and hydrophobicity, will also have an impact on its anti-pollution ability that cannot be ignored. Given the high complexity of the feed liquid composition in the biomedical field, which contains a wide variety of biological macromolecules such as proteins, polysaccharides, lipids, and various inorganic ions, these substances are easy to interact with the membrane surface, which makes it easy for the membrane surface to adsorb impurities and gradually form a dirt layer. Once the dirt layer is formed, it will not only cause a significant decrease in the filtration flux, but also further change the surface properties of the membrane, causing the original filtration performance of the membrane to further decline, seriously affecting its filtration effect and service life. However, in terms of the current status of technological development, the actual effects achieved by existing technical means in improving the anti-pollution performance of the polysulfone family hollow fiber membrane are far from ideal. Summary of the invention

[0008] The purpose of the present invention is to provide a polyethersulfone hollow fiber membrane for concentration and separation and a preparation method thereof, so as to solve the problem of low product yield and purity caused by too wide pore size distribution of hollow fiber filtration membranes in biomedical separation and concentration in the prior art.

[0009] To achieve the above object, the present invention provides the following technical solutions: The invention provides a polyethersulfone hollow fiber membrane for concentration and separation, comprising the following components in parts by weight: 10 to 35 parts of polysulfone membrane material, 5 to 35 parts of pore former, 25 to 80 parts of amide solvent and / or sulfoxide solvent, and 0 to 10 parts of non-solvent.

[0010] Furthermore, the polysulfone membrane material includes bisphenol A polysulfone, polyethersulfone, polyarylsulfone, hydroxy polyethersulfone, and sulfonated polyethersulfone.

[0011] Furthermore, the pore-forming agent is any one or any combination of polyvinyl pyrrolidone, diethylene glycol, polyvinyl alcohol, polyethylene glycol, sodium alginate, polyacrylamide, polypropylene alcohol, and N-(2-hydroxypropyl)methylpropylamide.

[0012] Furthermore, the molecular weight of the polyvinyl pyrrolidone is 10,000-400,000, and the molecular weight of the polyethylene glycol is 1,000-20,000.

[0013] Furthermore, the different molecular weights of the polyvinyl pyrrolidone and polyethylene glycol can be used to prepare membranes with different pore sizes.

[0014] Furthermore, the amide solvent and / or sulfoxide solvent is any one or any combination of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and N,N-dimethylformamide.

[0015] Furthermore, the non-solvent is any one or any combination of purified water, methanol, propylene glycol, glycerol, n-butanol, and diethylene glycol.

[0016] The present invention also provides a method for preparing a polyethersulfone hollow fiber membrane for concentration and separation, comprising the following steps: Step 1: Preparation of spinning solution 10-35 parts of polysulfone membrane material, 5-35 parts of pore-forming agent, 25-80 parts of amide solvent and / or sulfoxide solvent, 0-10 parts of non-solvent are stirred at a temperature of 30-90°C to obtain a polymer solution, and the polymer solution is filtered, degassed and aged to obtain a spinning solution; Step 2: Preparation of core solution 0-75 parts by weight of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide and 25-100 parts by weight of pure water are prepared into a core liquid; Step 3: Dry-wet spinning The spinning solution and the core solution are extruded through the outer annular slit and the inner hole of two concentric hollow fiber spinning nozzles to form a hollow fiber membrane with a five-layer structure. The membrane is then formed in a coagulation bath through an air bath, and then stretched and wound in a plasticizing bath at a winding speed of 8-65 m / min. Step 4: Fiber post-processing Polydopamine (PDA) and poly(methacrylate sulfobetaine) (PSBMA) (PDA / PSBMA molar ratio 0-1:0.5-15) were fully dissolved in a tris (hydroxymethyl)aminomethane (Tris) buffer solution with a pH of 8.5, and the concentration of polydopamine was maintained at 2 mg / mL. The hollow fiber membrane was immersed in the solution and co-deposited at 20-40°C for 1-12 h by 20-600 kHz ultrasonic catalysis. The co-deposited hollow fiber membrane was then immersed in ethanol with a solid content of 20-100% and heat treated at 40-80°C for 2-8 h, and then dried in an oven at 30-60°C for 1-8 h to obtain the final hollow fiber membrane.

[0017] Furthermore, polydopamine acts as an adhesive and co-precipitates with poly(methacrylate sulfobetaine) to fix the poly(methacrylate sulfobetaine) on the membrane surface.

[0018] Furthermore, the specific spinning conditions in step three are as follows: the spinneret and spinning solution temperatures are maintained at 25-90°C and 25-70°C respectively, the air humidity is maintained at 10-90%, the spinning solution pressure is 0.15-0.5 MPa, the spinning speed is 3-15 ml / min, and the core liquid flow rate is 15-55 ml / min.

[0019] Furthermore, the coagulation bath is 0-20 parts by weight of any one or any combination of N,N-dimethylformamide, dimethyl sulfoxide, and N,N-dimethylacetamide or 0-20 parts by weight of any one or any combination of methanol, ethanol, and glycerol and 80-100 parts by weight of pure water.

[0020] Based on the above technical solution, the embodiments of the present invention can at least produce the following technical effects: The present invention provides a polyethersulfone hollow fiber membrane for concentration and separation and a preparation method thereof, which is used for protein purification and separation, drug extraction and purification, enzyme separation, etc. in the field of biomedicine, and can also be used in the field of blood products for concentration and impurity removal. The inner diameter of the hollow fiber membrane is 500-2000 μm, the wall thickness is 100-300 μm, the membrane pore size is 1-200 nm, and the pure water ultrafiltration rate is 5-2000 ml / m 2 .h, the maximum transmembrane pressure is 50psi. Due to the adhesive effect of dopamine, it co-precipitates with poly(methacrylic acid sulfobetaine) and fixes the latter on the membrane surface. The membrane surface is coated with poly(methacrylic acid sulfobetaine), a zwitterionic polymer. Therefore, the surface affinity of the hollow fiber membrane is increased, and the anti-fouling performance is greatly improved. It can effectively reduce protein adsorption and greatly extend the service life of the fiber bundle. The high water flux and low pore size distribution can further improve the product yield, which not only shortens the product processing time, but also improves the product harvest purity. The concentration and separation of the product is achieved in an efficient, accurate and economical way. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below; obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field without making creative work based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0022] Example 1 Add 22 parts of polyethersulfone, 6 parts of polyethylene glycol, and 72 parts of N,N-dimethylformamide into a container equipped with a stirrer, a thermometer, and a pressure gauge, and stir and dissolve them at 70-90°C for 18 hours to fully mix the spinning solution. The mixed spinning solution must be filtered first, and then placed at 50-70°C and -0.06--0.1Mpa for degassing for 8-16 hours before spinning.

[0023] The spinning solution and core solution are extruded through the outer annular seam and inner hole of two concentric hollow fiber spinning nozzles, respectively. The spinneret and spinning solution temperatures are maintained at 55°C and 50°C, respectively. The air humidity is maintained at 70-80%. The spinning solution pressure is 0.215MPa, the spinning speed is 4ml / min, and the core solution flow rate is 28ml / min. After passing through an air bath with a height of 15cm, the nascent fiber enters a coagulation bath containing 15 parts by weight of N,N-dimethylformamide and 85 parts by weight of purified water at a temperature of 30-50°C to undergo phase inversion and solidification into a film, and then is drawn and wound in a plasticizing bath at a winding speed of 16m / min.

[0024] The core liquid comprises 55 parts by weight of N,N-dimethylformamide and 45 parts by weight of purified water.

[0025] The spun hollow fiber membrane was immersed in a Tris solution with a polydopamine (PDA) concentration of 2 mg / ml and PDA:PSBMA=1:2, and co-deposited at 25-30°C for 5 hours by 40kHz ultrasonic catalysis. After being immersed in ethanol with a solid content of 30% and heat-treated at 60-70°C for 3 hours, it was dried in an oven at 45°C for 3 hours to obtain a hollow fiber membrane with a narrow pore size distribution and anti-fouling performance, with an inner fiber diameter of 1300 μm, a wall thickness of 145 μm, a pore size of 11 nm, a molecular weight cutoff of 108 kDa, a pure water ultrafiltration rate of 410 ml / m²·h, a flux recovery rate (FRR) of 85%, and a static protein adsorption content of 15.86 μg / cm².

[0026] Example 2 Add 25 parts of polysulfone, 5 parts of polyvinyl pyrrolidone, 67 parts of N,N-dimethylformamide and 3 parts of glycerol into a container equipped with a stirrer, a thermometer and a pressure gauge, and stir and dissolve them at 70-90℃ for 18 hours to fully mix the spinning solution. The mixed spinning solution must be filtered first, and then placed at 50-70℃ and -0.06--0.1Mpa for degassing for 8-16 hours before spinning.

[0027] The spinning solution and core solution are extruded through the outer annular seam and inner hole of two concentric hollow fiber spinning nozzles, respectively. The spinneret and spinning solution temperatures are maintained at 55°C and 50°C, respectively. The air humidity is maintained at 70-80%, the spinning solution pressure is 0.185MPa, the spinning speed is 3.6ml / min, and the core solution flow rate is 25ml / min. After passing through an air bath with a height of 25cm, the nascent fiber enters a coagulation bath containing 15 parts by weight of N,N-dimethylformamide and 85 parts by weight of purified water at a temperature of 30-50°C to undergo phase inversion and solidification into a film, and then is drawn and wound in a plasticizing bath at a winding speed of 14m / min.

[0028] The core liquid comprises 40 parts by weight of N,N-dimethylformamide and 60 parts by weight of purified water.

[0029] The spun hollow fiber membrane was immersed in a Tris solution with a PDA concentration of 2 mg / ml and PDA:PSBMA=1:1.5, and co-deposited at 25-30°C for 3 hours by 60kHz ultrasonic catalysis. After being immersed in ethanol with a solid content of 40% and heat-treated at 60-70°C for 3 hours, it was dried in an oven at 45°C for 3 hours to obtain a hollow fiber membrane with a narrow pore size distribution and anti-fouling performance, with an inner fiber diameter of 1250μm, a wall thickness of 135μm, a pore size of 8nm, a pure water ultrafiltration rate of 370ml / m²·h, a flux recovery rate (FRR) of 88%, and a static protein adsorption content of 25.64μg / cm².

[0030] Example 3 Add 24 parts of polyethersulfone, 6 parts of polyvinylpyrrolidone, 67 parts of N,N-dimethylacetamide and 3 parts of glycerol into a container equipped with a stirrer, a thermometer and a pressure gauge, and stir and dissolve them at 70-90℃ for 18 hours to fully mix the spinning solution. The mixed spinning solution must be filtered first, and then placed at 50-70℃ and -0.06--0.1Mpa for degassing for 8-16 hours before spinning.

[0031] The spinning solution and core solution are extruded through the outer annular seam and inner hole of two concentric hollow fiber spinning nozzles, respectively. The spinneret and spinning solution temperatures are maintained at 60°C and 55°C, respectively. The air humidity is maintained at 70-80%. The spinning solution pressure is 0.195MPa, the spinning speed is 3.8ml / min, and the core solution flow rate is 27ml / min. After passing through an air bath with a height of 20cm, the nascent fiber enters a solid bath containing 15 parts by weight of N,N-dimethylacetamide and 85 parts by weight of purified water at a temperature of 30-50°C to undergo phase inversion and solidification into a film, and then is drawn and wound in a plasticizing bath at a winding speed of 15m / min.

[0032] The core liquid comprises 62 parts by weight of N,N-dimethylformamide and 62 parts by weight of purified water.

[0033] The spun hollow fiber membrane was immersed in a Tris solution with a PDA concentration of 2 mg / ml and PDA:PSBMA=1:5, and co-deposited at 25-30°C for 3 hours by 100 Hz ultrasonic catalysis. After being immersed in ethanol with a solid content of 60% and heat-treated at 60-70°C for 4 hours, it was dried in an oven at 45°C for 3 hours to obtain a hollow fiber membrane with a narrow pore size distribution and anti-fouling performance, with an inner fiber diameter of 1350 μm, a wall thickness of 165 μm, a pore size of 22 nm, a pure water ultrafiltration rate of 430 ml / m²·h, a flux recovery rate (FRR) of 90%, and a static protein adsorption content of 13.82 μg / cm².

[0034] Example 4 The difference from Example 1 is: Add 22 parts of sulfonated polyethersulfone, 6 parts of polyethylene glycol, and 72 parts of N,N-dimethylformamide into a container equipped with a stirrer, a thermometer, and a pressure gauge, stir and dissolve them at 70-90°C for 18 hours, and fully stir the spinning solution.

[0035] Example 5 The difference from Example 1 is: Add 18 parts of bisphenol A polysulfone, polyethersulfone, polyarylsulfone, hydroxy polyethersulfone, sulfonated polyethersulfone, 6 parts of polyethylene glycol, and 76 parts of N,N-dimethylformamide into a container equipped with a stirrer, a thermometer, and a pressure gauge, stir and dissolve at 70-90°C for 18 hours, and fully mix the spinning solution.

[0036] Example 6 The difference from Example 1 is: Add 22 parts of polyethersulfone, polyvinyl alcohol, polyethylene glycol, sodium alginate, polyacrylamide, polypropylene alcohol, 13 parts of N-(2-hydroxypropyl)methylpropylamide and 94 parts of N,N-dimethylformamide into a container with a stirrer, a thermometer and a pressure gauge, stir and dissolve at 70-90°C for 18 hours, and fully mix the spinning solution.

[0037] Example 7 The difference from Example 1 is: Add 15 parts of polyethersulfone, 15 parts of polyethylene glycol and 70 parts of N,N-dimethylformamide into a container equipped with a stirrer, a thermometer and a pressure gauge, stir and dissolve them at 70-90°C for 18 hours, and fully stir the spinning solution.

[0038] Comparative Example 1 Add 25 parts of polyethersulfone, 6 parts of polyvinylpyrrolidone and 69 parts of N,N-dimethylformamide into a container equipped with a stirrer, a thermometer and a pressure gauge, and stir and dissolve them at 70-90℃ for 18 hours to fully mix the spinning solution. The mixed spinning solution must be filtered first, and then placed at 50-70℃ and -0.06--0.1Mpa for degassing for 8-16 hours before spinning.

[0039] The spinning solution and core solution are extruded through the outer annular seam and inner hole of two concentric hollow fiber spinning nozzles, respectively. The spinneret and spinning solution temperatures are maintained at 50°C and 45°C, respectively. The air humidity is maintained at 70-80%. The spinning solution pressure is 0.18MPa, the spinning speed is 3.5ml / min, and the core solution flow rate is 24ml / min. After passing through an air bath with a height of 35cm, the nascent fiber enters a coagulation bath containing 15 parts by weight of N,N-dimethylacetamide and 85 parts by weight of purified water at a temperature of 25-50°C to undergo phase inversion and solidification into a film, and then is drawn and wound in a plasticizing bath at a winding speed of 13m / min.

[0040] The core liquid comprises 48 parts by weight of N,N-dimethylformamide and 52 parts by weight of purified water.

[0041] The spun hollow fiber tow is soaked in water at a temperature of 45-50 °C for 6 hours to remove residual solvents and pore formers. The inner diameter of the fiber is 1300 μm, the pore diameter is 4.8 nm, the wall thickness is 140 μm, the flux recovery rate (FRR) is 64%, the pure water ultrafiltration rate is 160 ml / m²·h, and the static protein adsorption content is 126.35 μg / cm².

[0042] The performance tests of the hollow fiber membranes obtained in Examples 1-7 and Comparative Example 1 were carried out, and the results are shown in Table 1: Table 1 Performance test results performance Pure water contact angle (°) Static adsorption capacity of bovine serum albumin (μg / cm²) Average pore size (nm) Pure water flux recovery rate (%) Porosity (%) Example 1 43.8 15.86 11 85 78 Example 2 50.6 25.64 8 88 76 Example 3 42.5 13.82 22 90 82 Example 4 44.2 16.21 12 86 78 Example 5 44.7 15.66 11 87 77 Example 6 43.9 16.35 12 85 79 Example 7 44.8 16.16 13 86 80 Comparative Example 1 78.2 16.35 4.8 64 42 As can be seen from Table 1, after the post-treatment of the hollow fiber membrane with a PDA / PSBMA anti-fouling layer, due to the relatively strong surface affinity of the hollow fiber membrane, the water contact angle and protein adsorption amount are reduced, the pure water flux recovery rate is increased, the average pore diameter is increased through delayed phase separation, and the porosity is increased through post-treatment, which can effectively improve the efficiency and accuracy in the concentration, separation, and purification processes of biomedical products.

[0043] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the inventive concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

Claims

1. A polyethersulfone hollow fiber membrane for concentration and separation, characterized in that: The invention comprises the following components in parts by weight: 10 to 35 parts of polysulfone membrane material, 5 to 35 parts of pore-forming agent, 25 to 80 parts of amide solvent and / or sulfoxide solvent, and 0 to 10 parts of non-solvent.

2. The polyethersulfone hollow fiber membrane for concentration and separation according to claim 1, characterized in that: The polysulfone membrane materials include bisphenol A polysulfone, polyethersulfone, polyarylsulfone, hydroxy polyethersulfone and sulfonated polyethersulfone.

3. The polyethersulfone hollow fiber membrane for concentration and separation according to claim 1, characterized in that: The pore-forming agent is any one or any combination of polyvinyl pyrrolidone, diethylene glycol, polyvinyl alcohol, polyethylene glycol, sodium alginate, polyacrylamide, polyacryl alcohol, and N-(2-hydroxypropyl)methylpropylamide.

4. The polyethersulfone hollow fiber membrane for concentration and separation according to claim 3, characterized in that: The molecular weight of the polyvinyl pyrrolidone is 10,000-400,000, and the molecular weight of the polyethylene glycol is 1,000-20,000.

5. The polyethersulfone hollow fiber membrane for concentration and separation according to claim 1, characterized in that: The amide solvent and / or sulfoxide solvent is any one or any combination of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and N,N-dimethylformamide.

6. The polyethersulfone hollow fiber membrane for concentration and separation according to claim 1, characterized in that: The non-solvent is any one or any combination of purified water, methanol, propylene glycol, glycerol, n-butanol, and diethylene glycol.

7. The method for preparing a polyethersulfone hollow fiber membrane for concentration and separation according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Preparation of spinning solution 10-35 parts of polysulfone membrane material, 5-35 parts of pore-forming agent, 25-80 parts of amide solvent and / or sulfoxide solvent, 0-10 parts of non-solvent are stirred at a temperature of 30-90°C to obtain a polymer solution, and the polymer solution is filtered, degassed and aged to obtain a spinning solution; Step 2: Preparation of core solution 0-75 parts by weight of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, N,N-dimethylformamide and 25-100 parts by weight of pure water are prepared into a core liquid; Step 3: Dry-wet spinning The spinning solution and the core solution are extruded through the outer annular slit and the inner hole of two concentric hollow fiber spinning nozzles to form a hollow fiber membrane with a five-layer structure. The membrane is then formed in a coagulation bath through an air bath, and then stretched and wound in a plasticizing bath at a winding speed of 8-65 m / min. Step 4: Fiber post-processing Polydopamine and poly(methacrylic acid sulfobetaine) were fully dissolved in tris(hydroxymethylaminomethane) buffer with a pH value of 8.5, and the concentration of polydopamine was maintained at 2 mg / mL. The hollow fiber membrane was immersed in the solution, and co-deposited at 20-40°C for 1-12 h by 20-600kHz ultrasonic catalysis. The co-deposited hollow fiber membrane was then immersed in ethanol with a solid content of 20-100%, and heat-treated at 40-80°C for 2-8 h, and then dried in an oven at 30-60°C for 1-8 h to obtain the final hollow fiber membrane.

8. The method for preparing a polyethersulfone hollow fiber membrane for concentration and separation according to claim 7, characterized in that: The specific spinning conditions in step three are as follows: the spinneret and spinning solution temperatures are maintained at 25-90°C and 25-70°C respectively, the air humidity is maintained at 10-90%, the spinning solution pressure is 0.15-0.5 MPa, the spinning speed is 3-15 ml / min, and the core liquid flow rate is 15-55 ml / min.