Modified MABR hollow fiber membrane as well as preparation method and application thereof

Abstract

The invention discloses a modified MABR hollow fiber membrane as well as a preparation method and application thereof, and the modified MABR hollow fiber membrane comprises a fluororesin hollow fiber membrane and a modified layer arranged on the fluororesin hollow fiber membrane, the modified layer comprises a cross-linked substance generated by reaction of a compound shown in a formula (I) and a compound shown in a formula (II) and a molecular sieve dispersed in the cross-linked substance; in the formula (I), R1 is selected from H or C1-6 alkyl, and n is greater than or equal to 1; in the formula (II), R2 is selected from H or C1-6 alkyl; during preparation, the modified slurry is applied to the fluororesin hollow fiber membrane for crosslinking, and the modified MABR hollow fiber membrane has the advantages of good wettability, high surface roughness, good ammonia nitrogen enrichment capability and the like, and can be used in sewage treatment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more particularly to gas adsorption materials, specifically to a modified MABR hollow fiber membrane, its preparation method, and its application. Background Technology

[0002] Over the past few decades, the global wastewater treatment industry has developed rapidly, making significant progress in removing pollutants and protecting public health and the aquatic environment. Consequently, national and local governments have placed higher demands on wastewater treatment effectiveness, with an increasing number of regions issuing their own high-quality upgrading and renovation standards. These high-quality standards aim far higher than the national Class A standard. With each standard upgrade, the most technically challenging aspect is the total nitrogen index, putting conventional denitrification processes under pressure for technological upgrades once again. Improving denitrification efficiency using the activated sludge process with forced aeration is particularly difficult, as seen with conventional Class A standards. 2 Combining the A / O process with the A / O denitrification process to form a multi-stage AO process, or adding various denitrification filters after the biological treatment process, not only results in excessive energy consumption, excessively long process routes, and additional land use, but most importantly, it puts enormous pressure on the operation, maintenance, and management of wastewater treatment plants.

[0003] A membrane-aerated biofilm reactor (MABR) is a technology that uses an oxygen-permeable membrane as a biofilm carrier to directly transfer oxygen to aerobic bacteria through bubble-free aeration. This provides favorable ecological niches for both nitrifying and denitrifying bacteria, while the oxygen-permeable membrane offers a larger attachment surface area for water treatment microorganisms, resulting in a smaller overall tank volume compared to the activated sludge process. MABR technology can be applied to many areas, including municipal / domestic sewage treatment, industrial wastewater treatment, sponge city construction, lakes, landscape water bodies, and rivers (including black and odorous water bodies and Class V water bodies) for rapid and efficient oxygenation.

[0004] The core of MABR technology lies in providing gaseous substrates and an oxygen-permeable membrane for microbial attachment. The surface properties of the oxygen-permeable membrane determine the supply rate of gaseous substrates and the amount of water treatment microorganisms that attach, which is particularly important for improving denitrification efficiency. However, in practice, it has been found that microporous membranes with good air permeability are easily fouled, while dense membranes with better antifouling capabilities require higher aeration pressures. Mass-produced oxygen-permeable membranes often have relatively smooth surfaces and lack substrate enrichment functions, which is not conducive to microbial attachment and growth, resulting in a clear trade-off.

[0005] It should be noted that the information disclosed in the background section above is only for understanding the background of this application. Therefore, the background section of this invention may include background information about the problems or environment of this invention, and is not necessarily a description of the prior art. Thus, the content included in the background section does not constitute an admission of the prior art by the applicant. Summary of the Invention

[0006] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide a modified MABR hollow fiber membrane that has the advantages of good wettability, high surface roughness, and good ammonia nitrogen enrichment capacity.

[0007] The present invention also provides a method for preparing the above-mentioned modified MABR hollow fiber membrane and its application in wastewater treatment.

[0008] To achieve the above objectives, the present invention employs the following technical solution: A modified MABR hollow fiber membrane, the modified MABR hollow fiber membrane comprising a fluoropolymer hollow fiber membrane and a modified layer disposed on the fluoropolymer hollow fiber membrane, the modified layer comprising a crosslinker generated by reacting a compound of formula (I) with a compound of formula (II) and a molecular sieve dispersed in the crosslinker; In equation (Ⅰ), R1 is selected from H or C. 1-6 Alkyl group, n ≥ 1; In equation (II), R2 is selected from H or C. 1-6 alkyl.

[0009] In some embodiments of the present invention, the fluoropolymer hollow fiber membrane is a hollow fiber membrane made of one or more materials selected from polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), and polyvinyl fluoride (PVF).

[0010] In some embodiments of the present invention, the fluororesin hollow fiber of the fluororesin hollow fiber membrane has a pore size of 1-80 nm.

[0011] In some embodiments of the present invention, the water contact angle of the fluoropolymer hollow fiber membrane is less than or equal to 95°, for example, it can be 85° to 95°.

[0012] According to one specific aspect of the present invention, the fluoropolymer hollow fiber membrane is a PVDF hollow fiber membrane, which can be commercially available or prepared according to conventional methods in the art.

[0013] In some embodiments of the present invention, R1 is selected from H, methyl or ethyl.

[0014] In some embodiments of the present invention, R2 is selected from H, methyl or ethyl.

[0015] In some embodiments of the present invention, the degree of polymerization of the compound represented by formula (Ⅰ) is 1600-1800 and the degree of alcoholysis is 90%-99%.

[0016] According to one specific aspect of the present invention, the compound represented by formula (I) is polyvinyl alcohol (PVA).

[0017] According to one specific aspect of the present invention, the compound represented by formula (II) is N,N-methylenebisacrylamide (MBA).

[0018] In some embodiments of the present invention, the molecular sieve is a synthetic zeolite with a particle size of 10 μm or less. For example, it can be ZSM-5 type synthetic zeolite with a particle size of 10 μm or less.

[0019] Another technical solution provided by the present invention: a method for preparing the modified MABR hollow fiber membrane described above, the preparation method comprising: The compound shown in formula (I), the compound shown in formula (II), the molecular sieve, and the crosslinking initiator are mixed and homogenized to prepare a coating material; The coating material is applied to the fluoropolymer hollow fiber membrane and crosslinked under heating conditions.

[0020] In some embodiments of the present invention, the mass ratio of the compound represented by formula (I), the compound represented by formula (II), and the crosslinking initiator is 1:0.05-0.15:0.1-0.2.

[0021] In some embodiments of the present invention, the compound represented by formula (Ⅰ) accounts for 2%-12% and the molecular sieve accounts for 0.5%-8% by mass percentage in the coating material.

[0022] Furthermore, in terms of mass percentage, the compound represented by formula (Ⅰ) accounts for 3.5%-9.5% of the coating material, for example, it can be 4%, 5%, 6%, 7%, 8%, 9%, etc.

[0023] Furthermore, based on mass percentage, the molecular sieve in the coating material may account for 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.2%, 1.5%, 2%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 9.0%, etc.

[0024] In some embodiments of the present invention, the crosslinking initiator comprises ammonium persulfate.

[0025] In some embodiments of the present invention, the crosslinking temperature is controlled at 65-120°C, and further, the crosslinking time is controlled at 0.5-4 hours.

[0026] According to some specific aspects of the invention, for example, the crosslinking temperature is controlled at 75-85°C and the crosslinking time is 1.5-2.5 hours; For example, the cross-linking temperature is controlled at 115-125℃ and the cross-linking time is 0.3-0.8 hours.

[0027] In some embodiments of the present invention, the preparation method further includes a step of pretreating the fluororesin hollow fiber membrane before applying the coating material to the fluororesin hollow fiber membrane; The pretreatment method includes: sealing both ends of the fluororesin hollow fiber membrane, first immersing it in anhydrous ethanol, then immersing it in deionized water, then rinsing the surface with deionized water, repeating the process of immersion and rinsing with deionized water, and then drying it.

[0028] Furthermore, the two ends of the fluororesin hollow fiber membrane are sealed by methods such as bundling and sealing with waterproof potting compound.

[0029] In some embodiments of the present invention, the method for preparing the coating material includes: dispersing the compound shown in formula (I) in water, stirring at 70-90°C until clear and transparent, then adding molecular sieves, mixing well to obtain a mixture, cooling, adding the compound shown in formula (II) and a crosslinking initiator, and stirring to mix.

[0030] Furthermore, before adding the molecular sieve, the molecular sieve is heated to 60-90℃.

[0031] In some embodiments of the present invention, the coating material is applied to the fluoropolymer hollow fiber membrane by means of impregnation or the like.

[0032] According to some specific aspects of the present invention, the method for preparing the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: Seal both ends of the fluoropolymer hollow fiber membrane and immerse it in anhydrous ethanol. After immersion in ethanol, the fluoropolymer hollow fiber membrane is further immersed in deionized water, and then the surface is rinsed with deionized water. Repeat the deionized water immersion and rinsing process multiple times (e.g., 3 to 5 times), and air dry at room temperature. Preparation of coating material: The weighed compound shown in formula (I) is placed in water and stirred thoroughly in an oil bath at 70~90℃ until it is clear and transparent to obtain a solution of compound shown in formula (I) with a certain mass fraction. Molecular sieve material is added to the solution of compound shown in formula (I) and mixed thoroughly to form a uniform mixture. After the mixture is cooled, compound shown in formula (II) and crosslinking initiator are added and stirred until completely dissolved to form a coating solution. The coating solution is placed in a room temperature environment to stand and defoam, and the coating material is obtained. 2) Coating treatment: The pretreated fluoropolymer hollow fiber membrane, sealed at both ends, is immersed in the coating material. 3) Crosslinking: The coated fluoropolymer hollow fiber membrane is placed in an oven for crosslinking to obtain a modified MABR hollow fiber membrane.

[0033] Furthermore, during the coating process in step 2), the fully impregnated fluoropolymer hollow fiber membrane can be pulled out of the coating material at a constant speed. According to the LLD (Landau, Levich, Derjaguin) law, a uniform liquid film can be formed on the surface of the fluoropolymer hollow fiber membrane. ; In the formula, Ca is a dimensionless number, η is the viscosity of the coating material, γ is the surface tension of the coating material, and υ is the speed at which the fluoropolymer hollow fiber membrane is removed from the coating liquid. ; In the formula, h is the thickness of the liquid film, and r is the radius of the fluororesin hollow fiber in the fluororesin hollow fiber membrane.

[0034] Furthermore, the crosslinking process of the present invention is roughly as follows: ; During the reaction, under the initiation of an initiator such as ammonium persulfate (APS), persulfate ions generate sulfate radicals under heating (≥65°C), which generate carbon radicals in the molecular chain of the compound shown in formula (I) (e.g., polyvinyl alcohol). The generated carbon radicals react with the vinyl segments of the molecular chain of the compound shown in formula (II) (N,N-methylenebisacrylamide (MBA)) to form a spatial cross-linked network that coats the porous artificial zeolite onto the fluoropolymer hollow fiber membrane, for example, by coating the surface. The cross-linked compound shown in formula (II) has a low degree of swelling in water, and the cross-linking reaction does not consume the hydroxyl groups in the PVA molecular chain, thus retaining hydrophilicity.

[0035] Another technical solution provided by the present invention is the application of the modified MABR hollow fiber membrane described above, or the modified MABR hollow fiber membrane prepared by the preparation method described above, in wastewater treatment.

[0036] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art: The modified MABR hollow fiber membrane of this invention exhibits good wettability and high roughness, possessing ammonia nitrogen enrichment capacity. Simultaneously, the cross-linked compound (I) (e.g., polyvinyl alcohol) and molecular sieve material are stably loaded and will not dissolve or release into the water, balancing the increased contact angle caused by the molecular sieve material load. Therefore, it is generally beneficial for the collision and adhesion between water treatment microorganisms and the composite membrane, resulting in a large adhesion area while effectively reducing the buffering effect, with a maximum enrichment capacity of 4.50 × 10⁻⁶. 2 mg NH4 + -N / m 2 This is beneficial for water treatment microorganisms to adhere and grow on the surface of the composite membrane, and the start-up time of MABR is shortened by about 34%. Attached Figure Description

[0037] Figure 1 This is a physical image of the MABR hollow fiber membrane obtained in Comparative Example 1 of the present invention. Figure 2 This is a physical image of the MABR hollow fiber membrane obtained in Comparative Example 3 of the present invention. Figure 3 This is a photograph of the modified MABR hollow fiber membrane obtained in Example 6 of the present invention. Figure 4 This is a 5000x SEM image of the MABR hollow fiber membrane obtained in Comparative Example 1 of this invention. Figure 5 This is a 5000x SEM image of the MABR hollow fiber membrane obtained in Comparative Example 3 of this invention. Figure 6 This is a 5000x SEM image of the modified MABR hollow fiber membrane obtained in Example 6 of the present invention. Figure 7 This is a 50,000x SEM image of the modified MABR hollow fiber membrane obtained in Example 6 of the present invention. Figure 8 The image shows the AFM pattern of the MABR hollow fiber membrane obtained in Comparative Example 1 of this invention. Figure 9 The image shown is the AFM image of the modified MABR hollow fiber membrane obtained in Example 6 of this invention. Figure 10 The curves showing the changes in ammonia nitrogen adsorption capacity of the modified MABR hollow fiber membranes obtained in Examples 1-9 of this invention with the addition amounts of PVA and ZSM-5 type artificial zeolite are shown. Figure 11 This is a photograph of the MABR hollow fiber membrane obtained in Comparative Example 1 of this invention after 15 days of membrane attachment. Figure 12 This is a photograph of the modified MABR hollow fiber membrane obtained in Example 6 of this invention after 15 days of membrane attachment. Figure 13 The curves showing the changes in TIN concentration and TIN removal rate of the influent and effluent over time during the period from self-attachment to stable operation of the MABR in Comparative Example 1 and Example 6 of this invention are shown. Detailed Implementation

[0038] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0039] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0040] In the following, the PVDF hollow fiber membrane has an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; polyvinyl alcohol (PVA) was purchased from Shanghai Titan Technology Co., Ltd., DAMAS-beta, polyvinyl alcohol 17-99, product number: 014188083; and ZSM-5 type artificial zeolite with a particle size ≤10 μm was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., brand name Aladdin#P103646-250g.

[0041] Example 1: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 5 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 1 part of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.5 parts of N,N-methylenebisacrylamide (MBA) and 0.75 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0042] Example 2: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 5 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 5 parts of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.5 parts of N,N-methylenebisacrylamide (MBA) and 0.75 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0043] Example 3: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 5 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 8 parts of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.5 parts of N,N-methylenebisacrylamide (MBA) and 0.75 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0044] Example 4: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 7 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 1 part of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.7 parts of N,N-methylenebisacrylamide (MBA) and 1.05 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0045] Example 5: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 7 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 5 parts of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.7 parts of N,N-methylenebisacrylamide (MBA) and 1.05 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0046] Example 6: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 7 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 8 parts of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.7 parts of N,N-methylenebisacrylamide (MBA) and 1.05 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0047] Example 7: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 9 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 1 part of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.9 parts of N,N-methylenebisacrylamide (MBA) and 1.35 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0048] Example 8: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 9 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 5 parts of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.9 parts of N,N-methylenebisacrylamide (MBA) and 1.35 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0049] Example 9: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 9 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; ZSM-5 type artificial zeolite with a particle size ≤10μm was preheated in an 80℃ oven to dry the moisture and prevent agglomeration caused by excessive temperature difference during the mixing process. Add 8 parts of preheated ZSM-5 type artificial zeolite to the PVA aqueous solution and mix thoroughly for 30 minutes to form a uniform mixture. Continue stirring the mixture and cool it to room temperature. Add 0.9 parts of N,N-methylenebisacrylamide (MBA) and 1.35 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form a coating solution. Place the coating solution in a room temperature environment to stand and defoam, and obtain the coated material. 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0050] Comparative Example 1: This example provides a blank MABR hollow fiber membrane and its preparation method. The preparation method of the blank MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of blank solution: Deionized water was placed in a 90℃ oil bath and stirred thoroughly for 2 hours to obtain blank solution; 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in blank solution for 2 hours, and then pull it out of the blank solution at a constant speed of 5 cm / s; 3) Heat treatment: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for 2 hours to obtain a blank MABR hollow fiber membrane.

[0051] Comparative Example 2: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 5 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; cool to room temperature, add 0.5 parts of N,N-methylenebisacrylamide (MBA) and 0.75 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form coating solution, place the coating solution in a room temperature environment to stand and defoam, and obtain coating material; 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0052] Comparative Example 3: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 7 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; cool to room temperature, add 0.7 parts of N,N-methylenebisacrylamide (MBA) and 1.05 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form coating solution; place the coating solution in a room temperature environment to stand and defoam to obtain coating material; 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0053] Comparative Example 4: This example provides a modified MABR hollow fiber membrane and its preparation method. The preparation method of the modified MABR hollow fiber membrane includes: 1) Pretreatment of the base membrane: The base membrane is a PVDF hollow fiber membrane with an outer diameter of 2.1 mm, an inner diameter of 1.1 mm, and a maximum pore size of 80 nm; The PVDF hollow fiber membrane is sealed at both ends to prevent liquid from remaining inside the membrane cavity. Then it is immersed in anhydrous ethanol for 12 hours to remove organic matter attached to the surface. After ethanol immersion, the PVDF hollow fiber membrane is immersed in deionized water for 10 minutes, and then the surface is rinsed with deionized water. The deionized water immersion and rinsing process is repeated 4 times to remove residual ethanol. It is then air-dried at room temperature to prevent the subsequent coating material from being diluted on the surface. Preparation of coating material: Add 9 parts by weight of PVA to 100 parts by weight of water, place in a 90℃ oil bath and stir thoroughly for 2 hours until clear and transparent to obtain PVA aqueous solution; cool to room temperature, add 0.9 parts of N,N-methylenebisacrylamide (MBA) and 1.35 parts of initiator ammonium persulfate (APS) and stir until completely dissolved to form coating solution; place the coating solution in a room temperature environment to stand and defoam to obtain coating material; 2) Coating treatment: Immerse the pretreated PVDF hollow fiber membrane in the coating material for 2 hours. After full wetting, pull it out of the coating material at a constant speed of 5cm / s. 3) Crosslinking: The coated PVDF hollow fiber membrane is placed in an 80℃ oven for crosslinking for 2 hours to obtain the modified MABR hollow fiber membrane.

[0054] Performance testing: (1) Figure 1 This is a photograph of the MABR hollow fiber membrane obtained in Comparative Example 1 of this invention. Figure 2 This is a photograph of the MABR hollow fiber membrane obtained in Comparative Example 3 of the present invention. Figure 3 This is a photograph of the modified MABR hollow fiber membrane obtained in Example 6 of the present invention. Figure 4 This is a 5000x SEM image of the MABR hollow fiber membrane obtained in Comparative Example 1 of this invention. Figure 5 This is a 5000x SEM image of the MABR hollow fiber membrane obtained in Comparative Example 3 of this invention. Figure 6 This is a 5000x SEM image of the modified MABR hollow fiber membrane obtained in Example 6 of the present invention. Figure 7The image shows a 50,000x SEM of the modified MABR hollow fiber membrane obtained in Example 6 of this invention. It can be seen that the cross-linked PVA successfully loaded the molecular sieve onto the surface of the hollow fiber membrane, and the surface was almost completely covered, resulting in a significant change in morphology. Figure 8 This is the AFM image of the MABR hollow fiber membrane obtained in Comparative Example 1 of this invention. Figure 9 The image shows the AFM image of the modified MABR hollow fiber membrane obtained in Example 6 of the present invention. It can be seen that the modified MABR hollow fiber membrane obtained in the present invention has a high surface roughness. The root mean square roughness of Comparative Example 1 is 18.4 nm, and the root mean square roughness of Example 6 is 590 nm. The large adhesion area effectively reduces the buffering effect, which is conducive to the adhesion of microorganisms. Figure 10 This is a photograph of the MABR hollow fiber membrane obtained in Comparative Example 1 of this invention after 15 days of membrane attachment. Figure 11 This is a photograph of the modified MABR hollow fiber membrane obtained in Example 6 of the present invention after 15 days of biofilm formation. It can be seen that the modified MABR hollow fiber membrane of the present invention has more and more uniform biofilm attached to its surface.

[0055] (2) The water contact angle of the MABR hollow fiber membrane obtained in Comparative Example 1 was measured to be 93.91°, the water contact angle of the MABR hollow fiber membrane obtained in Comparative Example 3 was 95.89°, and the water contact angle of the modified MABR hollow fiber membrane obtained in Example 6 was 108.5°. It can be seen that the modification method in this invention did not lead to a significant change in wettability. The cross-linked PVA balanced part of the high hydrophobicity brought by the molecular sieve.

[0056] (3) Ammonia nitrogen adsorption test a. Sample preparation Hollow fiber membranes were cut into 50mm segments, and both ends were sealed with waterproof potting compound to prevent interference from the inner surface of the membrane to the experiment. The sealed membranes were then immersed in anhydrous ethanol for 12 hours, followed by immersion in deionized water for 2 hours and rinsing. This immersion and rinsing process was repeated three times. The prepared samples were then dried in an oven.

[0057] b. Sample regeneration The regeneration solution is an aqueous solution consisting of 0.1M NaOH and 1M NaCl; Take 10 dried membrane samples and completely immerse them in an appropriate amount of regeneration solution, shaking for 12 hours. Thoroughly rinse the membrane sample surface with deionized water. Detect the ammonia nitrogen concentration in the regeneration solution after use. If the ammonia nitrogen concentration is not 0 mg / L, repeat the regeneration process until no ammonia nitrogen is detected in the regeneration solution. Dry the regenerated membrane in an oven.

[0058] c. Adsorption experiment A concentration of approximately 50 mg NH4 was prepared using anhydrous NH4Cl.+ For a solution with -N / L concentration, the actual concentration of the solution is recorded as C0. Take NH4Cl solution in an Erlenmeyer flask as the adsorption solution.

[0059] The regenerated membrane was completely immersed in the adsorption solution in an Erlenmeyer flask, which was then placed in a 25°C water bath with constant temperature shaking for 24 hours for adsorption. The ammonia nitrogen concentration in the NH4Cl solution after the adsorption process was measured and recorded as C. The ammonia nitrogen adsorption capacity per unit membrane area, A, was calculated using the following formula: ; Where: V: volume of adsorption solution, liters (L); C0: Initial concentration of the adsorbent, mg / L; C: Concentration of the adsorbent solution after adsorption, mg / L; n: Number of membrane roots; D: Outer diameter of membrane, meters (m); L: Membrane length, meters (m).

[0060] The maximum ammonia nitrogen adsorption capacity per unit area of ​​the hollow fiber membranes obtained in Examples 1-9 and Comparative Examples 1-4 was measured, as shown in Tables 1 to 3.

[0061] Table 1. Maximum ammonia nitrogen adsorption capacity per unit area in Examples 1-3 and Comparative Examples 1-2

[0062] Table 2. Maximum ammonia nitrogen adsorption capacity per unit area of ​​Examples 4-6 and Comparative Examples 1 and 3

[0063] Table 3 Maximum ammonia nitrogen adsorption capacity per unit area of ​​Examples 7-9 and Comparative Examples 1 and 4

[0064] Tables 1-3 show that: Comparative Example 1 indicates that the original PVDF hollow fiber membrane has almost no ammonia nitrogen adsorption capacity, and therefore does not enrich the substrate; Comparative Examples 2-4 indicate that the cross-linked PVA network, due to its hydrophilicity and certain swelling properties, has a small amount of ammonia nitrogen enrichment capacity, but the increase in concentration does not have a substantial and significant effect on the adsorption amount; Examples 4, 5, and 6 show that when the PVA concentration is constant, increasing the molecular sieve concentration can increase the molecular sieve loading in the modified layer of the PVDF hollow fiber membrane, thereby increasing the ammonia nitrogen adsorption amount; Examples 3, 6, and 9 show that although increasing the PVA concentration will increase the molecular sieve loading in the skin layer of the PVDF hollow fiber composite membrane, excessively high concentrations will form a denser and thicker skin layer, causing the molecular sieve to be completely coated, reducing the ammonia nitrogen adsorption amount.

[0065] (4) MABR running experiment The membrane module in the experimental reactor consisted of 138 hollow fiber membranes. The reactor's working volume was 1.27 L, and the area-to-volume ratio was 200.16 m². -1 The influent is synthetic domestic sewage, with a nitrogen source of 50 mg NH4. + Ammonium sulfate with -N / L, sodium acetate with a carbon source of 300 mg COD / L, trace element solution of 10 ml / L, and operating temperature of 23-25℃ maintained by air conditioning.

[0066] Figure 13 The graph shows the influent and effluent TIN (total inorganic nitrogen) data of the hollow fiber membrane in Comparative Example 1 and the modified hollow fiber membrane in Example 6 of this invention from the time of membrane attachment to the time of stable operation. It can be found that the effluent TIN of the MABR in Comparative Example 1 is higher than that in Example 6 throughout the entire operation period (except for the flow pattern disruption caused by sampling on the 20th day). At the same time, the start-up time of the MABR in Comparative Example 1 is about 39-41 days, while the start-up time of the MABR in Example 6 is about 27-30 days. The modified hollow fiber membrane in Comparative Example 6 obtained by this invention is conducive to microbial attachment, thereby shortening the biofilm maturation time, retaining more biomass, and thus optimizing the denitrification effect.

[0067] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0068] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A modified MABR hollow fiber membrane, characterized in that, The modified MABR hollow fiber membrane includes a fluoropolymer hollow fiber membrane and a modified layer disposed on the fluoropolymer hollow fiber membrane. The modified layer comprises a crosslinker generated by reacting the compound shown in formula (I) with the compound shown in formula (II) and a molecular sieve dispersed in the crosslinker. In equation (Ⅰ), R1 is selected from H or C. 1-6 Alkyl group, n ≥ 1; In formula (II), R2 is selected from H or C. 1-6 alkyl.

2. The modified MABR hollow fiber membrane according to claim 1, characterized in that, The fluoropolymer hollow fiber membrane is a hollow fiber membrane made of one or more materials selected from polytetrafluoroethylene, polychlorotrifluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and polyvinylidene fluoride; and / or, the fluoropolymer hollow fibers of the fluoropolymer hollow fiber membrane have a pore size of 1-80 nm.

3. The modified MABR hollow fiber membrane according to claim 1, characterized in that, R1 is selected from H, methyl or ethyl; and / or, R2 is selected from H, methyl or ethyl; and / or, the degree of polymerization of the compound represented by formula (I) is 1600-1800 and the degree of alcoholysis is 90%-99%.

4. The modified MABR hollow fiber membrane according to claim 1, characterized in that, The molecular sieve is a synthetic zeolite with a particle size of less than or equal to 10 μm.

5. A method for preparing the modified MABR hollow fiber membrane according to any one of claims 1-4, characterized in that, The preparation method includes: The compound shown in formula (I), the compound shown in formula (II), the molecular sieve, and the crosslinking initiator are mixed and homogenized to prepare a coating material; The coating material is applied to the fluoropolymer hollow fiber membrane and crosslinked under heating conditions.

6. The method for preparing the modified MABR hollow fiber membrane according to claim 5, characterized in that, The mass ratio of the compound represented by formula (I), the compound represented by formula (II), and the crosslinking initiator is 1:0.05-0.15:0.1-0.2; and / or, by mass percentage, the compound represented by formula (I) accounts for 2%-12% and the molecular sieve accounts for 0.5%-8% in the coating material; further, the compound represented by formula (I) accounts for 3.5%-9.5%; and / or, the crosslinking initiator comprises ammonium persulfate.

7. The method for preparing the modified MABR hollow fiber membrane according to claim 5, characterized in that, The crosslinking temperature is controlled at 65-120°C, and the crosslinking time is controlled at 0.5-4 hours.

8. The method for preparing the modified MABR hollow fiber membrane according to claim 5, characterized in that, The preparation method further includes a step of pretreating the fluororesin hollow fiber membrane before applying the coating material to the fluororesin hollow fiber membrane; The pretreatment method includes: sealing both ends of the fluororesin hollow fiber membrane, first immersing it in anhydrous ethanol, then immersing it in deionized water, then rinsing the surface with deionized water, repeating the process of immersion and rinsing with deionized water, and then drying it.

9. The method for preparing the modified MABR hollow fiber membrane according to claim 5, characterized in that, The method for preparing the coating material includes: dispersing the compound shown in formula (I) in water, stirring at 70-90°C until clear and transparent, then adding molecular sieves, mixing well to obtain a mixture, cooling and then adding the compound shown in formula (II) and a crosslinking initiator, and stirring to mix; Furthermore, before adding the molecular sieve, the molecular sieve is heated to 60-90℃.

10. The application of a modified MABR hollow fiber membrane according to any one of claims 1-4, or a modified MABR hollow fiber membrane prepared by the preparation method according to any one of claims 5-9, in wastewater treatment.

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