Polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination, preparation method and application thereof

Abstract

The present invention discloses a self-supporting polyethersulfone ultrafiltration membrane that resists biofouling, as well as its preparation method and application. The ultrafiltration membrane is produced by immobilizing cellulose nanocrystals and antibacterial ions on the surface and within the pores of the polyethersulfone membrane using polyphenol monomers. The self-supporting polyethersulfone ultrafiltration membrane can stably support hydrophilic and antibacterial materials, thereby imparting excellent hydrophilic properties and biofouling resistance, and can be efficiently and stably applied in water treatment or biological material processing.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination, and a preparation method and application thereof. Background Art

[0002] Membrane separation technology is a technique that uses the selective permeation principle of a membrane to separate one or more components from a mixture. This technology offers advantages such as high efficiency, environmental friendliness, and ease of operation, leading to its widespread application in water treatment, food and drug processing, biopharmaceuticals, and chemical engineering.

[0003] Membrane materials are the core component of membrane separation technology. Due to the inherent properties of membrane materials, microparticles, colloids, solute macromolecules, and biomacromolecules in the material passing through the membrane can be adsorbed and deposited on the membrane surface or within the membrane pores, causing the membrane pore size to decrease or become clogged. This ultimately leads to irreversible changes in the membrane's permeability and separation characteristics, affecting the efficiency and service life of the separation membrane. Among these factors, the adsorption of organic matter on the membrane surface is often the primary factor affecting membrane performance.

[0004] Research has confirmed that there is a positive correlation between membrane surface hydrophilicity and its resistance to organic fouling. The stronger the membrane surface hydrophilicity, the less organic matter adheres to the membrane surface. Therefore, improving membrane surface hydrophilicity is an important measure to mitigate membrane fouling.

[0005] Currently, effective strategies for improving the hydrophilicity of membrane surfaces mainly include membrane blending modification and surface modification. Blending modification involves blending nanoparticles, small molecules, or hydrophilic polymers with the membrane matrix to form a casting solution. The presence of hydrophilic fillers increases the hydrophilicity of the membrane surface, effectively improving the membrane's resistance to fouling. Blending modification offers the advantages of simplicity and low cost, but also has disadvantages such as poor compatibility with the polymer matrix, uneven dispersion, and easy loss. One method of membrane surface modification involves coating a hydrophilic material onto the membrane surface using van der Waals or electrostatic forces between the hydrophilic material and the membrane surface. This method is simple to operate, involves no chemical reaction, and is relatively low in cost. However, due to the weak interaction between the coating and the membrane surface, the hydrophilic functional layer can fall off during use, resulting in a problem with the membrane's surface hydrophilicity not being long-lasting. Surface chemical grafting modification is a reliable method for membrane surface treatment. Since the hydrophilic material is attached to the membrane surface via covalent bonds, the membrane's hydrophilic properties are effectively maintained during use. Generally, the process of this method is relatively cumbersome and in some cases may damage the intrinsic structure of the membrane, thereby affecting the mechanical properties of the membrane.

[0006] Cellulose is a natural polymer material with abundant resources and is biodegradable. After removing the amorphous region of cellulose, highly crystalline nanocellulose (CNC) is obtained. In recent years, with the development of degradable polymer composites, nanocellulose has attracted great attention. The inherent renewability, sustainability and environmental protection properties of CNC make it an ideal choice for the preparation of separation membranes. The surface of CNC has abundant hydroxyl groups (-OH) and is a highly hydrophilic material. Metal ions Ag + and Cu 2+ It has antibacterial properties and is widely used in the research of antibacterial membrane preparation. However, there is no effective way in the existing technology to combine hydrophilic materials and antibacterial ions on the surface and pores of self-supporting ultrafiltration membranes.

[0007] Therefore, there is an urgent need for a polyethersulfone self-supporting ultrafiltration membrane that can combine hydrophilic materials and antibacterial ions on the membrane surface and membrane pores to achieve excellent anti-fouling and hydrophilic properties and resist biofouling. Summary of the Invention

[0008] Purpose of the invention: In view of the defects of the prior art, the purpose of the present invention is to provide a polyethersulfone self-supporting ultrafiltration membrane that can act on the surface and pores of the membrane material with hydrophilic materials and antibacterial ions, thereby having excellent anti-fouling and hydrophilic properties and anti-biological contamination resistance, as well as its preparation method and application.

[0009] Technical solution:

[0010] On one hand, the present invention provides a polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination. The ultrafiltration membrane is prepared by fixing cellulose nanocrystals and antibacterial ions on the surface and in the membrane pores of the polyethersulfone membrane through polyphenol monomers.

[0011] In the present invention, the introduction of polyphenol monomers not only plays a role in immobilizing cellulose nanocrystals on the membrane surface and in the membrane pores, but also provides anchoring points for antibacterial nanomaterials, thus giving the polyethersulfone membrane excellent antibacterial properties.

[0012] Furthermore, the pore size of the ultrafiltration membrane is 30-100 nm, and the water contact angle is 25-40°.

[0013] The biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane provided by the present invention has excellent hydrophilicity and can be used to effectively treat water or biological materials.

[0014] Another aspect of the present invention provides a method for preparing any one of the above-mentioned anti-biofouling polyethersulfone self-supporting ultrafiltration membranes, comprising the following steps:

[0015] (1) Preparation of cellulose nanocrystals: After fragmenting the cellulose pulp, add an inorganic strong acid for acidification, mechanically stir under heating conditions, dilute with water, add an inorganic strong base solution to adjust the pH of the reaction system to 6.5-7.5, wash with deionized water, centrifuge, and freeze-dry to obtain cellulose nanocrystal powder;

[0016] (2) Preparation of polyethersulfone primary ultrafiltration membrane: dissolve polyethersulfone resin in solvent, add porogen and stir in oil bath to obtain uniform casting solution, cool down, degas, scrape the film on glass plate, place the glass plate in coagulation bath, and after the casting solution is peeled off from the glass plate, the polyethersulfone primary ultrafiltration membrane is obtained;

[0017] (3) Preparation of a polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination: The cellulose nanocrystal powder of step (1) is dissolved in pure water, ultrasonically treated, and then prepared into a cellulose nanocrystal aqueous solution. After suction filtration through the polyethersulfone primary ultrafiltration membrane of step (2), polyphenol monomers are weighed in a buffer solution of pH 8-9, and the solution is placed on the surface of the polyethersulfone membrane after suction filtration. At the same time, an inorganic salt and an oxidant are added. After contact, the solution is removed, and the polyethersulfone membrane is washed with pure water to obtain the polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination.

[0018] Furthermore, the raw material of the cellulose pulp board in step (1) is selected from at least one of wood, cotton, wheat straw, flax or waste paper;

[0019] The inorganic strong acid is selected from at least one of sulfuric acid, hydrochloric acid or phosphoric acid aqueous solution, and the inorganic strong base is selected from at least one of lithium hydroxide, sodium hydroxide or potassium hydroxide aqueous solution, and the concentration of the inorganic strong acid and the inorganic strong base is 5-15 mol / L;

[0020] The solid-liquid ratio during the acidification process is 0.1-0.5 and the temperature is 40-60°C.

[0021] For example, the solid-to-liquid ratio during the acidification process can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5;

[0022] The temperature can be 40°C, 45°C, 50°C, 55°C, 60°C.

[0023] Furthermore, the cellulose nanocrystal powder obtained in step (1) has a length of 50-100 nm and a diameter of 5-10 nm.

[0024] Furthermore, the solvent for the polyethersulfone resin in step (2) is a highly polar aprotic solvent;

[0025] The porogen is selected from at least one of acetone, ethanol, isopropanol, acetic acid, sodium chloride, sodium sulfate, calcium carbonate, sodium lauryl sulfate, polylactic acid or polycaprolactone;

[0026] The coagulation bath is carried out in pure water at 25-40°C.

[0027] For example, the highly polar aprotic solvent may be at least one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, or dimethyl sulfoxide.

[0028] Furthermore, based on the total mass fraction being 100%, the mass percentage of each component in the uniform casting solution in step (2) is:

[0029] Polyethersulfone resin 15-25%

[0030] Porogen 1-20%

[0031] The balance is solvent.

[0032] For example, the mass percentage of the polyethersulfone resin in the uniform casting solution may be 15%, 17.5%, 20%, 22.5%, or 25%;

[0033] The mass percentage of the porogen can be 1%, 3%, 5%, 8%, 10%, 12%, 15%, 18%, or 20%.

[0034] Furthermore, the concentration of the cellulose nanocrystal aqueous solution in step (3) is 0.05-0.3 g / L;

[0035] The polyphenol monomer is selected from at least one compound containing a catechol structure, the inorganic salt is selected from one of silver nitrate and copper sulfate, and the oxidant is selected from at least one of NaBH4 and hydrogen peroxide;

[0036] The addition amounts of the polyphenol monomer, inorganic salt and oxidant in the buffer solution are 1-5 g / L, 1-20 mmol / L and 2-100 mmol / L respectively; and the contact time is 5-120 min.

[0037] For example, the amount of polyphenol monomer added to the buffer solution can be 1 g / L, 2 g / L, 3 g / L, 4 g / L, or 5 g / L;

[0038] The amount of inorganic salt added to the buffer solution can be 1 mmol / L, 3 mmol / L, 5 mmol / L, 8 mmol / L, 10 mmol / L, 12 mmol / L, 15 mmol / L, 18 mmol / L, 20 mmol / L;

[0039] The amount of the oxidant added to the buffer solution can be 2 mmol / L, 5 mmol / L, 10 mmol / L, 20 mmol / L, 30 mmol / L, 40 mmol / L, 50 mmol / L, 60 mmol / L, 70 mmol / L, 80 mmol / L, 90 mmol / L, or 100 mmol / L.

[0040] For example, the buffer solution may be a weakly alkaline buffer solution of Tris-HCl with a concentration of 50-100 mM.

[0041] Furthermore, the contact time is 60-120 min.

[0042] For example, the contact time can be 60 min, 75 min, 90 min, 105 min, 120 min.

[0043] The present invention adopts a suction filtration method to physically fix the cellulose nanocrystals on the membrane surface and in the membrane pores, thereby ensuring that the membrane surface and the membrane pores are fully hydrophilic.

[0044] Furthermore, the polyphenol monomer is selected from at least one of dopamine, dopa, tannic acid, catechol or catechin compounds.

[0045] The present invention uses polyphenol monomers to fix cellulose nanocrystals, ensuring the in-situ solidification of cellulose nanocrystals on the membrane surface and in the membrane pores, avoiding the cellulose nanocrystals from falling off during the use of the membrane, and ensuring the durability of the anti-pollution performance of the immobilized cellulose nanocrystal membrane.

[0046] Finally, the present invention also provides the use of any one of the above-mentioned biofouling-resistant polyethersulfone self-supporting ultrafiltration membranes in water treatment or biological material treatment.

[0047] Beneficial effects:

[0048] 1. The anti-biofouling polyethersulfone self-supporting ultrafiltration membrane provided by the present invention is made by fixing cellulose nanocrystals and antibacterial ions on the surface and in the membrane pores of the polyethersulfone membrane through polyphenol monomers. This allows the membrane to stably load hydrophilic and antibacterial materials, thereby giving the ultrafiltration membrane excellent hydrophilic properties and anti-biofouling capabilities, enabling it to be efficiently and stably applied in the fields of water treatment or biological material treatment.

[0049] 2. In the preparation method of the anti-biological contamination polyethersulfone self-supporting ultrafiltration membrane provided by the present invention, cellulose nanocrystals are physically fixed to the membrane surface and membrane pores by suction filtration, ensuring that the membrane surface and membrane pores are fully hydrophilic.

[0050] 3. In the preparation method of the anti-biofouling polyethersulfone self-supporting ultrafiltration membrane provided by the present invention, polyphenol monomers are used to fix cellulose nanocrystals, ensuring the in-situ solidification of the cellulose nanocrystals on the membrane surface and in the membrane pores, avoiding the cellulose nanocrystals from falling off during the use of the membrane, and ensuring the durability of the anti-fouling performance of the immobilized cellulose nanocrystal membrane.

[0051] 4. The anti-biofouling polyethersulfone self-supporting ultrafiltration membrane provided by the present invention, through the introduction of polyphenol monomers, not only plays a role in immobilizing cellulose nanocrystals on the membrane surface and in the membrane pores, but also provides anchoring points for antibacterial nanomaterials, giving the polyethersulfone membrane excellent antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Figure 3 shows the change in the pure water flux recovery rate of the self-supporting polyethersulfone ultrafiltration membrane during the BSA enhanced pollution process, where the x-axis is the pollution time and the y-axis is the pure water flux recovery rate. DETAILED DESCRIPTION

[0053] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following examples are illustrative of the present invention and are intended only to illustrate the present invention and are not intended to limit the present invention. Other combinations and various modifications within the scope of the present invention may be made without departing from the spirit or scope of the present invention.

[0054] The polyethersulfone used is BASF brand (brand: E6020P); other raw materials without specified sources are common raw materials that can be purchased by those skilled in the art.

[0055] Example 1

[0056] A biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane is prepared by the following steps:

[0057] (1) Weigh 10.0 g of corn cobs, crush them with a crusher, acidify them with 100 g of 65% (mass fraction) H2SO4, and mechanically stir them in a constant temperature water bath at 50°C for 2 h. After the reaction is completed, dilute with water, adjust the reaction system to neutrality with 5 mol / L NaOH solution, wash with deionized water, centrifuge, and freeze-dry to obtain 6.4 g of CNC powder;

[0058] (2) Weigh 30.0 g of polyethersulfone and 10.0 g of acetic acid and dissolve them in 150 g of N,N-dimethylacetamide. Dissolve them in an oil bath at 60°C for 24 h to obtain a uniform casting solution. After cooling to room temperature, vacuum degassing was performed for 3 h. The casting solution was slowly poured onto a glass plate and scraped at a constant speed with a 250 μm scraper. The glass plate coated with the casting solution was then placed in pure water at 40°C. After the casting solution was peeled off from the glass plate, a self-supporting polyethersulfone ultrafiltration membrane was obtained.

[0059] (3) Weigh 0.075 g of CNC and dissolve it in 0.5 L of pure water. Ultrasonicate to obtain a 0.15 g / L CNC aqueous solution. Fix the polyethersulfone membrane in the membrane pool and filter. Prepare a Tris-HCl aqueous solution containing 5 mmol of CuSO4, 20 mmol of H2O2, and 2 g of dopamine hydrochloride. Adjust the pH to 8.5 and pour the solution on the surface of the polyethersulfone membrane after CNC filtration. Place it on a shaker for 60 min, then remove the buffer solution. Wash the polyethersulfone membrane with pure water to obtain a biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane.

[0060] Example 2

[0061] A biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane is prepared by the following steps:

[0062] Step (1) and step (2) are the same as in Example 1;

[0063] Step (3) was changed to weighing 0.15 g of CNC and dissolving it in 0.5 L of pure water, ultrasonically treating to obtain a 0.3 g / L CNC aqueous solution, fixing the polyethersulfone membrane in the membrane pool, filtering, preparing a 1 L Tris-HCl aqueous solution containing 5 mmol of CuSO4, 20 mmol of H2O2, and 2 g of dopamine hydrochloride, adjusting the pH to 8.5, pouring the solution on the surface of the polyethersulfone membrane after CNC filtration, placing it on a shaker for 60 min, then removing the buffer solution, washing the polyethersulfone membrane with pure water, and obtaining a biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane.

[0064] Example 3

[0065] A biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane is prepared by the following steps:

[0066] Step (1) and step (2) are the same as in Example 1;

[0067] Step (3) was changed to weighing 0.15 g of CNC and dissolving it in 0.5 L of pure water, ultrasonicating it to obtain a 0.3 g / L CNC aqueous solution, fixing the polyethersulfone membrane in the membrane pool, filtering it, preparing a 1 L Tris-HCl aqueous solution containing 5 mmol of CuSO4, 20 mmol of H2O2, and 2 g of dopamine hydrochloride, adjusting the pH to 8.5, pouring the solution on the surface of the polyethersulfone membrane after CNC filtration, placing it on a shaker for 120 min, then removing the buffer solution, and washing the polyethersulfone membrane with pure water to obtain a biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane.

[0068] Example 4

[0069] A biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane is prepared by the following steps:

[0070] Step (1) and step (3) are the same as in Example 1;

[0071] Step (2) was changed to weighing 36.0 g of polyethersulfone and 12.0 g of acetic acid and dissolving them in 150 g of N,N-dimethylacetamide, dissolving them in an oil bath at 60°C for 24 h to obtain a uniform casting solution. After cooling to room temperature, vacuum degassing was performed for 3 h, and the casting solution was slowly poured onto a glass plate. The film was scraped at a constant speed with a 250 μm scraper, and then the glass plate coated with the casting solution was placed in pure water at 40°C. After the casting solution was peeled off from the glass plate, a self-supporting polyethersulfone ultrafiltration membrane was obtained.

[0072] Comparative Example 1

[0073] A biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane is prepared by the following steps:

[0074] Step (1) and step (2) are the same as in Example 1;

[0075] Step (3) was changed to weighing 0.15 g of CNC and dissolving it in 0.5 L of pure water, ultrasonicating it to obtain a 0.3 g / L CNC aqueous solution, fixing the polyethersulfone membrane in the membrane pool, filtering it, preparing a 1 L Tris-HCl aqueous solution containing 20 mmol H2O2 and 2 g of dopamine hydrochloride, adjusting the pH to 8.5, pouring the solution on the surface of the polyethersulfone membrane after CNC filtration, placing it on a shaker for 1 h, then removing the buffer solution, washing the polyethersulfone membrane with pure water, and obtaining a biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane.

[0076] Comparative Example 2

[0077] A pollution-resistant polyethersulfone self-supporting ultrafiltration membrane is prepared by the following steps:

[0078] Step (1) and step (2) are the same as in Example 1;

[0079] Step (3) was changed to weighing 0.15 g of CNC and dissolving it in 0.5 L of pure water, ultrasonicating it to obtain a 0.3 g / L CNC aqueous solution, fixing the polyethersulfone membrane in the membrane pool, and filtering it to obtain a pollution-resistant polyethersulfone self-supporting ultrafiltration membrane.

[0080] Comparative Example 3

[0081] A polyethersulfone self-supporting ultrafiltration membrane is prepared by the following steps:

[0082] 30.0 g of polyethersulfone and 10.0 g of acetic acid were weighed and dissolved in 150 g of N,N-dimethylacetamide. The solution was dissolved in an oil bath at 60°C for 24 h to obtain a uniform casting solution. After cooling to room temperature, vacuum degassing was performed for 3 h. The casting solution was slowly poured onto a glass plate and scraped at a constant speed with a 250 μm scraper. The glass plate coated with the casting solution was then placed in pure water at 40°C. After the casting solution was peeled off from the glass plate, a self-supporting polyethersulfone ultrafiltration membrane was obtained.

[0083] Performance Testing

[0084] Pore ​​size test: The pore size test was performed on the polyethersulfone self-supporting structures prepared in steps (2) and (3) of Examples 1-4, Comparative Examples 1-2, and Comparative Example 3 using the gas-liquid replacement method. The infiltration liquid was Porefil. The test results are shown in Table 1.

[0085] Table 1

[0086]

[0087] Pure water contact angle test: Pure water contact angle tests were performed on the polyethersulfone self-supporting structures prepared in steps (2) and (3) of Examples 1-4, Comparative Examples 1-2, and Comparative Example 3, respectively. The test results are shown in Table 2.

[0088] Table 2

[0089]

[0090] According to the comparison of the test results in Table 1 and Table 2, the anti-biological fouling polyethersulfone self-supporting ultrafiltration membrane provided by the present invention has excellent hydrophilicity. After CNC membrane passing and polyphenol monomer fixation and loading of antibacterial ions, the contact angle of the ultrafiltration membrane surface can be effectively reduced, thereby improving the hydrophilicity.

[0091] Dynamic anti-pollution performance test: The polyethersulfone self-supporting ultrafiltration membranes prepared in Examples 1-4 and Comparative Examples 1-3 were subjected to dynamic anti-pollution performance tests.

[0092] Dynamic anti-fouling performance test process: The cross-flow membrane test bench was used for testing. First, the initial stable flux was tested with pure water. Then, under the test conditions of 300 ppm BSA aqueous solution, 1.0 bar operating pressure, temperature 25°C, and pH value 6.5-7.5, it was run for 8 hours and then rinsed with pure water for 10 minutes. The stable flux of pure water was tested and the flux recovery rate was calculated. The test was repeated 3 times. The results are shown in the table. Figure 1 .

[0093] according to Figure 1 From the comparison of the test results, it can be seen that the anti-biological fouling polyethersulfone self-supporting ultrafiltration membrane provided by the present invention has an excellent pure water flux recovery rate and can be used in the field of water treatment in a long-term and stable manner.

[0094] Antibacterial performance test: The static bacterial culture method was used for testing. Gram-negative bacteria ( E. coli ) and Gram-positive bacteria ( B. subtilis ) were cultured in LB medium at 37°C for 18 h until the bacteria reached the logarithmic growth phase (LB medium formula: tryptone 10 g / L, yeast extract 5 g / L, sodium chloride 10 g / L, pH 7.4). The membrane sheets (2.6×7.6 cm) of Examples 1-4 and Comparative Examples 1-3 were placed in a sterile culture dish and sterilized under ultraviolet irradiation for 30 min; 60 μL of bacterial suspension (concentration of about 1.0×10 6 CFU / mL, with physiological saline as the dispersion medium) was evenly coated on the membrane surface and covered with a glass slide to allow the bacterial solution to spread completely; the membrane was placed in a constant temperature incubator at 37°C for 3 h, and the bacteria on the membrane surface and the glass slide were collected with 9 mL of physiological saline, 1 mL of which was evenly mixed with nutrient agar; the culture dish was placed at 37°C for 48 h, and the colonies were counted and the inhibition rate was calculated. The test results are shown in Table 3.

[0095] Table 3

[0096]

[0097] According to the test results in Table 3, the anti-biological contamination polyethersulfone self-supporting ultrafiltration membrane provided by the present invention is 2+ During the process of PDA fixation of CNC, it was fixed on the membrane and showed good antibacterial effect against both Gram-negative and Gram-positive bacteria, and had excellent anti-biological contamination ability.

[0098] The above embodiments are only for illustrating the technical concept and features of the present invention. Its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination, characterized in that: The ultrafiltration membrane is prepared by fixing cellulose nanocrystals and antibacterial ions on the surface and in the pores of a polyethersulfone membrane using polyphenol monomers; The pore size of the ultrafiltration membrane is 30-100 nm, and the water contact angle is 25-40°; The method for preparing the anti-biological contamination polyethersulfone self-supporting ultrafiltration membrane comprises the following steps: (1) Preparation of cellulose nanocrystals: After fragmenting the cellulose pulp, add an inorganic strong acid for acidification, mechanically stir under heating conditions, dilute with water, add an inorganic strong base solution to adjust the pH of the reaction system to 6.5-7.5, wash with deionized water, centrifuge, and freeze-dry to obtain cellulose nanocrystal powder; (2) Preparation of polyethersulfone primary ultrafiltration membrane: dissolve polyethersulfone resin in solvent, add porogen and stir in oil bath to obtain uniform casting solution, cool down, degas, scrape the film on glass plate, place the glass plate in coagulation bath, and after the casting solution is peeled off from the glass plate, the polyethersulfone primary ultrafiltration membrane is obtained; (3) Preparation of a polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination: The cellulose nanocrystal powder of step (1) is dissolved in pure water, ultrasonically treated, and then prepared into a cellulose nanocrystal aqueous solution. After suction filtration through the polyethersulfone primary ultrafiltration membrane of step (2), polyphenol monomers are weighed in a buffer solution of pH 8-9, and the solution is placed on the surface of the polyethersulfone membrane after suction filtration. At the same time, an inorganic salt and an oxidant are added. After contact, the solution is removed, and the polyethersulfone membrane is washed with pure water to obtain the polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination.

2. The polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination according to claim 1, characterized in that: The raw material of the cellulose pulp board in step (1) is selected from at least one of wood, cotton, wheat straw, flax or waste paper; The inorganic strong acid is selected from at least one of sulfuric acid, hydrochloric acid or phosphoric acid aqueous solution, and the inorganic strong base is selected from at least one of lithium hydroxide, sodium hydroxide or potassium hydroxide aqueous solution, and the concentration of the inorganic strong acid and the inorganic strong base is 5-15 mol / L; The solid-liquid ratio during the acidification process is 0.1-0.5 g / g and the temperature is 40-60°C.

3. The polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination according to claim 1, characterized in that: The cellulose nanocrystal powder obtained in step (1) has a length of 50-100 nm and a diameter of 5-10 nm.

4. The polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination according to claim 1, characterized in that: The solvent for the polyethersulfone resin in step (2) is a highly polar aprotic solvent; The porogen is selected from at least one of acetone, ethanol, isopropanol, acetic acid, sodium chloride, sodium sulfate, calcium carbonate, sodium lauryl sulfate, polylactic acid or polycaprolactone; The coagulation bath is carried out in pure water at 25-40°C.

5. The polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination according to claim 1, characterized in that: Taking the total mass fraction as 100%, the mass percentage of each component in the uniform casting solution in step (2) is: Polyethersulfone resin 15-25% Porogen 1-20% The balance is solvent.

6. The polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination according to claim 1, characterized in that: The concentration of the cellulose nanocrystal aqueous solution in step (3) is 0.05-0.3 g / L; The polyphenol monomer is selected from at least one compound containing a catechol structure, the inorganic salt is copper sulfate, and the oxidant is hydrogen peroxide; The addition amounts of the polyphenol monomer, inorganic salt and oxidant in the buffer solution are 1-5 g / L, 1-20 mmol / L and 2-100 mmol / L respectively; and the contact time is 5-120 min.

7. The polyethersulfone self-supporting ultrafiltration membrane resistant to biological contamination according to claim 1, characterized in that: The polyphenol monomer is selected from at least one of dopamine, dopa, tannic acid, catechol or catechin compounds.

8. Use of the biofouling-resistant polyethersulfone self-supporting ultrafiltration membrane according to any one of claims 1 to 7 in water treatment or biological material treatment.

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