Ultrafiltration membrane with high flux and anti-pollution performance and preparation method thereof

Abstract

The application relates to the technical field of ultrafiltration membranes, in particular to an ultrafiltration membrane with high flux and anti-pollution performance and a preparation method thereof. A polymer and hydroxyl-containing hydrophilic nanoparticles are dissolved in an organic solvent through stirring to obtain a first casting solution; a crosslinking polymer precursor is added into the first casting solution and dissolved through stirring to obtain a second casting solution; and an ultrafiltration membrane is obtained through an immersion precipitation phase inversion method. The hydroxyl-containing nanoparticles and the crosslinking polymer precursor are added into the polymer solution through a blending mode, the crosslinking polymer precursor in the polymer solution is hydrolyzed and condensed under the action of a catalyst and a crosslinking agent, and the hydroxyl-containing nanoparticles participate in the crosslinking reaction at the same time, so that the ultrafiltration membrane prepared from the polymer casting solution fundamentally endows the ultrafiltration membrane with stable anti-pollution performance, avoids the problem that an anti-pollution modifier blocks inherent pores of the membrane, and improves the membrane flux.

Description

Technical Field

[0001] This invention relates to the field of ultrafiltration membrane technology, and in particular to an ultrafiltration membrane with high flux and antifouling properties and its preparation method. Background Technology

[0002] Membrane separation technology, as an advanced water treatment technology, has advantages such as high separation efficiency, small footprint, simple operation, no phase change and no secondary pollution, and has gradually become a feasible technology to ensure drinking water safety.

[0003] Ultrafiltration, a pressure-driven membrane separation technology between microfiltration and nanofiltration, typically has a membrane pore size of 0.001-0.1 μm and an operating pressure of 0.1-1.0 MPa. Its separation principle is that under certain pressure, small-molecule solutes and solvents in the feed liquid can permeate through the membrane, while larger particles and macromolecular organic matter are retained due to sieving. Compared with other membrane separation technologies, ultrafiltration technology has advantages such as mild conditions, high separation efficiency, and low energy consumption, significantly improving the removal of organic pollutants and pathogenic microorganisms from water. Therefore, in practical industrial applications, ultrafiltration technology has been widely used in wastewater treatment, pharmaceutical purification, water purification, and fermentation and concentration in the food industry.

[0004] However, in the practical application of ultrafiltration technology, membrane fouling is a common key problem affecting the separation efficiency of ultrafiltration membranes, and the most fundamental solution is to prepare anti-fouling ultrafiltration membranes.

[0005] Currently, the main methods for preparing antifouling ultrafiltration membranes include: 1. Surface modification method: Ultrafiltration membranes are prepared using commercially available membrane-forming materials, and then the membrane surface is modified through techniques such as surface grafting or surface coating to obtain an antifouling ultrafiltration membrane. However, the ultrafiltration membrane prepared by this method only has antifouling properties on its surface. When the surface is damaged or contaminated, the membrane material performance deteriorates, and the antifouling modifier used can, to some extent, block the inherent pores of the membrane, reducing membrane flux. 2. Blending modification method: Antifouling modifiers such as hydrophilic polymers and hydrophilic inorganic nanomaterials are blended in the casting solution, and then an antifouling ultrafiltration membrane is prepared through a phase inversion method. However, this method suffers from poor interfacial compatibility due to differences in the properties of the antifouling modifier and the main membrane-forming material, as well as the problem of inorganic nanomaterial agglomeration. This hinders the improvement of membrane antifouling performance and easily leads to structural defects, resulting in poor antifouling performance and poor filtration accuracy.

[0006] To address the aforementioned issues, this application proposes a novel method for preparing an ultrafiltration membrane with high throughput and antifouling properties. Summary of the Invention

[0007] The purpose of this invention is to provide an ultrafiltration membrane with high flux and antifouling properties and a method for preparing the same. The prepared ultrafiltration membrane has stable antifouling properties as a whole, avoiding the problem of antifouling modifiers clogging the inherent pores of the membrane and improving the membrane flux.

[0008] This invention provides a method for preparing an ultrafiltration membrane with high flux and antifouling properties, comprising the following steps:

[0009] S1. The polymer and hydroxyl-containing hydrophilic nanoparticles are dissolved in an organic solvent by stirring to obtain the first casting solution.

[0010] S2. Add the cross-linked polymer precursor to the first casting solution, stir and dissolve to obtain the second casting solution;

[0011] S3. Using the immersion precipitation phase inversion method, an ultrafiltration membrane with high flux and antifouling properties is obtained;

[0012] The crosslinked polymer precursor includes any one of amino polymers and organosilicon sources.

[0013] In the preparation process of the ultrafiltration membrane of this invention, firstly, hydroxyl-containing hydrophilic nanoparticles are uniformly dispersed in an organic solvent of a polymer. Then, a crosslinking polymer precursor is added. During the hydrolysis and condensation of the crosslinking polymer precursor in the polymer solution, the hydroxyl-containing nanoparticles are simultaneously crosslinked into the three-dimensional network structure. Therefore, the resulting second casting solution is a polymer solution containing a three-dimensional network structure. By performing an immersion precipitation phase transformation, an ultrafiltration membrane with an overall sponge-like pore distribution structure and uniformly crosslinked and embedded hydrophilic nanoparticles within the sponge-like pores can be obtained. The ultrafiltration membrane prepared by this invention not only solves the problem of poor interfacial compatibility between the antifouling modifier and the main film-forming material, leading to the agglomeration of inorganic nanoparticles and structural defects, but also endows the ultrafiltration membrane with stable antifouling properties, avoiding the problem of antifouling modifiers clogging the inherent pores of the membrane, and improving membrane flux.

[0014] The crosslinking polymer precursor used only needs to be capable of undergoing hydrolysis and crosslinking reactions in the polymer solution, preferably an organosilicon source or an amino polymer that has already undergone a crosslinking reaction. When an organosilicon source is used, it undergoes hydrolysis and crosslinking reactions in the polymer solution, thereby simultaneously crosslinking the hydroxyl-containing nanoparticles into the network structure; when an amino polymer is used, the hydroxyl-containing nanoparticles and the amino polymer are crosslinked together due to the presence of strong intermolecular forces or hydrogen bonds.

[0015] As a preferred embodiment of this technical solution, to ensure the stability of the casting solution system and avoid excessive aggregation or precipitation of hydroxyl-containing hydrophilic nanoparticles, while simultaneously ensuring high membrane strength, the mass ratio of the polymer, the hydroxyl-containing hydrophilic nanoparticles, the crosslinked polymer precursor, and the organic solvent is (15-20):(0.5-2):(2-4):(70-85). Studies have shown that when the mass ratio of the polymer, the hydroxyl-containing hydrophilic nanoparticles, the crosslinked polymer precursor, and the organic solvent is 18:1:3:78, the resulting ultrafiltration membrane exhibits optimal performance.

[0016] As a preferred embodiment of this technical solution, the membrane substrate material used in this invention is preferably any one or more combinations of polyvinylidene fluoride, sulfonated polyethersulfone, polysulfone, and polyethersulfone, which have stable chemical properties, excellent acid and alkali resistance, high water permeability, and high strength.

[0017] As a preferred embodiment of this technical solution, the anti-pollution modifier containing hydroxyl hydrophilic nanoparticles used in this invention includes any one or more combinations of nano-silica, nano-titanium dioxide, nano-hydroxyapatite, and nano-ferric hydroxyoxide.

[0018] When amino polymers are selected as crosslinking polymer precursors, in order to further enhance the interaction between amino polymers and hydroxyl-containing hydrophilic nanoparticles, the amino polymers include any one or a combination of two of aminated silica and aminated titanium dioxide in any proportion.

[0019] In a preferred embodiment of this technical solution, the organosilicon source includes any one or a combination of two of tetraethyl orthosilicate and tetrabutyl titanate in any proportion. When the crosslinking polymer precursor is an organosilicon source, a catalyst and a crosslinking agent are added to further improve the hydrolysis and crosslinking effect of the organosilicon source. The catalyst includes any one or a combination of hydrochloric acid, acetic acid, and sulfuric acid. The crosslinking agent is KH550. Tetraethyl orthosilicate or tetrabutyl titanate undergoes hydrolysis under acidic conditions and crosslinks under the action of silane coupling agents such as KH550 or KH560. Simultaneously, hydroxyl-containing hydrophilic nanoparticles are also crosslinked into the three-dimensional network structure of tetraethyl orthosilicate or tetrabutyl titanate, thus solving the problem of aggregation of hydrophilic nanoparticles. The preferred mass ratio of the organosilicon source, the catalyst, and the crosslinking agent is (15-20):(0.5-2):(1-5).

[0020] As a preferred embodiment of this technical solution, the organic solvent includes any one or more combinations of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0021] As a preferred embodiment of this technical solution, in step S1, during the stirring and dissolution process, the mixture is stirred at 60-80°C for 3-8 hours to ensure that the hydroxyl-containing hydrophilic nanoparticles are uniformly dispersed in the polymer solution; in step S2, during the stirring and dissolution process, the mixture is stirred at 60-80°C for 12-36 hours to promote complete hydrolysis and crosslinking reactions.

[0022] As a preferred embodiment of this technical solution, in step S3, the coagulation bath in the immersion precipitation phase transformation method is water at a temperature of 25-30℃.

[0023] The ultrafiltration membrane prepared by the above method should also fall within the protection scope of this invention. Furthermore, the ultrafiltration membrane exhibits a permeation flux of 900-1000 L / (m²) for pure water at 0.1 MPa. 2 ·h).

[0024] The ultrafiltration membrane of the present invention, which has high flux and antifouling properties, has at least the following technical effects:

[0025] 1. In the preparation process of the ultrafiltration membrane of the present invention, hydroxyl-containing nanoparticles and cross-linked polymer precursors are added to the polymer solution through blending. While the cross-linked polymer precursors in the polymer solution undergo hydrolysis and condensation under the action of catalyst and cross-linking agent, the hydroxyl-containing nanoparticles simultaneously participate in the cross-linking reaction. Therefore, the resulting second casting solution is a uniform and stable polymer casting solution with simultaneous cross-linking modification of hydroxyl-containing hydrophilic nanoparticles and cross-linked polymer. Using this polymer casting solution for membrane preparation by phase inversion not only solves the problem of poor interfacial compatibility between the antifouling modifier and the main film-forming material, which leads to the agglomeration of inorganic nanoparticles and easy generation of structural defects, but also endows the ultrafiltration membrane with stable antifouling performance as a whole, avoids the problem of antifouling modifier clogging the inherent pores of the membrane, and improves the membrane flux.

[0026] 2. The ultrafiltration membrane prepared by the present invention has an overall sponge-like pore distribution structure, and hydrophilic nanoparticles are uniformly cross-linked and embedded inside the sponge-like pores. The pore size is relatively loose, which effectively reduces the mass transfer resistance and improves the filtration flux.

[0027] 3. In the preparation method of the present invention, with the introduction of hydroxyl-containing hydrophilic nanoparticles and cross-linked polymer precursors, the hydrophilicity of the polymer membrane is improved, which is beneficial to inhibit the aggregation of pollutants on the membrane surface, thereby improving the antifouling performance of the ultrafiltration membrane and improving the stability in actual use. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a SEM image of the surface of the ultrafiltration membrane prepared in Example 1 of the present invention;

[0030] Figure 2 This is a SEM image of the surface of the ultrafiltration membrane prepared in Comparative Example 1 of the present invention. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] Example 1

[0035] S11. Add 1g of nano-silica to 78g of N-methylpyrrolidone solvent and ultrasonically disperse it evenly at 80℃. Then add 18g of polyvinylidene fluoride and stir at 60℃ for 6h to form a uniform first casting solution.

[0036] S12. Add 3g of tetraethyl orthosilicate to the first casting solution, along with 0.1mL of 1mol / L hydrochloric acid and 0.2g of KH550. Stir at 60℃ for 25h to obtain a homogeneous second casting solution.

[0037] S13. After degassing the second casting solution, pour it onto a glass plate and use a doctor blade to spread the second casting solution into a continuous and uniform flat sheet liquid film. Then, quickly immerse the flat sheet liquid film in a 25°C water coagulation bath until the liquid film is completely solidified and detached from the glass plate. Subsequently, wash the solidified membrane in deionized water to remove residual N-methylpyrrolidone. Finally, dry the washed membrane to obtain an ultrafiltration flat sheet membrane with high flux and antifouling properties.

[0038] Example 2

[0039] S21. Add 0.5g of nano silica to 70g of N,N-dimethylformamide solvent and ultrasonically disperse it evenly at 70℃. Then add 15g of polyvinylidene fluoride and stir at 60℃ for 5h to form a uniform first casting solution.

[0040] S22. Add 2g of aminated titanium dioxide to the first casting solution and stir at 60℃ for 12h to obtain a homogeneous second casting solution.

[0041] S23. After degassing the second casting solution, pour it onto a glass plate and use a doctor blade to spread the second casting solution into a continuous and uniform flat sheet liquid film. Then, quickly immerse the flat sheet liquid film in a 25°C water coagulation bath until the liquid film is completely solidified and detached from the glass plate. Subsequently, wash the solidified membrane in deionized water to remove residual N,N-dimethylformamide. Finally, dry the washed membrane to obtain an ultrafiltration flat sheet membrane with high flux and antifouling properties.

[0042] Example 3

[0043] S31. Add 1.5g of nano silica to 80g of N,N-dimethylacetamide solvent and disperse it evenly by ultrasonication at 70℃. Then add 20g of polyvinylidene fluoride and stir at 60℃ for 8h to form a uniform first casting solution.

[0044] S32. Add 4g of tetraethyl orthosilicate to the first casting solution, along with 0.1mL of 1mol / L hydrochloric acid and 0.3g of KH550. Stir at 70℃ for 30h to obtain a homogeneous second casting solution.

[0045] S33. After degassing the second casting solution, pour it onto a glass plate and use a doctor blade to spread the second casting solution into a continuous and uniform flat sheet liquid film. Then, quickly immerse the flat sheet liquid film in a 25°C water coagulation bath until the liquid film is completely solidified and detached from the glass plate. Subsequently, wash the solidified membrane in deionized water to remove residual N,N-dimethylacetamide. Finally, dry the washed membrane to obtain an ultrafiltration flat sheet membrane with high flux and antifouling properties.

[0046] Example 4

[0047] S41. Add 1g of nano-iron hydroxyl oxide to 78g of dimethyl sulfoxide solvent and ultrasonically disperse it evenly at 80℃. Then add 18g of polyvinylidene fluoride and stir at 60℃ for 6h to form a uniform first casting solution.

[0048] S42. Add 3g of aminated silica to the first casting solution and stir at 60℃ for 15h to obtain a homogeneous second casting solution.

[0049] S43. After degassing the second casting solution, pour it onto a glass plate and use a doctor blade to spread the second casting solution into a continuous and uniform flat sheet liquid film. Then, quickly immerse the flat sheet liquid film in a 25°C water coagulation bath until the liquid film is completely solidified and detached from the glass plate. Subsequently, wash the solidified membrane in deionized water to remove residual dimethyl sulfoxide. Finally, dry the washed membrane to obtain an ultrafiltration flat sheet membrane with high flux and antifouling properties.

[0050] Compare with Example 1

[0051] S1. Add 1g of nano-silica to 78g of N-methylpyrrolidone solvent and disperse evenly. Then add 18g of polyvinylidene fluoride and stir at 60℃ for 6h to form a uniform first casting solution.

[0052] S2. After degassing the first casting solution, pour it onto a glass plate and use a doctor blade to spread the first casting solution into a continuous and uniform flat liquid film. Then, quickly immerse the flat liquid film in a 25°C water coagulation bath until the liquid film is completely solidified and detached from the glass plate. Subsequently, wash the solidified membrane in deionized water to remove residual N-methylpyrrolidone. Finally, dry the washed membrane to obtain the ultrafiltration flat sheet membrane.

[0053] Compare with Example 2

[0054] S1. Add 18g of polyvinylidene fluoride to 78g of N-methylpyrrolidone solvent and stir at 60℃ for 6h to form a homogeneous first casting solution.

[0055] S2. Add 3g of aminated silica to the first casting solution and stir at 60℃ for 25h to obtain a homogeneous second casting solution.

[0056] S3. After degassing the second casting solution, pour it onto a glass plate and use a doctor blade to spread the second casting solution into a continuous and uniform flat liquid film. Then, quickly immerse the flat liquid film in a 25°C water coagulation bath until the liquid film is completely solidified and detached from the glass plate. Subsequently, wash the solidified membrane in deionized water to remove residual N-methylpyrrolidone. Finally, dry the washed membrane to obtain an ultrafiltration flat sheet membrane with high flux and antifouling properties.

[0057] Compare with Example 3

[0058] S1. Add 18g of polyvinylidene fluoride to 78g of N-methylpyrrolidone solvent and stir at 60℃ for 6h to form a homogeneous first casting solution.

[0059] S2. Add 3g of tetraethyl orthosilicate, 0.1mL of 1mol / L HCl solution and 0.2g of KH550 to the first casting solution in sequence, and stir at 60℃ for 25h to obtain a homogeneous second casting solution.

[0060] S3. After degassing the second casting solution, pour it onto a glass plate and use a doctor blade to spread the second casting solution into a continuous and uniform flat liquid film. Then, quickly immerse the flat liquid film in a 25°C water coagulation bath until the liquid film is completely solidified and detached from the glass plate. Subsequently, wash the solidified membrane in deionized water to remove residual N-methylpyrrolidone. Finally, dry the washed membrane to obtain an ultrafiltration flat sheet membrane with high flux and antifouling properties.

[0061] To investigate the flux and antifouling properties of the ultrafiltration membranes prepared in Examples 1-4 and Comparative Examples 1-3, surface micromorphology analysis, contact angle testing, pure water flux testing, and antifouling performance testing were performed.

[0062] 1. Pure water flux test

[0063] The membrane was cut into test samples with a diameter of 3 cm and tested at room temperature, first under a pressure of 0.12 MPa.

[0064] Pre-pressurize for 1 hour, then change the pressure to 0.1 MPa and stabilize for 10 minutes. Perform a pure water flux test on the membrane, and record 5 as J. w (L·m -2 ·h -1 ), calculate according to the following formula:

[0065]

[0066] Where V is the permeate volume (L) and A is the effective filtration area of ​​the membrane (m²). 2 ), where t is the time (in hours) required for the filtrate to permeate to a volume V.

[0067] 2. Anti-pollution performance test

[0068] Preparation of bovine serum albumin solution: First, weigh out 8.00g NaCl, 0.20g KCl, and 2.88g Na₂HPO₄.

[0069] Dissolve 0.20 g KH₂PO₄ in water and bring the volume to 1.00 L to prepare PBS buffer. Weigh 1.00 g bovine serum albumin and add it to the PBS solution to prepare a 1.00 g / L PBS buffer. -1 Bovine serum albumin solution.

[0070] After the pure water flux test was completed, the pure water was replaced with bovine serum albumin solution, and the pressure was stabilized at 0.10 MPa for 10 min. The flux of the bovine serum albumin solution was then measured and recorded as J. B (L·m -2 ·h -1 After the flux stabilizes, collect the permeate and feed solution simultaneously. Use a UV-Vis spectrophotometer at a wavelength of 280 nm to measure the absorbance of the collected solution. Calculate the protein concentrations of the feed and permeate solutions using a standard curve, and calculate the membrane's protein rejection ratio (R) using the following formula:

[0071]

[0072] Among them, C p The concentration of bovine serum albumin in the osmotic fluid (g·L) -1 ), C f The concentration of bovine serum albumin in the feed solution (g·L) -1 ).

[0073] Under pressureless conditions, the membrane after filtering bovine serum albumin solution was rinsed for 10 minutes, and the pure water flux of the membrane was measured again, denoted as J. R Calculate the flux recovery rate (FRR) using the following formula:

[0074]

[0075] The FRR value represents the membrane's resistance to fouling; a higher FRR value indicates a higher resistance to fouling, and vice versa.

[0076] Table 1 Membrane performance test results

[0077] Example 1 56 959 96％ 93％ Example 2 71 702 84％ 83％ Example 3 53 986 94％ 93％ Example 4 60 763 85％ 90％ Compare with Example 1 73 405 82％ 80％ Compare with Example 2 70 452 85％ 82％ Compare with Example 3 75 507 86％ 84％

[0078] contrast Figure 1-2 It can be seen that the ultrafiltration membrane prepared in Example 1 of the present invention has an overall sponge-like pore distribution structure with a relatively loose pore size, and the hydroxyl-containing hydrophilic nanoparticles are uniformly distributed inside the membrane; while the ultrafiltration membrane prepared in Comparative Example 1 has the problem of inorganic nanoparticle aggregation.

[0079] As shown in Table 1, the ultrafiltration membranes prepared in Examples 1-4 of this invention exhibit significantly improved hydrophilicity compared to Control Examples 1-3, with water contact angles ranging from 53° to 71°. This indicates that the antifouling hydrophilic inorganic nanoparticles introduced through the simultaneous crosslinking of the crosslinked polymer precursor and hydroxyl-containing hydrophilic nanoparticles effectively enhance the membrane's hydrophilicity. Furthermore, the pure water flux and antifouling performance data show that, at 0.1 MPa, the pure water flux can reach 986 L / (m²). 2 The rejection rate of bovine serum albumin can reach 96%, and the flux recovery rate can reach 93%, further demonstrating that the hydrophilic nanoparticles introduced by the synchronous cross-linking method of the present invention significantly improve the antifouling performance of the membrane.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an ultrafiltration membrane with high flux and antifouling properties, characterized in that, Includes the following steps: S1. The polymer and hydroxyl-containing hydrophilic nanoparticles are dissolved in an organic solvent by stirring to obtain the first casting solution. S2. Add the cross-linked polymer precursor to the first casting solution, stir and dissolve to obtain the second casting solution; S3. The second casting solution is coated into a continuous and uniform flat liquid film by a doctor blade. The ultrafiltration membrane with high flux and antifouling performance is obtained by using the immersion precipitation phase inversion method. The crosslinking polymer precursor includes any one of an amino polymer and an organosilicon source; the mass ratio of the polymer, the hydroxyl-containing hydrophilic nanoparticles, the crosslinking polymer precursor, and the organic solvent is (15-20):(0.5-2):(2-4):(70-85); the hydroxyl-containing hydrophilic nanoparticles include any one or more combinations of nano-silica, nano-titanium dioxide, nano-hydroxyapatite, and nano-ferric hydroxyoxide; the amino polymer includes any one or a combination of two of aminated silica and aminated titanium dioxide in any proportion; the organosilicon source includes any one or a combination of two of tetraethyl orthosilicate and tetrabutyl titanate in any proportion; when the crosslinking polymer precursor is an organosilicon source, a catalyst and a crosslinking agent are also required.

2. The preparation method according to claim 1, characterized in that, The polymer includes any one or more combinations of polyvinylidene fluoride, sulfonated polyethersulfone, polysulfone, and polyethersulfone.

3. The preparation method according to claim 1, characterized in that, The catalyst includes any one or more combinations of hydrochloric acid, acetic acid, and sulfuric acid; The crosslinking agent is KH550; The mass ratio of the organosilicon source, the catalyst, and the crosslinking agent is (15-20):(0.5-2):(1-5).

4. The preparation method according to claim 1, characterized in that, The organic solvent includes any one or more combinations of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

5. The preparation method according to claim 1, characterized in that, In step S1, when stirring to dissolve, stir at 60-80℃ for 3-8 hours; In step S2, when dissolving the mixture, stir at 60-80℃ for 12-36 hours.

6. The preparation method according to claim 1, characterized in that, In step S3, the coagulation bath in the immersion precipitation phase transformation method is water at a temperature of 25-30℃.

7. An ultrafiltration membrane with high flux and antifouling properties, characterized in that, It is prepared by the preparation method according to any one of claims 1-6.

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